diff options
Diffstat (limited to 'fs/xfs/scrub/parent_repair.c')
| -rw-r--r-- | fs/xfs/scrub/parent_repair.c | 1612 |
1 files changed, 1612 insertions, 0 deletions
diff --git a/fs/xfs/scrub/parent_repair.c b/fs/xfs/scrub/parent_repair.c new file mode 100644 index 0000000000..7b42b7f65a --- /dev/null +++ b/fs/xfs/scrub/parent_repair.c @@ -0,0 +1,1612 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2020-2024 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_defer.h" +#include "xfs_bit.h" +#include "xfs_log_format.h" +#include "xfs_trans.h" +#include "xfs_sb.h" +#include "xfs_inode.h" +#include "xfs_icache.h" +#include "xfs_da_format.h" +#include "xfs_da_btree.h" +#include "xfs_dir2.h" +#include "xfs_bmap_btree.h" +#include "xfs_dir2_priv.h" +#include "xfs_trans_space.h" +#include "xfs_health.h" +#include "xfs_exchmaps.h" +#include "xfs_parent.h" +#include "xfs_attr.h" +#include "xfs_bmap.h" +#include "xfs_ag.h" +#include "scrub/xfs_scrub.h" +#include "scrub/scrub.h" +#include "scrub/common.h" +#include "scrub/trace.h" +#include "scrub/repair.h" +#include "scrub/iscan.h" +#include "scrub/findparent.h" +#include "scrub/readdir.h" +#include "scrub/tempfile.h" +#include "scrub/tempexch.h" +#include "scrub/orphanage.h" +#include "scrub/xfile.h" +#include "scrub/xfarray.h" +#include "scrub/xfblob.h" +#include "scrub/attr_repair.h" +#include "scrub/listxattr.h" + +/* + * Repairing The Directory Parent Pointer + * ====================================== + * + * Currently, only directories support parent pointers (in the form of '..' + * entries), so we simply scan the filesystem and update the '..' entry. + * + * Note that because the only parent pointer is the dotdot entry, we won't + * touch an unhealthy directory, since the directory repair code is perfectly + * capable of rebuilding a directory with the proper parent inode. + * + * See the section on locking issues in dir_repair.c for more information about + * conflicts with the VFS. The findparent code wll keep our incore parent + * inode up to date. + * + * If parent pointers are enabled, we instead reconstruct the parent pointer + * information by visiting every directory entry of every directory in the + * system and translating the relevant dirents into parent pointers. In this + * case, it is advantageous to stash all parent pointers created from dirents + * from a single parent file before replaying them into the temporary file. To + * save memory, the live filesystem scan reuses the findparent object. Parent + * pointer repair chooses either directory scanning or findparent, but not + * both. + * + * When salvaging completes, the remaining stashed entries are replayed to the + * temporary file. All non-parent pointer extended attributes are copied to + * the temporary file's extended attributes. An atomic file mapping exchange + * is used to commit the new xattr blocks to the file being repaired. This + * will disrupt attrmulti cursors. + */ + +/* Create a parent pointer in the tempfile. */ +#define XREP_PPTR_ADD (1) + +/* Remove a parent pointer from the tempfile. */ +#define XREP_PPTR_REMOVE (2) + +/* A stashed parent pointer update. */ +struct xrep_pptr { + /* Cookie for retrieval of the pptr name. */ + xfblob_cookie name_cookie; + + /* Parent pointer record. */ + struct xfs_parent_rec pptr_rec; + + /* Length of the pptr name. */ + uint8_t namelen; + + /* XREP_PPTR_{ADD,REMOVE} */ + uint8_t action; +}; + +/* + * Stash up to 8 pages of recovered parent pointers in pptr_recs and + * pptr_names before we write them to the temp file. + */ +#define XREP_PARENT_MAX_STASH_BYTES (PAGE_SIZE * 8) + +struct xrep_parent { + struct xfs_scrub *sc; + + /* Fixed-size array of xrep_pptr structures. */ + struct xfarray *pptr_recs; + + /* Blobs containing parent pointer names. */ + struct xfblob *pptr_names; + + /* xattr keys */ + struct xfarray *xattr_records; + + /* xattr values */ + struct xfblob *xattr_blobs; + + /* Scratch buffers for saving extended attributes */ + unsigned char *xattr_name; + void *xattr_value; + unsigned int xattr_value_sz; + + /* + * Information used to exchange the attr fork mappings, if the fs + * supports parent pointers. + */ + struct xrep_tempexch tx; + + /* + * Information used to scan the filesystem to find the inumber of the + * dotdot entry for this directory. On filesystems without parent + * pointers, we use the findparent_* functions on this object and + * access only the parent_ino field directly. + * + * When parent pointers are enabled, the directory entry scanner uses + * the iscan, hooks, and lock fields of this object directly. + * @pscan.lock coordinates access to pptr_recs, pptr_names, pptr, and + * pptr_scratch. This reduces the memory requirements of this + * structure. + * + * The lock also controls access to xattr_records and xattr_blobs(?) + */ + struct xrep_parent_scan_info pscan; + + /* Orphanage reparenting request. */ + struct xrep_adoption adoption; + + /* Directory entry name, plus the trailing null. */ + struct xfs_name xname; + unsigned char namebuf[MAXNAMELEN]; + + /* Scratch buffer for scanning pptr xattrs */ + struct xfs_da_args pptr_args; + + /* Have we seen any live updates of parent pointers recently? */ + bool saw_pptr_updates; + + /* Number of parents we found after all other repairs */ + unsigned long long parents; +}; + +struct xrep_parent_xattr { + /* Cookie for retrieval of the xattr name. */ + xfblob_cookie name_cookie; + + /* Cookie for retrieval of the xattr value. */ + xfblob_cookie value_cookie; + + /* XFS_ATTR_* flags */ + int flags; + + /* Length of the value and name. */ + uint32_t valuelen; + uint16_t namelen; +}; + +/* + * Stash up to 8 pages of attrs in xattr_records/xattr_blobs before we write + * them to the temp file. + */ +#define XREP_PARENT_XATTR_MAX_STASH_BYTES (PAGE_SIZE * 8) + +/* Tear down all the incore stuff we created. */ +static void +xrep_parent_teardown( + struct xrep_parent *rp) +{ + xrep_findparent_scan_teardown(&rp->pscan); + kvfree(rp->xattr_name); + rp->xattr_name = NULL; + kvfree(rp->xattr_value); + rp->xattr_value = NULL; + if (rp->xattr_blobs) + xfblob_destroy(rp->xattr_blobs); + rp->xattr_blobs = NULL; + if (rp->xattr_records) + xfarray_destroy(rp->xattr_records); + rp->xattr_records = NULL; + if (rp->pptr_names) + xfblob_destroy(rp->pptr_names); + rp->pptr_names = NULL; + if (rp->pptr_recs) + xfarray_destroy(rp->pptr_recs); + rp->pptr_recs = NULL; +} + +/* Set up for a parent repair. */ +int +xrep_setup_parent( + struct xfs_scrub *sc) +{ + struct xrep_parent *rp; + int error; + + xchk_fsgates_enable(sc, XCHK_FSGATES_DIRENTS); + + rp = kvzalloc(sizeof(struct xrep_parent), XCHK_GFP_FLAGS); + if (!rp) + return -ENOMEM; + rp->sc = sc; + rp->xname.name = rp->namebuf; + sc->buf = rp; + + error = xrep_tempfile_create(sc, S_IFREG); + if (error) + return error; + + return xrep_orphanage_try_create(sc); +} + +/* + * Scan all files in the filesystem for a child dirent that we can turn into + * the dotdot entry for this directory. + */ +STATIC int +xrep_parent_find_dotdot( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + xfs_ino_t ino; + unsigned int sick, checked; + int error; + + /* + * Avoid sick directories. There shouldn't be anyone else clearing the + * directory's sick status. + */ + xfs_inode_measure_sickness(sc->ip, &sick, &checked); + if (sick & XFS_SICK_INO_DIR) + return -EFSCORRUPTED; + + ino = xrep_findparent_self_reference(sc); + if (ino != NULLFSINO) { + xrep_findparent_scan_finish_early(&rp->pscan, ino); + return 0; + } + + /* + * Drop the ILOCK on this directory so that we can scan for the dotdot + * entry. Figure out who is going to be the parent of this directory, + * then retake the ILOCK so that we can salvage directory entries. + */ + xchk_iunlock(sc, XFS_ILOCK_EXCL); + + /* Does the VFS dcache have an answer for us? */ + ino = xrep_findparent_from_dcache(sc); + if (ino != NULLFSINO) { + error = xrep_findparent_confirm(sc, &ino); + if (!error && ino != NULLFSINO) { + xrep_findparent_scan_finish_early(&rp->pscan, ino); + goto out_relock; + } + } + + /* Scan the entire filesystem for a parent. */ + error = xrep_findparent_scan(&rp->pscan); +out_relock: + xchk_ilock(sc, XFS_ILOCK_EXCL); + + return error; +} + +/* + * Add this stashed incore parent pointer to the temporary file. + * The caller must hold the tempdir's IOLOCK, must not hold any ILOCKs, and + * must not be in transaction context. + */ +STATIC int +xrep_parent_replay_update( + struct xrep_parent *rp, + const struct xfs_name *xname, + struct xrep_pptr *pptr) +{ + struct xfs_scrub *sc = rp->sc; + + switch (pptr->action) { + case XREP_PPTR_ADD: + /* Create parent pointer. */ + trace_xrep_parent_replay_parentadd(sc->tempip, xname, + &pptr->pptr_rec); + + return xfs_parent_set(sc->tempip, sc->ip->i_ino, xname, + &pptr->pptr_rec, &rp->pptr_args); + case XREP_PPTR_REMOVE: + /* Remove parent pointer. */ + trace_xrep_parent_replay_parentremove(sc->tempip, xname, + &pptr->pptr_rec); + + return xfs_parent_unset(sc->tempip, sc->ip->i_ino, xname, + &pptr->pptr_rec, &rp->pptr_args); + } + + ASSERT(0); + return -EIO; +} + +/* + * Flush stashed parent pointer updates that have been recorded by the scanner. + * This is done to reduce the memory requirements of the parent pointer + * rebuild, since files can have a lot of hardlinks and the fs can be busy. + * + * Caller must not hold transactions or ILOCKs. Caller must hold the tempfile + * IOLOCK. + */ +STATIC int +xrep_parent_replay_updates( + struct xrep_parent *rp) +{ + xfarray_idx_t array_cur; + int error; + + mutex_lock(&rp->pscan.lock); + foreach_xfarray_idx(rp->pptr_recs, array_cur) { + struct xrep_pptr pptr; + + error = xfarray_load(rp->pptr_recs, array_cur, &pptr); + if (error) + goto out_unlock; + + error = xfblob_loadname(rp->pptr_names, pptr.name_cookie, + &rp->xname, pptr.namelen); + if (error) + goto out_unlock; + rp->xname.len = pptr.namelen; + mutex_unlock(&rp->pscan.lock); + + error = xrep_parent_replay_update(rp, &rp->xname, &pptr); + if (error) + return error; + + mutex_lock(&rp->pscan.lock); + } + + /* Empty out both arrays now that we've added the entries. */ + xfarray_truncate(rp->pptr_recs); + xfblob_truncate(rp->pptr_names); + mutex_unlock(&rp->pscan.lock); + return 0; +out_unlock: + mutex_unlock(&rp->pscan.lock); + return error; +} + +/* + * Remember that we want to create a parent pointer in the tempfile. These + * stashed actions will be replayed later. + */ +STATIC int +xrep_parent_stash_parentadd( + struct xrep_parent *rp, + const struct xfs_name *name, + const struct xfs_inode *dp) +{ + struct xrep_pptr pptr = { + .action = XREP_PPTR_ADD, + .namelen = name->len, + }; + int error; + + trace_xrep_parent_stash_parentadd(rp->sc->tempip, dp, name); + + xfs_inode_to_parent_rec(&pptr.pptr_rec, dp); + error = xfblob_storename(rp->pptr_names, &pptr.name_cookie, name); + if (error) + return error; + + return xfarray_append(rp->pptr_recs, &pptr); +} + +/* + * Remember that we want to remove a parent pointer from the tempfile. These + * stashed actions will be replayed later. + */ +STATIC int +xrep_parent_stash_parentremove( + struct xrep_parent *rp, + const struct xfs_name *name, + const struct xfs_inode *dp) +{ + struct xrep_pptr pptr = { + .action = XREP_PPTR_REMOVE, + .namelen = name->len, + }; + int error; + + trace_xrep_parent_stash_parentremove(rp->sc->tempip, dp, name); + + xfs_inode_to_parent_rec(&pptr.pptr_rec, dp); + error = xfblob_storename(rp->pptr_names, &pptr.name_cookie, name); + if (error) + return error; + + return xfarray_append(rp->pptr_recs, &pptr); +} + +/* + * Examine an entry of a directory. If this dirent leads us back to the file + * whose parent pointers we're rebuilding, add a pptr to the temporary + * directory. + */ +STATIC int +xrep_parent_scan_dirent( + struct xfs_scrub *sc, + struct xfs_inode *dp, + xfs_dir2_dataptr_t dapos, + const struct xfs_name *name, + xfs_ino_t ino, + void *priv) +{ + struct xrep_parent *rp = priv; + int error; + + /* Dirent doesn't point to this directory. */ + if (ino != rp->sc->ip->i_ino) + return 0; + + /* No weird looking names. */ + if (name->len == 0 || !xfs_dir2_namecheck(name->name, name->len)) + return -EFSCORRUPTED; + + /* No mismatching ftypes. */ + if (name->type != xfs_mode_to_ftype(VFS_I(sc->ip)->i_mode)) + return -EFSCORRUPTED; + + /* Don't pick up dot or dotdot entries; we only want child dirents. */ + if (xfs_dir2_samename(name, &xfs_name_dotdot) || + xfs_dir2_samename(name, &xfs_name_dot)) + return 0; + + /* + * Transform this dirent into a parent pointer and queue it for later + * addition to the temporary file. + */ + mutex_lock(&rp->pscan.lock); + error = xrep_parent_stash_parentadd(rp, name, dp); + mutex_unlock(&rp->pscan.lock); + return error; +} + +/* + * Decide if we want to look for dirents in this directory. Skip the file + * being repaired and any files being used to stage repairs. + */ +static inline bool +xrep_parent_want_scan( + struct xrep_parent *rp, + const struct xfs_inode *ip) +{ + return ip != rp->sc->ip && !xrep_is_tempfile(ip); +} + +/* + * Take ILOCK on a file that we want to scan. + * + * Select ILOCK_EXCL if the file is a directory with an unloaded data bmbt. + * Otherwise, take ILOCK_SHARED. + */ +static inline unsigned int +xrep_parent_scan_ilock( + struct xrep_parent *rp, + struct xfs_inode *ip) +{ + uint lock_mode = XFS_ILOCK_SHARED; + + /* Still need to take the shared ILOCK to advance the iscan cursor. */ + if (!xrep_parent_want_scan(rp, ip)) + goto lock; + + if (S_ISDIR(VFS_I(ip)->i_mode) && xfs_need_iread_extents(&ip->i_df)) { + lock_mode = XFS_ILOCK_EXCL; + goto lock; + } + +lock: + xfs_ilock(ip, lock_mode); + return lock_mode; +} + +/* + * Scan this file for relevant child dirents that point to the file whose + * parent pointers we're rebuilding. + */ +STATIC int +xrep_parent_scan_file( + struct xrep_parent *rp, + struct xfs_inode *ip) +{ + unsigned int lock_mode; + int error = 0; + + lock_mode = xrep_parent_scan_ilock(rp, ip); + + if (!xrep_parent_want_scan(rp, ip)) + goto scan_done; + + if (S_ISDIR(VFS_I(ip)->i_mode)) { + /* + * If the directory looks as though it has been zapped by the + * inode record repair code, we cannot scan for child dirents. + */ + if (xchk_dir_looks_zapped(ip)) { + error = -EBUSY; + goto scan_done; + } + + error = xchk_dir_walk(rp->sc, ip, xrep_parent_scan_dirent, rp); + if (error) + goto scan_done; + } + +scan_done: + xchk_iscan_mark_visited(&rp->pscan.iscan, ip); + xfs_iunlock(ip, lock_mode); + return error; +} + +/* Decide if we've stashed too much pptr data in memory. */ +static inline bool +xrep_parent_want_flush_stashed( + struct xrep_parent *rp) +{ + unsigned long long bytes; + + bytes = xfarray_bytes(rp->pptr_recs) + xfblob_bytes(rp->pptr_names); + return bytes > XREP_PARENT_MAX_STASH_BYTES; +} + +/* + * Scan all directories in the filesystem to look for dirents that we can turn + * into parent pointers. + */ +STATIC int +xrep_parent_scan_dirtree( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + struct xfs_inode *ip; + int error; + + /* + * Filesystem scans are time consuming. Drop the file ILOCK and all + * other resources for the duration of the scan and hope for the best. + * The live update hooks will keep our scan information up to date. + */ + xchk_trans_cancel(sc); + if (sc->ilock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) + xchk_iunlock(sc, sc->ilock_flags & (XFS_ILOCK_SHARED | + XFS_ILOCK_EXCL)); + error = xchk_trans_alloc_empty(sc); + if (error) + return error; + + while ((error = xchk_iscan_iter(&rp->pscan.iscan, &ip)) == 1) { + bool flush; + + error = xrep_parent_scan_file(rp, ip); + xchk_irele(sc, ip); + if (error) + break; + + /* Flush stashed pptr updates to constrain memory usage. */ + mutex_lock(&rp->pscan.lock); + flush = xrep_parent_want_flush_stashed(rp); + mutex_unlock(&rp->pscan.lock); + if (flush) { + xchk_trans_cancel(sc); + + error = xrep_tempfile_iolock_polled(sc); + if (error) + break; + + error = xrep_parent_replay_updates(rp); + xrep_tempfile_iounlock(sc); + if (error) + break; + + error = xchk_trans_alloc_empty(sc); + if (error) + break; + } + + if (xchk_should_terminate(sc, &error)) + break; + } + xchk_iscan_iter_finish(&rp->pscan.iscan); + if (error) { + /* + * If we couldn't grab an inode that was busy with a state + * change, change the error code so that we exit to userspace + * as quickly as possible. + */ + if (error == -EBUSY) + return -ECANCELED; + return error; + } + + /* + * Retake sc->ip's ILOCK now that we're done flushing stashed parent + * pointers. We end this function with an empty transaction and the + * ILOCK. + */ + xchk_ilock(rp->sc, XFS_ILOCK_EXCL); + return 0; +} + +/* + * Capture dirent updates being made by other threads which are relevant to the + * file being repaired. + */ +STATIC int +xrep_parent_live_update( + struct notifier_block *nb, + unsigned long action, + void *data) +{ + struct xfs_dir_update_params *p = data; + struct xrep_parent *rp; + struct xfs_scrub *sc; + int error; + + rp = container_of(nb, struct xrep_parent, pscan.dhook.dirent_hook.nb); + sc = rp->sc; + + /* + * This thread updated a dirent that points to the file that we're + * repairing, so stash the update for replay against the temporary + * file. + */ + if (p->ip->i_ino == sc->ip->i_ino && + xchk_iscan_want_live_update(&rp->pscan.iscan, p->dp->i_ino)) { + mutex_lock(&rp->pscan.lock); + if (p->delta > 0) + error = xrep_parent_stash_parentadd(rp, p->name, p->dp); + else + error = xrep_parent_stash_parentremove(rp, p->name, + p->dp); + if (!error) + rp->saw_pptr_updates = true; + mutex_unlock(&rp->pscan.lock); + if (error) + goto out_abort; + } + + return NOTIFY_DONE; +out_abort: + xchk_iscan_abort(&rp->pscan.iscan); + return NOTIFY_DONE; +} + +/* Reset a directory's dotdot entry, if needed. */ +STATIC int +xrep_parent_reset_dotdot( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + xfs_ino_t ino; + unsigned int spaceres; + int error = 0; + + ASSERT(sc->ilock_flags & XFS_ILOCK_EXCL); + + error = xchk_dir_lookup(sc, sc->ip, &xfs_name_dotdot, &ino); + if (error || ino == rp->pscan.parent_ino) + return error; + + xfs_trans_ijoin(sc->tp, sc->ip, 0); + + trace_xrep_parent_reset_dotdot(sc->ip, rp->pscan.parent_ino); + + /* + * Reserve more space just in case we have to expand the dir. We're + * allowed to exceed quota to repair inconsistent metadata. + */ + spaceres = xfs_rename_space_res(sc->mp, 0, false, xfs_name_dotdot.len, + false); + error = xfs_trans_reserve_more_inode(sc->tp, sc->ip, spaceres, 0, + true); + if (error) + return error; + + error = xfs_dir_replace(sc->tp, sc->ip, &xfs_name_dotdot, + rp->pscan.parent_ino, spaceres); + if (error) + return error; + + /* + * Roll transaction to detach the inode from the transaction but retain + * ILOCK_EXCL. + */ + return xfs_trans_roll(&sc->tp); +} + +/* Pass back the parent inumber if this a parent pointer */ +STATIC int +xrep_parent_lookup_pptr( + 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) +{ + xfs_ino_t *inop = priv; + xfs_ino_t parent_ino; + int error; + + if (!(attr_flags & XFS_ATTR_PARENT)) + return 0; + + error = xfs_parent_from_attr(sc->mp, attr_flags, name, namelen, value, + valuelen, &parent_ino, NULL); + if (error) + return error; + + *inop = parent_ino; + return -ECANCELED; +} + +/* + * Find the first parent of the scrub target by walking parent pointers for + * the purpose of deciding if we're going to move it to the orphanage. + * We don't care if the attr fork is zapped. + */ +STATIC int +xrep_parent_lookup_pptrs( + struct xfs_scrub *sc, + xfs_ino_t *inop) +{ + int error; + + *inop = NULLFSINO; + + error = xchk_xattr_walk(sc, sc->ip, xrep_parent_lookup_pptr, NULL, + inop); + if (error && error != -ECANCELED) + return error; + return 0; +} + +/* + * Move the current file to the orphanage. + * + * Caller must hold IOLOCK_EXCL on @sc->ip, and no other inode locks. Upon + * successful return, the scrub transaction will have enough extra reservation + * to make the move; it will hold IOLOCK_EXCL and ILOCK_EXCL of @sc->ip and the + * orphanage; and both inodes will be ijoined. + */ +STATIC int +xrep_parent_move_to_orphanage( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + xfs_ino_t orig_parent, new_parent; + int error; + + if (S_ISDIR(VFS_I(sc->ip)->i_mode)) { + /* + * We are about to drop the ILOCK on sc->ip to lock the + * orphanage and prepare for the adoption. Therefore, look up + * the old dotdot entry for sc->ip so that we can compare it + * after we re-lock sc->ip. + */ + error = xchk_dir_lookup(sc, sc->ip, &xfs_name_dotdot, + &orig_parent); + if (error) + return error; + } else { + /* + * We haven't dropped the ILOCK since we committed the new + * xattr structure (and hence the new parent pointer records), + * which means that the file cannot have been moved in the + * directory tree, and there are no parents. + */ + orig_parent = NULLFSINO; + } + + /* + * Drop the ILOCK on the scrub target and commit the transaction. + * Adoption computes its own resource requirements and gathers the + * necessary components. + */ + error = xrep_trans_commit(sc); + if (error) + return error; + xchk_iunlock(sc, XFS_ILOCK_EXCL); + + /* If we can take the orphanage's iolock then we're ready to move. */ + if (!xrep_orphanage_ilock_nowait(sc, XFS_IOLOCK_EXCL)) { + xchk_iunlock(sc, sc->ilock_flags); + error = xrep_orphanage_iolock_two(sc); + if (error) + return error; + } + + /* Grab transaction and ILOCK the two files. */ + error = xrep_adoption_trans_alloc(sc, &rp->adoption); + if (error) + return error; + + error = xrep_adoption_compute_name(&rp->adoption, &rp->xname); + if (error) + return error; + + /* + * Now that we've reacquired the ILOCK on sc->ip, look up the dotdot + * entry again. If the parent changed or the child was unlinked while + * the child directory was unlocked, we don't need to move the child to + * the orphanage after all. For a non-directory, we have to scan for + * the first parent pointer to see if one has been added. + */ + if (S_ISDIR(VFS_I(sc->ip)->i_mode)) + error = xchk_dir_lookup(sc, sc->ip, &xfs_name_dotdot, + &new_parent); + else + error = xrep_parent_lookup_pptrs(sc, &new_parent); + if (error) + return error; + + /* + * Attach to the orphanage if we still have a linked directory and it + * hasn't been moved. + */ + if (orig_parent == new_parent && VFS_I(sc->ip)->i_nlink > 0) { + error = xrep_adoption_move(&rp->adoption); + if (error) + return error; + } + + /* + * Launder the scrub transaction so we can drop the orphanage ILOCK + * and IOLOCK. Return holding the scrub target's ILOCK and IOLOCK. + */ + error = xrep_adoption_trans_roll(&rp->adoption); + if (error) + return error; + + xrep_orphanage_iunlock(sc, XFS_ILOCK_EXCL); + xrep_orphanage_iunlock(sc, XFS_IOLOCK_EXCL); + return 0; +} + +/* Ensure that the xattr value buffer is large enough. */ +STATIC int +xrep_parent_alloc_xattr_value( + struct xrep_parent *rp, + size_t bufsize) +{ + void *new_val; + + if (rp->xattr_value_sz >= bufsize) + return 0; + + if (rp->xattr_value) { + kvfree(rp->xattr_value); + rp->xattr_value = NULL; + rp->xattr_value_sz = 0; + } + + new_val = kvmalloc(bufsize, XCHK_GFP_FLAGS); + if (!new_val) + return -ENOMEM; + + rp->xattr_value = new_val; + rp->xattr_value_sz = bufsize; + return 0; +} + +/* Retrieve the (remote) value of a non-pptr xattr. */ +STATIC int +xrep_parent_fetch_xattr_remote( + struct xrep_parent *rp, + struct xfs_inode *ip, + unsigned int attr_flags, + const unsigned char *name, + unsigned int namelen, + unsigned int valuelen) +{ + struct xfs_scrub *sc = rp->sc; + struct xfs_da_args args = { + .attr_filter = attr_flags & XFS_ATTR_NSP_ONDISK_MASK, + .geo = sc->mp->m_attr_geo, + .whichfork = XFS_ATTR_FORK, + .dp = ip, + .name = name, + .namelen = namelen, + .trans = sc->tp, + .valuelen = valuelen, + .owner = ip->i_ino, + }; + int error; + + /* + * If we need a larger value buffer, try to allocate one. If that + * fails, return with -EDEADLOCK to try harder. + */ + error = xrep_parent_alloc_xattr_value(rp, valuelen); + if (error == -ENOMEM) + return -EDEADLOCK; + if (error) + return error; + + args.value = rp->xattr_value; + xfs_attr_sethash(&args); + return xfs_attr_get_ilocked(&args); +} + +/* Stash non-pptr attributes for later replay into the temporary file. */ +STATIC int +xrep_parent_stash_xattr( + 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 xrep_parent_xattr key = { + .valuelen = valuelen, + .namelen = namelen, + .flags = attr_flags & XFS_ATTR_NSP_ONDISK_MASK, + }; + struct xrep_parent *rp = priv; + int error; + + if (attr_flags & (XFS_ATTR_INCOMPLETE | XFS_ATTR_PARENT)) + return 0; + + if (!value) { + error = xrep_parent_fetch_xattr_remote(rp, ip, attr_flags, + name, namelen, valuelen); + if (error) + return error; + + value = rp->xattr_value; + } + + trace_xrep_parent_stash_xattr(rp->sc->tempip, key.flags, (void *)name, + key.namelen, key.valuelen); + + error = xfblob_store(rp->xattr_blobs, &key.name_cookie, name, + key.namelen); + if (error) + return error; + + error = xfblob_store(rp->xattr_blobs, &key.value_cookie, value, + key.valuelen); + if (error) + return error; + + return xfarray_append(rp->xattr_records, &key); +} + +/* Insert one xattr key/value. */ +STATIC int +xrep_parent_insert_xattr( + struct xrep_parent *rp, + const struct xrep_parent_xattr *key) +{ + struct xfs_da_args args = { + .dp = rp->sc->tempip, + .attr_filter = key->flags, + .namelen = key->namelen, + .valuelen = key->valuelen, + .owner = rp->sc->ip->i_ino, + .geo = rp->sc->mp->m_attr_geo, + .whichfork = XFS_ATTR_FORK, + .op_flags = XFS_DA_OP_OKNOENT, + }; + int error; + + ASSERT(!(key->flags & XFS_ATTR_PARENT)); + + /* + * Grab pointers to the scrub buffer so that we can use them to insert + * attrs into the temp file. + */ + args.name = rp->xattr_name; + args.value = rp->xattr_value; + + /* + * The attribute name is stored near the end of the in-core buffer, + * though we reserve one more byte to ensure null termination. + */ + rp->xattr_name[XATTR_NAME_MAX] = 0; + + error = xfblob_load(rp->xattr_blobs, key->name_cookie, rp->xattr_name, + key->namelen); + if (error) + return error; + + error = xfblob_free(rp->xattr_blobs, key->name_cookie); + if (error) + return error; + + error = xfblob_load(rp->xattr_blobs, key->value_cookie, args.value, + key->valuelen); + if (error) + return error; + + error = xfblob_free(rp->xattr_blobs, key->value_cookie); + if (error) + return error; + + rp->xattr_name[key->namelen] = 0; + + trace_xrep_parent_insert_xattr(rp->sc->tempip, key->flags, + rp->xattr_name, key->namelen, key->valuelen); + + xfs_attr_sethash(&args); + return xfs_attr_set(&args, XFS_ATTRUPDATE_UPSERT, false); +} + +/* + * Periodically flush salvaged attributes to the temporary file. This is done + * to reduce the memory requirements of the xattr rebuild because files can + * contain millions of attributes. + */ +STATIC int +xrep_parent_flush_xattrs( + struct xrep_parent *rp) +{ + xfarray_idx_t array_cur; + int error; + + /* + * Entering this function, the scrub context has a reference to the + * inode being repaired, the temporary file, and the empty scrub + * transaction that we created for the xattr scan. We hold ILOCK_EXCL + * on the inode being repaired. + * + * To constrain kernel memory use, we occasionally flush salvaged + * xattrs from the xfarray and xfblob structures into the temporary + * file in preparation for exchanging the xattr structures at the end. + * Updating the temporary file requires a transaction, so we commit the + * scrub transaction and drop the ILOCK so that xfs_attr_set can + * allocate whatever transaction it wants. + * + * We still hold IOLOCK_EXCL on the inode being repaired, which + * prevents anyone from adding xattrs (or parent pointers) while we're + * flushing. + */ + xchk_trans_cancel(rp->sc); + xchk_iunlock(rp->sc, XFS_ILOCK_EXCL); + + /* + * Take the IOLOCK of the temporary file while we modify xattrs. This + * isn't strictly required because the temporary file is never revealed + * to userspace, but we follow the same locking rules. We still hold + * sc->ip's IOLOCK. + */ + error = xrep_tempfile_iolock_polled(rp->sc); + if (error) + return error; + + /* Add all the salvaged attrs to the temporary file. */ + foreach_xfarray_idx(rp->xattr_records, array_cur) { + struct xrep_parent_xattr key; + + error = xfarray_load(rp->xattr_records, array_cur, &key); + if (error) + return error; + + error = xrep_parent_insert_xattr(rp, &key); + if (error) + return error; + } + + /* Empty out both arrays now that we've added the entries. */ + xfarray_truncate(rp->xattr_records); + xfblob_truncate(rp->xattr_blobs); + + xrep_tempfile_iounlock(rp->sc); + + /* Recreate the empty transaction and relock the inode. */ + error = xchk_trans_alloc_empty(rp->sc); + if (error) + return error; + xchk_ilock(rp->sc, XFS_ILOCK_EXCL); + return 0; +} + +/* Decide if we've stashed too much xattr data in memory. */ +static inline bool +xrep_parent_want_flush_xattrs( + struct xrep_parent *rp) +{ + unsigned long long bytes; + + bytes = xfarray_bytes(rp->xattr_records) + + xfblob_bytes(rp->xattr_blobs); + return bytes > XREP_PARENT_XATTR_MAX_STASH_BYTES; +} + +/* Flush staged attributes to the temporary file if we're over the limit. */ +STATIC int +xrep_parent_try_flush_xattrs( + struct xfs_scrub *sc, + void *priv) +{ + struct xrep_parent *rp = priv; + int error; + + if (!xrep_parent_want_flush_xattrs(rp)) + return 0; + + error = xrep_parent_flush_xattrs(rp); + if (error) + return error; + + /* + * If there were any parent pointer updates to the xattr structure + * while we dropped the ILOCK, the xattr structure is now stale. + * Signal to the attr copy process that we need to start over, but + * this time without opportunistic attr flushing. + * + * This is unlikely to happen, so we're ok with restarting the copy. + */ + mutex_lock(&rp->pscan.lock); + if (rp->saw_pptr_updates) + error = -ESTALE; + mutex_unlock(&rp->pscan.lock); + return error; +} + +/* Copy all the non-pptr extended attributes into the temporary file. */ +STATIC int +xrep_parent_copy_xattrs( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + int error; + + /* + * Clear the pptr updates flag. We hold sc->ip ILOCKed, so there + * can't be any parent pointer updates in progress. + */ + mutex_lock(&rp->pscan.lock); + rp->saw_pptr_updates = false; + mutex_unlock(&rp->pscan.lock); + + /* Copy xattrs, stopping periodically to flush the incore buffers. */ + error = xchk_xattr_walk(sc, sc->ip, xrep_parent_stash_xattr, + xrep_parent_try_flush_xattrs, rp); + if (error && error != -ESTALE) + return error; + + if (error == -ESTALE) { + /* + * The xattr copy collided with a parent pointer update. + * Restart the copy, but this time hold the ILOCK all the way + * to the end to lock out any directory parent pointer updates. + */ + error = xchk_xattr_walk(sc, sc->ip, xrep_parent_stash_xattr, + NULL, rp); + if (error) + return error; + } + + /* Flush any remaining stashed xattrs to the temporary file. */ + if (xfarray_bytes(rp->xattr_records) == 0) + return 0; + + return xrep_parent_flush_xattrs(rp); +} + +/* + * Ensure that @sc->ip and @sc->tempip both have attribute forks before we head + * into the attr fork exchange transaction. All files on a filesystem with + * parent pointers must have an attr fork because the parent pointer code does + * not itself add attribute forks. + * + * Note: Unlinkable unlinked files don't need one, but the overhead of having + * an unnecessary attr fork is not justified by the additional code complexity + * that would be needed to track that state correctly. + */ +STATIC int +xrep_parent_ensure_attr_fork( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + int error; + + error = xfs_attr_add_fork(sc->tempip, + sizeof(struct xfs_attr_sf_hdr), 1); + if (error) + return error; + return xfs_attr_add_fork(sc->ip, sizeof(struct xfs_attr_sf_hdr), 1); +} + +/* + * Finish replaying stashed parent pointer updates, allocate a transaction for + * exchanging extent mappings, and take the ILOCKs of both files before we + * commit the new attribute structure. + */ +STATIC int +xrep_parent_finalize_tempfile( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + int error; + + /* + * Repair relies on the ILOCK to quiesce all possible xattr updates. + * Replay all queued parent pointer updates into the tempfile before + * exchanging the contents, even if that means dropping the ILOCKs and + * the transaction. + */ + do { + error = xrep_parent_replay_updates(rp); + if (error) + return error; + + error = xrep_parent_ensure_attr_fork(rp); + if (error) + return error; + + error = xrep_tempexch_trans_alloc(sc, XFS_ATTR_FORK, &rp->tx); + if (error) + return error; + + if (xfarray_length(rp->pptr_recs) == 0) + break; + + xchk_trans_cancel(sc); + xrep_tempfile_iunlock_both(sc); + } while (!xchk_should_terminate(sc, &error)); + return error; +} + +/* + * Replay all the stashed parent pointers into the temporary file, copy all + * the non-pptr xattrs from the file being repaired into the temporary file, + * and exchange the attr fork contents atomically. + */ +STATIC int +xrep_parent_rebuild_pptrs( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + xfs_ino_t parent_ino = NULLFSINO; + int error; + + /* + * Copy non-ppttr xattrs from the file being repaired into the + * temporary file's xattr structure. We hold sc->ip's IOLOCK, which + * prevents setxattr/removexattr calls from occurring, but renames + * update the parent pointers without holding IOLOCK. If we detect + * stale attr structures, we restart the scan but only flush at the + * end. + */ + error = xrep_parent_copy_xattrs(rp); + if (error) + return error; + + /* + * Cancel the empty transaction that we used to walk and copy attrs, + * and drop the ILOCK so that we can take the IOLOCK on the temporary + * file. We still hold sc->ip's IOLOCK. + */ + xchk_trans_cancel(sc); + xchk_iunlock(sc, XFS_ILOCK_EXCL); + + error = xrep_tempfile_iolock_polled(sc); + if (error) + return error; + + /* + * Allocate transaction, lock inodes, and make sure that we've replayed + * all the stashed pptr updates to the tempdir. After this point, + * we're ready to exchange the attr fork mappings. + */ + error = xrep_parent_finalize_tempfile(rp); + if (error) + return error; + + /* Last chance to abort before we start committing pptr fixes. */ + if (xchk_should_terminate(sc, &error)) + return error; + + if (xchk_iscan_aborted(&rp->pscan.iscan)) + return -ECANCELED; + + /* + * Exchange the attr fork contents and junk the old attr fork contents, + * which are now in the tempfile. + */ + error = xrep_xattr_swap(sc, &rp->tx); + if (error) + return error; + error = xrep_xattr_reset_tempfile_fork(sc); + if (error) + return error; + + /* + * Roll to get a transaction without any inodes joined to it. Then we + * can drop the tempfile's ILOCK and IOLOCK before doing more work on + * the scrub target file. + */ + error = xfs_trans_roll(&sc->tp); + if (error) + return error; + xrep_tempfile_iunlock(sc); + xrep_tempfile_iounlock(sc); + + /* + * We've committed the new parent pointers. Find at least one parent + * so that we can decide if we're moving this file to the orphanage. + * For this purpose, root directories are their own parents. + */ + if (sc->ip == sc->mp->m_rootip) { + xrep_findparent_scan_found(&rp->pscan, sc->ip->i_ino); + } else { + error = xrep_parent_lookup_pptrs(sc, &parent_ino); + if (error) + return error; + if (parent_ino != NULLFSINO) + xrep_findparent_scan_found(&rp->pscan, parent_ino); + } + return 0; +} + +/* + * Commit the new parent pointer structure (currently only the dotdot entry) to + * the file that we're repairing. + */ +STATIC int +xrep_parent_rebuild_tree( + struct xrep_parent *rp) +{ + int error; + + if (xfs_has_parent(rp->sc->mp)) { + error = xrep_parent_rebuild_pptrs(rp); + if (error) + return error; + } + + if (rp->pscan.parent_ino == NULLFSINO) { + if (xrep_orphanage_can_adopt(rp->sc)) + return xrep_parent_move_to_orphanage(rp); + return -EFSCORRUPTED; + } + + if (S_ISDIR(VFS_I(rp->sc->ip)->i_mode)) + return xrep_parent_reset_dotdot(rp); + + return 0; +} + +/* Count the number of parent pointers. */ +STATIC int +xrep_parent_count_pptr( + 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 xrep_parent *rp = priv; + 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; + + rp->parents++; + return 0; +} + +/* + * After all parent pointer rebuilding and adoption activity completes, reset + * the link count of this nondirectory, having scanned the fs to rebuild all + * parent pointers. + */ +STATIC int +xrep_parent_set_nondir_nlink( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + struct xfs_inode *ip = sc->ip; + struct xfs_perag *pag; + bool joined = false; + int error; + + /* Count parent pointers so we can reset the file link count. */ + rp->parents = 0; + error = xchk_xattr_walk(sc, ip, xrep_parent_count_pptr, NULL, rp); + if (error) + return error; + + if (rp->parents > 0 && xfs_inode_on_unlinked_list(ip)) { + xfs_trans_ijoin(sc->tp, sc->ip, 0); + joined = true; + + /* + * The file is on the unlinked list but we found parents. + * Remove the file from the unlinked list. + */ + pag = xfs_perag_get(sc->mp, XFS_INO_TO_AGNO(sc->mp, ip->i_ino)); + if (!pag) { + ASSERT(0); + return -EFSCORRUPTED; + } + + error = xfs_iunlink_remove(sc->tp, pag, ip); + xfs_perag_put(pag); + if (error) + return error; + } else if (rp->parents == 0 && !xfs_inode_on_unlinked_list(ip)) { + xfs_trans_ijoin(sc->tp, sc->ip, 0); + joined = true; + + /* + * The file is not on the unlinked list but we found no + * parents. Add the file to the unlinked list. + */ + error = xfs_iunlink(sc->tp, ip); + if (error) + return error; + } + + /* Set the correct link count. */ + if (VFS_I(ip)->i_nlink != rp->parents) { + if (!joined) { + xfs_trans_ijoin(sc->tp, sc->ip, 0); + joined = true; + } + + set_nlink(VFS_I(ip), min_t(unsigned long long, rp->parents, + XFS_NLINK_PINNED)); + } + + /* Log the inode to keep it moving forward if we dirtied anything. */ + if (joined) + xfs_trans_log_inode(sc->tp, ip, XFS_ILOG_CORE); + return 0; +} + +/* Set up the filesystem scan so we can look for parents. */ +STATIC int +xrep_parent_setup_scan( + struct xrep_parent *rp) +{ + struct xfs_scrub *sc = rp->sc; + char *descr; + struct xfs_da_geometry *geo = sc->mp->m_attr_geo; + int max_len; + int error; + + if (!xfs_has_parent(sc->mp)) + return xrep_findparent_scan_start(sc, &rp->pscan); + + /* Buffers for copying non-pptr attrs to the tempfile */ + rp->xattr_name = kvmalloc(XATTR_NAME_MAX + 1, XCHK_GFP_FLAGS); + if (!rp->xattr_name) + return -ENOMEM; + + /* + * Allocate enough memory to handle loading local attr values from the + * xfblob data while flushing stashed attrs to the temporary file. + * We only realloc the buffer when salvaging remote attr values, so + * TRY_HARDER means we allocate the maximal attr value size. + */ + if (sc->flags & XCHK_TRY_HARDER) + max_len = XATTR_SIZE_MAX; + else + max_len = xfs_attr_leaf_entsize_local_max(geo->blksize); + error = xrep_parent_alloc_xattr_value(rp, max_len); + if (error) + goto out_xattr_name; + + /* Set up some staging memory for logging parent pointer updates. */ + descr = xchk_xfile_ino_descr(sc, "parent pointer entries"); + error = xfarray_create(descr, 0, sizeof(struct xrep_pptr), + &rp->pptr_recs); + kfree(descr); + if (error) + goto out_xattr_value; + + descr = xchk_xfile_ino_descr(sc, "parent pointer names"); + error = xfblob_create(descr, &rp->pptr_names); + kfree(descr); + if (error) + goto out_recs; + + /* Set up some storage for copying attrs before the mapping exchange */ + descr = xchk_xfile_ino_descr(sc, + "parent pointer retained xattr entries"); + error = xfarray_create(descr, 0, sizeof(struct xrep_parent_xattr), + &rp->xattr_records); + kfree(descr); + if (error) + goto out_names; + + descr = xchk_xfile_ino_descr(sc, + "parent pointer retained xattr values"); + error = xfblob_create(descr, &rp->xattr_blobs); + kfree(descr); + if (error) + goto out_attr_keys; + + error = __xrep_findparent_scan_start(sc, &rp->pscan, + xrep_parent_live_update); + if (error) + goto out_attr_values; + + return 0; + +out_attr_values: + xfblob_destroy(rp->xattr_blobs); + rp->xattr_blobs = NULL; +out_attr_keys: + xfarray_destroy(rp->xattr_records); + rp->xattr_records = NULL; +out_names: + xfblob_destroy(rp->pptr_names); + rp->pptr_names = NULL; +out_recs: + xfarray_destroy(rp->pptr_recs); + rp->pptr_recs = NULL; +out_xattr_value: + kvfree(rp->xattr_value); + rp->xattr_value = NULL; +out_xattr_name: + kvfree(rp->xattr_name); + rp->xattr_name = NULL; + return error; +} + +int +xrep_parent( + struct xfs_scrub *sc) +{ + struct xrep_parent *rp = sc->buf; + int error; + + /* + * When the parent pointers feature is enabled, repairs are committed + * by atomically committing a new xattr structure and reaping the old + * attr fork. Reaping requires rmap and exchange-range to be enabled. + */ + if (xfs_has_parent(sc->mp)) { + if (!xfs_has_rmapbt(sc->mp)) + return -EOPNOTSUPP; + if (!xfs_has_exchange_range(sc->mp)) + return -EOPNOTSUPP; + } + + error = xrep_parent_setup_scan(rp); + if (error) + return error; + + if (xfs_has_parent(sc->mp)) + error = xrep_parent_scan_dirtree(rp); + else + error = xrep_parent_find_dotdot(rp); + if (error) + goto out_teardown; + + /* Last chance to abort before we start committing dotdot fixes. */ + if (xchk_should_terminate(sc, &error)) + goto out_teardown; + + error = xrep_parent_rebuild_tree(rp); + if (error) + goto out_teardown; + if (xfs_has_parent(sc->mp) && !S_ISDIR(VFS_I(sc->ip)->i_mode)) { + error = xrep_parent_set_nondir_nlink(rp); + if (error) + goto out_teardown; + } + + error = xrep_defer_finish(sc); + +out_teardown: + xrep_parent_teardown(rp); + return error; +} |