1 // SPDX-License-Identifier: GPL-2.0
4 #include "btree_key_cache.h"
5 #include "btree_update.h"
10 #include "subvolume.h"
12 #include <linux/random.h>
14 static int bch2_subvolume_delete(struct btree_trans *, u32);
16 static int check_subvol(struct btree_trans *trans,
17 struct btree_iter *iter,
20 struct bch_fs *c = trans->c;
21 struct bkey_s_c_subvolume subvol;
22 struct bch_snapshot snapshot;
26 if (k.k->type != KEY_TYPE_subvolume)
29 subvol = bkey_s_c_to_subvolume(k);
30 snapid = le32_to_cpu(subvol.v->snapshot);
31 ret = bch2_snapshot_lookup(trans, snapid, &snapshot);
33 if (bch2_err_matches(ret, ENOENT))
34 bch_err(c, "subvolume %llu points to nonexistent snapshot %u",
35 k.k->p.offset, snapid);
39 if (BCH_SUBVOLUME_UNLINKED(subvol.v)) {
42 ret = bch2_subvolume_delete(trans, iter->pos.offset);
44 bch_err(c, "error deleting subvolume %llu: %s",
45 iter->pos.offset, bch2_err_str(ret));
46 return ret ?: -BCH_ERR_transaction_restart_nested;
49 if (!BCH_SUBVOLUME_SNAP(subvol.v)) {
50 u32 snapshot_root = bch2_snapshot_root(c, le32_to_cpu(subvol.v->snapshot));
52 struct bch_snapshot_tree st;
55 snapshot_tree = snapshot_t(c, snapshot_root)->tree;
58 ret = bch2_snapshot_tree_lookup(trans, snapshot_tree, &st);
60 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
61 "%s: snapshot tree %u not found", __func__, snapshot_tree);
66 if (fsck_err_on(le32_to_cpu(st.master_subvol) != subvol.k->p.offset, c,
67 "subvolume %llu is not set as snapshot but is not master subvolume",
69 struct bkey_i_subvolume *s =
70 bch2_bkey_make_mut_typed(trans, iter, &subvol.s_c, 0, subvolume);
71 ret = PTR_ERR_OR_ZERO(s);
75 SET_BCH_SUBVOLUME_SNAP(&s->v, true);
83 int bch2_check_subvols(struct bch_fs *c)
85 struct btree_iter iter;
89 ret = bch2_trans_run(c,
90 for_each_btree_key_commit(&trans, iter,
91 BTREE_ID_subvolumes, POS_MIN, BTREE_ITER_PREFETCH, k,
92 NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
93 check_subvol(&trans, &iter, k)));
101 int bch2_subvolume_invalid(const struct bch_fs *c, struct bkey_s_c k,
102 unsigned flags, struct printbuf *err)
104 if (bkey_lt(k.k->p, SUBVOL_POS_MIN) ||
105 bkey_gt(k.k->p, SUBVOL_POS_MAX)) {
106 prt_printf(err, "invalid pos");
107 return -BCH_ERR_invalid_bkey;
113 void bch2_subvolume_to_text(struct printbuf *out, struct bch_fs *c,
116 struct bkey_s_c_subvolume s = bkey_s_c_to_subvolume(k);
118 prt_printf(out, "root %llu snapshot id %u",
119 le64_to_cpu(s.v->inode),
120 le32_to_cpu(s.v->snapshot));
122 if (bkey_val_bytes(s.k) > offsetof(struct bch_subvolume, parent))
123 prt_printf(out, " parent %u", le32_to_cpu(s.v->parent));
126 static __always_inline int
127 bch2_subvolume_get_inlined(struct btree_trans *trans, unsigned subvol,
128 bool inconsistent_if_not_found,
130 struct bch_subvolume *s)
132 int ret = bch2_bkey_get_val_typed(trans, BTREE_ID_subvolumes, POS(0, subvol),
133 iter_flags, subvolume, s);
134 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT) &&
135 inconsistent_if_not_found,
136 trans->c, "missing subvolume %u", subvol);
140 int bch2_subvolume_get(struct btree_trans *trans, unsigned subvol,
141 bool inconsistent_if_not_found,
143 struct bch_subvolume *s)
145 return bch2_subvolume_get_inlined(trans, subvol, inconsistent_if_not_found, iter_flags, s);
148 int bch2_snapshot_get_subvol(struct btree_trans *trans, u32 snapshot,
149 struct bch_subvolume *subvol)
151 struct bch_snapshot snap;
153 return bch2_snapshot_lookup(trans, snapshot, &snap) ?:
154 bch2_subvolume_get(trans, le32_to_cpu(snap.subvol), true, 0, subvol);
157 int bch2_subvolume_get_snapshot(struct btree_trans *trans, u32 subvolid,
160 struct btree_iter iter;
161 struct bkey_s_c_subvolume subvol;
164 subvol = bch2_bkey_get_iter_typed(trans, &iter,
165 BTREE_ID_subvolumes, POS(0, subvolid),
166 BTREE_ITER_CACHED|BTREE_ITER_WITH_UPDATES,
168 ret = bkey_err(subvol);
169 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
170 "missing subvolume %u", subvolid);
173 *snapid = le32_to_cpu(subvol.v->snapshot);
174 bch2_trans_iter_exit(trans, &iter);
178 static int bch2_subvolume_reparent(struct btree_trans *trans,
179 struct btree_iter *iter,
181 u32 old_parent, u32 new_parent)
183 struct bkey_i_subvolume *s;
186 if (k.k->type != KEY_TYPE_subvolume)
189 if (bkey_val_bytes(k.k) > offsetof(struct bch_subvolume, parent) &&
190 le32_to_cpu(bkey_s_c_to_subvolume(k).v->parent) != old_parent)
193 s = bch2_bkey_make_mut_typed(trans, iter, &k, 0, subvolume);
194 ret = PTR_ERR_OR_ZERO(s);
198 s->v.parent = cpu_to_le32(new_parent);
203 * Separate from the snapshot tree in the snapshots btree, we record the tree
204 * structure of how snapshot subvolumes were created - the parent subvolume of
205 * each snapshot subvolume.
207 * When a subvolume is deleted, we scan for child subvolumes and reparant them,
208 * to avoid dangling references:
210 static int bch2_subvolumes_reparent(struct btree_trans *trans, u32 subvolid_to_delete)
212 struct btree_iter iter;
214 struct bch_subvolume s;
216 return lockrestart_do(trans,
217 bch2_subvolume_get(trans, subvolid_to_delete, true,
218 BTREE_ITER_CACHED, &s)) ?:
219 for_each_btree_key_commit(trans, iter,
220 BTREE_ID_subvolumes, POS_MIN, BTREE_ITER_PREFETCH, k,
221 NULL, NULL, BTREE_INSERT_NOFAIL,
222 bch2_subvolume_reparent(trans, &iter, k,
223 subvolid_to_delete, le32_to_cpu(s.parent)));
227 * Delete subvolume, mark snapshot ID as deleted, queue up snapshot
230 static int __bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
232 struct btree_iter iter;
233 struct bkey_s_c_subvolume subvol;
234 struct btree_trans_commit_hook *h;
238 subvol = bch2_bkey_get_iter_typed(trans, &iter,
239 BTREE_ID_subvolumes, POS(0, subvolid),
240 BTREE_ITER_CACHED|BTREE_ITER_INTENT,
242 ret = bkey_err(subvol);
243 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
244 "missing subvolume %u", subvolid);
248 snapid = le32_to_cpu(subvol.v->snapshot);
250 ret = bch2_btree_delete_at(trans, &iter, 0);
254 ret = bch2_snapshot_node_set_deleted(trans, snapid);
258 h = bch2_trans_kmalloc(trans, sizeof(*h));
259 ret = PTR_ERR_OR_ZERO(h);
263 h->fn = bch2_delete_dead_snapshots_hook;
264 bch2_trans_commit_hook(trans, h);
266 bch2_trans_iter_exit(trans, &iter);
270 static int bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
272 return bch2_subvolumes_reparent(trans, subvolid) ?:
273 commit_do(trans, NULL, NULL, BTREE_INSERT_NOFAIL,
274 __bch2_subvolume_delete(trans, subvolid));
277 static void bch2_subvolume_wait_for_pagecache_and_delete(struct work_struct *work)
279 struct bch_fs *c = container_of(work, struct bch_fs,
280 snapshot_wait_for_pagecache_and_delete_work);
286 mutex_lock(&c->snapshots_unlinked_lock);
287 s = c->snapshots_unlinked;
288 darray_init(&c->snapshots_unlinked);
289 mutex_unlock(&c->snapshots_unlinked_lock);
294 bch2_evict_subvolume_inodes(c, &s);
296 for (id = s.data; id < s.data + s.nr; id++) {
297 ret = bch2_trans_run(c, bch2_subvolume_delete(&trans, *id));
299 bch_err(c, "error deleting subvolume %u: %s", *id, bch2_err_str(ret));
307 bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
310 struct subvolume_unlink_hook {
311 struct btree_trans_commit_hook h;
315 static int bch2_subvolume_wait_for_pagecache_and_delete_hook(struct btree_trans *trans,
316 struct btree_trans_commit_hook *_h)
318 struct subvolume_unlink_hook *h = container_of(_h, struct subvolume_unlink_hook, h);
319 struct bch_fs *c = trans->c;
322 mutex_lock(&c->snapshots_unlinked_lock);
323 if (!snapshot_list_has_id(&c->snapshots_unlinked, h->subvol))
324 ret = snapshot_list_add(c, &c->snapshots_unlinked, h->subvol);
325 mutex_unlock(&c->snapshots_unlinked_lock);
330 if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_snapshot_delete_pagecache))
333 if (!queue_work(c->write_ref_wq, &c->snapshot_wait_for_pagecache_and_delete_work))
334 bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
338 int bch2_subvolume_unlink(struct btree_trans *trans, u32 subvolid)
340 struct btree_iter iter;
341 struct bkey_i_subvolume *n;
342 struct subvolume_unlink_hook *h;
345 h = bch2_trans_kmalloc(trans, sizeof(*h));
346 ret = PTR_ERR_OR_ZERO(h);
350 h->h.fn = bch2_subvolume_wait_for_pagecache_and_delete_hook;
351 h->subvol = subvolid;
352 bch2_trans_commit_hook(trans, &h->h);
354 n = bch2_bkey_get_mut_typed(trans, &iter,
355 BTREE_ID_subvolumes, POS(0, subvolid),
356 BTREE_ITER_CACHED, subvolume);
357 ret = PTR_ERR_OR_ZERO(n);
359 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
360 "missing subvolume %u", subvolid);
364 SET_BCH_SUBVOLUME_UNLINKED(&n->v, true);
365 bch2_trans_iter_exit(trans, &iter);
369 int bch2_subvolume_create(struct btree_trans *trans, u64 inode,
375 struct bch_fs *c = trans->c;
376 struct btree_iter dst_iter, src_iter = (struct btree_iter) { NULL };
377 struct bkey_i_subvolume *new_subvol = NULL;
378 struct bkey_i_subvolume *src_subvol = NULL;
379 u32 parent = 0, new_nodes[2], snapshot_subvols[2];
382 ret = bch2_bkey_get_empty_slot(trans, &dst_iter,
383 BTREE_ID_subvolumes, POS(0, U32_MAX));
384 if (ret == -BCH_ERR_ENOSPC_btree_slot)
385 ret = -BCH_ERR_ENOSPC_subvolume_create;
389 snapshot_subvols[0] = dst_iter.pos.offset;
390 snapshot_subvols[1] = src_subvolid;
393 /* Creating a snapshot: */
395 src_subvol = bch2_bkey_get_mut_typed(trans, &src_iter,
396 BTREE_ID_subvolumes, POS(0, src_subvolid),
397 BTREE_ITER_CACHED, subvolume);
398 ret = PTR_ERR_OR_ZERO(src_subvol);
400 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
401 "subvolume %u not found", src_subvolid);
405 parent = le32_to_cpu(src_subvol->v.snapshot);
408 ret = bch2_snapshot_node_create(trans, parent, new_nodes,
410 src_subvolid ? 2 : 1);
415 src_subvol->v.snapshot = cpu_to_le32(new_nodes[1]);
416 ret = bch2_trans_update(trans, &src_iter, &src_subvol->k_i, 0);
421 new_subvol = bch2_bkey_alloc(trans, &dst_iter, 0, subvolume);
422 ret = PTR_ERR_OR_ZERO(new_subvol);
426 new_subvol->v.flags = 0;
427 new_subvol->v.snapshot = cpu_to_le32(new_nodes[0]);
428 new_subvol->v.inode = cpu_to_le64(inode);
429 new_subvol->v.parent = cpu_to_le32(src_subvolid);
430 new_subvol->v.otime.lo = cpu_to_le64(bch2_current_time(c));
431 new_subvol->v.otime.hi = 0;
433 SET_BCH_SUBVOLUME_RO(&new_subvol->v, ro);
434 SET_BCH_SUBVOLUME_SNAP(&new_subvol->v, src_subvolid != 0);
436 *new_subvolid = new_subvol->k.p.offset;
437 *new_snapshotid = new_nodes[0];
439 bch2_trans_iter_exit(trans, &src_iter);
440 bch2_trans_iter_exit(trans, &dst_iter);
444 int bch2_fs_subvolumes_init(struct bch_fs *c)
446 INIT_WORK(&c->snapshot_delete_work, bch2_delete_dead_snapshots_work);
447 INIT_WORK(&c->snapshot_wait_for_pagecache_and_delete_work,
448 bch2_subvolume_wait_for_pagecache_and_delete);
449 mutex_init(&c->snapshots_unlinked_lock);