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_msg(c, ret, "deleting subvolume %llu", iter->pos.offset);
45 return ret ?: -BCH_ERR_transaction_restart_nested;
48 if (!BCH_SUBVOLUME_SNAP(subvol.v)) {
49 u32 snapshot_root = bch2_snapshot_root(c, le32_to_cpu(subvol.v->snapshot));
51 struct bch_snapshot_tree st;
54 snapshot_tree = snapshot_t(c, snapshot_root)->tree;
57 ret = bch2_snapshot_tree_lookup(trans, snapshot_tree, &st);
59 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
60 "%s: snapshot tree %u not found", __func__, snapshot_tree);
65 if (fsck_err_on(le32_to_cpu(st.master_subvol) != subvol.k->p.offset, c,
66 "subvolume %llu is not set as snapshot but is not master subvolume",
68 struct bkey_i_subvolume *s =
69 bch2_bkey_make_mut_typed(trans, iter, &subvol.s_c, 0, subvolume);
70 ret = PTR_ERR_OR_ZERO(s);
74 SET_BCH_SUBVOLUME_SNAP(&s->v, true);
82 int bch2_check_subvols(struct bch_fs *c)
84 struct btree_iter iter;
88 ret = bch2_trans_run(c,
89 for_each_btree_key_commit(trans, iter,
90 BTREE_ID_subvolumes, POS_MIN, BTREE_ITER_PREFETCH, k,
91 NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
92 check_subvol(trans, &iter, k)));
100 int bch2_subvolume_invalid(const struct bch_fs *c, struct bkey_s_c k,
101 enum bkey_invalid_flags flags, struct printbuf *err)
103 if (bkey_lt(k.k->p, SUBVOL_POS_MIN) ||
104 bkey_gt(k.k->p, SUBVOL_POS_MAX)) {
105 prt_printf(err, "invalid pos");
106 return -BCH_ERR_invalid_bkey;
112 void bch2_subvolume_to_text(struct printbuf *out, struct bch_fs *c,
115 struct bkey_s_c_subvolume s = bkey_s_c_to_subvolume(k);
117 prt_printf(out, "root %llu snapshot id %u",
118 le64_to_cpu(s.v->inode),
119 le32_to_cpu(s.v->snapshot));
121 if (bkey_val_bytes(s.k) > offsetof(struct bch_subvolume, parent))
122 prt_printf(out, " parent %u", le32_to_cpu(s.v->parent));
125 static __always_inline int
126 bch2_subvolume_get_inlined(struct btree_trans *trans, unsigned subvol,
127 bool inconsistent_if_not_found,
129 struct bch_subvolume *s)
131 int ret = bch2_bkey_get_val_typed(trans, BTREE_ID_subvolumes, POS(0, subvol),
132 iter_flags, subvolume, s);
133 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT) &&
134 inconsistent_if_not_found,
135 trans->c, "missing subvolume %u", subvol);
139 int bch2_subvolume_get(struct btree_trans *trans, unsigned subvol,
140 bool inconsistent_if_not_found,
142 struct bch_subvolume *s)
144 return bch2_subvolume_get_inlined(trans, subvol, inconsistent_if_not_found, iter_flags, s);
147 int bch2_snapshot_get_subvol(struct btree_trans *trans, u32 snapshot,
148 struct bch_subvolume *subvol)
150 struct bch_snapshot snap;
152 return bch2_snapshot_lookup(trans, snapshot, &snap) ?:
153 bch2_subvolume_get(trans, le32_to_cpu(snap.subvol), true, 0, subvol);
156 int bch2_subvolume_get_snapshot(struct btree_trans *trans, u32 subvolid,
159 struct btree_iter iter;
160 struct bkey_s_c_subvolume subvol;
163 subvol = bch2_bkey_get_iter_typed(trans, &iter,
164 BTREE_ID_subvolumes, POS(0, subvolid),
165 BTREE_ITER_CACHED|BTREE_ITER_WITH_UPDATES,
167 ret = bkey_err(subvol);
168 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
169 "missing subvolume %u", subvolid);
172 *snapid = le32_to_cpu(subvol.v->snapshot);
173 bch2_trans_iter_exit(trans, &iter);
177 static int bch2_subvolume_reparent(struct btree_trans *trans,
178 struct btree_iter *iter,
180 u32 old_parent, u32 new_parent)
182 struct bkey_i_subvolume *s;
185 if (k.k->type != KEY_TYPE_subvolume)
188 if (bkey_val_bytes(k.k) > offsetof(struct bch_subvolume, parent) &&
189 le32_to_cpu(bkey_s_c_to_subvolume(k).v->parent) != old_parent)
192 s = bch2_bkey_make_mut_typed(trans, iter, &k, 0, subvolume);
193 ret = PTR_ERR_OR_ZERO(s);
197 s->v.parent = cpu_to_le32(new_parent);
202 * Separate from the snapshot tree in the snapshots btree, we record the tree
203 * structure of how snapshot subvolumes were created - the parent subvolume of
204 * each snapshot subvolume.
206 * When a subvolume is deleted, we scan for child subvolumes and reparant them,
207 * to avoid dangling references:
209 static int bch2_subvolumes_reparent(struct btree_trans *trans, u32 subvolid_to_delete)
211 struct btree_iter iter;
213 struct bch_subvolume s;
215 return lockrestart_do(trans,
216 bch2_subvolume_get(trans, subvolid_to_delete, true,
217 BTREE_ITER_CACHED, &s)) ?:
218 for_each_btree_key_commit(trans, iter,
219 BTREE_ID_subvolumes, POS_MIN, BTREE_ITER_PREFETCH, k,
220 NULL, NULL, BTREE_INSERT_NOFAIL,
221 bch2_subvolume_reparent(trans, &iter, k,
222 subvolid_to_delete, le32_to_cpu(s.parent)));
226 * Delete subvolume, mark snapshot ID as deleted, queue up snapshot
229 static int __bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
231 struct btree_iter iter;
232 struct bkey_s_c_subvolume subvol;
233 struct btree_trans_commit_hook *h;
237 subvol = bch2_bkey_get_iter_typed(trans, &iter,
238 BTREE_ID_subvolumes, POS(0, subvolid),
239 BTREE_ITER_CACHED|BTREE_ITER_INTENT,
241 ret = bkey_err(subvol);
242 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
243 "missing subvolume %u", subvolid);
247 snapid = le32_to_cpu(subvol.v->snapshot);
249 ret = bch2_btree_delete_at(trans, &iter, 0);
253 ret = bch2_snapshot_node_set_deleted(trans, snapid);
257 h = bch2_trans_kmalloc(trans, sizeof(*h));
258 ret = PTR_ERR_OR_ZERO(h);
262 h->fn = bch2_delete_dead_snapshots_hook;
263 bch2_trans_commit_hook(trans, h);
265 bch2_trans_iter_exit(trans, &iter);
269 static int bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
271 return bch2_subvolumes_reparent(trans, subvolid) ?:
272 commit_do(trans, NULL, NULL, BTREE_INSERT_NOFAIL,
273 __bch2_subvolume_delete(trans, subvolid));
276 static void bch2_subvolume_wait_for_pagecache_and_delete(struct work_struct *work)
278 struct bch_fs *c = container_of(work, struct bch_fs,
279 snapshot_wait_for_pagecache_and_delete_work);
285 mutex_lock(&c->snapshots_unlinked_lock);
286 s = c->snapshots_unlinked;
287 darray_init(&c->snapshots_unlinked);
288 mutex_unlock(&c->snapshots_unlinked_lock);
293 bch2_evict_subvolume_inodes(c, &s);
295 for (id = s.data; id < s.data + s.nr; id++) {
296 ret = bch2_trans_run(c, bch2_subvolume_delete(trans, *id));
298 bch_err_msg(c, ret, "deleting subvolume %u", *id);
306 bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
309 struct subvolume_unlink_hook {
310 struct btree_trans_commit_hook h;
314 static int bch2_subvolume_wait_for_pagecache_and_delete_hook(struct btree_trans *trans,
315 struct btree_trans_commit_hook *_h)
317 struct subvolume_unlink_hook *h = container_of(_h, struct subvolume_unlink_hook, h);
318 struct bch_fs *c = trans->c;
321 mutex_lock(&c->snapshots_unlinked_lock);
322 if (!snapshot_list_has_id(&c->snapshots_unlinked, h->subvol))
323 ret = snapshot_list_add(c, &c->snapshots_unlinked, h->subvol);
324 mutex_unlock(&c->snapshots_unlinked_lock);
329 if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_snapshot_delete_pagecache))
332 if (!queue_work(c->write_ref_wq, &c->snapshot_wait_for_pagecache_and_delete_work))
333 bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
337 int bch2_subvolume_unlink(struct btree_trans *trans, u32 subvolid)
339 struct btree_iter iter;
340 struct bkey_i_subvolume *n;
341 struct subvolume_unlink_hook *h;
344 h = bch2_trans_kmalloc(trans, sizeof(*h));
345 ret = PTR_ERR_OR_ZERO(h);
349 h->h.fn = bch2_subvolume_wait_for_pagecache_and_delete_hook;
350 h->subvol = subvolid;
351 bch2_trans_commit_hook(trans, &h->h);
353 n = bch2_bkey_get_mut_typed(trans, &iter,
354 BTREE_ID_subvolumes, POS(0, subvolid),
355 BTREE_ITER_CACHED, subvolume);
356 ret = PTR_ERR_OR_ZERO(n);
358 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
359 "missing subvolume %u", subvolid);
363 SET_BCH_SUBVOLUME_UNLINKED(&n->v, true);
364 bch2_trans_iter_exit(trans, &iter);
368 int bch2_subvolume_create(struct btree_trans *trans, u64 inode,
374 struct bch_fs *c = trans->c;
375 struct btree_iter dst_iter, src_iter = (struct btree_iter) { NULL };
376 struct bkey_i_subvolume *new_subvol = NULL;
377 struct bkey_i_subvolume *src_subvol = NULL;
378 u32 parent = 0, new_nodes[2], snapshot_subvols[2];
381 ret = bch2_bkey_get_empty_slot(trans, &dst_iter,
382 BTREE_ID_subvolumes, POS(0, U32_MAX));
383 if (ret == -BCH_ERR_ENOSPC_btree_slot)
384 ret = -BCH_ERR_ENOSPC_subvolume_create;
388 snapshot_subvols[0] = dst_iter.pos.offset;
389 snapshot_subvols[1] = src_subvolid;
392 /* Creating a snapshot: */
394 src_subvol = bch2_bkey_get_mut_typed(trans, &src_iter,
395 BTREE_ID_subvolumes, POS(0, src_subvolid),
396 BTREE_ITER_CACHED, subvolume);
397 ret = PTR_ERR_OR_ZERO(src_subvol);
399 bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
400 "subvolume %u not found", src_subvolid);
404 parent = le32_to_cpu(src_subvol->v.snapshot);
407 ret = bch2_snapshot_node_create(trans, parent, new_nodes,
409 src_subvolid ? 2 : 1);
414 src_subvol->v.snapshot = cpu_to_le32(new_nodes[1]);
415 ret = bch2_trans_update(trans, &src_iter, &src_subvol->k_i, 0);
420 new_subvol = bch2_bkey_alloc(trans, &dst_iter, 0, subvolume);
421 ret = PTR_ERR_OR_ZERO(new_subvol);
425 new_subvol->v.flags = 0;
426 new_subvol->v.snapshot = cpu_to_le32(new_nodes[0]);
427 new_subvol->v.inode = cpu_to_le64(inode);
428 new_subvol->v.parent = cpu_to_le32(src_subvolid);
429 new_subvol->v.otime.lo = cpu_to_le64(bch2_current_time(c));
430 new_subvol->v.otime.hi = 0;
432 SET_BCH_SUBVOLUME_RO(&new_subvol->v, ro);
433 SET_BCH_SUBVOLUME_SNAP(&new_subvol->v, src_subvolid != 0);
435 *new_subvolid = new_subvol->k.p.offset;
436 *new_snapshotid = new_nodes[0];
438 bch2_trans_iter_exit(trans, &src_iter);
439 bch2_trans_iter_exit(trans, &dst_iter);
443 int bch2_fs_subvolumes_init(struct bch_fs *c)
445 INIT_WORK(&c->snapshot_delete_work, bch2_delete_dead_snapshots_work);
446 INIT_WORK(&c->snapshot_wait_for_pagecache_and_delete_work,
447 bch2_subvolume_wait_for_pagecache_and_delete);
448 mutex_init(&c->snapshots_unlinked_lock);