| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Darrick J. Wong | 1686 | 79.34% | 55 | 77.46% |
| Eric Sandeen | 396 | 18.64% | 3 | 4.23% |
| David Chinner | 22 | 1.04% | 9 | 12.68% |
| Russell Cattelan | 8 | 0.38% | 1 | 1.41% |
| Michal Marek | 8 | 0.38% | 1 | 1.41% |
| Christoph Hellwig | 5 | 0.24% | 2 | 2.82% |
| Total | 2125 | 71 |
// 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_log_format.h" #include "xfs_trans.h" #include "xfs_inode.h" #include "xfs_quota.h" #include "xfs_qm.h" #include "xfs_errortag.h" #include "xfs_error.h" #include "xfs_scrub.h" #include "scrub/scrub.h" #include "scrub/common.h" #include "scrub/trace.h" #include "scrub/repair.h" #include "scrub/health.h" #include "scrub/stats.h" #include "scrub/xfile.h" /* * Online Scrub and Repair * * Traditionally, XFS (the kernel driver) did not know how to check or * repair on-disk data structures. That task was left to the xfs_check * and xfs_repair tools, both of which require taking the filesystem * offline for a thorough but time consuming examination. Online * scrub & repair, on the other hand, enables us to check the metadata * for obvious errors while carefully stepping around the filesystem's * ongoing operations, locking rules, etc. * * Given that most XFS metadata consist of records stored in a btree, * most of the checking functions iterate the btree blocks themselves * looking for irregularities. When a record block is encountered, each * record can be checked for obviously bad values. Record values can * also be cross-referenced against other btrees to look for potential * misunderstandings between pieces of metadata. * * It is expected that the checkers responsible for per-AG metadata * structures will lock the AG headers (AGI, AGF, AGFL), iterate the * metadata structure, and perform any relevant cross-referencing before * unlocking the AG and returning the results to userspace. These * scrubbers must not keep an AG locked for too long to avoid tying up * the block and inode allocators. * * Block maps and b-trees rooted in an inode present a special challenge * because they can involve extents from any AG. The general scrubber * structure of lock -> check -> xref -> unlock still holds, but AG * locking order rules /must/ be obeyed to avoid deadlocks. The * ordering rule, of course, is that we must lock in increasing AG * order. Helper functions are provided to track which AG headers we've * already locked. If we detect an imminent locking order violation, we * can signal a potential deadlock, in which case the scrubber can jump * out to the top level, lock all the AGs in order, and retry the scrub. * * For file data (directories, extended attributes, symlinks) scrub, we * can simply lock the inode and walk the data. For btree data * (directories and attributes) we follow the same btree-scrubbing * strategy outlined previously to check the records. * * We use a bit of trickery with transactions to avoid buffer deadlocks * if there is a cycle in the metadata. The basic problem is that * travelling down a btree involves locking the current buffer at each * tree level. If a pointer should somehow point back to a buffer that * we've already examined, we will deadlock due to the second buffer * locking attempt. Note however that grabbing a buffer in transaction * context links the locked buffer to the transaction. If we try to * re-grab the buffer in the context of the same transaction, we avoid * the second lock attempt and continue. Between the verifier and the * scrubber, something will notice that something is amiss and report * the corruption. Therefore, each scrubber will allocate an empty * transaction, attach buffers to it, and cancel the transaction at the * end of the scrub run. Cancelling a non-dirty transaction simply * unlocks the buffers. * * There are four pieces of data that scrub can communicate to * userspace. The first is the error code (errno), which can be used to * communicate operational errors in performing the scrub. There are * also three flags that can be set in the scrub context. If the data * structure itself is corrupt, the CORRUPT flag will be set. If * the metadata is correct but otherwise suboptimal, the PREEN flag * will be set. * * We perform secondary validation of filesystem metadata by * cross-referencing every record with all other available metadata. * For example, for block mapping extents, we verify that there are no * records in the free space and inode btrees corresponding to that * space extent and that there is a corresponding entry in the reverse * mapping btree. Inconsistent metadata is noted by setting the * XCORRUPT flag; btree query function errors are noted by setting the * XFAIL flag and deleting the cursor to prevent further attempts to * cross-reference with a defective btree. * * If a piece of metadata proves corrupt or suboptimal, the userspace * program can ask the kernel to apply some tender loving care (TLC) to * the metadata object by setting the REPAIR flag and re-calling the * scrub ioctl. "Corruption" is defined by metadata violating the * on-disk specification; operations cannot continue if the violation is * left untreated. It is possible for XFS to continue if an object is * "suboptimal", however performance may be degraded. Repairs are * usually performed by rebuilding the metadata entirely out of * redundant metadata. Optimizing, on the other hand, can sometimes be * done without rebuilding entire structures. * * Generally speaking, the repair code has the following code structure: * Lock -> scrub -> repair -> commit -> re-lock -> re-scrub -> unlock. * The first check helps us figure out if we need to rebuild or simply * optimize the structure so that the rebuild knows what to do. The * second check evaluates the completeness of the repair; that is what * is reported to userspace. * * A quick note on symbol prefixes: * - "xfs_" are general XFS symbols. * - "xchk_" are symbols related to metadata checking. * - "xrep_" are symbols related to metadata repair. * - "xfs_scrub_" are symbols that tie online fsck to the rest of XFS. */ /* * Scrub probe -- userspace uses this to probe if we're willing to scrub * or repair a given mountpoint. This will be used by xfs_scrub to * probe the kernel's abilities to scrub (and repair) the metadata. We * do this by validating the ioctl inputs from userspace, preparing the * filesystem for a scrub (or a repair) operation, and immediately * returning to userspace. Userspace can use the returned errno and * structure state to decide (in broad terms) if scrub/repair are * supported by the running kernel. */ static int xchk_probe( struct xfs_scrub *sc) { int error = 0; if (xchk_should_terminate(sc, &error)) return error; return 0; } /* Scrub setup and teardown */ static inline void xchk_fsgates_disable( struct xfs_scrub *sc) { if (!(sc->flags & XCHK_FSGATES_ALL)) return; trace_xchk_fsgates_disable(sc, sc->flags & XCHK_FSGATES_ALL); if (sc->flags & XCHK_FSGATES_DRAIN) xfs_drain_wait_disable(); sc->flags &= ~XCHK_FSGATES_ALL; } /* Free all the resources and finish the transactions. */ STATIC int xchk_teardown( struct xfs_scrub *sc, int error) { xchk_ag_free(sc, &sc->sa); if (sc->tp) { if (error == 0 && (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)) error = xfs_trans_commit(sc->tp); else xfs_trans_cancel(sc->tp); sc->tp = NULL; } if (sc->ip) { if (sc->ilock_flags) xchk_iunlock(sc, sc->ilock_flags); xchk_irele(sc, sc->ip); sc->ip = NULL; } if (sc->flags & XCHK_HAVE_FREEZE_PROT) { sc->flags &= ~XCHK_HAVE_FREEZE_PROT; mnt_drop_write_file(sc->file); } if (sc->xfile) { xfile_destroy(sc->xfile); sc->xfile = NULL; } if (sc->buf) { if (sc->buf_cleanup) sc->buf_cleanup(sc->buf); kvfree(sc->buf); sc->buf_cleanup = NULL; sc->buf = NULL; } xchk_fsgates_disable(sc); return error; } /* Scrubbing dispatch. */ static const struct xchk_meta_ops meta_scrub_ops[] = { [XFS_SCRUB_TYPE_PROBE] = { /* ioctl presence test */ .type = ST_NONE, .setup = xchk_setup_fs, .scrub = xchk_probe, .repair = xrep_probe, }, [XFS_SCRUB_TYPE_SB] = { /* superblock */ .type = ST_PERAG, .setup = xchk_setup_agheader, .scrub = xchk_superblock, .repair = xrep_superblock, }, [XFS_SCRUB_TYPE_AGF] = { /* agf */ .type = ST_PERAG, .setup = xchk_setup_agheader, .scrub = xchk_agf, .repair = xrep_agf, }, [XFS_SCRUB_TYPE_AGFL]= { /* agfl */ .type = ST_PERAG, .setup = xchk_setup_agheader, .scrub = xchk_agfl, .repair = xrep_agfl, }, [XFS_SCRUB_TYPE_AGI] = { /* agi */ .type = ST_PERAG, .setup = xchk_setup_agheader, .scrub = xchk_agi, .repair = xrep_agi, }, [XFS_SCRUB_TYPE_BNOBT] = { /* bnobt */ .type = ST_PERAG, .setup = xchk_setup_ag_allocbt, .scrub = xchk_bnobt, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_CNTBT] = { /* cntbt */ .type = ST_PERAG, .setup = xchk_setup_ag_allocbt, .scrub = xchk_cntbt, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_INOBT] = { /* inobt */ .type = ST_PERAG, .setup = xchk_setup_ag_iallocbt, .scrub = xchk_inobt, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_FINOBT] = { /* finobt */ .type = ST_PERAG, .setup = xchk_setup_ag_iallocbt, .scrub = xchk_finobt, .has = xfs_has_finobt, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_RMAPBT] = { /* rmapbt */ .type = ST_PERAG, .setup = xchk_setup_ag_rmapbt, .scrub = xchk_rmapbt, .has = xfs_has_rmapbt, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_REFCNTBT] = { /* refcountbt */ .type = ST_PERAG, .setup = xchk_setup_ag_refcountbt, .scrub = xchk_refcountbt, .has = xfs_has_reflink, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_INODE] = { /* inode record */ .type = ST_INODE, .setup = xchk_setup_inode, .scrub = xchk_inode, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_BMBTD] = { /* inode data fork */ .type = ST_INODE, .setup = xchk_setup_inode_bmap, .scrub = xchk_bmap_data, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_BMBTA] = { /* inode attr fork */ .type = ST_INODE, .setup = xchk_setup_inode_bmap, .scrub = xchk_bmap_attr, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_BMBTC] = { /* inode CoW fork */ .type = ST_INODE, .setup = xchk_setup_inode_bmap, .scrub = xchk_bmap_cow, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_DIR] = { /* directory */ .type = ST_INODE, .setup = xchk_setup_directory, .scrub = xchk_directory, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_XATTR] = { /* extended attributes */ .type = ST_INODE, .setup = xchk_setup_xattr, .scrub = xchk_xattr, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_SYMLINK] = { /* symbolic link */ .type = ST_INODE, .setup = xchk_setup_symlink, .scrub = xchk_symlink, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_PARENT] = { /* parent pointers */ .type = ST_INODE, .setup = xchk_setup_parent, .scrub = xchk_parent, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_RTBITMAP] = { /* realtime bitmap */ .type = ST_FS, .setup = xchk_setup_rtbitmap, .scrub = xchk_rtbitmap, .has = xfs_has_realtime, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_RTSUM] = { /* realtime summary */ .type = ST_FS, .setup = xchk_setup_rtsummary, .scrub = xchk_rtsummary, .has = xfs_has_realtime, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_UQUOTA] = { /* user quota */ .type = ST_FS, .setup = xchk_setup_quota, .scrub = xchk_quota, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_GQUOTA] = { /* group quota */ .type = ST_FS, .setup = xchk_setup_quota, .scrub = xchk_quota, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_PQUOTA] = { /* project quota */ .type = ST_FS, .setup = xchk_setup_quota, .scrub = xchk_quota, .repair = xrep_notsupported, }, [XFS_SCRUB_TYPE_FSCOUNTERS] = { /* fs summary counters */ .type = ST_FS, .setup = xchk_setup_fscounters, .scrub = xchk_fscounters, .repair = xrep_notsupported, }, }; static int xchk_validate_inputs( struct xfs_mount *mp, struct xfs_scrub_metadata *sm) { int error; const struct xchk_meta_ops *ops; error = -EINVAL; /* Check our inputs. */ sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT; if (sm->sm_flags & ~XFS_SCRUB_FLAGS_IN) goto out; /* sm_reserved[] must be zero */ if (memchr_inv(sm->sm_reserved, 0, sizeof(sm->sm_reserved))) goto out; error = -ENOENT; /* Do we know about this type of metadata? */ if (sm->sm_type >= XFS_SCRUB_TYPE_NR) goto out; ops = &meta_scrub_ops[sm->sm_type]; if (ops->setup == NULL || ops->scrub == NULL) goto out; /* Does this fs even support this type of metadata? */ if (ops->has && !ops->has(mp)) goto out; error = -EINVAL; /* restricting fields must be appropriate for type */ switch (ops->type) { case ST_NONE: case ST_FS: if (sm->sm_ino || sm->sm_gen || sm->sm_agno) goto out; break; case ST_PERAG: if (sm->sm_ino || sm->sm_gen || sm->sm_agno >= mp->m_sb.sb_agcount) goto out; break; case ST_INODE: if (sm->sm_agno || (sm->sm_gen && !sm->sm_ino)) goto out; break; default: goto out; } /* No rebuild without repair. */ if ((sm->sm_flags & XFS_SCRUB_IFLAG_FORCE_REBUILD) && !(sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)) return -EINVAL; /* * We only want to repair read-write v5+ filesystems. Defer the check * for ops->repair until after our scrub confirms that we need to * perform repairs so that we avoid failing due to not supporting * repairing an object that doesn't need repairs. */ if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) { error = -EOPNOTSUPP; if (!xfs_has_crc(mp)) goto out; error = -EROFS; if (xfs_is_readonly(mp)) goto out; } error = 0; out: return error; } #ifdef CONFIG_XFS_ONLINE_REPAIR static inline void xchk_postmortem(struct xfs_scrub *sc) { /* * Userspace asked us to repair something, we repaired it, rescanned * it, and the rescan says it's still broken. Scream about this in * the system logs. */ if ((sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) && (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT | XFS_SCRUB_OFLAG_XCORRUPT))) xrep_failure(sc->mp); } #else static inline void xchk_postmortem(struct xfs_scrub *sc) { /* * Userspace asked us to scrub something, it's broken, and we have no * way of fixing it. Scream in the logs. */ if (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT | XFS_SCRUB_OFLAG_XCORRUPT)) xfs_alert_ratelimited(sc->mp, "Corruption detected during scrub."); } #endif /* CONFIG_XFS_ONLINE_REPAIR */ /* Dispatch metadata scrubbing. */ int xfs_scrub_metadata( struct file *file, struct xfs_scrub_metadata *sm) { struct xchk_stats_run run = { }; struct xfs_scrub *sc; struct xfs_mount *mp = XFS_I(file_inode(file))->i_mount; u64 check_start; int error = 0; BUILD_BUG_ON(sizeof(meta_scrub_ops) != (sizeof(struct xchk_meta_ops) * XFS_SCRUB_TYPE_NR)); trace_xchk_start(XFS_I(file_inode(file)), sm, error); /* Forbidden if we are shut down or mounted norecovery. */ error = -ESHUTDOWN; if (xfs_is_shutdown(mp)) goto out; error = -ENOTRECOVERABLE; if (xfs_has_norecovery(mp)) goto out; error = xchk_validate_inputs(mp, sm); if (error) goto out; xfs_warn_mount(mp, XFS_OPSTATE_WARNED_SCRUB, "EXPERIMENTAL online scrub feature in use. Use at your own risk!"); sc = kzalloc(sizeof(struct xfs_scrub), XCHK_GFP_FLAGS); if (!sc) { error = -ENOMEM; goto out; } sc->mp = mp; sc->file = file; sc->sm = sm; sc->ops = &meta_scrub_ops[sm->sm_type]; sc->sick_mask = xchk_health_mask_for_scrub_type(sm->sm_type); retry_op: /* * When repairs are allowed, prevent freezing or readonly remount while * scrub is running with a real transaction. */ if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) { error = mnt_want_write_file(sc->file); if (error) goto out_sc; sc->flags |= XCHK_HAVE_FREEZE_PROT; } /* Set up for the operation. */ error = sc->ops->setup(sc); if (error == -EDEADLOCK && !(sc->flags & XCHK_TRY_HARDER)) goto try_harder; if (error == -ECHRNG && !(sc->flags & XCHK_NEED_DRAIN)) goto need_drain; if (error) goto out_teardown; /* Scrub for errors. */ check_start = xchk_stats_now(); error = sc->ops->scrub(sc); run.scrub_ns += xchk_stats_elapsed_ns(check_start); if (error == -EDEADLOCK && !(sc->flags & XCHK_TRY_HARDER)) goto try_harder; if (error == -ECHRNG && !(sc->flags & XCHK_NEED_DRAIN)) goto need_drain; if (error || (sm->sm_flags & XFS_SCRUB_OFLAG_INCOMPLETE)) goto out_teardown; xchk_update_health(sc); if ((sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) && !(sc->flags & XREP_ALREADY_FIXED)) { bool needs_fix = xchk_needs_repair(sc->sm); /* Userspace asked us to rebuild the structure regardless. */ if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_FORCE_REBUILD) needs_fix = true; /* Let debug users force us into the repair routines. */ if (XFS_TEST_ERROR(needs_fix, mp, XFS_ERRTAG_FORCE_SCRUB_REPAIR)) needs_fix = true; /* * If userspace asked for a repair but it wasn't necessary, * report that back to userspace. */ if (!needs_fix) { sc->sm->sm_flags |= XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED; goto out_nofix; } /* * If it's broken, userspace wants us to fix it, and we haven't * already tried to fix it, then attempt a repair. */ error = xrep_attempt(sc, &run); if (error == -EAGAIN) { /* * Either the repair function succeeded or it couldn't * get all the resources it needs; either way, we go * back to the beginning and call the scrub function. */ error = xchk_teardown(sc, 0); if (error) { xrep_failure(mp); goto out_sc; } goto retry_op; } } out_nofix: xchk_postmortem(sc); out_teardown: error = xchk_teardown(sc, error); out_sc: if (error != -ENOENT) xchk_stats_merge(mp, sm, &run); kfree(sc); out: trace_xchk_done(XFS_I(file_inode(file)), sm, error); if (error == -EFSCORRUPTED || error == -EFSBADCRC) { sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT; error = 0; } return error; need_drain: error = xchk_teardown(sc, 0); if (error) goto out_sc; sc->flags |= XCHK_NEED_DRAIN; run.retries++; goto retry_op; try_harder: /* * Scrubbers return -EDEADLOCK to mean 'try harder'. Tear down * everything we hold, then set up again with preparation for * worst-case scenarios. */ error = xchk_teardown(sc, 0); if (error) goto out_sc; sc->flags |= XCHK_TRY_HARDER; run.retries++; goto retry_op; }
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