// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright (C) 2018-2023 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_log_format.h" #include "xfs_trans.h" #include "xfs_sb.h" #include "xfs_inode.h" #include "xfs_alloc.h" #include "xfs_alloc_btree.h" #include "xfs_ialloc.h" #include "xfs_ialloc_btree.h" #include "xfs_rmap.h" #include "xfs_rmap_btree.h" #include "xfs_refcount_btree.h" #include "xfs_extent_busy.h" #include "xfs_ag.h" #include "xfs_ag_resv.h" #include "xfs_quota.h" #include "xfs_qm.h" #include "xfs_defer.h" #include "scrub/scrub.h" #include "scrub/common.h" #include "scrub/trace.h" #include "scrub/repair.h" #include "scrub/bitmap.h" #include "scrub/stats.h" /* * Attempt to repair some metadata, if the metadata is corrupt and userspace * told us to fix it. This function returns -EAGAIN to mean "re-run scrub", * and will set *fixed to true if it thinks it repaired anything. */ int xrep_attempt( struct xfs_scrub *sc, struct xchk_stats_run *run) { u64 repair_start; int error = 0; trace_xrep_attempt(XFS_I(file_inode(sc->file)), sc->sm, error); xchk_ag_btcur_free(&sc->sa); /* Repair whatever's broken. */ ASSERT(sc->ops->repair); run->repair_attempted = true; repair_start = xchk_stats_now(); error = sc->ops->repair(sc); trace_xrep_done(XFS_I(file_inode(sc->file)), sc->sm, error); run->repair_ns += xchk_stats_elapsed_ns(repair_start); switch (error) { case 0: /* * Repair succeeded. Commit the fixes and perform a second * scrub so that we can tell userspace if we fixed the problem. */ sc->sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT; sc->flags |= XREP_ALREADY_FIXED; run->repair_succeeded = true; return -EAGAIN; case -ECHRNG: sc->flags |= XCHK_NEED_DRAIN; run->retries++; return -EAGAIN; case -EDEADLOCK: /* Tell the caller to try again having grabbed all the locks. */ if (!(sc->flags & XCHK_TRY_HARDER)) { sc->flags |= XCHK_TRY_HARDER; run->retries++; return -EAGAIN; } /* * We tried harder but still couldn't grab all the resources * we needed to fix it. The corruption has not been fixed, * so exit to userspace with the scan's output flags unchanged. */ return 0; default: /* * EAGAIN tells the caller to re-scrub, so we cannot return * that here. */ ASSERT(error != -EAGAIN); return error; } } /* * Complain about unfixable problems in the filesystem. We don't log * corruptions when IFLAG_REPAIR wasn't set on the assumption that the driver * program is xfs_scrub, which will call back with IFLAG_REPAIR set if the * administrator isn't running xfs_scrub in no-repairs mode. * * Use this helper function because _ratelimited silently declares a static * structure to track rate limiting information. */ void xrep_failure( struct xfs_mount *mp) { xfs_alert_ratelimited(mp, "Corruption not fixed during online repair. Unmount and run xfs_repair."); } /* * Repair probe -- userspace uses this to probe if we're willing to repair a * given mountpoint. */ int xrep_probe( struct xfs_scrub *sc) { int error = 0; if (xchk_should_terminate(sc, &error)) return error; return 0; } /* * Roll a transaction, keeping the AG headers locked and reinitializing * the btree cursors. */ int xrep_roll_ag_trans( struct xfs_scrub *sc) { int error; /* * Keep the AG header buffers locked while we roll the transaction. * Ensure that both AG buffers are dirty and held when we roll the * transaction so that they move forward in the log without losing the * bli (and hence the bli type) when the transaction commits. * * Normal code would never hold clean buffers across a roll, but repair * needs both buffers to maintain a total lock on the AG. */ if (sc->sa.agi_bp) { xfs_ialloc_log_agi(sc->tp, sc->sa.agi_bp, XFS_AGI_MAGICNUM); xfs_trans_bhold(sc->tp, sc->sa.agi_bp); } if (sc->sa.agf_bp) { xfs_alloc_log_agf(sc->tp, sc->sa.agf_bp, XFS_AGF_MAGICNUM); xfs_trans_bhold(sc->tp, sc->sa.agf_bp); } /* * Roll the transaction. We still hold the AG header buffers locked * regardless of whether or not that succeeds. On failure, the buffers * will be released during teardown on our way out of the kernel. If * successful, join the buffers to the new transaction and move on. */ error = xfs_trans_roll(&sc->tp); if (error) return error; /* Join the AG headers to the new transaction. */ if (sc->sa.agi_bp) xfs_trans_bjoin(sc->tp, sc->sa.agi_bp); if (sc->sa.agf_bp) xfs_trans_bjoin(sc->tp, sc->sa.agf_bp); return 0; } /* Finish all deferred work attached to the repair transaction. */ int xrep_defer_finish( struct xfs_scrub *sc) { int error; /* * Keep the AG header buffers locked while we complete deferred work * items. Ensure that both AG buffers are dirty and held when we roll * the transaction so that they move forward in the log without losing * the bli (and hence the bli type) when the transaction commits. * * Normal code would never hold clean buffers across a roll, but repair * needs both buffers to maintain a total lock on the AG. */ if (sc->sa.agi_bp) { xfs_ialloc_log_agi(sc->tp, sc->sa.agi_bp, XFS_AGI_MAGICNUM); xfs_trans_bhold(sc->tp, sc->sa.agi_bp); } if (sc->sa.agf_bp) { xfs_alloc_log_agf(sc->tp, sc->sa.agf_bp, XFS_AGF_MAGICNUM); xfs_trans_bhold(sc->tp, sc->sa.agf_bp); } /* * Finish all deferred work items. We still hold the AG header buffers * locked regardless of whether or not that succeeds. On failure, the * buffers will be released during teardown on our way out of the * kernel. If successful, join the buffers to the new transaction * and move on. */ error = xfs_defer_finish(&sc->tp); if (error) return error; /* * Release the hold that we set above because defer_finish won't do * that for us. The defer roll code redirties held buffers after each * roll, so the AG header buffers should be ready for logging. */ if (sc->sa.agi_bp) xfs_trans_bhold_release(sc->tp, sc->sa.agi_bp); if (sc->sa.agf_bp) xfs_trans_bhold_release(sc->tp, sc->sa.agf_bp); return 0; } /* * Does the given AG have enough space to rebuild a btree? Neither AG * reservation can be critical, and we must have enough space (factoring * in AG reservations) to construct a whole btree. */ bool xrep_ag_has_space( struct xfs_perag *pag, xfs_extlen_t nr_blocks, enum xfs_ag_resv_type type) { return !xfs_ag_resv_critical(pag, XFS_AG_RESV_RMAPBT) && !xfs_ag_resv_critical(pag, XFS_AG_RESV_METADATA) && pag->pagf_freeblks > xfs_ag_resv_needed(pag, type) + nr_blocks; } /* * Figure out how many blocks to reserve for an AG repair. We calculate the * worst case estimate for the number of blocks we'd need to rebuild one of * any type of per-AG btree. */ xfs_extlen_t xrep_calc_ag_resblks( struct xfs_scrub *sc) { struct xfs_mount *mp = sc->mp; struct xfs_scrub_metadata *sm = sc->sm; struct xfs_perag *pag; struct xfs_buf *bp; xfs_agino_t icount = NULLAGINO; xfs_extlen_t aglen = NULLAGBLOCK; xfs_extlen_t usedlen; xfs_extlen_t freelen; xfs_extlen_t bnobt_sz; xfs_extlen_t inobt_sz; xfs_extlen_t rmapbt_sz; xfs_extlen_t refcbt_sz; int error; if (!(sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)) return 0; pag = xfs_perag_get(mp, sm->sm_agno); if (xfs_perag_initialised_agi(pag)) { /* Use in-core icount if possible. */ icount = pag->pagi_count; } else { /* Try to get the actual counters from disk. */ error = xfs_ialloc_read_agi(pag, NULL, &bp); if (!error) { icount = pag->pagi_count; xfs_buf_relse(bp); } } /* Now grab the block counters from the AGF. */ error = xfs_alloc_read_agf(pag, NULL, 0, &bp); if (error) { aglen = pag->block_count; freelen = aglen; usedlen = aglen; } else { struct xfs_agf *agf = bp->b_addr; aglen = be32_to_cpu(agf->agf_length); freelen = be32_to_cpu(agf->agf_freeblks); usedlen = aglen - freelen; xfs_buf_relse(bp); } /* If the icount is impossible, make some worst-case assumptions. */ if (icount == NULLAGINO || !xfs_verify_agino(pag, icount)) { icount = pag->agino_max - pag->agino_min + 1; } /* If the block counts are impossible, make worst-case assumptions. */ if (aglen == NULLAGBLOCK || aglen != pag->block_count || freelen >= aglen) { aglen = pag->block_count; freelen = aglen; usedlen = aglen; } xfs_perag_put(pag); trace_xrep_calc_ag_resblks(mp, sm->sm_agno, icount, aglen, freelen, usedlen); /* * Figure out how many blocks we'd need worst case to rebuild * each type of btree. Note that we can only rebuild the * bnobt/cntbt or inobt/finobt as pairs. */ bnobt_sz = 2 * xfs_allocbt_calc_size(mp, freelen); if (xfs_has_sparseinodes(mp)) inobt_sz = xfs_iallocbt_calc_size(mp, icount / XFS_INODES_PER_HOLEMASK_BIT); else inobt_sz = xfs_iallocbt_calc_size(mp, icount / XFS_INODES_PER_CHUNK); if (xfs_has_finobt(mp)) inobt_sz *= 2; if (xfs_has_reflink(mp)) refcbt_sz = xfs_refcountbt_calc_size(mp, usedlen); else refcbt_sz = 0; if (xfs_has_rmapbt(mp)) { /* * Guess how many blocks we need to rebuild the rmapbt. * For non-reflink filesystems we can't have more records than * used blocks. However, with reflink it's possible to have * more than one rmap record per AG block. We don't know how * many rmaps there could be in the AG, so we start off with * what we hope is an generous over-estimation. */ if (xfs_has_reflink(mp)) rmapbt_sz = xfs_rmapbt_calc_size(mp, (unsigned long long)aglen * 2); else rmapbt_sz = xfs_rmapbt_calc_size(mp, usedlen); } else { rmapbt_sz = 0; } trace_xrep_calc_ag_resblks_btsize(mp, sm->sm_agno, bnobt_sz, inobt_sz, rmapbt_sz, refcbt_sz); return max(max(bnobt_sz, inobt_sz), max(rmapbt_sz, refcbt_sz)); } /* * Reconstructing per-AG Btrees * * When a space btree is corrupt, we don't bother trying to fix it. Instead, * we scan secondary space metadata to derive the records that should be in * the damaged btree, initialize a fresh btree root, and insert the records. * Note that for rebuilding the rmapbt we scan all the primary data to * generate the new records. * * However, that leaves the matter of removing all the metadata describing the * old broken structure. For primary metadata we use the rmap data to collect * every extent with a matching rmap owner (bitmap); we then iterate all other * metadata structures with the same rmap owner to collect the extents that * cannot be removed (sublist). We then subtract sublist from bitmap to * derive the blocks that were used by the old btree. These blocks can be * reaped. * * For rmapbt reconstructions we must use different tactics for extent * collection. First we iterate all primary metadata (this excludes the old * rmapbt, obviously) to generate new rmap records. The gaps in the rmap * records are collected as bitmap. The bnobt records are collected as * sublist. As with the other btrees we subtract sublist from bitmap, and the * result (since the rmapbt lives in the free space) are the blocks from the * old rmapbt. */ /* Ensure the freelist is the correct size. */ int xrep_fix_freelist( struct xfs_scrub *sc, bool can_shrink) { struct xfs_alloc_arg args = {0}; args.mp = sc->mp; args.tp = sc->tp; args.agno = sc->sa.pag->pag_agno; args.alignment = 1; args.pag = sc->sa.pag; return xfs_alloc_fix_freelist(&args, can_shrink ? 0 : XFS_ALLOC_FLAG_NOSHRINK); } /* * Finding per-AG Btree Roots for AGF/AGI Reconstruction * * If the AGF or AGI become slightly corrupted, it may be necessary to rebuild * the AG headers by using the rmap data to rummage through the AG looking for * btree roots. This is not guaranteed to work if the AG is heavily damaged * or the rmap data are corrupt. * * Callers of xrep_find_ag_btree_roots must lock the AGF and AGFL * buffers if the AGF is being rebuilt; or the AGF and AGI buffers if the * AGI is being rebuilt. It must maintain these locks until it's safe for * other threads to change the btrees' shapes. The caller provides * information about the btrees to look for by passing in an array of * xrep_find_ag_btree with the (rmap owner, buf_ops, magic) fields set. * The (root, height) fields will be set on return if anything is found. The * last element of the array should have a NULL buf_ops to mark the end of the * array. * * For every rmapbt record matching any of the rmap owners in btree_info, * read each block referenced by the rmap record. If the block is a btree * block from this filesystem matching any of the magic numbers and has a * level higher than what we've already seen, remember the block and the * height of the tree required to have such a block. When the call completes, * we return the highest block we've found for each btree description; those * should be the roots. */ struct xrep_findroot { struct xfs_scrub *sc; struct xfs_buf *agfl_bp; struct xfs_agf *agf; struct xrep_find_ag_btree *btree_info; }; /* See if our block is in the AGFL. */ STATIC int xrep_findroot_agfl_walk( struct xfs_mount *mp, xfs_agblock_t bno, void *priv) { xfs_agblock_t *agbno = priv; return (*agbno == bno) ? -ECANCELED : 0; } /* Does this block match the btree information passed in? */ STATIC int xrep_findroot_block( struct xrep_findroot *ri, struct xrep_find_ag_btree *fab, uint64_t owner, xfs_agblock_t agbno, bool *done_with_block) { struct xfs_mount *mp = ri->sc->mp; struct xfs_buf *bp; struct xfs_btree_block *btblock; xfs_daddr_t daddr; int block_level; int error = 0; daddr = XFS_AGB_TO_DADDR(mp, ri->sc->sa.pag->pag_agno, agbno); /* * Blocks in the AGFL have stale contents that might just happen to * have a matching magic and uuid. We don't want to pull these blocks * in as part of a tree root, so we have to filter out the AGFL stuff * here. If the AGFL looks insane we'll just refuse to repair. */ if (owner == XFS_RMAP_OWN_AG) { error = xfs_agfl_walk(mp, ri->agf, ri->agfl_bp, xrep_findroot_agfl_walk, &agbno); if (error == -ECANCELED) return 0; if (error) return error; } /* * Read the buffer into memory so that we can see if it's a match for * our btree type. We have no clue if it is beforehand, and we want to * avoid xfs_trans_read_buf's behavior of dumping the DONE state (which * will cause needless disk reads in subsequent calls to this function) * and logging metadata verifier failures. * * Therefore, pass in NULL buffer ops. If the buffer was already in * memory from some other caller it will already have b_ops assigned. * If it was in memory from a previous unsuccessful findroot_block * call, the buffer won't have b_ops but it should be clean and ready * for us to try to verify if the read call succeeds. The same applies * if the buffer wasn't in memory at all. * * Note: If we never match a btree type with this buffer, it will be * left in memory with NULL b_ops. This shouldn't be a problem unless * the buffer gets written. */ error = xfs_trans_read_buf(mp, ri->sc->tp, mp->m_ddev_targp, daddr, mp->m_bsize, 0, &bp, NULL); if (error) return error; /* Ensure the block magic matches the btree type we're looking for. */ btblock = XFS_BUF_TO_BLOCK(bp); ASSERT(fab->buf_ops->magic[1] != 0); if (btblock->bb_magic != fab->buf_ops->magic[1]) goto out; /* * If the buffer already has ops applied and they're not the ones for * this btree type, we know this block doesn't match the btree and we * can bail out. * * If the buffer ops match ours, someone else has already validated * the block for us, so we can move on to checking if this is a root * block candidate. * * If the buffer does not have ops, nobody has successfully validated * the contents and the buffer cannot be dirty. If the magic, uuid, * and structure match this btree type then we'll move on to checking * if it's a root block candidate. If there is no match, bail out. */ if (bp->b_ops) { if (bp->b_ops != fab->buf_ops) goto out; } else { ASSERT(!xfs_trans_buf_is_dirty(bp)); if (!uuid_equal(&btblock->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid)) goto out; /* * Read verifiers can reference b_ops, so we set the pointer * here. If the verifier fails we'll reset the buffer state * to what it was before we touched the buffer. */ bp->b_ops = fab->buf_ops; fab->buf_ops->verify_read(bp); if (bp->b_error) { bp->b_ops = NULL; bp->b_error = 0; goto out; } /* * Some read verifiers will (re)set b_ops, so we must be * careful not to change b_ops after running the verifier. */ } /* * This block passes the magic/uuid and verifier tests for this btree * type. We don't need the caller to try the other tree types. */ *done_with_block = true; /* * Compare this btree block's level to the height of the current * candidate root block. * * If the level matches the root we found previously, throw away both * blocks because there can't be two candidate roots. * * If level is lower in the tree than the root we found previously, * ignore this block. */ block_level = xfs_btree_get_level(btblock); if (block_level + 1 == fab->height) { fab->root = NULLAGBLOCK; goto out; } else if (block_level < fab->height) { goto out; } /* * This is the highest block in the tree that we've found so far. * Update the btree height to reflect what we've learned from this * block. */ fab->height = block_level + 1; /* * If this block doesn't have sibling pointers, then it's the new root * block candidate. Otherwise, the root will be found farther up the * tree. */ if (btblock->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK) && btblock->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK)) fab->root = agbno; else fab->root = NULLAGBLOCK; trace_xrep_findroot_block(mp, ri->sc->sa.pag->pag_agno, agbno, be32_to_cpu(btblock->bb_magic), fab->height - 1); out: xfs_trans_brelse(ri->sc->tp, bp); return error; } /* * Do any of the blocks in this rmap record match one of the btrees we're * looking for? */ STATIC int xrep_findroot_rmap( struct xfs_btree_cur *cur, const struct xfs_rmap_irec *rec, void *priv) { struct xrep_findroot *ri = priv; struct xrep_find_ag_btree *fab; xfs_agblock_t b; bool done; int error = 0; /* Ignore anything that isn't AG metadata. */ if (!XFS_RMAP_NON_INODE_OWNER(rec->rm_owner)) return 0; /* Otherwise scan each block + btree type. */ for (b = 0; b < rec->rm_blockcount; b++) { done = false; for (fab = ri->btree_info; fab->buf_ops; fab++) { if (rec->rm_owner != fab->rmap_owner) continue; error = xrep_findroot_block(ri, fab, rec->rm_owner, rec->rm_startblock + b, &done); if (error) return error; if (done) break; } } return 0; } /* Find the roots of the per-AG btrees described in btree_info. */ int xrep_find_ag_btree_roots( struct xfs_scrub *sc, struct xfs_buf *agf_bp, struct xrep_find_ag_btree *btree_info, struct xfs_buf *agfl_bp) { struct xfs_mount *mp = sc->mp; struct xrep_findroot ri; struct xrep_find_ag_btree *fab; struct xfs_btree_cur *cur; int error; ASSERT(xfs_buf_islocked(agf_bp)); ASSERT(agfl_bp == NULL || xfs_buf_islocked(agfl_bp)); ri.sc = sc; ri.btree_info = btree_info; ri.agf = agf_bp->b_addr; ri.agfl_bp = agfl_bp; for (fab = btree_info; fab->buf_ops; fab++) { ASSERT(agfl_bp || fab->rmap_owner != XFS_RMAP_OWN_AG); ASSERT(XFS_RMAP_NON_INODE_OWNER(fab->rmap_owner)); fab->root = NULLAGBLOCK; fab->height = 0; } cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.pag); error = xfs_rmap_query_all(cur, xrep_findroot_rmap, &ri); xfs_btree_del_cursor(cur, error); return error; } /* Force a quotacheck the next time we mount. */ void xrep_force_quotacheck( struct xfs_scrub *sc, xfs_dqtype_t type) { uint flag; flag = xfs_quota_chkd_flag(type); if (!(flag & sc->mp->m_qflags)) return; mutex_lock(&sc->mp->m_quotainfo->qi_quotaofflock); sc->mp->m_qflags &= ~flag; spin_lock(&sc->mp->m_sb_lock); sc->mp->m_sb.sb_qflags &= ~flag; spin_unlock(&sc->mp->m_sb_lock); xfs_log_sb(sc->tp); mutex_unlock(&sc->mp->m_quotainfo->qi_quotaofflock); } /* * Attach dquots to this inode, or schedule quotacheck to fix them. * * This function ensures that the appropriate dquots are attached to an inode. * We cannot allow the dquot code to allocate an on-disk dquot block here * because we're already in transaction context with the inode locked. The * on-disk dquot should already exist anyway. If the quota code signals * corruption or missing quota information, schedule quotacheck, which will * repair corruptions in the quota metadata. */ int xrep_ino_dqattach( struct xfs_scrub *sc) { int error; error = xfs_qm_dqattach_locked(sc->ip, false); switch (error) { case -EFSBADCRC: case -EFSCORRUPTED: case -ENOENT: xfs_err_ratelimited(sc->mp, "inode %llu repair encountered quota error %d, quotacheck forced.", (unsigned long long)sc->ip->i_ino, error); if (XFS_IS_UQUOTA_ON(sc->mp) && !sc->ip->i_udquot) xrep_force_quotacheck(sc, XFS_DQTYPE_USER); if (XFS_IS_GQUOTA_ON(sc->mp) && !sc->ip->i_gdquot) xrep_force_quotacheck(sc, XFS_DQTYPE_GROUP); if (XFS_IS_PQUOTA_ON(sc->mp) && !sc->ip->i_pdquot) xrep_force_quotacheck(sc, XFS_DQTYPE_PROJ); fallthrough; case -ESRCH: error = 0; break; default: break; } return error; }