[ 063/136 ] LOCKD: Ensure that nlmclnt_block resets block->b_status after a server reboot

Steven Rostedt
2013-05-18T03:01:24Z

[-- Attachment #1: 0063-LOCKD-Ensure-that-nlmclnt_block-resets-block-b_statu.patch --]
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3.6.11.4 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Trond Myklebust <Trond.Myklebust@netapp.com>

[ Upstream commit 1dfd89af8697a299e7982ae740d4695ecd917eef ]

After a server reboot, the reclaimer thread will recover all the existing
locks. For locks that are blocked, however, it will change the value
of block->b_status to nlm_lck_denied_grace_period in order to signal that
they need to wake up and resend the original blocking lock request.

Due to a bug, however, the block->b_status never gets reset after the
blocked locks have been woken up, and so the process goes into an
infinite loop of resends until the blocked lock is satisfied.

Reported-by: Marc Eshel <eshel@us.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
fs/lockd/clntlock.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index ca0a080..193f04c 100644
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -144,6 +144,9 @@ int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
timeout);
if (ret < 0)
return -ERESTARTSYS;
+ /* Reset the lock status after a server reboot so we resend */
+ if (block->b_status == nlm_lck_denied_grace_period)
+ block->b_status = nlm_lck_blocked;
req->a_res.status = block->b_status;
return 0;
}
--
1.7.10.4