From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Delegate the dquot cache handling (radix tree lookup and insertion) to
separate helper functions so that we can continue to simplify the body
of dqget.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/xfs_dquot.c | 112 ++++++++++++++++++++++++++++++++++++----------------
1 file changed, 78 insertions(+), 34 deletions(-)
diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index 8d2a3becc4f4..299d4ce90ded 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -686,6 +686,81 @@ xfs_dq_get_next_id(
return error;
}
+/*
+ * Look up the dquot in the in-core cache. If found, the dquot is returned
+ * locked and ready to go.
+ */
+static struct xfs_dquot *
+xfs_qm_dqget_cache_lookup(
+ struct xfs_mount *mp,
+ struct xfs_quotainfo *qi,
+ struct radix_tree_root *tree,
+ xfs_dqid_t id)
+{
+ struct xfs_dquot *dqp;
+
+restart:
+ mutex_lock(&qi->qi_tree_lock);
+ dqp = radix_tree_lookup(tree, id);
+ if (!dqp) {
+ mutex_unlock(&qi->qi_tree_lock);
+ XFS_STATS_INC(mp, xs_qm_dqcachemisses);
+ return NULL;
+ }
+
+ xfs_dqlock(dqp);
+ if (dqp->dq_flags & XFS_DQ_FREEING) {
+ xfs_dqunlock(dqp);
+ mutex_unlock(&qi->qi_tree_lock);
+ trace_xfs_dqget_freeing(dqp);
+ delay(1);
+ goto restart;
+ }
+
+ dqp->q_nrefs++;
+ mutex_unlock(&qi->qi_tree_lock);
+
+ trace_xfs_dqget_hit(dqp);
+ XFS_STATS_INC(mp, xs_qm_dqcachehits);
+ return dqp;
+}
+
+/*
+ * Try to insert a new dquot into the in-core cache. If an error occurs the
+ * caller should throw away the dquot and start over. Otherwise, the dquot
+ * is returned locked (and held by the cache) as if there had been a cache
+ * hit.
+ */
+static int
+xfs_qm_dqget_cache_insert(
+ struct xfs_mount *mp,
+ struct xfs_quotainfo *qi,
+ struct radix_tree_root *tree,
+ xfs_dqid_t id,
+ struct xfs_dquot *dqp)
+{
+ int error;
+
+ mutex_lock(&qi->qi_tree_lock);
+ error = radix_tree_insert(tree, id, dqp);
+ if (unlikely(error)) {
+ /* Duplicate found! Caller must try again. */
+ WARN_ON(error != -EEXIST);
+ mutex_unlock(&qi->qi_tree_lock);
+ trace_xfs_dqget_dup(dqp);
+ return error;
+ }
+
+ /* Return a locked dquot to the caller, with a reference taken. */
+ xfs_dqlock(dqp);
+ dqp->q_nrefs = 1;
+
+ qi->qi_dquots++;
+ mutex_unlock(&qi->qi_tree_lock);
+
+ return 0;
+}
+
/*
* Given the file system, inode OR id, and type (UDQUOT/GDQUOT), return a
* a locked dquot, doing an allocation (if requested) as needed.
@@ -724,28 +799,11 @@ xfs_qm_dqget(
}
restart:
- mutex_lock(&qi->qi_tree_lock);
- dqp = radix_tree_lookup(tree, id);
+ dqp = xfs_qm_dqget_cache_lookup(mp, qi, tree, id);
if (dqp) {
- xfs_dqlock(dqp);
- if (dqp->dq_flags & XFS_DQ_FREEING) {
- xfs_dqunlock(dqp);
- mutex_unlock(&qi->qi_tree_lock);
- trace_xfs_dqget_freeing(dqp);
- delay(1);
- goto restart;
- }
-
- dqp->q_nrefs++;
- mutex_unlock(&qi->qi_tree_lock);
-
- trace_xfs_dqget_hit(dqp);
- XFS_STATS_INC(mp, xs_qm_dqcachehits);
*O_dqpp = dqp;
return 0;
}
- mutex_unlock(&qi->qi_tree_lock);
- XFS_STATS_INC(mp, xs_qm_dqcachemisses);
/*
* Dquot cache miss. We don't want to keep the inode lock across
@@ -787,31 +845,17 @@ xfs_qm_dqget(
}
}
- mutex_lock(&qi->qi_tree_lock);
- error = radix_tree_insert(tree, id, dqp);
- if (unlikely(error)) {
- WARN_ON(error != -EEXIST);
-
+ error = xfs_qm_dqget_cache_insert(mp, qi, tree, id, dqp);
+ if (error) {
/*
* Duplicate found. Just throw away the new dquot and start
* over.
*/
- mutex_unlock(&qi->qi_tree_lock);
- trace_xfs_dqget_dup(dqp);
xfs_qm_dqdestroy(dqp);
XFS_STATS_INC(mp, xs_qm_dquot_dups);
goto restart;
}
- /*
- * We return a locked dquot to the caller, with a reference taken
- */
- xfs_dqlock(dqp);
- dqp->q_nrefs = 1;
-
- qi->qi_dquots++;
- mutex_unlock(&qi->qi_tree_lock);
-
dqret:
ASSERT((ip == NULL) || xfs_isilocked(ip, XFS_ILOCK_EXCL));
trace_xfs_dqget_miss(dqp);
--
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