diff options
| author | Dave Chinner <dchinner@redhat.com> | 2012-11-28 03:01:02 +0100 |
|---|---|---|
| committer | Ben Myers <bpm@sgi.com> | 2012-11-29 21:24:03 +0100 |
| commit | b870553cdecb26d5291af09602352b763e323df2 (patch) | |
| tree | 4d7cfd6b3485d7e204003abc084245dc9a4e2ab5 | |
| parent | xfs: fix direct IO nested transaction deadlock. (diff) | |
| download | linux-b870553cdecb26d5291af09602352b763e323df2.tar.xz linux-b870553cdecb26d5291af09602352b763e323df2.zip | |
xfs: fix stray dquot unlock when reclaiming dquots
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.
cc: <stable@vger.kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
| -rw-r--r-- | fs/xfs/xfs_qm.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c index e6a0af0ba007..60eff4763156 100644 --- a/fs/xfs/xfs_qm.c +++ b/fs/xfs/xfs_qm.c @@ -1456,7 +1456,7 @@ 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 @@ -1479,7 +1479,7 @@ 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; @@ -1490,7 +1490,7 @@ 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); @@ -1499,7 +1499,7 @@ 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); @@ -1518,14 +1518,13 @@ 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); } |