[PATCH 8/8] quota: Introduce writeout_quota_sb() (version 4)

[Jan Kara <jack@suse.cz>]

Introduce this function which just writes all the quota structures but
avoids all the syncing and cache pruning work to expose quota structures
to userspace. Use this function from __sync_filesystem when wait == 0.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/sync.c                |    6 +++++-
 include/linux/quotaops.h |    9 +++++++++
 2 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/fs/sync.c b/fs/sync.c
index 4914f0a..8a14e20 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -26,7 +26,11 @@
  */
 static int __sync_filesystem(struct super_block *sb, int wait)
 {
-	sync_quota_sb(sb, -1);
+	/* Avoid doing twice syncing and cache pruning for quota sync */
+	if (!wait)
+		writeout_quota_sb(sb, -1);
+	else
+		sync_quota_sb(sb, -1);
 	sync_inodes_sb(sb, wait);
 	lock_super(sb);
 	if (sb->s_dirt && sb->s_op->write_super)
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 047310f..7bc4575 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -21,6 +21,11 @@ static inline struct quota_info *sb_dqopt(struct super_block *sb)
  * declaration of quota_function calls in kernel.
  */
 void sync_quota_sb(struct super_block *sb, int type);
+static inline void writeout_quota_sb(struct super_block *sb, int type)
+{
+	if (sb->s_qcop->quota_sync)
+		sb->s_qcop->quota_sync(sb, type);
+}
 
 int dquot_initialize(struct inode *inode, int type);
 int dquot_drop(struct inode *inode);
@@ -333,6 +338,10 @@ static inline void sync_quota_sb(struct super_block *sb, int type)
 {
 }
 
+static inline void writeout_quota_sb(struct super_block *sb, int type)
+{
+}
+
 static inline int vfs_dq_off(struct super_block *sb, int remount)
 {
 	return 0;
-- 
1.6.0.2