On Wed, Nov 08, 2017 at 09:02:35PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Make sure we don't list a block twice in the agfl.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> v2: various review cleanups
> ---
> fs/xfs/scrub/agheader.c | 56 +++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 54 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/scrub/agheader.c b/fs/xfs/scrub/agheader.c
> index 5495aa5..489f985 100644
> --- a/fs/xfs/scrub/agheader.c
> +++ b/fs/xfs/scrub/agheader.c
> @@ -476,6 +476,11 @@ xfs_scrub_agf(
>
> /* AGFL */
>
> +struct xfs_scrub_agfl_info {
> + unsigned int nr_entries;
> + xfs_agblock_t *entries;
> +};
> +
> /* Scrub an AGFL block. */
> STATIC int
> xfs_scrub_agfl_block(
> @@ -484,20 +489,38 @@ xfs_scrub_agfl_block(
> void *priv)
> {
> struct xfs_mount *mp = sc->mp;
> + struct xfs_scrub_agfl_info *sai = priv;
> xfs_agnumber_t agno = sc->sa.agno;
>
> - if (!xfs_verify_agbno(mp, agno, agbno))
> + if (xfs_verify_agbno(mp, agno, agbno))
> + sai->entries[sai->nr_entries++] = agbno;
self-NAK on this second version, because we need to ensure that we don't
overflow or underflow the entries array -- in other words, that flfirst
and fllast exactly match flcount.
--D
> + else
> xfs_scrub_block_set_corrupt(sc, sc->sa.agfl_bp);
>
> return 0;
> }
>
> +static int
> +xfs_scrub_agblock_cmp(
> + const void *pa,
> + const void *pb)
> +{
> + const xfs_agblock_t *a = pa;
> + const xfs_agblock_t *b = pb;
> +
> + return (int)*a - (int)*b;
> +}
> +
> /* Scrub the AGFL. */
> int
> xfs_scrub_agfl(
> struct xfs_scrub_context *sc)
> {
> + struct xfs_scrub_agfl_info sai = { 0 };
> + struct xfs_agf *agf;
> xfs_agnumber_t agno;
> + unsigned int agflcount;
> + unsigned int i;
> int error;
>
> agno = sc->sa.agno = sc->sm->sm_agno;
> @@ -508,8 +531,37 @@ xfs_scrub_agfl(
> if (!sc->sa.agf_bp)
> return -EFSCORRUPTED;
>
> + /* Allocate buffer to ensure uniqueness of AGFL entries. */
> + agf = XFS_BUF_TO_AGF(sc->sa.agf_bp);
> + agflcount = be32_to_cpu(agf->agf_flcount);
> + if (agflcount > XFS_AGFL_SIZE(sc->mp)) {
> + xfs_scrub_block_set_corrupt(sc, sc->sa.agf_bp);
> + goto out;
> + }
> + sai.entries = kmem_zalloc(sizeof(xfs_agblock_t) * agflcount,
> + KM_SLEEP | KM_NOFS);
> + if (!sai.entries) {
> + error = -ENOMEM;
> + goto out;
> + }
> +
> /* Check the blocks in the AGFL. */
> - return xfs_scrub_walk_agfl(sc, xfs_scrub_agfl_block, NULL);
> + error = xfs_scrub_walk_agfl(sc, xfs_scrub_agfl_block, &sai);
> + if (error)
> + goto out_free;
> +
> + /* Sort entries, check for duplicates. */
> + sort(sai.entries, sai.nr_entries, sizeof(sai.entries[0]),
> + xfs_scrub_agblock_cmp, NULL);
> + for (i = 1; i < sai.nr_entries; i++) {
> + if (sai.entries[i] == sai.entries[i - 1]) {
> + xfs_scrub_block_set_corrupt(sc, sc->sa.agf_bp);
> + break;
> + }
> + }
> +
> +out_free:
> + kmem_free(sai.entries);
> out:
> return error;
> }
> --
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