In no-modify mode (-n), verify_set_agf doesn't fix up bad freelist blocks that it finds. When we get to scan_freelist, this can wreak havoc if, for example, first > last and the loop never exits; we index agfl->agfl_bno[i] off into the weeds. To fix this, re-check the values in no-modify mode, and if they're off, warn about it and skip the scan. In addition, add a check to verify_set_agf() to ensure that first <= last. Reported-by: Ole Tange <tange@xxxxxxxxxx> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> --- diff --git a/repair/agheader.c b/repair/agheader.c index 769022d..68789fe 100644 --- a/repair/agheader.c +++ b/repair/agheader.c @@ -86,6 +86,14 @@ verify_set_agf(xfs_mount_t *mp, xfs_agf_t *agf, xfs_agnumber_t i) * check first/last AGF fields. if need be, lose the free * space in the AGFL, we'll reclaim it later. */ + if (be32_to_cpu(agf->agf_flfirst) > be32_to_cpu(agf->agf_fllast)) { + do_warn(_("flfirst %d in agf %d > fllast %d\n"), + be32_to_cpu(agf->agf_flfirst), + i, be32_to_cpu(agf->agf_fllast)); + if (!no_modify) + agf->agf_fllast = agf->agf_flfirst = cpu_to_be32(0); + } + if (be32_to_cpu(agf->agf_flfirst) >= XFS_AGFL_SIZE(mp)) { do_warn(_("flfirst %d in agf %d too large (max = %zu)\n"), be32_to_cpu(agf->agf_flfirst), diff --git a/repair/scan.c b/repair/scan.c index 5345094..0f83fb4 100644 --- a/repair/scan.c +++ b/repair/scan.c @@ -1067,6 +1067,17 @@ scan_freelist( } agfl = XFS_BUF_TO_AGFL(agflbuf); i = be32_to_cpu(agf->agf_flfirst); + if (no_modify) { + /* agf values not sanitized, so double check */ + if (i >= XFS_AGFL_SIZE(mp) || + be32_to_cpu(agf->agf_fllast) >= XFS_AGFL_SIZE(mp) || + i > be32_to_cpu(agf->agf_fllast)) + do_warn(_("agf %d freelist blocks bad, skipping scan\n"), + i); + return; + } else /* should have been fixed in verify_set_agf() */ + ASSERT(0); + count = 0; for (;;) { bno = be32_to_cpu(agfl->agfl_bno[i]); _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs