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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 */
27static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
28 struct btrfs_root_item *item)
29{
30 u32 len;
31 int need_reset = 0;
32
33 len = btrfs_item_size(eb, slot);
34 read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
35 min_t(u32, len, sizeof(*item)));
36 if (len < sizeof(*item))
37 need_reset = 1;
38 if (!need_reset && btrfs_root_generation(item)
39 != btrfs_root_generation_v2(item)) {
40 if (btrfs_root_generation_v2(item) != 0) {
41 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 if (need_reset) {
47 /* Clear all members from generation_v2 onwards. */
48 memset_startat(item, 0, generation_v2);
49 generate_random_guid(item->uuid);
50 }
51}
52
53/*
54 * Lookup the root by the key.
55 *
56 * root: the root of the root tree
57 * search_key: the key to search
58 * path: the path we search
59 * root_item: the root item of the tree we look for
60 * root_key: the root key of the tree we look for
61 *
62 * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset
63 * of the search key, just lookup the root with the highest offset for a
64 * given objectid.
65 *
66 * If we find something return 0, otherwise > 0, < 0 on error.
67 */
68int btrfs_find_root(struct btrfs_root *root, const struct btrfs_key *search_key,
69 struct btrfs_path *path, struct btrfs_root_item *root_item,
70 struct btrfs_key *root_key)
71{
72 struct btrfs_key found_key;
73 struct extent_buffer *l;
74 int ret;
75 int slot;
76
77 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
78 if (ret < 0)
79 return ret;
80
81 if (search_key->offset != -1ULL) { /* the search key is exact */
82 if (ret > 0)
83 goto out;
84 } else {
85 BUG_ON(ret == 0); /* Logical error */
86 if (path->slots[0] == 0)
87 goto out;
88 path->slots[0]--;
89 ret = 0;
90 }
91
92 l = path->nodes[0];
93 slot = path->slots[0];
94
95 btrfs_item_key_to_cpu(l, &found_key, slot);
96 if (found_key.objectid != search_key->objectid ||
97 found_key.type != BTRFS_ROOT_ITEM_KEY) {
98 ret = 1;
99 goto out;
100 }
101
102 if (root_item)
103 btrfs_read_root_item(l, slot, root_item);
104 if (root_key)
105 memcpy(root_key, &found_key, sizeof(found_key));
106out:
107 btrfs_release_path(path);
108 return ret;
109}
110
111void btrfs_set_root_node(struct btrfs_root_item *item,
112 struct extent_buffer *node)
113{
114 btrfs_set_root_bytenr(item, node->start);
115 btrfs_set_root_level(item, btrfs_header_level(node));
116 btrfs_set_root_generation(item, btrfs_header_generation(node));
117}
118
119/*
120 * copy the data in 'item' into the btree
121 */
122int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
123 *root, struct btrfs_key *key, struct btrfs_root_item
124 *item)
125{
126 struct btrfs_fs_info *fs_info = root->fs_info;
127 struct btrfs_path *path;
128 struct extent_buffer *l;
129 int ret;
130 int slot;
131 unsigned long ptr;
132 u32 old_len;
133
134 path = btrfs_alloc_path();
135 if (!path)
136 return -ENOMEM;
137
138 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
139 if (ret < 0)
140 goto out;
141
142 if (ret > 0) {
143 btrfs_crit(fs_info,
144 "unable to find root key (%llu %u %llu) in tree %llu",
145 key->objectid, key->type, key->offset,
146 root->root_key.objectid);
147 ret = -EUCLEAN;
148 btrfs_abort_transaction(trans, ret);
149 goto out;
150 }
151
152 l = path->nodes[0];
153 slot = path->slots[0];
154 ptr = btrfs_item_ptr_offset(l, slot);
155 old_len = btrfs_item_size(l, slot);
156
157 /*
158 * If this is the first time we update the root item which originated
159 * from an older kernel, we need to enlarge the item size to make room
160 * for the added fields.
161 */
162 if (old_len < sizeof(*item)) {
163 btrfs_release_path(path);
164 ret = btrfs_search_slot(trans, root, key, path,
165 -1, 1);
166 if (ret < 0) {
167 btrfs_abort_transaction(trans, ret);
168 goto out;
169 }
170
171 ret = btrfs_del_item(trans, root, path);
172 if (ret < 0) {
173 btrfs_abort_transaction(trans, ret);
174 goto out;
175 }
176 btrfs_release_path(path);
177 ret = btrfs_insert_empty_item(trans, root, path,
178 key, sizeof(*item));
179 if (ret < 0) {
180 btrfs_abort_transaction(trans, ret);
181 goto out;
182 }
183 l = path->nodes[0];
184 slot = path->slots[0];
185 ptr = btrfs_item_ptr_offset(l, slot);
186 }
187
188 /*
189 * Update generation_v2 so at the next mount we know the new root
190 * fields are valid.
191 */
192 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
193
194 write_extent_buffer(l, item, ptr, sizeof(*item));
195 btrfs_mark_buffer_dirty(trans, path->nodes[0]);
196out:
197 btrfs_free_path(path);
198 return ret;
199}
200
201int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
202 const struct btrfs_key *key, struct btrfs_root_item *item)
203{
204 /*
205 * Make sure generation v1 and v2 match. See update_root for details.
206 */
207 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
208 return btrfs_insert_item(trans, root, key, item, sizeof(*item));
209}
210
211int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
212{
213 struct btrfs_root *tree_root = fs_info->tree_root;
214 struct extent_buffer *leaf;
215 struct btrfs_path *path;
216 struct btrfs_key key;
217 struct btrfs_root *root;
218 int err = 0;
219 int ret;
220
221 path = btrfs_alloc_path();
222 if (!path)
223 return -ENOMEM;
224
225 key.objectid = BTRFS_ORPHAN_OBJECTID;
226 key.type = BTRFS_ORPHAN_ITEM_KEY;
227 key.offset = 0;
228
229 while (1) {
230 u64 root_objectid;
231
232 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
233 if (ret < 0) {
234 err = ret;
235 break;
236 }
237
238 leaf = path->nodes[0];
239 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
240 ret = btrfs_next_leaf(tree_root, path);
241 if (ret < 0)
242 err = ret;
243 if (ret != 0)
244 break;
245 leaf = path->nodes[0];
246 }
247
248 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
249 btrfs_release_path(path);
250
251 if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
252 key.type != BTRFS_ORPHAN_ITEM_KEY)
253 break;
254
255 root_objectid = key.offset;
256 key.offset++;
257
258 root = btrfs_get_fs_root(fs_info, root_objectid, false);
259 err = PTR_ERR_OR_ZERO(root);
260 if (err && err != -ENOENT) {
261 break;
262 } else if (err == -ENOENT) {
263 struct btrfs_trans_handle *trans;
264
265 btrfs_release_path(path);
266
267 trans = btrfs_join_transaction(tree_root);
268 if (IS_ERR(trans)) {
269 err = PTR_ERR(trans);
270 btrfs_handle_fs_error(fs_info, err,
271 "Failed to start trans to delete orphan item");
272 break;
273 }
274 err = btrfs_del_orphan_item(trans, tree_root,
275 root_objectid);
276 btrfs_end_transaction(trans);
277 if (err) {
278 btrfs_handle_fs_error(fs_info, err,
279 "Failed to delete root orphan item");
280 break;
281 }
282 continue;
283 }
284
285 WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state));
286 if (btrfs_root_refs(&root->root_item) == 0) {
287 struct btrfs_key drop_key;
288
289 btrfs_disk_key_to_cpu(&drop_key, &root->root_item.drop_progress);
290 /*
291 * If we have a non-zero drop_progress then we know we
292 * made it partly through deleting this snapshot, and
293 * thus we need to make sure we block any balance from
294 * happening until this snapshot is completely dropped.
295 */
296 if (drop_key.objectid != 0 || drop_key.type != 0 ||
297 drop_key.offset != 0) {
298 set_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);
299 set_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);
300 }
301
302 set_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
303 btrfs_add_dead_root(root);
304 }
305 btrfs_put_root(root);
306 }
307
308 btrfs_free_path(path);
309 return err;
310}
311
312/* drop the root item for 'key' from the tree root */
313int btrfs_del_root(struct btrfs_trans_handle *trans,
314 const struct btrfs_key *key)
315{
316 struct btrfs_root *root = trans->fs_info->tree_root;
317 struct btrfs_path *path;
318 int ret;
319
320 path = btrfs_alloc_path();
321 if (!path)
322 return -ENOMEM;
323 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
324 if (ret < 0)
325 goto out;
326
327 BUG_ON(ret != 0);
328
329 ret = btrfs_del_item(trans, root, path);
330out:
331 btrfs_free_path(path);
332 return ret;
333}
334
335int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
336 u64 ref_id, u64 dirid, u64 *sequence,
337 const struct fscrypt_str *name)
338{
339 struct btrfs_root *tree_root = trans->fs_info->tree_root;
340 struct btrfs_path *path;
341 struct btrfs_root_ref *ref;
342 struct extent_buffer *leaf;
343 struct btrfs_key key;
344 unsigned long ptr;
345 int ret;
346
347 path = btrfs_alloc_path();
348 if (!path)
349 return -ENOMEM;
350
351 key.objectid = root_id;
352 key.type = BTRFS_ROOT_BACKREF_KEY;
353 key.offset = ref_id;
354again:
355 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
356 if (ret < 0) {
357 goto out;
358 } else if (ret == 0) {
359 leaf = path->nodes[0];
360 ref = btrfs_item_ptr(leaf, path->slots[0],
361 struct btrfs_root_ref);
362 ptr = (unsigned long)(ref + 1);
363 if ((btrfs_root_ref_dirid(leaf, ref) != dirid) ||
364 (btrfs_root_ref_name_len(leaf, ref) != name->len) ||
365 memcmp_extent_buffer(leaf, name->name, ptr, name->len)) {
366 ret = -ENOENT;
367 goto out;
368 }
369 *sequence = btrfs_root_ref_sequence(leaf, ref);
370
371 ret = btrfs_del_item(trans, tree_root, path);
372 if (ret)
373 goto out;
374 } else {
375 ret = -ENOENT;
376 goto out;
377 }
378
379 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
380 btrfs_release_path(path);
381 key.objectid = ref_id;
382 key.type = BTRFS_ROOT_REF_KEY;
383 key.offset = root_id;
384 goto again;
385 }
386
387out:
388 btrfs_free_path(path);
389 return ret;
390}
391
392/*
393 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
394 * or BTRFS_ROOT_BACKREF_KEY.
395 *
396 * The dirid, sequence, name and name_len refer to the directory entry
397 * that is referencing the root.
398 *
399 * For a forward ref, the root_id is the id of the tree referencing
400 * the root and ref_id is the id of the subvol or snapshot.
401 *
402 * For a back ref the root_id is the id of the subvol or snapshot and
403 * ref_id is the id of the tree referencing it.
404 *
405 * Will return 0, -ENOMEM, or anything from the CoW path
406 */
407int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
408 u64 ref_id, u64 dirid, u64 sequence,
409 const struct fscrypt_str *name)
410{
411 struct btrfs_root *tree_root = trans->fs_info->tree_root;
412 struct btrfs_key key;
413 int ret;
414 struct btrfs_path *path;
415 struct btrfs_root_ref *ref;
416 struct extent_buffer *leaf;
417 unsigned long ptr;
418
419 path = btrfs_alloc_path();
420 if (!path)
421 return -ENOMEM;
422
423 key.objectid = root_id;
424 key.type = BTRFS_ROOT_BACKREF_KEY;
425 key.offset = ref_id;
426again:
427 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
428 sizeof(*ref) + name->len);
429 if (ret) {
430 btrfs_abort_transaction(trans, ret);
431 btrfs_free_path(path);
432 return ret;
433 }
434
435 leaf = path->nodes[0];
436 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
437 btrfs_set_root_ref_dirid(leaf, ref, dirid);
438 btrfs_set_root_ref_sequence(leaf, ref, sequence);
439 btrfs_set_root_ref_name_len(leaf, ref, name->len);
440 ptr = (unsigned long)(ref + 1);
441 write_extent_buffer(leaf, name->name, ptr, name->len);
442 btrfs_mark_buffer_dirty(trans, leaf);
443
444 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
445 btrfs_release_path(path);
446 key.objectid = ref_id;
447 key.type = BTRFS_ROOT_REF_KEY;
448 key.offset = root_id;
449 goto again;
450 }
451
452 btrfs_free_path(path);
453 return 0;
454}
455
456/*
457 * Old btrfs forgets to init root_item->flags and root_item->byte_limit
458 * for subvolumes. To work around this problem, we steal a bit from
459 * root_item->inode_item->flags, and use it to indicate if those fields
460 * have been properly initialized.
461 */
462void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
463{
464 u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
465
466 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
467 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
468 btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
469 btrfs_set_root_flags(root_item, 0);
470 btrfs_set_root_limit(root_item, 0);
471 }
472}
473
474void btrfs_update_root_times(struct btrfs_trans_handle *trans,
475 struct btrfs_root *root)
476{
477 struct btrfs_root_item *item = &root->root_item;
478 struct timespec64 ct;
479
480 ktime_get_real_ts64(&ct);
481 spin_lock(&root->root_item_lock);
482 btrfs_set_root_ctransid(item, trans->transid);
483 btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
484 btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
485 spin_unlock(&root->root_item_lock);
486}
487
488/*
489 * Reserve space for subvolume operation.
490 *
491 * root: the root of the parent directory
492 * rsv: block reservation
493 * items: the number of items that we need do reservation
494 * use_global_rsv: allow fallback to the global block reservation
495 *
496 * This function is used to reserve the space for snapshot/subvolume
497 * creation and deletion. Those operations are different with the
498 * common file/directory operations, they change two fs/file trees
499 * and root tree, the number of items that the qgroup reserves is
500 * different with the free space reservation. So we can not use
501 * the space reservation mechanism in start_transaction().
502 */
503int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
504 struct btrfs_block_rsv *rsv, int items,
505 bool use_global_rsv)
506{
507 u64 qgroup_num_bytes = 0;
508 u64 num_bytes;
509 int ret;
510 struct btrfs_fs_info *fs_info = root->fs_info;
511 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
512
513 if (btrfs_qgroup_enabled(fs_info)) {
514 /* One for parent inode, two for dir entries */
515 qgroup_num_bytes = 3 * fs_info->nodesize;
516 ret = btrfs_qgroup_reserve_meta_prealloc(root,
517 qgroup_num_bytes, true,
518 false);
519 if (ret)
520 return ret;
521 }
522
523 num_bytes = btrfs_calc_insert_metadata_size(fs_info, items);
524 rsv->space_info = btrfs_find_space_info(fs_info,
525 BTRFS_BLOCK_GROUP_METADATA);
526 ret = btrfs_block_rsv_add(fs_info, rsv, num_bytes,
527 BTRFS_RESERVE_FLUSH_ALL);
528
529 if (ret == -ENOSPC && use_global_rsv)
530 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true);
531
532 if (ret && qgroup_num_bytes)
533 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
534
535 if (!ret) {
536 spin_lock(&rsv->lock);
537 rsv->qgroup_rsv_reserved += qgroup_num_bytes;
538 spin_unlock(&rsv->lock);
539 }
540 return ret;
541}
542
543void btrfs_subvolume_release_metadata(struct btrfs_root *root,
544 struct btrfs_block_rsv *rsv)
545{
546 struct btrfs_fs_info *fs_info = root->fs_info;
547 u64 qgroup_to_release;
548
549 btrfs_block_rsv_release(fs_info, rsv, (u64)-1, &qgroup_to_release);
550 btrfs_qgroup_convert_reserved_meta(root, qgroup_to_release);
551}
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 "transaction.h"
10#include "disk-io.h"
11#include "print-tree.h"
12#include "qgroup.h"
13#include "space-info.h"
14
15/*
16 * Read a root item from the tree. In case we detect a root item smaller then
17 * sizeof(root_item), we know it's an old version of the root structure and
18 * initialize all new fields to zero. The same happens if we detect mismatching
19 * generation numbers as then we know the root was once mounted with an older
20 * kernel that was not aware of the root item structure change.
21 */
22static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
23 struct btrfs_root_item *item)
24{
25 u32 len;
26 int need_reset = 0;
27
28 len = btrfs_item_size_nr(eb, slot);
29 read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
30 min_t(u32, len, sizeof(*item)));
31 if (len < sizeof(*item))
32 need_reset = 1;
33 if (!need_reset && btrfs_root_generation(item)
34 != btrfs_root_generation_v2(item)) {
35 if (btrfs_root_generation_v2(item) != 0) {
36 btrfs_warn(eb->fs_info,
37 "mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.");
38 }
39 need_reset = 1;
40 }
41 if (need_reset) {
42 memset(&item->generation_v2, 0,
43 sizeof(*item) - offsetof(struct btrfs_root_item,
44 generation_v2));
45
46 generate_random_guid(item->uuid);
47 }
48}
49
50/*
51 * btrfs_find_root - lookup the root by the key.
52 * root: the root of the root tree
53 * search_key: the key to search
54 * path: the path we search
55 * root_item: the root item of the tree we look for
56 * root_key: the root key of the tree we look for
57 *
58 * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset
59 * of the search key, just lookup the root with the highest offset for a
60 * given objectid.
61 *
62 * If we find something return 0, otherwise > 0, < 0 on error.
63 */
64int btrfs_find_root(struct btrfs_root *root, const struct btrfs_key *search_key,
65 struct btrfs_path *path, struct btrfs_root_item *root_item,
66 struct btrfs_key *root_key)
67{
68 struct btrfs_key found_key;
69 struct extent_buffer *l;
70 int ret;
71 int slot;
72
73 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
74 if (ret < 0)
75 return ret;
76
77 if (search_key->offset != -1ULL) { /* the search key is exact */
78 if (ret > 0)
79 goto out;
80 } else {
81 BUG_ON(ret == 0); /* Logical error */
82 if (path->slots[0] == 0)
83 goto out;
84 path->slots[0]--;
85 ret = 0;
86 }
87
88 l = path->nodes[0];
89 slot = path->slots[0];
90
91 btrfs_item_key_to_cpu(l, &found_key, slot);
92 if (found_key.objectid != search_key->objectid ||
93 found_key.type != BTRFS_ROOT_ITEM_KEY) {
94 ret = 1;
95 goto out;
96 }
97
98 if (root_item)
99 btrfs_read_root_item(l, slot, root_item);
100 if (root_key)
101 memcpy(root_key, &found_key, sizeof(found_key));
102out:
103 btrfs_release_path(path);
104 return ret;
105}
106
107void btrfs_set_root_node(struct btrfs_root_item *item,
108 struct extent_buffer *node)
109{
110 btrfs_set_root_bytenr(item, node->start);
111 btrfs_set_root_level(item, btrfs_header_level(node));
112 btrfs_set_root_generation(item, btrfs_header_generation(node));
113}
114
115/*
116 * copy the data in 'item' into the btree
117 */
118int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
119 *root, struct btrfs_key *key, struct btrfs_root_item
120 *item)
121{
122 struct btrfs_fs_info *fs_info = root->fs_info;
123 struct btrfs_path *path;
124 struct extent_buffer *l;
125 int ret;
126 int slot;
127 unsigned long ptr;
128 u32 old_len;
129
130 path = btrfs_alloc_path();
131 if (!path)
132 return -ENOMEM;
133
134 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
135 if (ret < 0)
136 goto out;
137
138 if (ret > 0) {
139 btrfs_crit(fs_info,
140 "unable to find root key (%llu %u %llu) in tree %llu",
141 key->objectid, key->type, key->offset,
142 root->root_key.objectid);
143 ret = -EUCLEAN;
144 btrfs_abort_transaction(trans, ret);
145 goto out;
146 }
147
148 l = path->nodes[0];
149 slot = path->slots[0];
150 ptr = btrfs_item_ptr_offset(l, slot);
151 old_len = btrfs_item_size_nr(l, slot);
152
153 /*
154 * If this is the first time we update the root item which originated
155 * from an older kernel, we need to enlarge the item size to make room
156 * for the added fields.
157 */
158 if (old_len < sizeof(*item)) {
159 btrfs_release_path(path);
160 ret = btrfs_search_slot(trans, root, key, path,
161 -1, 1);
162 if (ret < 0) {
163 btrfs_abort_transaction(trans, ret);
164 goto out;
165 }
166
167 ret = btrfs_del_item(trans, root, path);
168 if (ret < 0) {
169 btrfs_abort_transaction(trans, ret);
170 goto out;
171 }
172 btrfs_release_path(path);
173 ret = btrfs_insert_empty_item(trans, root, path,
174 key, sizeof(*item));
175 if (ret < 0) {
176 btrfs_abort_transaction(trans, ret);
177 goto out;
178 }
179 l = path->nodes[0];
180 slot = path->slots[0];
181 ptr = btrfs_item_ptr_offset(l, slot);
182 }
183
184 /*
185 * Update generation_v2 so at the next mount we know the new root
186 * fields are valid.
187 */
188 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
189
190 write_extent_buffer(l, item, ptr, sizeof(*item));
191 btrfs_mark_buffer_dirty(path->nodes[0]);
192out:
193 btrfs_free_path(path);
194 return ret;
195}
196
197int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
198 const struct btrfs_key *key, struct btrfs_root_item *item)
199{
200 /*
201 * Make sure generation v1 and v2 match. See update_root for details.
202 */
203 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
204 return btrfs_insert_item(trans, root, key, item, sizeof(*item));
205}
206
207int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
208{
209 struct btrfs_root *tree_root = fs_info->tree_root;
210 struct extent_buffer *leaf;
211 struct btrfs_path *path;
212 struct btrfs_key key;
213 struct btrfs_root *root;
214 int err = 0;
215 int ret;
216
217 path = btrfs_alloc_path();
218 if (!path)
219 return -ENOMEM;
220
221 key.objectid = BTRFS_ORPHAN_OBJECTID;
222 key.type = BTRFS_ORPHAN_ITEM_KEY;
223 key.offset = 0;
224
225 while (1) {
226 u64 root_objectid;
227
228 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
229 if (ret < 0) {
230 err = ret;
231 break;
232 }
233
234 leaf = path->nodes[0];
235 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
236 ret = btrfs_next_leaf(tree_root, path);
237 if (ret < 0)
238 err = ret;
239 if (ret != 0)
240 break;
241 leaf = path->nodes[0];
242 }
243
244 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
245 btrfs_release_path(path);
246
247 if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
248 key.type != BTRFS_ORPHAN_ITEM_KEY)
249 break;
250
251 root_objectid = key.offset;
252 key.offset++;
253
254 root = btrfs_get_fs_root(fs_info, root_objectid, false);
255 err = PTR_ERR_OR_ZERO(root);
256 if (err && err != -ENOENT) {
257 break;
258 } else if (err == -ENOENT) {
259 struct btrfs_trans_handle *trans;
260
261 btrfs_release_path(path);
262
263 trans = btrfs_join_transaction(tree_root);
264 if (IS_ERR(trans)) {
265 err = PTR_ERR(trans);
266 btrfs_handle_fs_error(fs_info, err,
267 "Failed to start trans to delete orphan item");
268 break;
269 }
270 err = btrfs_del_orphan_item(trans, tree_root,
271 root_objectid);
272 btrfs_end_transaction(trans);
273 if (err) {
274 btrfs_handle_fs_error(fs_info, err,
275 "Failed to delete root orphan item");
276 break;
277 }
278 continue;
279 }
280
281 WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state));
282 if (btrfs_root_refs(&root->root_item) == 0) {
283 set_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
284 btrfs_add_dead_root(root);
285 }
286 btrfs_put_root(root);
287 }
288
289 btrfs_free_path(path);
290 return err;
291}
292
293/* drop the root item for 'key' from the tree root */
294int btrfs_del_root(struct btrfs_trans_handle *trans,
295 const struct btrfs_key *key)
296{
297 struct btrfs_root *root = trans->fs_info->tree_root;
298 struct btrfs_path *path;
299 int ret;
300
301 path = btrfs_alloc_path();
302 if (!path)
303 return -ENOMEM;
304 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
305 if (ret < 0)
306 goto out;
307
308 BUG_ON(ret != 0);
309
310 ret = btrfs_del_item(trans, root, path);
311out:
312 btrfs_free_path(path);
313 return ret;
314}
315
316int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
317 u64 ref_id, u64 dirid, u64 *sequence, const char *name,
318 int name_len)
319
320{
321 struct btrfs_root *tree_root = trans->fs_info->tree_root;
322 struct btrfs_path *path;
323 struct btrfs_root_ref *ref;
324 struct extent_buffer *leaf;
325 struct btrfs_key key;
326 unsigned long ptr;
327 int err = 0;
328 int ret;
329
330 path = btrfs_alloc_path();
331 if (!path)
332 return -ENOMEM;
333
334 key.objectid = root_id;
335 key.type = BTRFS_ROOT_BACKREF_KEY;
336 key.offset = ref_id;
337again:
338 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
339 BUG_ON(ret < 0);
340 if (ret == 0) {
341 leaf = path->nodes[0];
342 ref = btrfs_item_ptr(leaf, path->slots[0],
343 struct btrfs_root_ref);
344 ptr = (unsigned long)(ref + 1);
345 if ((btrfs_root_ref_dirid(leaf, ref) != dirid) ||
346 (btrfs_root_ref_name_len(leaf, ref) != name_len) ||
347 memcmp_extent_buffer(leaf, name, ptr, name_len)) {
348 err = -ENOENT;
349 goto out;
350 }
351 *sequence = btrfs_root_ref_sequence(leaf, ref);
352
353 ret = btrfs_del_item(trans, tree_root, path);
354 if (ret) {
355 err = ret;
356 goto out;
357 }
358 } else
359 err = -ENOENT;
360
361 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
362 btrfs_release_path(path);
363 key.objectid = ref_id;
364 key.type = BTRFS_ROOT_REF_KEY;
365 key.offset = root_id;
366 goto again;
367 }
368
369out:
370 btrfs_free_path(path);
371 return err;
372}
373
374/*
375 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
376 * or BTRFS_ROOT_BACKREF_KEY.
377 *
378 * The dirid, sequence, name and name_len refer to the directory entry
379 * that is referencing the root.
380 *
381 * For a forward ref, the root_id is the id of the tree referencing
382 * the root and ref_id is the id of the subvol or snapshot.
383 *
384 * For a back ref the root_id is the id of the subvol or snapshot and
385 * ref_id is the id of the tree referencing it.
386 *
387 * Will return 0, -ENOMEM, or anything from the CoW path
388 */
389int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
390 u64 ref_id, u64 dirid, u64 sequence, const char *name,
391 int name_len)
392{
393 struct btrfs_root *tree_root = trans->fs_info->tree_root;
394 struct btrfs_key key;
395 int ret;
396 struct btrfs_path *path;
397 struct btrfs_root_ref *ref;
398 struct extent_buffer *leaf;
399 unsigned long ptr;
400
401 path = btrfs_alloc_path();
402 if (!path)
403 return -ENOMEM;
404
405 key.objectid = root_id;
406 key.type = BTRFS_ROOT_BACKREF_KEY;
407 key.offset = ref_id;
408again:
409 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
410 sizeof(*ref) + name_len);
411 if (ret) {
412 btrfs_abort_transaction(trans, ret);
413 btrfs_free_path(path);
414 return ret;
415 }
416
417 leaf = path->nodes[0];
418 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
419 btrfs_set_root_ref_dirid(leaf, ref, dirid);
420 btrfs_set_root_ref_sequence(leaf, ref, sequence);
421 btrfs_set_root_ref_name_len(leaf, ref, name_len);
422 ptr = (unsigned long)(ref + 1);
423 write_extent_buffer(leaf, name, ptr, name_len);
424 btrfs_mark_buffer_dirty(leaf);
425
426 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
427 btrfs_release_path(path);
428 key.objectid = ref_id;
429 key.type = BTRFS_ROOT_REF_KEY;
430 key.offset = root_id;
431 goto again;
432 }
433
434 btrfs_free_path(path);
435 return 0;
436}
437
438/*
439 * Old btrfs forgets to init root_item->flags and root_item->byte_limit
440 * for subvolumes. To work around this problem, we steal a bit from
441 * root_item->inode_item->flags, and use it to indicate if those fields
442 * have been properly initialized.
443 */
444void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
445{
446 u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
447
448 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
449 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
450 btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
451 btrfs_set_root_flags(root_item, 0);
452 btrfs_set_root_limit(root_item, 0);
453 }
454}
455
456void btrfs_update_root_times(struct btrfs_trans_handle *trans,
457 struct btrfs_root *root)
458{
459 struct btrfs_root_item *item = &root->root_item;
460 struct timespec64 ct;
461
462 ktime_get_real_ts64(&ct);
463 spin_lock(&root->root_item_lock);
464 btrfs_set_root_ctransid(item, trans->transid);
465 btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
466 btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
467 spin_unlock(&root->root_item_lock);
468}
469
470/*
471 * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
472 * root: the root of the parent directory
473 * rsv: block reservation
474 * items: the number of items that we need do reservation
475 * use_global_rsv: allow fallback to the global block reservation
476 *
477 * This function is used to reserve the space for snapshot/subvolume
478 * creation and deletion. Those operations are different with the
479 * common file/directory operations, they change two fs/file trees
480 * and root tree, the number of items that the qgroup reserves is
481 * different with the free space reservation. So we can not use
482 * the space reservation mechanism in start_transaction().
483 */
484int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
485 struct btrfs_block_rsv *rsv, int items,
486 bool use_global_rsv)
487{
488 u64 qgroup_num_bytes = 0;
489 u64 num_bytes;
490 int ret;
491 struct btrfs_fs_info *fs_info = root->fs_info;
492 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
493
494 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
495 /* One for parent inode, two for dir entries */
496 qgroup_num_bytes = 3 * fs_info->nodesize;
497 ret = btrfs_qgroup_reserve_meta_prealloc(root,
498 qgroup_num_bytes, true);
499 if (ret)
500 return ret;
501 }
502
503 num_bytes = btrfs_calc_insert_metadata_size(fs_info, items);
504 rsv->space_info = btrfs_find_space_info(fs_info,
505 BTRFS_BLOCK_GROUP_METADATA);
506 ret = btrfs_block_rsv_add(root, rsv, num_bytes,
507 BTRFS_RESERVE_FLUSH_ALL);
508
509 if (ret == -ENOSPC && use_global_rsv)
510 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true);
511
512 if (ret && qgroup_num_bytes)
513 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
514
515 return ret;
516}
517
518void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
519 struct btrfs_block_rsv *rsv)
520{
521 btrfs_block_rsv_release(fs_info, rsv, (u64)-1, NULL);
522}