Avoid unnecessary dqget()/dqput() calls in __dquot_initialize(),
that will introduce global lock contention otherwise.
Signed-off-by: Lai Siyao <lai.siyao@xxxxxxxxx>
Signed-off-by: Niu Yawei <yawei.niu@xxxxxxxxx>
---
fs/quota/dquot.c | 13 ++++++++++++-
1 files changed, 12 insertions(+), 1 deletions(-)
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 9cd5f63..dc6f711 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -1400,7 +1400,7 @@ static int dquot_active(const struct inode *inode)
*/
static void __dquot_initialize(struct inode *inode, int type)
{
- int cnt;
+ int cnt, dq_get = 0;
struct dquot *got[MAXQUOTAS];
struct super_block *sb = inode->i_sb;
qsize_t rsv;
@@ -1416,6 +1416,13 @@ static void __dquot_initialize(struct inode *inode, int type)
got[cnt] = NULL;
if (type != -1 && cnt != type)
continue;
+ /* the i_dquot should have been initialized in most case,
+ * we check it without locking here to avoid unnecessary
+ * dqget()/dqput() calls. */
+ if (inode->i_dquot[cnt])
+ continue;
+ dq_get = 1;
+
switch (cnt) {
case USRQUOTA:
qid = make_kqid_uid(inode->i_uid);
@@ -1427,6 +1434,10 @@ static void __dquot_initialize(struct inode *inode, int type)
got[cnt] = dqget(sb, qid);
}
+ /* all required i_dquot has been initialized */
+ if (!dq_get)
+ return;
+
down_write(&sb_dqopt(sb)->dqptr_sem);
if (IS_NOQUOTA(inode))
goto out_err;
--
1.7.1
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