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