diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-10-16 23:18:16 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-11-09 16:22:06 -0800 |
| commit | 651385e4bbbff823f111e4e8a68b2e1613c34c79 (patch) | |
| tree | fb4b3ed8702f2a78754c4f58e6174e9f6f13eb38 | |
| parent | e61f48eb0ac00c6d73dd53b3d79abe2c578328dc (diff) | |
dm snapshot: lock snapshot while supplying status
commit 4c6fff445d7aa753957856278d4d93bcad6e2c14 upstream.
This patch locks the snapshot when returning status. It fixes a race
when it could return an invalid number of free chunks if someone
was simultaneously modifying it.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/md/dm-snap.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 53f4063f7ea4..b9dd22ce47d4 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1147,6 +1147,8 @@ static int snapshot_status(struct dm_target *ti, status_type_t type, unsigned sz = 0; struct dm_snapshot *snap = ti->private; + down_write(&snap->lock); + switch (type) { case STATUSTYPE_INFO: if (!snap->valid) @@ -1178,6 +1180,8 @@ static int snapshot_status(struct dm_target *ti, status_type_t type, break; } + up_write(&snap->lock); + return 0; } |