rbd: protect read of snapshot sequence number

This is updated whenever a snapshot is added or deleted, and the
snapc pointer is changed with every refresh of the header.

Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: Alex Elder <elder@dreamhost.com>
Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
This commit is contained in:
Josh Durgin 2011-12-05 10:47:13 -08:00 committed by Alex Elder
parent 50f7c4c967
commit 403f24d3d5

View file

@ -1684,7 +1684,9 @@ static int rbd_header_add_snap(struct rbd_device *dev,
if (ret < 0)
return ret;
dev->header.snapc->seq = new_snapid;
down_write(&dev->header_rwsem);
dev->header.snapc->seq = new_snapid;
up_write(&dev->header_rwsem);
return 0;
bad: