+++ /dev/null
-// 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 "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 bkey_invalid_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 bch_fs *c, u32 id, u32 ancestor)
-{
- struct snapshot_table *t;
-
- rcu_read_lock();
- t = rcu_dereference(c->snapshots);
-
- while (id && id < ancestor)
- id = __snapshot_t(t, id)->parent;
- rcu_read_unlock();
-
- return id == ancestor;
-}
-
-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->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;
-}
-
-bool __bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor)
-{
- struct snapshot_table *t;
- bool ret;
-
- EBUG_ON(c->recovery_pass_done <= BCH_RECOVERY_PASS_check_snapshots);
-
- rcu_read_lock();
- t = rcu_dereference(c->snapshots);
-
- while (id && id < ancestor - IS_ANCESTOR_BITMAP)
- id = get_ancestor_below(t, id, ancestor);
-
- if (id && id < ancestor) {
- ret = test_bit(ancestor - id - 1, __snapshot_t(t, id)->is_ancestor);
-
- EBUG_ON(ret != bch2_snapshot_is_ancestor_early(c, id, ancestor));
- } else {
- ret = id == ancestor;
- }
-
- 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;
- size_t new_size;
- struct snapshot_table *new, *old;
-
- new_size = max(16UL, roundup_pow_of_two(idx + 1));
-
- new = kvzalloc(struct_size(new, s, new_size), GFP_KERNEL);
- if (!new)
- return NULL;
-
- old = rcu_dereference_protected(c->snapshots, true);
- if (old)
- memcpy(new->s,
- rcu_dereference_protected(c->snapshots, true)->s,
- sizeof(new->s[0]) * c->snapshot_table_size);
-
- rcu_assign_pointer(c->snapshots, new);
- c->snapshot_table_size = new_size;
- kvfree_rcu_mightsleep(old);
-
- return &rcu_dereference_protected(c->snapshots, true)->s[idx];
-}
-
-static inline struct snapshot_t *snapshot_t_mut(struct bch_fs *c, u32 id)
-{
- size_t idx = U32_MAX - id;
-
- lockdep_assert_held(&c->snapshot_table_lock);
-
- if (likely(idx < c->snapshot_table_size))
- return &rcu_dereference_protected(c->snapshots, true)->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 bkey_invalid_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,
- unsigned 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,
- unsigned 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_early(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);
- 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;
- bool should_have_subvol;
- u32 i, id;
- int ret = 0;
-
- if (k.k->type != KEY_TYPE_snapshot)
- return 0;
-
- memset(&s, 0, sizeof(s));
- memcpy(&s, k.v, 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;
- }
- }
-
- 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;
-}
-
-/*
- * 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);
-
- 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 snapshot_delete_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)
-{
- struct bch_fs *c = trans->c;
- u32 equiv = bch2_snapshot_equiv(c, k.k->p.snapshot);
-
- if (!bkey_eq(k.k->p, *last_pos))
- equiv_seen->nr = 0;
- *last_pos = k.k->p;
-
- if (snapshot_list_has_id(deleted, k.k->p.snapshot) ||
- snapshot_list_has_id(equiv_seen, equiv)) {
- return bch2_btree_delete_at(trans, iter,
- BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
- } else {
- return snapshot_list_add(c, equiv_seen, equiv);
- }
-}
-
-static int move_key_to_correct_snapshot(struct btree_trans *trans,
- struct btree_iter *iter,
- struct bkey_s_c k)
-{
- struct bch_fs *c = trans->c;
- u32 equiv = bch2_snapshot_equiv(c, k.k->p.snapshot);
-
- /*
- * 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 - 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);
- struct btree_iter new_iter;
- int ret;
-
- ret = PTR_ERR_OR_ZERO(new);
- if (ret)
- return ret;
-
- new->k.p.snapshot = equiv;
-
- 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 };
- u32 id;
- int ret = 0;
-
- if (!test_and_clear_bit(BCH_FS_need_delete_dead_snapshots, &c->flags))
- return 0;
-
- if (!test_bit(BCH_FS_started, &c->flags)) {
- ret = bch2_fs_read_write_early(c);
- bch_err_msg(c, ret, "deleting dead snapshots: error going rw");
- if (ret)
- return ret;
- }
-
- 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 (id = 0; id < BTREE_ID_NR; id++) {
- struct bpos last_pos = POS_MIN;
- snapshot_id_list equiv_seen = { 0 };
- struct disk_reservation res = { 0 };
-
- if (!btree_type_has_snapshots(id))
- continue;
-
- /*
- * deleted inodes btree is maintained by a trigger on the inodes
- * btree - no work for us to do here, and it's not safe to scan
- * it because we'll see out of date keys due to the btree write
- * buffer:
- */
- if (id == BTREE_ID_deleted_inodes)
- continue;
-
- ret = for_each_btree_key_commit(trans, iter,
- id, POS_MIN,
- BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS, k,
- &res, NULL, BCH_TRANS_COMMIT_no_enospc,
- snapshot_delete_key(trans, &iter, k, &deleted, &equiv_seen, &last_pos)) ?:
- for_each_btree_key_commit(trans, iter,
- id, POS_MIN,
- BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS, k,
- &res, NULL, BCH_TRANS_COMMIT_no_enospc,
- move_key_to_correct_snapshot(trans, &iter, k));
-
- 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);
-
- 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);
- return ret;
-}
-
-void bch2_fs_snapshots_exit(struct bch_fs *c)
-{
- kfree(rcu_dereference_protected(c->snapshots, true));
-}
projects / bcachefs-tools-debian / blobdiff