19 files changed, 442 insertions, 918 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 6819b5163e3..b82fc5c67fe 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -42,7 +42,6 @@
 #include "xfs_trace.h"
 
 static kmem_zone_t *xfs_buf_zone;
-STATIC int xfsbufd(void *);
 
 static struct workqueue_struct *xfslogd_workqueue;
 
@@ -144,8 +143,17 @@ void
 xfs_buf_stale(
 	struct xfs_buf	*bp)
 {
+	ASSERT(xfs_buf_islocked(bp));
+
 	bp->b_flags |= XBF_STALE;
-	xfs_buf_delwri_dequeue(bp);
+
+	/*
+	 * Clear the delwri status so that a delwri queue walker will not
+	 * flush this buffer to disk now that it is stale. The delwri queue has
+	 * a reference to the buffer, so this is safe to do.
+	 */
+	bp->b_flags &= ~_XBF_DELWRI_Q;
+
 	atomic_set(&(bp)->b_lru_ref, 0);
 	if (!list_empty(&bp->b_lru)) {
 		struct xfs_buftarg *btp = bp->b_target;
@@ -592,10 +600,10 @@ _xfs_buf_read(
 {
 	int			status;
 
-	ASSERT(!(flags & (XBF_DELWRI|XBF_WRITE)));
+	ASSERT(!(flags & XBF_WRITE));
 	ASSERT(bp->b_bn != XFS_BUF_DADDR_NULL);
 
-	bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_DELWRI | XBF_READ_AHEAD);
+	bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD);
 	bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
 
 	status = xfs_buf_iorequest(bp);
@@ -855,7 +863,7 @@ xfs_buf_rele(
 			spin_unlock(&pag->pag_buf_lock);
 		} else {
 			xfs_buf_lru_del(bp);
-			ASSERT(!(bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)));
+			ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
 			rb_erase(&bp->b_rbnode, &pag->pag_buf_tree);
 			spin_unlock(&pag->pag_buf_lock);
 			xfs_perag_put(pag);
@@ -915,13 +923,6 @@ xfs_buf_lock(
 	trace_xfs_buf_lock_done(bp, _RET_IP_);
 }
 
-/*
- *	Releases the lock on the buffer object.
- *	If the buffer is marked delwri but is not queued, do so before we
- *	unlock the buffer as we need to set flags correctly.  We also need to
- *	take a reference for the delwri queue because the unlocker is going to
- *	drop their's and they don't know we just queued it.
- */
 void
 xfs_buf_unlock(
 	struct xfs_buf		*bp)
@@ -1019,10 +1020,11 @@ xfs_bwrite(
 {
 	int			error;
 
+	ASSERT(xfs_buf_islocked(bp));
+
 	bp->b_flags |= XBF_WRITE;
-	bp->b_flags &= ~(XBF_ASYNC | XBF_READ);
+	bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q);
 
-	xfs_buf_delwri_dequeue(bp);
 	xfs_bdstrat_cb(bp);
 
 	error = xfs_buf_iowait(bp);
@@ -1254,7 +1256,7 @@ xfs_buf_iorequest(
 {
 	trace_xfs_buf_iorequest(bp, _RET_IP_);
 
-	ASSERT(!(bp->b_flags & XBF_DELWRI));
+	ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
 
 	if (bp->b_flags & XBF_WRITE)
 		xfs_buf_wait_unpin(bp);
@@ -1435,11 +1437,9 @@ xfs_free_buftarg(
 {
 	unregister_shrinker(&btp->bt_shrinker);
 
-	xfs_flush_buftarg(btp, 1);
 	if (mp->m_flags & XFS_MOUNT_BARRIER)
 		xfs_blkdev_issue_flush(btp);
 
-	kthread_stop(btp->bt_task);
 	kmem_free(btp);
 }
 
@@ -1491,20 +1491,6 @@ xfs_setsize_buftarg(
 	return xfs_setsize_buftarg_flags(btp, blocksize, sectorsize, 1);
 }
 
-STATIC int
-xfs_alloc_delwri_queue(
-	xfs_buftarg_t		*btp,
-	const char		*fsname)
-{
-	INIT_LIST_HEAD(&btp->bt_delwri_queue);
-	spin_lock_init(&btp->bt_delwri_lock);
-	btp->bt_flags = 0;
-	btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd/%s", fsname);
-	if (IS_ERR(btp->bt_task))
-		return PTR_ERR(btp->bt_task);
-	return 0;
-}
-
 xfs_buftarg_t *
 xfs_alloc_buftarg(
 	struct xfs_mount	*mp,
@@ -1527,8 +1513,6 @@ xfs_alloc_buftarg(
 	spin_lock_init(&btp->bt_lru_lock);
 	if (xfs_setsize_buftarg_early(btp, bdev))
 		goto error;
-	if (xfs_alloc_delwri_queue(btp, fsname))
-		goto error;
 	btp->bt_shrinker.shrink = xfs_buftarg_shrink;
 	btp->bt_shrinker.seeks = DEFAULT_SEEKS;
 	register_shrinker(&btp->bt_shrinker);
@@ -1539,125 +1523,52 @@ error:
 	return NULL;
 }
 
-
 /*
- *	Delayed write buffer handling
+ * Add a buffer to the delayed write list.
+ *
+ * This queues a buffer for writeout if it hasn't already been.  Note that
+ * neither this routine nor the buffer list submission functions perform
+ * any internal synchronization.  It is expected that the lists are thread-local
+ * to the callers.
+ *
+ * Returns true if we queued up the buffer, or false if it already had
+ * been on the buffer list.
  */
-void
+bool
 xfs_buf_delwri_queue(
-	xfs_buf_t		*bp)
+	struct xfs_buf		*bp,
+	struct list_head	*list)
 {
-	struct xfs_buftarg	*btp = bp->b_target;
-
-	trace_xfs_buf_delwri_queue(bp, _RET_IP_);
-
+	ASSERT(xfs_buf_islocked(bp));
 	ASSERT(!(bp->b_flags & XBF_READ));
 
-	spin_lock(&btp->bt_delwri_lock);
-	if (!list_empty(&bp->b_list)) {
-		/* if already in the queue, move it to the tail */
-		ASSERT(bp->b_flags & _XBF_DELWRI_Q);
-		list_move_tail(&bp->b_list, &btp->bt_delwri_queue);
-	} else {
-		/* start xfsbufd as it is about to have something to do */
-		if (list_empty(&btp->bt_delwri_queue))
-			wake_up_process(bp->b_target->bt_task);
-
-		atomic_inc(&bp->b_hold);
-		bp->b_flags |= XBF_DELWRI | _XBF_DELWRI_Q | XBF_ASYNC;
-		list_add_tail(&bp->b_list, &btp->bt_delwri_queue);
-	}
-	bp->b_queuetime = jiffies;
-	spin_unlock(&btp->bt_delwri_lock);
-}
-
-void
-xfs_buf_delwri_dequeue(
-	xfs_buf_t		*bp)
-{
-	int			dequeued = 0;
-
-	spin_lock(&bp->b_target->bt_delwri_lock);
-	if ((bp->b_flags & XBF_DELWRI) && !list_empty(&bp->b_list)) {
-		ASSERT(bp->b_flags & _XBF_DELWRI_Q);
-		list_del_init(&bp->b_list);
-		dequeued = 1;
+	/*
+	 * If the buffer is already marked delwri it already is queued up
+	 * by someone else for imediate writeout.  Just ignore it in that
+	 * case.
+	 */
+	if (bp->b_flags & _XBF_DELWRI_Q) {
+		trace_xfs_buf_delwri_queued(bp, _RET_IP_);
+		return false;
 	}
-	bp->b_flags &= ~(XBF_DELWRI|_XBF_DELWRI_Q);
-	spin_unlock(&bp->b_target->bt_delwri_lock);
-
-	if (dequeued)
-		xfs_buf_rele(bp);
-
-	trace_xfs_buf_delwri_dequeue(bp, _RET_IP_);
-}
 
-/*
- * If a delwri buffer needs to be pushed before it has aged out, then promote
- * it to the head of the delwri queue so that it will be flushed on the next
- * xfsbufd run. We do this by resetting the queuetime of the buffer to be older
- * than the age currently needed to flush the buffer. Hence the next time the
- * xfsbufd sees it is guaranteed to be considered old enough to flush.
- */
-void
-xfs_buf_delwri_promote(
-	struct xfs_buf	*bp)
-{
-	struct xfs_buftarg *btp = bp->b_target;
-	long		age = xfs_buf_age_centisecs * msecs_to_jiffies(10) + 1;
-
-	ASSERT(bp->b_flags & XBF_DELWRI);
-	ASSERT(bp->b_flags & _XBF_DELWRI_Q);
+	trace_xfs_buf_delwri_queue(bp, _RET_IP_);
 
 	/*
-	 * Check the buffer age before locking the delayed write queue as we
-	 * don't need to promote buffers that are already past the flush age.
+	 * If a buffer gets written out synchronously or marked stale while it
+	 * is on a delwri list we lazily remove it. To do this, the other party
+	 * clears the  _XBF_DELWRI_Q flag but otherwise leaves the buffer alone.
+	 * It remains referenced and on the list.  In a rare corner case it
+	 * might get readded to a delwri list after the synchronous writeout, in
+	 * which case we need just need to re-add the flag here.
 	 */
-	if (bp->b_queuetime < jiffies - age)
-		return;
-	bp->b_queuetime = jiffies - age;
-	spin_lock(&btp->bt_delwri_lock);
-	list_move(&bp->b_list, &btp->bt_delwri_queue);
-	spin_unlock(&btp->bt_delwri_lock);
-}
-
-/*
- * Move as many buffers as specified to the supplied list
- * idicating if we skipped any buffers to prevent deadlocks.
- */
-STATIC int
-xfs_buf_delwri_split(
-	xfs_buftarg_t	*target,
-	struct list_head *list,
-	unsigned long	age)
-{
-	xfs_buf_t	*bp, *n;
-	int		skipped = 0;
-	int		force;
-
-	force = test_and_clear_bit(XBT_FORCE_FLUSH, &target->bt_flags);
-	INIT_LIST_HEAD(list);
-	spin_lock(&target->bt_delwri_lock);
-	list_for_each_entry_safe(bp, n, &target->bt_delwri_queue, b_list) {
-		ASSERT(bp->b_flags & XBF_DELWRI);
-
-		if (!xfs_buf_ispinned(bp) && xfs_buf_trylock(bp)) {
-			if (!force &&
-			    time_before(jiffies, bp->b_queuetime + age)) {
-				xfs_buf_unlock(bp);
-				break;
-			}
-
-			bp->b_flags &= ~(XBF_DELWRI | _XBF_DELWRI_Q);
-			bp->b_flags |= XBF_WRITE;
-			list_move_tail(&bp->b_list, list);
-			trace_xfs_buf_delwri_split(bp, _RET_IP_);
-		} else
-			skipped++;
+	bp->b_flags |= _XBF_DELWRI_Q;
+	if (list_empty(&bp->b_list)) {
+		atomic_inc(&bp->b_hold);
+		list_add_tail(&bp->b_list, list);
 	}
 
-	spin_unlock(&target->bt_delwri_lock);
-	return skipped;
+	return true;
 }
 
 /*
@@ -1683,99 +1594,109 @@ xfs_buf_cmp(
 	return 0;
 }
 
-STATIC int
-xfsbufd(
-	void		*data)
+static int
+__xfs_buf_delwri_submit(
+	struct list_head	*buffer_list,
+	struct list_head	*io_list,
+	bool			wait)
 {
-	xfs_buftarg_t   *target = (xfs_buftarg_t *)data;
-
-	current->flags |= PF_MEMALLOC;
-
-	set_freezable();
+	struct blk_plug		plug;
+	struct xfs_buf		*bp, *n;
+	int			pinned = 0;
+
+	list_for_each_entry_safe(bp, n, buffer_list, b_list) {
+		if (!wait) {
+			if (xfs_buf_ispinned(bp)) {
+				pinned++;
+				continue;
+			}
+			if (!xfs_buf_trylock(bp))
+				continue;
+		} else {
+			xfs_buf_lock(bp);
+		}
 
-	do {
-		long	age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
-		long	tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10);
-		struct list_head tmp;
-		struct blk_plug plug;
+		/*
+		 * Someone else might have written the buffer synchronously or
+		 * marked it stale in the meantime.  In that case only the
+		 * _XBF_DELWRI_Q flag got cleared, and we have to drop the
+		 * reference and remove it from the list here.
+		 */
+		if (!(bp->b_flags & _XBF_DELWRI_Q)) {
+			list_del_init(&bp->b_list);
+			xfs_buf_relse(bp);
+			continue;
+		}
 
-		if (unlikely(freezing(current)))
-			try_to_freeze();
+		list_move_tail(&bp->b_list, io_list);
+		trace_xfs_buf_delwri_split(bp, _RET_IP_);
+	}
 
-		/* sleep for a long time if there is nothing to do. */
-		if (list_empty(&target->bt_delwri_queue))
-			tout = MAX_SCHEDULE_TIMEOUT;
-		schedule_timeout_interruptible(tout);
+	list_sort(NULL, io_list, xfs_buf_cmp);
 
-		xfs_buf_delwri_split(target, &tmp, age);
-		list_sort(NULL, &tmp, xfs_buf_cmp);
+	blk_start_plug(&plug);
+	list_for_each_entry_safe(bp, n, io_list, b_list) {
+		bp->b_flags &= ~(_XBF_DELWRI_Q | XBF_ASYNC);
+		bp->b_flags |= XBF_WRITE;
 
-		blk_start_plug(&plug);
-		while (!list_empty(&tmp)) {
-			struct xfs_buf *bp;
-			bp = list_first_entry(&tmp, struct xfs_buf, b_list);
+		if (!wait) {
+			bp->b_flags |= XBF_ASYNC;
 			list_del_init(&bp->b_list);
-			xfs_bdstrat_cb(bp);
 		}
-		blk_finish_plug(&plug);
-	} while (!kthread_should_stop());
+		xfs_bdstrat_cb(bp);
+	}
+	blk_finish_plug(&plug);
 
-	return 0;
+	return pinned;
 }
 
 /*
- *	Go through all incore buffers, and release buffers if they belong to
- *	the given device. This is used in filesystem error handling to
- *	preserve the consistency of its metadata.
+ * Write out a buffer list asynchronously.
+ *
+ * This will take the @buffer_list, write all non-locked and non-pinned buffers
+ * out and not wait for I/O completion on any of the buffers.  This interface
+ * is only safely useable for callers that can track I/O completion by higher
+ * level means, e.g. AIL pushing as the @buffer_list is consumed in this
+ * function.
  */
 int
-xfs_flush_buftarg(
-	xfs_buftarg_t	*target,
-	int		wait)
+xfs_buf_delwri_submit_nowait(
+	struct list_head	*buffer_list)
 {
-	xfs_buf_t	*bp;
-	int		pincount = 0;
-	LIST_HEAD(tmp_list);
-	LIST_HEAD(wait_list);
-	struct blk_plug plug;
+	LIST_HEAD		(io_list);
+	return __xfs_buf_delwri_submit(buffer_list, &io_list, false);
+}
 
-	flush_workqueue(xfslogd_workqueue);
+/*
+ * Write out a buffer list synchronously.
+ *
+ * This will take the @buffer_list, write all buffers out and wait for I/O
+ * completion on all of the buffers. @buffer_list is consumed by the function,
+ * so callers must have some other way of tracking buffers if they require such
+ * functionality.
+ */
+int
+xfs_buf_delwri_submit(
+	struct list_head	*buffer_list)
+{
+	LIST_HEAD		(io_list);
+	int			error = 0, error2;
+	struct xfs_buf		*bp;
 
-	set_bit(XBT_FORCE_FLUSH, &target->bt_flags);
-	pincount = xfs_buf_delwri_split(target, &tmp_list, 0);
+	__xfs_buf_delwri_submit(buffer_list, &io_list, true);
 
-	/*
-	 * Dropped the delayed write list lock, now walk the temporary list.
-	 * All I/O is issued async and then if we need to wait for completion
-	 * we do that after issuing all the IO.
-	 */
-	list_sort(NULL, &tmp_list, xfs_buf_cmp);
+	/* Wait for IO to complete. */
+	while (!list_empty(&io_list)) {
+		bp = list_first_entry(&io_list, struct xfs_buf, b_list);
 
-	blk_start_plug(&plug);
-	while (!list_empty(&tmp_list)) {
-		bp = list_first_entry(&tmp_list, struct xfs_buf, b_list);
-		ASSERT(target == bp->b_target);
 		list_del_init(&bp->b_list);
-		if (wait) {
-			bp->b_flags &= ~XBF_ASYNC;
-			list_add(&bp->b_list, &wait_list);
-		}
-		xfs_bdstrat_cb(bp);
-	}
-	blk_finish_plug(&plug);
-
-	if (wait) {
-		/* Wait for IO to complete. */
-		while (!list_empty(&wait_list)) {
-			bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
-
-			list_del_init(&bp->b_list);
-			xfs_buf_iowait(bp);
-			xfs_buf_relse(bp);
-		}
+		error2 = xfs_buf_iowait(bp);
+		xfs_buf_relse(bp);
+		if (!error)
+			error = error2;
 	}
 
-	return pincount;
+	return error;
 }
 
 int __init
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 5bf3be45f54..7083cf44d95 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -49,8 +49,7 @@ typedef enum {
 #define XBF_MAPPED	(1 << 3) /* buffer mapped (b_addr valid) */
 #define XBF_ASYNC	(1 << 4) /* initiator will not wait for completion */
 #define XBF_DONE	(1 << 5) /* all pages in the buffer uptodate */
-#define XBF_DELWRI	(1 << 6) /* buffer has dirty pages */
-#define XBF_STALE	(1 << 7) /* buffer has been staled, do not find it */
+#define XBF_STALE	(1 << 6) /* buffer has been staled, do not find it */
 
 /* I/O hints for the BIO layer */
 #define XBF_SYNCIO	(1 << 10)/* treat this buffer as synchronous I/O */
@@ -65,7 +64,7 @@ typedef enum {
 /* flags used only internally */
 #define _XBF_PAGES	(1 << 20)/* backed by refcounted pages */
 #define _XBF_KMEM	(1 << 21)/* backed by heap memory */
-#define _XBF_DELWRI_Q	(1 << 22)/* buffer on delwri queue */
+#define _XBF_DELWRI_Q	(1 << 22)/* buffer on a delwri queue */
 
 typedef unsigned int xfs_buf_flags_t;
 
@@ -76,7 +75,6 @@ typedef unsigned int xfs_buf_flags_t;
 	{ XBF_MAPPED,		"MAPPED" }, \
 	{ XBF_ASYNC,		"ASYNC" }, \
 	{ XBF_DONE,		"DONE" }, \
-	{ XBF_DELWRI,		"DELWRI" }, \
 	{ XBF_STALE,		"STALE" }, \
 	{ XBF_SYNCIO,		"SYNCIO" }, \
 	{ XBF_FUA,		"FUA" }, \
@@ -88,10 +86,6 @@ typedef unsigned int xfs_buf_flags_t;
 	{ _XBF_KMEM,		"KMEM" }, \
 	{ _XBF_DELWRI_Q,	"DELWRI_Q" }
 
-typedef enum {
-	XBT_FORCE_FLUSH = 0,
-} xfs_buftarg_flags_t;
-
 typedef struct xfs_buftarg {
 	dev_t			bt_dev;
 	struct block_device	*bt_bdev;
@@ -101,12 +95,6 @@ typedef struct xfs_buftarg {
 	unsigned int		bt_sshift;
 	size_t			bt_smask;
 
-	/* per device delwri queue */
-	struct task_struct	*bt_task;
-	struct list_head	bt_delwri_queue;
-	spinlock_t		bt_delwri_lock;
-	unsigned long		bt_flags;
-
 	/* LRU control structures */
 	struct shrinker		bt_shrinker;
 	struct list_head	bt_lru;
@@ -150,7 +138,6 @@ typedef struct xfs_buf {
 	struct xfs_trans	*b_transp;
 	struct page		**b_pages;	/* array of page pointers */
 	struct page		*b_page_array[XB_PAGES]; /* inline pages */
-	unsigned long		b_queuetime;	/* time buffer was queued */
 	atomic_t		b_pin_count;	/* pin count */
 	atomic_t		b_io_remaining;	/* #outstanding I/O requests */
 	unsigned int		b_page_count;	/* size of page array */
@@ -220,24 +207,22 @@ static inline int xfs_buf_geterror(xfs_buf_t *bp)
 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
 
 /* Delayed Write Buffer Routines */
-extern void xfs_buf_delwri_queue(struct xfs_buf *);
-extern void xfs_buf_delwri_dequeue(struct xfs_buf *);
-extern void xfs_buf_delwri_promote(struct xfs_buf *);
+extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
+extern int xfs_buf_delwri_submit(struct list_head *);
+extern int xfs_buf_delwri_submit_nowait(struct list_head *);
 
 /* Buffer Daemon Setup Routines */
 extern int xfs_buf_init(void);
 extern void xfs_buf_terminate(void);
 
 #define XFS_BUF_ZEROFLAGS(bp) \
-	((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI| \
+	((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
 			    XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
 
 void xfs_buf_stale(struct xfs_buf *bp);
 #define XFS_BUF_UNSTALE(bp)	((bp)->b_flags &= ~XBF_STALE)
 #define XFS_BUF_ISSTALE(bp)	((bp)->b_flags & XBF_STALE)
 
-#define XFS_BUF_ISDELAYWRITE(bp)	((bp)->b_flags & XBF_DELWRI)
-
 #define XFS_BUF_DONE(bp)	((bp)->b_flags |= XBF_DONE)
 #define XFS_BUF_UNDONE(bp)	((bp)->b_flags &= ~XBF_DONE)
 #define XFS_BUF_ISDONE(bp)	((bp)->b_flags & XBF_DONE)
@@ -287,7 +272,6 @@ extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
 extern void xfs_wait_buftarg(xfs_buftarg_t *);
 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
-extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
 
 #define xfs_getsize_buftarg(buftarg)	block_size((buftarg)->bt_bdev)
 #define xfs_readonly_buftarg(buftarg)	bdev_read_only((buftarg)->bt_bdev)
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 3a0bc38f185..fb20f384b56 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -418,7 +418,6 @@ xfs_buf_item_unpin(
 	if (freed && stale) {
 		ASSERT(bip->bli_flags & XFS_BLI_STALE);
 		ASSERT(xfs_buf_islocked(bp));
-		ASSERT(!(XFS_BUF_ISDELAYWRITE(bp)));
 		ASSERT(XFS_BUF_ISSTALE(bp));
 		ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL);
 
@@ -469,34 +468,28 @@ xfs_buf_item_unpin(
 	}
 }
 
-/*
- * This is called to attempt to lock the buffer associated with this
- * buf log item.  Don't sleep on the buffer lock.  If we can't get
- * the lock right away, return 0.  If we can get the lock, take a
- * reference to the buffer. If this is a delayed write buffer that
- * needs AIL help to be written back, invoke the pushbuf routine
- * rather than the normal success path.
- */
 STATIC uint
-xfs_buf_item_trylock(
-	struct xfs_log_item	*lip)
+xfs_buf_item_push(
+	struct xfs_log_item	*lip,
+	struct list_head	*buffer_list)
 {
 	struct xfs_buf_log_item	*bip = BUF_ITEM(lip);
 	struct xfs_buf		*bp = bip->bli_buf;
+	uint			rval = XFS_ITEM_SUCCESS;
 
 	if (xfs_buf_ispinned(bp))
 		return XFS_ITEM_PINNED;
 	if (!xfs_buf_trylock(bp))
 		return XFS_ITEM_LOCKED;
 
-	/* take a reference to the buffer.  */
-	xfs_buf_hold(bp);
-
 	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
-	trace_xfs_buf_item_trylock(bip);
-	if (XFS_BUF_ISDELAYWRITE(bp))
-		return XFS_ITEM_PUSHBUF;
-	return XFS_ITEM_SUCCESS;
+
+	trace_xfs_buf_item_push(bip);
+
+	if (!xfs_buf_delwri_queue(bp, buffer_list))
+		rval = XFS_ITEM_FLUSHING;
+	xfs_buf_unlock(bp);
+	return rval;
 }
 
 /*
@@ -609,48 +602,6 @@ xfs_buf_item_committed(
 	return lsn;
 }
 
-/*
- * The buffer is locked, but is not a delayed write buffer.
- */
-STATIC void
-xfs_buf_item_push(
-	struct xfs_log_item	*lip)
-{
-	struct xfs_buf_log_item	*bip = BUF_ITEM(lip);
-	struct xfs_buf		*bp = bip->bli_buf;
-
-	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
-	ASSERT(!XFS_BUF_ISDELAYWRITE(bp));
-
-	trace_xfs_buf_item_push(bip);
-
-	xfs_buf_delwri_queue(bp);
-	xfs_buf_relse(bp);
-}
-
-/*
- * The buffer is locked and is a delayed write buffer. Promote the buffer
- * in the delayed write queue as the caller knows that they must invoke
- * the xfsbufd to get this buffer written. We have to unlock the buffer
- * to allow the xfsbufd to write it, too.
- */
-STATIC bool
-xfs_buf_item_pushbuf(
-	struct xfs_log_item	*lip)
-{
-	struct xfs_buf_log_item	*bip = BUF_ITEM(lip);
-	struct xfs_buf		*bp = bip->bli_buf;
-
-	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
-	ASSERT(XFS_BUF_ISDELAYWRITE(bp));
-
-	trace_xfs_buf_item_pushbuf(bip);
-
-	xfs_buf_delwri_promote(bp);
-	xfs_buf_relse(bp);
-	return true;
-}
-
 STATIC void
 xfs_buf_item_committing(
 	struct xfs_log_item	*lip,
@@ -666,11 +617,9 @@ static const struct xfs_item_ops xfs_buf_item_ops = {
 	.iop_format	= xfs_buf_item_format,
 	.iop_pin	= xfs_buf_item_pin,
 	.iop_unpin	= xfs_buf_item_unpin,
-	.iop_trylock	= xfs_buf_item_trylock,
 	.iop_unlock	= xfs_buf_item_unlock,
 	.iop_committed	= xfs_buf_item_committed,
 	.iop_push	= xfs_buf_item_push,
-	.iop_pushbuf	= xfs_buf_item_pushbuf,
 	.iop_committing = xfs_buf_item_committing
 };
 
@@ -989,20 +938,27 @@ xfs_buf_iodone_callbacks(
 	 * If the write was asynchronous then no one will be looking for the
 	 * error.  Clear the error state and write the buffer out again.
 	 *
-	 * During sync or umount we'll write all pending buffers again
-	 * synchronous, which will catch these errors if they keep hanging
-	 * around.
+	 * XXX: This helps against transient write errors, but we need to find
+	 * a way to shut the filesystem down if the writes keep failing.
+	 *
+	 * In practice we'll shut the filesystem down soon as non-transient
+	 * erorrs tend to affect the whole device and a failing log write
+	 * will make us give up.  But we really ought to do better here.
 	 */
 	if (XFS_BUF_ISASYNC(bp)) {
+		ASSERT(bp->b_iodone != NULL);
+
+		trace_xfs_buf_item_iodone_async(bp, _RET_IP_);
+
 		xfs_buf_ioerror(bp, 0); /* errno of 0 unsets the flag */
 
 		if (!XFS_BUF_ISSTALE(bp)) {
-			xfs_buf_delwri_queue(bp);
-			XFS_BUF_DONE(bp);
+			bp->b_flags |= XBF_WRITE | XBF_ASYNC | XBF_DONE;
+			xfs_bdstrat_cb(bp);
+		} else {
+			xfs_buf_relse(bp);
 		}
-		ASSERT(bp->b_iodone != NULL);
-		trace_xfs_buf_item_iodone_async(bp, _RET_IP_);
-		xfs_buf_relse(bp);
+
 		return;
 	}
 
diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index 53757d83e4f..65b8aa37622 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -1005,39 +1005,6 @@ xfs_dqlock2(
 	}
 }
 
-/*
- * Give the buffer a little push if it is incore and
- * wait on the flush lock.
- */
-void
-xfs_dqflock_pushbuf_wait(
-	xfs_dquot_t	*dqp)
-{
-	xfs_mount_t	*mp = dqp->q_mount;
-	xfs_buf_t	*bp;
-
-	/*
-	 * Check to see if the dquot has been flushed delayed
-	 * write.  If so, grab its buffer and send it
-	 * out immediately.  We'll be able to acquire
-	 * the flush lock when the I/O completes.
-	 */
-	bp = xfs_incore(mp->m_ddev_targp, dqp->q_blkno,
-			mp->m_quotainfo->qi_dqchunklen, XBF_TRYLOCK);
-	if (!bp)
-		goto out_lock;
-
-	if (XFS_BUF_ISDELAYWRITE(bp)) {
-		if (xfs_buf_ispinned(bp))
-			xfs_log_force(mp, 0);
-		xfs_buf_delwri_promote(bp);
-		wake_up_process(bp->b_target->bt_task);
-	}
-	xfs_buf_relse(bp);
-out_lock:
-	xfs_dqflock(dqp);
-}
-
 int __init
 xfs_qm_init(void)
 {
diff --git a/fs/xfs/xfs_dquot.h b/fs/xfs/xfs_dquot.h
index 5f2a2f2c0c5..7d20af27346 100644
--- a/fs/xfs/xfs_dquot.h
+++ b/fs/xfs/xfs_dquot.h
@@ -152,7 +152,6 @@ extern int		xfs_qm_dqget(xfs_mount_t *, xfs_inode_t *,
 extern void		xfs_qm_dqput(xfs_dquot_t *);
 
 extern void		xfs_dqlock2(struct xfs_dquot *, struct xfs_dquot *);
-extern void		xfs_dqflock_pushbuf_wait(struct xfs_dquot *dqp);
 
 static inline struct xfs_dquot *xfs_qm_dqhold(struct xfs_dquot *dqp)
 {
diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c
index 8d829581427..9c5d58d24e5 100644
--- a/fs/xfs/xfs_dquot_item.c
+++ b/fs/xfs/xfs_dquot_item.c
@@ -108,46 +108,6 @@ xfs_qm_dquot_logitem_unpin(
 		wake_up(&dqp->q_pinwait);
 }
 
-/*
- * Given the logitem, this writes the corresponding dquot entry to disk
- * asynchronously. This is called with the dquot entry securely locked;
- * we simply get xfs_qm_dqflush() to do the work, and unlock the dquot
- * at the end.
- */
-STATIC void
-xfs_qm_dquot_logitem_push(
-	struct xfs_log_item	*lip)
-{
-	struct xfs_dquot	*dqp = DQUOT_ITEM(lip)->qli_dquot;
-	struct xfs_buf		*bp = NULL;
-	int			error;
-
-	ASSERT(XFS_DQ_IS_LOCKED(dqp));
-	ASSERT(!completion_done(&dqp->q_flush));
-	ASSERT(atomic_read(&dqp->q_pincount) == 0);
-
-	/*
-	 * Since we were able to lock the dquot's flush lock and
-	 * we found it on the AIL, the dquot must be dirty.  This
-	 * is because the dquot is removed from the AIL while still
-	 * holding the flush lock in xfs_dqflush_done().  Thus, if
-	 * we found it in the AIL and were able to obtain the flush
-	 * lock without sleeping, then there must not have been
-	 * anyone in the process of flushing the dquot.
-	 */
-	error = xfs_qm_dqflush(dqp, &bp);
-	if (error) {
-		xfs_warn(dqp->q_mount, "%s: push error %d on dqp %p",
-			__func__, error, dqp);
-		goto out_unlock;
-	}
-
-	xfs_buf_delwri_queue(bp);
-	xfs_buf_relse(bp);
-out_unlock:
-	xfs_dqunlock(dqp);
-}
-
 STATIC xfs_lsn_t
 xfs_qm_dquot_logitem_committed(
 	struct xfs_log_item	*lip,
@@ -179,67 +139,15 @@ xfs_qm_dqunpin_wait(
 	wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
 }
 
-/*
- * This is called when IOP_TRYLOCK returns XFS_ITEM_PUSHBUF to indicate that
- * the dquot is locked by us, but the flush lock isn't. So, here we are
- * going to see if the relevant dquot buffer is incore, waiting on DELWRI.
- * If so, we want to push it out to help us take this item off the AIL as soon
- * as possible.
- *
- * We must not be holding the AIL lock at this point. Calling incore() to
- * search the buffer cache can be a time consuming thing, and AIL lock is a
- * spinlock.
- */
-STATIC bool
-xfs_qm_dquot_logitem_pushbuf(
-	struct xfs_log_item	*lip)
-{
-	struct xfs_dq_logitem	*qlip = DQUOT_ITEM(lip);
-	struct xfs_dquot	*dqp = qlip->qli_dquot;
-	struct xfs_buf		*bp;
-	bool			ret = true;
-
-	ASSERT(XFS_DQ_IS_LOCKED(dqp));
-
-	/*
-	 * If flushlock isn't locked anymore, chances are that the
-	 * inode flush completed and the inode was taken off the AIL.
-	 * So, just get out.
-	 */
-	if (completion_done(&dqp->q_flush) ||
-	    !(lip->li_flags & XFS_LI_IN_AIL)) {
-		xfs_dqunlock(dqp);
-		return true;
-	}
-
-	bp = xfs_incore(dqp->q_mount->m_ddev_targp, qlip->qli_format.qlf_blkno,
-			dqp->q_mount->m_quotainfo->qi_dqchunklen, XBF_TRYLOCK);
-	xfs_dqunlock(dqp);
-	if (!bp)
-		return true;
-	if (XFS_BUF_ISDELAYWRITE(bp))
-		xfs_buf_delwri_promote(bp);
-	if (xfs_buf_ispinned(bp))
-		ret = false;
-	xfs_buf_relse(bp);
-	return ret;
-}
-
-/*
- * This is called to attempt to lock the dquot associated with this
- * dquot log item.  Don't sleep on the dquot lock or the flush lock.
- * If the flush lock is already held, indicating that the dquot has
- * been or is in the process of being flushed, then see if we can
- * find the dquot's buffer in the buffer cache without sleeping.  If
- * we can and it is marked delayed write, then we want to send it out.
- * We delay doing so until the push routine, though, to avoid sleeping
- * in any device strategy routines.
- */
 STATIC uint
-xfs_qm_dquot_logitem_trylock(
-	struct xfs_log_item	*lip)
+xfs_qm_dquot_logitem_push(
+	struct xfs_log_item	*lip,
+	struct list_head	*buffer_list)
 {
 	struct xfs_dquot	*dqp = DQUOT_ITEM(lip)->qli_dquot;
+	struct xfs_buf		*bp = NULL;
+	uint			rval = XFS_ITEM_SUCCESS;
+	int			error;
 
 	if (atomic_read(&dqp->q_pincount) > 0)
 		return XFS_ITEM_PINNED;
@@ -252,20 +160,36 @@ xfs_qm_dquot_logitem_trylock(
 	 * taking the quota lock.
 	 */
 	if (atomic_read(&dqp->q_pincount) > 0) {
-		xfs_dqunlock(dqp);
-		return XFS_ITEM_PINNED;
+		rval = XFS_ITEM_PINNED;
+		goto out_unlock;
 	}
 
+	/*
+	 * Someone else is already flushing the dquot.  Nothing we can do
+	 * here but wait for the flush to finish and remove the item from
+	 * the AIL.
+	 */
 	if (!xfs_dqflock_nowait(dqp)) {
-		/*
-		 * dquot has already been flushed to the backing buffer,
-		 * leave it locked, pushbuf routine will unlock it.
-		 */
-		return XFS_ITEM_PUSHBUF;
+		rval = XFS_ITEM_FLUSHING;
+		goto out_unlock;
+	}
+
+	spin_unlock(&lip->li_ailp->xa_lock);
+
+	error = xfs_qm_dqflush(dqp, &bp);
+	if (error) {
+		xfs_warn(dqp->q_mount, "%s: push error %d on dqp %p",
+			__func__, error, dqp);
+	} else {
+		if (!xfs_buf_delwri_queue(bp, buffer_list))
+			rval = XFS_ITEM_FLUSHING;
+		xfs_buf_relse(bp);
 	}
 
-	ASSERT(lip->li_flags & XFS_LI_IN_AIL);
-	return XFS_ITEM_SUCCESS;
+	spin_lock(&lip->li_ailp->xa_lock);
+out_unlock:
+	xfs_dqunlock(dqp);
+	return rval;
 }
 
 /*
@@ -316,11 +240,9 @@ static const struct xfs_item_ops xfs_dquot_item_ops = {
 	.iop_format	= xfs_qm_dquot_logitem_format,
 	.iop_pin	= xfs_qm_dquot_logitem_pin,
 	.iop_unpin	= xfs_qm_dquot_logitem_unpin,
-	.iop_trylock	= xfs_qm_dquot_logitem_trylock,
 	.iop_unlock	= xfs_qm_dquot_logitem_unlock,
 	.iop_committed	= xfs_qm_dquot_logitem_committed,
 	.iop_push	= xfs_qm_dquot_logitem_push,
-	.iop_pushbuf	= xfs_qm_dquot_logitem_pushbuf,
 	.iop_committing = xfs_qm_dquot_logitem_committing
 };
 
@@ -415,11 +337,13 @@ xfs_qm_qoff_logitem_unpin(
 }
 
 /*
- * Quotaoff items have no locking, so just return success.
+ * There isn't much you can do to push a quotaoff item.  It is simply
+ * stuck waiting for the log to be flushed to disk.
  */
 STATIC uint
-xfs_qm_qoff_logitem_trylock(
-	struct xfs_log_item	*lip)
+xfs_qm_qoff_logitem_push(
+	struct xfs_log_item	*lip,
+	struct list_head	*buffer_list)
 {
 	return XFS_ITEM_LOCKED;
 }
@@ -446,17 +370,6 @@ xfs_qm_qoff_logitem_committed(
 	return lsn;
 }
 
-/*
- * There isn't much you can do to push on an quotaoff item.  It is simply
- * stuck waiting for the log to be flushed to disk.
- */
-STATIC void
-xfs_qm_qoff_logitem_push(
-	struct xfs_log_item	*lip)
-{
-}
-
-
 STATIC xfs_lsn_t
 xfs_qm_qoffend_logitem_committed(
 	struct xfs_log_item	*lip,
@@ -504,7 +417,6 @@ static const struct xfs_item_ops xfs_qm_qoffend_logitem_ops = {
 	.iop_fo