1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) STRATO AG 2013. All rights reserved.
4 */
5
6 #include <linux/uuid.h>
7 #include <asm/unaligned.h>
8 #include "messages.h"
9 #include "ctree.h"
10 #include "transaction.h"
11 #include "disk-io.h"
12 #include "print-tree.h"
13 #include "fs.h"
14 #include "accessors.h"
15 #include "uuid-tree.h"
16
btrfs_uuid_to_key(u8 * uuid,u8 type,struct btrfs_key * key)17 static void btrfs_uuid_to_key(u8 *uuid, u8 type, struct btrfs_key *key)
18 {
19 key->type = type;
20 key->objectid = get_unaligned_le64(uuid);
21 key->offset = get_unaligned_le64(uuid + sizeof(u64));
22 }
23
24 /* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
btrfs_uuid_tree_lookup(struct btrfs_root * uuid_root,u8 * uuid,u8 type,u64 subid)25 static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, u8 *uuid,
26 u8 type, u64 subid)
27 {
28 int ret;
29 struct btrfs_path *path = NULL;
30 struct extent_buffer *eb;
31 int slot;
32 u32 item_size;
33 unsigned long offset;
34 struct btrfs_key key;
35
36 if (WARN_ON_ONCE(!uuid_root)) {
37 ret = -ENOENT;
38 goto out;
39 }
40
41 path = btrfs_alloc_path();
42 if (!path) {
43 ret = -ENOMEM;
44 goto out;
45 }
46
47 btrfs_uuid_to_key(uuid, type, &key);
48 ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
49 if (ret < 0) {
50 goto out;
51 } else if (ret > 0) {
52 ret = -ENOENT;
53 goto out;
54 }
55
56 eb = path->nodes[0];
57 slot = path->slots[0];
58 item_size = btrfs_item_size(eb, slot);
59 offset = btrfs_item_ptr_offset(eb, slot);
60 ret = -ENOENT;
61
62 if (!IS_ALIGNED(item_size, sizeof(u64))) {
63 btrfs_warn(uuid_root->fs_info,
64 "uuid item with illegal size %lu!",
65 (unsigned long)item_size);
66 goto out;
67 }
68 while (item_size) {
69 __le64 data;
70
71 read_extent_buffer(eb, &data, offset, sizeof(data));
72 if (le64_to_cpu(data) == subid) {
73 ret = 0;
74 break;
75 }
76 offset += sizeof(data);
77 item_size -= sizeof(data);
78 }
79
80 out:
81 btrfs_free_path(path);
82 return ret;
83 }
84
btrfs_uuid_tree_add(struct btrfs_trans_handle * trans,u8 * uuid,u8 type,u64 subid_cpu)85 int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, u8 *uuid, u8 type,
86 u64 subid_cpu)
87 {
88 struct btrfs_fs_info *fs_info = trans->fs_info;
89 struct btrfs_root *uuid_root = fs_info->uuid_root;
90 int ret;
91 struct btrfs_path *path = NULL;
92 struct btrfs_key key;
93 struct extent_buffer *eb;
94 int slot;
95 unsigned long offset;
96 __le64 subid_le;
97
98 ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
99 if (ret != -ENOENT)
100 return ret;
101
102 if (WARN_ON_ONCE(!uuid_root)) {
103 ret = -EINVAL;
104 goto out;
105 }
106
107 btrfs_uuid_to_key(uuid, type, &key);
108
109 path = btrfs_alloc_path();
110 if (!path) {
111 ret = -ENOMEM;
112 goto out;
113 }
114
115 ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
116 sizeof(subid_le));
117 if (ret >= 0) {
118 /* Add an item for the type for the first time */
119 eb = path->nodes[0];
120 slot = path->slots[0];
121 offset = btrfs_item_ptr_offset(eb, slot);
122 } else if (ret == -EEXIST) {
123 /*
124 * An item with that type already exists.
125 * Extend the item and store the new subid at the end.
126 */
127 btrfs_extend_item(path, sizeof(subid_le));
128 eb = path->nodes[0];
129 slot = path->slots[0];
130 offset = btrfs_item_ptr_offset(eb, slot);
131 offset += btrfs_item_size(eb, slot) - sizeof(subid_le);
132 } else {
133 btrfs_warn(fs_info,
134 "insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!",
135 ret, key.objectid, key.offset, type);
136 goto out;
137 }
138
139 ret = 0;
140 subid_le = cpu_to_le64(subid_cpu);
141 write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
142 btrfs_mark_buffer_dirty(eb);
143
144 out:
145 btrfs_free_path(path);
146 return ret;
147 }
148
btrfs_uuid_tree_remove(struct btrfs_trans_handle * trans,u8 * uuid,u8 type,u64 subid)149 int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, u8 *uuid, u8 type,
150 u64 subid)
151 {
152 struct btrfs_fs_info *fs_info = trans->fs_info;
153 struct btrfs_root *uuid_root = fs_info->uuid_root;
154 int ret;
155 struct btrfs_path *path = NULL;
156 struct btrfs_key key;
157 struct extent_buffer *eb;
158 int slot;
159 unsigned long offset;
160 u32 item_size;
161 unsigned long move_dst;
162 unsigned long move_src;
163 unsigned long move_len;
164
165 if (WARN_ON_ONCE(!uuid_root)) {
166 ret = -EINVAL;
167 goto out;
168 }
169
170 btrfs_uuid_to_key(uuid, type, &key);
171
172 path = btrfs_alloc_path();
173 if (!path) {
174 ret = -ENOMEM;
175 goto out;
176 }
177
178 ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
179 if (ret < 0) {
180 btrfs_warn(fs_info, "error %d while searching for uuid item!",
181 ret);
182 goto out;
183 }
184 if (ret > 0) {
185 ret = -ENOENT;
186 goto out;
187 }
188
189 eb = path->nodes[0];
190 slot = path->slots[0];
191 offset = btrfs_item_ptr_offset(eb, slot);
192 item_size = btrfs_item_size(eb, slot);
193 if (!IS_ALIGNED(item_size, sizeof(u64))) {
194 btrfs_warn(fs_info, "uuid item with illegal size %lu!",
195 (unsigned long)item_size);
196 ret = -ENOENT;
197 goto out;
198 }
199 while (item_size) {
200 __le64 read_subid;
201
202 read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
203 if (le64_to_cpu(read_subid) == subid)
204 break;
205 offset += sizeof(read_subid);
206 item_size -= sizeof(read_subid);
207 }
208
209 if (!item_size) {
210 ret = -ENOENT;
211 goto out;
212 }
213
214 item_size = btrfs_item_size(eb, slot);
215 if (item_size == sizeof(subid)) {
216 ret = btrfs_del_item(trans, uuid_root, path);
217 goto out;
218 }
219
220 move_dst = offset;
221 move_src = offset + sizeof(subid);
222 move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
223 memmove_extent_buffer(eb, move_dst, move_src, move_len);
224 btrfs_truncate_item(path, item_size - sizeof(subid), 1);
225
226 out:
227 btrfs_free_path(path);
228 return ret;
229 }
230
btrfs_uuid_iter_rem(struct btrfs_root * uuid_root,u8 * uuid,u8 type,u64 subid)231 static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
232 u64 subid)
233 {
234 struct btrfs_trans_handle *trans;
235 int ret;
236
237 /* 1 - for the uuid item */
238 trans = btrfs_start_transaction(uuid_root, 1);
239 if (IS_ERR(trans)) {
240 ret = PTR_ERR(trans);
241 goto out;
242 }
243
244 ret = btrfs_uuid_tree_remove(trans, uuid, type, subid);
245 btrfs_end_transaction(trans);
246
247 out:
248 return ret;
249 }
250
251 /*
252 * Check if there's an matching subvolume for given UUID
253 *
254 * Return:
255 * 0 check succeeded, the entry is not outdated
256 * > 0 if the check failed, the caller should remove the entry
257 * < 0 if an error occurred
258 */
btrfs_check_uuid_tree_entry(struct btrfs_fs_info * fs_info,u8 * uuid,u8 type,u64 subvolid)259 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
260 u8 *uuid, u8 type, u64 subvolid)
261 {
262 int ret = 0;
263 struct btrfs_root *subvol_root;
264
265 if (type != BTRFS_UUID_KEY_SUBVOL &&
266 type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
267 goto out;
268
269 subvol_root = btrfs_get_fs_root(fs_info, subvolid, true);
270 if (IS_ERR(subvol_root)) {
271 ret = PTR_ERR(subvol_root);
272 if (ret == -ENOENT)
273 ret = 1;
274 goto out;
275 }
276
277 switch (type) {
278 case BTRFS_UUID_KEY_SUBVOL:
279 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
280 ret = 1;
281 break;
282 case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
283 if (memcmp(uuid, subvol_root->root_item.received_uuid,
284 BTRFS_UUID_SIZE))
285 ret = 1;
286 break;
287 }
288 btrfs_put_root(subvol_root);
289 out:
290 return ret;
291 }
292
btrfs_uuid_tree_iterate(struct btrfs_fs_info * fs_info)293 int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info)
294 {
295 struct btrfs_root *root = fs_info->uuid_root;
296 struct btrfs_key key;
297 struct btrfs_path *path;
298 int ret = 0;
299 struct extent_buffer *leaf;
300 int slot;
301 u32 item_size;
302 unsigned long offset;
303
304 path = btrfs_alloc_path();
305 if (!path) {
306 ret = -ENOMEM;
307 goto out;
308 }
309
310 key.objectid = 0;
311 key.type = 0;
312 key.offset = 0;
313
314 again_search_slot:
315 ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
316 if (ret) {
317 if (ret > 0)
318 ret = 0;
319 goto out;
320 }
321
322 while (1) {
323 if (btrfs_fs_closing(fs_info)) {
324 ret = -EINTR;
325 goto out;
326 }
327 cond_resched();
328 leaf = path->nodes[0];
329 slot = path->slots[0];
330 btrfs_item_key_to_cpu(leaf, &key, slot);
331
332 if (key.type != BTRFS_UUID_KEY_SUBVOL &&
333 key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
334 goto skip;
335
336 offset = btrfs_item_ptr_offset(leaf, slot);
337 item_size = btrfs_item_size(leaf, slot);
338 if (!IS_ALIGNED(item_size, sizeof(u64))) {
339 btrfs_warn(fs_info,
340 "uuid item with illegal size %lu!",
341 (unsigned long)item_size);
342 goto skip;
343 }
344 while (item_size) {
345 u8 uuid[BTRFS_UUID_SIZE];
346 __le64 subid_le;
347 u64 subid_cpu;
348
349 put_unaligned_le64(key.objectid, uuid);
350 put_unaligned_le64(key.offset, uuid + sizeof(u64));
351 read_extent_buffer(leaf, &subid_le, offset,
352 sizeof(subid_le));
353 subid_cpu = le64_to_cpu(subid_le);
354 ret = btrfs_check_uuid_tree_entry(fs_info, uuid,
355 key.type, subid_cpu);
356 if (ret < 0)
357 goto out;
358 if (ret > 0) {
359 btrfs_release_path(path);
360 ret = btrfs_uuid_iter_rem(root, uuid, key.type,
361 subid_cpu);
362 if (ret == 0) {
363 /*
364 * this might look inefficient, but the
365 * justification is that it is an
366 * exception that check_func returns 1,
367 * and that in the regular case only one
368 * entry per UUID exists.
369 */
370 goto again_search_slot;
371 }
372 if (ret < 0 && ret != -ENOENT)
373 goto out;
374 key.offset++;
375 goto again_search_slot;
376 }
377 item_size -= sizeof(subid_le);
378 offset += sizeof(subid_le);
379 }
380
381 skip:
382 ret = btrfs_next_item(root, path);
383 if (ret == 0)
384 continue;
385 else if (ret > 0)
386 ret = 0;
387 break;
388 }
389
390 out:
391 btrfs_free_path(path);
392 return ret;
393 }
394
