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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 | 46 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE); |
8b3b7206 KW |
47 | if (bdrv_pwrite_sync(bs->file, s->refcount_block_cache_offset, |
48 | s->refcount_block_cache, size) < 0) | |
3b88e52b KW |
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) { | |
e14e8ba5 KW |
96 | ret = write_refcount_block(bs); |
97 | if (ret < 0) { | |
98 | return ret; | |
99 | } | |
3b88e52b KW |
100 | } |
101 | ||
66f82cee KW |
102 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD); |
103 | ret = bdrv_pread(bs->file, refcount_block_offset, s->refcount_block_cache, | |
f7d0fe02 | 104 | s->cluster_size); |
e14e8ba5 KW |
105 | if (ret < 0) { |
106 | return ret; | |
107 | } | |
108 | ||
f7d0fe02 KW |
109 | s->refcount_block_cache_offset = refcount_block_offset; |
110 | return 0; | |
111 | } | |
112 | ||
018faafd KW |
113 | /* |
114 | * Returns the refcount of the cluster given by its index. Any non-negative | |
115 | * return value is the refcount of the cluster, negative values are -errno | |
116 | * and indicate an error. | |
117 | */ | |
f7d0fe02 KW |
118 | static int get_refcount(BlockDriverState *bs, int64_t cluster_index) |
119 | { | |
120 | BDRVQcowState *s = bs->opaque; | |
121 | int refcount_table_index, block_index; | |
122 | int64_t refcount_block_offset; | |
018faafd | 123 | int ret; |
f7d0fe02 KW |
124 | |
125 | refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
126 | if (refcount_table_index >= s->refcount_table_size) | |
127 | return 0; | |
128 | refcount_block_offset = s->refcount_table[refcount_table_index]; | |
129 | if (!refcount_block_offset) | |
130 | return 0; | |
131 | if (refcount_block_offset != s->refcount_block_cache_offset) { | |
132 | /* better than nothing: return allocated if read error */ | |
018faafd KW |
133 | ret = load_refcount_block(bs, refcount_block_offset); |
134 | if (ret < 0) { | |
135 | return ret; | |
136 | } | |
f7d0fe02 KW |
137 | } |
138 | block_index = cluster_index & | |
139 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
140 | return be16_to_cpu(s->refcount_block_cache[block_index]); | |
141 | } | |
142 | ||
05121aed KW |
143 | /* |
144 | * Rounds the refcount table size up to avoid growing the table for each single | |
145 | * refcount block that is allocated. | |
146 | */ | |
147 | static unsigned int next_refcount_table_size(BDRVQcowState *s, | |
148 | unsigned int min_size) | |
149 | { | |
150 | unsigned int min_clusters = (min_size >> (s->cluster_bits - 3)) + 1; | |
151 | unsigned int refcount_table_clusters = | |
152 | MAX(1, s->refcount_table_size >> (s->cluster_bits - 3)); | |
153 | ||
154 | while (min_clusters > refcount_table_clusters) { | |
155 | refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; | |
156 | } | |
157 | ||
158 | return refcount_table_clusters << (s->cluster_bits - 3); | |
159 | } | |
160 | ||
92dcb59f KW |
161 | |
162 | /* Checks if two offsets are described by the same refcount block */ | |
163 | static int in_same_refcount_block(BDRVQcowState *s, uint64_t offset_a, | |
164 | uint64_t offset_b) | |
165 | { | |
166 | uint64_t block_a = offset_a >> (2 * s->cluster_bits - REFCOUNT_SHIFT); | |
167 | uint64_t block_b = offset_b >> (2 * s->cluster_bits - REFCOUNT_SHIFT); | |
168 | ||
169 | return (block_a == block_b); | |
170 | } | |
171 | ||
172 | /* | |
173 | * Loads a refcount block. If it doesn't exist yet, it is allocated first | |
174 | * (including growing the refcount table if needed). | |
175 | * | |
176 | * Returns the offset of the refcount block on success or -errno in error case | |
177 | */ | |
178 | static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index) | |
f7d0fe02 KW |
179 | { |
180 | BDRVQcowState *s = bs->opaque; | |
92dcb59f KW |
181 | unsigned int refcount_table_index; |
182 | int ret; | |
183 | ||
66f82cee | 184 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); |
8252278a | 185 | |
92dcb59f KW |
186 | /* Find the refcount block for the given cluster */ |
187 | refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
188 | ||
189 | if (refcount_table_index < s->refcount_table_size) { | |
190 | ||
191 | uint64_t refcount_block_offset = | |
192 | s->refcount_table[refcount_table_index]; | |
193 | ||
194 | /* If it's already there, we're done */ | |
195 | if (refcount_block_offset) { | |
196 | if (refcount_block_offset != s->refcount_block_cache_offset) { | |
197 | ret = load_refcount_block(bs, refcount_block_offset); | |
198 | if (ret < 0) { | |
199 | return ret; | |
200 | } | |
201 | } | |
202 | return refcount_block_offset; | |
203 | } | |
204 | } | |
205 | ||
206 | /* | |
207 | * If we came here, we need to allocate something. Something is at least | |
208 | * a cluster for the new refcount block. It may also include a new refcount | |
209 | * table if the old refcount table is too small. | |
210 | * | |
211 | * Note that allocating clusters here needs some special care: | |
212 | * | |
213 | * - We can't use the normal qcow2_alloc_clusters(), it would try to | |
214 | * increase the refcount and very likely we would end up with an endless | |
215 | * recursion. Instead we must place the refcount blocks in a way that | |
216 | * they can describe them themselves. | |
217 | * | |
218 | * - We need to consider that at this point we are inside update_refcounts | |
219 | * and doing the initial refcount increase. This means that some clusters | |
220 | * have already been allocated by the caller, but their refcount isn't | |
221 | * accurate yet. free_cluster_index tells us where this allocation ends | |
222 | * as long as we don't overwrite it by freeing clusters. | |
223 | * | |
224 | * - alloc_clusters_noref and qcow2_free_clusters may load a different | |
225 | * refcount block into the cache | |
226 | */ | |
227 | ||
228 | if (cache_refcount_updates) { | |
66f82cee | 229 | ret = write_refcount_block(bs); |
92dcb59f KW |
230 | if (ret < 0) { |
231 | return ret; | |
232 | } | |
233 | } | |
234 | ||
235 | /* Allocate the refcount block itself and mark it as used */ | |
2eaa8f63 KW |
236 | int64_t new_block = alloc_clusters_noref(bs, s->cluster_size); |
237 | if (new_block < 0) { | |
238 | return new_block; | |
239 | } | |
f7d0fe02 | 240 | |
f7d0fe02 | 241 | #ifdef DEBUG_ALLOC2 |
92dcb59f KW |
242 | fprintf(stderr, "qcow2: Allocate refcount block %d for %" PRIx64 |
243 | " at %" PRIx64 "\n", | |
244 | refcount_table_index, cluster_index << s->cluster_bits, new_block); | |
f7d0fe02 | 245 | #endif |
92dcb59f KW |
246 | |
247 | if (in_same_refcount_block(s, new_block, cluster_index << s->cluster_bits)) { | |
25408c09 KW |
248 | /* Zero the new refcount block before updating it */ |
249 | memset(s->refcount_block_cache, 0, s->cluster_size); | |
250 | s->refcount_block_cache_offset = new_block; | |
251 | ||
92dcb59f KW |
252 | /* The block describes itself, need to update the cache */ |
253 | int block_index = (new_block >> s->cluster_bits) & | |
254 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
255 | s->refcount_block_cache[block_index] = cpu_to_be16(1); | |
256 | } else { | |
257 | /* Described somewhere else. This can recurse at most twice before we | |
258 | * arrive at a block that describes itself. */ | |
259 | ret = update_refcount(bs, new_block, s->cluster_size, 1); | |
260 | if (ret < 0) { | |
261 | goto fail_block; | |
262 | } | |
25408c09 KW |
263 | |
264 | /* Initialize the new refcount block only after updating its refcount, | |
265 | * update_refcount uses the refcount cache itself */ | |
266 | memset(s->refcount_block_cache, 0, s->cluster_size); | |
267 | s->refcount_block_cache_offset = new_block; | |
92dcb59f KW |
268 | } |
269 | ||
270 | /* Now the new refcount block needs to be written to disk */ | |
66f82cee | 271 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE); |
8b3b7206 | 272 | ret = bdrv_pwrite_sync(bs->file, new_block, s->refcount_block_cache, |
92dcb59f KW |
273 | s->cluster_size); |
274 | if (ret < 0) { | |
275 | goto fail_block; | |
276 | } | |
277 | ||
278 | /* If the refcount table is big enough, just hook the block up there */ | |
279 | if (refcount_table_index < s->refcount_table_size) { | |
280 | uint64_t data64 = cpu_to_be64(new_block); | |
66f82cee | 281 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_HOOKUP); |
8b3b7206 | 282 | ret = bdrv_pwrite_sync(bs->file, |
92dcb59f KW |
283 | s->refcount_table_offset + refcount_table_index * sizeof(uint64_t), |
284 | &data64, sizeof(data64)); | |
285 | if (ret < 0) { | |
286 | goto fail_block; | |
287 | } | |
288 | ||
289 | s->refcount_table[refcount_table_index] = new_block; | |
290 | return new_block; | |
291 | } | |
292 | ||
293 | /* | |
294 | * If we come here, we need to grow the refcount table. Again, a new | |
295 | * refcount table needs some space and we can't simply allocate to avoid | |
296 | * endless recursion. | |
297 | * | |
298 | * Therefore let's grab new refcount blocks at the end of the image, which | |
299 | * will describe themselves and the new refcount table. This way we can | |
300 | * reference them only in the new table and do the switch to the new | |
301 | * refcount table at once without producing an inconsistent state in | |
302 | * between. | |
303 | */ | |
66f82cee | 304 | BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW); |
8252278a | 305 | |
92dcb59f KW |
306 | /* Calculate the number of refcount blocks needed so far */ |
307 | uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT); | |
308 | uint64_t blocks_used = (s->free_cluster_index + | |
309 | refcount_block_clusters - 1) / refcount_block_clusters; | |
310 | ||
311 | /* And now we need at least one block more for the new metadata */ | |
312 | uint64_t table_size = next_refcount_table_size(s, blocks_used + 1); | |
313 | uint64_t last_table_size; | |
314 | uint64_t blocks_clusters; | |
315 | do { | |
316 | uint64_t table_clusters = size_to_clusters(s, table_size); | |
317 | blocks_clusters = 1 + | |
318 | ((table_clusters + refcount_block_clusters - 1) | |
319 | / refcount_block_clusters); | |
320 | uint64_t meta_clusters = table_clusters + blocks_clusters; | |
321 | ||
322 | last_table_size = table_size; | |
323 | table_size = next_refcount_table_size(s, blocks_used + | |
324 | ((meta_clusters + refcount_block_clusters - 1) | |
325 | / refcount_block_clusters)); | |
326 | ||
327 | } while (last_table_size != table_size); | |
328 | ||
329 | #ifdef DEBUG_ALLOC2 | |
330 | fprintf(stderr, "qcow2: Grow refcount table %" PRId32 " => %" PRId64 "\n", | |
331 | s->refcount_table_size, table_size); | |
332 | #endif | |
333 | ||
334 | /* Create the new refcount table and blocks */ | |
335 | uint64_t meta_offset = (blocks_used * refcount_block_clusters) * | |
336 | s->cluster_size; | |
337 | uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size; | |
338 | uint16_t *new_blocks = qemu_mallocz(blocks_clusters * s->cluster_size); | |
339 | uint64_t *new_table = qemu_mallocz(table_size * sizeof(uint64_t)); | |
340 | ||
341 | assert(meta_offset >= (s->free_cluster_index * s->cluster_size)); | |
342 | ||
343 | /* Fill the new refcount table */ | |
f7d0fe02 | 344 | memcpy(new_table, s->refcount_table, |
92dcb59f KW |
345 | s->refcount_table_size * sizeof(uint64_t)); |
346 | new_table[refcount_table_index] = new_block; | |
347 | ||
348 | int i; | |
349 | for (i = 0; i < blocks_clusters; i++) { | |
350 | new_table[blocks_used + i] = meta_offset + (i * s->cluster_size); | |
351 | } | |
352 | ||
353 | /* Fill the refcount blocks */ | |
354 | uint64_t table_clusters = size_to_clusters(s, table_size * sizeof(uint64_t)); | |
355 | int block = 0; | |
356 | for (i = 0; i < table_clusters + blocks_clusters; i++) { | |
357 | new_blocks[block++] = cpu_to_be16(1); | |
358 | } | |
359 | ||
360 | /* Write refcount blocks to disk */ | |
66f82cee | 361 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS); |
8b3b7206 | 362 | ret = bdrv_pwrite_sync(bs->file, meta_offset, new_blocks, |
92dcb59f KW |
363 | blocks_clusters * s->cluster_size); |
364 | qemu_free(new_blocks); | |
365 | if (ret < 0) { | |
366 | goto fail_table; | |
367 | } | |
368 | ||
369 | /* Write refcount table to disk */ | |
370 | for(i = 0; i < table_size; i++) { | |
371 | cpu_to_be64s(&new_table[i]); | |
372 | } | |
373 | ||
66f82cee | 374 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE); |
8b3b7206 | 375 | ret = bdrv_pwrite_sync(bs->file, table_offset, new_table, |
92dcb59f KW |
376 | table_size * sizeof(uint64_t)); |
377 | if (ret < 0) { | |
378 | goto fail_table; | |
379 | } | |
380 | ||
381 | for(i = 0; i < table_size; i++) { | |
f7d0fe02 | 382 | cpu_to_be64s(&new_table[i]); |
92dcb59f | 383 | } |
f7d0fe02 | 384 | |
92dcb59f KW |
385 | /* Hook up the new refcount table in the qcow2 header */ |
386 | uint8_t data[12]; | |
f7d0fe02 | 387 | cpu_to_be64w((uint64_t*)data, table_offset); |
92dcb59f | 388 | cpu_to_be32w((uint32_t*)(data + 8), table_clusters); |
66f82cee | 389 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE); |
8b3b7206 | 390 | ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, refcount_table_offset), |
92dcb59f KW |
391 | data, sizeof(data)); |
392 | if (ret < 0) { | |
393 | goto fail_table; | |
f2b7c8b3 KW |
394 | } |
395 | ||
92dcb59f KW |
396 | /* And switch it in memory */ |
397 | uint64_t old_table_offset = s->refcount_table_offset; | |
398 | uint64_t old_table_size = s->refcount_table_size; | |
399 | ||
f7d0fe02 | 400 | qemu_free(s->refcount_table); |
f7d0fe02 | 401 | s->refcount_table = new_table; |
92dcb59f | 402 | s->refcount_table_size = table_size; |
f7d0fe02 KW |
403 | s->refcount_table_offset = table_offset; |
404 | ||
92dcb59f KW |
405 | /* Free old table. Remember, we must not change free_cluster_index */ |
406 | uint64_t old_free_cluster_index = s->free_cluster_index; | |
ed6ccf0f | 407 | qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t)); |
92dcb59f | 408 | s->free_cluster_index = old_free_cluster_index; |
f7d0fe02 | 409 | |
92dcb59f KW |
410 | ret = load_refcount_block(bs, new_block); |
411 | if (ret < 0) { | |
412 | goto fail_block; | |
f7d0fe02 KW |
413 | } |
414 | ||
92dcb59f | 415 | return new_block; |
f7d0fe02 | 416 | |
92dcb59f KW |
417 | fail_table: |
418 | qemu_free(new_table); | |
419 | fail_block: | |
420 | s->refcount_block_cache_offset = 0; | |
421 | return ret; | |
f7d0fe02 KW |
422 | } |
423 | ||
9923e05e | 424 | #define REFCOUNTS_PER_SECTOR (512 >> REFCOUNT_SHIFT) |
66f82cee | 425 | static int write_refcount_block_entries(BlockDriverState *bs, |
9923e05e KW |
426 | int64_t refcount_block_offset, int first_index, int last_index) |
427 | { | |
66f82cee | 428 | BDRVQcowState *s = bs->opaque; |
9923e05e | 429 | size_t size; |
ed0df867 | 430 | int ret; |
9923e05e | 431 | |
3b88e52b KW |
432 | if (cache_refcount_updates) { |
433 | return 0; | |
434 | } | |
435 | ||
86fa8da8 KW |
436 | if (first_index < 0) { |
437 | return 0; | |
438 | } | |
439 | ||
9923e05e KW |
440 | first_index &= ~(REFCOUNTS_PER_SECTOR - 1); |
441 | last_index = (last_index + REFCOUNTS_PER_SECTOR) | |
442 | & ~(REFCOUNTS_PER_SECTOR - 1); | |
443 | ||
444 | size = (last_index - first_index) << REFCOUNT_SHIFT; | |
ed0df867 | 445 | |
66f82cee | 446 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE_PART); |
8b3b7206 | 447 | ret = bdrv_pwrite_sync(bs->file, |
9923e05e | 448 | refcount_block_offset + (first_index << REFCOUNT_SHIFT), |
ed0df867 KW |
449 | &s->refcount_block_cache[first_index], size); |
450 | if (ret < 0) { | |
451 | return ret; | |
9923e05e KW |
452 | } |
453 | ||
454 | return 0; | |
455 | } | |
456 | ||
f7d0fe02 | 457 | /* XXX: cache several refcount block clusters ? */ |
db3a964f KW |
458 | static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
459 | int64_t offset, int64_t length, int addend) | |
f7d0fe02 KW |
460 | { |
461 | BDRVQcowState *s = bs->opaque; | |
462 | int64_t start, last, cluster_offset; | |
463 | int64_t refcount_block_offset = 0; | |
464 | int64_t table_index = -1, old_table_index; | |
465 | int first_index = -1, last_index = -1; | |
09508d13 | 466 | int ret; |
f7d0fe02 KW |
467 | |
468 | #ifdef DEBUG_ALLOC2 | |
0bf9e31a | 469 | printf("update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", |
f7d0fe02 KW |
470 | offset, length, addend); |
471 | #endif | |
7322afe7 | 472 | if (length < 0) { |
f7d0fe02 | 473 | return -EINVAL; |
7322afe7 KW |
474 | } else if (length == 0) { |
475 | return 0; | |
476 | } | |
477 | ||
f7d0fe02 KW |
478 | start = offset & ~(s->cluster_size - 1); |
479 | last = (offset + length - 1) & ~(s->cluster_size - 1); | |
480 | for(cluster_offset = start; cluster_offset <= last; | |
481 | cluster_offset += s->cluster_size) | |
482 | { | |
483 | int block_index, refcount; | |
484 | int64_t cluster_index = cluster_offset >> s->cluster_bits; | |
09508d13 | 485 | int64_t new_block; |
f7d0fe02 KW |
486 | |
487 | /* Only write refcount block to disk when we are done with it */ | |
488 | old_table_index = table_index; | |
489 | table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
490 | if ((old_table_index >= 0) && (table_index != old_table_index)) { | |
9923e05e | 491 | |
ed0df867 KW |
492 | ret = write_refcount_block_entries(bs, refcount_block_offset, |
493 | first_index, last_index); | |
494 | if (ret < 0) { | |
495 | return ret; | |
f7d0fe02 KW |
496 | } |
497 | ||
498 | first_index = -1; | |
499 | last_index = -1; | |
500 | } | |
501 | ||
502 | /* Load the refcount block and allocate it if needed */ | |
09508d13 KW |
503 | new_block = alloc_refcount_block(bs, cluster_index); |
504 | if (new_block < 0) { | |
505 | ret = new_block; | |
506 | goto fail; | |
f7d0fe02 | 507 | } |
09508d13 | 508 | refcount_block_offset = new_block; |
f7d0fe02 KW |
509 | |
510 | /* we can update the count and save it */ | |
511 | block_index = cluster_index & | |
512 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
513 | if (first_index == -1 || block_index < first_index) { | |
514 | first_index = block_index; | |
515 | } | |
516 | if (block_index > last_index) { | |
517 | last_index = block_index; | |
518 | } | |
519 | ||
520 | refcount = be16_to_cpu(s->refcount_block_cache[block_index]); | |
521 | refcount += addend; | |
09508d13 KW |
522 | if (refcount < 0 || refcount > 0xffff) { |
523 | ret = -EINVAL; | |
524 | goto fail; | |
525 | } | |
f7d0fe02 KW |
526 | if (refcount == 0 && cluster_index < s->free_cluster_index) { |
527 | s->free_cluster_index = cluster_index; | |
528 | } | |
529 | s->refcount_block_cache[block_index] = cpu_to_be16(refcount); | |
530 | } | |
531 | ||
09508d13 KW |
532 | ret = 0; |
533 | fail: | |
534 | ||
f7d0fe02 KW |
535 | /* Write last changed block to disk */ |
536 | if (refcount_block_offset != 0) { | |
ed0df867 KW |
537 | int wret; |
538 | wret = write_refcount_block_entries(bs, refcount_block_offset, | |
539 | first_index, last_index); | |
540 | if (wret < 0) { | |
541 | return ret < 0 ? ret : wret; | |
f7d0fe02 KW |
542 | } |
543 | } | |
544 | ||
09508d13 KW |
545 | /* |
546 | * Try do undo any updates if an error is returned (This may succeed in | |
547 | * some cases like ENOSPC for allocating a new refcount block) | |
548 | */ | |
549 | if (ret < 0) { | |
550 | int dummy; | |
551 | dummy = update_refcount(bs, offset, cluster_offset - offset, -addend); | |
552 | } | |
553 | ||
554 | return ret; | |
f7d0fe02 KW |
555 | } |
556 | ||
018faafd KW |
557 | /* |
558 | * Increases or decreases the refcount of a given cluster by one. | |
559 | * addend must be 1 or -1. | |
560 | * | |
561 | * If the return value is non-negative, it is the new refcount of the cluster. | |
562 | * If it is negative, it is -errno and indicates an error. | |
563 | */ | |
f7d0fe02 KW |
564 | static int update_cluster_refcount(BlockDriverState *bs, |
565 | int64_t cluster_index, | |
566 | int addend) | |
567 | { | |
568 | BDRVQcowState *s = bs->opaque; | |
569 | int ret; | |
570 | ||
571 | ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend); | |
572 | if (ret < 0) { | |
573 | return ret; | |
574 | } | |
575 | ||
576 | return get_refcount(bs, cluster_index); | |
577 | } | |
578 | ||
579 | ||
580 | ||
581 | /*********************************************************/ | |
582 | /* cluster allocation functions */ | |
583 | ||
584 | ||
585 | ||
586 | /* return < 0 if error */ | |
587 | static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size) | |
588 | { | |
589 | BDRVQcowState *s = bs->opaque; | |
2eaa8f63 | 590 | int i, nb_clusters, refcount; |
f7d0fe02 KW |
591 | |
592 | nb_clusters = size_to_clusters(s, size); | |
593 | retry: | |
594 | for(i = 0; i < nb_clusters; i++) { | |
508e0893 | 595 | int64_t next_cluster_index = s->free_cluster_index++; |
2eaa8f63 KW |
596 | refcount = get_refcount(bs, next_cluster_index); |
597 | ||
598 | if (refcount < 0) { | |
599 | return refcount; | |
600 | } else if (refcount != 0) { | |
f7d0fe02 | 601 | goto retry; |
2eaa8f63 | 602 | } |
f7d0fe02 KW |
603 | } |
604 | #ifdef DEBUG_ALLOC2 | |
0bf9e31a | 605 | printf("alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n", |
f7d0fe02 KW |
606 | size, |
607 | (s->free_cluster_index - nb_clusters) << s->cluster_bits); | |
608 | #endif | |
609 | return (s->free_cluster_index - nb_clusters) << s->cluster_bits; | |
610 | } | |
611 | ||
ed6ccf0f | 612 | int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size) |
f7d0fe02 KW |
613 | { |
614 | int64_t offset; | |
db3a964f | 615 | int ret; |
f7d0fe02 | 616 | |
66f82cee | 617 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); |
f7d0fe02 | 618 | offset = alloc_clusters_noref(bs, size); |
2eaa8f63 KW |
619 | if (offset < 0) { |
620 | return offset; | |
621 | } | |
622 | ||
db3a964f KW |
623 | ret = update_refcount(bs, offset, size, 1); |
624 | if (ret < 0) { | |
625 | return ret; | |
626 | } | |
f7d0fe02 KW |
627 | return offset; |
628 | } | |
629 | ||
630 | /* only used to allocate compressed sectors. We try to allocate | |
631 | contiguous sectors. size must be <= cluster_size */ | |
ed6ccf0f | 632 | int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) |
f7d0fe02 KW |
633 | { |
634 | BDRVQcowState *s = bs->opaque; | |
635 | int64_t offset, cluster_offset; | |
636 | int free_in_cluster; | |
637 | ||
66f82cee | 638 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); |
f7d0fe02 KW |
639 | assert(size > 0 && size <= s->cluster_size); |
640 | if (s->free_byte_offset == 0) { | |
ed6ccf0f | 641 | s->free_byte_offset = qcow2_alloc_clusters(bs, s->cluster_size); |
5d757b56 KW |
642 | if (s->free_byte_offset < 0) { |
643 | return s->free_byte_offset; | |
644 | } | |
f7d0fe02 KW |
645 | } |
646 | redo: | |
647 | free_in_cluster = s->cluster_size - | |
648 | (s->free_byte_offset & (s->cluster_size - 1)); | |
649 | if (size <= free_in_cluster) { | |
650 | /* enough space in current cluster */ | |
651 | offset = s->free_byte_offset; | |
652 | s->free_byte_offset += size; | |
653 | free_in_cluster -= size; | |
654 | if (free_in_cluster == 0) | |
655 | s->free_byte_offset = 0; | |
656 | if ((offset & (s->cluster_size - 1)) != 0) | |
657 | update_cluster_refcount(bs, offset >> s->cluster_bits, 1); | |
658 | } else { | |
ed6ccf0f | 659 | offset = qcow2_alloc_clusters(bs, s->cluster_size); |
5d757b56 KW |
660 | if (offset < 0) { |
661 | return offset; | |
662 | } | |
f7d0fe02 KW |
663 | cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1); |
664 | if ((cluster_offset + s->cluster_size) == offset) { | |
665 | /* we are lucky: contiguous data */ | |
666 | offset = s->free_byte_offset; | |
667 | update_cluster_refcount(bs, offset >> s->cluster_bits, 1); | |
668 | s->free_byte_offset += size; | |
669 | } else { | |
670 | s->free_byte_offset = offset; | |
671 | goto redo; | |
672 | } | |
673 | } | |
674 | return offset; | |
675 | } | |
676 | ||
ed6ccf0f | 677 | void qcow2_free_clusters(BlockDriverState *bs, |
f7d0fe02 KW |
678 | int64_t offset, int64_t size) |
679 | { | |
db3a964f KW |
680 | int ret; |
681 | ||
66f82cee | 682 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE); |
db3a964f KW |
683 | ret = update_refcount(bs, offset, size, -1); |
684 | if (ret < 0) { | |
685 | fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret)); | |
003fad6e | 686 | /* TODO Remember the clusters to free them later and avoid leaking */ |
db3a964f | 687 | } |
f7d0fe02 KW |
688 | } |
689 | ||
45aba42f KW |
690 | /* |
691 | * free_any_clusters | |
692 | * | |
693 | * free clusters according to its type: compressed or not | |
694 | * | |
695 | */ | |
696 | ||
ed6ccf0f | 697 | void qcow2_free_any_clusters(BlockDriverState *bs, |
45aba42f KW |
698 | uint64_t cluster_offset, int nb_clusters) |
699 | { | |
700 | BDRVQcowState *s = bs->opaque; | |
701 | ||
702 | /* free the cluster */ | |
703 | ||
704 | if (cluster_offset & QCOW_OFLAG_COMPRESSED) { | |
705 | int nb_csectors; | |
706 | nb_csectors = ((cluster_offset >> s->csize_shift) & | |
707 | s->csize_mask) + 1; | |
ed6ccf0f KW |
708 | qcow2_free_clusters(bs, |
709 | (cluster_offset & s->cluster_offset_mask) & ~511, | |
710 | nb_csectors * 512); | |
45aba42f KW |
711 | return; |
712 | } | |
713 | ||
ed6ccf0f | 714 | qcow2_free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits); |
45aba42f KW |
715 | |
716 | return; | |
717 | } | |
718 | ||
f7d0fe02 KW |
719 | |
720 | ||
721 | /*********************************************************/ | |
722 | /* snapshots and image creation */ | |
723 | ||
724 | ||
725 | ||
ed6ccf0f KW |
726 | void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset, |
727 | int64_t size) | |
f7d0fe02 KW |
728 | { |
729 | int refcount; | |
730 | int64_t start, last, cluster_offset; | |
731 | uint16_t *p; | |
732 | ||
733 | start = offset & ~(s->cluster_size - 1); | |
734 | last = (offset + size - 1) & ~(s->cluster_size - 1); | |
735 | for(cluster_offset = start; cluster_offset <= last; | |
736 | cluster_offset += s->cluster_size) { | |
737 | p = &s->refcount_block[cluster_offset >> s->cluster_bits]; | |
738 | refcount = be16_to_cpu(*p); | |
739 | refcount++; | |
740 | *p = cpu_to_be16(refcount); | |
741 | } | |
742 | } | |
743 | ||
744 | /* update the refcounts of snapshots and the copied flag */ | |
ed6ccf0f KW |
745 | int qcow2_update_snapshot_refcount(BlockDriverState *bs, |
746 | int64_t l1_table_offset, int l1_size, int addend) | |
f7d0fe02 KW |
747 | { |
748 | BDRVQcowState *s = bs->opaque; | |
749 | uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; | |
750 | int64_t old_offset, old_l2_offset; | |
751 | int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount; | |
752 | ||
ed6ccf0f | 753 | qcow2_l2_cache_reset(bs); |
3b88e52b | 754 | cache_refcount_updates = 1; |
f7d0fe02 KW |
755 | |
756 | l2_table = NULL; | |
757 | l1_table = NULL; | |
758 | l1_size2 = l1_size * sizeof(uint64_t); | |
f7d0fe02 | 759 | if (l1_table_offset != s->l1_table_offset) { |
702ef63f KW |
760 | if (l1_size2 != 0) { |
761 | l1_table = qemu_mallocz(align_offset(l1_size2, 512)); | |
762 | } else { | |
763 | l1_table = NULL; | |
764 | } | |
f7d0fe02 | 765 | l1_allocated = 1; |
66f82cee | 766 | if (bdrv_pread(bs->file, l1_table_offset, |
f7d0fe02 KW |
767 | l1_table, l1_size2) != l1_size2) |
768 | goto fail; | |
769 | for(i = 0;i < l1_size; i++) | |
770 | be64_to_cpus(&l1_table[i]); | |
771 | } else { | |
772 | assert(l1_size == s->l1_size); | |
773 | l1_table = s->l1_table; | |
774 | l1_allocated = 0; | |
775 | } | |
776 | ||
777 | l2_size = s->l2_size * sizeof(uint64_t); | |
778 | l2_table = qemu_malloc(l2_size); | |
779 | l1_modified = 0; | |
780 | for(i = 0; i < l1_size; i++) { | |
781 | l2_offset = l1_table[i]; | |
782 | if (l2_offset) { | |
783 | old_l2_offset = l2_offset; | |
784 | l2_offset &= ~QCOW_OFLAG_COPIED; | |
785 | l2_modified = 0; | |
66f82cee | 786 | if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size) |
f7d0fe02 KW |
787 | goto fail; |
788 | for(j = 0; j < s->l2_size; j++) { | |
789 | offset = be64_to_cpu(l2_table[j]); | |
790 | if (offset != 0) { | |
791 | old_offset = offset; | |
792 | offset &= ~QCOW_OFLAG_COPIED; | |
793 | if (offset & QCOW_OFLAG_COMPRESSED) { | |
794 | nb_csectors = ((offset >> s->csize_shift) & | |
795 | s->csize_mask) + 1; | |
db3a964f KW |
796 | if (addend != 0) { |
797 | int ret; | |
798 | ret = update_refcount(bs, | |
799 | (offset & s->cluster_offset_mask) & ~511, | |
800 | nb_csectors * 512, addend); | |
801 | if (ret < 0) { | |
802 | goto fail; | |
803 | } | |
804 | } | |
f7d0fe02 KW |
805 | /* compressed clusters are never modified */ |
806 | refcount = 2; | |
807 | } else { | |
808 | if (addend != 0) { | |
809 | refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend); | |
810 | } else { | |
811 | refcount = get_refcount(bs, offset >> s->cluster_bits); | |
812 | } | |
018faafd KW |
813 | |
814 | if (refcount < 0) { | |
815 | goto fail; | |
816 | } | |
f7d0fe02 KW |
817 | } |
818 | ||
819 | if (refcount == 1) { | |
820 | offset |= QCOW_OFLAG_COPIED; | |
821 | } | |
822 | if (offset != old_offset) { | |
823 | l2_table[j] = cpu_to_be64(offset); | |
824 | l2_modified = 1; | |
825 | } | |
826 | } | |
827 | } | |
828 | if (l2_modified) { | |
8b3b7206 KW |
829 | if (bdrv_pwrite_sync(bs->file, |
830 | l2_offset, l2_table, l2_size) < 0) | |
f7d0fe02 KW |
831 | goto fail; |
832 | } | |
833 | ||
834 | if (addend != 0) { | |
835 | refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend); | |
836 | } else { | |
837 | refcount = get_refcount(bs, l2_offset >> s->cluster_bits); | |
838 | } | |
018faafd KW |
839 | if (refcount < 0) { |
840 | goto fail; | |
841 | } else if (refcount == 1) { | |
f7d0fe02 KW |
842 | l2_offset |= QCOW_OFLAG_COPIED; |
843 | } | |
844 | if (l2_offset != old_l2_offset) { | |
845 | l1_table[i] = l2_offset; | |
846 | l1_modified = 1; | |
847 | } | |
848 | } | |
849 | } | |
850 | if (l1_modified) { | |
851 | for(i = 0; i < l1_size; i++) | |
852 | cpu_to_be64s(&l1_table[i]); | |
8b3b7206 KW |
853 | if (bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table, |
854 | l1_size2) < 0) | |
f7d0fe02 KW |
855 | goto fail; |
856 | for(i = 0; i < l1_size; i++) | |
857 | be64_to_cpus(&l1_table[i]); | |
858 | } | |
859 | if (l1_allocated) | |
860 | qemu_free(l1_table); | |
861 | qemu_free(l2_table); | |
3b88e52b | 862 | cache_refcount_updates = 0; |
66f82cee | 863 | write_refcount_block(bs); |
f7d0fe02 KW |
864 | return 0; |
865 | fail: | |
866 | if (l1_allocated) | |
867 | qemu_free(l1_table); | |
868 | qemu_free(l2_table); | |
3b88e52b | 869 | cache_refcount_updates = 0; |
66f82cee | 870 | write_refcount_block(bs); |
f7d0fe02 KW |
871 | return -EIO; |
872 | } | |
873 | ||
874 | ||
875 | ||
876 | ||
877 | /*********************************************************/ | |
878 | /* refcount checking functions */ | |
879 | ||
880 | ||
881 | ||
882 | /* | |
883 | * Increases the refcount for a range of clusters in a given refcount table. | |
884 | * This is used to construct a temporary refcount table out of L1 and L2 tables | |
885 | * which can be compared the the refcount table saved in the image. | |
886 | * | |
9ac228e0 | 887 | * Modifies the number of errors in res. |
f7d0fe02 | 888 | */ |
9ac228e0 KW |
889 | static void inc_refcounts(BlockDriverState *bs, |
890 | BdrvCheckResult *res, | |
f7d0fe02 KW |
891 | uint16_t *refcount_table, |
892 | int refcount_table_size, | |
893 | int64_t offset, int64_t size) | |
894 | { | |
895 | BDRVQcowState *s = bs->opaque; | |
896 | int64_t start, last, cluster_offset; | |
897 | int k; | |
f7d0fe02 KW |
898 | |
899 | if (size <= 0) | |
9ac228e0 | 900 | return; |
f7d0fe02 KW |
901 | |
902 | start = offset & ~(s->cluster_size - 1); | |
903 | last = (offset + size - 1) & ~(s->cluster_size - 1); | |
904 | for(cluster_offset = start; cluster_offset <= last; | |
905 | cluster_offset += s->cluster_size) { | |
906 | k = cluster_offset >> s->cluster_bits; | |
9ac228e0 | 907 | if (k < 0) { |
f7d0fe02 KW |
908 | fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", |
909 | cluster_offset); | |
9ac228e0 KW |
910 | res->corruptions++; |
911 | } else if (k >= refcount_table_size) { | |
912 | fprintf(stderr, "Warning: cluster offset=0x%" PRIx64 " is after " | |
913 | "the end of the image file, can't properly check refcounts.\n", | |
914 | cluster_offset); | |
915 | res->check_errors++; | |
f7d0fe02 KW |
916 | } else { |
917 | if (++refcount_table[k] == 0) { | |
918 | fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 | |
919 | "\n", cluster_offset); | |
9ac228e0 | 920 | res->corruptions++; |
f7d0fe02 KW |
921 | } |
922 | } | |
923 | } | |
f7d0fe02 KW |
924 | } |
925 | ||
926 | /* | |
927 | * Increases the refcount in the given refcount table for the all clusters | |
928 | * referenced in the L2 table. While doing so, performs some checks on L2 | |
929 | * entries. | |
930 | * | |
931 | * Returns the number of errors found by the checks or -errno if an internal | |
932 | * error occurred. | |
933 | */ | |
9ac228e0 | 934 | static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, |
f7d0fe02 KW |
935 | uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset, |
936 | int check_copied) | |
937 | { | |
938 | BDRVQcowState *s = bs->opaque; | |
939 | uint64_t *l2_table, offset; | |
940 | int i, l2_size, nb_csectors, refcount; | |
f7d0fe02 KW |
941 | |
942 | /* Read L2 table from disk */ | |
943 | l2_size = s->l2_size * sizeof(uint64_t); | |
944 | l2_table = qemu_malloc(l2_size); | |
945 | ||
66f82cee | 946 | if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size) |
f7d0fe02 KW |
947 | goto fail; |
948 | ||
949 | /* Do the actual checks */ | |
950 | for(i = 0; i < s->l2_size; i++) { | |
951 | offset = be64_to_cpu(l2_table[i]); | |
952 | if (offset != 0) { | |
953 | if (offset & QCOW_OFLAG_COMPRESSED) { | |
954 | /* Compressed clusters don't have QCOW_OFLAG_COPIED */ | |
955 | if (offset & QCOW_OFLAG_COPIED) { | |
956 | fprintf(stderr, "ERROR: cluster %" PRId64 ": " | |
957 | "copied flag must never be set for compressed " | |
958 | "clusters\n", offset >> s->cluster_bits); | |
959 | offset &= ~QCOW_OFLAG_COPIED; | |
9ac228e0 | 960 | res->corruptions++; |
f7d0fe02 KW |
961 | } |
962 | ||
963 | /* Mark cluster as used */ | |
964 | nb_csectors = ((offset >> s->csize_shift) & | |
965 | s->csize_mask) + 1; | |
966 | offset &= s->cluster_offset_mask; | |
9ac228e0 KW |
967 | inc_refcounts(bs, res, refcount_table, refcount_table_size, |
968 | offset & ~511, nb_csectors * 512); | |
f7d0fe02 KW |
969 | } else { |
970 | /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ | |
971 | if (check_copied) { | |
972 | uint64_t entry = offset; | |
973 | offset &= ~QCOW_OFLAG_COPIED; | |
974 | refcount = get_refcount(bs, offset >> s->cluster_bits); | |
018faafd KW |
975 | if (refcount < 0) { |
976 | fprintf(stderr, "Can't get refcount for offset %" | |
977 | PRIx64 ": %s\n", entry, strerror(-refcount)); | |
9ac228e0 | 978 | goto fail; |
018faafd | 979 | } |
f7d0fe02 KW |
980 | if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) { |
981 | fprintf(stderr, "ERROR OFLAG_COPIED: offset=%" | |
982 | PRIx64 " refcount=%d\n", entry, refcount); | |
9ac228e0 | 983 | res->corruptions++; |
f7d0fe02 KW |
984 | } |
985 | } | |
986 | ||
987 | /* Mark cluster as used */ | |
988 | offset &= ~QCOW_OFLAG_COPIED; | |
9ac228e0 KW |
989 | inc_refcounts(bs, res, refcount_table,refcount_table_size, |
990 | offset, s->cluster_size); | |
f7d0fe02 KW |
991 | |
992 | /* Correct offsets are cluster aligned */ | |
993 | if (offset & (s->cluster_size - 1)) { | |
994 | fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " | |
995 | "properly aligned; L2 entry corrupted.\n", offset); | |
9ac228e0 | 996 | res->corruptions++; |
f7d0fe02 KW |
997 | } |
998 | } | |
999 | } | |
1000 | } | |
1001 | ||
1002 | qemu_free(l2_table); | |
9ac228e0 | 1003 | return 0; |
f7d0fe02 KW |
1004 | |
1005 | fail: | |
9ac228e0 | 1006 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n"); |
f7d0fe02 KW |
1007 | qemu_free(l2_table); |
1008 | return -EIO; | |
1009 | } | |
1010 | ||
1011 | /* | |
1012 | * Increases the refcount for the L1 table, its L2 tables and all referenced | |
1013 | * clusters in the given refcount table. While doing so, performs some checks | |
1014 | * on L1 and L2 entries. | |
1015 | * | |
1016 | * Returns the number of errors found by the checks or -errno if an internal | |
1017 | * error occurred. | |
1018 | */ | |
1019 | static int check_refcounts_l1(BlockDriverState *bs, | |
9ac228e0 | 1020 | BdrvCheckResult *res, |
f7d0fe02 KW |
1021 | uint16_t *refcount_table, |
1022 | int refcount_table_size, | |
1023 | int64_t l1_table_offset, int l1_size, | |
1024 | int check_copied) | |
1025 | { | |
1026 | BDRVQcowState *s = bs->opaque; | |
1027 | uint64_t *l1_table, l2_offset, l1_size2; | |
1028 | int i, refcount, ret; | |
f7d0fe02 KW |
1029 | |
1030 | l1_size2 = l1_size * sizeof(uint64_t); | |
1031 | ||
1032 | /* Mark L1 table as used */ | |
9ac228e0 KW |
1033 | inc_refcounts(bs, res, refcount_table, refcount_table_size, |
1034 | l1_table_offset, l1_size2); | |
f7d0fe02 KW |
1035 | |
1036 | /* Read L1 table entries from disk */ | |
702ef63f KW |
1037 | if (l1_size2 == 0) { |
1038 | l1_table = NULL; | |
1039 | } else { | |
1040 | l1_table = qemu_malloc(l1_size2); | |
66f82cee | 1041 | if (bdrv_pread(bs->file, l1_table_offset, |
702ef63f KW |
1042 | l1_table, l1_size2) != l1_size2) |
1043 | goto fail; | |
1044 | for(i = 0;i < l1_size; i++) | |
1045 | be64_to_cpus(&l1_table[i]); | |
1046 | } | |
f7d0fe02 KW |
1047 | |
1048 | /* Do the actual checks */ | |
1049 | for(i = 0; i < l1_size; i++) { | |
1050 | l2_offset = l1_table[i]; | |
1051 | if (l2_offset) { | |
1052 | /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ | |
1053 | if (check_copied) { | |
1054 | refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) | |
1055 | >> s->cluster_bits); | |
018faafd KW |
1056 | if (refcount < 0) { |
1057 | fprintf(stderr, "Can't get refcount for l2_offset %" | |
1058 | PRIx64 ": %s\n", l2_offset, strerror(-refcount)); | |
9ac228e0 | 1059 | goto fail; |
018faafd | 1060 | } |
f7d0fe02 KW |
1061 | if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { |
1062 | fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64 | |
1063 | " refcount=%d\n", l2_offset, refcount); | |
9ac228e0 | 1064 | res->corruptions++; |
f7d0fe02 KW |
1065 | } |
1066 | } | |
1067 | ||
1068 | /* Mark L2 table as used */ | |
1069 | l2_offset &= ~QCOW_OFLAG_COPIED; | |
9ac228e0 KW |
1070 | inc_refcounts(bs, res, refcount_table, refcount_table_size, |
1071 | l2_offset, s->cluster_size); | |
f7d0fe02 KW |
1072 | |
1073 | /* L2 tables are cluster aligned */ | |
1074 | if (l2_offset & (s->cluster_size - 1)) { | |
1075 | fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " | |
1076 | "cluster aligned; L1 entry corrupted\n", l2_offset); | |
9ac228e0 | 1077 | res->corruptions++; |
f7d0fe02 KW |
1078 | } |
1079 | ||
1080 | /* Process and check L2 entries */ | |
9ac228e0 KW |
1081 | ret = check_refcounts_l2(bs, res, refcount_table, |
1082 | refcount_table_size, l2_offset, check_copied); | |
f7d0fe02 KW |
1083 | if (ret < 0) { |
1084 | goto fail; | |
1085 | } | |
f7d0fe02 KW |
1086 | } |
1087 | } | |
1088 | qemu_free(l1_table); | |
9ac228e0 | 1089 | return 0; |
f7d0fe02 KW |
1090 | |
1091 | fail: | |
1092 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); | |
9ac228e0 | 1093 | res->check_errors++; |
f7d0fe02 KW |
1094 | qemu_free(l1_table); |
1095 | return -EIO; | |
1096 | } | |
1097 | ||
1098 | /* | |
1099 | * Checks an image for refcount consistency. | |
1100 | * | |
1101 | * Returns 0 if no errors are found, the number of errors in case the image is | |
1102 | * detected as corrupted, and -errno when an internal error occured. | |
1103 | */ | |
9ac228e0 | 1104 | int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res) |
f7d0fe02 KW |
1105 | { |
1106 | BDRVQcowState *s = bs->opaque; | |
1107 | int64_t size; | |
1108 | int nb_clusters, refcount1, refcount2, i; | |
1109 | QCowSnapshot *sn; | |
1110 | uint16_t *refcount_table; | |
9ac228e0 | 1111 | int ret; |
f7d0fe02 | 1112 | |
66f82cee | 1113 | size = bdrv_getlength(bs->file); |
f7d0fe02 KW |
1114 | nb_clusters = size_to_clusters(s, size); |
1115 | refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t)); | |
1116 | ||
1117 | /* header */ | |
9ac228e0 KW |
1118 | inc_refcounts(bs, res, refcount_table, nb_clusters, |
1119 | 0, s->cluster_size); | |
f7d0fe02 KW |
1120 | |
1121 | /* current L1 table */ | |
9ac228e0 | 1122 | ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
f7d0fe02 KW |
1123 | s->l1_table_offset, s->l1_size, 1); |
1124 | if (ret < 0) { | |
1125 | return ret; | |
1126 | } | |
f7d0fe02 KW |
1127 | |
1128 | /* snapshots */ | |
1129 | for(i = 0; i < s->nb_snapshots; i++) { | |
1130 | sn = s->snapshots + i; | |
9ac228e0 KW |
1131 | ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
1132 | sn->l1_table_offset, sn->l1_size, 0); | |
1133 | if (ret < 0) { | |
1134 | return ret; | |
1135 | } | |
f7d0fe02 | 1136 | } |
9ac228e0 KW |
1137 | inc_refcounts(bs, res, refcount_table, nb_clusters, |
1138 | s->snapshots_offset, s->snapshots_size); | |
f7d0fe02 KW |
1139 | |
1140 | /* refcount data */ | |
9ac228e0 KW |
1141 | inc_refcounts(bs, res, refcount_table, nb_clusters, |
1142 | s->refcount_table_offset, | |
1143 | s->refcount_table_size * sizeof(uint64_t)); | |
1144 | ||
f7d0fe02 | 1145 | for(i = 0; i < s->refcount_table_size; i++) { |
6882c8fa | 1146 | uint64_t offset, cluster; |
f7d0fe02 | 1147 | offset = s->refcount_table[i]; |
6882c8fa | 1148 | cluster = offset >> s->cluster_bits; |
746c3cb5 KW |
1149 | |
1150 | /* Refcount blocks are cluster aligned */ | |
1151 | if (offset & (s->cluster_size - 1)) { | |
1152 | fprintf(stderr, "ERROR refcount block %d is not " | |
1153 | "cluster aligned; refcount table entry corrupted\n", i); | |
9ac228e0 | 1154 | res->corruptions++; |
6882c8fa KW |
1155 | continue; |
1156 | } | |
1157 | ||
1158 | if (cluster >= nb_clusters) { | |
1159 | fprintf(stderr, "ERROR refcount block %d is outside image\n", i); | |
9ac228e0 | 1160 | res->corruptions++; |
6882c8fa | 1161 | continue; |
746c3cb5 KW |
1162 | } |
1163 | ||
f7d0fe02 | 1164 | if (offset != 0) { |
9ac228e0 KW |
1165 | inc_refcounts(bs, res, refcount_table, nb_clusters, |
1166 | offset, s->cluster_size); | |
6882c8fa | 1167 | if (refcount_table[cluster] != 1) { |
746c3cb5 | 1168 | fprintf(stderr, "ERROR refcount block %d refcount=%d\n", |
6882c8fa | 1169 | i, refcount_table[cluster]); |
9ac228e0 | 1170 | res->corruptions++; |
746c3cb5 | 1171 | } |
f7d0fe02 KW |
1172 | } |
1173 | } | |
1174 | ||
1175 | /* compare ref counts */ | |
1176 | for(i = 0; i < nb_clusters; i++) { | |
1177 | refcount1 = get_refcount(bs, i); | |
018faafd KW |
1178 | if (refcount1 < 0) { |
1179 | fprintf(stderr, "Can't get refcount for cluster %d: %s\n", | |
1180 | i, strerror(-refcount1)); | |
9ac228e0 | 1181 | res->check_errors++; |
f74550fd | 1182 | continue; |
018faafd KW |
1183 | } |
1184 | ||
f7d0fe02 KW |
1185 | refcount2 = refcount_table[i]; |
1186 | if (refcount1 != refcount2) { | |
9ac228e0 KW |
1187 | fprintf(stderr, "%s cluster %d refcount=%d reference=%d\n", |
1188 | refcount1 < refcount2 ? "ERROR" : "Leaked", | |
f7d0fe02 | 1189 | i, refcount1, refcount2); |
9ac228e0 KW |
1190 | if (refcount1 < refcount2) { |
1191 | res->corruptions++; | |
1192 | } else { | |
1193 | res->leaks++; | |
1194 | } | |
f7d0fe02 KW |
1195 | } |
1196 | } | |
1197 | ||
1198 | qemu_free(refcount_table); | |
1199 | ||
9ac228e0 | 1200 | return 0; |
f7d0fe02 KW |
1201 | } |
1202 |