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xfs: check reference counts of gaps between rt refcount records

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If there's a gap between records in the rt refcount btree, we ought to
cross-reference the gap with the rtrmap records to make sure that there
aren't any overlapping records for a region that doesn't have any shared
ownership.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2024-11-20 16:21:08 -08:00
parent 2d9a3e9805
commit 30f47950dc
1 changed files with 80 additions and 1 deletions
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81
fs/xfs/scrub/rtrefcount.c
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@ -17,6 +17,7 @@
#include "xfs_rtgroup.h"
#include "xfs_metafile.h"
#include "xfs_rtrefcount_btree.h"
#include "xfs_rtalloc.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/btree.h"
@ -348,8 +349,14 @@ struct xchk_rtrefcbt_records {
/* Previous refcount record. */
struct xfs_refcount_irec prev_rec;
/* The next rtgroup block where we aren't expecting shared extents. */
xfs_rgblock_t next_unshared_rgbno;
/* Number of CoW blocks we expect. */
xfs_extlen_t cow_blocks;
/* Was the last record a shared or CoW staging extent? */
enum xfs_refc_domain prev_domain;
};
static inline bool
@ -390,6 +397,53 @@ xchk_rtrefcountbt_check_mergeable(
memcpy(&rrc->prev_rec, irec, sizeof(struct xfs_refcount_irec));
}
STATIC int
xchk_rtrefcountbt_rmap_check_gap(
struct xfs_btree_cur *cur,
const struct xfs_rmap_irec *rec,
void *priv)
{
xfs_rgblock_t *next_bno = priv;
if (*next_bno != NULLRGBLOCK && rec->rm_startblock < *next_bno)
return -ECANCELED;
*next_bno = rec->rm_startblock + rec->rm_blockcount;
return 0;
}
/*
* Make sure that a gap in the reference count records does not correspond to
* overlapping records (i.e. shared extents) in the reverse mappings.
*/
static inline void
xchk_rtrefcountbt_xref_gaps(
struct xfs_scrub *sc,
struct xchk_rtrefcbt_records *rrc,
xfs_rtblock_t bno)
{
struct xfs_rmap_irec low;
struct xfs_rmap_irec high;
xfs_rgblock_t next_bno = NULLRGBLOCK;
int error;
if (bno <= rrc->next_unshared_rgbno || !sc->sr.rmap_cur ||
xchk_skip_xref(sc->sm))
return;
memset(&low, 0, sizeof(low));
low.rm_startblock = rrc->next_unshared_rgbno;
memset(&high, 0xFF, sizeof(high));
high.rm_startblock = bno - 1;
error = xfs_rmap_query_range(sc->sr.rmap_cur, &low, &high,
xchk_rtrefcountbt_rmap_check_gap, &next_bno);
if (error == -ECANCELED)
xchk_btree_xref_set_corrupt(sc, sc->sr.rmap_cur, 0);
else
xchk_should_check_xref(sc, &error, &sc->sr.rmap_cur);
}
/* Scrub a rtrefcountbt record. */
STATIC int
xchk_rtrefcountbt_rec(
@ -419,9 +473,26 @@ xchk_rtrefcountbt_rec(
if (irec.rc_domain == XFS_REFC_DOMAIN_COW)
rrc->cow_blocks += irec.rc_blockcount;
/* Shared records always come before CoW records. */
if (irec.rc_domain == XFS_REFC_DOMAIN_SHARED &&
rrc->prev_domain == XFS_REFC_DOMAIN_COW)
xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
rrc->prev_domain = irec.rc_domain;
xchk_rtrefcountbt_check_mergeable(bs, rrc, &irec);
xchk_rtrefcountbt_xref(bs->sc, &irec);
/*
* If this is a record for a shared extent, check that all blocks
* between the previous record and this one have at most one reverse
* mapping.
*/
if (irec.rc_domain == XFS_REFC_DOMAIN_SHARED) {
xchk_rtrefcountbt_xref_gaps(bs->sc, rrc, irec.rc_startblock);
rrc->next_unshared_rgbno = irec.rc_startblock +
irec.rc_blockcount;
}
return 0;
}
@ -466,7 +537,9 @@ xchk_rtrefcountbt(
{
struct xfs_owner_info btree_oinfo;
struct xchk_rtrefcbt_records rrc = {
.cow_blocks = 0,
.cow_blocks = 0,
.next_unshared_rgbno = 0,
.prev_domain = XFS_REFC_DOMAIN_SHARED,
};
int error;
@ -481,6 +554,12 @@ xchk_rtrefcountbt(
if (error || (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
return error;
/*
* Check that all blocks between the last refcount > 1 record and the
* end of the rt volume have at most one reverse mapping.
*/
xchk_rtrefcountbt_xref_gaps(sc, &rrc, sc->mp->m_sb.sb_rblocks);
xchk_refcount_xref_rmap(sc, &btree_oinfo, rrc.cow_blocks);
return 0;