diff options
Diffstat (limited to 'fs/xfs/scrub/dirtree_repair.c')
| -rw-r--r-- | fs/xfs/scrub/dirtree_repair.c | 821 |
1 files changed, 821 insertions, 0 deletions
diff --git a/fs/xfs/scrub/dirtree_repair.c b/fs/xfs/scrub/dirtree_repair.c new file mode 100644 index 0000000000..5c04e70ba9 --- /dev/null +++ b/fs/xfs/scrub/dirtree_repair.c @@ -0,0 +1,821 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2023-2024 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_trans_space.h" +#include "xfs_mount.h" +#include "xfs_log_format.h" +#include "xfs_trans.h" +#include "xfs_inode.h" +#include "xfs_icache.h" +#include "xfs_dir2.h" +#include "xfs_dir2_priv.h" +#include "xfs_attr.h" +#include "xfs_parent.h" +#include "scrub/scrub.h" +#include "scrub/common.h" +#include "scrub/bitmap.h" +#include "scrub/ino_bitmap.h" +#include "scrub/xfile.h" +#include "scrub/xfarray.h" +#include "scrub/xfblob.h" +#include "scrub/listxattr.h" +#include "scrub/trace.h" +#include "scrub/repair.h" +#include "scrub/orphanage.h" +#include "scrub/dirtree.h" +#include "scrub/readdir.h" + +/* + * Directory Tree Structure Repairs + * ================================ + * + * If we decide that the directory being scanned is participating in a + * directory loop, the only change we can make is to remove directory entries + * pointing down to @sc->ip. If that leaves it with no parents, the directory + * should be adopted by the orphanage. + */ + +/* Set up to repair directory loops. */ +int +xrep_setup_dirtree( + struct xfs_scrub *sc) +{ + return xrep_orphanage_try_create(sc); +} + +/* Change the outcome of this path. */ +static inline void +xrep_dirpath_set_outcome( + struct xchk_dirtree *dl, + struct xchk_dirpath *path, + enum xchk_dirpath_outcome outcome) +{ + trace_xrep_dirpath_set_outcome(dl->sc, path->path_nr, path->nr_steps, + outcome); + + path->outcome = outcome; +} + +/* Delete all paths. */ +STATIC void +xrep_dirtree_delete_all_paths( + struct xchk_dirtree *dl, + struct xchk_dirtree_outcomes *oc) +{ + struct xchk_dirpath *path; + + xchk_dirtree_for_each_path(dl, path) { + switch (path->outcome) { + case XCHK_DIRPATH_CORRUPT: + case XCHK_DIRPATH_LOOP: + oc->suspect--; + oc->bad++; + xrep_dirpath_set_outcome(dl, path, XCHK_DIRPATH_DELETE); + break; + case XCHK_DIRPATH_OK: + oc->good--; + oc->bad++; + xrep_dirpath_set_outcome(dl, path, XCHK_DIRPATH_DELETE); + break; + default: + break; + } + } + + ASSERT(oc->suspect == 0); + ASSERT(oc->good == 0); +} + +/* Since this is the surviving path, set the dotdot entry to this value. */ +STATIC void +xrep_dirpath_retain_parent( + struct xchk_dirtree *dl, + struct xchk_dirpath *path) +{ + struct xchk_dirpath_step step; + int error; + + error = xfarray_load(dl->path_steps, path->first_step, &step); + if (error) + return; + + dl->parent_ino = be64_to_cpu(step.pptr_rec.p_ino); +} + +/* Find the one surviving path so we know how to set dotdot. */ +STATIC void +xrep_dirtree_find_surviving_path( + struct xchk_dirtree *dl, + struct xchk_dirtree_outcomes *oc) +{ + struct xchk_dirpath *path; + bool foundit = false; + + xchk_dirtree_for_each_path(dl, path) { + switch (path->outcome) { + case XCHK_DIRPATH_CORRUPT: + case XCHK_DIRPATH_LOOP: + case XCHK_DIRPATH_OK: + if (!foundit) { + xrep_dirpath_retain_parent(dl, path); + foundit = true; + continue; + } + ASSERT(foundit == false); + break; + default: + break; + } + } + + ASSERT(oc->suspect + oc->good == 1); +} + +/* Delete all paths except for the one good one. */ +STATIC void +xrep_dirtree_keep_one_good_path( + struct xchk_dirtree *dl, + struct xchk_dirtree_outcomes *oc) +{ + struct xchk_dirpath *path; + bool foundit = false; + + xchk_dirtree_for_each_path(dl, path) { + switch (path->outcome) { + case XCHK_DIRPATH_CORRUPT: + case XCHK_DIRPATH_LOOP: + oc->suspect--; + oc->bad++; + xrep_dirpath_set_outcome(dl, path, XCHK_DIRPATH_DELETE); + break; + case XCHK_DIRPATH_OK: + if (!foundit) { + xrep_dirpath_retain_parent(dl, path); + foundit = true; + continue; + } + oc->good--; + oc->bad++; + xrep_dirpath_set_outcome(dl, path, XCHK_DIRPATH_DELETE); + break; + default: + break; + } + } + + ASSERT(oc->suspect == 0); + ASSERT(oc->good < 2); +} + +/* Delete all paths except for one suspect one. */ +STATIC void +xrep_dirtree_keep_one_suspect_path( + struct xchk_dirtree *dl, + struct xchk_dirtree_outcomes *oc) +{ + struct xchk_dirpath *path; + bool foundit = false; + + xchk_dirtree_for_each_path(dl, path) { + switch (path->outcome) { + case XCHK_DIRPATH_CORRUPT: + case XCHK_DIRPATH_LOOP: + if (!foundit) { + xrep_dirpath_retain_parent(dl, path); + foundit = true; + continue; + } + oc->suspect--; + oc->bad++; + xrep_dirpath_set_outcome(dl, path, XCHK_DIRPATH_DELETE); + break; + case XCHK_DIRPATH_OK: + ASSERT(0); + break; + default: + break; + } + } + + ASSERT(oc->suspect == 1); + ASSERT(oc->good == 0); +} + +/* + * Figure out what to do with the paths we tried to find. Returns -EDEADLOCK + * if the scan results have become stale. + */ +STATIC void +xrep_dirtree_decide_fate( + struct xchk_dirtree *dl, + struct xchk_dirtree_outcomes *oc) +{ + xchk_dirtree_evaluate(dl, oc); + + /* Parentless directories should not have any paths at all. */ + if (xchk_dirtree_parentless(dl)) { + xrep_dirtree_delete_all_paths(dl, oc); + return; + } + + /* One path is exactly the number of paths we want. */ + if (oc->good + oc->suspect == 1) { + xrep_dirtree_find_surviving_path(dl, oc); + return; + } + + /* Zero paths means we should reattach the subdir to the orphanage. */ + if (oc->good + oc->suspect == 0) { + if (dl->sc->orphanage) + oc->needs_adoption = true; + return; + } + + /* + * Otherwise, this subdirectory has too many parents. If there's at + * least one good path, keep it and delete the others. + */ + if (oc->good > 0) { + xrep_dirtree_keep_one_good_path(dl, oc); + return; + } + + /* + * There are no good paths and there are too many suspect paths. + * Keep the first suspect path and delete the rest. + */ + xrep_dirtree_keep_one_suspect_path(dl, oc); +} + +/* + * Load the first step of this path into @step and @dl->xname/pptr + * for later repair work. + */ +STATIC int +xrep_dirtree_prep_path( + struct xchk_dirtree *dl, + struct xchk_dirpath *path, + struct xchk_dirpath_step *step) +{ + int error; + + error = xfarray_load(dl->path_steps, path->first_step, step); + if (error) + return error; + + error = xfblob_loadname(dl->path_names, step->name_cookie, &dl->xname, + step->name_len); + if (error) + return error; + + dl->pptr_rec = step->pptr_rec; /* struct copy */ + return 0; +} + +/* Delete the VFS dentry for a removed child. */ +STATIC int +xrep_dirtree_purge_dentry( + struct xchk_dirtree *dl, + struct xfs_inode *dp, + const struct xfs_name *name) +{ + struct qstr qname = QSTR_INIT(name->name, name->len); + struct dentry *parent_dentry, *child_dentry; + int error = 0; + + /* + * Find the dentry for the parent directory. If there isn't one, we're + * done. Caller already holds i_rwsem for parent and child. + */ + parent_dentry = d_find_alias(VFS_I(dp)); + if (!parent_dentry) + return 0; + + /* The VFS thinks the parent is a directory, right? */ + if (!d_is_dir(parent_dentry)) { + ASSERT(d_is_dir(parent_dentry)); + error = -EFSCORRUPTED; + goto out_dput_parent; + } + + /* + * Try to find the dirent pointing to the child. If there isn't one, + * we're done. + */ + qname.hash = full_name_hash(parent_dentry, name->name, name->len); + child_dentry = d_lookup(parent_dentry, &qname); + if (!child_dentry) { + error = 0; + goto out_dput_parent; + } + + trace_xrep_dirtree_delete_child(dp->i_mount, child_dentry); + + /* Child is not a directory? We're screwed. */ + if (!d_is_dir(child_dentry)) { + ASSERT(d_is_dir(child_dentry)); + error = -EFSCORRUPTED; + goto out_dput_child; + } + + /* Replace the child dentry with a negative one. */ + d_delete(child_dentry); + +out_dput_child: + dput(child_dentry); +out_dput_parent: + dput(parent_dentry); + return error; +} + +/* + * Prepare to delete a link by taking the IOLOCK of the parent and the child + * (scrub target). Caller must hold IOLOCK_EXCL on @sc->ip. Returns 0 if we + * took both locks, or a negative errno if we couldn't lock the parent in time. + */ +static inline int +xrep_dirtree_unlink_iolock( + struct xfs_scrub *sc, + struct xfs_inode *dp) +{ + int error; + + ASSERT(sc->ilock_flags & XFS_IOLOCK_EXCL); + + if (xfs_ilock_nowait(dp, XFS_IOLOCK_EXCL)) + return 0; + + xchk_iunlock(sc, XFS_IOLOCK_EXCL); + do { + xfs_ilock(dp, XFS_IOLOCK_EXCL); + if (xchk_ilock_nowait(sc, XFS_IOLOCK_EXCL)) + break; + xfs_iunlock(dp, XFS_IOLOCK_EXCL); + + if (xchk_should_terminate(sc, &error)) { + xchk_ilock(sc, XFS_IOLOCK_EXCL); + return error; + } + + delay(1); + } while (1); + + return 0; +} + +/* + * Remove a link from the directory tree and update the dcache. Returns + * -ESTALE if the scan data are now out of date. + */ +STATIC int +xrep_dirtree_unlink( + struct xchk_dirtree *dl, + struct xfs_inode *dp, + struct xchk_dirpath *path, + struct xchk_dirpath_step *step) +{ + struct xfs_scrub *sc = dl->sc; + struct xfs_mount *mp = sc->mp; + xfs_ino_t dotdot_ino; + xfs_ino_t parent_ino = dl->parent_ino; + unsigned int resblks; + int dontcare; + int error; + + /* Take IOLOCK_EXCL of the parent and child. */ + error = xrep_dirtree_unlink_iolock(sc, dp); + if (error) + return error; + + /* + * Create the transaction that we need to sever the path. Ignore + * EDQUOT and ENOSPC being returned via nospace_error because the + * directory code can handle a reservationless update. + */ + resblks = xfs_remove_space_res(mp, step->name_len); + error = xfs_trans_alloc_dir(dp, &M_RES(mp)->tr_remove, sc->ip, + &resblks, &sc->tp, &dontcare); + if (error) + goto out_iolock; + + /* + * Cancel if someone invalidate the paths while we were trying to get + * the ILOCK. + */ + mutex_lock(&dl->lock); + if (dl->stale) { + mutex_unlock(&dl->lock); + error = -ESTALE; + goto out_trans_cancel; + } + xrep_dirpath_set_outcome(dl, path, XREP_DIRPATH_DELETING); + mutex_unlock(&dl->lock); + + trace_xrep_dirtree_delete_path(dl->sc, sc->ip, path->path_nr, + &dl->xname, &dl->pptr_rec); + + /* + * Decide if we need to reset the dotdot entry. Rules: + * + * - If there's a surviving parent, we want dotdot to point there. + * - If we don't have any surviving parents, then point dotdot at the + * root dir. + * - If dotdot is already set to the value we want, pass in NULLFSINO + * for no change necessary. + * + * Do this /before/ we dirty anything, in case the dotdot lookup + * fails. + */ + error = xchk_dir_lookup(sc, sc->ip, &xfs_name_dotdot, &dotdot_ino); + if (error) + goto out_trans_cancel; + if (parent_ino == NULLFSINO) + parent_ino = dl->root_ino; + if (dotdot_ino == parent_ino) + parent_ino = NULLFSINO; + + /* Drop the link from sc->ip's dotdot entry. */ + error = xfs_droplink(sc->tp, dp); + if (error) + goto out_trans_cancel; + + /* Reset the dotdot entry to a surviving parent. */ + if (parent_ino != NULLFSINO) { + error = xfs_dir_replace(sc->tp, sc->ip, &xfs_name_dotdot, + parent_ino, 0); + if (error) + goto out_trans_cancel; + } + + /* Drop the link from dp to sc->ip. */ + error = xfs_droplink(sc->tp, sc->ip); + if (error) + goto out_trans_cancel; + + error = xfs_dir_removename(sc->tp, dp, &dl->xname, sc->ip->i_ino, + resblks); + if (error) { + ASSERT(error != -ENOENT); + goto out_trans_cancel; + } + + if (xfs_has_parent(sc->mp)) { + error = xfs_parent_removename(sc->tp, &dl->ppargs, dp, + &dl->xname, sc->ip); + if (error) + goto out_trans_cancel; + } + + /* + * Notify dirent hooks that we removed the bad link, invalidate the + * dcache, and commit the repair. + */ + xfs_dir_update_hook(dp, sc->ip, -1, &dl->xname); + error = xrep_dirtree_purge_dentry(dl, dp, &dl->xname); + if (error) + goto out_trans_cancel; + + error = xrep_trans_commit(sc); + goto out_ilock; + +out_trans_cancel: + xchk_trans_cancel(sc); +out_ilock: + xfs_iunlock(sc->ip, XFS_ILOCK_EXCL); + xfs_iunlock(dp, XFS_ILOCK_EXCL); +out_iolock: + xfs_iunlock(dp, XFS_IOLOCK_EXCL); + return error; +} + +/* + * Delete a directory entry that points to this directory. Returns -ESTALE + * if the scan data are now out of date. + */ +STATIC int +xrep_dirtree_delete_path( + struct xchk_dirtree *dl, + struct xchk_dirpath *path) +{ + struct xchk_dirpath_step step; + struct xfs_scrub *sc = dl->sc; + struct xfs_inode *dp; + int error; + + /* + * Load the parent pointer and directory inode for this path, then + * drop the scan lock, the ILOCK, and the transaction so that + * _delete_path can reserve the proper transaction. This sets up + * @dl->xname for the deletion. + */ + error = xrep_dirtree_prep_path(dl, path, &step); + if (error) + return error; + + error = xchk_iget(sc, be64_to_cpu(step.pptr_rec.p_ino), &dp); + if (error) + return error; + + mutex_unlock(&dl->lock); + xchk_trans_cancel(sc); + xchk_iunlock(sc, XFS_ILOCK_EXCL); + + /* Delete the directory link and release the parent. */ + error = xrep_dirtree_unlink(dl, dp, path, &step); + xchk_irele(sc, dp); + + /* + * Retake all the resources we had at the beginning even if the repair + * failed or the scan data are now stale. This keeps things simple for + * the caller. + */ + xchk_trans_alloc_empty(sc); + xchk_ilock(sc, XFS_ILOCK_EXCL); + mutex_lock(&dl->lock); + + if (!error && dl->stale) + error = -ESTALE; + return error; +} + +/* Add a new path to represent our in-progress adoption. */ +STATIC int +xrep_dirtree_create_adoption_path( + struct xchk_dirtree *dl) +{ + struct xfs_scrub *sc = dl->sc; + struct xchk_dirpath *path; + int error; + + /* + * We should have capped the number of paths at XFS_MAXLINK-1 in the + * scanner. + */ + if (dl->nr_paths > XFS_MAXLINK) { + ASSERT(dl->nr_paths <= XFS_MAXLINK); + return -EFSCORRUPTED; + } + + /* + * Create a new xchk_path structure to remember this parent pointer + * and record the first name step. + */ + path = kmalloc(sizeof(struct xchk_dirpath), XCHK_GFP_FLAGS); + if (!path) + return -ENOMEM; + + INIT_LIST_HEAD(&path->list); + xino_bitmap_init(&path->seen_inodes); + path->nr_steps = 0; + path->outcome = XREP_DIRPATH_ADOPTING; + + /* + * Record the new link that we just created in the orphanage. Because + * adoption is the last repair that we perform, we don't bother filling + * in the path all the way back to the root. + */ + xfs_inode_to_parent_rec(&dl->pptr_rec, sc->orphanage); + + error = xino_bitmap_set(&path->seen_inodes, sc->orphanage->i_ino); + if (error) + goto out_path; + + trace_xrep_dirtree_create_adoption(sc, sc->ip, dl->nr_paths, + &dl->xname, &dl->pptr_rec); + + error = xchk_dirpath_append(dl, sc->ip, path, &dl->xname, + &dl->pptr_rec); + if (error) + goto out_path; + + path->first_step = xfarray_length(dl->path_steps) - 1; + path->second_step = XFARRAY_NULLIDX; + path->path_nr = dl->nr_paths; + + list_add_tail(&path->list, &dl->path_list); + dl->nr_paths++; + return 0; + +out_path: + kfree(path); + return error; +} + +/* + * Prepare to move a file to the orphanage by taking the IOLOCK of the + * orphanage and the child (scrub target). Caller must hold IOLOCK_EXCL on + * @sc->ip. Returns 0 if we took both locks, or a negative errno if we + * couldn't lock the orphanage in time. + */ +static inline int +xrep_dirtree_adopt_iolock( + struct xfs_scrub *sc) +{ + int error; + + ASSERT(sc->ilock_flags & XFS_IOLOCK_EXCL); + + if (xrep_orphanage_ilock_nowait(sc, XFS_IOLOCK_EXCL)) + return 0; + + xchk_iunlock(sc, XFS_IOLOCK_EXCL); + do { + xrep_orphanage_ilock(sc, XFS_IOLOCK_EXCL); + if (xchk_ilock_nowait(sc, XFS_IOLOCK_EXCL)) + break; + xrep_orphanage_iunlock(sc, XFS_IOLOCK_EXCL); + + if (xchk_should_terminate(sc, &error)) { + xchk_ilock(sc, XFS_IOLOCK_EXCL); + return error; + } + + delay(1); + } while (1); + + return 0; +} + +/* + * Reattach this orphaned directory to the orphanage. Do not call this with + * any resources held. Returns -ESTALE if the scan data have become out of + * date. + */ +STATIC int +xrep_dirtree_adopt( + struct xchk_dirtree *dl) +{ + struct xfs_scrub *sc = dl->sc; + int error; + + /* Take the IOLOCK of the orphanage and the scrub target. */ + error = xrep_dirtree_adopt_iolock(sc); + if (error) + return error; + + /* + * Set up for an adoption. The directory tree fixer runs after the + * link counts have been corrected. Therefore, we must bump the + * child's link count since there will be no further opportunity to fix + * errors. + */ + error = xrep_adoption_trans_alloc(sc, &dl->adoption); + if (error) + goto out_iolock; + dl->adoption.bump_child_nlink = true; + + /* Figure out what name we're going to use here. */ + error = xrep_adoption_compute_name(&dl->adoption, &dl->xname); + if (error) + goto out_trans; + + /* + * Now that we have a proposed name for the orphanage entry, create + * a faux path so that the live update hook will see it. + */ + mutex_lock(&dl->lock); + if (dl->stale) { + mutex_unlock(&dl->lock); + error = -ESTALE; + goto out_trans; + } + error = xrep_dirtree_create_adoption_path(dl); + mutex_unlock(&dl->lock); + if (error) + goto out_trans; + + /* Reparent the directory. */ + error = xrep_adoption_move(&dl->adoption); + if (error) + goto out_trans; + + /* + * Commit the name and release all inode locks except for the scrub + * target's IOLOCK. + */ + error = xrep_trans_commit(sc); + goto out_ilock; + +out_trans: + xchk_trans_cancel(sc); +out_ilock: + xchk_iunlock(sc, XFS_ILOCK_EXCL); + xrep_orphanage_iunlock(sc, XFS_ILOCK_EXCL); +out_iolock: + xrep_orphanage_iunlock(sc, XFS_IOLOCK_EXCL); + return error; +} + +/* + * This newly orphaned directory needs to be adopted by the orphanage. + * Make this happen. + */ +STATIC int +xrep_dirtree_move_to_orphanage( + struct xchk_dirtree *dl) +{ + struct xfs_scrub *sc = dl->sc; + int error; + + /* + * Start by dropping all the resources that we hold so that we can grab + * all the resources that we need for the adoption. + */ + mutex_unlock(&dl->lock); + xchk_trans_cancel(sc); + xchk_iunlock(sc, XFS_ILOCK_EXCL); + + /* Perform the adoption. */ + error = xrep_dirtree_adopt(dl); + + /* + * Retake all the resources we had at the beginning even if the repair + * failed or the scan data are now stale. This keeps things simple for + * the caller. + */ + xchk_trans_alloc_empty(sc); + xchk_ilock(sc, XFS_ILOCK_EXCL); + mutex_lock(&dl->lock); + + if (!error && dl->stale) + error = -ESTALE; + return error; +} + +/* + * Try to fix all the problems. Returns -ESTALE if the scan data have become + * out of date. + */ +STATIC int +xrep_dirtree_fix_problems( + struct xchk_dirtree *dl, + struct xchk_dirtree_outcomes *oc) +{ + struct xchk_dirpath *path; + int error; + + /* Delete all the paths we don't want. */ + xchk_dirtree_for_each_path(dl, path) { + if (path->outcome != XCHK_DIRPATH_DELETE) + continue; + + error = xrep_dirtree_delete_path(dl, path); + if (error) + return error; + } + + /* Reparent this directory to the orphanage. */ + if (oc->needs_adoption) { + if (xrep_orphanage_can_adopt(dl->sc)) + return xrep_dirtree_move_to_orphanage(dl); + return -EFSCORRUPTED; + } + + return 0; +} + +/* Fix directory loops involving this directory. */ +int +xrep_dirtree( + struct xfs_scrub *sc) +{ + struct xchk_dirtree *dl = sc->buf; + struct xchk_dirtree_outcomes oc; + int error; + + /* + * Prepare to fix the directory tree by retaking the scan lock. The + * order of resource acquisition is still IOLOCK -> transaction -> + * ILOCK -> scan lock. + */ + mutex_lock(&dl->lock); + do { + /* + * Decide what we're going to do, then do it. An -ESTALE + * return here means the scan results are invalid and we have + * to walk again. + */ + if (!dl->stale) { + xrep_dirtree_decide_fate(dl, &oc); + + trace_xrep_dirtree_decided_fate(dl, &oc); + + error = xrep_dirtree_fix_problems(dl, &oc); + if (!error || error != -ESTALE) + break; + } + error = xchk_dirtree_find_paths_to_root(dl); + if (error == -ELNRNG || error == -ENOSR) + error = -EFSCORRUPTED; + } while (!error); + mutex_unlock(&dl->lock); + + return error; +} |