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authorNiu Yawei <yawei.niu@gmail.com>2014-06-04 06:20:30 +0200
committerJan Kara <jack@suse.cz>2014-07-15 22:40:21 +0200
commit1ea06bec78a128adc995ca32bd906a6c9bb9cf91 (patch)
treee306601eeb564fcc425841f8591df5069e3a9d15 /fs/quota
parentquota: protect Q_GETFMT by dqonoff_mutex (diff)
downloadlinux-1ea06bec78a128adc995ca32bd906a6c9bb9cf91.tar.xz
linux-1ea06bec78a128adc995ca32bd906a6c9bb9cf91.zip
quota: avoid unnecessary dqget()/dqput() calls
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>
Diffstat (limited to 'fs/quota')
-rw-r--r--fs/quota/dquot.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 7f30bdc57d13..251771916069 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -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;