This is a note to let you know that I've just added the patch titled
xfs: fix stray dquot unlock when reclaiming dquots
to the 3.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xfs-fix-stray-dquot-unlock-when-reclaiming-dquots.patch
and it can be found in the queue-3.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From b870553cdecb26d5291af09602352b763e323df2 Mon Sep 17 00:00:00 2001
From: Dave Chinner <[email protected]>
Date: Wed, 28 Nov 2012 13:01:02 +1100
Subject: xfs: fix stray dquot unlock when reclaiming dquots
From: Dave Chinner <[email protected]>
commit b870553cdecb26d5291af09602352b763e323df2 upstream.
When we fail to get a dquot lock during reclaim, we jump to an error
handler that unlocks the dquot. This is wrong as we didn't lock the
dquot, and unlocking it means who-ever is holding the lock has had
it silently taken away, and hence it results in a lock imbalance.
Found by inspection while modifying the code for the numa-lru
patchset. This fixes a random hang I've been seeing on xfstest 232
for the past several months.
Signed-off-by: Dave Chinner <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Ben Myers <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/xfs/xfs_qm.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -1453,7 +1453,7 @@ xfs_qm_dqreclaim_one(
int error;
if (!xfs_dqlock_nowait(dqp))
- goto out_busy;
+ goto out_move_tail;
/*
* This dquot has acquired a reference in the meantime remove it from
@@ -1476,7 +1476,7 @@ xfs_qm_dqreclaim_one(
* getting flushed to disk, we don't want to reclaim it.
*/
if (!xfs_dqflock_nowait(dqp))
- goto out_busy;
+ goto out_unlock_move_tail;
if (XFS_DQ_IS_DIRTY(dqp)) {
struct xfs_buf *bp = NULL;
@@ -1487,7 +1487,7 @@ xfs_qm_dqreclaim_one(
if (error) {
xfs_warn(mp, "%s: dquot %p flush failed",
__func__, dqp);
- goto out_busy;
+ goto out_unlock_move_tail;
}
xfs_buf_delwri_queue(bp, buffer_list);
@@ -1496,7 +1496,7 @@ xfs_qm_dqreclaim_one(
* Give the dquot another try on the freelist, as the
* flushing will take some time.
*/
- goto out_busy;
+ goto out_unlock_move_tail;
}
xfs_dqfunlock(dqp);
@@ -1515,14 +1515,13 @@ xfs_qm_dqreclaim_one(
XFS_STATS_INC(xs_qm_dqreclaims);
return;
-out_busy:
- xfs_dqunlock(dqp);
-
/*
* Move the dquot to the tail of the list so that we don't spin on it.
*/
+out_unlock_move_tail:
+ xfs_dqunlock(dqp);
+out_move_tail:
list_move_tail(&dqp->q_lru, &qi->qi_lru_list);
-
trace_xfs_dqreclaim_busy(dqp);
XFS_STATS_INC(xs_qm_dqreclaim_misses);
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.7/xfs-fix-direct-io-nested-transaction-deadlock.patch
queue-3.7/xfs-fix-stray-dquot-unlock-when-reclaiming-dquots.patch
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