btrfs: btrfs_defrag_root() doesn't defrag extent root tree

Since btrfs_defrag_leaves() does not support extent_root, remove its
corresponding call. The user can use the file based defrag to defrag
extents as of now.

No change in behaviour as extent_root is explicitly skipped in
btrfs_defrag_leaves and this has never worked as expected.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
[ ehnance changelong ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/ioctl.c

@@ -2613,9 +2613,6 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
 			goto out;
 		}
 		ret = btrfs_defrag_root(root);
-		if (ret)
-			goto out;
-		ret = btrfs_defrag_root(root->fs_info->extent_root);
 		break;
 	case S_IFREG:
 		if (!(file->f_mode & FMODE_WRITE)) {