Btrfs: fix wrong file extent length

There are two types of the file extent - inline extent and regular extent,
When we log file extents, we didn't take inline extent into account, fix it.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

fs/btrfs/file-item.c

@@ -133,7 +133,6 @@ fail:
 	return ERR_PTR(ret);
 }
 
-
 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root,
 			     struct btrfs_path *path, u64 objectid,
@@ -151,6 +150,26 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
+u64 btrfs_file_extent_length(struct btrfs_path *path)
+{
+	int extent_type;
+	struct btrfs_file_extent_item *fi;
+	u64 len;
+
+	fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
+			    struct btrfs_file_extent_item);
+	extent_type = btrfs_file_extent_type(path->nodes[0], fi);
+
+	if (extent_type == BTRFS_FILE_EXTENT_REG ||
+	    extent_type == BTRFS_FILE_EXTENT_PREALLOC)
+		len = btrfs_file_extent_num_bytes(path->nodes[0], fi);
+	else if (extent_type == BTRFS_FILE_EXTENT_INLINE)
+		len = btrfs_file_extent_inline_len(path->nodes[0], fi);
+	else
+		BUG();
+
+	return len;
+}
 
 static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
 				   struct inode *inode, struct bio *bio,