2 files changed, 25 insertions, 44 deletions

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 051c7fe..cd8ecb7 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -775,7 +775,6 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 	struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 	u64 disk_i_size;
 	u64 new_i_size;
-	u64 i_size_test;
 	u64 i_size = i_size_read(inode);
 	struct rb_node *node;
 	struct rb_node *prev = NULL;
@@ -835,55 +834,30 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 			break;
 		if (test->file_offset >= i_size)
 			break;
-		if (test->file_offset >= disk_i_size)
+		if (test->file_offset >= disk_i_size) {
+			/*
+			 * we don't update disk_i_size now, so record this
+			 * undealt i_size. Or we will not know the real
+			 * i_size.
+			 */
+			if (test->outstanding_isize < offset)
+				test->outstanding_isize = offset;
+			if (ordered &&
+			    ordered->outstanding_isize >
+			    test->outstanding_isize)
+				test->outstanding_isize =
+						ordered->outstanding_isize;
 			goto out;
-	}
-	new_i_size = min_t(u64, offset, i_size);
-
-	/*
-	 * at this point, we know we can safely update i_size to at least
-	 * the offset from this ordered extent.  But, we need to
-	 * walk forward and see if ios from higher up in the file have
-	 * finished.
-	 */
-	if (ordered) {
-		node = rb_next(&ordered->rb_node);
-	} else {
-		if (prev)
-			node = rb_next(prev);
-		else
-			node = rb_first(&tree->tree);
-	}
-
-	/*
-	 * We are looking for an area between our current extent and the next
-	 * ordered extent to update the i_size to.  There are 3 cases here
-	 *
-	 * 1) We don't actually have anything and we can update to i_size.
-	 * 2) We have stuff but they already did their i_size update so again we
-	 * can just update to i_size.
-	 * 3) We have an outstanding ordered extent so the most we can update
-	 * our disk_i_size to is the start of the next offset.
-	 */
-	i_size_test = i_size;
-	for (; node; node = rb_next(node)) {
-		test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
-
-		if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
-			continue;
-		if (test->file_offset > offset) {
-			i_size_test = test->file_offset;
-			break;
 		}
 	}
+	new_i_size = min_t(u64, offset, i_size);
 
 	/*
-	 * i_size_test is the end of a region after this ordered
-	 * extent where there are no ordered extents, we can safely set
-	 * disk_i_size to this.
+	 * Some ordered extents may completed before the current one, and
+	 * we hold the real i_size in ->outstanding_isize.
 	 */
-	if (i_size_test > offset)
-		new_i_size = min_t(u64, i_size_test, i_size);
+	if (ordered && ordered->outstanding_isize > new_i_size)
+		new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
 	BTRFS_I(inode)->disk_i_size = new_i_size;
 	ret = 0;
 out:
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index e03c560..c2443a4 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -96,6 +96,13 @@ struct btrfs_ordered_extent {
 	/* number of bytes that still need writing */
 	u64 bytes_left;
 
+	/*
+	 * the end of the ordered extent which is behind it but
+	 * didn't update disk_i_size. Please see the comment of
+	 * btrfs_ordered_update_i_size();
+	 */
+	u64 outstanding_isize;
+
 	/* flags (described above) */
 	unsigned long flags;