quota: Introduce DQUOT_QUOTA_SYS_FILE flag

If filesystem can handle quota files as system files hidden from users, we can
skip a lot of cache invalidation, syncing, inode flags setting etc. when
turning quotas on, off and quota_sync. Allow filesystem to indicate that it is
hiding quota files from users by DQUOT_QUOTA_SYS_FILE flag.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/quota.c b/fs/quota.c
index 8678d9f35ee9..4a8c94f05f76 100644
--- a/fs/quota.c
+++ b/fs/quota.c
@@ -160,6 +160,9 @@ static void quota_sync_sb(struct super_block *sb, int type)
         int cnt;
 
         sb->s_qcop->quota_sync(sb, type);
+
+        if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
+                return;
         /* This is not very clever (and fast) but currently I don't know about
          * any other simple way of getting quota data to disk and we must get
          * them there for userspace to be visible... */