diff options
Diffstat (limited to 'fs/bcachefs/str_hash.c')
| -rw-r--r-- | fs/bcachefs/str_hash.c | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/fs/bcachefs/str_hash.c b/fs/bcachefs/str_hash.c new file mode 100644 index 000000000000..0cbf5508a32c --- /dev/null +++ b/fs/bcachefs/str_hash.c @@ -0,0 +1,328 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "bcachefs.h" +#include "btree_cache.h" +#include "btree_update.h" +#include "dirent.h" +#include "fsck.h" +#include "str_hash.h" +#include "subvolume.h" + +static int bch2_dirent_has_target(struct btree_trans *trans, struct bkey_s_c_dirent d) +{ + if (d.v->d_type == DT_SUBVOL) { + struct bch_subvolume subvol; + int ret = bch2_subvolume_get(trans, le32_to_cpu(d.v->d_child_subvol), + false, &subvol); + if (ret && !bch2_err_matches(ret, ENOENT)) + return ret; + return !ret; + } else { + struct btree_iter iter; + struct bkey_s_c k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_inodes, + SPOS(0, le64_to_cpu(d.v->d_inum), d.k->p.snapshot), 0); + int ret = bkey_err(k); + if (ret) + return ret; + + ret = bkey_is_inode(k.k); + bch2_trans_iter_exit(trans, &iter); + return ret; + } +} + +static noinline int fsck_rename_dirent(struct btree_trans *trans, + struct snapshots_seen *s, + const struct bch_hash_desc desc, + struct bch_hash_info *hash_info, + struct bkey_s_c_dirent old) +{ + struct qstr old_name = bch2_dirent_get_name(old); + struct bkey_i_dirent *new = bch2_trans_kmalloc(trans, bkey_bytes(old.k) + 32); + int ret = PTR_ERR_OR_ZERO(new); + if (ret) + return ret; + + bkey_dirent_init(&new->k_i); + dirent_copy_target(new, old); + new->k.p = old.k->p; + + for (unsigned i = 0; i < 1000; i++) { + unsigned len = sprintf(new->v.d_name, "%.*s.fsck_renamed-%u", + old_name.len, old_name.name, i); + unsigned u64s = BKEY_U64s + dirent_val_u64s(len, 0); + + if (u64s > U8_MAX) + return -EINVAL; + + new->k.u64s = u64s; + + ret = bch2_hash_set_in_snapshot(trans, bch2_dirent_hash_desc, hash_info, + (subvol_inum) { 0, old.k->p.inode }, + old.k->p.snapshot, &new->k_i, + BTREE_UPDATE_internal_snapshot_node); + if (!bch2_err_matches(ret, EEXIST)) + break; + } + + if (ret) + return ret; + + return bch2_fsck_update_backpointers(trans, s, desc, hash_info, &new->k_i); +} + +static noinline int hash_pick_winner(struct btree_trans *trans, + const struct bch_hash_desc desc, + struct bch_hash_info *hash_info, + struct bkey_s_c k1, + struct bkey_s_c k2) +{ + if (bkey_val_bytes(k1.k) == bkey_val_bytes(k2.k) && + !memcmp(k1.v, k2.v, bkey_val_bytes(k1.k))) + return 0; + + switch (desc.btree_id) { + case BTREE_ID_dirents: { + int ret = bch2_dirent_has_target(trans, bkey_s_c_to_dirent(k1)); + if (ret < 0) + return ret; + if (!ret) + return 0; + + ret = bch2_dirent_has_target(trans, bkey_s_c_to_dirent(k2)); + if (ret < 0) + return ret; + if (!ret) + return 1; + return 2; + } + default: + return 0; + } +} + +/* + * str_hash lookups across snapshots break in wild ways if hash_info in + * different snapshot versions doesn't match - so if we find one mismatch, check + * them all + */ +int bch2_repair_inode_hash_info(struct btree_trans *trans, + struct bch_inode_unpacked *snapshot_root) +{ + struct bch_fs *c = trans->c; + struct btree_iter iter; + struct bkey_s_c k; + struct printbuf buf = PRINTBUF; + bool need_commit = false; + int ret = 0; + + for_each_btree_key_norestart(trans, iter, BTREE_ID_inodes, + POS(0, snapshot_root->bi_inum), + BTREE_ITER_all_snapshots, k, ret) { + if (bpos_ge(k.k->p, SPOS(0, snapshot_root->bi_inum, snapshot_root->bi_snapshot))) + break; + if (!bkey_is_inode(k.k)) + continue; + + struct bch_inode_unpacked inode; + ret = bch2_inode_unpack(k, &inode); + if (ret) + break; + + if (inode.bi_hash_seed == snapshot_root->bi_hash_seed && + INODE_STR_HASH(&inode) == INODE_STR_HASH(snapshot_root)) { +#ifdef CONFIG_BCACHEFS_DEBUG + struct bch_hash_info hash1 = bch2_hash_info_init(c, snapshot_root); + struct bch_hash_info hash2 = bch2_hash_info_init(c, &inode); + + BUG_ON(hash1.type != hash2.type || + memcmp(&hash1.siphash_key, + &hash2.siphash_key, + sizeof(hash1.siphash_key))); +#endif + continue; + } + + printbuf_reset(&buf); + prt_printf(&buf, "inode %llu hash info in snapshots %u %u don't match\n", + snapshot_root->bi_inum, + inode.bi_snapshot, + snapshot_root->bi_snapshot); + + bch2_prt_str_hash_type(&buf, INODE_STR_HASH(&inode)); + prt_printf(&buf, " %llx\n", inode.bi_hash_seed); + + bch2_prt_str_hash_type(&buf, INODE_STR_HASH(snapshot_root)); + prt_printf(&buf, " %llx", snapshot_root->bi_hash_seed); + + if (fsck_err(trans, inode_snapshot_mismatch, "%s", buf.buf)) { + inode.bi_hash_seed = snapshot_root->bi_hash_seed; + SET_INODE_STR_HASH(&inode, INODE_STR_HASH(snapshot_root)); + + ret = __bch2_fsck_write_inode(trans, &inode); + if (ret) + break; + need_commit = true; + } + } + + if (ret) + goto err; + + if (!need_commit) { + struct printbuf buf = PRINTBUF; + bch2_log_msg_start(c, &buf); + + prt_printf(&buf, "inode %llu hash info mismatch with root, but mismatch not found\n", + snapshot_root->bi_inum); + + prt_printf(&buf, "root snapshot %u ", snapshot_root->bi_snapshot); + bch2_prt_str_hash_type(&buf, INODE_STR_HASH(snapshot_root)); + prt_printf(&buf, " %llx\n", snapshot_root->bi_hash_seed); +#if 0 + prt_printf(&buf, "vs snapshot %u ", hash_info->inum_snapshot); + bch2_prt_str_hash_type(&buf, hash_info->type); + prt_printf(&buf, " %llx %llx", hash_info->siphash_key.k0, hash_info->siphash_key.k1); +#endif + bch2_print_str(c, KERN_ERR, buf.buf); + printbuf_exit(&buf); + ret = -BCH_ERR_fsck_repair_unimplemented; + goto err; + } + + ret = bch2_trans_commit(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc) ?: + -BCH_ERR_transaction_restart_nested; +err: +fsck_err: + printbuf_exit(&buf); + bch2_trans_iter_exit(trans, &iter); + return ret; +} + +/* + * All versions of the same inode in different snapshots must have the same hash + * seed/type: verify that the hash info we're using matches the root + */ +static noinline int check_inode_hash_info_matches_root(struct btree_trans *trans, u64 inum, + struct bch_hash_info *hash_info) +{ + struct bch_inode_unpacked snapshot_root; + int ret = bch2_inode_find_snapshot_root(trans, inum, &snapshot_root); + if (ret) + return ret; + + struct bch_hash_info hash_root = bch2_hash_info_init(trans->c, &snapshot_root); + if (hash_info->type != hash_root.type || + memcmp(&hash_info->siphash_key, + &hash_root.siphash_key, + sizeof(hash_root.siphash_key))) + ret = bch2_repair_inode_hash_info(trans, &snapshot_root); + + return ret; +} + +int __bch2_str_hash_check_key(struct btree_trans *trans, + struct snapshots_seen *s, + const struct bch_hash_desc *desc, + struct bch_hash_info *hash_info, + struct btree_iter *k_iter, struct bkey_s_c hash_k) +{ + struct bch_fs *c = trans->c; + struct btree_iter iter = {}; + struct printbuf buf = PRINTBUF; + struct bkey_s_c k; + int ret = 0; + + u64 hash = desc->hash_bkey(hash_info, hash_k); + if (hash_k.k->p.offset < hash) + goto bad_hash; + + for_each_btree_key_norestart(trans, iter, desc->btree_id, + SPOS(hash_k.k->p.inode, hash, hash_k.k->p.snapshot), + BTREE_ITER_slots, k, ret) { + if (bkey_eq(k.k->p, hash_k.k->p)) + break; + + if (k.k->type == desc->key_type && + !desc->cmp_bkey(k, hash_k)) + goto duplicate_entries; + + if (bkey_deleted(k.k)) { + bch2_trans_iter_exit(trans, &iter); + goto bad_hash; + } + } +out: + bch2_trans_iter_exit(trans, &iter); + printbuf_exit(&buf); + return ret; +bad_hash: + /* + * Before doing any repair, check hash_info itself: + */ + ret = check_inode_hash_info_matches_root(trans, hash_k.k->p.inode, hash_info); + if (ret) + goto out; + + if (fsck_err(trans, hash_table_key_wrong_offset, + "hash table key at wrong offset: btree %s inode %llu offset %llu, hashed to %llu\n%s", + bch2_btree_id_str(desc->btree_id), hash_k.k->p.inode, hash_k.k->p.offset, hash, + (printbuf_reset(&buf), + bch2_bkey_val_to_text(&buf, c, hash_k), buf.buf))) { + struct bkey_i *new = bch2_bkey_make_mut_noupdate(trans, hash_k); + if (IS_ERR(new)) + return PTR_ERR(new); + + k = bch2_hash_set_or_get_in_snapshot(trans, &iter, *desc, hash_info, + (subvol_inum) { 0, hash_k.k->p.inode }, + hash_k.k->p.snapshot, new, + STR_HASH_must_create| + BTREE_ITER_with_updates| + BTREE_UPDATE_internal_snapshot_node); + ret = bkey_err(k); + if (ret) + goto out; + if (k.k) + goto duplicate_entries; + + ret = bch2_hash_delete_at(trans, *desc, hash_info, k_iter, + BTREE_UPDATE_internal_snapshot_node) ?: + bch2_fsck_update_backpointers(trans, s, *desc, hash_info, new) ?: + bch2_trans_commit(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc) ?: + -BCH_ERR_transaction_restart_nested; + goto out; + } +fsck_err: + goto out; +duplicate_entries: + ret = hash_pick_winner(trans, *desc, hash_info, hash_k, k); + if (ret < 0) + goto out; + + if (!fsck_err(trans, hash_table_key_duplicate, + "duplicate hash table keys%s:\n%s", + ret != 2 ? "" : ", both point to valid inodes", + (printbuf_reset(&buf), + bch2_bkey_val_to_text(&buf, c, hash_k), + prt_newline(&buf), + bch2_bkey_val_to_text(&buf, c, k), + buf.buf))) + goto out; + + switch (ret) { + case 0: + ret = bch2_hash_delete_at(trans, *desc, hash_info, k_iter, 0); + break; + case 1: + ret = bch2_hash_delete_at(trans, *desc, hash_info, &iter, 0); + break; + case 2: + ret = fsck_rename_dirent(trans, s, *desc, hash_info, bkey_s_c_to_dirent(hash_k)) ?: + bch2_hash_delete_at(trans, *desc, hash_info, k_iter, 0); + goto out; + } + + ret = bch2_trans_commit(trans, NULL, NULL, 0) ?: + -BCH_ERR_transaction_restart_nested; + goto out; +} |