Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[linux.git] / fs / xfs / xfs_ondisk.h

diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index d3e04d20d8d45007279ee85ab5b04833d3f9355a..c8ba98fae30aefa7013ebfa168fed652a955f3e7 100644 (file)
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -125,6 +125,27 @@ xfs_check_ondisk_structs(void)
        XFS_CHECK_STRUCT_SIZE(struct xfs_inode_log_format,      56);
        XFS_CHECK_STRUCT_SIZE(struct xfs_qoff_logformat,        20);
        XFS_CHECK_STRUCT_SIZE(struct xfs_trans_header,          16);
+
+       /*
+        * The v5 superblock format extended several v4 header structures with
+        * additional data. While new fields are only accessible on v5
+        * superblocks, it's important that the v5 structures place original v4
+        * fields/headers in the correct location on-disk. For example, we must
+        * be able to find magic values at the same location in certain blocks
+        * regardless of superblock version.
+        *
+        * The following checks ensure that various v5 data structures place the
+        * subset of v4 metadata associated with the same type of block at the
+        * start of the on-disk block. If there is no data structure definition
+        * for certain types of v4 blocks, traverse down to the first field of
+        * common metadata (e.g., magic value) and make sure it is at offset
+        * zero.
+        */
+       XFS_CHECK_OFFSET(struct xfs_dir3_leaf, hdr.info.hdr,    0);
+       XFS_CHECK_OFFSET(struct xfs_da3_intnode, hdr.info.hdr,  0);
+       XFS_CHECK_OFFSET(struct xfs_dir3_data_hdr, hdr.magic,   0);
+       XFS_CHECK_OFFSET(struct xfs_dir3_free, hdr.hdr.magic,   0);
+       XFS_CHECK_OFFSET(struct xfs_attr3_leafblock, hdr.info.hdr, 0);
 }
 
 #endif /* __XFS_ONDISK_H */