[ 3.5.y.z extended stable ] Patch "xfs: fix stray dquot unlock when reclaiming dquots" has been added to staging queue
Herton Ronaldo Krzesinski
herton.krzesinski at canonical.com
Mon Jan 7 20:35:35 UTC 2013
This is a note to let you know that I have just added a patch titled
xfs: fix stray dquot unlock when reclaiming dquots
to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Herton
------
>From 5ff4894eb72f5aa70ab0ed4de1c45296335da955 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner at redhat.com>
Date: Wed, 28 Nov 2012 13:01:02 +1100
Subject: [PATCH] xfs: fix stray dquot unlock when reclaiming dquots
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 <dchinner at redhat.com>
Reviewed-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Ben Myers <bpm at sgi.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
fs/xfs/xfs_qm.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 249db19..92eb490 100644
--- 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);
}
--
1.7.9.5
More information about the kernel-team
mailing list