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Diffstat (limited to '')
| -rw-r--r-- | fs/xfs/scrub/dir_repair.c | 1958 |
1 files changed, 1958 insertions, 0 deletions
diff --git a/fs/xfs/scrub/dir_repair.c b/fs/xfs/scrub/dir_repair.c new file mode 100644 index 0000000000..64679fe084 --- /dev/null +++ b/fs/xfs/scrub/dir_repair.c @@ -0,0 +1,1958 @@ +// 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_dir2_priv.h" +#include "xfs_bmap.h" +#include "xfs_quota.h" +#include "xfs_bmap_btree.h" +#include "xfs_trans_space.h" +#include "xfs_bmap_util.h" +#include "xfs_exchmaps.h" +#include "xfs_exchrange.h" +#include "xfs_ag.h" +#include "xfs_parent.h" +#include "scrub/xfs_scrub.h" +#include "scrub/scrub.h" +#include "scrub/common.h" +#include "scrub/trace.h" +#include "scrub/repair.h" +#include "scrub/tempfile.h" +#include "scrub/tempexch.h" +#include "scrub/xfile.h" +#include "scrub/xfarray.h" +#include "scrub/xfblob.h" +#include "scrub/iscan.h" +#include "scrub/readdir.h" +#include "scrub/reap.h" +#include "scrub/findparent.h" +#include "scrub/orphanage.h" +#include "scrub/listxattr.h" + +/* + * Directory Repair + * ================ + * + * We repair directories by reading the directory data blocks looking for + * directory entries that look salvageable (name passes verifiers, entry points + * to a valid allocated inode, etc). Each entry worth salvaging is stashed in + * memory, and the stashed entries are periodically replayed into a temporary + * directory to constrain memory use. Batching the construction of the + * temporary directory in this fashion reduces lock cycling of the directory + * being repaired and the temporary directory, and will later become important + * for parent pointer scanning. + * + * If parent pointers are enabled on this filesystem, we instead reconstruct + * the directory by visiting each parent pointer of each file in the filesystem + * and translating the relevant parent pointer records into dirents. In this + * case, it is advantageous to stash all directory entries created from parent + * pointers for a single child file before replaying them into the temporary + * directory. To save memory, the live filesystem scan reuses the findparent + * fields. Directory repair chooses either parent pointer scanning or + * directory entry salvaging, but not both. + * + * Directory entries added to the temporary directory do not elevate the link + * counts of the inodes found. When salvaging completes, the remaining stashed + * entries are replayed to the temporary directory. An atomic mapping exchange + * is used to commit the new directory blocks to the directory being repaired. + * This will disrupt readdir cursors. + * + * Locking Issues + * -------------- + * + * If /a, /a/b, and /c are all directories, the VFS does not take i_rwsem on + * /a/b for a "mv /a/b /c/" operation. This means that only b's ILOCK protects + * b's dotdot update. This is in contrast to every other dotdot update (link, + * remove, mkdir). If the repair code drops the ILOCK, it must either + * revalidate the dotdot entry or use dirent hooks to capture updates from + * other threads. + */ + +/* Create a dirent in the tempdir. */ +#define XREP_DIRENT_ADD (1) + +/* Remove a dirent from the tempdir. */ +#define XREP_DIRENT_REMOVE (2) + +/* Directory entry to be restored in the new directory. */ +struct xrep_dirent { + /* Cookie for retrieval of the dirent name. */ + xfblob_cookie name_cookie; + + /* Target inode number. */ + xfs_ino_t ino; + + /* Length of the dirent name. */ + uint8_t namelen; + + /* File type of the dirent. */ + uint8_t ftype; + + /* XREP_DIRENT_{ADD,REMOVE} */ + uint8_t action; +}; + +/* + * Stash up to 8 pages of recovered dirent data in dir_entries and dir_names + * before we write them to the temp dir. + */ +#define XREP_DIR_MAX_STASH_BYTES (PAGE_SIZE * 8) + +struct xrep_dir { + struct xfs_scrub *sc; + + /* Fixed-size array of xrep_dirent structures. */ + struct xfarray *dir_entries; + + /* Blobs containing directory entry names. */ + struct xfblob *dir_names; + + /* Information for exchanging data forks at the end. */ + struct xrep_tempexch tx; + + /* Preallocated args struct for performing dir operations */ + struct xfs_da_args args; + + /* + * Information used to scan the filesystem to find the inumber of the + * dotdot entry for this directory. For directory salvaging when + * parent pointers are not enabled, we use the findparent_* functions + * on this object and access only the parent_ino field directly. + * + * When parent pointers are enabled, however, the pptr scanner uses the + * iscan, hooks, lock, and parent_ino fields of this object directly. + * @pscan.lock coordinates access to dir_entries, dir_names, + * parent_ino, subdirs, dirents, and args. This reduces the memory + * requirements of this structure. + */ + struct xrep_parent_scan_info pscan; + + /* + * Context information for attaching this directory to the lost+found + * if this directory does not have a parent. + */ + struct xrep_adoption adoption; + + /* How many subdirectories did we find? */ + uint64_t subdirs; + + /* How many dirents did we find? */ + unsigned int dirents; + + /* Should we move this directory to the orphanage? */ + bool needs_adoption; + + /* Directory entry name, plus the trailing null. */ + struct xfs_name xname; + unsigned char namebuf[MAXNAMELEN]; +}; + +/* Tear down all the incore stuff we created. */ +static void +xrep_dir_teardown( + struct xfs_scrub *sc) +{ + struct xrep_dir *rd = sc->buf; + + xrep_findparent_scan_teardown(&rd->pscan); + xfblob_destroy(rd->dir_names); + xfarray_destroy(rd->dir_entries); +} + +/* Set up for a directory repair. */ +int +xrep_setup_directory( + struct xfs_scrub *sc) +{ + struct xrep_dir *rd; + int error; + + xchk_fsgates_enable(sc, XCHK_FSGATES_DIRENTS); + + error = xrep_orphanage_try_create(sc); + if (error) + return error; + + error = xrep_tempfile_create(sc, S_IFDIR); + if (error) + return error; + + rd = kvzalloc(sizeof(struct xrep_dir), XCHK_GFP_FLAGS); + if (!rd) + return -ENOMEM; + rd->sc = sc; + rd->xname.name = rd->namebuf; + sc->buf = rd; + + return 0; +} + +/* + * Look up the dotdot entry and confirm that it's really the parent. + * Returns NULLFSINO if we don't know what to do. + */ +static inline xfs_ino_t +xrep_dir_lookup_parent( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + xfs_ino_t ino; + int error; + + error = xfs_dir_lookup(sc->tp, sc->ip, &xfs_name_dotdot, &ino, NULL); + if (error) + return NULLFSINO; + if (!xfs_verify_dir_ino(sc->mp, ino)) + return NULLFSINO; + + error = xrep_findparent_confirm(sc, &ino); + if (error) + return NULLFSINO; + + return ino; +} + +/* + * Look up '..' in the dentry cache and confirm that it's really the parent. + * Returns NULLFSINO if the dcache misses or if the hit is implausible. + */ +static inline xfs_ino_t +xrep_dir_dcache_parent( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + xfs_ino_t parent_ino; + int error; + + parent_ino = xrep_findparent_from_dcache(sc); + if (parent_ino == NULLFSINO) + return parent_ino; + + error = xrep_findparent_confirm(sc, &parent_ino); + if (error) + return NULLFSINO; + + return parent_ino; +} + +/* Try to find the parent of the directory being repaired. */ +STATIC int +xrep_dir_find_parent( + struct xrep_dir *rd) +{ + xfs_ino_t ino; + + ino = xrep_findparent_self_reference(rd->sc); + if (ino != NULLFSINO) { + xrep_findparent_scan_finish_early(&rd->pscan, ino); + return 0; + } + + ino = xrep_dir_dcache_parent(rd); + if (ino != NULLFSINO) { + xrep_findparent_scan_finish_early(&rd->pscan, ino); + return 0; + } + + ino = xrep_dir_lookup_parent(rd); + if (ino != NULLFSINO) { + xrep_findparent_scan_finish_early(&rd->pscan, ino); + return 0; + } + + /* + * A full filesystem scan is the last resort. On a busy filesystem, + * the scan can fail with -EBUSY if we cannot grab IOLOCKs. That means + * that we don't know what who the parent is, so we should return to + * userspace. + */ + return xrep_findparent_scan(&rd->pscan); +} + +/* + * Decide if we want to salvage this entry. We don't bother with oversized + * names or the dot entry. + */ +STATIC int +xrep_dir_want_salvage( + struct xrep_dir *rd, + const char *name, + int namelen, + xfs_ino_t ino) +{ + struct xfs_mount *mp = rd->sc->mp; + + /* No pointers to ourselves or to garbage. */ + if (ino == rd->sc->ip->i_ino) + return false; + if (!xfs_verify_dir_ino(mp, ino)) + return false; + + /* No weird looking names or dot entries. */ + if (namelen >= MAXNAMELEN || namelen <= 0) + return false; + if (namelen == 1 && name[0] == '.') + return false; + if (!xfs_dir2_namecheck(name, namelen)) + return false; + + return true; +} + +/* + * Remember that we want to create a dirent in the tempdir. These stashed + * actions will be replayed later. + */ +STATIC int +xrep_dir_stash_createname( + struct xrep_dir *rd, + const struct xfs_name *name, + xfs_ino_t ino) +{ + struct xrep_dirent dirent = { + .action = XREP_DIRENT_ADD, + .ino = ino, + .namelen = name->len, + .ftype = name->type, + }; + int error; + + trace_xrep_dir_stash_createname(rd->sc->tempip, name, ino); + + error = xfblob_storename(rd->dir_names, &dirent.name_cookie, name); + if (error) + return error; + + return xfarray_append(rd->dir_entries, &dirent); +} + +/* + * Remember that we want to remove a dirent from the tempdir. These stashed + * actions will be replayed later. + */ +STATIC int +xrep_dir_stash_removename( + struct xrep_dir *rd, + const struct xfs_name *name, + xfs_ino_t ino) +{ + struct xrep_dirent dirent = { + .action = XREP_DIRENT_REMOVE, + .ino = ino, + .namelen = name->len, + .ftype = name->type, + }; + int error; + + trace_xrep_dir_stash_removename(rd->sc->tempip, name, ino); + + error = xfblob_storename(rd->dir_names, &dirent.name_cookie, name); + if (error) + return error; + + return xfarray_append(rd->dir_entries, &dirent); +} + +/* Allocate an in-core record to hold entries while we rebuild the dir data. */ +STATIC int +xrep_dir_salvage_entry( + struct xrep_dir *rd, + unsigned char *name, + unsigned int namelen, + xfs_ino_t ino) +{ + struct xfs_name xname = { + .name = name, + }; + struct xfs_scrub *sc = rd->sc; + struct xfs_inode *ip; + unsigned int i = 0; + int error = 0; + + if (xchk_should_terminate(sc, &error)) + return error; + + /* + * Truncate the name to the first character that would trip namecheck. + * If we no longer have a name after that, ignore this entry. + */ + while (i < namelen && name[i] != 0 && name[i] != '/') + i++; + if (i == 0) + return 0; + xname.len = i; + + /* Ignore '..' entries; we already picked the new parent. */ + if (xname.len == 2 && name[0] == '.' && name[1] == '.') { + trace_xrep_dir_salvaged_parent(sc->ip, ino); + return 0; + } + + trace_xrep_dir_salvage_entry(sc->ip, &xname, ino); + + /* + * Compute the ftype or dump the entry if we can't. We don't lock the + * inode because inodes can't change type while we have a reference. + */ + error = xchk_iget(sc, ino, &ip); + if (error) + return 0; + + xname.type = xfs_mode_to_ftype(VFS_I(ip)->i_mode); + xchk_irele(sc, ip); + + return xrep_dir_stash_createname(rd, &xname, ino); +} + +/* Record a shortform directory entry for later reinsertion. */ +STATIC int +xrep_dir_salvage_sf_entry( + struct xrep_dir *rd, + struct xfs_dir2_sf_hdr *sfp, + struct xfs_dir2_sf_entry *sfep) +{ + xfs_ino_t ino; + + ino = xfs_dir2_sf_get_ino(rd->sc->mp, sfp, sfep); + if (!xrep_dir_want_salvage(rd, sfep->name, sfep->namelen, ino)) + return 0; + + return xrep_dir_salvage_entry(rd, sfep->name, sfep->namelen, ino); +} + +/* Record a regular directory entry for later reinsertion. */ +STATIC int +xrep_dir_salvage_data_entry( + struct xrep_dir *rd, + struct xfs_dir2_data_entry *dep) +{ + xfs_ino_t ino; + + ino = be64_to_cpu(dep->inumber); + if (!xrep_dir_want_salvage(rd, dep->name, dep->namelen, ino)) + return 0; + + return xrep_dir_salvage_entry(rd, dep->name, dep->namelen, ino); +} + +/* Try to recover block/data format directory entries. */ +STATIC int +xrep_dir_recover_data( + struct xrep_dir *rd, + struct xfs_buf *bp) +{ + struct xfs_da_geometry *geo = rd->sc->mp->m_dir_geo; + unsigned int offset; + unsigned int end; + int error = 0; + + /* + * Loop over the data portion of the block. + * Each object is a real entry (dep) or an unused one (dup). + */ + offset = geo->data_entry_offset; + end = min_t(unsigned int, BBTOB(bp->b_length), + xfs_dir3_data_end_offset(geo, bp->b_addr)); + + while (offset < end) { + struct xfs_dir2_data_unused *dup = bp->b_addr + offset; + struct xfs_dir2_data_entry *dep = bp->b_addr + offset; + + if (xchk_should_terminate(rd->sc, &error)) + return error; + + /* Skip unused entries. */ + if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) { + offset += be16_to_cpu(dup->length); + continue; + } + + /* Don't walk off the end of the block. */ + offset += xfs_dir2_data_entsize(rd->sc->mp, dep->namelen); + if (offset > end) + break; + + /* Ok, let's save this entry. */ + error = xrep_dir_salvage_data_entry(rd, dep); + if (error) + return error; + + } + + return 0; +} + +/* Try to recover shortform directory entries. */ +STATIC int +xrep_dir_recover_sf( + struct xrep_dir *rd) +{ + struct xfs_dir2_sf_hdr *hdr; + struct xfs_dir2_sf_entry *sfep; + struct xfs_dir2_sf_entry *next; + struct xfs_ifork *ifp; + xfs_ino_t ino; + unsigned char *end; + int error = 0; + + ifp = xfs_ifork_ptr(rd->sc->ip, XFS_DATA_FORK); + hdr = ifp->if_data; + end = (unsigned char *)ifp->if_data + ifp->if_bytes; + + ino = xfs_dir2_sf_get_parent_ino(hdr); + trace_xrep_dir_salvaged_parent(rd->sc->ip, ino); + + sfep = xfs_dir2_sf_firstentry(hdr); + while ((unsigned char *)sfep < end) { + if (xchk_should_terminate(rd->sc, &error)) + return error; + + next = xfs_dir2_sf_nextentry(rd->sc->mp, hdr, sfep); + if ((unsigned char *)next > end) + break; + + /* Ok, let's save this entry. */ + error = xrep_dir_salvage_sf_entry(rd, hdr, sfep); + if (error) + return error; + + sfep = next; + } + + return 0; +} + +/* + * Try to figure out the format of this directory from the data fork mappings + * and the directory size. If we can be reasonably sure of format, we can be + * more aggressive in salvaging directory entries. On return, @magic_guess + * will be set to DIR3_BLOCK_MAGIC if we think this is a "block format" + * directory; DIR3_DATA_MAGIC if we think this is a "data format" directory, + * and 0 if we can't tell. + */ +STATIC void +xrep_dir_guess_format( + struct xrep_dir *rd, + __be32 *magic_guess) +{ + struct xfs_inode *dp = rd->sc->ip; + struct xfs_mount *mp = rd->sc->mp; + struct xfs_da_geometry *geo = mp->m_dir_geo; + xfs_fileoff_t last; + int error; + + ASSERT(xfs_has_crc(mp)); + + *magic_guess = 0; + + /* + * If there's a single directory block and the directory size is + * exactly one block, this has to be a single block format directory. + */ + error = xfs_bmap_last_offset(dp, &last, XFS_DATA_FORK); + if (!error && XFS_FSB_TO_B(mp, last) == geo->blksize && + dp->i_disk_size == geo->blksize) { + *magic_guess = cpu_to_be32(XFS_DIR3_BLOCK_MAGIC); + return; + } + + /* + * If the last extent before the leaf offset matches the directory + * size and the directory size is larger than 1 block, this is a + * data format directory. + */ + last = geo->leafblk; + error = xfs_bmap_last_before(rd->sc->tp, dp, &last, XFS_DATA_FORK); + if (!error && + XFS_FSB_TO_B(mp, last) > geo->blksize && + XFS_FSB_TO_B(mp, last) == dp->i_disk_size) { + *magic_guess = cpu_to_be32(XFS_DIR3_DATA_MAGIC); + return; + } +} + +/* Recover directory entries from a specific directory block. */ +STATIC int +xrep_dir_recover_dirblock( + struct xrep_dir *rd, + __be32 magic_guess, + xfs_dablk_t dabno) +{ + struct xfs_dir2_data_hdr *hdr; + struct xfs_buf *bp; + __be32 oldmagic; + int error; + + /* + * Try to read buffer. We invalidate them in the next step so we don't + * bother to set a buffer type or ops. + */ + error = xfs_da_read_buf(rd->sc->tp, rd->sc->ip, dabno, + XFS_DABUF_MAP_HOLE_OK, &bp, XFS_DATA_FORK, NULL); + if (error || !bp) + return error; + + hdr = bp->b_addr; + oldmagic = hdr->magic; + + trace_xrep_dir_recover_dirblock(rd->sc->ip, dabno, + be32_to_cpu(hdr->magic), be32_to_cpu(magic_guess)); + + /* + * If we're sure of the block's format, proceed with the salvage + * operation using the specified magic number. + */ + if (magic_guess) { + hdr->magic = magic_guess; + goto recover; + } + + /* + * If we couldn't guess what type of directory this is, then we will + * only salvage entries from directory blocks that match the magic + * number and pass verifiers. + */ + switch (hdr->magic) { + case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC): + case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC): + if (!xrep_buf_verify_struct(bp, &xfs_dir3_block_buf_ops)) + goto out; + if (xfs_dir3_block_header_check(bp, rd->sc->ip->i_ino) != NULL) + goto out; + break; + case cpu_to_be32(XFS_DIR2_DATA_MAGIC): + case cpu_to_be32(XFS_DIR3_DATA_MAGIC): + if (!xrep_buf_verify_struct(bp, &xfs_dir3_data_buf_ops)) + goto out; + if (xfs_dir3_data_header_check(bp, rd->sc->ip->i_ino) != NULL) + goto out; + break; + default: + goto out; + } + +recover: + error = xrep_dir_recover_data(rd, bp); + +out: + hdr->magic = oldmagic; + xfs_trans_brelse(rd->sc->tp, bp); + return error; +} + +static inline void +xrep_dir_init_args( + struct xrep_dir *rd, + struct xfs_inode *dp, + const struct xfs_name *name) +{ + memset(&rd->args, 0, sizeof(struct xfs_da_args)); + rd->args.geo = rd->sc->mp->m_dir_geo; + rd->args.whichfork = XFS_DATA_FORK; + rd->args.owner = rd->sc->ip->i_ino; + rd->args.trans = rd->sc->tp; + rd->args.dp = dp; + if (!name) + return; + rd->args.name = name->name; + rd->args.namelen = name->len; + rd->args.filetype = name->type; + rd->args.hashval = xfs_dir2_hashname(rd->sc->mp, name); +} + +/* Replay a stashed createname into the temporary directory. */ +STATIC int +xrep_dir_replay_createname( + struct xrep_dir *rd, + const struct xfs_name *name, + xfs_ino_t inum, + xfs_extlen_t total) +{ + struct xfs_scrub *sc = rd->sc; + struct xfs_inode *dp = rd->sc->tempip; + int error; + + ASSERT(S_ISDIR(VFS_I(dp)->i_mode)); + + error = xfs_dir_ino_validate(sc->mp, inum); + if (error) + return error; + + trace_xrep_dir_replay_createname(dp, name, inum); + + xrep_dir_init_args(rd, dp, name); + rd->args.inumber = inum; + rd->args.total = total; + rd->args.op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT; + return xfs_dir_createname_args(&rd->args); +} + +/* Replay a stashed removename onto the temporary directory. */ +STATIC int +xrep_dir_replay_removename( + struct xrep_dir *rd, + const struct xfs_name *name, + xfs_extlen_t total) +{ + struct xfs_inode *dp = rd->args.dp; + + ASSERT(S_ISDIR(VFS_I(dp)->i_mode)); + + xrep_dir_init_args(rd, dp, name); + rd->args.op_flags = 0; + rd->args.total = total; + + trace_xrep_dir_replay_removename(dp, name, 0); + return xfs_dir_removename_args(&rd->args); +} + +/* + * Add this stashed incore directory entry to the temporary directory. + * The caller must hold the tempdir's IOLOCK, must not hold any ILOCKs, and + * must not be in transaction context. + */ +STATIC int +xrep_dir_replay_update( + struct xrep_dir *rd, + const struct xfs_name *xname, + const struct xrep_dirent *dirent) +{ + struct xfs_mount *mp = rd->sc->mp; +#ifdef DEBUG + xfs_ino_t ino; +#endif + uint resblks; + int error; + + resblks = xfs_link_space_res(mp, xname->len); + error = xchk_trans_alloc(rd->sc, resblks); + if (error) + return error; + + /* Lock the temporary directory and join it to the transaction */ + xrep_tempfile_ilock(rd->sc); + xfs_trans_ijoin(rd->sc->tp, rd->sc->tempip, 0); + + switch (dirent->action) { + case XREP_DIRENT_ADD: + /* + * Create a replacement dirent in the temporary directory. + * Note that _createname doesn't check for existing entries. + * There shouldn't be any in the temporary dir, but we'll + * verify this in debug mode. + */ +#ifdef DEBUG + error = xchk_dir_lookup(rd->sc, rd->sc->tempip, xname, &ino); + if (error != -ENOENT) { + ASSERT(error != -ENOENT); + goto out_cancel; + } +#endif + + error = xrep_dir_replay_createname(rd, xname, dirent->ino, + resblks); + if (error) + goto out_cancel; + + if (xname->type == XFS_DIR3_FT_DIR) + rd->subdirs++; + rd->dirents++; + break; + case XREP_DIRENT_REMOVE: + /* + * Remove a dirent from the temporary directory. Note that + * _removename doesn't check the inode target of the exist + * entry. There should be a perfect match in the temporary + * dir, but we'll verify this in debug mode. + */ +#ifdef DEBUG + error = xchk_dir_lookup(rd->sc, rd->sc->tempip, xname, &ino); + if (error) { + ASSERT(error != 0); + goto out_cancel; + } + if (ino != dirent->ino) { + ASSERT(ino == dirent->ino); + error = -EIO; + goto out_cancel; + } +#endif + + error = xrep_dir_replay_removename(rd, xname, resblks); + if (error) + goto out_cancel; + + if (xname->type == XFS_DIR3_FT_DIR) + rd->subdirs--; + rd->dirents--; + break; + default: + ASSERT(0); + error = -EIO; + goto out_cancel; + } + + /* Commit and unlock. */ + error = xrep_trans_commit(rd->sc); + if (error) + return error; + + xrep_tempfile_iunlock(rd->sc); + return 0; +out_cancel: + xchk_trans_cancel(rd->sc); + xrep_tempfile_iunlock(rd->sc); + return error; +} + +/* + * Flush stashed incore dirent updates that have been recorded by the scanner. + * This is done to reduce the memory requirements of the directory rebuild, + * since directories can contain up to 32GB of directory data. + * + * Caller must not hold transactions or ILOCKs. Caller must hold the tempdir + * IOLOCK. + */ +STATIC int +xrep_dir_replay_updates( + struct xrep_dir *rd) +{ + xfarray_idx_t array_cur; + int error; + + /* Add all the salvaged dirents to the temporary directory. */ + mutex_lock(&rd->pscan.lock); + foreach_xfarray_idx(rd->dir_entries, array_cur) { + struct xrep_dirent dirent; + + error = xfarray_load(rd->dir_entries, array_cur, &dirent); + if (error) + goto out_unlock; + + error = xfblob_loadname(rd->dir_names, dirent.name_cookie, + &rd->xname, dirent.namelen); + if (error) + goto out_unlock; + rd->xname.type = dirent.ftype; + mutex_unlock(&rd->pscan.lock); + + error = xrep_dir_replay_update(rd, &rd->xname, &dirent); + if (error) + return error; + mutex_lock(&rd->pscan.lock); + } + + /* Empty out both arrays now that we've added the entries. */ + xfarray_truncate(rd->dir_entries); + xfblob_truncate(rd->dir_names); + mutex_unlock(&rd->pscan.lock); + return 0; +out_unlock: + mutex_unlock(&rd->pscan.lock); + return error; +} + +/* + * Periodically flush stashed directory entries to the temporary dir. This + * is done to reduce the memory requirements of the directory rebuild, since + * directories can contain up to 32GB of directory data. + */ +STATIC int +xrep_dir_flush_stashed( + struct xrep_dir *rd) +{ + int error; + + /* + * Entering this function, the scrub context has a reference to the + * inode being repaired, the temporary file, and a scrub transaction + * that we use during dirent salvaging to avoid livelocking if there + * are cycles in the directory structures. We hold ILOCK_EXCL on both + * the inode being repaired and the temporary file, though they are + * not ijoined to the scrub transaction. + * + * To constrain kernel memory use, we occasionally write salvaged + * dirents from the xfarray and xfblob structures into the temporary + * directory in preparation for exchanging the directory structures at + * the end. Updating the temporary file requires a transaction, so we + * commit the scrub transaction and drop the two ILOCKs so that + * we can allocate whatever transaction we want. + * + * We still hold IOLOCK_EXCL on the inode being repaired, which + * prevents anyone from accessing the damaged directory data while we + * repair it. + */ + error = xrep_trans_commit(rd->sc); + if (error) + return error; + xchk_iunlock(rd->sc, XFS_ILOCK_EXCL); + + /* + * Take the IOLOCK of the temporary file while we modify dirents. 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(rd->sc); + if (error) + return error; + + /* Write to the tempdir all the updates that we've stashed. */ + error = xrep_dir_replay_updates(rd); + xrep_tempfile_iounlock(rd->sc); + if (error) + return error; + + /* + * Recreate the salvage transaction and relock the dir we're salvaging. + */ + error = xchk_trans_alloc(rd->sc, 0); + if (error) + return error; + xchk_ilock(rd->sc, XFS_ILOCK_EXCL); + return 0; +} + +/* Decide if we've stashed too much dirent data in memory. */ +static inline bool +xrep_dir_want_flush_stashed( + struct xrep_dir *rd) +{ + unsigned long long bytes; + + bytes = xfarray_bytes(rd->dir_entries) + xfblob_bytes(rd->dir_names); + return bytes > XREP_DIR_MAX_STASH_BYTES; +} + +/* Extract as many directory entries as we can. */ +STATIC int +xrep_dir_recover( + struct xrep_dir *rd) +{ + struct xfs_bmbt_irec got; + struct xfs_scrub *sc = rd->sc; + struct xfs_da_geometry *geo = sc->mp->m_dir_geo; + xfs_fileoff_t offset; + xfs_dablk_t dabno; + __be32 magic_guess; + int nmap; + int error; + + xrep_dir_guess_format(rd, &magic_guess); + + /* Iterate each directory data block in the data fork. */ + for (offset = 0; + offset < geo->leafblk; + offset = got.br_startoff + got.br_blockcount) { + nmap = 1; + error = xfs_bmapi_read(sc->ip, offset, geo->leafblk - offset, + &got, &nmap, 0); + if (error) + return error; + if (nmap != 1) + return -EFSCORRUPTED; + if (!xfs_bmap_is_written_extent(&got)) + continue; + + for (dabno = round_up(got.br_startoff, geo->fsbcount); + dabno < got.br_startoff + got.br_blockcount; + dabno += geo->fsbcount) { + if (xchk_should_terminate(rd->sc, &error)) + return error; + + error = xrep_dir_recover_dirblock(rd, + magic_guess, dabno); + if (error) + return error; + + /* Flush dirents to constrain memory usage. */ + if (xrep_dir_want_flush_stashed(rd)) { + error = xrep_dir_flush_stashed(rd); + if (error) + return error; + } + } + } + + return 0; +} + +/* + * Find all the directory entries for this inode by scraping them out of the + * directory leaf blocks by hand, and flushing them into the temp dir. + */ +STATIC int +xrep_dir_find_entries( + struct xrep_dir *rd) +{ + struct xfs_inode *dp = rd->sc->ip; + int error; + + /* + * Salvage directory entries from the old directory, and write them to + * the temporary directory. + */ + if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL) { + error = xrep_dir_recover_sf(rd); + } else { + error = xfs_iread_extents(rd->sc->tp, dp, XFS_DATA_FORK); + if (error) + return error; + + error = xrep_dir_recover(rd); + } + if (error) + return error; + + return xrep_dir_flush_stashed(rd); +} + +/* Scan all files in the filesystem for dirents. */ +STATIC int +xrep_dir_salvage_entries( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + int error; + + /* + * Drop the ILOCK on this directory so that we can scan for this + * directory's parent. 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); + error = xrep_dir_find_parent(rd); + xchk_ilock(sc, XFS_ILOCK_EXCL); + if (error) + return error; + + /* + * Collect directory entries by parsing raw leaf blocks to salvage + * whatever we can. When we're done, free the staging memory before + * exchanging the directories to reduce memory usage. + */ + error = xrep_dir_find_entries(rd); + if (error) + return error; + + /* + * Cancel the repair transaction and drop the ILOCK so that we can + * (later) use the atomic mapping exchange functions to compute the + * correct block reservations and re-lock the inodes. + * + * We still hold IOLOCK_EXCL (aka i_rwsem) which will prevent directory + * modifications, but there's nothing to prevent userspace from reading + * the directory until we're ready for the exchange operation. Reads + * will return -EIO without shutting down the fs, so we're ok with + * that. + * + * The VFS can change dotdot on us, but the findparent scan will keep + * our incore parent inode up to date. See the note on locking issues + * for more details. + */ + error = xrep_trans_commit(sc); + if (error) + return error; + + xchk_iunlock(sc, XFS_ILOCK_EXCL); + return 0; +} + + +/* + * Examine a parent pointer of a file. If it leads us back to the directory + * that we're rebuilding, create an incore dirent from the parent pointer and + * stash it. + */ +STATIC int +xrep_dir_scan_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 xfs_name xname = { + .name = name, + .len = namelen, + .type = xfs_mode_to_ftype(VFS_I(ip)->i_mode), + }; + xfs_ino_t parent_ino; + uint32_t parent_gen; + struct xrep_dir *rd = priv; + int error; + + if (!(attr_flags & XFS_ATTR_PARENT)) + return 0; + + /* + * Ignore parent pointers that point back to a different dir, list the + * wrong generation number, or are invalid. + */ + error = xfs_parent_from_attr(sc->mp, attr_flags, name, namelen, value, + valuelen, &parent_ino, &parent_gen); + if (error) + return error; + + if (parent_ino != sc->ip->i_ino || + parent_gen != VFS_I(sc->ip)->i_generation) + return 0; + + mutex_lock(&rd->pscan.lock); + error = xrep_dir_stash_createname(rd, &xname, ip->i_ino); + mutex_unlock(&rd->pscan.lock); + return error; +} + +/* + * If this child dirent points to the directory being repaired, remember that + * fact so that we can reset the dotdot entry if necessary. + */ +STATIC int +xrep_dir_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_dir *rd = priv; + + /* Dirent doesn't point to this directory. */ + if (ino != rd->sc->ip->i_ino) + return 0; + + /* Ignore garbage inum. */ + if (!xfs_verify_dir_ino(rd->sc->mp, ino)) + return 0; + + /* No weird looking names. */ + if (name->len >= MAXNAMELEN || name->len <= 0) + return 0; + + /* 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; + + trace_xrep_dir_stash_createname(sc->tempip, &xfs_name_dotdot, + dp->i_ino); + + xrep_findparent_scan_found(&rd->pscan, dp->i_ino); + return 0; +} + +/* + * Decide if we want to look for child dirents or parent pointers in this file. + * Skip the dir being repaired and any files being used to stage repairs. + */ +static inline bool +xrep_dir_want_scan( + struct xrep_dir *rd, + const struct xfs_inode *ip) +{ + return ip != rd->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 or + * has an unloaded attr bmbt. Otherwise, take ILOCK_SHARED. + */ +static inline unsigned int +xrep_dir_scan_ilock( + struct xrep_dir *rd, + struct xfs_inode *ip) +{ + uint lock_mode = XFS_ILOCK_SHARED; + + /* Need to take the shared ILOCK to advance the iscan cursor. */ + if (!xrep_dir_want_scan(rd, 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; + } + + if (xfs_inode_has_attr_fork(ip) && xfs_need_iread_extents(&ip->i_af)) + lock_mode = XFS_ILOCK_EXCL; + +lock: + xfs_ilock(ip, lock_mode); + return lock_mode; +} + +/* + * Scan this file for relevant child dirents or parent pointers that point to + * the directory we're rebuilding. + */ +STATIC int +xrep_dir_scan_file( + struct xrep_dir *rd, + struct xfs_inode *ip) +{ + unsigned int lock_mode; + int error = 0; + + lock_mode = xrep_dir_scan_ilock(rd, ip); + + if (!xrep_dir_want_scan(rd, ip)) + goto scan_done; + + /* + * 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(ip)) { + error = -EBUSY; + goto scan_done; + } + + error = xchk_xattr_walk(rd->sc, ip, xrep_dir_scan_pptr, NULL, rd); + if (error) + 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(rd->sc, ip, xrep_dir_scan_dirent, rd); + if (error) + goto scan_done; + } + +scan_done: + xchk_iscan_mark_visited(&rd->pscan.iscan, ip); + xfs_iunlock(ip, lock_mode); + return error; +} + +/* + * Scan all files in the filesystem for parent pointers that we can turn into + * replacement dirents, and a dirent that we can use to set the dotdot pointer. + */ +STATIC int +xrep_dir_scan_dirtree( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + struct xfs_inode *ip; + int error; + + /* Roots of directory trees are their own parents. */ + if (sc->ip == sc->mp->m_rootip) + xrep_findparent_scan_found(&rd->pscan, sc->ip->i_ino); + + /* + * Filesystem scans are time consuming. Drop the directory 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 even though we've dropped the locks. + */ + 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(&rd->pscan.iscan, &ip)) == 1) { + bool flush; + + error = xrep_dir_scan_file(rd, ip); + xchk_irele(sc, ip); + if (error) + break; + + /* Flush stashed dirent updates to constrain memory usage. */ + mutex_lock(&rd->pscan.lock); + flush = xrep_dir_want_flush_stashed(rd); + mutex_unlock(&rd->pscan.lock); + if (flush) { + xchk_trans_cancel(sc); + + error = xrep_tempfile_iolock_polled(sc); + if (error) + break; + + error = xrep_dir_replay_updates(rd); + 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(&rd->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; + } + + /* + * Cancel the empty transaction so that we can (later) use the atomic + * file mapping exchange functions to lock files and commit the new + * directory. + */ + xchk_trans_cancel(rd->sc); + return 0; +} + +/* + * Capture dirent updates being made by other threads which are relevant to the + * directory being repaired. + */ +STATIC int +xrep_dir_live_update( + struct notifier_block *nb, + unsigned long action, + void *data) +{ + struct xfs_dir_update_params *p = data; + struct xrep_dir *rd; + struct xfs_scrub *sc; + int error = 0; + + rd = container_of(nb, struct xrep_dir, pscan.dhook.dirent_hook.nb); + sc = rd->sc; + + /* + * This thread updated a child dirent in the directory that we're + * rebuilding. Stash the update for replay against the temporary + * directory. + */ + if (p->dp->i_ino == sc->ip->i_ino && + xchk_iscan_want_live_update(&rd->pscan.iscan, p->ip->i_ino)) { + mutex_lock(&rd->pscan.lock); + if (p->delta > 0) + error = xrep_dir_stash_createname(rd, p->name, + p->ip->i_ino); + else + error = xrep_dir_stash_removename(rd, p->name, + p->ip->i_ino); + mutex_unlock(&rd->pscan.lock); + if (error) + goto out_abort; + } + + /* + * This thread updated another directory's child dirent that points to + * the directory that we're rebuilding, so remember the new dotdot + * target. + */ + if (p->ip->i_ino == sc->ip->i_ino && + xchk_iscan_want_live_update(&rd->pscan.iscan, p->dp->i_ino)) { + if (p->delta > 0) { + trace_xrep_dir_stash_createname(sc->tempip, + &xfs_name_dotdot, + p->dp->i_ino); + + xrep_findparent_scan_found(&rd->pscan, p->dp->i_ino); + } else { + trace_xrep_dir_stash_removename(sc->tempip, + &xfs_name_dotdot, + rd->pscan.parent_ino); + + xrep_findparent_scan_found(&rd->pscan, NULLFSINO); + } + } + + return NOTIFY_DONE; +out_abort: + xchk_iscan_abort(&rd->pscan.iscan); + return NOTIFY_DONE; +} + +/* + * Free all the directory blocks and reset the data fork. The caller must + * join the inode to the transaction. This function returns with the inode + * joined to a clean scrub transaction. + */ +STATIC int +xrep_dir_reset_fork( + struct xrep_dir *rd, + xfs_ino_t parent_ino) +{ + struct xfs_scrub *sc = rd->sc; + struct xfs_ifork *ifp = xfs_ifork_ptr(sc->tempip, XFS_DATA_FORK); + int error; + + /* Unmap all the directory buffers. */ + if (xfs_ifork_has_extents(ifp)) { + error = xrep_reap_ifork(sc, sc->tempip, XFS_DATA_FORK); + if (error) + return error; + } + + trace_xrep_dir_reset_fork(sc->tempip, parent_ino); + + /* Reset the data fork to an empty data fork. */ + xfs_idestroy_fork(ifp); + ifp->if_bytes = 0; + sc->tempip->i_disk_size = 0; + + /* Reinitialize the short form directory. */ + xrep_dir_init_args(rd, sc->tempip, NULL); + return xfs_dir2_sf_create(&rd->args, parent_ino); +} + +/* + * Prepare both inodes' directory forks for exchanging mappings. Promote the + * tempfile from short format to leaf format, and if the file being repaired + * has a short format data fork, turn it into an empty extent list. + */ +STATIC int +xrep_dir_swap_prep( + struct xfs_scrub *sc, + bool temp_local, + bool ip_local) +{ + int error; + + /* + * If the tempfile's directory is in shortform format, convert that to + * a single leaf extent so that we can use the atomic mapping exchange. + */ + if (temp_local) { + struct xfs_da_args args = { + .dp = sc->tempip, + .geo = sc->mp->m_dir_geo, + .whichfork = XFS_DATA_FORK, + .trans = sc->tp, + .total = 1, + .owner = sc->ip->i_ino, + }; + + error = xfs_dir2_sf_to_block(&args); + if (error) + return error; + + /* + * Roll the deferred log items to get us back to a clean + * transaction. + */ + error = xfs_defer_finish(&sc->tp); + if (error) + return error; + } + + /* + * If the file being repaired had a shortform data fork, convert that + * to an empty extent list in preparation for the atomic mapping + * exchange. + */ + if (ip_local) { + struct xfs_ifork *ifp; + + ifp = xfs_ifork_ptr(sc->ip, XFS_DATA_FORK); + xfs_idestroy_fork(ifp); + ifp->if_format = XFS_DINODE_FMT_EXTENTS; + ifp->if_nextents = 0; + ifp->if_bytes = 0; + ifp->if_data = NULL; + ifp->if_height = 0; + + xfs_trans_log_inode(sc->tp, sc->ip, + XFS_ILOG_CORE | XFS_ILOG_DDATA); + } + + return 0; +} + +/* + * Replace the inode number of a directory entry. + */ +static int +xrep_dir_replace( + struct xrep_dir *rd, + struct xfs_inode *dp, + const struct xfs_name *name, + xfs_ino_t inum, + xfs_extlen_t total) +{ + struct xfs_scrub *sc = rd->sc; + int error; + + ASSERT(S_ISDIR(VFS_I(dp)->i_mode)); + + error = xfs_dir_ino_validate(sc->mp, inum); + if (error) + return error; + + xrep_dir_init_args(rd, dp, name); + rd->args.inumber = inum; + rd->args.total = total; + return xfs_dir_replace_args(&rd->args); +} + +/* + * Reset the link count of this directory and adjust the unlinked list pointers + * as needed. + */ +STATIC int +xrep_dir_set_nlink( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + struct xfs_inode *dp = sc->ip; + struct xfs_perag *pag; + unsigned int new_nlink = min_t(unsigned long long, + rd->subdirs + 2, + XFS_NLINK_PINNED); + int error; + + /* + * The directory is not on the incore unlinked list, which means that + * it needs to be reachable via the directory tree. Update the nlink + * with our observed link count. If the directory has no parent, it + * will be moved to the orphanage. + */ + if (!xfs_inode_on_unlinked_list(dp)) + goto reset_nlink; + + /* + * The directory is on the unlinked list and we did not find any + * dirents. Set the link count to zero and let the directory + * inactivate when the last reference drops. + */ + if (rd->dirents == 0) { + rd->needs_adoption = false; + new_nlink = 0; + goto reset_nlink; + } + + /* + * The directory is on the unlinked list and we found dirents. This + * directory needs to be reachable via the directory tree. Remove the + * dir from the unlinked list and update nlink with the observed link + * count. If the directory has no parent, it will be moved to the + * orphanage. + */ + pag = xfs_perag_get(sc->mp, XFS_INO_TO_AGNO(sc->mp, dp->i_ino)); + if (!pag) { + ASSERT(0); + return -EFSCORRUPTED; + } + + error = xfs_iunlink_remove(sc->tp, pag, dp); + xfs_perag_put(pag); + if (error) + return error; + +reset_nlink: + if (VFS_I(dp)->i_nlink != new_nlink) + set_nlink(VFS_I(dp), new_nlink); + return 0; +} + +/* + * Finish replaying stashed dirent updates, allocate a transaction for + * exchanging data fork mappings, and take the ILOCKs of both directories + * before we commit the new directory structure. + */ +STATIC int +xrep_dir_finalize_tempdir( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + int error; + + if (!xfs_has_parent(sc->mp)) + return xrep_tempexch_trans_alloc(sc, XFS_DATA_FORK, &rd->tx); + + /* + * Repair relies on the ILOCK to quiesce all possible dirent updates. + * Replay all queued dirent updates into the tempdir before exchanging + * the contents, even if that means dropping the ILOCKs and the + * transaction. + */ + do { + error = xrep_dir_replay_updates(rd); + if (error) + return error; + + error = xrep_tempexch_trans_alloc(sc, XFS_DATA_FORK, &rd->tx); + if (error) + return error; + + if (xfarray_length(rd->dir_entries) == 0) + break; + + xchk_trans_cancel(sc); + xrep_tempfile_iunlock_both(sc); + } while (!xchk_should_terminate(sc, &error)); + return error; +} + +/* Exchange the temporary directory's data fork with the one being repaired. */ +STATIC int +xrep_dir_swap( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + bool ip_local, temp_local; + int error = 0; + + /* + * If we never found the parent for this directory, temporarily assign + * the root dir as the parent; we'll move this to the orphanage after + * exchanging the dir contents. We hold the ILOCK of the dir being + * repaired, so we're not worried about racy updates of dotdot. + */ + ASSERT(sc->ilock_flags & XFS_ILOCK_EXCL); + if (rd->pscan.parent_ino == NULLFSINO) { + rd->needs_adoption = true; + rd->pscan.parent_ino = rd->sc->mp->m_sb.sb_rootino; + } + + /* + * Reset the temporary directory's '..' entry to point to the parent + * that we found. The temporary directory was created with the root + * directory as the parent, so we can skip this if repairing a + * subdirectory of the root. + * + * It's also possible that this replacement could also expand a sf + * tempdir into block format. + */ + if (rd->pscan.parent_ino != sc->mp->m_rootip->i_ino) { + error = xrep_dir_replace(rd, rd->sc->tempip, &xfs_name_dotdot, + rd->pscan.parent_ino, rd->tx.req.resblks); + if (error) + return error; + } + + /* + * Changing the dot and dotdot entries could have changed the shape of + * the directory, so we recompute these. + */ + ip_local = sc->ip->i_df.if_format == XFS_DINODE_FMT_LOCAL; + temp_local = sc->tempip->i_df.if_format == XFS_DINODE_FMT_LOCAL; + + /* + * If the both files have a local format data fork and the rebuilt + * directory data would fit in the repaired file's data fork, copy + * the contents from the tempfile and update the directory link count. + * We're done now. + */ + if (ip_local && temp_local && + sc->tempip->i_disk_size <= xfs_inode_data_fork_size(sc->ip)) { + xrep_tempfile_copyout_local(sc, XFS_DATA_FORK); + return xrep_dir_set_nlink(rd); + } + + /* + * Clean the transaction before we start working on exchanging + * directory contents. + */ + error = xrep_tempfile_roll_trans(rd->sc); + if (error) + return error; + + /* Otherwise, make sure both data forks are in block-mapping mode. */ + error = xrep_dir_swap_prep(sc, temp_local, ip_local); + if (error) + return error; + + /* + * Set nlink of the directory in the same transaction sequence that + * (atomically) commits the new directory data. + */ + error = xrep_dir_set_nlink(rd); + if (error) + return error; + + return xrep_tempexch_contents(sc, &rd->tx); +} + +/* + * Exchange the new directory contents (which we created in the tempfile) with + * the directory being repaired. + */ +STATIC int +xrep_dir_rebuild_tree( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + int error; + + trace_xrep_dir_rebuild_tree(sc->ip, rd->pscan.parent_ino); + + /* + * Take the IOLOCK on the temporary file so that we can run dir + * operations with the same locks held as we would for a normal file. + * We still hold sc->ip's IOLOCK. + */ + error = xrep_tempfile_iolock_polled(rd->sc); + if (error) + return error; + + /* + * Allocate transaction, lock inodes, and make sure that we've replayed + * all the stashed dirent updates to the tempdir. After this point, + * we're ready to exchange data fork mappings. + */ + error = xrep_dir_finalize_tempdir(rd); + if (error) + return error; + + if (xchk_iscan_aborted(&rd->pscan.iscan)) + return -ECANCELED; + + /* + * Exchange the tempdir's data fork with the file being repaired. This + * recreates the transaction and re-takes the ILOCK in the scrub + * context. + */ + error = xrep_dir_swap(rd); + if (error) + return error; + + /* + * Release the old directory blocks and reset the data fork of the temp + * directory to an empty shortform directory because inactivation does + * nothing for directories. + */ + error = xrep_dir_reset_fork(rd, sc->mp->m_rootip->i_ino); + 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 directory. + */ + error = xfs_trans_roll(&sc->tp); + if (error) + return error; + + xrep_tempfile_iunlock(sc); + xrep_tempfile_iounlock(sc); + return 0; +} + +/* Set up the filesystem scan so we can regenerate directory entries. */ +STATIC int +xrep_dir_setup_scan( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + char *descr; + int error; + + /* Set up some staging memory for salvaging dirents. */ + descr = xchk_xfile_ino_descr(sc, "directory entries"); + error = xfarray_create(descr, 0, sizeof(struct xrep_dirent), + &rd->dir_entries); + kfree(descr); + if (error) + return error; + + descr = xchk_xfile_ino_descr(sc, "directory entry names"); + error = xfblob_create(descr, &rd->dir_names); + kfree(descr); + if (error) + goto out_xfarray; + + if (xfs_has_parent(sc->mp)) + error = __xrep_findparent_scan_start(sc, &rd->pscan, + xrep_dir_live_update); + else + error = xrep_findparent_scan_start(sc, &rd->pscan); + if (error) + goto out_xfblob; + + return 0; + +out_xfblob: + xfblob_destroy(rd->dir_names); + rd->dir_names = NULL; +out_xfarray: + xfarray_destroy(rd->dir_entries); + rd->dir_entries = NULL; + return error; +} + +/* + * 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_dir_move_to_orphanage( + struct xrep_dir *rd) +{ + struct xfs_scrub *sc = rd->sc; + xfs_ino_t orig_parent, new_parent; + int error; + + /* + * 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; + + /* + * 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, &rd->adoption); + if (error) + return error; + + error = xrep_adoption_compute_name(&rd->adoption, &rd->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. + */ + error = xchk_dir_lookup(sc, sc->ip, &xfs_name_dotdot, &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(&rd->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(&rd->adoption); + if (error) + return error; + + xrep_orphanage_iunlock(sc, XFS_ILOCK_EXCL); + xrep_orphanage_iunlock(sc, XFS_IOLOCK_EXCL); + return 0; +} + +/* + * Repair the directory metadata. + * + * XXX: Directory entry buffers can be multiple fsblocks in size. The buffer + * cache in XFS can't handle aliased multiblock buffers, so this might + * misbehave if the directory blocks are crosslinked with other filesystem + * metadata. + * + * XXX: Is it necessary to check the dcache for this directory to make sure + * that we always recreate every cached entry? + */ +int +xrep_directory( + struct xfs_scrub *sc) +{ + struct xrep_dir *rd = sc->buf; + int error; + + /* The rmapbt is required to reap the old data fork. */ + if (!xfs_has_rmapbt(sc->mp)) + return -EOPNOTSUPP; + /* We require atomic file exchange range to rebuild anything. */ + if (!xfs_has_exchange_range(sc->mp)) + return -EOPNOTSUPP; + + error = xrep_dir_setup_scan(rd); + if (error) + return error; + + if (xfs_has_parent(sc->mp)) + error = xrep_dir_scan_dirtree(rd); + else + error = xrep_dir_salvage_entries(rd); + if (error) + goto out_teardown; + + /* Last chance to abort before we start committing fixes. */ + if (xchk_should_terminate(sc, &error)) + goto out_teardown; + + error = xrep_dir_rebuild_tree(rd); + if (error) + goto out_teardown; + + if (rd->needs_adoption) { + if (!xrep_orphanage_can_adopt(rd->sc)) + error = -EFSCORRUPTED; + else + error = xrep_dir_move_to_orphanage(rd); + if (error) + goto out_teardown; + } + +out_teardown: + xrep_dir_teardown(sc); + return error; +} |