initial code repo

This patch creates initial code repo.

For ceph, luminous stable release will be used for base code,
and next changes and optimization for ceph will be added to it.

For opensds, currently any changes can be upstreamed into original
opensds repo (https://github.com/opensds/opensds), and so stor4nfv
will directly clone opensds code to deploy stor4nfv environment.
And the scripts for deployment based on ceph and opensds will be
put into 'ci' directory.

Change-Id: I46a32218884c75dda2936337604ff03c554648e4
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>

33 files changed, 10708 insertions, 0 deletions

diff --git a/src/ceph/qa/tasks/cephfs/__init__.py b/src/ceph/qa/tasks/cephfs/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/__init__.py
diff --git a/src/ceph/qa/tasks/cephfs/cephfs_test_case.py b/src/ceph/qa/tasks/cephfs/cephfs_test_case.py
new file mode 100644
index 0000000..801d0d3
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/cephfs_test_case.py
@@ -0,0 +1,315 @@
+import json
+import logging
+from unittest import case
+from tasks.ceph_test_case import CephTestCase
+import os
+import re
+from StringIO import StringIO
+
+from tasks.cephfs.fuse_mount import FuseMount
+
+from teuthology.orchestra import run
+from teuthology.orchestra.run import CommandFailedError
+
+
+log = logging.getLogger(__name__)
+
+
+def for_teuthology(f):
+    """
+    Decorator that adds an "is_for_teuthology" attribute to the wrapped function
+    """
+    f.is_for_teuthology = True
+    return f
+
+
+def needs_trimming(f):
+    """
+    Mark fn as requiring a client capable of trimming its cache (i.e. for ceph-fuse
+    this means it needs to be able to run as root, currently)
+    """
+    f.needs_trimming = True
+    return f
+
+
+class CephFSTestCase(CephTestCase):
+    """
+    Test case for Ceph FS, requires caller to populate Filesystem and Mounts,
+    into the fs, mount_a, mount_b class attributes (setting mount_b is optional)
+
+    Handles resetting the cluster under test between tests.
+    """
+
+    # FIXME weird explicit naming
+    mount_a = None
+    mount_b = None
+    recovery_mount = None
+
+    # Declarative test requirements: subclasses should override these to indicate
+    # their special needs.  If not met, tests will be skipped.
+    CLIENTS_REQUIRED = 1
+    MDSS_REQUIRED = 1
+    REQUIRE_KCLIENT_REMOTE = False
+    REQUIRE_ONE_CLIENT_REMOTE = False
+    REQUIRE_MEMSTORE = False
+
+    # Whether to create the default filesystem during setUp
+    REQUIRE_FILESYSTEM = True
+
+    # requires REQUIRE_FILESYSTEM = True
+    REQUIRE_RECOVERY_FILESYSTEM = False
+
+    LOAD_SETTINGS = []
+
+    def setUp(self):
+        super(CephFSTestCase, self).setUp()
+
+        if len(self.mds_cluster.mds_ids) < self.MDSS_REQUIRED:
+            raise case.SkipTest("Only have {0} MDSs, require {1}".format(
+                len(self.mds_cluster.mds_ids), self.MDSS_REQUIRED
+            ))
+
+        if len(self.mounts) < self.CLIENTS_REQUIRED:
+            raise case.SkipTest("Only have {0} clients, require {1}".format(
+                len(self.mounts), self.CLIENTS_REQUIRED
+            ))
+
+        if self.REQUIRE_KCLIENT_REMOTE:
+            if not isinstance(self.mounts[0], FuseMount) or not isinstance(self.mounts[1], FuseMount):
+                # kclient kill() power cycles nodes, so requires clients to each be on
+                # their own node
+                if self.mounts[0].client_remote.hostname == self.mounts[1].client_remote.hostname:
+                    raise case.SkipTest("kclient clients must be on separate nodes")
+
+        if self.REQUIRE_ONE_CLIENT_REMOTE:
+            if self.mounts[0].client_remote.hostname in self.mds_cluster.get_mds_hostnames():
+                raise case.SkipTest("Require first client to be on separate server from MDSs")
+
+        if self.REQUIRE_MEMSTORE:
+            objectstore = self.mds_cluster.get_config("osd_objectstore", "osd")
+            if objectstore != "memstore":
+                # You certainly *could* run this on a real OSD, but you don't want to sit
+                # here for hours waiting for the test to fill up a 1TB drive!
+                raise case.SkipTest("Require `memstore` OSD backend to simulate full drives")
+
+        # Create friendly mount_a, mount_b attrs
+        for i in range(0, self.CLIENTS_REQUIRED):
+            setattr(self, "mount_{0}".format(chr(ord('a') + i)), self.mounts[i])
+
+        self.mds_cluster.clear_firewall()
+
+        # Unmount all clients, we are about to blow away the filesystem
+        for mount in self.mounts:
+            if mount.is_mounted():
+                mount.umount_wait(force=True)
+
+        # To avoid any issues with e.g. unlink bugs, we destroy and recreate
+        # the filesystem rather than just doing a rm -rf of files
+        self.mds_cluster.mds_stop()
+        self.mds_cluster.mds_fail()
+        self.mds_cluster.delete_all_filesystems()
+        self.fs = None # is now invalid!
+        self.recovery_fs = None
+
+        # In case the previous filesystem had filled up the RADOS cluster, wait for that
+        # flag to pass.
+        osd_mon_report_interval_max = int(self.mds_cluster.get_config("osd_mon_report_interval_max", service_type='osd'))
+        self.wait_until_true(lambda: not self.mds_cluster.is_full(),
+                             timeout=osd_mon_report_interval_max * 5)
+
+        # In case anything is in the OSD blacklist list, clear it out.  This is to avoid
+        # the OSD map changing in the background (due to blacklist expiry) while tests run.
+        try:
+            self.mds_cluster.mon_manager.raw_cluster_cmd("osd", "blacklist", "clear")
+        except CommandFailedError:
+            # Fallback for older Ceph cluster
+            blacklist = json.loads(self.mds_cluster.mon_manager.raw_cluster_cmd("osd",
+                                  "dump", "--format=json-pretty"))['blacklist']
+            log.info("Removing {0} blacklist entries".format(len(blacklist)))
+            for addr, blacklisted_at in blacklist.items():
+                self.mds_cluster.mon_manager.raw_cluster_cmd("osd", "blacklist", "rm", addr)
+
+        client_mount_ids = [m.client_id for m in self.mounts]
+        # In case the test changes the IDs of clients, stash them so that we can
+        # reset in tearDown
+        self._original_client_ids = client_mount_ids
+        log.info(client_mount_ids)
+
+        # In case there were any extra auth identities around from a previous
+        # test, delete them
+        for entry in self.auth_list():
+            ent_type, ent_id = entry['entity'].split(".")
+            if ent_type == "client" and ent_id not in client_mount_ids and ent_id != "admin":
+                self.mds_cluster.mon_manager.raw_cluster_cmd("auth", "del", entry['entity'])
+
+        if self.REQUIRE_FILESYSTEM:
+            self.fs = self.mds_cluster.newfs(create=True)
+            self.fs.mds_restart()
+
+            # In case some test messed with auth caps, reset them
+            for client_id in client_mount_ids:
+                self.mds_cluster.mon_manager.raw_cluster_cmd_result(
+                    'auth', 'caps', "client.{0}".format(client_id),
+                    'mds', 'allow',
+                    'mon', 'allow r',
+                    'osd', 'allow rw pool={0}'.format(self.fs.get_data_pool_name()))
+
+            # wait for mds restart to complete...
+            self.fs.wait_for_daemons()
+
+            # Mount the requested number of clients
+            for i in range(0, self.CLIENTS_REQUIRED):
+                self.mounts[i].mount()
+                self.mounts[i].wait_until_mounted()
+
+        if self.REQUIRE_RECOVERY_FILESYSTEM:
+            if not self.REQUIRE_FILESYSTEM:
+                raise case.SkipTest("Recovery filesystem requires a primary filesystem as well")
+            self.fs.mon_manager.raw_cluster_cmd('fs', 'flag', 'set',
+                                                'enable_multiple', 'true',
+                                                '--yes-i-really-mean-it')
+            self.recovery_fs = self.mds_cluster.newfs(name="recovery_fs", create=False)
+            self.recovery_fs.set_metadata_overlay(True)
+            self.recovery_fs.set_data_pool_name(self.fs.get_data_pool_name())
+            self.recovery_fs.create()
+            self.recovery_fs.getinfo(refresh=True)
+            self.recovery_fs.mds_restart()
+            self.recovery_fs.wait_for_daemons()
+
+        # Load an config settings of interest
+        for setting in self.LOAD_SETTINGS:
+            setattr(self, setting, float(self.fs.mds_asok(
+                ['config', 'get', setting], self.mds_cluster.mds_ids[0]
+            )[setting]))
+
+        self.configs_set = set()
+
+    def tearDown(self):
+        super(CephFSTestCase, self).tearDown()
+
+        self.mds_cluster.clear_firewall()
+        for m in self.mounts:
+            m.teardown()
+
+        for i, m in enumerate(self.mounts):
+            m.client_id = self._original_client_ids[i]
+
+        for subsys, key in self.configs_set:
+            self.mds_cluster.clear_ceph_conf(subsys, key)
+
+    def set_conf(self, subsys, key, value):
+        self.configs_set.add((subsys, key))
+        self.mds_cluster.set_ceph_conf(subsys, key, value)
+
+    def auth_list(self):
+        """
+        Convenience wrapper on "ceph auth ls"
+        """
+        return json.loads(self.mds_cluster.mon_manager.raw_cluster_cmd(
+            "auth", "ls", "--format=json-pretty"
+        ))['auth_dump']
+
+    def assert_session_count(self, expected, ls_data=None, mds_id=None):
+        if ls_data is None:
+            ls_data = self.fs.mds_asok(['session', 'ls'], mds_id=mds_id)
+
+        alive_count = len([s for s in ls_data if s['state'] != 'killing'])
+
+        self.assertEqual(expected, alive_count, "Expected {0} sessions, found {1}".format(
+            expected, alive_count
+        ))
+
+    def assert_session_state(self, client_id,  expected_state):
+        self.assertEqual(
+            self._session_by_id(
+                self.fs.mds_asok(['session', 'ls'])).get(client_id, {'state': None})['state'],
+            expected_state)
+
+    def get_session_data(self, client_id):
+        return self._session_by_id(client_id)
+
+    def _session_list(self):
+        ls_data = self.fs.mds_asok(['session', 'ls'])
+        ls_data = [s for s in ls_data if s['state'] not in ['stale', 'closed']]
+        return ls_data
+
+    def get_session(self, client_id, session_ls=None):
+        if session_ls is None:
+            session_ls = self.fs.mds_asok(['session', 'ls'])
+
+        return self._session_by_id(session_ls)[client_id]
+
+    def _session_by_id(self, session_ls):
+        return dict([(s['id'], s) for s in session_ls])
+
+    def wait_for_daemon_start(self, daemon_ids=None):
+        """
+        Wait until all the daemons appear in the FSMap, either assigned
+        MDS ranks or in the list of standbys
+        """
+        def get_daemon_names():
+            return [info['name'] for info in self.mds_cluster.status().get_all()]
+
+        if daemon_ids is None:
+            daemon_ids = self.mds_cluster.mds_ids
+
+        try:
+            self.wait_until_true(
+                lambda: set(daemon_ids) & set(get_daemon_names()) == set(daemon_ids),
+                timeout=30
+            )
+        except RuntimeError:
+            log.warn("Timeout waiting for daemons {0}, while we have {1}".format(
+                daemon_ids, get_daemon_names()
+            ))
+            raise
+
+    def assert_mds_crash(self, daemon_id):
+        """
+        Assert that the a particular MDS daemon crashes (block until
+        it does)
+        """
+        try:
+            self.mds_cluster.mds_daemons[daemon_id].proc.wait()
+        except CommandFailedError as e:
+            log.info("MDS '{0}' crashed with status {1} as expected".format(daemon_id, e.exitstatus))
+            self.mds_cluster.mds_daemons[daemon_id].proc = None
+
+            # Go remove the coredump from the crash, otherwise teuthology.internal.coredump will
+            # catch it later and treat it as a failure.
+            p = self.mds_cluster.mds_daemons[daemon_id].remote.run(args=[
+                "sudo", "sysctl", "-n", "kernel.core_pattern"], stdout=StringIO())
+            core_pattern = p.stdout.getvalue().strip()
+            if os.path.dirname(core_pattern):  # Non-default core_pattern with a directory in it
+                # We have seen a core_pattern that looks like it's from teuthology's coredump
+                # task, so proceed to clear out the core file
+                log.info("Clearing core from pattern: {0}".format(core_pattern))
+
+                # Determine the PID of the crashed MDS by inspecting the MDSMap, it had
+                # to talk to the mons to get assigned a rank to reach the point of crashing
+                addr = self.mds_cluster.mon_manager.get_mds_status(daemon_id)['addr']
+                pid_str = addr.split("/")[1]
+                log.info("Determined crasher PID was {0}".format(pid_str))
+
+                # Substitute PID into core_pattern to get a glob
+                core_glob = core_pattern.replace("%p", pid_str)
+                core_glob = re.sub("%[a-z]", "*", core_glob)  # Match all for all other % tokens
+
+                # Verify that we see the expected single coredump matching the expected pattern
+                ls_proc = self.mds_cluster.mds_daemons[daemon_id].remote.run(args=[
+                    "sudo", "ls", run.Raw(core_glob)
+                ], stdout=StringIO())
+                cores = [f for f in ls_proc.stdout.getvalue().strip().split("\n") if f]
+                log.info("Enumerated cores: {0}".format(cores))
+                self.assertEqual(len(cores), 1)
+
+                log.info("Found core file {0}, deleting it".format(cores[0]))
+
+                self.mds_cluster.mds_daemons[daemon_id].remote.run(args=[
+                    "sudo", "rm", "-f", cores[0]
+                ])
+            else:
+                log.info("No core_pattern directory set, nothing to clear (internal.coredump not enabled?)")
+
+        else:
+            raise AssertionError("MDS daemon '{0}' did not crash as expected".format(daemon_id))
diff --git a/src/ceph/qa/tasks/cephfs/filesystem.py b/src/ceph/qa/tasks/cephfs/filesystem.py
new file mode 100644
index 0000000..9638fd5
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/filesystem.py
@@ -0,0 +1,1213 @@
+
+from StringIO import StringIO
+import json
+import logging
+from gevent import Greenlet
+import os
+import time
+import datetime
+import re
+import errno
+import random
+
+from teuthology.exceptions import CommandFailedError
+from teuthology import misc
+from teuthology.nuke import clear_firewall
+from teuthology.parallel import parallel
+from tasks.ceph_manager import write_conf
+from tasks import ceph_manager
+
+
+log = logging.getLogger(__name__)
+
+
+DAEMON_WAIT_TIMEOUT = 120
+ROOT_INO = 1
+
+
+class ObjectNotFound(Exception):
+    def __init__(self, object_name):
+        self._object_name = object_name
+
+    def __str__(self):
+        return "Object not found: '{0}'".format(self._object_name)
+
+class FSStatus(object):
+    """
+    Operations on a snapshot of the FSMap.
+    """
+    def __init__(self, mon_manager):
+        self.mon = mon_manager
+        self.map = json.loads(self.mon.raw_cluster_cmd("fs", "dump", "--format=json"))
+
+    def __str__(self):
+        return json.dumps(self.map, indent = 2, sort_keys = True)
+
+    # Expose the fsmap for manual inspection.
+    def __getitem__(self, key):
+        """
+        Get a field from the fsmap.
+        """
+        return self.map[key]
+
+    def get_filesystems(self):
+        """
+        Iterator for all filesystems.
+        """
+        for fs in self.map['filesystems']:
+            yield fs
+
+    def get_all(self):
+        """
+        Iterator for all the mds_info components in the FSMap.
+        """
+        for info in self.get_standbys():
+            yield info
+        for fs in self.map['filesystems']:
+            for info in fs['mdsmap']['info'].values():
+                yield info
+
+    def get_standbys(self):
+        """
+        Iterator for all standbys.
+        """
+        for info in self.map['standbys']:
+            yield info
+
+    def get_fsmap(self, fscid):
+        """
+        Get the fsmap for the given FSCID.
+        """
+        for fs in self.map['filesystems']:
+            if fscid is None or fs['id'] == fscid:
+                return fs
+        raise RuntimeError("FSCID {0} not in map".format(fscid))
+
+    def get_fsmap_byname(self, name):
+        """
+        Get the fsmap for the given file system name.
+        """
+        for fs in self.map['filesystems']:
+            if name is None or fs['mdsmap']['fs_name'] == name:
+                return fs
+        raise RuntimeError("FS {0} not in map".format(name))
+
+    def get_replays(self, fscid):
+        """
+        Get the standby:replay MDS for the given FSCID.
+        """
+        fs = self.get_fsmap(fscid)
+        for info in fs['mdsmap']['info'].values():
+            if info['state'] == 'up:standby-replay':
+                yield info
+
+    def get_ranks(self, fscid):
+        """
+        Get the ranks for the given FSCID.
+        """
+        fs = self.get_fsmap(fscid)
+        for info in fs['mdsmap']['info'].values():
+            if info['rank'] >= 0:
+                yield info
+
+    def get_rank(self, fscid, rank):
+        """
+        Get the rank for the given FSCID.
+        """
+        for info in self.get_ranks(fscid):
+            if info['rank'] == rank:
+                return info
+        raise RuntimeError("FSCID {0} has no rank {1}".format(fscid, rank))
+
+    def get_mds(self, name):
+        """
+        Get the info for the given MDS name.
+        """
+        for info in self.get_all():
+            if info['name'] == name:
+                return info
+        return None
+
+    def get_mds_addr(self, name):
+        """
+        Return the instance addr as a string, like "10.214.133.138:6807\/10825"
+        """
+        info = self.get_mds(name)
+        if info:
+            return info['addr']
+        else:
+            log.warn(json.dumps(list(self.get_all()), indent=2))  # dump for debugging
+            raise RuntimeError("MDS id '{0}' not found in map".format(name))
+
+class CephCluster(object):
+    @property
+    def admin_remote(self):
+        first_mon = misc.get_first_mon(self._ctx, None)
+        (result,) = self._ctx.cluster.only(first_mon).remotes.iterkeys()
+        return result
+
+    def __init__(self, ctx):
+        self._ctx = ctx
+        self.mon_manager = ceph_manager.CephManager(self.admin_remote, ctx=ctx, logger=log.getChild('ceph_manager'))
+
+    def get_config(self, key, service_type=None):
+        """
+        Get config from mon by default, or a specific service if caller asks for it
+        """
+        if service_type is None:
+            service_type = 'mon'
+
+        service_id = sorted(misc.all_roles_of_type(self._ctx.cluster, service_type))[0]
+        return self.json_asok(['config', 'get', key], service_type, service_id)[key]
+
+    def set_ceph_conf(self, subsys, key, value):
+        if subsys not in self._ctx.ceph['ceph'].conf:
+            self._ctx.ceph['ceph'].conf[subsys] = {}
+        self._ctx.ceph['ceph'].conf[subsys][key] = value
+        write_conf(self._ctx)  # XXX because we don't have the ceph task's config object, if they
+                               # used a different config path this won't work.
+
+    def clear_ceph_conf(self, subsys, key):
+        del self._ctx.ceph['ceph'].conf[subsys][key]
+        write_conf(self._ctx)
+
+    def json_asok(self, command, service_type, service_id):
+        proc = self.mon_manager.admin_socket(service_type, service_id, command)
+        response_data = proc.stdout.getvalue()
+        log.info("_json_asok output: {0}".format(response_data))
+        if response_data.strip():
+            return json.loads(response_data)
+        else:
+            return None
+
+
+class MDSCluster(CephCluster):
+    """
+    Collective operations on all the MDS daemons in the Ceph cluster.  These
+    daemons may be in use by various Filesystems.
+
+    For the benefit of pre-multi-filesystem tests, this class is also
+    a parent of Filesystem.  The correct way to use MDSCluster going forward is
+    as a separate instance outside of your (multiple) Filesystem instances.
+    """
+    def __init__(self, ctx):
+        super(MDSCluster, self).__init__(ctx)
+
+        self.mds_ids = list(misc.all_roles_of_type(ctx.cluster, 'mds'))
+
+        if len(self.mds_ids) == 0:
+            raise RuntimeError("This task requires at least one MDS")
+
+        if hasattr(self._ctx, "daemons"):
+            # Presence of 'daemons' attribute implies ceph task rather than ceph_deploy task
+            self.mds_daemons = dict([(mds_id, self._ctx.daemons.get_daemon('mds', mds_id)) for mds_id in self.mds_ids])
+
+    def _one_or_all(self, mds_id, cb, in_parallel=True):
+        """
+        Call a callback for a single named MDS, or for all.
+
+        Note that the parallelism here isn't for performance, it's to avoid being overly kind
+        to the cluster by waiting a graceful ssh-latency of time between doing things, and to
+        avoid being overly kind by executing them in a particular order.  However, some actions
+        don't cope with being done in parallel, so it's optional (`in_parallel`)
+
+        :param mds_id: MDS daemon name, or None
+        :param cb: Callback taking single argument of MDS daemon name
+        :param in_parallel: whether to invoke callbacks concurrently (else one after the other)
+        """
+        if mds_id is None:
+            if in_parallel:
+                with parallel() as p:
+                    for mds_id in self.mds_ids:
+                        p.spawn(cb, mds_id)
+            else:
+                for mds_id in self.mds_ids:
+                    cb(mds_id)
+        else:
+            cb(mds_id)
+
+    def get_config(self, key, service_type=None):
+        """
+        get_config specialization of service_type="mds"
+        """
+        if service_type != "mds":
+            return super(MDSCluster, self).get_config(key, service_type)
+
+        # Some tests stop MDS daemons, don't send commands to a dead one:
+        service_id = random.sample(filter(lambda i: self.mds_daemons[i].running(), self.mds_daemons), 1)[0]
+        return self.json_asok(['config', 'get', key], service_type, service_id)[key]
+
+    def mds_stop(self, mds_id=None):
+        """
+        Stop the MDS daemon process(se).  If it held a rank, that rank
+        will eventually go laggy.
+        """
+        self._one_or_all(mds_id, lambda id_: self.mds_daemons[id_].stop())
+
+    def mds_fail(self, mds_id=None):
+        """
+        Inform MDSMonitor of the death of the daemon process(es).  If it held
+        a rank, that rank will be relinquished.
+        """
+        self._one_or_all(mds_id, lambda id_: self.mon_manager.raw_cluster_cmd("mds", "fail", id_))
+
+    def mds_restart(self, mds_id=None):
+        self._one_or_all(mds_id, lambda id_: self.mds_daemons[id_].restart())
+
+    def mds_fail_restart(self, mds_id=None):
+        """
+        Variation on restart that includes marking MDSs as failed, so that doing this
+        operation followed by waiting for healthy daemon states guarantees that they
+        have gone down and come up, rather than potentially seeing the healthy states
+        that existed before the restart.
+        """
+        def _fail_restart(id_):
+            self.mds_daemons[id_].stop()
+            self.mon_manager.raw_cluster_cmd("mds", "fail", id_)
+            self.mds_daemons[id_].restart()
+
+        self._one_or_all(mds_id, _fail_restart)
+
+    def newfs(self, name='cephfs', create=True):
+        return Filesystem(self._ctx, name=name, create=create)
+
+    def status(self):
+        return FSStatus(self.mon_manager)
+
+    def delete_all_filesystems(self):
+        """
+        Remove all filesystems that exist, and any pools in use by them.
+        """
+        pools = json.loads(self.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json-pretty"))['pools']
+        pool_id_name = {}
+        for pool in pools:
+            pool_id_name[pool['pool']] = pool['pool_name']
+
+        # mark cluster down for each fs to prevent churn during deletion
+        status = self.status()
+        for fs in status.get_filesystems():
+            self.mon_manager.raw_cluster_cmd("fs", "set", fs['mdsmap']['fs_name'], "cluster_down", "true")
+
+        # get a new copy as actives may have since changed
+        status = self.status()
+        for fs in status.get_filesystems():
+            mdsmap = fs['mdsmap']
+            metadata_pool = pool_id_name[mdsmap['metadata_pool']]
+
+            for gid in mdsmap['up'].values():
+                self.mon_manager.raw_cluster_cmd('mds', 'fail', gid.__str__())
+
+            self.mon_manager.raw_cluster_cmd('fs', 'rm', mdsmap['fs_name'], '--yes-i-really-mean-it')
+            self.mon_manager.raw_cluster_cmd('osd', 'pool', 'delete',
+                                             metadata_pool, metadata_pool,
+                                             '--yes-i-really-really-mean-it')
+            for data_pool in mdsmap['data_pools']:
+                data_pool = pool_id_name[data_pool]
+                try:
+                    self.mon_manager.raw_cluster_cmd('osd', 'pool', 'delete',
+                                                     data_pool, data_pool,
+                                                     '--yes-i-really-really-mean-it')
+                except CommandFailedError as e:
+                    if e.exitstatus == 16: # EBUSY, this data pool is used
+                        pass               # by two metadata pools, let the 2nd
+                    else:                  # pass delete it
+                        raise
+
+    def get_standby_daemons(self):
+        return set([s['name'] for s in self.status().get_standbys()])
+
+    def get_mds_hostnames(self):
+        result = set()
+        for mds_id in self.mds_ids:
+            mds_remote = self.mon_manager.find_remote('mds', mds_id)
+            result.add(mds_remote.hostname)
+
+        return list(result)
+
+    def set_clients_block(self, blocked, mds_id=None):
+        """
+        Block (using iptables) client communications to this MDS.  Be careful: if
+        other services are running on this MDS, or other MDSs try to talk to this
+        MDS, their communications may also be blocked as collatoral damage.
+
+        :param mds_id: Optional ID of MDS to block, default to all
+        :return:
+        """
+        da_flag = "-A" if blocked else "-D"
+
+        def set_block(_mds_id):
+            remote = self.mon_manager.find_remote('mds', _mds_id)
+            status = self.status()
+
+            addr = status.get_mds_addr(_mds_id)
+            ip_str, port_str, inst_str = re.match("(.+):(.+)/(.+)", addr).groups()
+
+            remote.run(
+                args=["sudo", "iptables", da_flag, "OUTPUT", "-p", "tcp", "--sport", port_str, "-j", "REJECT", "-m",
+                      "comment", "--comment", "teuthology"])
+            remote.run(
+                args=["sudo", "iptables", da_flag, "INPUT", "-p", "tcp", "--dport", port_str, "-j", "REJECT", "-m",
+                      "comment", "--comment", "teuthology"])
+
+        self._one_or_all(mds_id, set_block, in_parallel=False)
+
+    def clear_firewall(self):
+        clear_firewall(self._ctx)
+
+    def get_mds_info(self, mds_id):
+        return FSStatus(self.mon_manager).get_mds(mds_id)
+
+    def is_full(self):
+        flags = json.loads(self.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json-pretty"))['flags']
+        return 'full' in flags
+
+    def is_pool_full(self, pool_name):
+        pools = json.loads(self.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json-pretty"))['pools']
+        for pool in pools:
+            if pool['pool_name'] == pool_name:
+                return 'full' in pool['flags_names'].split(",")
+
+        raise RuntimeError("Pool not found '{0}'".format(pool_name))
+
+class Filesystem(MDSCluster):
+    """
+    This object is for driving a CephFS filesystem.  The MDS daemons driven by
+    MDSCluster may be shared with other Filesystems.
+    """
+    def __init__(self, ctx, fscid=None, name=None, create=False,
+                 ec_profile=None):
+        super(Filesystem, self).__init__(ctx)
+
+        self.name = name
+        self.ec_profile = ec_profile
+        self.id = None
+        self.metadata_pool_name = None
+        self.metadata_overlay = False
+        self.data_pool_name = None
+        self.data_pools = None
+
+        client_list = list(misc.all_roles_of_type(self._ctx.cluster, 'client'))
+        self.client_id = client_list[0]
+        self.client_remote = list(misc.get_clients(ctx=ctx, roles=["client.{0}".format(self.client_id)]))[0][1]
+
+        if name is not None:
+            if fscid is not None:
+                raise RuntimeError("cannot specify fscid when creating fs")
+            if create and not self.legacy_configured():
+                self.create()
+        else:
+            if fscid is not None:
+                self.id = fscid
+                self.getinfo(refresh = True)
+
+        # Stash a reference to the first created filesystem on ctx, so
+        # that if someone drops to the interactive shell they can easily
+        # poke our methods.
+        if not hasattr(self._ctx, "filesystem"):
+            self._ctx.filesystem = self
+
+    def getinfo(self, refresh = False):
+        status = self.status()
+        if self.id is not None:
+            fsmap = status.get_fsmap(self.id)
+        elif self.name is not None:
+            fsmap = status.get_fsmap_byname(self.name)
+        else:
+            fss = [fs for fs in status.get_filesystems()]
+            if len(fss) == 1:
+                fsmap = fss[0]
+            elif len(fss) == 0:
+                raise RuntimeError("no file system available")
+            else:
+                raise RuntimeError("more than one file system available")
+        self.id = fsmap['id']
+        self.name = fsmap['mdsmap']['fs_name']
+        self.get_pool_names(status = status, refresh = refresh)
+        return status
+
+    def set_metadata_overlay(self, overlay):
+        if self.id is not None:
+            raise RuntimeError("cannot specify fscid when configuring overlay")
+        self.metadata_overlay = overlay
+
+    def deactivate(self, rank):
+        if rank < 0:
+            raise RuntimeError("invalid rank")
+        elif rank == 0:
+            raise RuntimeError("cannot deactivate rank 0")
+        self.mon_manager.raw_cluster_cmd("mds", "deactivate", "%d:%d" % (self.id, rank))
+
+    def set_max_mds(self, max_mds):
+        self.mon_manager.raw_cluster_cmd("fs", "set", self.name, "max_mds", "%d" % max_mds)
+
+    def set_allow_dirfrags(self, yes):
+        self.mon_manager.raw_cluster_cmd("fs", "set", self.name, "allow_dirfrags", str(yes).lower(), '--yes-i-really-mean-it')
+
+    def get_pgs_per_fs_pool(self):
+        """
+        Calculate how many PGs to use when creating a pool, in order to avoid raising any
+        health warnings about mon_pg_warn_min_per_osd
+
+        :return: an integer number of PGs
+        """
+        pg_warn_min_per_osd = int(self.get_config('mon_pg_warn_min_per_osd'))
+        osd_count = len(list(misc.all_roles_of_type(self._ctx.cluster, 'osd')))
+        return pg_warn_min_per_osd * osd_count
+
+    def create(self):
+        if self.name is None:
+            self.name = "cephfs"
+        if self.metadata_pool_name is None:
+            self.metadata_pool_name = "{0}_metadata".format(self.name)
+        if self.data_pool_name is None:
+            data_pool_name = "{0}_data".format(self.name)
+        else:
+            data_pool_name = self.data_pool_name
+
+        log.info("Creating filesystem '{0}'".format(self.name))
+
+        pgs_per_fs_pool = self.get_pgs_per_fs_pool()
+
+        self.mon_manager.raw_cluster_cmd('osd', 'pool', 'create',
+                                         self.metadata_pool_name, pgs_per_fs_pool.__str__())
+        if self.metadata_overlay:
+            self.mon_manager.raw_cluster_cmd('fs', 'new',
+                                             self.name, self.metadata_pool_name, data_pool_name,
+                                             '--allow-dangerous-metadata-overlay')
+        else:
+            if self.ec_profile:
+                log.info("EC profile is %s", self.ec_profile)
+                cmd = ['osd', 'erasure-code-profile', 'set', data_pool_name]
+                cmd.extend(self.ec_profile)
+                self.mon_manager.raw_cluster_cmd(*cmd)
+                self.mon_manager.raw_cluster_cmd(
+                    'osd', 'pool', 'create',
+                    data_pool_name, pgs_per_fs_pool.__str__(), 'erasure',
+                    data_pool_name)
+                self.mon_manager.raw_cluster_cmd(
+                    'osd', 'pool', 'set',
+                    data_pool_name, 'allow_ec_overwrites', 'true')
+            else:
+                self.mon_manager.raw_cluster_cmd(
+                    'osd', 'pool', 'create',
+                    data_pool_name, pgs_per_fs_pool.__str__())
+            self.mon_manager.raw_cluster_cmd('fs', 'new',
+                                             self.name, self.metadata_pool_name, data_pool_name)
+        self.check_pool_application(self.metadata_pool_name)
+        self.check_pool_application(data_pool_name)
+        # Turn off spurious standby count warnings from modifying max_mds in tests.
+        try:
+            self.mon_manager.raw_cluster_cmd('fs', 'set', self.name, 'standby_count_wanted', '0')
+        except CommandFailedError as e:
+            if e.exitstatus == 22:
+                # standby_count_wanted not available prior to luminous (upgrade tests would fail otherwise)
+                pass
+            else:
+                raise
+
+        self.getinfo(refresh = True)
+
+        
+    def check_pool_application(self, pool_name):
+        osd_map = self.mon_manager.get_osd_dump_json()
+        for pool in osd_map['pools']:
+            if pool['pool_name'] == pool_name:
+                if "application_metadata" in pool:
+                    if not "cephfs" in pool['application_metadata']:
+                        raise RuntimeError("Pool %p does not name cephfs as application!".\
+                                           format(pool_name))
+        
+
+    def __del__(self):
+        if getattr(self._ctx, "filesystem", None) == self:
+            delattr(self._ctx, "filesystem")
+
+    def exists(self):
+        """
+        Whether a filesystem exists in the mon's filesystem list
+        """
+        fs_list = json.loads(self.mon_manager.raw_cluster_cmd('fs', 'ls', '--format=json-pretty'))
+        return self.name in [fs['name'] for fs in fs_list]
+
+    def legacy_configured(self):
+        """
+        Check if a legacy (i.e. pre "fs new") filesystem configuration is present.  If this is
+        the case, the caller should avoid using Filesystem.create
+        """
+        try:
+            out_text = self.mon_manager.raw_cluster_cmd('--format=json-pretty', 'osd', 'lspools')
+            pools = json.loads(out_text)
+            metadata_pool_exists = 'metadata' in [p['poolname'] for p in pools]
+            if metadata_pool_exists:
+                self.metadata_pool_name = 'metadata'
+        except CommandFailedError as e:
+            # For use in upgrade tests, Ceph cuttlefish and earlier don't support
+            # structured output (--format) from the CLI.
+            if e.exitstatus == 22:
+                metadata_pool_exists = True
+            else:
+                raise
+
+        return metadata_pool_exists
+
+    def _df(self):
+        return json.loads(self.mon_manager.raw_cluster_cmd("df", "--format=json-pretty"))
+
+    def get_mds_map(self):
+        return self.status().get_fsmap(self.id)['mdsmap']
+
+    def add_data_pool(self, name):
+        self.mon_manager.raw_cluster_cmd('osd', 'pool', 'create', name, self.get_pgs_per_fs_pool().__str__())
+        self.mon_manager.raw_cluster_cmd('fs', 'add_data_pool', self.name, name)
+        self.get_pool_names(refresh = True)
+        for poolid, fs_name in self.data_pools.items():
+            if name == fs_name:
+                return poolid
+        raise RuntimeError("could not get just created pool '{0}'".format(name))
+
+    def get_pool_names(self, refresh = False, status = None):
+        if refresh or self.metadata_pool_name is None or self.data_pools is None:
+            if status is None:
+                status = self.status()
+            fsmap = status.get_fsmap(self.id)
+
+            osd_map = self.mon_manager.get_osd_dump_json()
+            id_to_name = {}
+            for p in osd_map['pools']:
+                id_to_name[p['pool']] = p['pool_name']
+
+            self.metadata_pool_name = id_to_name[fsmap['mdsmap']['metadata_pool']]
+            self.data_pools = {}
+            for data_pool in fsmap['mdsmap']['data_pools']:
+                self.data_pools[data_pool] = id_to_name[data_pool]
+
+    def get_data_pool_name(self, refresh = False):
+        if refresh or self.data_pools is None:
+            self.get_pool_names(refresh = True)
+        assert(len(self.data_pools) == 1)
+        return self.data_pools.values()[0]
+
+    def get_data_pool_id(self, refresh = False):
+        """
+        Don't call this if you have multiple data pools
+        :return: integer
+        """
+        if refresh or self.data_pools is None:
+            self.get_pool_names(refresh = True)
+        assert(len(self.data_pools) == 1)
+        return self.data_pools.keys()[0]
+
+    def get_data_pool_names(self, refresh = False):
+        if refresh or self.data_pools is None:
+            self.get_pool_names(refresh = True)
+        return self.data_pools.values()
+
+    def get_metadata_pool_name(self):
+        return self.metadata_pool_name
+
+    def set_data_pool_name(self, name):
+        if self.id is not None:
+            raise RuntimeError("can't set filesystem name if its fscid is set")
+        self.data_pool_name = name
+
+    def get_namespace_id(self):
+        return self.id
+
+    def get_pool_df(self, pool_name):
+        """
+        Return a dict like:
+        {u'bytes_used': 0, u'max_avail': 83848701, u'objects': 0, u'kb_used': 0}
+        """
+        for pool_df in self._df()['pools']:
+            if pool_df['name'] == pool_name:
+                return pool_df['stats']
+
+        raise RuntimeError("Pool name '{0}' not found".format(pool_name))
+
+    def get_usage(self):
+        return self._df()['stats']['total_used_bytes']
+
+    def are_daemons_healthy(self):
+        """
+        Return true if all daemons are in one of active, standby, standby-replay, and
+        at least max_mds daemons are in 'active'.
+
+        Unlike most of Filesystem, this function is tolerant of new-style `fs`
+        commands being missing, because we are part of the ceph installation
+        process during upgrade suites, so must fall back to old style commands
+        when we get an EINVAL on a new style command.
+
+        :return:
+        """
+
+        active_count = 0
+        try:
+            mds_map = self.get_mds_map()
+        except CommandFailedError as cfe:
+            # Old version, fall back to non-multi-fs commands
+            if cfe.exitstatus == errno.EINVAL:
+                mds_map = json.loads(
+                        self.mon_manager.raw_cluster_cmd('mds', 'dump', '--format=json'))
+            else:
+                raise
+
+        log.info("are_daemons_healthy: mds map: {0}".format(mds_map))
+
+        for mds_id, mds_status in mds_map['info'].items():
+            if mds_status['state'] not in ["up:active", "up:standby", "up:standby-replay"]:
+                log.warning("Unhealthy mds state {0}:{1}".format(mds_id, mds_status['state']))
+                return False
+            elif mds_status['state'] == 'up:active':
+                active_count += 1
+
+        log.info("are_daemons_healthy: {0}/{1}".format(
+            active_count, mds_map['max_mds']
+        ))
+
+        if active_count >= mds_map['max_mds']:
+            # The MDSMap says these guys are active, but let's check they really are
+            for mds_id, mds_status in mds_map['info'].items():
+                if mds_status['state'] == 'up:active':
+                    try:
+                        daemon_status = self.mds_asok(["status"], mds_id=mds_status['name'])
+                    except CommandFailedError as cfe:
+                        if cfe.exitstatus == errno.EINVAL:
+                            # Old version, can't do this check
+                            continue
+                        else:
+                            # MDS not even running
+                            return False
+
+                    if daemon_status['state'] != 'up:active':
+                        # MDS hasn't taken the latest map yet
+                        return False
+
+            return True
+        else:
+            return False
+
+    def get_daemon_names(self, state=None):
+        """
+        Return MDS daemon names of those daemons in the given state
+        :param state:
+        :return:
+        """
+        status = self.get_mds_map()
+        result = []
+        for mds_status in sorted(status['info'].values(), lambda a, b: cmp(a['rank'], b['rank'])):
+            if mds_status['state'] == state or state is None:
+                result.append(mds_status['name'])
+
+        return result
+
+    def get_active_names(self):
+        """
+        Return MDS daemon names of those daemons holding ranks
+        in state up:active
+
+        :return: list of strings like ['a', 'b'], sorted by rank
+        """
+        return self.get_daemon_names("up:active")
+
+    def get_all_mds_rank(self):
+        status = self.get_mds_map()
+        result = []
+        for mds_status in sorted(status['info'].values(), lambda a, b: cmp(a['rank'], b['rank'])):
+            if mds_status['rank'] != -1 and mds_status['state'] != 'up:standby-replay':
+                result.append(mds_status['rank'])
+
+        return result
+
+    def get_rank_names(self):
+        """
+        Return MDS daemon names of those daemons holding a rank,
+        sorted by rank.  This includes e.g. up:replay/reconnect
+        as well as active, but does not include standby or
+        standby-replay.
+        """
+        status = self.get_mds_map()
+        result = []
+        for mds_status in sorted(status['info'].values(), lambda a, b: cmp(a['rank'], b['rank'])):
+            if mds_status['rank'] != -1 and mds_status['state'] != 'up:standby-replay':
+                result.append(mds_status['name'])
+
+        return result
+
+    def wait_for_daemons(self, timeout=None):
+        """
+        Wait until all daemons are healthy
+        :return:
+        """
+
+        if timeout is None:
+            timeout = DAEMON_WAIT_TIMEOUT
+
+        elapsed = 0
+        while True:
+            if self.are_daemons_healthy():
+                return
+            else:
+                time.sleep(1)
+                elapsed += 1
+
+            if elapsed > timeout:
+                raise RuntimeError("Timed out waiting for MDS daemons to become healthy")
+
+    def get_lone_mds_id(self):
+        """
+        Get a single MDS ID: the only one if there is only one
+        configured, else the only one currently holding a rank,
+        else raise an error.
+        """
+        if len(self.mds_ids) != 1:
+            alive = self.get_rank_names()
+            if len(alive) == 1:
+                return alive[0]
+            else:
+                raise ValueError("Explicit MDS argument required when multiple MDSs in use")
+        else:
+            return self.mds_ids[0]
+
+    def recreate(self):
+        log.info("Creating new filesystem")
+        self.delete_all_filesystems()
+        self.id = None
+        self.create()
+
+    def put_metadata_object_raw(self, object_id, infile):
+        """
+        Save an object to the metadata pool
+        """
+        temp_bin_path = infile
+        self.client_remote.run(args=[
+            'sudo', os.path.join(self._prefix, 'rados'), '-p', self.metadata_pool_name, 'put', object_id, temp_bin_path
+        ])
+
+    def get_metadata_object_raw(self, object_id):
+        """
+        Retrieve an object from the metadata pool and store it in a file.
+        """
+        temp_bin_path = '/tmp/' + object_id + '.bin'
+
+        self.client_remote.run(args=[
+            'sudo', os.path.join(self._prefix, 'rados'), '-p', self.metadata_pool_name, 'get', object_id, temp_bin_path
+        ])
+
+        return temp_bin_path
+
+    def get_metadata_object(self, object_type, object_id):
+        """
+        Retrieve an object from the metadata pool, pass it through
+        ceph-dencoder to dump it to JSON, and return the decoded object.
+        """
+        temp_bin_path = '/tmp/out.bin'
+
+        self.client_remote.run(args=[
+            'sudo', os.path.join(self._prefix, 'rados'), '-p', self.metadata_pool_name, 'get', object_id, temp_bin_path
+        ])
+
+        stdout = StringIO()
+        self.client_remote.run(args=[
+            'sudo', os.path.join(self._prefix, 'ceph-dencoder'), 'type', object_type, 'import', temp_bin_path, 'decode', 'dump_json'
+        ], stdout=stdout)
+        dump_json = stdout.getvalue().strip()
+        try:
+            dump = json.loads(dump_json)
+        except (TypeError, ValueError):
+            log.error("Failed to decode JSON: '{0}'".format(dump_json))
+            raise
+
+        return dump
+
+    def get_journal_version(self):
+        """
+        Read the JournalPointer and Journal::Header objects to learn the version of
+        encoding in use.
+        """
+        journal_pointer_object = '400.00000000'
+        journal_pointer_dump = self.get_metadata_object("JournalPointer", journal_pointer_object)
+        journal_ino = journal_pointer_dump['journal_pointer']['front']
+
+        journal_header_object = "{0:x}.00000000".format(journal_ino)
+        journal_header_dump = self.get_metadata_object('Journaler::Header', journal_header_object)
+
+        version = journal_header_dump['journal_header']['stream_format']
+        log.info("Read journal version {0}".format(version))
+
+        return version
+
+    def mds_asok(self, command, mds_id=None):
+        if mds_id is None:
+            mds_id = self.get_lone_mds_id()
+
+        return self.json_asok(command, 'mds', mds_id)
+
+    def read_cache(self, path, depth=None):
+        cmd = ["dump", "tree", path]
+        if depth is not None:
+            cmd.append(depth.__str__())
+        result = self.mds_asok(cmd)
+        if len(result) == 0:
+            raise RuntimeError("Path not found in cache: {0}".format(path))
+
+        return result
+
+    def wait_for_state(self, goal_state, reject=None, timeout=None, mds_id=None, rank=None):
+        """
+        Block until the MDS reaches a particular state, or a failure condition
+        is met.
+
+        When there are multiple MDSs, succeed when exaclty one MDS is in the
+        goal state, or fail when any MDS is in the reject state.
+
+        :param goal_state: Return once the MDS is in this state
+        :param reject: Fail if the MDS enters this state before the goal state
+        :param timeout: Fail if this many seconds pass before reaching goal
+        :return: number of seconds waited, rounded down to integer
+        """
+
+        started_at = time.time()
+        while True:
+            status = self.status()
+            if rank is not None:
+                mds_info = status.get_rank(self.id, rank)
+                current_state = mds_info['state'] if mds_info else None
+                log.info("Looked up MDS state for mds.{0}: {1}".format(rank, current_state))
+            elif mds_id is not None:
+                # mds_info is None if no daemon with this ID exists in the map
+                mds_info = status.get_mds(mds_id)
+                current_state = mds_info['state'] if mds_info else None
+                log.info("Looked up MDS state for {0}: {1}".format(mds_id, current_state))
+            else:
+                # In general, look for a single MDS
+                states = [m['state'] for m in status.get_ranks(self.id)]
+                if [s for s in states if s == goal_state] == [goal_state]:
+                    current_state = goal_state
+                elif reject in states:
+                    current_state = reject
+                else:
+                    current_state = None
+                log.info("mapped states {0} to {1}".format(states, current_state))
+
+            elapsed = time.time() - started_at
+            if current_state == goal_state:
+                log.info("reached state '{0}' in {1}s".format(current_state, elapsed))
+                return elapsed
+            elif reject is not None and current_state == reject:
+                raise RuntimeError("MDS in reject state {0}".format(current_state))
+            elif timeout is not None and elapsed > timeout:
+                log.error("MDS status at timeout: {0}".format(status.get_fsmap(self.id)))
+                raise RuntimeError(
+                    "Reached timeout after {0} seconds waiting for state {1}, while in state {2}".format(
+                        elapsed, goal_state, current_state
+                    ))
+            else:
+                time.sleep(1)
+
+    def _read_data_xattr(self, ino_no, xattr_name, type, pool):
+        mds_id = self.mds_ids[0]
+        remote = self.mds_daemons[mds_id].remote
+        if pool is None:
+            pool = self.get_data_pool_name()
+
+        obj_name = "{0:x}.00000000".format(ino_no)
+
+        args = [
+            os.path.join(self._prefix, "rados"), "-p", pool, "getxattr", obj_name, xattr_name
+        ]
+        try:
+            proc = remote.run(
+                args=args,
+                stdout=StringIO())
+        except CommandFailedError as e:
+            log.error(e.__str__())
+            raise ObjectNotFound(obj_name)
+
+        data = proc.stdout.getvalue()
+
+        p = remote.run(
+            args=[os.path.join(self._prefix, "ceph-dencoder"), "type", type, "import", "-", "decode", "dump_json"],
+            stdout=StringIO(),
+            stdin=data
+        )
+
+        return json.loads(p.stdout.getvalue().strip())
+
+    def _write_data_xattr(self, ino_no, xattr_name, data, pool=None):
+        """
+        Write to an xattr of the 0th data object of an inode.  Will
+        succeed whether the object and/or xattr already exist or not.
+
+        :param ino_no: integer inode number
+        :param xattr_name: string name of the xattr
+        :param data: byte array data to write to the xattr
+        :param pool: name of data pool or None to use primary data pool
+        :return: None
+        """
+        remote = self.mds_daemons[self.mds_ids[0]].remote
+        if pool is None:
+            pool = self.get_data_pool_name()
+
+        obj_name = "{0:x}.00000000".format(ino_no)
+        args = [
+            os.path.join(self._prefix, "rados"), "-p", pool, "setxattr",
+            obj_name, xattr_name, data
+        ]
+        remote.run(
+            args=args,
+            stdout=StringIO())
+
+    def read_backtrace(self, ino_no, pool=None):
+        """
+        Read the backtrace from the data pool, return a dict in the format
+        given by inode_backtrace_t::dump, which is something like:
+
+        ::
+
+            rados -p cephfs_data getxattr 10000000002.00000000 parent > out.bin
+            ceph-dencoder type inode_backtrace_t import out.bin decode dump_json
+
+            { "ino": 1099511627778,
+              "ancestors": [
+                    { "dirino": 1,
+                      "dname": "blah",
+                      "version": 11}],
+              "pool": 1,
+              "old_pools": []}
+
+        :param pool: name of pool to read backtrace from.  If omitted, FS must have only
+                     one data pool and that will be used.
+        """
+        return self._read_data_xattr(ino_no, "parent", "inode_backtrace_t", pool)
+
+    def read_layout(self, ino_no, pool=None):
+        """
+        Read 'layout' xattr of an inode and parse the result, returning a dict like:
+        ::
+            {
+                "stripe_unit": 4194304,
+                "stripe_count": 1,
+                "object_size": 4194304,
+                "pool_id": 1,
+                "pool_ns": "",
+            }
+
+        :param pool: name of pool to read backtrace from.  If omitted, FS must have only
+                     one data pool and that will be used.
+        """
+        return self._read_data_xattr(ino_no, "layout", "file_layout_t", pool)
+
+    def _enumerate_data_objects(self, ino, size):
+        """
+        Get the list of expected data objects for a range, and the list of objects
+        that really exist.
+
+        :return a tuple of two lists of strings (expected, actual)
+        """
+        stripe_size = 1024 * 1024 * 4
+
+        size = max(stripe_size, size)
+
+        want_objects = [
+            "{0:x}.{1:08x}".format(ino, n)
+            for n in range(0, ((size - 1) / stripe_size) + 1)
+        ]
+
+        exist_objects = self.rados(["ls"], pool=self.get_data_pool_name()).split("\n")
+
+        return want_objects, exist_objects
+
+    def data_objects_present(self, ino, size):
+        """
+        Check that *all* the expected data objects for an inode are present in the data pool
+        """
+
+        want_objects, exist_objects = self._enumerate_data_objects(ino, size)
+        missing = set(want_objects) - set(exist_objects)
+
+        if missing:
+            log.info("Objects missing (ino {0}, size {1}): {2}".format(
+                ino, size, missing
+            ))
+            return False
+        else:
+            log.info("All objects for ino {0} size {1} found".format(ino, size))
+            return True
+
+    def data_objects_absent(self, ino, size):
+        want_objects, exist_objects = self._enumerate_data_objects(ino, size)
+        present = set(want_objects) & set(exist_objects)
+
+        if present:
+            log.info("Objects not absent (ino {0}, size {1}): {2}".format(
+                ino, size, present
+            ))
+            return False
+        else:
+            log.info("All objects for ino {0} size {1} are absent".format(ino, size))
+            return True
+
+    def dirfrag_exists(self, ino, frag):
+        try:
+            self.rados(["stat", "{0:x}.{1:08x}".format(ino, frag)])
+        except CommandFailedError as e:
+            return False
+        else:
+            return True
+
+    def rados(self, args, pool=None, namespace=None, stdin_data=None):
+        """
+        Call into the `rados` CLI from an MDS
+        """
+
+        if pool is None:
+            pool = self.get_metadata_pool_name()
+
+        # Doesn't matter which MDS we use to run rados commands, they all
+        # have access to the pools
+        mds_id = self.mds_ids[0]
+        remote = self.mds_daemons[mds_id].remote
+
+        # NB we could alternatively use librados pybindings for this, but it's a one-liner
+        # using the `rados` CLI
+        args = ([os.path.join(self._prefix, "rados"), "-p", pool] +
+                (["--namespace", namespace] if namespace else []) +
+                args)
+        p = remote.run(
+            args=args,
+            stdin=stdin_data,
+            stdout=StringIO())
+        return p.stdout.getvalue().strip()
+
+    def list_dirfrag(self, dir_ino):
+        """
+        Read the named object and return the list of omap keys
+
+        :return a list of 0 or more strings
+        """
+
+        dirfrag_obj_name = "{0:x}.00000000".format(dir_ino)
+
+        try:
+            key_list_str = self.rados(["listomapkeys", dirfrag_obj_name])
+        except CommandFailedError as e:
+            log.error(e.__str__())
+            raise ObjectNotFound(dirfrag_obj_name)
+
+        return key_list_str.split("\n") if key_list_str else []
+
+    def erase_metadata_objects(self, prefix):
+        """
+        For all objects in the metadata pool matching the prefix,
+        erase them.
+
+        This O(N) with the number of objects in the pool, so only suitable
+        for use on toy test filesystems.
+        """
+        all_objects = self.rados(["ls"]).split("\n")
+        matching_objects = [o for o in all_objects if o.startswith(prefix)]
+        for o in matching_objects:
+            self.rados(["rm", o])
+
+    def erase_mds_objects(self, rank):
+        """
+        Erase all the per-MDS objects for a particular rank.  This includes
+        inotable, sessiontable, journal
+        """
+
+        def obj_prefix(multiplier):
+            """
+            MDS object naming conventions like rank 1's
+            journal is at 201.***
+            """
+            return "%x." % (multiplier * 0x100 + rank)
+
+        # MDS_INO_LOG_OFFSET
+        self.erase_metadata_objects(obj_prefix(2))
+        # MDS_INO_LOG_BACKUP_OFFSET
+        self.erase_metadata_objects(obj_prefix(3))
+        # MDS_INO_LOG_POINTER_OFFSET
+        self.erase_metadata_objects(obj_prefix(4))
+        # MDSTables & SessionMap
+        self.erase_metadata_objects("mds{rank:d}_".format(rank=rank))
+
+    @property
+    def _prefix(self):
+        """
+        Override this to set a different
+        """
+        return ""
+
+    def _run_tool(self, tool, args, rank=None, quiet=False):
+        # Tests frequently have [client] configuration that jacks up
+        # the objecter log level (unlikely to be interesting here)
+        # and does not set the mds log level (very interesting here)
+        if quiet:
+            base_args = [os.path.join(self._prefix, tool), '--debug-mds=1', '--debug-objecter=1']
+        else:
+            base_args = [os.path.join(self._prefix, tool), '--debug-mds=4', '--debug-objecter=1']
+
+        if rank is not None:
+            base_args.extend(["--rank", "%d" % rank])
+
+        t1 = datetime.datetime.now()
+        r = self.tool_remote.run(
+            args=base_args + args,
+            stdout=StringIO()).stdout.getvalue().strip()
+        duration = datetime.datetime.now() - t1
+        log.info("Ran {0} in time {1}, result:\n{2}".format(
+            base_args + args, duration, r
+        ))
+        return r
+
+    @property
+    def tool_remote(self):
+        """
+        An arbitrary remote to use when invoking recovery tools.  Use an MDS host because
+        it'll definitely have keys with perms to access cephfs metadata pool.  This is public
+        so that tests can use this remote to go get locally written output files from the tools.
+        """
+        mds_id = self.mds_ids[0]
+        return self.mds_daemons[mds_id].remote
+
+    def journal_tool(self, args, rank=None, quiet=False):
+        """
+        Invoke cephfs-journal-tool with the passed arguments, and return its stdout
+        """
+        return self._run_tool("cephfs-journal-tool", args, rank, quiet)
+
+    def table_tool(self, args, quiet=False):
+        """
+        Invoke cephfs-table-tool with the passed arguments, and return its stdout
+        """
+        return self._run_tool("cephfs-table-tool", args, None, quiet)
+
+    def data_scan(self, args, quiet=False, worker_count=1):
+        """
+        Invoke cephfs-data-scan with the passed arguments, and return its stdout
+
+        :param worker_count: if greater than 1, multiple workers will be run
+                             in parallel and the return value will be None
+        """
+
+        workers = []
+
+        for n in range(0, worker_count):
+            if worker_count > 1:
+                # data-scan args first token is a command, followed by args to it.
+                # insert worker arguments after the command.
+                cmd = args[0]
+                worker_args = [cmd] + ["--worker_n", n.__str__(), "--worker_m", worker_count.__str__()] + args[1:]
+            else:
+                worker_args = args
+
+            workers.append(Greenlet.spawn(lambda wargs=worker_args:
+                                          self._run_tool("cephfs-data-scan", wargs, None, quiet)))
+
+        for w in workers:
+            w.get()
+
+        if worker_count == 1:
+            return workers[0].value
+        else:
+            return None
diff --git a/src/ceph/qa/tasks/cephfs/fuse_mount.py b/src/ceph/qa/tasks/cephfs/fuse_mount.py
new file mode 100644
index 0000000..8d8410c
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/fuse_mount.py
@@ -0,0 +1,428 @@
+
+from StringIO import StringIO
+import json
+import time
+import logging
+from textwrap import dedent
+
+from teuthology import misc
+from teuthology.contextutil import MaxWhileTries
+from teuthology.orchestra import run
+from teuthology.orchestra.run import CommandFailedError
+from .mount import CephFSMount
+
+log = logging.getLogger(__name__)
+
+
+class FuseMount(CephFSMount):
+    def __init__(self, client_config, test_dir, client_id, client_remote):
+        super(FuseMount, self).__init__(test_dir, client_id, client_remote)
+
+        self.client_config = client_config if client_config else {}
+        self.fuse_daemon = None
+        self._fuse_conn = None
+
+    def mount(self, mount_path=None, mount_fs_name=None):
+        try:
+            return self._mount(mount_path, mount_fs_name)
+        except RuntimeError:
+            # Catch exceptions by the mount() logic (i.e. not remote command
+            # failures) and ensure the mount is not left half-up.
+            # Otherwise we might leave a zombie mount point that causes
+            # anyone traversing cephtest/ to get hung up on.
+            log.warn("Trying to clean up after failed mount")
+            self.umount_wait(force=True)
+            raise
+
+    def _mount(self, mount_path, mount_fs_name):
+        log.info("Client client.%s config is %s" % (self.client_id, self.client_config))
+
+        daemon_signal = 'kill'
+        if self.client_config.get('coverage') or self.client_config.get('valgrind') is not None:
+            daemon_signal = 'term'
+
+        log.info('Mounting ceph-fuse client.{id} at {remote} {mnt}...'.format(
+            id=self.client_id, remote=self.client_remote, mnt=self.mountpoint))
+
+        self.client_remote.run(
+            args=[
+                'mkdir',
+                '--',
+                self.mountpoint,
+            ],
+        )
+
+        run_cmd = [
+            'sudo',
+            'adjust-ulimits',
+            'ceph-coverage',
+            '{tdir}/archive/coverage'.format(tdir=self.test_dir),
+            'daemon-helper',
+            daemon_signal,
+        ]
+
+        fuse_cmd = ['ceph-fuse', "-f"]
+
+        if mount_path is not None:
+            fuse_cmd += ["--client_mountpoint={0}".format(mount_path)]
+
+        if mount_fs_name is not None:
+            fuse_cmd += ["--client_mds_namespace={0}".format(mount_fs_name)]
+
+        fuse_cmd += [
+            '--name', 'client.{id}'.format(id=self.client_id),
+            # TODO ceph-fuse doesn't understand dash dash '--',
+            self.mountpoint,
+        ]
+
+        if self.client_config.get('valgrind') is not None:
+            run_cmd = misc.get_valgrind_args(
+                self.test_dir,
+                'client.{id}'.format(id=self.client_id),
+                run_cmd,
+                self.client_config.get('valgrind'),
+            )
+
+        run_cmd.extend(fuse_cmd)
+
+        def list_connections():
+            self.client_remote.run(
+                args=["sudo", "mount", "-t", "fusectl", "/sys/fs/fuse/connections", "/sys/fs/fuse/connections"],
+                check_status=False
+            )
+            p = self.client_remote.run(
+                args=["ls", "/sys/fs/fuse/connections"],
+                stdout=StringIO(),
+                check_status=False
+            )
+            if p.exitstatus != 0:
+                return []
+
+            ls_str = p.stdout.getvalue().strip()
+            if ls_str:
+                return [int(n) for n in ls_str.split("\n")]
+            else:
+                return []
+
+        # Before starting ceph-fuse process, note the contents of
+        # /sys/fs/fuse/connections
+        pre_mount_conns = list_connections()
+        log.info("Pre-mount connections: {0}".format(pre_mount_conns))
+
+        proc = self.client_remote.run(
+            args=run_cmd,
+            logger=log.getChild('ceph-fuse.{id}'.format(id=self.client_id)),
+            stdin=run.PIPE,
+            wait=False,
+        )
+        self.fuse_daemon = proc
+
+        # Wait for the connection reference to appear in /sys
+        mount_wait = self.client_config.get('mount_wait', 0)
+        if mount_wait > 0:
+            log.info("Fuse mount waits {0} seconds before checking /sys/".format(mount_wait))
+            time.sleep(mount_wait)            
+        timeout = int(self.client_config.get('mount_timeout', 30))
+        waited = 0
+
+        post_mount_conns = list_connections()
+        while len(post_mount_conns) <= len(pre_mount_conns):
+            if self.fuse_daemon.finished:
+                # Did mount fail?  Raise the CommandFailedError instead of
+                # hitting the "failed to populate /sys/" timeout
+                self.fuse_daemon.wait()
+            time.sleep(1)
+            waited += 1
+            if waited > timeout:
+                raise RuntimeError("Fuse mount failed to populate /sys/ after {0} seconds".format(
+                    waited
+                ))
+            else:
+                post_mount_conns = list_connections()
+
+        log.info("Post-mount connections: {0}".format(post_mount_conns))
+
+        # Record our fuse connection number so that we can use it when
+        # forcing an unmount
+        new_conns = list(set(post_mount_conns) - set(pre_mount_conns))
+        if len(new_conns) == 0:
+            raise RuntimeError("New fuse connection directory not found ({0})".format(new_conns))
+        elif len(new_conns) > 1:
+            raise RuntimeError("Unexpectedly numerous fuse connections {0}".format(new_conns))
+        else:
+            self._fuse_conn = new_conns[0]
+
+    def is_mounted(self):
+        proc = self.client_remote.run(
+            args=[
+                'stat',
+                '--file-system',
+                '--printf=%T\n',
+                '--',
+                self.mountpoint,
+            ],
+            stdout=StringIO(),
+            stderr=StringIO(),
+            wait=False
+        )
+        try:
+            proc.wait()
+        except CommandFailedError:
+            if ("endpoint is not connected" in proc.stderr.getvalue()
+            or "Software caused connection abort" in proc.stderr.getvalue()):
+                # This happens is fuse is killed without unmount
+                log.warn("Found stale moutn point at {0}".format(self.mountpoint))
+                return True
+            else:
+                # This happens if the mount directory doesn't exist
+                log.info('mount point does not exist: %s', self.mountpoint)
+                return False
+
+        fstype = proc.stdout.getvalue().rstrip('\n')
+        if fstype == 'fuseblk':
+            log.info('ceph-fuse is mounted on %s', self.mountpoint)
+            return True
+        else:
+            log.debug('ceph-fuse not mounted, got fs type {fstype!r}'.format(
+                fstype=fstype))
+            return False
+
+    def wait_until_mounted(self):
+        """
+        Check to make sure that fuse is mounted on mountpoint.  If not,
+        sleep for 5 seconds and check again.
+        """
+
+        while not self.is_mounted():
+            # Even if it's not mounted, it should at least
+            # be running: catch simple failures where it has terminated.
+            assert not self.fuse_daemon.poll()
+
+            time.sleep(5)
+
+        # Now that we're mounted, set permissions so that the rest of the test will have
+        # unrestricted access to the filesystem mount.
+        self.client_remote.run(
+            args=['sudo', 'chmod', '1777', self.mountpoint])
+
+    def _mountpoint_exists(self):
+        return self.client_remote.run(args=["ls", "-d", self.mountpoint], check_status=False).exitstatus == 0
+
+    def umount(self):
+        try:
+            log.info('Running fusermount -u on {name}...'.format(name=self.client_remote.name))
+            self.client_remote.run(
+                args=[
+                    'sudo',
+                    'fusermount',
+                    '-u',
+                    self.mountpoint,
+                ],
+            )
+        except run.CommandFailedError:
+            log.info('Failed to unmount ceph-fuse on {name}, aborting...'.format(name=self.client_remote.name))
+
+            self.client_remote.run(args=[
+                'sudo',
+                run.Raw('PATH=/usr/sbin:$PATH'),
+                'lsof',
+                run.Raw(';'),
+                'ps',
+                'auxf',
+            ])
+
+            # abort the fuse mount, killing all hung processes
+            if self._fuse_conn:
+                self.run_python(dedent("""
+                import os
+                path = "/sys/fs/fuse/connections/{0}/abort"
+                if os.path.exists(path):
+                    open(path, "w").write("1")
+                """).format(self._fuse_conn))
+                self._fuse_conn = None
+
+            stderr = StringIO()
+            try:
+                # make sure its unmounted
+                self.client_remote.run(
+                    args=[
+                        'sudo',
+                        'umount',
+                        '-l',
+                        '-f',
+                        self.mountpoint,
+                    ],
+                    stderr=stderr
+                )
+            except CommandFailedError:
+                if self.is_mounted():
+                    raise
+
+        assert not self.is_mounted()
+        self._fuse_conn = None
+
+    def umount_wait(self, force=False, require_clean=False):
+        """
+        :param force: Complete cleanly even if the MDS is offline
+        """
+        if force:
+            assert not require_clean  # mutually exclusive
+
+            # When we expect to be forcing, kill the ceph-fuse process directly.
+            # This should avoid hitting the more aggressive fallback killing
+            # in umount() which can affect other mounts too.
+            self.fuse_daemon.stdin.close()
+
+            # However, we will still hit the aggressive wait if there is an ongoing
+            # mount -o remount (especially if the remount is stuck because MDSs
+            # are unavailable)
+
+        self.umount()
+
+        try:
+            if self.fuse_daemon:
+                # Permit a timeout, so that we do not block forever
+                run.wait([self.fuse_daemon], 900)
+        except MaxWhileTries:
+            log.error("process failed to terminate after unmount.  This probably"
+                      "indicates a bug within ceph-fuse.")
+            raise
+        except CommandFailedError:
+            if require_clean:
+                raise
+
+        self.cleanup()
+
+    def cleanup(self):
+        """
+        Remove the mount point.
+
+        Prerequisite: the client is not mounted.
+        """
+        stderr = StringIO()
+        try:
+            self.client_remote.run(
+                args=[
+                    'rmdir',
+                    '--',
+                    self.mountpoint,
+                ],
+                stderr=stderr
+            )
+        except CommandFailedError:
+            if "No such file or directory" in stderr.getvalue():
+                pass
+            else:
+                raise
+
+    def kill(self):
+        """
+        Terminate the client without removing the mount point.
+        """
+        self.fuse_daemon.stdin.close()
+        try:
+            self.fuse_daemon.wait()
+        except CommandFailedError:
+            pass
+
+    def kill_cleanup(self):
+        """
+        Follow up ``kill`` to get to a clean unmounted state.
+        """
+        self.umount()
+        self.cleanup()
+
+    def teardown(self):
+        """
+        Whatever the state of the mount, get it gone.
+        """
+        super(FuseMount, self).teardown()
+
+        self.umount()
+
+        if self.fuse_daemon and not self.fuse_daemon.finished:
+            self.fuse_daemon.stdin.close()
+            try:
+                self.fuse_daemon.wait()
+            except CommandFailedError:
+                pass
+
+        # Indiscriminate, unlike the touchier cleanup()
+        self.client_remote.run(
+            args=[
+                'rm',
+                '-rf',
+                self.mountpoint,
+            ],
+        )
+
+    def _asok_path(self):
+        return "/var/run/ceph/ceph-client.{0}.*.asok".format(self.client_id)
+
+    @property
+    def _prefix(self):
+        return ""
+
+    def admin_socket(self, args):
+        pyscript = """
+import glob
+import re
+import os
+import subprocess
+
+def find_socket(client_name):
+        asok_path = "{asok_path}"
+        files = glob.glob(asok_path)
+
+        # Given a non-glob path, it better be there
+        if "*" not in asok_path:
+            assert(len(files) == 1)
+            return files[0]
+
+        for f in files:
+                pid = re.match(".*\.(\d+)\.asok$", f).group(1)
+                if os.path.exists("/proc/{{0}}".format(pid)):
+                        return f
+        raise RuntimeError("Client socket {{0}} not found".format(client_name))
+
+print find_socket("{client_name}")
+""".format(
+            asok_path=self._asok_path(),
+            client_name="client.{0}".format(self.client_id))
+
+        # Find the admin socket
+        p = self.client_remote.run(args=[
+            'python', '-c', pyscript
+        ], stdout=StringIO())
+        asok_path = p.stdout.getvalue().strip()
+        log.info("Found client admin socket at {0}".format(asok_path))
+
+        # Query client ID from admin socket
+        p = self.client_remote.run(
+            args=['sudo', self._prefix + 'ceph', '--admin-daemon', asok_path] + args,
+            stdout=StringIO())
+        return json.loads(p.stdout.getvalue())
+
+    def get_global_id(self):
+        """
+        Look up the CephFS client ID for this mount
+        """
+
+        return self.admin_socket(['mds_sessions'])['id']
+
+    def get_osd_epoch(self):
+        """
+        Return 2-tuple of osd_epoch, osd_epoch_barrier
+        """
+        status = self.admin_socket(['status'])
+        return status['osd_epoch'], status['osd_epoch_barrier']
+
+    def get_dentry_count(self):
+        """
+        Return 2-tuple of dentry_count, dentry_pinned_count
+        """
+        status = self.admin_socket(['status'])
+        return status['dentry_count'], status['dentry_pinned_count']
+
+    def set_cache_size(self, size):
+        return self.admin_socket(['config', 'set', 'client_cache_size', str(size)])
diff --git a/src/ceph/qa/tasks/cephfs/kernel_mount.py b/src/ceph/qa/tasks/cephfs/kernel_mount.py
new file mode 100644
index 0000000..bfa1ac6
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/kernel_mount.py
@@ -0,0 +1,267 @@
+from StringIO import StringIO
+import json
+import logging
+from textwrap import dedent
+from teuthology.orchestra.run import CommandFailedError
+from teuthology import misc
+
+from teuthology.orchestra import remote as orchestra_remote
+from teuthology.orchestra import run
+from teuthology.contextutil import MaxWhileTries
+from .mount import CephFSMount
+
+log = logging.getLogger(__name__)
+
+
+UMOUNT_TIMEOUT = 300
+
+
+class KernelMount(CephFSMount):
+    def __init__(self, mons, test_dir, client_id, client_remote,
+                 ipmi_user, ipmi_password, ipmi_domain):
+        super(KernelMount, self).__init__(test_dir, client_id, client_remote)
+        self.mons = mons
+
+        self.mounted = False
+        self.ipmi_user = ipmi_user
+        self.ipmi_password = ipmi_password
+        self.ipmi_domain = ipmi_domain
+
+    def write_secret_file(self, remote, role, keyring, filename):
+        """
+        Stash the keyring in the filename specified.
+        """
+        remote.run(
+            args=[
+                'adjust-ulimits',
+                'ceph-coverage',
+                '{tdir}/archive/coverage'.format(tdir=self.test_dir),
+                'ceph-authtool',
+                '--name={role}'.format(role=role),
+                '--print-key',
+                keyring,
+                run.Raw('>'),
+                filename,
+            ],
+        )
+
+    def mount(self, mount_path=None, mount_fs_name=None):
+        log.info('Mounting kclient client.{id} at {remote} {mnt}...'.format(
+            id=self.client_id, remote=self.client_remote, mnt=self.mountpoint))
+
+        keyring = self.get_keyring_path()
+        secret = '{tdir}/ceph.data/client.{id}.secret'.format(tdir=self.test_dir, id=self.client_id)
+        self.write_secret_file(self.client_remote, 'client.{id}'.format(id=self.client_id),
+                               keyring, secret)
+
+        self.client_remote.run(
+            args=[
+                'mkdir',
+                '--',
+                self.mountpoint,
+            ],
+        )
+
+        if mount_path is None:
+            mount_path = "/"
+
+        opts = 'name={id},secretfile={secret},norequire_active_mds'.format(id=self.client_id,
+                                                      secret=secret)
+
+        if mount_fs_name is not None:
+            opts += ",mds_namespace={0}".format(mount_fs_name)
+
+        self.client_remote.run(
+            args=[
+                'sudo',
+                'adjust-ulimits',
+                'ceph-coverage',
+                '{tdir}/archive/coverage'.format(tdir=self.test_dir),
+                '/sbin/mount.ceph',
+                '{mons}:{mount_path}'.format(mons=','.join(self.mons), mount_path=mount_path),
+                self.mountpoint,
+                '-v',
+                '-o',
+                opts
+            ],
+        )
+
+        self.client_remote.run(
+            args=['sudo', 'chmod', '1777', self.mountpoint])
+
+        self.mounted = True
+
+    def umount(self, force=False):
+        log.debug('Unmounting client client.{id}...'.format(id=self.client_id))
+
+        cmd=['sudo', 'umount', self.mountpoint]
+        if force:
+            cmd.append('-f')
+
+        try:
+            self.client_remote.run(args=cmd)
+        except Exception as e:
+            self.client_remote.run(args=[
+                'sudo',
+                run.Raw('PATH=/usr/sbin:$PATH'),
+                'lsof',
+                run.Raw(';'),
+                'ps', 'auxf',
+            ])
+            raise e
+
+        rproc = self.client_remote.run(
+            args=[
+                'rmdir',
+                '--',
+                self.mountpoint,
+            ],
+            wait=False
+        )
+        run.wait([rproc], UMOUNT_TIMEOUT)
+        self.mounted = False
+
+    def cleanup(self):
+        pass
+
+    def umount_wait(self, force=False, require_clean=False):
+        """
+        Unlike the fuse client, the kernel client's umount is immediate
+        """
+        if not self.is_mounted():
+            return
+
+        try:
+            self.umount(force)
+        except (CommandFailedError, MaxWhileTries):
+            if not force:
+                raise
+
+            self.kill()
+            self.kill_cleanup()
+
+        self.mounted = False
+
+    def is_mounted(self):
+        return self.mounted
+
+    def wait_until_mounted(self):
+        """
+        Unlike the fuse client, the kernel client is up and running as soon
+        as the initial mount() function returns.
+        """
+        assert self.mounted
+
+    def teardown(self):
+        super(KernelMount, self).teardown()
+        if self.mounted:
+            self.umount()
+
+    def kill(self):
+        """
+        The Ceph kernel client doesn't have a mechanism to kill itself (doing
+        that in side the kernel would be weird anyway), so we reboot the whole node
+        to get the same effect.
+
+        We use IPMI to reboot, because we don't want the client to send any
+        releases of capabilities.
+        """
+
+        con = orchestra_remote.getRemoteConsole(self.client_remote.hostname,
+                                                self.ipmi_user,
+                                                self.ipmi_password,
+                                                self.ipmi_domain)
+        con.power_off()
+
+        self.mounted = False
+
+    def kill_cleanup(self):
+        assert not self.mounted
+
+        con = orchestra_remote.getRemoteConsole(self.client_remote.hostname,
+                                                self.ipmi_user,
+                                                self.ipmi_password,
+                                                self.ipmi_domain)
+        con.power_on()
+
+        # Wait for node to come back up after reboot
+        misc.reconnect(None, 300, [self.client_remote])
+
+        # Remove mount directory
+        self.client_remote.run(
+            args=[
+                'rmdir',
+                '--',
+                self.mountpoint,
+            ],
+        )
+
+    def _find_debug_dir(self):
+        """
+        Find the debugfs folder for this mount
+        """
+        pyscript = dedent("""
+            import glob
+            import os
+            import json
+
+            def get_id_to_dir():
+                result = {}
+                for dir in glob.glob("/sys/kernel/debug/ceph/*"):
+                    mds_sessions_lines = open(os.path.join(dir, "mds_sessions")).readlines()
+                    client_id = mds_sessions_lines[1].split()[1].strip('"')
+
+                    result[client_id] = dir
+                return result
+
+            print json.dumps(get_id_to_dir())
+            """)
+
+        p = self.client_remote.run(args=[
+            'sudo', 'python', '-c', pyscript
+        ], stdout=StringIO())
+        client_id_to_dir = json.loads(p.stdout.getvalue())
+
+        try:
+            return client_id_to_dir[self.client_id]
+        except KeyError:
+            log.error("Client id '{0}' debug dir not found (clients seen were: {1})".format(
+                self.client_id, ",".join(client_id_to_dir.keys())
+            ))
+            raise
+
+    def _read_debug_file(self, filename):
+        debug_dir = self._find_debug_dir()
+
+        pyscript = dedent("""
+            import os
+
+            print open(os.path.join("{debug_dir}", "{filename}")).read()
+            """).format(debug_dir=debug_dir, filename=filename)
+
+        p = self.client_remote.run(args=[
+            'sudo', 'python', '-c', pyscript
+        ], stdout=StringIO())
+        return p.stdout.getvalue()
+
+    def get_global_id(self):
+        """
+        Look up the CephFS client ID for this mount, using debugfs.
+        """
+
+        assert self.mounted
+
+        mds_sessions = self._read_debug_file("mds_sessions")
+        lines = mds_sessions.split("\n")
+        return int(lines[0].split()[1])
+
+    def get_osd_epoch(self):
+        """
+        Return 2-tuple of osd_epoch, osd_epoch_barrier
+        """
+        osd_map = self._read_debug_file("osdmap")
+        lines = osd_map.split("\n")
+        first_line_tokens = lines[0].split()
+        epoch, barrier = int(first_line_tokens[1]), int(first_line_tokens[3])
+
+        return epoch, barrier
diff --git a/src/ceph/qa/tasks/cephfs/mount.py b/src/ceph/qa/tasks/cephfs/mount.py
new file mode 100644
index 0000000..4f96e6c
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/mount.py
@@ -0,0 +1,627 @@
+from contextlib import contextmanager
+import json
+import logging
+import datetime
+import time
+from textwrap import dedent
+import os
+from StringIO import StringIO
+from teuthology.orchestra import run
+from teuthology.orchestra.run import CommandFailedError, ConnectionLostError
+
+log = logging.getLogger(__name__)
+
+
+class CephFSMount(object):
+    def __init__(self, test_dir, client_id, client_remote):
+        """
+        :param test_dir: Global teuthology test dir
+        :param client_id: Client ID, the 'foo' in client.foo
+        :param client_remote: Remote instance for the host where client will run
+        """
+
+        self.test_dir = test_dir
+        self.client_id = client_id
+        self.client_remote = client_remote
+        self.mountpoint_dir_name = 'mnt.{id}'.format(id=self.client_id)
+
+        self.test_files = ['a', 'b', 'c']
+
+        self.background_procs = []
+
+    @property
+    def mountpoint(self):
+        return os.path.join(
+            self.test_dir, '{dir_name}'.format(dir_name=self.mountpoint_dir_name))
+
+    def is_mounted(self):
+        raise NotImplementedError()
+
+    def mount(self, mount_path=None, mount_fs_name=None):
+        raise NotImplementedError()
+
+    def umount(self):
+        raise NotImplementedError()
+
+    def umount_wait(self, force=False, require_clean=False):
+        """
+
+        :param force: Expect that the mount will not shutdown cleanly: kill
+                      it hard.
+        :param require_clean: Wait for the Ceph client associated with the
+                              mount (e.g. ceph-fuse) to terminate, and
+                              raise if it doesn't do so cleanly.
+        :return:
+        """
+        raise NotImplementedError()
+
+    def kill_cleanup(self):
+        raise NotImplementedError()
+
+    def kill(self):
+        raise NotImplementedError()
+
+    def cleanup(self):
+        raise NotImplementedError()
+
+    def wait_until_mounted(self):
+        raise NotImplementedError()
+
+    def get_keyring_path(self):
+        return '/etc/ceph/ceph.client.{id}.keyring'.format(id=self.client_id)
+
+    @property
+    def config_path(self):
+        """
+        Path to ceph.conf: override this if you're not a normal systemwide ceph install
+        :return: stringv
+        """
+        return "/etc/ceph/ceph.conf"
+
+    @contextmanager
+    def mounted(self):
+        """
+        A context manager, from an initially unmounted state, to mount
+        this, yield, and then unmount and clean up.
+        """
+        self.mount()
+        self.wait_until_mounted()
+        try:
+            yield
+        finally:
+            self.umount_wait()
+
+    def create_files(self):
+        assert(self.is_mounted())
+
+        for suffix in self.test_files:
+            log.info("Creating file {0}".format(suffix))
+            self.client_remote.run(args=[
+                'sudo', 'touch', os.path.join(self.mountpoint, suffix)
+            ])
+
+    def check_files(self):
+        assert(self.is_mounted())
+
+        for suffix in self.test_files:
+            log.info("Checking file {0}".format(suffix))
+            r = self.client_remote.run(args=[
+                'sudo', 'ls', os.path.join(self.mountpoint, suffix)
+            ], check_status=False)
+            if r.exitstatus != 0:
+                raise RuntimeError("Expected file {0} not found".format(suffix))
+
+    def create_destroy(self):
+        assert(self.is_mounted())
+
+        filename = "{0} {1}".format(datetime.datetime.now(), self.client_id)
+        log.debug("Creating test file {0}".format(filename))
+        self.client_remote.run(args=[
+            'sudo', 'touch', os.path.join(self.mountpoint, filename)
+        ])
+        log.debug("Deleting test file {0}".format(filename))
+        self.client_remote.run(args=[
+            'sudo', 'rm', '-f', os.path.join(self.mountpoint, filename)
+        ])
+
+    def _run_python(self, pyscript):
+        return self.client_remote.run(args=[
+            'sudo', 'adjust-ulimits', 'daemon-helper', 'kill', 'python', '-c', pyscript
+        ], wait=False, stdin=run.PIPE, stdout=StringIO())
+
+    def run_python(self, pyscript):
+        p = self._run_python(pyscript)
+        p.wait()
+        return p.stdout.getvalue().strip()
+
+    def run_shell(self, args, wait=True):
+        args = ["cd", self.mountpoint, run.Raw('&&'), "sudo"] + args
+        return self.client_remote.run(args=args, stdout=StringIO(),
+                                      stderr=StringIO(), wait=wait)
+
+    def open_no_data(self, basename):
+        """
+        A pure metadata operation
+        """
+        assert(self.is_mounted())
+
+        path = os.path.join(self.mountpoint, basename)
+
+        p = self._run_python(dedent(
+            """
+            f = open("{path}", 'w')
+            """.format(path=path)
+        ))
+        p.wait()
+
+    def open_background(self, basename="background_file"):
+        """
+        Open a file for writing, then block such that the client
+        will hold a capability.
+
+        Don't return until the remote process has got as far as opening
+        the file, then return the RemoteProcess instance.
+        """
+        assert(self.is_mounted())
+
+        path = os.path.join(self.mountpoint, basename)
+
+        pyscript = dedent("""
+            import time
+
+            f = open("{path}", 'w')
+            f.write('content')
+            f.flush()
+            f.write('content2')
+            while True:
+                time.sleep(1)
+            """).format(path=path)
+
+        rproc = self._run_python(pyscript)
+        self.background_procs.append(rproc)
+
+        # This wait would not be sufficient if the file had already
+        # existed, but it's simple and in practice users of open_background
+        # are not using it on existing files.
+        self.wait_for_visible(basename)
+
+        return rproc
+
+    def wait_for_visible(self, basename="background_file", timeout=30):
+        i = 0
+        while i < timeout:
+            r = self.client_remote.run(args=[
+                'sudo', 'ls', os.path.join(self.mountpoint, basename)
+            ], check_status=False)
+            if r.exitstatus == 0:
+                log.debug("File {0} became visible from {1} after {2}s".format(
+                    basename, self.client_id, i))
+                return
+            else:
+                time.sleep(1)
+                i += 1
+
+        raise RuntimeError("Timed out after {0}s waiting for {1} to become visible from {2}".format(
+            i, basename, self.client_id))
+
+    def lock_background(self, basename="background_file", do_flock=True):
+        """
+        Open and lock a files for writing, hold the lock in a background process
+        """
+        assert(self.is_mounted())
+
+        path = os.path.join(self.mountpoint, basename)
+
+        script_builder = """
+            import time
+            import fcntl
+            import struct"""
+        if do_flock:
+            script_builder += """
+            f1 = open("{path}-1", 'w')
+            fcntl.flock(f1, fcntl.LOCK_EX | fcntl.LOCK_NB)"""
+        script_builder += """
+            f2 = open("{path}-2", 'w')
+            lockdata = struct.pack('hhllhh', fcntl.F_WRLCK, 0, 0, 0, 0, 0)
+            fcntl.fcntl(f2, fcntl.F_SETLK, lockdata)
+            while True:
+                time.sleep(1)
+            """
+
+        pyscript = dedent(script_builder).format(path=path)
+
+        log.info("lock_background file {0}".format(basename))
+        rproc = self._run_python(pyscript)
+        self.background_procs.append(rproc)
+        return rproc
+
+    def lock_and_release(self, basename="background_file"):
+        assert(self.is_mounted())
+
+        path = os.path.join(self.mountpoint, basename)
+
+        script = """
+            import time
+            import fcntl
+            import struct
+            f1 = open("{path}-1", 'w')
+            fcntl.flock(f1, fcntl.LOCK_EX)
+            f2 = open("{path}-2", 'w')
+            lockdata = struct.pack('hhllhh', fcntl.F_WRLCK, 0, 0, 0, 0, 0)
+            fcntl.fcntl(f2, fcntl.F_SETLK, lockdata)
+            """
+        pyscript = dedent(script).format(path=path)
+
+        log.info("lock_and_release file {0}".format(basename))
+        return self._run_python(pyscript)
+
+    def check_filelock(self, basename="background_file", do_flock=True):
+        assert(self.is_mounted())
+
+        path = os.path.join(self.mountpoint, basename)
+
+        script_builder = """
+            import fcntl
+            import errno
+            import struct"""
+        if do_flock:
+            script_builder += """
+            f1 = open("{path}-1", 'r')
+            try:
+                fcntl.flock(f1, fcntl.LOCK_EX | fcntl.LOCK_NB)
+            except IOError, e:
+                if e.errno == errno.EAGAIN:
+                    pass
+            else:
+                raise RuntimeError("flock on file {path}-1 not found")"""
+        script_builder += """
+            f2 = open("{path}-2", 'r')
+            try:
+                lockdata = struct.pack('hhllhh', fcntl.F_WRLCK, 0, 0, 0, 0, 0)
+                fcntl.fcntl(f2, fcntl.F_SETLK, lockdata)
+            except IOError, e:
+                if e.errno == errno.EAGAIN:
+                    pass
+            else:
+                raise RuntimeError("posix lock on file {path}-2 not found")
+            """
+        pyscript = dedent(script_builder).format(path=path)
+
+        log.info("check lock on file {0}".format(basename))
+        self.client_remote.run(args=[
+            'sudo', 'python', '-c', pyscript
+        ])
+
+    def write_background(self, basename="background_file", loop=False):
+        """
+        Open a file for writing, complete as soon as you can
+        :param basename:
+        :return:
+        """
+        assert(self.is_mounted())
+
+        path = os.path.join(self.mountpoint, basename)
+
+        pyscript = dedent("""
+            import os
+            import time
+
+            fd = os.open("{path}", os.O_RDWR | os.O_CREAT, 0644)
+            try:
+                while True:
+                    os.write(fd, 'content')
+                    time.sleep(1)
+                    if not {loop}:
+                        break
+            except IOError, e:
+                pass
+            os.close(fd)
+            """).format(path=path, loop=str(loop))
+
+        rproc = self._run_python(pyscript)
+        self.background_procs.append(rproc)
+        return rproc
+
+    def write_n_mb(self, filename, n_mb, seek=0, wait=True):
+        """
+        Write the requested number of megabytes to a file
+        """
+        assert(self.is_mounted())
+
+        return self.run_shell(["dd", "if=/dev/urandom", "of={0}".format(filename),
+                               "bs=1M", "conv=fdatasync",
+                               "count={0}".format(n_mb),
+                               "seek={0}".format(seek)
+                               ], wait=wait)
+
+    def write_test_pattern(self, filename, size):
+        log.info("Writing {0} bytes to {1}".format(size, filename))
+        return self.run_python(dedent("""
+            import zlib
+            path = "{path}"
+            f = open(path, 'w')
+            for i in range(0, {size}):
+                val = zlib.crc32("%s" % i) & 7
+                f.write(chr(val))
+            f.close()
+        """.format(
+            path=os.path.join(self.mountpoint, filename),
+            size=size
+        )))
+
+    def validate_test_pattern(self, filename, size):
+        log.info("Validating {0} bytes from {1}".format(size, filename))
+        return self.run_python(dedent("""
+            import zlib
+            path = "{path}"
+            f = open(path, 'r')
+            bytes = f.read()
+            f.close()
+            if len(bytes) != {size}:
+                raise RuntimeError("Bad length {{0}} vs. expected {{1}}".format(
+                    len(bytes), {size}
+                ))
+            for i, b in enumerate(bytes):
+                val = zlib.crc32("%s" % i) & 7
+                if b != chr(val):
+                    raise RuntimeError("Bad data at offset {{0}}".format(i))
+        """.format(
+            path=os.path.join(self.mountpoint, filename),
+            size=size
+        )))
+
+    def open_n_background(self, fs_path, count):
+        """
+        Open N files for writing, hold them open in a background process
+
+        :param fs_path: Path relative to CephFS root, e.g. "foo/bar"
+        :return: a RemoteProcess
+        """
+        assert(self.is_mounted())
+
+        abs_path = os.path.join(self.mountpoint, fs_path)
+
+        pyscript = dedent("""
+            import sys
+            import time
+            import os
+
+            n = {count}
+            abs_path = "{abs_path}"
+
+            if not os.path.exists(os.path.dirname(abs_path)):
+                os.makedirs(os.path.dirname(abs_path))
+
+            handles = []
+            for i in range(0, n):
+                fname = "{{0}}_{{1}}".format(abs_path, i)
+                handles.append(open(fname, 'w'))
+
+            while True:
+                time.sleep(1)
+            """).format(abs_path=abs_path, count=count)
+
+        rproc = self._run_python(pyscript)
+        self.background_procs.append(rproc)
+        return rproc
+
+    def create_n_files(self, fs_path, count, sync=False):
+        assert(self.is_mounted())
+
+        abs_path = os.path.join(self.mountpoint, fs_path)
+
+        pyscript = dedent("""
+            import sys
+            import time
+            import os
+
+            n = {count}
+            abs_path = "{abs_path}"
+
+            if not os.path.exists(os.path.dirname(abs_path)):
+                os.makedirs(os.path.dirname(abs_path))
+
+            for i in range(0, n):
+                fname = "{{0}}_{{1}}".format(abs_path, i)
+                h = open(fname, 'w')
+                h.write('content')
+                if {sync}:
+                    h.flush()
+                    os.fsync(h.fileno())
+                h.close()
+            """).format(abs_path=abs_path, count=count, sync=str(sync))
+
+        self.run_python(pyscript)
+
+    def teardown(self):
+        for p in self.background_procs:
+            log.info("Terminating background process")
+            self._kill_background(p)
+
+        self.background_procs = []
+
+    def _kill_background(self, p):
+        if p.stdin:
+            p.stdin.close()
+            try:
+                p.wait()
+            except (CommandFailedError, ConnectionLostError):
+                pass
+
+    def kill_background(self, p):
+        """
+        For a process that was returned by one of the _background member functions,
+        kill it hard.
+        """
+        self._kill_background(p)
+        self.background_procs.remove(p)
+
+    def get_global_id(self):
+        raise NotImplementedError()
+
+    def get_osd_epoch(self):
+        raise NotImplementedError()
+
+    def stat(self, fs_path, wait=True):
+        """
+        stat a file, and return the result as a dictionary like this:
+        {
+          "st_ctime": 1414161137.0,
+          "st_mtime": 1414161137.0,
+          "st_nlink": 33,
+          "st_gid": 0,
+          "st_dev": 16777218,
+          "st_size": 1190,
+          "st_ino": 2,
+          "st_uid": 0,
+          "st_mode": 16877,
+          "st_atime": 1431520593.0
+        }
+
+        Raises exception on absent file.
+        """
+        abs_path = os.path.join(self.mountpoint, fs_path)
+
+        pyscript = dedent("""
+            import os
+            import stat
+            import json
+            import sys
+
+            try:
+                s = os.stat("{path}")
+            except OSError as e:
+                sys.exit(e.errno)
+
+            attrs = ["st_mode", "st_ino", "st_dev", "st_nlink", "st_uid", "st_gid", "st_size", "st_atime", "st_mtime", "st_ctime"]
+            print json.dumps(
+                dict([(a, getattr(s, a)) for a in attrs]),
+                indent=2)
+            """).format(path=abs_path)
+        proc = self._run_python(pyscript)
+        if wait:
+            proc.wait()
+            return json.loads(proc.stdout.getvalue().strip())
+        else:
+            return proc
+
+    def touch(self, fs_path):
+        """
+        Create a dentry if it doesn't already exist.  This python
+        implementation exists because the usual command line tool doesn't
+        pass through error codes like EIO.
+
+        :param fs_path:
+        :return:
+        """
+        abs_path = os.path.join(self.mountpoint, fs_path)
+        pyscript = dedent("""
+            import sys
+            import errno
+
+            try:
+                f = open("{path}", "w")
+                f.close()
+            except IOError as e:
+                sys.exit(errno.EIO)
+            """).format(path=abs_path)
+        proc = self._run_python(pyscript)
+        proc.wait()
+
+    def path_to_ino(self, fs_path, follow_symlinks=True):
+        abs_path = os.path.join(self.mountpoint, fs_path)
+
+        if follow_symlinks:
+            pyscript = dedent("""
+                import os
+                import stat
+
+                print os.stat("{path}").st_ino
+                """).format(path=abs_path)
+        else:
+            pyscript = dedent("""
+                import os
+                import stat
+
+                print os.lstat("{path}").st_ino
+                """).format(path=abs_path)
+
+        proc = self._run_python(pyscript)
+        proc.wait()
+        return int(proc.stdout.getvalue().strip())
+
+    def path_to_nlink(self, fs_path):
+        abs_path = os.path.join(self.mountpoint, fs_path)
+
+        pyscript = dedent("""
+            import os
+            import stat
+
+            print os.stat("{path}").st_nlink
+            """).format(path=abs_path)
+
+        proc = self._run_python(pyscript)
+        proc.wait()
+        return int(proc.stdout.getvalue().strip())
+
+    def ls(self, path=None):
+        """
+        Wrap ls: return a list of strings
+        """
+        cmd = ["ls"]
+        if path:
+            cmd.append(path)
+
+        ls_text = self.run_shell(cmd).stdout.getvalue().strip()
+
+        if ls_text:
+            return ls_text.split("\n")
+        else:
+            # Special case because otherwise split on empty string
+            # gives you [''] instead of []
+            return []
+
+    def setfattr(self, path, key, val):
+        """
+        Wrap setfattr.
+
+        :param path: relative to mount point
+        :param key: xattr name
+        :param val: xattr value
+        :return: None
+        """
+        self.run_shell(["setfattr", "-n", key, "-v", val, path])
+
+    def getfattr(self, path, attr):
+        """
+        Wrap getfattr: return the values of a named xattr on one file, or
+        None if the attribute is not found.
+
+        :return: a string
+        """
+        p = self.run_shell(["getfattr", "--only-values", "-n", attr, path], wait=False)
+        try:
+            p.wait()
+        except CommandFailedError as e:
+            if e.exitstatus == 1 and "No such attribute" in p.stderr.getvalue():
+                return None
+            else:
+                raise
+
+        return p.stdout.getvalue()
+
+    def df(self):
+        """
+        Wrap df: return a dict of usage fields in bytes
+        """
+
+        p = self.run_shell(["df", "-B1", "."])
+        lines = p.stdout.getvalue().strip().split("\n")
+        fs, total, used, avail = lines[1].split()[:4]
+        log.warn(lines)
+
+        return {
+            "total": int(total),
+            "used": int(used),
+            "available": int(avail)
+        }
diff --git a/src/ceph/qa/tasks/cephfs/test_auto_repair.py b/src/ceph/qa/tasks/cephfs/test_auto_repair.py
new file mode 100644
index 0000000..c0aa2e4
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_auto_repair.py
@@ -0,0 +1,90 @@
+
+"""
+Exercise the MDS's auto repair functions
+"""
+
+import logging
+import time
+
+from teuthology.orchestra.run import CommandFailedError
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+
+
+log = logging.getLogger(__name__)
+
+
+# Arbitrary timeouts for operations involving restarting
+# an MDS or waiting for it to come up
+MDS_RESTART_GRACE = 60
+
+
+class TestMDSAutoRepair(CephFSTestCase):
+    def test_backtrace_repair(self):
+        """
+        MDS should verify/fix backtrace on fetch dirfrag
+        """
+
+        self.mount_a.run_shell(["mkdir", "testdir1"])
+        self.mount_a.run_shell(["touch", "testdir1/testfile"])
+        dir_objname = "{:x}.00000000".format(self.mount_a.path_to_ino("testdir1"))
+
+        # drop inodes caps
+        self.mount_a.umount_wait()
+
+        # flush journal entries to dirfrag objects, and expire journal
+        self.fs.mds_asok(['flush', 'journal'])
+
+        # Restart the MDS to drop the metadata cache (because we expired the journal,
+        # nothing gets replayed into cache on restart)
+        self.fs.mds_stop()
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        # remove testdir1's backtrace
+        self.fs.rados(["rmxattr", dir_objname, "parent"])
+
+        # readdir (fetch dirfrag) should fix testdir1's backtrace
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        self.mount_a.run_shell(["ls", "testdir1"])
+
+        # flush journal entries to dirfrag objects
+        self.fs.mds_asok(['flush', 'journal'])
+
+        # check if backtrace exists
+        self.fs.rados(["getxattr", dir_objname, "parent"])
+
+    def test_mds_readonly(self):
+        """
+        test if MDS behave correct when it's readonly
+        """
+        # operation should successd when MDS is not readonly
+        self.mount_a.run_shell(["touch", "test_file1"])
+        writer = self.mount_a.write_background(loop=True)
+
+        time.sleep(10)
+        self.assertFalse(writer.finished)
+
+        # force MDS to read-only mode
+        self.fs.mds_asok(['force_readonly'])
+        time.sleep(10)
+
+        # touching test file should fail
+        try:
+            self.mount_a.run_shell(["touch", "test_file1"])
+        except CommandFailedError:
+            pass
+        else:
+            self.assertTrue(False)
+
+        # background writer also should fail
+        self.assertTrue(writer.finished)
+
+        # The MDS should report its readonly health state to the mon
+        self.wait_for_health("MDS_READ_ONLY", timeout=30)
+
+        # restart mds to make it writable
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        self.wait_for_health_clear(timeout=30)
diff --git a/src/ceph/qa/tasks/cephfs/test_backtrace.py b/src/ceph/qa/tasks/cephfs/test_backtrace.py
new file mode 100644
index 0000000..af246a1
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_backtrace.py
@@ -0,0 +1,78 @@
+
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+
+
+class TestBacktrace(CephFSTestCase):
+    def test_backtrace(self):
+        """
+        That the 'parent' and 'layout' xattrs on the head objects of files
+        are updated correctly.
+        """
+
+        old_data_pool_name = self.fs.get_data_pool_name()
+        old_pool_id = self.fs.get_data_pool_id()
+
+        # Create a file for subsequent checks
+        self.mount_a.run_shell(["mkdir", "parent_a"])
+        self.mount_a.run_shell(["touch", "parent_a/alpha"])
+        file_ino = self.mount_a.path_to_ino("parent_a/alpha")
+
+        # That backtrace and layout are written after initial flush
+        self.fs.mds_asok(["flush", "journal"])
+        backtrace = self.fs.read_backtrace(file_ino)
+        self.assertEqual(['alpha', 'parent_a'], [a['dname'] for a in backtrace['ancestors']])
+        layout = self.fs.read_layout(file_ino)
+        self.assertDictEqual(layout, {
+            "stripe_unit": 4194304,
+            "stripe_count": 1,
+            "object_size": 4194304,
+            "pool_id": old_pool_id,
+            "pool_ns": "",
+        })
+        self.assertEqual(backtrace['pool'], old_pool_id)
+
+        # That backtrace is written after parentage changes
+        self.mount_a.run_shell(["mkdir", "parent_b"])
+        self.mount_a.run_shell(["mv", "parent_a/alpha", "parent_b/alpha"])
+
+        self.fs.mds_asok(["flush", "journal"])
+        backtrace = self.fs.read_backtrace(file_ino)
+        self.assertEqual(['alpha', 'parent_b'], [a['dname'] for a in backtrace['ancestors']])
+
+        # Create a new data pool
+        new_pool_name = "data_new"
+        new_pool_id = self.fs.add_data_pool(new_pool_name)
+
+        # That an object which has switched pools gets its backtrace updated
+        self.mount_a.setfattr("./parent_b/alpha",
+                              "ceph.file.layout.pool", new_pool_name)
+        self.fs.mds_asok(["flush", "journal"])
+        backtrace_old_pool = self.fs.read_backtrace(file_ino, pool=old_data_pool_name)
+        self.assertEqual(backtrace_old_pool['pool'], new_pool_id)
+        backtrace_new_pool = self.fs.read_backtrace(file_ino, pool=new_pool_name)
+        self.assertEqual(backtrace_new_pool['pool'], new_pool_id)
+        new_pool_layout = self.fs.read_layout(file_ino, pool=new_pool_name)
+        self.assertEqual(new_pool_layout['pool_id'], new_pool_id)
+        self.assertEqual(new_pool_layout['pool_ns'], '')
+
+        # That subsequent linkage changes are only written to new pool backtrace
+        self.mount_a.run_shell(["mkdir", "parent_c"])
+        self.mount_a.run_shell(["mv", "parent_b/alpha", "parent_c/alpha"])
+        self.fs.mds_asok(["flush", "journal"])
+        backtrace_old_pool = self.fs.read_backtrace(file_ino, pool=old_data_pool_name)
+        self.assertEqual(['alpha', 'parent_b'], [a['dname'] for a in backtrace_old_pool['ancestors']])
+        backtrace_new_pool = self.fs.read_backtrace(file_ino, pool=new_pool_name)
+        self.assertEqual(['alpha', 'parent_c'], [a['dname'] for a in backtrace_new_pool['ancestors']])
+
+        # That layout is written to new pool after change to other field in layout
+        self.mount_a.setfattr("./parent_c/alpha",
+                              "ceph.file.layout.object_size", "8388608")
+
+        self.fs.mds_asok(["flush", "journal"])
+        new_pool_layout = self.fs.read_layout(file_ino, pool=new_pool_name)
+        self.assertEqual(new_pool_layout['object_size'], 8388608)
+
+        # ...but not to the old pool: the old pool's backtrace points to the new pool, and that's enough,
+        # we don't update the layout in all the old pools whenever it changes
+        old_pool_layout = self.fs.read_layout(file_ino, pool=old_data_pool_name)
+        self.assertEqual(old_pool_layout['object_size'], 4194304)
diff --git a/src/ceph/qa/tasks/cephfs/test_cap_flush.py b/src/ceph/qa/tasks/cephfs/test_cap_flush.py
new file mode 100644
index 0000000..1cd102f
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_cap_flush.py
@@ -0,0 +1,64 @@
+
+import os
+import time
+from textwrap import dedent
+from unittest import SkipTest
+from tasks.cephfs.fuse_mount import FuseMount
+from tasks.cephfs.cephfs_test_case import CephFSTestCase, for_teuthology
+
+class TestCapFlush(CephFSTestCase):
+    @for_teuthology
+    def test_replay_create(self):
+        """
+        MDS starts to handle client caps when it enters clientreplay stage.
+        When handling a client cap in clientreplay stage, it's possible that
+        corresponding inode does not exist because the client request which
+        creates inode hasn't been replayed.
+        """
+
+        if not isinstance(self.mount_a, FuseMount):
+            raise SkipTest("Require FUSE client to inject client release failure")
+
+        dir_path = os.path.join(self.mount_a.mountpoint, "testdir")
+        py_script = dedent("""
+            import os
+            os.mkdir("{0}")
+            fd = os.open("{0}", os.O_RDONLY)
+            os.fchmod(fd, 0777)
+            os.fsync(fd)
+            """).format(dir_path)
+        self.mount_a.run_python(py_script)
+
+        self.fs.mds_asok(["flush", "journal"])
+
+        # client will only get unsafe replay
+        self.fs.mds_asok(["config", "set", "mds_log_pause", "1"])
+
+        file_name = "testfile"
+        file_path = dir_path + "/" + file_name
+
+        # Create a file and modify its mode. ceph-fuse will mark Ax cap dirty
+        py_script = dedent("""
+            import os
+            os.chdir("{0}")
+            os.setgid(65534)
+            os.setuid(65534)
+            fd = os.open("{1}", os.O_CREAT | os.O_RDWR, 0644)
+            os.fchmod(fd, 0640)
+            """).format(dir_path, file_name)
+        self.mount_a.run_python(py_script)
+
+        # Modify file mode by different user. ceph-fuse will send a setattr request
+        self.mount_a.run_shell(["chmod", "600", file_path], wait=False)
+
+        time.sleep(10)
+
+        # Restart mds. Client will re-send the unsafe request and cap flush
+        self.fs.mds_stop()
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        mode = self.mount_a.run_shell(['stat', '-c' '%a', file_path]).stdout.getvalue().strip()
+        # If the cap flush get dropped, mode should be 0644.
+        # (Ax cap stays in dirty state, which prevents setattr reply from updating file mode)
+        self.assertEqual(mode, "600")
diff --git a/src/ceph/qa/tasks/cephfs/test_client_limits.py b/src/ceph/qa/tasks/cephfs/test_client_limits.py
new file mode 100644
index 0000000..cb5e3a4
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_client_limits.py
@@ -0,0 +1,239 @@
+
+"""
+Exercise the MDS's behaviour when clients and the MDCache reach or
+exceed the limits of how many caps/inodes they should hold.
+"""
+
+import logging
+from textwrap import dedent
+from unittest import SkipTest
+from teuthology.orchestra.run import CommandFailedError
+from tasks.cephfs.cephfs_test_case import CephFSTestCase, needs_trimming
+from tasks.cephfs.fuse_mount import FuseMount
+import os
+
+
+log = logging.getLogger(__name__)
+
+
+# Arbitrary timeouts for operations involving restarting
+# an MDS or waiting for it to come up
+MDS_RESTART_GRACE = 60
+
+# Hardcoded values from Server::recall_client_state
+CAP_RECALL_RATIO = 0.8
+CAP_RECALL_MIN = 100
+
+
+class TestClientLimits(CephFSTestCase):
+    REQUIRE_KCLIENT_REMOTE = True
+    CLIENTS_REQUIRED = 2
+
+    def _test_client_pin(self, use_subdir, open_files):
+        """
+        When a client pins an inode in its cache, for example because the file is held open,
+        it should reject requests from the MDS to trim these caps.  The MDS should complain
+        to the user that it is unable to enforce its cache size limits because of this
+        objectionable client.
+
+        :param use_subdir: whether to put test files in a subdir or use root
+        """
+
+        cache_size = open_files/2
+
+        self.set_conf('mds', 'mds cache size', cache_size)
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        mds_min_caps_per_client = int(self.fs.get_config("mds_min_caps_per_client"))
+        self.assertTrue(open_files >= mds_min_caps_per_client)
+        mds_max_ratio_caps_per_client = float(self.fs.get_config("mds_max_ratio_caps_per_client"))
+
+        mount_a_client_id = self.mount_a.get_global_id()
+        path = "subdir/mount_a" if use_subdir else "mount_a"
+        open_proc = self.mount_a.open_n_background(path, open_files)
+
+        # Client should now hold:
+        # `open_files` caps for the open files
+        # 1 cap for root
+        # 1 cap for subdir
+        self.wait_until_equal(lambda: self.get_session(mount_a_client_id)['num_caps'],
+                              open_files + (2 if use_subdir else 1),
+                              timeout=600,
+                              reject_fn=lambda x: x > open_files + 2)
+
+        # MDS should not be happy about that, as the client is failing to comply
+        # with the SESSION_RECALL messages it is being sent
+        mds_recall_state_timeout = float(self.fs.get_config("mds_recall_state_timeout"))
+        self.wait_for_health("MDS_CLIENT_RECALL", mds_recall_state_timeout+10)
+
+        # We can also test that the MDS health warning for oversized
+        # cache is functioning as intended.
+        self.wait_for_health("MDS_CACHE_OVERSIZED",
+                mds_recall_state_timeout + 10)
+
+        # When the client closes the files, it should retain only as many caps as allowed
+        # under the SESSION_RECALL policy
+        log.info("Terminating process holding files open")
+        open_proc.stdin.close()
+        try:
+            open_proc.wait()
+        except CommandFailedError:
+            # We killed it, so it raises an error
+            pass
+
+        # The remaining caps should comply with the numbers sent from MDS in SESSION_RECALL message,
+        # which depend on the caps outstanding, cache size and overall ratio
+        recall_expected_value = int((1.0-mds_max_ratio_caps_per_client)*(open_files+2))
+        def expected_caps():
+            num_caps = self.get_session(mount_a_client_id)['num_caps']
+            if num_caps < mds_min_caps_per_client:
+                raise RuntimeError("client caps fell below min!")
+            elif num_caps == mds_min_caps_per_client:
+                return True
+            elif recall_expected_value*.95 <= num_caps <= recall_expected_value*1.05:
+                return True
+            else:
+                return False
+
+        self.wait_until_true(expected_caps, timeout=60)
+
+    @needs_trimming
+    def test_client_pin_root(self):
+        self._test_client_pin(False, 400)
+
+    @needs_trimming
+    def test_client_pin(self):
+        self._test_client_pin(True, 800)
+
+    @needs_trimming
+    def test_client_pin_mincaps(self):
+        self._test_client_pin(True, 200)
+
+    def test_client_release_bug(self):
+        """
+        When a client has a bug (which we will simulate) preventing it from releasing caps,
+        the MDS should notice that releases are not being sent promptly, and generate a health
+        metric to that effect.
+        """
+
+        # The debug hook to inject the failure only exists in the fuse client
+        if not isinstance(self.mount_a, FuseMount):
+            raise SkipTest("Require FUSE client to inject client release failure")
+
+        self.set_conf('client.{0}'.format(self.mount_a.client_id), 'client inject release failure', 'true')
+        self.mount_a.teardown()
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        mount_a_client_id = self.mount_a.get_global_id()
+
+        # Client A creates a file.  He will hold the write caps on the file, and later (simulated bug) fail
+        # to comply with the MDSs request to release that cap
+        self.mount_a.run_shell(["touch", "file1"])
+
+        # Client B tries to stat the file that client A created
+        rproc = self.mount_b.write_background("file1")
+
+        # After mds_revoke_cap_timeout, we should see a health warning (extra lag from
+        # MDS beacon period)
+        mds_revoke_cap_timeout = float(self.fs.get_config("mds_revoke_cap_timeout"))
+        self.wait_for_health("MDS_CLIENT_LATE_RELEASE", mds_revoke_cap_timeout + 10)
+
+        # Client B should still be stuck
+        self.assertFalse(rproc.finished)
+
+        # Kill client A
+        self.mount_a.kill()
+        self.mount_a.kill_cleanup()
+
+        # Client B should complete
+        self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
+        rproc.wait()
+
+    def test_client_oldest_tid(self):
+        """
+        When a client does not advance its oldest tid, the MDS should notice that
+        and generate health warnings.
+        """
+
+        # num of requests client issues
+        max_requests = 1000
+
+        # The debug hook to inject the failure only exists in the fuse client
+        if not isinstance(self.mount_a, FuseMount):
+            raise SkipTest("Require FUSE client to inject client release failure")
+
+        self.set_conf('client', 'client inject fixed oldest tid', 'true')
+        self.mount_a.teardown()
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        self.fs.mds_asok(['config', 'set', 'mds_max_completed_requests', '{0}'.format(max_requests)])
+
+        # Create lots of files
+        self.mount_a.create_n_files("testdir/file1", max_requests + 100)
+
+        # Create a few files synchronously. This makes sure previous requests are completed
+        self.mount_a.create_n_files("testdir/file2", 5, True)
+
+        # Wait for the health warnings. Assume mds can handle 10 request per second at least
+        self.wait_for_health("MDS_CLIENT_OLDEST_TID", max_requests / 10)
+
+    def _test_client_cache_size(self, mount_subdir):
+        """
+        check if client invalidate kernel dcache according to its cache size config
+        """
+
+        # The debug hook to inject the failure only exists in the fuse client
+        if not isinstance(self.mount_a, FuseMount):
+            raise SkipTest("Require FUSE client to inject client release failure")
+
+        if mount_subdir:
+            # fuse assigns a fix inode number (1) to root inode. But in mounting into
+            # subdir case, the actual inode number of root is not 1. This mismatch
+            # confuses fuse_lowlevel_notify_inval_entry() when invalidating dentries
+            # in root directory.
+            self.mount_a.run_shell(["mkdir", "subdir"])
+            self.mount_a.umount_wait()
+            self.set_conf('client', 'client mountpoint', '/subdir')
+            self.mount_a.mount()
+            self.mount_a.wait_until_mounted()
+            root_ino = self.mount_a.path_to_ino(".")
+            self.assertEqual(root_ino, 1);
+
+        dir_path = os.path.join(self.mount_a.mountpoint, "testdir")
+
+        mkdir_script = dedent("""
+            import os
+            os.mkdir("{path}")
+            for n in range(0, {num_dirs}):
+                os.mkdir("{path}/dir{{0}}".format(n))
+            """)
+
+        num_dirs = 1000
+        self.mount_a.run_python(mkdir_script.format(path=dir_path, num_dirs=num_dirs))
+        self.mount_a.run_shell(["sync"])
+
+        dentry_count, dentry_pinned_count = self.mount_a.get_dentry_count()
+        self.assertGreaterEqual(dentry_count, num_dirs)
+        self.assertGreaterEqual(dentry_pinned_count, num_dirs)
+
+        cache_size = num_dirs / 10
+        self.mount_a.set_cache_size(cache_size)
+
+        def trimmed():
+            dentry_count, dentry_pinned_count = self.mount_a.get_dentry_count()
+            log.info("waiting, dentry_count, dentry_pinned_count: {0}, {1}".format(
+                dentry_count, dentry_pinned_count
+            ))
+            if dentry_count > cache_size or dentry_pinned_count > cache_size:
+                return False
+
+            return True
+
+        self.wait_until_true(trimmed, 30)
+
+    @needs_trimming
+    def test_client_cache_size(self):
+        self._test_client_cache_size(False)
+        self._test_client_cache_size(True)
diff --git a/src/ceph/qa/tasks/cephfs/test_client_recovery.py b/src/ceph/qa/tasks/cephfs/test_client_recovery.py
new file mode 100644
index 0000000..fd58c14
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_client_recovery.py
@@ -0,0 +1,474 @@
+
+"""
+Teuthology task for exercising CephFS client recovery
+"""
+
+import logging
+from textwrap import dedent
+import time
+import distutils.version as version
+import re
+import os
+
+from teuthology.orchestra.run import CommandFailedError, ConnectionLostError
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+from teuthology.packaging import get_package_version
+
+
+log = logging.getLogger(__name__)
+
+
+# Arbitrary timeouts for operations involving restarting
+# an MDS or waiting for it to come up
+MDS_RESTART_GRACE = 60
+
+
+class TestClientNetworkRecovery(CephFSTestCase):
+    REQUIRE_KCLIENT_REMOTE = True
+    REQUIRE_ONE_CLIENT_REMOTE = True
+    CLIENTS_REQUIRED = 2
+
+    LOAD_SETTINGS = ["mds_session_timeout", "mds_reconnect_timeout", "ms_max_backoff"]
+
+    # Environment references
+    mds_session_timeout = None
+    mds_reconnect_timeout = None
+    ms_max_backoff = None
+
+    def test_network_death(self):
+        """
+        Simulate software freeze or temporary network failure.
+
+        Check that the client blocks I/O during failure, and completes
+        I/O after failure.
+        """
+
+        # We only need one client
+        self.mount_b.umount_wait()
+
+        # Initially our one client session should be visible
+        client_id = self.mount_a.get_global_id()
+        ls_data = self._session_list()
+        self.assert_session_count(1, ls_data)
+        self.assertEqual(ls_data[0]['id'], client_id)
+        self.assert_session_state(client_id, "open")
+
+        # ...and capable of doing I/O without blocking
+        self.mount_a.create_files()
+
+        # ...but if we turn off the network
+        self.fs.set_clients_block(True)
+
+        # ...and try and start an I/O
+        write_blocked = self.mount_a.write_background()
+
+        # ...then it should block
+        self.assertFalse(write_blocked.finished)
+        self.assert_session_state(client_id, "open")
+        time.sleep(self.mds_session_timeout * 1.5)  # Long enough for MDS to consider session stale
+        self.assertFalse(write_blocked.finished)
+        self.assert_session_state(client_id, "stale")
+
+        # ...until we re-enable I/O
+        self.fs.set_clients_block(False)
+
+        # ...when it should complete promptly
+        a = time.time()
+        self.wait_until_true(lambda: write_blocked.finished, self.ms_max_backoff * 2)
+        write_blocked.wait()  # Already know we're finished, wait() to raise exception on errors
+        recovery_time = time.time() - a
+        log.info("recovery time: {0}".format(recovery_time))
+        self.assert_session_state(client_id, "open")
+
+
+class TestClientRecovery(CephFSTestCase):
+    REQUIRE_KCLIENT_REMOTE = True
+    CLIENTS_REQUIRED = 2
+
+    LOAD_SETTINGS = ["mds_session_timeout", "mds_reconnect_timeout", "ms_max_backoff"]
+
+    # Environment references
+    mds_session_timeout = None
+    mds_reconnect_timeout = None
+    ms_max_backoff = None
+
+    def test_basic(self):
+        # Check that two clients come up healthy and see each others' files
+        # =====================================================
+        self.mount_a.create_files()
+        self.mount_a.check_files()
+        self.mount_a.umount_wait()
+
+        self.mount_b.check_files()
+
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        # Check that the admin socket interface is correctly reporting
+        # two sessions
+        # =====================================================
+        ls_data = self._session_list()
+        self.assert_session_count(2, ls_data)
+
+        self.assertSetEqual(
+            set([l['id'] for l in ls_data]),
+            {self.mount_a.get_global_id(), self.mount_b.get_global_id()}
+        )
+
+    def test_restart(self):
+        # Check that after an MDS restart both clients reconnect and continue
+        # to handle I/O
+        # =====================================================
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_state('up:active', timeout=MDS_RESTART_GRACE)
+
+        self.mount_a.create_destroy()
+        self.mount_b.create_destroy()
+
+    def _session_num_caps(self, client_id):
+        ls_data = self.fs.mds_asok(['session', 'ls'])
+        return int(self._session_by_id(ls_data).get(client_id, {'num_caps': None})['num_caps'])
+
+    def test_reconnect_timeout(self):
+        # Reconnect timeout
+        # =================
+        # Check that if I stop an MDS and a client goes away, the MDS waits
+        # for the reconnect period
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        mount_a_client_id = self.mount_a.get_global_id()
+        self.mount_a.umount_wait(force=True)
+
+        self.fs.mds_restart()
+
+        self.fs.wait_for_state('up:reconnect', reject='up:active', timeout=MDS_RESTART_GRACE)
+        # Check that the MDS locally reports its state correctly
+        status = self.fs.mds_asok(['status'])
+        self.assertIn("reconnect_status", status)
+
+        ls_data = self._session_list()
+        self.assert_session_count(2, ls_data)
+
+        # The session for the dead client should have the 'reconnect' flag set
+        self.assertTrue(self.get_session(mount_a_client_id)['reconnecting'])
+
+        # Wait for the reconnect state to clear, this should take the
+        # reconnect timeout period.
+        in_reconnect_for = self.fs.wait_for_state('up:active', timeout=self.mds_reconnect_timeout * 2)
+        # Check that the period we waited to enter active is within a factor
+        # of two of the reconnect timeout.
+        self.assertGreater(in_reconnect_for, self.mds_reconnect_timeout / 2,
+                           "Should have been in reconnect phase for {0} but only took {1}".format(
+                               self.mds_reconnect_timeout, in_reconnect_for
+                           ))
+
+        self.assert_session_count(1)
+
+        # Check that the client that timed out during reconnect can
+        # mount again and do I/O
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        self.mount_a.create_destroy()
+
+        self.assert_session_count(2)
+
+    def test_reconnect_eviction(self):
+        # Eviction during reconnect
+        # =========================
+        mount_a_client_id = self.mount_a.get_global_id()
+
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        # The mount goes away while the MDS is offline
+        self.mount_a.kill()
+
+        self.fs.mds_restart()
+
+        # Enter reconnect phase
+        self.fs.wait_for_state('up:reconnect', reject='up:active', timeout=MDS_RESTART_GRACE)
+        self.assert_session_count(2)
+
+        # Evict the stuck client
+        self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
+        self.assert_session_count(1)
+
+        # Observe that we proceed to active phase without waiting full reconnect timeout
+        evict_til_active = self.fs.wait_for_state('up:active', timeout=MDS_RESTART_GRACE)
+        # Once we evict the troublemaker, the reconnect phase should complete
+        # in well under the reconnect timeout.
+        self.assertLess(evict_til_active, self.mds_reconnect_timeout * 0.5,
+                        "reconnect did not complete soon enough after eviction, took {0}".format(
+                            evict_til_active
+                        ))
+
+        # We killed earlier so must clean up before trying to use again
+        self.mount_a.kill_cleanup()
+
+        # Bring the client back
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        self.mount_a.create_destroy()
+
+    def test_stale_caps(self):
+        # Capability release from stale session
+        # =====================================
+        cap_holder = self.mount_a.open_background()
+
+        # Wait for the file to be visible from another client, indicating
+        # that mount_a has completed its network ops
+        self.mount_b.wait_for_visible()
+
+        # Simulate client death
+        self.mount_a.kill()
+
+        try:
+            # Now, after mds_session_timeout seconds, the waiter should
+            # complete their operation when the MDS marks the holder's
+            # session stale.
+            cap_waiter = self.mount_b.write_background()
+            a = time.time()
+            cap_waiter.wait()
+            b = time.time()
+
+            # Should have succeeded
+            self.assertEqual(cap_waiter.exitstatus, 0)
+
+            cap_waited = b - a
+            log.info("cap_waiter waited {0}s".format(cap_waited))
+            self.assertTrue(self.mds_session_timeout / 2.0 <= cap_waited <= self.mds_session_timeout * 2.0,
+                            "Capability handover took {0}, expected approx {1}".format(
+                                cap_waited, self.mds_session_timeout
+                            ))
+
+            cap_holder.stdin.close()
+            try:
+                cap_holder.wait()
+            except (CommandFailedError, ConnectionLostError):
+                # We killed it (and possibly its node), so it raises an error
+                pass
+        finally:
+            # teardown() doesn't quite handle this case cleanly, so help it out
+            self.mount_a.kill_cleanup()
+
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+    def test_evicted_caps(self):
+        # Eviction while holding a capability
+        # ===================================
+
+        # Take out a write capability on a file on client A,
+        # and then immediately kill it.
+        cap_holder = self.mount_a.open_background()
+        mount_a_client_id = self.mount_a.get_global_id()
+
+        # Wait for the file to be visible from another client, indicating
+        # that mount_a has completed its network ops
+        self.mount_b.wait_for_visible()
+
+        # Simulate client death
+        self.mount_a.kill()
+
+        try:
+            # The waiter should get stuck waiting for the capability
+            # held on the MDS by the now-dead client A
+            cap_waiter = self.mount_b.write_background()
+            time.sleep(5)
+            self.assertFalse(cap_waiter.finished)
+
+            self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
+            # Now, because I evicted the old holder of the capability, it should
+            # immediately get handed over to the waiter
+            a = time.time()
+            cap_waiter.wait()
+            b = time.time()
+            cap_waited = b - a
+            log.info("cap_waiter waited {0}s".format(cap_waited))
+            # This is the check that it happened 'now' rather than waiting
+            # for the session timeout
+            self.assertLess(cap_waited, self.mds_session_timeout / 2.0,
+                            "Capability handover took {0}, expected less than {1}".format(
+                                cap_waited, self.mds_session_timeout / 2.0
+                            ))
+
+            cap_holder.stdin.close()
+            try:
+                cap_holder.wait()
+            except (CommandFailedError, ConnectionLostError):
+                # We killed it (and possibly its node), so it raises an error
+                pass
+        finally:
+            self.mount_a.kill_cleanup()
+
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+    def test_trim_caps(self):
+        # Trim capability when reconnecting MDS
+        # ===================================
+
+        count = 500
+        # Create lots of files
+        for i in range(count):
+            self.mount_a.run_shell(["touch", "f{0}".format(i)])
+
+        # Populate mount_b's cache
+        self.mount_b.run_shell(["ls", "-l"])
+
+        client_id = self.mount_b.get_global_id()
+        num_caps = self._session_num_caps(client_id)
+        self.assertGreaterEqual(num_caps, count)
+
+        # Restart MDS. client should trim its cache when reconnecting to the MDS
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_state('up:active', timeout=MDS_RESTART_GRACE)
+
+        num_caps = self._session_num_caps(client_id)
+        self.assertLess(num_caps, count,
+                        "should have less than {0} capabilities, have {1}".format(
+                            count, num_caps
+                        ))
+
+    def _is_flockable(self):
+        a_version_str = get_package_version(self.mount_a.client_remote, "fuse")
+        b_version_str = get_package_version(self.mount_b.client_remote, "fuse")
+        flock_version_str = "2.9"
+
+        version_regex = re.compile(r"[0-9\.]+")
+        a_result = version_regex.match(a_version_str)
+        self.assertTrue(a_result)
+        b_result = version_regex.match(b_version_str)
+        self.assertTrue(b_result)
+        a_version = version.StrictVersion(a_result.group())
+        b_version = version.StrictVersion(b_result.group())
+        flock_version=version.StrictVersion(flock_version_str)
+
+        if (a_version >= flock_version and b_version >= flock_version):
+            log.info("flock locks are available")
+            return True
+        else:
+            log.info("not testing flock locks, machines have versions {av} and {bv}".format(
+                av=a_version_str,bv=b_version_str))
+            return False
+
+    def test_filelock(self):
+        """
+        Check that file lock doesn't get lost after an MDS restart
+        """
+
+        flockable = self._is_flockable()
+        lock_holder = self.mount_a.lock_background(do_flock=flockable)
+
+        self.mount_b.wait_for_visible("background_file-2")
+        self.mount_b.check_filelock(do_flock=flockable)
+
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_state('up:active', timeout=MDS_RESTART_GRACE)
+
+        self.mount_b.check_filelock(do_flock=flockable)
+
+        # Tear down the background process
+        lock_holder.stdin.close()
+        try:
+            lock_holder.wait()
+        except (CommandFailedError, ConnectionLostError):
+            # We killed it, so it raises an error
+            pass
+
+    def test_filelock_eviction(self):
+        """
+        Check that file lock held by evicted client is given to
+        waiting client.
+        """
+        if not self._is_flockable():
+            self.skipTest("flock is not available")
+
+        lock_holder = self.mount_a.lock_background()
+        self.mount_b.wait_for_visible("background_file-2")
+        self.mount_b.check_filelock()
+
+        lock_taker = self.mount_b.lock_and_release()
+        # Check the taker is waiting (doesn't get it immediately)
+        time.sleep(2)
+        self.assertFalse(lock_holder.finished)
+        self.assertFalse(lock_taker.finished)
+
+        try:
+            mount_a_client_id = self.mount_a.get_global_id()
+            self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
+
+            # Evicting mount_a should let mount_b's attempt to take the lock
+            # succeed
+            self.wait_until_true(lambda: lock_taker.finished, timeout=10)
+        finally:
+            # teardown() doesn't quite handle this case cleanly, so help it out
+            self.mount_a.kill()
+            self.mount_a.kill_cleanup()
+
+        # Bring the client back
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+    def test_dir_fsync(self):
+	self._test_fsync(True);
+
+    def test_create_fsync(self):
+	self._test_fsync(False);
+
+    def _test_fsync(self, dirfsync):
+        """
+        That calls to fsync guarantee visibility of metadata to another
+        client immediately after the fsyncing client dies.
+        """
+
+        # Leave this guy out until he's needed
+        self.mount_b.umount_wait()
+
+        # Create dir + child dentry on client A, and fsync the dir
+        path = os.path.join(self.mount_a.mountpoint, "subdir")
+        self.mount_a.run_python(
+            dedent("""
+                import os
+                import time
+
+                path = "{path}"
+
+                print "Starting creation..."
+                start = time.time()
+
+                os.mkdir(path)
+                dfd = os.open(path, os.O_DIRECTORY)
+
+                fd = open(os.path.join(path, "childfile"), "w")
+                print "Finished creation in {{0}}s".format(time.time() - start)
+
+                print "Starting fsync..."
+                start = time.time()
+                if {dirfsync}:
+                    os.fsync(dfd)
+                else:
+                    os.fsync(fd)
+                print "Finished fsync in {{0}}s".format(time.time() - start)
+            """.format(path=path,dirfsync=str(dirfsync)))
+        )
+
+        # Immediately kill the MDS and then client A
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+        self.mount_a.kill()
+        self.mount_a.kill_cleanup()
+
+        # Restart the MDS.  Wait for it to come up, it'll have to time out in clientreplay
+        self.fs.mds_restart()
+        log.info("Waiting for reconnect...")
+        self.fs.wait_for_state("up:reconnect")
+        log.info("Waiting for active...")
+        self.fs.wait_for_state("up:active", timeout=MDS_RESTART_GRACE + self.mds_reconnect_timeout)
+        log.info("Reached active...")
+
+        # Is the child dentry visible from mount B?
+        self.mount_b.mount()
+        self.mount_b.wait_until_mounted()
+        self.mount_b.run_shell(["ls", "subdir/childfile"])
diff --git a/src/ceph/qa/tasks/cephfs/test_config_commands.py b/src/ceph/qa/tasks/cephfs/test_config_commands.py
new file mode 100644
index 0000000..ce0619f
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_config_commands.py
@@ -0,0 +1,63 @@
+
+from unittest import case
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+from tasks.cephfs.fuse_mount import FuseMount
+
+
+class TestConfigCommands(CephFSTestCase):
+    """
+    Test that daemons and clients respond to the otherwise rarely-used
+    runtime config modification operations.
+    """
+
+    CLIENTS_REQUIRED = 1
+    MDSS_REQUIRED = 1
+
+    def test_client_config(self):
+        """
+        That I can successfully issue asok "config set" commands
+
+        :return:
+        """
+
+        if not isinstance(self.mount_a, FuseMount):
+            raise case.SkipTest("Test only applies to FUSE clients")
+
+        test_key = "client_cache_size"
+        test_val = "123"
+        self.mount_a.admin_socket(['config', 'set', test_key, test_val])
+        out = self.mount_a.admin_socket(['config', 'get', test_key])
+        self.assertEqual(out[test_key], test_val)
+
+        self.mount_a.write_n_mb("file.bin", 1);
+
+        # Implicitly asserting that things don't have lockdep error in shutdown
+        self.mount_a.umount_wait(require_clean=True)
+        self.fs.mds_stop()
+
+    def test_mds_config_asok(self):
+        test_key = "mds_max_purge_ops"
+        test_val = "123"
+        self.fs.mds_asok(['config', 'set', test_key, test_val])
+        out = self.fs.mds_asok(['config', 'get', test_key])
+        self.assertEqual(out[test_key], test_val)
+
+        # Implicitly asserting that things don't have lockdep error in shutdown
+        self.mount_a.umount_wait(require_clean=True)
+        self.fs.mds_stop()
+
+    def test_mds_config_tell(self):
+        test_key = "mds_max_purge_ops"
+        test_val = "123"
+
+        mds_id = self.fs.get_lone_mds_id()
+        self.fs.mon_manager.raw_cluster_cmd("tell", "mds.{0}".format(mds_id), "injectargs",
+                                            "--{0}={1}".format(test_key, test_val))
+
+        # Read it back with asok because there is no `tell` equivalent
+        out = self.fs.mds_asok(['config', 'get', test_key])
+        self.assertEqual(out[test_key], test_val)
+
+        # Implicitly asserting that things don't have lockdep error in shutdown
+        self.mount_a.umount_wait(require_clean=True)
+        self.fs.mds_stop()
diff --git a/src/ceph/qa/tasks/cephfs/test_damage.py b/src/ceph/qa/tasks/cephfs/test_damage.py
new file mode 100644
index 0000000..380b49c
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_damage.py
@@ -0,0 +1,548 @@
+import json
+import logging
+import errno
+import re
+from teuthology.contextutil import MaxWhileTries
+from teuthology.exceptions import CommandFailedError
+from teuthology.orchestra.run import wait
+from tasks.cephfs.fuse_mount import FuseMount
+from tasks.cephfs.cephfs_test_case import CephFSTestCase, for_teuthology
+
+DAMAGED_ON_START = "damaged_on_start"
+DAMAGED_ON_LS = "damaged_on_ls"
+CRASHED = "server crashed"
+NO_DAMAGE = "no damage"
+FAILED_CLIENT = "client failed"
+FAILED_SERVER = "server failed"
+
+# An EIO in response to a stat from the client
+EIO_ON_LS = "eio"
+
+# An EIO, but nothing in damage table (not ever what we expect)
+EIO_NO_DAMAGE = "eio without damage entry"
+
+
+log = logging.getLogger(__name__)
+
+
+class TestDamage(CephFSTestCase):
+    def _simple_workload_write(self):
+        self.mount_a.run_shell(["mkdir", "subdir"])
+        self.mount_a.write_n_mb("subdir/sixmegs", 6)
+        return self.mount_a.stat("subdir/sixmegs")
+
+    def is_marked_damaged(self, rank):
+        mds_map = self.fs.get_mds_map()
+        return rank in mds_map['damaged']
+
+    @for_teuthology #459s
+    def test_object_deletion(self):
+        """
+        That the MDS has a clean 'damaged' response to loss of any single metadata object
+        """
+
+        self._simple_workload_write()
+
+        # Hmm, actually it would be nice to permute whether the metadata pool
+        # state contains sessions or not, but for the moment close this session
+        # to avoid waiting through reconnect on every MDS start.
+        self.mount_a.umount_wait()
+        for mds_name in self.fs.get_active_names():
+            self.fs.mds_asok(["flush", "journal"], mds_name)
+
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        self.fs.rados(['export', '/tmp/metadata.bin'])
+
+        def is_ignored(obj_id, dentry=None):
+            """
+            A filter to avoid redundantly mutating many similar objects (e.g.
+            stray dirfrags) or similar dentries (e.g. stray dir dentries)
+            """
+            if re.match("60.\.00000000", obj_id) and obj_id != "600.00000000":
+                return True
+
+            if dentry and obj_id == "100.00000000":
+                if re.match("stray.+_head", dentry) and dentry != "stray0_head":
+                    return True
+
+            return False
+
+        def get_path(obj_id, dentry=None):
+            """
+            What filesystem path does this object or dentry correspond to?   i.e.
+            what should I poke to see EIO after damaging it?
+            """
+
+            if obj_id == "1.00000000" and dentry == "subdir_head":
+                return "./subdir"
+            elif obj_id == "10000000000.00000000" and dentry == "sixmegs_head":
+                return "./subdir/sixmegs"
+
+            # None means ls will do an "ls -R" in hope of seeing some errors
+            return None
+
+        objects = self.fs.rados(["ls"]).split("\n")
+        objects = [o for o in objects if not is_ignored(o)]
+
+        # Find all objects with an OMAP header
+        omap_header_objs = []
+        for o in objects:
+            header = self.fs.rados(["getomapheader", o])
+            # The rados CLI wraps the header output in a hex-printed style
+            header_bytes = int(re.match("header \((.+) bytes\)", header).group(1))
+            if header_bytes > 0:
+                omap_header_objs.append(o)
+
+        # Find all OMAP key/vals
+        omap_keys = []
+        for o in objects:
+            keys_str = self.fs.rados(["listomapkeys", o])
+            if keys_str:
+                for key in keys_str.split("\n"):
+                    if not is_ignored(o, key):
+                        omap_keys.append((o, key))
+
+        # Find objects that have data in their bodies
+        data_objects = []
+        for obj_id in objects:
+            stat_out = self.fs.rados(["stat", obj_id])
+            size = int(re.match(".+, size (.+)$", stat_out).group(1))
+            if size > 0:
+                data_objects.append(obj_id)
+
+        # Define the various forms of damage we will inflict
+        class MetadataMutation(object):
+            def __init__(self, obj_id_, desc_, mutate_fn_, expectation_, ls_path=None):
+                self.obj_id = obj_id_
+                self.desc = desc_
+                self.mutate_fn = mutate_fn_
+                self.expectation = expectation_
+                if ls_path is None:
+                    self.ls_path = "."
+                else:
+                    self.ls_path = ls_path
+
+            def __eq__(self, other):
+                return self.desc == other.desc
+
+            def __hash__(self):
+                return hash(self.desc)
+
+        junk = "deadbeef" * 10
+        mutations = []
+
+        # Removals
+        for obj_id in objects:
+            if obj_id in [
+                # JournalPointers are auto-replaced if missing (same path as upgrade)
+                "400.00000000",
+                # Missing dirfrags for non-system dirs result in empty directory
+                "10000000000.00000000",
+                # PurgeQueue is auto-created if not found on startup
+                "500.00000000"
+            ]:
+                expectation = NO_DAMAGE
+            else:
+                expectation = DAMAGED_ON_START
+
+            log.info("Expectation on rm '{0}' will be '{1}'".format(
+                obj_id, expectation
+            ))
+
+            mutations.append(MetadataMutation(
+                obj_id,
+                "Delete {0}".format(obj_id),
+                lambda o=obj_id: self.fs.rados(["rm", o]),
+                expectation
+            ))
+
+        # Blatant corruptions
+        mutations.extend([
+            MetadataMutation(
+                o,
+                "Corrupt {0}".format(o),
+                lambda o=o: self.fs.rados(["put", o, "-"], stdin_data=junk),
+                DAMAGED_ON_START
+            ) for o in data_objects
+        ])
+
+        # Truncations
+        for obj_id in data_objects:
+            if obj_id == "500.00000000":
+                # The PurgeQueue is allowed to be empty: Journaler interprets
+                # an empty header object as an empty journal.
+                expectation = NO_DAMAGE
+            else:
+                expectation = DAMAGED_ON_START
+
+            mutations.append(
+                MetadataMutation(
+                    o,
+                    "Truncate {0}".format(o),
+                    lambda o=o: self.fs.rados(["truncate", o, "0"]),
+                    DAMAGED_ON_START
+            ))
+
+        # OMAP value corruptions
+        for o, k in omap_keys:
+            if o.startswith("100."):
+                # Anything in rank 0's 'mydir'
+                expectation = DAMAGED_ON_START
+            else:
+                expectation = EIO_ON_LS
+
+            mutations.append(
+                MetadataMutation(
+                    o,
+                    "Corrupt omap key {0}:{1}".format(o, k),
+                    lambda o=o,k=k: self.fs.rados(["setomapval", o, k, junk]),
+                    expectation,
+                    get_path(o, k)
+                )
+            )
+
+        # OMAP header corruptions
+        for obj_id in omap_header_objs:
+            if re.match("60.\.00000000", obj_id) \
+                    or obj_id in ["1.00000000", "100.00000000", "mds0_sessionmap"]:
+                expectation = DAMAGED_ON_START
+            else:
+                expectation = NO_DAMAGE
+
+            log.info("Expectation on corrupt header '{0}' will be '{1}'".format(
+                obj_id, expectation
+            ))
+
+            mutations.append(
+                MetadataMutation(
+                    obj_id,
+                    "Corrupt omap header on {0}".format(obj_id),
+                    lambda o=obj_id: self.fs.rados(["setomapheader", o, junk]),
+                    expectation
+                )
+            )
+
+        results = {}
+
+        for mutation in mutations:
+            log.info("Applying mutation '{0}'".format(mutation.desc))
+
+            # Reset MDS state
+            self.mount_a.umount_wait(force=True)
+            self.fs.mds_stop()
+            self.fs.mds_fail()
+            self.fs.mon_manager.raw_cluster_cmd('mds', 'repaired', '0')
+
+            # Reset RADOS pool state
+            self.fs.rados(['import', '/tmp/metadata.bin'])
+
+            # Inject the mutation
+            mutation.mutate_fn()
+
+            # Try starting the MDS
+            self.fs.mds_restart()
+
+            # How long we'll wait between starting a daemon and expecting
+            # it to make it through startup, and potentially declare itself
+            # damaged to the mon cluster.
+            startup_timeout = 60
+
+            if mutation.expectation not in (EIO_ON_LS, DAMAGED_ON_LS, NO_DAMAGE):
+                if mutation.expectation == DAMAGED_ON_START:
+                    # The MDS may pass through active before making it to damaged
+                    try:
+                        self.wait_until_true(lambda: self.is_marked_damaged(0), startup_timeout)
+                    except RuntimeError:
+                        pass
+
+                # Wait for MDS to either come up or go into damaged state
+                try:
+                    self.wait_until_true(lambda: self.is_marked_damaged(0) or self.fs.are_daemons_healthy(), startup_timeout)
+                except RuntimeError:
+                    crashed = False
+                    # Didn't make it to healthy or damaged, did it crash?
+                    for daemon_id, daemon in self.fs.mds_daemons.items():
+                        if daemon.proc and daemon.proc.finished:
+                            crashed = True
+                            log.error("Daemon {0} crashed!".format(daemon_id))
+                            daemon.proc = None  # So that subsequent stop() doesn't raise error
+                    if not crashed:
+                        # Didn't go health, didn't go damaged, didn't crash, so what?
+                        raise
+                    else:
+                        log.info("Result: Mutation '{0}' led to crash".format(mutation.desc))
+                        results[mutation] = CRASHED
+                        continue
+                if self.is_marked_damaged(0):
+                    log.info("Result: Mutation '{0}' led to DAMAGED state".format(mutation.desc))
+                    results[mutation] = DAMAGED_ON_START
+                    continue
+                else:
+                    log.info("Mutation '{0}' did not prevent MDS startup, attempting ls...".format(mutation.desc))
+            else:
+                try:
+                    self.wait_until_true(self.fs.are_daemons_healthy, 60)
+                except RuntimeError:
+                    log.info("Result: Mutation '{0}' should have left us healthy, actually not.".format(mutation.desc))
+                    if self.is_marked_damaged(0):
+                        results[mutation] = DAMAGED_ON_START
+                    else:
+                        results[mutation] = FAILED_SERVER
+                    continue
+                log.info("Daemons came up after mutation '{0}', proceeding to ls".format(mutation.desc))
+
+            # MDS is up, should go damaged on ls or client mount
+            self.mount_a.mount()
+            self.mount_a.wait_until_mounted()
+            if mutation.ls_path == ".":
+                proc = self.mount_a.run_shell(["ls", "-R", mutation.ls_path], wait=False)
+            else:
+                proc = self.mount_a.stat(mutation.ls_path, wait=False)
+
+            if mutation.expectation == DAMAGED_ON_LS:
+                try:
+                    self.wait_until_true(lambda: self.is_marked_damaged(0), 60)
+                    log.info("Result: Mutation '{0}' led to DAMAGED state after ls".format(mutation.desc))
+                    results[mutation] = DAMAGED_ON_LS
+                except RuntimeError:
+                    if self.fs.are_daemons_healthy():
+                        log.error("Result: Failed to go damaged on mutation '{0}', actually went active".format(
+                            mutation.desc))
+                        results[mutation] = NO_DAMAGE
+                    else:
+                        log.error("Result: Failed to go damaged on mutation '{0}'".format(mutation.desc))
+                        results[mutation] = FAILED_SERVER
+
+            else:
+                try:
+                    wait([proc], 20)
+                    log.info("Result: Mutation '{0}' did not caused DAMAGED state".format(mutation.desc))
+                    results[mutation] = NO_DAMAGE
+                except MaxWhileTries:
+                    log.info("Result: Failed to complete client IO on mutation '{0}'".format(mutation.desc))
+                    results[mutation] = FAILED_CLIENT
+                except CommandFailedError as e:
+                    if e.exitstatus == errno.EIO:
+                        log.info("Result: EIO on client")
+                        results[mutation] = EIO_ON_LS
+                    else:
+                        log.info("Result: unexpected error {0} on client".format(e))
+                        results[mutation] = FAILED_CLIENT
+
+            if mutation.expectation == EIO_ON_LS:
+                # EIOs mean something handled by DamageTable: assert that it has
+                # been populated
+                damage = json.loads(
+                    self.fs.mon_manager.raw_cluster_cmd(
+                        'tell', 'mds.{0}'.format(self.fs.get_active_names()[0]), "damage", "ls", '--format=json-pretty'))
+                if len(damage) == 0:
+                    results[mutation] = EIO_NO_DAMAGE
+
+        failures = [(mutation, result) for (mutation, result) in results.items() if mutation.expectation != result]
+        if failures:
+            log.error("{0} mutations had unexpected outcomes:".format(len(failures)))
+            for mutation, result in failures:
+                log.error("  Expected '{0}' actually '{1}' from '{2}'".format(
+                    mutation.expectation, result, mutation.desc
+                ))
+            raise RuntimeError("{0} mutations had unexpected outcomes".format(len(failures)))
+        else:
+            log.info("All {0} mutations had expected outcomes".format(len(mutations)))
+
+    def test_damaged_dentry(self):
+        # Damage to dentrys is interesting because it leaves the
+        # directory's `complete` flag in a subtle state where
+        # we have marked the dir complete in order that folks
+        # can access it, but in actual fact there is a dentry
+        # missing
+        self.mount_a.run_shell(["mkdir", "subdir/"])
+
+        self.mount_a.run_shell(["touch", "subdir/file_undamaged"])
+        self.mount_a.run_shell(["touch", "subdir/file_to_be_damaged"])
+
+        subdir_ino = self.mount_a.path_to_ino("subdir")
+
+        self.mount_a.umount_wait()
+        for mds_name in self.fs.get_active_names():
+            self.fs.mds_asok(["flush", "journal"], mds_name)
+
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        # Corrupt a dentry
+        junk = "deadbeef" * 10
+        dirfrag_obj = "{0:x}.00000000".format(subdir_ino)
+        self.fs.rados(["setomapval", dirfrag_obj, "file_to_be_damaged_head", junk])
+
+        # Start up and try to list it
+        self.fs.mds_restart()
+        self.fs.wait_for_daemons()
+
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        dentries = self.mount_a.ls("subdir/")
+
+        # The damaged guy should have disappeared
+        self.assertEqual(dentries, ["file_undamaged"])
+
+        # I should get ENOENT if I try and read it normally, because
+        # the dir is considered complete
+        try:
+            self.mount_a.stat("subdir/file_to_be_damaged", wait=True)
+        except CommandFailedError as e:
+            self.assertEqual(e.exitstatus, errno.ENOENT)
+        else:
+            raise AssertionError("Expected ENOENT")
+
+        # The fact that there is damaged should have bee recorded
+        damage = json.loads(
+            self.fs.mon_manager.raw_cluster_cmd(
+                'tell', 'mds.{0}'.format(self.fs.get_active_names()[0]),
+                "damage", "ls", '--format=json-pretty'))
+        self.assertEqual(len(damage), 1)
+        damage_id = damage[0]['id']
+
+        # If I try to create a dentry with the same name as the damaged guy
+        # then that should be forbidden
+        try:
+            self.mount_a.touch("subdir/file_to_be_damaged")
+        except CommandFailedError as e:
+            self.assertEqual(e.exitstatus, errno.EIO)
+        else:
+            raise AssertionError("Expected EIO")
+
+        # Attempting that touch will clear the client's complete flag, now
+        # when I stat it I'll get EIO instead of ENOENT
+        try:
+            self.mount_a.stat("subdir/file_to_be_damaged", wait=True)
+        except CommandFailedError as e:
+            if isinstance(self.mount_a, FuseMount):
+                self.assertEqual(e.exitstatus, errno.EIO)
+            else:
+                # Kernel client handles this case differently
+                self.assertEqual(e.exitstatus, errno.ENOENT)
+        else:
+            raise AssertionError("Expected EIO")
+
+        nfiles = self.mount_a.getfattr("./subdir", "ceph.dir.files")
+        self.assertEqual(nfiles, "2")
+
+        self.mount_a.umount_wait()
+
+        # Now repair the stats
+        scrub_json = self.fs.mds_asok(["scrub_path", "/subdir", "repair"])
+        log.info(json.dumps(scrub_json, indent=2))
+
+        self.assertEqual(scrub_json["passed_validation"], False)
+        self.assertEqual(scrub_json["raw_stats"]["checked"], True)
+        self.assertEqual(scrub_json["raw_stats"]["passed"], False)
+
+        # Check that the file count is now correct
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        nfiles = self.mount_a.getfattr("./subdir", "ceph.dir.files")
+        self.assertEqual(nfiles, "1")
+
+        # Clean up the omap object
+        self.fs.rados(["setomapval", dirfrag_obj, "file_to_be_damaged_head", junk])
+
+        # Clean up the damagetable entry
+        self.fs.mon_manager.raw_cluster_cmd(
+            'tell', 'mds.{0}'.format(self.fs.get_active_names()[0]),
+            "damage", "rm", "{did}".format(did=damage_id))
+
+        # Now I should be able to create a file with the same name as the
+        # damaged guy if I want.
+        self.mount_a.touch("subdir/file_to_be_damaged")
+
+    def test_open_ino_errors(self):
+        """
+        That errors encountered during opening inos are properly propagated
+        """
+
+        self.mount_a.run_shell(["mkdir", "dir1"])
+        self.mount_a.run_shell(["touch", "dir1/file1"])
+        self.mount_a.run_shell(["mkdir", "dir2"])
+        self.mount_a.run_shell(["touch", "dir2/file2"])
+        self.mount_a.run_shell(["mkdir", "testdir"])
+        self.mount_a.run_shell(["ln", "dir1/file1", "testdir/hardlink1"])
+        self.mount_a.run_shell(["ln", "dir2/file2", "testdir/hardlink2"])
+
+        file1_ino = self.mount_a.path_to_ino("dir1/file1")
+        file2_ino = self.mount_a.path_to_ino("dir2/file2")
+        dir2_ino = self.mount_a.path_to_ino("dir2")
+
+        # Ensure everything is written to backing store
+        self.mount_a.umount_wait()
+        self.fs.mds_asok(["flush", "journal"])
+
+        # Drop everything from the MDS cache
+        self.mds_cluster.mds_stop()
+        self.fs.journal_tool(['journal', 'reset'])
+        self.mds_cluster.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        self.mount_a.mount()
+
+        # Case 1: un-decodeable backtrace
+
+        # Validate that the backtrace is present and decodable
+        self.fs.read_backtrace(file1_ino)
+        # Go corrupt the backtrace of alpha/target (used for resolving
+        # bravo/hardlink).
+        self.fs._write_data_xattr(file1_ino, "parent", "rhubarb")
+
+        # Check that touching the hardlink gives EIO
+        ran = self.mount_a.run_shell(["stat", "testdir/hardlink1"], wait=False)
+        try:
+            ran.wait()
+        except CommandFailedError:
+            self.assertTrue("Input/output error" in ran.stderr.getvalue())
+
+        # Check that an entry is created in the damage table
+        damage = json.loads(
+            self.fs.mon_manager.raw_cluster_cmd(
+                'tell', 'mds.{0}'.format(self.fs.get_active_names()[0]),
+                "damage", "ls", '--format=json-pretty'))
+        self.assertEqual(len(damage), 1)
+        self.assertEqual(damage[0]['damage_type'], "backtrace")
+        self.assertEqual(damage[0]['ino'], file1_ino)
+
+        self.fs.mon_manager.raw_cluster_cmd(
+            'tell', 'mds.{0}'.format(self.fs.get_active_names()[0]),
+            "damage", "rm", str(damage[0]['id']))
+
+
+        # Case 2: missing dirfrag for the target inode
+
+        self.fs.rados(["rm", "{0:x}.00000000".format(dir2_ino)])
+
+        # Check that touching the hardlink gives EIO
+        ran = self.mount_a.run_shell(["stat", "testdir/hardlink2"], wait=False)
+        try:
+            ran.wait()
+        except CommandFailedError:
+            self.assertTrue("Input/output error" in ran.stderr.getvalue())
+
+        # Check that an entry is created in the damage table
+        damage = json.loads(
+            self.fs.mon_manager.raw_cluster_cmd(
+                'tell', 'mds.{0}'.format(self.fs.get_active_names()[0]),
+                "damage", "ls", '--format=json-pretty'))
+        self.assertEqual(len(damage), 2)
+        if damage[0]['damage_type'] == "backtrace" :
+            self.assertEqual(damage[0]['ino'], file2_ino)
+            self.assertEqual(damage[1]['damage_type'], "dir_frag")
+            self.assertEqual(damage[1]['ino'], dir2_ino)
+        else:
+            self.assertEqual(damage[0]['damage_type'], "dir_frag")
+            self.assertEqual(damage[0]['ino'], dir2_ino)
+            self.assertEqual(damage[1]['damage_type'], "backtrace")
+            self.assertEqual(damage[1]['ino'], file2_ino)
+
+        for entry in damage:
+            self.fs.mon_manager.raw_cluster_cmd(
+                'tell', 'mds.{0}'.format(self.fs.get_active_names()[0]),
+                "damage", "rm", str(entry['id']))
diff --git a/src/ceph/qa/tasks/cephfs/test_data_scan.py b/src/ceph/qa/tasks/cephfs/test_data_scan.py
new file mode 100644
index 0000000..a2d3157
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_data_scan.py
@@ -0,0 +1,600 @@
+
+"""
+Test our tools for recovering metadata from the data pool
+"""
+import json
+
+import logging
+import os
+from textwrap import dedent
+import traceback
+from collections import namedtuple, defaultdict
+
+from teuthology.orchestra.run import CommandFailedError
+from tasks.cephfs.cephfs_test_case import CephFSTestCase, for_teuthology
+
+log = logging.getLogger(__name__)
+
+
+ValidationError = namedtuple("ValidationError", ["exception", "backtrace"])
+
+
+class Workload(object):
+    def __init__(self, filesystem, mount):
+        self._mount = mount
+        self._filesystem = filesystem
+        self._initial_state = None
+
+        # Accumulate backtraces for every failed validation, and return them.  Backtraces
+        # are rather verbose, but we only see them when something breaks, and they
+        # let us see which check failed without having to decorate each check with
+        # a string
+        self._errors = []
+
+    def assert_equal(self, a, b):
+        try:
+            if a != b:
+                raise AssertionError("{0} != {1}".format(a, b))
+        except AssertionError as e:
+            self._errors.append(
+                ValidationError(e, traceback.format_exc(3))
+            )
+
+    def write(self):
+        """
+        Write the workload files to the mount
+        """
+        raise NotImplementedError()
+
+    def validate(self):
+        """
+        Read from the mount and validate that the workload files are present (i.e. have
+        survived or been reconstructed from the test scenario)
+        """
+        raise NotImplementedError()
+
+    def damage(self):
+        """
+        Damage the filesystem pools in ways that will be interesting to recover from.  By
+        default just wipe everything in the metadata pool
+        """
+        # Delete every object in the metadata pool
+        objects = self._filesystem.rados(["ls"]).split("\n")
+        for o in objects:
+            self._filesystem.rados(["rm", o])
+
+    def flush(self):
+        """
+        Called after client unmount, after write: flush whatever you want
+        """
+        self._filesystem.mds_asok(["flush", "journal"])
+
+
+class SimpleWorkload(Workload):
+    """
+    Single file, single directory, check that it gets recovered and so does its size
+    """
+    def write(self):
+        self._mount.run_shell(["mkdir", "subdir"])
+        self._mount.write_n_mb("subdir/sixmegs", 6)
+        self._initial_state = self._mount.stat("subdir/sixmegs")
+
+    def validate(self):
+        self._mount.run_shell(["ls", "subdir"])
+        st = self._mount.stat("subdir/sixmegs")
+        self.assert_equal(st['st_size'], self._initial_state['st_size'])
+        return self._errors
+
+
+class MovedFile(Workload):
+    def write(self):
+        # Create a file whose backtrace disagrees with his eventual position
+        # in the metadata.  We will see that he gets reconstructed in his
+        # original position according to his backtrace.
+        self._mount.run_shell(["mkdir", "subdir_alpha"])
+        self._mount.run_shell(["mkdir", "subdir_bravo"])
+        self._mount.write_n_mb("subdir_alpha/sixmegs", 6)
+        self._filesystem.mds_asok(["flush", "journal"])
+        self._mount.run_shell(["mv", "subdir_alpha/sixmegs", "subdir_bravo/sixmegs"])
+        self._initial_state = self._mount.stat("subdir_bravo/sixmegs")
+
+    def flush(self):
+        pass
+
+    def validate(self):
+        self.assert_equal(self._mount.ls(), ["subdir_alpha"])
+        st = self._mount.stat("subdir_alpha/sixmegs")
+        self.assert_equal(st['st_size'], self._initial_state['st_size'])
+        return self._errors
+
+
+class BacktracelessFile(Workload):
+    def write(self):
+        self._mount.run_shell(["mkdir", "subdir"])
+        self._mount.write_n_mb("subdir/sixmegs", 6)
+        self._initial_state = self._mount.stat("subdir/sixmegs")
+
+    def flush(self):
+        # Never flush metadata, so backtrace won't be written
+        pass
+
+    def validate(self):
+        ino_name = "%x" % self._initial_state["st_ino"]
+
+        # The inode should be linked into lost+found because we had no path for it
+        self.assert_equal(self._mount.ls(), ["lost+found"])
+        self.assert_equal(self._mount.ls("lost+found"), [ino_name])
+        st = self._mount.stat("lost+found/{ino_name}".format(ino_name=ino_name))
+
+        # We might not have got the name or path, but we should still get the size
+        self.assert_equal(st['st_size'], self._initial_state['st_size'])
+
+        return self._errors
+
+
+class StripedStashedLayout(Workload):
+    def __init__(self, fs, m):
+        super(StripedStashedLayout, self).__init__(fs, m)
+
+        # Nice small stripes so we can quickly do our writes+validates
+        self.sc = 4
+        self.ss = 65536
+        self.os = 262144
+
+        self.interesting_sizes = [
+            # Exactly stripe_count objects will exist
+            self.os * self.sc,
+            # Fewer than stripe_count objects will exist
+            self.os * self.sc / 2,
+            self.os * (self.sc - 1) + self.os / 2,
+            self.os * (self.sc - 1) + self.os / 2 - 1,
+            self.os * (self.sc + 1) + self.os / 2,
+            self.os * (self.sc + 1) + self.os / 2 + 1,
+            # More than stripe_count objects will exist
+            self.os * self.sc + self.os * self.sc / 2
+        ]
+
+    def write(self):
+        # Create a dir with a striped layout set on it
+        self._mount.run_shell(["mkdir", "stripey"])
+
+        self._mount.setfattr("./stripey", "ceph.dir.layout",
+             "stripe_unit={ss} stripe_count={sc} object_size={os} pool={pool}".format(
+                 ss=self.ss, os=self.os, sc=self.sc,
+                 pool=self._filesystem.get_data_pool_name()
+             ))
+
+        # Write files, then flush metadata so that its layout gets written into an xattr
+        for i, n_bytes in enumerate(self.interesting_sizes):
+            self._mount.write_test_pattern("stripey/flushed_file_{0}".format(i), n_bytes)
+            # This is really just validating the validator
+            self._mount.validate_test_pattern("stripey/flushed_file_{0}".format(i), n_bytes)
+        self._filesystem.mds_asok(["flush", "journal"])
+
+        # Write another file in the same way, but this time don't flush the metadata,
+        # so that it won't have the layout xattr
+        self._mount.write_test_pattern("stripey/unflushed_file", 1024 * 512)
+        self._mount.validate_test_pattern("stripey/unflushed_file", 1024 * 512)
+
+        self._initial_state = {
+            "unflushed_ino": self._mount.path_to_ino("stripey/unflushed_file")
+        }
+
+    def flush(self):
+        # Pass because we already selectively flushed during write
+        pass
+
+    def validate(self):
+        # The first files should have been recovered into its original location
+        # with the correct layout: read back correct data
+        for i, n_bytes in enumerate(self.interesting_sizes):
+            try:
+                self._mount.validate_test_pattern("stripey/flushed_file_{0}".format(i), n_bytes)
+            except CommandFailedError as e:
+                self._errors.append(
+                    ValidationError("File {0} (size {1}): {2}".format(i, n_bytes, e), traceback.format_exc(3))
+                )
+
+        # The unflushed file should have been recovered into lost+found without
+        # the correct layout: read back junk
+        ino_name = "%x" % self._initial_state["unflushed_ino"]
+        self.assert_equal(self._mount.ls("lost+found"), [ino_name])
+        try:
+            self._mount.validate_test_pattern(os.path.join("lost+found", ino_name), 1024 * 512)
+        except CommandFailedError:
+            pass
+        else:
+            self._errors.append(
+                ValidationError("Unexpectedly valid data in unflushed striped file", "")
+            )
+
+        return self._errors
+
+
+class ManyFilesWorkload(Workload):
+    def __init__(self, filesystem, mount, file_count):
+        super(ManyFilesWorkload, self).__init__(filesystem, mount)
+        self.file_count = file_count
+
+    def write(self):
+        self._mount.run_shell(["mkdir", "subdir"])
+        for n in range(0, self.file_count):
+            self._mount.write_test_pattern("subdir/{0}".format(n), 6 * 1024 * 1024)
+
+    def validate(self):
+        for n in range(0, self.file_count):
+            try:
+                self._mount.validate_test_pattern("subdir/{0}".format(n), 6 * 1024 * 1024)
+            except CommandFailedError as e:
+                self._errors.append(
+                    ValidationError("File {0}: {1}".format(n, e), traceback.format_exc(3))
+                )
+
+        return self._errors
+
+
+class MovedDir(Workload):
+    def write(self):
+        # Create a nested dir that we will then move.  Two files with two different
+        # backtraces referring to the moved dir, claiming two different locations for
+        # it.  We will see that only one backtrace wins and the dir ends up with
+        # single linkage.
+        self._mount.run_shell(["mkdir", "-p", "grandmother/parent"])
+        self._mount.write_n_mb("grandmother/parent/orig_pos_file", 1)
+        self._filesystem.mds_asok(["flush", "journal"])
+        self._mount.run_shell(["mkdir", "grandfather"])
+        self._mount.run_shell(["mv", "grandmother/parent", "grandfather"])
+        self._mount.write_n_mb("grandfather/parent/new_pos_file", 2)
+        self._filesystem.mds_asok(["flush", "journal"])
+
+        self._initial_state = (
+            self._mount.stat("grandfather/parent/orig_pos_file"),
+            self._mount.stat("grandfather/parent/new_pos_file")
+        )
+
+    def validate(self):
+        root_files = self._mount.ls()
+        self.assert_equal(len(root_files), 1)
+        self.assert_equal(root_files[0] in ["grandfather", "grandmother"], True)
+        winner = root_files[0]
+        st_opf = self._mount.stat("{0}/parent/orig_pos_file".format(winner))
+        st_npf = self._mount.stat("{0}/parent/new_pos_file".format(winner))
+
+        self.assert_equal(st_opf['st_size'], self._initial_state[0]['st_size'])
+        self.assert_equal(st_npf['st_size'], self._initial_state[1]['st_size'])
+
+
+class MissingZerothObject(Workload):
+    def write(self):
+        self._mount.run_shell(["mkdir", "subdir"])
+        self._mount.write_n_mb("subdir/sixmegs", 6)
+        self._initial_state = self._mount.stat("subdir/sixmegs")
+
+    def damage(self):
+        super(MissingZerothObject, self).damage()
+        zeroth_id = "{0:x}.00000000".format(self._initial_state['st_ino'])
+        self._filesystem.rados(["rm", zeroth_id], pool=self._filesystem.get_data_pool_name())
+
+    def validate(self):
+        st = self._mount.stat("lost+found/{0:x}".format(self._initial_state['st_ino']))
+        self.assert_equal(st['st_size'], self._initial_state['st_size'])
+
+
+class NonDefaultLayout(Workload):
+    """
+    Check that the reconstruction copes with files that have a different
+    object size in their layout
+    """
+    def write(self):
+        self._mount.run_shell(["touch", "datafile"])
+        self._mount.setfattr("./datafile", "ceph.file.layout.object_size", "8388608")
+        self._mount.run_shell(["dd", "if=/dev/urandom", "of=./datafile", "bs=1M", "count=32"])
+        self._initial_state = self._mount.stat("datafile")
+
+    def validate(self):
+        # Check we got the layout reconstructed properly
+        object_size = int(self._mount.getfattr(
+            "./datafile", "ceph.file.layout.object_size"))
+        self.assert_equal(object_size, 8388608)
+
+        # Check we got the file size reconstructed properly
+        st = self._mount.stat("datafile")
+        self.assert_equal(st['st_size'], self._initial_state['st_size'])
+
+
+class TestDataScan(CephFSTestCase):
+    MDSS_REQUIRED = 2
+
+    def is_marked_damaged(self, rank):
+        mds_map = self.fs.get_mds_map()
+        return rank in mds_map['damaged']
+
+    def _rebuild_metadata(self, workload, workers=1):
+        """
+        That when all objects in metadata pool are removed, we can rebuild a metadata pool
+        based on the contents of a data pool, and a client can see and read our files.
+        """
+
+        # First, inject some files
+
+        workload.write()
+
+        # Unmount the client and flush the journal: the tool should also cope with
+        # situations where there is dirty metadata, but we'll test that separately
+        self.mount_a.umount_wait()
+        workload.flush()
+
+        # Stop the MDS
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        # After recovery, we need the MDS to not be strict about stats (in production these options
+        # are off by default, but in QA we need to explicitly disable them)
+        self.fs.set_ceph_conf('mds', 'mds verify scatter', False)
+        self.fs.set_ceph_conf('mds', 'mds debug scatterstat', False)
+
+        # Apply any data damage the workload wants
+        workload.damage()
+
+        # Reset the MDS map in case multiple ranks were in play: recovery procedure
+        # only understands how to rebuild metadata under rank 0
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'reset', self.fs.name,
+                '--yes-i-really-mean-it')
+
+        self.fs.mds_restart()
+
+        def get_state(mds_id):
+            info = self.mds_cluster.get_mds_info(mds_id)
+            return info['state'] if info is not None else None
+
+        self.wait_until_true(lambda: self.is_marked_damaged(0), 60)
+        for mds_id in self.fs.mds_ids:
+            self.wait_until_equal(
+                    lambda: get_state(mds_id),
+                    "up:standby",
+                    timeout=60)
+
+        self.fs.table_tool([self.fs.name + ":0", "reset", "session"])
+        self.fs.table_tool([self.fs.name + ":0", "reset", "snap"])
+        self.fs.table_tool([self.fs.name + ":0", "reset", "inode"])
+
+        # Run the recovery procedure
+        if False:
+            with self.assertRaises(CommandFailedError):
+                # Normal reset should fail when no objects are present, we'll use --force instead
+                self.fs.journal_tool(["journal", "reset"])
+
+        self.fs.journal_tool(["journal", "reset", "--force"])
+        self.fs.data_scan(["init"])
+        self.fs.data_scan(["scan_extents", self.fs.get_data_pool_name()], worker_count=workers)
+        self.fs.data_scan(["scan_inodes", self.fs.get_data_pool_name()], worker_count=workers)
+
+        # Mark the MDS repaired
+        self.fs.mon_manager.raw_cluster_cmd('mds', 'repaired', '0')
+
+        # Start the MDS
+        self.fs.mds_restart()
+        self.fs.wait_for_daemons()
+        log.info(str(self.mds_cluster.status()))
+
+        # Mount a client
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        # See that the files are present and correct
+        errors = workload.validate()
+        if errors:
+            log.error("Validation errors found: {0}".format(len(errors)))
+            for e in errors:
+                log.error(e.exception)
+                log.error(e.backtrace)
+            raise AssertionError("Validation failed, first error: {0}\n{1}".format(
+                errors[0].exception, errors[0].backtrace
+            ))
+
+    def test_rebuild_simple(self):
+        self._rebuild_metadata(SimpleWorkload(self.fs, self.mount_a))
+
+    def test_rebuild_moved_file(self):
+        self._rebuild_metadata(MovedFile(self.fs, self.mount_a))
+
+    def test_rebuild_backtraceless(self):
+        self._rebuild_metadata(BacktracelessFile(self.fs, self.mount_a))
+
+    def test_rebuild_moved_dir(self):
+        self._rebuild_metadata(MovedDir(self.fs, self.mount_a))
+
+    def test_rebuild_missing_zeroth(self):
+        self._rebuild_metadata(MissingZerothObject(self.fs, self.mount_a))
+
+    def test_rebuild_nondefault_layout(self):
+        self._rebuild_metadata(NonDefaultLayout(self.fs, self.mount_a))
+
+    def test_stashed_layout(self):
+        self._rebuild_metadata(StripedStashedLayout(self.fs, self.mount_a))
+
+    def _dirfrag_keys(self, object_id):
+        keys_str = self.fs.rados(["listomapkeys", object_id])
+        if keys_str:
+            return keys_str.split("\n")
+        else:
+            return []
+
+    def test_fragmented_injection(self):
+        """
+        That when injecting a dentry into a fragmented directory, we put it in the right fragment.
+        """
+
+        self.fs.set_allow_dirfrags(True)
+
+        file_count = 100
+        file_names = ["%s" % n for n in range(0, file_count)]
+
+        # Create a directory of `file_count` files, each named after its
+        # decimal number and containing the string of its decimal number
+        self.mount_a.run_python(dedent("""
+        import os
+        path = os.path.join("{path}", "subdir")
+        os.mkdir(path)
+        for n in range(0, {file_count}):
+            open(os.path.join(path, "%s" % n), 'w').write("%s" % n)
+        """.format(
+            path=self.mount_a.mountpoint,
+            file_count=file_count
+        )))
+
+        dir_ino = self.mount_a.path_to_ino("subdir")
+
+        # Only one MDS should be active!
+        self.assertEqual(len(self.fs.get_active_names()), 1)
+
+        # Ensure that one directory is fragmented
+        mds_id = self.fs.get_active_names()[0]
+        self.fs.mds_asok(["dirfrag", "split", "/subdir", "0/0", "1"], mds_id)
+
+        # Flush journal and stop MDS
+        self.mount_a.umount_wait()
+        self.fs.mds_asok(["flush", "journal"], mds_id)
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        # Pick a dentry and wipe out its key
+        # Because I did a 1 bit split, I know one frag will be named <inode>.01000000
+        frag_obj_id = "{0:x}.01000000".format(dir_ino)
+        keys = self._dirfrag_keys(frag_obj_id)
+        victim_key = keys[7]  # arbitrary choice
+        log.info("victim_key={0}".format(victim_key))
+        victim_dentry = victim_key.split("_head")[0]
+        self.fs.rados(["rmomapkey", frag_obj_id, victim_key])
+
+        # Start filesystem back up, observe that the file appears to be gone in an `ls`
+        self.fs.mds_restart()
+        self.fs.wait_for_daemons()
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        files = self.mount_a.run_shell(["ls", "subdir/"]).stdout.getvalue().strip().split("\n")
+        self.assertListEqual(sorted(files), sorted(list(set(file_names) - set([victim_dentry]))))
+
+        # Stop the filesystem
+        self.mount_a.umount_wait()
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        # Run data-scan, observe that it inserts our dentry back into the correct fragment
+        # by checking the omap now has the dentry's key again
+        self.fs.data_scan(["scan_extents", self.fs.get_data_pool_name()])
+        self.fs.data_scan(["scan_inodes", self.fs.get_data_pool_name()])
+        self.assertIn(victim_key, self._dirfrag_keys(frag_obj_id))
+
+        # Start the filesystem and check that the dentry we deleted is now once again visible
+        # and points to the correct file data.
+        self.fs.mds_restart()
+        self.fs.wait_for_daemons()
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        out = self.mount_a.run_shell(["cat", "subdir/{0}".format(victim_dentry)]).stdout.getvalue().strip()
+        self.assertEqual(out, victim_dentry)
+
+        # Finally, close the loop by checking our injected dentry survives a merge
+        mds_id = self.fs.get_active_names()[0]
+        self.mount_a.ls("subdir")  # Do an ls to ensure both frags are in cache so the merge will work
+        self.fs.mds_asok(["dirfrag", "merge", "/subdir", "0/0"], mds_id)
+        self.fs.mds_asok(["flush", "journal"], mds_id)
+        frag_obj_id = "{0:x}.00000000".format(dir_ino)
+        keys = self._dirfrag_keys(frag_obj_id)
+        self.assertListEqual(sorted(keys), sorted(["%s_head" % f for f in file_names]))
+
+    @for_teuthology
+    def test_parallel_execution(self):
+        self._rebuild_metadata(ManyFilesWorkload(self.fs, self.mount_a, 25), workers=7)
+
+    def test_pg_files(self):
+        """
+        That the pg files command tells us which files are associated with
+        a particular PG
+        """
+        file_count = 20
+        self.mount_a.run_shell(["mkdir", "mydir"])
+        self.mount_a.create_n_files("mydir/myfile", file_count)
+
+        # Some files elsewhere in the system that we will ignore
+        # to check that the tool is filtering properly
+        self.mount_a.run_shell(["mkdir", "otherdir"])
+        self.mount_a.create_n_files("otherdir/otherfile", file_count)
+
+        pgs_to_files = defaultdict(list)
+        # Rough (slow) reimplementation of the logic
+        for i in range(0, file_count):
+            file_path = "mydir/myfile_{0}".format(i)
+            ino = self.mount_a.path_to_ino(file_path)
+            obj = "{0:x}.{1:08x}".format(ino, 0)
+            pgid = json.loads(self.fs.mon_manager.raw_cluster_cmd(
+                "osd", "map", self.fs.get_data_pool_name(), obj,
+                "--format=json-pretty"
+            ))['pgid']
+            pgs_to_files[pgid].append(file_path)
+            log.info("{0}: {1}".format(file_path, pgid))
+
+        pg_count = self.fs.get_pgs_per_fs_pool()
+        for pg_n in range(0, pg_count):
+            pg_str = "{0}.{1}".format(self.fs.get_data_pool_id(), pg_n)
+            out = self.fs.data_scan(["pg_files", "mydir", pg_str])
+            lines = [l for l in out.split("\n") if l]
+            log.info("{0}: {1}".format(pg_str, lines))
+            self.assertSetEqual(set(lines), set(pgs_to_files[pg_str]))
+
+    def test_scan_links(self):
+        """
+        The scan_links command fixes linkage errors
+        """
+        self.mount_a.run_shell(["mkdir", "testdir1"])
+        self.mount_a.run_shell(["mkdir", "testdir2"])
+        dir1_ino = self.mount_a.path_to_ino("testdir1")
+        dir2_ino = self.mount_a.path_to_ino("testdir2")
+        dirfrag1_oid = "{0:x}.00000000".format(dir1_ino)
+        dirfrag2_oid = "{0:x}.00000000".format(dir2_ino)
+
+        self.mount_a.run_shell(["touch", "testdir1/file1"])
+        self.mount_a.run_shell(["ln", "testdir1/file1", "testdir1/link1"])
+        self.mount_a.run_shell(["ln", "testdir1/file1", "testdir2/link2"])
+
+        mds_id = self.fs.get_active_names()[0]
+        self.fs.mds_asok(["flush", "journal"], mds_id)
+
+        dirfrag1_keys = self._dirfrag_keys(dirfrag1_oid)
+
+        # introduce duplicated primary link
+        file1_key = "file1_head"
+        self.assertIn(file1_key, dirfrag1_keys)
+        file1_omap_data = self.fs.rados(["getomapval", dirfrag1_oid, file1_key, '-'])
+        self.fs.rados(["setomapval", dirfrag2_oid, file1_key], stdin_data=file1_omap_data)
+        self.assertIn(file1_key, self._dirfrag_keys(dirfrag2_oid))
+
+        # remove a remote link, make inode link count incorrect
+        link1_key = 'link1_head'
+        self.assertIn(link1_key, dirfrag1_keys)
+        self.fs.rados(["rmomapkey", dirfrag1_oid, link1_key])
+
+        # increase good primary link's version
+        self.mount_a.run_shell(["touch", "testdir1/file1"])
+        self.mount_a.umount_wait()
+
+        self.fs.mds_asok(["flush", "journal"], mds_id)
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        # repair linkage errors
+        self.fs.data_scan(["scan_links"])
+
+        # primary link in testdir2 was deleted?
+        self.assertNotIn(file1_key, self._dirfrag_keys(dirfrag2_oid))
+
+        self.fs.mds_restart()
+        self.fs.wait_for_daemons()
+
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        # link count was adjusted?
+        file1_nlink = self.mount_a.path_to_nlink("testdir1/file1")
+        self.assertEqual(file1_nlink, 2)
diff --git a/src/ceph/qa/tasks/cephfs/test_dump_tree.py b/src/ceph/qa/tasks/cephfs/test_dump_tree.py
new file mode 100644
index 0000000..6d943f9
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_dump_tree.py
@@ -0,0 +1,66 @@
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+import random
+import os
+
+class TestDumpTree(CephFSTestCase):
+    def get_paths_to_ino(self):
+        inos = {}
+        p = self.mount_a.run_shell(["find", "./"])
+        paths = p.stdout.getvalue().strip().split()
+        for path in paths:
+            inos[path] = self.mount_a.path_to_ino(path, False)
+
+        return inos
+
+    def populate(self):
+        self.mount_a.run_shell(["git", "clone",
+                                "https://github.com/ceph/ceph-qa-suite"])
+
+    def test_basic(self):
+        self.mount_a.run_shell(["mkdir", "parent"])
+        self.mount_a.run_shell(["mkdir", "parent/child"])
+        self.mount_a.run_shell(["touch", "parent/child/file"])
+        self.mount_a.run_shell(["mkdir", "parent/child/grandchild"])
+        self.mount_a.run_shell(["touch", "parent/child/grandchild/file"])
+
+        inos = self.get_paths_to_ino()
+        tree = self.fs.mds_asok(["dump", "tree", "/parent/child", "1"])
+
+        target_inos = [inos["./parent/child"], inos["./parent/child/file"],
+                       inos["./parent/child/grandchild"]]
+
+        for ino in tree:
+            del target_inos[target_inos.index(ino['ino'])] # don't catch!
+            
+        assert(len(target_inos) == 0)
+
+    def test_random(self):
+        random.seed(0)
+
+        self.populate()
+        inos = self.get_paths_to_ino()
+        target = random.choice(inos.keys())
+
+        if target != "./":
+            target = os.path.dirname(target)
+
+        subtree = [path for path in inos.keys() if path.startswith(target)]
+        target_inos = [inos[path] for path in subtree]
+        tree = self.fs.mds_asok(["dump", "tree", target[1:]])
+
+        for ino in tree:
+            del target_inos[target_inos.index(ino['ino'])] # don't catch!
+            
+        assert(len(target_inos) == 0)
+
+        target_depth = target.count('/')
+        maxdepth = max([path.count('/') for path in subtree]) - target_depth
+        depth = random.randint(0, maxdepth)
+        target_inos = [inos[path] for path in subtree \
+                       if path.count('/') <= depth + target_depth]
+        tree = self.fs.mds_asok(["dump", "tree", target[1:], str(depth)])
+
+        for ino in tree:
+            del target_inos[target_inos.index(ino['ino'])] # don't catch!
+            
+        assert(len(target_inos) == 0)
diff --git a/src/ceph/qa/tasks/cephfs/test_exports.py b/src/ceph/qa/tasks/cephfs/test_exports.py
new file mode 100644
index 0000000..913999d
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_exports.py
@@ -0,0 +1,107 @@
+import logging
+import time
+from tasks.cephfs.fuse_mount import FuseMount
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+
+log = logging.getLogger(__name__)
+
+class TestExports(CephFSTestCase):
+    MDSS_REQUIRED = 2
+
+    def _wait_subtrees(self, status, rank, test):
+        timeout = 30
+        pause = 2
+        test = sorted(test)
+        for i in range(timeout/pause):
+            subtrees = self.fs.mds_asok(["get", "subtrees"], mds_id=status.get_rank(self.fs.id, rank)['name'])
+            subtrees = filter(lambda s: s['dir']['path'].startswith('/'), subtrees)
+            filtered = sorted([(s['dir']['path'], s['auth_first']) for s in subtrees])
+            log.info("%s =?= %s", filtered, test)
+            if filtered == test:
+                # Confirm export_pin in output is correct:
+                for s in subtrees:
+                    self.assertTrue(s['export_pin'] == s['auth_first'])
+                return subtrees
+            time.sleep(pause)
+        raise RuntimeError("rank {0} failed to reach desired subtree state", rank)
+
+    def test_export_pin(self):
+        self.fs.set_max_mds(2)
+        self.fs.wait_for_daemons()
+
+        status = self.fs.status()
+
+        self.mount_a.run_shell(["mkdir", "-p", "1/2/3"])
+        self._wait_subtrees(status, 0, [])
+
+        # NOP
+        self.mount_a.setfattr("1", "ceph.dir.pin", "-1")
+        self._wait_subtrees(status, 0, [])
+
+        # NOP (rank < -1)
+        self.mount_a.setfattr("1", "ceph.dir.pin", "-2341")
+        self._wait_subtrees(status, 0, [])
+
+        # pin /1 to rank 1
+        self.mount_a.setfattr("1", "ceph.dir.pin", "1")
+        self._wait_subtrees(status, 1, [('/1', 1)])
+
+        # Check export_targets is set properly
+        status = self.fs.status()
+        log.info(status)
+        r0 = status.get_rank(self.fs.id, 0)
+        self.assertTrue(sorted(r0['export_targets']) == [1])
+
+        # redundant pin /1/2 to rank 1
+        self.mount_a.setfattr("1/2", "ceph.dir.pin", "1")
+        self._wait_subtrees(status, 1, [('/1', 1), ('/1/2', 1)])
+
+        # change pin /1/2 to rank 0
+        self.mount_a.setfattr("1/2", "ceph.dir.pin", "0")
+        self._wait_subtrees(status, 1, [('/1', 1), ('/1/2', 0)])
+        self._wait_subtrees(status, 0, [('/1', 1), ('/1/2', 0)])
+
+        # change pin /1/2/3 to (presently) non-existent rank 2
+        self.mount_a.setfattr("1/2/3", "ceph.dir.pin", "2")
+        self._wait_subtrees(status, 0, [('/1', 1), ('/1/2', 0)])
+        self._wait_subtrees(status, 1, [('/1', 1), ('/1/2', 0)])
+
+        # change pin /1/2 back to rank 1
+        self.mount_a.setfattr("1/2", "ceph.dir.pin", "1")
+        self._wait_subtrees(status, 1, [('/1', 1), ('/1/2', 1)])
+
+        # add another directory pinned to 1
+        self.mount_a.run_shell(["mkdir", "-p", "1/4/5"])
+        self.mount_a.setfattr("1/4/5", "ceph.dir.pin", "1")
+        self._wait_subtrees(status, 1, [('/1', 1), ('/1/2', 1), ('/1/4/5', 1)])
+
+        # change pin /1 to 0
+        self.mount_a.setfattr("1", "ceph.dir.pin", "0")
+        self._wait_subtrees(status, 0, [('/1', 0), ('/1/2', 1), ('/1/4/5', 1)])
+
+        # change pin /1/2 to default (-1); does the subtree root properly respect it's parent pin?
+        self.mount_a.setfattr("1/2", "ceph.dir.pin", "-1")
+        self._wait_subtrees(status, 0, [('/1', 0), ('/1/4/5', 1)])
+
+        if len(list(status.get_standbys())):
+            self.fs.set_max_mds(3)
+            self.fs.wait_for_state('up:active', rank=2)
+            self._wait_subtrees(status, 0, [('/1', 0), ('/1/4/5', 1), ('/1/2/3', 2)])
+
+            # Check export_targets is set properly
+            status = self.fs.status()
+            log.info(status)
+            r0 = status.get_rank(self.fs.id, 0)
+            self.assertTrue(sorted(r0['export_targets']) == [1,2])
+            r1 = status.get_rank(self.fs.id, 1)
+            self.assertTrue(sorted(r1['export_targets']) == [0])
+            r2 = status.get_rank(self.fs.id, 2)
+            self.assertTrue(sorted(r2['export_targets']) == [])
+
+        # Test rename
+        self.mount_a.run_shell(["mkdir", "-p", "a/b", "aa/bb"])
+        self.mount_a.setfattr("a", "ceph.dir.pin", "1")
+        self.mount_a.setfattr("aa/bb", "ceph.dir.pin", "0")
+        self._wait_subtrees(status, 0, [('/1', 0), ('/1/4/5', 1), ('/1/2/3', 2), ('/a', 1), ('/aa/bb', 0)])
+        self.mount_a.run_shell(["mv", "aa", "a/b/"])
+        self._wait_subtrees(status, 0, [('/1', 0), ('/1/4/5', 1), ('/1/2/3', 2), ('/a', 1), ('/a/b/aa/bb', 0)])
diff --git a/src/ceph/qa/tasks/cephfs/test_failover.py b/src/ceph/qa/tasks/cephfs/test_failover.py
new file mode 100644
index 0000000..9d3392c
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_failover.py
@@ -0,0 +1,645 @@
+import json
+import logging
+from unittest import case, SkipTest
+
+from cephfs_test_case import CephFSTestCase
+from teuthology.exceptions import CommandFailedError
+from teuthology import misc as teuthology
+from tasks.cephfs.fuse_mount import FuseMount
+
+log = logging.getLogger(__name__)
+
+
+class TestFailover(CephFSTestCase):
+    CLIENTS_REQUIRED = 1
+    MDSS_REQUIRED = 2
+
+    def test_simple(self):
+        """
+        That when the active MDS is killed, a standby MDS is promoted into
+        its rank after the grace period.
+
+        This is just a simple unit test, the harder cases are covered
+        in thrashing tests.
+        """
+
+        # Need all my standbys up as well as the active daemons
+        self.wait_for_daemon_start()
+
+        (original_active, ) = self.fs.get_active_names()
+        original_standbys = self.mds_cluster.get_standby_daemons()
+
+        # Kill the rank 0 daemon's physical process
+        self.fs.mds_stop(original_active)
+
+        grace = float(self.fs.get_config("mds_beacon_grace", service_type="mon"))
+
+        # Wait until the monitor promotes his replacement
+        def promoted():
+            active = self.fs.get_active_names()
+            return active and active[0] in original_standbys
+
+        log.info("Waiting for promotion of one of the original standbys {0}".format(
+            original_standbys))
+        self.wait_until_true(
+            promoted,
+            timeout=grace*2)
+
+        # Start the original rank 0 daemon up again, see that he becomes a standby
+        self.fs.mds_restart(original_active)
+        self.wait_until_true(
+            lambda: original_active in self.mds_cluster.get_standby_daemons(),
+            timeout=60  # Approximately long enough for MDS to start and mon to notice
+        )
+
+    def test_client_abort(self):
+        """
+        That a client will respect fuse_require_active_mds and error out
+        when the cluster appears to be unavailable.
+        """
+
+        if not isinstance(self.mount_a, FuseMount):
+            raise SkipTest("Requires FUSE client to inject client metadata")
+
+        require_active = self.fs.get_config("fuse_require_active_mds", service_type="mon").lower() == "true"
+        if not require_active:
+            raise case.SkipTest("fuse_require_active_mds is not set")
+
+        grace = float(self.fs.get_config("mds_beacon_grace", service_type="mon"))
+
+        # Check it's not laggy to begin with
+        (original_active, ) = self.fs.get_active_names()
+        self.assertNotIn("laggy_since", self.fs.mon_manager.get_mds_status(original_active))
+
+        self.mounts[0].umount_wait()
+
+        # Control: that we can mount and unmount usually, while the cluster is healthy
+        self.mounts[0].mount()
+        self.mounts[0].wait_until_mounted()
+        self.mounts[0].umount_wait()
+
+        # Stop the daemon processes
+        self.fs.mds_stop()
+
+        # Wait for everyone to go laggy
+        def laggy():
+            mdsmap = self.fs.get_mds_map()
+            for info in mdsmap['info'].values():
+                if "laggy_since" not in info:
+                    return False
+
+            return True
+
+        self.wait_until_true(laggy, grace * 2)
+        with self.assertRaises(CommandFailedError):
+            self.mounts[0].mount()
+
+    def test_standby_count_wanted(self):
+        """
+        That cluster health warnings are generated by insufficient standbys available.
+        """
+
+        # Need all my standbys up as well as the active daemons
+        self.wait_for_daemon_start()
+
+        grace = float(self.fs.get_config("mds_beacon_grace", service_type="mon"))
+
+        standbys = self.mds_cluster.get_standby_daemons()
+        self.assertGreaterEqual(len(standbys), 1)
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'set', self.fs.name, 'standby_count_wanted', str(len(standbys)))
+
+        # Kill a standby and check for warning
+        victim = standbys.pop()
+        self.fs.mds_stop(victim)
+        log.info("waiting for insufficient standby daemon warning")
+        self.wait_for_health("MDS_INSUFFICIENT_STANDBY", grace*2)
+
+        # restart the standby, see that he becomes a standby, check health clears
+        self.fs.mds_restart(victim)
+        self.wait_until_true(
+            lambda: victim in self.mds_cluster.get_standby_daemons(),
+            timeout=60  # Approximately long enough for MDS to start and mon to notice
+        )
+        self.wait_for_health_clear(timeout=30)
+
+        # Set it one greater than standbys ever seen
+        standbys = self.mds_cluster.get_standby_daemons()
+        self.assertGreaterEqual(len(standbys), 1)
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'set', self.fs.name, 'standby_count_wanted', str(len(standbys)+1))
+        log.info("waiting for insufficient standby daemon warning")
+        self.wait_for_health("MDS_INSUFFICIENT_STANDBY", grace*2)
+
+        # Set it to 0
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'set', self.fs.name, 'standby_count_wanted', '0')
+        self.wait_for_health_clear(timeout=30)
+
+
+
+
+class TestStandbyReplay(CephFSTestCase):
+    MDSS_REQUIRED = 4
+    REQUIRE_FILESYSTEM = False
+
+    def set_standby_for(self, leader, follower, replay):
+        self.set_conf("mds.{0}".format(follower), "mds_standby_for_name", leader)
+        if replay:
+            self.set_conf("mds.{0}".format(follower), "mds_standby_replay", "true")
+
+    def get_info_by_name(self, mds_name):
+        status = self.mds_cluster.status()
+        info = status.get_mds(mds_name)
+        if info is None:
+            log.warn(str(status))
+            raise RuntimeError("MDS '{0}' not found".format(mds_name))
+        else:
+            return info
+
+    def test_standby_replay_unused(self):
+        # Pick out exactly 3 daemons to be run during test
+        use_daemons = sorted(self.mds_cluster.mds_ids[0:3])
+        mds_a, mds_b, mds_c = use_daemons
+        log.info("Using MDS daemons: {0}".format(use_daemons))
+
+        # B and C should both follow A, but only one will
+        # really get into standby replay state.
+        self.set_standby_for(mds_a, mds_b, True)
+        self.set_standby_for(mds_a, mds_c, True)
+
+        # Create FS and start A
+        fs_a = self.mds_cluster.newfs("alpha")
+        self.mds_cluster.mds_restart(mds_a)
+        fs_a.wait_for_daemons()
+        self.assertEqual(fs_a.get_active_names(), [mds_a])
+
+        # Start B, he should go into standby replay
+        self.mds_cluster.mds_restart(mds_b)
+        self.wait_for_daemon_start([mds_b])
+        info_b = self.get_info_by_name(mds_b)
+        self.assertEqual(info_b['state'], "up:standby-replay")
+        self.assertEqual(info_b['standby_for_name'], mds_a)
+        self.assertEqual(info_b['rank'], 0)
+
+        # Start C, he should go into standby (*not* replay)
+        self.mds_cluster.mds_restart(mds_c)
+        self.wait_for_daemon_start([mds_c])
+        info_c = self.get_info_by_name(mds_c)
+        self.assertEqual(info_c['state'], "up:standby")
+        self.assertEqual(info_c['standby_for_name'], mds_a)
+        self.assertEqual(info_c['rank'], -1)
+
+        # Kill B, C should go into standby replay
+        self.mds_cluster.mds_stop(mds_b)
+        self.mds_cluster.mds_fail(mds_b)
+        self.wait_until_equal(
+                lambda: self.get_info_by_name(mds_c)['state'],
+                "up:standby-replay",
+                60)
+        info_c = self.get_info_by_name(mds_c)
+        self.assertEqual(info_c['state'], "up:standby-replay")
+        self.assertEqual(info_c['standby_for_name'], mds_a)
+        self.assertEqual(info_c['rank'], 0)
+
+    def test_standby_failure(self):
+        """
+        That the failure of a standby-replay daemon happens cleanly
+        and doesn't interrupt anything else.
+        """
+        # Pick out exactly 2 daemons to be run during test
+        use_daemons = sorted(self.mds_cluster.mds_ids[0:2])
+        mds_a, mds_b = use_daemons
+        log.info("Using MDS daemons: {0}".format(use_daemons))
+
+        # Configure two pairs of MDSs that are standby for each other
+        self.set_standby_for(mds_a, mds_b, True)
+        self.set_standby_for(mds_b, mds_a, False)
+
+        # Create FS alpha and get mds_a to come up as active
+        fs_a = self.mds_cluster.newfs("alpha")
+        self.mds_cluster.mds_restart(mds_a)
+        fs_a.wait_for_daemons()
+        self.assertEqual(fs_a.get_active_names(), [mds_a])
+
+        # Start the standbys
+        self.mds_cluster.mds_restart(mds_b)
+        self.wait_for_daemon_start([mds_b])
+
+        # See the standby come up as the correct rank
+        info_b = self.get_info_by_name(mds_b)
+        self.assertEqual(info_b['state'], "up:standby-replay")
+        self.assertEqual(info_b['standby_for_name'], mds_a)
+        self.assertEqual(info_b['rank'], 0)
+
+        # Kill the standby
+        self.mds_cluster.mds_stop(mds_b)
+        self.mds_cluster.mds_fail(mds_b)
+
+        # See that the standby is gone and the active remains
+        self.assertEqual(fs_a.get_active_names(), [mds_a])
+        mds_map = fs_a.get_mds_map()
+        self.assertEqual(len(mds_map['info']), 1)
+        self.assertEqual(mds_map['failed'], [])
+        self.assertEqual(mds_map['damaged'], [])
+        self.assertEqual(mds_map['stopped'], [])
+
+    def test_rank_stopped(self):
+        """
+        That when a rank is STOPPED, standby replays for
+        that rank get torn down
+        """
+        # Pick out exactly 2 daemons to be run during test
+        use_daemons = sorted(self.mds_cluster.mds_ids[0:4])
+        mds_a, mds_b, mds_a_s, mds_b_s = use_daemons
+        log.info("Using MDS daemons: {0}".format(use_daemons))
+
+        # a and b both get a standby
+        self.set_standby_for(mds_a, mds_a_s, True)
+        self.set_standby_for(mds_b, mds_b_s, True)
+
+        # Create FS alpha and get mds_a to come up as active
+        fs_a = self.mds_cluster.newfs("alpha")
+        fs_a.set_max_mds(2)
+
+        self.mds_cluster.mds_restart(mds_a)
+        self.wait_until_equal(lambda: fs_a.get_active_names(), [mds_a], 30)
+        self.mds_cluster.mds_restart(mds_b)
+        fs_a.wait_for_daemons()
+        self.assertEqual(sorted(fs_a.get_active_names()), [mds_a, mds_b])
+
+        # Start the standbys
+        self.mds_cluster.mds_restart(mds_b_s)
+        self.wait_for_daemon_start([mds_b_s])
+        self.mds_cluster.mds_restart(mds_a_s)
+        self.wait_for_daemon_start([mds_a_s])
+        info_b_s = self.get_info_by_name(mds_b_s)
+        self.assertEqual(info_b_s['state'], "up:standby-replay")
+        info_a_s = self.get_info_by_name(mds_a_s)
+        self.assertEqual(info_a_s['state'], "up:standby-replay")
+
+        # Shrink the cluster
+        fs_a.set_max_mds(1)
+        fs_a.mon_manager.raw_cluster_cmd("mds", "stop", "{0}:1".format(fs_a.name))
+        self.wait_until_equal(
+            lambda: fs_a.get_active_names(), [mds_a],
+            60
+        )
+
+        # Both 'b' and 'b_s' should go back to being standbys
+        self.wait_until_equal(
+            lambda: self.mds_cluster.get_standby_daemons(), {mds_b, mds_b_s},
+            60
+        )
+
+
+class TestMultiFilesystems(CephFSTestCase):
+    CLIENTS_REQUIRED = 2
+    MDSS_REQUIRED = 4
+
+    # We'll create our own filesystems and start our own daemons
+    REQUIRE_FILESYSTEM = False
+
+    def setUp(self):
+        super(TestMultiFilesystems, self).setUp()
+        self.mds_cluster.mon_manager.raw_cluster_cmd("fs", "flag", "set",
+            "enable_multiple", "true",
+            "--yes-i-really-mean-it")
+
+    def _setup_two(self):
+        fs_a = self.mds_cluster.newfs("alpha")
+        fs_b = self.mds_cluster.newfs("bravo")
+
+        self.mds_cluster.mds_restart()
+
+        # Wait for both filesystems to go healthy
+        fs_a.wait_for_daemons()
+        fs_b.wait_for_daemons()
+
+        # Reconfigure client auth caps
+        for mount in self.mounts:
+            self.mds_cluster.mon_manager.raw_cluster_cmd_result(
+                'auth', 'caps', "client.{0}".format(mount.client_id),
+                'mds', 'allow',
+                'mon', 'allow r',
+                'osd', 'allow rw pool={0}, allow rw pool={1}'.format(
+                    fs_a.get_data_pool_name(), fs_b.get_data_pool_name()))
+
+        return fs_a, fs_b
+
+    def test_clients(self):
+        fs_a, fs_b = self._setup_two()
+
+        # Mount a client on fs_a
+        self.mount_a.mount(mount_fs_name=fs_a.name)
+        self.mount_a.write_n_mb("pad.bin", 1)
+        self.mount_a.write_n_mb("test.bin", 2)
+        a_created_ino = self.mount_a.path_to_ino("test.bin")
+        self.mount_a.create_files()
+
+        # Mount a client on fs_b
+        self.mount_b.mount(mount_fs_name=fs_b.name)
+        self.mount_b.write_n_mb("test.bin", 1)
+        b_created_ino = self.mount_b.path_to_ino("test.bin")
+        self.mount_b.create_files()
+
+        # Check that a non-default filesystem mount survives an MDS
+        # failover (i.e. that map subscription is continuous, not
+        # just the first time), reproduces #16022
+        old_fs_b_mds = fs_b.get_active_names()[0]
+        self.mds_cluster.mds_stop(old_fs_b_mds)
+        self.mds_cluster.mds_fail(old_fs_b_mds)
+        fs_b.wait_for_daemons()
+        background = self.mount_b.write_background()
+        # Raise exception if the write doesn't finish (i.e. if client
+        # has not kept up with MDS failure)
+        try:
+            self.wait_until_true(lambda: background.finished, timeout=30)
+        except RuntimeError:
+            # The mount is stuck, we'll have to force it to fail cleanly
+            background.stdin.close()
+            self.mount_b.umount_wait(force=True)
+            raise
+
+        self.mount_a.umount_wait()
+        self.mount_b.umount_wait()
+
+        # See that the client's files went into the correct pool
+        self.assertTrue(fs_a.data_objects_present(a_created_ino, 1024 * 1024))
+        self.assertTrue(fs_b.data_objects_present(b_created_ino, 1024 * 1024))
+
+    def test_standby(self):
+        fs_a, fs_b = self._setup_two()
+
+        # Assert that the remaining two MDS daemons are now standbys
+        a_daemons = fs_a.get_active_names()
+        b_daemons = fs_b.get_active_names()
+        self.assertEqual(len(a_daemons), 1)
+        self.assertEqual(len(b_daemons), 1)
+        original_a = a_daemons[0]
+        original_b = b_daemons[0]
+        expect_standby_daemons = set(self.mds_cluster.mds_ids) - (set(a_daemons) | set(b_daemons))
+
+        # Need all my standbys up as well as the active daemons
+        self.wait_for_daemon_start()
+        self.assertEqual(expect_standby_daemons, self.mds_cluster.get_standby_daemons())
+
+        # Kill fs_a's active MDS, see a standby take over
+        self.mds_cluster.mds_stop(original_a)
+        self.mds_cluster.mon_manager.raw_cluster_cmd("mds", "fail", original_a)
+        self.wait_until_equal(lambda: len(fs_a.get_active_names()), 1, 30,
+                              reject_fn=lambda v: v > 1)
+        # Assert that it's a *different* daemon that has now appeared in the map for fs_a
+        self.assertNotEqual(fs_a.get_active_names()[0], original_a)
+
+        # Kill fs_b's active MDS, see a standby take over
+        self.mds_cluster.mds_stop(original_b)
+        self.mds_cluster.mon_manager.raw_cluster_cmd("mds", "fail", original_b)
+        self.wait_until_equal(lambda: len(fs_b.get_active_names()), 1, 30,
+                              reject_fn=lambda v: v > 1)
+        # Assert that it's a *different* daemon that has now appeared in the map for fs_a
+        self.assertNotEqual(fs_b.get_active_names()[0], original_b)
+
+        # Both of the original active daemons should be gone, and all standbys used up
+        self.assertEqual(self.mds_cluster.get_standby_daemons(), set())
+
+        # Restart the ones I killed, see them reappear as standbys
+        self.mds_cluster.mds_restart(original_a)
+        self.mds_cluster.mds_restart(original_b)
+        self.wait_until_true(
+            lambda: {original_a, original_b} == self.mds_cluster.get_standby_daemons(),
+            timeout=30
+        )
+
+    def test_grow_shrink(self):
+        # Usual setup...
+        fs_a, fs_b = self._setup_two()
+
+        # Increase max_mds on fs_b, see a standby take up the role
+        fs_b.set_max_mds(2)
+        self.wait_until_equal(lambda: len(fs_b.get_active_names()), 2, 30,
+                              reject_fn=lambda v: v > 2 or v < 1)
+
+        # Increase max_mds on fs_a, see a standby take up the role
+        fs_a.set_max_mds(2)
+        self.wait_until_equal(lambda: len(fs_a.get_active_names()), 2, 30,
+                              reject_fn=lambda v: v > 2 or v < 1)
+
+        # Shrink fs_b back to 1, see a daemon go back to standby
+        fs_b.set_max_mds(1)
+        fs_b.deactivate(1)
+        self.wait_until_equal(lambda: len(fs_b.get_active_names()), 1, 30,
+                              reject_fn=lambda v: v > 2 or v < 1)
+
+        # Grow fs_a up to 3, see the former fs_b daemon join it.
+        fs_a.set_max_mds(3)
+        self.wait_until_equal(lambda: len(fs_a.get_active_names()), 3, 60,
+                              reject_fn=lambda v: v > 3 or v < 2)
+
+    def test_standby_for_name(self):
+        # Pick out exactly 4 daemons to be run during test
+        use_daemons = sorted(self.mds_cluster.mds_ids[0:4])
+        mds_a, mds_b, mds_c, mds_d = use_daemons
+        log.info("Using MDS daemons: {0}".format(use_daemons))
+
+        def set_standby_for(leader, follower, replay):
+            self.set_conf("mds.{0}".format(follower), "mds_standby_for_name", leader)
+            if replay:
+                self.set_conf("mds.{0}".format(follower), "mds_standby_replay", "true")
+
+        # Configure two pairs of MDSs that are standby for each other
+        set_standby_for(mds_a, mds_b, True)
+        set_standby_for(mds_b, mds_a, False)
+        set_standby_for(mds_c, mds_d, True)
+        set_standby_for(mds_d, mds_c, False)
+
+        # Create FS alpha and get mds_a to come up as active
+        fs_a = self.mds_cluster.newfs("alpha")
+        self.mds_cluster.mds_restart(mds_a)
+        fs_a.wait_for_daemons()
+        self.assertEqual(fs_a.get_active_names(), [mds_a])
+
+        # Create FS bravo and get mds_c to come up as active
+        fs_b = self.mds_cluster.newfs("bravo")
+        self.mds_cluster.mds_restart(mds_c)
+        fs_b.wait_for_daemons()
+        self.assertEqual(fs_b.get_active_names(), [mds_c])
+
+        # Start the standbys
+        self.mds_cluster.mds_restart(mds_b)
+        self.mds_cluster.mds_restart(mds_d)
+        self.wait_for_daemon_start([mds_b, mds_d])
+
+        def get_info_by_name(fs, mds_name):
+            mds_map = fs.get_mds_map()
+            for gid_str, info in mds_map['info'].items():
+                if info['name'] == mds_name:
+                    return info
+
+            log.warn(json.dumps(mds_map, indent=2))
+            raise RuntimeError("MDS '{0}' not found in filesystem MDSMap".format(mds_name))
+
+        # See both standbys come up as standby replay for the correct ranks
+        # mds_b should be in filesystem alpha following mds_a
+        info_b = get_info_by_name(fs_a, mds_b)
+        self.assertEqual(info_b['state'], "up:standby-replay")
+        self.assertEqual(info_b['standby_for_name'], mds_a)
+        self.assertEqual(info_b['rank'], 0)
+        # mds_d should be in filesystem alpha following mds_c
+        info_d = get_info_by_name(fs_b, mds_d)
+        self.assertEqual(info_d['state'], "up:standby-replay")
+        self.assertEqual(info_d['standby_for_name'], mds_c)
+        self.assertEqual(info_d['rank'], 0)
+
+        # Kill both active daemons
+        self.mds_cluster.mds_stop(mds_a)
+        self.mds_cluster.mds_fail(mds_a)
+        self.mds_cluster.mds_stop(mds_c)
+        self.mds_cluster.mds_fail(mds_c)
+
+        # Wait for standbys to take over
+        fs_a.wait_for_daemons()
+        self.assertEqual(fs_a.get_active_names(), [mds_b])
+        fs_b.wait_for_daemons()
+        self.assertEqual(fs_b.get_active_names(), [mds_d])
+
+        # Start the original active daemons up again
+        self.mds_cluster.mds_restart(mds_a)
+        self.mds_cluster.mds_restart(mds_c)
+        self.wait_for_daemon_start([mds_a, mds_c])
+
+        self.assertEqual(set(self.mds_cluster.get_standby_daemons()),
+                         {mds_a, mds_c})
+
+    def test_standby_for_rank(self):
+        use_daemons = sorted(self.mds_cluster.mds_ids[0:4])
+        mds_a, mds_b, mds_c, mds_d = use_daemons
+        log.info("Using MDS daemons: {0}".format(use_daemons))
+
+        def set_standby_for(leader_rank, leader_fs, follower_id):
+            self.set_conf("mds.{0}".format(follower_id),
+                          "mds_standby_for_rank", leader_rank)
+
+            fscid = leader_fs.get_namespace_id()
+            self.set_conf("mds.{0}".format(follower_id),
+                          "mds_standby_for_fscid", fscid)
+
+        fs_a = self.mds_cluster.newfs("alpha")
+        fs_b = self.mds_cluster.newfs("bravo")
+        set_standby_for(0, fs_a, mds_a)
+        set_standby_for(0, fs_a, mds_b)
+        set_standby_for(0, fs_b, mds_c)
+        set_standby_for(0, fs_b, mds_d)
+
+        self.mds_cluster.mds_restart(mds_a)
+        fs_a.wait_for_daemons()
+        self.assertEqual(fs_a.get_active_names(), [mds_a])
+
+        self.mds_cluster.mds_restart(mds_c)
+        fs_b.wait_for_daemons()
+        self.assertEqual(fs_b.get_active_names(), [mds_c])
+
+        self.mds_cluster.mds_restart(mds_b)
+        self.mds_cluster.mds_restart(mds_d)
+        self.wait_for_daemon_start([mds_b, mds_d])
+
+        self.mds_cluster.mds_stop(mds_a)
+        self.mds_cluster.mds_fail(mds_a)
+        self.mds_cluster.mds_stop(mds_c)
+        self.mds_cluster.mds_fail(mds_c)
+
+        fs_a.wait_for_daemons()
+        self.assertEqual(fs_a.get_active_names(), [mds_b])
+        fs_b.wait_for_daemons()
+        self.assertEqual(fs_b.get_active_names(), [mds_d])
+
+    def test_standby_for_fscid(self):
+        """
+        That I can set a standby FSCID with no rank, and the result is
+        that daemons join any rank for that filesystem.
+        """
+        use_daemons = sorted(self.mds_cluster.mds_ids[0:4])
+        mds_a, mds_b, mds_c, mds_d = use_daemons
+
+        log.info("Using MDS daemons: {0}".format(use_daemons))
+
+        def set_standby_for(leader_fs, follower_id):
+            fscid = leader_fs.get_namespace_id()
+            self.set_conf("mds.{0}".format(follower_id),
+                          "mds_standby_for_fscid", fscid)
+
+        # Create two filesystems which should have two ranks each
+        fs_a = self.mds_cluster.newfs("alpha")
+
+        fs_b = self.mds_cluster.newfs("bravo")
+
+        fs_a.set_max_mds(2)
+        fs_b.set_max_mds(2)
+
+        # Set all the daemons to have a FSCID assignment but no other
+        # standby preferences.
+        set_standby_for(fs_a, mds_a)
+        set_standby_for(fs_a, mds_b)
+        set_standby_for(fs_b, mds_c)
+        set_standby_for(fs_b, mds_d)
+
+        # Now when we start all daemons at once, they should fall into
+        # ranks in the right filesystem
+        self.mds_cluster.mds_restart(mds_a)
+        self.mds_cluster.mds_restart(mds_b)
+        self.mds_cluster.mds_restart(mds_c)
+        self.mds_cluster.mds_restart(mds_d)
+        self.wait_for_daemon_start([mds_a, mds_b, mds_c, mds_d])
+        fs_a.wait_for_daemons()
+        fs_b.wait_for_daemons()
+        self.assertEqual(set(fs_a.get_active_names()), {mds_a, mds_b})
+        self.assertEqual(set(fs_b.get_active_names()), {mds_c, mds_d})
+
+    def test_standby_for_invalid_fscid(self):
+        """
+        That an invalid standby_fscid does not cause a mon crash
+        """
+        use_daemons = sorted(self.mds_cluster.mds_ids[0:3])
+        mds_a, mds_b, mds_c = use_daemons
+        log.info("Using MDS daemons: {0}".format(use_daemons))
+
+        def set_standby_for_rank(leader_rank, follower_id):
+            self.set_conf("mds.{0}".format(follower_id),
+                          "mds_standby_for_rank", leader_rank)
+
+        # Create one fs
+        fs_a = self.mds_cluster.newfs("cephfs")
+
+        # Get configured mons in the cluster, so we can see if any
+        # crashed later.
+        configured_mons = fs_a.mon_manager.get_mon_quorum()
+
+        # Set all the daemons to have a rank assignment but no other
+        # standby preferences.
+        set_standby_for_rank(0, mds_a)
+        set_standby_for_rank(0, mds_b)
+
+        # Set third daemon to have invalid fscid assignment and no other
+        # standby preferences
+        invalid_fscid = 123
+        self.set_conf("mds.{0}".format(mds_c), "mds_standby_for_fscid", invalid_fscid)
+
+        #Restart all the daemons to make the standby preference applied
+        self.mds_cluster.mds_restart(mds_a)
+        self.mds_cluster.mds_restart(mds_b)
+        self.mds_cluster.mds_restart(mds_c)
+        self.wait_for_daemon_start([mds_a, mds_b, mds_c])
+
+        #Stop active mds daemon service of fs
+        if (fs_a.get_active_names(), [mds_a]):
+            self.mds_cluster.mds_stop(mds_a)
+            self.mds_cluster.mds_fail(mds_a)
+            fs_a.wait_for_daemons()
+        else:
+            self.mds_cluster.mds_stop(mds_b)
+            self.mds_cluster.mds_fail(mds_b)
+            fs_a.wait_for_daemons()
+
+        #Get active mons from cluster
+        active_mons = fs_a.mon_manager.get_mon_quorum()
+
+        #Check for active quorum mon status and configured mon status
+        self.assertEqual(active_mons, configured_mons,
+                "Not all mons are in quorum Invalid standby invalid fscid test failed!")
diff --git a/src/ceph/qa/tasks/cephfs/test_flush.py b/src/ceph/qa/tasks/cephfs/test_flush.py
new file mode 100644
index 0000000..1f84e42
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_flush.py
@@ -0,0 +1,113 @@
+
+from textwrap import dedent
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+from tasks.cephfs.filesystem import ObjectNotFound, ROOT_INO
+
+
+class TestFlush(CephFSTestCase):
+    def test_flush(self):
+        self.mount_a.run_shell(["mkdir", "mydir"])
+        self.mount_a.run_shell(["touch", "mydir/alpha"])
+        dir_ino = self.mount_a.path_to_ino("mydir")
+        file_ino = self.mount_a.path_to_ino("mydir/alpha")
+
+        # Unmount the client so that it isn't still holding caps
+        self.mount_a.umount_wait()
+
+        # Before flush, the dirfrag object does not exist
+        with self.assertRaises(ObjectNotFound):
+            self.fs.list_dirfrag(dir_ino)
+
+        # Before flush, the file's backtrace has not been written
+        with self.assertRaises(ObjectNotFound):
+            self.fs.read_backtrace(file_ino)
+
+        # Before flush, there are no dentries in the root
+        self.assertEqual(self.fs.list_dirfrag(ROOT_INO), [])
+
+        # Execute flush
+        flush_data = self.fs.mds_asok(["flush", "journal"])
+        self.assertEqual(flush_data['return_code'], 0)
+
+        # After flush, the dirfrag object has been created
+        dir_list = self.fs.list_dirfrag(dir_ino)
+        self.assertEqual(dir_list, ["alpha_head"])
+
+        # And the 'mydir' dentry is in the root
+        self.assertEqual(self.fs.list_dirfrag(ROOT_INO), ['mydir_head'])
+
+        # ...and the data object has its backtrace
+        backtrace = self.fs.read_backtrace(file_ino)
+        self.assertEqual(['alpha', 'mydir'], [a['dname'] for a in backtrace['ancestors']])
+        self.assertEqual([dir_ino, 1], [a['dirino'] for a in backtrace['ancestors']])
+        self.assertEqual(file_ino, backtrace['ino'])
+
+        # ...and the journal is truncated to just a single subtreemap from the
+        # newly created segment
+        summary_output = self.fs.journal_tool(["event", "get", "summary"])
+        try:
+            self.assertEqual(summary_output,
+                             dedent(
+                                 """
+                                 Events by type:
+                                   SUBTREEMAP: 1
+                                 Errors: 0
+                                 """
+                             ).strip())
+        except AssertionError:
+            # In some states, flushing the journal will leave you
+            # an extra event from locks a client held.   This is
+            # correct behaviour: the MDS is flushing the journal,
+            # it's just that new events are getting added too.
+            # In this case, we should nevertheless see a fully
+            # empty journal after a second flush.
+            self.assertEqual(summary_output,
+                             dedent(
+                                 """
+                                 Events by type:
+                                   SUBTREEMAP: 1
+                                   UPDATE: 1
+                                 Errors: 0
+                                 """
+                             ).strip())
+            flush_data = self.fs.mds_asok(["flush", "journal"])
+            self.assertEqual(flush_data['return_code'], 0)
+            self.assertEqual(self.fs.journal_tool(["event", "get", "summary"]),
+                             dedent(
+                                 """
+                                 Events by type:
+                                   SUBTREEMAP: 1
+                                 Errors: 0
+                                 """
+                             ).strip())
+
+        # Now for deletion!
+        # We will count the RADOS deletions and MDS file purges, to verify that
+        # the expected behaviour is happening as a result of the purge
+        initial_dels = self.fs.mds_asok(['perf', 'dump', 'objecter'])['objecter']['osdop_delete']
+        initial_purges = self.fs.mds_asok(['perf', 'dump', 'mds_cache'])['mds_cache']['strays_enqueued']
+
+        # Use a client to delete a file
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        self.mount_a.run_shell(["rm", "-rf", "mydir"])
+
+        # Flush the journal so that the directory inode can be purged
+        flush_data = self.fs.mds_asok(["flush", "journal"])
+        self.assertEqual(flush_data['return_code'], 0)
+
+        # We expect to see a single file purge
+        self.wait_until_true(
+            lambda: self.fs.mds_asok(['perf', 'dump', 'mds_cache'])['mds_cache']['strays_enqueued'] - initial_purges >= 2,
+            60)
+
+        # We expect two deletions, one of the dirfrag and one of the backtrace
+        self.wait_until_true(
+            lambda: self.fs.mds_asok(['perf', 'dump', 'objecter'])['objecter']['osdop_delete'] - initial_dels >= 2,
+            60)  # timeout is fairly long to allow for tick+rados latencies
+
+        with self.assertRaises(ObjectNotFound):
+            self.fs.list_dirfrag(dir_ino)
+        with self.assertRaises(ObjectNotFound):
+            self.fs.read_backtrace(file_ino)
+        self.assertEqual(self.fs.list_dirfrag(ROOT_INO), [])
diff --git a/src/ceph/qa/tasks/cephfs/test_forward_scrub.py b/src/ceph/qa/tasks/cephfs/test_forward_scrub.py
new file mode 100644
index 0000000..ac912dd
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_forward_scrub.py
@@ -0,0 +1,291 @@
+
+"""
+Test that the forward scrub functionality can traverse metadata and apply
+requested tags, on well formed metadata.
+
+This is *not* the real testing for forward scrub, which will need to test
+how the functionality responds to damaged metadata.
+
+"""
+import json
+
+import logging
+from collections import namedtuple
+from textwrap import dedent
+
+from teuthology.orchestra.run import CommandFailedError
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+
+import struct
+
+log = logging.getLogger(__name__)
+
+
+ValidationError = namedtuple("ValidationError", ["exception", "backtrace"])
+
+
+class TestForwardScrub(CephFSTestCase):
+    MDSS_REQUIRED = 1
+
+    def _read_str_xattr(self, pool, obj, attr):
+        """
+        Read a ceph-encoded string from a rados xattr
+        """
+        output = self.fs.rados(["getxattr", obj, attr], pool=pool)
+        strlen = struct.unpack('i', output[0:4])[0]
+        return output[4:(4 + strlen)]
+
+    def _get_paths_to_ino(self):
+        inos = {}
+        p = self.mount_a.run_shell(["find", "./"])
+        paths = p.stdout.getvalue().strip().split()
+        for path in paths:
+            inos[path] = self.mount_a.path_to_ino(path)
+
+        return inos
+
+    def test_apply_tag(self):
+        self.mount_a.run_shell(["mkdir", "parentdir"])
+        self.mount_a.run_shell(["mkdir", "parentdir/childdir"])
+        self.mount_a.run_shell(["touch", "rfile"])
+        self.mount_a.run_shell(["touch", "parentdir/pfile"])
+        self.mount_a.run_shell(["touch", "parentdir/childdir/cfile"])
+
+        # Build a structure mapping path to inode, as we will later want
+        # to check object by object and objects are named after ino number
+        inos = self._get_paths_to_ino()
+
+        # Flush metadata: this is a friendly test of forward scrub so we're skipping
+        # the part where it's meant to cope with dirty metadata
+        self.mount_a.umount_wait()
+        self.fs.mds_asok(["flush", "journal"])
+
+        tag = "mytag"
+
+        # Execute tagging forward scrub
+        self.fs.mds_asok(["tag", "path", "/parentdir", tag])
+        # Wait for completion
+        import time
+        time.sleep(10)
+        # FIXME watching clog isn't a nice mechanism for this, once we have a ScrubMap we'll
+        # watch that instead
+
+        # Check that dirs were tagged
+        for dirpath in ["./parentdir", "./parentdir/childdir"]:
+            self.assertTagged(inos[dirpath], tag, self.fs.get_metadata_pool_name())
+
+        # Check that files were tagged
+        for filepath in ["./parentdir/pfile", "./parentdir/childdir/cfile"]:
+            self.assertTagged(inos[filepath], tag, self.fs.get_data_pool_name())
+
+        # This guy wasn't in the tag path, shouldn't have been tagged
+        self.assertUntagged(inos["./rfile"])
+
+    def assertUntagged(self, ino):
+        file_obj_name = "{0:x}.00000000".format(ino)
+        with self.assertRaises(CommandFailedError):
+            self._read_str_xattr(
+                self.fs.get_data_pool_name(),
+                file_obj_name,
+                "scrub_tag"
+            )
+
+    def assertTagged(self, ino, tag, pool):
+        file_obj_name = "{0:x}.00000000".format(ino)
+        wrote = self._read_str_xattr(
+            pool,
+            file_obj_name,
+            "scrub_tag"
+        )
+        self.assertEqual(wrote, tag)
+
+    def _validate_linkage(self, expected):
+        inos = self._get_paths_to_ino()
+        try:
+            self.assertDictEqual(inos, expected)
+        except AssertionError:
+            log.error("Expected: {0}".format(json.dumps(expected, indent=2)))
+            log.error("Actual: {0}".format(json.dumps(inos, indent=2)))
+            raise
+
+    def test_orphan_scan(self):
+        # Create some files whose metadata we will flush
+        self.mount_a.run_python(dedent("""
+            import os
+            mount_point = "{mount_point}"
+            parent = os.path.join(mount_point, "parent")
+            os.mkdir(parent)
+            flushed = os.path.join(parent, "flushed")
+            os.mkdir(flushed)
+            for f in ["alpha", "bravo", "charlie"]:
+                open(os.path.join(flushed, f), 'w').write(f)
+        """.format(mount_point=self.mount_a.mountpoint)))
+
+        inos = self._get_paths_to_ino()
+
+        # Flush journal
+        # Umount before flush to avoid cap releases putting
+        # things we don't want in the journal later.
+        self.mount_a.umount_wait()
+        self.fs.mds_asok(["flush", "journal"])
+
+        # Create a new inode that's just in the log, i.e. would
+        # look orphaned to backward scan if backward scan wisnae
+        # respectin' tha scrub_tag xattr.
+        self.mount_a.mount()
+        self.mount_a.run_shell(["mkdir", "parent/unflushed"])
+        self.mount_a.run_shell(["dd", "if=/dev/urandom",
+                                "of=./parent/unflushed/jfile",
+                                "bs=1M", "count=8"])
+        inos["./parent/unflushed"] = self.mount_a.path_to_ino("./parent/unflushed")
+        inos["./parent/unflushed/jfile"] = self.mount_a.path_to_ino("./parent/unflushed/jfile")
+        self.mount_a.umount_wait()
+
+        # Orphan an inode by deleting its dentry
+        # Our victim will be.... bravo.
+        self.mount_a.umount_wait()
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+        self.fs.set_ceph_conf('mds', 'mds verify scatter', False)
+        self.fs.set_ceph_conf('mds', 'mds debug scatterstat', False)
+        frag_obj_id = "{0:x}.00000000".format(inos["./parent/flushed"])
+        self.fs.rados(["rmomapkey", frag_obj_id, "bravo_head"])
+
+        self.fs.mds_restart()
+        self.fs.wait_for_daemons()
+
+        # See that the orphaned file is indeed missing from a client's POV
+        self.mount_a.mount()
+        damaged_state = self._get_paths_to_ino()
+        self.assertNotIn("./parent/flushed/bravo", damaged_state)
+        self.mount_a.umount_wait()
+
+        # Run a tagging forward scrub
+        tag = "mytag123"
+        self.fs.mds_asok(["tag", "path", "/parent", tag])
+
+        # See that the orphan wisnae tagged
+        self.assertUntagged(inos['./parent/flushed/bravo'])
+
+        # See that the flushed-metadata-and-still-present files are tagged
+        self.assertTagged(inos['./parent/flushed/alpha'], tag, self.fs.get_data_pool_name())
+        self.assertTagged(inos['./parent/flushed/charlie'], tag, self.fs.get_data_pool_name())
+
+        # See that journalled-but-not-flushed file *was* tagged
+        self.assertTagged(inos['./parent/unflushed/jfile'], tag, self.fs.get_data_pool_name())
+
+        # Run cephfs-data-scan targeting only orphans
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+        self.fs.data_scan(["scan_extents", self.fs.get_data_pool_name()])
+        self.fs.data_scan([
+            "scan_inodes",
+            "--filter-tag", tag,
+            self.fs.get_data_pool_name()
+        ])
+
+        # After in-place injection stats should be kosher again
+        self.fs.set_ceph_conf('mds', 'mds verify scatter', True)
+        self.fs.set_ceph_conf('mds', 'mds debug scatterstat', True)
+
+        # And we should have all the same linkage we started with,
+        # and no lost+found, and no extra inodes!
+        self.fs.mds_restart()
+        self.fs.wait_for_daemons()
+        self.mount_a.mount()
+        self._validate_linkage(inos)
+
+    def _stash_inotable(self):
+        # Get all active ranks
+        ranks = self.fs.get_all_mds_rank()
+
+        inotable_dict = {}
+        for rank in ranks:
+            inotable_oid = "mds{rank:d}_".format(rank=rank) + "inotable"
+            print "Trying to fetch inotable object: " + inotable_oid
+
+            #self.fs.get_metadata_object("InoTable", "mds0_inotable")
+            inotable_raw = self.fs.get_metadata_object_raw(inotable_oid)
+            inotable_dict[inotable_oid] = inotable_raw
+        return inotable_dict
+
+    def test_inotable_sync(self):
+        self.mount_a.write_n_mb("file1_sixmegs", 6)
+
+        # Flush journal
+        self.mount_a.umount_wait()
+        self.fs.mds_asok(["flush", "journal"])
+
+        inotable_copy = self._stash_inotable()
+
+        self.mount_a.mount()
+
+        self.mount_a.write_n_mb("file2_sixmegs", 6)
+        self.mount_a.write_n_mb("file3_sixmegs", 6)
+
+        inos = self._get_paths_to_ino()
+
+        # Flush journal
+        self.mount_a.umount_wait()
+        self.fs.mds_asok(["flush", "journal"])
+
+        self.mount_a.umount_wait()
+
+        with self.assert_cluster_log("inode table repaired", invert_match=True):
+            self.fs.mds_asok(["scrub_path", "/", "repair", "recursive"])
+
+        self.mds_cluster.mds_stop()
+        self.mds_cluster.mds_fail()
+
+        # Truncate the journal (to ensure the inotable on disk
+        # is all that will be in the InoTable in memory)
+
+        self.fs.journal_tool(["event", "splice",
+            "--inode={0}".format(inos["./file2_sixmegs"]), "summary"])
+
+        self.fs.journal_tool(["event", "splice",
+            "--inode={0}".format(inos["./file3_sixmegs"]), "summary"])
+
+        # Revert to old inotable.
+        for key, value in inotable_copy.iteritems():
+           self.fs.put_metadata_object_raw(key, value)
+
+        self.mds_cluster.mds_restart()
+        self.fs.wait_for_daemons()
+
+        with self.assert_cluster_log("inode table repaired"):
+            self.fs.mds_asok(["scrub_path", "/", "repair", "recursive"])
+
+        self.mds_cluster.mds_stop()
+        table_text = self.fs.table_tool(["0", "show", "inode"])
+        table = json.loads(table_text)
+        self.assertGreater(
+                table['0']['data']['inotable']['free'][0]['start'],
+                inos['./file3_sixmegs'])
+
+    def test_backtrace_repair(self):
+        """
+        That the MDS can repair an inodes backtrace in the data pool
+        if it is found to be damaged.
+        """
+        # Create a file for subsequent checks
+        self.mount_a.run_shell(["mkdir", "parent_a"])
+        self.mount_a.run_shell(["touch", "parent_a/alpha"])
+        file_ino = self.mount_a.path_to_ino("parent_a/alpha")
+
+        # That backtrace and layout are written after initial flush
+        self.fs.mds_asok(["flush", "journal"])
+        backtrace = self.fs.read_backtrace(file_ino)
+        self.assertEqual(['alpha', 'parent_a'],
+                         [a['dname'] for a in backtrace['ancestors']])
+
+        # Go corrupt the backtrace
+        self.fs._write_data_xattr(file_ino, "parent",
+                                  "oh i'm sorry did i overwrite your xattr?")
+
+        with self.assert_cluster_log("bad backtrace on inode"):
+            self.fs.mds_asok(["scrub_path", "/", "repair", "recursive"])
+        self.fs.mds_asok(["flush", "journal"])
+        backtrace = self.fs.read_backtrace(file_ino)
+        self.assertEqual(['alpha', 'parent_a'],
+                         [a['dname'] for a in backtrace['ancestors']])
diff --git a/src/ceph/qa/tasks/cephfs/test_fragment.py b/src/ceph/qa/tasks/cephfs/test_fragment.py
new file mode 100644
index 0000000..a62ef74
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_fragment.py
@@ -0,0 +1,232 @@
+
+
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+from teuthology.orchestra import run
+
+import logging
+log = logging.getLogger(__name__)
+
+
+class TestFragmentation(CephFSTestCase):
+    CLIENTS_REQUIRED = 1
+    MDSS_REQUIRED = 1
+
+    def get_splits(self):
+        return self.fs.mds_asok(['perf', 'dump', 'mds'])['mds']['dir_split']
+
+    def get_merges(self):
+        return self.fs.mds_asok(['perf', 'dump', 'mds'])['mds']['dir_merge']
+
+    def get_dir_ino(self, path):
+        dir_cache = self.fs.read_cache(path, 0)
+        dir_ino = None
+        dir_inono = self.mount_a.path_to_ino(path.strip("/"))
+        for ino in dir_cache:
+            if ino['ino'] == dir_inono:
+                dir_ino = ino
+                break
+        self.assertIsNotNone(dir_ino)
+        return dir_ino
+
+    def _configure(self, **kwargs):
+        """
+        Apply kwargs as MDS configuration settings, enable dirfrags
+        and restart the MDSs.
+        """
+        kwargs['mds_bal_frag'] = "true"
+
+        for k, v in kwargs.items():
+            self.ceph_cluster.set_ceph_conf("mds", k, v.__str__())
+
+        self.fs.set_allow_dirfrags(True)
+
+        self.mds_cluster.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+    def test_oversize(self):
+        """
+        That a directory is split when it becomes too large.
+        """
+
+        split_size = 20
+        merge_size = 5
+
+        self._configure(
+            mds_bal_split_size=split_size,
+            mds_bal_merge_size=merge_size,
+            mds_bal_split_bits=1
+        )
+
+        self.assertEqual(self.get_splits(), 0)
+
+        self.mount_a.create_n_files("splitdir/file", split_size + 1)
+
+        self.wait_until_true(
+            lambda: self.get_splits() == 1,
+            timeout=30
+        )
+
+        frags = self.get_dir_ino("/splitdir")['dirfrags']
+        self.assertEqual(len(frags), 2)
+        self.assertEqual(frags[0]['dirfrag'], "0x10000000000.0*")
+        self.assertEqual(frags[1]['dirfrag'], "0x10000000000.1*")
+        self.assertEqual(
+            sum([len(f['dentries']) for f in frags]),
+            split_size + 1
+        )
+
+        self.assertEqual(self.get_merges(), 0)
+
+        self.mount_a.run_shell(["rm", "-f", run.Raw("splitdir/file*")])
+
+        self.wait_until_true(
+            lambda: self.get_merges() == 1,
+            timeout=30
+        )
+
+        self.assertEqual(len(self.get_dir_ino("/splitdir")["dirfrags"]), 1)
+
+    def test_rapid_creation(self):
+        """
+        That the fast-splitting limit of 1.5x normal limit is
+        applied when creating dentries quickly.
+        """
+
+        split_size = 100
+        merge_size = 1
+
+        self._configure(
+            mds_bal_split_size=split_size,
+            mds_bal_merge_size=merge_size,
+            mds_bal_split_bits=3,
+            mds_bal_fragment_size_max=int(split_size * 1.5 + 2)
+        )
+
+        # We test this only at a single split level.  If a client was sending
+        # IO so fast that it hit a second split before the first split
+        # was complete, it could violate mds_bal_fragment_size_max -- there
+        # is a window where the child dirfrags of a split are unfrozen
+        # (so they can grow), but still have STATE_FRAGMENTING (so they
+        # can't be split).
+
+        # By writing 4x the split size when the split bits are set
+        # to 3 (i.e. 4-ways), I am reasonably sure to see precisely
+        # one split.  The test is to check whether that split
+        # happens soon enough that the client doesn't exceed
+        # 2x the split_size (the "immediate" split mode should
+        # kick in at 1.5x the split size).
+
+        self.assertEqual(self.get_splits(), 0)
+        self.mount_a.create_n_files("splitdir/file", split_size * 4)
+        self.wait_until_equal(
+            self.get_splits,
+            1,
+            reject_fn=lambda s: s > 1,
+            timeout=30
+        )
+
+    def test_deep_split(self):
+        """
+        That when the directory grows many times larger than split size,
+        the fragments get split again.
+        """
+
+        split_size = 100
+        merge_size = 1  # i.e. don't merge frag unless its empty
+        split_bits = 1
+
+        branch_factor = 2**split_bits
+
+        # Arbitrary: how many levels shall we try fragmenting before
+        # ending the test?
+        max_depth = 5
+
+        self._configure(
+            mds_bal_split_size=split_size,
+            mds_bal_merge_size=merge_size,
+            mds_bal_split_bits=split_bits
+        )
+
+        # Each iteration we will create another level of fragments.  The
+        # placement of dentries into fragments is by hashes (i.e. pseudo
+        # random), so we rely on statistics to get the behaviour that
+        # by writing about 1.5x as many dentries as the split_size times
+        # the number of frags, we will get them all to exceed their
+        # split size and trigger a split.
+        depth = 0
+        files_written = 0
+        splits_expected = 0
+        while depth < max_depth:
+            log.info("Writing files for depth {0}".format(depth))
+            target_files = branch_factor**depth * int(split_size * 1.5)
+            create_files = target_files - files_written
+
+            self.ceph_cluster.mon_manager.raw_cluster_cmd("log",
+                "{0} Writing {1} files (depth={2})".format(
+                    self.__class__.__name__, create_files, depth
+                ))
+            self.mount_a.create_n_files("splitdir/file_{0}".format(depth),
+                                        create_files)
+            self.ceph_cluster.mon_manager.raw_cluster_cmd("log",
+                "{0} Done".format(self.__class__.__name__))
+
+            files_written += create_files
+            log.info("Now have {0} files".format(files_written))
+
+            splits_expected += branch_factor**depth
+            log.info("Waiting to see {0} splits".format(splits_expected))
+            try:
+                self.wait_until_equal(
+                    self.get_splits,
+                    splits_expected,
+                    timeout=30,
+                    reject_fn=lambda x: x > splits_expected
+                )
+
+                frags = self.get_dir_ino("/splitdir")['dirfrags']
+                self.assertEqual(len(frags), branch_factor**(depth+1))
+                self.assertEqual(
+                    sum([len(f['dentries']) for f in frags]),
+                    target_files
+                )
+            except:
+                # On failures, log what fragmentation we actually ended
+                # up with.  This block is just for logging, at the end
+                # we raise the exception again.
+                frags = self.get_dir_ino("/splitdir")['dirfrags']
+                log.info("depth={0} splits_expected={1} files_written={2}".format(
+                    depth, splits_expected, files_written
+                ))
+                log.info("Dirfrags:")
+                for f in frags:
+                    log.info("{0}: {1}".format(
+                        f['dirfrag'], len(f['dentries'])
+                    ))
+                raise
+
+            depth += 1
+
+        # Remember the inode number because we will be checking for
+        # objects later.
+        dir_inode_no = self.mount_a.path_to_ino("splitdir")
+
+        self.mount_a.run_shell(["rm", "-rf", "splitdir/"])
+        self.mount_a.umount_wait()
+
+        self.fs.mds_asok(['flush', 'journal'])
+
+        # Wait for all strays to purge
+        self.wait_until_equal(
+            lambda: self.fs.mds_asok(['perf', 'dump', 'mds_cache']
+                                     )['mds_cache']['num_strays'],
+            0,
+            timeout=1200
+        )
+        # Check that the metadata pool objects for all the myriad
+        # child fragments are gone
+        metadata_objs = self.fs.rados(["ls"])
+        frag_objs = []
+        for o in metadata_objs:
+            if o.startswith("{0:x}.".format(dir_inode_no)):
+                frag_objs.append(o)
+        self.assertListEqual(frag_objs, [])
diff --git a/src/ceph/qa/tasks/cephfs/test_full.py b/src/ceph/qa/tasks/cephfs/test_full.py
new file mode 100644
index 0000000..e69ccb3
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_full.py
@@ -0,0 +1,414 @@
+
+
+import json
+import logging
+import os
+from textwrap import dedent
+import time
+from teuthology.orchestra.run import CommandFailedError
+from tasks.cephfs.fuse_mount import FuseMount
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+
+
+log = logging.getLogger(__name__)
+
+
+class FullnessTestCase(CephFSTestCase):
+    CLIENTS_REQUIRED = 2
+
+    # Subclasses define whether they're filling whole cluster or just data pool
+    data_only = False
+
+    # Subclasses define how many bytes should be written to achieve fullness
+    pool_capacity = None
+    fill_mb = None
+
+    # Subclasses define what fullness means to them
+    def is_full(self):
+        raise NotImplementedError()
+
+    def setUp(self):
+        CephFSTestCase.setUp(self)
+
+        # These tests just use a single active MDS throughout, so remember its ID
+        # for use in mds_asok calls
+        self.active_mds_id = self.fs.get_active_names()[0]
+
+        # Capture the initial OSD map epoch for later use
+        self.initial_osd_epoch = json.loads(
+            self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json").strip()
+        )['epoch']
+
+        # Check the initial barrier epoch on the MDS: this should be
+        # set to the latest map at MDS startup.  We do this check in
+        # setUp to get in there before subclasses might touch things
+        # in their own setUp functions.
+        self.assertGreaterEqual(self.fs.mds_asok(["status"], mds_id=self.active_mds_id)['osdmap_epoch_barrier'],
+                                self.initial_osd_epoch)
+
+    def test_barrier(self):
+        """
+        That when an OSD epoch barrier is set on an MDS, subsequently
+        issued capabilities cause clients to update their OSD map to that
+        epoch.
+        """
+
+        # Sync up clients with initial MDS OSD map barrier
+        self.mount_a.open_no_data("foo")
+        self.mount_b.open_no_data("bar")
+
+        # Grab mounts' initial OSD epochs: later we will check that
+        # it hasn't advanced beyond this point.
+        mount_a_initial_epoch = self.mount_a.get_osd_epoch()[0]
+        mount_b_initial_epoch = self.mount_b.get_osd_epoch()[0]
+
+        # Freshly mounted at start of test, should be up to date with OSD map
+        self.assertGreaterEqual(mount_a_initial_epoch, self.initial_osd_epoch)
+        self.assertGreaterEqual(mount_b_initial_epoch, self.initial_osd_epoch)
+
+        # Set and unset a flag to cause OSD epoch to increment
+        self.fs.mon_manager.raw_cluster_cmd("osd", "set", "pause")
+        self.fs.mon_manager.raw_cluster_cmd("osd", "unset", "pause")
+
+        out = self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json").strip()
+        new_epoch = json.loads(out)['epoch']
+        self.assertNotEqual(self.initial_osd_epoch, new_epoch)
+
+        # Do a metadata operation on clients, witness that they end up with
+        # the old OSD map from startup time (nothing has prompted client
+        # to update its map)
+        self.mount_a.open_no_data("alpha")
+        self.mount_b.open_no_data("bravo1")
+
+        # Sleep long enough that if the OSD map was propagating it would
+        # have done so (this is arbitrary because we are 'waiting' for something
+        # to *not* happen).
+        time.sleep(30)
+
+        mount_a_epoch, mount_a_barrier = self.mount_a.get_osd_epoch()
+        self.assertEqual(mount_a_epoch, mount_a_initial_epoch)
+        mount_b_epoch, mount_b_barrier = self.mount_b.get_osd_epoch()
+        self.assertEqual(mount_b_epoch, mount_b_initial_epoch)
+
+        # Set a barrier on the MDS
+        self.fs.mds_asok(["osdmap", "barrier", new_epoch.__str__()], mds_id=self.active_mds_id)
+
+        # Do an operation on client B, witness that it ends up with
+        # the latest OSD map from the barrier.  This shouldn't generate any
+        # cap revokes to A because B was already the last one to touch
+        # a file in root.
+        self.mount_b.run_shell(["touch", "bravo2"])
+        self.mount_b.open_no_data("bravo2")
+
+        # Some time passes here because the metadata part of the operation
+        # completes immediately, while the resulting OSD map update happens
+        # asynchronously (it's an Objecter::_maybe_request_map) as a result
+        # of seeing the new epoch barrier.
+        self.wait_until_equal(
+            lambda: self.mount_b.get_osd_epoch(),
+            (new_epoch, new_epoch),
+            30,
+            lambda x: x[0] > new_epoch or x[1] > new_epoch)
+
+        # ...and none of this should have affected the oblivious mount a,
+        # because it wasn't doing any data or metadata IO
+        mount_a_epoch, mount_a_barrier = self.mount_a.get_osd_epoch()
+        self.assertEqual(mount_a_epoch, mount_a_initial_epoch)
+
+    def _data_pool_name(self):
+        data_pool_names = self.fs.get_data_pool_names()
+        if len(data_pool_names) > 1:
+            raise RuntimeError("This test can't handle multiple data pools")
+        else:
+            return data_pool_names[0]
+
+    def _test_full(self, easy_case):
+        """
+        - That a client trying to write data to a file is prevented
+        from doing so with an -EFULL result
+        - That they are also prevented from creating new files by the MDS.
+        - That they may delete another file to get the system healthy again
+
+        :param easy_case: if true, delete a successfully written file to
+                          free up space.  else, delete the file that experienced
+                          the failed write.
+        """
+
+        osd_mon_report_interval_max = int(self.fs.get_config("osd_mon_report_interval_max", service_type='osd'))
+
+        log.info("Writing {0}MB should fill this cluster".format(self.fill_mb))
+
+        # Fill up the cluster.  This dd may or may not fail, as it depends on
+        # how soon the cluster recognises its own fullness
+        self.mount_a.write_n_mb("large_file_a", self.fill_mb / 2)
+        try:
+            self.mount_a.write_n_mb("large_file_b", self.fill_mb / 2)
+        except CommandFailedError:
+            log.info("Writing file B failed (full status happened already)")
+            assert self.is_full()
+        else:
+            log.info("Writing file B succeeded (full status will happen soon)")
+            self.wait_until_true(lambda: self.is_full(),
+                                 timeout=osd_mon_report_interval_max * 5)
+
+        # Attempting to write more data should give me ENOSPC
+        with self.assertRaises(CommandFailedError) as ar:
+            self.mount_a.write_n_mb("large_file_b", 50, seek=self.fill_mb / 2)
+        self.assertEqual(ar.exception.exitstatus, 1)  # dd returns 1 on "No space"
+
+        # Wait for the MDS to see the latest OSD map so that it will reliably
+        # be applying the policy of rejecting non-deletion metadata operations
+        # while in the full state.
+        osd_epoch = json.loads(self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json-pretty"))['epoch']
+        self.wait_until_true(
+            lambda: self.fs.mds_asok(['status'], mds_id=self.active_mds_id)['osdmap_epoch'] >= osd_epoch,
+            timeout=10)
+
+        if not self.data_only:
+            with self.assertRaises(CommandFailedError):
+                self.mount_a.write_n_mb("small_file_1", 0)
+
+        # Clear out some space
+        if easy_case:
+            self.mount_a.run_shell(['rm', '-f', 'large_file_a'])
+            self.mount_a.run_shell(['rm', '-f', 'large_file_b'])
+        else:
+            # In the hard case it is the file that filled the system.
+            # Before the new #7317 (ENOSPC, epoch barrier) changes, this
+            # would fail because the last objects written would be
+            # stuck in the client cache as objecter operations.
+            self.mount_a.run_shell(['rm', '-f', 'large_file_b'])
+            self.mount_a.run_shell(['rm', '-f', 'large_file_a'])
+
+        # Here we are waiting for two things to happen:
+        # * The MDS to purge the stray folder and execute object deletions
+        #  * The OSDs to inform the mon that they are no longer full
+        self.wait_until_true(lambda: not self.is_full(),
+                             timeout=osd_mon_report_interval_max * 5)
+
+        # Wait for the MDS to see the latest OSD map so that it will reliably
+        # be applying the free space policy
+        osd_epoch = json.loads(self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json-pretty"))['epoch']
+        self.wait_until_true(
+            lambda: self.fs.mds_asok(['status'], mds_id=self.active_mds_id)['osdmap_epoch'] >= osd_epoch,
+            timeout=10)
+
+        # Now I should be able to write again
+        self.mount_a.write_n_mb("large_file", 50, seek=0)
+
+        # Ensure that the MDS keeps its OSD epoch barrier across a restart
+
+    def test_full_different_file(self):
+        self._test_full(True)
+
+    def test_full_same_file(self):
+        self._test_full(False)
+
+    def _remote_write_test(self, template):
+        """
+        Run some remote python in a way that's useful for
+        testing free space behaviour (see test_* methods using this)
+        """
+        file_path = os.path.join(self.mount_a.mountpoint, "full_test_file")
+
+        # Enough to trip the full flag
+        osd_mon_report_interval_max = int(self.fs.get_config("osd_mon_report_interval_max", service_type='osd'))
+        mon_tick_interval = int(self.fs.get_config("mon_tick_interval", service_type="mon"))
+
+        # Sufficient data to cause RADOS cluster to go 'full'
+        log.info("pool capacity {0}, {1}MB should be enough to fill it".format(self.pool_capacity, self.fill_mb))
+
+        # Long enough for RADOS cluster to notice it is full and set flag on mons
+        # (report_interval for mon to learn PG stats, tick interval for it to update OSD map,
+        #  factor of 1.5 for I/O + network latency in committing OSD map and distributing it
+        #  to the OSDs)
+        full_wait = (osd_mon_report_interval_max + mon_tick_interval) * 1.5
+
+        # Configs for this test should bring this setting down in order to
+        # run reasonably quickly
+        if osd_mon_report_interval_max > 10:
+            log.warn("This test may run rather slowly unless you decrease"
+                     "osd_mon_report_interval_max (5 is a good setting)!")
+
+        self.mount_a.run_python(template.format(
+            fill_mb=self.fill_mb,
+            file_path=file_path,
+            full_wait=full_wait,
+            is_fuse=isinstance(self.mount_a, FuseMount)
+        ))
+
+    def test_full_fclose(self):
+        # A remote script which opens a file handle, fills up the filesystem, and then
+        # checks that ENOSPC errors on buffered writes appear correctly as errors in fsync
+        remote_script = dedent("""
+            import time
+            import datetime
+            import subprocess
+            import os
+
+            # Write some buffered data through before going full, all should be well
+            print "writing some data through which we expect to succeed"
+            bytes = 0
+            f = os.open("{file_path}", os.O_WRONLY | os.O_CREAT)
+            bytes += os.write(f, 'a' * 4096)
+            os.fsync(f)
+            print "fsync'ed data successfully, will now attempt to fill fs"
+
+            # Okay, now we're going to fill up the filesystem, and then keep
+            # writing until we see an error from fsync.  As long as we're doing
+            # buffered IO, the error should always only appear from fsync and not
+            # from write
+            full = False
+
+            for n in range(0, {fill_mb}):
+                bytes += os.write(f, 'x' * 1024 * 1024)
+                print "wrote bytes via buffered write, may repeat"
+            print "done writing bytes"
+
+            # OK, now we should sneak in under the full condition
+            # due to the time it takes the OSDs to report to the
+            # mons, and get a successful fsync on our full-making data
+            os.fsync(f)
+            print "successfully fsync'ed prior to getting full state reported"
+
+            # Now wait for the full flag to get set so that our
+            # next flush IO will fail
+            time.sleep(30)
+
+            # A buffered IO, should succeed
+            print "starting buffered write we expect to succeed"
+            os.write(f, 'x' * 4096)
+            print "wrote, now waiting 30s and then doing a close we expect to fail"
+
+            # Wait long enough for a background flush that should fail
+            time.sleep(30)
+
+            if {is_fuse}:
+                # ...and check that the failed background flush is reflected in fclose
+                try:
+                    os.close(f)
+                except OSError:
+                    print "close() returned an error as expected"
+                else:
+                    raise RuntimeError("close() failed to raise error")
+            else:
+                # The kernel cephfs client does not raise errors on fclose
+                os.close(f)
+
+            os.unlink("{file_path}")
+            """)
+        self._remote_write_test(remote_script)
+
+    def test_full_fsync(self):
+        """
+        That when the full flag is encountered during asynchronous
+        flushes, such that an fwrite() succeeds but an fsync/fclose()
+        should return the ENOSPC error.
+        """
+
+        # A remote script which opens a file handle, fills up the filesystem, and then
+        # checks that ENOSPC errors on buffered writes appear correctly as errors in fsync
+        remote_script = dedent("""
+            import time
+            import datetime
+            import subprocess
+            import os
+
+            # Write some buffered data through before going full, all should be well
+            print "writing some data through which we expect to succeed"
+            bytes = 0
+            f = os.open("{file_path}", os.O_WRONLY | os.O_CREAT)
+            bytes += os.write(f, 'a' * 4096)
+            os.fsync(f)
+            print "fsync'ed data successfully, will now attempt to fill fs"
+
+            # Okay, now we're going to fill up the filesystem, and then keep
+            # writing until we see an error from fsync.  As long as we're doing
+            # buffered IO, the error should always only appear from fsync and not
+            # from write
+            full = False
+
+            for n in range(0, {fill_mb} + 1):
+                try:
+                    bytes += os.write(f, 'x' * 1024 * 1024)
+                    print "wrote bytes via buffered write, moving on to fsync"
+                except OSError as e:
+                    print "Unexpected error %s from write() instead of fsync()" % e
+                    raise
+
+                try:
+                    os.fsync(f)
+                    print "fsync'ed successfully"
+                except OSError as e:
+                    print "Reached fullness after %.2f MB" % (bytes / (1024.0 * 1024.0))
+                    full = True
+                    break
+                else:
+                    print "Not full yet after %.2f MB" % (bytes / (1024.0 * 1024.0))
+
+                if n > {fill_mb} * 0.8:
+                    # Be cautious in the last region where we expect to hit
+                    # the full condition, so that we don't overshoot too dramatically
+                    print "sleeping a bit as we've exceeded 80% of our expected full ratio"
+                    time.sleep({full_wait})
+
+            if not full:
+                raise RuntimeError("Failed to reach fullness after writing %d bytes" % bytes)
+
+            # close() should not raise an error because we already caught it in
+            # fsync.  There shouldn't have been any more writeback errors
+            # since then because all IOs got cancelled on the full flag.
+            print "calling close"
+            os.close(f)
+            print "close() did not raise error"
+
+            os.unlink("{file_path}")
+            """)
+
+        self._remote_write_test(remote_script)
+
+
+class TestQuotaFull(FullnessTestCase):
+    """
+    Test per-pool fullness, which indicates quota limits exceeded
+    """
+    pool_capacity = 1024 * 1024 * 32   # arbitrary low-ish limit
+    fill_mb = pool_capacity / (1024 * 1024)
+
+    # We are only testing quota handling on the data pool, not the metadata
+    # pool.
+    data_only = True
+
+    def setUp(self):
+        super(TestQuotaFull, self).setUp()
+
+        pool_name = self.fs.get_data_pool_name()
+        self.fs.mon_manager.raw_cluster_cmd("osd", "pool", "set-quota", pool_name,
+                                            "max_bytes", "{0}".format(self.pool_capacity))
+
+    def is_full(self):
+        return self.fs.is_pool_full(self.fs.get_data_pool_name())
+
+
+class TestClusterFull(FullnessTestCase):
+    """
+    Test cluster-wide fullness, which indicates that an OSD has become too full
+    """
+    pool_capacity = None
+    REQUIRE_MEMSTORE = True
+
+    def setUp(self):
+        super(TestClusterFull, self).setUp()
+
+        if self.pool_capacity is None:
+            # This is a hack to overcome weird fluctuations in the reported
+            # `max_avail` attribute of pools that sometimes occurs in between
+            # tests (reason as yet unclear, but this dodges the issue)
+            TestClusterFull.pool_capacity = self.fs.get_pool_df(self._data_pool_name())['max_avail']
+            TestClusterFull.fill_mb = int(1.05 * (self.pool_capacity / (1024.0 * 1024.0)))
+
+    def is_full(self):
+        return self.fs.is_full()
+
+# Hide the parent class so that unittest.loader doesn't try to run it.
+del globals()['FullnessTestCase']
diff --git a/src/ceph/qa/tasks/cephfs/test_journal_migration.py b/src/ceph/qa/tasks/cephfs/test_journal_migration.py
new file mode 100644
index 0000000..64fe939
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_journal_migration.py
@@ -0,0 +1,118 @@
+
+from StringIO import StringIO
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+from tasks.workunit import task as workunit
+
+JOURNAL_FORMAT_LEGACY = 0
+JOURNAL_FORMAT_RESILIENT = 1
+
+
+class TestJournalMigration(CephFSTestCase):
+    CLIENTS_REQUIRED = 1
+    MDSS_REQUIRED = 2
+
+    def test_journal_migration(self):
+        old_journal_version = JOURNAL_FORMAT_LEGACY
+        new_journal_version = JOURNAL_FORMAT_RESILIENT
+
+        # Pick out two daemons to use
+        mds_a, mds_b = sorted(self.mds_cluster.mds_ids[0:2]) 
+
+        self.mount_a.umount_wait()
+        self.fs.mds_stop()
+
+        # Enable standby replay, to cover the bug case #8811 where
+        # a standby replay might mistakenly end up trying to rewrite
+        # the journal at the same time as an active daemon.
+        self.fs.set_ceph_conf('mds', 'mds standby replay', "true")
+        self.fs.set_ceph_conf('mds', 'mds standby for rank', "0")
+
+        # Create a filesystem using the older journal format.
+        self.fs.set_ceph_conf('mds', 'mds journal format', old_journal_version)
+        self.fs.recreate()
+        self.fs.mds_restart(mds_id=mds_a)
+        self.fs.wait_for_daemons()
+        self.assertEqual(self.fs.get_active_names(), [mds_a])
+
+        def replay_names():
+            return [s['name']
+                    for s in self.fs.status().get_replays(fscid = self.fs.id)]
+
+        # Start the standby and wait for it to come up
+        self.fs.mds_restart(mds_id=mds_b)
+        self.wait_until_equal(
+                replay_names,
+                [mds_b],
+                timeout = 30)
+
+        # Do some client work so that the log is populated with something.
+        with self.mount_a.mounted():
+            self.mount_a.create_files()
+            self.mount_a.check_files()  # sanity, this should always pass
+
+            # Run a more substantial workunit so that the length of the log to be
+            # coverted is going span at least a few segments
+            workunit(self.ctx, {
+                'clients': {
+                    "client.{0}".format(self.mount_a.client_id): ["suites/fsstress.sh"],
+                },
+                "timeout": "3h"
+            })
+
+        # Modify the ceph.conf to ask the MDS to use the new journal format.
+        self.fs.set_ceph_conf('mds', 'mds journal format', new_journal_version)
+
+        # Restart the MDS.
+        self.fs.mds_fail_restart(mds_id=mds_a)
+        self.fs.mds_fail_restart(mds_id=mds_b)
+
+        # This ensures that all daemons come up into a valid state
+        self.fs.wait_for_daemons()
+
+        # Check that files created in the initial client workload are still visible
+        # in a client mount.
+        with self.mount_a.mounted():
+            self.mount_a.check_files()
+
+        # Verify that the journal really has been rewritten.
+        journal_version = self.fs.get_journal_version()
+        if journal_version != new_journal_version:
+            raise RuntimeError("Journal was not upgraded, version should be {0} but is {1}".format(
+                new_journal_version, journal_version()
+            ))
+
+        # Verify that cephfs-journal-tool can now read the rewritten journal
+        inspect_out = self.fs.journal_tool(["journal", "inspect"])
+        if not inspect_out.endswith(": OK"):
+            raise RuntimeError("Unexpected journal-tool result: '{0}'".format(
+                inspect_out
+            ))
+
+        self.fs.journal_tool(["event", "get", "json", "--path", "/tmp/journal.json"])
+        p = self.fs.tool_remote.run(
+            args=[
+                "python",
+                "-c",
+                "import json; print len(json.load(open('/tmp/journal.json')))"
+            ],
+            stdout=StringIO())
+        event_count = int(p.stdout.getvalue().strip())
+        if event_count < 1000:
+            # Approximate value of "lots", expected from having run fsstress
+            raise RuntimeError("Unexpectedly few journal events: {0}".format(event_count))
+
+        # Do some client work to check that writing the log is still working
+        with self.mount_a.mounted():
+            workunit(self.ctx, {
+                'clients': {
+                    "client.{0}".format(self.mount_a.client_id): ["fs/misc/trivial_sync.sh"],
+                },
+                "timeout": "3h"
+            })
+
+        # Check that both an active and a standby replay are still up
+        self.assertEqual(len(replay_names()), 1)
+        self.assertEqual(len(self.fs.get_active_names()), 1)
+        self.assertTrue(self.mds_cluster.mds_daemons[mds_a].running())
+        self.assertTrue(self.mds_cluster.mds_daemons[mds_b].running())
+
diff --git a/src/ceph/qa/tasks/cephfs/test_journal_repair.py b/src/ceph/qa/tasks/cephfs/test_journal_repair.py
new file mode 100644
index 0000000..62cbbb0
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_journal_repair.py
@@ -0,0 +1,443 @@
+
+"""
+Test our tools for recovering the content of damaged journals
+"""
+
+import json
+import logging
+from textwrap import dedent
+import time
+
+from teuthology.exceptions import CommandFailedError, ConnectionLostError
+from tasks.cephfs.filesystem import ObjectNotFound, ROOT_INO
+from tasks.cephfs.cephfs_test_case import CephFSTestCase, for_teuthology
+from tasks.workunit import task as workunit
+
+log = logging.getLogger(__name__)
+
+
+class TestJournalRepair(CephFSTestCase):
+    MDSS_REQUIRED = 2
+
+    def test_inject_to_empty(self):
+        """
+        That when some dentries in the journal but nothing is in
+        the backing store, we correctly populate the backing store
+        from the journalled dentries.
+        """
+
+        # Inject metadata operations
+        self.mount_a.run_shell(["touch", "rootfile"])
+        self.mount_a.run_shell(["mkdir", "subdir"])
+        self.mount_a.run_shell(["touch", "subdir/subdirfile"])
+        # There are several different paths for handling hardlinks, depending
+        # on whether an existing dentry (being overwritten) is also a hardlink
+        self.mount_a.run_shell(["mkdir", "linkdir"])
+
+        # Test inode -> remote transition for a dentry
+        self.mount_a.run_shell(["touch", "linkdir/link0"])
+        self.mount_a.run_shell(["rm", "-f", "linkdir/link0"])
+        self.mount_a.run_shell(["ln", "subdir/subdirfile", "linkdir/link0"])
+
+        # Test nothing -> remote transition
+        self.mount_a.run_shell(["ln", "subdir/subdirfile", "linkdir/link1"])
+
+        # Test remote -> inode transition
+        self.mount_a.run_shell(["ln", "subdir/subdirfile", "linkdir/link2"])
+        self.mount_a.run_shell(["rm", "-f", "linkdir/link2"])
+        self.mount_a.run_shell(["touch", "linkdir/link2"])
+
+        # Test remote -> diff remote transition
+        self.mount_a.run_shell(["ln", "subdir/subdirfile", "linkdir/link3"])
+        self.mount_a.run_shell(["rm", "-f", "linkdir/link3"])
+        self.mount_a.run_shell(["ln", "rootfile", "linkdir/link3"])
+
+        # Test an empty directory
+        self.mount_a.run_shell(["mkdir", "subdir/subsubdir"])
+        self.mount_a.run_shell(["sync"])
+
+        # Before we unmount, make a note of the inode numbers, later we will
+        # check that they match what we recover from the journal
+        rootfile_ino = self.mount_a.path_to_ino("rootfile")
+        subdir_ino = self.mount_a.path_to_ino("subdir")
+        linkdir_ino = self.mount_a.path_to_ino("linkdir")
+        subdirfile_ino = self.mount_a.path_to_ino("subdir/subdirfile")
+        subsubdir_ino = self.mount_a.path_to_ino("subdir/subsubdir")
+
+        self.mount_a.umount_wait()
+
+        # Stop the MDS
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        # Now, the journal should contain the operations, but the backing
+        # store shouldn't
+        with self.assertRaises(ObjectNotFound):
+            self.fs.list_dirfrag(subdir_ino)
+        self.assertEqual(self.fs.list_dirfrag(ROOT_INO), [])
+
+        # Execute the dentry recovery, this should populate the backing store
+        self.fs.journal_tool(['event', 'recover_dentries', 'list'])
+
+        # Dentries in ROOT_INO are present
+        self.assertEqual(sorted(self.fs.list_dirfrag(ROOT_INO)), sorted(['rootfile_head', 'subdir_head', 'linkdir_head']))
+        self.assertEqual(self.fs.list_dirfrag(subdir_ino), ['subdirfile_head', 'subsubdir_head'])
+        self.assertEqual(sorted(self.fs.list_dirfrag(linkdir_ino)),
+                         sorted(['link0_head', 'link1_head', 'link2_head', 'link3_head']))
+
+        # Now check the MDS can read what we wrote: truncate the journal
+        # and start the mds.
+        self.fs.journal_tool(['journal', 'reset'])
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        # List files
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        # First ls -R to populate MDCache, such that hardlinks will
+        # resolve properly (recover_dentries does not create backtraces,
+        # so ordinarily hardlinks to inodes that happen not to have backtraces
+        # will be invisible in readdir).
+        # FIXME: hook in forward scrub here to regenerate backtraces
+        proc = self.mount_a.run_shell(['ls', '-R'])
+        self.mount_a.umount_wait()  # remount to clear client cache before our second ls
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        proc = self.mount_a.run_shell(['ls', '-R'])
+        self.assertEqual(proc.stdout.getvalue().strip(),
+                         dedent("""
+                         .:
+                         linkdir
+                         rootfile
+                         subdir
+
+                         ./linkdir:
+                         link0
+                         link1
+                         link2
+                         link3
+
+                         ./subdir:
+                         subdirfile
+                         subsubdir
+
+                         ./subdir/subsubdir:
+                         """).strip())
+
+        # Check the correct inos were preserved by path
+        self.assertEqual(rootfile_ino, self.mount_a.path_to_ino("rootfile"))
+        self.assertEqual(subdir_ino, self.mount_a.path_to_ino("subdir"))
+        self.assertEqual(subdirfile_ino, self.mount_a.path_to_ino("subdir/subdirfile"))
+        self.assertEqual(subsubdir_ino, self.mount_a.path_to_ino("subdir/subsubdir"))
+
+        # Check that the hard link handling came out correctly
+        self.assertEqual(self.mount_a.path_to_ino("linkdir/link0"), subdirfile_ino)
+        self.assertEqual(self.mount_a.path_to_ino("linkdir/link1"), subdirfile_ino)
+        self.assertNotEqual(self.mount_a.path_to_ino("linkdir/link2"), subdirfile_ino)
+        self.assertEqual(self.mount_a.path_to_ino("linkdir/link3"), rootfile_ino)
+
+        # Create a new file, ensure it is not issued the same ino as one of the
+        # recovered ones
+        self.mount_a.run_shell(["touch", "afterwards"])
+        new_ino = self.mount_a.path_to_ino("afterwards")
+        self.assertNotIn(new_ino, [rootfile_ino, subdir_ino, subdirfile_ino])
+
+        # Check that we can do metadata ops in the recovered directory
+        self.mount_a.run_shell(["touch", "subdir/subsubdir/subsubdirfile"])
+
+    @for_teuthology # 308s
+    def test_reset(self):
+        """
+        That after forcibly modifying the backing store, we can get back into
+        a good state by resetting the MDSMap.
+
+        The scenario is that we have two active MDSs, and we lose the journals.  Once
+        we have completely lost confidence in the integrity of the metadata, we want to
+        return the system to a single-MDS state to go into a scrub to recover what we
+        can.
+        """
+
+        # Set max_mds to 2
+        self.fs.set_max_mds(2)
+
+        # See that we have two active MDSs
+        self.wait_until_equal(lambda: len(self.fs.get_active_names()), 2, 30,
+                              reject_fn=lambda v: v > 2 or v < 1)
+        active_mds_names = self.fs.get_active_names()
+
+        # Switch off any unneeded MDS daemons
+        for unneeded_mds in set(self.mds_cluster.mds_ids) - set(active_mds_names):
+            self.mds_cluster.mds_stop(unneeded_mds)
+            self.mds_cluster.mds_fail(unneeded_mds)
+
+        # Create a dir on each rank
+        self.mount_a.run_shell(["mkdir", "alpha"])
+        self.mount_a.run_shell(["mkdir", "bravo"])
+        self.mount_a.setfattr("alpha/", "ceph.dir.pin", "0")
+        self.mount_a.setfattr("bravo/", "ceph.dir.pin", "1")
+
+        def subtrees_assigned():
+            got_subtrees = self.fs.mds_asok(["get", "subtrees"], mds_id=active_mds_names[0])
+
+            for s in got_subtrees:
+                if s['dir']['path'] == '/bravo':
+                    if s['auth_first'] == 1:
+                        return True
+                    else:
+                        # Should not happen
+                        raise RuntimeError("/bravo is subtree but not rank 1!")
+
+            return False
+
+        # Ensure the pinning has taken effect and the /bravo dir is now
+        # migrated to rank 1.
+        self.wait_until_true(subtrees_assigned, 30)
+
+        # Do some IO (this should be split across ranks according to
+        # the rank-pinned dirs)
+        self.mount_a.create_n_files("alpha/file", 1000)
+        self.mount_a.create_n_files("bravo/file", 1000)
+
+        # Flush the journals so that we have some backing store data
+        # belonging to one MDS, and some to the other MDS.
+        for mds_name in active_mds_names:
+            self.fs.mds_asok(["flush", "journal"], mds_name)
+
+        # Stop (hard) the second MDS daemon
+        self.fs.mds_stop(active_mds_names[1])
+
+        # Wipe out the tables for MDS rank 1 so that it is broken and can't start
+        # (this is the simulated failure that we will demonstrate that the disaster
+        #  recovery tools can get us back from)
+        self.fs.erase_metadata_objects(prefix="mds1_")
+
+        # Try to access files from the client
+        blocked_ls = self.mount_a.run_shell(["ls", "-R"], wait=False)
+
+        # Check that this "ls -R" blocked rather than completing: indicates
+        # it got stuck trying to access subtrees which were on the now-dead MDS.
+        log.info("Sleeping to check ls is blocked...")
+        time.sleep(60)
+        self.assertFalse(blocked_ls.finished)
+
+        # This mount is now useless because it will depend on MDS rank 1, and MDS rank 1
+        # is not coming back.  Kill it.
+        log.info("Killing mount, it's blocked on the MDS we killed")
+        self.mount_a.kill()
+        self.mount_a.kill_cleanup()
+        try:
+            # Now that the mount is dead, the ls -R should error out.
+            blocked_ls.wait()
+        except (CommandFailedError, ConnectionLostError):
+            # The ConnectionLostError case is for kernel client, where
+            # killing the mount also means killing the node.
+            pass
+
+        # See that the second MDS will crash when it starts and tries to
+        # acquire rank 1
+        damaged_id = active_mds_names[1]
+        self.fs.mds_restart(damaged_id)
+
+        # The daemon taking the damaged rank should start starting, then
+        # restart back into standby after asking the mon to mark the rank
+        # damaged.
+        def is_marked_damaged():
+            mds_map = self.fs.get_mds_map()
+            return 1 in mds_map['damaged']
+
+        self.wait_until_true(is_marked_damaged, 60)
+
+        def get_state():
+            info = self.mds_cluster.get_mds_info(damaged_id)
+            return info['state'] if info is not None else None
+
+        self.wait_until_equal(
+                get_state,
+                "up:standby",
+                timeout=60)
+
+        self.fs.mds_stop(damaged_id)
+        self.fs.mds_fail(damaged_id)
+
+        # Now give up and go through a disaster recovery procedure
+        self.fs.mds_stop(active_mds_names[0])
+        self.fs.mds_fail(active_mds_names[0])
+        # Invoke recover_dentries quietly, because otherwise log spews millions of lines
+        self.fs.journal_tool(["event", "recover_dentries", "summary"], rank=0, quiet=True)
+        self.fs.journal_tool(["event", "recover_dentries", "summary"], rank=1, quiet=True)
+        self.fs.table_tool(["0", "reset", "session"])
+        self.fs.journal_tool(["journal", "reset"], rank=0)
+        self.fs.erase_mds_objects(1)
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'reset', self.fs.name,
+                '--yes-i-really-mean-it')
+
+        # Bring an MDS back online, mount a client, and see that we can walk the full
+        # filesystem tree again
+        self.fs.mds_fail_restart(active_mds_names[0])
+        self.wait_until_equal(lambda: self.fs.get_active_names(), [active_mds_names[0]], 30,
+                              reject_fn=lambda v: len(v) > 1)
+        self.mount_a.mount()
+        self.mount_a.run_shell(["ls", "-R"], wait=True)
+
+    def test_table_tool(self):
+        active_mdss = self.fs.get_active_names()
+        self.assertEqual(len(active_mdss), 1)
+        mds_name = active_mdss[0]
+
+        self.mount_a.run_shell(["touch", "foo"])
+        self.fs.mds_asok(["flush", "journal"], mds_name)
+
+        log.info(self.fs.table_tool(["all", "show", "inode"]))
+        log.info(self.fs.table_tool(["all", "show", "snap"]))
+        log.info(self.fs.table_tool(["all", "show", "session"]))
+
+        # Inode table should always be the same because initial state
+        # and choice of inode are deterministic.
+        # Should see one inode consumed
+        self.assertEqual(
+            json.loads(self.fs.table_tool(["all", "show", "inode"])),
+            {"0": {
+                "data": {
+                    "version": 2,
+                    "inotable": {
+                        "projected_free": [
+                            {"start": 1099511628777,
+                             "len": 1099511626775}],
+                        "free": [
+                            {"start": 1099511628777,
+                             "len": 1099511626775}]}},
+                "result": 0}}
+
+        )
+
+        # Should see one session
+        session_data = json.loads(self.fs.table_tool(
+            ["all", "show", "session"]))
+        self.assertEqual(len(session_data["0"]["data"]["Sessions"]), 1)
+        self.assertEqual(session_data["0"]["result"], 0)
+
+        # Should see no snaps
+        self.assertEqual(
+            json.loads(self.fs.table_tool(["all", "show", "snap"])),
+            {"version": 0,
+             "snapserver": {"last_snap": 1,
+                            "pending_noop": [],
+                            "snaps": [],
+                            "need_to_purge": {},
+                            "pending_update": [],
+                            "pending_destroy": []},
+             "result": 0}
+        )
+
+        # Reset everything
+        for table in ["session", "inode", "snap"]:
+            self.fs.table_tool(["all", "reset", table])
+
+        log.info(self.fs.table_tool(["all", "show", "inode"]))
+        log.info(self.fs.table_tool(["all", "show", "snap"]))
+        log.info(self.fs.table_tool(["all", "show", "session"]))
+
+        # Should see 0 sessions
+        session_data = json.loads(self.fs.table_tool(
+            ["all", "show", "session"]))
+        self.assertEqual(len(session_data["0"]["data"]["Sessions"]), 0)
+        self.assertEqual(session_data["0"]["result"], 0)
+
+        # Should see entire inode range now marked free
+        self.assertEqual(
+            json.loads(self.fs.table_tool(["all", "show", "inode"])),
+            {"0": {"data": {"version": 1,
+                            "inotable": {"projected_free": [
+                                {"start": 1099511627776,
+                                 "len": 1099511627776}],
+                                 "free": [
+                                    {"start": 1099511627776,
+                                    "len": 1099511627776}]}},
+                   "result": 0}}
+        )
+
+        # Should see no snaps
+        self.assertEqual(
+            json.loads(self.fs.table_tool(["all", "show", "snap"])),
+            {"version": 1,
+             "snapserver": {"last_snap": 1,
+                            "pending_noop": [],
+                            "snaps": [],
+                            "need_to_purge": {},
+                            "pending_update": [],
+                            "pending_destroy": []},
+             "result": 0}
+        )
+
+    def test_table_tool_take_inos(self):
+        initial_range_start = 1099511627776
+        initial_range_len = 1099511627776
+        # Initially a completely clear range
+        self.assertEqual(
+            json.loads(self.fs.table_tool(["all", "show", "inode"])),
+            {"0": {"data": {"version": 0,
+                            "inotable": {"projected_free": [
+                                {"start": initial_range_start,
+                                 "len": initial_range_len}],
+                                "free": [
+                                    {"start": initial_range_start,
+                                     "len": initial_range_len}]}},
+                   "result": 0}}
+        )
+
+        # Remove some
+        self.assertEqual(
+            json.loads(self.fs.table_tool(["all", "take_inos", "{0}".format(initial_range_start + 100)])),
+            {"0": {"data": {"version": 1,
+                            "inotable": {"projected_free": [
+                                {"start": initial_range_start + 101,
+                                 "len": initial_range_len - 101}],
+                                "free": [
+                                    {"start": initial_range_start + 101,
+                                     "len": initial_range_len - 101}]}},
+                   "result": 0}}
+        )
+
+    @for_teuthology  # Hack: "for_teuthology" because .sh doesn't work outside teuth
+    def test_journal_smoke(self):
+        workunit(self.ctx, {
+            'clients': {
+                "client.{0}".format(self.mount_a.client_id): [
+                    "fs/misc/trivial_sync.sh"],
+            },
+            "timeout": "1h"
+        })
+
+        for mount in self.mounts:
+            mount.umount_wait()
+
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        # journal tool smoke
+        workunit(self.ctx, {
+            'clients': {
+                "client.{0}".format(self.mount_a.client_id): [
+                    "suites/cephfs_journal_tool_smoke.sh"],
+            },
+            "timeout": "1h"
+        })
+
+
+
+        self.fs.mds_restart()
+        self.fs.wait_for_daemons()
+
+        self.mount_a.mount()
+
+        # trivial sync moutn a
+        workunit(self.ctx, {
+            'clients': {
+                "client.{0}".format(self.mount_a.client_id): [
+                    "fs/misc/trivial_sync.sh"],
+            },
+            "timeout": "1h"
+        })
+
diff --git a/src/ceph/qa/tasks/cephfs/test_mantle.py b/src/ceph/qa/tasks/cephfs/test_mantle.py
new file mode 100644
index 0000000..6cd86ad
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_mantle.py
@@ -0,0 +1,109 @@
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+import json
+import logging
+
+log = logging.getLogger(__name__)
+failure = "using old balancer; mantle failed for balancer="
+success = "mantle balancer version changed: "
+
+class TestMantle(CephFSTestCase):
+    def start_mantle(self):
+        self.wait_for_health_clear(timeout=30)
+        self.fs.set_max_mds(2)
+        self.wait_until_equal(lambda: len(self.fs.get_active_names()), 2, 30,
+                              reject_fn=lambda v: v > 2 or v < 1)
+
+        for m in self.fs.get_active_names():
+            self.fs.mds_asok(['config', 'set', 'debug_objecter', '20'], mds_id=m)
+            self.fs.mds_asok(['config', 'set', 'debug_ms', '0'], mds_id=m)
+            self.fs.mds_asok(['config', 'set', 'debug_mds', '0'], mds_id=m)
+            self.fs.mds_asok(['config', 'set', 'debug_mds_balancer', '5'], mds_id=m)
+
+    def push_balancer(self, obj, lua_code, expect):
+        self.fs.mon_manager.raw_cluster_cmd_result('fs', 'set', self.fs.name, 'balancer', obj)
+        self.fs.rados(["put", obj, "-"], stdin_data=lua_code)
+        with self.assert_cluster_log(failure + obj + " " + expect):
+            log.info("run a " + obj + " balancer that expects=" + expect)
+
+    def test_version_empty(self):
+        self.start_mantle()
+        expect = " : (2) No such file or directory"
+
+        ret = self.fs.mon_manager.raw_cluster_cmd_result('fs', 'set', self.fs.name, 'balancer')
+        assert(ret == 22) # EINVAL
+
+        self.fs.mon_manager.raw_cluster_cmd_result('fs', 'set', self.fs.name, 'balancer', " ")
+        with self.assert_cluster_log(failure + " " + expect): pass
+
+    def test_version_not_in_rados(self):
+        self.start_mantle()
+        expect = failure + "ghost.lua : (2) No such file or directory"
+        self.fs.mon_manager.raw_cluster_cmd_result('fs', 'set', self.fs.name, 'balancer', "ghost.lua")
+        with self.assert_cluster_log(expect): pass
+
+    def test_balancer_invalid(self):
+        self.start_mantle()
+        expect = ": (22) Invalid argument"
+
+        lua_code = "this is invalid lua code!"
+        self.push_balancer("invalid.lua", lua_code, expect)
+
+        lua_code = "BAL_LOG()"
+        self.push_balancer("invalid_log.lua", lua_code, expect)
+
+        lua_code = "BAL_LOG(0)"
+        self.push_balancer("invalid_log_again.lua", lua_code, expect)
+
+    def test_balancer_valid(self):
+        self.start_mantle()
+        lua_code = "BAL_LOG(0, \"test\")\nreturn {3, 4}"
+        self.fs.mon_manager.raw_cluster_cmd_result('fs', 'set', self.fs.name, 'balancer', "valid.lua")
+        self.fs.rados(["put", "valid.lua", "-"], stdin_data=lua_code)
+        with self.assert_cluster_log(success + "valid.lua"):
+            log.info("run a valid.lua balancer")
+
+    def test_return_invalid(self):
+        self.start_mantle()
+        expect = ": (22) Invalid argument"
+
+        lua_code = "return \"hello\""
+        self.push_balancer("string.lua", lua_code, expect)
+
+        lua_code = "return 3"
+        self.push_balancer("number.lua", lua_code, expect)
+
+        lua_code = "return {}"
+        self.push_balancer("dict_empty.lua", lua_code, expect)
+
+        lua_code = "return {\"this\", \"is\", \"a\", \"test\"}"
+        self.push_balancer("dict_of_strings.lua", lua_code, expect)
+
+        lua_code = "return {3, \"test\"}"
+        self.push_balancer("dict_of_mixed.lua", lua_code, expect)
+
+        lua_code = "return {3}"
+        self.push_balancer("not_enough_numbers.lua", lua_code, expect)
+
+        lua_code = "return {3, 4, 5, 6, 7, 8, 9}"
+        self.push_balancer("too_many_numbers.lua", lua_code, expect)
+
+    def test_dead_osd(self):
+        self.start_mantle()
+        expect = " : (110) Connection timed out"
+
+        # kill the OSDs so that the balancer pull from RADOS times out
+        osd_map = json.loads(self.fs.mon_manager.raw_cluster_cmd('osd', 'dump', '--format=json-pretty'))
+        for i in range(0, len(osd_map['osds'])):
+          self.fs.mon_manager.raw_cluster_cmd_result('osd', 'down', str(i))
+          self.fs.mon_manager.raw_cluster_cmd_result('osd', 'out', str(i))
+
+        # trigger a pull from RADOS
+        self.fs.mon_manager.raw_cluster_cmd_result('fs', 'set', self.fs.name, 'balancer', "valid.lua")
+
+        # make the timeout a little longer since dead OSDs spam ceph -w
+        with self.assert_cluster_log(failure + "valid.lua" + expect, timeout=30):
+            log.info("run a balancer that should timeout")
+
+        # cleanup
+        for i in range(0, len(osd_map['osds'])):
+          self.fs.mon_manager.raw_cluster_cmd_result('osd', 'in', str(i))
diff --git a/src/ceph/qa/tasks/cephfs/test_misc.py b/src/ceph/qa/tasks/cephfs/test_misc.py
new file mode 100644
index 0000000..d857cfd
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_misc.py
@@ -0,0 +1,149 @@
+
+from unittest import SkipTest
+from tasks.cephfs.fuse_mount import FuseMount
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+from teuthology.orchestra.run import CommandFailedError
+import errno
+import time
+import json
+
+
+class TestMisc(CephFSTestCase):
+    CLIENTS_REQUIRED = 2
+
+    LOAD_SETTINGS = ["mds_session_autoclose"]
+    mds_session_autoclose = None
+
+    def test_getattr_caps(self):
+        """
+        Check if MDS recognizes the 'mask' parameter of open request.
+        The paramter allows client to request caps when opening file
+        """
+
+        if not isinstance(self.mount_a, FuseMount):
+            raise SkipTest("Require FUSE client")
+
+        # Enable debug. Client will requests CEPH_CAP_XATTR_SHARED
+        # on lookup/open
+        self.mount_b.umount_wait()
+        self.set_conf('client', 'client debug getattr caps', 'true')
+        self.mount_b.mount()
+        self.mount_b.wait_until_mounted()
+
+        # create a file and hold it open. MDS will issue CEPH_CAP_EXCL_*
+        # to mount_a
+        p = self.mount_a.open_background("testfile")
+        self.mount_b.wait_for_visible("testfile")
+
+        # this tiggers a lookup request and an open request. The debug
+        # code will check if lookup/open reply contains xattrs
+        self.mount_b.run_shell(["cat", "testfile"])
+
+        self.mount_a.kill_background(p)
+
+    def test_fs_new(self):
+        data_pool_name = self.fs.get_data_pool_name()
+
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'rm', self.fs.name,
+                                            '--yes-i-really-mean-it')
+
+        self.fs.mon_manager.raw_cluster_cmd('osd', 'pool', 'delete',
+                                            self.fs.metadata_pool_name,
+                                            self.fs.metadata_pool_name,
+                                            '--yes-i-really-really-mean-it')
+        self.fs.mon_manager.raw_cluster_cmd('osd', 'pool', 'create',
+                                            self.fs.metadata_pool_name,
+                                            self.fs.get_pgs_per_fs_pool().__str__())
+
+        dummyfile = '/etc/fstab'
+
+        self.fs.put_metadata_object_raw("key", dummyfile)
+
+        def get_pool_df(fs, name):
+            try:
+                return fs.get_pool_df(name)['objects'] > 0
+            except RuntimeError as e:
+                return False
+
+        self.wait_until_true(lambda: get_pool_df(self.fs, self.fs.metadata_pool_name), timeout=30)
+
+        try:
+            self.fs.mon_manager.raw_cluster_cmd('fs', 'new', self.fs.name,
+                                                self.fs.metadata_pool_name,
+                                                data_pool_name)
+        except CommandFailedError as e:
+            self.assertEqual(e.exitstatus, errno.EINVAL)
+        else:
+            raise AssertionError("Expected EINVAL")
+
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'new', self.fs.name,
+                                            self.fs.metadata_pool_name,
+                                            data_pool_name, "--force")
+
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'rm', self.fs.name,
+                                            '--yes-i-really-mean-it')
+
+
+        self.fs.mon_manager.raw_cluster_cmd('osd', 'pool', 'delete',
+                                            self.fs.metadata_pool_name,
+                                            self.fs.metadata_pool_name,
+                                            '--yes-i-really-really-mean-it')
+        self.fs.mon_manager.raw_cluster_cmd('osd', 'pool', 'create',
+                                            self.fs.metadata_pool_name,
+                                            self.fs.get_pgs_per_fs_pool().__str__())
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'new', self.fs.name,
+                                            self.fs.metadata_pool_name,
+                                            data_pool_name)
+
+    def test_evict_client(self):
+        """
+        Check that a slow client session won't get evicted if it's the
+        only session
+        """
+
+        self.mount_b.umount_wait()
+        ls_data = self.fs.mds_asok(['session', 'ls'])
+        self.assert_session_count(1, ls_data)
+
+        self.mount_a.kill()
+        self.mount_a.kill_cleanup()
+
+        time.sleep(self.mds_session_autoclose * 1.5)
+        ls_data = self.fs.mds_asok(['session', 'ls'])
+        self.assert_session_count(1, ls_data)
+
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        self.mount_b.mount()
+        self.mount_b.wait_until_mounted()
+
+        ls_data = self._session_list()
+        self.assert_session_count(2, ls_data)
+
+        self.mount_a.kill()
+        self.mount_a.kill_cleanup()
+
+        time.sleep(self.mds_session_autoclose * 1.5)
+        ls_data = self.fs.mds_asok(['session', 'ls'])
+        self.assert_session_count(1, ls_data)
+
+    def test_filtered_df(self):
+        pool_name = self.fs.get_data_pool_name()
+        raw_df = self.fs.get_pool_df(pool_name)
+        raw_avail = float(raw_df["max_avail"])
+        out = self.fs.mon_manager.raw_cluster_cmd('osd', 'pool', 'get',
+                                                  pool_name, 'size',
+                                                  '-f', 'json-pretty')
+        j = json.loads(out)
+        pool_size = int(j['size'])
+
+        proc = self.mount_a.run_shell(['df', '.'])
+        output = proc.stdout.getvalue()
+        fs_avail = output.split('\n')[1].split()[3]
+        fs_avail = float(fs_avail) * 1024
+
+        ratio = raw_avail / fs_avail
+        assert 0.9 < ratio < 1.1
diff --git a/src/ceph/qa/tasks/cephfs/test_pool_perm.py b/src/ceph/qa/tasks/cephfs/test_pool_perm.py
new file mode 100644
index 0000000..22775e7
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_pool_perm.py
@@ -0,0 +1,113 @@
+from textwrap import dedent
+from teuthology.exceptions import CommandFailedError
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+import os
+
+
+class TestPoolPerm(CephFSTestCase):
+    def test_pool_perm(self):
+        self.mount_a.run_shell(["touch", "test_file"])
+
+        file_path = os.path.join(self.mount_a.mountpoint, "test_file")
+
+        remote_script = dedent("""
+            import os
+            import errno
+
+            fd = os.open("{path}", os.O_RDWR)
+            try:
+                if {check_read}:
+                    ret = os.read(fd, 1024)
+                else:
+                    os.write(fd, 'content')
+            except OSError, e:
+                if e.errno != errno.EPERM:
+                    raise
+            else:
+                raise RuntimeError("client does not check permission of data pool")
+            """)
+
+        client_name = "client.{0}".format(self.mount_a.client_id)
+
+        # set data pool read only
+        self.fs.mon_manager.raw_cluster_cmd_result(
+            'auth', 'caps', client_name, 'mds', 'allow', 'mon', 'allow r', 'osd',
+            'allow r pool={0}'.format(self.fs.get_data_pool_name()))
+
+        self.mount_a.umount_wait()
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        # write should fail
+        self.mount_a.run_python(remote_script.format(path=file_path, check_read=str(False)))
+
+        # set data pool write only
+        self.fs.mon_manager.raw_cluster_cmd_result(
+            'auth', 'caps', client_name, 'mds', 'allow', 'mon', 'allow r', 'osd',
+            'allow w pool={0}'.format(self.fs.get_data_pool_name()))
+
+        self.mount_a.umount_wait()
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        # read should fail
+        self.mount_a.run_python(remote_script.format(path=file_path, check_read=str(True)))
+
+    def test_forbidden_modification(self):
+        """
+        That a client who does not have the capability for setting
+        layout pools is prevented from doing so.
+        """
+
+        # Set up
+        client_name = "client.{0}".format(self.mount_a.client_id)
+        new_pool_name = "data_new"
+        self.fs.add_data_pool(new_pool_name)
+
+        self.mount_a.run_shell(["touch", "layoutfile"])
+        self.mount_a.run_shell(["mkdir", "layoutdir"])
+
+        # Set MDS 'rw' perms: missing 'p' means no setting pool layouts
+        self.fs.mon_manager.raw_cluster_cmd_result(
+            'auth', 'caps', client_name, 'mds', 'allow rw', 'mon', 'allow r',
+            'osd',
+            'allow rw pool={0},allow rw pool={1}'.format(
+                self.fs.get_data_pool_names()[0],
+                self.fs.get_data_pool_names()[1],
+            ))
+
+        self.mount_a.umount_wait()
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        with self.assertRaises(CommandFailedError):
+            self.mount_a.setfattr("layoutfile", "ceph.file.layout.pool",
+                                  new_pool_name)
+        with self.assertRaises(CommandFailedError):
+            self.mount_a.setfattr("layoutdir", "ceph.dir.layout.pool",
+                                  new_pool_name)
+        self.mount_a.umount_wait()
+
+        # Set MDS 'rwp' perms: should now be able to set layouts
+        self.fs.mon_manager.raw_cluster_cmd_result(
+            'auth', 'caps', client_name, 'mds', 'allow rwp', 'mon', 'allow r',
+            'osd',
+            'allow rw pool={0},allow rw pool={1}'.format(
+                self.fs.get_data_pool_names()[0],
+                self.fs.get_data_pool_names()[1],
+            ))
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        self.mount_a.setfattr("layoutfile", "ceph.file.layout.pool",
+                              new_pool_name)
+        self.mount_a.setfattr("layoutdir", "ceph.dir.layout.pool",
+                              new_pool_name)
+        self.mount_a.umount_wait()
+
+    def tearDown(self):
+        self.fs.mon_manager.raw_cluster_cmd_result(
+            'auth', 'caps', "client.{0}".format(self.mount_a.client_id),
+            'mds', 'allow', 'mon', 'allow r', 'osd',
+            'allow rw pool={0}'.format(self.fs.get_data_pool_names()[0]))
+        super(TestPoolPerm, self).tearDown()
+
diff --git a/src/ceph/qa/tasks/cephfs/test_quota.py b/src/ceph/qa/tasks/cephfs/test_quota.py
new file mode 100644
index 0000000..ee11c58
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_quota.py
@@ -0,0 +1,106 @@
+
+from cephfs_test_case import CephFSTestCase
+
+from teuthology.exceptions import CommandFailedError
+
+class TestQuota(CephFSTestCase):
+    CLIENTS_REQUIRED = 2
+    MDSS_REQUIRED = 1
+
+    def test_remote_update_getfattr(self):
+        """
+        That quota changes made from one client are visible to another
+        client looking at ceph.quota xattrs
+        """
+        self.mount_a.run_shell(["mkdir", "subdir"])
+
+        self.assertEqual(
+            self.mount_a.getfattr("./subdir", "ceph.quota.max_files"),
+            None)
+        self.assertEqual(
+            self.mount_b.getfattr("./subdir", "ceph.quota.max_files"),
+            None)
+
+        self.mount_a.setfattr("./subdir", "ceph.quota.max_files", "10")
+        self.assertEqual(
+            self.mount_a.getfattr("./subdir", "ceph.quota.max_files"),
+            "10")
+
+        # Should be visible as soon as setxattr operation completes on
+        # mds (we get here sooner because setfattr gets an early reply)
+        self.wait_until_equal(
+            lambda: self.mount_b.getfattr("./subdir", "ceph.quota.max_files"),
+            "10", timeout=10)
+
+    def test_remote_update_df(self):
+        """
+        That when a client modifies the quota on a directory used
+        as another client's root, the other client sees the change
+        reflected in their statfs output.
+        """
+
+        self.mount_b.umount_wait()
+
+        self.mount_a.run_shell(["mkdir", "subdir"])
+
+        size_before = 1024 * 1024 * 128
+        self.mount_a.setfattr("./subdir", "ceph.quota.max_bytes",
+                              "%s" % size_before)
+
+        self.mount_b.mount(mount_path="/subdir")
+
+        self.assertDictEqual(
+            self.mount_b.df(),
+            {
+                "total": size_before,
+                "used": 0,
+                "available": size_before
+            })
+
+        size_after = 1024 * 1024 * 256
+        self.mount_a.setfattr("./subdir", "ceph.quota.max_bytes",
+                              "%s" % size_after)
+
+        # Should be visible as soon as setxattr operation completes on
+        # mds (we get here sooner because setfattr gets an early reply)
+        self.wait_until_equal(
+            lambda: self.mount_b.df(),
+            {
+                "total": size_after,
+                "used": 0,
+                "available": size_after
+            },
+            timeout=10
+        )
+
+    def test_remote_update_write(self):
+        """
+        That when a client modifies the quota on a directory used
+        as another client's root, the other client sees the effect
+        of the change when writing data.
+        """
+
+        self.mount_a.run_shell(["mkdir", "subdir_files"])
+        self.mount_a.run_shell(["mkdir", "subdir_data"])
+
+        # Set some nice high quotas that mount_b's initial operations
+        # will be well within
+        self.mount_a.setfattr("./subdir_files", "ceph.quota.max_files", "100")
+        self.mount_a.setfattr("./subdir_data", "ceph.quota.max_bytes", "104857600")
+
+        # Do some writes within my quota
+        self.mount_b.create_n_files("subdir_files/file", 20)
+        self.mount_b.write_n_mb("subdir_data/file", 20)
+
+        # Set quotas lower than what mount_b already wrote, it should
+        # refuse to write more once it's seen them
+        self.mount_a.setfattr("./subdir_files", "ceph.quota.max_files", "10")
+        self.mount_a.setfattr("./subdir_data", "ceph.quota.max_bytes", "1048576")
+
+        # Do some writes that would have been okay within the old quota,
+        # but are forbidden under the new quota
+        with self.assertRaises(CommandFailedError):
+            self.mount_b.create_n_files("subdir_files/file", 40)
+        with self.assertRaises(CommandFailedError):
+            self.mount_b.write_n_mb("subdir_data/file", 40)
+
diff --git a/src/ceph/qa/tasks/cephfs/test_readahead.py b/src/ceph/qa/tasks/cephfs/test_readahead.py
new file mode 100644
index 0000000..31e7bf1
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_readahead.py
@@ -0,0 +1,31 @@
+import logging
+from tasks.cephfs.fuse_mount import FuseMount
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+
+log = logging.getLogger(__name__)
+
+
+class TestReadahead(CephFSTestCase):
+    def test_flush(self):
+        if not isinstance(self.mount_a, FuseMount):
+            self.skipTest("FUSE needed for measuring op counts")
+
+        # Create 32MB file
+        self.mount_a.run_shell(["dd", "if=/dev/urandom", "of=foo", "bs=1M", "count=32"])
+
+        # Unmount and remount the client to flush cache
+        self.mount_a.umount_wait()
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        initial_op_r = self.mount_a.admin_socket(['perf', 'dump', 'objecter'])['objecter']['op_r']
+        self.mount_a.run_shell(["dd", "if=foo", "of=/dev/null", "bs=128k", "count=32"])
+        op_r = self.mount_a.admin_socket(['perf', 'dump', 'objecter'])['objecter']['op_r']
+        assert op_r >= initial_op_r
+        op_r -= initial_op_r
+        log.info("read operations: {0}".format(op_r))
+
+        # with exponentially increasing readahead, we should see fewer than 10 operations
+        # but this test simply checks if the client is doing a remote read for each local read
+        if op_r >= 32:
+            raise RuntimeError("readahead not working")
diff --git a/src/ceph/qa/tasks/cephfs/test_recovery_pool.py b/src/ceph/qa/tasks/cephfs/test_recovery_pool.py
new file mode 100644
index 0000000..097342a
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_recovery_pool.py
@@ -0,0 +1,220 @@
+
+"""
+Test our tools for recovering metadata from the data pool into an alternate pool
+"""
+import json
+
+import logging
+import os
+from textwrap import dedent
+import traceback
+from collections import namedtuple, defaultdict
+
+from teuthology.orchestra.run import CommandFailedError
+from tasks.cephfs.cephfs_test_case import CephFSTestCase, for_teuthology
+
+log = logging.getLogger(__name__)
+
+
+ValidationError = namedtuple("ValidationError", ["exception", "backtrace"])
+
+
+class OverlayWorkload(object):
+    def __init__(self, orig_fs, recovery_fs, orig_mount, recovery_mount):
+        self._orig_fs = orig_fs
+        self._recovery_fs = recovery_fs
+        self._orig_mount = orig_mount
+        self._recovery_mount = recovery_mount
+        self._initial_state = None
+
+        # Accumulate backtraces for every failed validation, and return them.  Backtraces
+        # are rather verbose, but we only see them when something breaks, and they
+        # let us see which check failed without having to decorate each check with
+        # a string
+        self._errors = []
+
+    def assert_equal(self, a, b):
+        try:
+            if a != b:
+                raise AssertionError("{0} != {1}".format(a, b))
+        except AssertionError as e:
+            self._errors.append(
+                ValidationError(e, traceback.format_exc(3))
+            )
+
+    def write(self):
+        """
+        Write the workload files to the mount
+        """
+        raise NotImplementedError()
+
+    def validate(self):
+        """
+        Read from the mount and validate that the workload files are present (i.e. have
+        survived or been reconstructed from the test scenario)
+        """
+        raise NotImplementedError()
+
+    def damage(self):
+        """
+        Damage the filesystem pools in ways that will be interesting to recover from.  By
+        default just wipe everything in the metadata pool
+        """
+        # Delete every object in the metadata pool
+        objects = self._orig_fs.rados(["ls"]).split("\n")
+        for o in objects:
+            self._orig_fs.rados(["rm", o])
+
+    def flush(self):
+        """
+        Called after client unmount, after write: flush whatever you want
+        """
+        self._orig_fs.mds_asok(["flush", "journal"])
+        self._recovery_fs.mds_asok(["flush", "journal"])
+
+
+class SimpleOverlayWorkload(OverlayWorkload):
+    """
+    Single file, single directory, check that it gets recovered and so does its size
+    """
+    def write(self):
+        self._orig_mount.run_shell(["mkdir", "subdir"])
+        self._orig_mount.write_n_mb("subdir/sixmegs", 6)
+        self._initial_state = self._orig_mount.stat("subdir/sixmegs")
+
+    def validate(self):
+        self._recovery_mount.run_shell(["ls", "subdir"])
+        st = self._recovery_mount.stat("subdir/sixmegs")
+        self.assert_equal(st['st_size'], self._initial_state['st_size'])
+        return self._errors
+
+class TestRecoveryPool(CephFSTestCase):
+    MDSS_REQUIRED = 2
+    CLIENTS_REQUIRED = 2
+    REQUIRE_RECOVERY_FILESYSTEM = True
+
+    def is_marked_damaged(self, rank):
+        mds_map = self.fs.get_mds_map()
+        return rank in mds_map['damaged']
+
+    def _rebuild_metadata(self, workload, other_pool=None, workers=1):
+        """
+        That when all objects in metadata pool are removed, we can rebuild a metadata pool
+        based on the contents of a data pool, and a client can see and read our files.
+        """
+
+        # First, inject some files
+
+        workload.write()
+
+        # Unmount the client and flush the journal: the tool should also cope with
+        # situations where there is dirty metadata, but we'll test that separately
+        self.mount_a.umount_wait()
+        self.mount_b.umount_wait()
+        workload.flush()
+
+        # Create the alternate pool if requested
+        recovery_fs = self.recovery_fs.name
+        recovery_pool = self.recovery_fs.get_metadata_pool_name()
+        self.recovery_fs.data_scan(['init', '--force-init',
+                                    '--filesystem', recovery_fs,
+                                    '--alternate-pool', recovery_pool])
+        self.recovery_fs.mon_manager.raw_cluster_cmd('-s')
+        self.recovery_fs.table_tool([recovery_fs + ":0", "reset", "session"])
+        self.recovery_fs.table_tool([recovery_fs + ":0", "reset", "snap"])
+        self.recovery_fs.table_tool([recovery_fs + ":0", "reset", "inode"])
+
+        # Stop the MDS
+        self.fs.mds_stop()
+        self.fs.mds_fail()
+
+        # After recovery, we need the MDS to not be strict about stats (in production these options
+        # are off by default, but in QA we need to explicitly disable them)
+        self.fs.set_ceph_conf('mds', 'mds verify scatter', False)
+        self.fs.set_ceph_conf('mds', 'mds debug scatterstat', False)
+
+        # Apply any data damage the workload wants
+        workload.damage()
+
+        # Reset the MDS map in case multiple ranks were in play: recovery procedure
+        # only understands how to rebuild metadata under rank 0
+        self.fs.mon_manager.raw_cluster_cmd('fs', 'reset', self.fs.name,
+                '--yes-i-really-mean-it')
+
+        def get_state(mds_id):
+            info = self.mds_cluster.get_mds_info(mds_id)
+            return info['state'] if info is not None else None
+
+        self.fs.table_tool([self.fs.name + ":0", "reset", "session"])
+        self.fs.table_tool([self.fs.name + ":0", "reset", "snap"])
+        self.fs.table_tool([self.fs.name + ":0", "reset", "inode"])
+
+        # Run the recovery procedure
+        if False:
+            with self.assertRaises(CommandFailedError):
+                # Normal reset should fail when no objects are present, we'll use --force instead
+                self.fs.journal_tool(["journal", "reset"])
+
+        self.fs.mds_stop()
+        self.fs.data_scan(['scan_extents', '--alternate-pool',
+                           recovery_pool, '--filesystem', self.fs.name,
+                           self.fs.get_data_pool_name()])
+        self.fs.data_scan(['scan_inodes', '--alternate-pool',
+                           recovery_pool, '--filesystem', self.fs.name,
+                           '--force-corrupt', '--force-init',
+                           self.fs.get_data_pool_name()])
+        self.fs.journal_tool(['--rank=' + self.fs.name + ":0", 'event',
+                              'recover_dentries', 'list',
+                              '--alternate-pool', recovery_pool])
+
+        self.fs.data_scan(['init', '--force-init', '--filesystem',
+                           self.fs.name])
+        self.fs.data_scan(['scan_inodes', '--filesystem', self.fs.name,
+                           '--force-corrupt', '--force-init',
+                           self.fs.get_data_pool_name()])
+        self.fs.journal_tool(['--rank=' + self.fs.name + ":0", 'event',
+                              'recover_dentries', 'list'])
+
+        self.fs.journal_tool(['--rank=' + recovery_fs + ":0", 'journal',
+                              'reset', '--force'])
+        self.fs.journal_tool(['--rank=' + self.fs.name + ":0", 'journal',
+                              'reset', '--force'])
+        self.fs.mon_manager.raw_cluster_cmd('mds', 'repaired',
+                                            recovery_fs + ":0")
+
+        # Mark the MDS repaired
+        self.fs.mon_manager.raw_cluster_cmd('mds', 'repaired', '0')
+
+        # Start the MDS
+        self.fs.mds_restart()
+        self.recovery_fs.mds_restart()
+        self.fs.wait_for_daemons()
+        self.recovery_fs.wait_for_daemons()
+        for mds_id in self.recovery_fs.mds_ids:
+            self.fs.mon_manager.raw_cluster_cmd('tell', "mds." + mds_id,
+                                                'injectargs', '--debug-mds=20')
+            self.fs.mon_manager.raw_cluster_cmd('daemon', "mds." + mds_id,
+                                                'scrub_path', '/',
+                                                'recursive', 'repair')
+        log.info(str(self.mds_cluster.status()))
+
+        # Mount a client
+        self.mount_a.mount()
+        self.mount_b.mount(mount_fs_name=recovery_fs)
+        self.mount_a.wait_until_mounted()
+        self.mount_b.wait_until_mounted()
+
+        # See that the files are present and correct
+        errors = workload.validate()
+        if errors:
+            log.error("Validation errors found: {0}".format(len(errors)))
+            for e in errors:
+                log.error(e.exception)
+                log.error(e.backtrace)
+            raise AssertionError("Validation failed, first error: {0}\n{1}".format(
+                errors[0].exception, errors[0].backtrace
+            ))
+
+    def test_rebuild_simple(self):
+        self._rebuild_metadata(SimpleOverlayWorkload(self.fs, self.recovery_fs,
+                                                     self.mount_a, self.mount_b))
diff --git a/src/ceph/qa/tasks/cephfs/test_scrub_checks.py b/src/ceph/qa/tasks/cephfs/test_scrub_checks.py
new file mode 100644
index 0000000..a2de527
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_scrub_checks.py
@@ -0,0 +1,245 @@
+"""
+MDS admin socket scrubbing-related tests.
+"""
+import json
+import logging
+import errno
+import time
+from teuthology.exceptions import CommandFailedError
+import os
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+
+log = logging.getLogger(__name__)
+
+
+class TestScrubChecks(CephFSTestCase):
+    """
+    Run flush and scrub commands on the specified files in the filesystem. This
+    task will run through a sequence of operations, but it is not comprehensive
+    on its own -- it doesn't manipulate the mds cache state to test on both
+    in- and out-of-memory parts of the hierarchy. So it's designed to be run
+    multiple times within a single test run, so that the test can manipulate
+    memory state.
+
+    Usage:
+    mds_scrub_checks:
+      mds_rank: 0
+      path: path/to/test/dir
+      client: 0
+      run_seq: [0-9]+
+
+    Increment the run_seq on subsequent invocations within a single test run;
+    it uses that value to generate unique folder and file names.
+    """
+
+    MDSS_REQUIRED = 1
+    CLIENTS_REQUIRED = 1
+
+    def test_scrub_checks(self):
+        self._checks(0)
+        self._checks(1)
+
+    def _checks(self, run_seq):
+        mds_rank = 0
+        test_dir = "scrub_test_path"
+
+        abs_test_path = "/{0}".format(test_dir)
+
+        log.info("mountpoint: {0}".format(self.mount_a.mountpoint))
+        client_path = os.path.join(self.mount_a.mountpoint, test_dir)
+        log.info("client_path: {0}".format(client_path))
+
+        log.info("Cloning repo into place")
+        repo_path = self.clone_repo(self.mount_a, client_path)
+
+        log.info("Initiating mds_scrub_checks on mds.{id_}, " +
+                 "test_path {path}, run_seq {seq}".format(
+                     id_=mds_rank, path=abs_test_path, seq=run_seq)
+                 )
+
+
+        success_validator = lambda j, r: self.json_validator(j, r, "return_code", 0)
+
+        nep = "{test_path}/i/dont/exist".format(test_path=abs_test_path)
+        self.asok_command(mds_rank, "flush_path {nep}".format(nep=nep),
+                          lambda j, r: self.json_validator(j, r, "return_code", -errno.ENOENT))
+        self.asok_command(mds_rank, "scrub_path {nep}".format(nep=nep),
+                          lambda j, r: self.json_validator(j, r, "return_code", -errno.ENOENT))
+
+        test_repo_path = "{test_path}/ceph-qa-suite".format(test_path=abs_test_path)
+        dirpath = "{repo_path}/suites".format(repo_path=test_repo_path)
+
+        if run_seq == 0:
+            log.info("First run: flushing {dirpath}".format(dirpath=dirpath))
+            command = "flush_path {dirpath}".format(dirpath=dirpath)
+            self.asok_command(mds_rank, command, success_validator)
+        command = "scrub_path {dirpath}".format(dirpath=dirpath)
+        self.asok_command(mds_rank, command, success_validator)
+
+        filepath = "{repo_path}/suites/fs/verify/validater/valgrind.yaml".format(
+            repo_path=test_repo_path)
+        if run_seq == 0:
+            log.info("First run: flushing {filepath}".format(filepath=filepath))
+            command = "flush_path {filepath}".format(filepath=filepath)
+            self.asok_command(mds_rank, command, success_validator)
+        command = "scrub_path {filepath}".format(filepath=filepath)
+        self.asok_command(mds_rank, command, success_validator)
+
+        filepath = "{repo_path}/suites/fs/basic/clusters/fixed-3-cephfs.yaml". \
+            format(repo_path=test_repo_path)
+        command = "scrub_path {filepath}".format(filepath=filepath)
+        self.asok_command(mds_rank, command,
+                          lambda j, r: self.json_validator(j, r, "performed_validation",
+                                                           False))
+
+        if run_seq == 0:
+            log.info("First run: flushing base dir /")
+            command = "flush_path /"
+            self.asok_command(mds_rank, command, success_validator)
+        command = "scrub_path /"
+        self.asok_command(mds_rank, command, success_validator)
+
+        new_dir = "{repo_path}/new_dir_{i}".format(repo_path=repo_path, i=run_seq)
+        test_new_dir = "{repo_path}/new_dir_{i}".format(repo_path=test_repo_path,
+                                                        i=run_seq)
+        self.mount_a.run_shell(["mkdir", new_dir])
+        command = "flush_path {dir}".format(dir=test_new_dir)
+        self.asok_command(mds_rank, command, success_validator)
+
+        new_file = "{repo_path}/new_file_{i}".format(repo_path=repo_path,
+                                                     i=run_seq)
+        test_new_file = "{repo_path}/new_file_{i}".format(repo_path=test_repo_path,
+                                                          i=run_seq)
+        self.mount_a.write_n_mb(new_file, 1)
+
+        command = "flush_path {file}".format(file=test_new_file)
+        self.asok_command(mds_rank, command, success_validator)
+
+        # check that scrub fails on errors
+        ino = self.mount_a.path_to_ino(new_file)
+        rados_obj_name = "{ino:x}.00000000".format(ino=ino)
+        command = "scrub_path {file}".format(file=test_new_file)
+
+        # Missing parent xattr -> ENODATA
+        self.fs.rados(["rmxattr", rados_obj_name, "parent"], pool=self.fs.get_data_pool_name())
+        self.asok_command(mds_rank, command,
+                          lambda j, r: self.json_validator(j, r, "return_code", -errno.ENODATA))
+
+        # Missing object -> ENOENT
+        self.fs.rados(["rm", rados_obj_name], pool=self.fs.get_data_pool_name())
+        self.asok_command(mds_rank, command,
+                          lambda j, r: self.json_validator(j, r, "return_code", -errno.ENOENT))
+
+        command = "flush_path /"
+        self.asok_command(mds_rank, command, success_validator)
+
+    def test_scrub_repair(self):
+        mds_rank = 0
+        test_dir = "scrub_repair_path"
+
+        self.mount_a.run_shell(["sudo", "mkdir", test_dir])
+        self.mount_a.run_shell(["sudo", "touch", "{0}/file".format(test_dir)])
+        dir_objname = "{:x}.00000000".format(self.mount_a.path_to_ino(test_dir))
+
+        self.mount_a.umount_wait()
+
+        # flush journal entries to dirfrag objects, and expire journal
+        self.fs.mds_asok(['flush', 'journal'])
+        self.fs.mds_stop()
+
+        # remove the dentry from dirfrag, cause incorrect fragstat/rstat
+        self.fs.rados(["rmomapkey", dir_objname, "file_head"],
+                      pool=self.fs.get_metadata_pool_name())
+
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        # fragstat indicates the directory is not empty, rmdir should fail
+        with self.assertRaises(CommandFailedError) as ar:
+            self.mount_a.run_shell(["sudo", "rmdir", test_dir])
+        self.assertEqual(ar.exception.exitstatus, 1)
+
+        self.asok_command(mds_rank, "scrub_path /{0} repair".format(test_dir),
+                          lambda j, r: self.json_validator(j, r, "return_code", 0))
+
+	# wait a few second for background repair
+	time.sleep(10)
+
+	# fragstat should be fixed
+	self.mount_a.run_shell(["sudo", "rmdir", test_dir])
+
+    @staticmethod
+    def json_validator(json_out, rc, element, expected_value):
+        if rc != 0:
+            return False, "asok command returned error {rc}".format(rc=rc)
+        element_value = json_out.get(element)
+        if element_value != expected_value:
+            return False, "unexpectedly got {jv} instead of {ev}!".format(
+                jv=element_value, ev=expected_value)
+        return True, "Succeeded"
+
+    def asok_command(self, mds_rank, command, validator):
+        log.info("Running command '{command}'".format(command=command))
+
+        command_list = command.split()
+
+        # we just assume there's an active mds for every rank
+        mds_id = self.fs.get_active_names()[mds_rank]
+        proc = self.fs.mon_manager.admin_socket('mds', mds_id,
+                                                command_list, check_status=False)
+        rout = proc.exitstatus
+        sout = proc.stdout.getvalue()
+
+        if sout.strip():
+            jout = json.loads(sout)
+        else:
+            jout = None
+
+        log.info("command '{command}' got response code " +
+                 "'{rout}' and stdout '{sout}'".format(
+                     command=command, rout=rout, sout=sout))
+
+        success, errstring = validator(jout, rout)
+
+        if not success:
+            raise AsokCommandFailedError(command, rout, jout, errstring)
+
+        return jout
+
+    def clone_repo(self, client_mount, path):
+        repo = "ceph-qa-suite"
+        repo_path = os.path.join(path, repo)
+        client_mount.run_shell(["mkdir", "-p", path])
+
+        try:
+            client_mount.stat(repo_path)
+        except CommandFailedError:
+            client_mount.run_shell([
+                "git", "clone", '--branch', 'giant',
+                "http://github.com/ceph/{repo}".format(repo=repo),
+                "{path}/{repo}".format(path=path, repo=repo)
+            ])
+
+        return repo_path
+
+
+class AsokCommandFailedError(Exception):
+    """
+    Exception thrown when we get an unexpected response
+    on an admin socket command
+    """
+
+    def __init__(self, command, rc, json_out, errstring):
+        self.command = command
+        self.rc = rc
+        self.json = json_out
+        self.errstring = errstring
+
+    def __str__(self):
+        return "Admin socket: {command} failed with rc={rc}," + \
+               "json output={json}, because '{es}'".format(
+                   command=self.command, rc=self.rc,
+                   json=self.json, es=self.errstring)
diff --git a/src/ceph/qa/tasks/cephfs/test_sessionmap.py b/src/ceph/qa/tasks/cephfs/test_sessionmap.py
new file mode 100644
index 0000000..9d12ab6
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_sessionmap.py
@@ -0,0 +1,235 @@
+from StringIO import StringIO
+import json
+import logging
+from unittest import SkipTest
+
+from tasks.cephfs.fuse_mount import FuseMount
+from teuthology.exceptions import CommandFailedError
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+
+log = logging.getLogger(__name__)
+
+
+class TestSessionMap(CephFSTestCase):
+    CLIENTS_REQUIRED = 2
+    MDSS_REQUIRED = 2
+
+    def test_tell_session_drop(self):
+        """
+        That when a `tell` command is sent using the python CLI,
+        its MDS session is gone after it terminates
+        """
+        self.mount_a.umount_wait()
+        self.mount_b.umount_wait()
+
+        mds_id = self.fs.get_lone_mds_id()
+        self.fs.mon_manager.raw_cluster_cmd("tell", "mds.{0}".format(mds_id), "session", "ls")
+
+        ls_data = self.fs.mds_asok(['session', 'ls'])
+        self.assertEqual(len(ls_data), 0)
+
+    def _get_thread_count(self, mds_id):
+        remote = self.fs.mds_daemons[mds_id].remote
+
+        ps_txt = remote.run(
+            args=["ps", "-ww", "axo", "nlwp,cmd"],
+            stdout=StringIO()
+        ).stdout.getvalue().strip()
+        lines = ps_txt.split("\n")[1:]
+
+        for line in lines:
+            if "ceph-mds" in line and not "daemon-helper" in line:
+                if line.find("-i {0}".format(mds_id)) != -1:
+                    log.info("Found ps line for daemon: {0}".format(line))
+                    return int(line.split()[0])
+
+        raise RuntimeError("No process found in ps output for MDS {0}: {1}".format(
+            mds_id, ps_txt
+        ))
+
+    def test_tell_conn_close(self):
+        """
+        That when a `tell` command is sent using the python CLI,
+        the thread count goes back to where it started (i.e. we aren't
+        leaving connections open)
+        """
+        self.mount_a.umount_wait()
+        self.mount_b.umount_wait()
+
+        mds_id = self.fs.get_lone_mds_id()
+
+        initial_thread_count = self._get_thread_count(mds_id)
+        self.fs.mon_manager.raw_cluster_cmd("tell", "mds.{0}".format(mds_id), "session", "ls")
+        final_thread_count = self._get_thread_count(mds_id)
+
+        self.assertEqual(initial_thread_count, final_thread_count)
+
+    def test_mount_conn_close(self):
+        """
+        That when a client unmounts, the thread count on the MDS goes back
+        to what it was before the client mounted
+        """
+        self.mount_a.umount_wait()
+        self.mount_b.umount_wait()
+
+        mds_id = self.fs.get_lone_mds_id()
+
+        initial_thread_count = self._get_thread_count(mds_id)
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+        self.assertGreater(self._get_thread_count(mds_id), initial_thread_count)
+        self.mount_a.umount_wait()
+        final_thread_count = self._get_thread_count(mds_id)
+
+        self.assertEqual(initial_thread_count, final_thread_count)
+
+    def test_version_splitting(self):
+        """
+        That when many sessions are updated, they are correctly
+        split into multiple versions to obey mds_sessionmap_keys_per_op
+        """
+
+        # Start umounted
+        self.mount_a.umount_wait()
+        self.mount_b.umount_wait()
+
+        # Configure MDS to write one OMAP key at once
+        self.set_conf('mds', 'mds_sessionmap_keys_per_op', 1)
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        # I would like two MDSs, so that I can do an export dir later
+        self.fs.set_max_mds(2)
+        self.fs.wait_for_daemons()
+
+        active_mds_names = self.fs.get_active_names()
+        rank_0_id = active_mds_names[0]
+        rank_1_id = active_mds_names[1]
+        log.info("Ranks 0 and 1 are {0} and {1}".format(
+            rank_0_id, rank_1_id))
+
+        # Bring the clients back
+        self.mount_a.mount()
+        self.mount_b.mount()
+        self.mount_a.create_files()  # Kick the client into opening sessions
+        self.mount_b.create_files()
+
+        # See that they've got sessions
+        self.assert_session_count(2, mds_id=rank_0_id)
+
+        # See that we persist their sessions
+        self.fs.mds_asok(["flush", "journal"], rank_0_id)
+        table_json = json.loads(self.fs.table_tool(["0", "show", "session"]))
+        log.info("SessionMap: {0}".format(json.dumps(table_json, indent=2)))
+        self.assertEqual(table_json['0']['result'], 0)
+        self.assertEqual(len(table_json['0']['data']['Sessions']), 2)
+
+        # Now, induce a "force_open_sessions" event by exporting a dir
+        self.mount_a.run_shell(["mkdir", "bravo"])
+        self.mount_a.run_shell(["touch", "bravo/file"])
+        self.mount_b.run_shell(["ls", "-l", "bravo/file"])
+
+        def get_omap_wrs():
+            return self.fs.mds_asok(['perf', 'dump', 'objecter'], rank_1_id)['objecter']['omap_wr']
+
+        # Flush so that there are no dirty sessions on rank 1
+        self.fs.mds_asok(["flush", "journal"], rank_1_id)
+
+        # Export so that we get a force_open to rank 1 for the two sessions from rank 0
+        initial_omap_wrs = get_omap_wrs()
+        self.fs.mds_asok(['export', 'dir', '/bravo', '1'], rank_0_id)
+
+        # This is the critical (if rather subtle) check: that in the process of doing an export dir,
+        # we hit force_open_sessions, and as a result we end up writing out the sessionmap.  There
+        # will be two sessions dirtied here, and because we have set keys_per_op to 1, we should see
+        # a single session get written out (the first of the two, triggered by the second getting marked
+        # dirty)
+        # The number of writes is two per session, because the header (sessionmap version) update and
+        # KV write both count.
+        self.wait_until_true(
+            lambda: get_omap_wrs() - initial_omap_wrs == 2,
+            timeout=10  # Long enough for an export to get acked
+        )
+
+        # Now end our sessions and check the backing sessionmap is updated correctly
+        self.mount_a.umount_wait()
+        self.mount_b.umount_wait()
+
+        # In-memory sessionmap check
+        self.assert_session_count(0, mds_id=rank_0_id)
+
+        # On-disk sessionmap check
+        self.fs.mds_asok(["flush", "journal"], rank_0_id)
+        table_json = json.loads(self.fs.table_tool(["0", "show", "session"]))
+        log.info("SessionMap: {0}".format(json.dumps(table_json, indent=2)))
+        self.assertEqual(table_json['0']['result'], 0)
+        self.assertEqual(len(table_json['0']['data']['Sessions']), 0)
+
+    def _sudo_write_file(self, remote, path, data):
+        """
+        Write data to a remote file as super user
+
+        :param remote: Remote site.
+        :param path: Path on the remote being written to.
+        :param data: Data to be written.
+
+        Both perms and owner are passed directly to chmod.
+        """
+        remote.run(
+            args=[
+                'sudo',
+                'python',
+                '-c',
+                'import shutil, sys; shutil.copyfileobj(sys.stdin, file(sys.argv[1], "wb"))',
+                path,
+            ],
+            stdin=data,
+        )
+
+    def _configure_auth(self, mount, id_name, mds_caps, osd_caps=None, mon_caps=None):
+        """
+        Set up auth credentials for a client mount, and write out the keyring
+        for the client to use.
+        """
+
+        if osd_caps is None:
+            osd_caps = "allow rw"
+
+        if mon_caps is None:
+            mon_caps = "allow r"
+
+        out = self.fs.mon_manager.raw_cluster_cmd(
+            "auth", "get-or-create", "client.{name}".format(name=id_name),
+            "mds", mds_caps,
+            "osd", osd_caps,
+            "mon", mon_caps
+        )
+        mount.client_id = id_name
+        self._sudo_write_file(mount.client_remote, mount.get_keyring_path(), out)
+        self.set_conf("client.{name}".format(name=id_name), "keyring", mount.get_keyring_path())
+
+    def test_session_reject(self):
+        if not isinstance(self.mount_a, FuseMount):
+            raise SkipTest("Requires FUSE client to inject client metadata")
+
+        self.mount_a.run_shell(["mkdir", "foo"])
+        self.mount_a.run_shell(["mkdir", "foo/bar"])
+        self.mount_a.umount_wait()
+
+        # Mount B will be my rejected client
+        self.mount_b.umount_wait()
+
+        # Configure a client that is limited to /foo/bar
+        self._configure_auth(self.mount_b, "badguy", "allow rw path=/foo/bar")
+        # Check he can mount that dir and do IO
+        self.mount_b.mount(mount_path="/foo/bar")
+        self.mount_b.wait_until_mounted()
+        self.mount_b.create_destroy()
+        self.mount_b.umount_wait()
+
+        # Configure the client to claim that its mount point metadata is /baz
+        self.set_conf("client.badguy", "client_metadata", "root=/baz")
+        # Try to mount the client, see that it fails
+        with self.assert_cluster_log("client session with invalid root '/baz' denied"):
+            with self.assertRaises(CommandFailedError):
+                self.mount_b.mount(mount_path="/foo/bar")
diff --git a/src/ceph/qa/tasks/cephfs/test_strays.py b/src/ceph/qa/tasks/cephfs/test_strays.py
new file mode 100644
index 0000000..b64f3e9
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_strays.py
@@ -0,0 +1,1049 @@
+import json
+import time
+import logging
+from textwrap import dedent
+import datetime
+import gevent
+import datetime
+
+from teuthology.orchestra.run import CommandFailedError, Raw
+from tasks.cephfs.cephfs_test_case import CephFSTestCase, for_teuthology
+
+log = logging.getLogger(__name__)
+
+
+class TestStrays(CephFSTestCase):
+    MDSS_REQUIRED = 2
+
+    OPS_THROTTLE = 1
+    FILES_THROTTLE = 2
+
+    # Range of different file sizes used in throttle test's workload
+    throttle_workload_size_range = 16
+
+    @for_teuthology
+    def test_ops_throttle(self):
+        self._test_throttling(self.OPS_THROTTLE)
+
+    @for_teuthology
+    def test_files_throttle(self):
+        self._test_throttling(self.FILES_THROTTLE)
+
+    def test_dir_deletion(self):
+        """
+        That when deleting a bunch of dentries and the containing
+        directory, everything gets purged.
+        Catches cases where the client might e.g. fail to trim
+        the unlinked dir from its cache.
+        """
+        file_count = 1000
+        create_script = dedent("""
+            import os
+
+            mount_path = "{mount_path}"
+            subdir = "delete_me"
+            size = {size}
+            file_count = {file_count}
+            os.mkdir(os.path.join(mount_path, subdir))
+            for i in xrange(0, file_count):
+                filename = "{{0}}_{{1}}.bin".format(i, size)
+                f = open(os.path.join(mount_path, subdir, filename), 'w')
+                f.write(size * 'x')
+                f.close()
+        """.format(
+            mount_path=self.mount_a.mountpoint,
+            size=1024,
+            file_count=file_count
+        ))
+
+        self.mount_a.run_python(create_script)
+
+        # That the dirfrag object is created
+        self.fs.mds_asok(["flush", "journal"])
+        dir_ino = self.mount_a.path_to_ino("delete_me")
+        self.assertTrue(self.fs.dirfrag_exists(dir_ino, 0))
+
+        # Remove everything
+        self.mount_a.run_shell(["rm", "-rf", "delete_me"])
+        self.fs.mds_asok(["flush", "journal"])
+
+        # That all the removed files get created as strays
+        strays = self.get_mdc_stat("strays_created")
+        self.assertEqual(strays, file_count + 1)
+
+        # That the strays all get enqueued for purge
+        self.wait_until_equal(
+            lambda: self.get_mdc_stat("strays_enqueued"),
+            strays,
+            timeout=600
+
+        )
+
+        # That all the purge operations execute
+        self.wait_until_equal(
+            lambda: self.get_stat("purge_queue", "pq_executed"),
+            strays,
+            timeout=600
+        )
+
+        # That finally, the directory metadata object is gone
+        self.assertFalse(self.fs.dirfrag_exists(dir_ino, 0))
+
+        # That finally, the data objects are all gone
+        self.await_data_pool_empty()
+
+    def _test_throttling(self, throttle_type):
+        self.data_log = []
+        try:
+            return self._do_test_throttling(throttle_type)
+        except:
+            for l in self.data_log:
+                log.info(",".join([l_.__str__() for l_ in l]))
+            raise
+
+    def _do_test_throttling(self, throttle_type):
+        """
+        That the mds_max_purge_ops setting is respected
+        """
+
+        def set_throttles(files, ops):
+            """
+            Helper for updating ops/files limits, and calculating effective
+            ops_per_pg setting to give the same ops limit.
+            """
+            self.set_conf('mds', 'mds_max_purge_files', "%d" % files)
+            self.set_conf('mds', 'mds_max_purge_ops', "%d" % ops)
+
+            pgs = self.fs.mon_manager.get_pool_property(
+                self.fs.get_data_pool_name(),
+                "pg_num"
+            )
+            ops_per_pg = float(ops) / pgs
+            self.set_conf('mds', 'mds_max_purge_ops_per_pg', "%s" % ops_per_pg)
+
+        # Test conditions depend on what we're going to be exercising.
+        # * Lift the threshold on whatever throttle we are *not* testing, so
+        #   that the throttle of interest is the one that will be the bottleneck
+        # * Create either many small files (test file count throttling) or fewer
+        #   large files (test op throttling)
+        if throttle_type == self.OPS_THROTTLE:
+            set_throttles(files=100000000, ops=16)
+            size_unit = 1024 * 1024  # big files, generate lots of ops
+            file_multiplier = 100
+        elif throttle_type == self.FILES_THROTTLE:
+            # The default value of file limit is pretty permissive, so to avoid
+            # the test running too fast, create lots of files and set the limit
+            # pretty low.
+            set_throttles(ops=100000000, files=6)
+            size_unit = 1024  # small, numerous files
+            file_multiplier = 200
+        else:
+            raise NotImplemented(throttle_type)
+
+        # Pick up config changes
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        create_script = dedent("""
+            import os
+
+            mount_path = "{mount_path}"
+            subdir = "delete_me"
+            size_unit = {size_unit}
+            file_multiplier = {file_multiplier}
+            os.mkdir(os.path.join(mount_path, subdir))
+            for i in xrange(0, file_multiplier):
+                for size in xrange(0, {size_range}*size_unit, size_unit):
+                    filename = "{{0}}_{{1}}.bin".format(i, size / size_unit)
+                    f = open(os.path.join(mount_path, subdir, filename), 'w')
+                    f.write(size * 'x')
+                    f.close()
+        """.format(
+            mount_path=self.mount_a.mountpoint,
+            size_unit=size_unit,
+            file_multiplier=file_multiplier,
+            size_range=self.throttle_workload_size_range
+        ))
+
+        self.mount_a.run_python(create_script)
+
+        # We will run the deletion in the background, to reduce the risk of it completing before
+        # we have started monitoring the stray statistics.
+        def background():
+            self.mount_a.run_shell(["rm", "-rf", "delete_me"])
+            self.fs.mds_asok(["flush", "journal"])
+
+        background_thread = gevent.spawn(background)
+
+        total_inodes = file_multiplier * self.throttle_workload_size_range + 1
+        mds_max_purge_ops = int(self.fs.get_config("mds_max_purge_ops", 'mds'))
+        mds_max_purge_files = int(self.fs.get_config("mds_max_purge_files", 'mds'))
+
+        # During this phase we look for the concurrent ops to exceed half
+        # the limit (a heuristic) and not exceed the limit (a correctness
+        # condition).
+        purge_timeout = 600
+        elapsed = 0
+        files_high_water = 0
+        ops_high_water = 0
+
+        while True:
+            stats = self.fs.mds_asok(['perf', 'dump'])
+            mdc_stats = stats['mds_cache']
+            pq_stats = stats['purge_queue']
+            if elapsed >= purge_timeout:
+                raise RuntimeError("Timeout waiting for {0} inodes to purge, stats:{1}".format(total_inodes, mdc_stats))
+
+            num_strays = mdc_stats['num_strays']
+            num_strays_purging = pq_stats['pq_executing']
+            num_purge_ops = pq_stats['pq_executing_ops']
+
+            self.data_log.append([datetime.datetime.now(), num_strays, num_strays_purging, num_purge_ops])
+
+            files_high_water = max(files_high_water, num_strays_purging)
+            ops_high_water = max(ops_high_water, num_purge_ops)
+
+            total_strays_created = mdc_stats['strays_created']
+            total_strays_purged = pq_stats['pq_executed']
+
+            if total_strays_purged == total_inodes:
+                log.info("Complete purge in {0} seconds".format(elapsed))
+                break
+            elif total_strays_purged > total_inodes:
+                raise RuntimeError("Saw more strays than expected, mdc stats: {0}".format(mdc_stats))
+            else:
+                if throttle_type == self.OPS_THROTTLE:
+                    # 11 is filer_max_purge_ops plus one for the backtrace:
+                    # limit is allowed to be overshot by this much.
+                    if num_purge_ops > mds_max_purge_ops + 11:
+                        raise RuntimeError("num_purge_ops violates threshold {0}/{1}".format(
+                            num_purge_ops, mds_max_purge_ops
+                        ))
+                elif throttle_type == self.FILES_THROTTLE:
+                    if num_strays_purging > mds_max_purge_files:
+                        raise RuntimeError("num_strays_purging violates threshold {0}/{1}".format(
+                            num_strays_purging, mds_max_purge_files
+                        ))
+                else:
+                    raise NotImplemented(throttle_type)
+
+                log.info("Waiting for purge to complete {0}/{1}, {2}/{3}".format(
+                    num_strays_purging, num_strays,
+                    total_strays_purged, total_strays_created
+                ))
+                time.sleep(1)
+                elapsed += 1
+
+        background_thread.join()
+
+        # Check that we got up to a respectable rate during the purge.  This is totally
+        # racy, but should be safeish unless the cluster is pathologically slow, or
+        # insanely fast such that the deletions all pass before we have polled the
+        # statistics.
+        if throttle_type == self.OPS_THROTTLE:
+            if ops_high_water < mds_max_purge_ops / 2:
+                raise RuntimeError("Ops in flight high water is unexpectedly low ({0} / {1})".format(
+                    ops_high_water, mds_max_purge_ops
+                ))
+        elif throttle_type == self.FILES_THROTTLE:
+            if files_high_water < mds_max_purge_files / 2:
+                raise RuntimeError("Files in flight high water is unexpectedly low ({0} / {1})".format(
+                    ops_high_water, mds_max_purge_files
+                ))
+
+        # Sanity check all MDC stray stats
+        stats = self.fs.mds_asok(['perf', 'dump'])
+        mdc_stats = stats['mds_cache']
+        pq_stats = stats['purge_queue']
+        self.assertEqual(mdc_stats['num_strays'], 0)
+        self.assertEqual(mdc_stats['num_strays_delayed'], 0)
+        self.assertEqual(pq_stats['pq_executing'], 0)
+        self.assertEqual(pq_stats['pq_executing_ops'], 0)
+        self.assertEqual(mdc_stats['strays_created'], total_inodes)
+        self.assertEqual(mdc_stats['strays_enqueued'], total_inodes)
+        self.assertEqual(pq_stats['pq_executed'], total_inodes)
+
+    def get_mdc_stat(self, name, mds_id=None):
+        return self.get_stat("mds_cache", name, mds_id)
+
+    def get_stat(self, subsys, name, mds_id=None):
+        return self.fs.mds_asok(['perf', 'dump', subsys, name],
+                                mds_id=mds_id)[subsys][name]
+
+    def _wait_for_counter(self, subsys, counter, expect_val, timeout=60,
+                          mds_id=None):
+        self.wait_until_equal(
+            lambda: self.get_stat(subsys, counter, mds_id),
+            expect_val=expect_val, timeout=timeout,
+            reject_fn=lambda x: x > expect_val
+        )
+
+    def test_open_inode(self):
+        """
+        That the case of a dentry unlinked while a client holds an
+        inode open is handled correctly.
+
+        The inode should be moved into a stray dentry, while the original
+        dentry and directory should be purged.
+
+        The inode's data should be purged when the client eventually closes
+        it.
+        """
+        mount_a_client_id = self.mount_a.get_global_id()
+
+        # Write some bytes to a file
+        size_mb = 8
+
+        # Hold the file open
+        p = self.mount_a.open_background("open_file")
+        self.mount_a.write_n_mb("open_file", size_mb)
+        open_file_ino = self.mount_a.path_to_ino("open_file")
+
+        self.assertEqual(self.get_session(mount_a_client_id)['num_caps'], 2)
+
+        # Unlink the dentry
+        self.mount_a.run_shell(["rm", "-f", "open_file"])
+
+        # Wait to see the stray count increment
+        self.wait_until_equal(
+            lambda: self.get_mdc_stat("num_strays"),
+            expect_val=1, timeout=60, reject_fn=lambda x: x > 1)
+
+        # See that while the stray count has incremented, none have passed
+        # on to the purge queue
+        self.assertEqual(self.get_mdc_stat("strays_created"), 1)
+        self.assertEqual(self.get_mdc_stat("strays_enqueued"), 0)
+
+        # See that the client still holds 2 caps
+        self.assertEqual(self.get_session(mount_a_client_id)['num_caps'], 2)
+
+        # See that the data objects remain in the data pool
+        self.assertTrue(self.fs.data_objects_present(open_file_ino, size_mb * 1024 * 1024))
+
+        # Now close the file
+        self.mount_a.kill_background(p)
+
+        # Wait to see the client cap count decrement
+        self.wait_until_equal(
+            lambda: self.get_session(mount_a_client_id)['num_caps'],
+            expect_val=1, timeout=60, reject_fn=lambda x: x > 2 or x < 1
+        )
+        # Wait to see the purge counter increment, stray count go to zero
+        self._wait_for_counter("mds_cache", "strays_enqueued", 1)
+        self.wait_until_equal(
+            lambda: self.get_mdc_stat("num_strays"),
+            expect_val=0, timeout=6, reject_fn=lambda x: x > 1
+        )
+        self._wait_for_counter("purge_queue", "pq_executed", 1)
+
+        # See that the data objects no longer exist
+        self.assertTrue(self.fs.data_objects_absent(open_file_ino, size_mb * 1024 * 1024))
+
+        self.await_data_pool_empty()
+
+    def test_hardlink_reintegration(self):
+        """
+        That removal of primary dentry of hardlinked inode results
+        in reintegration of inode into the previously-remote dentry,
+        rather than lingering as a stray indefinitely.
+        """
+        # Write some bytes to file_a
+        size_mb = 8
+        self.mount_a.run_shell(["mkdir", "dir_1"])
+        self.mount_a.write_n_mb("dir_1/file_a", size_mb)
+        ino = self.mount_a.path_to_ino("dir_1/file_a")
+
+        # Create a hardlink named file_b
+        self.mount_a.run_shell(["mkdir", "dir_2"])
+        self.mount_a.run_shell(["ln", "dir_1/file_a", "dir_2/file_b"])
+        self.assertEqual(self.mount_a.path_to_ino("dir_2/file_b"), ino)
+
+        # Flush journal
+        self.fs.mds_asok(['flush', 'journal'])
+
+        # See that backtrace for the file points to the file_a path
+        pre_unlink_bt = self.fs.read_backtrace(ino)
+        self.assertEqual(pre_unlink_bt['ancestors'][0]['dname'], "file_a")
+
+        # empty mds cache. otherwise mds reintegrates stray when unlink finishes
+        self.mount_a.umount_wait()
+        self.fs.mds_asok(['flush', 'journal'])
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+        self.mount_a.mount()
+
+        # Unlink file_a
+        self.mount_a.run_shell(["rm", "-f", "dir_1/file_a"])
+
+        # See that a stray was created
+        self.assertEqual(self.get_mdc_stat("num_strays"), 1)
+        self.assertEqual(self.get_mdc_stat("strays_created"), 1)
+
+        # Wait, see that data objects are still present (i.e. that the
+        # stray did not advance to purging given time)
+        time.sleep(30)
+        self.assertTrue(self.fs.data_objects_present(ino, size_mb * 1024 * 1024))
+        self.assertEqual(self.get_mdc_stat("strays_enqueued"), 0)
+
+        # See that before reintegration, the inode's backtrace points to a stray dir
+        self.fs.mds_asok(['flush', 'journal'])
+        self.assertTrue(self.get_backtrace_path(ino).startswith("stray"))
+
+        last_reintegrated = self.get_mdc_stat("strays_reintegrated")
+
+        # Do a metadata operation on the remaining link (mv is heavy handed, but
+        # others like touch may be satisfied from caps without poking MDS)
+        self.mount_a.run_shell(["mv", "dir_2/file_b", "dir_2/file_c"])
+
+        # Stray reintegration should happen as a result of the eval_remote call
+        # on responding to a client request.
+        self.wait_until_equal(
+            lambda: self.get_mdc_stat("num_strays"),
+            expect_val=0,
+            timeout=60
+        )
+
+        # See the reintegration counter increment
+        curr_reintegrated = self.get_mdc_stat("strays_reintegrated")
+        self.assertGreater(curr_reintegrated, last_reintegrated)
+        last_reintegrated = curr_reintegrated
+
+        # Flush the journal
+        self.fs.mds_asok(['flush', 'journal'])
+
+        # See that the backtrace for the file points to the remaining link's path
+        post_reint_bt = self.fs.read_backtrace(ino)
+        self.assertEqual(post_reint_bt['ancestors'][0]['dname'], "file_c")
+
+        # mds should reintegrates stray when unlink finishes
+        self.mount_a.run_shell(["ln", "dir_2/file_c", "dir_2/file_d"])
+        self.mount_a.run_shell(["rm", "-f", "dir_2/file_c"])
+
+        # Stray reintegration should happen as a result of the notify_stray call
+        # on completion of unlink
+        self.wait_until_equal(
+            lambda: self.get_mdc_stat("num_strays"),
+            expect_val=0,
+            timeout=60
+        )
+
+        # See the reintegration counter increment
+        curr_reintegrated = self.get_mdc_stat("strays_reintegrated")
+        self.assertGreater(curr_reintegrated, last_reintegrated)
+        last_reintegrated = curr_reintegrated
+
+        # Flush the journal
+        self.fs.mds_asok(['flush', 'journal'])
+
+        # See that the backtrace for the file points to the newest link's path
+        post_reint_bt = self.fs.read_backtrace(ino)
+        self.assertEqual(post_reint_bt['ancestors'][0]['dname'], "file_d")
+
+        # Now really delete it
+        self.mount_a.run_shell(["rm", "-f", "dir_2/file_d"])
+        self._wait_for_counter("mds_cache", "strays_enqueued", 1)
+        self._wait_for_counter("purge_queue", "pq_executed", 1)
+
+        self.assert_purge_idle()
+        self.assertTrue(self.fs.data_objects_absent(ino, size_mb * 1024 * 1024))
+
+        # We caused the inode to go stray 3 times
+        self.assertEqual(self.get_mdc_stat("strays_created"), 3)
+        # We purged it at the last
+        self.assertEqual(self.get_mdc_stat("strays_enqueued"), 1)
+
+    def test_mv_hardlink_cleanup(self):
+        """
+        That when doing a rename from A to B, and B has hardlinks,
+        then we make a stray for B which is then reintegrated
+        into one of his hardlinks.
+        """
+        # Create file_a, file_b, and a hardlink to file_b
+        size_mb = 8
+        self.mount_a.write_n_mb("file_a", size_mb)
+        file_a_ino = self.mount_a.path_to_ino("file_a")
+
+        self.mount_a.write_n_mb("file_b", size_mb)
+        file_b_ino = self.mount_a.path_to_ino("file_b")
+
+        self.mount_a.run_shell(["ln", "file_b", "linkto_b"])
+        self.assertEqual(self.mount_a.path_to_ino("linkto_b"), file_b_ino)
+
+        # mv file_a file_b
+        self.mount_a.run_shell(["mv", "file_a", "file_b"])
+
+        # Stray reintegration should happen as a result of the notify_stray call on
+        # completion of rename
+        self.wait_until_equal(
+            lambda: self.get_mdc_stat("num_strays"),
+            expect_val=0,
+            timeout=60
+        )
+
+        self.assertEqual(self.get_mdc_stat("strays_created"), 1)
+        self.assertGreaterEqual(self.get_mdc_stat("strays_reintegrated"), 1)
+
+        # No data objects should have been deleted, as both files still have linkage.
+        self.assertTrue(self.fs.data_objects_present(file_a_ino, size_mb * 1024 * 1024))
+        self.assertTrue(self.fs.data_objects_present(file_b_ino, size_mb * 1024 * 1024))
+
+        self.fs.mds_asok(['flush', 'journal'])
+
+        post_reint_bt = self.fs.read_backtrace(file_b_ino)
+        self.assertEqual(post_reint_bt['ancestors'][0]['dname'], "linkto_b")
+
+    def _setup_two_ranks(self):
+        # Set up two MDSs
+        self.fs.set_max_mds(2)
+
+        # See that we have two active MDSs
+        self.wait_until_equal(lambda: len(self.fs.get_active_names()), 2, 30,
+                              reject_fn=lambda v: v > 2 or v < 1)
+
+        active_mds_names = self.fs.get_active_names()
+        rank_0_id = active_mds_names[0]
+        rank_1_id = active_mds_names[1]
+        log.info("Ranks 0 and 1 are {0} and {1}".format(
+            rank_0_id, rank_1_id))
+
+        # Get rid of other MDS daemons so that it's easier to know which
+        # daemons to expect in which ranks after restarts
+        for unneeded_mds in set(self.mds_cluster.mds_ids) - {rank_0_id, rank_1_id}:
+            self.mds_cluster.mds_stop(unneeded_mds)
+            self.mds_cluster.mds_fail(unneeded_mds)
+
+        return rank_0_id, rank_1_id
+
+    def _force_migrate(self, to_id, path, watch_ino):
+        """
+        :param to_id: MDS id to move it to
+        :param path: Filesystem path (string) to move
+        :param watch_ino: Inode number to look for at destination to confirm move
+        :return: None
+        """
+        self.mount_a.run_shell(["setfattr", "-n", "ceph.dir.pin", "-v", "1", path])
+
+        # Poll the MDS cache dump to watch for the export completing
+        migrated = False
+        migrate_timeout = 60
+        migrate_elapsed = 0
+        while not migrated:
+            data = self.fs.mds_asok(["dump", "cache"], to_id)
+            for inode_data in data:
+                if inode_data['ino'] == watch_ino:
+                    log.debug("Found ino in cache: {0}".format(json.dumps(inode_data, indent=2)))
+                    if inode_data['is_auth'] is True:
+                        migrated = True
+                    break
+
+            if not migrated:
+                if migrate_elapsed > migrate_timeout:
+                    raise RuntimeError("Migration hasn't happened after {0}s!".format(migrate_elapsed))
+                else:
+                    migrate_elapsed += 1
+                    time.sleep(1)
+
+    def _is_stopped(self, rank):
+        mds_map = self.fs.get_mds_map()
+        return rank not in [i['rank'] for i in mds_map['info'].values()]
+
+    def test_purge_on_shutdown(self):
+        """
+        That when an MDS rank is shut down, its purge queue is
+        drained in the process.
+        """
+        rank_0_id, rank_1_id = self._setup_two_ranks()
+
+        self.set_conf("mds.{0}".format(rank_1_id), 'mds_max_purge_files', "0")
+        self.mds_cluster.mds_fail_restart(rank_1_id)
+        self.fs.wait_for_daemons()
+
+        file_count = 5
+
+        self.mount_a.create_n_files("delete_me/file", file_count)
+
+        self._force_migrate(rank_1_id, "delete_me",
+                            self.mount_a.path_to_ino("delete_me/file_0"))
+
+        self.mount_a.run_shell(["rm", "-rf", Raw("delete_me/*")])
+        self.mount_a.umount_wait()
+
+        # See all the strays go into purge queue
+        self._wait_for_counter("mds_cache", "strays_created", file_count, mds_id=rank_1_id)
+        self._wait_for_counter("mds_cache", "strays_enqueued", file_count, mds_id=rank_1_id)
+        self.assertEqual(self.get_stat("mds_cache", "num_strays", mds_id=rank_1_id), 0)
+
+        # See nothing get purged from the purge queue (yet)
+        time.sleep(10)
+        self.assertEqual(self.get_stat("purge_queue", "pq_executed", mds_id=rank_1_id), 0)
+
+        # Shut down rank 1
+        self.fs.set_max_mds(1)
+        self.fs.deactivate(1)
+
+        # It shouldn't proceed past stopping because its still not allowed
+        # to purge
+        time.sleep(10)
+        self.assertEqual(self.get_stat("purge_queue", "pq_executed", mds_id=rank_1_id), 0)
+        self.assertFalse(self._is_stopped(1))
+
+        # Permit the daemon to start purging again
+        self.fs.mon_manager.raw_cluster_cmd('tell', 'mds.{0}'.format(rank_1_id),
+                                            'injectargs',
+                                            "--mds_max_purge_files 100")
+
+        # It should now proceed through shutdown
+        self.wait_until_true(
+            lambda: self._is_stopped(1),
+            timeout=60
+        )
+
+        # ...and in the process purge all that data
+        self.await_data_pool_empty()
+
+    def test_migration_on_shutdown(self):
+        """
+        That when an MDS rank is shut down, any non-purgeable strays
+        get migrated to another rank.
+        """
+
+        rank_0_id, rank_1_id = self._setup_two_ranks()
+
+        # Create a non-purgeable stray in a ~mds1 stray directory
+        # by doing a hard link and deleting the original file
+        self.mount_a.run_shell(["mkdir", "dir_1", "dir_2"])
+        self.mount_a.run_shell(["touch", "dir_1/original"])
+        self.mount_a.run_shell(["ln", "dir_1/original", "dir_2/linkto"])
+
+        self._force_migrate(rank_1_id, "dir_1",
+                            self.mount_a.path_to_ino("dir_1/original"))
+
+        # empty mds cache. otherwise mds reintegrates stray when unlink finishes
+        self.mount_a.umount_wait()
+        self.fs.mds_asok(['flush', 'journal'], rank_0_id)
+        self.fs.mds_asok(['flush', 'journal'], rank_1_id)
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        active_mds_names = self.fs.get_active_names()
+        rank_0_id = active_mds_names[0]
+        rank_1_id = active_mds_names[1]
+
+        self.mount_a.mount()
+
+        self.mount_a.run_shell(["rm", "-f", "dir_1/original"])
+        self.mount_a.umount_wait()
+
+        self._wait_for_counter("mds_cache", "strays_created", 1,
+                               mds_id=rank_1_id)
+
+        # Shut down rank 1
+        self.fs.mon_manager.raw_cluster_cmd_result('mds', 'set', "max_mds", "1")
+        self.fs.mon_manager.raw_cluster_cmd_result('mds', 'deactivate', "1")
+
+        # Wait til we get to a single active MDS mdsmap state
+        self.wait_until_true(lambda: self._is_stopped(1), timeout=120)
+
+        # See that the stray counter on rank 0 has incremented
+        self.assertEqual(self.get_mdc_stat("strays_created", rank_0_id), 1)
+
+    def assert_backtrace(self, ino, expected_path):
+        """
+        Assert that the backtrace in the data pool for an inode matches
+        an expected /foo/bar path.
+        """
+        expected_elements = expected_path.strip("/").split("/")
+        bt = self.fs.read_backtrace(ino)
+        actual_elements = list(reversed([dn['dname'] for dn in bt['ancestors']]))
+        self.assertListEqual(expected_elements, actual_elements)
+
+    def get_backtrace_path(self, ino):
+        bt = self.fs.read_backtrace(ino)
+        elements = reversed([dn['dname'] for dn in bt['ancestors']])
+        return "/".join(elements)
+
+    def assert_purge_idle(self):
+        """
+        Assert that the MDS perf counters indicate no strays exist and
+        no ongoing purge activity.  Sanity check for when PurgeQueue should
+        be idle.
+        """
+        mdc_stats = self.fs.mds_asok(['perf', 'dump', "mds_cache"])['mds_cache']
+        pq_stats = self.fs.mds_asok(['perf', 'dump', "purge_queue"])['purge_queue']
+        self.assertEqual(mdc_stats["num_strays"], 0)
+        self.assertEqual(mdc_stats["num_strays_delayed"], 0)
+        self.assertEqual(pq_stats["pq_executing"], 0)
+        self.assertEqual(pq_stats["pq_executing_ops"], 0)
+
+    def test_mv_cleanup(self):
+        """
+        That when doing a rename from A to B, and B has no hardlinks,
+        then we make a stray for B and purge him.
+        """
+        # Create file_a and file_b, write some to both
+        size_mb = 8
+        self.mount_a.write_n_mb("file_a", size_mb)
+        file_a_ino = self.mount_a.path_to_ino("file_a")
+        self.mount_a.write_n_mb("file_b", size_mb)
+        file_b_ino = self.mount_a.path_to_ino("file_b")
+
+        self.fs.mds_asok(['flush', 'journal'])
+        self.assert_backtrace(file_a_ino, "file_a")
+        self.assert_backtrace(file_b_ino, "file_b")
+
+        # mv file_a file_b
+        self.mount_a.run_shell(['mv', 'file_a', 'file_b'])
+
+        # See that stray counter increments
+        self.assertEqual(self.get_mdc_stat("strays_created"), 1)
+        # Wait for purge counter to increment
+        self._wait_for_counter("mds_cache", "strays_enqueued", 1)
+        self._wait_for_counter("purge_queue", "pq_executed", 1)
+
+        self.assert_purge_idle()
+
+        # file_b should have been purged
+        self.assertTrue(self.fs.data_objects_absent(file_b_ino, size_mb * 1024 * 1024))
+
+        # Backtrace should have updated from file_a to file_b
+        self.fs.mds_asok(['flush', 'journal'])
+        self.assert_backtrace(file_a_ino, "file_b")
+
+        # file_a's data should still exist
+        self.assertTrue(self.fs.data_objects_present(file_a_ino, size_mb * 1024 * 1024))
+
+    def _pool_df(self, pool_name):
+        """
+        Return a dict like
+            {
+                "kb_used": 0,
+                "bytes_used": 0,
+                "max_avail": 19630292406,
+                "objects": 0
+            }
+
+        :param pool_name: Which pool (must exist)
+        """
+        out = self.fs.mon_manager.raw_cluster_cmd("df", "--format=json-pretty")
+        for p in json.loads(out)['pools']:
+            if p['name'] == pool_name:
+                return p['stats']
+
+        raise RuntimeError("Pool '{0}' not found".format(pool_name))
+
+    def await_data_pool_empty(self):
+        self.wait_until_true(
+            lambda: self._pool_df(
+                self.fs.get_data_pool_name()
+            )['objects'] == 0,
+            timeout=60)
+
+    def test_snapshot_remove(self):
+        """
+        That removal of a snapshot that references a now-unlinked file results
+        in purging on the stray for the file.
+        """
+        # Enable snapshots
+        self.fs.mon_manager.raw_cluster_cmd("mds", "set", "allow_new_snaps", "true",
+                                            "--yes-i-really-mean-it")
+
+        # Create a dir with a file in it
+        size_mb = 8
+        self.mount_a.run_shell(["mkdir", "snapdir"])
+        self.mount_a.run_shell(["mkdir", "snapdir/subdir"])
+        self.mount_a.write_test_pattern("snapdir/subdir/file_a", size_mb * 1024 * 1024)
+        file_a_ino = self.mount_a.path_to_ino("snapdir/subdir/file_a")
+
+        # Snapshot the dir
+        self.mount_a.run_shell(["mkdir", "snapdir/.snap/snap1"])
+
+        # Cause the head revision to deviate from the snapshot
+        self.mount_a.write_n_mb("snapdir/subdir/file_a", size_mb)
+
+        # Flush the journal so that backtraces, dirfrag objects will actually be written
+        self.fs.mds_asok(["flush", "journal"])
+
+        # Unlink the file
+        self.mount_a.run_shell(["rm", "-f", "snapdir/subdir/file_a"])
+        self.mount_a.run_shell(["rmdir", "snapdir/subdir"])
+
+        # Unmount the client because when I come back to check the data is still
+        # in the file I don't want to just see what's in the page cache.
+        self.mount_a.umount_wait()
+
+        self.assertEqual(self.get_mdc_stat("strays_created"), 2)
+
+        # FIXME: at this stage we see a purge and the stray count drops to
+        # zero, but there's actually still a stray, so at the very
+        # least the StrayManager stats code is slightly off
+
+        self.mount_a.mount()
+
+        # See that the data from the snapshotted revision of the file is still present
+        # and correct
+        self.mount_a.validate_test_pattern("snapdir/.snap/snap1/subdir/file_a", size_mb * 1024 * 1024)
+
+        # Remove the snapshot
+        self.mount_a.run_shell(["rmdir", "snapdir/.snap/snap1"])
+
+        # Purging file_a doesn't happen until after we've flushed the journal, because
+        # it is referenced by the snapshotted subdir, and the snapshot isn't really
+        # gone until the journal references to it are gone
+        self.fs.mds_asok(["flush", "journal"])
+
+        # Wait for purging to complete, which requires the OSDMap to propagate to the OSDs.
+        # See also: http://tracker.ceph.com/issues/20072
+        self.wait_until_true(
+            lambda: self.fs.data_objects_absent(file_a_ino, size_mb * 1024 * 1024),
+            timeout=60
+        )
+
+        # See that a purge happens now
+        self._wait_for_counter("mds_cache", "strays_enqueued", 2)
+        self._wait_for_counter("purge_queue", "pq_executed", 2)
+
+        self.await_data_pool_empty()
+
+    def test_fancy_layout(self):
+        """
+        purge stray file with fancy layout
+        """
+
+        file_name = "fancy_layout_file"
+        self.mount_a.run_shell(["touch", file_name])
+
+        file_layout = "stripe_unit=1048576 stripe_count=4 object_size=8388608"
+        self.mount_a.setfattr(file_name, "ceph.file.layout", file_layout)
+
+        # 35MB requires 7 objects
+        size_mb = 35
+        self.mount_a.write_n_mb(file_name, size_mb)
+
+        self.mount_a.run_shell(["rm", "-f", file_name])
+        self.fs.mds_asok(["flush", "journal"])
+
+        # can't use self.fs.data_objects_absent here, it does not support fancy layout
+        self.await_data_pool_empty()
+
+    def test_dirfrag_limit(self):
+        """
+        That the directory fragment size cannot exceed mds_bal_fragment_size_max (using a limit of 50 in all configurations).
+
+        That fragmentation (forced) will allow more entries to be created.
+
+        That unlinking fails when the stray directory fragment becomes too large and that unlinking may continue once those strays are purged.
+        """
+
+        self.fs.set_allow_dirfrags(True)
+
+        LOW_LIMIT = 50
+        for mds in self.fs.get_daemon_names():
+            self.fs.mds_asok(["config", "set", "mds_bal_fragment_size_max", str(LOW_LIMIT)], mds)
+
+        try:
+            self.mount_a.run_python(dedent("""
+                import os
+                path = os.path.join("{path}", "subdir")
+                os.mkdir(path)
+                for n in range(0, {file_count}):
+                    open(os.path.join(path, "%s" % n), 'w').write("%s" % n)
+                """.format(
+            path=self.mount_a.mountpoint,
+            file_count=LOW_LIMIT+1
+            )))
+        except CommandFailedError:
+            pass # ENOSPAC
+        else:
+            raise RuntimeError("fragment size exceeded")
+
+        # Now test that we can go beyond the limit if we fragment the directory
+
+        self.mount_a.run_python(dedent("""
+            import os
+            path = os.path.join("{path}", "subdir2")
+            os.mkdir(path)
+            for n in range(0, {file_count}):
+                open(os.path.join(path, "%s" % n), 'w').write("%s" % n)
+            dfd = os.open(path, os.O_DIRECTORY)
+            os.fsync(dfd)
+            """.format(
+        path=self.mount_a.mountpoint,
+        file_count=LOW_LIMIT
+        )))
+
+        # Ensure that subdir2 is fragmented
+        mds_id = self.fs.get_active_names()[0]
+        self.fs.mds_asok(["dirfrag", "split", "/subdir2", "0/0", "1"], mds_id)
+
+        # remount+flush (release client caps)
+        self.mount_a.umount_wait()
+        self.fs.mds_asok(["flush", "journal"], mds_id)
+        self.mount_a.mount()
+        self.mount_a.wait_until_mounted()
+
+        # Create 50% more files than the current fragment limit
+        self.mount_a.run_python(dedent("""
+            import os
+            path = os.path.join("{path}", "subdir2")
+            for n in range({file_count}, ({file_count}*3)//2):
+                open(os.path.join(path, "%s" % n), 'w').write("%s" % n)
+            """.format(
+        path=self.mount_a.mountpoint,
+        file_count=LOW_LIMIT
+        )))
+
+        # Now test the stray directory size is limited and recovers
+        strays_before = self.get_mdc_stat("strays_created")
+        try:
+            self.mount_a.run_python(dedent("""
+                import os
+                path = os.path.join("{path}", "subdir3")
+                os.mkdir(path)
+                for n in range({file_count}):
+                    fpath = os.path.join(path, "%s" % n)
+                    f = open(fpath, 'w')
+                    f.write("%s" % n)
+                    f.close()
+                    os.unlink(fpath)
+                """.format(
+            path=self.mount_a.mountpoint,
+            file_count=LOW_LIMIT*10 # 10 stray directories, should collide before this count
+            )))
+        except CommandFailedError:
+            pass # ENOSPAC
+        else:
+            raise RuntimeError("fragment size exceeded")
+
+        strays_after = self.get_mdc_stat("strays_created")
+        self.assertGreaterEqual(strays_after-strays_before, LOW_LIMIT)
+
+        self._wait_for_counter("mds_cache", "strays_enqueued", strays_after)
+        self._wait_for_counter("purge_queue", "pq_executed", strays_after)
+
+        self.mount_a.run_python(dedent("""
+            import os
+            path = os.path.join("{path}", "subdir4")
+            os.mkdir(path)
+            for n in range({file_count}):
+                fpath = os.path.join(path, "%s" % n)
+                f = open(fpath, 'w')
+                f.write("%s" % n)
+                f.close()
+                os.unlink(fpath)
+            """.format(
+        path=self.mount_a.mountpoint,
+        file_count=LOW_LIMIT
+        )))
+
+    def test_purge_queue_upgrade(self):
+        """
+        That when starting on a system with no purge queue in the metadata
+        pool, we silently create one.
+        :return:
+        """
+
+        self.mds_cluster.mds_stop()
+        self.mds_cluster.mds_fail()
+        self.fs.rados(["rm", "500.00000000"])
+        self.mds_cluster.mds_restart()
+        self.fs.wait_for_daemons()
+
+    def test_purge_queue_op_rate(self):
+        """
+        A busy purge queue is meant to aggregate operations sufficiently
+        that our RADOS ops to the metadata pool are not O(files).  Check
+        that that is so.
+        :return:
+        """
+
+        # For low rates of deletion, the rate of metadata ops actually
+        # will be o(files), so to see the desired behaviour we have to give
+        # the system a significant quantity, i.e. an order of magnitude
+        # more than the number of files it will purge at one time.
+
+        max_purge_files = 2
+
+        self.set_conf('mds', 'mds_bal_frag', 'false')
+        self.set_conf('mds', 'mds_max_purge_files', "%d" % max_purge_files)
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        phase_1_files = 256
+        phase_2_files = 512
+
+        self.mount_a.run_shell(["mkdir", "phase1"])
+        self.mount_a.create_n_files("phase1/file", phase_1_files)
+
+        self.mount_a.run_shell(["mkdir", "phase2"])
+        self.mount_a.create_n_files("phase2/file", phase_2_files)
+
+        def unlink_and_count_ops(path, expected_deletions):
+            initial_ops = self.get_stat("objecter", "op")
+            initial_pq_executed = self.get_stat("purge_queue", "pq_executed")
+
+            self.mount_a.run_shell(["rm", "-rf", path])
+
+            self._wait_for_counter(
+                "purge_queue", "pq_executed", initial_pq_executed + expected_deletions
+            )
+
+            final_ops = self.get_stat("objecter", "op")
+
+            # Calculation of the *overhead* operations, i.e. do not include
+            # the operations where we actually delete files.
+            return final_ops - initial_ops - expected_deletions
+
+        self.fs.mds_asok(['flush', 'journal'])
+        phase1_ops = unlink_and_count_ops("phase1/", phase_1_files + 1)
+
+        self.fs.mds_asok(['flush', 'journal'])
+        phase2_ops = unlink_and_count_ops("phase2/", phase_2_files + 1)
+
+        log.info("Phase 1: {0}".format(phase1_ops))
+        log.info("Phase 2: {0}".format(phase2_ops))
+
+        # The success criterion is that deleting double the number
+        # of files doesn't generate double the number of overhead ops
+        # -- this comparison is a rough approximation of that rule.
+        self.assertTrue(phase2_ops < phase1_ops * 1.25)
+
+        # Finally, check that our activity did include properly quiescing
+        # the queue (i.e. call to Journaler::write_head in the right place),
+        # by restarting the MDS and checking that it doesn't try re-executing
+        # any of the work we did.
+        self.fs.mds_asok(['flush', 'journal'])  # flush to ensure no strays
+                                                # hanging around
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+        time.sleep(10)
+        self.assertEqual(self.get_stat("purge_queue", "pq_executed"), 0)
+
+    def test_replicated_delete_speed(self):
+        """
+        That deletions of replicated metadata are not pathologically slow
+        """
+        rank_0_id, rank_1_id = self._setup_two_ranks()
+
+        self.set_conf("mds.{0}".format(rank_1_id), 'mds_max_purge_files', "0")
+        self.mds_cluster.mds_fail_restart(rank_1_id)
+        self.fs.wait_for_daemons()
+
+        file_count = 10
+
+        self.mount_a.create_n_files("delete_me/file", file_count)
+
+        self._force_migrate(rank_1_id, "delete_me",
+                            self.mount_a.path_to_ino("delete_me/file_0"))
+
+        begin = datetime.datetime.now()
+        self.mount_a.run_shell(["rm", "-rf", Raw("delete_me/*")])
+        end = datetime.datetime.now()
+
+        # What we're really checking here is that we are completing client
+        # operations immediately rather than delaying until the next tick.
+        tick_period = float(self.fs.get_config("mds_tick_interval",
+                                               service_type="mds"))
+
+        duration = (end - begin).total_seconds()
+        self.assertLess(duration, (file_count * tick_period) * 0.25)
+
diff --git a/src/ceph/qa/tasks/cephfs/test_volume_client.py b/src/ceph/qa/tasks/cephfs/test_volume_client.py
new file mode 100644
index 0000000..0876af9
--- /dev/null
+++ b/src/ceph/qa/tasks/cephfs/test_volume_client.py
@@ -0,0 +1,1016 @@
+import json
+import logging
+import time
+import os
+from textwrap import dedent
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+from tasks.cephfs.fuse_mount import FuseMount
+from teuthology.exceptions import CommandFailedError
+
+log = logging.getLogger(__name__)
+
+
+class TestVolumeClient(CephFSTestCase):
+    # One for looking at the global filesystem, one for being
+    # the VolumeClient, two for mounting the created shares
+    CLIENTS_REQUIRED = 4
+
+    def _volume_client_python(self, client, script, vol_prefix=None, ns_prefix=None):
+        # Can't dedent this *and* the script we pass in, because they might have different
+        # levels of indentation to begin with, so leave this string zero-indented
+        if vol_prefix:
+            vol_prefix = "\"" + vol_prefix + "\""
+        if ns_prefix:
+            ns_prefix = "\"" + ns_prefix + "\""
+        return client.run_python("""
+from ceph_volume_client import CephFSVolumeClient, VolumePath
+import logging
+log = logging.getLogger("ceph_volume_client")
+log.addHandler(logging.StreamHandler())
+log.setLevel(logging.DEBUG)
+vc = CephFSVolumeClient("manila", "{conf_path}", "ceph", {vol_prefix}, {ns_prefix})
+vc.connect()
+{payload}
+vc.disconnect()
+        """.format(payload=script, conf_path=client.config_path, vol_prefix=vol_prefix, ns_prefix=ns_prefix))
+
+    def _sudo_write_file(self, remote, path, data):
+        """
+        Write data to a remote file as super user
+
+        :param remote: Remote site.
+        :param path: Path on the remote being written to.
+        :param data: Data to be written.
+
+        Both perms and owner are passed directly to chmod.
+        """
+        remote.run(
+            args=[
+                'sudo',
+                'python',
+                '-c',
+                'import shutil, sys; shutil.copyfileobj(sys.stdin, file(sys.argv[1], "wb"))',
+                path,
+            ],
+            stdin=data,
+        )
+
+    def _configure_vc_auth(self, mount, id_name):
+        """
+        Set up auth credentials for the VolumeClient user
+        """
+        out = self.fs.mon_manager.raw_cluster_cmd(
+            "auth", "get-or-create", "client.{name}".format(name=id_name),
+            "mds", "allow *",
+            "osd", "allow rw",
+            "mon", "allow *"
+        )
+        mount.client_id = id_name
+        self._sudo_write_file(mount.client_remote, mount.get_keyring_path(), out)
+        self.set_conf("client.{name}".format(name=id_name), "keyring", mount.get_keyring_path())
+
+    def _configure_guest_auth(self, volumeclient_mount, guest_mount,
+                              guest_entity, mount_path,
+                              namespace_prefix=None, readonly=False,
+                              tenant_id=None):
+        """
+        Set up auth credentials for the guest client to mount a volume.
+
+        :param volumeclient_mount: mount used as the handle for driving
+                                   volumeclient.
+        :param guest_mount: mount used by the guest client.
+        :param guest_entity: auth ID used by the guest client.
+        :param mount_path: path of the volume.
+        :param namespace_prefix: name prefix of the RADOS namespace, which
+                                 is used for the volume's layout.
+        :param readonly: defaults to False. If set to 'True' only read-only
+                         mount access is granted to the guest.
+        :param tenant_id: (OpenStack) tenant ID of the guest client.
+        """
+
+        head, volume_id = os.path.split(mount_path)
+        head, group_id = os.path.split(head)
+        head, volume_prefix = os.path.split(head)
+        volume_prefix = "/" + volume_prefix
+
+        # Authorize the guest client's auth ID to mount the volume.
+        key = self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            auth_result = vc.authorize(vp, "{guest_entity}", readonly={readonly},
+                                       tenant_id="{tenant_id}")
+            print auth_result['auth_key']
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            guest_entity=guest_entity,
+            readonly=readonly,
+            tenant_id=tenant_id)), volume_prefix, namespace_prefix
+        )
+
+        # CephFSVolumeClient's authorize() does not return the secret
+        # key to a caller who isn't multi-tenant aware. Explicitly
+        # query the key for such a client.
+        if not tenant_id:
+            key = self.fs.mon_manager.raw_cluster_cmd(
+            "auth", "get-key", "client.{name}".format(name=guest_entity),
+            )
+
+        # The guest auth ID should exist.
+        existing_ids = [a['entity'] for a in self.auth_list()]
+        self.assertIn("client.{0}".format(guest_entity), existing_ids)
+
+        # Create keyring file for the guest client.
+        keyring_txt = dedent("""
+        [client.{guest_entity}]
+            key = {key}
+
+        """.format(
+            guest_entity=guest_entity,
+            key=key
+        ))
+        guest_mount.client_id = guest_entity
+        self._sudo_write_file(guest_mount.client_remote,
+                              guest_mount.get_keyring_path(),
+                              keyring_txt)
+
+        # Add a guest client section to the ceph config file.
+        self.set_conf("client.{0}".format(guest_entity), "client quota", "True")
+        self.set_conf("client.{0}".format(guest_entity), "debug client", "20")
+        self.set_conf("client.{0}".format(guest_entity), "debug objecter", "20")
+        self.set_conf("client.{0}".format(guest_entity),
+                      "keyring", guest_mount.get_keyring_path())
+
+    def test_default_prefix(self):
+        group_id = "grpid"
+        volume_id = "volid"
+        DEFAULT_VOL_PREFIX = "volumes"
+        DEFAULT_NS_PREFIX = "fsvolumens_"
+
+        self.mount_b.umount_wait()
+        self._configure_vc_auth(self.mount_b, "manila")
+
+        #create a volume with default prefix
+        self._volume_client_python(self.mount_b, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.create_volume(vp, 10, data_isolated=True)
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+        )))
+
+        # The dir should be created
+        self.mount_a.stat(os.path.join(DEFAULT_VOL_PREFIX, group_id, volume_id))
+
+        #namespace should be set
+        ns_in_attr = self.mount_a.getfattr(os.path.join(DEFAULT_VOL_PREFIX, group_id, volume_id), "ceph.dir.layout.pool_namespace")
+        namespace = "{0}{1}".format(DEFAULT_NS_PREFIX, volume_id)
+        self.assertEqual(namespace, ns_in_attr)
+
+
+    def test_lifecycle(self):
+        """
+        General smoke test for create, extend, destroy
+        """
+
+        # I'm going to use mount_c later as a guest for mounting the created
+        # shares
+        self.mounts[2].umount_wait()
+
+        # I'm going to leave mount_b unmounted and just use it as a handle for
+        # driving volumeclient.  It's a little hacky but we don't have a more
+        # general concept for librados/libcephfs clients as opposed to full
+        # blown mounting clients.
+        self.mount_b.umount_wait()
+        self._configure_vc_auth(self.mount_b, "manila")
+
+        guest_entity = "guest"
+        group_id = "grpid"
+        volume_id = "volid"
+
+        volume_prefix = "/myprefix"
+        namespace_prefix = "mynsprefix_"
+
+        # Create a 100MB volume
+        volume_size = 100
+        mount_path = self._volume_client_python(self.mount_b, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            create_result = vc.create_volume(vp, 1024*1024*{volume_size})
+            print create_result['mount_path']
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            volume_size=volume_size
+        )), volume_prefix, namespace_prefix)
+
+        # The dir should be created
+        self.mount_a.stat(os.path.join("myprefix", group_id, volume_id))
+
+        # Authorize and configure credentials for the guest to mount the
+        # the volume.
+        self._configure_guest_auth(self.mount_b, self.mounts[2], guest_entity,
+                                   mount_path, namespace_prefix)
+        self.mounts[2].mount(mount_path=mount_path)
+
+        # The kernel client doesn't have the quota-based df behaviour,
+        # or quotas at all, so only exercise the client behaviour when
+        # running fuse.
+        if isinstance(self.mounts[2], FuseMount):
+            # df should see volume size, same as the quota set on volume's dir
+            self.assertEqual(self.mounts[2].df()['total'],
+                             volume_size * 1024 * 1024)
+            self.assertEqual(
+                    self.mount_a.getfattr(
+                        os.path.join(volume_prefix.strip("/"), group_id, volume_id),
+                        "ceph.quota.max_bytes"),
+                    "%s" % (volume_size * 1024 * 1024))
+
+            # df granularity is 4MB block so have to write at least that much
+            data_bin_mb = 4
+            self.mounts[2].write_n_mb("data.bin", data_bin_mb)
+
+            # Write something outside volume to check this space usage is
+            # not reported in the volume's DF.
+            other_bin_mb = 8
+            self.mount_a.write_n_mb("other.bin", other_bin_mb)
+
+            # global: df should see all the writes (data + other).  This is a >
+            # rather than a == because the global spaced used includes all pools
+            def check_df():
+                used = self.mount_a.df()['used']
+                return used >= (other_bin_mb * 1024 * 1024)
+
+            self.wait_until_true(check_df, timeout=30)
+
+            # Hack: do a metadata IO to kick rstats
+            self.mounts[2].run_shell(["touch", "foo"])
+
+            # volume: df should see the data_bin_mb consumed from quota, same
+            # as the rbytes for the volume's dir
+            self.wait_until_equal(
+                    lambda: self.mounts[2].df()['used'],
+                    data_bin_mb * 1024 * 1024, timeout=60)
+            self.wait_until_equal(
+                    lambda: self.mount_a.getfattr(
+                        os.path.join(volume_prefix.strip("/"), group_id, volume_id),
+                        "ceph.dir.rbytes"),
+                    "%s" % (data_bin_mb * 1024 * 1024), timeout=60)
+
+            # sync so that file data are persist to rados
+            self.mounts[2].run_shell(["sync"])
+
+            # Our data should stay in particular rados namespace
+            pool_name = self.mount_a.getfattr(os.path.join("myprefix", group_id, volume_id), "ceph.dir.layout.pool")
+            namespace = "{0}{1}".format(namespace_prefix, volume_id)
+            ns_in_attr = self.mount_a.getfattr(os.path.join("myprefix", group_id, volume_id), "ceph.dir.layout.pool_namespace")
+            self.assertEqual(namespace, ns_in_attr)
+
+            objects_in_ns = set(self.fs.rados(["ls"], pool=pool_name, namespace=namespace).split("\n"))
+            self.assertNotEqual(objects_in_ns, set())
+
+            # De-authorize the guest
+            self._volume_client_python(self.mount_b, dedent("""
+                vp = VolumePath("{group_id}", "{volume_id}")
+                vc.deauthorize(vp, "{guest_entity}")
+                vc.evict("{guest_entity}")
+            """.format(
+                group_id=group_id,
+                volume_id=volume_id,
+                guest_entity=guest_entity
+            )), volume_prefix, namespace_prefix)
+
+            # Once deauthorized, the client should be unable to do any more metadata ops
+            # The way that the client currently behaves here is to block (it acts like
+            # it has lost network, because there is nothing to tell it that is messages
+            # are being dropped because it's identity is gone)
+            background = self.mounts[2].write_n_mb("rogue.bin", 1, wait=False)
+            time.sleep(10)  # Approximate check for 'stuck' as 'still running after 10s'
+            self.assertFalse(background.finished)
+
+            # After deauthorisation, the client ID should be gone (this was the only
+            # volume it was authorised for)
+            self.assertNotIn("client.{0}".format(guest_entity), [e['entity'] for e in self.auth_list()])
+
+            # Clean up the dead mount (ceph-fuse's behaviour here is a bit undefined)
+            self.mounts[2].kill()
+            self.mounts[2].kill_cleanup()
+            try:
+                background.wait()
+            except CommandFailedError:
+                # We killed the mount out from under you
+                pass
+
+        self._volume_client_python(self.mount_b, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.delete_volume(vp)
+            vc.purge_volume(vp)
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+        )), volume_prefix, namespace_prefix)
+
+    def test_idempotency(self):
+        """
+        That the volumeclient interface works when calling everything twice
+        """
+        self.mount_b.umount_wait()
+        self._configure_vc_auth(self.mount_b, "manila")
+
+        guest_entity = "guest"
+        group_id = "grpid"
+        volume_id = "volid"
+        self._volume_client_python(self.mount_b, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.create_volume(vp, 10)
+            vc.create_volume(vp, 10)
+            vc.authorize(vp, "{guest_entity}")
+            vc.authorize(vp, "{guest_entity}")
+            vc.deauthorize(vp, "{guest_entity}")
+            vc.deauthorize(vp, "{guest_entity}")
+            vc.delete_volume(vp)
+            vc.delete_volume(vp)
+            vc.purge_volume(vp)
+            vc.purge_volume(vp)
+
+            vc.create_volume(vp, 10, data_isolated=True)
+            vc.create_volume(vp, 10, data_isolated=True)
+            vc.authorize(vp, "{guest_entity}")
+            vc.authorize(vp, "{guest_entity}")
+            vc.deauthorize(vp, "{guest_entity}")
+            vc.deauthorize(vp, "{guest_entity}")
+            vc.evict("{guest_entity}")
+            vc.evict("{guest_entity}")
+            vc.delete_volume(vp, data_isolated=True)
+            vc.delete_volume(vp, data_isolated=True)
+            vc.purge_volume(vp, data_isolated=True)
+            vc.purge_volume(vp, data_isolated=True)
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            guest_entity=guest_entity
+        )))
+
+    def test_data_isolated(self):
+        """
+        That data isolated shares get their own pool
+        :return:
+        """
+
+        # Because the teuthology config template sets mon_max_pg_per_osd to
+        # 10000 (i.e. it just tries to ignore health warnings), reset it to something
+        # sane before using volume_client, to avoid creating pools with absurdly large
+        # numbers of PGs.
+        self.set_conf("global", "mon max pg per osd", "300")
+        for mon_daemon_state in self.ctx.daemons.iter_daemons_of_role('mon'):
+            mon_daemon_state.restart()
+
+        self.mount_b.umount_wait()
+        self._configure_vc_auth(self.mount_b, "manila")
+
+        # Calculate how many PGs we'll expect the new volume pool to have
+        osd_map = json.loads(self.fs.mon_manager.raw_cluster_cmd('osd', 'dump', '--format=json-pretty'))
+        max_per_osd = int(self.fs.get_config('mon_max_pg_per_osd'))
+        osd_count = len(osd_map['osds'])
+        max_overall = osd_count * max_per_osd
+
+        existing_pg_count = 0
+        for p in osd_map['pools']:
+            existing_pg_count += p['pg_num']
+
+        expected_pg_num = (max_overall - existing_pg_count) / 10
+        log.info("max_per_osd {0}".format(max_per_osd))
+        log.info("osd_count {0}".format(osd_count))
+        log.info("max_overall {0}".format(max_overall))
+        log.info("existing_pg_count {0}".format(existing_pg_count))
+        log.info("expected_pg_num {0}".format(expected_pg_num))
+
+        pools_a = json.loads(self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json-pretty"))['pools']
+
+        group_id = "grpid"
+        volume_id = "volid"
+        self._volume_client_python(self.mount_b, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.create_volume(vp, 10, data_isolated=True)
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+        )))
+
+        pools_b = json.loads(self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json-pretty"))['pools']
+
+        # Should have created one new pool
+        new_pools = set(p['pool_name'] for p in pools_b) - set([p['pool_name'] for p in pools_a])
+        self.assertEqual(len(new_pools), 1)
+
+        # It should have followed the heuristic for PG count
+        # (this is an overly strict test condition, so we may want to remove
+        #  it at some point as/when the logic gets fancier)
+        created_pg_num = self.fs.mon_manager.get_pool_property(list(new_pools)[0], "pg_num")
+        self.assertEqual(expected_pg_num, created_pg_num)
+
+    def test_15303(self):
+        """
+        Reproducer for #15303 "Client holds incorrect complete flag on dir
+        after losing caps" (http://tracker.ceph.com/issues/15303)
+        """
+        for m in self.mounts:
+            m.umount_wait()
+
+        # Create a dir on mount A
+        self.mount_a.mount()
+        self.mount_a.run_shell(["mkdir", "parent1"])
+        self.mount_a.run_shell(["mkdir", "parent2"])
+        self.mount_a.run_shell(["mkdir", "parent1/mydir"])
+
+        # Put some files in it from mount B
+        self.mount_b.mount()
+        self.mount_b.run_shell(["touch", "parent1/mydir/afile"])
+        self.mount_b.umount_wait()
+
+        # List the dir's contents on mount A
+        self.assertListEqual(self.mount_a.ls("parent1/mydir"),
+                             ["afile"])
+
+    def test_evict_client(self):
+        """
+        That a volume client can be evicted based on its auth ID and the volume
+        path it has mounted.
+        """
+
+        if not isinstance(self.mount_a, FuseMount):
+            self.skipTest("Requires FUSE client to inject client metadata")
+
+        # mounts[1] would be used as handle for driving VolumeClient. mounts[2]
+        # and mounts[3] would be used as guests to mount the volumes/shares.
+
+        for i in range(1, 4):
+            self.mounts[i].umount_wait()
+
+        volumeclient_mount = self.mounts[1]
+        self._configure_vc_auth(volumeclient_mount, "manila")
+        guest_mounts = (self.mounts[2], self.mounts[3])
+
+        guest_entity = "guest"
+        group_id = "grpid"
+        mount_paths = []
+        volume_ids = []
+
+        # Create two volumes. Authorize 'guest' auth ID to mount the two
+        # volumes. Mount the two volumes. Write data to the volumes.
+        for i in range(2):
+            # Create volume.
+            volume_ids.append("volid_{0}".format(str(i)))
+            mount_paths.append(
+                self._volume_client_python(volumeclient_mount, dedent("""
+                    vp = VolumePath("{group_id}", "{volume_id}")
+                    create_result = vc.create_volume(vp, 10 * 1024 * 1024)
+                    print create_result['mount_path']
+                """.format(
+                    group_id=group_id,
+                    volume_id=volume_ids[i]
+            ))))
+
+            # Authorize 'guest' auth ID to mount the volume.
+            self._configure_guest_auth(volumeclient_mount, guest_mounts[i],
+                                       guest_entity, mount_paths[i])
+
+            # Mount the volume.
+            guest_mounts[i].mountpoint_dir_name = 'mnt.{id}.{suffix}'.format(
+                id=guest_entity, suffix=str(i))
+            guest_mounts[i].mount(mount_path=mount_paths[i])
+            guest_mounts[i].write_n_mb("data.bin", 1)
+
+
+        # Evict client, guest_mounts[0], using auth ID 'guest' and has mounted
+        # one volume.
+        self._volume_client_python(self.mount_b, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.deauthorize(vp, "{guest_entity}")
+            vc.evict("{guest_entity}", volume_path=vp)
+        """.format(
+            group_id=group_id,
+            volume_id=volume_ids[0],
+            guest_entity=guest_entity
+        )))
+
+        # Evicted guest client, guest_mounts[0], should not be able to do
+        # anymore metadata ops.  It should start failing all operations
+        # when it sees that its own address is in the blacklist.
+        try:
+            guest_mounts[0].write_n_mb("rogue.bin", 1)
+        except CommandFailedError:
+            pass
+        else:
+            raise RuntimeError("post-eviction write should have failed!")
+
+        # The blacklisted guest client should now be unmountable
+        guest_mounts[0].umount_wait()
+
+        # Guest client, guest_mounts[1], using the same auth ID 'guest', but
+        # has mounted the other volume, should be able to use its volume
+        # unaffected.
+        guest_mounts[1].write_n_mb("data.bin.1", 1)
+
+        # Cleanup.
+        for i in range(2):
+            self._volume_client_python(volumeclient_mount, dedent("""
+                vp = VolumePath("{group_id}", "{volume_id}")
+                vc.deauthorize(vp, "{guest_entity}")
+                vc.delete_volume(vp)
+                vc.purge_volume(vp)
+            """.format(
+                group_id=group_id,
+                volume_id=volume_ids[i],
+                guest_entity=guest_entity
+            )))
+
+
+    def test_purge(self):
+        """
+        Reproducer for #15266, exception trying to purge volumes that
+        contain non-ascii filenames.
+
+        Additionally test any other purge corner cases here.
+        """
+        # I'm going to leave mount_b unmounted and just use it as a handle for
+        # driving volumeclient.  It's a little hacky but we don't have a more
+        # general concept for librados/libcephfs clients as opposed to full
+        # blown mounting clients.
+        self.mount_b.umount_wait()
+        self._configure_vc_auth(self.mount_b, "manila")
+
+        group_id = "grpid"
+        # Use a unicode volume ID (like Manila), to reproduce #15266
+        volume_id = u"volid"
+
+        # Create
+        mount_path = self._volume_client_python(self.mount_b, dedent("""
+            vp = VolumePath("{group_id}", u"{volume_id}")
+            create_result = vc.create_volume(vp, 10)
+            print create_result['mount_path']
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id
+        )))
+
+        # Strip leading "/"
+        mount_path = mount_path[1:]
+
+        # A file with non-ascii characters
+        self.mount_a.run_shell(["touch", os.path.join(mount_path, u"b\u00F6b")])
+
+        # A file with no permissions to do anything
+        self.mount_a.run_shell(["touch", os.path.join(mount_path, "noperms")])
+        self.mount_a.run_shell(["chmod", "0000", os.path.join(mount_path, "noperms")])
+
+        self._volume_client_python(self.mount_b, dedent("""
+            vp = VolumePath("{group_id}", u"{volume_id}")
+            vc.delete_volume(vp)
+            vc.purge_volume(vp)
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id
+        )))
+
+        # Check it's really gone
+        self.assertEqual(self.mount_a.ls("volumes/_deleting"), [])
+        self.assertEqual(self.mount_a.ls("volumes/"), ["_deleting", group_id])
+
+    def test_readonly_authorization(self):
+        """
+        That guest clients can be restricted to read-only mounts of volumes.
+        """
+
+        volumeclient_mount = self.mounts[1]
+        guest_mount = self.mounts[2]
+        volumeclient_mount.umount_wait()
+        guest_mount.umount_wait()
+
+        # Configure volumeclient_mount as the handle for driving volumeclient.
+        self._configure_vc_auth(volumeclient_mount, "manila")
+
+        guest_entity = "guest"
+        group_id = "grpid"
+        volume_id = "volid"
+
+        # Create a volume.
+        mount_path = self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            create_result = vc.create_volume(vp, 1024*1024*10)
+            print create_result['mount_path']
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+        )))
+
+        # Authorize and configure credentials for the guest to mount the
+        # the volume with read-write access.
+        self._configure_guest_auth(volumeclient_mount, guest_mount, guest_entity,
+                                   mount_path, readonly=False)
+
+        # Mount the volume, and write to it.
+        guest_mount.mount(mount_path=mount_path)
+        guest_mount.write_n_mb("data.bin", 1)
+
+        # Change the guest auth ID's authorization to read-only mount access.
+        self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.deauthorize(vp, "{guest_entity}")
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            guest_entity=guest_entity
+        )))
+        self._configure_guest_auth(volumeclient_mount, guest_mount, guest_entity,
+                                   mount_path, readonly=True)
+
+        # The effect of the change in access level to read-only is not
+        # immediate. The guest sees the change only after a remount of
+        # the volume.
+        guest_mount.umount_wait()
+        guest_mount.mount(mount_path=mount_path)
+
+        # Read existing content of the volume.
+        self.assertListEqual(guest_mount.ls(guest_mount.mountpoint), ["data.bin"])
+        # Cannot write into read-only volume.
+        with self.assertRaises(CommandFailedError):
+            guest_mount.write_n_mb("rogue.bin", 1)
+
+    def test_get_authorized_ids(self):
+        """
+        That for a volume, the authorized IDs and their access levels
+        can be obtained using CephFSVolumeClient's get_authorized_ids().
+        """
+        volumeclient_mount = self.mounts[1]
+        volumeclient_mount.umount_wait()
+
+        # Configure volumeclient_mount as the handle for driving volumeclient.
+        self._configure_vc_auth(volumeclient_mount, "manila")
+
+        group_id = "grpid"
+        volume_id = "volid"
+        guest_entity_1 = "guest1"
+        guest_entity_2 = "guest2"
+
+        log.info("print group ID: {0}".format(group_id))
+
+        # Create a volume.
+        auths = self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.create_volume(vp, 1024*1024*10)
+            auths = vc.get_authorized_ids(vp)
+            print auths
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+        )))
+        # Check the list of authorized IDs for the volume.
+        expected_result = None
+        self.assertEqual(str(expected_result), auths)
+
+        # Allow two auth IDs access to the volume.
+        auths = self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.authorize(vp, "{guest_entity_1}", readonly=False)
+            vc.authorize(vp, "{guest_entity_2}", readonly=True)
+            auths = vc.get_authorized_ids(vp)
+            print auths
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            guest_entity_1=guest_entity_1,
+            guest_entity_2=guest_entity_2,
+        )))
+        # Check the list of authorized IDs and their access levels.
+        expected_result = [(u'guest1', u'rw'), (u'guest2', u'r')]
+        self.assertItemsEqual(str(expected_result), auths)
+
+        # Disallow both the auth IDs' access to the volume.
+        auths = self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.deauthorize(vp, "{guest_entity_1}")
+            vc.deauthorize(vp, "{guest_entity_2}")
+            auths = vc.get_authorized_ids(vp)
+            print auths
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            guest_entity_1=guest_entity_1,
+            guest_entity_2=guest_entity_2,
+        )))
+        # Check the list of authorized IDs for the volume.
+        expected_result = None
+        self.assertItemsEqual(str(expected_result), auths)
+
+    def test_multitenant_volumes(self):
+        """
+        That volume access can be restricted to a tenant.
+
+        That metadata used to enforce tenant isolation of
+        volumes is stored as a two-way mapping between auth
+        IDs and volumes that they're authorized to access.
+        """
+        volumeclient_mount = self.mounts[1]
+        volumeclient_mount.umount_wait()
+
+        # Configure volumeclient_mount as the handle for driving volumeclient.
+        self._configure_vc_auth(volumeclient_mount, "manila")
+
+        group_id = "groupid"
+        volume_id = "volumeid"
+
+        # Guest clients belonging to different tenants, but using the same
+        # auth ID.
+        auth_id = "guest"
+        guestclient_1 = {
+            "auth_id": auth_id,
+            "tenant_id": "tenant1",
+        }
+        guestclient_2 = {
+            "auth_id": auth_id,
+            "tenant_id": "tenant2",
+        }
+
+        # Create a volume.
+        self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.create_volume(vp, 1024*1024*10)
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+        )))
+
+        # Check that volume metadata file is created on volume creation.
+        vol_metadata_filename = "_{0}:{1}.meta".format(group_id, volume_id)
+        self.assertIn(vol_metadata_filename, self.mounts[0].ls("volumes"))
+
+        # Authorize 'guestclient_1', using auth ID 'guest' and belonging to
+        # 'tenant1', with 'rw' access to the volume.
+        self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.authorize(vp, "{auth_id}", tenant_id="{tenant_id}")
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            auth_id=guestclient_1["auth_id"],
+            tenant_id=guestclient_1["tenant_id"]
+        )))
+
+        # Check that auth metadata file for auth ID 'guest', is
+        # created on authorizing 'guest' access to the volume.
+        auth_metadata_filename = "${0}.meta".format(guestclient_1["auth_id"])
+        self.assertIn(auth_metadata_filename, self.mounts[0].ls("volumes"))
+
+        # Verify that the auth metadata file stores the tenant ID that the
+        # auth ID belongs to, the auth ID's authorized access levels
+        # for different volumes, versioning details, etc.
+        expected_auth_metadata = {
+            u"version": 2,
+            u"compat_version": 1,
+            u"dirty": False,
+            u"tenant_id": u"tenant1",
+            u"volumes": {
+                u"groupid/volumeid": {
+                    u"dirty": False,
+                    u"access_level": u"rw",
+                }
+            }
+        }
+
+        auth_metadata = self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            auth_metadata = vc._auth_metadata_get("{auth_id}")
+            print auth_metadata
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            auth_id=guestclient_1["auth_id"],
+        )))
+
+        self.assertItemsEqual(str(expected_auth_metadata), auth_metadata)
+
+        # Verify that the volume metadata file stores info about auth IDs
+        # and their access levels to the volume, versioning details, etc.
+        expected_vol_metadata = {
+            u"version": 2,
+            u"compat_version": 1,
+            u"auths": {
+                u"guest": {
+                    u"dirty": False,
+                    u"access_level": u"rw"
+                }
+            }
+        }
+
+        vol_metadata = self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            volume_metadata = vc._volume_metadata_get(vp)
+            print volume_metadata
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+        )))
+        self.assertItemsEqual(str(expected_vol_metadata), vol_metadata)
+
+        # Cannot authorize 'guestclient_2' to access the volume.
+        # It uses auth ID 'guest', which has already been used by a
+        # 'guestclient_1' belonging to an another tenant for accessing
+        # the volume.
+        with self.assertRaises(CommandFailedError):
+            self._volume_client_python(volumeclient_mount, dedent("""
+                vp = VolumePath("{group_id}", "{volume_id}")
+                vc.authorize(vp, "{auth_id}", tenant_id="{tenant_id}")
+            """.format(
+                group_id=group_id,
+                volume_id=volume_id,
+                auth_id=guestclient_2["auth_id"],
+                tenant_id=guestclient_2["tenant_id"]
+            )))
+
+        # Check that auth metadata file is cleaned up on removing
+        # auth ID's only access to a volume.
+        self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.deauthorize(vp, "{guest_entity}")
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            guest_entity=guestclient_1["auth_id"]
+        )))
+
+        self.assertNotIn(auth_metadata_filename, self.mounts[0].ls("volumes"))
+
+        # Check that volume metadata file is cleaned up on volume deletion.
+        self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.delete_volume(vp)
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+        )))
+        self.assertNotIn(vol_metadata_filename, self.mounts[0].ls("volumes"))
+
+    def test_recover_metadata(self):
+        """
+        That volume client can recover from partial auth updates using
+        metadata files, which store auth info and its update status info.
+        """
+        volumeclient_mount = self.mounts[1]
+        volumeclient_mount.umount_wait()
+
+        # Configure volumeclient_mount as the handle for driving volumeclient.
+        self._configure_vc_auth(volumeclient_mount, "manila")
+
+        group_id = "groupid"
+        volume_id = "volumeid"
+
+        guestclient = {
+            "auth_id": "guest",
+            "tenant_id": "tenant",
+        }
+
+        # Create a volume.
+        self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.create_volume(vp, 1024*1024*10)
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+        )))
+
+        # Authorize 'guestclient' access to the volume.
+        self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            vc.authorize(vp, "{auth_id}", tenant_id="{tenant_id}")
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            auth_id=guestclient["auth_id"],
+            tenant_id=guestclient["tenant_id"]
+        )))
+
+        # Check that auth metadata file for auth ID 'guest' is created.
+        auth_metadata_filename = "${0}.meta".format(guestclient["auth_id"])
+        self.assertIn(auth_metadata_filename, self.mounts[0].ls("volumes"))
+
+        # Induce partial auth update state by modifying the auth metadata file,
+        # and then run recovery procedure.
+        self._volume_client_python(volumeclient_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            auth_metadata = vc._auth_metadata_get("{auth_id}")
+            auth_metadata['dirty'] = True
+            vc._auth_metadata_set("{auth_id}", auth_metadata)
+            vc.recover()
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id,
+            auth_id=guestclient["auth_id"],
+        )))
+
+    def test_put_object(self):
+        vc_mount = self.mounts[1]
+        vc_mount.umount_wait()
+        self._configure_vc_auth(vc_mount, "manila")
+
+        obj_data = 'test data'
+        obj_name = 'test_vc_obj_1'
+        pool_name = self.fs.get_data_pool_names()[0]
+
+        self._volume_client_python(vc_mount, dedent("""
+            vc.put_object("{pool_name}", "{obj_name}", b"{obj_data}")
+        """.format(
+            pool_name = pool_name,
+            obj_name = obj_name,
+            obj_data = obj_data
+        )))
+
+        read_data = self.fs.rados(['get', obj_name, '-'], pool=pool_name)
+        self.assertEqual(obj_data, read_data)
+
+    def test_get_object(self):
+        vc_mount = self.mounts[1]
+        vc_mount.umount_wait()
+        self._configure_vc_auth(vc_mount, "manila")
+
+        obj_data = 'test_data'
+        obj_name = 'test_vc_ob_2'
+        pool_name = self.fs.get_data_pool_names()[0]
+
+        self.fs.rados(['put', obj_name, '-'], pool=pool_name, stdin_data=obj_data)
+
+        self._volume_client_python(vc_mount, dedent("""
+            data_read = vc.get_object("{pool_name}", "{obj_name}")
+            assert data_read == b"{obj_data}"
+        """.format(
+            pool_name = pool_name,
+            obj_name = obj_name,
+            obj_data = obj_data
+        )))
+
+    def test_delete_object(self):
+        vc_mount = self.mounts[1]
+        vc_mount.umount_wait()
+        self._configure_vc_auth(vc_mount, "manila")
+
+        obj_data = 'test data'
+        obj_name = 'test_vc_obj_3'
+        pool_name = self.fs.get_data_pool_names()[0]
+
+        self.fs.rados(['put', obj_name, '-'], pool=pool_name, stdin_data=obj_data)
+
+        self._volume_client_python(vc_mount, dedent("""
+            data_read = vc.delete_object("{pool_name}", "{obj_name}")
+        """.format(
+            pool_name = pool_name,
+            obj_name = obj_name,
+        )))
+
+        with self.assertRaises(CommandFailedError):
+            self.fs.rados(['stat', obj_name], pool=pool_name)
+
+        # Check idempotency -- no error raised trying to delete non-existent
+        # object
+        self._volume_client_python(vc_mount, dedent("""
+            data_read = vc.delete_object("{pool_name}", "{obj_name}")
+        """.format(
+            pool_name = pool_name,
+            obj_name = obj_name,
+        )))
+
+    def test_21501(self):
+        """
+        Reproducer for #21501 "ceph_volume_client: sets invalid caps for
+        existing IDs with no caps" (http://tracker.ceph.com/issues/21501)
+        """
+
+        vc_mount = self.mounts[1]
+        vc_mount.umount_wait()
+
+        # Configure vc_mount as the handle for driving volumeclient
+        self._configure_vc_auth(vc_mount, "manila")
+
+        # Create a volume
+        group_id = "grpid"
+        volume_id = "volid"
+        mount_path = self._volume_client_python(vc_mount, dedent("""
+            vp = VolumePath("{group_id}", "{volume_id}")
+            create_result = vc.create_volume(vp, 1024*1024*10)
+            print create_result['mount_path']
+        """.format(
+            group_id=group_id,
+            volume_id=volume_id
+        )))
+
+        # Create an auth ID with no caps
+        guest_id = '21501'
+        self.fs.mon_manager.raw_cluster_cmd_result(
+            'auth', 'get-or-create', 'client.{0}'.format(guest_id))
+
+        guest_mount = self.mounts[2]
+        guest_mount.umount_wait()
+
+        # Set auth caps for the auth ID using the volumeclient
+        self._configure_guest_auth(vc_mount, guest_mount, guest_id, mount_path)
+
+        # Mount the volume in the guest using the auth ID to assert that the
+        # auth caps are valid
+        guest_mount.mount(mount_path=mount_path)