| From | Greg Kroah-Hartman <> | Subject | [ 089/171] rbd: protect read of snapshot sequence number | Date | Wed, 21 Nov 2012 16:40:35 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Josh Durgin <josh.durgin@dreamhost.com>
(cherry picked from commit 403f24d3d51760a8b9368d595fa5f48c309f1a0f)
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/block/rbd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -1683,7 +1683,9 @@ static int rbd_header_add_snap(struct rb 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:
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