diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3fd6c9aed7191..f58e03d1775d8 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1255,6 +1255,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
 	u64 page_start;
 	u64 page_end;
 	u64 page_cnt;
+	u64 start = (u64)start_index << PAGE_SHIFT;
 	int ret;
 	int i;
 	int i_done;
@@ -1271,8 +1272,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
 	page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
 
 	ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
-			start_index << PAGE_SHIFT,
-			page_cnt << PAGE_SHIFT);
+			start, page_cnt << PAGE_SHIFT);
 	if (ret)
 		return ret;
 	i_done = 0;
@@ -1361,8 +1361,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
 		btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
 		spin_unlock(&BTRFS_I(inode)->lock);
 		btrfs_delalloc_release_space(inode, data_reserved,
-				start_index << PAGE_SHIFT,
-				(page_cnt - i_done) << PAGE_SHIFT, true);
+				start, (page_cnt - i_done) << PAGE_SHIFT, true);
 	}
 
 
@@ -1389,8 +1388,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
 		put_page(pages[i]);
 	}
 	btrfs_delalloc_release_space(inode, data_reserved,
-			start_index << PAGE_SHIFT,
-			page_cnt << PAGE_SHIFT, true);
+			start, page_cnt << PAGE_SHIFT, true);
 	btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT);
 	extent_changeset_free(data_reserved);
 	return ret;