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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
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}
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 "ctree.h"
20#include "transaction.h"
21#include "disk-io.h"
22#include "print-tree.h"
23
24/*
25 * lookup the root with the highest offset for a given objectid. The key we do
26 * find is copied into 'key'. If we find something return 0, otherwise 1, < 0
27 * on error.
28 */
29int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
30 struct btrfs_root_item *item, struct btrfs_key *key)
31{
32 struct btrfs_path *path;
33 struct btrfs_key search_key;
34 struct btrfs_key found_key;
35 struct extent_buffer *l;
36 int ret;
37 int slot;
38
39 search_key.objectid = objectid;
40 search_key.type = BTRFS_ROOT_ITEM_KEY;
41 search_key.offset = (u64)-1;
42
43 path = btrfs_alloc_path();
44 if (!path)
45 return -ENOMEM;
46 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
47 if (ret < 0)
48 goto out;
49
50 BUG_ON(ret == 0);
51 if (path->slots[0] == 0) {
52 ret = 1;
53 goto out;
54 }
55 l = path->nodes[0];
56 slot = path->slots[0] - 1;
57 btrfs_item_key_to_cpu(l, &found_key, slot);
58 if (found_key.objectid != objectid ||
59 found_key.type != BTRFS_ROOT_ITEM_KEY) {
60 ret = 1;
61 goto out;
62 }
63 if (item)
64 read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
65 sizeof(*item));
66 if (key)
67 memcpy(key, &found_key, sizeof(found_key));
68 ret = 0;
69out:
70 btrfs_free_path(path);
71 return ret;
72}
73
74void btrfs_set_root_node(struct btrfs_root_item *item,
75 struct extent_buffer *node)
76{
77 btrfs_set_root_bytenr(item, node->start);
78 btrfs_set_root_level(item, btrfs_header_level(node));
79 btrfs_set_root_generation(item, btrfs_header_generation(node));
80}
81
82/*
83 * copy the data in 'item' into the btree
84 */
85int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
86 *root, struct btrfs_key *key, struct btrfs_root_item
87 *item)
88{
89 struct btrfs_path *path;
90 struct extent_buffer *l;
91 int ret;
92 int slot;
93 unsigned long ptr;
94
95 path = btrfs_alloc_path();
96 if (!path)
97 return -ENOMEM;
98
99 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
100 if (ret < 0) {
101 btrfs_abort_transaction(trans, root, ret);
102 goto out;
103 }
104
105 if (ret != 0) {
106 btrfs_print_leaf(root, path->nodes[0]);
107 printk(KERN_CRIT "unable to update root key %llu %u %llu\n",
108 (unsigned long long)key->objectid, key->type,
109 (unsigned long long)key->offset);
110 BUG_ON(1);
111 }
112
113 l = path->nodes[0];
114 slot = path->slots[0];
115 ptr = btrfs_item_ptr_offset(l, slot);
116 write_extent_buffer(l, item, ptr, sizeof(*item));
117 btrfs_mark_buffer_dirty(path->nodes[0]);
118out:
119 btrfs_free_path(path);
120 return ret;
121}
122
123int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
124 struct btrfs_key *key, struct btrfs_root_item *item)
125{
126 return btrfs_insert_item(trans, root, key, item, sizeof(*item));
127}
128
129/*
130 * at mount time we want to find all the old transaction snapshots that were in
131 * the process of being deleted if we crashed. This is any root item with an
132 * offset lower than the latest root. They need to be queued for deletion to
133 * finish what was happening when we crashed.
134 */
135int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid)
136{
137 struct btrfs_root *dead_root;
138 struct btrfs_root_item *ri;
139 struct btrfs_key key;
140 struct btrfs_key found_key;
141 struct btrfs_path *path;
142 int ret;
143 u32 nritems;
144 struct extent_buffer *leaf;
145 int slot;
146
147 key.objectid = objectid;
148 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
149 key.offset = 0;
150 path = btrfs_alloc_path();
151 if (!path)
152 return -ENOMEM;
153
154again:
155 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
156 if (ret < 0)
157 goto err;
158 while (1) {
159 leaf = path->nodes[0];
160 nritems = btrfs_header_nritems(leaf);
161 slot = path->slots[0];
162 if (slot >= nritems) {
163 ret = btrfs_next_leaf(root, path);
164 if (ret)
165 break;
166 leaf = path->nodes[0];
167 nritems = btrfs_header_nritems(leaf);
168 slot = path->slots[0];
169 }
170 btrfs_item_key_to_cpu(leaf, &key, slot);
171 if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
172 goto next;
173
174 if (key.objectid < objectid)
175 goto next;
176
177 if (key.objectid > objectid)
178 break;
179
180 ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
181 if (btrfs_disk_root_refs(leaf, ri) != 0)
182 goto next;
183
184 memcpy(&found_key, &key, sizeof(key));
185 key.offset++;
186 btrfs_release_path(path);
187 dead_root =
188 btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
189 &found_key);
190 if (IS_ERR(dead_root)) {
191 ret = PTR_ERR(dead_root);
192 goto err;
193 }
194
195 ret = btrfs_add_dead_root(dead_root);
196 if (ret)
197 goto err;
198 goto again;
199next:
200 slot++;
201 path->slots[0]++;
202 }
203 ret = 0;
204err:
205 btrfs_free_path(path);
206 return ret;
207}
208
209int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
210{
211 struct extent_buffer *leaf;
212 struct btrfs_path *path;
213 struct btrfs_key key;
214 struct btrfs_key root_key;
215 struct btrfs_root *root;
216 int err = 0;
217 int ret;
218
219 path = btrfs_alloc_path();
220 if (!path)
221 return -ENOMEM;
222
223 key.objectid = BTRFS_ORPHAN_OBJECTID;
224 key.type = BTRFS_ORPHAN_ITEM_KEY;
225 key.offset = 0;
226
227 root_key.type = BTRFS_ROOT_ITEM_KEY;
228 root_key.offset = (u64)-1;
229
230 while (1) {
231 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
232 if (ret < 0) {
233 err = ret;
234 break;
235 }
236
237 leaf = path->nodes[0];
238 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
239 ret = btrfs_next_leaf(tree_root, path);
240 if (ret < 0)
241 err = ret;
242 if (ret != 0)
243 break;
244 leaf = path->nodes[0];
245 }
246
247 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
248 btrfs_release_path(path);
249
250 if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
251 key.type != BTRFS_ORPHAN_ITEM_KEY)
252 break;
253
254 root_key.objectid = key.offset;
255 key.offset++;
256
257 root = btrfs_read_fs_root_no_name(tree_root->fs_info,
258 &root_key);
259 if (!IS_ERR(root))
260 continue;
261
262 ret = PTR_ERR(root);
263 if (ret != -ENOENT) {
264 err = ret;
265 break;
266 }
267
268 ret = btrfs_find_dead_roots(tree_root, root_key.objectid);
269 if (ret) {
270 err = ret;
271 break;
272 }
273 }
274
275 btrfs_free_path(path);
276 return err;
277}
278
279/* drop the root item for 'key' from 'root' */
280int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
281 struct btrfs_key *key)
282{
283 struct btrfs_path *path;
284 int ret;
285 struct btrfs_root_item *ri;
286 struct extent_buffer *leaf;
287
288 path = btrfs_alloc_path();
289 if (!path)
290 return -ENOMEM;
291 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
292 if (ret < 0)
293 goto out;
294
295 BUG_ON(ret != 0);
296 leaf = path->nodes[0];
297 ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
298
299 ret = btrfs_del_item(trans, root, path);
300out:
301 btrfs_free_path(path);
302 return ret;
303}
304
305int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
306 struct btrfs_root *tree_root,
307 u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
308 const char *name, int name_len)
309
310{
311 struct btrfs_path *path;
312 struct btrfs_root_ref *ref;
313 struct extent_buffer *leaf;
314 struct btrfs_key key;
315 unsigned long ptr;
316 int err = 0;
317 int ret;
318
319 path = btrfs_alloc_path();
320 if (!path)
321 return -ENOMEM;
322
323 key.objectid = root_id;
324 key.type = BTRFS_ROOT_BACKREF_KEY;
325 key.offset = ref_id;
326again:
327 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
328 BUG_ON(ret < 0);
329 if (ret == 0) {
330 leaf = path->nodes[0];
331 ref = btrfs_item_ptr(leaf, path->slots[0],
332 struct btrfs_root_ref);
333
334 WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
335 WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
336 ptr = (unsigned long)(ref + 1);
337 WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
338 *sequence = btrfs_root_ref_sequence(leaf, ref);
339
340 ret = btrfs_del_item(trans, tree_root, path);
341 if (ret) {
342 err = ret;
343 goto out;
344 }
345 } else
346 err = -ENOENT;
347
348 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
349 btrfs_release_path(path);
350 key.objectid = ref_id;
351 key.type = BTRFS_ROOT_REF_KEY;
352 key.offset = root_id;
353 goto again;
354 }
355
356out:
357 btrfs_free_path(path);
358 return err;
359}
360
361int btrfs_find_root_ref(struct btrfs_root *tree_root,
362 struct btrfs_path *path,
363 u64 root_id, u64 ref_id)
364{
365 struct btrfs_key key;
366 int ret;
367
368 key.objectid = root_id;
369 key.type = BTRFS_ROOT_REF_KEY;
370 key.offset = ref_id;
371
372 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
373 return ret;
374}
375
376/*
377 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
378 * or BTRFS_ROOT_BACKREF_KEY.
379 *
380 * The dirid, sequence, name and name_len refer to the directory entry
381 * that is referencing the root.
382 *
383 * For a forward ref, the root_id is the id of the tree referencing
384 * the root and ref_id is the id of the subvol or snapshot.
385 *
386 * For a back ref the root_id is the id of the subvol or snapshot and
387 * ref_id is the id of the tree referencing it.
388 *
389 * Will return 0, -ENOMEM, or anything from the CoW path
390 */
391int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
392 struct btrfs_root *tree_root,
393 u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
394 const char *name, int name_len)
395{
396 struct btrfs_key key;
397 int ret;
398 struct btrfs_path *path;
399 struct btrfs_root_ref *ref;
400 struct extent_buffer *leaf;
401 unsigned long ptr;
402
403 path = btrfs_alloc_path();
404 if (!path)
405 return -ENOMEM;
406
407 key.objectid = root_id;
408 key.type = BTRFS_ROOT_BACKREF_KEY;
409 key.offset = ref_id;
410again:
411 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
412 sizeof(*ref) + name_len);
413 if (ret) {
414 btrfs_abort_transaction(trans, tree_root, ret);
415 btrfs_free_path(path);
416 return ret;
417 }
418
419 leaf = path->nodes[0];
420 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
421 btrfs_set_root_ref_dirid(leaf, ref, dirid);
422 btrfs_set_root_ref_sequence(leaf, ref, sequence);
423 btrfs_set_root_ref_name_len(leaf, ref, name_len);
424 ptr = (unsigned long)(ref + 1);
425 write_extent_buffer(leaf, name, ptr, name_len);
426 btrfs_mark_buffer_dirty(leaf);
427
428 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
429 btrfs_release_path(path);
430 key.objectid = ref_id;
431 key.type = BTRFS_ROOT_REF_KEY;
432 key.offset = root_id;
433 goto again;
434 }
435
436 btrfs_free_path(path);
437 return 0;
438}
439
440/*
441 * Old btrfs forgets to init root_item->flags and root_item->byte_limit
442 * for subvolumes. To work around this problem, we steal a bit from
443 * root_item->inode_item->flags, and use it to indicate if those fields
444 * have been properly initialized.
445 */
446void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
447{
448 u64 inode_flags = le64_to_cpu(root_item->inode.flags);
449
450 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
451 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
452 root_item->inode.flags = cpu_to_le64(inode_flags);
453 root_item->flags = 0;
454 root_item->byte_limit = 0;
455 }
456}