From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- fs/xfs/scrub/refcount.c | 620 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 620 insertions(+) create mode 100644 fs/xfs/scrub/refcount.c (limited to 'fs/xfs/scrub/refcount.c') diff --git a/fs/xfs/scrub/refcount.c b/fs/xfs/scrub/refcount.c new file mode 100644 index 0000000000..304ea1e1bf --- /dev/null +++ b/fs/xfs/scrub/refcount.c @@ -0,0 +1,620 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2017-2023 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#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_ag.h" +#include "xfs_btree.h" +#include "xfs_rmap.h" +#include "xfs_refcount.h" +#include "scrub/scrub.h" +#include "scrub/common.h" +#include "scrub/btree.h" +#include "scrub/trace.h" + +/* + * Set us up to scrub reference count btrees. + */ +int +xchk_setup_ag_refcountbt( + struct xfs_scrub *sc) +{ + if (xchk_need_intent_drain(sc)) + xchk_fsgates_enable(sc, XCHK_FSGATES_DRAIN); + return xchk_setup_ag_btree(sc, false); +} + +/* Reference count btree scrubber. */ + +/* + * Confirming Reference Counts via Reverse Mappings + * + * We want to count the reverse mappings overlapping a refcount record + * (bno, len, refcount), allowing for the possibility that some of the + * overlap may come from smaller adjoining reverse mappings, while some + * comes from single extents which overlap the range entirely. The + * outer loop is as follows: + * + * 1. For all reverse mappings overlapping the refcount extent, + * a. If a given rmap completely overlaps, mark it as seen. + * b. Otherwise, record the fragment (in agbno order) for later + * processing. + * + * Once we've seen all the rmaps, we know that for all blocks in the + * refcount record we want to find $refcount owners and we've already + * visited $seen extents that overlap all the blocks. Therefore, we + * need to find ($refcount - $seen) owners for every block in the + * extent; call that quantity $target_nr. Proceed as follows: + * + * 2. Pull the first $target_nr fragments from the list; all of them + * should start at or before the start of the extent. + * Call this subset of fragments the working set. + * 3. Until there are no more unprocessed fragments, + * a. Find the shortest fragments in the set and remove them. + * b. Note the block number of the end of these fragments. + * c. Pull the same number of fragments from the list. All of these + * fragments should start at the block number recorded in the + * previous step. + * d. Put those fragments in the set. + * 4. Check that there are $target_nr fragments remaining in the list, + * and that they all end at or beyond the end of the refcount extent. + * + * If the refcount is correct, all the check conditions in the algorithm + * should always hold true. If not, the refcount is incorrect. + */ +struct xchk_refcnt_frag { + struct list_head list; + struct xfs_rmap_irec rm; +}; + +struct xchk_refcnt_check { + struct xfs_scrub *sc; + struct list_head fragments; + + /* refcount extent we're examining */ + xfs_agblock_t bno; + xfs_extlen_t len; + xfs_nlink_t refcount; + + /* number of owners seen */ + xfs_nlink_t seen; +}; + +/* + * Decide if the given rmap is large enough that we can redeem it + * towards refcount verification now, or if it's a fragment, in + * which case we'll hang onto it in the hopes that we'll later + * discover that we've collected exactly the correct number of + * fragments as the refcountbt says we should have. + */ +STATIC int +xchk_refcountbt_rmap_check( + struct xfs_btree_cur *cur, + const struct xfs_rmap_irec *rec, + void *priv) +{ + struct xchk_refcnt_check *refchk = priv; + struct xchk_refcnt_frag *frag; + xfs_agblock_t rm_last; + xfs_agblock_t rc_last; + int error = 0; + + if (xchk_should_terminate(refchk->sc, &error)) + return error; + + rm_last = rec->rm_startblock + rec->rm_blockcount - 1; + rc_last = refchk->bno + refchk->len - 1; + + /* Confirm that a single-owner refc extent is a CoW stage. */ + if (refchk->refcount == 1 && rec->rm_owner != XFS_RMAP_OWN_COW) { + xchk_btree_xref_set_corrupt(refchk->sc, cur, 0); + return 0; + } + + if (rec->rm_startblock <= refchk->bno && rm_last >= rc_last) { + /* + * The rmap overlaps the refcount record, so we can confirm + * one refcount owner seen. + */ + refchk->seen++; + } else { + /* + * This rmap covers only part of the refcount record, so + * save the fragment for later processing. If the rmapbt + * is healthy each rmap_irec we see will be in agbno order + * so we don't need insertion sort here. + */ + frag = kmalloc(sizeof(struct xchk_refcnt_frag), + XCHK_GFP_FLAGS); + if (!frag) + return -ENOMEM; + memcpy(&frag->rm, rec, sizeof(frag->rm)); + list_add_tail(&frag->list, &refchk->fragments); + } + + return 0; +} + +/* + * Given a bunch of rmap fragments, iterate through them, keeping + * a running tally of the refcount. If this ever deviates from + * what we expect (which is the refcountbt's refcount minus the + * number of extents that totally covered the refcountbt extent), + * we have a refcountbt error. + */ +STATIC void +xchk_refcountbt_process_rmap_fragments( + struct xchk_refcnt_check *refchk) +{ + struct list_head worklist; + struct xchk_refcnt_frag *frag; + struct xchk_refcnt_frag *n; + xfs_agblock_t bno; + xfs_agblock_t rbno; + xfs_agblock_t next_rbno; + xfs_nlink_t nr; + xfs_nlink_t target_nr; + + target_nr = refchk->refcount - refchk->seen; + if (target_nr == 0) + return; + + /* + * There are (refchk->rc.rc_refcount - refchk->nr refcount) + * references we haven't found yet. Pull that many off the + * fragment list and figure out where the smallest rmap ends + * (and therefore the next rmap should start). All the rmaps + * we pull off should start at or before the beginning of the + * refcount record's range. + */ + INIT_LIST_HEAD(&worklist); + rbno = NULLAGBLOCK; + + /* Make sure the fragments actually /are/ in agbno order. */ + bno = 0; + list_for_each_entry(frag, &refchk->fragments, list) { + if (frag->rm.rm_startblock < bno) + goto done; + bno = frag->rm.rm_startblock; + } + + /* + * Find all the rmaps that start at or before the refc extent, + * and put them on the worklist. + */ + nr = 0; + list_for_each_entry_safe(frag, n, &refchk->fragments, list) { + if (frag->rm.rm_startblock > refchk->bno || nr > target_nr) + break; + bno = frag->rm.rm_startblock + frag->rm.rm_blockcount; + if (bno < rbno) + rbno = bno; + list_move_tail(&frag->list, &worklist); + nr++; + } + + /* + * We should have found exactly $target_nr rmap fragments starting + * at or before the refcount extent. + */ + if (nr != target_nr) + goto done; + + while (!list_empty(&refchk->fragments)) { + /* Discard any fragments ending at rbno from the worklist. */ + nr = 0; + next_rbno = NULLAGBLOCK; + list_for_each_entry_safe(frag, n, &worklist, list) { + bno = frag->rm.rm_startblock + frag->rm.rm_blockcount; + if (bno != rbno) { + if (bno < next_rbno) + next_rbno = bno; + continue; + } + list_del(&frag->list); + kfree(frag); + nr++; + } + + /* Try to add nr rmaps starting at rbno to the worklist. */ + list_for_each_entry_safe(frag, n, &refchk->fragments, list) { + bno = frag->rm.rm_startblock + frag->rm.rm_blockcount; + if (frag->rm.rm_startblock != rbno) + goto done; + list_move_tail(&frag->list, &worklist); + if (next_rbno > bno) + next_rbno = bno; + nr--; + if (nr == 0) + break; + } + + /* + * If we get here and nr > 0, this means that we added fewer + * items to the worklist than we discarded because the fragment + * list ran out of items. Therefore, we cannot maintain the + * required refcount. Something is wrong, so we're done. + */ + if (nr) + goto done; + + rbno = next_rbno; + } + + /* + * Make sure the last extent we processed ends at or beyond + * the end of the refcount extent. + */ + if (rbno < refchk->bno + refchk->len) + goto done; + + /* Actually record us having seen the remaining refcount. */ + refchk->seen = refchk->refcount; +done: + /* Delete fragments and work list. */ + list_for_each_entry_safe(frag, n, &worklist, list) { + list_del(&frag->list); + kfree(frag); + } + list_for_each_entry_safe(frag, n, &refchk->fragments, list) { + list_del(&frag->list); + kfree(frag); + } +} + +/* Use the rmap entries covering this extent to verify the refcount. */ +STATIC void +xchk_refcountbt_xref_rmap( + struct xfs_scrub *sc, + const struct xfs_refcount_irec *irec) +{ + struct xchk_refcnt_check refchk = { + .sc = sc, + .bno = irec->rc_startblock, + .len = irec->rc_blockcount, + .refcount = irec->rc_refcount, + .seen = 0, + }; + struct xfs_rmap_irec low; + struct xfs_rmap_irec high; + struct xchk_refcnt_frag *frag; + struct xchk_refcnt_frag *n; + int error; + + if (!sc->sa.rmap_cur || xchk_skip_xref(sc->sm)) + return; + + /* Cross-reference with the rmapbt to confirm the refcount. */ + memset(&low, 0, sizeof(low)); + low.rm_startblock = irec->rc_startblock; + memset(&high, 0xFF, sizeof(high)); + high.rm_startblock = irec->rc_startblock + irec->rc_blockcount - 1; + + INIT_LIST_HEAD(&refchk.fragments); + error = xfs_rmap_query_range(sc->sa.rmap_cur, &low, &high, + &xchk_refcountbt_rmap_check, &refchk); + if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur)) + goto out_free; + + xchk_refcountbt_process_rmap_fragments(&refchk); + if (irec->rc_refcount != refchk.seen) { + trace_xchk_refcount_incorrect(sc->sa.pag, irec, refchk.seen); + xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0); + } + +out_free: + list_for_each_entry_safe(frag, n, &refchk.fragments, list) { + list_del(&frag->list); + kfree(frag); + } +} + +/* Cross-reference with the other btrees. */ +STATIC void +xchk_refcountbt_xref( + struct xfs_scrub *sc, + const struct xfs_refcount_irec *irec) +{ + if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) + return; + + xchk_xref_is_used_space(sc, irec->rc_startblock, irec->rc_blockcount); + xchk_xref_is_not_inode_chunk(sc, irec->rc_startblock, + irec->rc_blockcount); + xchk_refcountbt_xref_rmap(sc, irec); +} + +struct xchk_refcbt_records { + /* Previous refcount record. */ + struct xfs_refcount_irec prev_rec; + + /* The next AG block where we aren't expecting shared extents. */ + xfs_agblock_t next_unshared_agbno; + + /* Number of CoW blocks we expect. */ + xfs_agblock_t cow_blocks; + + /* Was the last record a shared or CoW staging extent? */ + enum xfs_refc_domain prev_domain; +}; + +STATIC int +xchk_refcountbt_rmap_check_gap( + struct xfs_btree_cur *cur, + const struct xfs_rmap_irec *rec, + void *priv) +{ + xfs_agblock_t *next_bno = priv; + + if (*next_bno != NULLAGBLOCK && 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_refcountbt_xref_gaps( + struct xfs_scrub *sc, + struct xchk_refcbt_records *rrc, + xfs_agblock_t bno) +{ + struct xfs_rmap_irec low; + struct xfs_rmap_irec high; + xfs_agblock_t next_bno = NULLAGBLOCK; + int error; + + if (bno <= rrc->next_unshared_agbno || !sc->sa.rmap_cur || + xchk_skip_xref(sc->sm)) + return; + + memset(&low, 0, sizeof(low)); + low.rm_startblock = rrc->next_unshared_agbno; + memset(&high, 0xFF, sizeof(high)); + high.rm_startblock = bno - 1; + + error = xfs_rmap_query_range(sc->sa.rmap_cur, &low, &high, + xchk_refcountbt_rmap_check_gap, &next_bno); + if (error == -ECANCELED) + xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0); + else + xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur); +} + +static inline bool +xchk_refcount_mergeable( + struct xchk_refcbt_records *rrc, + const struct xfs_refcount_irec *r2) +{ + const struct xfs_refcount_irec *r1 = &rrc->prev_rec; + + /* Ignore if prev_rec is not yet initialized. */ + if (r1->rc_blockcount > 0) + return false; + + if (r1->rc_domain != r2->rc_domain) + return false; + if (r1->rc_startblock + r1->rc_blockcount != r2->rc_startblock) + return false; + if (r1->rc_refcount != r2->rc_refcount) + return false; + if ((unsigned long long)r1->rc_blockcount + r2->rc_blockcount > + MAXREFCEXTLEN) + return false; + + return true; +} + +/* Flag failures for records that could be merged. */ +STATIC void +xchk_refcountbt_check_mergeable( + struct xchk_btree *bs, + struct xchk_refcbt_records *rrc, + const struct xfs_refcount_irec *irec) +{ + if (bs->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) + return; + + if (xchk_refcount_mergeable(rrc, irec)) + xchk_btree_set_corrupt(bs->sc, bs->cur, 0); + + memcpy(&rrc->prev_rec, irec, sizeof(struct xfs_refcount_irec)); +} + +/* Scrub a refcountbt record. */ +STATIC int +xchk_refcountbt_rec( + struct xchk_btree *bs, + const union xfs_btree_rec *rec) +{ + struct xfs_refcount_irec irec; + struct xchk_refcbt_records *rrc = bs->private; + + xfs_refcount_btrec_to_irec(rec, &irec); + if (xfs_refcount_check_irec(bs->cur, &irec) != NULL) { + xchk_btree_set_corrupt(bs->sc, bs->cur, 0); + return 0; + } + + 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_refcountbt_check_mergeable(bs, rrc, &irec); + xchk_refcountbt_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_refcountbt_xref_gaps(bs->sc, rrc, irec.rc_startblock); + rrc->next_unshared_agbno = irec.rc_startblock + + irec.rc_blockcount; + } + + return 0; +} + +/* Make sure we have as many refc blocks as the rmap says. */ +STATIC void +xchk_refcount_xref_rmap( + struct xfs_scrub *sc, + xfs_filblks_t cow_blocks) +{ + xfs_extlen_t refcbt_blocks = 0; + xfs_filblks_t blocks; + int error; + + if (!sc->sa.rmap_cur || xchk_skip_xref(sc->sm)) + return; + + /* Check that we saw as many refcbt blocks as the rmap knows about. */ + error = xfs_btree_count_blocks(sc->sa.refc_cur, &refcbt_blocks); + if (!xchk_btree_process_error(sc, sc->sa.refc_cur, 0, &error)) + return; + error = xchk_count_rmap_ownedby_ag(sc, sc->sa.rmap_cur, + &XFS_RMAP_OINFO_REFC, &blocks); + if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur)) + return; + if (blocks != refcbt_blocks) + xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0); + + /* Check that we saw as many cow blocks as the rmap knows about. */ + error = xchk_count_rmap_ownedby_ag(sc, sc->sa.rmap_cur, + &XFS_RMAP_OINFO_COW, &blocks); + if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur)) + return; + if (blocks != cow_blocks) + xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0); +} + +/* Scrub the refcount btree for some AG. */ +int +xchk_refcountbt( + struct xfs_scrub *sc) +{ + struct xchk_refcbt_records rrc = { + .cow_blocks = 0, + .next_unshared_agbno = 0, + .prev_domain = XFS_REFC_DOMAIN_SHARED, + }; + int error; + + error = xchk_btree(sc, sc->sa.refc_cur, xchk_refcountbt_rec, + &XFS_RMAP_OINFO_REFC, &rrc); + if (error) + return error; + + /* + * Check that all blocks between the last refcount > 1 record and the + * end of the AG have at most one reverse mapping. + */ + xchk_refcountbt_xref_gaps(sc, &rrc, sc->mp->m_sb.sb_agblocks); + + xchk_refcount_xref_rmap(sc, rrc.cow_blocks); + + return 0; +} + +/* xref check that a cow staging extent is marked in the refcountbt. */ +void +xchk_xref_is_cow_staging( + struct xfs_scrub *sc, + xfs_agblock_t agbno, + xfs_extlen_t len) +{ + struct xfs_refcount_irec rc; + int has_refcount; + int error; + + if (!sc->sa.refc_cur || xchk_skip_xref(sc->sm)) + return; + + /* Find the CoW staging extent. */ + error = xfs_refcount_lookup_le(sc->sa.refc_cur, XFS_REFC_DOMAIN_COW, + agbno, &has_refcount); + if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur)) + return; + if (!has_refcount) { + xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0); + return; + } + + error = xfs_refcount_get_rec(sc->sa.refc_cur, &rc, &has_refcount); + if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur)) + return; + if (!has_refcount) { + xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0); + return; + } + + /* CoW lookup returned a shared extent record? */ + if (rc.rc_domain != XFS_REFC_DOMAIN_COW) + xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0); + + /* Must be at least as long as what was passed in */ + if (rc.rc_blockcount < len) + xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0); +} + +/* + * xref check that the extent is not shared. Only file data blocks + * can have multiple owners. + */ +void +xchk_xref_is_not_shared( + struct xfs_scrub *sc, + xfs_agblock_t agbno, + xfs_extlen_t len) +{ + enum xbtree_recpacking outcome; + int error; + + if (!sc->sa.refc_cur || xchk_skip_xref(sc->sm)) + return; + + error = xfs_refcount_has_records(sc->sa.refc_cur, + XFS_REFC_DOMAIN_SHARED, agbno, len, &outcome); + if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur)) + return; + if (outcome != XBTREE_RECPACKING_EMPTY) + xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0); +} + +/* xref check that the extent is not being used for CoW staging. */ +void +xchk_xref_is_not_cow_staging( + struct xfs_scrub *sc, + xfs_agblock_t agbno, + xfs_extlen_t len) +{ + enum xbtree_recpacking outcome; + int error; + + if (!sc->sa.refc_cur || xchk_skip_xref(sc->sm)) + return; + + error = xfs_refcount_has_records(sc->sa.refc_cur, XFS_REFC_DOMAIN_COW, + agbno, len, &outcome); + if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur)) + return; + if (outcome != XBTREE_RECPACKING_EMPTY) + xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0); +} -- cgit v1.2.3