From: Jason Dillaman <dillaman@redhat.com>
Date: Mon, 9 Mar 2015 13:55:08 +0000 (-0400)
Subject: librbd: hold write snap_lock when refreshing object map
X-Git-Tag: v0.94~47^2~10
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=9dcd517ff9495ff917b83a761a03ec01cf9f2932;p=ceph.git

librbd: hold write snap_lock when refreshing object map

If the object map needs to be invalidated, a write lock on
snap_lock is required.

Fixes: #11067
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
---

diff --git a/src/librbd/ImageWatcher.cc b/src/librbd/ImageWatcher.cc
index d4aa428efe9a..142c2db84233 100644
--- a/src/librbd/ImageWatcher.cc
+++ b/src/librbd/ImageWatcher.cc
@@ -307,7 +307,7 @@ int ImageWatcher::lock() {
       unlock();
       return r;
     }
-    RWLock::RLocker l2(m_image_ctx.snap_lock);
+    RWLock::WLocker l2(m_image_ctx.snap_lock);
     m_image_ctx.object_map.refresh(CEPH_NOSNAP);
   }
 
diff --git a/src/librbd/ObjectMap.cc b/src/librbd/ObjectMap.cc
index 4aa3c3b65921..27d1db7a23d5 100644
--- a/src/librbd/ObjectMap.cc
+++ b/src/librbd/ObjectMap.cc
@@ -147,7 +147,7 @@ bool ObjectMap::object_may_exist(uint64_t object_no) const
 
 void ObjectMap::refresh(uint64_t snap_id)
 {
-  assert(m_image_ctx.snap_lock.is_locked());
+  assert(m_image_ctx.snap_lock.is_wlocked());
   RWLock::WLocker l(m_image_ctx.object_map_lock);
 
   uint64_t features;
@@ -173,10 +173,10 @@ void ObjectMap::refresh(uint64_t snap_id)
     m_object_map.clear();
     return;
   }
-  
+
   ldout(cct, 20) << "refreshed object map: " << m_object_map.size()
                  << dendl;
-  
+
   uint64_t num_objs = Striper::get_num_objects(
     m_image_ctx.layout, m_image_ctx.get_image_size(snap_id));
   if (m_object_map.size() != num_objs) {