[PATCH] xfs: check sizes of XFS on-disk structures at compile time

Darrick J. Wong
2016-01-11T23:27:04Z

Check the sizes of XFS on-disk structures when compiling the kernel.
Use this to catch inadvertent changes in structure size due to padding
and alignment issues, etc.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_format.h | 4 ++++
fs/xfs/xfs_super.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 49 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index e2536bb..a589b47 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -1509,4 +1509,8 @@ struct xfs_acl {
#define SGI_ACL_FILE_SIZE (sizeof(SGI_ACL_FILE)-1)
#define SGI_ACL_DEFAULT_SIZE (sizeof(SGI_ACL_DEFAULT)-1)

+#define XFS_CHECK_STRUCT_SIZE(structname, size) \
+ BUILD_BUG_ON_MSG(sizeof(structname) != (size), "XFS: sizeof(struct " \
+ #structname ") is wrong, expected " #size)
+
#endif /* __XFS_FORMAT_H__ */
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 36bd882..31b69d1 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1812,11 +1812,56 @@ xfs_destroy_workqueues(void)
destroy_workqueue(xfs_alloc_wq);
}

+static void __init
+xfs_check_ondisk_structs(void)
+{
+ /* on-disk structures */
+ XFS_CHECK_STRUCT_SIZE(struct xfs_dsb, 264);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_agf, 224);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_agi, 336);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_agfl, 36);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_timestamp, 8);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_dinode, 176);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_disk_dquot, 104);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_dqblk, 136);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_dsymlink_hdr, 56);
+ XFS_CHECK_STRUCT_SIZE(xfs_alloc_rec_t, 8);
+ XFS_CHECK_STRUCT_SIZE(xfs_alloc_key_t, 8);
+ XFS_CHECK_STRUCT_SIZE(xfs_alloc_ptr_t, 4);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_inobt_rec, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_inobt_key, 4);
+ XFS_CHECK_STRUCT_SIZE(xfs_inobt_ptr_t, 4);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_bmdr_block, 4);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_rec, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_key, 8);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_btree_block, 72);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_acl_entry, 12);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_acl, 4);
+
+ /* log structures */
+ XFS_CHECK_STRUCT_SIZE(struct xfs_trans_header, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_inode_log_format_32, 52);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_inode_log_format_64, 56);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_ictimestamp, 8);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_icdinode, 176);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_extent_32, 12);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_extent_64, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 28);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 32);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 28);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 32);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_dq_logformat, 24);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_qoff_logformat, 20);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_icreate_log, 28);
+}
+
STATIC int __init
init_xfs_fs(void)
{
int error;

+ xfs_check_ondisk_structs();
+
printk(KERN_INFO XFS_VERSION_STRING " with "
XFS_BUILD_OPTIONS " enabled\n");