Currently dquot writeout is only protected by dqio_sem held for writing.
As we transition to a finer grained locking we will use dquot->dq_lock
instead. So acquire it in dquot_commit() and move dqio_sem just around
->commit_dqblk() call as it is still needed to serialize quota file
changes.
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/quota/dquot.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 3852a3c79ac9..8b52e852eba2 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -110,14 +110,11 @@
* sure they cannot race with quotaon which first sets S_NOQUOTA flag and
* then drops all pointers to dquots from an inode.
*
- * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
- * from inodes (dquot_alloc_space() and such don't check the dq_lock).
- * Currently dquot is locked only when it is being read to memory (or space for
- * it is being allocated) on the first dqget() and when it is being released on
- * the last dqput(). The allocation and release oparations are serialized by
- * the dq_lock and by checking the use count in dquot_release(). Write
- * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
- * spinlock to internal buffers before writing.
+ * Each dquot has its dq_lock mutex. Dquot is locked when it is being read to
+ * memory (or space for it is being allocated) on the first dqget(), when it is
+ * being written out, and when it is being released on the last dqput(). The
+ * allocation and release operations are serialized by the dq_lock and by
+ * checking the use count in dquot_release().
*
* Lock ordering (including related VFS locks) is the following:
* s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_sem
@@ -453,21 +450,24 @@ int dquot_commit(struct dquot *dquot)
int ret = 0;
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
- down_write(&dqopt->dqio_sem);
+ mutex_lock(&dquot->dq_lock);
spin_lock(&dq_list_lock);
if (!clear_dquot_dirty(dquot)) {
spin_unlock(&dq_list_lock);
- goto out_sem;
+ goto out_lock;
}
spin_unlock(&dq_list_lock);
/* Inactive dquot can be only if there was error during read/init
* => we have better not writing it */
- if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
+ if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
+ down_write(&dqopt->dqio_sem);
ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
- else
+ up_write(&dqopt->dqio_sem);
+ } else {
ret = -EIO;
-out_sem:
- up_write(&dqopt->dqio_sem);
+ }
+out_lock:
+ mutex_unlock(&dquot->dq_lock);
return ret;
}
EXPORT_SYMBOL(dquot_commit);
--
2.12.3
