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