1 files changed, 86 insertions, 0 deletions

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index f5800620c78c..09ac1bb4c2b7 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -237,6 +237,7 @@ STATIC void
 xfs_end_ioend(
 	struct xfs_ioend	*ioend)
 {
+	struct list_head	ioend_list;
 	struct xfs_inode	*ip = XFS_I(ioend->io_inode);
 	xfs_off_t		offset = ioend->io_offset;
 	size_t			size = ioend->io_size;
@@ -273,7 +274,89 @@ xfs_end_ioend(
 done:
 	if (ioend->io_append_trans)
 		error = xfs_setfilesize_ioend(ioend, error);
+	list_replace_init(&ioend->io_list, &ioend_list);
 	xfs_destroy_ioend(ioend, error);
+
+	while (!list_empty(&ioend_list)) {
+		ioend = list_first_entry(&ioend_list, struct xfs_ioend,
+				io_list);
+		list_del_init(&ioend->io_list);
+		xfs_destroy_ioend(ioend, error);
+	}
+}
+
+/*
+ * We can merge two adjacent ioends if they have the same set of work to do.
+ */
+static bool
+xfs_ioend_can_merge(
+	struct xfs_ioend	*ioend,
+	int			ioend_error,
+	struct xfs_ioend	*next)
+{
+	int			next_error;
+
+	next_error = blk_status_to_errno(next->io_bio->bi_status);
+	if (ioend_error != next_error)
+		return false;
+	if ((ioend->io_fork == XFS_COW_FORK) ^ (next->io_fork == XFS_COW_FORK))
+		return false;
+	if ((ioend->io_state == XFS_EXT_UNWRITTEN) ^
+	    (next->io_state == XFS_EXT_UNWRITTEN))
+		return false;
+	if (ioend->io_offset + ioend->io_size != next->io_offset)
+		return false;
+	if (xfs_ioend_is_append(ioend) != xfs_ioend_is_append(next))
+		return false;
+	return true;
+}
+
+/* Try to merge adjacent completions. */
+STATIC void
+xfs_ioend_try_merge(
+	struct xfs_ioend	*ioend,
+	struct list_head	*more_ioends)
+{
+	struct xfs_ioend	*next_ioend;
+	int			ioend_error;
+	int			error;
+
+	if (list_empty(more_ioends))
+		return;
+
+	ioend_error = blk_status_to_errno(ioend->io_bio->bi_status);
+
+	while (!list_empty(more_ioends)) {
+		next_ioend = list_first_entry(more_ioends, struct xfs_ioend,
+				io_list);
+		if (!xfs_ioend_can_merge(ioend, ioend_error, next_ioend))
+			break;
+		list_move_tail(&next_ioend->io_list, &ioend->io_list);
+		ioend->io_size += next_ioend->io_size;
+		if (ioend->io_append_trans) {
+			error = xfs_setfilesize_ioend(next_ioend, 1);
+			ASSERT(error == 1);
+		}
+	}
+}
+
+/* list_sort compare function for ioends */
+static int
+xfs_ioend_compare(
+	void			*priv,
+	struct list_head	*a,
+	struct list_head	*b)
+{
+	struct xfs_ioend	*ia;
+	struct xfs_ioend	*ib;
+
+	ia = container_of(a, struct xfs_ioend, io_list);
+	ib = container_of(b, struct xfs_ioend, io_list);
+	if (ia->io_offset < ib->io_offset)
+		return -1;
+	else if (ia->io_offset > ib->io_offset)
+		return 1;
+	return 0;
 }
 
 /* Finish all pending io completions. */
@@ -292,10 +375,13 @@ xfs_end_io(
 	list_replace_init(&ip->i_ioend_list, &completion_list);
 	spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
 
+	list_sort(NULL, &completion_list, xfs_ioend_compare);
+
 	while (!list_empty(&completion_list)) {
 		ioend = list_first_entry(&completion_list, struct xfs_ioend,
 				io_list);
 		list_del_init(&ioend->io_list);
+		xfs_ioend_try_merge(ioend, &completion_list);
 		xfs_end_ioend(ioend);
 	}
 }