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