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