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| author | Christoph Hellwig <hch@lst.de> | 2009-01-19 02:03:19 +0100 |
|---|---|---|
| committer | Lachlan McIlroy <lachlan@sgi.com> | 2009-01-19 14:44:52 +1100 |
| commit | 4f2d4ac6e5eb7d72e8df7f3fbf67a78dab8b91cf (patch) | |
| tree | 821d74c2055ebbc8070db1e881762bcc805e90a5 /fs | |
| parent | 080dda7f5e8e8df95bcd17a5345c276e365a2054 (diff) | |
| download | linux-4f2d4ac6e5eb7d72e8df7f3fbf67a78dab8b91cf.tar.gz linux-4f2d4ac6e5eb7d72e8df7f3fbf67a78dab8b91cf.tar.bz2 linux-4f2d4ac6e5eb7d72e8df7f3fbf67a78dab8b91cf.zip | |
xfs: lockdep annotations for xfs_dqlock2
xfs_dqlock2 locks two xfs_dquots, which is fine as it always locks the
dquot with the lower id first. Use mutex_lock_nested to tell lockdep
about this fact.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/xfs/quota/xfs_dquot.c | 24 | ||||
| -rw-r--r-- | fs/xfs/quota/xfs_dquot.h | 10 |
2 files changed, 24 insertions, 10 deletions
diff --git a/fs/xfs/quota/xfs_dquot.c b/fs/xfs/quota/xfs_dquot.c index 591ca6602bfb..36d1bb6140d1 100644 --- a/fs/xfs/quota/xfs_dquot.c +++ b/fs/xfs/quota/xfs_dquot.c @@ -1383,6 +1383,12 @@ xfs_dqunlock_nonotify( mutex_unlock(&(dqp->q_qlock)); } +/* + * Lock two xfs_dquot structures. + * + * To avoid deadlocks we always lock the quota structure with + * the lowerd id first. + */ void xfs_dqlock2( xfs_dquot_t *d1, @@ -1392,18 +1398,16 @@ xfs_dqlock2( ASSERT(d1 != d2); if (be32_to_cpu(d1->q_core.d_id) > be32_to_cpu(d2->q_core.d_id)) { - xfs_dqlock(d2); - xfs_dqlock(d1); + mutex_lock(&d2->q_qlock); + mutex_lock_nested(&d1->q_qlock, XFS_QLOCK_NESTED); } else { - xfs_dqlock(d1); - xfs_dqlock(d2); - } - } else { - if (d1) { - xfs_dqlock(d1); - } else if (d2) { - xfs_dqlock(d2); + mutex_lock(&d1->q_qlock); + mutex_lock_nested(&d2->q_qlock, XFS_QLOCK_NESTED); } + } else if (d1) { + mutex_lock(&d1->q_qlock); + } else if (d2) { + mutex_lock(&d2->q_qlock); } } diff --git a/fs/xfs/quota/xfs_dquot.h b/fs/xfs/quota/xfs_dquot.h index 7e455337e2ba..d443e93b4331 100644 --- a/fs/xfs/quota/xfs_dquot.h +++ b/fs/xfs/quota/xfs_dquot.h @@ -97,6 +97,16 @@ typedef struct xfs_dquot { #define dq_hashlist q_lists.dqm_hashlist #define dq_flags q_lists.dqm_flags +/* + * Lock hierachy for q_qlock: + * XFS_QLOCK_NORMAL is the implicit default, + * XFS_QLOCK_NESTED is the dquot with the higher id in xfs_dqlock2 + */ +enum { + XFS_QLOCK_NORMAL = 0, + XFS_QLOCK_NESTED, +}; + #define XFS_DQHOLD(dqp) ((dqp)->q_nrefs++) #ifdef DEBUG |