On Tue, Jan 08, 2019 at 12:32:47PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> In xchk_iallocbt_rec, check the alignment of ir_startino by converting
> the inode cluster block alignment into units of inodes instead of the
> other way around (converting ir_startino to blocks). This prevents us
> from tripping over off-by-one errors in ir_startino which are obscured
> by the inode -> block conversion.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/xfs/scrub/ialloc.c | 56 ++++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 50 insertions(+), 6 deletions(-)
>
>
> diff --git a/fs/xfs/scrub/ialloc.c b/fs/xfs/scrub/ialloc.c
> index fd431682db0b..1c6fef9b3799 100644
> --- a/fs/xfs/scrub/ialloc.c
> +++ b/fs/xfs/scrub/ialloc.c
> @@ -265,6 +265,53 @@ xchk_iallocbt_check_freemask(
> return error;
> }
>
> +/*
> + * Make sure this inode btree record is aligned properly. Because a fs block
> + * contains multiple inodes, we check that the inobt record is aligned to the
> + * correct inode, not just the correct block on disk. This results in a finer
> + * grained corruption check.
> + */
> +STATIC void
> +xchk_iallocbt_rec_alignment(
> + struct xchk_btree *bs,
> + struct xfs_inobt_rec_incore *irec)
> +{
> + struct xfs_mount *mp = bs->sc->mp;
> +
> + /*
> + * finobt records have different positioning requirements than inobt
> + * records: each finobt record must have a corresponding inobt record.
> + * That is checked in the xref function, so for now we only catch the
> + * obvious case where the record isn't at all aligned properly.
> + *
> + * Note that if a fs block contains more than a single chunk of inodes,
> + * we will have finobt records only for those chunks containing free
> + * inodes, and therefore expect chunk alignment of finobt records.
> + * Otherwise, we expect that the finobt record is aligned to the
> + * cluster alignment as told by the superblock.
> + */
> + if (bs->cur->bc_btnum == XFS_BTNUM_FINO) {
> + unsigned int imask;
> +
> + imask = min_t(unsigned int, XFS_INODES_PER_CHUNK,
> + mp->m_cluster_align_inodes) - 1;
> + if (irec->ir_startino & imask)
> + xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
> + return;
> + }
> +
Don't we also need this large FSB alignment fixup for inobt records, or
am I still confused? :/ I.e., if ->m_cluster_align_inodes is 128 and
irec is the second inobt record in a block..
Brian
> + /* inobt records must be aligned to cluster and inoalignmnt size. */
> + if (irec->ir_startino & (mp->m_cluster_align_inodes - 1)) {
> + xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
> + return;
> + }
> +
> + if (irec->ir_startino & (mp->m_inodes_per_cluster - 1)) {
> + xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
> + return;
> + }
> +}
> +
> /* Scrub an inobt/finobt record. */
> STATIC int
> xchk_iallocbt_rec(
> @@ -277,7 +324,6 @@ xchk_iallocbt_rec(
> uint64_t holes;
> xfs_agnumber_t agno = bs->cur->bc_private.a.agno;
> xfs_agino_t agino;
> - xfs_agblock_t agbno;
> xfs_extlen_t len;
> int holecount;
> int i;
> @@ -304,11 +350,9 @@ xchk_iallocbt_rec(
> goto out;
> }
>
> - /* Make sure this record is aligned to cluster and inoalignmnt size. */
> - agbno = XFS_AGINO_TO_AGBNO(mp, irec.ir_startino);
> - if ((agbno & (mp->m_cluster_align - 1)) ||
> - (agbno & (mp->m_blocks_per_cluster - 1)))
> - xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
> + xchk_iallocbt_rec_alignment(bs, &irec);
> + if (bs->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
> + goto out;
>
> iabt->inodes += irec.ir_count;
>
>
