xfs: remove xfs_qm_sync

Now that we can't have any dirty dquots around that aren't in the AIL we
can get rid of the explicit dquot syncing from xfssyncd and xfs_fs_sync_fs
and instead rely on AIL pushing to write out any quota updates.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_qm.c

@@ -879,100 +879,6 @@ xfs_qm_dqdetach(
 	}
 }
 
-int
-xfs_qm_sync(
-	struct xfs_mount	*mp,
-	int			flags)
-{
-	struct xfs_quotainfo	*q = mp->m_quotainfo;
-	int			recl, restarts;
-	struct xfs_dquot	*dqp;
-	int			error;
-
-	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
-		return 0;
-
-	restarts = 0;
-
-  again:
-	mutex_lock(&q->qi_dqlist_lock);
-	/*
-	 * dqpurge_all() also takes the mplist lock and iterate thru all dquots
-	 * in quotaoff. However, if the QUOTA_ACTIVE bits are not cleared
-	 * when we have the mplist lock, we know that dquots will be consistent
-	 * as long as we have it locked.
-	 */
-	if (!XFS_IS_QUOTA_ON(mp)) {
-		mutex_unlock(&q->qi_dqlist_lock);
-		return 0;
-	}
-	ASSERT(mutex_is_locked(&q->qi_dqlist_lock));
-	list_for_each_entry(dqp, &q->qi_dqlist, q_mplist) {
-		/*
-		 * If this is vfs_sync calling, then skip the dquots that
-		 * don't 'seem' to be dirty. ie. don't acquire dqlock.
-		 * This is very similar to what xfs_sync does with inodes.
-		 */
-		if (flags & SYNC_TRYLOCK) {
-			if (!XFS_DQ_IS_DIRTY(dqp))
-				continue;
-			if (!xfs_qm_dqlock_nowait(dqp))
-				continue;
-		} else {
-			xfs_dqlock(dqp);
-		}
-
-		/*
-		 * Now, find out for sure if this dquot is dirty or not.
-		 */
-		if (! XFS_DQ_IS_DIRTY(dqp)) {
-			xfs_dqunlock(dqp);
-			continue;
-		}
-
-		/* XXX a sentinel would be better */
-		recl = q->qi_dqreclaims;
-		if (!xfs_dqflock_nowait(dqp)) {
-			if (flags & SYNC_TRYLOCK) {
-				xfs_dqunlock(dqp);
-				continue;
-			}
-			/*
-			 * If we can't grab the flush lock then if the caller
-			 * really wanted us to give this our best shot, so
-			 * see if we can give a push to the buffer before we wait
-			 * on the flush lock. At this point, we know that
-			 * even though the dquot is being flushed,
-			 * it has (new) dirty data.
-			 */
-			xfs_qm_dqflock_pushbuf_wait(dqp);
-		}
-		/*
-		 * Let go of the mplist lock. We don't want to hold it
-		 * across a disk write
-		 */
-		mutex_unlock(&q->qi_dqlist_lock);
-		error = xfs_qm_dqflush(dqp, flags);
-		xfs_dqunlock(dqp);
-		if (error && XFS_FORCED_SHUTDOWN(mp))
-			return 0;	/* Need to prevent umount failure */
-		else if (error)
-			return error;
-
-		mutex_lock(&q->qi_dqlist_lock);
-		if (recl != q->qi_dqreclaims) {
-			if (++restarts >= XFS_QM_SYNC_MAX_RESTARTS)
-				break;
-
-			mutex_unlock(&q->qi_dqlist_lock);
-			goto again;
-		}
-	}
-
-	mutex_unlock(&q->qi_dqlist_lock);
-	return 0;
-}
-
 /*
  * The hash chains and the mplist use the same xfs_dqhash structure as
  * their list head, but we can take the mplist qh_lock and one of the

fs/xfs/xfs_qm.h

@@ -32,12 +32,6 @@ extern struct xfs_qm	*xfs_Gqm;
 extern kmem_zone_t	*qm_dqzone;
 extern kmem_zone_t	*qm_dqtrxzone;
 
-/*
- * Used in xfs_qm_sync called by xfs_sync to count the max times that it can
- * iterate over the mountpt's dquot list in one call.
- */
-#define XFS_QM_SYNC_MAX_RESTARTS	7
-
 /*
  * Ditto, for xfs_qm_dqreclaim_one.
  */

fs/xfs/xfs_quota.h

@@ -326,7 +326,6 @@ extern int xfs_qm_dqattach_locked(struct xfs_inode *, uint);
 extern void xfs_qm_dqdetach(struct xfs_inode *);
 extern void xfs_qm_dqrele(struct xfs_dquot *);
 extern void xfs_qm_statvfs(struct xfs_inode *, struct kstatfs *);
-extern int xfs_qm_sync(struct xfs_mount *, int);
 extern int xfs_qm_newmount(struct xfs_mount *, uint *, uint *);
 extern void xfs_qm_mount_quotas(struct xfs_mount *);
 extern void xfs_qm_unmount(struct xfs_mount *);
@@ -366,10 +365,6 @@ static inline int xfs_trans_reserve_quota_bydquots(struct xfs_trans *tp,
 #define xfs_qm_dqdetach(ip)
 #define xfs_qm_dqrele(d)
 #define xfs_qm_statvfs(ip, s)
-static inline int xfs_qm_sync(struct xfs_mount *mp, int flags)
-{
-	return 0;
-}
 #define xfs_qm_newmount(mp, a, b)					(0)
 #define xfs_qm_mount_quotas(mp)
 #define xfs_qm_unmount(mp)

fs/xfs/xfs_super.c

@@ -1025,17 +1025,10 @@ xfs_fs_sync_fs(
 	int			error;
 
 	/*
-	 * Not much we can do for the first async pass.  Writing out the
-	 * superblock would be counter-productive as we are going to redirty
-	 * when writing out other data and metadata (and writing out a single
-	 * block is quite fast anyway).
-	 *
-	 * Try to asynchronously kick off quota syncing at least.
+	 * Doing anything during the async pass would be counterproductive.
 	 */
-	if (!wait) {
-		xfs_qm_sync(mp, SYNC_TRYLOCK);
+	if (!wait)
 		return 0;
-	}
 
 	error = xfs_quiesce_data(mp);
 	if (error)

fs/xfs/xfs_sync.c

@@ -359,10 +359,7 @@ xfs_quiesce_data(
 {
 	int			error, error2 = 0;
 
-	xfs_qm_sync(mp, SYNC_TRYLOCK);
-	xfs_qm_sync(mp, SYNC_WAIT);
-
-	/* force out the newly dirtied log buffers */
+	/* force out the log */
 	xfs_log_force(mp, XFS_LOG_SYNC);
 
 	/* write superblock and hoover up shutdown errors */
@@ -470,7 +467,6 @@ xfs_sync_worker(
 			error = xfs_fs_log_dummy(mp);
 		else
 			xfs_log_force(mp, 0);
-		error = xfs_qm_sync(mp, SYNC_TRYLOCK);
 
 		/* start pushing all the metadata that is currently dirty */
 		xfs_ail_push_all(mp->m_ail);