quota: move code from sync_quota_sb into vfs_quota_sync

Currenly sync_quota_sb does a lot of sync and truncate action that only
applies to "VFS" style quotas and is actively harmful for the sync
performance in XFS.  Move it into vfs_quota_sync and add a wait parameter
to ->quota_sync to tell if we need it or not.

My audit of the GFS2 code says it's also not needed given the way GFS2
implements quotas, but I'd be happy if this can get a detailed review.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index e3bf6ea..6dbcbad 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -1083,7 +1083,7 @@
 	}
 }
 
-int gfs2_quota_sync(struct super_block *sb, int type)
+int gfs2_quota_sync(struct super_block *sb, int type, int wait)
 {
 	struct gfs2_sbd *sdp = sb->s_fs_info;
 	struct gfs2_quota_data **qda;
@@ -1127,6 +1127,11 @@
 	return error;
 }
 
+static int gfs2_quota_sync_timeo(struct super_block *sb, int type)
+{
+	return gfs2_quota_sync(sb, type, 0);
+}
+
 int gfs2_quota_refresh(struct gfs2_sbd *sdp, int user, u32 id)
 {
 	struct gfs2_quota_data *qd;
@@ -1382,7 +1387,7 @@
 					   &tune->gt_statfs_quantum);
 
 		/* Update quota file */
-		quotad_check_timeo(sdp, "sync", gfs2_quota_sync, t,
+		quotad_check_timeo(sdp, "sync", gfs2_quota_sync_timeo, t,
 				   &quotad_timeo, &tune->gt_quota_quantum);
 
 		/* Check for & recover partially truncated inodes */