From: Josh Durgin <jdurgin@redhat.com>
Date: Tue, 24 Feb 2015 03:50:55 +0000 (-0800)
Subject: librbd: take ImageCtx->snap_lock for write in add_snap()
X-Git-Tag: v0.93~6^2~12
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=04d360a4c1e7b29bafe4aa4a9e91e98360932d31;p=ceph.git

librbd: take ImageCtx->snap_lock for write in add_snap()

add_snap() updates the ImageCtx snapshot metadata in memory, as well
as reading the flags as part of the object map snapshot. Both of these
require holding snap_lock.

Signed-off-by: Josh Durgin <jdurgin@redhat.com>
---

diff --git a/src/librbd/internal.cc b/src/librbd/internal.cc
index 6db4eba4985..d3ee11696a5 100644
--- a/src/librbd/internal.cc
+++ b/src/librbd/internal.cc
@@ -1783,6 +1783,7 @@ reprotect_and_return_err:
       return r;
     }
 
+    RWLock::WLocker l(ictx->snap_lock);
     if (!ictx->old_format) {
       if (ictx->object_map != NULL) {
 	ictx->object_map->snapshot(snap_id);