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Diffstat (limited to 'fs/xfs/scrub/common.c')
| -rw-r--r-- | fs/xfs/scrub/common.c | 1384 |
1 files changed, 1384 insertions, 0 deletions
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c new file mode 100644 index 0000000000..de24532fe0 --- /dev/null +++ b/fs/xfs/scrub/common.c @@ -0,0 +1,1384 @@ +// 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_log_format.h" +#include "xfs_trans.h" +#include "xfs_inode.h" +#include "xfs_icache.h" +#include "xfs_alloc.h" +#include "xfs_alloc_btree.h" +#include "xfs_ialloc.h" +#include "xfs_ialloc_btree.h" +#include "xfs_refcount_btree.h" +#include "xfs_rmap.h" +#include "xfs_rmap_btree.h" +#include "xfs_log.h" +#include "xfs_trans_priv.h" +#include "xfs_da_format.h" +#include "xfs_da_btree.h" +#include "xfs_attr.h" +#include "xfs_reflink.h" +#include "xfs_ag.h" +#include "scrub/scrub.h" +#include "scrub/common.h" +#include "scrub/trace.h" +#include "scrub/repair.h" +#include "scrub/health.h" + +/* Common code for the metadata scrubbers. */ + +/* + * Handling operational errors. + * + * The *_process_error() family of functions are used to process error return + * codes from functions called as part of a scrub operation. + * + * If there's no error, we return true to tell the caller that it's ok + * to move on to the next check in its list. + * + * For non-verifier errors (e.g. ENOMEM) we return false to tell the + * caller that something bad happened, and we preserve *error so that + * the caller can return the *error up the stack to userspace. + * + * Verifier errors (EFSBADCRC/EFSCORRUPTED) are recorded by setting + * OFLAG_CORRUPT in sm_flags and the *error is cleared. In other words, + * we track verifier errors (and failed scrub checks) via OFLAG_CORRUPT, + * not via return codes. We return false to tell the caller that + * something bad happened. Since the error has been cleared, the caller + * will (presumably) return that zero and scrubbing will move on to + * whatever's next. + * + * ftrace can be used to record the precise metadata location and the + * approximate code location of the failed operation. + */ + +/* Check for operational errors. */ +static bool +__xchk_process_error( + struct xfs_scrub *sc, + xfs_agnumber_t agno, + xfs_agblock_t bno, + int *error, + __u32 errflag, + void *ret_ip) +{ + switch (*error) { + case 0: + return true; + case -EDEADLOCK: + case -ECHRNG: + /* Used to restart an op with deadlock avoidance. */ + trace_xchk_deadlock_retry( + sc->ip ? sc->ip : XFS_I(file_inode(sc->file)), + sc->sm, *error); + break; + case -EFSBADCRC: + case -EFSCORRUPTED: + /* Note the badness but don't abort. */ + sc->sm->sm_flags |= errflag; + *error = 0; + fallthrough; + default: + trace_xchk_op_error(sc, agno, bno, *error, + ret_ip); + break; + } + return false; +} + +bool +xchk_process_error( + struct xfs_scrub *sc, + xfs_agnumber_t agno, + xfs_agblock_t bno, + int *error) +{ + return __xchk_process_error(sc, agno, bno, error, + XFS_SCRUB_OFLAG_CORRUPT, __return_address); +} + +bool +xchk_xref_process_error( + struct xfs_scrub *sc, + xfs_agnumber_t agno, + xfs_agblock_t bno, + int *error) +{ + return __xchk_process_error(sc, agno, bno, error, + XFS_SCRUB_OFLAG_XFAIL, __return_address); +} + +/* Check for operational errors for a file offset. */ +static bool +__xchk_fblock_process_error( + struct xfs_scrub *sc, + int whichfork, + xfs_fileoff_t offset, + int *error, + __u32 errflag, + void *ret_ip) +{ + switch (*error) { + case 0: + return true; + case -EDEADLOCK: + case -ECHRNG: + /* Used to restart an op with deadlock avoidance. */ + trace_xchk_deadlock_retry(sc->ip, sc->sm, *error); + break; + case -EFSBADCRC: + case -EFSCORRUPTED: + /* Note the badness but don't abort. */ + sc->sm->sm_flags |= errflag; + *error = 0; + fallthrough; + default: + trace_xchk_file_op_error(sc, whichfork, offset, *error, + ret_ip); + break; + } + return false; +} + +bool +xchk_fblock_process_error( + struct xfs_scrub *sc, + int whichfork, + xfs_fileoff_t offset, + int *error) +{ + return __xchk_fblock_process_error(sc, whichfork, offset, error, + XFS_SCRUB_OFLAG_CORRUPT, __return_address); +} + +bool +xchk_fblock_xref_process_error( + struct xfs_scrub *sc, + int whichfork, + xfs_fileoff_t offset, + int *error) +{ + return __xchk_fblock_process_error(sc, whichfork, offset, error, + XFS_SCRUB_OFLAG_XFAIL, __return_address); +} + +/* + * Handling scrub corruption/optimization/warning checks. + * + * The *_set_{corrupt,preen,warning}() family of functions are used to + * record the presence of metadata that is incorrect (corrupt), could be + * optimized somehow (preen), or should be flagged for administrative + * review but is not incorrect (warn). + * + * ftrace can be used to record the precise metadata location and + * approximate code location of the failed check. + */ + +/* Record a block which could be optimized. */ +void +xchk_block_set_preen( + struct xfs_scrub *sc, + struct xfs_buf *bp) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_PREEN; + trace_xchk_block_preen(sc, xfs_buf_daddr(bp), __return_address); +} + +/* + * Record an inode which could be optimized. The trace data will + * include the block given by bp if bp is given; otherwise it will use + * the block location of the inode record itself. + */ +void +xchk_ino_set_preen( + struct xfs_scrub *sc, + xfs_ino_t ino) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_PREEN; + trace_xchk_ino_preen(sc, ino, __return_address); +} + +/* Record something being wrong with the filesystem primary superblock. */ +void +xchk_set_corrupt( + struct xfs_scrub *sc) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT; + trace_xchk_fs_error(sc, 0, __return_address); +} + +/* Record a corrupt block. */ +void +xchk_block_set_corrupt( + struct xfs_scrub *sc, + struct xfs_buf *bp) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT; + trace_xchk_block_error(sc, xfs_buf_daddr(bp), __return_address); +} + +/* Record a corruption while cross-referencing. */ +void +xchk_block_xref_set_corrupt( + struct xfs_scrub *sc, + struct xfs_buf *bp) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT; + trace_xchk_block_error(sc, xfs_buf_daddr(bp), __return_address); +} + +/* + * Record a corrupt inode. The trace data will include the block given + * by bp if bp is given; otherwise it will use the block location of the + * inode record itself. + */ +void +xchk_ino_set_corrupt( + struct xfs_scrub *sc, + xfs_ino_t ino) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT; + trace_xchk_ino_error(sc, ino, __return_address); +} + +/* Record a corruption while cross-referencing with an inode. */ +void +xchk_ino_xref_set_corrupt( + struct xfs_scrub *sc, + xfs_ino_t ino) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT; + trace_xchk_ino_error(sc, ino, __return_address); +} + +/* Record corruption in a block indexed by a file fork. */ +void +xchk_fblock_set_corrupt( + struct xfs_scrub *sc, + int whichfork, + xfs_fileoff_t offset) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT; + trace_xchk_fblock_error(sc, whichfork, offset, __return_address); +} + +/* Record a corruption while cross-referencing a fork block. */ +void +xchk_fblock_xref_set_corrupt( + struct xfs_scrub *sc, + int whichfork, + xfs_fileoff_t offset) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT; + trace_xchk_fblock_error(sc, whichfork, offset, __return_address); +} + +/* + * Warn about inodes that need administrative review but is not + * incorrect. + */ +void +xchk_ino_set_warning( + struct xfs_scrub *sc, + xfs_ino_t ino) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_WARNING; + trace_xchk_ino_warning(sc, ino, __return_address); +} + +/* Warn about a block indexed by a file fork that needs review. */ +void +xchk_fblock_set_warning( + struct xfs_scrub *sc, + int whichfork, + xfs_fileoff_t offset) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_WARNING; + trace_xchk_fblock_warning(sc, whichfork, offset, __return_address); +} + +/* Signal an incomplete scrub. */ +void +xchk_set_incomplete( + struct xfs_scrub *sc) +{ + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_INCOMPLETE; + trace_xchk_incomplete(sc, __return_address); +} + +/* + * rmap scrubbing -- compute the number of blocks with a given owner, + * at least according to the reverse mapping data. + */ + +struct xchk_rmap_ownedby_info { + const struct xfs_owner_info *oinfo; + xfs_filblks_t *blocks; +}; + +STATIC int +xchk_count_rmap_ownedby_irec( + struct xfs_btree_cur *cur, + const struct xfs_rmap_irec *rec, + void *priv) +{ + struct xchk_rmap_ownedby_info *sroi = priv; + bool irec_attr; + bool oinfo_attr; + + irec_attr = rec->rm_flags & XFS_RMAP_ATTR_FORK; + oinfo_attr = sroi->oinfo->oi_flags & XFS_OWNER_INFO_ATTR_FORK; + + if (rec->rm_owner != sroi->oinfo->oi_owner) + return 0; + + if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner) || irec_attr == oinfo_attr) + (*sroi->blocks) += rec->rm_blockcount; + + return 0; +} + +/* + * Calculate the number of blocks the rmap thinks are owned by something. + * The caller should pass us an rmapbt cursor. + */ +int +xchk_count_rmap_ownedby_ag( + struct xfs_scrub *sc, + struct xfs_btree_cur *cur, + const struct xfs_owner_info *oinfo, + xfs_filblks_t *blocks) +{ + struct xchk_rmap_ownedby_info sroi = { + .oinfo = oinfo, + .blocks = blocks, + }; + + *blocks = 0; + return xfs_rmap_query_all(cur, xchk_count_rmap_ownedby_irec, + &sroi); +} + +/* + * AG scrubbing + * + * These helpers facilitate locking an allocation group's header + * buffers, setting up cursors for all btrees that are present, and + * cleaning everything up once we're through. + */ + +/* Decide if we want to return an AG header read failure. */ +static inline bool +want_ag_read_header_failure( + struct xfs_scrub *sc, + unsigned int type) +{ + /* Return all AG header read failures when scanning btrees. */ + if (sc->sm->sm_type != XFS_SCRUB_TYPE_AGF && + sc->sm->sm_type != XFS_SCRUB_TYPE_AGFL && + sc->sm->sm_type != XFS_SCRUB_TYPE_AGI) + return true; + /* + * If we're scanning a given type of AG header, we only want to + * see read failures from that specific header. We'd like the + * other headers to cross-check them, but this isn't required. + */ + if (sc->sm->sm_type == type) + return true; + return false; +} + +/* + * Grab the AG header buffers for the attached perag structure. + * + * The headers should be released by xchk_ag_free, but as a fail safe we attach + * all the buffers we grab to the scrub transaction so they'll all be freed + * when we cancel it. + */ +static inline int +xchk_perag_read_headers( + struct xfs_scrub *sc, + struct xchk_ag *sa) +{ + int error; + + error = xfs_ialloc_read_agi(sa->pag, sc->tp, &sa->agi_bp); + if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGI)) + return error; + + error = xfs_alloc_read_agf(sa->pag, sc->tp, 0, &sa->agf_bp); + if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGF)) + return error; + + return 0; +} + +/* + * Grab the AG headers for the attached perag structure and wait for pending + * intents to drain. + */ +static int +xchk_perag_drain_and_lock( + struct xfs_scrub *sc) +{ + struct xchk_ag *sa = &sc->sa; + int error = 0; + + ASSERT(sa->pag != NULL); + ASSERT(sa->agi_bp == NULL); + ASSERT(sa->agf_bp == NULL); + + do { + if (xchk_should_terminate(sc, &error)) + return error; + + error = xchk_perag_read_headers(sc, sa); + if (error) + return error; + + /* + * If we've grabbed an inode for scrubbing then we assume that + * holding its ILOCK will suffice to coordinate with any intent + * chains involving this inode. + */ + if (sc->ip) + return 0; + + /* + * Decide if this AG is quiet enough for all metadata to be + * consistent with each other. XFS allows the AG header buffer + * locks to cycle across transaction rolls while processing + * chains of deferred ops, which means that there could be + * other threads in the middle of processing a chain of + * deferred ops. For regular operations we are careful about + * ordering operations to prevent collisions between threads + * (which is why we don't need a per-AG lock), but scrub and + * repair have to serialize against chained operations. + * + * We just locked all the AG headers buffers; now take a look + * to see if there are any intents in progress. If there are, + * drop the AG headers and wait for the intents to drain. + * Since we hold all the AG header locks for the duration of + * the scrub, this is the only time we have to sample the + * intents counter; any threads increasing it after this point + * can't possibly be in the middle of a chain of AG metadata + * updates. + * + * Obviously, this should be slanted against scrub and in favor + * of runtime threads. + */ + if (!xfs_perag_intent_busy(sa->pag)) + return 0; + + if (sa->agf_bp) { + xfs_trans_brelse(sc->tp, sa->agf_bp); + sa->agf_bp = NULL; + } + + if (sa->agi_bp) { + xfs_trans_brelse(sc->tp, sa->agi_bp); + sa->agi_bp = NULL; + } + + if (!(sc->flags & XCHK_FSGATES_DRAIN)) + return -ECHRNG; + error = xfs_perag_intent_drain(sa->pag); + if (error == -ERESTARTSYS) + error = -EINTR; + } while (!error); + + return error; +} + +/* + * Grab the per-AG structure, grab all AG header buffers, and wait until there + * aren't any pending intents. Returns -ENOENT if we can't grab the perag + * structure. + */ +int +xchk_ag_read_headers( + struct xfs_scrub *sc, + xfs_agnumber_t agno, + struct xchk_ag *sa) +{ + struct xfs_mount *mp = sc->mp; + + ASSERT(!sa->pag); + sa->pag = xfs_perag_get(mp, agno); + if (!sa->pag) + return -ENOENT; + + return xchk_perag_drain_and_lock(sc); +} + +/* Release all the AG btree cursors. */ +void +xchk_ag_btcur_free( + struct xchk_ag *sa) +{ + if (sa->refc_cur) + xfs_btree_del_cursor(sa->refc_cur, XFS_BTREE_ERROR); + if (sa->rmap_cur) + xfs_btree_del_cursor(sa->rmap_cur, XFS_BTREE_ERROR); + if (sa->fino_cur) + xfs_btree_del_cursor(sa->fino_cur, XFS_BTREE_ERROR); + if (sa->ino_cur) + xfs_btree_del_cursor(sa->ino_cur, XFS_BTREE_ERROR); + if (sa->cnt_cur) + xfs_btree_del_cursor(sa->cnt_cur, XFS_BTREE_ERROR); + if (sa->bno_cur) + xfs_btree_del_cursor(sa->bno_cur, XFS_BTREE_ERROR); + + sa->refc_cur = NULL; + sa->rmap_cur = NULL; + sa->fino_cur = NULL; + sa->ino_cur = NULL; + sa->bno_cur = NULL; + sa->cnt_cur = NULL; +} + +/* Initialize all the btree cursors for an AG. */ +void +xchk_ag_btcur_init( + struct xfs_scrub *sc, + struct xchk_ag *sa) +{ + struct xfs_mount *mp = sc->mp; + + if (sa->agf_bp && + xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_BNO)) { + /* Set up a bnobt cursor for cross-referencing. */ + sa->bno_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp, + sa->pag, XFS_BTNUM_BNO); + } + + if (sa->agf_bp && + xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_CNT)) { + /* Set up a cntbt cursor for cross-referencing. */ + sa->cnt_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp, + sa->pag, XFS_BTNUM_CNT); + } + + /* Set up a inobt cursor for cross-referencing. */ + if (sa->agi_bp && + xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_INO)) { + sa->ino_cur = xfs_inobt_init_cursor(sa->pag, sc->tp, sa->agi_bp, + XFS_BTNUM_INO); + } + + /* Set up a finobt cursor for cross-referencing. */ + if (sa->agi_bp && xfs_has_finobt(mp) && + xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_FINO)) { + sa->fino_cur = xfs_inobt_init_cursor(sa->pag, sc->tp, sa->agi_bp, + XFS_BTNUM_FINO); + } + + /* Set up a rmapbt cursor for cross-referencing. */ + if (sa->agf_bp && xfs_has_rmapbt(mp) && + xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_RMAP)) { + sa->rmap_cur = xfs_rmapbt_init_cursor(mp, sc->tp, sa->agf_bp, + sa->pag); + } + + /* Set up a refcountbt cursor for cross-referencing. */ + if (sa->agf_bp && xfs_has_reflink(mp) && + xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_REFC)) { + sa->refc_cur = xfs_refcountbt_init_cursor(mp, sc->tp, + sa->agf_bp, sa->pag); + } +} + +/* Release the AG header context and btree cursors. */ +void +xchk_ag_free( + struct xfs_scrub *sc, + struct xchk_ag *sa) +{ + xchk_ag_btcur_free(sa); + if (sa->agf_bp) { + xfs_trans_brelse(sc->tp, sa->agf_bp); + sa->agf_bp = NULL; + } + if (sa->agi_bp) { + xfs_trans_brelse(sc->tp, sa->agi_bp); + sa->agi_bp = NULL; + } + if (sa->pag) { + xfs_perag_put(sa->pag); + sa->pag = NULL; + } +} + +/* + * For scrub, grab the perag structure, the AGI, and the AGF headers, in that + * order. Locking order requires us to get the AGI before the AGF. We use the + * transaction to avoid deadlocking on crosslinked metadata buffers; either the + * caller passes one in (bmap scrub) or we have to create a transaction + * ourselves. Returns ENOENT if the perag struct cannot be grabbed. + */ +int +xchk_ag_init( + struct xfs_scrub *sc, + xfs_agnumber_t agno, + struct xchk_ag *sa) +{ + int error; + + error = xchk_ag_read_headers(sc, agno, sa); + if (error) + return error; + + xchk_ag_btcur_init(sc, sa); + return 0; +} + +/* Per-scrubber setup functions */ + +void +xchk_trans_cancel( + struct xfs_scrub *sc) +{ + xfs_trans_cancel(sc->tp); + sc->tp = NULL; +} + +/* + * Grab an empty transaction so that we can re-grab locked buffers if + * one of our btrees turns out to be cyclic. + * + * If we're going to repair something, we need to ask for the largest possible + * log reservation so that we can handle the worst case scenario for metadata + * updates while rebuilding a metadata item. We also need to reserve as many + * blocks in the head transaction as we think we're going to need to rebuild + * the metadata object. + */ +int +xchk_trans_alloc( + struct xfs_scrub *sc, + uint resblks) +{ + if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) + return xfs_trans_alloc(sc->mp, &M_RES(sc->mp)->tr_itruncate, + resblks, 0, 0, &sc->tp); + + return xfs_trans_alloc_empty(sc->mp, &sc->tp); +} + +/* Set us up with a transaction and an empty context. */ +int +xchk_setup_fs( + struct xfs_scrub *sc) +{ + uint resblks; + + resblks = xrep_calc_ag_resblks(sc); + return xchk_trans_alloc(sc, resblks); +} + +/* Set us up with AG headers and btree cursors. */ +int +xchk_setup_ag_btree( + struct xfs_scrub *sc, + bool force_log) +{ + struct xfs_mount *mp = sc->mp; + int error; + + /* + * If the caller asks us to checkpont the log, do so. This + * expensive operation should be performed infrequently and only + * as a last resort. Any caller that sets force_log should + * document why they need to do so. + */ + if (force_log) { + error = xchk_checkpoint_log(mp); + if (error) + return error; + } + + error = xchk_setup_fs(sc); + if (error) + return error; + + return xchk_ag_init(sc, sc->sm->sm_agno, &sc->sa); +} + +/* Push everything out of the log onto disk. */ +int +xchk_checkpoint_log( + struct xfs_mount *mp) +{ + int error; + + error = xfs_log_force(mp, XFS_LOG_SYNC); + if (error) + return error; + xfs_ail_push_all_sync(mp->m_ail); + return 0; +} + +/* Verify that an inode is allocated ondisk, then return its cached inode. */ +int +xchk_iget( + struct xfs_scrub *sc, + xfs_ino_t inum, + struct xfs_inode **ipp) +{ + return xfs_iget(sc->mp, sc->tp, inum, XFS_IGET_UNTRUSTED, 0, ipp); +} + +/* + * Try to grab an inode in a manner that avoids races with physical inode + * allocation. If we can't, return the locked AGI buffer so that the caller + * can single-step the loading process to see where things went wrong. + * Callers must have a valid scrub transaction. + * + * If the iget succeeds, return 0, a NULL AGI, and the inode. + * + * If the iget fails, return the error, the locked AGI, and a NULL inode. This + * can include -EINVAL and -ENOENT for invalid inode numbers or inodes that are + * no longer allocated; or any other corruption or runtime error. + * + * If the AGI read fails, return the error, a NULL AGI, and NULL inode. + * + * If a fatal signal is pending, return -EINTR, a NULL AGI, and a NULL inode. + */ +int +xchk_iget_agi( + struct xfs_scrub *sc, + xfs_ino_t inum, + struct xfs_buf **agi_bpp, + struct xfs_inode **ipp) +{ + struct xfs_mount *mp = sc->mp; + struct xfs_trans *tp = sc->tp; + struct xfs_perag *pag; + int error; + + ASSERT(sc->tp != NULL); + +again: + *agi_bpp = NULL; + *ipp = NULL; + error = 0; + + if (xchk_should_terminate(sc, &error)) + return error; + + /* + * Attach the AGI buffer to the scrub transaction to avoid deadlocks + * in the iget cache miss path. + */ + pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, inum)); + error = xfs_ialloc_read_agi(pag, tp, agi_bpp); + xfs_perag_put(pag); + if (error) + return error; + + error = xfs_iget(mp, tp, inum, + XFS_IGET_NORETRY | XFS_IGET_UNTRUSTED, 0, ipp); + if (error == -EAGAIN) { + /* + * The inode may be in core but temporarily unavailable and may + * require the AGI buffer before it can be returned. Drop the + * AGI buffer and retry the lookup. + * + * Incore lookup will fail with EAGAIN on a cache hit if the + * inode is queued to the inactivation list. The inactivation + * worker may remove the inode from the unlinked list and hence + * needs the AGI. + * + * Hence xchk_iget_agi() needs to drop the AGI lock on EAGAIN + * to allow inodegc to make progress and move the inode to + * IRECLAIMABLE state where xfs_iget will be able to return it + * again if it can lock the inode. + */ + xfs_trans_brelse(tp, *agi_bpp); + delay(1); + goto again; + } + if (error) + return error; + + /* We got the inode, so we can release the AGI. */ + ASSERT(*ipp != NULL); + xfs_trans_brelse(tp, *agi_bpp); + *agi_bpp = NULL; + return 0; +} + +/* Install an inode that we opened by handle for scrubbing. */ +int +xchk_install_handle_inode( + struct xfs_scrub *sc, + struct xfs_inode *ip) +{ + if (VFS_I(ip)->i_generation != sc->sm->sm_gen) { + xchk_irele(sc, ip); + return -ENOENT; + } + + sc->ip = ip; + return 0; +} + +/* + * Install an already-referenced inode for scrubbing. Get our own reference to + * the inode to make disposal simpler. The inode must not be in I_FREEING or + * I_WILL_FREE state! + */ +int +xchk_install_live_inode( + struct xfs_scrub *sc, + struct xfs_inode *ip) +{ + if (!igrab(VFS_I(ip))) { + xchk_ino_set_corrupt(sc, ip->i_ino); + return -EFSCORRUPTED; + } + + sc->ip = ip; + return 0; +} + +/* + * In preparation to scrub metadata structures that hang off of an inode, + * grab either the inode referenced in the scrub control structure or the + * inode passed in. If the inumber does not reference an allocated inode + * record, the function returns ENOENT to end the scrub early. The inode + * is not locked. + */ +int +xchk_iget_for_scrubbing( + struct xfs_scrub *sc) +{ + struct xfs_imap imap; + struct xfs_mount *mp = sc->mp; + struct xfs_perag *pag; + struct xfs_buf *agi_bp; + struct xfs_inode *ip_in = XFS_I(file_inode(sc->file)); + struct xfs_inode *ip = NULL; + xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, sc->sm->sm_ino); + int error; + + ASSERT(sc->tp == NULL); + + /* We want to scan the inode we already had opened. */ + if (sc->sm->sm_ino == 0 || sc->sm->sm_ino == ip_in->i_ino) + return xchk_install_live_inode(sc, ip_in); + + /* Reject internal metadata files and obviously bad inode numbers. */ + if (xfs_internal_inum(mp, sc->sm->sm_ino)) + return -ENOENT; + if (!xfs_verify_ino(sc->mp, sc->sm->sm_ino)) + return -ENOENT; + + /* Try a regular untrusted iget. */ + error = xchk_iget(sc, sc->sm->sm_ino, &ip); + if (!error) + return xchk_install_handle_inode(sc, ip); + if (error == -ENOENT) + return error; + if (error != -EINVAL) + goto out_error; + + /* + * EINVAL with IGET_UNTRUSTED probably means one of several things: + * userspace gave us an inode number that doesn't correspond to fs + * space; the inode btree lacks a record for this inode; or there is a + * record, and it says this inode is free. + * + * We want to look up this inode in the inobt to distinguish two + * scenarios: (1) the inobt says the inode is free, in which case + * there's nothing to do; and (2) the inobt says the inode is + * allocated, but loading it failed due to corruption. + * + * Allocate a transaction and grab the AGI to prevent inobt activity + * in this AG. Retry the iget in case someone allocated a new inode + * after the first iget failed. + */ + error = xchk_trans_alloc(sc, 0); + if (error) + goto out_error; + + error = xchk_iget_agi(sc, sc->sm->sm_ino, &agi_bp, &ip); + if (error == 0) { + /* Actually got the inode, so install it. */ + xchk_trans_cancel(sc); + return xchk_install_handle_inode(sc, ip); + } + if (error == -ENOENT) + goto out_gone; + if (error != -EINVAL) + goto out_cancel; + + /* Ensure that we have protected against inode allocation/freeing. */ + if (agi_bp == NULL) { + ASSERT(agi_bp != NULL); + error = -ECANCELED; + goto out_cancel; + } + + /* + * Untrusted iget failed a second time. Let's try an inobt lookup. + * If the inobt thinks this the inode neither can exist inside the + * filesystem nor is allocated, return ENOENT to signal that the check + * can be skipped. + * + * If the lookup returns corruption, we'll mark this inode corrupt and + * exit to userspace. There's little chance of fixing anything until + * the inobt is straightened out, but there's nothing we can do here. + * + * If the lookup encounters any other error, exit to userspace. + * + * If the lookup succeeds, something else must be very wrong in the fs + * such that setting up the incore inode failed in some strange way. + * Treat those as corruptions. + */ + pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, sc->sm->sm_ino)); + if (!pag) { + error = -EFSCORRUPTED; + goto out_cancel; + } + + error = xfs_imap(pag, sc->tp, sc->sm->sm_ino, &imap, + XFS_IGET_UNTRUSTED); + xfs_perag_put(pag); + if (error == -EINVAL || error == -ENOENT) + goto out_gone; + if (!error) + error = -EFSCORRUPTED; + +out_cancel: + xchk_trans_cancel(sc); +out_error: + trace_xchk_op_error(sc, agno, XFS_INO_TO_AGBNO(mp, sc->sm->sm_ino), + error, __return_address); + return error; +out_gone: + /* The file is gone, so there's nothing to check. */ + xchk_trans_cancel(sc); + return -ENOENT; +} + +/* Release an inode, possibly dropping it in the process. */ +void +xchk_irele( + struct xfs_scrub *sc, + struct xfs_inode *ip) +{ + if (current->journal_info != NULL) { + ASSERT(current->journal_info == sc->tp); + + /* + * If we are in a transaction, we /cannot/ drop the inode + * ourselves, because the VFS will trigger writeback, which + * can require a transaction. Clear DONTCACHE to force the + * inode to the LRU, where someone else can take care of + * dropping it. + * + * Note that when we grabbed our reference to the inode, it + * could have had an active ref and DONTCACHE set if a sysadmin + * is trying to coerce a change in file access mode. icache + * hits do not clear DONTCACHE, so we must do it here. + */ + spin_lock(&VFS_I(ip)->i_lock); + VFS_I(ip)->i_state &= ~I_DONTCACHE; + spin_unlock(&VFS_I(ip)->i_lock); + } else if (atomic_read(&VFS_I(ip)->i_count) == 1) { + /* + * If this is the last reference to the inode and the caller + * permits it, set DONTCACHE to avoid thrashing. + */ + d_mark_dontcache(VFS_I(ip)); + } + + xfs_irele(ip); +} + +/* + * Set us up to scrub metadata mapped by a file's fork. Callers must not use + * this to operate on user-accessible regular file data because the MMAPLOCK is + * not taken. + */ +int +xchk_setup_inode_contents( + struct xfs_scrub *sc, + unsigned int resblks) +{ + int error; + + error = xchk_iget_for_scrubbing(sc); + if (error) + return error; + + /* Lock the inode so the VFS cannot touch this file. */ + xchk_ilock(sc, XFS_IOLOCK_EXCL); + + error = xchk_trans_alloc(sc, resblks); + if (error) + goto out; + xchk_ilock(sc, XFS_ILOCK_EXCL); +out: + /* scrub teardown will unlock and release the inode for us */ + return error; +} + +void +xchk_ilock( + struct xfs_scrub *sc, + unsigned int ilock_flags) +{ + xfs_ilock(sc->ip, ilock_flags); + sc->ilock_flags |= ilock_flags; +} + +bool +xchk_ilock_nowait( + struct xfs_scrub *sc, + unsigned int ilock_flags) +{ + if (xfs_ilock_nowait(sc->ip, ilock_flags)) { + sc->ilock_flags |= ilock_flags; + return true; + } + + return false; +} + +void +xchk_iunlock( + struct xfs_scrub *sc, + unsigned int ilock_flags) +{ + sc->ilock_flags &= ~ilock_flags; + xfs_iunlock(sc->ip, ilock_flags); +} + +/* + * Predicate that decides if we need to evaluate the cross-reference check. + * If there was an error accessing the cross-reference btree, just delete + * the cursor and skip the check. + */ +bool +xchk_should_check_xref( + struct xfs_scrub *sc, + int *error, + struct xfs_btree_cur **curpp) +{ + /* No point in xref if we already know we're corrupt. */ + if (xchk_skip_xref(sc->sm)) + return false; + + if (*error == 0) + return true; + + if (curpp) { + /* If we've already given up on xref, just bail out. */ + if (!*curpp) + return false; + + /* xref error, delete cursor and bail out. */ + xfs_btree_del_cursor(*curpp, XFS_BTREE_ERROR); + *curpp = NULL; + } + + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XFAIL; + trace_xchk_xref_error(sc, *error, __return_address); + + /* + * Errors encountered during cross-referencing with another + * data structure should not cause this scrubber to abort. + */ + *error = 0; + return false; +} + +/* Run the structure verifiers on in-memory buffers to detect bad memory. */ +void +xchk_buffer_recheck( + struct xfs_scrub *sc, + struct xfs_buf *bp) +{ + xfs_failaddr_t fa; + + if (bp->b_ops == NULL) { + xchk_block_set_corrupt(sc, bp); + return; + } + if (bp->b_ops->verify_struct == NULL) { + xchk_set_incomplete(sc); + return; + } + fa = bp->b_ops->verify_struct(bp); + if (!fa) + return; + sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT; + trace_xchk_block_error(sc, xfs_buf_daddr(bp), fa); +} + +static inline int +xchk_metadata_inode_subtype( + struct xfs_scrub *sc, + unsigned int scrub_type) +{ + __u32 smtype = sc->sm->sm_type; + int error; + + sc->sm->sm_type = scrub_type; + + switch (scrub_type) { + case XFS_SCRUB_TYPE_INODE: + error = xchk_inode(sc); + break; + case XFS_SCRUB_TYPE_BMBTD: + error = xchk_bmap_data(sc); + break; + default: + ASSERT(0); + error = -EFSCORRUPTED; + break; + } + + sc->sm->sm_type = smtype; + return error; +} + +/* + * Scrub the attr/data forks of a metadata inode. The metadata inode must be + * pointed to by sc->ip and the ILOCK must be held. + */ +int +xchk_metadata_inode_forks( + struct xfs_scrub *sc) +{ + bool shared; + int error; + + if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) + return 0; + + /* Check the inode record. */ + error = xchk_metadata_inode_subtype(sc, XFS_SCRUB_TYPE_INODE); + if (error || (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)) + return error; + + /* Metadata inodes don't live on the rt device. */ + if (sc->ip->i_diflags & XFS_DIFLAG_REALTIME) { + xchk_ino_set_corrupt(sc, sc->ip->i_ino); + return 0; + } + + /* They should never participate in reflink. */ + if (xfs_is_reflink_inode(sc->ip)) { + xchk_ino_set_corrupt(sc, sc->ip->i_ino); + return 0; + } + + /* They also should never have extended attributes. */ + if (xfs_inode_hasattr(sc->ip)) { + xchk_ino_set_corrupt(sc, sc->ip->i_ino); + return 0; + } + + /* Invoke the data fork scrubber. */ + error = xchk_metadata_inode_subtype(sc, XFS_SCRUB_TYPE_BMBTD); + if (error || (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)) + return error; + + /* Look for incorrect shared blocks. */ + if (xfs_has_reflink(sc->mp)) { + error = xfs_reflink_inode_has_shared_extents(sc->tp, sc->ip, + &shared); + if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0, + &error)) + return error; + if (shared) + xchk_ino_set_corrupt(sc, sc->ip->i_ino); + } + + return 0; +} + +/* + * Enable filesystem hooks (i.e. runtime code patching) before starting a scrub + * operation. Callers must not hold any locks that intersect with the CPU + * hotplug lock (e.g. writeback locks) because code patching must halt the CPUs + * to change kernel code. + */ +void +xchk_fsgates_enable( + struct xfs_scrub *sc, + unsigned int scrub_fsgates) +{ + ASSERT(!(scrub_fsgates & ~XCHK_FSGATES_ALL)); + ASSERT(!(sc->flags & scrub_fsgates)); + + trace_xchk_fsgates_enable(sc, scrub_fsgates); + + if (scrub_fsgates & XCHK_FSGATES_DRAIN) + xfs_drain_wait_enable(); + + sc->flags |= scrub_fsgates; +} + +/* + * Decide if this is this a cached inode that's also allocated. The caller + * must hold a reference to an AG and the AGI buffer lock to prevent inodes + * from being allocated or freed. + * + * Look up an inode by number in the given file system. If the inode number + * is invalid, return -EINVAL. If the inode is not in cache, return -ENODATA. + * If the inode is being reclaimed, return -ENODATA because we know the inode + * cache cannot be updating the ondisk metadata. + * + * Otherwise, the incore inode is the one we want, and it is either live, + * somewhere in the inactivation machinery, or reclaimable. The inode is + * allocated if i_mode is nonzero. In all three cases, the cached inode will + * be more up to date than the ondisk inode buffer, so we must use the incore + * i_mode. + */ +int +xchk_inode_is_allocated( + struct xfs_scrub *sc, + xfs_agino_t agino, + bool *inuse) +{ + struct xfs_mount *mp = sc->mp; + struct xfs_perag *pag = sc->sa.pag; + xfs_ino_t ino; + struct xfs_inode *ip; + int error; + + /* caller must hold perag reference */ + if (pag == NULL) { + ASSERT(pag != NULL); + return -EINVAL; + } + + /* caller must have AGI buffer */ + if (sc->sa.agi_bp == NULL) { + ASSERT(sc->sa.agi_bp != NULL); + return -EINVAL; + } + + /* reject inode numbers outside existing AGs */ + ino = XFS_AGINO_TO_INO(sc->mp, pag->pag_agno, agino); + if (!xfs_verify_ino(mp, ino)) + return -EINVAL; + + error = -ENODATA; + rcu_read_lock(); + ip = radix_tree_lookup(&pag->pag_ici_root, agino); + if (!ip) { + /* cache miss */ + goto out_rcu; + } + + /* + * If the inode number doesn't match, the incore inode got reused + * during an RCU grace period and the radix tree hasn't been updated. + * This isn't the inode we want. + */ + spin_lock(&ip->i_flags_lock); + if (ip->i_ino != ino) + goto out_skip; + + trace_xchk_inode_is_allocated(ip); + + /* + * We have an incore inode that matches the inode we want, and the + * caller holds the perag structure and the AGI buffer. Let's check + * our assumptions below: + */ + +#ifdef DEBUG + /* + * (1) If the incore inode is live (i.e. referenced from the dcache), + * it will not be INEW, nor will it be in the inactivation or reclaim + * machinery. The ondisk inode had better be allocated. This is the + * most trivial case. + */ + if (!(ip->i_flags & (XFS_NEED_INACTIVE | XFS_INEW | XFS_IRECLAIMABLE | + XFS_INACTIVATING))) { + /* live inode */ + ASSERT(VFS_I(ip)->i_mode != 0); + } + + /* + * If the incore inode is INEW, there are several possibilities: + * + * (2) For a file that is being created, note that we allocate the + * ondisk inode before allocating, initializing, and adding the incore + * inode to the radix tree. + * + * (3) If the incore inode is being recycled, the inode has to be + * allocated because we don't allow freed inodes to be recycled. + * Recycling doesn't touch i_mode. + */ + if (ip->i_flags & XFS_INEW) { + /* created on disk already or recycling */ + ASSERT(VFS_I(ip)->i_mode != 0); + } + + /* + * (4) If the inode is queued for inactivation (NEED_INACTIVE) but + * inactivation has not started (!INACTIVATING), it is still allocated. + */ + if ((ip->i_flags & XFS_NEED_INACTIVE) && + !(ip->i_flags & XFS_INACTIVATING)) { + /* definitely before difree */ + ASSERT(VFS_I(ip)->i_mode != 0); + } +#endif + + /* + * If the incore inode is undergoing inactivation (INACTIVATING), there + * are two possibilities: + * + * (5) It is before the point where it would get freed ondisk, in which + * case i_mode is still nonzero. + * + * (6) It has already been freed, in which case i_mode is zero. + * + * We don't take the ILOCK here, but difree and dialloc update the AGI, + * and we've taken the AGI buffer lock, which prevents that from + * happening. + */ + + /* + * (7) Inodes undergoing inactivation (INACTIVATING) or queued for + * reclaim (IRECLAIMABLE) could be allocated or free. i_mode still + * reflects the ondisk state. + */ + + /* + * (8) If the inode is in IFLUSHING, it's safe to query i_mode because + * the flush code uses i_mode to format the ondisk inode. + */ + + /* + * (9) If the inode is in IRECLAIM and was reachable via the radix + * tree, it still has the same i_mode as it did before it entered + * reclaim. The inode object is still alive because we hold the RCU + * read lock. + */ + + *inuse = VFS_I(ip)->i_mode != 0; + error = 0; + +out_skip: + spin_unlock(&ip->i_flags_lock); +out_rcu: + rcu_read_unlock(); + return error; +} |