xfs: remove the magic numbers in xfs_btree_block-related len macros
replace the magic numbers by offsetof(...) and sizeof(...), and add two
extra checks on xfs_check_ondisk_structs()
[dchinner: renamed header structures to be more descriptive]
Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index dc97eb21..adb204d 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -1435,41 +1435,57 @@
* with the crc feature bit, and all accesses to them must be conditional on
* that flag.
*/
+/* short form block header */
+struct xfs_btree_block_shdr {
+ __be32 bb_leftsib;
+ __be32 bb_rightsib;
+
+ __be64 bb_blkno;
+ __be64 bb_lsn;
+ uuid_t bb_uuid;
+ __be32 bb_owner;
+ __le32 bb_crc;
+};
+
+/* long form block header */
+struct xfs_btree_block_lhdr {
+ __be64 bb_leftsib;
+ __be64 bb_rightsib;
+
+ __be64 bb_blkno;
+ __be64 bb_lsn;
+ uuid_t bb_uuid;
+ __be64 bb_owner;
+ __le32 bb_crc;
+ __be32 bb_pad; /* padding for alignment */
+};
+
struct xfs_btree_block {
__be32 bb_magic; /* magic number for block type */
__be16 bb_level; /* 0 is a leaf */
__be16 bb_numrecs; /* current # of data records */
union {
- struct {
- __be32 bb_leftsib;
- __be32 bb_rightsib;
-
- __be64 bb_blkno;
- __be64 bb_lsn;
- uuid_t bb_uuid;
- __be32 bb_owner;
- __le32 bb_crc;
- } s; /* short form pointers */
- struct {
- __be64 bb_leftsib;
- __be64 bb_rightsib;
-
- __be64 bb_blkno;
- __be64 bb_lsn;
- uuid_t bb_uuid;
- __be64 bb_owner;
- __le32 bb_crc;
- __be32 bb_pad; /* padding for alignment */
- } l; /* long form pointers */
+ struct xfs_btree_block_shdr s;
+ struct xfs_btree_block_lhdr l;
} bb_u; /* rest */
};
-#define XFS_BTREE_SBLOCK_LEN 16 /* size of a short form block */
-#define XFS_BTREE_LBLOCK_LEN 24 /* size of a long form block */
+/* size of a short form block */
+#define XFS_BTREE_SBLOCK_LEN \
+ (offsetof(struct xfs_btree_block, bb_u) + \
+ offsetof(struct xfs_btree_block_shdr, bb_blkno))
+/* size of a long form block */
+#define XFS_BTREE_LBLOCK_LEN \
+ (offsetof(struct xfs_btree_block, bb_u) + \
+ offsetof(struct xfs_btree_block_lhdr, bb_blkno))
/* sizes of CRC enabled btree blocks */
-#define XFS_BTREE_SBLOCK_CRC_LEN (XFS_BTREE_SBLOCK_LEN + 40)
-#define XFS_BTREE_LBLOCK_CRC_LEN (XFS_BTREE_LBLOCK_LEN + 48)
+#define XFS_BTREE_SBLOCK_CRC_LEN \
+ (offsetof(struct xfs_btree_block, bb_u) + \
+ sizeof(struct xfs_btree_block_shdr))
+#define XFS_BTREE_LBLOCK_CRC_LEN \
+ (offsetof(struct xfs_btree_block, bb_u) + \
+ sizeof(struct xfs_btree_block_lhdr))
#define XFS_BTREE_SBLOCK_CRC_OFF \
offsetof(struct xfs_btree_block, bb_u.s.bb_crc)