ceph: shared persistent read-only rbd cache

This patch introduces introduces RBD shared persistent RO cache which
can provide client-side sharing cache for rbd clone/snapshot case.

Change-Id: Icad8063f4f10b1ab4ce31920e90d5affa7d0abdc
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
Signed-off-by: Dehao Shang <dehao.shang@intel.com>
Signed-off-by: Tushar Gohad <tushar.gohad@intel.com>
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
Signed-off-by: Yuan Zhou <yuan.zhou@intel.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/src/ceph/0003-librbd-fix-bufferlist-point.patch b/src/ceph/0003-librbd-fix-bufferlist-point.patch
new file mode 100644
index 0000000..b0030ea
--- /dev/null
+++ b/src/ceph/0003-librbd-fix-bufferlist-point.patch
@@ -0,0 +1,71 @@
+From 656b499b00fb237c83b8ccccc519a1577d981199 Mon Sep 17 00:00:00 2001
+From: Yuan Zhou <yuan.zhou@intel.com>
+Date: Mon, 6 Aug 2018 15:38:35 +0800
+Subject: [PATCH 03/10] librbd: fix bufferlist point
+
+Signed-off-by: Yuan Zhou <yuan.zhou@intel.com>
+---
+ src/tools/rbd_cache/ObjectCacheStore.cc | 10 +++++-----
+ src/tools/rbd_cache/ObjectCacheStore.h  |  2 +-
+ 2 files changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/src/tools/rbd_cache/ObjectCacheStore.cc b/src/tools/rbd_cache/ObjectCacheStore.cc
+index 9572a1a..2a87469 100644
+--- a/src/tools/rbd_cache/ObjectCacheStore.cc
++++ b/src/tools/rbd_cache/ObjectCacheStore.cc
+@@ -63,13 +63,13 @@ int ObjectCacheStore::do_promote(std::string pool_name, std::string object_name)
+     m_cache_table.emplace(cache_file_name, PROMOTING);
+   }
+ 
+-  librados::bufferlist read_buf;      
++  librados::bufferlist* read_buf = new librados::bufferlist();
+   int object_size = 4096*1024; //TODO(): read config from image metadata
+ 
+   //TODO(): async promote
+   ret = promote_object(ioctx, object_name, read_buf, object_size);
+   if (ret == -ENOENT) {
+-    read_buf.append(std::string(object_size, '0'));
++    read_buf->append(std::string(object_size, '0'));
+     ret = 0;
+   }
+ 
+@@ -81,7 +81,7 @@ int ObjectCacheStore::do_promote(std::string pool_name, std::string object_name)
+   // persistent to cache
+   librbd::cache::SyncFile cache_file(m_cct, cache_file_name);
+   cache_file.open();
+-  ret = cache_file.write_object_to_file(read_buf, object_size);
++  ret = cache_file.write_object_to_file(*read_buf, object_size);
+   
+   assert(m_cache_table.find(cache_file_name) != m_cache_table.end()); 
+ 
+@@ -132,12 +132,12 @@ int ObjectCacheStore::lock_cache(std::string vol_name) {
+   return 0;
+ }
+ 
+-int ObjectCacheStore::promote_object(librados::IoCtx* ioctx, std::string object_name, librados::bufferlist read_buf, uint64_t read_len) {
++int ObjectCacheStore::promote_object(librados::IoCtx* ioctx, std::string object_name, librados::bufferlist* read_buf, uint64_t read_len) {
+   int ret;
+ 
+   librados::AioCompletion* read_completion = librados::Rados::aio_create_completion(); 
+ 
+-  ret = ioctx->aio_read(object_name, read_completion, &read_buf, read_len, 0);
++  ret = ioctx->aio_read(object_name, read_completion, read_buf, read_len, 0);
+   if(ret < 0) {
+     lderr(m_cct) << "fail to read from rados" << dendl;
+     return ret;
+diff --git a/src/tools/rbd_cache/ObjectCacheStore.h b/src/tools/rbd_cache/ObjectCacheStore.h
+index a81beea..db09efa 100644
+--- a/src/tools/rbd_cache/ObjectCacheStore.h
++++ b/src/tools/rbd_cache/ObjectCacheStore.h
+@@ -45,7 +45,7 @@ class ObjectCacheStore
+     int do_promote(std::string pool_name, std::string object_name);
+ 
+     int promote_object(librados::IoCtx*, std::string object_name,
+-                       librados::bufferlist read_buf,
++                       librados::bufferlist* read_buf,
+                        uint64_t length);
+ 
+     enum {
+-- 
+2.7.4
+