xfs: only look at the fork format in xfs_idestroy_fork

Stop using the XFS_IFEXTENTS flag, and instead switch on the fork format
in xfs_idestroy_fork to decide how to cleanup.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

fs/xfs/libxfs/xfs_inode_fork.c

@@ -522,17 +522,16 @@ xfs_idestroy_fork(
 		ifp->if_broot = NULL;
 	}
 
-	/*
-	 * If the format is local, then we can't have an extents array so just
-	 * look for an inline data array.  If we're not local then we may or may
-	 * not have an extents list, so check and free it up if we do.
-	 */
-	if (ifp->if_format == XFS_DINODE_FMT_LOCAL) {
+	switch (ifp->if_format) {
+	case XFS_DINODE_FMT_LOCAL:
 		kmem_free(ifp->if_u1.if_data);
 		ifp->if_u1.if_data = NULL;
-	} else if (ifp->if_flags & XFS_IFEXTENTS) {
+		break;
+	case XFS_DINODE_FMT_EXTENTS:
+	case XFS_DINODE_FMT_BTREE:
 		if (ifp->if_height)
 			xfs_iext_destroy(ifp);
+		break;
 	}
 }