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xfs: check the uniqueness of the AGFL entries 

Make sure we don't list a block twice in the agfl by copying the
contents of the AGFL to an array, sorting it, and looking for
duplicates.  We can easily check that the number of agfl entries we see
actually matches the flcount, so do that too.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Darrick J. Wong 2017-11-02 15:58:36 -07:00
parent 65a7935ddc
commit d44b47fdd1
1 changed files with 61 additions and 2 deletions
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63
fs/xfs/scrub/agheader.c
View File

@ -476,6 +476,12 @@ out:
/* AGFL */
struct xfs_scrub_agfl_info {
unsigned int sz_entries;
unsigned int nr_entries;
xfs_agblock_t *entries;
};
/* Scrub an AGFL block. */
STATIC int
xfs_scrub_agfl_block(
@ -484,20 +490,39 @@ 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->nr_entries < sai->sz_entries)
sai->entries[sai->nr_entries++] = agbno;
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 +533,42 @@ 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.sz_entries = agflcount;
sai.entries = kmem_zalloc(sizeof(xfs_agblock_t) * agflcount, 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;
if (agflcount != sai.nr_entries) {
xfs_scrub_block_set_corrupt(sc, sc->sa.agf_bp);
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;
}