linux/fs/xfs/scrub/alloc.c
Darrick J. Wong 7ac14fa2bd xfs: ensure that all metadata and data blocks are not cow staging extents
Make sure that all filesystem metadata blocks and file data blocks are
not also marked as CoW staging extents.  The extra checking added here
was inspired by an actual VM host filesystem corruption incident due to
bugs in the CoW handling of 4.x kernels.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:12 -07:00

160 lines
3.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017-2023 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_btree.h"
#include "xfs_alloc.h"
#include "xfs_rmap.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/btree.h"
#include "xfs_ag.h"
/*
* Set us up to scrub free space btrees.
*/
int
xchk_setup_ag_allocbt(
struct xfs_scrub *sc)
{
if (xchk_need_intent_drain(sc))
xchk_fsgates_enable(sc, XCHK_FSGATES_DRAIN);
return xchk_setup_ag_btree(sc, false);
}
/* Free space btree scrubber. */
/*
* Ensure there's a corresponding cntbt/bnobt record matching this
* bnobt/cntbt record, respectively.
*/
STATIC void
xchk_allocbt_xref_other(
struct xfs_scrub *sc,
xfs_agblock_t agbno,
xfs_extlen_t len)
{
struct xfs_btree_cur **pcur;
xfs_agblock_t fbno;
xfs_extlen_t flen;
int has_otherrec;
int error;
if (sc->sm->sm_type == XFS_SCRUB_TYPE_BNOBT)
pcur = &sc->sa.cnt_cur;
else
pcur = &sc->sa.bno_cur;
if (!*pcur || xchk_skip_xref(sc->sm))
return;
error = xfs_alloc_lookup_le(*pcur, agbno, len, &has_otherrec);
if (!xchk_should_check_xref(sc, &error, pcur))
return;
if (!has_otherrec) {
xchk_btree_xref_set_corrupt(sc, *pcur, 0);
return;
}
error = xfs_alloc_get_rec(*pcur, &fbno, &flen, &has_otherrec);
if (!xchk_should_check_xref(sc, &error, pcur))
return;
if (!has_otherrec) {
xchk_btree_xref_set_corrupt(sc, *pcur, 0);
return;
}
if (fbno != agbno || flen != len)
xchk_btree_xref_set_corrupt(sc, *pcur, 0);
}
/* Cross-reference with the other btrees. */
STATIC void
xchk_allocbt_xref(
struct xfs_scrub *sc,
const struct xfs_alloc_rec_incore *irec)
{
xfs_agblock_t agbno = irec->ar_startblock;
xfs_extlen_t len = irec->ar_blockcount;
if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
return;
xchk_allocbt_xref_other(sc, agbno, len);
xchk_xref_is_not_inode_chunk(sc, agbno, len);
xchk_xref_has_no_owner(sc, agbno, len);
xchk_xref_is_not_shared(sc, agbno, len);
xchk_xref_is_not_cow_staging(sc, agbno, len);
}
/* Scrub a bnobt/cntbt record. */
STATIC int
xchk_allocbt_rec(
struct xchk_btree *bs,
const union xfs_btree_rec *rec)
{
struct xfs_alloc_rec_incore irec;
xfs_alloc_btrec_to_irec(rec, &irec);
if (xfs_alloc_check_irec(bs->cur, &irec) != NULL) {
xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
return 0;
}
xchk_allocbt_xref(bs->sc, &irec);
return 0;
}
/* Scrub the freespace btrees for some AG. */
STATIC int
xchk_allocbt(
struct xfs_scrub *sc,
xfs_btnum_t which)
{
struct xfs_btree_cur *cur;
cur = which == XFS_BTNUM_BNO ? sc->sa.bno_cur : sc->sa.cnt_cur;
return xchk_btree(sc, cur, xchk_allocbt_rec, &XFS_RMAP_OINFO_AG, NULL);
}
int
xchk_bnobt(
struct xfs_scrub *sc)
{
return xchk_allocbt(sc, XFS_BTNUM_BNO);
}
int
xchk_cntbt(
struct xfs_scrub *sc)
{
return xchk_allocbt(sc, XFS_BTNUM_CNT);
}
/* xref check that the extent is not free */
void
xchk_xref_is_used_space(
struct xfs_scrub *sc,
xfs_agblock_t agbno,
xfs_extlen_t len)
{
enum xbtree_recpacking outcome;
int error;
if (!sc->sa.bno_cur || xchk_skip_xref(sc->sm))
return;
error = xfs_alloc_has_records(sc->sa.bno_cur, agbno, len, &outcome);
if (!xchk_should_check_xref(sc, &error, &sc->sa.bno_cur))
return;
if (outcome != XBTREE_RECPACKING_EMPTY)
xchk_btree_xref_set_corrupt(sc, sc->sa.bno_cur, 0);
}