Btrfs: pass fs_info to btrfs_map_block() instead of mapping_tree

This is required for the device replace procedure in a later step.
Two calling functions also had to be changed to have the fs_info
pointer: repair_io_failure() and scrub_setup_recheck_block().

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index a955669..0ddc565 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -323,7 +323,6 @@
 	struct reada_extent *re = NULL;
 	struct reada_extent *re_exist = NULL;
 	struct btrfs_fs_info *fs_info = root->fs_info;
-	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
 	struct btrfs_bio *bbio = NULL;
 	struct btrfs_device *dev;
 	struct btrfs_device *prev_dev;
@@ -358,7 +357,7 @@
 	 * map block
 	 */
 	length = blocksize;
-	ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length, &bbio, 0);
+	ret = btrfs_map_block(fs_info, REQ_WRITE, logical, &length, &bbio, 0);
 	if (ret || !bbio || length < blocksize)
 		goto error;