--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2018-2023 Oracle. All Rights Reserved.
+ */
+#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_defer.h"
+#include "xfs_btree.h"
+#include "xfs_btree_staging.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_alloc.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_rmap.h"
+#include "xfs_rmap_btree.h"
+#include "xfs_inode.h"
+#include "xfs_refcount.h"
+#include "xfs_extent_busy.h"
+#include "xfs_health.h"
+#include "xfs_bmap.h"
+#include "xfs_ialloc.h"
+#include "xfs_ag.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/btree.h"
+#include "scrub/trace.h"
+#include "scrub/repair.h"
+#include "scrub/bitmap.h"
+#include "scrub/agb_bitmap.h"
+#include "scrub/xfile.h"
+#include "scrub/xfarray.h"
+#include "scrub/newbt.h"
+#include "scrub/reap.h"
+
+/*
+ * Free Space Btree Repair
+ * =======================
+ *
+ * The reverse mappings are supposed to record all space usage for the entire
+ * AG. Therefore, we can recreate the free extent records in an AG by looking
+ * for gaps in the physical extents recorded in the rmapbt. These records are
+ * staged in @free_records. Identifying the gaps is more difficult on a
+ * reflink filesystem because rmap records are allowed to overlap.
+ *
+ * Because the final step of building a new index is to free the space used by
+ * the old index, repair needs to find that space. Unfortunately, all
+ * structures that live in the free space (bnobt, cntbt, rmapbt, agfl) share
+ * the same rmapbt owner code (OWN_AG), so this is not straightforward.
+ *
+ * The scan of the reverse mapping information records the space used by OWN_AG
+ * in @old_allocbt_blocks, which (at this stage) is somewhat misnamed. While
+ * walking the rmapbt records, we create a second bitmap @not_allocbt_blocks to
+ * record all visited rmap btree blocks and all blocks owned by the AGFL.
+ *
+ * After that is where the definitions of old_allocbt_blocks shifts. This
+ * expression identifies possible former bnobt/cntbt blocks:
+ *
+ * (OWN_AG blocks) & ~(rmapbt blocks | agfl blocks);
+ *
+ * Substituting from above definitions, that becomes:
+ *
+ * old_allocbt_blocks & ~not_allocbt_blocks
+ *
+ * The OWN_AG bitmap itself isn't needed after this point, so what we really do
+ * instead is:
+ *
+ * old_allocbt_blocks &= ~not_allocbt_blocks;
+ *
+ * After this point, @old_allocbt_blocks is a bitmap of alleged former
+ * bnobt/cntbt blocks. The xagb_bitmap_disunion operation modifies its first
+ * parameter in place to avoid copying records around.
+ *
+ * Next, some of the space described by @free_records are diverted to the newbt
+ * reservation and used to format new btree blocks. The remaining records are
+ * written to the new btree indices. We reconstruct both bnobt and cntbt at
+ * the same time since we've already done all the work.
+ *
+ * We use the prefix 'xrep_abt' here because we regenerate both free space
+ * allocation btrees at the same time.
+ */
+
+struct xrep_abt {
+ /* Blocks owned by the rmapbt or the agfl. */
+ struct xagb_bitmap not_allocbt_blocks;
+
+ /* All OWN_AG blocks. */
+ struct xagb_bitmap old_allocbt_blocks;
+
+ /*
+ * New bnobt information. All btree block reservations are added to
+ * the reservation list in new_bnobt.
+ */
+ struct xrep_newbt new_bnobt;
+
+ /* new cntbt information */
+ struct xrep_newbt new_cntbt;
+
+ /* Free space extents. */
+ struct xfarray *free_records;
+
+ struct xfs_scrub *sc;
+
+ /* Number of non-null records in @free_records. */
+ uint64_t nr_real_records;
+
+ /* get_records()'s position in the free space record array. */
+ xfarray_idx_t array_cur;
+
+ /*
+ * Next block we anticipate seeing in the rmap records. If the next
+ * rmap record is greater than next_agbno, we have found unused space.
+ */
+ xfs_agblock_t next_agbno;
+
+ /* Number of free blocks in this AG. */
+ xfs_agblock_t nr_blocks;
+
+ /* Longest free extent we found in the AG. */
+ xfs_agblock_t longest;
+};
+
+/* Set up to repair AG free space btrees. */
+int
+xrep_setup_ag_allocbt(
+ struct xfs_scrub *sc)
+{
+ unsigned int busy_gen;
+
+ /*
+ * Make sure the busy extent list is clear because we can't put extents
+ * on there twice.
+ */
+ busy_gen = READ_ONCE(sc->sa.pag->pagb_gen);
+ if (xfs_extent_busy_list_empty(sc->sa.pag))
+ return 0;
+
+ return xfs_extent_busy_flush(sc->tp, sc->sa.pag, busy_gen, 0);
+}
+
+/* Check for any obvious conflicts in the free extent. */
+STATIC int
+xrep_abt_check_free_ext(
+ struct xfs_scrub *sc,
+ const struct xfs_alloc_rec_incore *rec)
+{
+ enum xbtree_recpacking outcome;
+ int error;
+
+ if (xfs_alloc_check_irec(sc->sa.pag, rec) != NULL)
+ return -EFSCORRUPTED;
+
+ /* Must not be an inode chunk. */
+ error = xfs_ialloc_has_inodes_at_extent(sc->sa.ino_cur,
+ rec->ar_startblock, rec->ar_blockcount, &outcome);
+ if (error)
+ return error;
+ if (outcome != XBTREE_RECPACKING_EMPTY)
+ return -EFSCORRUPTED;
+
+ /* Must not be shared or CoW staging. */
+ if (sc->sa.refc_cur) {
+ error = xfs_refcount_has_records(sc->sa.refc_cur,
+ XFS_REFC_DOMAIN_SHARED, rec->ar_startblock,
+ rec->ar_blockcount, &outcome);
+ if (error)
+ return error;
+ if (outcome != XBTREE_RECPACKING_EMPTY)
+ return -EFSCORRUPTED;
+
+ error = xfs_refcount_has_records(sc->sa.refc_cur,
+ XFS_REFC_DOMAIN_COW, rec->ar_startblock,
+ rec->ar_blockcount, &outcome);
+ if (error)
+ return error;
+ if (outcome != XBTREE_RECPACKING_EMPTY)
+ return -EFSCORRUPTED;
+ }
+
+ return 0;
+}
+
+/*
+ * Stash a free space record for all the space since the last bno we found
+ * all the way up to @end.
+ */
+static int
+xrep_abt_stash(
+ struct xrep_abt *ra,
+ xfs_agblock_t end)
+{
+ struct xfs_alloc_rec_incore arec = {
+ .ar_startblock = ra->next_agbno,
+ .ar_blockcount = end - ra->next_agbno,
+ };
+ struct xfs_scrub *sc = ra->sc;
+ int error = 0;
+
+ if (xchk_should_terminate(sc, &error))
+ return error;
+
+ error = xrep_abt_check_free_ext(ra->sc, &arec);
+ if (error)
+ return error;
+
+ trace_xrep_abt_found(sc->mp, sc->sa.pag->pag_agno, &arec);
+
+ error = xfarray_append(ra->free_records, &arec);
+ if (error)
+ return error;
+
+ ra->nr_blocks += arec.ar_blockcount;
+ return 0;
+}
+
+/* Record extents that aren't in use from gaps in the rmap records. */
+STATIC int
+xrep_abt_walk_rmap(
+ struct xfs_btree_cur *cur,
+ const struct xfs_rmap_irec *rec,
+ void *priv)
+{
+ struct xrep_abt *ra = priv;
+ int error;
+
+ /* Record all the OWN_AG blocks... */
+ if (rec->rm_owner == XFS_RMAP_OWN_AG) {
+ error = xagb_bitmap_set(&ra->old_allocbt_blocks,
+ rec->rm_startblock, rec->rm_blockcount);
+ if (error)
+ return error;
+ }
+
+ /* ...and all the rmapbt blocks... */
+ error = xagb_bitmap_set_btcur_path(&ra->not_allocbt_blocks, cur);
+ if (error)
+ return error;
+
+ /* ...and all the free space. */
+ if (rec->rm_startblock > ra->next_agbno) {
+ error = xrep_abt_stash(ra, rec->rm_startblock);
+ if (error)
+ return error;
+ }
+
+ /*
+ * rmap records can overlap on reflink filesystems, so project
+ * next_agbno as far out into the AG space as we currently know about.
+ */
+ ra->next_agbno = max_t(xfs_agblock_t, ra->next_agbno,
+ rec->rm_startblock + rec->rm_blockcount);
+ return 0;
+}
+
+/* Collect an AGFL block for the not-to-release list. */
+static int
+xrep_abt_walk_agfl(
+ struct xfs_mount *mp,
+ xfs_agblock_t agbno,
+ void *priv)
+{
+ struct xrep_abt *ra = priv;
+
+ return xagb_bitmap_set(&ra->not_allocbt_blocks, agbno, 1);
+}
+
+/*
+ * Compare two free space extents by block number. We want to sort in order of
+ * increasing block number.
+ */
+static int
+xrep_bnobt_extent_cmp(
+ const void *a,
+ const void *b)
+{
+ const struct xfs_alloc_rec_incore *ap = a;
+ const struct xfs_alloc_rec_incore *bp = b;
+
+ if (ap->ar_startblock > bp->ar_startblock)
+ return 1;
+ else if (ap->ar_startblock < bp->ar_startblock)
+ return -1;
+ return 0;
+}
+
+/*
+ * Re-sort the free extents by block number so that we can put the records into
+ * the bnobt in the correct order. Make sure the records do not overlap in
+ * physical space.
+ */
+STATIC int
+xrep_bnobt_sort_records(
+ struct xrep_abt *ra)
+{
+ struct xfs_alloc_rec_incore arec;
+ xfarray_idx_t cur = XFARRAY_CURSOR_INIT;
+ xfs_agblock_t next_agbno = 0;
+ int error;
+
+ error = xfarray_sort(ra->free_records, xrep_bnobt_extent_cmp, 0);
+ if (error)
+ return error;
+
+ while ((error = xfarray_iter(ra->free_records, &cur, &arec)) == 1) {
+ if (arec.ar_startblock < next_agbno)
+ return -EFSCORRUPTED;
+
+ next_agbno = arec.ar_startblock + arec.ar_blockcount;
+ }
+
+ return error;
+}
+
+/*
+ * Compare two free space extents by length and then block number. We want
+ * to sort first in order of increasing length and then in order of increasing
+ * block number.
+ */
+static int
+xrep_cntbt_extent_cmp(
+ const void *a,
+ const void *b)
+{
+ const struct xfs_alloc_rec_incore *ap = a;
+ const struct xfs_alloc_rec_incore *bp = b;
+
+ if (ap->ar_blockcount > bp->ar_blockcount)
+ return 1;
+ else if (ap->ar_blockcount < bp->ar_blockcount)
+ return -1;
+ return xrep_bnobt_extent_cmp(a, b);
+}
+
+/*
+ * Sort the free extents by length so so that we can put the records into the
+ * cntbt in the correct order. Don't let userspace kill us if we're resorting
+ * after allocating btree blocks.
+ */
+STATIC int
+xrep_cntbt_sort_records(
+ struct xrep_abt *ra,
+ bool is_resort)
+{
+ return xfarray_sort(ra->free_records, xrep_cntbt_extent_cmp,
+ is_resort ? 0 : XFARRAY_SORT_KILLABLE);
+}
+
+/*
+ * Iterate all reverse mappings to find (1) the gaps between rmap records (all
+ * unowned space), (2) the OWN_AG extents (which encompass the free space
+ * btrees, the rmapbt, and the agfl), (3) the rmapbt blocks, and (4) the AGFL
+ * blocks. The free space is (1) + (2) - (3) - (4).
+ */
+STATIC int
+xrep_abt_find_freespace(
+ struct xrep_abt *ra)
+{
+ struct xfs_scrub *sc = ra->sc;
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_agf *agf = sc->sa.agf_bp->b_addr;
+ struct xfs_buf *agfl_bp;
+ xfs_agblock_t agend;
+ int error;
+
+ xagb_bitmap_init(&ra->not_allocbt_blocks);
+
+ xrep_ag_btcur_init(sc, &sc->sa);
+
+ /*
+ * Iterate all the reverse mappings to find gaps in the physical
+ * mappings, all the OWN_AG blocks, and all the rmapbt extents.
+ */
+ error = xfs_rmap_query_all(sc->sa.rmap_cur, xrep_abt_walk_rmap, ra);
+ if (error)
+ goto err;
+
+ /* Insert a record for space between the last rmap and EOAG. */
+ agend = be32_to_cpu(agf->agf_length);
+ if (ra->next_agbno < agend) {
+ error = xrep_abt_stash(ra, agend);
+ if (error)
+ goto err;
+ }
+
+ /* Collect all the AGFL blocks. */
+ error = xfs_alloc_read_agfl(sc->sa.pag, sc->tp, &agfl_bp);
+ if (error)
+ goto err;
+
+ error = xfs_agfl_walk(mp, agf, agfl_bp, xrep_abt_walk_agfl, ra);
+ if (error)
+ goto err_agfl;
+
+ /* Compute the old bnobt/cntbt blocks. */
+ error = xagb_bitmap_disunion(&ra->old_allocbt_blocks,
+ &ra->not_allocbt_blocks);
+ if (error)
+ goto err_agfl;
+
+ ra->nr_real_records = xfarray_length(ra->free_records);
+err_agfl:
+ xfs_trans_brelse(sc->tp, agfl_bp);
+err:
+ xchk_ag_btcur_free(&sc->sa);
+ xagb_bitmap_destroy(&ra->not_allocbt_blocks);
+ return error;
+}
+
+/*
+ * We're going to use the observed free space records to reserve blocks for the
+ * new free space btrees, so we play an iterative game where we try to converge
+ * on the number of blocks we need:
+ *
+ * 1. Estimate how many blocks we'll need to store the records.
+ * 2. If the first free record has more blocks than we need, we're done.
+ * We will have to re-sort the records prior to building the cntbt.
+ * 3. If that record has exactly the number of blocks we need, null out the
+ * record. We're done.
+ * 4. Otherwise, we still need more blocks. Null out the record, subtract its
+ * length from the number of blocks we need, and go back to step 1.
+ *
+ * Fortunately, we don't have to do any transaction work to play this game, so
+ * we don't have to tear down the staging cursors.
+ */
+STATIC int
+xrep_abt_reserve_space(
+ struct xrep_abt *ra,
+ struct xfs_btree_cur *bno_cur,
+ struct xfs_btree_cur *cnt_cur,
+ bool *needs_resort)
+{
+ struct xfs_scrub *sc = ra->sc;
+ xfarray_idx_t record_nr;
+ unsigned int allocated = 0;
+ int error = 0;
+
+ record_nr = xfarray_length(ra->free_records) - 1;
+ do {
+ struct xfs_alloc_rec_incore arec;
+ uint64_t required;
+ unsigned int desired;
+ unsigned int len;
+
+ /* Compute how many blocks we'll need. */
+ error = xfs_btree_bload_compute_geometry(cnt_cur,
+ &ra->new_cntbt.bload, ra->nr_real_records);
+ if (error)
+ break;
+
+ error = xfs_btree_bload_compute_geometry(bno_cur,
+ &ra->new_bnobt.bload, ra->nr_real_records);
+ if (error)
+ break;
+
+ /* How many btree blocks do we need to store all records? */
+ required = ra->new_bnobt.bload.nr_blocks +
+ ra->new_cntbt.bload.nr_blocks;
+ ASSERT(required < INT_MAX);
+
+ /* If we've reserved enough blocks, we're done. */
+ if (allocated >= required)
+ break;
+
+ desired = required - allocated;
+
+ /* We need space but there's none left; bye! */
+ if (ra->nr_real_records == 0) {
+ error = -ENOSPC;
+ break;
+ }
+
+ /* Grab the first record from the list. */
+ error = xfarray_load(ra->free_records, record_nr, &arec);
+ if (error)
+ break;
+
+ ASSERT(arec.ar_blockcount <= UINT_MAX);
+ len = min_t(unsigned int, arec.ar_blockcount, desired);
+
+ trace_xrep_newbt_alloc_ag_blocks(sc->mp, sc->sa.pag->pag_agno,
+ arec.ar_startblock, len, XFS_RMAP_OWN_AG);
+
+ error = xrep_newbt_add_extent(&ra->new_bnobt, sc->sa.pag,
+ arec.ar_startblock, len);
+ if (error)
+ break;
+ allocated += len;
+ ra->nr_blocks -= len;
+
+ if (arec.ar_blockcount > desired) {
+ /*
+ * Record has more space than we need. The number of
+ * free records doesn't change, so shrink the free
+ * record, inform the caller that the records are no
+ * longer sorted by length, and exit.
+ */
+ arec.ar_startblock += desired;
+ arec.ar_blockcount -= desired;
+ error = xfarray_store(ra->free_records, record_nr,
+ &arec);
+ if (error)
+ break;
+
+ *needs_resort = true;
+ return 0;
+ }
+
+ /*
+ * We're going to use up the entire record, so unset it and
+ * move on to the next one. This changes the number of free
+ * records (but doesn't break the sorting order), so we must
+ * go around the loop once more to re-run _bload_init.
+ */
+ error = xfarray_unset(ra->free_records, record_nr);
+ if (error)
+ break;
+ ra->nr_real_records--;
+ record_nr--;
+ } while (1);
+
+ return error;
+}
+
+STATIC int
+xrep_abt_dispose_one(
+ struct xrep_abt *ra,
+ struct xrep_newbt_resv *resv)
+{
+ struct xfs_scrub *sc = ra->sc;
+ struct xfs_perag *pag = sc->sa.pag;
+ xfs_agblock_t free_agbno = resv->agbno + resv->used;
+ xfs_extlen_t free_aglen = resv->len - resv->used;
+ int error;
+
+ ASSERT(pag == resv->pag);
+
+ /* Add a deferred rmap for each extent we used. */
+ if (resv->used > 0)
+ xfs_rmap_alloc_extent(sc->tp, pag->pag_agno, resv->agbno,
+ resv->used, XFS_RMAP_OWN_AG);
+
+ /*
+ * For each reserved btree block we didn't use, add it to the free
+ * space btree. We didn't touch fdblocks when we reserved them, so
+ * we don't touch it now.
+ */
+ if (free_aglen == 0)
+ return 0;
+
+ trace_xrep_newbt_free_blocks(sc->mp, resv->pag->pag_agno, free_agbno,
+ free_aglen, ra->new_bnobt.oinfo.oi_owner);
+
+ error = __xfs_free_extent(sc->tp, resv->pag, free_agbno, free_aglen,
+ &ra->new_bnobt.oinfo, XFS_AG_RESV_IGNORE, true);
+ if (error)
+ return error;
+
+ return xrep_defer_finish(sc);
+}
+
+/*
+ * Deal with all the space we reserved. Blocks that were allocated for the
+ * free space btrees need to have a (deferred) rmap added for the OWN_AG
+ * allocation, and blocks that didn't get used can be freed via the usual
+ * (deferred) means.
+ */
+STATIC void
+xrep_abt_dispose_reservations(
+ struct xrep_abt *ra,
+ int error)
+{
+ struct xrep_newbt_resv *resv, *n;
+
+ if (error)
+ goto junkit;
+
+ list_for_each_entry_safe(resv, n, &ra->new_bnobt.resv_list, list) {
+ error = xrep_abt_dispose_one(ra, resv);
+ if (error)
+ goto junkit;
+ }
+
+junkit:
+ list_for_each_entry_safe(resv, n, &ra->new_bnobt.resv_list, list) {
+ xfs_perag_put(resv->pag);
+ list_del(&resv->list);
+ kfree(resv);
+ }
+
+ xrep_newbt_cancel(&ra->new_bnobt);
+ xrep_newbt_cancel(&ra->new_cntbt);
+}
+
+/* Retrieve free space data for bulk load. */
+STATIC int
+xrep_abt_get_records(
+ struct xfs_btree_cur *cur,
+ unsigned int idx,
+ struct xfs_btree_block *block,
+ unsigned int nr_wanted,
+ void *priv)
+{
+ struct xfs_alloc_rec_incore *arec = &cur->bc_rec.a;
+ struct xrep_abt *ra = priv;
+ union xfs_btree_rec *block_rec;
+ unsigned int loaded;
+ int error;
+
+ for (loaded = 0; loaded < nr_wanted; loaded++, idx++) {
+ error = xfarray_load_next(ra->free_records, &ra->array_cur,
+ arec);
+ if (error)
+ return error;
+
+ ra->longest = max(ra->longest, arec->ar_blockcount);
+
+ block_rec = xfs_btree_rec_addr(cur, idx, block);
+ cur->bc_ops->init_rec_from_cur(cur, block_rec);
+ }
+
+ return loaded;
+}
+
+/* Feed one of the new btree blocks to the bulk loader. */
+STATIC int
+xrep_abt_claim_block(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_ptr *ptr,
+ void *priv)
+{
+ struct xrep_abt *ra = priv;
+
+ return xrep_newbt_claim_block(cur, &ra->new_bnobt, ptr);
+}
+
+/*
+ * Reset the AGF counters to reflect the free space btrees that we just
+ * rebuilt, then reinitialize the per-AG data.
+ */
+STATIC int
+xrep_abt_reset_counters(
+ struct xrep_abt *ra)
+{
+ struct xfs_scrub *sc = ra->sc;
+ struct xfs_perag *pag = sc->sa.pag;
+ struct xfs_agf *agf = sc->sa.agf_bp->b_addr;
+ unsigned int freesp_btreeblks = 0;
+
+ /*
+ * Compute the contribution to agf_btreeblks for the new free space
+ * btrees. This is the computed btree size minus anything we didn't
+ * use.
+ */
+ freesp_btreeblks += ra->new_bnobt.bload.nr_blocks - 1;
+ freesp_btreeblks += ra->new_cntbt.bload.nr_blocks - 1;
+
+ freesp_btreeblks -= xrep_newbt_unused_blocks(&ra->new_bnobt);
+ freesp_btreeblks -= xrep_newbt_unused_blocks(&ra->new_cntbt);
+
+ /*
+ * The AGF header contains extra information related to the free space
+ * btrees, so we must update those fields here.
+ */
+ agf->agf_btreeblks = cpu_to_be32(freesp_btreeblks +
+ (be32_to_cpu(agf->agf_rmap_blocks) - 1));
+ agf->agf_freeblks = cpu_to_be32(ra->nr_blocks);
+ agf->agf_longest = cpu_to_be32(ra->longest);
+ xfs_alloc_log_agf(sc->tp, sc->sa.agf_bp, XFS_AGF_BTREEBLKS |
+ XFS_AGF_LONGEST |
+ XFS_AGF_FREEBLKS);
+
+ /*
+ * After we commit the new btree to disk, it is possible that the
+ * process to reap the old btree blocks will race with the AIL trying
+ * to checkpoint the old btree blocks into the filesystem. If the new
+ * tree is shorter than the old one, the allocbt write verifier will
+ * fail and the AIL will shut down the filesystem.
+ *
+ * To avoid this, save the old incore btree height values as the alt
+ * height values before re-initializing the perag info from the updated
+ * AGF to capture all the new values.
+ */
+ pag->pagf_repair_levels[XFS_BTNUM_BNOi] = pag->pagf_levels[XFS_BTNUM_BNOi];
+ pag->pagf_repair_levels[XFS_BTNUM_CNTi] = pag->pagf_levels[XFS_BTNUM_CNTi];
+
+ /* Reinitialize with the values we just logged. */
+ return xrep_reinit_pagf(sc);
+}
+
+/*
+ * Use the collected free space information to stage new free space btrees.
+ * If this is successful we'll return with the new btree root
+ * information logged to the repair transaction but not yet committed.
+ */
+STATIC int
+xrep_abt_build_new_trees(
+ struct xrep_abt *ra)
+{
+ struct xfs_scrub *sc = ra->sc;
+ struct xfs_btree_cur *bno_cur;
+ struct xfs_btree_cur *cnt_cur;
+ struct xfs_perag *pag = sc->sa.pag;
+ bool needs_resort = false;
+ int error;
+
+ /*
+ * Sort the free extents by length so that we can set up the free space
+ * btrees in as few extents as possible. This reduces the amount of
+ * deferred rmap / free work we have to do at the end.
+ */
+ error = xrep_cntbt_sort_records(ra, false);
+ if (error)
+ return error;
+
+ /*
+ * Prepare to construct the new btree by reserving disk space for the
+ * new btree and setting up all the accounting information we'll need
+ * to root the new btree while it's under construction and before we
+ * attach it to the AG header.
+ */
+ xrep_newbt_init_bare(&ra->new_bnobt, sc);
+ xrep_newbt_init_bare(&ra->new_cntbt, sc);
+
+ ra->new_bnobt.bload.get_records = xrep_abt_get_records;
+ ra->new_cntbt.bload.get_records = xrep_abt_get_records;
+
+ ra->new_bnobt.bload.claim_block = xrep_abt_claim_block;
+ ra->new_cntbt.bload.claim_block = xrep_abt_claim_block;
+
+ /* Allocate cursors for the staged btrees. */
+ bno_cur = xfs_allocbt_stage_cursor(sc->mp, &ra->new_bnobt.afake,
+ pag, XFS_BTNUM_BNO);
+ cnt_cur = xfs_allocbt_stage_cursor(sc->mp, &ra->new_cntbt.afake,
+ pag, XFS_BTNUM_CNT);
+
+ /* Last chance to abort before we start committing fixes. */
+ if (xchk_should_terminate(sc, &error))
+ goto err_cur;
+
+ /* Reserve the space we'll need for the new btrees. */
+ error = xrep_abt_reserve_space(ra, bno_cur, cnt_cur, &needs_resort);
+ if (error)
+ goto err_cur;
+
+ /*
+ * If we need to re-sort the free extents by length, do so so that we
+ * can put the records into the cntbt in the correct order.
+ */
+ if (needs_resort) {
+ error = xrep_cntbt_sort_records(ra, needs_resort);
+ if (error)
+ goto err_cur;
+ }
+
+ /*
+ * Due to btree slack factors, it's possible for a new btree to be one
+ * level taller than the old btree. Update the alternate incore btree
+ * height so that we don't trip the verifiers when writing the new
+ * btree blocks to disk.
+ */
+ pag->pagf_repair_levels[XFS_BTNUM_BNOi] =
+ ra->new_bnobt.bload.btree_height;
+ pag->pagf_repair_levels[XFS_BTNUM_CNTi] =
+ ra->new_cntbt.bload.btree_height;
+
+ /* Load the free space by length tree. */
+ ra->array_cur = XFARRAY_CURSOR_INIT;
+ ra->longest = 0;
+ error = xfs_btree_bload(cnt_cur, &ra->new_cntbt.bload, ra);
+ if (error)
+ goto err_levels;
+
+ error = xrep_bnobt_sort_records(ra);
+ if (error)
+ return error;
+
+ /* Load the free space by block number tree. */
+ ra->array_cur = XFARRAY_CURSOR_INIT;
+ error = xfs_btree_bload(bno_cur, &ra->new_bnobt.bload, ra);
+ if (error)
+ goto err_levels;
+
+ /*
+ * Install the new btrees in the AG header. After this point the old
+ * btrees are no longer accessible and the new trees are live.
+ */
+ xfs_allocbt_commit_staged_btree(bno_cur, sc->tp, sc->sa.agf_bp);
+ xfs_btree_del_cursor(bno_cur, 0);
+ xfs_allocbt_commit_staged_btree(cnt_cur, sc->tp, sc->sa.agf_bp);
+ xfs_btree_del_cursor(cnt_cur, 0);
+
+ /* Reset the AGF counters now that we've changed the btree shape. */
+ error = xrep_abt_reset_counters(ra);
+ if (error)
+ goto err_newbt;
+
+ /* Dispose of any unused blocks and the accounting information. */
+ xrep_abt_dispose_reservations(ra, error);
+
+ return xrep_roll_ag_trans(sc);
+
+err_levels:
+ pag->pagf_repair_levels[XFS_BTNUM_BNOi] = 0;
+ pag->pagf_repair_levels[XFS_BTNUM_CNTi] = 0;
+err_cur:
+ xfs_btree_del_cursor(cnt_cur, error);
+ xfs_btree_del_cursor(bno_cur, error);
+err_newbt:
+ xrep_abt_dispose_reservations(ra, error);
+ return error;
+}
+
+/*
+ * Now that we've logged the roots of the new btrees, invalidate all of the
+ * old blocks and free them.
+ */
+STATIC int
+xrep_abt_remove_old_trees(
+ struct xrep_abt *ra)
+{
+ struct xfs_perag *pag = ra->sc->sa.pag;
+ int error;
+
+ /* Free the old btree blocks if they're not in use. */
+ error = xrep_reap_agblocks(ra->sc, &ra->old_allocbt_blocks,
+ &XFS_RMAP_OINFO_AG, XFS_AG_RESV_IGNORE);
+ if (error)
+ return error;
+
+ /*
+ * Now that we've zapped all the old allocbt blocks we can turn off
+ * the alternate height mechanism.
+ */
+ pag->pagf_repair_levels[XFS_BTNUM_BNOi] = 0;
+ pag->pagf_repair_levels[XFS_BTNUM_CNTi] = 0;
+ return 0;
+}
+
+/* Repair the freespace btrees for some AG. */
+int
+xrep_allocbt(
+ struct xfs_scrub *sc)
+{
+ struct xrep_abt *ra;
+ struct xfs_mount *mp = sc->mp;
+ char *descr;
+ int error;
+
+ /* We require the rmapbt to rebuild anything. */
+ if (!xfs_has_rmapbt(mp))
+ return -EOPNOTSUPP;
+
+ ra = kzalloc(sizeof(struct xrep_abt), XCHK_GFP_FLAGS);
+ if (!ra)
+ return -ENOMEM;
+ ra->sc = sc;
+
+ /* We rebuild both data structures. */
+ sc->sick_mask = XFS_SICK_AG_BNOBT | XFS_SICK_AG_CNTBT;
+
+ /*
+ * Make sure the busy extent list is clear because we can't put extents
+ * on there twice. In theory we cleared this before we started, but
+ * let's not risk the filesystem.
+ */
+ if (!xfs_extent_busy_list_empty(sc->sa.pag)) {
+ error = -EDEADLOCK;
+ goto out_ra;
+ }
+
+ /* Set up enough storage to handle maximally fragmented free space. */
+ descr = xchk_xfile_ag_descr(sc, "free space records");
+ error = xfarray_create(descr, mp->m_sb.sb_agblocks / 2,
+ sizeof(struct xfs_alloc_rec_incore),
+ &ra->free_records);
+ kfree(descr);
+ if (error)
+ goto out_ra;
+
+ /* Collect the free space data and find the old btree blocks. */
+ xagb_bitmap_init(&ra->old_allocbt_blocks);
+ error = xrep_abt_find_freespace(ra);
+ if (error)
+ goto out_bitmap;
+
+ /* Rebuild the free space information. */
+ error = xrep_abt_build_new_trees(ra);
+ if (error)
+ goto out_bitmap;
+
+ /* Kill the old trees. */
+ error = xrep_abt_remove_old_trees(ra);
+ if (error)
+ goto out_bitmap;
+
+out_bitmap:
+ xagb_bitmap_destroy(&ra->old_allocbt_blocks);
+ xfarray_destroy(ra->free_records);
+out_ra:
+ kfree(ra);
+ return error;
+}
+
+/* Make sure both btrees are ok after we've rebuilt them. */
+int
+xrep_revalidate_allocbt(
+ struct xfs_scrub *sc)
+{
+ __u32 old_type = sc->sm->sm_type;
+ int error;
+
+ /*
+ * We must update sm_type temporarily so that the tree-to-tree cross
+ * reference checks will work in the correct direction, and also so
+ * that tracing will report correctly if there are more errors.
+ */
+ sc->sm->sm_type = XFS_SCRUB_TYPE_BNOBT;
+ error = xchk_allocbt(sc);
+ if (error)
+ goto out;
+
+ sc->sm->sm_type = XFS_SCRUB_TYPE_CNTBT;
+ error = xchk_allocbt(sc);
+out:
+ sc->sm->sm_type = old_type;
+ return error;
+}
projects / linux.git / commitdiff