// SPDX-License-Identifier: GPL-2.0 #include "bcachefs.h" #include "bkey_buf.h" #include "bkey_methods.h" #include "btree_update.h" #include "extents.h" #include "dirent.h" #include "fs.h" #include "keylist.h" #include "str_hash.h" #include "subvolume.h" #include static unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d) { unsigned bkey_u64s = bkey_val_u64s(d.k); unsigned bkey_bytes = bkey_u64s * sizeof(u64); u64 last_u64 = ((u64*)d.v)[bkey_u64s - 1]; #if CPU_BIG_ENDIAN unsigned trailing_nuls = last_u64 ? __builtin_ctzll(last_u64) / 8 : 64 / 8; #else unsigned trailing_nuls = last_u64 ? __builtin_clzll(last_u64) / 8 : 64 / 8; #endif return bkey_bytes - offsetof(struct bch_dirent, d_name) - trailing_nuls; } struct qstr bch2_dirent_get_name(struct bkey_s_c_dirent d) { return (struct qstr) QSTR_INIT(d.v->d_name, bch2_dirent_name_bytes(d)); } static u64 bch2_dirent_hash(const struct bch_hash_info *info, const struct qstr *name) { struct bch_str_hash_ctx ctx; bch2_str_hash_init(&ctx, info); bch2_str_hash_update(&ctx, info, name->name, name->len); /* [0,2) reserved for dots */ return max_t(u64, bch2_str_hash_end(&ctx, info), 2); } static u64 dirent_hash_key(const struct bch_hash_info *info, const void *key) { return bch2_dirent_hash(info, key); } static u64 dirent_hash_bkey(const struct bch_hash_info *info, struct bkey_s_c k) { struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k); struct qstr name = bch2_dirent_get_name(d); return bch2_dirent_hash(info, &name); } static bool dirent_cmp_key(struct bkey_s_c _l, const void *_r) { struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l); const struct qstr l_name = bch2_dirent_get_name(l); const struct qstr *r_name = _r; return !qstr_eq(l_name, *r_name); } static bool dirent_cmp_bkey(struct bkey_s_c _l, struct bkey_s_c _r) { struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l); struct bkey_s_c_dirent r = bkey_s_c_to_dirent(_r); const struct qstr l_name = bch2_dirent_get_name(l); const struct qstr r_name = bch2_dirent_get_name(r); return !qstr_eq(l_name, r_name); } static bool dirent_is_visible(subvol_inum inum, struct bkey_s_c k) { struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k); if (d.v->d_type == DT_SUBVOL) return le32_to_cpu(d.v->d_parent_subvol) == inum.subvol; return true; } const struct bch_hash_desc bch2_dirent_hash_desc = { .btree_id = BTREE_ID_dirents, .key_type = KEY_TYPE_dirent, .hash_key = dirent_hash_key, .hash_bkey = dirent_hash_bkey, .cmp_key = dirent_cmp_key, .cmp_bkey = dirent_cmp_bkey, .is_visible = dirent_is_visible, }; int bch2_dirent_invalid(struct bch_fs *c, struct bkey_s_c k, enum bkey_invalid_flags flags, struct printbuf *err) { struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k); struct qstr d_name = bch2_dirent_get_name(d); int ret = 0; bkey_fsck_err_on(!d_name.len, c, err, dirent_empty_name, "empty name"); bkey_fsck_err_on(bkey_val_u64s(k.k) > dirent_val_u64s(d_name.len), c, err, dirent_val_too_big, "value too big (%zu > %u)", bkey_val_u64s(k.k), dirent_val_u64s(d_name.len)); /* * Check new keys don't exceed the max length * (older keys may be larger.) */ bkey_fsck_err_on((flags & BKEY_INVALID_COMMIT) && d_name.len > BCH_NAME_MAX, c, err, dirent_name_too_long, "dirent name too big (%u > %u)", d_name.len, BCH_NAME_MAX); bkey_fsck_err_on(d_name.len != strnlen(d_name.name, d_name.len), c, err, dirent_name_embedded_nul, "dirent has stray data after name's NUL"); bkey_fsck_err_on((d_name.len == 1 && !memcmp(d_name.name, ".", 1)) || (d_name.len == 2 && !memcmp(d_name.name, "..", 2)), c, err, dirent_name_dot_or_dotdot, "invalid name"); bkey_fsck_err_on(memchr(d_name.name, '/', d_name.len), c, err, dirent_name_has_slash, "name with /"); bkey_fsck_err_on(d.v->d_type != DT_SUBVOL && le64_to_cpu(d.v->d_inum) == d.k->p.inode, c, err, dirent_to_itself, "dirent points to own directory"); fsck_err: return ret; } void bch2_dirent_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c k) { struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k); struct qstr d_name = bch2_dirent_get_name(d); prt_printf(out, "%.*s -> ", d_name.len, d_name.name); if (d.v->d_type != DT_SUBVOL) prt_printf(out, "%llu", le64_to_cpu(d.v->d_inum)); else prt_printf(out, "%u -> %u", le32_to_cpu(d.v->d_parent_subvol), le32_to_cpu(d.v->d_child_subvol)); prt_printf(out, " type %s", bch2_d_type_str(d.v->d_type)); } static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans, subvol_inum dir, u8 type, const struct qstr *name, u64 dst) { struct bkey_i_dirent *dirent; unsigned u64s = BKEY_U64s + dirent_val_u64s(name->len); if (name->len > BCH_NAME_MAX) return ERR_PTR(-ENAMETOOLONG); BUG_ON(u64s > U8_MAX); dirent = bch2_trans_kmalloc(trans, u64s * sizeof(u64)); if (IS_ERR(dirent)) return dirent; bkey_dirent_init(&dirent->k_i); dirent->k.u64s = u64s; if (type != DT_SUBVOL) { dirent->v.d_inum = cpu_to_le64(dst); } else { dirent->v.d_parent_subvol = cpu_to_le32(dir.subvol); dirent->v.d_child_subvol = cpu_to_le32(dst); } dirent->v.d_type = type; memcpy(dirent->v.d_name, name->name, name->len); memset(dirent->v.d_name + name->len, 0, bkey_val_bytes(&dirent->k) - offsetof(struct bch_dirent, d_name) - name->len); EBUG_ON(bch2_dirent_name_bytes(dirent_i_to_s_c(dirent)) != name->len); return dirent; } int bch2_dirent_create_snapshot(struct btree_trans *trans, u32 dir_subvol, u64 dir, u32 snapshot, const struct bch_hash_info *hash_info, u8 type, const struct qstr *name, u64 dst_inum, u64 *dir_offset, enum btree_iter_update_trigger_flags flags) { subvol_inum dir_inum = { .subvol = dir_subvol, .inum = dir }; struct bkey_i_dirent *dirent; int ret; dirent = dirent_create_key(trans, dir_inum, type, name, dst_inum); ret = PTR_ERR_OR_ZERO(dirent); if (ret) return ret; dirent->k.p.inode = dir; dirent->k.p.snapshot = snapshot; ret = bch2_hash_set_in_snapshot(trans, bch2_dirent_hash_desc, hash_info, dir_inum, snapshot, &dirent->k_i, flags|BTREE_UPDATE_internal_snapshot_node); *dir_offset = dirent->k.p.offset; return ret; } int bch2_dirent_create(struct btree_trans *trans, subvol_inum dir, const struct bch_hash_info *hash_info, u8 type, const struct qstr *name, u64 dst_inum, u64 *dir_offset, enum btree_iter_update_trigger_flags flags) { struct bkey_i_dirent *dirent; int ret; dirent = dirent_create_key(trans, dir, type, name, dst_inum); ret = PTR_ERR_OR_ZERO(dirent); if (ret) return ret; ret = bch2_hash_set(trans, bch2_dirent_hash_desc, hash_info, dir, &dirent->k_i, flags); *dir_offset = dirent->k.p.offset; return ret; } static void dirent_copy_target(struct bkey_i_dirent *dst, struct bkey_s_c_dirent src) { dst->v.d_inum = src.v->d_inum; dst->v.d_type = src.v->d_type; } int bch2_dirent_read_target(struct btree_trans *trans, subvol_inum dir, struct bkey_s_c_dirent d, subvol_inum *target) { struct bch_subvolume s; int ret = 0; if (d.v->d_type == DT_SUBVOL && le32_to_cpu(d.v->d_parent_subvol) != dir.subvol) return 1; if (likely(d.v->d_type != DT_SUBVOL)) { target->subvol = dir.subvol; target->inum = le64_to_cpu(d.v->d_inum); } else { target->subvol = le32_to_cpu(d.v->d_child_subvol); ret = bch2_subvolume_get(trans, target->subvol, true, BTREE_ITER_cached, &s); target->inum = le64_to_cpu(s.inode); } return ret; } int bch2_dirent_rename(struct btree_trans *trans, subvol_inum src_dir, struct bch_hash_info *src_hash, subvol_inum dst_dir, struct bch_hash_info *dst_hash, const struct qstr *src_name, subvol_inum *src_inum, u64 *src_offset, const struct qstr *dst_name, subvol_inum *dst_inum, u64 *dst_offset, enum bch_rename_mode mode) { struct btree_iter src_iter = { NULL }; struct btree_iter dst_iter = { NULL }; struct bkey_s_c old_src, old_dst = bkey_s_c_null; struct bkey_i_dirent *new_src = NULL, *new_dst = NULL; struct bpos dst_pos = POS(dst_dir.inum, bch2_dirent_hash(dst_hash, dst_name)); unsigned src_update_flags = 0; bool delete_src, delete_dst; int ret = 0; memset(src_inum, 0, sizeof(*src_inum)); memset(dst_inum, 0, sizeof(*dst_inum)); /* Lookup src: */ old_src = bch2_hash_lookup(trans, &src_iter, bch2_dirent_hash_desc, src_hash, src_dir, src_name, BTREE_ITER_intent); ret = bkey_err(old_src); if (ret) goto out; ret = bch2_dirent_read_target(trans, src_dir, bkey_s_c_to_dirent(old_src), src_inum); if (ret) goto out; /* Lookup dst: */ if (mode == BCH_RENAME) { /* * Note that we're _not_ checking if the target already exists - * we're relying on the VFS to do that check for us for * correctness: */ ret = bch2_hash_hole(trans, &dst_iter, bch2_dirent_hash_desc, dst_hash, dst_dir, dst_name); if (ret) goto out; } else { old_dst = bch2_hash_lookup(trans, &dst_iter, bch2_dirent_hash_desc, dst_hash, dst_dir, dst_name, BTREE_ITER_intent); ret = bkey_err(old_dst); if (ret) goto out; ret = bch2_dirent_read_target(trans, dst_dir, bkey_s_c_to_dirent(old_dst), dst_inum); if (ret) goto out; } if (mode != BCH_RENAME_EXCHANGE) *src_offset = dst_iter.pos.offset; /* Create new dst key: */ new_dst = dirent_create_key(trans, dst_dir, 0, dst_name, 0); ret = PTR_ERR_OR_ZERO(new_dst); if (ret) goto out; dirent_copy_target(new_dst, bkey_s_c_to_dirent(old_src)); new_dst->k.p = dst_iter.pos; /* Create new src key: */ if (mode == BCH_RENAME_EXCHANGE) { new_src = dirent_create_key(trans, src_dir, 0, src_name, 0); ret = PTR_ERR_OR_ZERO(new_src); if (ret) goto out; dirent_copy_target(new_src, bkey_s_c_to_dirent(old_dst)); new_src->k.p = src_iter.pos; } else { new_src = bch2_trans_kmalloc(trans, sizeof(struct bkey_i)); ret = PTR_ERR_OR_ZERO(new_src); if (ret) goto out; bkey_init(&new_src->k); new_src->k.p = src_iter.pos; if (bkey_le(dst_pos, src_iter.pos) && bkey_lt(src_iter.pos, dst_iter.pos)) { /* * We have a hash collision for the new dst key, * and new_src - the key we're deleting - is between * new_dst's hashed slot and the slot we're going to be * inserting it into - oops. This will break the hash * table if we don't deal with it: */ if (mode == BCH_RENAME) { /* * If we're not overwriting, we can just insert * new_dst at the src position: */ new_src = new_dst; new_src->k.p = src_iter.pos; goto out_set_src; } else { /* If we're overwriting, we can't insert new_dst * at a different slot because it has to * overwrite old_dst - just make sure to use a * whiteout when deleting src: */ new_src->k.type = KEY_TYPE_hash_whiteout; } } else { /* Check if we need a whiteout to delete src: */ ret = bch2_hash_needs_whiteout(trans, bch2_dirent_hash_desc, src_hash, &src_iter); if (ret < 0) goto out; if (ret) new_src->k.type = KEY_TYPE_hash_whiteout; } } if (new_dst->v.d_type == DT_SUBVOL) new_dst->v.d_parent_subvol = cpu_to_le32(dst_dir.subvol); if ((mode == BCH_RENAME_EXCHANGE) && new_src->v.d_type == DT_SUBVOL) new_src->v.d_parent_subvol = cpu_to_le32(src_dir.subvol); ret = bch2_trans_update(trans, &dst_iter, &new_dst->k_i, 0); if (ret) goto out; out_set_src: /* * If we're deleting a subvolume we need to really delete the dirent, * not just emit a whiteout in the current snapshot - there can only be * single dirent that points to a given subvolume. * * IOW, we don't maintain multiple versions in different snapshots of * dirents that point to subvolumes - dirents that point to subvolumes * are only visible in one particular subvolume so it's not necessary, * and it would be particularly confusing for fsck to have to deal with. */ delete_src = bkey_s_c_to_dirent(old_src).v->d_type == DT_SUBVOL && new_src->k.p.snapshot != old_src.k->p.snapshot; delete_dst = old_dst.k && bkey_s_c_to_dirent(old_dst).v->d_type == DT_SUBVOL && new_dst->k.p.snapshot != old_dst.k->p.snapshot; if (!delete_src || !bkey_deleted(&new_src->k)) { ret = bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags); if (ret) goto out; } if (delete_src) { bch2_btree_iter_set_snapshot(&src_iter, old_src.k->p.snapshot); ret = bch2_btree_iter_traverse(&src_iter) ?: bch2_btree_delete_at(trans, &src_iter, BTREE_UPDATE_internal_snapshot_node); if (ret) goto out; } if (delete_dst) { bch2_btree_iter_set_snapshot(&dst_iter, old_dst.k->p.snapshot); ret = bch2_btree_iter_traverse(&dst_iter) ?: bch2_btree_delete_at(trans, &dst_iter, BTREE_UPDATE_internal_snapshot_node); if (ret) goto out; } if (mode == BCH_RENAME_EXCHANGE) *src_offset = new_src->k.p.offset; *dst_offset = new_dst->k.p.offset; out: bch2_trans_iter_exit(trans, &src_iter); bch2_trans_iter_exit(trans, &dst_iter); return ret; } int bch2_dirent_lookup_trans(struct btree_trans *trans, struct btree_iter *iter, subvol_inum dir, const struct bch_hash_info *hash_info, const struct qstr *name, subvol_inum *inum, unsigned flags) { struct bkey_s_c k = bch2_hash_lookup(trans, iter, bch2_dirent_hash_desc, hash_info, dir, name, flags); int ret = bkey_err(k); if (ret) goto err; ret = bch2_dirent_read_target(trans, dir, bkey_s_c_to_dirent(k), inum); if (ret > 0) ret = -ENOENT; err: if (ret) bch2_trans_iter_exit(trans, iter); return ret; } u64 bch2_dirent_lookup(struct bch_fs *c, subvol_inum dir, const struct bch_hash_info *hash_info, const struct qstr *name, subvol_inum *inum) { struct btree_trans *trans = bch2_trans_get(c); struct btree_iter iter = { NULL }; int ret = lockrestart_do(trans, bch2_dirent_lookup_trans(trans, &iter, dir, hash_info, name, inum, 0)); bch2_trans_iter_exit(trans, &iter); bch2_trans_put(trans); return ret; } int bch2_empty_dir_snapshot(struct btree_trans *trans, u64 dir, u32 subvol, u32 snapshot) { struct btree_iter iter; struct bkey_s_c k; int ret; for_each_btree_key_upto_norestart(trans, iter, BTREE_ID_dirents, SPOS(dir, 0, snapshot), POS(dir, U64_MAX), 0, k, ret) if (k.k->type == KEY_TYPE_dirent) { struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k); if (d.v->d_type == DT_SUBVOL && le32_to_cpu(d.v->d_parent_subvol) != subvol) continue; ret = -BCH_ERR_ENOTEMPTY_dir_not_empty; break; } bch2_trans_iter_exit(trans, &iter); return ret; } int bch2_empty_dir_trans(struct btree_trans *trans, subvol_inum dir) { u32 snapshot; return bch2_subvolume_get_snapshot(trans, dir.subvol, &snapshot) ?: bch2_empty_dir_snapshot(trans, dir.inum, dir.subvol, snapshot); } int bch2_readdir(struct bch_fs *c, subvol_inum inum, struct dir_context *ctx) { struct btree_trans *trans = bch2_trans_get(c); struct btree_iter iter; struct bkey_s_c k; struct bkey_s_c_dirent dirent; subvol_inum target; u32 snapshot; struct bkey_buf sk; struct qstr name; int ret; bch2_bkey_buf_init(&sk); retry: bch2_trans_begin(trans); ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot); if (ret) goto err; for_each_btree_key_upto_norestart(trans, iter, BTREE_ID_dirents, SPOS(inum.inum, ctx->pos, snapshot), POS(inum.inum, U64_MAX), 0, k, ret) { if (k.k->type != KEY_TYPE_dirent) continue; dirent = bkey_s_c_to_dirent(k); ret = bch2_dirent_read_target(trans, inum, dirent, &target); if (ret < 0) break; if (ret) continue; /* dir_emit() can fault and block: */ bch2_bkey_buf_reassemble(&sk, c, k); dirent = bkey_i_to_s_c_dirent(sk.k); bch2_trans_unlock(trans); name = bch2_dirent_get_name(dirent); ctx->pos = dirent.k->p.offset; if (!dir_emit(ctx, name.name, name.len, target.inum, vfs_d_type(dirent.v->d_type))) break; ctx->pos = dirent.k->p.offset + 1; /* * read_target looks up subvolumes, we can overflow paths if the * directory has many subvolumes in it */ ret = btree_trans_too_many_iters(trans); if (ret) break; } bch2_trans_iter_exit(trans, &iter); err: if (bch2_err_matches(ret, BCH_ERR_transaction_restart)) goto retry; bch2_trans_put(trans); bch2_bkey_buf_exit(&sk, c); return ret; }