reverted:
--- b/libxfs/xfs_format.h
+++ a/libxfs/xfs_format.h
@@ -787,7 +787,7 @@
 	__be64		agfl_lsn;
 	__be32		agfl_crc;
 	__be32		agfl_bno[];	/* actually XFS_AGFL_SIZE(mp) */
+} xfs_agfl_t;
-} __attribute__((packed)) xfs_agfl_t;
 
 #define XFS_AGFL_CRC_OFF	offsetof(struct xfs_agfl, agfl_crc)