--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#include "bcachefs.h"
+#include "btree_key_cache.h"
+#include "btree_update.h"
+#include "error.h"
+#include "subvolume.h"
+
+/* Snapshot tree: */
+
+static void bch2_delete_dead_snapshots_work(struct work_struct *);
+static void bch2_delete_dead_snapshots(struct bch_fs *);
+
+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);
+
+ pr_buf(out, "is_subvol %llu deleted %llu parent %u children %u %u subvol %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));
+}
+
+const char *bch2_snapshot_invalid(const struct bch_fs *c, struct bkey_s_c k)
+{
+ struct bkey_s_c_snapshot s;
+ u32 i, id;
+
+ if (bkey_cmp(k.k->p, POS(0, U32_MAX)) > 0 ||
+ bkey_cmp(k.k->p, POS(0, 1)) < 0)
+ return "bad pos";
+
+ if (bkey_val_bytes(k.k) != sizeof(struct bch_snapshot))
+ return "bad val size";
+
+ s = bkey_s_c_to_snapshot(k);
+
+ id = le32_to_cpu(s.v->parent);
+ if (id && id <= k.k->p.offset)
+ return "bad parent node";
+
+ if (le32_to_cpu(s.v->children[0]) < le32_to_cpu(s.v->children[1]))
+ return "children not normalized";
+
+ if (s.v->children[0] &&
+ s.v->children[0] == s.v->children[1])
+ return "duplicate child nodes";
+
+ for (i = 0; i < 2; i++) {
+ id = le32_to_cpu(s.v->children[i]);
+
+ if (id >= k.k->p.offset)
+ return "bad child node";
+ }
+
+ return NULL;
+}
+
+int bch2_mark_snapshot(struct bch_fs *c,
+ struct bkey_s_c old, struct bkey_s_c new,
+ u64 journal_seq, unsigned flags)
+{
+ struct snapshot_t *t;
+
+ t = genradix_ptr_alloc(&c->snapshots,
+ U32_MAX - new.k->p.offset,
+ GFP_KERNEL);
+ if (!t)
+ return -ENOMEM;
+
+ 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;
+ } else {
+ t->parent = 0;
+ t->children[0] = 0;
+ t->children[1] = 0;
+ t->subvol = 0;
+ }
+
+ return 0;
+}
+
+static int subvol_lookup(struct btree_trans *trans, unsigned id, struct bch_subvolume *s)
+{
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ int ret;
+
+ bch2_trans_iter_init(trans, &iter, BTREE_ID_subvolumes, POS(0, id), 0);
+ k = bch2_btree_iter_peek_slot(&iter);
+ ret = bkey_err(k) ?: k.k->type == KEY_TYPE_subvolume ? 0 : -ENOENT;
+
+ if (!ret)
+ *s = *bkey_s_c_to_subvolume(k).v;
+
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+static int snapshot_lookup(struct btree_trans *trans, u32 id,
+ struct bch_snapshot *s)
+{
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ int ret;
+
+ bch2_trans_iter_init(trans, &iter, BTREE_ID_snapshots, POS(0, id),
+ BTREE_ITER_WITH_UPDATES);
+ k = bch2_btree_iter_peek_slot(&iter);
+ ret = bkey_err(k) ?: k.k->type == KEY_TYPE_snapshot ? 0 : -ENOENT;
+
+ if (!ret)
+ *s = *bkey_s_c_to_snapshot(k).v;
+
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+static int snapshot_live(struct btree_trans *trans, u32 id)
+{
+ struct bch_snapshot v;
+ int ret;
+
+ if (!id)
+ return 0;
+
+ ret = lockrestart_do(trans, snapshot_lookup(trans, id, &v));
+ if (ret == -ENOENT)
+ bch_err(trans->c, "snapshot node %u not found", id);
+ if (ret)
+ return ret;
+
+ return !BCH_SNAPSHOT_DELETED(&v);
+}
+
+static int bch2_snapshots_set_equiv(struct btree_trans *trans)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ struct bkey_s_c_snapshot snap;
+ unsigned i;
+ int ret;
+
+ for_each_btree_key(trans, iter, BTREE_ID_snapshots,
+ POS_MIN, 0, k, ret) {
+ u32 id = k.k->p.offset, child[2];
+ unsigned nr_live = 0, live_idx;
+
+ if (k.k->type != KEY_TYPE_snapshot)
+ continue;
+
+ 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++) {
+ ret = snapshot_live(trans, child[i]);
+ if (ret < 0)
+ break;
+
+ if (ret)
+ live_idx = i;
+ nr_live += ret;
+ }
+
+ snapshot_t(c, id)->equiv = nr_live == 1
+ ? snapshot_t(c, child[live_idx])->equiv
+ : id;
+ }
+ bch2_trans_iter_exit(trans, &iter);
+
+ if (ret)
+ bch_err(c, "error walking snapshots: %i", ret);
+
+ return ret;
+}
+
+/* fsck: */
+static int bch2_snapshot_check(struct btree_trans *trans,
+ struct bkey_s_c_snapshot s)
+{
+ struct bch_subvolume subvol;
+ struct bch_snapshot v;
+ u32 i, id;
+ int ret;
+
+ id = le32_to_cpu(s.v->subvol);
+ ret = lockrestart_do(trans, subvol_lookup(trans, id, &subvol));
+ if (ret == -ENOENT)
+ bch_err(trans->c, "snapshot node %llu has nonexistent subvolume %u",
+ s.k->p.offset, id);
+ if (ret)
+ return ret;
+
+ if (BCH_SNAPSHOT_SUBVOL(s.v) != (le32_to_cpu(subvol.snapshot) == s.k->p.offset)) {
+ bch_err(trans->c, "snapshot node %llu has wrong BCH_SNAPSHOT_SUBVOL",
+ s.k->p.offset);
+ return -EINVAL;
+ }
+
+ id = le32_to_cpu(s.v->parent);
+ if (id) {
+ ret = lockrestart_do(trans, snapshot_lookup(trans, id, &v));
+ if (ret == -ENOENT)
+ bch_err(trans->c, "snapshot node %llu has nonexistent parent %u",
+ s.k->p.offset, id);
+ if (ret)
+ return ret;
+
+ if (le32_to_cpu(v.children[0]) != s.k->p.offset &&
+ le32_to_cpu(v.children[1]) != s.k->p.offset) {
+ bch_err(trans->c, "snapshot parent %u missing pointer to child %llu",
+ id, s.k->p.offset);
+ return -EINVAL;
+ }
+ }
+
+ for (i = 0; i < 2 && s.v->children[i]; i++) {
+ id = le32_to_cpu(s.v->children[i]);
+
+ ret = lockrestart_do(trans, snapshot_lookup(trans, id, &v));
+ if (ret == -ENOENT)
+ bch_err(trans->c, "snapshot node %llu has nonexistent child %u",
+ s.k->p.offset, id);
+ if (ret)
+ return ret;
+
+ if (le32_to_cpu(v.parent) != s.k->p.offset) {
+ bch_err(trans->c, "snapshot child %u has wrong parent (got %u should be %llu)",
+ id, le32_to_cpu(v.parent), s.k->p.offset);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+int bch2_fs_snapshots_check(struct bch_fs *c)
+{
+ struct btree_trans trans;
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ struct bch_snapshot s;
+ unsigned id;
+ int ret;
+
+ bch2_trans_init(&trans, c, 0, 0);
+
+ for_each_btree_key(&trans, iter, BTREE_ID_snapshots,
+ POS_MIN, 0, k, ret) {
+ if (k.k->type != KEY_TYPE_snapshot)
+ continue;
+
+ ret = bch2_snapshot_check(&trans, bkey_s_c_to_snapshot(k));
+ if (ret)
+ break;
+ }
+ bch2_trans_iter_exit(&trans, &iter);
+
+ if (ret) {
+ bch_err(c, "error %i checking snapshots", ret);
+ goto err;
+ }
+
+ for_each_btree_key(&trans, iter, BTREE_ID_subvolumes,
+ POS_MIN, 0, k, ret) {
+ if (k.k->type != KEY_TYPE_subvolume)
+ continue;
+again_2:
+ id = le32_to_cpu(bkey_s_c_to_subvolume(k).v->snapshot);
+ ret = snapshot_lookup(&trans, id, &s);
+
+ if (ret == -EINTR) {
+ k = bch2_btree_iter_peek(&iter);
+ goto again_2;
+ } else if (ret == -ENOENT)
+ bch_err(c, "subvolume %llu points to nonexistent snapshot %u",
+ k.k->p.offset, id);
+ else if (ret)
+ break;
+ }
+ bch2_trans_iter_exit(&trans, &iter);
+err:
+ bch2_trans_exit(&trans);
+ return ret;
+}
+
+void bch2_fs_snapshots_exit(struct bch_fs *c)
+{
+ genradix_free(&c->snapshots);
+}
+
+int bch2_fs_snapshots_start(struct bch_fs *c)
+{
+ struct btree_trans trans;
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ bool have_deleted = false;
+ int ret = 0;
+
+ bch2_trans_init(&trans, c, 0, 0);
+
+ for_each_btree_key(&trans, iter, BTREE_ID_snapshots,
+ POS_MIN, 0, k, ret) {
+ if (bkey_cmp(k.k->p, POS(0, U32_MAX)) > 0)
+ break;
+
+ if (k.k->type != KEY_TYPE_snapshot) {
+ bch_err(c, "found wrong key type %u in snapshot node table",
+ k.k->type);
+ continue;
+ }
+
+ if (BCH_SNAPSHOT_DELETED(bkey_s_c_to_snapshot(k).v))
+ have_deleted = true;
+
+ ret = bch2_mark_snapshot(c, bkey_s_c_null, k, 0, 0);
+ if (ret)
+ break;
+ }
+ bch2_trans_iter_exit(&trans, &iter);
+
+ if (ret)
+ goto err;
+
+ ret = bch2_snapshots_set_equiv(&trans);
+ if (ret)
+ goto err;
+err:
+ bch2_trans_exit(&trans);
+
+ if (!ret && have_deleted) {
+ bch_info(c, "restarting deletion of dead snapshots");
+ if (c->opts.fsck) {
+ bch2_delete_dead_snapshots_work(&c->snapshot_delete_work);
+ } else {
+ bch2_delete_dead_snapshots(c);
+ }
+ }
+
+ 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_s_c k;
+ struct bkey_i_snapshot *s;
+ int ret = 0;
+
+ bch2_trans_iter_init(trans, &iter, BTREE_ID_snapshots, POS(0, id),
+ BTREE_ITER_INTENT);
+ k = bch2_btree_iter_peek_slot(&iter);
+ ret = bkey_err(k);
+ if (ret)
+ goto err;
+
+ if (k.k->type != KEY_TYPE_snapshot) {
+ bch2_fs_inconsistent(trans->c, "missing snapshot %u", id);
+ ret = -ENOENT;
+ goto err;
+ }
+
+ /* already deleted? */
+ if (BCH_SNAPSHOT_DELETED(bkey_s_c_to_snapshot(k).v))
+ goto err;
+
+ s = bch2_trans_kmalloc(trans, sizeof(*s));
+ ret = PTR_ERR_OR_ZERO(s);
+ if (ret)
+ goto err;
+
+ bkey_reassemble(&s->k_i, k);
+
+ SET_BCH_SNAPSHOT_DELETED(&s->v, true);
+ ret = bch2_trans_update(trans, &iter, &s->k_i, 0);
+ if (ret)
+ goto err;
+err:
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+static int bch2_snapshot_node_delete(struct btree_trans *trans, u32 id)
+{
+ struct btree_iter iter, p_iter = (struct btree_iter) { NULL };
+ struct bkey_s_c k;
+ struct bkey_s_c_snapshot s;
+ struct bkey_i_snapshot *parent;
+ u32 parent_id;
+ unsigned i;
+ int ret = 0;
+
+ bch2_trans_iter_init(trans, &iter, BTREE_ID_snapshots, POS(0, id),
+ BTREE_ITER_INTENT);
+ k = bch2_btree_iter_peek_slot(&iter);
+ ret = bkey_err(k);
+ if (ret)
+ goto err;
+
+ if (k.k->type != KEY_TYPE_snapshot) {
+ bch2_fs_inconsistent(trans->c, "missing snapshot %u", id);
+ ret = -ENOENT;
+ goto err;
+ }
+
+ s = bkey_s_c_to_snapshot(k);
+
+ BUG_ON(!BCH_SNAPSHOT_DELETED(s.v));
+ parent_id = le32_to_cpu(s.v->parent);
+
+ if (parent_id) {
+ bch2_trans_iter_init(trans, &p_iter, BTREE_ID_snapshots,
+ POS(0, parent_id),
+ BTREE_ITER_INTENT);
+ k = bch2_btree_iter_peek_slot(&p_iter);
+ ret = bkey_err(k);
+ if (ret)
+ goto err;
+
+ if (k.k->type != KEY_TYPE_snapshot) {
+ bch2_fs_inconsistent(trans->c, "missing snapshot %u", parent_id);
+ ret = -ENOENT;
+ goto err;
+ }
+
+ parent = bch2_trans_kmalloc(trans, sizeof(*parent));
+ ret = PTR_ERR_OR_ZERO(parent);
+ if (ret)
+ goto err;
+
+ bkey_reassemble(&parent->k_i, k);
+
+ for (i = 0; i < 2; i++)
+ if (le32_to_cpu(parent->v.children[i]) == id)
+ break;
+
+ if (i == 2)
+ bch_err(trans->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]);
+
+ ret = bch2_trans_update(trans, &p_iter, &parent->k_i, 0);
+ if (ret)
+ goto err;
+ }
+
+ ret = bch2_btree_delete_at(trans, &iter, 0);
+err:
+ bch2_trans_iter_exit(trans, &p_iter);
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+static int bch2_snapshot_node_create(struct btree_trans *trans, u32 parent,
+ u32 *new_snapids,
+ u32 *snapshot_subvols,
+ unsigned nr_snapids)
+{
+ struct btree_iter iter;
+ struct bkey_i_snapshot *n;
+ struct bkey_s_c k;
+ unsigned i;
+ int ret = 0;
+
+ 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 = -ENOSPC;
+ goto err;
+ }
+
+ n = bch2_trans_kmalloc(trans, sizeof(*n));
+ ret = PTR_ERR_OR_ZERO(n);
+ if (ret)
+ return ret;
+
+ bkey_snapshot_init(&n->k_i);
+ n->k.p = iter.pos;
+ n->v.flags = 0;
+ n->v.parent = cpu_to_le32(parent);
+ n->v.subvol = cpu_to_le32(snapshot_subvols[i]);
+ n->v.pad = 0;
+ SET_BCH_SNAPSHOT_SUBVOL(&n->v, true);
+
+ bch2_trans_update(trans, &iter, &n->k_i, 0);
+
+ ret = bch2_mark_snapshot(trans->c, bkey_s_c_null, bkey_i_to_s_c(&n->k_i), 0, 0);
+ if (ret)
+ break;
+
+ new_snapids[i] = iter.pos.offset;
+ }
+
+ if (parent) {
+ bch2_btree_iter_set_pos(&iter, POS(0, parent));
+ k = bch2_btree_iter_peek(&iter);
+ ret = bkey_err(k);
+ if (ret)
+ goto err;
+
+ if (k.k->type != KEY_TYPE_snapshot) {
+ bch_err(trans->c, "snapshot %u not found", parent);
+ ret = -ENOENT;
+ goto err;
+ }
+
+ n = bch2_trans_kmalloc(trans, sizeof(*n));
+ ret = PTR_ERR_OR_ZERO(n);
+ if (ret)
+ return ret;
+
+ bkey_reassemble(&n->k_i, k);
+
+ if (n->v.children[0] || n->v.children[1]) {
+ bch_err(trans->c, "Trying to add child snapshot nodes to parent that already has children");
+ ret = -EINVAL;
+ goto err;
+ }
+
+ n->v.children[0] = cpu_to_le32(new_snapids[0]);
+ n->v.children[1] = cpu_to_le32(new_snapids[1]);
+ SET_BCH_SNAPSHOT_SUBVOL(&n->v, false);
+ bch2_trans_update(trans, &iter, &n->k_i, 0);
+ }
+err:
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+/* List of snapshot IDs that are being deleted: */
+struct snapshot_id_list {
+ u32 nr;
+ u32 size;
+ u32 *d;
+};
+
+static bool snapshot_list_has_id(struct snapshot_id_list *s, u32 id)
+{
+ unsigned i;
+
+ for (i = 0; i < s->nr; i++)
+ if (id == s->d[i])
+ return true;
+ return false;
+}
+
+static int snapshot_id_add(struct snapshot_id_list *s, u32 id)
+{
+ BUG_ON(snapshot_list_has_id(s, id));
+
+ if (s->nr == s->size) {
+ size_t new_size = max(8U, s->size * 2);
+ void *n = krealloc(s->d,
+ new_size * sizeof(s->d[0]),
+ GFP_KERNEL);
+ if (!n) {
+ pr_err("error allocating snapshot ID list");
+ return -ENOMEM;
+ }
+
+ s->d = n;
+ s->size = new_size;
+ };
+
+ s->d[s->nr++] = id;
+ return 0;
+}
+
+static int bch2_snapshot_delete_keys_btree(struct btree_trans *trans,
+ struct snapshot_id_list *deleted,
+ enum btree_id btree_id)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ struct snapshot_id_list equiv_seen = { 0 };
+ struct bpos last_pos = POS_MIN;
+ int ret = 0;
+
+ /*
+ * XXX: We should also delete whiteouts that no longer overwrite
+ * anything
+ */
+
+ bch2_trans_iter_init(trans, &iter, btree_id, POS_MIN,
+ BTREE_ITER_INTENT|
+ BTREE_ITER_PREFETCH|
+ BTREE_ITER_NOT_EXTENTS|
+ BTREE_ITER_ALL_SNAPSHOTS);
+
+ while ((bch2_trans_begin(trans),
+ (k = bch2_btree_iter_peek(&iter)).k) &&
+ !(ret = bkey_err(k))) {
+ u32 equiv = snapshot_t(c, k.k->p.snapshot)->equiv;
+
+ if (bkey_cmp(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)) {
+ if (btree_id == BTREE_ID_inodes &&
+ bch2_btree_key_cache_flush(trans, btree_id, iter.pos))
+ continue;
+
+ ret = __bch2_trans_do(trans, NULL, NULL,
+ BTREE_INSERT_NOFAIL,
+ bch2_btree_iter_traverse(&iter) ?:
+ bch2_btree_delete_at(trans, &iter,
+ BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE));
+ if (ret)
+ break;
+ } else {
+ ret = snapshot_id_add(&equiv_seen, equiv);
+ if (ret)
+ break;
+ }
+
+ bch2_btree_iter_advance(&iter);
+ }
+ bch2_trans_iter_exit(trans, &iter);
+
+ kfree(equiv_seen.d);
+
+ 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);
+ struct btree_trans trans;
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ struct bkey_s_c_snapshot snap;
+ struct snapshot_id_list deleted = { 0 };
+ u32 i, id, children[2];
+ int ret = 0;
+
+ 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:
+ */
+ 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) ||
+ BCH_SNAPSHOT_SUBVOL(snap.v))
+ continue;
+
+ 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)
+ break;
+ if (ret)
+ continue;
+
+ ret = __bch2_trans_do(&trans, NULL, NULL, 0,
+ bch2_snapshot_node_set_deleted(&trans, iter.pos.offset));
+ if (ret) {
+ bch_err(c, "error deleting snapshot %llu: %i", iter.pos.offset, ret);
+ break;
+ }
+ }
+ bch2_trans_iter_exit(&trans, &iter);
+
+ if (ret) {
+ bch_err(c, "error walking snapshots: %i", ret);
+ goto err;
+ }
+
+ ret = bch2_snapshots_set_equiv(&trans);
+ if (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_id_add(&deleted, k.k->p.offset);
+ if (ret)
+ break;
+ }
+ }
+ bch2_trans_iter_exit(&trans, &iter);
+
+ if (ret) {
+ bch_err(c, "error walking snapshots: %i", ret);
+ goto err;
+ }
+
+ for (id = 0; id < BTREE_ID_NR; id++) {
+ if (!btree_type_has_snapshots(id))
+ continue;
+
+ ret = bch2_snapshot_delete_keys_btree(&trans, &deleted, id);
+ if (ret) {
+ bch_err(c, "error deleting snapshot keys: %i", ret);
+ goto err;
+ }
+ }
+
+ for (i = 0; i < deleted.nr; i++) {
+ ret = __bch2_trans_do(&trans, NULL, NULL, 0,
+ bch2_snapshot_node_delete(&trans, deleted.d[i]));
+ if (ret) {
+ bch_err(c, "error deleting snapshot %u: %i",
+ deleted.d[i], ret);
+ goto err;
+ }
+ }
+err:
+ kfree(deleted.d);
+ bch2_trans_exit(&trans);
+ percpu_ref_put(&c->writes);
+}
+
+static void bch2_delete_dead_snapshots(struct bch_fs *c)
+{
+ if (unlikely(!percpu_ref_tryget(&c->writes)))
+ return;
+
+ if (!queue_work(system_long_wq, &c->snapshot_delete_work))
+ percpu_ref_put(&c->writes);
+}
+
+static int bch2_delete_dead_snapshots_hook(struct btree_trans *trans,
+ struct btree_trans_commit_hook *h)
+{
+ bch2_delete_dead_snapshots(trans->c);
+ return 0;
+}
+
+/* Subvolumes: */
+
+const char *bch2_subvolume_invalid(const struct bch_fs *c, struct bkey_s_c k)
+{
+ if (bkey_cmp(k.k->p, SUBVOL_POS_MIN) < 0)
+ return "invalid pos";
+
+ if (bkey_cmp(k.k->p, SUBVOL_POS_MAX) > 0)
+ return "invalid pos";
+
+ if (bkey_val_bytes(k.k) != sizeof(struct bch_subvolume))
+ return "bad val size";
+
+ return NULL;
+}
+
+void bch2_subvolume_to_text(struct printbuf *out, struct bch_fs *c,
+ struct bkey_s_c k)
+{
+ struct bkey_s_c_subvolume s = bkey_s_c_to_subvolume(k);
+
+ pr_buf(out, "root %llu snapshot id %u",
+ le64_to_cpu(s.v->inode),
+ le32_to_cpu(s.v->snapshot));
+}
+
+int bch2_subvolume_get_snapshot(struct btree_trans *trans, u32 subvol,
+ u32 *snapid)
+{
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ int ret;
+
+ bch2_trans_iter_init(trans, &iter, BTREE_ID_subvolumes,
+ POS(0, subvol),
+ BTREE_ITER_CACHED|
+ BTREE_ITER_WITH_UPDATES);
+ k = bch2_btree_iter_peek_slot(&iter);
+ ret = bkey_err(k);
+ if (ret)
+ goto err;
+
+ if (k.k->type != KEY_TYPE_subvolume) {
+ bch2_fs_inconsistent(trans->c, "missing subvolume %u", subvol);
+ ret = -EIO;
+ goto err;
+ }
+
+ *snapid = le32_to_cpu(bkey_s_c_to_subvolume(k).v->snapshot);
+err:
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+/* XXX: mark snapshot id for deletion, walk btree and delete: */
+int bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid,
+ int deleting_snapshot)
+{
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ struct bkey_s_c_subvolume subvol;
+ struct btree_trans_commit_hook *h;
+ struct bkey_i *delete;
+ u32 snapid;
+ int ret = 0;
+
+ bch2_trans_iter_init(trans, &iter, BTREE_ID_subvolumes,
+ POS(0, subvolid),
+ BTREE_ITER_CACHED|
+ BTREE_ITER_INTENT);
+ k = bch2_btree_iter_peek_slot(&iter);
+ ret = bkey_err(k);
+ if (ret)
+ goto err;
+
+ if (k.k->type != KEY_TYPE_subvolume) {
+ bch2_fs_inconsistent(trans->c, "missing subvolume %u", subvolid);
+ ret = -EIO;
+ goto err;
+ }
+
+ subvol = bkey_s_c_to_subvolume(k);
+ snapid = le32_to_cpu(subvol.v->snapshot);
+
+ if (deleting_snapshot >= 0 &&
+ deleting_snapshot != BCH_SUBVOLUME_SNAP(subvol.v)) {
+ ret = -ENOENT;
+ goto err;
+ }
+
+ delete = bch2_trans_kmalloc(trans, sizeof(*delete));
+ ret = PTR_ERR_OR_ZERO(delete);
+ if (ret)
+ goto err;
+
+ bkey_init(&delete->k);
+ delete->k.p = iter.pos;
+ ret = bch2_trans_update(trans, &iter, delete, 0);
+ if (ret)
+ goto err;
+
+ ret = bch2_snapshot_node_set_deleted(trans, snapid);
+
+ h = bch2_trans_kmalloc(trans, sizeof(*h));
+ ret = PTR_ERR_OR_ZERO(h);
+ if (ret)
+ goto err;
+
+ h->fn = bch2_delete_dead_snapshots_hook;
+ bch2_trans_commit_hook(trans, h);
+err:
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+int bch2_subvolume_create(struct btree_trans *trans, u64 inode,
+ u32 src_subvolid,
+ u32 *new_subvolid,
+ u32 *new_snapshotid,
+ bool ro)
+{
+ struct btree_iter dst_iter, src_iter = (struct btree_iter) { NULL };
+ struct bkey_i_subvolume *new_subvol = NULL;
+ struct bkey_i_subvolume *src_subvol = NULL;
+ struct bkey_s_c k;
+ u32 parent = 0, new_nodes[2], snapshot_subvols[2];
+ int ret = 0;
+
+ for_each_btree_key(trans, dst_iter, BTREE_ID_subvolumes, SUBVOL_POS_MIN,
+ BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) {
+ if (bkey_cmp(k.k->p, SUBVOL_POS_MAX) > 0)
+ break;
+ if (bkey_deleted(k.k))
+ goto found_slot;
+ }
+
+ if (!ret)
+ ret = -ENOSPC;
+ goto err;
+found_slot:
+ snapshot_subvols[0] = dst_iter.pos.offset;
+ snapshot_subvols[1] = src_subvolid;
+
+ if (src_subvolid) {
+ /* Creating a snapshot: */
+ src_subvol = bch2_trans_kmalloc(trans, sizeof(*src_subvol));
+ ret = PTR_ERR_OR_ZERO(src_subvol);
+ if (ret)
+ goto err;
+
+ bch2_trans_iter_init(trans, &src_iter, BTREE_ID_subvolumes,
+ POS(0, src_subvolid),
+ BTREE_ITER_CACHED|
+ BTREE_ITER_INTENT);
+ k = bch2_btree_iter_peek_slot(&src_iter);
+ ret = bkey_err(k);
+ if (ret)
+ goto err;
+
+ if (k.k->type != KEY_TYPE_subvolume) {
+ bch_err(trans->c, "subvolume %u not found", src_subvolid);
+ ret = -ENOENT;
+ goto err;
+ }
+
+ bkey_reassemble(&src_subvol->k_i, k);
+ parent = le32_to_cpu(src_subvol->v.snapshot);
+ }
+
+ ret = bch2_snapshot_node_create(trans, parent, new_nodes,
+ snapshot_subvols,
+ src_subvolid ? 2 : 1);
+ if (ret)
+ goto err;
+
+ if (src_subvolid) {
+ src_subvol->v.snapshot = cpu_to_le32(new_nodes[1]);
+ bch2_trans_update(trans, &src_iter, &src_subvol->k_i, 0);
+ }
+
+ new_subvol = bch2_trans_kmalloc(trans, sizeof(*new_subvol));
+ ret = PTR_ERR_OR_ZERO(new_subvol);
+ if (ret)
+ goto err;
+
+ bkey_subvolume_init(&new_subvol->k_i);
+ new_subvol->v.flags = 0;
+ new_subvol->v.snapshot = cpu_to_le32(new_nodes[0]);
+ new_subvol->v.inode = cpu_to_le64(inode);
+ SET_BCH_SUBVOLUME_RO(&new_subvol->v, ro);
+ SET_BCH_SUBVOLUME_SNAP(&new_subvol->v, src_subvolid != 0);
+ new_subvol->k.p = dst_iter.pos;
+ bch2_trans_update(trans, &dst_iter, &new_subvol->k_i, 0);
+
+ *new_subvolid = new_subvol->k.p.offset;
+ *new_snapshotid = new_nodes[0];
+err:
+ bch2_trans_iter_exit(trans, &src_iter);
+ bch2_trans_iter_exit(trans, &dst_iter);
+ return ret;
+}
+
+int bch2_fs_subvolumes_init(struct bch_fs *c)
+{
+ INIT_WORK(&c->snapshot_delete_work, bch2_delete_dead_snapshots_work);
+ return 0;
+}
projects / linux-block.git / commitdiff