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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 "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 uuid_le uuid;
26 u32 len;
27 int need_reset = 0;
28
29 len = btrfs_item_size_nr(eb, slot);
30 read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
31 min_t(u32, len, sizeof(*item)));
32 if (len < sizeof(*item))
33 need_reset = 1;
34 if (!need_reset && btrfs_root_generation(item)
35 != btrfs_root_generation_v2(item)) {
36 if (btrfs_root_generation_v2(item) != 0) {
37 btrfs_warn(eb->fs_info,
38 "mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.");
39 }
40 need_reset = 1;
41 }
42 if (need_reset) {
43 memset(&item->generation_v2, 0,
44 sizeof(*item) - offsetof(struct btrfs_root_item,
45 generation_v2));
46
47 uuid_le_gen(&uuid);
48 memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
49 }
50}
51
52/*
53 * btrfs_find_root - lookup the root by the key.
54 * root: the root of the root tree
55 * search_key: the key to search
56 * path: the path we search
57 * root_item: the root item of the tree we look for
58 * root_key: the root key of the tree we look for
59 *
60 * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset
61 * of the search key, just lookup the root with the highest offset for a
62 * given objectid.
63 *
64 * If we find something return 0, otherwise > 0, < 0 on error.
65 */
66int btrfs_find_root(struct btrfs_root *root, const struct btrfs_key *search_key,
67 struct btrfs_path *path, struct btrfs_root_item *root_item,
68 struct btrfs_key *root_key)
69{
70 struct btrfs_key found_key;
71 struct extent_buffer *l;
72 int ret;
73 int slot;
74
75 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
76 if (ret < 0)
77 return ret;
78
79 if (search_key->offset != -1ULL) { /* the search key is exact */
80 if (ret > 0)
81 goto out;
82 } else {
83 BUG_ON(ret == 0); /* Logical error */
84 if (path->slots[0] == 0)
85 goto out;
86 path->slots[0]--;
87 ret = 0;
88 }
89
90 l = path->nodes[0];
91 slot = path->slots[0];
92
93 btrfs_item_key_to_cpu(l, &found_key, slot);
94 if (found_key.objectid != search_key->objectid ||
95 found_key.type != BTRFS_ROOT_ITEM_KEY) {
96 ret = 1;
97 goto out;
98 }
99
100 if (root_item)
101 btrfs_read_root_item(l, slot, root_item);
102 if (root_key)
103 memcpy(root_key, &found_key, sizeof(found_key));
104out:
105 btrfs_release_path(path);
106 return ret;
107}
108
109void btrfs_set_root_node(struct btrfs_root_item *item,
110 struct extent_buffer *node)
111{
112 btrfs_set_root_bytenr(item, node->start);
113 btrfs_set_root_level(item, btrfs_header_level(node));
114 btrfs_set_root_generation(item, btrfs_header_generation(node));
115}
116
117/*
118 * copy the data in 'item' into the btree
119 */
120int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
121 *root, struct btrfs_key *key, struct btrfs_root_item
122 *item)
123{
124 struct btrfs_fs_info *fs_info = root->fs_info;
125 struct btrfs_path *path;
126 struct extent_buffer *l;
127 int ret;
128 int slot;
129 unsigned long ptr;
130 u32 old_len;
131
132 path = btrfs_alloc_path();
133 if (!path)
134 return -ENOMEM;
135
136 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
137 if (ret < 0)
138 goto out;
139
140 if (ret > 0) {
141 btrfs_crit(fs_info,
142 "unable to find root key (%llu %u %llu) in tree %llu",
143 key->objectid, key->type, key->offset,
144 root->root_key.objectid);
145 ret = -EUCLEAN;
146 btrfs_abort_transaction(trans, ret);
147 goto out;
148 }
149
150 l = path->nodes[0];
151 slot = path->slots[0];
152 ptr = btrfs_item_ptr_offset(l, slot);
153 old_len = btrfs_item_size_nr(l, slot);
154
155 /*
156 * If this is the first time we update the root item which originated
157 * from an older kernel, we need to enlarge the item size to make room
158 * for the added fields.
159 */
160 if (old_len < sizeof(*item)) {
161 btrfs_release_path(path);
162 ret = btrfs_search_slot(trans, root, key, path,
163 -1, 1);
164 if (ret < 0) {
165 btrfs_abort_transaction(trans, ret);
166 goto out;
167 }
168
169 ret = btrfs_del_item(trans, root, path);
170 if (ret < 0) {
171 btrfs_abort_transaction(trans, ret);
172 goto out;
173 }
174 btrfs_release_path(path);
175 ret = btrfs_insert_empty_item(trans, root, path,
176 key, sizeof(*item));
177 if (ret < 0) {
178 btrfs_abort_transaction(trans, ret);
179 goto out;
180 }
181 l = path->nodes[0];
182 slot = path->slots[0];
183 ptr = btrfs_item_ptr_offset(l, slot);
184 }
185
186 /*
187 * Update generation_v2 so at the next mount we know the new root
188 * fields are valid.
189 */
190 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
191
192 write_extent_buffer(l, item, ptr, sizeof(*item));
193 btrfs_mark_buffer_dirty(path->nodes[0]);
194out:
195 btrfs_free_path(path);
196 return ret;
197}
198
199int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
200 const struct btrfs_key *key, struct btrfs_root_item *item)
201{
202 /*
203 * Make sure generation v1 and v2 match. See update_root for details.
204 */
205 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
206 return btrfs_insert_item(trans, root, key, item, sizeof(*item));
207}
208
209int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
210{
211 struct btrfs_root *tree_root = fs_info->tree_root;
212 struct extent_buffer *leaf;
213 struct btrfs_path *path;
214 struct btrfs_key key;
215 struct btrfs_key root_key;
216 struct btrfs_root *root;
217 int err = 0;
218 int ret;
219
220 path = btrfs_alloc_path();
221 if (!path)
222 return -ENOMEM;
223
224 key.objectid = BTRFS_ORPHAN_OBJECTID;
225 key.type = BTRFS_ORPHAN_ITEM_KEY;
226 key.offset = 0;
227
228 root_key.type = BTRFS_ROOT_ITEM_KEY;
229 root_key.offset = (u64)-1;
230
231 while (1) {
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_key.objectid = key.offset;
256 key.offset++;
257
258 /*
259 * The root might have been inserted already, as before we look
260 * for orphan roots, log replay might have happened, which
261 * triggers a transaction commit and qgroup accounting, which
262 * in turn reads and inserts fs roots while doing backref
263 * walking.
264 */
265 root = btrfs_lookup_fs_root(fs_info, root_key.objectid);
266 if (root) {
267 WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
268 &root->state));
269 if (btrfs_root_refs(&root->root_item) == 0) {
270 set_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
271 btrfs_add_dead_root(root);
272 }
273 continue;
274 }
275
276 root = btrfs_read_fs_root(tree_root, &root_key);
277 err = PTR_ERR_OR_ZERO(root);
278 if (err && err != -ENOENT) {
279 break;
280 } else if (err == -ENOENT) {
281 struct btrfs_trans_handle *trans;
282
283 btrfs_release_path(path);
284
285 trans = btrfs_join_transaction(tree_root);
286 if (IS_ERR(trans)) {
287 err = PTR_ERR(trans);
288 btrfs_handle_fs_error(fs_info, err,
289 "Failed to start trans to delete orphan item");
290 break;
291 }
292 err = btrfs_del_orphan_item(trans, tree_root,
293 root_key.objectid);
294 btrfs_end_transaction(trans);
295 if (err) {
296 btrfs_handle_fs_error(fs_info, err,
297 "Failed to delete root orphan item");
298 break;
299 }
300 continue;
301 }
302
303 err = btrfs_init_fs_root(root);
304 if (err) {
305 btrfs_free_fs_root(root);
306 break;
307 }
308
309 set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
310
311 err = btrfs_insert_fs_root(fs_info, root);
312 if (err) {
313 BUG_ON(err == -EEXIST);
314 btrfs_free_fs_root(root);
315 break;
316 }
317
318 if (btrfs_root_refs(&root->root_item) == 0) {
319 set_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
320 btrfs_add_dead_root(root);
321 }
322 }
323
324 btrfs_free_path(path);
325 return err;
326}
327
328/* drop the root item for 'key' from the tree root */
329int btrfs_del_root(struct btrfs_trans_handle *trans,
330 const struct btrfs_key *key)
331{
332 struct btrfs_root *root = trans->fs_info->tree_root;
333 struct btrfs_path *path;
334 int ret;
335
336 path = btrfs_alloc_path();
337 if (!path)
338 return -ENOMEM;
339 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
340 if (ret < 0)
341 goto out;
342
343 BUG_ON(ret != 0);
344
345 ret = btrfs_del_item(trans, root, path);
346out:
347 btrfs_free_path(path);
348 return ret;
349}
350
351int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
352 u64 ref_id, u64 dirid, u64 *sequence, const char *name,
353 int name_len)
354
355{
356 struct btrfs_root *tree_root = trans->fs_info->tree_root;
357 struct btrfs_path *path;
358 struct btrfs_root_ref *ref;
359 struct extent_buffer *leaf;
360 struct btrfs_key key;
361 unsigned long ptr;
362 int err = 0;
363 int ret;
364
365 path = btrfs_alloc_path();
366 if (!path)
367 return -ENOMEM;
368
369 key.objectid = root_id;
370 key.type = BTRFS_ROOT_BACKREF_KEY;
371 key.offset = ref_id;
372again:
373 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
374 BUG_ON(ret < 0);
375 if (ret == 0) {
376 leaf = path->nodes[0];
377 ref = btrfs_item_ptr(leaf, path->slots[0],
378 struct btrfs_root_ref);
379
380 WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
381 WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
382 ptr = (unsigned long)(ref + 1);
383 WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
384 *sequence = btrfs_root_ref_sequence(leaf, ref);
385
386 ret = btrfs_del_item(trans, tree_root, path);
387 if (ret) {
388 err = ret;
389 goto out;
390 }
391 } else
392 err = -ENOENT;
393
394 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
395 btrfs_release_path(path);
396 key.objectid = ref_id;
397 key.type = BTRFS_ROOT_REF_KEY;
398 key.offset = root_id;
399 goto again;
400 }
401
402out:
403 btrfs_free_path(path);
404 return err;
405}
406
407/*
408 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
409 * or BTRFS_ROOT_BACKREF_KEY.
410 *
411 * The dirid, sequence, name and name_len refer to the directory entry
412 * that is referencing the root.
413 *
414 * For a forward ref, the root_id is the id of the tree referencing
415 * the root and ref_id is the id of the subvol or snapshot.
416 *
417 * For a back ref the root_id is the id of the subvol or snapshot and
418 * ref_id is the id of the tree referencing it.
419 *
420 * Will return 0, -ENOMEM, or anything from the CoW path
421 */
422int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
423 u64 ref_id, u64 dirid, u64 sequence, const char *name,
424 int name_len)
425{
426 struct btrfs_root *tree_root = trans->fs_info->tree_root;
427 struct btrfs_key key;
428 int ret;
429 struct btrfs_path *path;
430 struct btrfs_root_ref *ref;
431 struct extent_buffer *leaf;
432 unsigned long ptr;
433
434 path = btrfs_alloc_path();
435 if (!path)
436 return -ENOMEM;
437
438 key.objectid = root_id;
439 key.type = BTRFS_ROOT_BACKREF_KEY;
440 key.offset = ref_id;
441again:
442 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
443 sizeof(*ref) + name_len);
444 if (ret) {
445 btrfs_abort_transaction(trans, ret);
446 btrfs_free_path(path);
447 return ret;
448 }
449
450 leaf = path->nodes[0];
451 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
452 btrfs_set_root_ref_dirid(leaf, ref, dirid);
453 btrfs_set_root_ref_sequence(leaf, ref, sequence);
454 btrfs_set_root_ref_name_len(leaf, ref, name_len);
455 ptr = (unsigned long)(ref + 1);
456 write_extent_buffer(leaf, name, ptr, name_len);
457 btrfs_mark_buffer_dirty(leaf);
458
459 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
460 btrfs_release_path(path);
461 key.objectid = ref_id;
462 key.type = BTRFS_ROOT_REF_KEY;
463 key.offset = root_id;
464 goto again;
465 }
466
467 btrfs_free_path(path);
468 return 0;
469}
470
471/*
472 * Old btrfs forgets to init root_item->flags and root_item->byte_limit
473 * for subvolumes. To work around this problem, we steal a bit from
474 * root_item->inode_item->flags, and use it to indicate if those fields
475 * have been properly initialized.
476 */
477void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
478{
479 u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
480
481 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
482 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
483 btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
484 btrfs_set_root_flags(root_item, 0);
485 btrfs_set_root_limit(root_item, 0);
486 }
487}
488
489void btrfs_update_root_times(struct btrfs_trans_handle *trans,
490 struct btrfs_root *root)
491{
492 struct btrfs_root_item *item = &root->root_item;
493 struct timespec64 ct;
494
495 ktime_get_real_ts64(&ct);
496 spin_lock(&root->root_item_lock);
497 btrfs_set_root_ctransid(item, trans->transid);
498 btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
499 btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
500 spin_unlock(&root->root_item_lock);
501}
502
503/*
504 * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
505 * root: the root of the parent directory
506 * rsv: block reservation
507 * items: the number of items that we need do reservation
508 * use_global_rsv: allow fallback to the global block reservation
509 *
510 * This function is used to reserve the space for snapshot/subvolume
511 * creation and deletion. Those operations are different with the
512 * common file/directory operations, they change two fs/file trees
513 * and root tree, the number of items that the qgroup reserves is
514 * different with the free space reservation. So we can not use
515 * the space reservation mechanism in start_transaction().
516 */
517int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
518 struct btrfs_block_rsv *rsv, int items,
519 bool use_global_rsv)
520{
521 u64 qgroup_num_bytes = 0;
522 u64 num_bytes;
523 int ret;
524 struct btrfs_fs_info *fs_info = root->fs_info;
525 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
526
527 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
528 /* One for parent inode, two for dir entries */
529 qgroup_num_bytes = 3 * fs_info->nodesize;
530 ret = btrfs_qgroup_reserve_meta_prealloc(root,
531 qgroup_num_bytes, true);
532 if (ret)
533 return ret;
534 }
535
536 num_bytes = btrfs_calc_insert_metadata_size(fs_info, items);
537 rsv->space_info = btrfs_find_space_info(fs_info,
538 BTRFS_BLOCK_GROUP_METADATA);
539 ret = btrfs_block_rsv_add(root, rsv, num_bytes,
540 BTRFS_RESERVE_FLUSH_ALL);
541
542 if (ret == -ENOSPC && use_global_rsv)
543 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true);
544
545 if (ret && qgroup_num_bytes)
546 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
547
548 return ret;
549}
550
551void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
552 struct btrfs_block_rsv *rsv)
553{
554 btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
555}
1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/err.h>
20#include <linux/uuid.h>
21#include "ctree.h"
22#include "transaction.h"
23#include "disk-io.h"
24#include "print-tree.h"
25
26/*
27 * Read a root item from the tree. In case we detect a root item smaller then
28 * sizeof(root_item), we know it's an old version of the root structure and
29 * initialize all new fields to zero. The same happens if we detect mismatching
30 * generation numbers as then we know the root was once mounted with an older
31 * kernel that was not aware of the root item structure change.
32 */
33static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
34 struct btrfs_root_item *item)
35{
36 uuid_le uuid;
37 int len;
38 int need_reset = 0;
39
40 len = btrfs_item_size_nr(eb, slot);
41 read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
42 min_t(int, len, (int)sizeof(*item)));
43 if (len < sizeof(*item))
44 need_reset = 1;
45 if (!need_reset && btrfs_root_generation(item)
46 != btrfs_root_generation_v2(item)) {
47 if (btrfs_root_generation_v2(item) != 0) {
48 btrfs_warn(eb->fs_info,
49 "mismatching "
50 "generation and generation_v2 "
51 "found in root item. This root "
52 "was probably mounted with an "
53 "older kernel. Resetting all "
54 "new fields.");
55 }
56 need_reset = 1;
57 }
58 if (need_reset) {
59 memset(&item->generation_v2, 0,
60 sizeof(*item) - offsetof(struct btrfs_root_item,
61 generation_v2));
62
63 uuid_le_gen(&uuid);
64 memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
65 }
66}
67
68/*
69 * btrfs_find_root - lookup the root by the key.
70 * root: the root of the root tree
71 * search_key: the key to search
72 * path: the path we search
73 * root_item: the root item of the tree we look for
74 * root_key: the reak key of the tree we look for
75 *
76 * If ->offset of 'seach_key' is -1ULL, it means we are not sure the offset
77 * of the search key, just lookup the root with the highest offset for a
78 * given objectid.
79 *
80 * If we find something return 0, otherwise > 0, < 0 on error.
81 */
82int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key,
83 struct btrfs_path *path, struct btrfs_root_item *root_item,
84 struct btrfs_key *root_key)
85{
86 struct btrfs_key found_key;
87 struct extent_buffer *l;
88 int ret;
89 int slot;
90
91 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
92 if (ret < 0)
93 return ret;
94
95 if (search_key->offset != -1ULL) { /* the search key is exact */
96 if (ret > 0)
97 goto out;
98 } else {
99 BUG_ON(ret == 0); /* Logical error */
100 if (path->slots[0] == 0)
101 goto out;
102 path->slots[0]--;
103 ret = 0;
104 }
105
106 l = path->nodes[0];
107 slot = path->slots[0];
108
109 btrfs_item_key_to_cpu(l, &found_key, slot);
110 if (found_key.objectid != search_key->objectid ||
111 found_key.type != BTRFS_ROOT_ITEM_KEY) {
112 ret = 1;
113 goto out;
114 }
115
116 if (root_item)
117 btrfs_read_root_item(l, slot, root_item);
118 if (root_key)
119 memcpy(root_key, &found_key, sizeof(found_key));
120out:
121 btrfs_release_path(path);
122 return ret;
123}
124
125void btrfs_set_root_node(struct btrfs_root_item *item,
126 struct extent_buffer *node)
127{
128 btrfs_set_root_bytenr(item, node->start);
129 btrfs_set_root_level(item, btrfs_header_level(node));
130 btrfs_set_root_generation(item, btrfs_header_generation(node));
131}
132
133/*
134 * copy the data in 'item' into the btree
135 */
136int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
137 *root, struct btrfs_key *key, struct btrfs_root_item
138 *item)
139{
140 struct btrfs_path *path;
141 struct extent_buffer *l;
142 int ret;
143 int slot;
144 unsigned long ptr;
145 u32 old_len;
146
147 path = btrfs_alloc_path();
148 if (!path)
149 return -ENOMEM;
150
151 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
152 if (ret < 0) {
153 btrfs_abort_transaction(trans, root, ret);
154 goto out;
155 }
156
157 if (ret != 0) {
158 btrfs_print_leaf(root, path->nodes[0]);
159 btrfs_crit(root->fs_info, "unable to update root key %llu %u %llu",
160 key->objectid, key->type, key->offset);
161 BUG_ON(1);
162 }
163
164 l = path->nodes[0];
165 slot = path->slots[0];
166 ptr = btrfs_item_ptr_offset(l, slot);
167 old_len = btrfs_item_size_nr(l, slot);
168
169 /*
170 * If this is the first time we update the root item which originated
171 * from an older kernel, we need to enlarge the item size to make room
172 * for the added fields.
173 */
174 if (old_len < sizeof(*item)) {
175 btrfs_release_path(path);
176 ret = btrfs_search_slot(trans, root, key, path,
177 -1, 1);
178 if (ret < 0) {
179 btrfs_abort_transaction(trans, root, ret);
180 goto out;
181 }
182
183 ret = btrfs_del_item(trans, root, path);
184 if (ret < 0) {
185 btrfs_abort_transaction(trans, root, ret);
186 goto out;
187 }
188 btrfs_release_path(path);
189 ret = btrfs_insert_empty_item(trans, root, path,
190 key, sizeof(*item));
191 if (ret < 0) {
192 btrfs_abort_transaction(trans, root, ret);
193 goto out;
194 }
195 l = path->nodes[0];
196 slot = path->slots[0];
197 ptr = btrfs_item_ptr_offset(l, slot);
198 }
199
200 /*
201 * Update generation_v2 so at the next mount we know the new root
202 * fields are valid.
203 */
204 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
205
206 write_extent_buffer(l, item, ptr, sizeof(*item));
207 btrfs_mark_buffer_dirty(path->nodes[0]);
208out:
209 btrfs_free_path(path);
210 return ret;
211}
212
213int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
214 struct btrfs_key *key, struct btrfs_root_item *item)
215{
216 /*
217 * Make sure generation v1 and v2 match. See update_root for details.
218 */
219 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
220 return btrfs_insert_item(trans, root, key, item, sizeof(*item));
221}
222
223int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
224{
225 struct extent_buffer *leaf;
226 struct btrfs_path *path;
227 struct btrfs_key key;
228 struct btrfs_key root_key;
229 struct btrfs_root *root;
230 int err = 0;
231 int ret;
232 bool can_recover = true;
233
234 if (tree_root->fs_info->sb->s_flags & MS_RDONLY)
235 can_recover = false;
236
237 path = btrfs_alloc_path();
238 if (!path)
239 return -ENOMEM;
240
241 key.objectid = BTRFS_ORPHAN_OBJECTID;
242 key.type = BTRFS_ORPHAN_ITEM_KEY;
243 key.offset = 0;
244
245 root_key.type = BTRFS_ROOT_ITEM_KEY;
246 root_key.offset = (u64)-1;
247
248 while (1) {
249 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
250 if (ret < 0) {
251 err = ret;
252 break;
253 }
254
255 leaf = path->nodes[0];
256 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
257 ret = btrfs_next_leaf(tree_root, path);
258 if (ret < 0)
259 err = ret;
260 if (ret != 0)
261 break;
262 leaf = path->nodes[0];
263 }
264
265 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
266 btrfs_release_path(path);
267
268 if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
269 key.type != BTRFS_ORPHAN_ITEM_KEY)
270 break;
271
272 root_key.objectid = key.offset;
273 key.offset++;
274
275 root = btrfs_read_fs_root(tree_root, &root_key);
276 err = PTR_ERR_OR_ZERO(root);
277 if (err && err != -ENOENT) {
278 break;
279 } else if (err == -ENOENT) {
280 struct btrfs_trans_handle *trans;
281
282 btrfs_release_path(path);
283
284 trans = btrfs_join_transaction(tree_root);
285 if (IS_ERR(trans)) {
286 err = PTR_ERR(trans);
287 btrfs_std_error(tree_root->fs_info, err,
288 "Failed to start trans to delete "
289 "orphan item");
290 break;
291 }
292 err = btrfs_del_orphan_item(trans, tree_root,
293 root_key.objectid);
294 btrfs_end_transaction(trans, tree_root);
295 if (err) {
296 btrfs_std_error(tree_root->fs_info, err,
297 "Failed to delete root orphan "
298 "item");
299 break;
300 }
301 continue;
302 }
303
304 err = btrfs_init_fs_root(root);
305 if (err) {
306 btrfs_free_fs_root(root);
307 break;
308 }
309
310 set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
311
312 err = btrfs_insert_fs_root(root->fs_info, root);
313 /*
314 * The root might have been inserted already, as before we look
315 * for orphan roots, log replay might have happened, which
316 * triggers a transaction commit and qgroup accounting, which
317 * in turn reads and inserts fs roots while doing backref
318 * walking.
319 */
320 if (err == -EEXIST)
321 err = 0;
322 if (err) {
323 btrfs_free_fs_root(root);
324 break;
325 }
326
327 if (btrfs_root_refs(&root->root_item) == 0)
328 btrfs_add_dead_root(root);
329 }
330
331 btrfs_free_path(path);
332 return err;
333}
334
335/* drop the root item for 'key' from 'root' */
336int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
337 struct btrfs_key *key)
338{
339 struct btrfs_path *path;
340 int ret;
341
342 path = btrfs_alloc_path();
343 if (!path)
344 return -ENOMEM;
345 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
346 if (ret < 0)
347 goto out;
348
349 BUG_ON(ret != 0);
350
351 ret = btrfs_del_item(trans, root, path);
352out:
353 btrfs_free_path(path);
354 return ret;
355}
356
357int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
358 struct btrfs_root *tree_root,
359 u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
360 const char *name, int name_len)
361
362{
363 struct btrfs_path *path;
364 struct btrfs_root_ref *ref;
365 struct extent_buffer *leaf;
366 struct btrfs_key key;
367 unsigned long ptr;
368 int err = 0;
369 int ret;
370
371 path = btrfs_alloc_path();
372 if (!path)
373 return -ENOMEM;
374
375 key.objectid = root_id;
376 key.type = BTRFS_ROOT_BACKREF_KEY;
377 key.offset = ref_id;
378again:
379 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
380 BUG_ON(ret < 0);
381 if (ret == 0) {
382 leaf = path->nodes[0];
383 ref = btrfs_item_ptr(leaf, path->slots[0],
384 struct btrfs_root_ref);
385
386 WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
387 WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
388 ptr = (unsigned long)(ref + 1);
389 WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
390 *sequence = btrfs_root_ref_sequence(leaf, ref);
391
392 ret = btrfs_del_item(trans, tree_root, path);
393 if (ret) {
394 err = ret;
395 goto out;
396 }
397 } else
398 err = -ENOENT;
399
400 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
401 btrfs_release_path(path);
402 key.objectid = ref_id;
403 key.type = BTRFS_ROOT_REF_KEY;
404 key.offset = root_id;
405 goto again;
406 }
407
408out:
409 btrfs_free_path(path);
410 return err;
411}
412
413/*
414 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
415 * or BTRFS_ROOT_BACKREF_KEY.
416 *
417 * The dirid, sequence, name and name_len refer to the directory entry
418 * that is referencing the root.
419 *
420 * For a forward ref, the root_id is the id of the tree referencing
421 * the root and ref_id is the id of the subvol or snapshot.
422 *
423 * For a back ref the root_id is the id of the subvol or snapshot and
424 * ref_id is the id of the tree referencing it.
425 *
426 * Will return 0, -ENOMEM, or anything from the CoW path
427 */
428int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
429 struct btrfs_root *tree_root,
430 u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
431 const char *name, int name_len)
432{
433 struct btrfs_key key;
434 int ret;
435 struct btrfs_path *path;
436 struct btrfs_root_ref *ref;
437 struct extent_buffer *leaf;
438 unsigned long ptr;
439
440 path = btrfs_alloc_path();
441 if (!path)
442 return -ENOMEM;
443
444 key.objectid = root_id;
445 key.type = BTRFS_ROOT_BACKREF_KEY;
446 key.offset = ref_id;
447again:
448 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
449 sizeof(*ref) + name_len);
450 if (ret) {
451 btrfs_abort_transaction(trans, tree_root, ret);
452 btrfs_free_path(path);
453 return ret;
454 }
455
456 leaf = path->nodes[0];
457 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
458 btrfs_set_root_ref_dirid(leaf, ref, dirid);
459 btrfs_set_root_ref_sequence(leaf, ref, sequence);
460 btrfs_set_root_ref_name_len(leaf, ref, name_len);
461 ptr = (unsigned long)(ref + 1);
462 write_extent_buffer(leaf, name, ptr, name_len);
463 btrfs_mark_buffer_dirty(leaf);
464
465 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
466 btrfs_release_path(path);
467 key.objectid = ref_id;
468 key.type = BTRFS_ROOT_REF_KEY;
469 key.offset = root_id;
470 goto again;
471 }
472
473 btrfs_free_path(path);
474 return 0;
475}
476
477/*
478 * Old btrfs forgets to init root_item->flags and root_item->byte_limit
479 * for subvolumes. To work around this problem, we steal a bit from
480 * root_item->inode_item->flags, and use it to indicate if those fields
481 * have been properly initialized.
482 */
483void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
484{
485 u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
486
487 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
488 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
489 btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
490 btrfs_set_root_flags(root_item, 0);
491 btrfs_set_root_limit(root_item, 0);
492 }
493}
494
495void btrfs_update_root_times(struct btrfs_trans_handle *trans,
496 struct btrfs_root *root)
497{
498 struct btrfs_root_item *item = &root->root_item;
499 struct timespec ct = current_fs_time(root->fs_info->sb);
500
501 spin_lock(&root->root_item_lock);
502 btrfs_set_root_ctransid(item, trans->transid);
503 btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
504 btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
505 spin_unlock(&root->root_item_lock);
506}