--- /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 "subvolume.h"
+
+#include <linux/random.h>
+
+static int bch2_subvolume_delete(struct btree_trans *, u32);
+
+static int check_subvol(struct btree_trans *trans,
+ struct btree_iter *iter,
+ struct bkey_s_c k)
+{
+ struct bch_fs *c = trans->c;
+ struct bkey_s_c_subvolume subvol;
+ struct bch_snapshot snapshot;
+ unsigned snapid;
+ int ret = 0;
+
+ if (k.k->type != KEY_TYPE_subvolume)
+ return 0;
+
+ subvol = bkey_s_c_to_subvolume(k);
+ snapid = le32_to_cpu(subvol.v->snapshot);
+ ret = bch2_snapshot_lookup(trans, snapid, &snapshot);
+
+ if (bch2_err_matches(ret, ENOENT))
+ bch_err(c, "subvolume %llu points to nonexistent snapshot %u",
+ k.k->p.offset, snapid);
+ if (ret)
+ return ret;
+
+ if (BCH_SUBVOLUME_UNLINKED(subvol.v)) {
+ ret = bch2_subvolume_delete(trans, iter->pos.offset);
+ bch_err_msg(c, ret, "deleting subvolume %llu", iter->pos.offset);
+ return ret ?: -BCH_ERR_transaction_restart_nested;
+ }
+
+ if (!BCH_SUBVOLUME_SNAP(subvol.v)) {
+ u32 snapshot_root = bch2_snapshot_root(c, le32_to_cpu(subvol.v->snapshot));
+ u32 snapshot_tree;
+ struct bch_snapshot_tree st;
+
+ rcu_read_lock();
+ snapshot_tree = snapshot_t(c, snapshot_root)->tree;
+ rcu_read_unlock();
+
+ ret = bch2_snapshot_tree_lookup(trans, snapshot_tree, &st);
+
+ bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
+ "%s: snapshot tree %u not found", __func__, snapshot_tree);
+
+ if (ret)
+ return ret;
+
+ if (fsck_err_on(le32_to_cpu(st.master_subvol) != subvol.k->p.offset,
+ c, subvol_not_master_and_not_snapshot,
+ "subvolume %llu is not set as snapshot but is not master subvolume",
+ k.k->p.offset)) {
+ struct bkey_i_subvolume *s =
+ bch2_bkey_make_mut_typed(trans, iter, &subvol.s_c, 0, subvolume);
+ ret = PTR_ERR_OR_ZERO(s);
+ if (ret)
+ return ret;
+
+ SET_BCH_SUBVOLUME_SNAP(&s->v, true);
+ }
+ }
+
+fsck_err:
+ return ret;
+}
+
+int bch2_check_subvols(struct bch_fs *c)
+{
+ int ret = bch2_trans_run(c,
+ for_each_btree_key_commit(trans, iter,
+ BTREE_ID_subvolumes, POS_MIN, BTREE_ITER_PREFETCH, k,
+ NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
+ check_subvol(trans, &iter, k)));
+ bch_err_fn(c, ret);
+ return ret;
+}
+
+/* Subvolumes: */
+
+int bch2_subvolume_invalid(struct bch_fs *c, struct bkey_s_c k,
+ enum bkey_invalid_flags flags, struct printbuf *err)
+{
+ int ret = 0;
+
+ bkey_fsck_err_on(bkey_lt(k.k->p, SUBVOL_POS_MIN) ||
+ bkey_gt(k.k->p, SUBVOL_POS_MAX), c, err,
+ subvol_pos_bad,
+ "invalid pos");
+fsck_err:
+ return ret;
+}
+
+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);
+
+ prt_printf(out, "root %llu snapshot id %u",
+ le64_to_cpu(s.v->inode),
+ le32_to_cpu(s.v->snapshot));
+
+ if (bkey_val_bytes(s.k) > offsetof(struct bch_subvolume, parent))
+ prt_printf(out, " parent %u", le32_to_cpu(s.v->parent));
+}
+
+static __always_inline int
+bch2_subvolume_get_inlined(struct btree_trans *trans, unsigned subvol,
+ bool inconsistent_if_not_found,
+ int iter_flags,
+ struct bch_subvolume *s)
+{
+ int ret = bch2_bkey_get_val_typed(trans, BTREE_ID_subvolumes, POS(0, subvol),
+ iter_flags, subvolume, s);
+ bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT) &&
+ inconsistent_if_not_found,
+ trans->c, "missing subvolume %u", subvol);
+ return ret;
+}
+
+int bch2_subvolume_get(struct btree_trans *trans, unsigned subvol,
+ bool inconsistent_if_not_found,
+ int iter_flags,
+ struct bch_subvolume *s)
+{
+ return bch2_subvolume_get_inlined(trans, subvol, inconsistent_if_not_found, iter_flags, s);
+}
+
+int bch2_subvol_is_ro_trans(struct btree_trans *trans, u32 subvol)
+{
+ struct bch_subvolume s;
+ int ret = bch2_subvolume_get_inlined(trans, subvol, true, 0, &s);
+ if (ret)
+ return ret;
+
+ if (BCH_SUBVOLUME_RO(&s))
+ return -EROFS;
+ return 0;
+}
+
+int bch2_subvol_is_ro(struct bch_fs *c, u32 subvol)
+{
+ return bch2_trans_do(c, NULL, NULL, 0,
+ bch2_subvol_is_ro_trans(trans, subvol));
+}
+
+int bch2_snapshot_get_subvol(struct btree_trans *trans, u32 snapshot,
+ struct bch_subvolume *subvol)
+{
+ struct bch_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 subvolid,
+ u32 *snapid)
+{
+ struct btree_iter iter;
+ struct bkey_s_c_subvolume subvol;
+ int ret;
+
+ 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(subvol.v->snapshot);
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+static int bch2_subvolume_reparent(struct btree_trans *trans,
+ struct btree_iter *iter,
+ struct bkey_s_c k,
+ u32 old_parent, u32 new_parent)
+{
+ struct bkey_i_subvolume *s;
+ int ret;
+
+ if (k.k->type != KEY_TYPE_subvolume)
+ return 0;
+
+ if (bkey_val_bytes(k.k) > offsetof(struct bch_subvolume, parent) &&
+ le32_to_cpu(bkey_s_c_to_subvolume(k).v->parent) != old_parent)
+ return 0;
+
+ s = bch2_bkey_make_mut_typed(trans, iter, &k, 0, subvolume);
+ ret = PTR_ERR_OR_ZERO(s);
+ if (ret)
+ return ret;
+
+ s->v.parent = cpu_to_le32(new_parent);
+ return 0;
+}
+
+/*
+ * 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)
+{
+ struct bch_subvolume s;
+
+ return lockrestart_do(trans,
+ bch2_subvolume_get(trans, subvolid_to_delete, true,
+ BTREE_ITER_CACHED, &s)) ?:
+ for_each_btree_key_commit(trans, iter,
+ BTREE_ID_subvolumes, POS_MIN, BTREE_ITER_PREFETCH, k,
+ NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
+ bch2_subvolume_reparent(trans, &iter, k,
+ subvolid_to_delete, le32_to_cpu(s.parent)));
+}
+
+/*
+ * Delete subvolume, mark snapshot ID as deleted, queue up snapshot
+ * deletion/cleanup:
+ */
+static int __bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
+{
+ struct btree_iter iter;
+ struct bkey_s_c_subvolume subvol;
+ u32 snapid;
+ int ret = 0;
+
+ subvol = bch2_bkey_get_iter_typed(trans, &iter,
+ BTREE_ID_subvolumes, POS(0, subvolid),
+ BTREE_ITER_CACHED|BTREE_ITER_INTENT,
+ subvolume);
+ ret = bkey_err(subvol);
+ bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
+ "missing subvolume %u", subvolid);
+ if (ret)
+ return ret;
+
+ snapid = le32_to_cpu(subvol.v->snapshot);
+
+ ret = bch2_btree_delete_at(trans, &iter, 0) ?:
+ bch2_snapshot_node_set_deleted(trans, snapid);
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+static int bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
+{
+ return bch2_subvolumes_reparent(trans, subvolid) ?:
+ commit_do(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
+ __bch2_subvolume_delete(trans, subvolid));
+}
+
+static void bch2_subvolume_wait_for_pagecache_and_delete(struct work_struct *work)
+{
+ struct bch_fs *c = container_of(work, struct bch_fs,
+ snapshot_wait_for_pagecache_and_delete_work);
+ snapshot_id_list s;
+ u32 *id;
+ int ret = 0;
+
+ while (!ret) {
+ mutex_lock(&c->snapshots_unlinked_lock);
+ s = c->snapshots_unlinked;
+ darray_init(&c->snapshots_unlinked);
+ mutex_unlock(&c->snapshots_unlinked_lock);
+
+ if (!s.nr)
+ break;
+
+ bch2_evict_subvolume_inodes(c, &s);
+
+ for (id = s.data; id < s.data + s.nr; id++) {
+ ret = bch2_trans_run(c, bch2_subvolume_delete(trans, *id));
+ bch_err_msg(c, ret, "deleting subvolume %u", *id);
+ if (ret)
+ break;
+ }
+
+ darray_exit(&s);
+ }
+
+ bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
+}
+
+struct subvolume_unlink_hook {
+ struct btree_trans_commit_hook h;
+ u32 subvol;
+};
+
+static int bch2_subvolume_wait_for_pagecache_and_delete_hook(struct btree_trans *trans,
+ struct btree_trans_commit_hook *_h)
+{
+ struct subvolume_unlink_hook *h = container_of(_h, struct subvolume_unlink_hook, h);
+ struct bch_fs *c = trans->c;
+ int ret = 0;
+
+ mutex_lock(&c->snapshots_unlinked_lock);
+ if (!snapshot_list_has_id(&c->snapshots_unlinked, h->subvol))
+ ret = snapshot_list_add(c, &c->snapshots_unlinked, h->subvol);
+ mutex_unlock(&c->snapshots_unlinked_lock);
+
+ if (ret)
+ return ret;
+
+ if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_snapshot_delete_pagecache))
+ return -EROFS;
+
+ if (!queue_work(c->write_ref_wq, &c->snapshot_wait_for_pagecache_and_delete_work))
+ bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
+ return 0;
+}
+
+int bch2_subvolume_unlink(struct btree_trans *trans, u32 subvolid)
+{
+ struct btree_iter iter;
+ struct bkey_i_subvolume *n;
+ struct subvolume_unlink_hook *h;
+ int ret = 0;
+
+ h = bch2_trans_kmalloc(trans, sizeof(*h));
+ ret = PTR_ERR_OR_ZERO(h);
+ if (ret)
+ return ret;
+
+ h->h.fn = bch2_subvolume_wait_for_pagecache_and_delete_hook;
+ h->subvol = subvolid;
+ bch2_trans_commit_hook(trans, &h->h);
+
+ n = bch2_bkey_get_mut_typed(trans, &iter,
+ BTREE_ID_subvolumes, POS(0, subvolid),
+ BTREE_ITER_CACHED, subvolume);
+ ret = PTR_ERR_OR_ZERO(n);
+ if (unlikely(ret)) {
+ bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
+ "missing subvolume %u", subvolid);
+ return ret;
+ }
+
+ SET_BCH_SUBVOLUME_UNLINKED(&n->v, true);
+ 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 bch_fs *c = trans->c;
+ 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;
+ u32 parent = 0, new_nodes[2], snapshot_subvols[2];
+ int ret = 0;
+
+ ret = bch2_bkey_get_empty_slot(trans, &dst_iter,
+ BTREE_ID_subvolumes, POS(0, U32_MAX));
+ if (ret == -BCH_ERR_ENOSPC_btree_slot)
+ ret = -BCH_ERR_ENOSPC_subvolume_create;
+ if (ret)
+ return ret;
+
+ snapshot_subvols[0] = dst_iter.pos.offset;
+ snapshot_subvols[1] = src_subvolid;
+
+ if (src_subvolid) {
+ /* Creating a snapshot: */
+
+ src_subvol = bch2_bkey_get_mut_typed(trans, &src_iter,
+ BTREE_ID_subvolumes, POS(0, src_subvolid),
+ BTREE_ITER_CACHED, subvolume);
+ ret = PTR_ERR_OR_ZERO(src_subvol);
+ if (unlikely(ret)) {
+ bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
+ "subvolume %u not found", src_subvolid);
+ goto err;
+ }
+
+ 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]);
+ ret = bch2_trans_update(trans, &src_iter, &src_subvol->k_i, 0);
+ if (ret)
+ goto err;
+ }
+
+ new_subvol = bch2_bkey_alloc(trans, &dst_iter, 0, subvolume);
+ ret = PTR_ERR_OR_ZERO(new_subvol);
+ if (ret)
+ goto err;
+
+ new_subvol->v.flags = 0;
+ new_subvol->v.snapshot = cpu_to_le32(new_nodes[0]);
+ new_subvol->v.inode = cpu_to_le64(inode);
+ new_subvol->v.parent = cpu_to_le32(src_subvolid);
+ new_subvol->v.otime.lo = cpu_to_le64(bch2_current_time(c));
+ new_subvol->v.otime.hi = 0;
+
+ SET_BCH_SUBVOLUME_RO(&new_subvol->v, ro);
+ SET_BCH_SUBVOLUME_SNAP(&new_subvol->v, src_subvolid != 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);
+ INIT_WORK(&c->snapshot_wait_for_pagecache_and_delete_work,
+ bch2_subvolume_wait_for_pagecache_and_delete);
+ mutex_init(&c->snapshots_unlinked_lock);
+ return 0;
+}
projects / bcachefs-tools-debian / blobdiff