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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 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}
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}