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f7d0fe02 KW |
1 | /* |
2 | * Block driver for the QCOW version 2 format | |
3 | * | |
4 | * Copyright (c) 2004-2006 Fabrice Bellard | |
5 | * | |
6 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
7 | * of this software and associated documentation files (the "Software"), to deal | |
8 | * in the Software without restriction, including without limitation the rights | |
9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
10 | * copies of the Software, and to permit persons to whom the Software is | |
11 | * furnished to do so, subject to the following conditions: | |
12 | * | |
13 | * The above copyright notice and this permission notice shall be included in | |
14 | * all copies or substantial portions of the Software. | |
15 | * | |
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
19 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
22 | * THE SOFTWARE. | |
23 | */ | |
24 | ||
25 | #include "qemu-common.h" | |
26 | #include "block_int.h" | |
27 | #include "block/qcow2.h" | |
28 | ||
29 | static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size); | |
30 | static int update_refcount(BlockDriverState *bs, | |
31 | int64_t offset, int64_t length, | |
32 | int addend); | |
33 | ||
3b88e52b KW |
34 | |
35 | static int cache_refcount_updates = 0; | |
36 | ||
37 | static int write_refcount_block(BDRVQcowState *s) | |
38 | { | |
39 | size_t size = s->cluster_size; | |
40 | ||
41 | if (s->refcount_block_cache_offset == 0) { | |
42 | return 0; | |
43 | } | |
44 | ||
45 | if (bdrv_pwrite(s->hd, s->refcount_block_cache_offset, | |
46 | s->refcount_block_cache, size) != size) | |
47 | { | |
48 | return -EIO; | |
49 | } | |
50 | ||
51 | return 0; | |
52 | } | |
53 | ||
f7d0fe02 KW |
54 | /*********************************************************/ |
55 | /* refcount handling */ | |
56 | ||
ed6ccf0f | 57 | int qcow2_refcount_init(BlockDriverState *bs) |
f7d0fe02 KW |
58 | { |
59 | BDRVQcowState *s = bs->opaque; | |
60 | int ret, refcount_table_size2, i; | |
61 | ||
62 | s->refcount_block_cache = qemu_malloc(s->cluster_size); | |
63 | refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); | |
64 | s->refcount_table = qemu_malloc(refcount_table_size2); | |
65 | if (s->refcount_table_size > 0) { | |
66 | ret = bdrv_pread(s->hd, s->refcount_table_offset, | |
67 | s->refcount_table, refcount_table_size2); | |
68 | if (ret != refcount_table_size2) | |
69 | goto fail; | |
70 | for(i = 0; i < s->refcount_table_size; i++) | |
71 | be64_to_cpus(&s->refcount_table[i]); | |
72 | } | |
73 | return 0; | |
74 | fail: | |
75 | return -ENOMEM; | |
76 | } | |
77 | ||
ed6ccf0f | 78 | void qcow2_refcount_close(BlockDriverState *bs) |
f7d0fe02 KW |
79 | { |
80 | BDRVQcowState *s = bs->opaque; | |
81 | qemu_free(s->refcount_block_cache); | |
82 | qemu_free(s->refcount_table); | |
83 | } | |
84 | ||
85 | ||
86 | static int load_refcount_block(BlockDriverState *bs, | |
87 | int64_t refcount_block_offset) | |
88 | { | |
89 | BDRVQcowState *s = bs->opaque; | |
90 | int ret; | |
3b88e52b KW |
91 | |
92 | if (cache_refcount_updates) { | |
93 | write_refcount_block(s); | |
94 | } | |
95 | ||
f7d0fe02 KW |
96 | ret = bdrv_pread(s->hd, refcount_block_offset, s->refcount_block_cache, |
97 | s->cluster_size); | |
98 | if (ret != s->cluster_size) | |
99 | return -EIO; | |
100 | s->refcount_block_cache_offset = refcount_block_offset; | |
101 | return 0; | |
102 | } | |
103 | ||
104 | static int get_refcount(BlockDriverState *bs, int64_t cluster_index) | |
105 | { | |
106 | BDRVQcowState *s = bs->opaque; | |
107 | int refcount_table_index, block_index; | |
108 | int64_t refcount_block_offset; | |
109 | ||
110 | refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
111 | if (refcount_table_index >= s->refcount_table_size) | |
112 | return 0; | |
113 | refcount_block_offset = s->refcount_table[refcount_table_index]; | |
114 | if (!refcount_block_offset) | |
115 | return 0; | |
116 | if (refcount_block_offset != s->refcount_block_cache_offset) { | |
117 | /* better than nothing: return allocated if read error */ | |
118 | if (load_refcount_block(bs, refcount_block_offset) < 0) | |
119 | return 1; | |
120 | } | |
121 | block_index = cluster_index & | |
122 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
123 | return be16_to_cpu(s->refcount_block_cache[block_index]); | |
124 | } | |
125 | ||
05121aed KW |
126 | /* |
127 | * Rounds the refcount table size up to avoid growing the table for each single | |
128 | * refcount block that is allocated. | |
129 | */ | |
130 | static unsigned int next_refcount_table_size(BDRVQcowState *s, | |
131 | unsigned int min_size) | |
132 | { | |
133 | unsigned int min_clusters = (min_size >> (s->cluster_bits - 3)) + 1; | |
134 | unsigned int refcount_table_clusters = | |
135 | MAX(1, s->refcount_table_size >> (s->cluster_bits - 3)); | |
136 | ||
137 | while (min_clusters > refcount_table_clusters) { | |
138 | refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; | |
139 | } | |
140 | ||
141 | return refcount_table_clusters << (s->cluster_bits - 3); | |
142 | } | |
143 | ||
f7d0fe02 KW |
144 | static int grow_refcount_table(BlockDriverState *bs, int min_size) |
145 | { | |
146 | BDRVQcowState *s = bs->opaque; | |
147 | int new_table_size, new_table_size2, refcount_table_clusters, i, ret; | |
148 | uint64_t *new_table; | |
149 | int64_t table_offset; | |
150 | uint8_t data[12]; | |
151 | int old_table_size; | |
152 | int64_t old_table_offset; | |
153 | ||
154 | if (min_size <= s->refcount_table_size) | |
155 | return 0; | |
156 | /* compute new table size */ | |
05121aed | 157 | new_table_size = next_refcount_table_size(s, min_size); |
f7d0fe02 KW |
158 | #ifdef DEBUG_ALLOC2 |
159 | printf("grow_refcount_table from %d to %d\n", | |
160 | s->refcount_table_size, | |
161 | new_table_size); | |
162 | #endif | |
163 | new_table_size2 = new_table_size * sizeof(uint64_t); | |
164 | new_table = qemu_mallocz(new_table_size2); | |
165 | memcpy(new_table, s->refcount_table, | |
166 | s->refcount_table_size * sizeof(uint64_t)); | |
167 | for(i = 0; i < s->refcount_table_size; i++) | |
168 | cpu_to_be64s(&new_table[i]); | |
169 | /* Note: we cannot update the refcount now to avoid recursion */ | |
170 | table_offset = alloc_clusters_noref(bs, new_table_size2); | |
171 | ret = bdrv_pwrite(s->hd, table_offset, new_table, new_table_size2); | |
172 | if (ret != new_table_size2) | |
173 | goto fail; | |
174 | for(i = 0; i < s->refcount_table_size; i++) | |
175 | be64_to_cpus(&new_table[i]); | |
176 | ||
177 | cpu_to_be64w((uint64_t*)data, table_offset); | |
178 | cpu_to_be32w((uint32_t*)(data + 8), refcount_table_clusters); | |
f2b7c8b3 KW |
179 | ret = bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset), |
180 | data, sizeof(data)); | |
181 | if (ret != sizeof(data)) { | |
f7d0fe02 | 182 | goto fail; |
f2b7c8b3 KW |
183 | } |
184 | ||
f7d0fe02 KW |
185 | qemu_free(s->refcount_table); |
186 | old_table_offset = s->refcount_table_offset; | |
187 | old_table_size = s->refcount_table_size; | |
188 | s->refcount_table = new_table; | |
189 | s->refcount_table_size = new_table_size; | |
190 | s->refcount_table_offset = table_offset; | |
191 | ||
192 | update_refcount(bs, table_offset, new_table_size2, 1); | |
ed6ccf0f | 193 | qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t)); |
f7d0fe02 KW |
194 | return 0; |
195 | fail: | |
f7d0fe02 | 196 | qemu_free(new_table); |
f2b7c8b3 | 197 | return ret < 0 ? ret : -EIO; |
f7d0fe02 KW |
198 | } |
199 | ||
200 | ||
201 | static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index) | |
202 | { | |
203 | BDRVQcowState *s = bs->opaque; | |
204 | int64_t offset, refcount_block_offset; | |
80ee15a6 KW |
205 | unsigned int refcount_table_index; |
206 | int ret; | |
f7d0fe02 | 207 | uint64_t data64; |
3b88e52b | 208 | int cache = cache_refcount_updates; |
f7d0fe02 KW |
209 | |
210 | /* Find L1 index and grow refcount table if needed */ | |
211 | refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
212 | if (refcount_table_index >= s->refcount_table_size) { | |
213 | ret = grow_refcount_table(bs, refcount_table_index + 1); | |
214 | if (ret < 0) | |
215 | return ret; | |
216 | } | |
217 | ||
218 | /* Load or allocate the refcount block */ | |
219 | refcount_block_offset = s->refcount_table[refcount_table_index]; | |
220 | if (!refcount_block_offset) { | |
3b88e52b KW |
221 | if (cache_refcount_updates) { |
222 | write_refcount_block(s); | |
223 | cache_refcount_updates = 0; | |
224 | } | |
f7d0fe02 KW |
225 | /* create a new refcount block */ |
226 | /* Note: we cannot update the refcount now to avoid recursion */ | |
227 | offset = alloc_clusters_noref(bs, s->cluster_size); | |
228 | memset(s->refcount_block_cache, 0, s->cluster_size); | |
229 | ret = bdrv_pwrite(s->hd, offset, s->refcount_block_cache, s->cluster_size); | |
230 | if (ret != s->cluster_size) | |
231 | return -EINVAL; | |
232 | s->refcount_table[refcount_table_index] = offset; | |
233 | data64 = cpu_to_be64(offset); | |
234 | ret = bdrv_pwrite(s->hd, s->refcount_table_offset + | |
235 | refcount_table_index * sizeof(uint64_t), | |
236 | &data64, sizeof(data64)); | |
237 | if (ret != sizeof(data64)) | |
238 | return -EINVAL; | |
239 | ||
240 | refcount_block_offset = offset; | |
241 | s->refcount_block_cache_offset = offset; | |
242 | update_refcount(bs, offset, s->cluster_size, 1); | |
3b88e52b | 243 | cache_refcount_updates = cache; |
f7d0fe02 KW |
244 | } else { |
245 | if (refcount_block_offset != s->refcount_block_cache_offset) { | |
246 | if (load_refcount_block(bs, refcount_block_offset) < 0) | |
247 | return -EIO; | |
248 | } | |
249 | } | |
250 | ||
251 | return refcount_block_offset; | |
252 | } | |
253 | ||
9923e05e KW |
254 | #define REFCOUNTS_PER_SECTOR (512 >> REFCOUNT_SHIFT) |
255 | static int write_refcount_block_entries(BDRVQcowState *s, | |
256 | int64_t refcount_block_offset, int first_index, int last_index) | |
257 | { | |
258 | size_t size; | |
259 | ||
3b88e52b KW |
260 | if (cache_refcount_updates) { |
261 | return 0; | |
262 | } | |
263 | ||
9923e05e KW |
264 | first_index &= ~(REFCOUNTS_PER_SECTOR - 1); |
265 | last_index = (last_index + REFCOUNTS_PER_SECTOR) | |
266 | & ~(REFCOUNTS_PER_SECTOR - 1); | |
267 | ||
268 | size = (last_index - first_index) << REFCOUNT_SHIFT; | |
269 | if (bdrv_pwrite(s->hd, | |
270 | refcount_block_offset + (first_index << REFCOUNT_SHIFT), | |
271 | &s->refcount_block_cache[first_index], size) != size) | |
272 | { | |
273 | return -EIO; | |
274 | } | |
275 | ||
276 | return 0; | |
277 | } | |
278 | ||
f7d0fe02 | 279 | /* XXX: cache several refcount block clusters ? */ |
db3a964f KW |
280 | static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
281 | int64_t offset, int64_t length, int addend) | |
f7d0fe02 KW |
282 | { |
283 | BDRVQcowState *s = bs->opaque; | |
284 | int64_t start, last, cluster_offset; | |
285 | int64_t refcount_block_offset = 0; | |
286 | int64_t table_index = -1, old_table_index; | |
287 | int first_index = -1, last_index = -1; | |
09508d13 | 288 | int ret; |
f7d0fe02 KW |
289 | |
290 | #ifdef DEBUG_ALLOC2 | |
0bf9e31a | 291 | printf("update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", |
f7d0fe02 KW |
292 | offset, length, addend); |
293 | #endif | |
7322afe7 | 294 | if (length < 0) { |
f7d0fe02 | 295 | return -EINVAL; |
7322afe7 KW |
296 | } else if (length == 0) { |
297 | return 0; | |
298 | } | |
299 | ||
f7d0fe02 KW |
300 | start = offset & ~(s->cluster_size - 1); |
301 | last = (offset + length - 1) & ~(s->cluster_size - 1); | |
302 | for(cluster_offset = start; cluster_offset <= last; | |
303 | cluster_offset += s->cluster_size) | |
304 | { | |
305 | int block_index, refcount; | |
306 | int64_t cluster_index = cluster_offset >> s->cluster_bits; | |
09508d13 | 307 | int64_t new_block; |
f7d0fe02 KW |
308 | |
309 | /* Only write refcount block to disk when we are done with it */ | |
310 | old_table_index = table_index; | |
311 | table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
312 | if ((old_table_index >= 0) && (table_index != old_table_index)) { | |
9923e05e KW |
313 | |
314 | if (write_refcount_block_entries(s, refcount_block_offset, | |
315 | first_index, last_index) < 0) | |
f7d0fe02 KW |
316 | { |
317 | return -EIO; | |
318 | } | |
319 | ||
320 | first_index = -1; | |
321 | last_index = -1; | |
322 | } | |
323 | ||
324 | /* Load the refcount block and allocate it if needed */ | |
09508d13 KW |
325 | new_block = alloc_refcount_block(bs, cluster_index); |
326 | if (new_block < 0) { | |
327 | ret = new_block; | |
328 | goto fail; | |
f7d0fe02 | 329 | } |
09508d13 | 330 | refcount_block_offset = new_block; |
f7d0fe02 KW |
331 | |
332 | /* we can update the count and save it */ | |
333 | block_index = cluster_index & | |
334 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
335 | if (first_index == -1 || block_index < first_index) { | |
336 | first_index = block_index; | |
337 | } | |
338 | if (block_index > last_index) { | |
339 | last_index = block_index; | |
340 | } | |
341 | ||
342 | refcount = be16_to_cpu(s->refcount_block_cache[block_index]); | |
343 | refcount += addend; | |
09508d13 KW |
344 | if (refcount < 0 || refcount > 0xffff) { |
345 | ret = -EINVAL; | |
346 | goto fail; | |
347 | } | |
f7d0fe02 KW |
348 | if (refcount == 0 && cluster_index < s->free_cluster_index) { |
349 | s->free_cluster_index = cluster_index; | |
350 | } | |
351 | s->refcount_block_cache[block_index] = cpu_to_be16(refcount); | |
352 | } | |
353 | ||
09508d13 KW |
354 | ret = 0; |
355 | fail: | |
356 | ||
f7d0fe02 KW |
357 | /* Write last changed block to disk */ |
358 | if (refcount_block_offset != 0) { | |
9923e05e KW |
359 | if (write_refcount_block_entries(s, refcount_block_offset, |
360 | first_index, last_index) < 0) | |
f7d0fe02 | 361 | { |
09508d13 | 362 | return ret < 0 ? ret : -EIO; |
f7d0fe02 KW |
363 | } |
364 | } | |
365 | ||
09508d13 KW |
366 | /* |
367 | * Try do undo any updates if an error is returned (This may succeed in | |
368 | * some cases like ENOSPC for allocating a new refcount block) | |
369 | */ | |
370 | if (ret < 0) { | |
371 | int dummy; | |
372 | dummy = update_refcount(bs, offset, cluster_offset - offset, -addend); | |
373 | } | |
374 | ||
375 | return ret; | |
f7d0fe02 KW |
376 | } |
377 | ||
378 | /* addend must be 1 or -1 */ | |
379 | static int update_cluster_refcount(BlockDriverState *bs, | |
380 | int64_t cluster_index, | |
381 | int addend) | |
382 | { | |
383 | BDRVQcowState *s = bs->opaque; | |
384 | int ret; | |
385 | ||
386 | ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend); | |
387 | if (ret < 0) { | |
388 | return ret; | |
389 | } | |
390 | ||
391 | return get_refcount(bs, cluster_index); | |
392 | } | |
393 | ||
394 | ||
395 | ||
396 | /*********************************************************/ | |
397 | /* cluster allocation functions */ | |
398 | ||
399 | ||
400 | ||
401 | /* return < 0 if error */ | |
402 | static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size) | |
403 | { | |
404 | BDRVQcowState *s = bs->opaque; | |
405 | int i, nb_clusters; | |
406 | ||
407 | nb_clusters = size_to_clusters(s, size); | |
408 | retry: | |
409 | for(i = 0; i < nb_clusters; i++) { | |
410 | int64_t i = s->free_cluster_index++; | |
411 | if (get_refcount(bs, i) != 0) | |
412 | goto retry; | |
413 | } | |
414 | #ifdef DEBUG_ALLOC2 | |
0bf9e31a | 415 | printf("alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n", |
f7d0fe02 KW |
416 | size, |
417 | (s->free_cluster_index - nb_clusters) << s->cluster_bits); | |
418 | #endif | |
419 | return (s->free_cluster_index - nb_clusters) << s->cluster_bits; | |
420 | } | |
421 | ||
ed6ccf0f | 422 | int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size) |
f7d0fe02 KW |
423 | { |
424 | int64_t offset; | |
db3a964f | 425 | int ret; |
f7d0fe02 KW |
426 | |
427 | offset = alloc_clusters_noref(bs, size); | |
db3a964f KW |
428 | ret = update_refcount(bs, offset, size, 1); |
429 | if (ret < 0) { | |
430 | return ret; | |
431 | } | |
f7d0fe02 KW |
432 | return offset; |
433 | } | |
434 | ||
435 | /* only used to allocate compressed sectors. We try to allocate | |
436 | contiguous sectors. size must be <= cluster_size */ | |
ed6ccf0f | 437 | int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) |
f7d0fe02 KW |
438 | { |
439 | BDRVQcowState *s = bs->opaque; | |
440 | int64_t offset, cluster_offset; | |
441 | int free_in_cluster; | |
442 | ||
443 | assert(size > 0 && size <= s->cluster_size); | |
444 | if (s->free_byte_offset == 0) { | |
ed6ccf0f | 445 | s->free_byte_offset = qcow2_alloc_clusters(bs, s->cluster_size); |
5d757b56 KW |
446 | if (s->free_byte_offset < 0) { |
447 | return s->free_byte_offset; | |
448 | } | |
f7d0fe02 KW |
449 | } |
450 | redo: | |
451 | free_in_cluster = s->cluster_size - | |
452 | (s->free_byte_offset & (s->cluster_size - 1)); | |
453 | if (size <= free_in_cluster) { | |
454 | /* enough space in current cluster */ | |
455 | offset = s->free_byte_offset; | |
456 | s->free_byte_offset += size; | |
457 | free_in_cluster -= size; | |
458 | if (free_in_cluster == 0) | |
459 | s->free_byte_offset = 0; | |
460 | if ((offset & (s->cluster_size - 1)) != 0) | |
461 | update_cluster_refcount(bs, offset >> s->cluster_bits, 1); | |
462 | } else { | |
ed6ccf0f | 463 | offset = qcow2_alloc_clusters(bs, s->cluster_size); |
5d757b56 KW |
464 | if (offset < 0) { |
465 | return offset; | |
466 | } | |
f7d0fe02 KW |
467 | cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1); |
468 | if ((cluster_offset + s->cluster_size) == offset) { | |
469 | /* we are lucky: contiguous data */ | |
470 | offset = s->free_byte_offset; | |
471 | update_cluster_refcount(bs, offset >> s->cluster_bits, 1); | |
472 | s->free_byte_offset += size; | |
473 | } else { | |
474 | s->free_byte_offset = offset; | |
475 | goto redo; | |
476 | } | |
477 | } | |
478 | return offset; | |
479 | } | |
480 | ||
ed6ccf0f | 481 | void qcow2_free_clusters(BlockDriverState *bs, |
f7d0fe02 KW |
482 | int64_t offset, int64_t size) |
483 | { | |
db3a964f KW |
484 | int ret; |
485 | ||
486 | ret = update_refcount(bs, offset, size, -1); | |
487 | if (ret < 0) { | |
488 | fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret)); | |
489 | abort(); | |
490 | } | |
f7d0fe02 KW |
491 | } |
492 | ||
45aba42f KW |
493 | /* |
494 | * free_any_clusters | |
495 | * | |
496 | * free clusters according to its type: compressed or not | |
497 | * | |
498 | */ | |
499 | ||
ed6ccf0f | 500 | void qcow2_free_any_clusters(BlockDriverState *bs, |
45aba42f KW |
501 | uint64_t cluster_offset, int nb_clusters) |
502 | { | |
503 | BDRVQcowState *s = bs->opaque; | |
504 | ||
505 | /* free the cluster */ | |
506 | ||
507 | if (cluster_offset & QCOW_OFLAG_COMPRESSED) { | |
508 | int nb_csectors; | |
509 | nb_csectors = ((cluster_offset >> s->csize_shift) & | |
510 | s->csize_mask) + 1; | |
ed6ccf0f KW |
511 | qcow2_free_clusters(bs, |
512 | (cluster_offset & s->cluster_offset_mask) & ~511, | |
513 | nb_csectors * 512); | |
45aba42f KW |
514 | return; |
515 | } | |
516 | ||
ed6ccf0f | 517 | qcow2_free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits); |
45aba42f KW |
518 | |
519 | return; | |
520 | } | |
521 | ||
f7d0fe02 KW |
522 | |
523 | ||
524 | /*********************************************************/ | |
525 | /* snapshots and image creation */ | |
526 | ||
527 | ||
528 | ||
ed6ccf0f KW |
529 | void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset, |
530 | int64_t size) | |
f7d0fe02 KW |
531 | { |
532 | int refcount; | |
533 | int64_t start, last, cluster_offset; | |
534 | uint16_t *p; | |
535 | ||
536 | start = offset & ~(s->cluster_size - 1); | |
537 | last = (offset + size - 1) & ~(s->cluster_size - 1); | |
538 | for(cluster_offset = start; cluster_offset <= last; | |
539 | cluster_offset += s->cluster_size) { | |
540 | p = &s->refcount_block[cluster_offset >> s->cluster_bits]; | |
541 | refcount = be16_to_cpu(*p); | |
542 | refcount++; | |
543 | *p = cpu_to_be16(refcount); | |
544 | } | |
545 | } | |
546 | ||
547 | /* update the refcounts of snapshots and the copied flag */ | |
ed6ccf0f KW |
548 | int qcow2_update_snapshot_refcount(BlockDriverState *bs, |
549 | int64_t l1_table_offset, int l1_size, int addend) | |
f7d0fe02 KW |
550 | { |
551 | BDRVQcowState *s = bs->opaque; | |
552 | uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; | |
553 | int64_t old_offset, old_l2_offset; | |
554 | int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount; | |
555 | ||
ed6ccf0f | 556 | qcow2_l2_cache_reset(bs); |
3b88e52b | 557 | cache_refcount_updates = 1; |
f7d0fe02 KW |
558 | |
559 | l2_table = NULL; | |
560 | l1_table = NULL; | |
561 | l1_size2 = l1_size * sizeof(uint64_t); | |
f7d0fe02 | 562 | if (l1_table_offset != s->l1_table_offset) { |
702ef63f KW |
563 | if (l1_size2 != 0) { |
564 | l1_table = qemu_mallocz(align_offset(l1_size2, 512)); | |
565 | } else { | |
566 | l1_table = NULL; | |
567 | } | |
f7d0fe02 KW |
568 | l1_allocated = 1; |
569 | if (bdrv_pread(s->hd, l1_table_offset, | |
570 | l1_table, l1_size2) != l1_size2) | |
571 | goto fail; | |
572 | for(i = 0;i < l1_size; i++) | |
573 | be64_to_cpus(&l1_table[i]); | |
574 | } else { | |
575 | assert(l1_size == s->l1_size); | |
576 | l1_table = s->l1_table; | |
577 | l1_allocated = 0; | |
578 | } | |
579 | ||
580 | l2_size = s->l2_size * sizeof(uint64_t); | |
581 | l2_table = qemu_malloc(l2_size); | |
582 | l1_modified = 0; | |
583 | for(i = 0; i < l1_size; i++) { | |
584 | l2_offset = l1_table[i]; | |
585 | if (l2_offset) { | |
586 | old_l2_offset = l2_offset; | |
587 | l2_offset &= ~QCOW_OFLAG_COPIED; | |
588 | l2_modified = 0; | |
589 | if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size) | |
590 | goto fail; | |
591 | for(j = 0; j < s->l2_size; j++) { | |
592 | offset = be64_to_cpu(l2_table[j]); | |
593 | if (offset != 0) { | |
594 | old_offset = offset; | |
595 | offset &= ~QCOW_OFLAG_COPIED; | |
596 | if (offset & QCOW_OFLAG_COMPRESSED) { | |
597 | nb_csectors = ((offset >> s->csize_shift) & | |
598 | s->csize_mask) + 1; | |
db3a964f KW |
599 | if (addend != 0) { |
600 | int ret; | |
601 | ret = update_refcount(bs, | |
602 | (offset & s->cluster_offset_mask) & ~511, | |
603 | nb_csectors * 512, addend); | |
604 | if (ret < 0) { | |
605 | goto fail; | |
606 | } | |
607 | } | |
f7d0fe02 KW |
608 | /* compressed clusters are never modified */ |
609 | refcount = 2; | |
610 | } else { | |
611 | if (addend != 0) { | |
612 | refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend); | |
613 | } else { | |
614 | refcount = get_refcount(bs, offset >> s->cluster_bits); | |
615 | } | |
616 | } | |
617 | ||
618 | if (refcount == 1) { | |
619 | offset |= QCOW_OFLAG_COPIED; | |
620 | } | |
621 | if (offset != old_offset) { | |
622 | l2_table[j] = cpu_to_be64(offset); | |
623 | l2_modified = 1; | |
624 | } | |
625 | } | |
626 | } | |
627 | if (l2_modified) { | |
628 | if (bdrv_pwrite(s->hd, | |
629 | l2_offset, l2_table, l2_size) != l2_size) | |
630 | goto fail; | |
631 | } | |
632 | ||
633 | if (addend != 0) { | |
634 | refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend); | |
635 | } else { | |
636 | refcount = get_refcount(bs, l2_offset >> s->cluster_bits); | |
637 | } | |
638 | if (refcount == 1) { | |
639 | l2_offset |= QCOW_OFLAG_COPIED; | |
640 | } | |
641 | if (l2_offset != old_l2_offset) { | |
642 | l1_table[i] = l2_offset; | |
643 | l1_modified = 1; | |
644 | } | |
645 | } | |
646 | } | |
647 | if (l1_modified) { | |
648 | for(i = 0; i < l1_size; i++) | |
649 | cpu_to_be64s(&l1_table[i]); | |
650 | if (bdrv_pwrite(s->hd, l1_table_offset, l1_table, | |
651 | l1_size2) != l1_size2) | |
652 | goto fail; | |
653 | for(i = 0; i < l1_size; i++) | |
654 | be64_to_cpus(&l1_table[i]); | |
655 | } | |
656 | if (l1_allocated) | |
657 | qemu_free(l1_table); | |
658 | qemu_free(l2_table); | |
3b88e52b KW |
659 | cache_refcount_updates = 0; |
660 | write_refcount_block(s); | |
f7d0fe02 KW |
661 | return 0; |
662 | fail: | |
663 | if (l1_allocated) | |
664 | qemu_free(l1_table); | |
665 | qemu_free(l2_table); | |
3b88e52b KW |
666 | cache_refcount_updates = 0; |
667 | write_refcount_block(s); | |
f7d0fe02 KW |
668 | return -EIO; |
669 | } | |
670 | ||
671 | ||
672 | ||
673 | ||
674 | /*********************************************************/ | |
675 | /* refcount checking functions */ | |
676 | ||
677 | ||
678 | ||
679 | /* | |
680 | * Increases the refcount for a range of clusters in a given refcount table. | |
681 | * This is used to construct a temporary refcount table out of L1 and L2 tables | |
682 | * which can be compared the the refcount table saved in the image. | |
683 | * | |
684 | * Returns the number of errors in the image that were found | |
685 | */ | |
686 | static int inc_refcounts(BlockDriverState *bs, | |
687 | uint16_t *refcount_table, | |
688 | int refcount_table_size, | |
689 | int64_t offset, int64_t size) | |
690 | { | |
691 | BDRVQcowState *s = bs->opaque; | |
692 | int64_t start, last, cluster_offset; | |
693 | int k; | |
694 | int errors = 0; | |
695 | ||
696 | if (size <= 0) | |
697 | return 0; | |
698 | ||
699 | start = offset & ~(s->cluster_size - 1); | |
700 | last = (offset + size - 1) & ~(s->cluster_size - 1); | |
701 | for(cluster_offset = start; cluster_offset <= last; | |
702 | cluster_offset += s->cluster_size) { | |
703 | k = cluster_offset >> s->cluster_bits; | |
704 | if (k < 0 || k >= refcount_table_size) { | |
705 | fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", | |
706 | cluster_offset); | |
707 | errors++; | |
708 | } else { | |
709 | if (++refcount_table[k] == 0) { | |
710 | fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 | |
711 | "\n", cluster_offset); | |
712 | errors++; | |
713 | } | |
714 | } | |
715 | } | |
716 | ||
717 | return errors; | |
718 | } | |
719 | ||
720 | /* | |
721 | * Increases the refcount in the given refcount table for the all clusters | |
722 | * referenced in the L2 table. While doing so, performs some checks on L2 | |
723 | * entries. | |
724 | * | |
725 | * Returns the number of errors found by the checks or -errno if an internal | |
726 | * error occurred. | |
727 | */ | |
728 | static int check_refcounts_l2(BlockDriverState *bs, | |
729 | uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset, | |
730 | int check_copied) | |
731 | { | |
732 | BDRVQcowState *s = bs->opaque; | |
733 | uint64_t *l2_table, offset; | |
734 | int i, l2_size, nb_csectors, refcount; | |
735 | int errors = 0; | |
736 | ||
737 | /* Read L2 table from disk */ | |
738 | l2_size = s->l2_size * sizeof(uint64_t); | |
739 | l2_table = qemu_malloc(l2_size); | |
740 | ||
741 | if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size) | |
742 | goto fail; | |
743 | ||
744 | /* Do the actual checks */ | |
745 | for(i = 0; i < s->l2_size; i++) { | |
746 | offset = be64_to_cpu(l2_table[i]); | |
747 | if (offset != 0) { | |
748 | if (offset & QCOW_OFLAG_COMPRESSED) { | |
749 | /* Compressed clusters don't have QCOW_OFLAG_COPIED */ | |
750 | if (offset & QCOW_OFLAG_COPIED) { | |
751 | fprintf(stderr, "ERROR: cluster %" PRId64 ": " | |
752 | "copied flag must never be set for compressed " | |
753 | "clusters\n", offset >> s->cluster_bits); | |
754 | offset &= ~QCOW_OFLAG_COPIED; | |
755 | errors++; | |
756 | } | |
757 | ||
758 | /* Mark cluster as used */ | |
759 | nb_csectors = ((offset >> s->csize_shift) & | |
760 | s->csize_mask) + 1; | |
761 | offset &= s->cluster_offset_mask; | |
762 | errors += inc_refcounts(bs, refcount_table, | |
763 | refcount_table_size, | |
764 | offset & ~511, nb_csectors * 512); | |
765 | } else { | |
766 | /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ | |
767 | if (check_copied) { | |
768 | uint64_t entry = offset; | |
769 | offset &= ~QCOW_OFLAG_COPIED; | |
770 | refcount = get_refcount(bs, offset >> s->cluster_bits); | |
771 | if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) { | |
772 | fprintf(stderr, "ERROR OFLAG_COPIED: offset=%" | |
773 | PRIx64 " refcount=%d\n", entry, refcount); | |
774 | errors++; | |
775 | } | |
776 | } | |
777 | ||
778 | /* Mark cluster as used */ | |
779 | offset &= ~QCOW_OFLAG_COPIED; | |
780 | errors += inc_refcounts(bs, refcount_table, | |
781 | refcount_table_size, | |
782 | offset, s->cluster_size); | |
783 | ||
784 | /* Correct offsets are cluster aligned */ | |
785 | if (offset & (s->cluster_size - 1)) { | |
786 | fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " | |
787 | "properly aligned; L2 entry corrupted.\n", offset); | |
788 | errors++; | |
789 | } | |
790 | } | |
791 | } | |
792 | } | |
793 | ||
794 | qemu_free(l2_table); | |
795 | return errors; | |
796 | ||
797 | fail: | |
798 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); | |
799 | qemu_free(l2_table); | |
800 | return -EIO; | |
801 | } | |
802 | ||
803 | /* | |
804 | * Increases the refcount for the L1 table, its L2 tables and all referenced | |
805 | * clusters in the given refcount table. While doing so, performs some checks | |
806 | * on L1 and L2 entries. | |
807 | * | |
808 | * Returns the number of errors found by the checks or -errno if an internal | |
809 | * error occurred. | |
810 | */ | |
811 | static int check_refcounts_l1(BlockDriverState *bs, | |
812 | uint16_t *refcount_table, | |
813 | int refcount_table_size, | |
814 | int64_t l1_table_offset, int l1_size, | |
815 | int check_copied) | |
816 | { | |
817 | BDRVQcowState *s = bs->opaque; | |
818 | uint64_t *l1_table, l2_offset, l1_size2; | |
819 | int i, refcount, ret; | |
820 | int errors = 0; | |
821 | ||
822 | l1_size2 = l1_size * sizeof(uint64_t); | |
823 | ||
824 | /* Mark L1 table as used */ | |
825 | errors += inc_refcounts(bs, refcount_table, refcount_table_size, | |
826 | l1_table_offset, l1_size2); | |
827 | ||
828 | /* Read L1 table entries from disk */ | |
702ef63f KW |
829 | if (l1_size2 == 0) { |
830 | l1_table = NULL; | |
831 | } else { | |
832 | l1_table = qemu_malloc(l1_size2); | |
833 | if (bdrv_pread(s->hd, l1_table_offset, | |
834 | l1_table, l1_size2) != l1_size2) | |
835 | goto fail; | |
836 | for(i = 0;i < l1_size; i++) | |
837 | be64_to_cpus(&l1_table[i]); | |
838 | } | |
f7d0fe02 KW |
839 | |
840 | /* Do the actual checks */ | |
841 | for(i = 0; i < l1_size; i++) { | |
842 | l2_offset = l1_table[i]; | |
843 | if (l2_offset) { | |
844 | /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ | |
845 | if (check_copied) { | |
846 | refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) | |
847 | >> s->cluster_bits); | |
848 | if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { | |
849 | fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64 | |
850 | " refcount=%d\n", l2_offset, refcount); | |
851 | errors++; | |
852 | } | |
853 | } | |
854 | ||
855 | /* Mark L2 table as used */ | |
856 | l2_offset &= ~QCOW_OFLAG_COPIED; | |
857 | errors += inc_refcounts(bs, refcount_table, | |
858 | refcount_table_size, | |
859 | l2_offset, | |
860 | s->cluster_size); | |
861 | ||
862 | /* L2 tables are cluster aligned */ | |
863 | if (l2_offset & (s->cluster_size - 1)) { | |
864 | fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " | |
865 | "cluster aligned; L1 entry corrupted\n", l2_offset); | |
866 | errors++; | |
867 | } | |
868 | ||
869 | /* Process and check L2 entries */ | |
870 | ret = check_refcounts_l2(bs, refcount_table, refcount_table_size, | |
871 | l2_offset, check_copied); | |
872 | if (ret < 0) { | |
873 | goto fail; | |
874 | } | |
875 | errors += ret; | |
876 | } | |
877 | } | |
878 | qemu_free(l1_table); | |
879 | return errors; | |
880 | ||
881 | fail: | |
882 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); | |
883 | qemu_free(l1_table); | |
884 | return -EIO; | |
885 | } | |
886 | ||
887 | /* | |
888 | * Checks an image for refcount consistency. | |
889 | * | |
890 | * Returns 0 if no errors are found, the number of errors in case the image is | |
891 | * detected as corrupted, and -errno when an internal error occured. | |
892 | */ | |
ed6ccf0f | 893 | int qcow2_check_refcounts(BlockDriverState *bs) |
f7d0fe02 KW |
894 | { |
895 | BDRVQcowState *s = bs->opaque; | |
896 | int64_t size; | |
897 | int nb_clusters, refcount1, refcount2, i; | |
898 | QCowSnapshot *sn; | |
899 | uint16_t *refcount_table; | |
900 | int ret, errors = 0; | |
901 | ||
902 | size = bdrv_getlength(s->hd); | |
903 | nb_clusters = size_to_clusters(s, size); | |
904 | refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t)); | |
905 | ||
906 | /* header */ | |
907 | errors += inc_refcounts(bs, refcount_table, nb_clusters, | |
908 | 0, s->cluster_size); | |
909 | ||
910 | /* current L1 table */ | |
911 | ret = check_refcounts_l1(bs, refcount_table, nb_clusters, | |
912 | s->l1_table_offset, s->l1_size, 1); | |
913 | if (ret < 0) { | |
914 | return ret; | |
915 | } | |
916 | errors += ret; | |
917 | ||
918 | /* snapshots */ | |
919 | for(i = 0; i < s->nb_snapshots; i++) { | |
920 | sn = s->snapshots + i; | |
921 | check_refcounts_l1(bs, refcount_table, nb_clusters, | |
922 | sn->l1_table_offset, sn->l1_size, 0); | |
923 | } | |
924 | errors += inc_refcounts(bs, refcount_table, nb_clusters, | |
925 | s->snapshots_offset, s->snapshots_size); | |
926 | ||
927 | /* refcount data */ | |
928 | errors += inc_refcounts(bs, refcount_table, nb_clusters, | |
929 | s->refcount_table_offset, | |
930 | s->refcount_table_size * sizeof(uint64_t)); | |
931 | for(i = 0; i < s->refcount_table_size; i++) { | |
932 | int64_t offset; | |
933 | offset = s->refcount_table[i]; | |
934 | if (offset != 0) { | |
935 | errors += inc_refcounts(bs, refcount_table, nb_clusters, | |
936 | offset, s->cluster_size); | |
937 | } | |
938 | } | |
939 | ||
940 | /* compare ref counts */ | |
941 | for(i = 0; i < nb_clusters; i++) { | |
942 | refcount1 = get_refcount(bs, i); | |
943 | refcount2 = refcount_table[i]; | |
944 | if (refcount1 != refcount2) { | |
945 | fprintf(stderr, "ERROR cluster %d refcount=%d reference=%d\n", | |
946 | i, refcount1, refcount2); | |
947 | errors++; | |
948 | } | |
949 | } | |
950 | ||
951 | qemu_free(refcount_table); | |
952 | ||
953 | return errors; | |
954 | } | |
955 |