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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); | |
92dcb59f | 30 | static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
f7d0fe02 KW |
31 | int64_t offset, int64_t length, |
32 | int addend); | |
33 | ||
3b88e52b KW |
34 | |
35 | static int cache_refcount_updates = 0; | |
36 | ||
66f82cee | 37 | static int write_refcount_block(BlockDriverState *bs) |
3b88e52b | 38 | { |
66f82cee | 39 | BDRVQcowState *s = bs->opaque; |
3b88e52b KW |
40 | size_t size = s->cluster_size; |
41 | ||
42 | if (s->refcount_block_cache_offset == 0) { | |
43 | return 0; | |
44 | } | |
45 | ||
66f82cee KW |
46 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE); |
47 | if (bdrv_pwrite(bs->file, s->refcount_block_cache_offset, | |
3b88e52b KW |
48 | s->refcount_block_cache, size) != size) |
49 | { | |
50 | return -EIO; | |
51 | } | |
52 | ||
53 | return 0; | |
54 | } | |
55 | ||
f7d0fe02 KW |
56 | /*********************************************************/ |
57 | /* refcount handling */ | |
58 | ||
ed6ccf0f | 59 | int qcow2_refcount_init(BlockDriverState *bs) |
f7d0fe02 KW |
60 | { |
61 | BDRVQcowState *s = bs->opaque; | |
62 | int ret, refcount_table_size2, i; | |
63 | ||
64 | s->refcount_block_cache = qemu_malloc(s->cluster_size); | |
65 | refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); | |
66 | s->refcount_table = qemu_malloc(refcount_table_size2); | |
67 | if (s->refcount_table_size > 0) { | |
66f82cee KW |
68 | BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD); |
69 | ret = bdrv_pread(bs->file, s->refcount_table_offset, | |
f7d0fe02 KW |
70 | s->refcount_table, refcount_table_size2); |
71 | if (ret != refcount_table_size2) | |
72 | goto fail; | |
73 | for(i = 0; i < s->refcount_table_size; i++) | |
74 | be64_to_cpus(&s->refcount_table[i]); | |
75 | } | |
76 | return 0; | |
77 | fail: | |
78 | return -ENOMEM; | |
79 | } | |
80 | ||
ed6ccf0f | 81 | void qcow2_refcount_close(BlockDriverState *bs) |
f7d0fe02 KW |
82 | { |
83 | BDRVQcowState *s = bs->opaque; | |
84 | qemu_free(s->refcount_block_cache); | |
85 | qemu_free(s->refcount_table); | |
86 | } | |
87 | ||
88 | ||
89 | static int load_refcount_block(BlockDriverState *bs, | |
90 | int64_t refcount_block_offset) | |
91 | { | |
92 | BDRVQcowState *s = bs->opaque; | |
93 | int ret; | |
3b88e52b KW |
94 | |
95 | if (cache_refcount_updates) { | |
66f82cee | 96 | write_refcount_block(bs); |
3b88e52b KW |
97 | } |
98 | ||
66f82cee KW |
99 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD); |
100 | ret = bdrv_pread(bs->file, refcount_block_offset, s->refcount_block_cache, | |
f7d0fe02 KW |
101 | s->cluster_size); |
102 | if (ret != s->cluster_size) | |
103 | return -EIO; | |
104 | s->refcount_block_cache_offset = refcount_block_offset; | |
105 | return 0; | |
106 | } | |
107 | ||
108 | static int get_refcount(BlockDriverState *bs, int64_t cluster_index) | |
109 | { | |
110 | BDRVQcowState *s = bs->opaque; | |
111 | int refcount_table_index, block_index; | |
112 | int64_t refcount_block_offset; | |
113 | ||
114 | refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
115 | if (refcount_table_index >= s->refcount_table_size) | |
116 | return 0; | |
117 | refcount_block_offset = s->refcount_table[refcount_table_index]; | |
118 | if (!refcount_block_offset) | |
119 | return 0; | |
120 | if (refcount_block_offset != s->refcount_block_cache_offset) { | |
121 | /* better than nothing: return allocated if read error */ | |
122 | if (load_refcount_block(bs, refcount_block_offset) < 0) | |
123 | return 1; | |
124 | } | |
125 | block_index = cluster_index & | |
126 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
127 | return be16_to_cpu(s->refcount_block_cache[block_index]); | |
128 | } | |
129 | ||
05121aed KW |
130 | /* |
131 | * Rounds the refcount table size up to avoid growing the table for each single | |
132 | * refcount block that is allocated. | |
133 | */ | |
134 | static unsigned int next_refcount_table_size(BDRVQcowState *s, | |
135 | unsigned int min_size) | |
136 | { | |
137 | unsigned int min_clusters = (min_size >> (s->cluster_bits - 3)) + 1; | |
138 | unsigned int refcount_table_clusters = | |
139 | MAX(1, s->refcount_table_size >> (s->cluster_bits - 3)); | |
140 | ||
141 | while (min_clusters > refcount_table_clusters) { | |
142 | refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; | |
143 | } | |
144 | ||
145 | return refcount_table_clusters << (s->cluster_bits - 3); | |
146 | } | |
147 | ||
92dcb59f KW |
148 | |
149 | /* Checks if two offsets are described by the same refcount block */ | |
150 | static int in_same_refcount_block(BDRVQcowState *s, uint64_t offset_a, | |
151 | uint64_t offset_b) | |
152 | { | |
153 | uint64_t block_a = offset_a >> (2 * s->cluster_bits - REFCOUNT_SHIFT); | |
154 | uint64_t block_b = offset_b >> (2 * s->cluster_bits - REFCOUNT_SHIFT); | |
155 | ||
156 | return (block_a == block_b); | |
157 | } | |
158 | ||
159 | /* | |
160 | * Loads a refcount block. If it doesn't exist yet, it is allocated first | |
161 | * (including growing the refcount table if needed). | |
162 | * | |
163 | * Returns the offset of the refcount block on success or -errno in error case | |
164 | */ | |
165 | static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index) | |
f7d0fe02 KW |
166 | { |
167 | BDRVQcowState *s = bs->opaque; | |
92dcb59f KW |
168 | unsigned int refcount_table_index; |
169 | int ret; | |
170 | ||
66f82cee | 171 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); |
8252278a | 172 | |
92dcb59f KW |
173 | /* Find the refcount block for the given cluster */ |
174 | refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
175 | ||
176 | if (refcount_table_index < s->refcount_table_size) { | |
177 | ||
178 | uint64_t refcount_block_offset = | |
179 | s->refcount_table[refcount_table_index]; | |
180 | ||
181 | /* If it's already there, we're done */ | |
182 | if (refcount_block_offset) { | |
183 | if (refcount_block_offset != s->refcount_block_cache_offset) { | |
184 | ret = load_refcount_block(bs, refcount_block_offset); | |
185 | if (ret < 0) { | |
186 | return ret; | |
187 | } | |
188 | } | |
189 | return refcount_block_offset; | |
190 | } | |
191 | } | |
192 | ||
193 | /* | |
194 | * If we came here, we need to allocate something. Something is at least | |
195 | * a cluster for the new refcount block. It may also include a new refcount | |
196 | * table if the old refcount table is too small. | |
197 | * | |
198 | * Note that allocating clusters here needs some special care: | |
199 | * | |
200 | * - We can't use the normal qcow2_alloc_clusters(), it would try to | |
201 | * increase the refcount and very likely we would end up with an endless | |
202 | * recursion. Instead we must place the refcount blocks in a way that | |
203 | * they can describe them themselves. | |
204 | * | |
205 | * - We need to consider that at this point we are inside update_refcounts | |
206 | * and doing the initial refcount increase. This means that some clusters | |
207 | * have already been allocated by the caller, but their refcount isn't | |
208 | * accurate yet. free_cluster_index tells us where this allocation ends | |
209 | * as long as we don't overwrite it by freeing clusters. | |
210 | * | |
211 | * - alloc_clusters_noref and qcow2_free_clusters may load a different | |
212 | * refcount block into the cache | |
213 | */ | |
214 | ||
215 | if (cache_refcount_updates) { | |
66f82cee | 216 | ret = write_refcount_block(bs); |
92dcb59f KW |
217 | if (ret < 0) { |
218 | return ret; | |
219 | } | |
220 | } | |
221 | ||
222 | /* Allocate the refcount block itself and mark it as used */ | |
223 | uint64_t new_block = alloc_clusters_noref(bs, s->cluster_size); | |
224 | memset(s->refcount_block_cache, 0, s->cluster_size); | |
225 | s->refcount_block_cache_offset = new_block; | |
f7d0fe02 | 226 | |
f7d0fe02 | 227 | #ifdef DEBUG_ALLOC2 |
92dcb59f KW |
228 | fprintf(stderr, "qcow2: Allocate refcount block %d for %" PRIx64 |
229 | " at %" PRIx64 "\n", | |
230 | refcount_table_index, cluster_index << s->cluster_bits, new_block); | |
f7d0fe02 | 231 | #endif |
92dcb59f KW |
232 | |
233 | if (in_same_refcount_block(s, new_block, cluster_index << s->cluster_bits)) { | |
234 | /* The block describes itself, need to update the cache */ | |
235 | int block_index = (new_block >> s->cluster_bits) & | |
236 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
237 | s->refcount_block_cache[block_index] = cpu_to_be16(1); | |
238 | } else { | |
239 | /* Described somewhere else. This can recurse at most twice before we | |
240 | * arrive at a block that describes itself. */ | |
241 | ret = update_refcount(bs, new_block, s->cluster_size, 1); | |
242 | if (ret < 0) { | |
243 | goto fail_block; | |
244 | } | |
245 | } | |
246 | ||
247 | /* Now the new refcount block needs to be written to disk */ | |
66f82cee KW |
248 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE); |
249 | ret = bdrv_pwrite(bs->file, new_block, s->refcount_block_cache, | |
92dcb59f KW |
250 | s->cluster_size); |
251 | if (ret < 0) { | |
252 | goto fail_block; | |
253 | } | |
254 | ||
255 | /* If the refcount table is big enough, just hook the block up there */ | |
256 | if (refcount_table_index < s->refcount_table_size) { | |
257 | uint64_t data64 = cpu_to_be64(new_block); | |
66f82cee KW |
258 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_HOOKUP); |
259 | ret = bdrv_pwrite(bs->file, | |
92dcb59f KW |
260 | s->refcount_table_offset + refcount_table_index * sizeof(uint64_t), |
261 | &data64, sizeof(data64)); | |
262 | if (ret < 0) { | |
263 | goto fail_block; | |
264 | } | |
265 | ||
266 | s->refcount_table[refcount_table_index] = new_block; | |
267 | return new_block; | |
268 | } | |
269 | ||
270 | /* | |
271 | * If we come here, we need to grow the refcount table. Again, a new | |
272 | * refcount table needs some space and we can't simply allocate to avoid | |
273 | * endless recursion. | |
274 | * | |
275 | * Therefore let's grab new refcount blocks at the end of the image, which | |
276 | * will describe themselves and the new refcount table. This way we can | |
277 | * reference them only in the new table and do the switch to the new | |
278 | * refcount table at once without producing an inconsistent state in | |
279 | * between. | |
280 | */ | |
66f82cee | 281 | BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW); |
8252278a | 282 | |
92dcb59f KW |
283 | /* Calculate the number of refcount blocks needed so far */ |
284 | uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT); | |
285 | uint64_t blocks_used = (s->free_cluster_index + | |
286 | refcount_block_clusters - 1) / refcount_block_clusters; | |
287 | ||
288 | /* And now we need at least one block more for the new metadata */ | |
289 | uint64_t table_size = next_refcount_table_size(s, blocks_used + 1); | |
290 | uint64_t last_table_size; | |
291 | uint64_t blocks_clusters; | |
292 | do { | |
293 | uint64_t table_clusters = size_to_clusters(s, table_size); | |
294 | blocks_clusters = 1 + | |
295 | ((table_clusters + refcount_block_clusters - 1) | |
296 | / refcount_block_clusters); | |
297 | uint64_t meta_clusters = table_clusters + blocks_clusters; | |
298 | ||
299 | last_table_size = table_size; | |
300 | table_size = next_refcount_table_size(s, blocks_used + | |
301 | ((meta_clusters + refcount_block_clusters - 1) | |
302 | / refcount_block_clusters)); | |
303 | ||
304 | } while (last_table_size != table_size); | |
305 | ||
306 | #ifdef DEBUG_ALLOC2 | |
307 | fprintf(stderr, "qcow2: Grow refcount table %" PRId32 " => %" PRId64 "\n", | |
308 | s->refcount_table_size, table_size); | |
309 | #endif | |
310 | ||
311 | /* Create the new refcount table and blocks */ | |
312 | uint64_t meta_offset = (blocks_used * refcount_block_clusters) * | |
313 | s->cluster_size; | |
314 | uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size; | |
315 | uint16_t *new_blocks = qemu_mallocz(blocks_clusters * s->cluster_size); | |
316 | uint64_t *new_table = qemu_mallocz(table_size * sizeof(uint64_t)); | |
317 | ||
318 | assert(meta_offset >= (s->free_cluster_index * s->cluster_size)); | |
319 | ||
320 | /* Fill the new refcount table */ | |
f7d0fe02 | 321 | memcpy(new_table, s->refcount_table, |
92dcb59f KW |
322 | s->refcount_table_size * sizeof(uint64_t)); |
323 | new_table[refcount_table_index] = new_block; | |
324 | ||
325 | int i; | |
326 | for (i = 0; i < blocks_clusters; i++) { | |
327 | new_table[blocks_used + i] = meta_offset + (i * s->cluster_size); | |
328 | } | |
329 | ||
330 | /* Fill the refcount blocks */ | |
331 | uint64_t table_clusters = size_to_clusters(s, table_size * sizeof(uint64_t)); | |
332 | int block = 0; | |
333 | for (i = 0; i < table_clusters + blocks_clusters; i++) { | |
334 | new_blocks[block++] = cpu_to_be16(1); | |
335 | } | |
336 | ||
337 | /* Write refcount blocks to disk */ | |
66f82cee KW |
338 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS); |
339 | ret = bdrv_pwrite(bs->file, meta_offset, new_blocks, | |
92dcb59f KW |
340 | blocks_clusters * s->cluster_size); |
341 | qemu_free(new_blocks); | |
342 | if (ret < 0) { | |
343 | goto fail_table; | |
344 | } | |
345 | ||
346 | /* Write refcount table to disk */ | |
347 | for(i = 0; i < table_size; i++) { | |
348 | cpu_to_be64s(&new_table[i]); | |
349 | } | |
350 | ||
66f82cee KW |
351 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE); |
352 | ret = bdrv_pwrite(bs->file, table_offset, new_table, | |
92dcb59f KW |
353 | table_size * sizeof(uint64_t)); |
354 | if (ret < 0) { | |
355 | goto fail_table; | |
356 | } | |
357 | ||
358 | for(i = 0; i < table_size; i++) { | |
f7d0fe02 | 359 | cpu_to_be64s(&new_table[i]); |
92dcb59f | 360 | } |
f7d0fe02 | 361 | |
92dcb59f KW |
362 | /* Hook up the new refcount table in the qcow2 header */ |
363 | uint8_t data[12]; | |
f7d0fe02 | 364 | cpu_to_be64w((uint64_t*)data, table_offset); |
92dcb59f | 365 | cpu_to_be32w((uint32_t*)(data + 8), table_clusters); |
66f82cee KW |
366 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE); |
367 | ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, refcount_table_offset), | |
92dcb59f KW |
368 | data, sizeof(data)); |
369 | if (ret < 0) { | |
370 | goto fail_table; | |
f2b7c8b3 KW |
371 | } |
372 | ||
92dcb59f KW |
373 | /* And switch it in memory */ |
374 | uint64_t old_table_offset = s->refcount_table_offset; | |
375 | uint64_t old_table_size = s->refcount_table_size; | |
376 | ||
f7d0fe02 | 377 | qemu_free(s->refcount_table); |
f7d0fe02 | 378 | s->refcount_table = new_table; |
92dcb59f | 379 | s->refcount_table_size = table_size; |
f7d0fe02 KW |
380 | s->refcount_table_offset = table_offset; |
381 | ||
92dcb59f KW |
382 | /* Free old table. Remember, we must not change free_cluster_index */ |
383 | uint64_t old_free_cluster_index = s->free_cluster_index; | |
ed6ccf0f | 384 | qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t)); |
92dcb59f | 385 | s->free_cluster_index = old_free_cluster_index; |
f7d0fe02 | 386 | |
92dcb59f KW |
387 | ret = load_refcount_block(bs, new_block); |
388 | if (ret < 0) { | |
389 | goto fail_block; | |
f7d0fe02 KW |
390 | } |
391 | ||
92dcb59f | 392 | return new_block; |
f7d0fe02 | 393 | |
92dcb59f KW |
394 | fail_table: |
395 | qemu_free(new_table); | |
396 | fail_block: | |
397 | s->refcount_block_cache_offset = 0; | |
398 | return ret; | |
f7d0fe02 KW |
399 | } |
400 | ||
9923e05e | 401 | #define REFCOUNTS_PER_SECTOR (512 >> REFCOUNT_SHIFT) |
66f82cee | 402 | static int write_refcount_block_entries(BlockDriverState *bs, |
9923e05e KW |
403 | int64_t refcount_block_offset, int first_index, int last_index) |
404 | { | |
66f82cee | 405 | BDRVQcowState *s = bs->opaque; |
9923e05e KW |
406 | size_t size; |
407 | ||
3b88e52b KW |
408 | if (cache_refcount_updates) { |
409 | return 0; | |
410 | } | |
411 | ||
9923e05e KW |
412 | first_index &= ~(REFCOUNTS_PER_SECTOR - 1); |
413 | last_index = (last_index + REFCOUNTS_PER_SECTOR) | |
414 | & ~(REFCOUNTS_PER_SECTOR - 1); | |
415 | ||
416 | size = (last_index - first_index) << REFCOUNT_SHIFT; | |
66f82cee KW |
417 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE_PART); |
418 | if (bdrv_pwrite(bs->file, | |
9923e05e KW |
419 | refcount_block_offset + (first_index << REFCOUNT_SHIFT), |
420 | &s->refcount_block_cache[first_index], size) != size) | |
421 | { | |
422 | return -EIO; | |
423 | } | |
424 | ||
425 | return 0; | |
426 | } | |
427 | ||
f7d0fe02 | 428 | /* XXX: cache several refcount block clusters ? */ |
db3a964f KW |
429 | static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
430 | int64_t offset, int64_t length, int addend) | |
f7d0fe02 KW |
431 | { |
432 | BDRVQcowState *s = bs->opaque; | |
433 | int64_t start, last, cluster_offset; | |
434 | int64_t refcount_block_offset = 0; | |
435 | int64_t table_index = -1, old_table_index; | |
436 | int first_index = -1, last_index = -1; | |
09508d13 | 437 | int ret; |
f7d0fe02 KW |
438 | |
439 | #ifdef DEBUG_ALLOC2 | |
0bf9e31a | 440 | printf("update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", |
f7d0fe02 KW |
441 | offset, length, addend); |
442 | #endif | |
7322afe7 | 443 | if (length < 0) { |
f7d0fe02 | 444 | return -EINVAL; |
7322afe7 KW |
445 | } else if (length == 0) { |
446 | return 0; | |
447 | } | |
448 | ||
f7d0fe02 KW |
449 | start = offset & ~(s->cluster_size - 1); |
450 | last = (offset + length - 1) & ~(s->cluster_size - 1); | |
451 | for(cluster_offset = start; cluster_offset <= last; | |
452 | cluster_offset += s->cluster_size) | |
453 | { | |
454 | int block_index, refcount; | |
455 | int64_t cluster_index = cluster_offset >> s->cluster_bits; | |
09508d13 | 456 | int64_t new_block; |
f7d0fe02 KW |
457 | |
458 | /* Only write refcount block to disk when we are done with it */ | |
459 | old_table_index = table_index; | |
460 | table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
461 | if ((old_table_index >= 0) && (table_index != old_table_index)) { | |
9923e05e | 462 | |
66f82cee | 463 | if (write_refcount_block_entries(bs, refcount_block_offset, |
9923e05e | 464 | first_index, last_index) < 0) |
f7d0fe02 KW |
465 | { |
466 | return -EIO; | |
467 | } | |
468 | ||
469 | first_index = -1; | |
470 | last_index = -1; | |
471 | } | |
472 | ||
473 | /* Load the refcount block and allocate it if needed */ | |
09508d13 KW |
474 | new_block = alloc_refcount_block(bs, cluster_index); |
475 | if (new_block < 0) { | |
476 | ret = new_block; | |
477 | goto fail; | |
f7d0fe02 | 478 | } |
09508d13 | 479 | refcount_block_offset = new_block; |
f7d0fe02 KW |
480 | |
481 | /* we can update the count and save it */ | |
482 | block_index = cluster_index & | |
483 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
484 | if (first_index == -1 || block_index < first_index) { | |
485 | first_index = block_index; | |
486 | } | |
487 | if (block_index > last_index) { | |
488 | last_index = block_index; | |
489 | } | |
490 | ||
491 | refcount = be16_to_cpu(s->refcount_block_cache[block_index]); | |
492 | refcount += addend; | |
09508d13 KW |
493 | if (refcount < 0 || refcount > 0xffff) { |
494 | ret = -EINVAL; | |
495 | goto fail; | |
496 | } | |
f7d0fe02 KW |
497 | if (refcount == 0 && cluster_index < s->free_cluster_index) { |
498 | s->free_cluster_index = cluster_index; | |
499 | } | |
500 | s->refcount_block_cache[block_index] = cpu_to_be16(refcount); | |
501 | } | |
502 | ||
09508d13 KW |
503 | ret = 0; |
504 | fail: | |
505 | ||
f7d0fe02 KW |
506 | /* Write last changed block to disk */ |
507 | if (refcount_block_offset != 0) { | |
66f82cee | 508 | if (write_refcount_block_entries(bs, refcount_block_offset, |
9923e05e | 509 | first_index, last_index) < 0) |
f7d0fe02 | 510 | { |
09508d13 | 511 | return ret < 0 ? ret : -EIO; |
f7d0fe02 KW |
512 | } |
513 | } | |
514 | ||
09508d13 KW |
515 | /* |
516 | * Try do undo any updates if an error is returned (This may succeed in | |
517 | * some cases like ENOSPC for allocating a new refcount block) | |
518 | */ | |
519 | if (ret < 0) { | |
520 | int dummy; | |
521 | dummy = update_refcount(bs, offset, cluster_offset - offset, -addend); | |
522 | } | |
523 | ||
524 | return ret; | |
f7d0fe02 KW |
525 | } |
526 | ||
527 | /* addend must be 1 or -1 */ | |
528 | static int update_cluster_refcount(BlockDriverState *bs, | |
529 | int64_t cluster_index, | |
530 | int addend) | |
531 | { | |
532 | BDRVQcowState *s = bs->opaque; | |
533 | int ret; | |
534 | ||
535 | ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend); | |
536 | if (ret < 0) { | |
537 | return ret; | |
538 | } | |
539 | ||
540 | return get_refcount(bs, cluster_index); | |
541 | } | |
542 | ||
543 | ||
544 | ||
545 | /*********************************************************/ | |
546 | /* cluster allocation functions */ | |
547 | ||
548 | ||
549 | ||
550 | /* return < 0 if error */ | |
551 | static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size) | |
552 | { | |
553 | BDRVQcowState *s = bs->opaque; | |
554 | int i, nb_clusters; | |
555 | ||
556 | nb_clusters = size_to_clusters(s, size); | |
557 | retry: | |
558 | for(i = 0; i < nb_clusters; i++) { | |
508e0893 SH |
559 | int64_t next_cluster_index = s->free_cluster_index++; |
560 | if (get_refcount(bs, next_cluster_index) != 0) | |
f7d0fe02 KW |
561 | goto retry; |
562 | } | |
563 | #ifdef DEBUG_ALLOC2 | |
0bf9e31a | 564 | printf("alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n", |
f7d0fe02 KW |
565 | size, |
566 | (s->free_cluster_index - nb_clusters) << s->cluster_bits); | |
567 | #endif | |
568 | return (s->free_cluster_index - nb_clusters) << s->cluster_bits; | |
569 | } | |
570 | ||
ed6ccf0f | 571 | int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size) |
f7d0fe02 KW |
572 | { |
573 | int64_t offset; | |
db3a964f | 574 | int ret; |
f7d0fe02 | 575 | |
66f82cee | 576 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); |
f7d0fe02 | 577 | offset = alloc_clusters_noref(bs, size); |
db3a964f KW |
578 | ret = update_refcount(bs, offset, size, 1); |
579 | if (ret < 0) { | |
580 | return ret; | |
581 | } | |
f7d0fe02 KW |
582 | return offset; |
583 | } | |
584 | ||
585 | /* only used to allocate compressed sectors. We try to allocate | |
586 | contiguous sectors. size must be <= cluster_size */ | |
ed6ccf0f | 587 | int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) |
f7d0fe02 KW |
588 | { |
589 | BDRVQcowState *s = bs->opaque; | |
590 | int64_t offset, cluster_offset; | |
591 | int free_in_cluster; | |
592 | ||
66f82cee | 593 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); |
f7d0fe02 KW |
594 | assert(size > 0 && size <= s->cluster_size); |
595 | if (s->free_byte_offset == 0) { | |
ed6ccf0f | 596 | s->free_byte_offset = qcow2_alloc_clusters(bs, s->cluster_size); |
5d757b56 KW |
597 | if (s->free_byte_offset < 0) { |
598 | return s->free_byte_offset; | |
599 | } | |
f7d0fe02 KW |
600 | } |
601 | redo: | |
602 | free_in_cluster = s->cluster_size - | |
603 | (s->free_byte_offset & (s->cluster_size - 1)); | |
604 | if (size <= free_in_cluster) { | |
605 | /* enough space in current cluster */ | |
606 | offset = s->free_byte_offset; | |
607 | s->free_byte_offset += size; | |
608 | free_in_cluster -= size; | |
609 | if (free_in_cluster == 0) | |
610 | s->free_byte_offset = 0; | |
611 | if ((offset & (s->cluster_size - 1)) != 0) | |
612 | update_cluster_refcount(bs, offset >> s->cluster_bits, 1); | |
613 | } else { | |
ed6ccf0f | 614 | offset = qcow2_alloc_clusters(bs, s->cluster_size); |
5d757b56 KW |
615 | if (offset < 0) { |
616 | return offset; | |
617 | } | |
f7d0fe02 KW |
618 | cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1); |
619 | if ((cluster_offset + s->cluster_size) == offset) { | |
620 | /* we are lucky: contiguous data */ | |
621 | offset = s->free_byte_offset; | |
622 | update_cluster_refcount(bs, offset >> s->cluster_bits, 1); | |
623 | s->free_byte_offset += size; | |
624 | } else { | |
625 | s->free_byte_offset = offset; | |
626 | goto redo; | |
627 | } | |
628 | } | |
629 | return offset; | |
630 | } | |
631 | ||
ed6ccf0f | 632 | void qcow2_free_clusters(BlockDriverState *bs, |
f7d0fe02 KW |
633 | int64_t offset, int64_t size) |
634 | { | |
db3a964f KW |
635 | int ret; |
636 | ||
66f82cee | 637 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE); |
db3a964f KW |
638 | ret = update_refcount(bs, offset, size, -1); |
639 | if (ret < 0) { | |
640 | fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret)); | |
641 | abort(); | |
642 | } | |
f7d0fe02 KW |
643 | } |
644 | ||
45aba42f KW |
645 | /* |
646 | * free_any_clusters | |
647 | * | |
648 | * free clusters according to its type: compressed or not | |
649 | * | |
650 | */ | |
651 | ||
ed6ccf0f | 652 | void qcow2_free_any_clusters(BlockDriverState *bs, |
45aba42f KW |
653 | uint64_t cluster_offset, int nb_clusters) |
654 | { | |
655 | BDRVQcowState *s = bs->opaque; | |
656 | ||
657 | /* free the cluster */ | |
658 | ||
659 | if (cluster_offset & QCOW_OFLAG_COMPRESSED) { | |
660 | int nb_csectors; | |
661 | nb_csectors = ((cluster_offset >> s->csize_shift) & | |
662 | s->csize_mask) + 1; | |
ed6ccf0f KW |
663 | qcow2_free_clusters(bs, |
664 | (cluster_offset & s->cluster_offset_mask) & ~511, | |
665 | nb_csectors * 512); | |
45aba42f KW |
666 | return; |
667 | } | |
668 | ||
ed6ccf0f | 669 | qcow2_free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits); |
45aba42f KW |
670 | |
671 | return; | |
672 | } | |
673 | ||
f7d0fe02 KW |
674 | |
675 | ||
676 | /*********************************************************/ | |
677 | /* snapshots and image creation */ | |
678 | ||
679 | ||
680 | ||
ed6ccf0f KW |
681 | void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset, |
682 | int64_t size) | |
f7d0fe02 KW |
683 | { |
684 | int refcount; | |
685 | int64_t start, last, cluster_offset; | |
686 | uint16_t *p; | |
687 | ||
688 | start = offset & ~(s->cluster_size - 1); | |
689 | last = (offset + size - 1) & ~(s->cluster_size - 1); | |
690 | for(cluster_offset = start; cluster_offset <= last; | |
691 | cluster_offset += s->cluster_size) { | |
692 | p = &s->refcount_block[cluster_offset >> s->cluster_bits]; | |
693 | refcount = be16_to_cpu(*p); | |
694 | refcount++; | |
695 | *p = cpu_to_be16(refcount); | |
696 | } | |
697 | } | |
698 | ||
699 | /* update the refcounts of snapshots and the copied flag */ | |
ed6ccf0f KW |
700 | int qcow2_update_snapshot_refcount(BlockDriverState *bs, |
701 | int64_t l1_table_offset, int l1_size, int addend) | |
f7d0fe02 KW |
702 | { |
703 | BDRVQcowState *s = bs->opaque; | |
704 | uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; | |
705 | int64_t old_offset, old_l2_offset; | |
706 | int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount; | |
707 | ||
ed6ccf0f | 708 | qcow2_l2_cache_reset(bs); |
3b88e52b | 709 | cache_refcount_updates = 1; |
f7d0fe02 KW |
710 | |
711 | l2_table = NULL; | |
712 | l1_table = NULL; | |
713 | l1_size2 = l1_size * sizeof(uint64_t); | |
f7d0fe02 | 714 | if (l1_table_offset != s->l1_table_offset) { |
702ef63f KW |
715 | if (l1_size2 != 0) { |
716 | l1_table = qemu_mallocz(align_offset(l1_size2, 512)); | |
717 | } else { | |
718 | l1_table = NULL; | |
719 | } | |
f7d0fe02 | 720 | l1_allocated = 1; |
66f82cee | 721 | if (bdrv_pread(bs->file, l1_table_offset, |
f7d0fe02 KW |
722 | l1_table, l1_size2) != l1_size2) |
723 | goto fail; | |
724 | for(i = 0;i < l1_size; i++) | |
725 | be64_to_cpus(&l1_table[i]); | |
726 | } else { | |
727 | assert(l1_size == s->l1_size); | |
728 | l1_table = s->l1_table; | |
729 | l1_allocated = 0; | |
730 | } | |
731 | ||
732 | l2_size = s->l2_size * sizeof(uint64_t); | |
733 | l2_table = qemu_malloc(l2_size); | |
734 | l1_modified = 0; | |
735 | for(i = 0; i < l1_size; i++) { | |
736 | l2_offset = l1_table[i]; | |
737 | if (l2_offset) { | |
738 | old_l2_offset = l2_offset; | |
739 | l2_offset &= ~QCOW_OFLAG_COPIED; | |
740 | l2_modified = 0; | |
66f82cee | 741 | if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size) |
f7d0fe02 KW |
742 | goto fail; |
743 | for(j = 0; j < s->l2_size; j++) { | |
744 | offset = be64_to_cpu(l2_table[j]); | |
745 | if (offset != 0) { | |
746 | old_offset = offset; | |
747 | offset &= ~QCOW_OFLAG_COPIED; | |
748 | if (offset & QCOW_OFLAG_COMPRESSED) { | |
749 | nb_csectors = ((offset >> s->csize_shift) & | |
750 | s->csize_mask) + 1; | |
db3a964f KW |
751 | if (addend != 0) { |
752 | int ret; | |
753 | ret = update_refcount(bs, | |
754 | (offset & s->cluster_offset_mask) & ~511, | |
755 | nb_csectors * 512, addend); | |
756 | if (ret < 0) { | |
757 | goto fail; | |
758 | } | |
759 | } | |
f7d0fe02 KW |
760 | /* compressed clusters are never modified */ |
761 | refcount = 2; | |
762 | } else { | |
763 | if (addend != 0) { | |
764 | refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend); | |
765 | } else { | |
766 | refcount = get_refcount(bs, offset >> s->cluster_bits); | |
767 | } | |
768 | } | |
769 | ||
770 | if (refcount == 1) { | |
771 | offset |= QCOW_OFLAG_COPIED; | |
772 | } | |
773 | if (offset != old_offset) { | |
774 | l2_table[j] = cpu_to_be64(offset); | |
775 | l2_modified = 1; | |
776 | } | |
777 | } | |
778 | } | |
779 | if (l2_modified) { | |
66f82cee | 780 | if (bdrv_pwrite(bs->file, |
f7d0fe02 KW |
781 | l2_offset, l2_table, l2_size) != l2_size) |
782 | goto fail; | |
783 | } | |
784 | ||
785 | if (addend != 0) { | |
786 | refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend); | |
787 | } else { | |
788 | refcount = get_refcount(bs, l2_offset >> s->cluster_bits); | |
789 | } | |
790 | if (refcount == 1) { | |
791 | l2_offset |= QCOW_OFLAG_COPIED; | |
792 | } | |
793 | if (l2_offset != old_l2_offset) { | |
794 | l1_table[i] = l2_offset; | |
795 | l1_modified = 1; | |
796 | } | |
797 | } | |
798 | } | |
799 | if (l1_modified) { | |
800 | for(i = 0; i < l1_size; i++) | |
801 | cpu_to_be64s(&l1_table[i]); | |
66f82cee | 802 | if (bdrv_pwrite(bs->file, l1_table_offset, l1_table, |
f7d0fe02 KW |
803 | l1_size2) != l1_size2) |
804 | goto fail; | |
805 | for(i = 0; i < l1_size; i++) | |
806 | be64_to_cpus(&l1_table[i]); | |
807 | } | |
808 | if (l1_allocated) | |
809 | qemu_free(l1_table); | |
810 | qemu_free(l2_table); | |
3b88e52b | 811 | cache_refcount_updates = 0; |
66f82cee | 812 | write_refcount_block(bs); |
f7d0fe02 KW |
813 | return 0; |
814 | fail: | |
815 | if (l1_allocated) | |
816 | qemu_free(l1_table); | |
817 | qemu_free(l2_table); | |
3b88e52b | 818 | cache_refcount_updates = 0; |
66f82cee | 819 | write_refcount_block(bs); |
f7d0fe02 KW |
820 | return -EIO; |
821 | } | |
822 | ||
823 | ||
824 | ||
825 | ||
826 | /*********************************************************/ | |
827 | /* refcount checking functions */ | |
828 | ||
829 | ||
830 | ||
831 | /* | |
832 | * Increases the refcount for a range of clusters in a given refcount table. | |
833 | * This is used to construct a temporary refcount table out of L1 and L2 tables | |
834 | * which can be compared the the refcount table saved in the image. | |
835 | * | |
836 | * Returns the number of errors in the image that were found | |
837 | */ | |
838 | static int inc_refcounts(BlockDriverState *bs, | |
839 | uint16_t *refcount_table, | |
840 | int refcount_table_size, | |
841 | int64_t offset, int64_t size) | |
842 | { | |
843 | BDRVQcowState *s = bs->opaque; | |
844 | int64_t start, last, cluster_offset; | |
845 | int k; | |
846 | int errors = 0; | |
847 | ||
848 | if (size <= 0) | |
849 | return 0; | |
850 | ||
851 | start = offset & ~(s->cluster_size - 1); | |
852 | last = (offset + size - 1) & ~(s->cluster_size - 1); | |
853 | for(cluster_offset = start; cluster_offset <= last; | |
854 | cluster_offset += s->cluster_size) { | |
855 | k = cluster_offset >> s->cluster_bits; | |
856 | if (k < 0 || k >= refcount_table_size) { | |
857 | fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", | |
858 | cluster_offset); | |
859 | errors++; | |
860 | } else { | |
861 | if (++refcount_table[k] == 0) { | |
862 | fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 | |
863 | "\n", cluster_offset); | |
864 | errors++; | |
865 | } | |
866 | } | |
867 | } | |
868 | ||
869 | return errors; | |
870 | } | |
871 | ||
872 | /* | |
873 | * Increases the refcount in the given refcount table for the all clusters | |
874 | * referenced in the L2 table. While doing so, performs some checks on L2 | |
875 | * entries. | |
876 | * | |
877 | * Returns the number of errors found by the checks or -errno if an internal | |
878 | * error occurred. | |
879 | */ | |
880 | static int check_refcounts_l2(BlockDriverState *bs, | |
881 | uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset, | |
882 | int check_copied) | |
883 | { | |
884 | BDRVQcowState *s = bs->opaque; | |
885 | uint64_t *l2_table, offset; | |
886 | int i, l2_size, nb_csectors, refcount; | |
887 | int errors = 0; | |
888 | ||
889 | /* Read L2 table from disk */ | |
890 | l2_size = s->l2_size * sizeof(uint64_t); | |
891 | l2_table = qemu_malloc(l2_size); | |
892 | ||
66f82cee | 893 | if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size) |
f7d0fe02 KW |
894 | goto fail; |
895 | ||
896 | /* Do the actual checks */ | |
897 | for(i = 0; i < s->l2_size; i++) { | |
898 | offset = be64_to_cpu(l2_table[i]); | |
899 | if (offset != 0) { | |
900 | if (offset & QCOW_OFLAG_COMPRESSED) { | |
901 | /* Compressed clusters don't have QCOW_OFLAG_COPIED */ | |
902 | if (offset & QCOW_OFLAG_COPIED) { | |
903 | fprintf(stderr, "ERROR: cluster %" PRId64 ": " | |
904 | "copied flag must never be set for compressed " | |
905 | "clusters\n", offset >> s->cluster_bits); | |
906 | offset &= ~QCOW_OFLAG_COPIED; | |
907 | errors++; | |
908 | } | |
909 | ||
910 | /* Mark cluster as used */ | |
911 | nb_csectors = ((offset >> s->csize_shift) & | |
912 | s->csize_mask) + 1; | |
913 | offset &= s->cluster_offset_mask; | |
914 | errors += inc_refcounts(bs, refcount_table, | |
915 | refcount_table_size, | |
916 | offset & ~511, nb_csectors * 512); | |
917 | } else { | |
918 | /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ | |
919 | if (check_copied) { | |
920 | uint64_t entry = offset; | |
921 | offset &= ~QCOW_OFLAG_COPIED; | |
922 | refcount = get_refcount(bs, offset >> s->cluster_bits); | |
923 | if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) { | |
924 | fprintf(stderr, "ERROR OFLAG_COPIED: offset=%" | |
925 | PRIx64 " refcount=%d\n", entry, refcount); | |
926 | errors++; | |
927 | } | |
928 | } | |
929 | ||
930 | /* Mark cluster as used */ | |
931 | offset &= ~QCOW_OFLAG_COPIED; | |
932 | errors += inc_refcounts(bs, refcount_table, | |
933 | refcount_table_size, | |
934 | offset, s->cluster_size); | |
935 | ||
936 | /* Correct offsets are cluster aligned */ | |
937 | if (offset & (s->cluster_size - 1)) { | |
938 | fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " | |
939 | "properly aligned; L2 entry corrupted.\n", offset); | |
940 | errors++; | |
941 | } | |
942 | } | |
943 | } | |
944 | } | |
945 | ||
946 | qemu_free(l2_table); | |
947 | return errors; | |
948 | ||
949 | fail: | |
950 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); | |
951 | qemu_free(l2_table); | |
952 | return -EIO; | |
953 | } | |
954 | ||
955 | /* | |
956 | * Increases the refcount for the L1 table, its L2 tables and all referenced | |
957 | * clusters in the given refcount table. While doing so, performs some checks | |
958 | * on L1 and L2 entries. | |
959 | * | |
960 | * Returns the number of errors found by the checks or -errno if an internal | |
961 | * error occurred. | |
962 | */ | |
963 | static int check_refcounts_l1(BlockDriverState *bs, | |
964 | uint16_t *refcount_table, | |
965 | int refcount_table_size, | |
966 | int64_t l1_table_offset, int l1_size, | |
967 | int check_copied) | |
968 | { | |
969 | BDRVQcowState *s = bs->opaque; | |
970 | uint64_t *l1_table, l2_offset, l1_size2; | |
971 | int i, refcount, ret; | |
972 | int errors = 0; | |
973 | ||
974 | l1_size2 = l1_size * sizeof(uint64_t); | |
975 | ||
976 | /* Mark L1 table as used */ | |
977 | errors += inc_refcounts(bs, refcount_table, refcount_table_size, | |
978 | l1_table_offset, l1_size2); | |
979 | ||
980 | /* Read L1 table entries from disk */ | |
702ef63f KW |
981 | if (l1_size2 == 0) { |
982 | l1_table = NULL; | |
983 | } else { | |
984 | l1_table = qemu_malloc(l1_size2); | |
66f82cee | 985 | if (bdrv_pread(bs->file, l1_table_offset, |
702ef63f KW |
986 | l1_table, l1_size2) != l1_size2) |
987 | goto fail; | |
988 | for(i = 0;i < l1_size; i++) | |
989 | be64_to_cpus(&l1_table[i]); | |
990 | } | |
f7d0fe02 KW |
991 | |
992 | /* Do the actual checks */ | |
993 | for(i = 0; i < l1_size; i++) { | |
994 | l2_offset = l1_table[i]; | |
995 | if (l2_offset) { | |
996 | /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ | |
997 | if (check_copied) { | |
998 | refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) | |
999 | >> s->cluster_bits); | |
1000 | if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { | |
1001 | fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64 | |
1002 | " refcount=%d\n", l2_offset, refcount); | |
1003 | errors++; | |
1004 | } | |
1005 | } | |
1006 | ||
1007 | /* Mark L2 table as used */ | |
1008 | l2_offset &= ~QCOW_OFLAG_COPIED; | |
1009 | errors += inc_refcounts(bs, refcount_table, | |
1010 | refcount_table_size, | |
1011 | l2_offset, | |
1012 | s->cluster_size); | |
1013 | ||
1014 | /* L2 tables are cluster aligned */ | |
1015 | if (l2_offset & (s->cluster_size - 1)) { | |
1016 | fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " | |
1017 | "cluster aligned; L1 entry corrupted\n", l2_offset); | |
1018 | errors++; | |
1019 | } | |
1020 | ||
1021 | /* Process and check L2 entries */ | |
1022 | ret = check_refcounts_l2(bs, refcount_table, refcount_table_size, | |
1023 | l2_offset, check_copied); | |
1024 | if (ret < 0) { | |
1025 | goto fail; | |
1026 | } | |
1027 | errors += ret; | |
1028 | } | |
1029 | } | |
1030 | qemu_free(l1_table); | |
1031 | return errors; | |
1032 | ||
1033 | fail: | |
1034 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); | |
1035 | qemu_free(l1_table); | |
1036 | return -EIO; | |
1037 | } | |
1038 | ||
1039 | /* | |
1040 | * Checks an image for refcount consistency. | |
1041 | * | |
1042 | * Returns 0 if no errors are found, the number of errors in case the image is | |
1043 | * detected as corrupted, and -errno when an internal error occured. | |
1044 | */ | |
ed6ccf0f | 1045 | int qcow2_check_refcounts(BlockDriverState *bs) |
f7d0fe02 KW |
1046 | { |
1047 | BDRVQcowState *s = bs->opaque; | |
1048 | int64_t size; | |
1049 | int nb_clusters, refcount1, refcount2, i; | |
1050 | QCowSnapshot *sn; | |
1051 | uint16_t *refcount_table; | |
1052 | int ret, errors = 0; | |
1053 | ||
66f82cee | 1054 | size = bdrv_getlength(bs->file); |
f7d0fe02 KW |
1055 | nb_clusters = size_to_clusters(s, size); |
1056 | refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t)); | |
1057 | ||
1058 | /* header */ | |
1059 | errors += inc_refcounts(bs, refcount_table, nb_clusters, | |
1060 | 0, s->cluster_size); | |
1061 | ||
1062 | /* current L1 table */ | |
1063 | ret = check_refcounts_l1(bs, refcount_table, nb_clusters, | |
1064 | s->l1_table_offset, s->l1_size, 1); | |
1065 | if (ret < 0) { | |
1066 | return ret; | |
1067 | } | |
1068 | errors += ret; | |
1069 | ||
1070 | /* snapshots */ | |
1071 | for(i = 0; i < s->nb_snapshots; i++) { | |
1072 | sn = s->snapshots + i; | |
1073 | check_refcounts_l1(bs, refcount_table, nb_clusters, | |
1074 | sn->l1_table_offset, sn->l1_size, 0); | |
1075 | } | |
1076 | errors += inc_refcounts(bs, refcount_table, nb_clusters, | |
1077 | s->snapshots_offset, s->snapshots_size); | |
1078 | ||
1079 | /* refcount data */ | |
1080 | errors += inc_refcounts(bs, refcount_table, nb_clusters, | |
1081 | s->refcount_table_offset, | |
1082 | s->refcount_table_size * sizeof(uint64_t)); | |
1083 | for(i = 0; i < s->refcount_table_size; i++) { | |
1084 | int64_t offset; | |
1085 | offset = s->refcount_table[i]; | |
746c3cb5 KW |
1086 | |
1087 | /* Refcount blocks are cluster aligned */ | |
1088 | if (offset & (s->cluster_size - 1)) { | |
1089 | fprintf(stderr, "ERROR refcount block %d is not " | |
1090 | "cluster aligned; refcount table entry corrupted\n", i); | |
1091 | errors++; | |
1092 | } | |
1093 | ||
f7d0fe02 KW |
1094 | if (offset != 0) { |
1095 | errors += inc_refcounts(bs, refcount_table, nb_clusters, | |
1096 | offset, s->cluster_size); | |
746c3cb5 KW |
1097 | if (refcount_table[offset / s->cluster_size] != 1) { |
1098 | fprintf(stderr, "ERROR refcount block %d refcount=%d\n", | |
1099 | i, refcount_table[offset / s->cluster_size]); | |
1100 | } | |
f7d0fe02 KW |
1101 | } |
1102 | } | |
1103 | ||
1104 | /* compare ref counts */ | |
1105 | for(i = 0; i < nb_clusters; i++) { | |
1106 | refcount1 = get_refcount(bs, i); | |
1107 | refcount2 = refcount_table[i]; | |
1108 | if (refcount1 != refcount2) { | |
1109 | fprintf(stderr, "ERROR cluster %d refcount=%d reference=%d\n", | |
1110 | i, refcount1, refcount2); | |
1111 | errors++; | |
1112 | } | |
1113 | } | |
1114 | ||
1115 | qemu_free(refcount_table); | |
1116 | ||
1117 | return errors; | |
1118 | } | |
1119 |