sb-members.o \
siphash.o \
six.o \
+ snapshot.o \
subvolume.o \
super.o \
super-io.o \
__le32 flags;
__le32 snapshot;
__le64 inode;
+ /*
+ * Snapshot subvolumes form a tree, separate from the snapshot nodes
+ * tree - if this subvolume is a snapshot, this is the ID of the
+ * subvolume it was created from:
+ */
__le32 parent;
__le32 pad;
bch_le128 otime;
#include "lru.h"
#include "quota.h"
#include "reflink.h"
+#include "snapshot.h"
#include "subvolume.h"
#include "xattr.h"
#include "extents.h"
#include "journal.h"
#include "replicas.h"
-#include "subvolume.h"
+#include "snapshot.h"
#include "trace.h"
#include <linux/random.h>
#include "journal.h"
#include "journal_reclaim.h"
#include "replicas.h"
-#include "subvolume.h"
+#include "snapshot.h"
#include <linux/prefetch.h>
#include "error.h"
#include "extents.h"
#include "keylist.h"
-#include "subvolume.h"
+#include "snapshot.h"
#include "trace.h"
static inline int btree_insert_entry_cmp(const struct btree_insert_entry *l,
#include "journal.h"
#include "keylist.h"
#include "quota.h"
+#include "snapshot.h"
#include "super.h"
#include "xattr.h"
#include "inode.h"
#include "keylist.h"
#include "recovery.h"
-#include "subvolume.h"
+#include "snapshot.h"
#include "super.h"
#include "xattr.h"
#include "extent_update.h"
#include "inode.h"
#include "str_hash.h"
+#include "snapshot.h"
#include "subvolume.h"
#include "varint.h"
#include "error.h"
#include "inode.h"
#include "quota.h"
-#include "subvolume.h"
+#include "snapshot.h"
#include "super-io.h"
static const char * const bch2_quota_types[] = {
#include "recovery.h"
#include "replicas.h"
#include "sb-clean.h"
+#include "snapshot.h"
#include "subvolume.h"
#include "super-io.h"
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#include "bcachefs.h"
+#include "btree_key_cache.h"
+#include "btree_update.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(const struct bch_fs *c, struct bkey_s_c k,
+ enum bkey_invalid_flags flags,
+ struct printbuf *err)
+{
+ if (bkey_gt(k.k->p, POS(0, U32_MAX)) ||
+ bkey_lt(k.k->p, POS(0, 1))) {
+ prt_printf(err, "bad pos");
+ return -BCH_ERR_invalid_bkey;
+ }
+
+ return 0;
+}
+
+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 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->curr_recovery_pass <= 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);
+
+ ret = id && id < ancestor
+ ? test_bit(ancestor - id - 1, __snapshot_t(t, id)->is_ancestor)
+ : id == ancestor;
+ rcu_read_unlock();
+
+ return ret;
+}
+
+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;
+}
+
+struct snapshot_t_free_rcu {
+ struct rcu_head rcu;
+ struct snapshot_table *t;
+};
+
+static void snapshot_t_free_rcu(struct rcu_head *rcu)
+{
+ struct snapshot_t_free_rcu *free_rcu =
+ container_of(rcu, struct snapshot_t_free_rcu, rcu);
+
+ kvfree(free_rcu->t);
+ kfree(free_rcu);
+}
+
+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;
+ if (old) {
+ struct snapshot_t_free_rcu *rcu =
+ kmalloc(sizeof(*rcu), GFP_KERNEL|__GFP_NOFAIL);
+
+ rcu->t = old;
+ call_rcu(&rcu->rcu, snapshot_t_free_rcu);
+ }
+
+ 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(const 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;
+
+ if (bkey_gt(k.k->p, POS(0, U32_MAX)) ||
+ bkey_lt(k.k->p, POS(0, 1))) {
+ prt_printf(err, "bad pos");
+ return -BCH_ERR_invalid_bkey;
+ }
+
+ s = bkey_s_c_to_snapshot(k);
+
+ id = le32_to_cpu(s.v->parent);
+ if (id && id <= k.k->p.offset) {
+ prt_printf(err, "bad parent node (%u <= %llu)",
+ id, k.k->p.offset);
+ return -BCH_ERR_invalid_bkey;
+ }
+
+ if (le32_to_cpu(s.v->children[0]) < le32_to_cpu(s.v->children[1])) {
+ prt_printf(err, "children not normalized");
+ return -BCH_ERR_invalid_bkey;
+ }
+
+ if (s.v->children[0] &&
+ s.v->children[0] == s.v->children[1]) {
+ prt_printf(err, "duplicate child nodes");
+ return -BCH_ERR_invalid_bkey;
+ }
+
+ for (i = 0; i < 2; i++) {
+ id = le32_to_cpu(s.v->children[i]);
+
+ if (id >= k.k->p.offset) {
+ prt_printf(err, "bad child node (%u >= %llu)",
+ id, k.k->p.offset);
+ return -BCH_ERR_invalid_bkey;
+ }
+ }
+
+ if (bkey_val_bytes(k.k) > offsetof(struct bch_snapshot, skip)) {
+ if (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])) {
+ prt_printf(err, "skiplist not normalized");
+ return -BCH_ERR_invalid_bkey;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(s.v->skip); i++) {
+ id = le32_to_cpu(s.v->skip[i]);
+
+ if (!id != !s.v->parent ||
+ (s.v->parent &&
+ id <= k.k->p.offset)) {
+ prt_printf(err, "bad skiplist node %u)", id);
+ return -BCH_ERR_invalid_bkey;
+ }
+ }
+ }
+
+ return 0;
+}
+
+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);
+ u32 parent = id;
+
+ 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;
+ }
+
+ while ((parent = bch2_snapshot_parent_early(c, parent)) &&
+ parent - id - 1 < IS_ANCESTOR_BITMAP)
+ __set_bit(parent - id - 1, t->is_ancestor);
+
+ if (BCH_SNAPSHOT_DELETED(s.v)) {
+ set_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags);
+ c->recovery_passes_explicit |= BIT_ULL(BCH_RECOVERY_PASS_delete_dead_snapshots);
+ }
+ } else {
+ memset(t, 0, sizeof(*t));
+ }
+err:
+ mutex_unlock(&c->snapshot_table_lock);
+ return ret;
+}
+
+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);
+}
+
+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).
+ */
+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;
+ struct bkey_s_c_subvolume s;
+ 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;
+
+ 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 *s;
+
+ *subvol_id = bch2_snapshot_tree_oldest_subvol(c, snapshot_root);
+
+ s = bch2_bkey_get_mut_typed(trans, &iter,
+ BTREE_ID_subvolumes, POS(0, *subvol_id),
+ 0, subvolume);
+ ret = PTR_ERR_OR_ZERO(s);
+ if (ret)
+ return ret;
+
+ SET_BCH_SUBVOLUME_SNAP(&s->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 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 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 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 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)
+{
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ int ret;
+
+ ret = bch2_trans_run(c,
+ for_each_btree_key_commit(&trans, iter,
+ BTREE_ID_snapshot_trees, POS_MIN,
+ BTREE_ITER_PREFETCH, k,
+ NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
+ check_snapshot_tree(&trans, &iter, k)));
+
+ if (ret)
+ bch_err(c, "error %i checking snapshot trees", 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, struct bch_snapshot s)
+{
+ struct bch_snapshot a;
+ unsigned i;
+ int ret;
+
+ for (i = 0; i < 3; i++) {
+ if (!s.parent != !s.skip[i])
+ return false;
+
+ if (!s.parent)
+ continue;
+
+ ret = bch2_snapshot_lookup(trans, le32_to_cpu(s.skip[i]), &a);
+ if (bch2_err_matches(ret, ENOENT))
+ return false;
+ if (ret)
+ return ret;
+
+ if (a.tree != s.tree)
+ 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 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 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 (le32_to_cpu(s.depth) != real_depth &&
+ (c->sb.version_upgrade_complete < bcachefs_metadata_version_snapshot_skiplists ||
+ fsck_err(c, "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, s);
+ if (ret < 0)
+ goto err;
+
+ if (!ret &&
+ (c->sb.version_upgrade_complete < bcachefs_metadata_version_snapshot_skiplists ||
+ fsck_err(c, "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)
+{
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ int ret;
+
+ /*
+ * We iterate backwards as checking/fixing the depth field requires that
+ * the parent's depth already be correct:
+ */
+ ret = bch2_trans_run(c,
+ for_each_btree_key_reverse_commit(&trans, iter,
+ BTREE_ID_snapshots, POS_MAX,
+ BTREE_ITER_PREFETCH, k,
+ NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
+ check_snapshot(&trans, &iter, k)));
+ if (ret)
+ 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 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 tree_iter = (struct btree_iter) { NULL };
+ struct bkey_s_c_snapshot s;
+ u32 parent_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(!BCH_SNAPSHOT_DELETED(s.v));
+ parent_id = le32_to_cpu(s.v->parent);
+
+ 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);
+ if (unlikely(ret)) {
+ bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
+ "missing snapshot %u", parent_id);
+ goto err;
+ }
+
+ for (i = 0; i < 2; i++)
+ if (le32_to_cpu(parent->v.children[i]) == id)
+ break;
+
+ if (i == 2)
+ bch_err(c, "snapshot %u missing child pointer to %u",
+ parent_id, id);
+ else
+ parent->v.children[i] = 0;
+
+ if (le32_to_cpu(parent->v.children[0]) <
+ le32_to_cpu(parent->v.children[1]))
+ swap(parent->v.children[0],
+ parent->v.children[1]);
+ } else {
+ /*
+ * 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, &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;
+ }
+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
+ */
+
+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);
+ }
+}
+
+/*
+ * 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 btree_iter *iter,
+ 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;
+
+ if (!ret)
+ return bch2_snapshot_node_set_deleted(trans, k.k->p.offset);
+ return 0;
+}
+
+int bch2_delete_dead_snapshots(struct bch_fs *c)
+{
+ struct btree_trans trans;
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ struct bkey_s_c_snapshot snap;
+ snapshot_id_list deleted = { 0 };
+ u32 i, id;
+ int ret = 0;
+
+ if (!test_bit(BCH_FS_STARTED, &c->flags)) {
+ ret = bch2_fs_read_write_early(c);
+ if (ret) {
+ bch_err(c, "error deleleting dead snapshots: error going rw: %s", bch2_err_str(ret));
+ return ret;
+ }
+ }
+
+ bch2_trans_init(&trans, c, 0, 0);
+
+ /*
+ * 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, &iter, k));
+ if (ret) {
+ bch_err(c, "error deleting redundant snapshots: %s", bch2_err_str(ret));
+ goto err;
+ }
+
+ for_each_btree_key2(&trans, iter, BTREE_ID_snapshots,
+ POS_MIN, 0, k,
+ bch2_snapshot_set_equiv(&trans, k));
+ if (ret) {
+ bch_err(c, "error in bch2_snapshots_set_equiv: %s", bch2_err_str(ret));
+ goto err;
+ }
+
+ for_each_btree_key(&trans, iter, BTREE_ID_snapshots,
+ POS_MIN, 0, k, ret) {
+ if (k.k->type != KEY_TYPE_snapshot)
+ continue;
+
+ snap = bkey_s_c_to_snapshot(k);
+ if (BCH_SNAPSHOT_DELETED(snap.v)) {
+ ret = snapshot_list_add(c, &deleted, k.k->p.offset);
+ if (ret)
+ break;
+ }
+ }
+ bch2_trans_iter_exit(&trans, &iter);
+
+ if (ret) {
+ bch_err_msg(c, ret, "walking snapshots");
+ goto err;
+ }
+
+ for (id = 0; id < BTREE_ID_NR; id++) {
+ struct bpos last_pos = POS_MIN;
+ snapshot_id_list equiv_seen = { 0 };
+
+ if (!btree_type_has_snapshots(id))
+ continue;
+
+ ret = for_each_btree_key_commit(&trans, iter,
+ id, POS_MIN,
+ BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS, k,
+ NULL, NULL, BTREE_INSERT_NOFAIL,
+ snapshot_delete_key(&trans, &iter, k, &deleted, &equiv_seen, &last_pos));
+
+ darray_exit(&equiv_seen);
+
+ if (ret) {
+ bch_err_msg(c, ret, "deleting keys from dying snapshots");
+ goto err;
+ }
+ }
+
+ for (i = 0; i < deleted.nr; i++) {
+ u32 node_to_delete = deleted.data[i];
+
+ ret = commit_do(&trans, NULL, NULL, 0,
+ bch2_snapshot_node_delete(&trans, node_to_delete));
+ if (ret) {
+ bch_err_msg(c, ret, "deleting snapshot %u", node_to_delete);
+ goto err;
+ }
+ }
+
+ clear_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags);
+err:
+ darray_exit(&deleted);
+ bch2_trans_exit(&trans);
+ if (ret)
+ 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);
+
+ if (test_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags))
+ 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_delete_dead_snapshots_hook(struct btree_trans *trans,
+ struct btree_trans_commit_hook *h)
+{
+ struct bch_fs *c = trans->c;
+
+ set_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags);
+
+ if (c->curr_recovery_pass <= BCH_RECOVERY_PASS_delete_dead_snapshots)
+ return 0;
+
+ bch2_delete_dead_snapshots_async(c);
+ return 0;
+}
+
+int bch2_snapshots_read(struct bch_fs *c)
+{
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ int ret = 0;
+
+ ret = bch2_trans_run(c,
+ for_each_btree_key2(&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)));
+ if (ret)
+ bch_err_fn(c, ret);
+ return ret;
+}
+
+void bch2_fs_snapshots_exit(struct bch_fs *c)
+{
+ kfree(rcu_dereference_protected(c->snapshots, true));
+}
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_SNAPSHOT_H
+#define _BCACHEFS_SNAPSHOT_H
+
+enum bkey_invalid_flags;
+
+void bch2_snapshot_tree_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
+int bch2_snapshot_tree_invalid(const struct bch_fs *, struct bkey_s_c,
+ enum bkey_invalid_flags, struct printbuf *);
+
+#define bch2_bkey_ops_snapshot_tree ((struct bkey_ops) { \
+ .key_invalid = bch2_snapshot_tree_invalid, \
+ .val_to_text = bch2_snapshot_tree_to_text, \
+ .min_val_size = 8, \
+})
+
+struct bkey_i_snapshot_tree *__bch2_snapshot_tree_create(struct btree_trans *);
+
+int bch2_snapshot_tree_lookup(struct btree_trans *, u32, struct bch_snapshot_tree *);
+
+void bch2_snapshot_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
+int bch2_snapshot_invalid(const struct bch_fs *, struct bkey_s_c,
+ enum bkey_invalid_flags, struct printbuf *);
+int bch2_mark_snapshot(struct btree_trans *, enum btree_id, unsigned,
+ struct bkey_s_c, struct bkey_s_c, unsigned);
+
+#define bch2_bkey_ops_snapshot ((struct bkey_ops) { \
+ .key_invalid = bch2_snapshot_invalid, \
+ .val_to_text = bch2_snapshot_to_text, \
+ .atomic_trigger = bch2_mark_snapshot, \
+ .min_val_size = 24, \
+})
+
+static inline struct snapshot_t *__snapshot_t(struct snapshot_table *t, u32 id)
+{
+ return &t->s[U32_MAX - id];
+}
+
+static inline const struct snapshot_t *snapshot_t(struct bch_fs *c, u32 id)
+{
+ return __snapshot_t(rcu_dereference(c->snapshots), id);
+}
+
+static inline u32 bch2_snapshot_tree(struct bch_fs *c, u32 id)
+{
+ rcu_read_lock();
+ id = snapshot_t(c, id)->tree;
+ rcu_read_unlock();
+
+ return id;
+}
+
+static inline u32 __bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
+{
+ return snapshot_t(c, id)->parent;
+}
+
+static inline u32 bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
+{
+ rcu_read_lock();
+ id = __bch2_snapshot_parent_early(c, id);
+ rcu_read_unlock();
+
+ return id;
+}
+
+static inline u32 __bch2_snapshot_parent(struct bch_fs *c, u32 id)
+{
+#ifdef CONFIG_BCACHEFS_DEBUG
+ u32 parent = snapshot_t(c, id)->parent;
+
+ if (parent &&
+ snapshot_t(c, id)->depth != snapshot_t(c, parent)->depth + 1)
+ panic("id %u depth=%u parent %u depth=%u\n",
+ id, snapshot_t(c, id)->depth,
+ parent, snapshot_t(c, parent)->depth);
+
+ return parent;
+#else
+ return snapshot_t(c, id)->parent;
+#endif
+}
+
+static inline u32 bch2_snapshot_parent(struct bch_fs *c, u32 id)
+{
+ rcu_read_lock();
+ id = __bch2_snapshot_parent(c, id);
+ rcu_read_unlock();
+
+ return id;
+}
+
+static inline u32 bch2_snapshot_nth_parent(struct bch_fs *c, u32 id, u32 n)
+{
+ rcu_read_lock();
+ while (n--)
+ id = __bch2_snapshot_parent(c, id);
+ rcu_read_unlock();
+
+ return id;
+}
+
+u32 bch2_snapshot_skiplist_get(struct bch_fs *, u32);
+
+static inline u32 bch2_snapshot_root(struct bch_fs *c, u32 id)
+{
+ u32 parent;
+
+ rcu_read_lock();
+ while ((parent = __bch2_snapshot_parent(c, id)))
+ id = parent;
+ rcu_read_unlock();
+
+ return id;
+}
+
+static inline u32 __bch2_snapshot_equiv(struct bch_fs *c, u32 id)
+{
+ return snapshot_t(c, id)->equiv;
+}
+
+static inline u32 bch2_snapshot_equiv(struct bch_fs *c, u32 id)
+{
+ rcu_read_lock();
+ id = __bch2_snapshot_equiv(c, id);
+ rcu_read_unlock();
+
+ return id;
+}
+
+static inline bool bch2_snapshot_is_equiv(struct bch_fs *c, u32 id)
+{
+ return id == bch2_snapshot_equiv(c, id);
+}
+
+static inline bool bch2_snapshot_is_internal_node(struct bch_fs *c, u32 id)
+{
+ const struct snapshot_t *s;
+ bool ret;
+
+ rcu_read_lock();
+ s = snapshot_t(c, id);
+ ret = s->children[0];
+ rcu_read_unlock();
+
+ return ret;
+}
+
+static inline u32 bch2_snapshot_is_leaf(struct bch_fs *c, u32 id)
+{
+ return !bch2_snapshot_is_internal_node(c, id);
+}
+
+static inline u32 bch2_snapshot_sibling(struct bch_fs *c, u32 id)
+{
+ const struct snapshot_t *s;
+ u32 parent = __bch2_snapshot_parent(c, id);
+
+ if (!parent)
+ return 0;
+
+ s = snapshot_t(c, __bch2_snapshot_parent(c, id));
+ if (id == s->children[0])
+ return s->children[1];
+ if (id == s->children[1])
+ return s->children[0];
+ return 0;
+}
+
+static inline u32 bch2_snapshot_depth(struct bch_fs *c, u32 parent)
+{
+ u32 depth;
+
+ rcu_read_lock();
+ depth = parent ? snapshot_t(c, parent)->depth + 1 : 0;
+ rcu_read_unlock();
+
+ return depth;
+}
+
+bool __bch2_snapshot_is_ancestor(struct bch_fs *, u32, u32);
+
+static inline bool bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor)
+{
+ return id == ancestor
+ ? true
+ : __bch2_snapshot_is_ancestor(c, id, ancestor);
+}
+
+static inline bool bch2_snapshot_has_children(struct bch_fs *c, u32 id)
+{
+ const struct snapshot_t *t;
+ bool ret;
+
+ rcu_read_lock();
+ t = snapshot_t(c, id);
+ ret = (t->children[0]|t->children[1]) != 0;
+ rcu_read_unlock();
+
+ return ret;
+}
+
+static inline bool snapshot_list_has_id(snapshot_id_list *s, u32 id)
+{
+ u32 *i;
+
+ darray_for_each(*s, i)
+ if (*i == id)
+ return true;
+ return false;
+}
+
+static inline bool snapshot_list_has_ancestor(struct bch_fs *c, snapshot_id_list *s, u32 id)
+{
+ u32 *i;
+
+ darray_for_each(*s, i)
+ if (bch2_snapshot_is_ancestor(c, id, *i))
+ return true;
+ return false;
+}
+
+static inline int snapshot_list_add(struct bch_fs *c, snapshot_id_list *s, u32 id)
+{
+ int ret;
+
+ BUG_ON(snapshot_list_has_id(s, id));
+ ret = darray_push(s, id);
+ if (ret)
+ bch_err(c, "error reallocating snapshot_id_list (size %zu)", s->size);
+ return ret;
+}
+
+int bch2_snapshot_lookup(struct btree_trans *trans, u32 id,
+ struct bch_snapshot *s);
+int bch2_snapshot_get_subvol(struct btree_trans *, u32,
+ struct bch_subvolume *);
+int bch2_snapshot_live(struct btree_trans *trans, u32 id);
+int bch2_snapshot_set_equiv(struct btree_trans *trans, struct bkey_s_c k);
+
+/* only exported for tests: */
+int bch2_snapshot_node_create(struct btree_trans *, u32,
+ u32 *, u32 *, unsigned);
+
+int bch2_check_snapshot_trees(struct bch_fs *);
+int bch2_check_snapshots(struct bch_fs *);
+
+int bch2_snapshot_node_set_deleted(struct btree_trans *, u32);
+int bch2_delete_dead_snapshots_hook(struct btree_trans *,
+ struct btree_trans_commit_hook *);
+void bch2_delete_dead_snapshots_work(struct work_struct *);
+
+int bch2_snapshots_read(struct bch_fs *);
+void bch2_fs_snapshots_exit(struct bch_fs *);
+
+#endif /* _BCACHEFS_SNAPSHOT_H */
#include "errcode.h"
#include "error.h"
#include "fs.h"
+#include "snapshot.h"
#include "subvolume.h"
#include <linux/random.h>
static int bch2_subvolume_delete(struct btree_trans *, u32);
-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->curr_recovery_pass <= 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);
-
- ret = id && id < ancestor
- ? test_bit(ancestor - id - 1, __snapshot_t(t, id)->is_ancestor)
- : id == ancestor;
- rcu_read_unlock();
-
- return ret;
-}
-
-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 bch2_snapshot_depth(struct bch_fs *c, u32 parent)
-{
- u32 depth;
-
- rcu_read_lock();
- depth = parent ? snapshot_t(c, parent)->depth + 1 : 0;
- rcu_read_unlock();
-
- return depth;
-}
-
-struct snapshot_t_free_rcu {
- struct rcu_head rcu;
- struct snapshot_table *t;
-};
-
-static void snapshot_t_free_rcu(struct rcu_head *rcu)
-{
- struct snapshot_t_free_rcu *free_rcu =
- container_of(rcu, struct snapshot_t_free_rcu, rcu);
-
- kvfree(free_rcu->t);
- kfree(free_rcu);
-}
-
-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;
- if (old) {
- struct snapshot_t_free_rcu *rcu =
- kmalloc(sizeof(*rcu), GFP_KERNEL|__GFP_NOFAIL);
-
- rcu->t = old;
- call_rcu(&rcu->rcu, snapshot_t_free_rcu);
- }
-
- 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);
-}
-
-/* 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(const struct bch_fs *c, struct bkey_s_c k,
- enum bkey_invalid_flags flags,
- struct printbuf *err)
-{
- if (bkey_gt(k.k->p, POS(0, U32_MAX)) ||
- bkey_lt(k.k->p, POS(0, 1))) {
- prt_printf(err, "bad pos");
- return -BCH_ERR_invalid_bkey;
- }
-
- return 0;
-}
-
-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;
-}
-
-static struct bkey_i_snapshot_tree *
-__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 snapshot_tree_create(struct btree_trans *trans,
- u32 root_id, u32 subvol_id, u32 *tree_id)
-{
- struct bkey_i_snapshot_tree *n_tree =
- __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: */
-
-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(const 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;
-
- if (bkey_gt(k.k->p, POS(0, U32_MAX)) ||
- bkey_lt(k.k->p, POS(0, 1))) {
- prt_printf(err, "bad pos");
- return -BCH_ERR_invalid_bkey;
- }
-
- s = bkey_s_c_to_snapshot(k);
-
- id = le32_to_cpu(s.v->parent);
- if (id && id <= k.k->p.offset) {
- prt_printf(err, "bad parent node (%u <= %llu)",
- id, k.k->p.offset);
- return -BCH_ERR_invalid_bkey;
- }
-
- if (le32_to_cpu(s.v->children[0]) < le32_to_cpu(s.v->children[1])) {
- prt_printf(err, "children not normalized");
- return -BCH_ERR_invalid_bkey;
- }
-
- if (s.v->children[0] &&
- s.v->children[0] == s.v->children[1]) {
- prt_printf(err, "duplicate child nodes");
- return -BCH_ERR_invalid_bkey;
- }
-
- for (i = 0; i < 2; i++) {
- id = le32_to_cpu(s.v->children[i]);
-
- if (id >= k.k->p.offset) {
- prt_printf(err, "bad child node (%u >= %llu)",
- id, k.k->p.offset);
- return -BCH_ERR_invalid_bkey;
- }
- }
-
- if (bkey_val_bytes(k.k) > offsetof(struct bch_snapshot, skip)) {
- if (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])) {
- prt_printf(err, "skiplist not normalized");
- return -BCH_ERR_invalid_bkey;
- }
-
- for (i = 0; i < ARRAY_SIZE(s.v->skip); i++) {
- id = le32_to_cpu(s.v->skip[i]);
-
- if (!id != !s.v->parent ||
- (s.v->parent &&
- id <= k.k->p.offset)) {
- prt_printf(err, "bad skiplist node %u)", id);
- return -BCH_ERR_invalid_bkey;
- }
- }
- }
-
- return 0;
-}
-
-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);
- u32 parent = id;
-
- 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;
- }
-
- while ((parent = bch2_snapshot_parent_early(c, parent)) &&
- parent - id - 1 < IS_ANCESTOR_BITMAP)
- __set_bit(parent - id - 1, t->is_ancestor);
-
- if (BCH_SNAPSHOT_DELETED(s.v)) {
- set_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags);
- c->recovery_passes_explicit |= BIT_ULL(BCH_RECOVERY_PASS_delete_dead_snapshots);
- }
- } else {
- memset(t, 0, sizeof(*t));
- }
-err:
- mutex_unlock(&c->snapshot_table_lock);
- return ret;
-}
-
-static int 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 snapshot_live(struct btree_trans *trans, u32 id)
-{
- struct bch_snapshot v;
- int ret;
-
- if (!id)
- return 0;
-
- ret = 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);
-}
-
-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 = 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;
- struct bkey_s_c_subvolume s;
- 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;
-
- 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 *s;
-
- *subvol_id = bch2_snapshot_tree_oldest_subvol(c, snapshot_root);
-
- s = bch2_bkey_get_mut_typed(trans, &iter,
- BTREE_ID_subvolumes, POS(0, *subvol_id),
- 0, subvolume);
- ret = PTR_ERR_OR_ZERO(s);
- if (ret)
- return ret;
-
- SET_BCH_SUBVOLUME_SNAP(&s->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 = 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 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 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 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 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)
-{
- struct btree_iter iter;
- struct bkey_s_c k;
- int ret;
-
- ret = bch2_trans_run(c,
- for_each_btree_key_commit(&trans, iter,
- BTREE_ID_snapshot_trees, POS_MIN,
- BTREE_ITER_PREFETCH, k,
- NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
- check_snapshot_tree(&trans, &iter, k)));
-
- if (ret)
- bch_err(c, "error %i checking snapshot trees", 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));
-}
-
-static u32 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, struct bch_snapshot s)
-{
- struct bch_snapshot a;
- unsigned i;
- int ret;
-
- for (i = 0; i < 3; i++) {
- if (!s.parent != !s.skip[i])
- return false;
-
- if (!s.parent)
- continue;
-
- ret = snapshot_lookup(trans, le32_to_cpu(s.skip[i]), &a);
- if (bch2_err_matches(ret, ENOENT))
- return false;
- if (ret)
- return ret;
-
- if (a.tree != s.tree)
- 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) ?:
- 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 cmp_le32(__le32 l, __le32 r)
-{
- return cmp_int(le32_to_cpu(l), le32_to_cpu(r));
-}
-
-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 = 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 = 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 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 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 (le32_to_cpu(s.depth) != real_depth &&
- (c->sb.version_upgrade_complete < bcachefs_metadata_version_snapshot_skiplists ||
- fsck_err(c, "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, s);
- if (ret < 0)
- goto err;
-
- if (!ret &&
- (c->sb.version_upgrade_complete < bcachefs_metadata_version_snapshot_skiplists ||
- fsck_err(c, "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(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)
-{
- struct btree_iter iter;
- struct bkey_s_c k;
- int ret;
-
- /*
- * We iterate backwards as checking/fixing the depth field requires that
- * the parent's depth already be correct:
- */
- ret = bch2_trans_run(c,
- for_each_btree_key_reverse_commit(&trans, iter,
- BTREE_ID_snapshots, POS_MAX,
- BTREE_ITER_PREFETCH, k,
- NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
- check_snapshot(&trans, &iter, k)));
- if (ret)
- bch_err_fn(c, ret);
- return ret;
-}
-
static int check_subvol(struct btree_trans *trans,
struct btree_iter *iter,
struct bkey_s_c k)
subvol = bkey_s_c_to_subvolume(k);
snapid = le32_to_cpu(subvol.v->snapshot);
- ret = snapshot_lookup(trans, snapid, &snapshot);
+ ret = bch2_snapshot_lookup(trans, snapid, &snapshot);
if (bch2_err_matches(ret, ENOENT))
bch_err(c, "subvolume %llu points to nonexistent snapshot %u",
return ret;
}
-void bch2_fs_snapshots_exit(struct bch_fs *c)
-{
- kfree(rcu_dereference_protected(c->snapshots, true));
-}
-
-int bch2_snapshots_read(struct bch_fs *c)
-{
- struct btree_iter iter;
- struct bkey_s_c k;
- int ret = 0;
-
- ret = bch2_trans_run(c,
- for_each_btree_key2(&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)));
- if (ret)
- bch_err_fn(c, ret);
- return ret;
-}
-
-/*
- * Mark a snapshot as deleted, for future cleanup:
- */
-static 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 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 tree_iter = (struct btree_iter) { NULL };
- struct bkey_s_c_snapshot s;
- u32 parent_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(!BCH_SNAPSHOT_DELETED(s.v));
- parent_id = le32_to_cpu(s.v->parent);
-
- 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);
- if (unlikely(ret)) {
- bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
- "missing snapshot %u", parent_id);
- goto err;
- }
-
- for (i = 0; i < 2; i++)
- if (le32_to_cpu(parent->v.children[i]) == id)
- break;
-
- if (i == 2)
- bch_err(c, "snapshot %u missing child pointer to %u",
- parent_id, id);
- else
- parent->v.children[i] = 0;
-
- if (le32_to_cpu(parent->v.children[0]) <
- le32_to_cpu(parent->v.children[1]))
- swap(parent->v.children[0],
- parent->v.children[1]);
- } else {
- /*
- * 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, &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(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;
- }
-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 = __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);
-
-}
-
-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 bch2_delete_redundant_snapshot(struct btree_trans *trans, struct btree_iter *iter,
- 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 = snapshot_live(trans, children[0]) ?:
- snapshot_live(trans, children[1]);
- if (ret < 0)
- return ret;
-
- if (!ret)
- return bch2_snapshot_node_set_deleted(trans, k.k->p.offset);
- return 0;
-}
-
-int bch2_delete_dead_snapshots(struct bch_fs *c)
-{
- struct btree_trans trans;
- struct btree_iter iter;
- struct bkey_s_c k;
- struct bkey_s_c_snapshot snap;
- snapshot_id_list deleted = { 0 };
- u32 i, id;
- int ret = 0;
-
- if (!test_bit(BCH_FS_STARTED, &c->flags)) {
- ret = bch2_fs_read_write_early(c);
- if (ret) {
- bch_err(c, "error deleleting dead snapshots: error going rw: %s", bch2_err_str(ret));
- return ret;
- }
- }
-
- bch2_trans_init(&trans, c, 0, 0);
-
- /*
- * 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, &iter, k));
- if (ret) {
- bch_err(c, "error deleting redundant snapshots: %s", bch2_err_str(ret));
- goto err;
- }
-
- for_each_btree_key2(&trans, iter, BTREE_ID_snapshots,
- POS_MIN, 0, k,
- bch2_snapshot_set_equiv(&trans, k));
- if (ret) {
- bch_err(c, "error in bch2_snapshots_set_equiv: %s", bch2_err_str(ret));
- goto err;
- }
-
- for_each_btree_key(&trans, iter, BTREE_ID_snapshots,
- POS_MIN, 0, k, ret) {
- if (k.k->type != KEY_TYPE_snapshot)
- continue;
-
- snap = bkey_s_c_to_snapshot(k);
- if (BCH_SNAPSHOT_DELETED(snap.v)) {
- ret = snapshot_list_add(c, &deleted, k.k->p.offset);
- if (ret)
- break;
- }
- }
- bch2_trans_iter_exit(&trans, &iter);
-
- if (ret) {
- bch_err(c, "error walking snapshots: %s", bch2_err_str(ret));
- goto err;
- }
-
- for (id = 0; id < BTREE_ID_NR; id++) {
- struct bpos last_pos = POS_MIN;
- snapshot_id_list equiv_seen = { 0 };
-
- if (!btree_type_has_snapshots(id))
- continue;
-
- ret = for_each_btree_key_commit(&trans, iter,
- id, POS_MIN,
- BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS, k,
- NULL, NULL, BTREE_INSERT_NOFAIL,
- snapshot_delete_key(&trans, &iter, k, &deleted, &equiv_seen, &last_pos));
-
- darray_exit(&equiv_seen);
-
- if (ret) {
- bch_err(c, "error deleting snapshot keys: %s", bch2_err_str(ret));
- goto err;
- }
- }
-
- for (i = 0; i < deleted.nr; i++) {
- ret = commit_do(&trans, NULL, NULL, 0,
- bch2_snapshot_node_delete(&trans, deleted.data[i]));
- if (ret) {
- bch_err(c, "error deleting snapshot %u: %s",
- deleted.data[i], bch2_err_str(ret));
- goto err;
- }
- }
-
- clear_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags);
-err:
- darray_exit(&deleted);
- bch2_trans_exit(&trans);
- if (ret)
- bch_err_fn(c, ret);
- return ret;
-}
-
-static void bch2_delete_dead_snapshots_work(struct work_struct *work)
-{
- struct bch_fs *c = container_of(work, struct bch_fs, snapshot_delete_work);
-
- if (test_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags))
- 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);
-}
-
-static int bch2_delete_dead_snapshots_hook(struct btree_trans *trans,
- struct btree_trans_commit_hook *h)
-{
- struct bch_fs *c = trans->c;
-
- set_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags);
-
- if (c->curr_recovery_pass <= BCH_RECOVERY_PASS_delete_dead_snapshots)
- return 0;
-
- bch2_delete_dead_snapshots_async(c);
- return 0;
-}
-
/* Subvolumes: */
int bch2_subvolume_invalid(const struct bch_fs *c, struct bkey_s_c k,
{
struct bch_snapshot snap;
- return snapshot_lookup(trans, snapshot, &snap) ?:
+ return bch2_snapshot_lookup(trans, snapshot, &snap) ?:
bch2_subvolume_get(trans, le32_to_cpu(snap.subvol), true, 0, subvol);
}
-int bch2_subvolume_get_snapshot(struct btree_trans *trans, u32 subvol,
+int bch2_subvolume_get_snapshot(struct btree_trans *trans, u32 subvolid,
u32 *snapid)
{
struct btree_iter iter;
- struct bkey_s_c k;
+ struct bkey_s_c_subvolume subvol;
int ret;
- k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_subvolumes, POS(0, subvol),
- BTREE_ITER_CACHED|
- BTREE_ITER_WITH_UPDATES);
- ret = bkey_err(k) ?: k.k->type == KEY_TYPE_subvolume ? 0 : -BCH_ERR_ENOENT_subvolume;
+ subvol = bch2_bkey_get_iter_typed(trans, &iter,
+ BTREE_ID_subvolumes, POS(0, subvolid),
+ BTREE_ITER_CACHED|BTREE_ITER_WITH_UPDATES,
+ subvolume);
+ ret = bkey_err(subvol);
+ bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
+ "missing subvolume %u", subvolid);
if (likely(!ret))
- *snapid = le32_to_cpu(bkey_s_c_to_subvolume(k).v->snapshot);
- else if (bch2_err_matches(ret, ENOENT))
- bch2_fs_inconsistent(trans->c, "missing subvolume %u", subvol);
+ *snapid = le32_to_cpu(subvol.v->snapshot);
bch2_trans_iter_exit(trans, &iter);
return ret;
}
}
/*
- * Scan for subvolumes with parent @subvolid_to_delete, reparent:
+ * Separate from the snapshot tree in the snapshots btree, we record the tree
+ * structure of how snapshot subvolumes were created - the parent subvolume of
+ * each snapshot subvolume.
+ *
+ * When a subvolume is deleted, we scan for child subvolumes and reparant them,
+ * to avoid dangling references:
*/
static int bch2_subvolumes_reparent(struct btree_trans *trans, u32 subvolid_to_delete)
{
enum bkey_invalid_flags;
-void bch2_snapshot_tree_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
-int bch2_snapshot_tree_invalid(const struct bch_fs *, struct bkey_s_c,
- enum bkey_invalid_flags, struct printbuf *);
-
-#define bch2_bkey_ops_snapshot_tree ((struct bkey_ops) { \
- .key_invalid = bch2_snapshot_tree_invalid, \
- .val_to_text = bch2_snapshot_tree_to_text, \
- .min_val_size = 8, \
-})
-
-int bch2_snapshot_tree_lookup(struct btree_trans *, u32, struct bch_snapshot_tree *);
-
-void bch2_snapshot_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
-int bch2_snapshot_invalid(const struct bch_fs *, struct bkey_s_c,
- enum bkey_invalid_flags, struct printbuf *);
-int bch2_mark_snapshot(struct btree_trans *, enum btree_id, unsigned,
- struct bkey_s_c, struct bkey_s_c, unsigned);
-
-#define bch2_bkey_ops_snapshot ((struct bkey_ops) { \
- .key_invalid = bch2_snapshot_invalid, \
- .val_to_text = bch2_snapshot_to_text, \
- .atomic_trigger = bch2_mark_snapshot, \
- .min_val_size = 24, \
-})
-
-static inline struct snapshot_t *__snapshot_t(struct snapshot_table *t, u32 id)
-{
- return &t->s[U32_MAX - id];
-}
-
-static inline const struct snapshot_t *snapshot_t(struct bch_fs *c, u32 id)
-{
- return __snapshot_t(rcu_dereference(c->snapshots), id);
-}
-
-static inline u32 bch2_snapshot_tree(struct bch_fs *c, u32 id)
-{
- rcu_read_lock();
- id = snapshot_t(c, id)->tree;
- rcu_read_unlock();
-
- return id;
-}
-
-static inline u32 __bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
-{
- return snapshot_t(c, id)->parent;
-}
-
-static inline u32 bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
-{
- rcu_read_lock();
- id = __bch2_snapshot_parent_early(c, id);
- rcu_read_unlock();
-
- return id;
-}
-
-static inline u32 __bch2_snapshot_parent(struct bch_fs *c, u32 id)
-{
-#ifdef CONFIG_BCACHEFS_DEBUG
- u32 parent = snapshot_t(c, id)->parent;
-
- if (parent &&
- snapshot_t(c, id)->depth != snapshot_t(c, parent)->depth + 1)
- panic("id %u depth=%u parent %u depth=%u\n",
- id, snapshot_t(c, id)->depth,
- parent, snapshot_t(c, parent)->depth);
-
- return parent;
-#else
- return snapshot_t(c, id)->parent;
-#endif
-}
-
-static inline u32 bch2_snapshot_parent(struct bch_fs *c, u32 id)
-{
- rcu_read_lock();
- id = __bch2_snapshot_parent(c, id);
- rcu_read_unlock();
-
- return id;
-}
-
-static inline u32 bch2_snapshot_nth_parent(struct bch_fs *c, u32 id, u32 n)
-{
- rcu_read_lock();
- while (n--)
- id = __bch2_snapshot_parent(c, id);
- rcu_read_unlock();
-
- return id;
-}
-
-static inline u32 bch2_snapshot_root(struct bch_fs *c, u32 id)
-{
- u32 parent;
-
- rcu_read_lock();
- while ((parent = __bch2_snapshot_parent(c, id)))
- id = parent;
- rcu_read_unlock();
-
- return id;
-}
-
-static inline u32 __bch2_snapshot_equiv(struct bch_fs *c, u32 id)
-{
- return snapshot_t(c, id)->equiv;
-}
-
-static inline u32 bch2_snapshot_equiv(struct bch_fs *c, u32 id)
-{
- rcu_read_lock();
- id = __bch2_snapshot_equiv(c, id);
- rcu_read_unlock();
-
- return id;
-}
-
-static inline bool bch2_snapshot_is_equiv(struct bch_fs *c, u32 id)
-{
- return id == bch2_snapshot_equiv(c, id);
-}
-
-static inline bool bch2_snapshot_is_internal_node(struct bch_fs *c, u32 id)
-{
- const struct snapshot_t *s;
- bool ret;
-
- rcu_read_lock();
- s = snapshot_t(c, id);
- ret = s->children[0];
- rcu_read_unlock();
-
- return ret;
-}
-
-static inline u32 bch2_snapshot_is_leaf(struct bch_fs *c, u32 id)
-{
- return !bch2_snapshot_is_internal_node(c, id);
-}
-
-static inline u32 bch2_snapshot_sibling(struct bch_fs *c, u32 id)
-{
- const struct snapshot_t *s;
- u32 parent = __bch2_snapshot_parent(c, id);
-
- if (!parent)
- return 0;
-
- s = snapshot_t(c, __bch2_snapshot_parent(c, id));
- if (id == s->children[0])
- return s->children[1];
- if (id == s->children[1])
- return s->children[0];
- return 0;
-}
-
-bool __bch2_snapshot_is_ancestor(struct bch_fs *, u32, u32);
-
-static inline bool bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor)
-{
- return id == ancestor
- ? true
- : __bch2_snapshot_is_ancestor(c, id, ancestor);
-}
-
-static inline bool bch2_snapshot_has_children(struct bch_fs *c, u32 id)
-{
- const struct snapshot_t *t;
- bool ret;
-
- rcu_read_lock();
- t = snapshot_t(c, id);
- ret = (t->children[0]|t->children[1]) != 0;
- rcu_read_unlock();
-
- return ret;
-}
-
-static inline bool snapshot_list_has_id(snapshot_id_list *s, u32 id)
-{
- u32 *i;
-
- darray_for_each(*s, i)
- if (*i == id)
- return true;
- return false;
-}
-
-static inline bool snapshot_list_has_ancestor(struct bch_fs *c, snapshot_id_list *s, u32 id)
-{
- u32 *i;
-
- darray_for_each(*s, i)
- if (bch2_snapshot_is_ancestor(c, id, *i))
- return true;
- return false;
-}
-
-static inline int snapshot_list_add(struct bch_fs *c, snapshot_id_list *s, u32 id)
-{
- int ret;
-
- BUG_ON(snapshot_list_has_id(s, id));
- ret = darray_push(s, id);
- if (ret)
- bch_err(c, "error reallocating snapshot_id_list (size %zu)", s->size);
- return ret;
-}
-
-int bch2_check_snapshot_trees(struct bch_fs *);
-int bch2_check_snapshots(struct bch_fs *);
int bch2_check_subvols(struct bch_fs *);
-void bch2_fs_snapshots_exit(struct bch_fs *);
-int bch2_snapshots_read(struct bch_fs *);
-
int bch2_subvolume_invalid(const struct bch_fs *, struct bkey_s_c,
unsigned, struct printbuf *);
void bch2_subvolume_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
int bch2_subvolume_get(struct btree_trans *, unsigned,
bool, int, struct bch_subvolume *);
-int bch2_snapshot_get_subvol(struct btree_trans *, u32,
- struct bch_subvolume *);
int bch2_subvolume_get_snapshot(struct btree_trans *, u32, u32 *);
-/* only exported for tests: */
-int bch2_snapshot_node_create(struct btree_trans *, u32,
- u32 *, u32 *, unsigned);
-
int bch2_delete_dead_snapshots(struct bch_fs *);
void bch2_delete_dead_snapshots_async(struct bch_fs *);
#include "recovery.h"
#include "replicas.h"
#include "sb-clean.h"
+#include "snapshot.h"
#include "subvolume.h"
#include "super.h"
#include "super-io.h"
#include "bcachefs.h"
#include "btree_update.h"
#include "journal_reclaim.h"
-#include "subvolume.h"
+#include "snapshot.h"
#include "tests.h"
#include "linux/kthread.h"
return cmp_int(l, r);
}
+static inline int cmp_le32(__le32 l, __le32 r)
+{
+ return cmp_int(le32_to_cpu(l), le32_to_cpu(r));
+}
+
#include <linux/uuid.h>
#endif /* _BCACHEFS_UTIL_H */
projects / linux-2.6-microblaze.git / commitdiff