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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 printk(KERN_WARNING "BTRFS: mismatching "
49 "generation and generation_v2 "
50 "found in root item. This root "
51 "was probably mounted with an "
52 "older kernel. Resetting all "
53 "new fields.\n");
54 }
55 need_reset = 1;
56 }
57 if (need_reset) {
58 memset(&item->generation_v2, 0,
59 sizeof(*item) - offsetof(struct btrfs_root_item,
60 generation_v2));
61
62 uuid_le_gen(&uuid);
63 memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
64 }
65}
66
67/*
68 * btrfs_find_root - lookup the root by the key.
69 * root: the root of the root tree
70 * search_key: the key to search
71 * path: the path we search
72 * root_item: the root item of the tree we look for
73 * root_key: the reak key of the tree we look for
74 *
75 * If ->offset of 'seach_key' is -1ULL, it means we are not sure the offset
76 * of the search key, just lookup the root with the highest offset for a
77 * given objectid.
78 *
79 * If we find something return 0, otherwise > 0, < 0 on error.
80 */
81int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key,
82 struct btrfs_path *path, struct btrfs_root_item *root_item,
83 struct btrfs_key *root_key)
84{
85 struct btrfs_key found_key;
86 struct extent_buffer *l;
87 int ret;
88 int slot;
89
90 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
91 if (ret < 0)
92 return ret;
93
94 if (search_key->offset != -1ULL) { /* the search key is exact */
95 if (ret > 0)
96 goto out;
97 } else {
98 BUG_ON(ret == 0); /* Logical error */
99 if (path->slots[0] == 0)
100 goto out;
101 path->slots[0]--;
102 ret = 0;
103 }
104
105 l = path->nodes[0];
106 slot = path->slots[0];
107
108 btrfs_item_key_to_cpu(l, &found_key, slot);
109 if (found_key.objectid != search_key->objectid ||
110 found_key.type != BTRFS_ROOT_ITEM_KEY) {
111 ret = 1;
112 goto out;
113 }
114
115 if (root_item)
116 btrfs_read_root_item(l, slot, root_item);
117 if (root_key)
118 memcpy(root_key, &found_key, sizeof(found_key));
119out:
120 btrfs_release_path(path);
121 return ret;
122}
123
124void btrfs_set_root_node(struct btrfs_root_item *item,
125 struct extent_buffer *node)
126{
127 btrfs_set_root_bytenr(item, node->start);
128 btrfs_set_root_level(item, btrfs_header_level(node));
129 btrfs_set_root_generation(item, btrfs_header_generation(node));
130}
131
132/*
133 * copy the data in 'item' into the btree
134 */
135int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
136 *root, struct btrfs_key *key, struct btrfs_root_item
137 *item)
138{
139 struct btrfs_path *path;
140 struct extent_buffer *l;
141 int ret;
142 int slot;
143 unsigned long ptr;
144 int old_len;
145
146 path = btrfs_alloc_path();
147 if (!path)
148 return -ENOMEM;
149
150 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
151 if (ret < 0) {
152 btrfs_abort_transaction(trans, root, ret);
153 goto out;
154 }
155
156 if (ret != 0) {
157 btrfs_print_leaf(root, path->nodes[0]);
158 btrfs_crit(root->fs_info, "unable to update root key %llu %u %llu",
159 key->objectid, key->type, key->offset);
160 BUG_ON(1);
161 }
162
163 l = path->nodes[0];
164 slot = path->slots[0];
165 ptr = btrfs_item_ptr_offset(l, slot);
166 old_len = btrfs_item_size_nr(l, slot);
167
168 /*
169 * If this is the first time we update the root item which originated
170 * from an older kernel, we need to enlarge the item size to make room
171 * for the added fields.
172 */
173 if (old_len < sizeof(*item)) {
174 btrfs_release_path(path);
175 ret = btrfs_search_slot(trans, root, key, path,
176 -1, 1);
177 if (ret < 0) {
178 btrfs_abort_transaction(trans, root, ret);
179 goto out;
180 }
181
182 ret = btrfs_del_item(trans, root, path);
183 if (ret < 0) {
184 btrfs_abort_transaction(trans, root, ret);
185 goto out;
186 }
187 btrfs_release_path(path);
188 ret = btrfs_insert_empty_item(trans, root, path,
189 key, sizeof(*item));
190 if (ret < 0) {
191 btrfs_abort_transaction(trans, root, ret);
192 goto out;
193 }
194 l = path->nodes[0];
195 slot = path->slots[0];
196 ptr = btrfs_item_ptr_offset(l, slot);
197 }
198
199 /*
200 * Update generation_v2 so at the next mount we know the new root
201 * fields are valid.
202 */
203 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
204
205 write_extent_buffer(l, item, ptr, sizeof(*item));
206 btrfs_mark_buffer_dirty(path->nodes[0]);
207out:
208 btrfs_free_path(path);
209 return ret;
210}
211
212int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
213 struct btrfs_key *key, struct btrfs_root_item *item)
214{
215 /*
216 * Make sure generation v1 and v2 match. See update_root for details.
217 */
218 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
219 return btrfs_insert_item(trans, root, key, item, sizeof(*item));
220}
221
222int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
223{
224 struct extent_buffer *leaf;
225 struct btrfs_path *path;
226 struct btrfs_key key;
227 struct btrfs_key root_key;
228 struct btrfs_root *root;
229 int err = 0;
230 int ret;
231 bool can_recover = true;
232
233 if (tree_root->fs_info->sb->s_flags & MS_RDONLY)
234 can_recover = false;
235
236 path = btrfs_alloc_path();
237 if (!path)
238 return -ENOMEM;
239
240 key.objectid = BTRFS_ORPHAN_OBJECTID;
241 key.type = BTRFS_ORPHAN_ITEM_KEY;
242 key.offset = 0;
243
244 root_key.type = BTRFS_ROOT_ITEM_KEY;
245 root_key.offset = (u64)-1;
246
247 while (1) {
248 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
249 if (ret < 0) {
250 err = ret;
251 break;
252 }
253
254 leaf = path->nodes[0];
255 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
256 ret = btrfs_next_leaf(tree_root, path);
257 if (ret < 0)
258 err = ret;
259 if (ret != 0)
260 break;
261 leaf = path->nodes[0];
262 }
263
264 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
265 btrfs_release_path(path);
266
267 if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
268 key.type != BTRFS_ORPHAN_ITEM_KEY)
269 break;
270
271 root_key.objectid = key.offset;
272 key.offset++;
273
274 root = btrfs_read_fs_root(tree_root, &root_key);
275 err = PTR_ERR_OR_ZERO(root);
276 if (err && err != -ENOENT) {
277 break;
278 } else if (err == -ENOENT) {
279 struct btrfs_trans_handle *trans;
280
281 btrfs_release_path(path);
282
283 trans = btrfs_join_transaction(tree_root);
284 if (IS_ERR(trans)) {
285 err = PTR_ERR(trans);
286 btrfs_error(tree_root->fs_info, err,
287 "Failed to start trans to delete "
288 "orphan item");
289 break;
290 }
291 err = btrfs_del_orphan_item(trans, tree_root,
292 root_key.objectid);
293 btrfs_end_transaction(trans, tree_root);
294 if (err) {
295 btrfs_error(tree_root->fs_info, err,
296 "Failed to delete root orphan "
297 "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 root->orphan_item_inserted = 1;
310
311 err = btrfs_insert_fs_root(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 btrfs_add_dead_root(root);
320 }
321
322 btrfs_free_path(path);
323 return err;
324}
325
326/* drop the root item for 'key' from 'root' */
327int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
328 struct btrfs_key *key)
329{
330 struct btrfs_path *path;
331 int ret;
332
333 path = btrfs_alloc_path();
334 if (!path)
335 return -ENOMEM;
336 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
337 if (ret < 0)
338 goto out;
339
340 BUG_ON(ret != 0);
341
342 ret = btrfs_del_item(trans, root, path);
343out:
344 btrfs_free_path(path);
345 return ret;
346}
347
348int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
349 struct btrfs_root *tree_root,
350 u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
351 const char *name, int name_len)
352
353{
354 struct btrfs_path *path;
355 struct btrfs_root_ref *ref;
356 struct extent_buffer *leaf;
357 struct btrfs_key key;
358 unsigned long ptr;
359 int err = 0;
360 int ret;
361
362 path = btrfs_alloc_path();
363 if (!path)
364 return -ENOMEM;
365
366 key.objectid = root_id;
367 key.type = BTRFS_ROOT_BACKREF_KEY;
368 key.offset = ref_id;
369again:
370 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
371 BUG_ON(ret < 0);
372 if (ret == 0) {
373 leaf = path->nodes[0];
374 ref = btrfs_item_ptr(leaf, path->slots[0],
375 struct btrfs_root_ref);
376
377 WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
378 WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
379 ptr = (unsigned long)(ref + 1);
380 WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
381 *sequence = btrfs_root_ref_sequence(leaf, ref);
382
383 ret = btrfs_del_item(trans, tree_root, path);
384 if (ret) {
385 err = ret;
386 goto out;
387 }
388 } else
389 err = -ENOENT;
390
391 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
392 btrfs_release_path(path);
393 key.objectid = ref_id;
394 key.type = BTRFS_ROOT_REF_KEY;
395 key.offset = root_id;
396 goto again;
397 }
398
399out:
400 btrfs_free_path(path);
401 return err;
402}
403
404/*
405 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
406 * or BTRFS_ROOT_BACKREF_KEY.
407 *
408 * The dirid, sequence, name and name_len refer to the directory entry
409 * that is referencing the root.
410 *
411 * For a forward ref, the root_id is the id of the tree referencing
412 * the root and ref_id is the id of the subvol or snapshot.
413 *
414 * For a back ref the root_id is the id of the subvol or snapshot and
415 * ref_id is the id of the tree referencing it.
416 *
417 * Will return 0, -ENOMEM, or anything from the CoW path
418 */
419int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
420 struct btrfs_root *tree_root,
421 u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
422 const char *name, int name_len)
423{
424 struct btrfs_key key;
425 int ret;
426 struct btrfs_path *path;
427 struct btrfs_root_ref *ref;
428 struct extent_buffer *leaf;
429 unsigned long ptr;
430
431 path = btrfs_alloc_path();
432 if (!path)
433 return -ENOMEM;
434
435 key.objectid = root_id;
436 key.type = BTRFS_ROOT_BACKREF_KEY;
437 key.offset = ref_id;
438again:
439 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
440 sizeof(*ref) + name_len);
441 if (ret) {
442 btrfs_abort_transaction(trans, tree_root, ret);
443 btrfs_free_path(path);
444 return ret;
445 }
446
447 leaf = path->nodes[0];
448 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
449 btrfs_set_root_ref_dirid(leaf, ref, dirid);
450 btrfs_set_root_ref_sequence(leaf, ref, sequence);
451 btrfs_set_root_ref_name_len(leaf, ref, name_len);
452 ptr = (unsigned long)(ref + 1);
453 write_extent_buffer(leaf, name, ptr, name_len);
454 btrfs_mark_buffer_dirty(leaf);
455
456 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
457 btrfs_release_path(path);
458 key.objectid = ref_id;
459 key.type = BTRFS_ROOT_REF_KEY;
460 key.offset = root_id;
461 goto again;
462 }
463
464 btrfs_free_path(path);
465 return 0;
466}
467
468/*
469 * Old btrfs forgets to init root_item->flags and root_item->byte_limit
470 * for subvolumes. To work around this problem, we steal a bit from
471 * root_item->inode_item->flags, and use it to indicate if those fields
472 * have been properly initialized.
473 */
474void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
475{
476 u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
477
478 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
479 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
480 btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
481 btrfs_set_root_flags(root_item, 0);
482 btrfs_set_root_limit(root_item, 0);
483 }
484}
485
486void btrfs_update_root_times(struct btrfs_trans_handle *trans,
487 struct btrfs_root *root)
488{
489 struct btrfs_root_item *item = &root->root_item;
490 struct timespec ct = CURRENT_TIME;
491
492 spin_lock(&root->root_item_lock);
493 btrfs_set_root_ctransid(item, trans->transid);
494 btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
495 btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
496 spin_unlock(&root->root_item_lock);
497}
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}