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

source code of linux/fs/btrfs/uuid-tree.c