diff options
Diffstat (limited to 'fs/bcachefs/snapshot.c')
| -rw-r--r-- | fs/bcachefs/snapshot.c | 1881 |
1 files changed, 0 insertions, 1881 deletions
diff --git a/fs/bcachefs/snapshot.c b/fs/bcachefs/snapshot.c deleted file mode 100644 index 24023d6a9698..000000000000 --- a/fs/bcachefs/snapshot.c +++ /dev/null @@ -1,1881 +0,0 @@ -// 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_invalid(struct bch_fs *c, struct bkey_s_c k, - enum bch_validate_flags flags, - struct printbuf *err) -{ - 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, err, - 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_invalid(struct bch_fs *c, struct bkey_s_c k, - enum bch_validate_flags flags, - struct printbuf *err) -{ - 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, err, - 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, err, - 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, err, - snapshot_children_not_normalized, - "children not normalized"); - - bkey_fsck_err_on(s.v->children[0] && s.v->children[0] == s.v->children[1], c, err, - 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, err, - 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, err, - 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, err, - 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; - - while (id) { - s = snapshot_t(c, id)->subvol; - - if (s && (!subvol || s < subvol)) - subvol = s; - - id = bch2_snapshot_tree_next(c, id); - } - - 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), - c, 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, - c, 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), - c, 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), - c, 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, - c, 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, c, 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, - c, 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, c, 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), - c, 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), c, - 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_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)); -} |