Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 1409 insertions, 0 deletions

diff --git a/kernel/fs/gfs2/ops_fstype.c b/kernel/fs/gfs2/ops_fstype.c
new file mode 100644
index 000000000..35b49f44c
--- /dev/null
+++ b/kernel/fs/gfs2/ops_fstype.c
@@ -0,0 +1,1409 @@
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License version 2.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/buffer_head.h>
+#include <linux/blkdev.h>
+#include <linux/kthread.h>
+#include <linux/export.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/gfs2_ondisk.h>
+#include <linux/quotaops.h>
+#include <linux/lockdep.h>
+#include <linux/module.h>
+
+#include "gfs2.h"
+#include "incore.h"
+#include "bmap.h"
+#include "glock.h"
+#include "glops.h"
+#include "inode.h"
+#include "recovery.h"
+#include "rgrp.h"
+#include "super.h"
+#include "sys.h"
+#include "util.h"
+#include "log.h"
+#include "quota.h"
+#include "dir.h"
+#include "meta_io.h"
+#include "trace_gfs2.h"
+
+#define DO 0
+#define UNDO 1
+
+/**
+ * gfs2_tune_init - Fill a gfs2_tune structure with default values
+ * @gt: tune
+ *
+ */
+
+static void gfs2_tune_init(struct gfs2_tune *gt)
+{
+	spin_lock_init(&gt->gt_spin);
+
+	gt->gt_quota_warn_period = 10;
+	gt->gt_quota_scale_num = 1;
+	gt->gt_quota_scale_den = 1;
+	gt->gt_new_files_jdata = 0;
+	gt->gt_max_readahead = 1 << 18;
+	gt->gt_complain_secs = 10;
+}
+
+static struct gfs2_sbd *init_sbd(struct super_block *sb)
+{
+	struct gfs2_sbd *sdp;
+	struct address_space *mapping;
+
+	sdp = kzalloc(sizeof(struct gfs2_sbd), GFP_KERNEL);
+	if (!sdp)
+		return NULL;
+
+	sb->s_fs_info = sdp;
+	sdp->sd_vfs = sb;
+	sdp->sd_lkstats = alloc_percpu(struct gfs2_pcpu_lkstats);
+	if (!sdp->sd_lkstats) {
+		kfree(sdp);
+		return NULL;
+	}
+
+	set_bit(SDF_NOJOURNALID, &sdp->sd_flags);
+	gfs2_tune_init(&sdp->sd_tune);
+
+	init_waitqueue_head(&sdp->sd_glock_wait);
+	atomic_set(&sdp->sd_glock_disposal, 0);
+	init_completion(&sdp->sd_locking_init);
+	init_completion(&sdp->sd_wdack);
+	spin_lock_init(&sdp->sd_statfs_spin);
+
+	spin_lock_init(&sdp->sd_rindex_spin);
+	sdp->sd_rindex_tree.rb_node = NULL;
+
+	INIT_LIST_HEAD(&sdp->sd_jindex_list);
+	spin_lock_init(&sdp->sd_jindex_spin);
+	mutex_init(&sdp->sd_jindex_mutex);
+	init_completion(&sdp->sd_journal_ready);
+
+	INIT_LIST_HEAD(&sdp->sd_quota_list);
+	mutex_init(&sdp->sd_quota_mutex);
+	mutex_init(&sdp->sd_quota_sync_mutex);
+	init_waitqueue_head(&sdp->sd_quota_wait);
+	INIT_LIST_HEAD(&sdp->sd_trunc_list);
+	spin_lock_init(&sdp->sd_trunc_lock);
+	spin_lock_init(&sdp->sd_bitmap_lock);
+
+	mapping = &sdp->sd_aspace;
+
+	address_space_init_once(mapping);
+	mapping->a_ops = &gfs2_rgrp_aops;
+	mapping->host = sb->s_bdev->bd_inode;
+	mapping->flags = 0;
+	mapping_set_gfp_mask(mapping, GFP_NOFS);
+	mapping->private_data = NULL;
+	mapping->writeback_index = 0;
+
+	spin_lock_init(&sdp->sd_log_lock);
+	atomic_set(&sdp->sd_log_pinned, 0);
+	INIT_LIST_HEAD(&sdp->sd_log_le_revoke);
+	INIT_LIST_HEAD(&sdp->sd_log_le_ordered);
+	spin_lock_init(&sdp->sd_ordered_lock);
+
+	init_waitqueue_head(&sdp->sd_log_waitq);
+	init_waitqueue_head(&sdp->sd_logd_waitq);
+	spin_lock_init(&sdp->sd_ail_lock);
+	INIT_LIST_HEAD(&sdp->sd_ail1_list);
+	INIT_LIST_HEAD(&sdp->sd_ail2_list);
+
+	init_rwsem(&sdp->sd_log_flush_lock);
+	atomic_set(&sdp->sd_log_in_flight, 0);
+	atomic_set(&sdp->sd_reserving_log, 0);
+	init_waitqueue_head(&sdp->sd_reserving_log_wait);
+	init_waitqueue_head(&sdp->sd_log_flush_wait);
+	atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
+	mutex_init(&sdp->sd_freeze_mutex);
+
+	return sdp;
+}
+
+
+/**
+ * gfs2_check_sb - Check superblock
+ * @sdp: the filesystem
+ * @sb: The superblock
+ * @silent: Don't print a message if the check fails
+ *
+ * Checks the version code of the FS is one that we understand how to
+ * read and that the sizes of the various on-disk structures have not
+ * changed.
+ */
+
+static int gfs2_check_sb(struct gfs2_sbd *sdp, int silent)
+{
+	struct gfs2_sb_host *sb = &sdp->sd_sb;
+
+	if (sb->sb_magic != GFS2_MAGIC ||
+	    sb->sb_type != GFS2_METATYPE_SB) {
+		if (!silent)
+			pr_warn("not a GFS2 filesystem\n");
+		return -EINVAL;
+	}
+
+	/*  If format numbers match exactly, we're done.  */
+
+	if (sb->sb_fs_format == GFS2_FORMAT_FS &&
+	    sb->sb_multihost_format == GFS2_FORMAT_MULTI)
+		return 0;
+
+	fs_warn(sdp, "Unknown on-disk format, unable to mount\n");
+
+	return -EINVAL;
+}
+
+static void end_bio_io_page(struct bio *bio, int error)
+{
+	struct page *page = bio->bi_private;
+
+	if (!error)
+		SetPageUptodate(page);
+	else
+		pr_warn("error %d reading superblock\n", error);
+	unlock_page(page);
+}
+
+static void gfs2_sb_in(struct gfs2_sbd *sdp, const void *buf)
+{
+	struct gfs2_sb_host *sb = &sdp->sd_sb;
+	struct super_block *s = sdp->sd_vfs;
+	const struct gfs2_sb *str = buf;
+
+	sb->sb_magic = be32_to_cpu(str->sb_header.mh_magic);
+	sb->sb_type = be32_to_cpu(str->sb_header.mh_type);
+	sb->sb_format = be32_to_cpu(str->sb_header.mh_format);
+	sb->sb_fs_format = be32_to_cpu(str->sb_fs_format);
+	sb->sb_multihost_format = be32_to_cpu(str->sb_multihost_format);
+	sb->sb_bsize = be32_to_cpu(str->sb_bsize);
+	sb->sb_bsize_shift = be32_to_cpu(str->sb_bsize_shift);
+	sb->sb_master_dir.no_addr = be64_to_cpu(str->sb_master_dir.no_addr);
+	sb->sb_master_dir.no_formal_ino = be64_to_cpu(str->sb_master_dir.no_formal_ino);
+	sb->sb_root_dir.no_addr = be64_to_cpu(str->sb_root_dir.no_addr);
+	sb->sb_root_dir.no_formal_ino = be64_to_cpu(str->sb_root_dir.no_formal_ino);
+
+	memcpy(sb->sb_lockproto, str->sb_lockproto, GFS2_LOCKNAME_LEN);
+	memcpy(sb->sb_locktable, str->sb_locktable, GFS2_LOCKNAME_LEN);
+	memcpy(s->s_uuid, str->sb_uuid, 16);
+}
+
+/**
+ * gfs2_read_super - Read the gfs2 super block from disk
+ * @sdp: The GFS2 super block
+ * @sector: The location of the super block
+ * @error: The error code to return
+ *
+ * This uses the bio functions to read the super block from disk
+ * because we want to be 100% sure that we never read cached data.
+ * A super block is read twice only during each GFS2 mount and is
+ * never written to by the filesystem. The first time its read no
+ * locks are held, and the only details which are looked at are those
+ * relating to the locking protocol. Once locking is up and working,
+ * the sb is read again under the lock to establish the location of
+ * the master directory (contains pointers to journals etc) and the
+ * root directory.
+ *
+ * Returns: 0 on success or error
+ */
+
+static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector, int silent)
+{
+	struct super_block *sb = sdp->sd_vfs;
+	struct gfs2_sb *p;
+	struct page *page;
+	struct bio *bio;
+
+	page = alloc_page(GFP_NOFS);
+	if (unlikely(!page))
+		return -ENOMEM;
+
+	ClearPageUptodate(page);
+	ClearPageDirty(page);
+	lock_page(page);
+
+	bio = bio_alloc(GFP_NOFS, 1);
+	bio->bi_iter.bi_sector = sector * (sb->s_blocksize >> 9);
+	bio->bi_bdev = sb->s_bdev;
+	bio_add_page(bio, page, PAGE_SIZE, 0);
+
+	bio->bi_end_io = end_bio_io_page;
+	bio->bi_private = page;
+	submit_bio(READ_SYNC | REQ_META, bio);
+	wait_on_page_locked(page);
+	bio_put(bio);
+	if (!PageUptodate(page)) {
+		__free_page(page);
+		return -EIO;
+	}
+	p = kmap(page);
+	gfs2_sb_in(sdp, p);
+	kunmap(page);
+	__free_page(page);
+	return gfs2_check_sb(sdp, silent);
+}
+
+/**
+ * gfs2_read_sb - Read super block
+ * @sdp: The GFS2 superblock
+ * @silent: Don't print message if mount fails
+ *
+ */
+
+static int gfs2_read_sb(struct gfs2_sbd *sdp, int silent)
+{
+	u32 hash_blocks, ind_blocks, leaf_blocks;
+	u32 tmp_blocks;
+	unsigned int x;
+	int error;
+
+	error = gfs2_read_super(sdp, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift, silent);
+	if (error) {
+		if (!silent)
+			fs_err(sdp, "can't read superblock\n");
+		return error;
+	}
+
+	sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -
+			       GFS2_BASIC_BLOCK_SHIFT;
+	sdp->sd_fsb2bb = 1 << sdp->sd_fsb2bb_shift;
+	sdp->sd_diptrs = (sdp->sd_sb.sb_bsize -
+			  sizeof(struct gfs2_dinode)) / sizeof(u64);
+	sdp->sd_inptrs = (sdp->sd_sb.sb_bsize -
+			  sizeof(struct gfs2_meta_header)) / sizeof(u64);
+	sdp->sd_jbsize = sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header);
+	sdp->sd_hash_bsize = sdp->sd_sb.sb_bsize / 2;
+	sdp->sd_hash_bsize_shift = sdp->sd_sb.sb_bsize_shift - 1;
+	sdp->sd_hash_ptrs = sdp->sd_hash_bsize / sizeof(u64);
+	sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
+				sizeof(struct gfs2_meta_header)) /
+			        sizeof(struct gfs2_quota_change);
+	sdp->sd_blocks_per_bitmap = (sdp->sd_sb.sb_bsize -
+				     sizeof(struct gfs2_meta_header))
+		* GFS2_NBBY; /* not the rgrp bitmap, subsequent bitmaps only */
+
+	/* Compute maximum reservation required to add a entry to a directory */
+
+	hash_blocks = DIV_ROUND_UP(sizeof(u64) * (1 << GFS2_DIR_MAX_DEPTH),
+			     sdp->sd_jbsize);
+
+	ind_blocks = 0;
+	for (tmp_blocks = hash_blocks; tmp_blocks > sdp->sd_diptrs;) {
+		tmp_blocks = DIV_ROUND_UP(tmp_blocks, sdp->sd_inptrs);
+		ind_blocks += tmp_blocks;
+	}
+
+	leaf_blocks = 2 + GFS2_DIR_MAX_DEPTH;
+
+	sdp->sd_max_dirres = hash_blocks + ind_blocks + leaf_blocks;
+
+	sdp->sd_heightsize[0] = sdp->sd_sb.sb_bsize -
+				sizeof(struct gfs2_dinode);
+	sdp->sd_heightsize[1] = sdp->sd_sb.sb_bsize * sdp->sd_diptrs;
+	for (x = 2;; x++) {
+		u64 space, d;
+		u32 m;
+
+		space = sdp->sd_heightsize[x - 1] * sdp->sd_inptrs;
+		d = space;
+		m = do_div(d, sdp->sd_inptrs);
+
+		if (d != sdp->sd_heightsize[x - 1] || m)
+			break;
+		sdp->sd_heightsize[x] = space;
+	}
+	sdp->sd_max_height = x;
+	sdp->sd_heightsize[x] = ~0;
+	gfs2_assert(sdp, sdp->sd_max_height <= GFS2_MAX_META_HEIGHT);
+
+	sdp->sd_jheightsize[0] = sdp->sd_sb.sb_bsize -
+				 sizeof(struct gfs2_dinode);
+	sdp->sd_jheightsize[1] = sdp->sd_jbsize * sdp->sd_diptrs;
+	for (x = 2;; x++) {
+		u64 space, d;
+		u32 m;
+
+		space = sdp->sd_jheightsize[x - 1] * sdp->sd_inptrs;
+		d = space;
+		m = do_div(d, sdp->sd_inptrs);
+
+		if (d != sdp->sd_jheightsize[x - 1] || m)
+			break;
+		sdp->sd_jheightsize[x] = space;
+	}
+	sdp->sd_max_jheight = x;
+	sdp->sd_jheightsize[x] = ~0;
+	gfs2_assert(sdp, sdp->sd_max_jheight <= GFS2_MAX_META_HEIGHT);
+
+	return 0;
+}
+
+static int init_names(struct gfs2_sbd *sdp, int silent)
+{
+	char *proto, *table;
+	int error = 0;
+
+	proto = sdp->sd_args.ar_lockproto;
+	table = sdp->sd_args.ar_locktable;
+
+	/*  Try to autodetect  */
+
+	if (!proto[0] || !table[0]) {
+		error = gfs2_read_super(sdp, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift, silent);
+		if (error)
+			return error;
+
+		if (!proto[0])
+			proto = sdp->sd_sb.sb_lockproto;
+		if (!table[0])
+			table = sdp->sd_sb.sb_locktable;
+	}
+
+	if (!table[0])
+		table = sdp->sd_vfs->s_id;
+
+	strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
+	strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
+
+	table = sdp->sd_table_name;
+	while ((table = strchr(table, '/')))
+		*table = '_';
+
+	return error;
+}
+
+static int init_locking(struct gfs2_sbd *sdp, struct gfs2_holder *mount_gh,
+			int undo)
+{
+	int error = 0;
+
+	if (undo)
+		goto fail_trans;
+
+	error = gfs2_glock_nq_num(sdp,
+				  GFS2_MOUNT_LOCK, &gfs2_nondisk_glops,
+				  LM_ST_EXCLUSIVE, LM_FLAG_NOEXP | GL_NOCACHE,
+				  mount_gh);
+	if (error) {
+		fs_err(sdp, "can't acquire mount glock: %d\n", error);
+		goto fail;
+	}
+
+	error = gfs2_glock_nq_num(sdp,
+				  GFS2_LIVE_LOCK, &gfs2_nondisk_glops,
+				  LM_ST_SHARED,
+				  LM_FLAG_NOEXP | GL_EXACT,
+				  &sdp->sd_live_gh);
+	if (error) {
+		fs_err(sdp, "can't acquire live glock: %d\n", error);
+		goto fail_mount;
+	}
+
+	error = gfs2_glock_get(sdp, GFS2_RENAME_LOCK, &gfs2_nondisk_glops,
+			       CREATE, &sdp->sd_rename_gl);
+	if (error) {
+		fs_err(sdp, "can't create rename glock: %d\n", error);
+		goto fail_live;
+	}
+
+	error = gfs2_glock_get(sdp, GFS2_FREEZE_LOCK, &gfs2_freeze_glops,
+			       CREATE, &sdp->sd_freeze_gl);
+	if (error) {
+		fs_err(sdp, "can't create transaction glock: %d\n", error);
+		goto fail_rename;
+	}
+
+	return 0;
+
+fail_trans:
+	gfs2_glock_put(sdp->sd_freeze_gl);
+fail_rename:
+	gfs2_glock_put(sdp->sd_rename_gl);
+fail_live:
+	gfs2_glock_dq_uninit(&sdp->sd_live_gh);
+fail_mount:
+	gfs2_glock_dq_uninit(mount_gh);
+fail:
+	return error;
+}
+
+static int gfs2_lookup_root(struct super_block *sb, struct dentry **dptr,
+			    u64 no_addr, const char *name)
+{
+	struct gfs2_sbd *sdp = sb->s_fs_info;
+	struct dentry *dentry;
+	struct inode *inode;
+
+	inode = gfs2_inode_lookup(sb, DT_DIR, no_addr, 0, 0);
+	if (IS_ERR(inode)) {
+		fs_err(sdp, "can't read in %s inode: %ld\n", name, PTR_ERR(inode));
+		return PTR_ERR(inode);
+	}
+	dentry = d_make_root(inode);
+	if (!dentry) {
+		fs_err(sdp, "can't alloc %s dentry\n", name);
+		return -ENOMEM;
+	}
+	*dptr = dentry;
+	return 0;
+}
+
+static int init_sb(struct gfs2_sbd *sdp, int silent)
+{
+	struct super_block *sb = sdp->sd_vfs;
+	struct gfs2_holder sb_gh;
+	u64 no_addr;
+	int ret;
+
+	ret = gfs2_glock_nq_num(sdp, GFS2_SB_LOCK, &gfs2_meta_glops,
+				LM_ST_SHARED, 0, &sb_gh);
+	if (ret) {
+		fs_err(sdp, "can't acquire superblock glock: %d\n", ret);
+		return ret;
+	}
+
+	ret = gfs2_read_sb(sdp, silent);
+	if (ret) {
+		fs_err(sdp, "can't read superblock: %d\n", ret);
+		goto out;
+	}
+
+	/* Set up the buffer cache and SB for real */
+	if (sdp->sd_sb.sb_bsize < bdev_logical_block_size(sb->s_bdev)) {
+		ret = -EINVAL;
+		fs_err(sdp, "FS block size (%u) is too small for device "
+		       "block size (%u)\n",
+		       sdp->sd_sb.sb_bsize, bdev_logical_block_size(sb->s_bdev));
+		goto out;
+	}
+	if (sdp->sd_sb.sb_bsize > PAGE_SIZE) {
+		ret = -EINVAL;
+		fs_err(sdp, "FS block size (%u) is too big for machine "
+		       "page size (%u)\n",
+		       sdp->sd_sb.sb_bsize, (unsigned int)PAGE_SIZE);
+		goto out;
+	}
+	sb_set_blocksize(sb, sdp->sd_sb.sb_bsize);
+
+	/* Get the root inode */
+	no_addr = sdp->sd_sb.sb_root_dir.no_addr;
+	ret = gfs2_lookup_root(sb, &sdp->sd_root_dir, no_addr, "root");
+	if (ret)
+		goto out;
+
+	/* Get the master inode */
+	no_addr = sdp->sd_sb.sb_master_dir.no_addr;
+	ret = gfs2_lookup_root(sb, &sdp->sd_master_dir, no_addr, "master");
+	if (ret) {
+		dput(sdp->sd_root_dir);
+		goto out;
+	}
+	sb->s_root = dget(sdp->sd_args.ar_meta ? sdp->sd_master_dir : sdp->sd_root_dir);
+out:
+	gfs2_glock_dq_uninit(&sb_gh);
+	return ret;
+}
+
+static void gfs2_others_may_mount(struct gfs2_sbd *sdp)
+{
+	char *message = "FIRSTMOUNT=Done";
+	char *envp[] = { message, NULL };
+
+	fs_info(sdp, "first mount done, others may mount\n");
+
+	if (sdp->sd_lockstruct.ls_ops->lm_first_done)
+		sdp->sd_lockstruct.ls_ops->lm_first_done(sdp);
+
+	kobject_uevent_env(&sdp->sd_kobj, KOBJ_CHANGE, envp);
+}
+
+/**
+ * gfs2_jindex_hold - Grab a lock on the jindex
+ * @sdp: The GFS2 superblock
+ * @ji_gh: the holder for the jindex glock
+ *
+ * Returns: errno
+ */
+
+static int gfs2_jindex_hold(struct gfs2_sbd *sdp, struct gfs2_holder *ji_gh)
+{
+	struct gfs2_inode *dip = GFS2_I(sdp->sd_jindex);
+	struct qstr name;
+	char buf[20];
+	struct gfs2_jdesc *jd;
+	int error;
+
+	name.name = buf;
+
+	mutex_lock(&sdp->sd_jindex_mutex);
+
+	for (;;) {
+		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, ji_gh);
+		if (error)
+			break;
+
+		name.len = sprintf(buf, "journal%u", sdp->sd_journals);
+		name.hash = gfs2_disk_hash(name.name, name.len);
+
+		error = gfs2_dir_check(sdp->sd_jindex, &name, NULL);
+		if (error == -ENOENT) {
+			error = 0;
+			break;
+		}
+
+		gfs2_glock_dq_uninit(ji_gh);
+
+		if (error)
+			break;
+
+		error = -ENOMEM;
+		jd = kzalloc(sizeof(struct gfs2_jdesc), GFP_KERNEL);
+		if (!jd)
+			break;
+
+		INIT_LIST_HEAD(&jd->extent_list);
+		INIT_LIST_HEAD(&jd->jd_revoke_list);
+
+		INIT_WORK(&jd->jd_work, gfs2_recover_func);
+		jd->jd_inode = gfs2_lookupi(sdp->sd_jindex, &name, 1);
+		if (!jd->jd_inode || IS_ERR(jd->jd_inode)) {
+			if (!jd->jd_inode)
+				error = -ENOENT;
+			else
+				error = PTR_ERR(jd->jd_inode);
+			kfree(jd);
+			break;
+		}
+
+		spin_lock(&sdp->sd_jindex_spin);
+		jd->jd_jid = sdp->sd_journals++;
+		list_add_tail(&jd->jd_list, &sdp->sd_jindex_list);
+		spin_unlock(&sdp->sd_jindex_spin);
+	}
+
+	mutex_unlock(&sdp->sd_jindex_mutex);
+
+	return error;
+}
+
+/**
+ * check_journal_clean - Make sure a journal is clean for a spectator mount
+ * @sdp: The GFS2 superblock
+ * @jd: The journal descriptor
+ *
+ * Returns: 0 if the journal is clean or locked, else an error
+ */
+static int check_journal_clean(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd)
+{
+	int error;
+	struct gfs2_holder j_gh;
+	struct gfs2_log_header_host head;
+	struct gfs2_inode *ip;
+
+	ip = GFS2_I(jd->jd_inode);
+	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_NOEXP |
+				   GL_EXACT | GL_NOCACHE, &j_gh);
+	if (error) {
+		fs_err(sdp, "Error locking journal for spectator mount.\n");
+		return -EPERM;
+	}
+	error = gfs2_jdesc_check(jd);
+	if (error) {
+		fs_err(sdp, "Error checking journal for spectator mount.\n");
+		goto out_unlock;
+	}
+	error = gfs2_find_jhead(jd, &head);
+	if (error) {
+		fs_err(sdp, "Error parsing journal for spectator mount.\n");
+		goto out_unlock;
+	}
+	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
+		error = -EPERM;
+		fs_err(sdp, "jid=%u: Journal is dirty, so the first mounter "
+		       "must not be a spectator.\n", jd->jd_jid);
+	}
+
+out_unlock:
+	gfs2_glock_dq_uninit(&j_gh);
+	return error;
+}
+
+static int init_journal(struct gfs2_sbd *sdp, int undo)
+{
+	struct inode *master = d_inode(sdp->sd_master_dir);
+	struct gfs2_holder ji_gh;
+	struct gfs2_inode *ip;
+	int jindex = 1;
+	int error = 0;
+
+	if (undo) {
+		jindex = 0;
+		goto fail_jinode_gh;
+	}
+
+	sdp->sd_jindex = gfs2_lookup_simple(master, "jindex");
+	if (IS_ERR(sdp->sd_jindex)) {
+		fs_err(sdp, "can't lookup journal index: %d\n", error);
+		return PTR_ERR(sdp->sd_jindex);
+	}
+
+	/* Load in the journal index special file */
+
+	error = gfs2_jindex_hold(sdp, &ji_gh);
+	if (error) {
+		fs_err(sdp, "can't read journal index: %d\n", error);
+		goto fail;
+	}
+
+	error = -EUSERS;
+	if (!gfs2_jindex_size(sdp)) {
+		fs_err(sdp, "no journals!\n");
+		goto fail_jindex;
+	}
+
+	if (sdp->sd_args.ar_spectator) {
+		sdp->sd_jdesc = gfs2_jdesc_find(sdp, 0);
+		atomic_set(&sdp->sd_log_blks_free, sdp->sd_jdesc->jd_blocks);
+		atomic_set(&sdp->sd_log_thresh1, 2*sdp->sd_jdesc->jd_blocks/5);
+		atomic_set(&sdp->sd_log_thresh2, 4*sdp->sd_jdesc->jd_blocks/5);
+	} else {
+		if (sdp->sd_lockstruct.ls_jid >= gfs2_jindex_size(sdp)) {
+			fs_err(sdp, "can't mount journal #%u\n",
+			       sdp->sd_lockstruct.ls_jid);
+			fs_err(sdp, "there are only %u journals (0 - %u)\n",
+			       gfs2_jindex_size(sdp),
+			       gfs2_jindex_size(sdp) - 1);
+			goto fail_jindex;
+		}
+		sdp->sd_jdesc = gfs2_jdesc_find(sdp, sdp->sd_lockstruct.ls_jid);
+
+		error = gfs2_glock_nq_num(sdp, sdp->sd_lockstruct.ls_jid,
+					  &gfs2_journal_glops,
+					  LM_ST_EXCLUSIVE, LM_FLAG_NOEXP,
+					  &sdp->sd_journal_gh);
+		if (error) {
+			fs_err(sdp, "can't acquire journal glock: %d\n", error);
+			goto fail_jindex;
+		}
+
+		ip = GFS2_I(sdp->sd_jdesc->jd_inode);
+		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
+					   LM_FLAG_NOEXP | GL_EXACT | GL_NOCACHE,
+					   &sdp->sd_jinode_gh);
+		if (error) {
+			fs_err(sdp, "can't acquire journal inode glock: %d\n",
+			       error);
+			goto fail_journal_gh;
+		}
+
+		error = gfs2_jdesc_check(sdp->sd_jdesc);
+		if (error) {
+			fs_err(sdp, "my journal (%u) is bad: %d\n",
+			       sdp->sd_jdesc->jd_jid, error);
+			goto fail_jinode_gh;
+		}
+		atomic_set(&sdp->sd_log_blks_free, sdp->sd_jdesc->jd_blocks);
+		atomic_set(&sdp->sd_log_thresh1, 2*sdp->sd_jdesc->jd_blocks/5);
+		atomic_set(&sdp->sd_log_thresh2, 4*sdp->sd_jdesc->jd_blocks/5);
+
+		/* Map the extents for this journal's blocks */
+		gfs2_map_journal_extents(sdp, sdp->sd_jdesc);
+	}
+	trace_gfs2_log_blocks(sdp, atomic_read(&sdp->sd_log_blks_free));
+
+	if (sdp->sd_lockstruct.ls_first) {
+		unsigned int x;
+		for (x = 0; x < sdp->sd_journals; x++) {
+			struct gfs2_jdesc *jd = gfs2_jdesc_find(sdp, x);
+
+			if (sdp->sd_args.ar_spectator) {
+				error = check_journal_clean(sdp, jd);
+				if (error)
+					goto fail_jinode_gh;
+				continue;
+			}
+			error = gfs2_recover_journal(jd, true);
+			if (error) {
+				fs_err(sdp, "error recovering journal %u: %d\n",
+				       x, error);
+				goto fail_jinode_gh;
+			}
+		}
+
+		gfs2_others_may_mount(sdp);
+	} else if (!sdp->sd_args.ar_spectator) {
+		error = gfs2_recover_journal(sdp->sd_jdesc, true);
+		if (error) {
+			fs_err(sdp, "error recovering my journal: %d\n", error);
+			goto fail_jinode_gh;
+		}
+	}
+
+	set_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags);
+	gfs2_glock_dq_uninit(&ji_gh);
+	jindex = 0;
+	INIT_WORK(&sdp->sd_freeze_work, gfs2_freeze_func);
+	return 0;
+
+fail_jinode_gh:
+	if (!sdp->sd_args.ar_spectator)
+		gfs2_glock_dq_uninit(&sdp->sd_jinode_gh);
+fail_journal_gh:
+	if (!sdp->sd_args.ar_spectator)
+		gfs2_glock_dq_uninit(&sdp->sd_journal_gh);
+fail_jindex:
+	gfs2_jindex_free(sdp);
+	if (jindex)
+		gfs2_glock_dq_uninit(&ji_gh);
+fail:
+	iput(sdp->sd_jindex);
+	return error;
+}
+
+static struct lock_class_key gfs2_quota_imutex_key;
+
+static int init_inodes(struct gfs2_sbd *sdp, int undo)
+{
+	int error = 0;
+	struct inode *master = d_inode(sdp->sd_master_dir);
+
+	if (undo)
+		goto fail_qinode;
+
+	error = init_journal(sdp, undo);
+	complete_all(&sdp->sd_journal_ready);
+	if (error)
+		goto fail;
+
+	/* Read in the master statfs inode */
+	sdp->sd_statfs_inode = gfs2_lookup_simple(master, "statfs");
+	if (IS_ERR(sdp->sd_statfs_inode)) {
+		error = PTR_ERR(sdp->sd_statfs_inode);
+		fs_err(sdp, "can't read in statfs inode: %d\n", error);
+		goto fail_journal;
+	}
+
+	/* Read in the resource index inode */
+	sdp->sd_rindex = gfs2_lookup_simple(master, "rindex");
+	if (IS_ERR(sdp->sd_rindex)) {
+		error = PTR_ERR(sdp->sd_rindex);
+		fs_err(sdp, "can't get resource index inode: %d\n", error);
+		goto fail_statfs;
+	}
+	sdp->sd_rindex_uptodate = 0;
+
+	/* Read in the quota inode */
+	sdp->sd_quota_inode = gfs2_lookup_simple(master, "quota");
+	if (IS_ERR(sdp->sd_quota_inode)) {
+		error = PTR_ERR(sdp->sd_quota_inode);
+		fs_err(sdp, "can't get quota file inode: %d\n", error);
+		goto fail_rindex;
+	}
+	/*
+	 * i_mutex on quota files is special. Since this inode is hidden system
+	 * file, we are safe to define locking ourselves.
+	 */
+	lockdep_set_class(&sdp->sd_quota_inode->i_mutex,
+			  &gfs2_quota_imutex_key);
+
+	error = gfs2_rindex_update(sdp);
+	if (error)
+		goto fail_qinode;
+
+	return 0;
+
+fail_qinode:
+	iput(sdp->sd_quota_inode);
+fail_rindex:
+	gfs2_clear_rgrpd(sdp);
+	iput(sdp->sd_rindex);
+fail_statfs:
+	iput(sdp->sd_statfs_inode);
+fail_journal:
+	init_journal(sdp, UNDO);
+fail:
+	return error;
+}
+
+static int init_per_node(struct gfs2_sbd *sdp, int undo)
+{
+	struct inode *pn = NULL;
+	char buf[30];
+	int error = 0;
+	struct gfs2_inode *ip;
+	struct inode *master = d_inode(sdp->sd_master_dir);
+
+	if (sdp->sd_args.ar_spectator)
+		return 0;
+
+	if (undo)
+		goto fail_qc_gh;
+
+	pn = gfs2_lookup_simple(master, "per_node");
+	if (IS_ERR(pn)) {
+		error = PTR_ERR(pn);
+		fs_err(sdp, "can't find per_node directory: %d\n", error);
+		return error;
+	}
+
+	sprintf(buf, "statfs_change%u", sdp->sd_jdesc->jd_jid);
+	sdp->sd_sc_inode = gfs2_lookup_simple(pn, buf);
+	if (IS_ERR(sdp->sd_sc_inode)) {
+		error = PTR_ERR(sdp->sd_sc_inode);
+		fs_err(sdp, "can't find local \"sc\" file: %d\n", error);
+		goto fail;
+	}
+
+	sprintf(buf, "quota_change%u", sdp->sd_jdesc->jd_jid);
+	sdp->sd_qc_inode = gfs2_lookup_simple(pn, buf);
+	if (IS_ERR(sdp->sd_qc_inode)) {
+		error = PTR_ERR(sdp->sd_qc_inode);
+		fs_err(sdp, "can't find local \"qc\" file: %d\n", error);
+		goto fail_ut_i;
+	}
+
+	iput(pn);
+	pn = NULL;
+
+	ip = GFS2_I(sdp->sd_sc_inode);
+	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0,
+				   &sdp->sd_sc_gh);
+	if (error) {
+		fs_err(sdp, "can't lock local \"sc\" file: %d\n", error);
+		goto fail_qc_i;
+	}
+
+	ip = GFS2_I(sdp->sd_qc_inode);
+	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0,
+				   &sdp->sd_qc_gh);
+	if (error) {
+		fs_err(sdp, "can't lock local \"qc\" file: %d\n", error);
+		goto fail_ut_gh;
+	}
+
+	return 0;
+
+fail_qc_gh:
+	gfs2_glock_dq_uninit(&sdp->sd_qc_gh);
+fail_ut_gh:
+	gfs2_glock_dq_uninit(&sdp->sd_sc_gh);
+fail_qc_i:
+	iput(sdp->sd_qc_inode);
+fail_ut_i:
+	iput(sdp->sd_sc_inode);
+fail:
+	if (pn)
+		iput(pn);
+	return error;
+}
+
+static const match_table_t nolock_tokens = {
+	{ Opt_jid, "jid=%d\n", },
+	{ Opt_err, NULL },
+};
+
+static const struct lm_lockops nolock_ops = {
+	.lm_proto_name = "lock_nolock",
+	.lm_put_lock = gfs2_glock_free,
+	.lm_tokens = &nolock_tokens,
+};
+
+/**
+ * gfs2_lm_mount - mount a locking protocol
+ * @sdp: the filesystem
+ * @args: mount arguments
+ * @silent: if 1, don't complain if the FS isn't a GFS2 fs
+ *
+ * Returns: errno
+ */
+
+static int gfs2_lm_mount(struct gfs2_sbd *sdp, int silent)
+{
+	const struct lm_lockops *lm;
+	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
+	struct gfs2_args *args = &sdp->sd_args;
+	const char *proto = sdp->sd_proto_name;
+	const char *table = sdp->sd_table_name;
+	char *o, *options;
+	int ret;
+
+	if (!strcmp("lock_nolock", proto)) {
+		lm = &nolock_ops;
+		sdp->sd_args.ar_localflocks = 1;
+#ifdef CONFIG_GFS2_FS_LOCKING_DLM
+	} else if (!strcmp("lock_dlm", proto)) {
+		lm = &gfs2_dlm_ops;
+#endif
+	} else {
+		pr_info("can't find protocol %s\n", proto);
+		return -ENOENT;
+	}
+
+	fs_info(sdp, "Trying to join cluster \"%s\", \"%s\"\n", proto, table);
+
+	ls->ls_ops = lm;
+	ls->ls_first = 1;
+
+	for (options = args->ar_hostdata; (o = strsep(&options, ":")); ) {
+		substring_t tmp[MAX_OPT_ARGS];
+		int token, option;
+
+		if (!o || !*o)
+			continue;
+
+		token = match_token(o, *lm->lm_tokens, tmp);
+		switch (token) {
+		case Opt_jid:
+			ret = match_int(&tmp[0], &option);
+			if (ret || option < 0) 
+				goto hostdata_error;
+			if (test_and_clear_bit(SDF_NOJOURNALID, &sdp->sd_flags))
+				ls->ls_jid = option;
+			break;
+		case Opt_id:
+		case Opt_nodir:
+			/* Obsolete, but left for backward compat purposes */
+			break;
+		case Opt_first:
+			ret = match_int(&tmp[0], &option);
+			if (ret || (option != 0 && option != 1))
+				goto hostdata_error;
+			ls->ls_first = option;
+			break;
+		case Opt_err:
+		default:
+hostdata_error:
+			fs_info(sdp, "unknown hostdata (%s)\n", o);
+			return -EINVAL;
+		}
+	}
+
+	if (lm->lm_mount == NULL) {
+		fs_info(sdp, "Now mounting FS...\n");
+		complete_all(&sdp->sd_locking_init);
+		return 0;
+	}
+	ret = lm->lm_mount(sdp, table);
+	if (ret == 0)
+		fs_info(sdp, "Joined cluster. Now mounting FS...\n");
+	complete_all(&sdp->sd_locking_init);
+	return ret;
+}
+
+void gfs2_lm_unmount(struct gfs2_sbd *sdp)
+{
+	const struct lm_lockops *lm = sdp->sd_lockstruct.ls_ops;
+	if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) &&
+	    lm->lm_unmount)
+		lm->lm_unmount(sdp);
+}
+
+static int wait_on_journal(struct gfs2_sbd *sdp)
+{
+	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
+		return 0;
+
+	return wait_on_bit(&sdp->sd_flags, SDF_NOJOURNALID, TASK_INTERRUPTIBLE)
+		? -EINTR : 0;
+}
+
+void gfs2_online_uevent(struct gfs2_sbd *sdp)
+{
+	struct super_block *sb = sdp->sd_vfs;
+	char ro[20];
+	char spectator[20];
+	char *envp[] = { ro, spectator, NULL };
+	sprintf(ro, "RDONLY=%d", (sb->s_flags & MS_RDONLY) ? 1 : 0);
+	sprintf(spectator, "SPECTATOR=%d", sdp->sd_args.ar_spectator ? 1 : 0);
+	kobject_uevent_env(&sdp->sd_kobj, KOBJ_ONLINE, envp);
+}
+
+/**
+ * fill_super - Read in superblock
+ * @sb: The VFS superblock
+ * @data: Mount options
+ * @silent: Don't complain if it's not a GFS2 filesystem
+ *
+ * Returns: errno
+ */
+
+static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent)
+{
+	struct gfs2_sbd *sdp;
+	struct gfs2_holder mount_gh;
+	int error;
+
+	sdp = init_sbd(sb);
+	if (!sdp) {
+		pr_warn("can't alloc struct gfs2_sbd\n");
+		return -ENOMEM;
+	}
+	sdp->sd_args = *args;
+
+	if (sdp->sd_args.ar_spectator) {
+                sb->s_flags |= MS_RDONLY;
+		set_bit(SDF_RORECOVERY, &sdp->sd_flags);
+	}
+	if (sdp->sd_args.ar_posix_acl)
+		sb->s_flags |= MS_POSIXACL;
+	if (sdp->sd_args.ar_nobarrier)
+		set_bit(SDF_NOBARRIERS, &sdp->sd_flags);
+
+	sb->s_flags |= MS_NOSEC;
+	sb->s_magic = GFS2_MAGIC;
+	sb->s_op = &gfs2_super_ops;
+	sb->s_d_op = &gfs2_dops;
+	sb->s_export_op = &gfs2_export_ops;
+	sb->s_xattr = gfs2_xattr_handlers;
+	sb->s_qcop = &gfs2_quotactl_ops;
+	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
+	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
+	sb->s_time_gran = 1;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+
+	/* Set up the buffer cache and fill in some fake block size values
+	   to allow us to read-in the on-disk superblock. */
+	sdp->sd_sb.sb_bsize = sb_min_blocksize(sb, GFS2_BASIC_BLOCK);
+	sdp->sd_sb.sb_bsize_shift = sb->s_blocksize_bits;
+	sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -
+                               GFS2_BASIC_BLOCK_SHIFT;
+	sdp->sd_fsb2bb = 1 << sdp->sd_fsb2bb_shift;
+
+	sdp->sd_tune.gt_logd_secs = sdp->sd_args.ar_commit;
+	sdp->sd_tune.gt_quota_quantum = sdp->sd_args.ar_quota_quantum;
+	if (sdp->sd_args.ar_statfs_quantum) {
+		sdp->sd_tune.gt_statfs_slow = 0;
+		sdp->sd_tune.gt_statfs_quantum = sdp->sd_args.ar_statfs_quantum;
+	} else {
+		sdp->sd_tune.gt_statfs_slow = 1;
+		sdp->sd_tune.gt_statfs_quantum = 30;
+	}
+
+	error = init_names(sdp, silent);
+	if (error) {
+		/* In this case, we haven't initialized sysfs, so we have to
+		   manually free the sdp. */
+		free_percpu(sdp->sd_lkstats);
+		kfree(sdp);
+		sb->s_fs_info = NULL;
+		return error;
+	}
+
+	snprintf(sdp->sd_fsname, GFS2_FSNAME_LEN, "%s", sdp->sd_table_name);
+
+	error = gfs2_sys_fs_add(sdp);
+	/*
+	 * If we hit an error here, gfs2_sys_fs_add will have called function
+	 * kobject_put which causes the sysfs usage count to go to zero, which
+	 * causes sysfs to call function gfs2_sbd_release, which frees sdp.
+	 * Subsequent error paths here will call gfs2_sys_fs_del, which also
+	 * kobject_put to free sdp.
+	 */
+	if (error)
+		return error;
+
+	gfs2_create_debugfs_file(sdp);
+
+	error = gfs2_lm_mount(sdp, silent);
+	if (error)
+		goto fail_debug;
+
+	error = init_locking(sdp, &mount_gh, DO);
+	if (error)
+		goto fail_lm;
+
+	error = init_sb(sdp, silent);
+	if (error)
+		goto fail_locking;
+
+	error = wait_on_journal(sdp);
+	if (error)
+		goto fail_sb;
+
+	/*
+	 * If user space has failed to join the cluster or some similar
+	 * failure has occurred, then the journal id will contain a
+	 * negative (error) number. This will then be returned to the
+	 * caller (of the mount syscall). We do this even for spectator
+	 * mounts (which just write a jid of 0 to indicate "ok" even though
+	 * the jid is unused in the spectator case)
+	 */
+	if (sdp->sd_lockstruct.ls_jid < 0) {
+		error = sdp->sd_lockstruct.ls_jid;
+		sdp->sd_lockstruct.ls_jid = 0;
+		goto fail_sb;
+	}
+
+	if (sdp->sd_args.ar_spectator)
+		snprintf(sdp->sd_fsname, GFS2_FSNAME_LEN, "%s.s",
+			 sdp->sd_table_name);
+	else
+		snprintf(sdp->sd_fsname, GFS2_FSNAME_LEN, "%s.%u",
+			 sdp->sd_table_name, sdp->sd_lockstruct.ls_jid);
+
+	error = init_inodes(sdp, DO);
+	if (error)
+		goto fail_sb;
+
+	error = init_per_node(sdp, DO);
+	if (error)
+		goto fail_inodes;
+
+	error = gfs2_statfs_init(sdp);
+	if (error) {
+		fs_err(sdp, "can't initialize statfs subsystem: %d\n", error);
+		goto fail_per_node;
+	}
+
+	if (!(sb->s_flags & MS_RDONLY)) {
+		error = gfs2_make_fs_rw(sdp);
+		if (error) {
+			fs_err(sdp, "can't make FS RW: %d\n", error);
+			goto fail_per_node;
+		}
+	}
+
+	gfs2_glock_dq_uninit(&mount_gh);
+	gfs2_online_uevent(sdp);
+	return 0;
+
+fail_per_node:
+	init_per_node(sdp, UNDO);
+fail_inodes:
+	init_inodes(sdp, UNDO);
+fail_sb:
+	if (sdp->sd_root_dir)
+		dput(sdp->sd_root_dir);
+	if (sdp->sd_master_dir)
+		dput(sdp->sd_master_dir);
+	if (sb->s_root)
+		dput(sb->s_root);
+	sb->s_root = NULL;
+fail_locking:
+	init_locking(sdp, &mount_gh, UNDO);
+fail_lm:
+	complete_all(&sdp->sd_journal_ready);
+	gfs2_gl_hash_clear(sdp);
+	gfs2_lm_unmount(sdp);
+fail_debug:
+	gfs2_delete_debugfs_file(sdp);
+	free_percpu(sdp->sd_lkstats);
+	/* gfs2_sys_fs_del must be the last thing we do, since it causes
+	 * sysfs to call function gfs2_sbd_release, which frees sdp. */
+	gfs2_sys_fs_del(sdp);
+	sb->s_fs_info = NULL;
+	return error;
+}
+
+static int set_gfs2_super(struct super_block *s, void *data)
+{
+	s->s_bdev = data;
+	s->s_dev = s->s_bdev->bd_dev;
+
+	/*
+	 * We set the bdi here to the queue backing, file systems can
+	 * overwrite this in ->fill_super()
+	 */
+	s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
+	return 0;
+}
+
+static int test_gfs2_super(struct super_block *s, void *ptr)
+{
+	struct block_device *bdev = ptr;
+	return (bdev == s->s_bdev);
+}
+
+/**
+ * gfs2_mount - Get the GFS2 superblock
+ * @fs_type: The GFS2 filesystem type
+ * @flags: Mount flags
+ * @dev_name: The name of the device
+ * @data: The mount arguments
+ *
+ * Q. Why not use get_sb_bdev() ?
+ * A. We need to select one of two root directories to mount, independent
+ *    of whether this is the initial, or subsequent, mount of this sb
+ *
+ * Returns: 0 or -ve on error
+ */
+
+static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
+		       const char *dev_name, void *data)
+{
+	struct block_device *bdev;
+	struct super_block *s;
+	fmode_t mode = FMODE_READ | FMODE_EXCL;
+	int error;
+	struct gfs2_args args;
+	struct gfs2_sbd *sdp;
+
+	if (!(flags & MS_RDONLY))
+		mode |= FMODE_WRITE;
+
+	bdev = blkdev_get_by_path(dev_name, mode, fs_type);
+	if (IS_ERR(bdev))
+		return ERR_CAST(bdev);
+
+	/*
+	 * once the super is inserted into the list by sget, s_umount
+	 * will protect the lockfs code from trying to start a snapshot
+	 * while we are mounting
+	 */
+	mutex_lock(&bdev->bd_fsfreeze_mutex);
+	if (bdev->bd_fsfreeze_count > 0) {
+		mutex_unlock(&bdev->bd_fsfreeze_mutex);
+		error = -EBUSY;
+		goto error_bdev;
+	}
+	s = sget(fs_type, test_gfs2_super, set_gfs2_super, flags, bdev);
+	mutex_unlock(&bdev->bd_fsfreeze_mutex);
+	error = PTR_ERR(s);
+	if (IS_ERR(s))
+		goto error_bdev;
+
+	if (s->s_root) {
+		/*
+		 * s_umount nests inside bd_mutex during
+		 * __invalidate_device().  blkdev_put() acquires
+		 * bd_mutex and can't be called under s_umount.  Drop
+		 * s_umount temporarily.  This is safe as we're
+		 * holding an active reference.
+		 */
+		up_write(&s->s_umount);
+		blkdev_put(bdev, mode);
+		down_write(&s->s_umount);
+	}
+
+	memset(&args, 0, sizeof(args));
+	args.ar_quota = GFS2_QUOTA_DEFAULT;
+	args.ar_data = GFS2_DATA_DEFAULT;
+	args.ar_commit = 30;
+	args.ar_statfs_quantum = 30;
+	args.ar_quota_quantum = 60;
+	args.ar_errors = GFS2_ERRORS_DEFAULT;
+
+	error = gfs2_mount_args(&args, data);
+	if (error) {
+		pr_warn("can't parse mount arguments\n");
+		goto error_super;
+	}
+
+	if (s->s_root) {
+		error = -EBUSY;
+		if ((flags ^ s->s_flags) & MS_RDONLY)
+			goto error_super;
+	} else {
+		char b[BDEVNAME_SIZE];
+
+		s->s_mode = mode;
+		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
+		sb_set_blocksize(s, block_size(bdev));
+		error = fill_super(s, &args, flags & MS_SILENT ? 1 : 0);
+		if (error)
+			goto error_super;
+		s->s_flags |= MS_ACTIVE;
+		bdev->bd_super = s;
+	}
+
+	sdp = s->s_fs_info;
+	if (args.ar_meta)
+		return dget(sdp->sd_master_dir);
+	else
+		return dget(sdp->sd_root_dir);
+
+error_super:
+	deactivate_locked_super(s);
+	return ERR_PTR(error);
+error_bdev:
+	blkdev_put(bdev, mode);
+	return ERR_PTR(error);
+}
+
+static int set_meta_super(struct super_block *s, void *ptr)
+{
+	return -EINVAL;
+}
+
+static struct dentry *gfs2_mount_meta(struct file_system_type *fs_type,
+			int flags, const char *dev_name, void *data)
+{
+	struct super_block *s;
+	struct gfs2_sbd *sdp;
+	struct path path;
+	int error;
+
+	error = kern_path(dev_name, LOOKUP_FOLLOW, &path);
+	if (error) {
+		pr_warn("path_lookup on %s returned error %d\n",
+			dev_name, error);
+		return ERR_PTR(error);
+	}
+	s = sget(&gfs2_fs_type, test_gfs2_super, set_meta_super, flags,
+		 d_inode(path.dentry)->i_sb->s_bdev);
+	path_put(&path);
+	if (IS_ERR(s)) {
+		pr_warn("gfs2 mount does not exist\n");
+		return ERR_CAST(s);
+	}
+	if ((flags ^ s->s_flags) & MS_RDONLY) {
+		deactivate_locked_super(s);
+		return ERR_PTR(-EBUSY);
+	}
+	sdp = s->s_fs_info;
+	return dget(sdp->sd_master_dir);
+}
+
+static void gfs2_kill_sb(struct super_block *sb)
+{
+	struct gfs2_sbd *sdp = sb->s_fs_info;
+
+	if (sdp == NULL) {
+		kill_block_super(sb);
+		return;
+	}
+
+	gfs2_log_flush(sdp, NULL, SYNC_FLUSH);
+	dput(sdp->sd_root_dir);
+	dput(sdp->sd_master_dir);
+	sdp->sd_root_dir = NULL;
+	sdp->sd_master_dir = NULL;
+	shrink_dcache_sb(sb);
+	gfs2_delete_debugfs_file(sdp);
+	free_percpu(sdp->sd_lkstats);
+	kill_block_super(sb);
+}
+
+struct file_system_type gfs2_fs_type = {
+	.name = "gfs2",
+	.fs_flags = FS_REQUIRES_DEV,
+	.mount = gfs2_mount,
+	.kill_sb = gfs2_kill_sb,
+	.owner = THIS_MODULE,
+};
+MODULE_ALIAS_FS("gfs2");
+
+struct file_system_type gfs2meta_fs_type = {
+	.name = "gfs2meta",
+	.fs_flags = FS_REQUIRES_DEV,
+	.mount = gfs2_mount_meta,
+	.owner = THIS_MODULE,
+};
+MODULE_ALIAS_FS("gfs2meta");