Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Copyright (C) 2007 Oracle. All rights reserved.
4 : */
5 :
6 : #include <linux/err.h>
7 : #include <linux/uuid.h>
8 : #include "ctree.h"
9 : #include "fs.h"
10 : #include "messages.h"
11 : #include "transaction.h"
12 : #include "disk-io.h"
13 : #include "print-tree.h"
14 : #include "qgroup.h"
15 : #include "space-info.h"
16 : #include "accessors.h"
17 : #include "root-tree.h"
18 : #include "orphan.h"
19 :
20 : /*
21 : * Read a root item from the tree. In case we detect a root item smaller then
22 : * sizeof(root_item), we know it's an old version of the root structure and
23 : * initialize all new fields to zero. The same happens if we detect mismatching
24 : * generation numbers as then we know the root was once mounted with an older
25 : * kernel that was not aware of the root item structure change.
26 : */
27 0 : static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
28 : struct btrfs_root_item *item)
29 : {
30 0 : u32 len;
31 0 : int need_reset = 0;
32 :
33 0 : len = btrfs_item_size(eb, slot);
34 0 : read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
35 0 : min_t(u32, len, sizeof(*item)));
36 0 : if (len < sizeof(*item))
37 : need_reset = 1;
38 0 : if (!need_reset && btrfs_root_generation(item)
39 : != btrfs_root_generation_v2(item)) {
40 0 : if (btrfs_root_generation_v2(item) != 0) {
41 0 : btrfs_warn(eb->fs_info,
42 : "mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.");
43 : }
44 : need_reset = 1;
45 : }
46 0 : if (need_reset) {
47 : /* Clear all members from generation_v2 onwards. */
48 0 : memset_startat(item, 0, generation_v2);
49 0 : generate_random_guid(item->uuid);
50 : }
51 0 : }
52 :
53 : /*
54 : * btrfs_find_root - lookup the root by the key.
55 : * root: the root of the root tree
56 : * search_key: the key to search
57 : * path: the path we search
58 : * root_item: the root item of the tree we look for
59 : * root_key: the root key of the tree we look for
60 : *
61 : * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset
62 : * of the search key, just lookup the root with the highest offset for a
63 : * given objectid.
64 : *
65 : * If we find something return 0, otherwise > 0, < 0 on error.
66 : */
67 0 : int btrfs_find_root(struct btrfs_root *root, const struct btrfs_key *search_key,
68 : struct btrfs_path *path, struct btrfs_root_item *root_item,
69 : struct btrfs_key *root_key)
70 : {
71 0 : struct btrfs_key found_key;
72 0 : struct extent_buffer *l;
73 0 : int ret;
74 0 : int slot;
75 :
76 0 : ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
77 0 : if (ret < 0)
78 : return ret;
79 :
80 0 : if (search_key->offset != -1ULL) { /* the search key is exact */
81 0 : if (ret > 0)
82 0 : goto out;
83 : } else {
84 0 : BUG_ON(ret == 0); /* Logical error */
85 0 : if (path->slots[0] == 0)
86 0 : goto out;
87 0 : path->slots[0]--;
88 0 : ret = 0;
89 : }
90 :
91 0 : l = path->nodes[0];
92 0 : slot = path->slots[0];
93 :
94 0 : btrfs_item_key_to_cpu(l, &found_key, slot);
95 0 : if (found_key.objectid != search_key->objectid ||
96 0 : found_key.type != BTRFS_ROOT_ITEM_KEY) {
97 0 : ret = 1;
98 0 : goto out;
99 : }
100 :
101 0 : if (root_item)
102 0 : btrfs_read_root_item(l, slot, root_item);
103 0 : if (root_key)
104 0 : memcpy(root_key, &found_key, sizeof(found_key));
105 0 : out:
106 0 : btrfs_release_path(path);
107 0 : return ret;
108 : }
109 :
110 0 : void btrfs_set_root_node(struct btrfs_root_item *item,
111 : struct extent_buffer *node)
112 : {
113 0 : btrfs_set_root_bytenr(item, node->start);
114 0 : btrfs_set_root_level(item, btrfs_header_level(node));
115 0 : btrfs_set_root_generation(item, btrfs_header_generation(node));
116 0 : }
117 :
118 : /*
119 : * copy the data in 'item' into the btree
120 : */
121 0 : int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
122 : *root, struct btrfs_key *key, struct btrfs_root_item
123 : *item)
124 : {
125 0 : struct btrfs_fs_info *fs_info = root->fs_info;
126 0 : struct btrfs_path *path;
127 0 : struct extent_buffer *l;
128 0 : int ret;
129 0 : int slot;
130 0 : unsigned long ptr;
131 0 : u32 old_len;
132 :
133 0 : path = btrfs_alloc_path();
134 0 : if (!path)
135 : return -ENOMEM;
136 :
137 0 : ret = btrfs_search_slot(trans, root, key, path, 0, 1);
138 0 : if (ret < 0)
139 0 : goto out;
140 :
141 0 : if (ret > 0) {
142 0 : btrfs_crit(fs_info,
143 : "unable to find root key (%llu %u %llu) in tree %llu",
144 : key->objectid, key->type, key->offset,
145 : root->root_key.objectid);
146 0 : ret = -EUCLEAN;
147 0 : btrfs_abort_transaction(trans, ret);
148 0 : goto out;
149 : }
150 :
151 0 : l = path->nodes[0];
152 0 : slot = path->slots[0];
153 0 : ptr = btrfs_item_ptr_offset(l, slot);
154 0 : old_len = btrfs_item_size(l, slot);
155 :
156 : /*
157 : * If this is the first time we update the root item which originated
158 : * from an older kernel, we need to enlarge the item size to make room
159 : * for the added fields.
160 : */
161 0 : if (old_len < sizeof(*item)) {
162 0 : btrfs_release_path(path);
163 0 : ret = btrfs_search_slot(trans, root, key, path,
164 : -1, 1);
165 0 : if (ret < 0) {
166 0 : btrfs_abort_transaction(trans, ret);
167 0 : goto out;
168 : }
169 :
170 0 : ret = btrfs_del_item(trans, root, path);
171 0 : if (ret < 0) {
172 0 : btrfs_abort_transaction(trans, ret);
173 0 : goto out;
174 : }
175 0 : btrfs_release_path(path);
176 0 : ret = btrfs_insert_empty_item(trans, root, path,
177 : key, sizeof(*item));
178 0 : if (ret < 0) {
179 0 : btrfs_abort_transaction(trans, ret);
180 0 : goto out;
181 : }
182 0 : l = path->nodes[0];
183 0 : slot = path->slots[0];
184 0 : ptr = btrfs_item_ptr_offset(l, slot);
185 : }
186 :
187 : /*
188 : * Update generation_v2 so at the next mount we know the new root
189 : * fields are valid.
190 : */
191 0 : btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
192 :
193 0 : write_extent_buffer(l, item, ptr, sizeof(*item));
194 0 : btrfs_mark_buffer_dirty(path->nodes[0]);
195 0 : out:
196 0 : btrfs_free_path(path);
197 0 : return ret;
198 : }
199 :
200 0 : int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
201 : const struct btrfs_key *key, struct btrfs_root_item *item)
202 : {
203 : /*
204 : * Make sure generation v1 and v2 match. See update_root for details.
205 : */
206 0 : btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
207 0 : return btrfs_insert_item(trans, root, key, item, sizeof(*item));
208 : }
209 :
210 0 : int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
211 : {
212 0 : struct btrfs_root *tree_root = fs_info->tree_root;
213 0 : struct extent_buffer *leaf;
214 0 : struct btrfs_path *path;
215 0 : struct btrfs_key key;
216 0 : struct btrfs_root *root;
217 0 : int err = 0;
218 0 : int ret;
219 :
220 0 : path = btrfs_alloc_path();
221 0 : if (!path)
222 : return -ENOMEM;
223 :
224 0 : key.objectid = BTRFS_ORPHAN_OBJECTID;
225 0 : key.type = BTRFS_ORPHAN_ITEM_KEY;
226 0 : key.offset = 0;
227 :
228 0 : while (1) {
229 0 : u64 root_objectid;
230 :
231 0 : ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
232 0 : if (ret < 0) {
233 : err = ret;
234 : break;
235 : }
236 :
237 0 : leaf = path->nodes[0];
238 0 : if (path->slots[0] >= btrfs_header_nritems(leaf)) {
239 0 : ret = btrfs_next_leaf(tree_root, path);
240 0 : if (ret < 0)
241 : err = ret;
242 0 : if (ret != 0)
243 : break;
244 0 : leaf = path->nodes[0];
245 : }
246 :
247 0 : btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
248 0 : btrfs_release_path(path);
249 :
250 0 : if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
251 0 : key.type != BTRFS_ORPHAN_ITEM_KEY)
252 : break;
253 :
254 0 : root_objectid = key.offset;
255 0 : key.offset++;
256 :
257 0 : root = btrfs_get_fs_root(fs_info, root_objectid, false);
258 0 : err = PTR_ERR_OR_ZERO(root);
259 0 : if (err && err != -ENOENT) {
260 : break;
261 0 : } else if (err == -ENOENT) {
262 0 : struct btrfs_trans_handle *trans;
263 :
264 0 : btrfs_release_path(path);
265 :
266 0 : trans = btrfs_join_transaction(tree_root);
267 0 : if (IS_ERR(trans)) {
268 0 : err = PTR_ERR(trans);
269 0 : btrfs_handle_fs_error(fs_info, err,
270 : "Failed to start trans to delete orphan item");
271 0 : break;
272 : }
273 0 : err = btrfs_del_orphan_item(trans, tree_root,
274 : root_objectid);
275 0 : btrfs_end_transaction(trans);
276 0 : if (err) {
277 0 : btrfs_handle_fs_error(fs_info, err,
278 : "Failed to delete root orphan item");
279 0 : break;
280 : }
281 0 : continue;
282 : }
283 :
284 0 : WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state));
285 0 : if (btrfs_root_refs(&root->root_item) == 0) {
286 0 : struct btrfs_key drop_key;
287 :
288 0 : btrfs_disk_key_to_cpu(&drop_key, &root->root_item.drop_progress);
289 : /*
290 : * If we have a non-zero drop_progress then we know we
291 : * made it partly through deleting this snapshot, and
292 : * thus we need to make sure we block any balance from
293 : * happening until this snapshot is completely dropped.
294 : */
295 0 : if (drop_key.objectid != 0 || drop_key.type != 0 ||
296 0 : drop_key.offset != 0) {
297 0 : set_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);
298 0 : set_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);
299 : }
300 :
301 0 : set_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
302 0 : btrfs_add_dead_root(root);
303 : }
304 0 : btrfs_put_root(root);
305 : }
306 :
307 0 : btrfs_free_path(path);
308 0 : return err;
309 : }
310 :
311 : /* drop the root item for 'key' from the tree root */
312 0 : int btrfs_del_root(struct btrfs_trans_handle *trans,
313 : const struct btrfs_key *key)
314 : {
315 0 : struct btrfs_root *root = trans->fs_info->tree_root;
316 0 : struct btrfs_path *path;
317 0 : int ret;
318 :
319 0 : path = btrfs_alloc_path();
320 0 : if (!path)
321 : return -ENOMEM;
322 0 : ret = btrfs_search_slot(trans, root, key, path, -1, 1);
323 0 : if (ret < 0)
324 0 : goto out;
325 :
326 0 : BUG_ON(ret != 0);
327 :
328 0 : ret = btrfs_del_item(trans, root, path);
329 0 : out:
330 0 : btrfs_free_path(path);
331 0 : return ret;
332 : }
333 :
334 0 : int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
335 : u64 ref_id, u64 dirid, u64 *sequence,
336 : const struct fscrypt_str *name)
337 : {
338 0 : struct btrfs_root *tree_root = trans->fs_info->tree_root;
339 0 : struct btrfs_path *path;
340 0 : struct btrfs_root_ref *ref;
341 0 : struct extent_buffer *leaf;
342 0 : struct btrfs_key key;
343 0 : unsigned long ptr;
344 0 : int ret;
345 :
346 0 : path = btrfs_alloc_path();
347 0 : if (!path)
348 : return -ENOMEM;
349 :
350 0 : key.objectid = root_id;
351 0 : key.type = BTRFS_ROOT_BACKREF_KEY;
352 0 : key.offset = ref_id;
353 0 : again:
354 0 : ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
355 0 : if (ret < 0) {
356 0 : goto out;
357 0 : } else if (ret == 0) {
358 0 : leaf = path->nodes[0];
359 0 : ref = btrfs_item_ptr(leaf, path->slots[0],
360 : struct btrfs_root_ref);
361 0 : ptr = (unsigned long)(ref + 1);
362 0 : if ((btrfs_root_ref_dirid(leaf, ref) != dirid) ||
363 0 : (btrfs_root_ref_name_len(leaf, ref) != name->len) ||
364 0 : memcmp_extent_buffer(leaf, name->name, ptr, name->len)) {
365 0 : ret = -ENOENT;
366 0 : goto out;
367 : }
368 0 : *sequence = btrfs_root_ref_sequence(leaf, ref);
369 :
370 0 : ret = btrfs_del_item(trans, tree_root, path);
371 0 : if (ret)
372 0 : goto out;
373 : } else {
374 0 : ret = -ENOENT;
375 0 : goto out;
376 : }
377 :
378 0 : if (key.type == BTRFS_ROOT_BACKREF_KEY) {
379 0 : btrfs_release_path(path);
380 0 : key.objectid = ref_id;
381 0 : key.type = BTRFS_ROOT_REF_KEY;
382 0 : key.offset = root_id;
383 0 : goto again;
384 : }
385 :
386 0 : out:
387 0 : btrfs_free_path(path);
388 0 : return ret;
389 : }
390 :
391 : /*
392 : * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
393 : * or BTRFS_ROOT_BACKREF_KEY.
394 : *
395 : * The dirid, sequence, name and name_len refer to the directory entry
396 : * that is referencing the root.
397 : *
398 : * For a forward ref, the root_id is the id of the tree referencing
399 : * the root and ref_id is the id of the subvol or snapshot.
400 : *
401 : * For a back ref the root_id is the id of the subvol or snapshot and
402 : * ref_id is the id of the tree referencing it.
403 : *
404 : * Will return 0, -ENOMEM, or anything from the CoW path
405 : */
406 0 : int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
407 : u64 ref_id, u64 dirid, u64 sequence,
408 : const struct fscrypt_str *name)
409 : {
410 0 : struct btrfs_root *tree_root = trans->fs_info->tree_root;
411 0 : struct btrfs_key key;
412 0 : int ret;
413 0 : struct btrfs_path *path;
414 0 : struct btrfs_root_ref *ref;
415 0 : struct extent_buffer *leaf;
416 0 : unsigned long ptr;
417 :
418 0 : path = btrfs_alloc_path();
419 0 : if (!path)
420 : return -ENOMEM;
421 :
422 0 : key.objectid = root_id;
423 0 : key.type = BTRFS_ROOT_BACKREF_KEY;
424 0 : key.offset = ref_id;
425 0 : again:
426 0 : ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
427 0 : sizeof(*ref) + name->len);
428 0 : if (ret) {
429 0 : btrfs_abort_transaction(trans, ret);
430 0 : btrfs_free_path(path);
431 0 : return ret;
432 : }
433 :
434 0 : leaf = path->nodes[0];
435 0 : ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
436 0 : btrfs_set_root_ref_dirid(leaf, ref, dirid);
437 0 : btrfs_set_root_ref_sequence(leaf, ref, sequence);
438 0 : btrfs_set_root_ref_name_len(leaf, ref, name->len);
439 0 : ptr = (unsigned long)(ref + 1);
440 0 : write_extent_buffer(leaf, name->name, ptr, name->len);
441 0 : btrfs_mark_buffer_dirty(leaf);
442 :
443 0 : if (key.type == BTRFS_ROOT_BACKREF_KEY) {
444 0 : btrfs_release_path(path);
445 0 : key.objectid = ref_id;
446 0 : key.type = BTRFS_ROOT_REF_KEY;
447 0 : key.offset = root_id;
448 0 : goto again;
449 : }
450 :
451 0 : btrfs_free_path(path);
452 0 : return 0;
453 : }
454 :
455 : /*
456 : * Old btrfs forgets to init root_item->flags and root_item->byte_limit
457 : * for subvolumes. To work around this problem, we steal a bit from
458 : * root_item->inode_item->flags, and use it to indicate if those fields
459 : * have been properly initialized.
460 : */
461 0 : void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
462 : {
463 0 : u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
464 :
465 0 : if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
466 0 : inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
467 0 : btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
468 0 : btrfs_set_root_flags(root_item, 0);
469 0 : btrfs_set_root_limit(root_item, 0);
470 : }
471 0 : }
472 :
473 0 : void btrfs_update_root_times(struct btrfs_trans_handle *trans,
474 : struct btrfs_root *root)
475 : {
476 0 : struct btrfs_root_item *item = &root->root_item;
477 0 : struct timespec64 ct;
478 :
479 0 : ktime_get_real_ts64(&ct);
480 0 : spin_lock(&root->root_item_lock);
481 0 : btrfs_set_root_ctransid(item, trans->transid);
482 0 : btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
483 0 : btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
484 0 : spin_unlock(&root->root_item_lock);
485 0 : }
486 :
487 : /*
488 : * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
489 : * root: the root of the parent directory
490 : * rsv: block reservation
491 : * items: the number of items that we need do reservation
492 : * use_global_rsv: allow fallback to the global block reservation
493 : *
494 : * This function is used to reserve the space for snapshot/subvolume
495 : * creation and deletion. Those operations are different with the
496 : * common file/directory operations, they change two fs/file trees
497 : * and root tree, the number of items that the qgroup reserves is
498 : * different with the free space reservation. So we can not use
499 : * the space reservation mechanism in start_transaction().
500 : */
501 0 : int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
502 : struct btrfs_block_rsv *rsv, int items,
503 : bool use_global_rsv)
504 : {
505 0 : u64 qgroup_num_bytes = 0;
506 0 : u64 num_bytes;
507 0 : int ret;
508 0 : struct btrfs_fs_info *fs_info = root->fs_info;
509 0 : struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
510 :
511 0 : if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
512 : /* One for parent inode, two for dir entries */
513 0 : qgroup_num_bytes = 3 * fs_info->nodesize;
514 0 : ret = btrfs_qgroup_reserve_meta_prealloc(root,
515 : qgroup_num_bytes, true,
516 : false);
517 0 : if (ret)
518 : return ret;
519 : }
520 :
521 0 : num_bytes = btrfs_calc_insert_metadata_size(fs_info, items);
522 0 : rsv->space_info = btrfs_find_space_info(fs_info,
523 : BTRFS_BLOCK_GROUP_METADATA);
524 0 : ret = btrfs_block_rsv_add(fs_info, rsv, num_bytes,
525 : BTRFS_RESERVE_FLUSH_ALL);
526 :
527 0 : if (ret == -ENOSPC && use_global_rsv)
528 0 : ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true);
529 :
530 0 : if (ret && qgroup_num_bytes)
531 0 : btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
532 :
533 0 : if (!ret) {
534 0 : spin_lock(&rsv->lock);
535 0 : rsv->qgroup_rsv_reserved += qgroup_num_bytes;
536 0 : spin_unlock(&rsv->lock);
537 : }
538 : return ret;
539 : }
540 :
541 0 : void btrfs_subvolume_release_metadata(struct btrfs_root *root,
542 : struct btrfs_block_rsv *rsv)
543 : {
544 0 : struct btrfs_fs_info *fs_info = root->fs_info;
545 0 : u64 qgroup_to_release;
546 :
547 0 : btrfs_block_rsv_release(fs_info, rsv, (u64)-1, &qgroup_to_release);
548 0 : btrfs_qgroup_convert_reserved_meta(root, qgroup_to_release);
549 0 : }
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