On Tue, Mar 29, 2016 at 08:59:23AM +1100, Dave Chinner wrote: > On Sun, Mar 27, 2016 at 02:43:24PM +0200, Geert Uytterhoeven wrote: > > On Sun, Mar 27, 2016 at 2:39 PM, Geert Uytterhoeven > > <geert@xxxxxxxxxxxxxx> wrote: > > > Below is the list of build error/warning regressions/improvements in > > > v4.6-rc1[1] compared to v4.5[2]. > > > > > > Summarized: > > > - build errors: +9/-6 > > > > > [1] http://kisskb.ellerman.id.au/kisskb/head/10114/ (all 262 configs) > > > [2] http://kisskb.ellerman.id.au/kisskb/head/10047/ (all 262 configs) > > > > > 9 error regressions: > > > + /home/kisskb/slave/src/fs/xfs/xfs_ondisk.h: error: call to > > > '__compiletime_assert_79' declared with attribute error: XFS: > > > sizeof(xfs_attr_shortform_t) is wrong, expected 8: => 79:2 > > > > cris-allyesconfig, cris-allmodconfig > > Yup, cris is the only platform that throws this error on this > structure. It's an on-disk structure and relying on the gcc > optimiser to do the same thing from release to release has become > such a crap-shoot these days. Hence as a stop-gap measure we added > build time checking of what they compiler is doing with those > structures, and to refuse to build XFS if the compiler/platform is > doing something obviously different. > > Modernising the on-disk structure definitions is on the list of > things to do, but it's nowhere near the top of my list at the > moment... I have a test patch that (for now) changes the ondisk format checks for the variable-length structures to look at the offsets of the non-variable-length fields. Can you give it a try? (No idea if it fixes fixes cris, but it passes the six arches that I can actually test on (x86/power/arm)). The downside is that it does nothing about troubling implication that there could be computers writing out a disk format that's incompatible with x86 XFSes...) --D ----------- From: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Subject: [PATCH] xfs: check offsets of variable length structures Some of the directory/attr structures contain variable-length objects, so the enclosing structure doesn't have a meaningful fixed size at compile time. We can check the offsets of the members before the variable-length member, so do those. Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> --- fs/xfs/xfs_ondisk.h | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h index 960648b..3742216 100644 --- a/fs/xfs/xfs_ondisk.h +++ b/fs/xfs/xfs_ondisk.h @@ -22,6 +22,11 @@ BUILD_BUG_ON_MSG(sizeof(structname) != (size), "XFS: sizeof(" \ #structname ") is wrong, expected " #size) +#define XFS_CHECK_OFFSET(structname, member, off) \ + BUILD_BUG_ON_MSG(offsetof(structname, member) != (off), \ + "XFS: offsetof(" #structname ", " #member ") is wrong, " \ + "expected " #off) + static inline void __init xfs_check_ondisk_structs(void) { @@ -81,15 +86,28 @@ xfs_check_ondisk_structs(void) XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_name_remote_t, 12); */ + XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, valuelen, 0); + XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, namelen, 2); + XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, nameval, 3); + XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valueblk, 0); + XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valuelen, 4); + XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, namelen, 8); + XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, name, 9); XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t, 40); - XFS_CHECK_STRUCT_SIZE(xfs_attr_shortform_t, 8); + XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.totsize, 0); + XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.count, 2); + XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].namelen, 4); + XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].valuelen, 5); + XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].flags, 6); + XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].nameval, 7); XFS_CHECK_STRUCT_SIZE(xfs_da_blkinfo_t, 12); XFS_CHECK_STRUCT_SIZE(xfs_da_intnode_t, 16); XFS_CHECK_STRUCT_SIZE(xfs_da_node_entry_t, 8); XFS_CHECK_STRUCT_SIZE(xfs_da_node_hdr_t, 16); XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_free_t, 4); XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_hdr_t, 16); - XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_unused_t, 6); + XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, freetag, 0); + XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, length, 2); XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_hdr_t, 16); XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_t, 16); XFS_CHECK_STRUCT_SIZE(xfs_dir2_ino4_t, 4); @@ -100,6 +118,9 @@ xfs_check_ondisk_structs(void) XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_t, 16); XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_tail_t, 4); XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_entry_t, 3); + XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, namelen, 0); + XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, offset, 1); + XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, name, 3); XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_hdr_t, 10); XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_off_t, 2); _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
