diff options
Diffstat (limited to 'fs/xfs/scrub/dirtree.c')
| -rw-r--r-- | fs/xfs/scrub/dirtree.c | 985 |
1 files changed, 985 insertions, 0 deletions
diff --git a/fs/xfs/scrub/dirtree.c b/fs/xfs/scrub/dirtree.c new file mode 100644 index 000000000000..bde58fb561ea --- /dev/null +++ b/fs/xfs/scrub/dirtree.c @@ -0,0 +1,985 @@ +// 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_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" + +/* + * Directory Tree Structure Validation + * =================================== + * + * Validating the tree qualities of the directory tree structure can be + * difficult. If the tree is frozen, running a depth (or breadth) first search + * and marking a bitmap suffices to determine if there is a cycle. XORing the + * mark bitmap with the inode bitmap afterwards tells us if there are + * disconnected cycles. If the tree is not frozen, directory updates can move + * subtrees across the scanner wavefront, which complicates the design greatly. + * + * Directory parent pointers change that by enabling an incremental approach to + * validation of the tree structure. Instead of using one thread to scan the + * entire filesystem, we instead can have multiple threads walking individual + * subdirectories upwards to the root. In a perfect world, the IOLOCK would + * suffice to stabilize two directories in a parent -> child relationship. + * Unfortunately, the VFS does not take the IOLOCK when moving a child + * subdirectory, so we instead synchronize on ILOCK and use dirent update hooks + * to detect a race. If a race occurs in a path, we restart the scan. + * + * If the walk terminates without reaching the root, we know the path is + * disconnected and ought to be attached to the lost and found. If on the walk + * we find the same subdir that we're scanning, we know this is a cycle and + * should delete an incoming edge. If we find multiple paths to the root, we + * know to delete an incoming edge. + * + * There are two big hitches with this approach: first, all file link counts + * must be correct to prevent other writers from doing the wrong thing with the + * directory tree structure. Second, because we're walking upwards in a tree + * of arbitrary depth, we cannot hold all the ILOCKs. Instead, we will use a + * directory update hook to invalidate the scan results if one of the paths + * we've scanned has changed. + */ + +/* Clean up the dirtree checking resources. */ +STATIC void +xchk_dirtree_buf_cleanup( + void *buf) +{ + struct xchk_dirtree *dl = buf; + struct xchk_dirpath *path, *n; + + if (dl->scan_ino != NULLFSINO) + xfs_dir_hook_del(dl->sc->mp, &dl->dhook); + + xchk_dirtree_for_each_path_safe(dl, path, n) { + list_del_init(&path->list); + xino_bitmap_destroy(&path->seen_inodes); + kfree(path); + } + + xfblob_destroy(dl->path_names); + xfarray_destroy(dl->path_steps); + mutex_destroy(&dl->lock); +} + +/* Set us up to look for directory loops. */ +int +xchk_setup_dirtree( + struct xfs_scrub *sc) +{ + struct xchk_dirtree *dl; + char *descr; + int error; + + xchk_fsgates_enable(sc, XCHK_FSGATES_DIRENTS); + + if (xchk_could_repair(sc)) { + error = xrep_setup_dirtree(sc); + if (error) + return error; + } + + dl = kvzalloc(sizeof(struct xchk_dirtree), XCHK_GFP_FLAGS); + if (!dl) + return -ENOMEM; + dl->sc = sc; + dl->xname.name = dl->namebuf; + dl->hook_xname.name = dl->hook_namebuf; + INIT_LIST_HEAD(&dl->path_list); + dl->root_ino = NULLFSINO; + dl->scan_ino = NULLFSINO; + dl->parent_ino = NULLFSINO; + + mutex_init(&dl->lock); + + descr = xchk_xfile_ino_descr(sc, "dirtree path steps"); + error = xfarray_create(descr, 0, sizeof(struct xchk_dirpath_step), + &dl->path_steps); + kfree(descr); + if (error) + goto out_dl; + + descr = xchk_xfile_ino_descr(sc, "dirtree path names"); + error = xfblob_create(descr, &dl->path_names); + kfree(descr); + if (error) + goto out_steps; + + error = xchk_setup_inode_contents(sc, 0); + if (error) + goto out_names; + + sc->buf = dl; + sc->buf_cleanup = xchk_dirtree_buf_cleanup; + return 0; + +out_names: + xfblob_destroy(dl->path_names); +out_steps: + xfarray_destroy(dl->path_steps); +out_dl: + mutex_destroy(&dl->lock); + kvfree(dl); + return error; +} + +/* + * Add the parent pointer described by @dl->pptr to the given path as a new + * step. Returns -ELNRNG if the path is too deep. + */ +int +xchk_dirpath_append( + struct xchk_dirtree *dl, + struct xfs_inode *ip, + struct xchk_dirpath *path, + const struct xfs_name *name, + const struct xfs_parent_rec *pptr) +{ + struct xchk_dirpath_step step = { + .pptr_rec = *pptr, /* struct copy */ + .name_len = name->len, + }; + int error; + + /* + * If this path is more than 2 billion steps long, this directory tree + * is too far gone to fix. + */ + if (path->nr_steps >= XFS_MAXLINK) + return -ELNRNG; + + error = xfblob_storename(dl->path_names, &step.name_cookie, name); + if (error) + return error; + + error = xino_bitmap_set(&path->seen_inodes, ip->i_ino); + if (error) + return error; + + error = xfarray_append(dl->path_steps, &step); + if (error) + return error; + + path->nr_steps++; + return 0; +} + +/* + * Create an xchk_path for each parent pointer of the directory that we're + * scanning. For each path created, we will eventually try to walk towards the + * root with the goal of deleting all parents except for one that leads to the + * root. + * + * Returns -EFSCORRUPTED to signal that the inode being scanned has a corrupt + * parent pointer and hence there's no point in continuing; or -ENOSR if there + * are too many parent pointers for this directory. + */ +STATIC int +xchk_dirtree_create_path( + struct xfs_scrub *sc, + struct xfs_inode *ip, + unsigned int attr_flags, + const unsigned char *name, + unsigned int namelen, + const void *value, + unsigned int valuelen, + void *priv) +{ + struct xfs_name xname = { + .name = name, + .len = namelen, + }; + struct xchk_dirtree *dl = priv; + struct xchk_dirpath *path; + const struct xfs_parent_rec *rec = value; + int error; + + if (!(attr_flags & XFS_ATTR_PARENT)) + return 0; + + error = xfs_parent_from_attr(sc->mp, attr_flags, name, namelen, value, + valuelen, NULL, NULL); + if (error) + return error; + + /* + * If there are more than 2 billion actual parent pointers for this + * subdirectory, this fs is too far gone to fix. + */ + if (dl->nr_paths >= XFS_MAXLINK) + return -ENOSR; + + trace_xchk_dirtree_create_path(sc, ip, dl->nr_paths, &xname, rec); + + /* + * 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 = XCHK_DIRPATH_SCANNING; + + error = xchk_dirpath_append(dl, sc->ip, path, &xname, 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; +} + +/* + * Validate that the first step of this path still has a corresponding + * parent pointer in @sc->ip. We probably dropped @sc->ip's ILOCK while + * walking towards the roots, which is why this is necessary. + * + * This function has a side effect of loading the first parent pointer of this + * path into the parent pointer scratch pad. This prepares us to walk up the + * directory tree towards the root. Returns -ESTALE if the scan data is now + * out of date. + */ +STATIC int +xchk_dirpath_revalidate( + struct xchk_dirtree *dl, + struct xchk_dirpath *path) +{ + struct xfs_scrub *sc = dl->sc; + int error; + + /* + * Look up the parent pointer that corresponds to the start of this + * path. If the parent pointer has disappeared on us, dump all the + * scan results and try again. + */ + error = xfs_parent_lookup(sc->tp, sc->ip, &dl->xname, &dl->pptr_rec, + &dl->pptr_args); + if (error == -ENOATTR) { + trace_xchk_dirpath_disappeared(dl->sc, sc->ip, path->path_nr, + path->first_step, &dl->xname, &dl->pptr_rec); + dl->stale = true; + return -ESTALE; + } + + return error; +} + +/* + * Walk the parent pointers of a directory at the end of a path and record + * the parent that we find in @dl->xname/pptr_rec. + */ +STATIC int +xchk_dirpath_find_next_step( + struct xfs_scrub *sc, + struct xfs_inode *ip, + unsigned int attr_flags, + const unsigned char *name, + unsigned int namelen, + const void *value, + unsigned int valuelen, + void *priv) +{ + struct xchk_dirtree *dl = priv; + const struct xfs_parent_rec *rec = value; + int error; + + if (!(attr_flags & XFS_ATTR_PARENT)) + return 0; + + error = xfs_parent_from_attr(sc->mp, attr_flags, name, namelen, value, + valuelen, NULL, NULL); + if (error) + return error; + + /* + * If we've already set @dl->pptr_rec, then this directory has multiple + * parents. Signal this back to the caller via -EMLINK. + */ + if (dl->parents_found > 0) + return -EMLINK; + + dl->parents_found++; + memcpy(dl->namebuf, name, namelen); + dl->xname.len = namelen; + dl->pptr_rec = *rec; /* struct copy */ + return 0; +} + +/* Set and log the outcome of a path walk. */ +static inline void +xchk_dirpath_set_outcome( + struct xchk_dirtree *dl, + struct xchk_dirpath *path, + enum xchk_dirpath_outcome outcome) +{ + trace_xchk_dirpath_set_outcome(dl->sc, path->path_nr, path->nr_steps, + outcome); + + path->outcome = outcome; +} + +/* + * Scan the directory at the end of this path for its parent directory link. + * If we find one, extend the path. Returns -ESTALE if the scan data out of + * date. Returns -EFSCORRUPTED if the parent pointer is bad; or -ELNRNG if + * the path got too deep. + */ +STATIC int +xchk_dirpath_step_up( + struct xchk_dirtree *dl, + struct xchk_dirpath *path) +{ + struct xfs_scrub *sc = dl->sc; + struct xfs_inode *dp; + xfs_ino_t parent_ino = be64_to_cpu(dl->pptr_rec.p_ino); + unsigned int lock_mode; + int error; + + /* Grab and lock the parent directory. */ + error = xchk_iget(sc, parent_ino, &dp); + if (error) + return error; + + lock_mode = xfs_ilock_attr_map_shared(dp); + mutex_lock(&dl->lock); + + if (dl->stale) { + error = -ESTALE; + goto out_scanlock; + } + + /* We've reached the root directory; the path is ok. */ + if (parent_ino == dl->root_ino) { + xchk_dirpath_set_outcome(dl, path, XCHK_DIRPATH_OK); + error = 0; + goto out_scanlock; + } + + /* + * The inode being scanned is its own distant ancestor! Get rid of + * this path. + */ + if (parent_ino == sc->ip->i_ino) { + xchk_dirpath_set_outcome(dl, path, XCHK_DIRPATH_DELETE); + error = 0; + goto out_scanlock; + } + + /* + * We've seen this inode before during the path walk. There's a loop + * above us in the directory tree. This probably means that we cannot + * continue, but let's keep walking paths to get a full picture. + */ + if (xino_bitmap_test(&path->seen_inodes, parent_ino)) { + xchk_dirpath_set_outcome(dl, path, XCHK_DIRPATH_LOOP); + error = 0; + goto out_scanlock; + } + + /* The handle encoded in the parent pointer must match. */ + if (VFS_I(dp)->i_generation != be32_to_cpu(dl->pptr_rec.p_gen)) { + trace_xchk_dirpath_badgen(dl->sc, dp, path->path_nr, + path->nr_steps, &dl->xname, &dl->pptr_rec); + error = -EFSCORRUPTED; + goto out_scanlock; + } + + /* Parent pointer must point up to a directory. */ + if (!S_ISDIR(VFS_I(dp)->i_mode)) { + trace_xchk_dirpath_nondir_parent(dl->sc, dp, path->path_nr, + path->nr_steps, &dl->xname, &dl->pptr_rec); + error = -EFSCORRUPTED; + goto out_scanlock; + } + + /* Parent cannot be an unlinked directory. */ + if (VFS_I(dp)->i_nlink == 0) { + trace_xchk_dirpath_unlinked_parent(dl->sc, dp, path->path_nr, + path->nr_steps, &dl->xname, &dl->pptr_rec); + error = -EFSCORRUPTED; + goto out_scanlock; + } + + /* + * If the extended attributes look as though they has been zapped by + * the inode record repair code, we cannot scan for parent pointers. + */ + if (xchk_pptr_looks_zapped(dp)) { + error = -EBUSY; + xchk_set_incomplete(sc); + goto out_scanlock; + } + + /* + * Walk the parent pointers of @dp to find the parent of this directory + * to find the next step in our walk. If we find that @dp has exactly + * one parent, the parent pointer information will be stored in + * @dl->pptr_rec. This prepares us for the next step of the walk. + */ + mutex_unlock(&dl->lock); + dl->parents_found = 0; + error = xchk_xattr_walk(sc, dp, xchk_dirpath_find_next_step, NULL, dl); + mutex_lock(&dl->lock); + if (error == -EFSCORRUPTED || error == -EMLINK || + (!error && dl->parents_found == 0)) { + /* + * Further up the directory tree from @sc->ip, we found a + * corrupt parent pointer, multiple parent pointers while + * finding this directory's parent, or zero parents despite + * having a nonzero link count. Keep looking for other paths. + */ + xchk_dirpath_set_outcome(dl, path, XCHK_DIRPATH_CORRUPT); + error = 0; + goto out_scanlock; + } + if (error) + goto out_scanlock; + + if (dl->stale) { + error = -ESTALE; + goto out_scanlock; + } + + trace_xchk_dirpath_found_next_step(sc, dp, path->path_nr, + path->nr_steps, &dl->xname, &dl->pptr_rec); + + /* Append to the path steps */ + error = xchk_dirpath_append(dl, dp, path, &dl->xname, &dl->pptr_rec); + if (error) + goto out_scanlock; + + if (path->second_step == XFARRAY_NULLIDX) + path->second_step = xfarray_length(dl->path_steps) - 1; + +out_scanlock: + mutex_unlock(&dl->lock); + xfs_iunlock(dp, lock_mode); + xchk_irele(sc, dp); + return error; +} + +/* + * Walk the directory tree upwards towards what is hopefully the root + * directory, recording path steps as we go. The current path components are + * stored in dl->pptr_rec and dl->xname. + * + * Returns -ESTALE if the scan data are out of date. Returns -EFSCORRUPTED + * only if the direct parent pointer of @sc->ip associated with this path is + * corrupt. + */ +STATIC int +xchk_dirpath_walk_upwards( + struct xchk_dirtree *dl, + struct xchk_dirpath *path) +{ + struct xfs_scrub *sc = dl->sc; + int error; + + ASSERT(sc->ilock_flags & XFS_ILOCK_EXCL); + + /* Reload the start of this path and make sure it's still there. */ + error = xchk_dirpath_revalidate(dl, path); + if (error) + return error; + + trace_xchk_dirpath_walk_upwards(sc, sc->ip, path->path_nr, &dl->xname, + &dl->pptr_rec); + + /* + * The inode being scanned is its own direct ancestor! + * Get rid of this path. + */ + if (be64_to_cpu(dl->pptr_rec.p_ino) == sc->ip->i_ino) { + xchk_dirpath_set_outcome(dl, path, XCHK_DIRPATH_DELETE); + return 0; + } + + /* + * Drop ILOCK_EXCL on the inode being scanned. We still hold + * IOLOCK_EXCL on it, so it cannot move around or be renamed. + * + * Beyond this point we're walking up the directory tree, which means + * that we can acquire and drop the ILOCK on an alias of sc->ip. The + * ILOCK state is no longer tracked in the scrub context. Hence we + * must drop @sc->ip's ILOCK during the walk. + */ + mutex_unlock(&dl->lock); + xchk_iunlock(sc, XFS_ILOCK_EXCL); + + /* + * Take the first step in the walk towards the root by checking the + * start of this path, which is a direct parent pointer of @sc->ip. + * If we see any kind of error here (including corruptions), the parent + * pointer of @sc->ip is corrupt. Stop the whole scan. + */ + error = xchk_dirpath_step_up(dl, path); + if (error) { + xchk_ilock(sc, XFS_ILOCK_EXCL); + mutex_lock(&dl->lock); + return error; + } + + /* + * Take steps upward from the second step in this path towards the + * root. If we hit corruption errors here, there's a problem + * *somewhere* in the path, but we don't need to stop scanning. + */ + while (!error && path->outcome == XCHK_DIRPATH_SCANNING) + error = xchk_dirpath_step_up(dl, path); + + /* Retake the locks we had, mark paths, etc. */ + xchk_ilock(sc, XFS_ILOCK_EXCL); + mutex_lock(&dl->lock); + if (error == -EFSCORRUPTED) { + xchk_dirpath_set_outcome(dl, path, XCHK_DIRPATH_CORRUPT); + error = 0; + } + if (!error && dl->stale) + return -ESTALE; + return error; +} + +/* + * Decide if this path step has been touched by this live update. Returns + * 1 for yes, 0 for no, or a negative errno. + */ +STATIC int +xchk_dirpath_step_is_stale( + struct xchk_dirtree *dl, + struct xchk_dirpath *path, + unsigned int step_nr, + xfarray_idx_t step_idx, + struct xfs_dir_update_params *p, + xfs_ino_t *cursor) +{ + struct xchk_dirpath_step step; + xfs_ino_t child_ino = *cursor; + int error; + + error = xfarray_load(dl->path_steps, step_idx, &step); + if (error) + return error; + *cursor = be64_to_cpu(step.pptr_rec.p_ino); + + /* + * If the parent and child being updated are not the ones mentioned in + * this path step, the scan data is still ok. + */ + if (p->ip->i_ino != child_ino || p->dp->i_ino != *cursor) + return 0; + + /* + * If the dirent name lengths or byte sequences are different, the scan + * data is still ok. + */ + if (p->name->len != step.name_len) + return 0; + + error = xfblob_loadname(dl->path_names, step.name_cookie, + &dl->hook_xname, step.name_len); + if (error) + return error; + + if (memcmp(dl->hook_xname.name, p->name->name, p->name->len) != 0) + return 0; + + /* + * If the update comes from the repair code itself, walk the state + * machine forward. + */ + if (p->ip->i_ino == dl->scan_ino && + path->outcome == XREP_DIRPATH_ADOPTING) { + xchk_dirpath_set_outcome(dl, path, XREP_DIRPATH_ADOPTED); + return 0; + } + + if (p->ip->i_ino == dl->scan_ino && + path->outcome == XREP_DIRPATH_DELETING) { + xchk_dirpath_set_outcome(dl, path, XREP_DIRPATH_DELETED); + return 0; + } + + /* Exact match, scan data is out of date. */ + trace_xchk_dirpath_changed(dl->sc, path->path_nr, step_nr, p->dp, + p->ip, p->name); + return 1; +} + +/* + * Decide if this path has been touched by this live update. Returns 1 for + * yes, 0 for no, or a negative errno. + */ +STATIC int +xchk_dirpath_is_stale( + struct xchk_dirtree *dl, + struct xchk_dirpath *path, + struct xfs_dir_update_params *p) +{ + xfs_ino_t cursor = dl->scan_ino; + xfarray_idx_t idx = path->first_step; + unsigned int i; + int ret; + + /* + * The child being updated has not been seen by this path at all; this + * path cannot be stale. + */ + if (!xino_bitmap_test(&path->seen_inodes, p->ip->i_ino)) + return 0; + + ret = xchk_dirpath_step_is_stale(dl, path, 0, idx, p, &cursor); + if (ret != 0) + return ret; + + for (i = 1, idx = path->second_step; i < path->nr_steps; i++, idx++) { + ret = xchk_dirpath_step_is_stale(dl, path, i, idx, p, &cursor); + if (ret != 0) + return ret; + } + + return 0; +} + +/* + * Decide if a directory update from the regular filesystem touches any of the + * paths we've scanned, and invalidate the scan data if true. + */ +STATIC int +xchk_dirtree_live_update( + struct notifier_block *nb, + unsigned long action, + void *data) +{ + struct xfs_dir_update_params *p = data; + struct xchk_dirtree *dl; + struct xchk_dirpath *path; + int ret; + + dl = container_of(nb, struct xchk_dirtree, dhook.dirent_hook.nb); + + trace_xchk_dirtree_live_update(dl->sc, p->dp, action, p->ip, p->delta, + p->name); + + mutex_lock(&dl->lock); + + if (dl->stale || dl->aborted) + goto out_unlock; + + xchk_dirtree_for_each_path(dl, path) { + ret = xchk_dirpath_is_stale(dl, path, p); + if (ret < 0) { + dl->aborted = true; + break; + } + if (ret == 1) { + dl->stale = true; + break; + } + } + +out_unlock: + mutex_unlock(&dl->lock); + return NOTIFY_DONE; +} + +/* Delete all the collected path information. */ +STATIC void +xchk_dirtree_reset( + void *buf) +{ + struct xchk_dirtree *dl = buf; + struct xchk_dirpath *path, *n; + + ASSERT(dl->sc->ilock_flags & XFS_ILOCK_EXCL); + + xchk_dirtree_for_each_path_safe(dl, path, n) { + list_del_init(&path->list); + xino_bitmap_destroy(&path->seen_inodes); + kfree(path); + } + dl->nr_paths = 0; + + xfarray_truncate(dl->path_steps); + xfblob_truncate(dl->path_names); + + dl->stale = false; +} + +/* + * Load the name/pptr from the first step in this path into @dl->pptr_rec and + * @dl->xname. + */ +STATIC int +xchk_dirtree_load_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; +} + +/* + * For each parent pointer of this subdir, trace a path upwards towards the + * root directory and record what we find. Returns 0 for success; + * -EFSCORRUPTED if walking the parent pointers of @sc->ip failed, -ELNRNG if a + * path was too deep; -ENOSR if there were too many parent pointers; or + * a negative errno. + */ +int +xchk_dirtree_find_paths_to_root( + struct xchk_dirtree *dl) +{ + struct xfs_scrub *sc = dl->sc; + struct xchk_dirpath *path; + int error = 0; + + do { + if (xchk_should_terminate(sc, &error)) + return error; + + xchk_dirtree_reset(dl); + + /* + * If the extended attributes look as though they has been + * zapped by the inode record repair code, we cannot scan for + * parent pointers. + */ + if (xchk_pptr_looks_zapped(sc->ip)) { + xchk_set_incomplete(sc); + return -EBUSY; + } + + /* + * Create path walk contexts for each parent of the directory + * that is being scanned. Directories are supposed to have + * only one parent, but this is how we detect multiple parents. + */ + error = xchk_xattr_walk(sc, sc->ip, xchk_dirtree_create_path, + NULL, dl); + if (error) + return error; + + xchk_dirtree_for_each_path(dl, path) { + /* Load path components into dl->pptr/xname */ + error = xchk_dirtree_load_path(dl, path); + if (error) + return error; + + /* + * Try to walk up each path to the root. This enables + * us to find directory loops in ancestors, and the + * like. + */ + error = xchk_dirpath_walk_upwards(dl, path); + if (error == -EFSCORRUPTED) { + /* + * A parent pointer of @sc->ip is bad, don't + * bother continuing. + */ + break; + } + if (error == -ESTALE) { + /* This had better be an invalidation. */ + ASSERT(dl->stale); + break; + } + if (error) + return error; + if (dl->aborted) + return 0; + } + } while (dl->stale); + + return error; +} + +/* + * Figure out what to do with the paths we tried to find. Do not call this + * if the scan results are stale. + */ +void +xchk_dirtree_evaluate( + struct xchk_dirtree *dl, + struct xchk_dirtree_outcomes *oc) +{ + struct xchk_dirpath *path; + + ASSERT(!dl->stale); + + /* Scan the paths we have to decide what to do. */ + memset(oc, 0, sizeof(struct xchk_dirtree_outcomes)); + xchk_dirtree_for_each_path(dl, path) { + trace_xchk_dirpath_evaluate_path(dl->sc, path->path_nr, + path->nr_steps, path->outcome); + + switch (path->outcome) { + case XCHK_DIRPATH_SCANNING: + /* shouldn't get here */ + ASSERT(0); + break; + case XCHK_DIRPATH_DELETE: + /* This one is already going away. */ + oc->bad++; + break; + case XCHK_DIRPATH_CORRUPT: + case XCHK_DIRPATH_LOOP: + /* Couldn't find the end of this path. */ + oc->suspect++; + break; + case XCHK_DIRPATH_STALE: + /* shouldn't get here either */ + ASSERT(0); + break; + case XCHK_DIRPATH_OK: + /* This path got all the way to the root. */ + oc->good++; + break; + case XREP_DIRPATH_DELETING: + case XREP_DIRPATH_DELETED: + case XREP_DIRPATH_ADOPTING: + case XREP_DIRPATH_ADOPTED: + /* These should not be in progress! */ + ASSERT(0); + break; + } + } + + trace_xchk_dirtree_evaluate(dl, oc); +} + +/* Look for directory loops. */ +int +xchk_dirtree( + struct xfs_scrub *sc) +{ + struct xchk_dirtree_outcomes oc; + struct xchk_dirtree *dl = sc->buf; + int error; + + /* + * Nondirectories do not point downwards to other files, so they cannot + * cause a cycle in the directory tree. + */ + if (!S_ISDIR(VFS_I(sc->ip)->i_mode)) + return -ENOENT; + + ASSERT(xfs_has_parent(sc->mp)); + + /* + * Find the root of the directory tree. Remember which directory to + * scan, because the hook doesn't detach until after sc->ip gets + * released during teardown. + */ + dl->root_ino = sc->mp->m_rootip->i_ino; + dl->scan_ino = sc->ip->i_ino; + + trace_xchk_dirtree_start(sc->ip, sc->sm, 0); + + /* + * Hook into the directory entry code so that we can capture updates to + * paths that we have already scanned. The scanner thread takes each + * directory's ILOCK, which means that any in-progress directory update + * will finish before we can scan the directory. + */ + ASSERT(sc->flags & XCHK_FSGATES_DIRENTS); + xfs_dir_hook_setup(&dl->dhook, xchk_dirtree_live_update); + error = xfs_dir_hook_add(sc->mp, &dl->dhook); + if (error) + goto out; + + mutex_lock(&dl->lock); + + /* Trace each parent pointer's path to the root. */ + error = xchk_dirtree_find_paths_to_root(dl); + if (error == -EFSCORRUPTED || error == -ELNRNG || error == -ENOSR) { + /* + * Don't bother walking the paths if the xattr structure or the + * parent pointers are corrupt; this scan cannot be completed + * without full information. + */ + xchk_ino_xref_set_corrupt(sc, sc->ip->i_ino); + error = 0; + goto out_scanlock; + } + if (error == -EBUSY) { + /* + * We couldn't scan some directory's parent pointers because + * the attr fork looked like it had been zapped. The + * scan was marked incomplete, so no further error code + * is necessary. + */ + error = 0; + goto out_scanlock; + } + if (error) + goto out_scanlock; + if (dl->aborted) { + xchk_set_incomplete(sc); + goto out_scanlock; + } + + /* Assess what we found in our path evaluation. */ + xchk_dirtree_evaluate(dl, &oc); + if (xchk_dirtree_parentless(dl)) { + if (oc.good || oc.bad || oc.suspect) + xchk_ino_set_corrupt(sc, sc->ip->i_ino); + } else { + if (oc.bad || oc.good + oc.suspect != 1) + xchk_ino_set_corrupt(sc, sc->ip->i_ino); + if (oc.suspect) + xchk_ino_xref_set_corrupt(sc, sc->ip->i_ino); + } + +out_scanlock: + mutex_unlock(&dl->lock); +out: + trace_xchk_dirtree_done(sc->ip, sc->sm, error); + return error; +} |