Loading...
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/*
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}