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quota: avoid unnecessary dqget()/dqput() calls

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Avoid unnecessary dqget()/dqput() calls in __dquot_initialize(),
that will introduce global lock contention otherwise.

Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Niu Yawei 2014-06-04 12:20:30 +08:00 committed by Jan Kara
parent 606cdcca04
commit 1ea06bec78
1 changed files with 14 additions and 1 deletions
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15
fs/quota/dquot.c
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@ -1402,7 +1402,7 @@ static int dquot_active(const struct inode *inode)
*/
static void __dquot_initialize(struct inode *inode, int type)
{
int cnt;
int cnt, init_needed = 0;
struct dquot *got[MAXQUOTAS];
struct super_block *sb = inode->i_sb;
qsize_t rsv;
@ -1418,6 +1418,15 @@ 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 cases,
* we check it without locking here to avoid unnecessary
* dqget()/dqput() calls.
*/
if (inode->i_dquot[cnt])
continue;
init_needed = 1;
switch (cnt) {
case USRQUOTA:
qid = make_kqid_uid(inode->i_uid);
@ -1429,6 +1438,10 @@ static void __dquot_initialize(struct inode *inode, int type)
got[cnt] = dqget(sb, qid);
}
/* All required i_dquot has been initialized */
if (!init_needed)
return;
down_write(&sb_dqopt(sb)->dqptr_sem);
if (IS_NOQUOTA(inode))
goto out_err;