| // SPDX-License-Identifier: GPL-2.0 |
| |
| #include "bcachefs.h" |
| #include "bkey_buf.h" |
| #include "btree_key_cache.h" |
| #include "btree_update.h" |
| #include "buckets.h" |
| #include "errcode.h" |
| #include "error.h" |
| #include "fs.h" |
| #include "recovery_passes.h" |
| #include "snapshot.h" |
| |
| #include <linux/random.h> |
| |
| /* |
| * Snapshot trees: |
| * |
| * Keys in BTREE_ID_snapshot_trees identify a whole tree of snapshot nodes; they |
| * exist to provide a stable identifier for the whole lifetime of a snapshot |
| * tree. |
| */ |
| |
| void bch2_snapshot_tree_to_text(struct printbuf *out, struct bch_fs *c, |
| struct bkey_s_c k) |
| { |
| struct bkey_s_c_snapshot_tree t = bkey_s_c_to_snapshot_tree(k); |
| |
| prt_printf(out, "subvol %u root snapshot %u", |
| le32_to_cpu(t.v->master_subvol), |
| le32_to_cpu(t.v->root_snapshot)); |
| } |
| |
| int bch2_snapshot_tree_validate(struct bch_fs *c, struct bkey_s_c k, |
| enum bch_validate_flags flags) |
| { |
| int ret = 0; |
| |
| bkey_fsck_err_on(bkey_gt(k.k->p, POS(0, U32_MAX)) || |
| bkey_lt(k.k->p, POS(0, 1)), |
| c, snapshot_tree_pos_bad, |
| "bad pos"); |
| fsck_err: |
| return ret; |
| } |
| |
| int bch2_snapshot_tree_lookup(struct btree_trans *trans, u32 id, |
| struct bch_snapshot_tree *s) |
| { |
| int ret = bch2_bkey_get_val_typed(trans, BTREE_ID_snapshot_trees, POS(0, id), |
| BTREE_ITER_with_updates, snapshot_tree, s); |
| |
| if (bch2_err_matches(ret, ENOENT)) |
| ret = -BCH_ERR_ENOENT_snapshot_tree; |
| return ret; |
| } |
| |
| struct bkey_i_snapshot_tree * |
| __bch2_snapshot_tree_create(struct btree_trans *trans) |
| { |
| struct btree_iter iter; |
| int ret = bch2_bkey_get_empty_slot(trans, &iter, |
| BTREE_ID_snapshot_trees, POS(0, U32_MAX)); |
| struct bkey_i_snapshot_tree *s_t; |
| |
| if (ret == -BCH_ERR_ENOSPC_btree_slot) |
| ret = -BCH_ERR_ENOSPC_snapshot_tree; |
| if (ret) |
| return ERR_PTR(ret); |
| |
| s_t = bch2_bkey_alloc(trans, &iter, 0, snapshot_tree); |
| ret = PTR_ERR_OR_ZERO(s_t); |
| bch2_trans_iter_exit(trans, &iter); |
| return ret ? ERR_PTR(ret) : s_t; |
| } |
| |
| static int bch2_snapshot_tree_create(struct btree_trans *trans, |
| u32 root_id, u32 subvol_id, u32 *tree_id) |
| { |
| struct bkey_i_snapshot_tree *n_tree = |
| __bch2_snapshot_tree_create(trans); |
| |
| if (IS_ERR(n_tree)) |
| return PTR_ERR(n_tree); |
| |
| n_tree->v.master_subvol = cpu_to_le32(subvol_id); |
| n_tree->v.root_snapshot = cpu_to_le32(root_id); |
| *tree_id = n_tree->k.p.offset; |
| return 0; |
| } |
| |
| /* Snapshot nodes: */ |
| |
| static bool __bch2_snapshot_is_ancestor_early(struct snapshot_table *t, u32 id, u32 ancestor) |
| { |
| while (id && id < ancestor) { |
| const struct snapshot_t *s = __snapshot_t(t, id); |
| id = s ? s->parent : 0; |
| } |
| return id == ancestor; |
| } |
| |
| static bool bch2_snapshot_is_ancestor_early(struct bch_fs *c, u32 id, u32 ancestor) |
| { |
| rcu_read_lock(); |
| bool ret = __bch2_snapshot_is_ancestor_early(rcu_dereference(c->snapshots), id, ancestor); |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| |
| static inline u32 get_ancestor_below(struct snapshot_table *t, u32 id, u32 ancestor) |
| { |
| const struct snapshot_t *s = __snapshot_t(t, id); |
| if (!s) |
| return 0; |
| |
| if (s->skip[2] <= ancestor) |
| return s->skip[2]; |
| if (s->skip[1] <= ancestor) |
| return s->skip[1]; |
| if (s->skip[0] <= ancestor) |
| return s->skip[0]; |
| return s->parent; |
| } |
| |
| static bool test_ancestor_bitmap(struct snapshot_table *t, u32 id, u32 ancestor) |
| { |
| const struct snapshot_t *s = __snapshot_t(t, id); |
| if (!s) |
| return false; |
| |
| return test_bit(ancestor - id - 1, s->is_ancestor); |
| } |
| |
| bool __bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor) |
| { |
| bool ret; |
| |
| rcu_read_lock(); |
| struct snapshot_table *t = rcu_dereference(c->snapshots); |
| |
| if (unlikely(c->recovery_pass_done < BCH_RECOVERY_PASS_check_snapshots)) { |
| ret = __bch2_snapshot_is_ancestor_early(t, id, ancestor); |
| goto out; |
| } |
| |
| while (id && id < ancestor - IS_ANCESTOR_BITMAP) |
| id = get_ancestor_below(t, id, ancestor); |
| |
| ret = id && id < ancestor |
| ? test_ancestor_bitmap(t, id, ancestor) |
| : id == ancestor; |
| |
| EBUG_ON(ret != __bch2_snapshot_is_ancestor_early(t, id, ancestor)); |
| out: |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| |
| static noinline struct snapshot_t *__snapshot_t_mut(struct bch_fs *c, u32 id) |
| { |
| size_t idx = U32_MAX - id; |
| struct snapshot_table *new, *old; |
| |
| size_t new_bytes = kmalloc_size_roundup(struct_size(new, s, idx + 1)); |
| size_t new_size = (new_bytes - sizeof(*new)) / sizeof(new->s[0]); |
| |
| if (unlikely(new_bytes > INT_MAX)) |
| return NULL; |
| |
| new = kvzalloc(new_bytes, GFP_KERNEL); |
| if (!new) |
| return NULL; |
| |
| new->nr = new_size; |
| |
| old = rcu_dereference_protected(c->snapshots, true); |
| if (old) |
| memcpy(new->s, old->s, sizeof(old->s[0]) * old->nr); |
| |
| rcu_assign_pointer(c->snapshots, new); |
| kvfree_rcu(old, rcu); |
| |
| return &rcu_dereference_protected(c->snapshots, |
| lockdep_is_held(&c->snapshot_table_lock))->s[idx]; |
| } |
| |
| static inline struct snapshot_t *snapshot_t_mut(struct bch_fs *c, u32 id) |
| { |
| size_t idx = U32_MAX - id; |
| struct snapshot_table *table = |
| rcu_dereference_protected(c->snapshots, |
| lockdep_is_held(&c->snapshot_table_lock)); |
| |
| lockdep_assert_held(&c->snapshot_table_lock); |
| |
| if (likely(table && idx < table->nr)) |
| return &table->s[idx]; |
| |
| return __snapshot_t_mut(c, id); |
| } |
| |
| void bch2_snapshot_to_text(struct printbuf *out, struct bch_fs *c, |
| struct bkey_s_c k) |
| { |
| struct bkey_s_c_snapshot s = bkey_s_c_to_snapshot(k); |
| |
| prt_printf(out, "is_subvol %llu deleted %llu parent %10u children %10u %10u subvol %u tree %u", |
| BCH_SNAPSHOT_SUBVOL(s.v), |
| BCH_SNAPSHOT_DELETED(s.v), |
| le32_to_cpu(s.v->parent), |
| le32_to_cpu(s.v->children[0]), |
| le32_to_cpu(s.v->children[1]), |
| le32_to_cpu(s.v->subvol), |
| le32_to_cpu(s.v->tree)); |
| |
| if (bkey_val_bytes(k.k) > offsetof(struct bch_snapshot, depth)) |
| prt_printf(out, " depth %u skiplist %u %u %u", |
| le32_to_cpu(s.v->depth), |
| le32_to_cpu(s.v->skip[0]), |
| le32_to_cpu(s.v->skip[1]), |
| le32_to_cpu(s.v->skip[2])); |
| } |
| |
| int bch2_snapshot_validate(struct bch_fs *c, struct bkey_s_c k, |
| enum bch_validate_flags flags) |
| { |
| struct bkey_s_c_snapshot s; |
| u32 i, id; |
| int ret = 0; |
| |
| bkey_fsck_err_on(bkey_gt(k.k->p, POS(0, U32_MAX)) || |
| bkey_lt(k.k->p, POS(0, 1)), |
| c, snapshot_pos_bad, |
| "bad pos"); |
| |
| s = bkey_s_c_to_snapshot(k); |
| |
| id = le32_to_cpu(s.v->parent); |
| bkey_fsck_err_on(id && id <= k.k->p.offset, |
| c, snapshot_parent_bad, |
| "bad parent node (%u <= %llu)", |
| id, k.k->p.offset); |
| |
| bkey_fsck_err_on(le32_to_cpu(s.v->children[0]) < le32_to_cpu(s.v->children[1]), |
| c, snapshot_children_not_normalized, |
| "children not normalized"); |
| |
| bkey_fsck_err_on(s.v->children[0] && s.v->children[0] == s.v->children[1], |
| c, snapshot_child_duplicate, |
| "duplicate child nodes"); |
| |
| for (i = 0; i < 2; i++) { |
| id = le32_to_cpu(s.v->children[i]); |
| |
| bkey_fsck_err_on(id >= k.k->p.offset, |
| c, snapshot_child_bad, |
| "bad child node (%u >= %llu)", |
| id, k.k->p.offset); |
| } |
| |
| if (bkey_val_bytes(k.k) > offsetof(struct bch_snapshot, skip)) { |
| bkey_fsck_err_on(le32_to_cpu(s.v->skip[0]) > le32_to_cpu(s.v->skip[1]) || |
| le32_to_cpu(s.v->skip[1]) > le32_to_cpu(s.v->skip[2]), |
| c, snapshot_skiplist_not_normalized, |
| "skiplist not normalized"); |
| |
| for (i = 0; i < ARRAY_SIZE(s.v->skip); i++) { |
| id = le32_to_cpu(s.v->skip[i]); |
| |
| bkey_fsck_err_on(id && id < le32_to_cpu(s.v->parent), |
| c, snapshot_skiplist_bad, |
| "bad skiplist node %u", id); |
| } |
| } |
| fsck_err: |
| return ret; |
| } |
| |
| static void __set_is_ancestor_bitmap(struct bch_fs *c, u32 id) |
| { |
| struct snapshot_t *t = snapshot_t_mut(c, id); |
| u32 parent = id; |
| |
| while ((parent = bch2_snapshot_parent_early(c, parent)) && |
| parent - id - 1 < IS_ANCESTOR_BITMAP) |
| __set_bit(parent - id - 1, t->is_ancestor); |
| } |
| |
| static void set_is_ancestor_bitmap(struct bch_fs *c, u32 id) |
| { |
| mutex_lock(&c->snapshot_table_lock); |
| __set_is_ancestor_bitmap(c, id); |
| mutex_unlock(&c->snapshot_table_lock); |
| } |
| |
| static int __bch2_mark_snapshot(struct btree_trans *trans, |
| enum btree_id btree, unsigned level, |
| struct bkey_s_c old, struct bkey_s_c new, |
| enum btree_iter_update_trigger_flags flags) |
| { |
| struct bch_fs *c = trans->c; |
| struct snapshot_t *t; |
| u32 id = new.k->p.offset; |
| int ret = 0; |
| |
| mutex_lock(&c->snapshot_table_lock); |
| |
| t = snapshot_t_mut(c, id); |
| if (!t) { |
| ret = -BCH_ERR_ENOMEM_mark_snapshot; |
| goto err; |
| } |
| |
| if (new.k->type == KEY_TYPE_snapshot) { |
| struct bkey_s_c_snapshot s = bkey_s_c_to_snapshot(new); |
| |
| t->parent = le32_to_cpu(s.v->parent); |
| t->children[0] = le32_to_cpu(s.v->children[0]); |
| t->children[1] = le32_to_cpu(s.v->children[1]); |
| t->subvol = BCH_SNAPSHOT_SUBVOL(s.v) ? le32_to_cpu(s.v->subvol) : 0; |
| t->tree = le32_to_cpu(s.v->tree); |
| |
| if (bkey_val_bytes(s.k) > offsetof(struct bch_snapshot, depth)) { |
| t->depth = le32_to_cpu(s.v->depth); |
| t->skip[0] = le32_to_cpu(s.v->skip[0]); |
| t->skip[1] = le32_to_cpu(s.v->skip[1]); |
| t->skip[2] = le32_to_cpu(s.v->skip[2]); |
| } else { |
| t->depth = 0; |
| t->skip[0] = 0; |
| t->skip[1] = 0; |
| t->skip[2] = 0; |
| } |
| |
| __set_is_ancestor_bitmap(c, id); |
| |
| if (BCH_SNAPSHOT_DELETED(s.v)) { |
| set_bit(BCH_FS_need_delete_dead_snapshots, &c->flags); |
| if (c->curr_recovery_pass > BCH_RECOVERY_PASS_delete_dead_snapshots) |
| bch2_delete_dead_snapshots_async(c); |
| } |
| } else { |
| memset(t, 0, sizeof(*t)); |
| } |
| err: |
| mutex_unlock(&c->snapshot_table_lock); |
| return ret; |
| } |
| |
| int bch2_mark_snapshot(struct btree_trans *trans, |
| enum btree_id btree, unsigned level, |
| struct bkey_s_c old, struct bkey_s new, |
| enum btree_iter_update_trigger_flags flags) |
| { |
| return __bch2_mark_snapshot(trans, btree, level, old, new.s_c, flags); |
| } |
| |
| int bch2_snapshot_lookup(struct btree_trans *trans, u32 id, |
| struct bch_snapshot *s) |
| { |
| return bch2_bkey_get_val_typed(trans, BTREE_ID_snapshots, POS(0, id), |
| BTREE_ITER_with_updates, snapshot, s); |
| } |
| |
| static int bch2_snapshot_live(struct btree_trans *trans, u32 id) |
| { |
| struct bch_snapshot v; |
| int ret; |
| |
| if (!id) |
| return 0; |
| |
| ret = bch2_snapshot_lookup(trans, id, &v); |
| if (bch2_err_matches(ret, ENOENT)) |
| bch_err(trans->c, "snapshot node %u not found", id); |
| if (ret) |
| return ret; |
| |
| return !BCH_SNAPSHOT_DELETED(&v); |
| } |
| |
| /* |
| * If @k is a snapshot with just one live child, it's part of a linear chain, |
| * which we consider to be an equivalence class: and then after snapshot |
| * deletion cleanup, there should only be a single key at a given position in |
| * this equivalence class. |
| * |
| * This sets the equivalence class of @k to be the child's equivalence class, if |
| * it's part of such a linear chain: this correctly sets equivalence classes on |
| * startup if we run leaf to root (i.e. in natural key order). |
| */ |
| static int bch2_snapshot_set_equiv(struct btree_trans *trans, struct bkey_s_c k) |
| { |
| struct bch_fs *c = trans->c; |
| unsigned i, nr_live = 0, live_idx = 0; |
| struct bkey_s_c_snapshot snap; |
| u32 id = k.k->p.offset, child[2]; |
| |
| if (k.k->type != KEY_TYPE_snapshot) |
| return 0; |
| |
| snap = bkey_s_c_to_snapshot(k); |
| |
| child[0] = le32_to_cpu(snap.v->children[0]); |
| child[1] = le32_to_cpu(snap.v->children[1]); |
| |
| for (i = 0; i < 2; i++) { |
| int ret = bch2_snapshot_live(trans, child[i]); |
| |
| if (ret < 0) |
| return ret; |
| |
| if (ret) |
| live_idx = i; |
| nr_live += ret; |
| } |
| |
| mutex_lock(&c->snapshot_table_lock); |
| |
| snapshot_t_mut(c, id)->equiv = nr_live == 1 |
| ? snapshot_t_mut(c, child[live_idx])->equiv |
| : id; |
| |
| mutex_unlock(&c->snapshot_table_lock); |
| |
| return 0; |
| } |
| |
| /* fsck: */ |
| |
| static u32 bch2_snapshot_child(struct bch_fs *c, u32 id, unsigned child) |
| { |
| return snapshot_t(c, id)->children[child]; |
| } |
| |
| static u32 bch2_snapshot_left_child(struct bch_fs *c, u32 id) |
| { |
| return bch2_snapshot_child(c, id, 0); |
| } |
| |
| static u32 bch2_snapshot_right_child(struct bch_fs *c, u32 id) |
| { |
| return bch2_snapshot_child(c, id, 1); |
| } |
| |
| static u32 bch2_snapshot_tree_next(struct bch_fs *c, u32 id) |
| { |
| u32 n, parent; |
| |
| n = bch2_snapshot_left_child(c, id); |
| if (n) |
| return n; |
| |
| while ((parent = bch2_snapshot_parent(c, id))) { |
| n = bch2_snapshot_right_child(c, parent); |
| if (n && n != id) |
| return n; |
| id = parent; |
| } |
| |
| return 0; |
| } |
| |
| static u32 bch2_snapshot_tree_oldest_subvol(struct bch_fs *c, u32 snapshot_root) |
| { |
| u32 id = snapshot_root; |
| u32 subvol = 0, s; |
| |
| rcu_read_lock(); |
| while (id) { |
| s = snapshot_t(c, id)->subvol; |
| |
| if (s && (!subvol || s < subvol)) |
| subvol = s; |
| |
| id = bch2_snapshot_tree_next(c, id); |
| } |
| rcu_read_unlock(); |
| |
| return subvol; |
| } |
| |
| static int bch2_snapshot_tree_master_subvol(struct btree_trans *trans, |
| u32 snapshot_root, u32 *subvol_id) |
| { |
| struct bch_fs *c = trans->c; |
| struct btree_iter iter; |
| struct bkey_s_c k; |
| bool found = false; |
| int ret; |
| |
| for_each_btree_key_norestart(trans, iter, BTREE_ID_subvolumes, POS_MIN, |
| 0, k, ret) { |
| if (k.k->type != KEY_TYPE_subvolume) |
| continue; |
| |
| struct bkey_s_c_subvolume s = bkey_s_c_to_subvolume(k); |
| if (!bch2_snapshot_is_ancestor(c, le32_to_cpu(s.v->snapshot), snapshot_root)) |
| continue; |
| if (!BCH_SUBVOLUME_SNAP(s.v)) { |
| *subvol_id = s.k->p.offset; |
| found = true; |
| break; |
| } |
| } |
| |
| bch2_trans_iter_exit(trans, &iter); |
| |
| if (!ret && !found) { |
| struct bkey_i_subvolume *u; |
| |
| *subvol_id = bch2_snapshot_tree_oldest_subvol(c, snapshot_root); |
| |
| u = bch2_bkey_get_mut_typed(trans, &iter, |
| BTREE_ID_subvolumes, POS(0, *subvol_id), |
| 0, subvolume); |
| ret = PTR_ERR_OR_ZERO(u); |
| if (ret) |
| return ret; |
| |
| SET_BCH_SUBVOLUME_SNAP(&u->v, false); |
| } |
| |
| return ret; |
| } |
| |
| static int check_snapshot_tree(struct btree_trans *trans, |
| struct btree_iter *iter, |
| struct bkey_s_c k) |
| { |
| struct bch_fs *c = trans->c; |
| struct bkey_s_c_snapshot_tree st; |
| struct bch_snapshot s; |
| struct bch_subvolume subvol; |
| struct printbuf buf = PRINTBUF; |
| u32 root_id; |
| int ret; |
| |
| if (k.k->type != KEY_TYPE_snapshot_tree) |
| return 0; |
| |
| st = bkey_s_c_to_snapshot_tree(k); |
| root_id = le32_to_cpu(st.v->root_snapshot); |
| |
| ret = bch2_snapshot_lookup(trans, root_id, &s); |
| if (ret && !bch2_err_matches(ret, ENOENT)) |
| goto err; |
| |
| if (fsck_err_on(ret || |
| root_id != bch2_snapshot_root(c, root_id) || |
| st.k->p.offset != le32_to_cpu(s.tree), |
| trans, snapshot_tree_to_missing_snapshot, |
| "snapshot tree points to missing/incorrect snapshot:\n %s", |
| (bch2_bkey_val_to_text(&buf, c, st.s_c), buf.buf))) { |
| ret = bch2_btree_delete_at(trans, iter, 0); |
| goto err; |
| } |
| |
| ret = bch2_subvolume_get(trans, le32_to_cpu(st.v->master_subvol), |
| false, 0, &subvol); |
| if (ret && !bch2_err_matches(ret, ENOENT)) |
| goto err; |
| |
| if (fsck_err_on(ret, |
| trans, snapshot_tree_to_missing_subvol, |
| "snapshot tree points to missing subvolume:\n %s", |
| (printbuf_reset(&buf), |
| bch2_bkey_val_to_text(&buf, c, st.s_c), buf.buf)) || |
| fsck_err_on(!bch2_snapshot_is_ancestor(c, |
| le32_to_cpu(subvol.snapshot), |
| root_id), |
| trans, snapshot_tree_to_wrong_subvol, |
| "snapshot tree points to subvolume that does not point to snapshot in this tree:\n %s", |
| (printbuf_reset(&buf), |
| bch2_bkey_val_to_text(&buf, c, st.s_c), buf.buf)) || |
| fsck_err_on(BCH_SUBVOLUME_SNAP(&subvol), |
| trans, snapshot_tree_to_snapshot_subvol, |
| "snapshot tree points to snapshot subvolume:\n %s", |
| (printbuf_reset(&buf), |
| bch2_bkey_val_to_text(&buf, c, st.s_c), buf.buf))) { |
| struct bkey_i_snapshot_tree *u; |
| u32 subvol_id; |
| |
| ret = bch2_snapshot_tree_master_subvol(trans, root_id, &subvol_id); |
| bch_err_fn(c, ret); |
| |
| if (bch2_err_matches(ret, ENOENT)) { /* nothing to be done here */ |
| ret = 0; |
| goto err; |
| } |
| |
| if (ret) |
| goto err; |
| |
| u = bch2_bkey_make_mut_typed(trans, iter, &k, 0, snapshot_tree); |
| ret = PTR_ERR_OR_ZERO(u); |
| if (ret) |
| goto err; |
| |
| u->v.master_subvol = cpu_to_le32(subvol_id); |
| st = snapshot_tree_i_to_s_c(u); |
| } |
| err: |
| fsck_err: |
| printbuf_exit(&buf); |
| return ret; |
| } |
| |
| /* |
| * For each snapshot_tree, make sure it points to the root of a snapshot tree |
| * and that snapshot entry points back to it, or delete it. |
| * |
| * And, make sure it points to a subvolume within that snapshot tree, or correct |
| * it to point to the oldest subvolume within that snapshot tree. |
| */ |
| int bch2_check_snapshot_trees(struct bch_fs *c) |
| { |
| int ret = bch2_trans_run(c, |
| for_each_btree_key_commit(trans, iter, |
| BTREE_ID_snapshot_trees, POS_MIN, |
| BTREE_ITER_prefetch, k, |
| NULL, NULL, BCH_TRANS_COMMIT_no_enospc, |
| check_snapshot_tree(trans, &iter, k))); |
| bch_err_fn(c, ret); |
| return ret; |
| } |
| |
| /* |
| * Look up snapshot tree for @tree_id and find root, |
| * make sure @snap_id is a descendent: |
| */ |
| static int snapshot_tree_ptr_good(struct btree_trans *trans, |
| u32 snap_id, u32 tree_id) |
| { |
| struct bch_snapshot_tree s_t; |
| int ret = bch2_snapshot_tree_lookup(trans, tree_id, &s_t); |
| |
| if (bch2_err_matches(ret, ENOENT)) |
| return 0; |
| if (ret) |
| return ret; |
| |
| return bch2_snapshot_is_ancestor_early(trans->c, snap_id, le32_to_cpu(s_t.root_snapshot)); |
| } |
| |
| u32 bch2_snapshot_skiplist_get(struct bch_fs *c, u32 id) |
| { |
| const struct snapshot_t *s; |
| |
| if (!id) |
| return 0; |
| |
| rcu_read_lock(); |
| s = snapshot_t(c, id); |
| if (s->parent) |
| id = bch2_snapshot_nth_parent(c, id, get_random_u32_below(s->depth)); |
| rcu_read_unlock(); |
| |
| return id; |
| } |
| |
| static int snapshot_skiplist_good(struct btree_trans *trans, u32 id, struct bch_snapshot s) |
| { |
| unsigned i; |
| |
| for (i = 0; i < 3; i++) |
| if (!s.parent) { |
| if (s.skip[i]) |
| return false; |
| } else { |
| if (!bch2_snapshot_is_ancestor_early(trans->c, id, le32_to_cpu(s.skip[i]))) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /* |
| * snapshot_tree pointer was incorrect: look up root snapshot node, make sure |
| * its snapshot_tree pointer is correct (allocate new one if necessary), then |
| * update this node's pointer to root node's pointer: |
| */ |
| static int snapshot_tree_ptr_repair(struct btree_trans *trans, |
| struct btree_iter *iter, |
| struct bkey_s_c k, |
| struct bch_snapshot *s) |
| { |
| struct bch_fs *c = trans->c; |
| struct btree_iter root_iter; |
| struct bch_snapshot_tree s_t; |
| struct bkey_s_c_snapshot root; |
| struct bkey_i_snapshot *u; |
| u32 root_id = bch2_snapshot_root(c, k.k->p.offset), tree_id; |
| int ret; |
| |
| root = bch2_bkey_get_iter_typed(trans, &root_iter, |
| BTREE_ID_snapshots, POS(0, root_id), |
| BTREE_ITER_with_updates, snapshot); |
| ret = bkey_err(root); |
| if (ret) |
| goto err; |
| |
| tree_id = le32_to_cpu(root.v->tree); |
| |
| ret = bch2_snapshot_tree_lookup(trans, tree_id, &s_t); |
| if (ret && !bch2_err_matches(ret, ENOENT)) |
| return ret; |
| |
| if (ret || le32_to_cpu(s_t.root_snapshot) != root_id) { |
| u = bch2_bkey_make_mut_typed(trans, &root_iter, &root.s_c, 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(u) ?: |
| bch2_snapshot_tree_create(trans, root_id, |
| bch2_snapshot_tree_oldest_subvol(c, root_id), |
| &tree_id); |
| if (ret) |
| goto err; |
| |
| u->v.tree = cpu_to_le32(tree_id); |
| if (k.k->p.offset == root_id) |
| *s = u->v; |
| } |
| |
| if (k.k->p.offset != root_id) { |
| u = bch2_bkey_make_mut_typed(trans, iter, &k, 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(u); |
| if (ret) |
| goto err; |
| |
| u->v.tree = cpu_to_le32(tree_id); |
| *s = u->v; |
| } |
| err: |
| bch2_trans_iter_exit(trans, &root_iter); |
| return ret; |
| } |
| |
| static int check_snapshot(struct btree_trans *trans, |
| struct btree_iter *iter, |
| struct bkey_s_c k) |
| { |
| struct bch_fs *c = trans->c; |
| struct bch_snapshot s; |
| struct bch_subvolume subvol; |
| struct bch_snapshot v; |
| struct bkey_i_snapshot *u; |
| u32 parent_id = bch2_snapshot_parent_early(c, k.k->p.offset); |
| u32 real_depth; |
| struct printbuf buf = PRINTBUF; |
| u32 i, id; |
| int ret = 0; |
| |
| if (k.k->type != KEY_TYPE_snapshot) |
| return 0; |
| |
| memset(&s, 0, sizeof(s)); |
| memcpy(&s, k.v, min(sizeof(s), bkey_val_bytes(k.k))); |
| |
| id = le32_to_cpu(s.parent); |
| if (id) { |
| ret = bch2_snapshot_lookup(trans, id, &v); |
| if (bch2_err_matches(ret, ENOENT)) |
| bch_err(c, "snapshot with nonexistent parent:\n %s", |
| (bch2_bkey_val_to_text(&buf, c, k), buf.buf)); |
| if (ret) |
| goto err; |
| |
| if (le32_to_cpu(v.children[0]) != k.k->p.offset && |
| le32_to_cpu(v.children[1]) != k.k->p.offset) { |
| bch_err(c, "snapshot parent %u missing pointer to child %llu", |
| id, k.k->p.offset); |
| ret = -EINVAL; |
| goto err; |
| } |
| } |
| |
| for (i = 0; i < 2 && s.children[i]; i++) { |
| id = le32_to_cpu(s.children[i]); |
| |
| ret = bch2_snapshot_lookup(trans, id, &v); |
| if (bch2_err_matches(ret, ENOENT)) |
| bch_err(c, "snapshot node %llu has nonexistent child %u", |
| k.k->p.offset, id); |
| if (ret) |
| goto err; |
| |
| if (le32_to_cpu(v.parent) != k.k->p.offset) { |
| bch_err(c, "snapshot child %u has wrong parent (got %u should be %llu)", |
| id, le32_to_cpu(v.parent), k.k->p.offset); |
| ret = -EINVAL; |
| goto err; |
| } |
| } |
| |
| bool should_have_subvol = BCH_SNAPSHOT_SUBVOL(&s) && |
| !BCH_SNAPSHOT_DELETED(&s); |
| |
| if (should_have_subvol) { |
| id = le32_to_cpu(s.subvol); |
| ret = bch2_subvolume_get(trans, id, 0, false, &subvol); |
| if (bch2_err_matches(ret, ENOENT)) |
| bch_err(c, "snapshot points to nonexistent subvolume:\n %s", |
| (bch2_bkey_val_to_text(&buf, c, k), buf.buf)); |
| if (ret) |
| goto err; |
| |
| if (BCH_SNAPSHOT_SUBVOL(&s) != (le32_to_cpu(subvol.snapshot) == k.k->p.offset)) { |
| bch_err(c, "snapshot node %llu has wrong BCH_SNAPSHOT_SUBVOL", |
| k.k->p.offset); |
| ret = -EINVAL; |
| goto err; |
| } |
| } else { |
| if (fsck_err_on(s.subvol, |
| trans, snapshot_should_not_have_subvol, |
| "snapshot should not point to subvol:\n %s", |
| (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) { |
| u = bch2_bkey_make_mut_typed(trans, iter, &k, 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(u); |
| if (ret) |
| goto err; |
| |
| u->v.subvol = 0; |
| s = u->v; |
| } |
| } |
| |
| ret = snapshot_tree_ptr_good(trans, k.k->p.offset, le32_to_cpu(s.tree)); |
| if (ret < 0) |
| goto err; |
| |
| if (fsck_err_on(!ret, |
| trans, snapshot_to_bad_snapshot_tree, |
| "snapshot points to missing/incorrect tree:\n %s", |
| (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) { |
| ret = snapshot_tree_ptr_repair(trans, iter, k, &s); |
| if (ret) |
| goto err; |
| } |
| ret = 0; |
| |
| real_depth = bch2_snapshot_depth(c, parent_id); |
| |
| if (fsck_err_on(le32_to_cpu(s.depth) != real_depth, |
| trans, snapshot_bad_depth, |
| "snapshot with incorrect depth field, should be %u:\n %s", |
| real_depth, (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) { |
| u = bch2_bkey_make_mut_typed(trans, iter, &k, 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(u); |
| if (ret) |
| goto err; |
| |
| u->v.depth = cpu_to_le32(real_depth); |
| s = u->v; |
| } |
| |
| ret = snapshot_skiplist_good(trans, k.k->p.offset, s); |
| if (ret < 0) |
| goto err; |
| |
| if (fsck_err_on(!ret, |
| trans, snapshot_bad_skiplist, |
| "snapshot with bad skiplist field:\n %s", |
| (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) { |
| u = bch2_bkey_make_mut_typed(trans, iter, &k, 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(u); |
| if (ret) |
| goto err; |
| |
| for (i = 0; i < ARRAY_SIZE(u->v.skip); i++) |
| u->v.skip[i] = cpu_to_le32(bch2_snapshot_skiplist_get(c, parent_id)); |
| |
| bubble_sort(u->v.skip, ARRAY_SIZE(u->v.skip), cmp_le32); |
| s = u->v; |
| } |
| ret = 0; |
| err: |
| fsck_err: |
| printbuf_exit(&buf); |
| return ret; |
| } |
| |
| int bch2_check_snapshots(struct bch_fs *c) |
| { |
| /* |
| * We iterate backwards as checking/fixing the depth field requires that |
| * the parent's depth already be correct: |
| */ |
| int ret = bch2_trans_run(c, |
| for_each_btree_key_reverse_commit(trans, iter, |
| BTREE_ID_snapshots, POS_MAX, |
| BTREE_ITER_prefetch, k, |
| NULL, NULL, BCH_TRANS_COMMIT_no_enospc, |
| check_snapshot(trans, &iter, k))); |
| bch_err_fn(c, ret); |
| return ret; |
| } |
| |
| static int check_snapshot_exists(struct btree_trans *trans, u32 id) |
| { |
| struct bch_fs *c = trans->c; |
| |
| if (bch2_snapshot_equiv(c, id)) |
| return 0; |
| |
| /* 0 is an invalid tree ID */ |
| u32 tree_id = 0; |
| int ret = bch2_snapshot_tree_create(trans, id, 0, &tree_id); |
| if (ret) |
| return ret; |
| |
| struct bkey_i_snapshot *snapshot = bch2_trans_kmalloc(trans, sizeof(*snapshot)); |
| ret = PTR_ERR_OR_ZERO(snapshot); |
| if (ret) |
| return ret; |
| |
| bkey_snapshot_init(&snapshot->k_i); |
| snapshot->k.p = POS(0, id); |
| snapshot->v.tree = cpu_to_le32(tree_id); |
| snapshot->v.btime.lo = cpu_to_le64(bch2_current_time(c)); |
| |
| return bch2_btree_insert_trans(trans, BTREE_ID_snapshots, &snapshot->k_i, 0) ?: |
| bch2_mark_snapshot(trans, BTREE_ID_snapshots, 0, |
| bkey_s_c_null, bkey_i_to_s(&snapshot->k_i), 0) ?: |
| bch2_snapshot_set_equiv(trans, bkey_i_to_s_c(&snapshot->k_i)); |
| } |
| |
| /* Figure out which snapshot nodes belong in the same tree: */ |
| struct snapshot_tree_reconstruct { |
| enum btree_id btree; |
| struct bpos cur_pos; |
| snapshot_id_list cur_ids; |
| DARRAY(snapshot_id_list) trees; |
| }; |
| |
| static void snapshot_tree_reconstruct_exit(struct snapshot_tree_reconstruct *r) |
| { |
| darray_for_each(r->trees, i) |
| darray_exit(i); |
| darray_exit(&r->trees); |
| darray_exit(&r->cur_ids); |
| } |
| |
| static inline bool same_snapshot(struct snapshot_tree_reconstruct *r, struct bpos pos) |
| { |
| return r->btree == BTREE_ID_inodes |
| ? r->cur_pos.offset == pos.offset |
| : r->cur_pos.inode == pos.inode; |
| } |
| |
| static inline bool snapshot_id_lists_have_common(snapshot_id_list *l, snapshot_id_list *r) |
| { |
| darray_for_each(*l, i) |
| if (snapshot_list_has_id(r, *i)) |
| return true; |
| return false; |
| } |
| |
| static void snapshot_id_list_to_text(struct printbuf *out, snapshot_id_list *s) |
| { |
| bool first = true; |
| darray_for_each(*s, i) { |
| if (!first) |
| prt_char(out, ' '); |
| first = false; |
| prt_printf(out, "%u", *i); |
| } |
| } |
| |
| static int snapshot_tree_reconstruct_next(struct bch_fs *c, struct snapshot_tree_reconstruct *r) |
| { |
| if (r->cur_ids.nr) { |
| darray_for_each(r->trees, i) |
| if (snapshot_id_lists_have_common(i, &r->cur_ids)) { |
| int ret = snapshot_list_merge(c, i, &r->cur_ids); |
| if (ret) |
| return ret; |
| goto out; |
| } |
| darray_push(&r->trees, r->cur_ids); |
| darray_init(&r->cur_ids); |
| } |
| out: |
| r->cur_ids.nr = 0; |
| return 0; |
| } |
| |
| static int get_snapshot_trees(struct bch_fs *c, struct snapshot_tree_reconstruct *r, struct bpos pos) |
| { |
| if (!same_snapshot(r, pos)) |
| snapshot_tree_reconstruct_next(c, r); |
| r->cur_pos = pos; |
| return snapshot_list_add_nodup(c, &r->cur_ids, pos.snapshot); |
| } |
| |
| int bch2_reconstruct_snapshots(struct bch_fs *c) |
| { |
| struct btree_trans *trans = bch2_trans_get(c); |
| struct printbuf buf = PRINTBUF; |
| struct snapshot_tree_reconstruct r = {}; |
| int ret = 0; |
| |
| for (unsigned btree = 0; btree < BTREE_ID_NR; btree++) { |
| if (btree_type_has_snapshots(btree)) { |
| r.btree = btree; |
| |
| ret = for_each_btree_key(trans, iter, btree, POS_MIN, |
| BTREE_ITER_all_snapshots|BTREE_ITER_prefetch, k, ({ |
| get_snapshot_trees(c, &r, k.k->p); |
| })); |
| if (ret) |
| goto err; |
| |
| snapshot_tree_reconstruct_next(c, &r); |
| } |
| } |
| |
| darray_for_each(r.trees, t) { |
| printbuf_reset(&buf); |
| snapshot_id_list_to_text(&buf, t); |
| |
| darray_for_each(*t, id) { |
| if (fsck_err_on(!bch2_snapshot_equiv(c, *id), |
| trans, snapshot_node_missing, |
| "snapshot node %u from tree %s missing, recreate?", *id, buf.buf)) { |
| if (t->nr > 1) { |
| bch_err(c, "cannot reconstruct snapshot trees with multiple nodes"); |
| ret = -BCH_ERR_fsck_repair_unimplemented; |
| goto err; |
| } |
| |
| ret = commit_do(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc, |
| check_snapshot_exists(trans, *id)); |
| if (ret) |
| goto err; |
| } |
| } |
| } |
| fsck_err: |
| err: |
| bch2_trans_put(trans); |
| snapshot_tree_reconstruct_exit(&r); |
| printbuf_exit(&buf); |
| bch_err_fn(c, ret); |
| return ret; |
| } |
| |
| int bch2_check_key_has_snapshot(struct btree_trans *trans, |
| struct btree_iter *iter, |
| struct bkey_s_c k) |
| { |
| struct bch_fs *c = trans->c; |
| struct printbuf buf = PRINTBUF; |
| int ret = 0; |
| |
| if (fsck_err_on(!bch2_snapshot_equiv(c, k.k->p.snapshot), |
| trans, bkey_in_missing_snapshot, |
| "key in missing snapshot %s, delete?", |
| (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) |
| ret = bch2_btree_delete_at(trans, iter, |
| BTREE_UPDATE_internal_snapshot_node) ?: 1; |
| fsck_err: |
| printbuf_exit(&buf); |
| return ret; |
| } |
| |
| /* |
| * Mark a snapshot as deleted, for future cleanup: |
| */ |
| int bch2_snapshot_node_set_deleted(struct btree_trans *trans, u32 id) |
| { |
| struct btree_iter iter; |
| struct bkey_i_snapshot *s; |
| int ret = 0; |
| |
| s = bch2_bkey_get_mut_typed(trans, &iter, |
| BTREE_ID_snapshots, POS(0, id), |
| 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(s); |
| if (unlikely(ret)) { |
| bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), |
| trans->c, "missing snapshot %u", id); |
| return ret; |
| } |
| |
| /* already deleted? */ |
| if (BCH_SNAPSHOT_DELETED(&s->v)) |
| goto err; |
| |
| SET_BCH_SNAPSHOT_DELETED(&s->v, true); |
| SET_BCH_SNAPSHOT_SUBVOL(&s->v, false); |
| s->v.subvol = 0; |
| err: |
| bch2_trans_iter_exit(trans, &iter); |
| return ret; |
| } |
| |
| static inline void normalize_snapshot_child_pointers(struct bch_snapshot *s) |
| { |
| if (le32_to_cpu(s->children[0]) < le32_to_cpu(s->children[1])) |
| swap(s->children[0], s->children[1]); |
| } |
| |
| static int bch2_snapshot_node_delete(struct btree_trans *trans, u32 id) |
| { |
| struct bch_fs *c = trans->c; |
| struct btree_iter iter, p_iter = (struct btree_iter) { NULL }; |
| struct btree_iter c_iter = (struct btree_iter) { NULL }; |
| struct btree_iter tree_iter = (struct btree_iter) { NULL }; |
| struct bkey_s_c_snapshot s; |
| u32 parent_id, child_id; |
| unsigned i; |
| int ret = 0; |
| |
| s = bch2_bkey_get_iter_typed(trans, &iter, BTREE_ID_snapshots, POS(0, id), |
| BTREE_ITER_intent, snapshot); |
| ret = bkey_err(s); |
| bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c, |
| "missing snapshot %u", id); |
| |
| if (ret) |
| goto err; |
| |
| BUG_ON(s.v->children[1]); |
| |
| parent_id = le32_to_cpu(s.v->parent); |
| child_id = le32_to_cpu(s.v->children[0]); |
| |
| if (parent_id) { |
| struct bkey_i_snapshot *parent; |
| |
| parent = bch2_bkey_get_mut_typed(trans, &p_iter, |
| BTREE_ID_snapshots, POS(0, parent_id), |
| 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(parent); |
| bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c, |
| "missing snapshot %u", parent_id); |
| if (unlikely(ret)) |
| goto err; |
| |
| /* find entry in parent->children for node being deleted */ |
| for (i = 0; i < 2; i++) |
| if (le32_to_cpu(parent->v.children[i]) == id) |
| break; |
| |
| if (bch2_fs_inconsistent_on(i == 2, c, |
| "snapshot %u missing child pointer to %u", |
| parent_id, id)) |
| goto err; |
| |
| parent->v.children[i] = cpu_to_le32(child_id); |
| |
| normalize_snapshot_child_pointers(&parent->v); |
| } |
| |
| if (child_id) { |
| struct bkey_i_snapshot *child; |
| |
| child = bch2_bkey_get_mut_typed(trans, &c_iter, |
| BTREE_ID_snapshots, POS(0, child_id), |
| 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(child); |
| bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c, |
| "missing snapshot %u", child_id); |
| if (unlikely(ret)) |
| goto err; |
| |
| child->v.parent = cpu_to_le32(parent_id); |
| |
| if (!child->v.parent) { |
| child->v.skip[0] = 0; |
| child->v.skip[1] = 0; |
| child->v.skip[2] = 0; |
| } |
| } |
| |
| if (!parent_id) { |
| /* |
| * We're deleting the root of a snapshot tree: update the |
| * snapshot_tree entry to point to the new root, or delete it if |
| * this is the last snapshot ID in this tree: |
| */ |
| struct bkey_i_snapshot_tree *s_t; |
| |
| BUG_ON(s.v->children[1]); |
| |
| s_t = bch2_bkey_get_mut_typed(trans, &tree_iter, |
| BTREE_ID_snapshot_trees, POS(0, le32_to_cpu(s.v->tree)), |
| 0, snapshot_tree); |
| ret = PTR_ERR_OR_ZERO(s_t); |
| if (ret) |
| goto err; |
| |
| if (s.v->children[0]) { |
| s_t->v.root_snapshot = s.v->children[0]; |
| } else { |
| s_t->k.type = KEY_TYPE_deleted; |
| set_bkey_val_u64s(&s_t->k, 0); |
| } |
| } |
| |
| ret = bch2_btree_delete_at(trans, &iter, 0); |
| err: |
| bch2_trans_iter_exit(trans, &tree_iter); |
| bch2_trans_iter_exit(trans, &p_iter); |
| bch2_trans_iter_exit(trans, &c_iter); |
| bch2_trans_iter_exit(trans, &iter); |
| return ret; |
| } |
| |
| static int create_snapids(struct btree_trans *trans, u32 parent, u32 tree, |
| u32 *new_snapids, |
| u32 *snapshot_subvols, |
| unsigned nr_snapids) |
| { |
| struct bch_fs *c = trans->c; |
| struct btree_iter iter; |
| struct bkey_i_snapshot *n; |
| struct bkey_s_c k; |
| unsigned i, j; |
| u32 depth = bch2_snapshot_depth(c, parent); |
| int ret; |
| |
| bch2_trans_iter_init(trans, &iter, BTREE_ID_snapshots, |
| POS_MIN, BTREE_ITER_intent); |
| k = bch2_btree_iter_peek(&iter); |
| ret = bkey_err(k); |
| if (ret) |
| goto err; |
| |
| for (i = 0; i < nr_snapids; i++) { |
| k = bch2_btree_iter_prev_slot(&iter); |
| ret = bkey_err(k); |
| if (ret) |
| goto err; |
| |
| if (!k.k || !k.k->p.offset) { |
| ret = -BCH_ERR_ENOSPC_snapshot_create; |
| goto err; |
| } |
| |
| n = bch2_bkey_alloc(trans, &iter, 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(n); |
| if (ret) |
| goto err; |
| |
| n->v.flags = 0; |
| n->v.parent = cpu_to_le32(parent); |
| n->v.subvol = cpu_to_le32(snapshot_subvols[i]); |
| n->v.tree = cpu_to_le32(tree); |
| n->v.depth = cpu_to_le32(depth); |
| n->v.btime.lo = cpu_to_le64(bch2_current_time(c)); |
| n->v.btime.hi = 0; |
| |
| for (j = 0; j < ARRAY_SIZE(n->v.skip); j++) |
| n->v.skip[j] = cpu_to_le32(bch2_snapshot_skiplist_get(c, parent)); |
| |
| bubble_sort(n->v.skip, ARRAY_SIZE(n->v.skip), cmp_le32); |
| SET_BCH_SNAPSHOT_SUBVOL(&n->v, true); |
| |
| ret = __bch2_mark_snapshot(trans, BTREE_ID_snapshots, 0, |
| bkey_s_c_null, bkey_i_to_s_c(&n->k_i), 0); |
| if (ret) |
| goto err; |
| |
| new_snapids[i] = iter.pos.offset; |
| |
| mutex_lock(&c->snapshot_table_lock); |
| snapshot_t_mut(c, new_snapids[i])->equiv = new_snapids[i]; |
| mutex_unlock(&c->snapshot_table_lock); |
| } |
| err: |
| bch2_trans_iter_exit(trans, &iter); |
| return ret; |
| } |
| |
| /* |
| * Create new snapshot IDs as children of an existing snapshot ID: |
| */ |
| static int bch2_snapshot_node_create_children(struct btree_trans *trans, u32 parent, |
| u32 *new_snapids, |
| u32 *snapshot_subvols, |
| unsigned nr_snapids) |
| { |
| struct btree_iter iter; |
| struct bkey_i_snapshot *n_parent; |
| int ret = 0; |
| |
| n_parent = bch2_bkey_get_mut_typed(trans, &iter, |
| BTREE_ID_snapshots, POS(0, parent), |
| 0, snapshot); |
| ret = PTR_ERR_OR_ZERO(n_parent); |
| if (unlikely(ret)) { |
| if (bch2_err_matches(ret, ENOENT)) |
| bch_err(trans->c, "snapshot %u not found", parent); |
| return ret; |
| } |
| |
| if (n_parent->v.children[0] || n_parent->v.children[1]) { |
| bch_err(trans->c, "Trying to add child snapshot nodes to parent that already has children"); |
| ret = -EINVAL; |
| goto err; |
| } |
| |
| ret = create_snapids(trans, parent, le32_to_cpu(n_parent->v.tree), |
| new_snapids, snapshot_subvols, nr_snapids); |
| if (ret) |
| goto err; |
| |
| n_parent->v.children[0] = cpu_to_le32(new_snapids[0]); |
| n_parent->v.children[1] = cpu_to_le32(new_snapids[1]); |
| n_parent->v.subvol = 0; |
| SET_BCH_SNAPSHOT_SUBVOL(&n_parent->v, false); |
| err: |
| bch2_trans_iter_exit(trans, &iter); |
| return ret; |
| } |
| |
| /* |
| * Create a snapshot node that is the root of a new tree: |
| */ |
| static int bch2_snapshot_node_create_tree(struct btree_trans *trans, |
| u32 *new_snapids, |
| u32 *snapshot_subvols, |
| unsigned nr_snapids) |
| { |
| struct bkey_i_snapshot_tree *n_tree; |
| int ret; |
| |
| n_tree = __bch2_snapshot_tree_create(trans); |
| ret = PTR_ERR_OR_ZERO(n_tree) ?: |
| create_snapids(trans, 0, n_tree->k.p.offset, |
| new_snapids, snapshot_subvols, nr_snapids); |
| if (ret) |
| return ret; |
| |
| n_tree->v.master_subvol = cpu_to_le32(snapshot_subvols[0]); |
| n_tree->v.root_snapshot = cpu_to_le32(new_snapids[0]); |
| return 0; |
| } |
| |
| int bch2_snapshot_node_create(struct btree_trans *trans, u32 parent, |
| u32 *new_snapids, |
| u32 *snapshot_subvols, |
| unsigned nr_snapids) |
| { |
| BUG_ON((parent == 0) != (nr_snapids == 1)); |
| BUG_ON((parent != 0) != (nr_snapids == 2)); |
| |
| return parent |
| ? bch2_snapshot_node_create_children(trans, parent, |
| new_snapids, snapshot_subvols, nr_snapids) |
| : bch2_snapshot_node_create_tree(trans, |
| new_snapids, snapshot_subvols, nr_snapids); |
| |
| } |
| |
| /* |
| * If we have an unlinked inode in an internal snapshot node, and the inode |
| * really has been deleted in all child snapshots, how does this get cleaned up? |
| * |
| * first there is the problem of how keys that have been overwritten in all |
| * child snapshots get deleted (unimplemented?), but inodes may perhaps be |
| * special? |
| * |
| * also: unlinked inode in internal snapshot appears to not be getting deleted |
| * correctly if inode doesn't exist in leaf snapshots |
| * |
| * solution: |
| * |
| * for a key in an interior snapshot node that needs work to be done that |
| * requires it to be mutated: iterate over all descendent leaf nodes and copy |
| * that key to snapshot leaf nodes, where we can mutate it |
| */ |
| |
| static int delete_dead_snapshots_process_key(struct btree_trans *trans, |
| struct btree_iter *iter, |
| struct bkey_s_c k, |
| snapshot_id_list *deleted, |
| snapshot_id_list *equiv_seen, |
| struct bpos *last_pos) |
| { |
| int ret = bch2_check_key_has_snapshot(trans, iter, k); |
| if (ret) |
| return ret < 0 ? ret : 0; |
| |
| struct bch_fs *c = trans->c; |
| u32 equiv = bch2_snapshot_equiv(c, k.k->p.snapshot); |
| if (!equiv) /* key for invalid snapshot node, but we chose not to delete */ |
| return 0; |
| |
| if (!bkey_eq(k.k->p, *last_pos)) |
| equiv_seen->nr = 0; |
| |
| if (snapshot_list_has_id(deleted, k.k->p.snapshot)) |
| return bch2_btree_delete_at(trans, iter, |
| BTREE_UPDATE_internal_snapshot_node); |
| |
| if (!bpos_eq(*last_pos, k.k->p) && |
| snapshot_list_has_id(equiv_seen, equiv)) |
| return bch2_btree_delete_at(trans, iter, |
| BTREE_UPDATE_internal_snapshot_node); |
| |
| *last_pos = k.k->p; |
| |
| ret = snapshot_list_add_nodup(c, equiv_seen, equiv); |
| if (ret) |
| return ret; |
| |
| /* |
| * When we have a linear chain of snapshot nodes, we consider |
| * those to form an equivalence class: we're going to collapse |
| * them all down to a single node, and keep the leaf-most node - |
| * which has the same id as the equivalence class id. |
| * |
| * If there are multiple keys in different snapshots at the same |
| * position, we're only going to keep the one in the newest |
| * snapshot (we delete the others above) - the rest have been |
| * overwritten and are redundant, and for the key we're going to keep we |
| * need to move it to the equivalance class ID if it's not there |
| * already. |
| */ |
| if (equiv != k.k->p.snapshot) { |
| struct bkey_i *new = bch2_bkey_make_mut_noupdate(trans, k); |
| int ret = PTR_ERR_OR_ZERO(new); |
| if (ret) |
| return ret; |
| |
| new->k.p.snapshot = equiv; |
| |
| struct btree_iter new_iter; |
| bch2_trans_iter_init(trans, &new_iter, iter->btree_id, new->k.p, |
| BTREE_ITER_all_snapshots| |
| BTREE_ITER_cached| |
| BTREE_ITER_intent); |
| |
| ret = bch2_btree_iter_traverse(&new_iter) ?: |
| bch2_trans_update(trans, &new_iter, new, |
| BTREE_UPDATE_internal_snapshot_node) ?: |
| bch2_btree_delete_at(trans, iter, |
| BTREE_UPDATE_internal_snapshot_node); |
| bch2_trans_iter_exit(trans, &new_iter); |
| if (ret) |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| static int bch2_snapshot_needs_delete(struct btree_trans *trans, struct bkey_s_c k) |
| { |
| struct bkey_s_c_snapshot snap; |
| u32 children[2]; |
| int ret; |
| |
| if (k.k->type != KEY_TYPE_snapshot) |
| return 0; |
| |
| snap = bkey_s_c_to_snapshot(k); |
| if (BCH_SNAPSHOT_DELETED(snap.v) || |
| BCH_SNAPSHOT_SUBVOL(snap.v)) |
| return 0; |
| |
| children[0] = le32_to_cpu(snap.v->children[0]); |
| children[1] = le32_to_cpu(snap.v->children[1]); |
| |
| ret = bch2_snapshot_live(trans, children[0]) ?: |
| bch2_snapshot_live(trans, children[1]); |
| if (ret < 0) |
| return ret; |
| return !ret; |
| } |
| |
| /* |
| * For a given snapshot, if it doesn't have a subvolume that points to it, and |
| * it doesn't have child snapshot nodes - it's now redundant and we can mark it |
| * as deleted. |
| */ |
| static int bch2_delete_redundant_snapshot(struct btree_trans *trans, struct bkey_s_c k) |
| { |
| int ret = bch2_snapshot_needs_delete(trans, k); |
| |
| return ret <= 0 |
| ? ret |
| : bch2_snapshot_node_set_deleted(trans, k.k->p.offset); |
| } |
| |
| static inline u32 bch2_snapshot_nth_parent_skip(struct bch_fs *c, u32 id, u32 n, |
| snapshot_id_list *skip) |
| { |
| rcu_read_lock(); |
| while (snapshot_list_has_id(skip, id)) |
| id = __bch2_snapshot_parent(c, id); |
| |
| while (n--) { |
| do { |
| id = __bch2_snapshot_parent(c, id); |
| } while (snapshot_list_has_id(skip, id)); |
| } |
| rcu_read_unlock(); |
| |
| return id; |
| } |
| |
| static int bch2_fix_child_of_deleted_snapshot(struct btree_trans *trans, |
| struct btree_iter *iter, struct bkey_s_c k, |
| snapshot_id_list *deleted) |
| { |
| struct bch_fs *c = trans->c; |
| u32 nr_deleted_ancestors = 0; |
| struct bkey_i_snapshot *s; |
| int ret; |
| |
| if (k.k->type != KEY_TYPE_snapshot) |
| return 0; |
| |
| if (snapshot_list_has_id(deleted, k.k->p.offset)) |
| return 0; |
| |
| s = bch2_bkey_make_mut_noupdate_typed(trans, k, snapshot); |
| ret = PTR_ERR_OR_ZERO(s); |
| if (ret) |
| return ret; |
| |
| darray_for_each(*deleted, i) |
| nr_deleted_ancestors += bch2_snapshot_is_ancestor(c, s->k.p.offset, *i); |
| |
| if (!nr_deleted_ancestors) |
| return 0; |
| |
| le32_add_cpu(&s->v.depth, -nr_deleted_ancestors); |
| |
| if (!s->v.depth) { |
| s->v.skip[0] = 0; |
| s->v.skip[1] = 0; |
| s->v.skip[2] = 0; |
| } else { |
| u32 depth = le32_to_cpu(s->v.depth); |
| u32 parent = bch2_snapshot_parent(c, s->k.p.offset); |
| |
| for (unsigned j = 0; j < ARRAY_SIZE(s->v.skip); j++) { |
| u32 id = le32_to_cpu(s->v.skip[j]); |
| |
| if (snapshot_list_has_id(deleted, id)) { |
| id = bch2_snapshot_nth_parent_skip(c, |
| parent, |
| depth > 1 |
| ? get_random_u32_below(depth - 1) |
| : 0, |
| deleted); |
| s->v.skip[j] = cpu_to_le32(id); |
| } |
| } |
| |
| bubble_sort(s->v.skip, ARRAY_SIZE(s->v.skip), cmp_le32); |
| } |
| |
| return bch2_trans_update(trans, iter, &s->k_i, 0); |
| } |
| |
| int bch2_delete_dead_snapshots(struct bch_fs *c) |
| { |
| struct btree_trans *trans; |
| snapshot_id_list deleted = { 0 }; |
| snapshot_id_list deleted_interior = { 0 }; |
| int ret = 0; |
| |
| if (!test_and_clear_bit(BCH_FS_need_delete_dead_snapshots, &c->flags)) |
| return 0; |
| |
| trans = bch2_trans_get(c); |
| |
| /* |
| * For every snapshot node: If we have no live children and it's not |
| * pointed to by a subvolume, delete it: |
| */ |
| ret = for_each_btree_key_commit(trans, iter, BTREE_ID_snapshots, |
| POS_MIN, 0, k, |
| NULL, NULL, 0, |
| bch2_delete_redundant_snapshot(trans, k)); |
| bch_err_msg(c, ret, "deleting redundant snapshots"); |
| if (ret) |
| goto err; |
| |
| ret = for_each_btree_key(trans, iter, BTREE_ID_snapshots, |
| POS_MIN, 0, k, |
| bch2_snapshot_set_equiv(trans, k)); |
| bch_err_msg(c, ret, "in bch2_snapshots_set_equiv"); |
| if (ret) |
| goto err; |
| |
| ret = for_each_btree_key(trans, iter, BTREE_ID_snapshots, |
| POS_MIN, 0, k, ({ |
| if (k.k->type != KEY_TYPE_snapshot) |
| continue; |
| |
| BCH_SNAPSHOT_DELETED(bkey_s_c_to_snapshot(k).v) |
| ? snapshot_list_add(c, &deleted, k.k->p.offset) |
| : 0; |
| })); |
| bch_err_msg(c, ret, "walking snapshots"); |
| if (ret) |
| goto err; |
| |
| for (unsigned btree = 0; btree < BTREE_ID_NR; btree++) { |
| struct bpos last_pos = POS_MIN; |
| snapshot_id_list equiv_seen = { 0 }; |
| struct disk_reservation res = { 0 }; |
| |
| if (!btree_type_has_snapshots(btree)) |
| continue; |
| |
| ret = for_each_btree_key_commit(trans, iter, |
| btree, POS_MIN, |
| BTREE_ITER_prefetch|BTREE_ITER_all_snapshots, k, |
| &res, NULL, BCH_TRANS_COMMIT_no_enospc, |
| delete_dead_snapshots_process_key(trans, &iter, k, &deleted, |
| &equiv_seen, &last_pos)); |
| |
| bch2_disk_reservation_put(c, &res); |
| darray_exit(&equiv_seen); |
| |
| bch_err_msg(c, ret, "deleting keys from dying snapshots"); |
| if (ret) |
| goto err; |
| } |
| |
| bch2_trans_unlock(trans); |
| down_write(&c->snapshot_create_lock); |
| |
| ret = for_each_btree_key(trans, iter, BTREE_ID_snapshots, |
| POS_MIN, 0, k, ({ |
| u32 snapshot = k.k->p.offset; |
| u32 equiv = bch2_snapshot_equiv(c, snapshot); |
| |
| equiv != snapshot |
| ? snapshot_list_add(c, &deleted_interior, snapshot) |
| : 0; |
| })); |
| |
| bch_err_msg(c, ret, "walking snapshots"); |
| if (ret) |
| goto err_create_lock; |
| |
| /* |
| * Fixing children of deleted snapshots can't be done completely |
| * atomically, if we crash between here and when we delete the interior |
| * nodes some depth fields will be off: |
| */ |
| ret = for_each_btree_key_commit(trans, iter, BTREE_ID_snapshots, POS_MIN, |
| BTREE_ITER_intent, k, |
| NULL, NULL, BCH_TRANS_COMMIT_no_enospc, |
| bch2_fix_child_of_deleted_snapshot(trans, &iter, k, &deleted_interior)); |
| if (ret) |
| goto err_create_lock; |
| |
| darray_for_each(deleted, i) { |
| ret = commit_do(trans, NULL, NULL, 0, |
| bch2_snapshot_node_delete(trans, *i)); |
| bch_err_msg(c, ret, "deleting snapshot %u", *i); |
| if (ret) |
| goto err_create_lock; |
| } |
| |
| darray_for_each(deleted_interior, i) { |
| ret = commit_do(trans, NULL, NULL, 0, |
| bch2_snapshot_node_delete(trans, *i)); |
| bch_err_msg(c, ret, "deleting snapshot %u", *i); |
| if (ret) |
| goto err_create_lock; |
| } |
| err_create_lock: |
| up_write(&c->snapshot_create_lock); |
| err: |
| darray_exit(&deleted_interior); |
| darray_exit(&deleted); |
| bch2_trans_put(trans); |
| bch_err_fn(c, ret); |
| return ret; |
| } |
| |
| void bch2_delete_dead_snapshots_work(struct work_struct *work) |
| { |
| struct bch_fs *c = container_of(work, struct bch_fs, snapshot_delete_work); |
| |
| set_worker_desc("bcachefs-delete-dead-snapshots/%s", c->name); |
| |
| bch2_delete_dead_snapshots(c); |
| bch2_write_ref_put(c, BCH_WRITE_REF_delete_dead_snapshots); |
| } |
| |
| void bch2_delete_dead_snapshots_async(struct bch_fs *c) |
| { |
| if (bch2_write_ref_tryget(c, BCH_WRITE_REF_delete_dead_snapshots) && |
| !queue_work(c->write_ref_wq, &c->snapshot_delete_work)) |
| bch2_write_ref_put(c, BCH_WRITE_REF_delete_dead_snapshots); |
| } |
| |
| int __bch2_key_has_snapshot_overwrites(struct btree_trans *trans, |
| enum btree_id id, |
| struct bpos pos) |
| { |
| struct bch_fs *c = trans->c; |
| struct btree_iter iter; |
| struct bkey_s_c k; |
| int ret; |
| |
| bch2_trans_iter_init(trans, &iter, id, pos, |
| BTREE_ITER_not_extents| |
| BTREE_ITER_all_snapshots); |
| while (1) { |
| k = bch2_btree_iter_prev(&iter); |
| ret = bkey_err(k); |
| if (ret) |
| break; |
| |
| if (!k.k) |
| break; |
| |
| if (!bkey_eq(pos, k.k->p)) |
| break; |
| |
| if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, pos.snapshot)) { |
| ret = 1; |
| break; |
| } |
| } |
| bch2_trans_iter_exit(trans, &iter); |
| |
| return ret; |
| } |
| |
| static u32 bch2_snapshot_smallest_child(struct bch_fs *c, u32 id) |
| { |
| const struct snapshot_t *s = snapshot_t(c, id); |
| |
| return s->children[1] ?: s->children[0]; |
| } |
| |
| static u32 bch2_snapshot_smallest_descendent(struct bch_fs *c, u32 id) |
| { |
| u32 child; |
| |
| while ((child = bch2_snapshot_smallest_child(c, id))) |
| id = child; |
| return id; |
| } |
| |
| static int bch2_propagate_key_to_snapshot_leaf(struct btree_trans *trans, |
| enum btree_id btree, |
| struct bkey_s_c interior_k, |
| u32 leaf_id, struct bpos *new_min_pos) |
| { |
| struct btree_iter iter; |
| struct bpos pos = interior_k.k->p; |
| struct bkey_s_c k; |
| struct bkey_i *new; |
| int ret; |
| |
| pos.snapshot = leaf_id; |
| |
| bch2_trans_iter_init(trans, &iter, btree, pos, BTREE_ITER_intent); |
| k = bch2_btree_iter_peek_slot(&iter); |
| ret = bkey_err(k); |
| if (ret) |
| goto out; |
| |
| /* key already overwritten in this snapshot? */ |
| if (k.k->p.snapshot != interior_k.k->p.snapshot) |
| goto out; |
| |
| if (bpos_eq(*new_min_pos, POS_MIN)) { |
| *new_min_pos = k.k->p; |
| new_min_pos->snapshot = leaf_id; |
| } |
| |
| new = bch2_bkey_make_mut_noupdate(trans, interior_k); |
| ret = PTR_ERR_OR_ZERO(new); |
| if (ret) |
| goto out; |
| |
| new->k.p.snapshot = leaf_id; |
| ret = bch2_trans_update(trans, &iter, new, 0); |
| out: |
| bch2_set_btree_iter_dontneed(&iter); |
| bch2_trans_iter_exit(trans, &iter); |
| return ret; |
| } |
| |
| int bch2_propagate_key_to_snapshot_leaves(struct btree_trans *trans, |
| enum btree_id btree, |
| struct bkey_s_c k, |
| struct bpos *new_min_pos) |
| { |
| struct bch_fs *c = trans->c; |
| struct bkey_buf sk; |
| u32 restart_count = trans->restart_count; |
| int ret = 0; |
| |
| bch2_bkey_buf_init(&sk); |
| bch2_bkey_buf_reassemble(&sk, c, k); |
| k = bkey_i_to_s_c(sk.k); |
| |
| *new_min_pos = POS_MIN; |
| |
| for (u32 id = bch2_snapshot_smallest_descendent(c, k.k->p.snapshot); |
| id < k.k->p.snapshot; |
| id++) { |
| if (!bch2_snapshot_is_ancestor(c, id, k.k->p.snapshot) || |
| !bch2_snapshot_is_leaf(c, id)) |
| continue; |
| again: |
| ret = btree_trans_too_many_iters(trans) ?: |
| bch2_propagate_key_to_snapshot_leaf(trans, btree, k, id, new_min_pos) ?: |
| bch2_trans_commit(trans, NULL, NULL, 0); |
| if (ret && bch2_err_matches(ret, BCH_ERR_transaction_restart)) { |
| bch2_trans_begin(trans); |
| goto again; |
| } |
| |
| if (ret) |
| break; |
| } |
| |
| bch2_bkey_buf_exit(&sk, c); |
| |
| return ret ?: trans_was_restarted(trans, restart_count); |
| } |
| |
| static int bch2_check_snapshot_needs_deletion(struct btree_trans *trans, struct bkey_s_c k) |
| { |
| struct bch_fs *c = trans->c; |
| struct bkey_s_c_snapshot snap; |
| int ret = 0; |
| |
| if (k.k->type != KEY_TYPE_snapshot) |
| return 0; |
| |
| snap = bkey_s_c_to_snapshot(k); |
| if (BCH_SNAPSHOT_DELETED(snap.v) || |
| bch2_snapshot_equiv(c, k.k->p.offset) != k.k->p.offset || |
| (ret = bch2_snapshot_needs_delete(trans, k)) > 0) { |
| set_bit(BCH_FS_need_delete_dead_snapshots, &c->flags); |
| return 0; |
| } |
| |
| return ret; |
| } |
| |
| int bch2_snapshots_read(struct bch_fs *c) |
| { |
| int ret = bch2_trans_run(c, |
| for_each_btree_key(trans, iter, BTREE_ID_snapshots, |
| POS_MIN, 0, k, |
| __bch2_mark_snapshot(trans, BTREE_ID_snapshots, 0, bkey_s_c_null, k, 0) ?: |
| bch2_snapshot_set_equiv(trans, k) ?: |
| bch2_check_snapshot_needs_deletion(trans, k)) ?: |
| for_each_btree_key(trans, iter, BTREE_ID_snapshots, |
| POS_MIN, 0, k, |
| (set_is_ancestor_bitmap(c, k.k->p.offset), 0))); |
| bch_err_fn(c, ret); |
| |
| /* |
| * It's important that we check if we need to reconstruct snapshots |
| * before going RW, so we mark that pass as required in the superblock - |
| * otherwise, we could end up deleting keys with missing snapshot nodes |
| * instead |
| */ |
| BUG_ON(!test_bit(BCH_FS_new_fs, &c->flags) && |
| test_bit(BCH_FS_may_go_rw, &c->flags)); |
| |
| if (bch2_err_matches(ret, EIO) || |
| (c->sb.btrees_lost_data & BIT_ULL(BTREE_ID_snapshots))) |
| ret = bch2_run_explicit_recovery_pass_persistent(c, BCH_RECOVERY_PASS_reconstruct_snapshots); |
| |
| return ret; |
| } |
| |
| void bch2_fs_snapshots_exit(struct bch_fs *c) |
| { |
| kvfree(rcu_dereference_protected(c->snapshots, true)); |
| } |