1 files changed, 245 insertions, 45 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 6f3ebb6..6f76ba8 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -33,6 +33,7 @@
 #include <linux/migrate.h>
 #include <linux/backing-dev.h>
 #include <linux/freezer.h>
+#include <linux/list_sort.h>
 
 #include "xfs_sb.h"
 #include "xfs_inum.h"
@@ -1072,22 +1073,30 @@ xfs_buf_ioerror(
 }
 
 int
-xfs_bawrite(
-	void			*mp,
+xfs_bwrite(
+	struct xfs_mount	*mp,
 	struct xfs_buf		*bp)
 {
-	trace_xfs_buf_bawrite(bp, _RET_IP_);
+	int			iowait = (bp->b_flags & XBF_ASYNC) == 0;
+	int			error = 0;
 
-	ASSERT(bp->b_bn != XFS_BUF_DADDR_NULL);
+	bp->b_strat = xfs_bdstrat_cb;
+	bp->b_mount = mp;
+	bp->b_flags |= XBF_WRITE;
+	if (!iowait)
+		bp->b_flags |= _XBF_RUN_QUEUES;
 
 	xfs_buf_delwri_dequeue(bp);
+	xfs_buf_iostrategy(bp);
 
-	bp->b_flags &= ~(XBF_READ | XBF_DELWRI | XBF_READ_AHEAD);
-	bp->b_flags |= (XBF_WRITE | XBF_ASYNC | _XBF_RUN_QUEUES);
+	if (iowait) {
+		error = xfs_buf_iowait(bp);
+		if (error)
+			xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
+		xfs_buf_relse(bp);
+	}
 
-	bp->b_mount = mp;
-	bp->b_strat = xfs_bdstrat_cb;
-	return xfs_bdstrat_cb(bp);
+	return error;
 }
 
 void
@@ -1106,6 +1115,126 @@ xfs_bdwrite(
 	xfs_buf_delwri_queue(bp, 1);
 }
 
+/*
+ * Called when we want to stop a buffer from getting written or read.
+ * We attach the EIO error, muck with its flags, and call biodone
+ * so that the proper iodone callbacks get called.
+ */
+STATIC int
+xfs_bioerror(
+	xfs_buf_t *bp)
+{
+#ifdef XFSERRORDEBUG
+	ASSERT(XFS_BUF_ISREAD(bp) || bp->b_iodone);
+#endif
+
+	/*
+	 * No need to wait until the buffer is unpinned, we aren't flushing it.
+	 */
+	XFS_BUF_ERROR(bp, EIO);
+
+	/*
+	 * We're calling biodone, so delete XBF_DONE flag.
+	 */
+	XFS_BUF_UNREAD(bp);
+	XFS_BUF_UNDELAYWRITE(bp);
+	XFS_BUF_UNDONE(bp);
+	XFS_BUF_STALE(bp);
+
+	XFS_BUF_CLR_BDSTRAT_FUNC(bp);
+	xfs_biodone(bp);
+
+	return EIO;
+}
+
+/*
+ * Same as xfs_bioerror, except that we are releasing the buffer
+ * here ourselves, and avoiding the biodone call.
+ * This is meant for userdata errors; metadata bufs come with
+ * iodone functions attached, so that we can track down errors.
+ */
+STATIC int
+xfs_bioerror_relse(
+	struct xfs_buf	*bp)
+{
+	int64_t		fl = XFS_BUF_BFLAGS(bp);
+	/*
+	 * No need to wait until the buffer is unpinned.
+	 * We aren't flushing it.
+	 *
+	 * chunkhold expects B_DONE to be set, whether
+	 * we actually finish the I/O or not. We don't want to
+	 * change that interface.
+	 */
+	XFS_BUF_UNREAD(bp);
+	XFS_BUF_UNDELAYWRITE(bp);
+	XFS_BUF_DONE(bp);
+	XFS_BUF_STALE(bp);
+	XFS_BUF_CLR_IODONE_FUNC(bp);
+	XFS_BUF_CLR_BDSTRAT_FUNC(bp);
+	if (!(fl & XBF_ASYNC)) {
+		/*
+		 * Mark b_error and B_ERROR _both_.
+		 * Lot's of chunkcache code assumes that.
+		 * There's no reason to mark error for
+		 * ASYNC buffers.
+		 */
+		XFS_BUF_ERROR(bp, EIO);
+		XFS_BUF_FINISH_IOWAIT(bp);
+	} else {
+		xfs_buf_relse(bp);
+	}
+
+	return EIO;
+}
+
+
+/*
+ * All xfs metadata buffers except log state machine buffers
+ * get this attached as their b_bdstrat callback function.
+ * This is so that we can catch a buffer
+ * after prematurely unpinning it to forcibly shutdown the filesystem.
+ */
+int
+xfs_bdstrat_cb(
+	struct xfs_buf	*bp)
+{
+	if (XFS_FORCED_SHUTDOWN(bp->b_mount)) {
+		trace_xfs_bdstrat_shut(bp, _RET_IP_);
+		/*
+		 * Metadata write that didn't get logged but
+		 * written delayed anyway. These aren't associated
+		 * with a transaction, and can be ignored.
+		 */
+		if (!bp->b_iodone && !XFS_BUF_ISREAD(bp))
+			return xfs_bioerror_relse(bp);
+		else
+			return xfs_bioerror(bp);
+	}
+
+	xfs_buf_iorequest(bp);
+	return 0;
+}
+
+/*
+ * Wrapper around bdstrat so that we can stop data from going to disk in case
+ * we are shutting down the filesystem.  Typically user data goes thru this
+ * path; one of the exceptions is the superblock.
+ */
+void
+xfsbdstrat(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp)
+{
+	if (XFS_FORCED_SHUTDOWN(mp)) {
+		trace_xfs_bdstrat_shut(bp, _RET_IP_);
+		xfs_bioerror_relse(bp);
+		return;
+	}
+
+	xfs_buf_iorequest(bp);
+}
+
 STATIC void
 _xfs_buf_ioend(
 	xfs_buf_t		*bp,
@@ -1324,7 +1453,7 @@ xfs_buf_iomove(
 	xfs_buf_t		*bp,	/* buffer to process		*/
 	size_t			boff,	/* starting buffer offset	*/
 	size_t			bsize,	/* length to copy		*/
-	caddr_t			data,	/* data address			*/
+	void			*data,	/* data address			*/
 	xfs_buf_rw_t		mode)	/* read/write/zero flag		*/
 {
 	size_t			bend, cpoff, csize;
@@ -1406,8 +1535,8 @@ xfs_alloc_bufhash(
 
 	btp->bt_hashshift = external ? 3 : 8;	/* 8 or 256 buckets */
 	btp->bt_hashmask = (1 << btp->bt_hashshift) - 1;
-	btp->bt_hash = kmem_zalloc((1 << btp->bt_hashshift) *
-					sizeof(xfs_bufhash_t), KM_SLEEP | KM_LARGE);
+	btp->bt_hash = kmem_zalloc_large((1 << btp->bt_hashshift) *
+					 sizeof(xfs_bufhash_t));
 	for (i = 0; i < (1 << btp->bt_hashshift); i++) {
 		spin_lock_init(&btp->bt_hash[i].bh_lock);
 		INIT_LIST_HEAD(&btp->bt_hash[i].bh_list);
@@ -1418,7 +1547,7 @@ STATIC void
 xfs_free_bufhash(
 	xfs_buftarg_t		*btp)
 {
-	kmem_free(btp->bt_hash);
+	kmem_free_large(btp->bt_hash);
 	btp->bt_hash = NULL;
 }
 
@@ -1623,6 +1752,11 @@ xfs_buf_delwri_queue(
 		list_del(&bp->b_list);
 	}
 
+	if (list_empty(dwq)) {
+		/* start xfsbufd as it is about to have something to do */
+		wake_up_process(bp->b_target->bt_task);
+	}
+
 	bp->b_flags |= _XBF_DELWRI_Q;
 	list_add_tail(&bp->b_list, dwq);
 	bp->b_queuetime = jiffies;
@@ -1654,6 +1788,35 @@ xfs_buf_delwri_dequeue(
 	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);
+
+	/*
+	 * 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 (bp->b_queuetime < jiffies - age)
+		return;
+	bp->b_queuetime = jiffies - age;
+	spin_lock(&btp->bt_delwrite_lock);
+	list_move(&bp->b_list, &btp->bt_delwrite_queue);
+	spin_unlock(&btp->bt_delwrite_lock);
+}
+
 STATIC void
 xfs_buf_runall_queues(
 	struct workqueue_struct	*queue)
@@ -1672,6 +1835,8 @@ xfsbufd_wakeup(
 	list_for_each_entry(btp, &xfs_buftarg_list, bt_list) {
 		if (test_bit(XBT_FORCE_SLEEP, &btp->bt_flags))
 			continue;
+		if (list_empty(&btp->bt_delwrite_queue))
+			continue;
 		set_bit(XBT_FORCE_FLUSH, &btp->bt_flags);
 		wake_up_process(btp->bt_task);
 	}
@@ -1722,20 +1887,53 @@ xfs_buf_delwri_split(
 
 }
 
+/*
+ * Compare function is more complex than it needs to be because
+ * the return value is only 32 bits and we are doing comparisons
+ * on 64 bit values
+ */
+static int
+xfs_buf_cmp(
+	void		*priv,
+	struct list_head *a,
+	struct list_head *b)
+{
+	struct xfs_buf	*ap = container_of(a, struct xfs_buf, b_list);
+	struct xfs_buf	*bp = container_of(b, struct xfs_buf, b_list);
+	xfs_daddr_t		diff;
+
+	diff = ap->b_bn - bp->b_bn;
+	if (diff < 0)
+		return -1;
+	if (diff > 0)
+		return 1;
+	return 0;
+}
+
+void
+xfs_buf_delwri_sort(
+	xfs_buftarg_t	*target,
+	struct list_head *list)
+{
+	list_sort(NULL, list, xfs_buf_cmp);
+}
+
 STATIC int
 xfsbufd(
 	void		*data)
 {
-	struct list_head tmp;
-	xfs_buftarg_t	*target = (xfs_buftarg_t *)data;
-	int		count;
-	xfs_buf_t	*bp;
+	xfs_buftarg_t   *target = (xfs_buftarg_t *)data;
 
 	current->flags |= PF_MEMALLOC;
 
 	set_freezable();
 
 	do {
+		long	age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
+		long	tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10);
+		int	count = 0;
+		struct list_head tmp;
+
 		if (unlikely(freezing(current))) {
 			set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
 			refrigerator();
@@ -1743,17 +1941,16 @@ xfsbufd(
 			clear_bit(XBT_FORCE_SLEEP, &target->bt_flags);
 		}
 
-		schedule_timeout_interruptible(
-			xfs_buf_timer_centisecs * msecs_to_jiffies(10));
+		/* sleep for a long time if there is nothing to do. */
+		if (list_empty(&target->bt_delwrite_queue))
+			tout = MAX_SCHEDULE_TIMEOUT;
+		schedule_timeout_interruptible(tout);
 
-		xfs_buf_delwri_split(target, &tmp,
-				xfs_buf_age_centisecs * msecs_to_jiffies(10));
-
-		count = 0;
+		xfs_buf_delwri_split(target, &tmp, age);
+		list_sort(NULL, &tmp, xfs_buf_cmp);
 		while (!list_empty(&tmp)) {
-			bp = list_entry(tmp.next, xfs_buf_t, b_list);
-			ASSERT(target == bp->b_target);
-
+			struct xfs_buf *bp;
+			bp = list_first_entry(&tmp, struct xfs_buf, b_list);
 			list_del_init(&bp->b_list);
 			xfs_buf_iostrategy(bp);
 			count++;
@@ -1779,42 +1976,45 @@ xfs_flush_buftarg(
 	xfs_buftarg_t	*target,
 	int		wait)
 {
-	struct list_head tmp;
-	xfs_buf_t	*bp, *n;
+	xfs_buf_t	*bp;
 	int		pincount = 0;
+	LIST_HEAD(tmp_list);
+	LIST_HEAD(wait_list);
 
 	xfs_buf_runall_queues(xfsconvertd_workqueue);
 	xfs_buf_runall_queues(xfsdatad_workqueue);
 	xfs_buf_runall_queues(xfslogd_workqueue);
 
 	set_bit(XBT_FORCE_FLUSH, &target->bt_flags);
-	pincount = xfs_buf_delwri_split(target, &tmp, 0);
+	pincount = xfs_buf_delwri_split(target, &tmp_list, 0);
 
 	/*
-	 * Dropped the delayed write list lock, now walk the temporary list
+	 * 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_for_each_entry_safe(bp, n, &tmp, b_list) {
+	list_sort(NULL, &tmp_list, xfs_buf_cmp);
+	while (!list_empty(&tmp_list)) {
+		bp = list_first_entry(&tmp_list, struct xfs_buf, b_list);
 		ASSERT(target == bp->b_target);
-		if (wait)
+		list_del_init(&bp->b_list);
+		if (wait) {
 			bp->b_flags &= ~XBF_ASYNC;
-		else
-			list_del_init(&bp->b_list);
-
+			list_add(&bp->b_list, &wait_list);
+		}
 		xfs_buf_iostrategy(bp);
 	}
 
-	if (wait)
+	if (wait) {
+		/* Expedite and wait for IO to complete. */
 		blk_run_address_space(target->bt_mapping);
+		while (!list_empty(&wait_list)) {
+			bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
 
-	/*
-	 * Remaining list items must be flushed before returning
-	 */
-	while (!list_empty(&tmp)) {
-		bp = list_entry(tmp.next, xfs_buf_t, b_list);
-
-		list_del_init(&bp->b_list);
-		xfs_iowait(bp);
-		xfs_buf_relse(bp);
+			list_del_init(&bp->b_list);
+			xfs_iowait(bp);
+			xfs_buf_relse(bp);
+		}
 	}
 
 	return pincount;