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/osdep.h" |
26 | #include "qapi/error.h" |
27 | #include "qcow2.h" |
28 | #include "qemu/range.h" |
29 | #include "qemu/bswap.h" |
30 | #include "qemu/cutils.h" |
31 | #include "trace.h" |
32 | |
33 | static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size, |
34 | uint64_t max); |
35 | static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
36 | int64_t offset, int64_t length, uint64_t addend, |
37 | bool decrease, enum qcow2_discard_type type); |
38 | |
39 | static uint64_t get_refcount_ro0(const void *refcount_array, uint64_t index); |
40 | static uint64_t get_refcount_ro1(const void *refcount_array, uint64_t index); |
41 | static uint64_t get_refcount_ro2(const void *refcount_array, uint64_t index); |
42 | static uint64_t get_refcount_ro3(const void *refcount_array, uint64_t index); |
43 | static uint64_t get_refcount_ro4(const void *refcount_array, uint64_t index); |
44 | static uint64_t get_refcount_ro5(const void *refcount_array, uint64_t index); |
45 | static uint64_t get_refcount_ro6(const void *refcount_array, uint64_t index); |
46 | |
47 | static void set_refcount_ro0(void *refcount_array, uint64_t index, |
48 | uint64_t value); |
49 | static void set_refcount_ro1(void *refcount_array, uint64_t index, |
50 | uint64_t value); |
51 | static void set_refcount_ro2(void *refcount_array, uint64_t index, |
52 | uint64_t value); |
53 | static void set_refcount_ro3(void *refcount_array, uint64_t index, |
54 | uint64_t value); |
55 | static void set_refcount_ro4(void *refcount_array, uint64_t index, |
56 | uint64_t value); |
57 | static void set_refcount_ro5(void *refcount_array, uint64_t index, |
58 | uint64_t value); |
59 | static void set_refcount_ro6(void *refcount_array, uint64_t index, |
60 | uint64_t value); |
61 | |
62 | |
63 | static Qcow2GetRefcountFunc *const get_refcount_funcs[] = { |
64 | &get_refcount_ro0, |
65 | &get_refcount_ro1, |
66 | &get_refcount_ro2, |
67 | &get_refcount_ro3, |
68 | &get_refcount_ro4, |
69 | &get_refcount_ro5, |
70 | &get_refcount_ro6 |
71 | }; |
72 | |
73 | static Qcow2SetRefcountFunc *const set_refcount_funcs[] = { |
74 | &set_refcount_ro0, |
75 | &set_refcount_ro1, |
76 | &set_refcount_ro2, |
77 | &set_refcount_ro3, |
78 | &set_refcount_ro4, |
79 | &set_refcount_ro5, |
80 | &set_refcount_ro6 |
81 | }; |
82 | |
83 | |
84 | /*********************************************************/ |
85 | /* refcount handling */ |
86 | |
87 | static void update_max_refcount_table_index(BDRVQcow2State *s) |
88 | { |
89 | unsigned i = s->refcount_table_size - 1; |
90 | while (i > 0 && (s->refcount_table[i] & REFT_OFFSET_MASK) == 0) { |
91 | i--; |
92 | } |
93 | /* Set s->max_refcount_table_index to the index of the last used entry */ |
94 | s->max_refcount_table_index = i; |
95 | } |
96 | |
97 | int qcow2_refcount_init(BlockDriverState *bs) |
98 | { |
99 | BDRVQcow2State *s = bs->opaque; |
100 | unsigned int refcount_table_size2, i; |
101 | int ret; |
102 | |
103 | assert(s->refcount_order >= 0 && s->refcount_order <= 6); |
104 | |
105 | s->get_refcount = get_refcount_funcs[s->refcount_order]; |
106 | s->set_refcount = set_refcount_funcs[s->refcount_order]; |
107 | |
108 | assert(s->refcount_table_size <= INT_MAX / sizeof(uint64_t)); |
109 | refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); |
110 | s->refcount_table = g_try_malloc(refcount_table_size2); |
111 | |
112 | if (s->refcount_table_size > 0) { |
113 | if (s->refcount_table == NULL) { |
114 | ret = -ENOMEM; |
115 | goto fail; |
116 | } |
117 | BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD); |
118 | ret = bdrv_pread(bs->file, s->refcount_table_offset, |
119 | s->refcount_table, refcount_table_size2); |
120 | if (ret < 0) { |
121 | goto fail; |
122 | } |
123 | for(i = 0; i < s->refcount_table_size; i++) |
124 | be64_to_cpus(&s->refcount_table[i]); |
125 | update_max_refcount_table_index(s); |
126 | } |
127 | return 0; |
128 | fail: |
129 | return ret; |
130 | } |
131 | |
132 | void qcow2_refcount_close(BlockDriverState *bs) |
133 | { |
134 | BDRVQcow2State *s = bs->opaque; |
135 | g_free(s->refcount_table); |
136 | } |
137 | |
138 | |
139 | static uint64_t get_refcount_ro0(const void *refcount_array, uint64_t index) |
140 | { |
141 | return (((const uint8_t *)refcount_array)[index / 8] >> (index % 8)) & 0x1; |
142 | } |
143 | |
144 | static void set_refcount_ro0(void *refcount_array, uint64_t index, |
145 | uint64_t value) |
146 | { |
147 | assert(!(value >> 1)); |
148 | ((uint8_t *)refcount_array)[index / 8] &= ~(0x1 << (index % 8)); |
149 | ((uint8_t *)refcount_array)[index / 8] |= value << (index % 8); |
150 | } |
151 | |
152 | static uint64_t get_refcount_ro1(const void *refcount_array, uint64_t index) |
153 | { |
154 | return (((const uint8_t *)refcount_array)[index / 4] >> (2 * (index % 4))) |
155 | & 0x3; |
156 | } |
157 | |
158 | static void set_refcount_ro1(void *refcount_array, uint64_t index, |
159 | uint64_t value) |
160 | { |
161 | assert(!(value >> 2)); |
162 | ((uint8_t *)refcount_array)[index / 4] &= ~(0x3 << (2 * (index % 4))); |
163 | ((uint8_t *)refcount_array)[index / 4] |= value << (2 * (index % 4)); |
164 | } |
165 | |
166 | static uint64_t get_refcount_ro2(const void *refcount_array, uint64_t index) |
167 | { |
168 | return (((const uint8_t *)refcount_array)[index / 2] >> (4 * (index % 2))) |
169 | & 0xf; |
170 | } |
171 | |
172 | static void set_refcount_ro2(void *refcount_array, uint64_t index, |
173 | uint64_t value) |
174 | { |
175 | assert(!(value >> 4)); |
176 | ((uint8_t *)refcount_array)[index / 2] &= ~(0xf << (4 * (index % 2))); |
177 | ((uint8_t *)refcount_array)[index / 2] |= value << (4 * (index % 2)); |
178 | } |
179 | |
180 | static uint64_t get_refcount_ro3(const void *refcount_array, uint64_t index) |
181 | { |
182 | return ((const uint8_t *)refcount_array)[index]; |
183 | } |
184 | |
185 | static void set_refcount_ro3(void *refcount_array, uint64_t index, |
186 | uint64_t value) |
187 | { |
188 | assert(!(value >> 8)); |
189 | ((uint8_t *)refcount_array)[index] = value; |
190 | } |
191 | |
192 | static uint64_t get_refcount_ro4(const void *refcount_array, uint64_t index) |
193 | { |
194 | return be16_to_cpu(((const uint16_t *)refcount_array)[index]); |
195 | } |
196 | |
197 | static void set_refcount_ro4(void *refcount_array, uint64_t index, |
198 | uint64_t value) |
199 | { |
200 | assert(!(value >> 16)); |
201 | ((uint16_t *)refcount_array)[index] = cpu_to_be16(value); |
202 | } |
203 | |
204 | static uint64_t get_refcount_ro5(const void *refcount_array, uint64_t index) |
205 | { |
206 | return be32_to_cpu(((const uint32_t *)refcount_array)[index]); |
207 | } |
208 | |
209 | static void set_refcount_ro5(void *refcount_array, uint64_t index, |
210 | uint64_t value) |
211 | { |
212 | assert(!(value >> 32)); |
213 | ((uint32_t *)refcount_array)[index] = cpu_to_be32(value); |
214 | } |
215 | |
216 | static uint64_t get_refcount_ro6(const void *refcount_array, uint64_t index) |
217 | { |
218 | return be64_to_cpu(((const uint64_t *)refcount_array)[index]); |
219 | } |
220 | |
221 | static void set_refcount_ro6(void *refcount_array, uint64_t index, |
222 | uint64_t value) |
223 | { |
224 | ((uint64_t *)refcount_array)[index] = cpu_to_be64(value); |
225 | } |
226 | |
227 | |
228 | static int load_refcount_block(BlockDriverState *bs, |
229 | int64_t refcount_block_offset, |
230 | void **refcount_block) |
231 | { |
232 | BDRVQcow2State *s = bs->opaque; |
233 | |
234 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD); |
235 | return qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, |
236 | refcount_block); |
237 | } |
238 | |
239 | /* |
240 | * Retrieves the refcount of the cluster given by its index and stores it in |
241 | * *refcount. Returns 0 on success and -errno on failure. |
242 | */ |
243 | int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index, |
244 | uint64_t *refcount) |
245 | { |
246 | BDRVQcow2State *s = bs->opaque; |
247 | uint64_t refcount_table_index, block_index; |
248 | int64_t refcount_block_offset; |
249 | int ret; |
250 | void *refcount_block; |
251 | |
252 | refcount_table_index = cluster_index >> s->refcount_block_bits; |
253 | if (refcount_table_index >= s->refcount_table_size) { |
254 | *refcount = 0; |
255 | return 0; |
256 | } |
257 | refcount_block_offset = |
258 | s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK; |
259 | if (!refcount_block_offset) { |
260 | *refcount = 0; |
261 | return 0; |
262 | } |
263 | |
264 | if (offset_into_cluster(s, refcount_block_offset)) { |
265 | qcow2_signal_corruption(bs, true, -1, -1, "Refblock offset %#" PRIx64 |
266 | " unaligned (reftable index: %#" PRIx64 ")" , |
267 | refcount_block_offset, refcount_table_index); |
268 | return -EIO; |
269 | } |
270 | |
271 | ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, |
272 | &refcount_block); |
273 | if (ret < 0) { |
274 | return ret; |
275 | } |
276 | |
277 | block_index = cluster_index & (s->refcount_block_size - 1); |
278 | *refcount = s->get_refcount(refcount_block, block_index); |
279 | |
280 | qcow2_cache_put(s->refcount_block_cache, &refcount_block); |
281 | |
282 | return 0; |
283 | } |
284 | |
285 | /* Checks if two offsets are described by the same refcount block */ |
286 | static int in_same_refcount_block(BDRVQcow2State *s, uint64_t offset_a, |
287 | uint64_t offset_b) |
288 | { |
289 | uint64_t block_a = offset_a >> (s->cluster_bits + s->refcount_block_bits); |
290 | uint64_t block_b = offset_b >> (s->cluster_bits + s->refcount_block_bits); |
291 | |
292 | return (block_a == block_b); |
293 | } |
294 | |
295 | /* |
296 | * Loads a refcount block. If it doesn't exist yet, it is allocated first |
297 | * (including growing the refcount table if needed). |
298 | * |
299 | * Returns 0 on success or -errno in error case |
300 | */ |
301 | static int alloc_refcount_block(BlockDriverState *bs, |
302 | int64_t cluster_index, void **refcount_block) |
303 | { |
304 | BDRVQcow2State *s = bs->opaque; |
305 | unsigned int refcount_table_index; |
306 | int64_t ret; |
307 | |
308 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); |
309 | |
310 | /* Find the refcount block for the given cluster */ |
311 | refcount_table_index = cluster_index >> s->refcount_block_bits; |
312 | |
313 | if (refcount_table_index < s->refcount_table_size) { |
314 | |
315 | uint64_t refcount_block_offset = |
316 | s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK; |
317 | |
318 | /* If it's already there, we're done */ |
319 | if (refcount_block_offset) { |
320 | if (offset_into_cluster(s, refcount_block_offset)) { |
321 | qcow2_signal_corruption(bs, true, -1, -1, "Refblock offset %#" |
322 | PRIx64 " unaligned (reftable index: " |
323 | "%#x)" , refcount_block_offset, |
324 | refcount_table_index); |
325 | return -EIO; |
326 | } |
327 | |
328 | return load_refcount_block(bs, refcount_block_offset, |
329 | refcount_block); |
330 | } |
331 | } |
332 | |
333 | /* |
334 | * If we came here, we need to allocate something. Something is at least |
335 | * a cluster for the new refcount block. It may also include a new refcount |
336 | * table if the old refcount table is too small. |
337 | * |
338 | * Note that allocating clusters here needs some special care: |
339 | * |
340 | * - We can't use the normal qcow2_alloc_clusters(), it would try to |
341 | * increase the refcount and very likely we would end up with an endless |
342 | * recursion. Instead we must place the refcount blocks in a way that |
343 | * they can describe them themselves. |
344 | * |
345 | * - We need to consider that at this point we are inside update_refcounts |
346 | * and potentially doing an initial refcount increase. This means that |
347 | * some clusters have already been allocated by the caller, but their |
348 | * refcount isn't accurate yet. If we allocate clusters for metadata, we |
349 | * need to return -EAGAIN to signal the caller that it needs to restart |
350 | * the search for free clusters. |
351 | * |
352 | * - alloc_clusters_noref and qcow2_free_clusters may load a different |
353 | * refcount block into the cache |
354 | */ |
355 | |
356 | *refcount_block = NULL; |
357 | |
358 | /* We write to the refcount table, so we might depend on L2 tables */ |
359 | ret = qcow2_cache_flush(bs, s->l2_table_cache); |
360 | if (ret < 0) { |
361 | return ret; |
362 | } |
363 | |
364 | /* Allocate the refcount block itself and mark it as used */ |
365 | int64_t new_block = alloc_clusters_noref(bs, s->cluster_size, INT64_MAX); |
366 | if (new_block < 0) { |
367 | return new_block; |
368 | } |
369 | |
370 | /* The offset must fit in the offset field of the refcount table entry */ |
371 | assert((new_block & REFT_OFFSET_MASK) == new_block); |
372 | |
373 | /* If we're allocating the block at offset 0 then something is wrong */ |
374 | if (new_block == 0) { |
375 | qcow2_signal_corruption(bs, true, -1, -1, "Preventing invalid " |
376 | "allocation of refcount block at offset 0" ); |
377 | return -EIO; |
378 | } |
379 | |
380 | #ifdef DEBUG_ALLOC2 |
381 | fprintf(stderr, "qcow2: Allocate refcount block %d for %" PRIx64 |
382 | " at %" PRIx64 "\n" , |
383 | refcount_table_index, cluster_index << s->cluster_bits, new_block); |
384 | #endif |
385 | |
386 | if (in_same_refcount_block(s, new_block, cluster_index << s->cluster_bits)) { |
387 | /* Zero the new refcount block before updating it */ |
388 | ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
389 | refcount_block); |
390 | if (ret < 0) { |
391 | goto fail; |
392 | } |
393 | |
394 | memset(*refcount_block, 0, s->cluster_size); |
395 | |
396 | /* The block describes itself, need to update the cache */ |
397 | int block_index = (new_block >> s->cluster_bits) & |
398 | (s->refcount_block_size - 1); |
399 | s->set_refcount(*refcount_block, block_index, 1); |
400 | } else { |
401 | /* Described somewhere else. This can recurse at most twice before we |
402 | * arrive at a block that describes itself. */ |
403 | ret = update_refcount(bs, new_block, s->cluster_size, 1, false, |
404 | QCOW2_DISCARD_NEVER); |
405 | if (ret < 0) { |
406 | goto fail; |
407 | } |
408 | |
409 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
410 | if (ret < 0) { |
411 | goto fail; |
412 | } |
413 | |
414 | /* Initialize the new refcount block only after updating its refcount, |
415 | * update_refcount uses the refcount cache itself */ |
416 | ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
417 | refcount_block); |
418 | if (ret < 0) { |
419 | goto fail; |
420 | } |
421 | |
422 | memset(*refcount_block, 0, s->cluster_size); |
423 | } |
424 | |
425 | /* Now the new refcount block needs to be written to disk */ |
426 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE); |
427 | qcow2_cache_entry_mark_dirty(s->refcount_block_cache, *refcount_block); |
428 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
429 | if (ret < 0) { |
430 | goto fail; |
431 | } |
432 | |
433 | /* If the refcount table is big enough, just hook the block up there */ |
434 | if (refcount_table_index < s->refcount_table_size) { |
435 | uint64_t data64 = cpu_to_be64(new_block); |
436 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_HOOKUP); |
437 | ret = bdrv_pwrite_sync(bs->file, |
438 | s->refcount_table_offset + refcount_table_index * sizeof(uint64_t), |
439 | &data64, sizeof(data64)); |
440 | if (ret < 0) { |
441 | goto fail; |
442 | } |
443 | |
444 | s->refcount_table[refcount_table_index] = new_block; |
445 | /* If there's a hole in s->refcount_table then it can happen |
446 | * that refcount_table_index < s->max_refcount_table_index */ |
447 | s->max_refcount_table_index = |
448 | MAX(s->max_refcount_table_index, refcount_table_index); |
449 | |
450 | /* The new refcount block may be where the caller intended to put its |
451 | * data, so let it restart the search. */ |
452 | return -EAGAIN; |
453 | } |
454 | |
455 | qcow2_cache_put(s->refcount_block_cache, refcount_block); |
456 | |
457 | /* |
458 | * If we come here, we need to grow the refcount table. Again, a new |
459 | * refcount table needs some space and we can't simply allocate to avoid |
460 | * endless recursion. |
461 | * |
462 | * Therefore let's grab new refcount blocks at the end of the image, which |
463 | * will describe themselves and the new refcount table. This way we can |
464 | * reference them only in the new table and do the switch to the new |
465 | * refcount table at once without producing an inconsistent state in |
466 | * between. |
467 | */ |
468 | BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW); |
469 | |
470 | /* Calculate the number of refcount blocks needed so far; this will be the |
471 | * basis for calculating the index of the first cluster used for the |
472 | * self-describing refcount structures which we are about to create. |
473 | * |
474 | * Because we reached this point, there cannot be any refcount entries for |
475 | * cluster_index or higher indices yet. However, because new_block has been |
476 | * allocated to describe that cluster (and it will assume this role later |
477 | * on), we cannot use that index; also, new_block may actually have a higher |
478 | * cluster index than cluster_index, so it needs to be taken into account |
479 | * here (and 1 needs to be added to its value because that cluster is used). |
480 | */ |
481 | uint64_t blocks_used = DIV_ROUND_UP(MAX(cluster_index + 1, |
482 | (new_block >> s->cluster_bits) + 1), |
483 | s->refcount_block_size); |
484 | |
485 | /* Create the new refcount table and blocks */ |
486 | uint64_t meta_offset = (blocks_used * s->refcount_block_size) * |
487 | s->cluster_size; |
488 | |
489 | ret = qcow2_refcount_area(bs, meta_offset, 0, false, |
490 | refcount_table_index, new_block); |
491 | if (ret < 0) { |
492 | return ret; |
493 | } |
494 | |
495 | ret = load_refcount_block(bs, new_block, refcount_block); |
496 | if (ret < 0) { |
497 | return ret; |
498 | } |
499 | |
500 | /* If we were trying to do the initial refcount update for some cluster |
501 | * allocation, we might have used the same clusters to store newly |
502 | * allocated metadata. Make the caller search some new space. */ |
503 | return -EAGAIN; |
504 | |
505 | fail: |
506 | if (*refcount_block != NULL) { |
507 | qcow2_cache_put(s->refcount_block_cache, refcount_block); |
508 | } |
509 | return ret; |
510 | } |
511 | |
512 | /* |
513 | * Starting at @start_offset, this function creates new self-covering refcount |
514 | * structures: A new refcount table and refcount blocks which cover all of |
515 | * themselves, and a number of @additional_clusters beyond their end. |
516 | * @start_offset must be at the end of the image file, that is, there must be |
517 | * only empty space beyond it. |
518 | * If @exact_size is false, the refcount table will have 50 % more entries than |
519 | * necessary so it will not need to grow again soon. |
520 | * If @new_refblock_offset is not zero, it contains the offset of a refcount |
521 | * block that should be entered into the new refcount table at index |
522 | * @new_refblock_index. |
523 | * |
524 | * Returns: The offset after the new refcount structures (i.e. where the |
525 | * @additional_clusters may be placed) on success, -errno on error. |
526 | */ |
527 | int64_t qcow2_refcount_area(BlockDriverState *bs, uint64_t start_offset, |
528 | uint64_t additional_clusters, bool exact_size, |
529 | int new_refblock_index, |
530 | uint64_t new_refblock_offset) |
531 | { |
532 | BDRVQcow2State *s = bs->opaque; |
533 | uint64_t total_refblock_count_u64, additional_refblock_count; |
534 | int total_refblock_count, table_size, area_reftable_index, table_clusters; |
535 | int i; |
536 | uint64_t table_offset, block_offset, end_offset; |
537 | int ret; |
538 | uint64_t *new_table; |
539 | |
540 | assert(!(start_offset % s->cluster_size)); |
541 | |
542 | qcow2_refcount_metadata_size(start_offset / s->cluster_size + |
543 | additional_clusters, |
544 | s->cluster_size, s->refcount_order, |
545 | !exact_size, &total_refblock_count_u64); |
546 | if (total_refblock_count_u64 > QCOW_MAX_REFTABLE_SIZE) { |
547 | return -EFBIG; |
548 | } |
549 | total_refblock_count = total_refblock_count_u64; |
550 | |
551 | /* Index in the refcount table of the first refcount block to cover the area |
552 | * of refcount structures we are about to create; we know that |
553 | * @total_refblock_count can cover @start_offset, so this will definitely |
554 | * fit into an int. */ |
555 | area_reftable_index = (start_offset / s->cluster_size) / |
556 | s->refcount_block_size; |
557 | |
558 | if (exact_size) { |
559 | table_size = total_refblock_count; |
560 | } else { |
561 | table_size = total_refblock_count + |
562 | DIV_ROUND_UP(total_refblock_count, 2); |
563 | } |
564 | /* The qcow2 file can only store the reftable size in number of clusters */ |
565 | table_size = ROUND_UP(table_size, s->cluster_size / sizeof(uint64_t)); |
566 | table_clusters = (table_size * sizeof(uint64_t)) / s->cluster_size; |
567 | |
568 | if (table_size > QCOW_MAX_REFTABLE_SIZE) { |
569 | return -EFBIG; |
570 | } |
571 | |
572 | new_table = g_try_new0(uint64_t, table_size); |
573 | |
574 | assert(table_size > 0); |
575 | if (new_table == NULL) { |
576 | ret = -ENOMEM; |
577 | goto fail; |
578 | } |
579 | |
580 | /* Fill the new refcount table */ |
581 | if (table_size > s->max_refcount_table_index) { |
582 | /* We're actually growing the reftable */ |
583 | memcpy(new_table, s->refcount_table, |
584 | (s->max_refcount_table_index + 1) * sizeof(uint64_t)); |
585 | } else { |
586 | /* Improbable case: We're shrinking the reftable. However, the caller |
587 | * has assured us that there is only empty space beyond @start_offset, |
588 | * so we can simply drop all of the refblocks that won't fit into the |
589 | * new reftable. */ |
590 | memcpy(new_table, s->refcount_table, table_size * sizeof(uint64_t)); |
591 | } |
592 | |
593 | if (new_refblock_offset) { |
594 | assert(new_refblock_index < total_refblock_count); |
595 | new_table[new_refblock_index] = new_refblock_offset; |
596 | } |
597 | |
598 | /* Count how many new refblocks we have to create */ |
599 | additional_refblock_count = 0; |
600 | for (i = area_reftable_index; i < total_refblock_count; i++) { |
601 | if (!new_table[i]) { |
602 | additional_refblock_count++; |
603 | } |
604 | } |
605 | |
606 | table_offset = start_offset + additional_refblock_count * s->cluster_size; |
607 | end_offset = table_offset + table_clusters * s->cluster_size; |
608 | |
609 | /* Fill the refcount blocks, and create new ones, if necessary */ |
610 | block_offset = start_offset; |
611 | for (i = area_reftable_index; i < total_refblock_count; i++) { |
612 | void *refblock_data; |
613 | uint64_t first_offset_covered; |
614 | |
615 | /* Reuse an existing refblock if possible, create a new one otherwise */ |
616 | if (new_table[i]) { |
617 | ret = qcow2_cache_get(bs, s->refcount_block_cache, new_table[i], |
618 | &refblock_data); |
619 | if (ret < 0) { |
620 | goto fail; |
621 | } |
622 | } else { |
623 | ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, |
624 | block_offset, &refblock_data); |
625 | if (ret < 0) { |
626 | goto fail; |
627 | } |
628 | memset(refblock_data, 0, s->cluster_size); |
629 | qcow2_cache_entry_mark_dirty(s->refcount_block_cache, |
630 | refblock_data); |
631 | |
632 | new_table[i] = block_offset; |
633 | block_offset += s->cluster_size; |
634 | } |
635 | |
636 | /* First host offset covered by this refblock */ |
637 | first_offset_covered = (uint64_t)i * s->refcount_block_size * |
638 | s->cluster_size; |
639 | if (first_offset_covered < end_offset) { |
640 | int j, end_index; |
641 | |
642 | /* Set the refcount of all of the new refcount structures to 1 */ |
643 | |
644 | if (first_offset_covered < start_offset) { |
645 | assert(i == area_reftable_index); |
646 | j = (start_offset - first_offset_covered) / s->cluster_size; |
647 | assert(j < s->refcount_block_size); |
648 | } else { |
649 | j = 0; |
650 | } |
651 | |
652 | end_index = MIN((end_offset - first_offset_covered) / |
653 | s->cluster_size, |
654 | s->refcount_block_size); |
655 | |
656 | for (; j < end_index; j++) { |
657 | /* The caller guaranteed us this space would be empty */ |
658 | assert(s->get_refcount(refblock_data, j) == 0); |
659 | s->set_refcount(refblock_data, j, 1); |
660 | } |
661 | |
662 | qcow2_cache_entry_mark_dirty(s->refcount_block_cache, |
663 | refblock_data); |
664 | } |
665 | |
666 | qcow2_cache_put(s->refcount_block_cache, &refblock_data); |
667 | } |
668 | |
669 | assert(block_offset == table_offset); |
670 | |
671 | /* Write refcount blocks to disk */ |
672 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS); |
673 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
674 | if (ret < 0) { |
675 | goto fail; |
676 | } |
677 | |
678 | /* Write refcount table to disk */ |
679 | for (i = 0; i < total_refblock_count; i++) { |
680 | cpu_to_be64s(&new_table[i]); |
681 | } |
682 | |
683 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE); |
684 | ret = bdrv_pwrite_sync(bs->file, table_offset, new_table, |
685 | table_size * sizeof(uint64_t)); |
686 | if (ret < 0) { |
687 | goto fail; |
688 | } |
689 | |
690 | for (i = 0; i < total_refblock_count; i++) { |
691 | be64_to_cpus(&new_table[i]); |
692 | } |
693 | |
694 | /* Hook up the new refcount table in the qcow2 header */ |
695 | struct QEMU_PACKED { |
696 | uint64_t d64; |
697 | uint32_t d32; |
698 | } data; |
699 | data.d64 = cpu_to_be64(table_offset); |
700 | data.d32 = cpu_to_be32(table_clusters); |
701 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE); |
702 | ret = bdrv_pwrite_sync(bs->file, |
703 | offsetof(QCowHeader, refcount_table_offset), |
704 | &data, sizeof(data)); |
705 | if (ret < 0) { |
706 | goto fail; |
707 | } |
708 | |
709 | /* And switch it in memory */ |
710 | uint64_t old_table_offset = s->refcount_table_offset; |
711 | uint64_t old_table_size = s->refcount_table_size; |
712 | |
713 | g_free(s->refcount_table); |
714 | s->refcount_table = new_table; |
715 | s->refcount_table_size = table_size; |
716 | s->refcount_table_offset = table_offset; |
717 | update_max_refcount_table_index(s); |
718 | |
719 | /* Free old table. */ |
720 | qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t), |
721 | QCOW2_DISCARD_OTHER); |
722 | |
723 | return end_offset; |
724 | |
725 | fail: |
726 | g_free(new_table); |
727 | return ret; |
728 | } |
729 | |
730 | void qcow2_process_discards(BlockDriverState *bs, int ret) |
731 | { |
732 | BDRVQcow2State *s = bs->opaque; |
733 | Qcow2DiscardRegion *d, *next; |
734 | |
735 | QTAILQ_FOREACH_SAFE(d, &s->discards, next, next) { |
736 | QTAILQ_REMOVE(&s->discards, d, next); |
737 | |
738 | /* Discard is optional, ignore the return value */ |
739 | if (ret >= 0) { |
740 | int r2 = bdrv_pdiscard(bs->file, d->offset, d->bytes); |
741 | if (r2 < 0) { |
742 | trace_qcow2_process_discards_failed_region(d->offset, d->bytes, |
743 | r2); |
744 | } |
745 | } |
746 | |
747 | g_free(d); |
748 | } |
749 | } |
750 | |
751 | static void update_refcount_discard(BlockDriverState *bs, |
752 | uint64_t offset, uint64_t length) |
753 | { |
754 | BDRVQcow2State *s = bs->opaque; |
755 | Qcow2DiscardRegion *d, *p, *next; |
756 | |
757 | QTAILQ_FOREACH(d, &s->discards, next) { |
758 | uint64_t new_start = MIN(offset, d->offset); |
759 | uint64_t new_end = MAX(offset + length, d->offset + d->bytes); |
760 | |
761 | if (new_end - new_start <= length + d->bytes) { |
762 | /* There can't be any overlap, areas ending up here have no |
763 | * references any more and therefore shouldn't get freed another |
764 | * time. */ |
765 | assert(d->bytes + length == new_end - new_start); |
766 | d->offset = new_start; |
767 | d->bytes = new_end - new_start; |
768 | goto found; |
769 | } |
770 | } |
771 | |
772 | d = g_malloc(sizeof(*d)); |
773 | *d = (Qcow2DiscardRegion) { |
774 | .bs = bs, |
775 | .offset = offset, |
776 | .bytes = length, |
777 | }; |
778 | QTAILQ_INSERT_TAIL(&s->discards, d, next); |
779 | |
780 | found: |
781 | /* Merge discard requests if they are adjacent now */ |
782 | QTAILQ_FOREACH_SAFE(p, &s->discards, next, next) { |
783 | if (p == d |
784 | || p->offset > d->offset + d->bytes |
785 | || d->offset > p->offset + p->bytes) |
786 | { |
787 | continue; |
788 | } |
789 | |
790 | /* Still no overlap possible */ |
791 | assert(p->offset == d->offset + d->bytes |
792 | || d->offset == p->offset + p->bytes); |
793 | |
794 | QTAILQ_REMOVE(&s->discards, p, next); |
795 | d->offset = MIN(d->offset, p->offset); |
796 | d->bytes += p->bytes; |
797 | g_free(p); |
798 | } |
799 | } |
800 | |
801 | /* XXX: cache several refcount block clusters ? */ |
802 | /* @addend is the absolute value of the addend; if @decrease is set, @addend |
803 | * will be subtracted from the current refcount, otherwise it will be added */ |
804 | static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
805 | int64_t offset, |
806 | int64_t length, |
807 | uint64_t addend, |
808 | bool decrease, |
809 | enum qcow2_discard_type type) |
810 | { |
811 | BDRVQcow2State *s = bs->opaque; |
812 | int64_t start, last, cluster_offset; |
813 | void *refcount_block = NULL; |
814 | int64_t old_table_index = -1; |
815 | int ret; |
816 | |
817 | #ifdef DEBUG_ALLOC2 |
818 | fprintf(stderr, "update_refcount: offset=%" PRId64 " size=%" PRId64 |
819 | " addend=%s%" PRIu64 "\n" , offset, length, decrease ? "-" : "" , |
820 | addend); |
821 | #endif |
822 | if (length < 0) { |
823 | return -EINVAL; |
824 | } else if (length == 0) { |
825 | return 0; |
826 | } |
827 | |
828 | if (decrease) { |
829 | qcow2_cache_set_dependency(bs, s->refcount_block_cache, |
830 | s->l2_table_cache); |
831 | } |
832 | |
833 | start = start_of_cluster(s, offset); |
834 | last = start_of_cluster(s, offset + length - 1); |
835 | for(cluster_offset = start; cluster_offset <= last; |
836 | cluster_offset += s->cluster_size) |
837 | { |
838 | int block_index; |
839 | uint64_t refcount; |
840 | int64_t cluster_index = cluster_offset >> s->cluster_bits; |
841 | int64_t table_index = cluster_index >> s->refcount_block_bits; |
842 | |
843 | /* Load the refcount block and allocate it if needed */ |
844 | if (table_index != old_table_index) { |
845 | if (refcount_block) { |
846 | qcow2_cache_put(s->refcount_block_cache, &refcount_block); |
847 | } |
848 | ret = alloc_refcount_block(bs, cluster_index, &refcount_block); |
849 | /* If the caller needs to restart the search for free clusters, |
850 | * try the same ones first to see if they're still free. */ |
851 | if (ret == -EAGAIN) { |
852 | if (s->free_cluster_index > (start >> s->cluster_bits)) { |
853 | s->free_cluster_index = (start >> s->cluster_bits); |
854 | } |
855 | } |
856 | if (ret < 0) { |
857 | goto fail; |
858 | } |
859 | } |
860 | old_table_index = table_index; |
861 | |
862 | qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refcount_block); |
863 | |
864 | /* we can update the count and save it */ |
865 | block_index = cluster_index & (s->refcount_block_size - 1); |
866 | |
867 | refcount = s->get_refcount(refcount_block, block_index); |
868 | if (decrease ? (refcount - addend > refcount) |
869 | : (refcount + addend < refcount || |
870 | refcount + addend > s->refcount_max)) |
871 | { |
872 | ret = -EINVAL; |
873 | goto fail; |
874 | } |
875 | if (decrease) { |
876 | refcount -= addend; |
877 | } else { |
878 | refcount += addend; |
879 | } |
880 | if (refcount == 0 && cluster_index < s->free_cluster_index) { |
881 | s->free_cluster_index = cluster_index; |
882 | } |
883 | s->set_refcount(refcount_block, block_index, refcount); |
884 | |
885 | if (refcount == 0) { |
886 | void *table; |
887 | |
888 | table = qcow2_cache_is_table_offset(s->refcount_block_cache, |
889 | offset); |
890 | if (table != NULL) { |
891 | qcow2_cache_put(s->refcount_block_cache, &refcount_block); |
892 | qcow2_cache_discard(s->refcount_block_cache, table); |
893 | } |
894 | |
895 | table = qcow2_cache_is_table_offset(s->l2_table_cache, offset); |
896 | if (table != NULL) { |
897 | qcow2_cache_discard(s->l2_table_cache, table); |
898 | } |
899 | |
900 | if (s->discard_passthrough[type]) { |
901 | update_refcount_discard(bs, cluster_offset, s->cluster_size); |
902 | } |
903 | } |
904 | } |
905 | |
906 | ret = 0; |
907 | fail: |
908 | if (!s->cache_discards) { |
909 | qcow2_process_discards(bs, ret); |
910 | } |
911 | |
912 | /* Write last changed block to disk */ |
913 | if (refcount_block) { |
914 | qcow2_cache_put(s->refcount_block_cache, &refcount_block); |
915 | } |
916 | |
917 | /* |
918 | * Try do undo any updates if an error is returned (This may succeed in |
919 | * some cases like ENOSPC for allocating a new refcount block) |
920 | */ |
921 | if (ret < 0) { |
922 | int dummy; |
923 | dummy = update_refcount(bs, offset, cluster_offset - offset, addend, |
924 | !decrease, QCOW2_DISCARD_NEVER); |
925 | (void)dummy; |
926 | } |
927 | |
928 | return ret; |
929 | } |
930 | |
931 | /* |
932 | * Increases or decreases the refcount of a given cluster. |
933 | * |
934 | * @addend is the absolute value of the addend; if @decrease is set, @addend |
935 | * will be subtracted from the current refcount, otherwise it will be added. |
936 | * |
937 | * On success 0 is returned; on failure -errno is returned. |
938 | */ |
939 | int qcow2_update_cluster_refcount(BlockDriverState *bs, |
940 | int64_t cluster_index, |
941 | uint64_t addend, bool decrease, |
942 | enum qcow2_discard_type type) |
943 | { |
944 | BDRVQcow2State *s = bs->opaque; |
945 | int ret; |
946 | |
947 | ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend, |
948 | decrease, type); |
949 | if (ret < 0) { |
950 | return ret; |
951 | } |
952 | |
953 | return 0; |
954 | } |
955 | |
956 | |
957 | |
958 | /*********************************************************/ |
959 | /* cluster allocation functions */ |
960 | |
961 | |
962 | |
963 | /* return < 0 if error */ |
964 | static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size, |
965 | uint64_t max) |
966 | { |
967 | BDRVQcow2State *s = bs->opaque; |
968 | uint64_t i, nb_clusters, refcount; |
969 | int ret; |
970 | |
971 | /* We can't allocate clusters if they may still be queued for discard. */ |
972 | if (s->cache_discards) { |
973 | qcow2_process_discards(bs, 0); |
974 | } |
975 | |
976 | nb_clusters = size_to_clusters(s, size); |
977 | retry: |
978 | for(i = 0; i < nb_clusters; i++) { |
979 | uint64_t next_cluster_index = s->free_cluster_index++; |
980 | ret = qcow2_get_refcount(bs, next_cluster_index, &refcount); |
981 | |
982 | if (ret < 0) { |
983 | return ret; |
984 | } else if (refcount != 0) { |
985 | goto retry; |
986 | } |
987 | } |
988 | |
989 | /* Make sure that all offsets in the "allocated" range are representable |
990 | * in the requested max */ |
991 | if (s->free_cluster_index > 0 && |
992 | s->free_cluster_index - 1 > (max >> s->cluster_bits)) |
993 | { |
994 | return -EFBIG; |
995 | } |
996 | |
997 | #ifdef DEBUG_ALLOC2 |
998 | fprintf(stderr, "alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n" , |
999 | size, |
1000 | (s->free_cluster_index - nb_clusters) << s->cluster_bits); |
1001 | #endif |
1002 | return (s->free_cluster_index - nb_clusters) << s->cluster_bits; |
1003 | } |
1004 | |
1005 | int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size) |
1006 | { |
1007 | int64_t offset; |
1008 | int ret; |
1009 | |
1010 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); |
1011 | do { |
1012 | offset = alloc_clusters_noref(bs, size, QCOW_MAX_CLUSTER_OFFSET); |
1013 | if (offset < 0) { |
1014 | return offset; |
1015 | } |
1016 | |
1017 | ret = update_refcount(bs, offset, size, 1, false, QCOW2_DISCARD_NEVER); |
1018 | } while (ret == -EAGAIN); |
1019 | |
1020 | if (ret < 0) { |
1021 | return ret; |
1022 | } |
1023 | |
1024 | return offset; |
1025 | } |
1026 | |
1027 | int64_t qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, |
1028 | int64_t nb_clusters) |
1029 | { |
1030 | BDRVQcow2State *s = bs->opaque; |
1031 | uint64_t cluster_index, refcount; |
1032 | uint64_t i; |
1033 | int ret; |
1034 | |
1035 | assert(nb_clusters >= 0); |
1036 | if (nb_clusters == 0) { |
1037 | return 0; |
1038 | } |
1039 | |
1040 | do { |
1041 | /* Check how many clusters there are free */ |
1042 | cluster_index = offset >> s->cluster_bits; |
1043 | for(i = 0; i < nb_clusters; i++) { |
1044 | ret = qcow2_get_refcount(bs, cluster_index++, &refcount); |
1045 | if (ret < 0) { |
1046 | return ret; |
1047 | } else if (refcount != 0) { |
1048 | break; |
1049 | } |
1050 | } |
1051 | |
1052 | /* And then allocate them */ |
1053 | ret = update_refcount(bs, offset, i << s->cluster_bits, 1, false, |
1054 | QCOW2_DISCARD_NEVER); |
1055 | } while (ret == -EAGAIN); |
1056 | |
1057 | if (ret < 0) { |
1058 | return ret; |
1059 | } |
1060 | |
1061 | return i; |
1062 | } |
1063 | |
1064 | /* only used to allocate compressed sectors. We try to allocate |
1065 | contiguous sectors. size must be <= cluster_size */ |
1066 | int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) |
1067 | { |
1068 | BDRVQcow2State *s = bs->opaque; |
1069 | int64_t offset; |
1070 | size_t free_in_cluster; |
1071 | int ret; |
1072 | |
1073 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); |
1074 | assert(size > 0 && size <= s->cluster_size); |
1075 | assert(!s->free_byte_offset || offset_into_cluster(s, s->free_byte_offset)); |
1076 | |
1077 | offset = s->free_byte_offset; |
1078 | |
1079 | if (offset) { |
1080 | uint64_t refcount; |
1081 | ret = qcow2_get_refcount(bs, offset >> s->cluster_bits, &refcount); |
1082 | if (ret < 0) { |
1083 | return ret; |
1084 | } |
1085 | |
1086 | if (refcount == s->refcount_max) { |
1087 | offset = 0; |
1088 | } |
1089 | } |
1090 | |
1091 | free_in_cluster = s->cluster_size - offset_into_cluster(s, offset); |
1092 | do { |
1093 | if (!offset || free_in_cluster < size) { |
1094 | int64_t new_cluster; |
1095 | |
1096 | new_cluster = alloc_clusters_noref(bs, s->cluster_size, |
1097 | MIN(s->cluster_offset_mask, |
1098 | QCOW_MAX_CLUSTER_OFFSET)); |
1099 | if (new_cluster < 0) { |
1100 | return new_cluster; |
1101 | } |
1102 | |
1103 | if (new_cluster == 0) { |
1104 | qcow2_signal_corruption(bs, true, -1, -1, "Preventing invalid " |
1105 | "allocation of compressed cluster " |
1106 | "at offset 0" ); |
1107 | return -EIO; |
1108 | } |
1109 | |
1110 | if (!offset || ROUND_UP(offset, s->cluster_size) != new_cluster) { |
1111 | offset = new_cluster; |
1112 | free_in_cluster = s->cluster_size; |
1113 | } else { |
1114 | free_in_cluster += s->cluster_size; |
1115 | } |
1116 | } |
1117 | |
1118 | assert(offset); |
1119 | ret = update_refcount(bs, offset, size, 1, false, QCOW2_DISCARD_NEVER); |
1120 | if (ret < 0) { |
1121 | offset = 0; |
1122 | } |
1123 | } while (ret == -EAGAIN); |
1124 | if (ret < 0) { |
1125 | return ret; |
1126 | } |
1127 | |
1128 | /* The cluster refcount was incremented; refcount blocks must be flushed |
1129 | * before the caller's L2 table updates. */ |
1130 | qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); |
1131 | |
1132 | s->free_byte_offset = offset + size; |
1133 | if (!offset_into_cluster(s, s->free_byte_offset)) { |
1134 | s->free_byte_offset = 0; |
1135 | } |
1136 | |
1137 | return offset; |
1138 | } |
1139 | |
1140 | void qcow2_free_clusters(BlockDriverState *bs, |
1141 | int64_t offset, int64_t size, |
1142 | enum qcow2_discard_type type) |
1143 | { |
1144 | int ret; |
1145 | |
1146 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE); |
1147 | ret = update_refcount(bs, offset, size, 1, true, type); |
1148 | if (ret < 0) { |
1149 | fprintf(stderr, "qcow2_free_clusters failed: %s\n" , strerror(-ret)); |
1150 | /* TODO Remember the clusters to free them later and avoid leaking */ |
1151 | } |
1152 | } |
1153 | |
1154 | /* |
1155 | * Free a cluster using its L2 entry (handles clusters of all types, e.g. |
1156 | * normal cluster, compressed cluster, etc.) |
1157 | */ |
1158 | void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry, |
1159 | int nb_clusters, enum qcow2_discard_type type) |
1160 | { |
1161 | BDRVQcow2State *s = bs->opaque; |
1162 | QCow2ClusterType ctype = qcow2_get_cluster_type(bs, l2_entry); |
1163 | |
1164 | if (has_data_file(bs)) { |
1165 | if (s->discard_passthrough[type] && |
1166 | (ctype == QCOW2_CLUSTER_NORMAL || |
1167 | ctype == QCOW2_CLUSTER_ZERO_ALLOC)) |
1168 | { |
1169 | bdrv_pdiscard(s->data_file, l2_entry & L2E_OFFSET_MASK, |
1170 | nb_clusters << s->cluster_bits); |
1171 | } |
1172 | return; |
1173 | } |
1174 | |
1175 | switch (ctype) { |
1176 | case QCOW2_CLUSTER_COMPRESSED: |
1177 | { |
1178 | int64_t offset = (l2_entry & s->cluster_offset_mask) |
1179 | & QCOW2_COMPRESSED_SECTOR_MASK; |
1180 | int size = QCOW2_COMPRESSED_SECTOR_SIZE * |
1181 | (((l2_entry >> s->csize_shift) & s->csize_mask) + 1); |
1182 | qcow2_free_clusters(bs, offset, size, type); |
1183 | } |
1184 | break; |
1185 | case QCOW2_CLUSTER_NORMAL: |
1186 | case QCOW2_CLUSTER_ZERO_ALLOC: |
1187 | if (offset_into_cluster(s, l2_entry & L2E_OFFSET_MASK)) { |
1188 | qcow2_signal_corruption(bs, false, -1, -1, |
1189 | "Cannot free unaligned cluster %#llx" , |
1190 | l2_entry & L2E_OFFSET_MASK); |
1191 | } else { |
1192 | qcow2_free_clusters(bs, l2_entry & L2E_OFFSET_MASK, |
1193 | nb_clusters << s->cluster_bits, type); |
1194 | } |
1195 | break; |
1196 | case QCOW2_CLUSTER_ZERO_PLAIN: |
1197 | case QCOW2_CLUSTER_UNALLOCATED: |
1198 | break; |
1199 | default: |
1200 | abort(); |
1201 | } |
1202 | } |
1203 | |
1204 | int coroutine_fn qcow2_write_caches(BlockDriverState *bs) |
1205 | { |
1206 | BDRVQcow2State *s = bs->opaque; |
1207 | int ret; |
1208 | |
1209 | ret = qcow2_cache_write(bs, s->l2_table_cache); |
1210 | if (ret < 0) { |
1211 | return ret; |
1212 | } |
1213 | |
1214 | if (qcow2_need_accurate_refcounts(s)) { |
1215 | ret = qcow2_cache_write(bs, s->refcount_block_cache); |
1216 | if (ret < 0) { |
1217 | return ret; |
1218 | } |
1219 | } |
1220 | |
1221 | return 0; |
1222 | } |
1223 | |
1224 | int coroutine_fn qcow2_flush_caches(BlockDriverState *bs) |
1225 | { |
1226 | int ret = qcow2_write_caches(bs); |
1227 | if (ret < 0) { |
1228 | return ret; |
1229 | } |
1230 | |
1231 | return bdrv_flush(bs->file->bs); |
1232 | } |
1233 | |
1234 | /*********************************************************/ |
1235 | /* snapshots and image creation */ |
1236 | |
1237 | |
1238 | |
1239 | /* update the refcounts of snapshots and the copied flag */ |
1240 | int qcow2_update_snapshot_refcount(BlockDriverState *bs, |
1241 | int64_t l1_table_offset, int l1_size, int addend) |
1242 | { |
1243 | BDRVQcow2State *s = bs->opaque; |
1244 | uint64_t *l1_table, *l2_slice, l2_offset, entry, l1_size2, refcount; |
1245 | bool l1_allocated = false; |
1246 | int64_t old_entry, old_l2_offset; |
1247 | unsigned slice, slice_size2, n_slices; |
1248 | int i, j, l1_modified = 0, nb_csectors; |
1249 | int ret; |
1250 | |
1251 | assert(addend >= -1 && addend <= 1); |
1252 | |
1253 | l2_slice = NULL; |
1254 | l1_table = NULL; |
1255 | l1_size2 = l1_size * sizeof(uint64_t); |
1256 | slice_size2 = s->l2_slice_size * sizeof(uint64_t); |
1257 | n_slices = s->cluster_size / slice_size2; |
1258 | |
1259 | s->cache_discards = true; |
1260 | |
1261 | /* WARNING: qcow2_snapshot_goto relies on this function not using the |
1262 | * l1_table_offset when it is the current s->l1_table_offset! Be careful |
1263 | * when changing this! */ |
1264 | if (l1_table_offset != s->l1_table_offset) { |
1265 | l1_table = g_try_malloc0(ROUND_UP(l1_size2, 512)); |
1266 | if (l1_size2 && l1_table == NULL) { |
1267 | ret = -ENOMEM; |
1268 | goto fail; |
1269 | } |
1270 | l1_allocated = true; |
1271 | |
1272 | ret = bdrv_pread(bs->file, l1_table_offset, l1_table, l1_size2); |
1273 | if (ret < 0) { |
1274 | goto fail; |
1275 | } |
1276 | |
1277 | for (i = 0; i < l1_size; i++) { |
1278 | be64_to_cpus(&l1_table[i]); |
1279 | } |
1280 | } else { |
1281 | assert(l1_size == s->l1_size); |
1282 | l1_table = s->l1_table; |
1283 | l1_allocated = false; |
1284 | } |
1285 | |
1286 | for (i = 0; i < l1_size; i++) { |
1287 | l2_offset = l1_table[i]; |
1288 | if (l2_offset) { |
1289 | old_l2_offset = l2_offset; |
1290 | l2_offset &= L1E_OFFSET_MASK; |
1291 | |
1292 | if (offset_into_cluster(s, l2_offset)) { |
1293 | qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" |
1294 | PRIx64 " unaligned (L1 index: %#x)" , |
1295 | l2_offset, i); |
1296 | ret = -EIO; |
1297 | goto fail; |
1298 | } |
1299 | |
1300 | for (slice = 0; slice < n_slices; slice++) { |
1301 | ret = qcow2_cache_get(bs, s->l2_table_cache, |
1302 | l2_offset + slice * slice_size2, |
1303 | (void **) &l2_slice); |
1304 | if (ret < 0) { |
1305 | goto fail; |
1306 | } |
1307 | |
1308 | for (j = 0; j < s->l2_slice_size; j++) { |
1309 | uint64_t cluster_index; |
1310 | uint64_t offset; |
1311 | |
1312 | entry = be64_to_cpu(l2_slice[j]); |
1313 | old_entry = entry; |
1314 | entry &= ~QCOW_OFLAG_COPIED; |
1315 | offset = entry & L2E_OFFSET_MASK; |
1316 | |
1317 | switch (qcow2_get_cluster_type(bs, entry)) { |
1318 | case QCOW2_CLUSTER_COMPRESSED: |
1319 | nb_csectors = ((entry >> s->csize_shift) & |
1320 | s->csize_mask) + 1; |
1321 | if (addend != 0) { |
1322 | uint64_t coffset = (entry & s->cluster_offset_mask) |
1323 | & QCOW2_COMPRESSED_SECTOR_MASK; |
1324 | ret = update_refcount( |
1325 | bs, coffset, |
1326 | nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE, |
1327 | abs(addend), addend < 0, |
1328 | QCOW2_DISCARD_SNAPSHOT); |
1329 | if (ret < 0) { |
1330 | goto fail; |
1331 | } |
1332 | } |
1333 | /* compressed clusters are never modified */ |
1334 | refcount = 2; |
1335 | break; |
1336 | |
1337 | case QCOW2_CLUSTER_NORMAL: |
1338 | case QCOW2_CLUSTER_ZERO_ALLOC: |
1339 | if (offset_into_cluster(s, offset)) { |
1340 | /* Here l2_index means table (not slice) index */ |
1341 | int l2_index = slice * s->l2_slice_size + j; |
1342 | qcow2_signal_corruption( |
1343 | bs, true, -1, -1, "Cluster " |
1344 | "allocation offset %#" PRIx64 |
1345 | " unaligned (L2 offset: %#" |
1346 | PRIx64 ", L2 index: %#x)" , |
1347 | offset, l2_offset, l2_index); |
1348 | ret = -EIO; |
1349 | goto fail; |
1350 | } |
1351 | |
1352 | cluster_index = offset >> s->cluster_bits; |
1353 | assert(cluster_index); |
1354 | if (addend != 0) { |
1355 | ret = qcow2_update_cluster_refcount( |
1356 | bs, cluster_index, abs(addend), addend < 0, |
1357 | QCOW2_DISCARD_SNAPSHOT); |
1358 | if (ret < 0) { |
1359 | goto fail; |
1360 | } |
1361 | } |
1362 | |
1363 | ret = qcow2_get_refcount(bs, cluster_index, &refcount); |
1364 | if (ret < 0) { |
1365 | goto fail; |
1366 | } |
1367 | break; |
1368 | |
1369 | case QCOW2_CLUSTER_ZERO_PLAIN: |
1370 | case QCOW2_CLUSTER_UNALLOCATED: |
1371 | refcount = 0; |
1372 | break; |
1373 | |
1374 | default: |
1375 | abort(); |
1376 | } |
1377 | |
1378 | if (refcount == 1) { |
1379 | entry |= QCOW_OFLAG_COPIED; |
1380 | } |
1381 | if (entry != old_entry) { |
1382 | if (addend > 0) { |
1383 | qcow2_cache_set_dependency(bs, s->l2_table_cache, |
1384 | s->refcount_block_cache); |
1385 | } |
1386 | l2_slice[j] = cpu_to_be64(entry); |
1387 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, |
1388 | l2_slice); |
1389 | } |
1390 | } |
1391 | |
1392 | qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice); |
1393 | } |
1394 | |
1395 | if (addend != 0) { |
1396 | ret = qcow2_update_cluster_refcount(bs, l2_offset >> |
1397 | s->cluster_bits, |
1398 | abs(addend), addend < 0, |
1399 | QCOW2_DISCARD_SNAPSHOT); |
1400 | if (ret < 0) { |
1401 | goto fail; |
1402 | } |
1403 | } |
1404 | ret = qcow2_get_refcount(bs, l2_offset >> s->cluster_bits, |
1405 | &refcount); |
1406 | if (ret < 0) { |
1407 | goto fail; |
1408 | } else if (refcount == 1) { |
1409 | l2_offset |= QCOW_OFLAG_COPIED; |
1410 | } |
1411 | if (l2_offset != old_l2_offset) { |
1412 | l1_table[i] = l2_offset; |
1413 | l1_modified = 1; |
1414 | } |
1415 | } |
1416 | } |
1417 | |
1418 | ret = bdrv_flush(bs); |
1419 | fail: |
1420 | if (l2_slice) { |
1421 | qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice); |
1422 | } |
1423 | |
1424 | s->cache_discards = false; |
1425 | qcow2_process_discards(bs, ret); |
1426 | |
1427 | /* Update L1 only if it isn't deleted anyway (addend = -1) */ |
1428 | if (ret == 0 && addend >= 0 && l1_modified) { |
1429 | for (i = 0; i < l1_size; i++) { |
1430 | cpu_to_be64s(&l1_table[i]); |
1431 | } |
1432 | |
1433 | ret = bdrv_pwrite_sync(bs->file, l1_table_offset, |
1434 | l1_table, l1_size2); |
1435 | |
1436 | for (i = 0; i < l1_size; i++) { |
1437 | be64_to_cpus(&l1_table[i]); |
1438 | } |
1439 | } |
1440 | if (l1_allocated) |
1441 | g_free(l1_table); |
1442 | return ret; |
1443 | } |
1444 | |
1445 | |
1446 | |
1447 | |
1448 | /*********************************************************/ |
1449 | /* refcount checking functions */ |
1450 | |
1451 | |
1452 | static uint64_t refcount_array_byte_size(BDRVQcow2State *s, uint64_t entries) |
1453 | { |
1454 | /* This assertion holds because there is no way we can address more than |
1455 | * 2^(64 - 9) clusters at once (with cluster size 512 = 2^9, and because |
1456 | * offsets have to be representable in bytes); due to every cluster |
1457 | * corresponding to one refcount entry, we are well below that limit */ |
1458 | assert(entries < (UINT64_C(1) << (64 - 9))); |
1459 | |
1460 | /* Thanks to the assertion this will not overflow, because |
1461 | * s->refcount_order < 7. |
1462 | * (note: x << s->refcount_order == x * s->refcount_bits) */ |
1463 | return DIV_ROUND_UP(entries << s->refcount_order, 8); |
1464 | } |
1465 | |
1466 | /** |
1467 | * Reallocates *array so that it can hold new_size entries. *size must contain |
1468 | * the current number of entries in *array. If the reallocation fails, *array |
1469 | * and *size will not be modified and -errno will be returned. If the |
1470 | * reallocation is successful, *array will be set to the new buffer, *size |
1471 | * will be set to new_size and 0 will be returned. The size of the reallocated |
1472 | * refcount array buffer will be aligned to a cluster boundary, and the newly |
1473 | * allocated area will be zeroed. |
1474 | */ |
1475 | static int realloc_refcount_array(BDRVQcow2State *s, void **array, |
1476 | int64_t *size, int64_t new_size) |
1477 | { |
1478 | int64_t old_byte_size, new_byte_size; |
1479 | void *new_ptr; |
1480 | |
1481 | /* Round to clusters so the array can be directly written to disk */ |
1482 | old_byte_size = size_to_clusters(s, refcount_array_byte_size(s, *size)) |
1483 | * s->cluster_size; |
1484 | new_byte_size = size_to_clusters(s, refcount_array_byte_size(s, new_size)) |
1485 | * s->cluster_size; |
1486 | |
1487 | if (new_byte_size == old_byte_size) { |
1488 | *size = new_size; |
1489 | return 0; |
1490 | } |
1491 | |
1492 | assert(new_byte_size > 0); |
1493 | |
1494 | if (new_byte_size > SIZE_MAX) { |
1495 | return -ENOMEM; |
1496 | } |
1497 | |
1498 | new_ptr = g_try_realloc(*array, new_byte_size); |
1499 | if (!new_ptr) { |
1500 | return -ENOMEM; |
1501 | } |
1502 | |
1503 | if (new_byte_size > old_byte_size) { |
1504 | memset((char *)new_ptr + old_byte_size, 0, |
1505 | new_byte_size - old_byte_size); |
1506 | } |
1507 | |
1508 | *array = new_ptr; |
1509 | *size = new_size; |
1510 | |
1511 | return 0; |
1512 | } |
1513 | |
1514 | /* |
1515 | * Increases the refcount for a range of clusters in a given refcount table. |
1516 | * This is used to construct a temporary refcount table out of L1 and L2 tables |
1517 | * which can be compared to the refcount table saved in the image. |
1518 | * |
1519 | * Modifies the number of errors in res. |
1520 | */ |
1521 | int qcow2_inc_refcounts_imrt(BlockDriverState *bs, BdrvCheckResult *res, |
1522 | void **refcount_table, |
1523 | int64_t *refcount_table_size, |
1524 | int64_t offset, int64_t size) |
1525 | { |
1526 | BDRVQcow2State *s = bs->opaque; |
1527 | uint64_t start, last, cluster_offset, k, refcount; |
1528 | int64_t file_len; |
1529 | int ret; |
1530 | |
1531 | if (size <= 0) { |
1532 | return 0; |
1533 | } |
1534 | |
1535 | file_len = bdrv_getlength(bs->file->bs); |
1536 | if (file_len < 0) { |
1537 | return file_len; |
1538 | } |
1539 | |
1540 | /* |
1541 | * Last cluster of qcow2 image may be semi-allocated, so it may be OK to |
1542 | * reference some space after file end but it should be less than one |
1543 | * cluster. |
1544 | */ |
1545 | if (offset + size - file_len >= s->cluster_size) { |
1546 | fprintf(stderr, "ERROR: counting reference for region exceeding the " |
1547 | "end of the file by one cluster or more: offset 0x%" PRIx64 |
1548 | " size 0x%" PRIx64 "\n" , offset, size); |
1549 | res->corruptions++; |
1550 | return 0; |
1551 | } |
1552 | |
1553 | start = start_of_cluster(s, offset); |
1554 | last = start_of_cluster(s, offset + size - 1); |
1555 | for(cluster_offset = start; cluster_offset <= last; |
1556 | cluster_offset += s->cluster_size) { |
1557 | k = cluster_offset >> s->cluster_bits; |
1558 | if (k >= *refcount_table_size) { |
1559 | ret = realloc_refcount_array(s, refcount_table, |
1560 | refcount_table_size, k + 1); |
1561 | if (ret < 0) { |
1562 | res->check_errors++; |
1563 | return ret; |
1564 | } |
1565 | } |
1566 | |
1567 | refcount = s->get_refcount(*refcount_table, k); |
1568 | if (refcount == s->refcount_max) { |
1569 | fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 |
1570 | "\n" , cluster_offset); |
1571 | fprintf(stderr, "Use qemu-img amend to increase the refcount entry " |
1572 | "width or qemu-img convert to create a clean copy if the " |
1573 | "image cannot be opened for writing\n" ); |
1574 | res->corruptions++; |
1575 | continue; |
1576 | } |
1577 | s->set_refcount(*refcount_table, k, refcount + 1); |
1578 | } |
1579 | |
1580 | return 0; |
1581 | } |
1582 | |
1583 | /* Flags for check_refcounts_l1() and check_refcounts_l2() */ |
1584 | enum { |
1585 | CHECK_FRAG_INFO = 0x2, /* update BlockFragInfo counters */ |
1586 | }; |
1587 | |
1588 | /* |
1589 | * Increases the refcount in the given refcount table for the all clusters |
1590 | * referenced in the L2 table. While doing so, performs some checks on L2 |
1591 | * entries. |
1592 | * |
1593 | * Returns the number of errors found by the checks or -errno if an internal |
1594 | * error occurred. |
1595 | */ |
1596 | static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, |
1597 | void **refcount_table, |
1598 | int64_t *refcount_table_size, int64_t l2_offset, |
1599 | int flags, BdrvCheckMode fix, bool active) |
1600 | { |
1601 | BDRVQcow2State *s = bs->opaque; |
1602 | uint64_t *l2_table, l2_entry; |
1603 | uint64_t next_contiguous_offset = 0; |
1604 | int i, l2_size, nb_csectors, ret; |
1605 | |
1606 | /* Read L2 table from disk */ |
1607 | l2_size = s->l2_size * sizeof(uint64_t); |
1608 | l2_table = g_malloc(l2_size); |
1609 | |
1610 | ret = bdrv_pread(bs->file, l2_offset, l2_table, l2_size); |
1611 | if (ret < 0) { |
1612 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n" ); |
1613 | res->check_errors++; |
1614 | goto fail; |
1615 | } |
1616 | |
1617 | /* Do the actual checks */ |
1618 | for(i = 0; i < s->l2_size; i++) { |
1619 | l2_entry = be64_to_cpu(l2_table[i]); |
1620 | |
1621 | switch (qcow2_get_cluster_type(bs, l2_entry)) { |
1622 | case QCOW2_CLUSTER_COMPRESSED: |
1623 | /* Compressed clusters don't have QCOW_OFLAG_COPIED */ |
1624 | if (l2_entry & QCOW_OFLAG_COPIED) { |
1625 | fprintf(stderr, "ERROR: coffset=0x%" PRIx64 ": " |
1626 | "copied flag must never be set for compressed " |
1627 | "clusters\n" , l2_entry & s->cluster_offset_mask); |
1628 | l2_entry &= ~QCOW_OFLAG_COPIED; |
1629 | res->corruptions++; |
1630 | } |
1631 | |
1632 | if (has_data_file(bs)) { |
1633 | fprintf(stderr, "ERROR compressed cluster %d with data file, " |
1634 | "entry=0x%" PRIx64 "\n" , i, l2_entry); |
1635 | res->corruptions++; |
1636 | break; |
1637 | } |
1638 | |
1639 | /* Mark cluster as used */ |
1640 | nb_csectors = ((l2_entry >> s->csize_shift) & |
1641 | s->csize_mask) + 1; |
1642 | l2_entry &= s->cluster_offset_mask; |
1643 | ret = qcow2_inc_refcounts_imrt( |
1644 | bs, res, refcount_table, refcount_table_size, |
1645 | l2_entry & QCOW2_COMPRESSED_SECTOR_MASK, |
1646 | nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE); |
1647 | if (ret < 0) { |
1648 | goto fail; |
1649 | } |
1650 | |
1651 | if (flags & CHECK_FRAG_INFO) { |
1652 | res->bfi.allocated_clusters++; |
1653 | res->bfi.compressed_clusters++; |
1654 | |
1655 | /* Compressed clusters are fragmented by nature. Since they |
1656 | * take up sub-sector space but we only have sector granularity |
1657 | * I/O we need to re-read the same sectors even for adjacent |
1658 | * compressed clusters. |
1659 | */ |
1660 | res->bfi.fragmented_clusters++; |
1661 | } |
1662 | break; |
1663 | |
1664 | case QCOW2_CLUSTER_ZERO_ALLOC: |
1665 | case QCOW2_CLUSTER_NORMAL: |
1666 | { |
1667 | uint64_t offset = l2_entry & L2E_OFFSET_MASK; |
1668 | |
1669 | /* Correct offsets are cluster aligned */ |
1670 | if (offset_into_cluster(s, offset)) { |
1671 | res->corruptions++; |
1672 | |
1673 | if (qcow2_get_cluster_type(bs, l2_entry) == |
1674 | QCOW2_CLUSTER_ZERO_ALLOC) |
1675 | { |
1676 | fprintf(stderr, "%s offset=%" PRIx64 ": Preallocated zero " |
1677 | "cluster is not properly aligned; L2 entry " |
1678 | "corrupted.\n" , |
1679 | fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR" , |
1680 | offset); |
1681 | if (fix & BDRV_FIX_ERRORS) { |
1682 | uint64_t l2e_offset = |
1683 | l2_offset + (uint64_t)i * sizeof(uint64_t); |
1684 | int ign = active ? QCOW2_OL_ACTIVE_L2 : |
1685 | QCOW2_OL_INACTIVE_L2; |
1686 | |
1687 | l2_entry = QCOW_OFLAG_ZERO; |
1688 | l2_table[i] = cpu_to_be64(l2_entry); |
1689 | ret = qcow2_pre_write_overlap_check(bs, ign, |
1690 | l2e_offset, sizeof(uint64_t), false); |
1691 | if (ret < 0) { |
1692 | fprintf(stderr, "ERROR: Overlap check failed\n" ); |
1693 | res->check_errors++; |
1694 | /* Something is seriously wrong, so abort checking |
1695 | * this L2 table */ |
1696 | goto fail; |
1697 | } |
1698 | |
1699 | ret = bdrv_pwrite_sync(bs->file, l2e_offset, |
1700 | &l2_table[i], sizeof(uint64_t)); |
1701 | if (ret < 0) { |
1702 | fprintf(stderr, "ERROR: Failed to overwrite L2 " |
1703 | "table entry: %s\n" , strerror(-ret)); |
1704 | res->check_errors++; |
1705 | /* Do not abort, continue checking the rest of this |
1706 | * L2 table's entries */ |
1707 | } else { |
1708 | res->corruptions--; |
1709 | res->corruptions_fixed++; |
1710 | /* Skip marking the cluster as used |
1711 | * (it is unused now) */ |
1712 | continue; |
1713 | } |
1714 | } |
1715 | } else { |
1716 | fprintf(stderr, "ERROR offset=%" PRIx64 ": Data cluster is " |
1717 | "not properly aligned; L2 entry corrupted.\n" , offset); |
1718 | } |
1719 | } |
1720 | |
1721 | if (flags & CHECK_FRAG_INFO) { |
1722 | res->bfi.allocated_clusters++; |
1723 | if (next_contiguous_offset && |
1724 | offset != next_contiguous_offset) { |
1725 | res->bfi.fragmented_clusters++; |
1726 | } |
1727 | next_contiguous_offset = offset + s->cluster_size; |
1728 | } |
1729 | |
1730 | /* Mark cluster as used */ |
1731 | if (!has_data_file(bs)) { |
1732 | ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, |
1733 | refcount_table_size, |
1734 | offset, s->cluster_size); |
1735 | if (ret < 0) { |
1736 | goto fail; |
1737 | } |
1738 | } |
1739 | break; |
1740 | } |
1741 | |
1742 | case QCOW2_CLUSTER_ZERO_PLAIN: |
1743 | case QCOW2_CLUSTER_UNALLOCATED: |
1744 | break; |
1745 | |
1746 | default: |
1747 | abort(); |
1748 | } |
1749 | } |
1750 | |
1751 | g_free(l2_table); |
1752 | return 0; |
1753 | |
1754 | fail: |
1755 | g_free(l2_table); |
1756 | return ret; |
1757 | } |
1758 | |
1759 | /* |
1760 | * Increases the refcount for the L1 table, its L2 tables and all referenced |
1761 | * clusters in the given refcount table. While doing so, performs some checks |
1762 | * on L1 and L2 entries. |
1763 | * |
1764 | * Returns the number of errors found by the checks or -errno if an internal |
1765 | * error occurred. |
1766 | */ |
1767 | static int check_refcounts_l1(BlockDriverState *bs, |
1768 | BdrvCheckResult *res, |
1769 | void **refcount_table, |
1770 | int64_t *refcount_table_size, |
1771 | int64_t l1_table_offset, int l1_size, |
1772 | int flags, BdrvCheckMode fix, bool active) |
1773 | { |
1774 | BDRVQcow2State *s = bs->opaque; |
1775 | uint64_t *l1_table = NULL, l2_offset, l1_size2; |
1776 | int i, ret; |
1777 | |
1778 | l1_size2 = l1_size * sizeof(uint64_t); |
1779 | |
1780 | /* Mark L1 table as used */ |
1781 | ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, refcount_table_size, |
1782 | l1_table_offset, l1_size2); |
1783 | if (ret < 0) { |
1784 | goto fail; |
1785 | } |
1786 | |
1787 | /* Read L1 table entries from disk */ |
1788 | if (l1_size2 > 0) { |
1789 | l1_table = g_try_malloc(l1_size2); |
1790 | if (l1_table == NULL) { |
1791 | ret = -ENOMEM; |
1792 | res->check_errors++; |
1793 | goto fail; |
1794 | } |
1795 | ret = bdrv_pread(bs->file, l1_table_offset, l1_table, l1_size2); |
1796 | if (ret < 0) { |
1797 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n" ); |
1798 | res->check_errors++; |
1799 | goto fail; |
1800 | } |
1801 | for(i = 0;i < l1_size; i++) |
1802 | be64_to_cpus(&l1_table[i]); |
1803 | } |
1804 | |
1805 | /* Do the actual checks */ |
1806 | for(i = 0; i < l1_size; i++) { |
1807 | l2_offset = l1_table[i]; |
1808 | if (l2_offset) { |
1809 | /* Mark L2 table as used */ |
1810 | l2_offset &= L1E_OFFSET_MASK; |
1811 | ret = qcow2_inc_refcounts_imrt(bs, res, |
1812 | refcount_table, refcount_table_size, |
1813 | l2_offset, s->cluster_size); |
1814 | if (ret < 0) { |
1815 | goto fail; |
1816 | } |
1817 | |
1818 | /* L2 tables are cluster aligned */ |
1819 | if (offset_into_cluster(s, l2_offset)) { |
1820 | fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " |
1821 | "cluster aligned; L1 entry corrupted\n" , l2_offset); |
1822 | res->corruptions++; |
1823 | } |
1824 | |
1825 | /* Process and check L2 entries */ |
1826 | ret = check_refcounts_l2(bs, res, refcount_table, |
1827 | refcount_table_size, l2_offset, flags, |
1828 | fix, active); |
1829 | if (ret < 0) { |
1830 | goto fail; |
1831 | } |
1832 | } |
1833 | } |
1834 | g_free(l1_table); |
1835 | return 0; |
1836 | |
1837 | fail: |
1838 | g_free(l1_table); |
1839 | return ret; |
1840 | } |
1841 | |
1842 | /* |
1843 | * Checks the OFLAG_COPIED flag for all L1 and L2 entries. |
1844 | * |
1845 | * This function does not print an error message nor does it increment |
1846 | * check_errors if qcow2_get_refcount fails (this is because such an error will |
1847 | * have been already detected and sufficiently signaled by the calling function |
1848 | * (qcow2_check_refcounts) by the time this function is called). |
1849 | */ |
1850 | static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res, |
1851 | BdrvCheckMode fix) |
1852 | { |
1853 | BDRVQcow2State *s = bs->opaque; |
1854 | uint64_t *l2_table = qemu_blockalign(bs, s->cluster_size); |
1855 | int ret; |
1856 | uint64_t refcount; |
1857 | int i, j; |
1858 | bool repair; |
1859 | |
1860 | if (fix & BDRV_FIX_ERRORS) { |
1861 | /* Always repair */ |
1862 | repair = true; |
1863 | } else if (fix & BDRV_FIX_LEAKS) { |
1864 | /* Repair only if that seems safe: This function is always |
1865 | * called after the refcounts have been fixed, so the refcount |
1866 | * is accurate if that repair was successful */ |
1867 | repair = !res->check_errors && !res->corruptions && !res->leaks; |
1868 | } else { |
1869 | repair = false; |
1870 | } |
1871 | |
1872 | for (i = 0; i < s->l1_size; i++) { |
1873 | uint64_t l1_entry = s->l1_table[i]; |
1874 | uint64_t l2_offset = l1_entry & L1E_OFFSET_MASK; |
1875 | int l2_dirty = 0; |
1876 | |
1877 | if (!l2_offset) { |
1878 | continue; |
1879 | } |
1880 | |
1881 | ret = qcow2_get_refcount(bs, l2_offset >> s->cluster_bits, |
1882 | &refcount); |
1883 | if (ret < 0) { |
1884 | /* don't print message nor increment check_errors */ |
1885 | continue; |
1886 | } |
1887 | if ((refcount == 1) != ((l1_entry & QCOW_OFLAG_COPIED) != 0)) { |
1888 | res->corruptions++; |
1889 | fprintf(stderr, "%s OFLAG_COPIED L2 cluster: l1_index=%d " |
1890 | "l1_entry=%" PRIx64 " refcount=%" PRIu64 "\n" , |
1891 | repair ? "Repairing" : "ERROR" , i, l1_entry, refcount); |
1892 | if (repair) { |
1893 | s->l1_table[i] = refcount == 1 |
1894 | ? l1_entry | QCOW_OFLAG_COPIED |
1895 | : l1_entry & ~QCOW_OFLAG_COPIED; |
1896 | ret = qcow2_write_l1_entry(bs, i); |
1897 | if (ret < 0) { |
1898 | res->check_errors++; |
1899 | goto fail; |
1900 | } |
1901 | res->corruptions--; |
1902 | res->corruptions_fixed++; |
1903 | } |
1904 | } |
1905 | |
1906 | ret = bdrv_pread(bs->file, l2_offset, l2_table, |
1907 | s->l2_size * sizeof(uint64_t)); |
1908 | if (ret < 0) { |
1909 | fprintf(stderr, "ERROR: Could not read L2 table: %s\n" , |
1910 | strerror(-ret)); |
1911 | res->check_errors++; |
1912 | goto fail; |
1913 | } |
1914 | |
1915 | for (j = 0; j < s->l2_size; j++) { |
1916 | uint64_t l2_entry = be64_to_cpu(l2_table[j]); |
1917 | uint64_t data_offset = l2_entry & L2E_OFFSET_MASK; |
1918 | QCow2ClusterType cluster_type = qcow2_get_cluster_type(bs, l2_entry); |
1919 | |
1920 | if (cluster_type == QCOW2_CLUSTER_NORMAL || |
1921 | cluster_type == QCOW2_CLUSTER_ZERO_ALLOC) { |
1922 | if (has_data_file(bs)) { |
1923 | refcount = 1; |
1924 | } else { |
1925 | ret = qcow2_get_refcount(bs, |
1926 | data_offset >> s->cluster_bits, |
1927 | &refcount); |
1928 | if (ret < 0) { |
1929 | /* don't print message nor increment check_errors */ |
1930 | continue; |
1931 | } |
1932 | } |
1933 | if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) { |
1934 | res->corruptions++; |
1935 | fprintf(stderr, "%s OFLAG_COPIED data cluster: " |
1936 | "l2_entry=%" PRIx64 " refcount=%" PRIu64 "\n" , |
1937 | repair ? "Repairing" : "ERROR" , l2_entry, refcount); |
1938 | if (repair) { |
1939 | l2_table[j] = cpu_to_be64(refcount == 1 |
1940 | ? l2_entry | QCOW_OFLAG_COPIED |
1941 | : l2_entry & ~QCOW_OFLAG_COPIED); |
1942 | l2_dirty++; |
1943 | } |
1944 | } |
1945 | } |
1946 | } |
1947 | |
1948 | if (l2_dirty > 0) { |
1949 | ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L2, |
1950 | l2_offset, s->cluster_size, |
1951 | false); |
1952 | if (ret < 0) { |
1953 | fprintf(stderr, "ERROR: Could not write L2 table; metadata " |
1954 | "overlap check failed: %s\n" , strerror(-ret)); |
1955 | res->check_errors++; |
1956 | goto fail; |
1957 | } |
1958 | |
1959 | ret = bdrv_pwrite(bs->file, l2_offset, l2_table, |
1960 | s->cluster_size); |
1961 | if (ret < 0) { |
1962 | fprintf(stderr, "ERROR: Could not write L2 table: %s\n" , |
1963 | strerror(-ret)); |
1964 | res->check_errors++; |
1965 | goto fail; |
1966 | } |
1967 | res->corruptions -= l2_dirty; |
1968 | res->corruptions_fixed += l2_dirty; |
1969 | } |
1970 | } |
1971 | |
1972 | ret = 0; |
1973 | |
1974 | fail: |
1975 | qemu_vfree(l2_table); |
1976 | return ret; |
1977 | } |
1978 | |
1979 | /* |
1980 | * Checks consistency of refblocks and accounts for each refblock in |
1981 | * *refcount_table. |
1982 | */ |
1983 | static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res, |
1984 | BdrvCheckMode fix, bool *rebuild, |
1985 | void **refcount_table, int64_t *nb_clusters) |
1986 | { |
1987 | BDRVQcow2State *s = bs->opaque; |
1988 | int64_t i, size; |
1989 | int ret; |
1990 | |
1991 | for(i = 0; i < s->refcount_table_size; i++) { |
1992 | uint64_t offset, cluster; |
1993 | offset = s->refcount_table[i]; |
1994 | cluster = offset >> s->cluster_bits; |
1995 | |
1996 | /* Refcount blocks are cluster aligned */ |
1997 | if (offset_into_cluster(s, offset)) { |
1998 | fprintf(stderr, "ERROR refcount block %" PRId64 " is not " |
1999 | "cluster aligned; refcount table entry corrupted\n" , i); |
2000 | res->corruptions++; |
2001 | *rebuild = true; |
2002 | continue; |
2003 | } |
2004 | |
2005 | if (cluster >= *nb_clusters) { |
2006 | res->corruptions++; |
2007 | fprintf(stderr, "%s refcount block %" PRId64 " is outside image\n" , |
2008 | fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR" , i); |
2009 | |
2010 | if (fix & BDRV_FIX_ERRORS) { |
2011 | int64_t new_nb_clusters; |
2012 | Error *local_err = NULL; |
2013 | |
2014 | if (offset > INT64_MAX - s->cluster_size) { |
2015 | ret = -EINVAL; |
2016 | goto resize_fail; |
2017 | } |
2018 | |
2019 | ret = bdrv_truncate(bs->file, offset + s->cluster_size, |
2020 | PREALLOC_MODE_OFF, &local_err); |
2021 | if (ret < 0) { |
2022 | error_report_err(local_err); |
2023 | goto resize_fail; |
2024 | } |
2025 | size = bdrv_getlength(bs->file->bs); |
2026 | if (size < 0) { |
2027 | ret = size; |
2028 | goto resize_fail; |
2029 | } |
2030 | |
2031 | new_nb_clusters = size_to_clusters(s, size); |
2032 | assert(new_nb_clusters >= *nb_clusters); |
2033 | |
2034 | ret = realloc_refcount_array(s, refcount_table, |
2035 | nb_clusters, new_nb_clusters); |
2036 | if (ret < 0) { |
2037 | res->check_errors++; |
2038 | return ret; |
2039 | } |
2040 | |
2041 | if (cluster >= *nb_clusters) { |
2042 | ret = -EINVAL; |
2043 | goto resize_fail; |
2044 | } |
2045 | |
2046 | res->corruptions--; |
2047 | res->corruptions_fixed++; |
2048 | ret = qcow2_inc_refcounts_imrt(bs, res, |
2049 | refcount_table, nb_clusters, |
2050 | offset, s->cluster_size); |
2051 | if (ret < 0) { |
2052 | return ret; |
2053 | } |
2054 | /* No need to check whether the refcount is now greater than 1: |
2055 | * This area was just allocated and zeroed, so it can only be |
2056 | * exactly 1 after qcow2_inc_refcounts_imrt() */ |
2057 | continue; |
2058 | |
2059 | resize_fail: |
2060 | *rebuild = true; |
2061 | fprintf(stderr, "ERROR could not resize image: %s\n" , |
2062 | strerror(-ret)); |
2063 | } |
2064 | continue; |
2065 | } |
2066 | |
2067 | if (offset != 0) { |
2068 | ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, nb_clusters, |
2069 | offset, s->cluster_size); |
2070 | if (ret < 0) { |
2071 | return ret; |
2072 | } |
2073 | if (s->get_refcount(*refcount_table, cluster) != 1) { |
2074 | fprintf(stderr, "ERROR refcount block %" PRId64 |
2075 | " refcount=%" PRIu64 "\n" , i, |
2076 | s->get_refcount(*refcount_table, cluster)); |
2077 | res->corruptions++; |
2078 | *rebuild = true; |
2079 | } |
2080 | } |
2081 | } |
2082 | |
2083 | return 0; |
2084 | } |
2085 | |
2086 | /* |
2087 | * Calculates an in-memory refcount table. |
2088 | */ |
2089 | static int calculate_refcounts(BlockDriverState *bs, BdrvCheckResult *res, |
2090 | BdrvCheckMode fix, bool *rebuild, |
2091 | void **refcount_table, int64_t *nb_clusters) |
2092 | { |
2093 | BDRVQcow2State *s = bs->opaque; |
2094 | int64_t i; |
2095 | QCowSnapshot *sn; |
2096 | int ret; |
2097 | |
2098 | if (!*refcount_table) { |
2099 | int64_t old_size = 0; |
2100 | ret = realloc_refcount_array(s, refcount_table, |
2101 | &old_size, *nb_clusters); |
2102 | if (ret < 0) { |
2103 | res->check_errors++; |
2104 | return ret; |
2105 | } |
2106 | } |
2107 | |
2108 | /* header */ |
2109 | ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, nb_clusters, |
2110 | 0, s->cluster_size); |
2111 | if (ret < 0) { |
2112 | return ret; |
2113 | } |
2114 | |
2115 | /* current L1 table */ |
2116 | ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
2117 | s->l1_table_offset, s->l1_size, CHECK_FRAG_INFO, |
2118 | fix, true); |
2119 | if (ret < 0) { |
2120 | return ret; |
2121 | } |
2122 | |
2123 | /* snapshots */ |
2124 | if (has_data_file(bs) && s->nb_snapshots) { |
2125 | fprintf(stderr, "ERROR %d snapshots in image with data file\n" , |
2126 | s->nb_snapshots); |
2127 | res->corruptions++; |
2128 | } |
2129 | |
2130 | for (i = 0; i < s->nb_snapshots; i++) { |
2131 | sn = s->snapshots + i; |
2132 | if (offset_into_cluster(s, sn->l1_table_offset)) { |
2133 | fprintf(stderr, "ERROR snapshot %s (%s) l1_offset=%#" PRIx64 ": " |
2134 | "L1 table is not cluster aligned; snapshot table entry " |
2135 | "corrupted\n" , sn->id_str, sn->name, sn->l1_table_offset); |
2136 | res->corruptions++; |
2137 | continue; |
2138 | } |
2139 | if (sn->l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { |
2140 | fprintf(stderr, "ERROR snapshot %s (%s) l1_size=%#" PRIx32 ": " |
2141 | "L1 table is too large; snapshot table entry corrupted\n" , |
2142 | sn->id_str, sn->name, sn->l1_size); |
2143 | res->corruptions++; |
2144 | continue; |
2145 | } |
2146 | ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
2147 | sn->l1_table_offset, sn->l1_size, 0, fix, |
2148 | false); |
2149 | if (ret < 0) { |
2150 | return ret; |
2151 | } |
2152 | } |
2153 | ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, nb_clusters, |
2154 | s->snapshots_offset, s->snapshots_size); |
2155 | if (ret < 0) { |
2156 | return ret; |
2157 | } |
2158 | |
2159 | /* refcount data */ |
2160 | ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, nb_clusters, |
2161 | s->refcount_table_offset, |
2162 | s->refcount_table_size * sizeof(uint64_t)); |
2163 | if (ret < 0) { |
2164 | return ret; |
2165 | } |
2166 | |
2167 | /* encryption */ |
2168 | if (s->crypto_header.length) { |
2169 | ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, nb_clusters, |
2170 | s->crypto_header.offset, |
2171 | s->crypto_header.length); |
2172 | if (ret < 0) { |
2173 | return ret; |
2174 | } |
2175 | } |
2176 | |
2177 | /* bitmaps */ |
2178 | ret = qcow2_check_bitmaps_refcounts(bs, res, refcount_table, nb_clusters); |
2179 | if (ret < 0) { |
2180 | return ret; |
2181 | } |
2182 | |
2183 | return check_refblocks(bs, res, fix, rebuild, refcount_table, nb_clusters); |
2184 | } |
2185 | |
2186 | /* |
2187 | * Compares the actual reference count for each cluster in the image against the |
2188 | * refcount as reported by the refcount structures on-disk. |
2189 | */ |
2190 | static void compare_refcounts(BlockDriverState *bs, BdrvCheckResult *res, |
2191 | BdrvCheckMode fix, bool *rebuild, |
2192 | int64_t *highest_cluster, |
2193 | void *refcount_table, int64_t nb_clusters) |
2194 | { |
2195 | BDRVQcow2State *s = bs->opaque; |
2196 | int64_t i; |
2197 | uint64_t refcount1, refcount2; |
2198 | int ret; |
2199 | |
2200 | for (i = 0, *highest_cluster = 0; i < nb_clusters; i++) { |
2201 | ret = qcow2_get_refcount(bs, i, &refcount1); |
2202 | if (ret < 0) { |
2203 | fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n" , |
2204 | i, strerror(-ret)); |
2205 | res->check_errors++; |
2206 | continue; |
2207 | } |
2208 | |
2209 | refcount2 = s->get_refcount(refcount_table, i); |
2210 | |
2211 | if (refcount1 > 0 || refcount2 > 0) { |
2212 | *highest_cluster = i; |
2213 | } |
2214 | |
2215 | if (refcount1 != refcount2) { |
2216 | /* Check if we're allowed to fix the mismatch */ |
2217 | int *num_fixed = NULL; |
2218 | if (refcount1 == 0) { |
2219 | *rebuild = true; |
2220 | } else if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) { |
2221 | num_fixed = &res->leaks_fixed; |
2222 | } else if (refcount1 < refcount2 && (fix & BDRV_FIX_ERRORS)) { |
2223 | num_fixed = &res->corruptions_fixed; |
2224 | } |
2225 | |
2226 | fprintf(stderr, "%s cluster %" PRId64 " refcount=%" PRIu64 |
2227 | " reference=%" PRIu64 "\n" , |
2228 | num_fixed != NULL ? "Repairing" : |
2229 | refcount1 < refcount2 ? "ERROR" : |
2230 | "Leaked" , |
2231 | i, refcount1, refcount2); |
2232 | |
2233 | if (num_fixed) { |
2234 | ret = update_refcount(bs, i << s->cluster_bits, 1, |
2235 | refcount_diff(refcount1, refcount2), |
2236 | refcount1 > refcount2, |
2237 | QCOW2_DISCARD_ALWAYS); |
2238 | if (ret >= 0) { |
2239 | (*num_fixed)++; |
2240 | continue; |
2241 | } |
2242 | } |
2243 | |
2244 | /* And if we couldn't, print an error */ |
2245 | if (refcount1 < refcount2) { |
2246 | res->corruptions++; |
2247 | } else { |
2248 | res->leaks++; |
2249 | } |
2250 | } |
2251 | } |
2252 | } |
2253 | |
2254 | /* |
2255 | * Allocates clusters using an in-memory refcount table (IMRT) in contrast to |
2256 | * the on-disk refcount structures. |
2257 | * |
2258 | * On input, *first_free_cluster tells where to start looking, and need not |
2259 | * actually be a free cluster; the returned offset will not be before that |
2260 | * cluster. On output, *first_free_cluster points to the first gap found, even |
2261 | * if that gap was too small to be used as the returned offset. |
2262 | * |
2263 | * Note that *first_free_cluster is a cluster index whereas the return value is |
2264 | * an offset. |
2265 | */ |
2266 | static int64_t alloc_clusters_imrt(BlockDriverState *bs, |
2267 | int cluster_count, |
2268 | void **refcount_table, |
2269 | int64_t *imrt_nb_clusters, |
2270 | int64_t *first_free_cluster) |
2271 | { |
2272 | BDRVQcow2State *s = bs->opaque; |
2273 | int64_t cluster = *first_free_cluster, i; |
2274 | bool first_gap = true; |
2275 | int contiguous_free_clusters; |
2276 | int ret; |
2277 | |
2278 | /* Starting at *first_free_cluster, find a range of at least cluster_count |
2279 | * continuously free clusters */ |
2280 | for (contiguous_free_clusters = 0; |
2281 | cluster < *imrt_nb_clusters && |
2282 | contiguous_free_clusters < cluster_count; |
2283 | cluster++) |
2284 | { |
2285 | if (!s->get_refcount(*refcount_table, cluster)) { |
2286 | contiguous_free_clusters++; |
2287 | if (first_gap) { |
2288 | /* If this is the first free cluster found, update |
2289 | * *first_free_cluster accordingly */ |
2290 | *first_free_cluster = cluster; |
2291 | first_gap = false; |
2292 | } |
2293 | } else if (contiguous_free_clusters) { |
2294 | contiguous_free_clusters = 0; |
2295 | } |
2296 | } |
2297 | |
2298 | /* If contiguous_free_clusters is greater than zero, it contains the number |
2299 | * of continuously free clusters until the current cluster; the first free |
2300 | * cluster in the current "gap" is therefore |
2301 | * cluster - contiguous_free_clusters */ |
2302 | |
2303 | /* If no such range could be found, grow the in-memory refcount table |
2304 | * accordingly to append free clusters at the end of the image */ |
2305 | if (contiguous_free_clusters < cluster_count) { |
2306 | /* contiguous_free_clusters clusters are already empty at the image end; |
2307 | * we need cluster_count clusters; therefore, we have to allocate |
2308 | * cluster_count - contiguous_free_clusters new clusters at the end of |
2309 | * the image (which is the current value of cluster; note that cluster |
2310 | * may exceed old_imrt_nb_clusters if *first_free_cluster pointed beyond |
2311 | * the image end) */ |
2312 | ret = realloc_refcount_array(s, refcount_table, imrt_nb_clusters, |
2313 | cluster + cluster_count |
2314 | - contiguous_free_clusters); |
2315 | if (ret < 0) { |
2316 | return ret; |
2317 | } |
2318 | } |
2319 | |
2320 | /* Go back to the first free cluster */ |
2321 | cluster -= contiguous_free_clusters; |
2322 | for (i = 0; i < cluster_count; i++) { |
2323 | s->set_refcount(*refcount_table, cluster + i, 1); |
2324 | } |
2325 | |
2326 | return cluster << s->cluster_bits; |
2327 | } |
2328 | |
2329 | /* |
2330 | * Creates a new refcount structure based solely on the in-memory information |
2331 | * given through *refcount_table. All necessary allocations will be reflected |
2332 | * in that array. |
2333 | * |
2334 | * On success, the old refcount structure is leaked (it will be covered by the |
2335 | * new refcount structure). |
2336 | */ |
2337 | static int rebuild_refcount_structure(BlockDriverState *bs, |
2338 | BdrvCheckResult *res, |
2339 | void **refcount_table, |
2340 | int64_t *nb_clusters) |
2341 | { |
2342 | BDRVQcow2State *s = bs->opaque; |
2343 | int64_t first_free_cluster = 0, reftable_offset = -1, cluster = 0; |
2344 | int64_t refblock_offset, refblock_start, refblock_index; |
2345 | uint32_t reftable_size = 0; |
2346 | uint64_t *on_disk_reftable = NULL; |
2347 | void *on_disk_refblock; |
2348 | int ret = 0; |
2349 | struct { |
2350 | uint64_t reftable_offset; |
2351 | uint32_t reftable_clusters; |
2352 | } QEMU_PACKED reftable_offset_and_clusters; |
2353 | |
2354 | qcow2_cache_empty(bs, s->refcount_block_cache); |
2355 | |
2356 | write_refblocks: |
2357 | for (; cluster < *nb_clusters; cluster++) { |
2358 | if (!s->get_refcount(*refcount_table, cluster)) { |
2359 | continue; |
2360 | } |
2361 | |
2362 | refblock_index = cluster >> s->refcount_block_bits; |
2363 | refblock_start = refblock_index << s->refcount_block_bits; |
2364 | |
2365 | /* Don't allocate a cluster in a refblock already written to disk */ |
2366 | if (first_free_cluster < refblock_start) { |
2367 | first_free_cluster = refblock_start; |
2368 | } |
2369 | refblock_offset = alloc_clusters_imrt(bs, 1, refcount_table, |
2370 | nb_clusters, &first_free_cluster); |
2371 | if (refblock_offset < 0) { |
2372 | fprintf(stderr, "ERROR allocating refblock: %s\n" , |
2373 | strerror(-refblock_offset)); |
2374 | res->check_errors++; |
2375 | ret = refblock_offset; |
2376 | goto fail; |
2377 | } |
2378 | |
2379 | if (reftable_size <= refblock_index) { |
2380 | uint32_t old_reftable_size = reftable_size; |
2381 | uint64_t *new_on_disk_reftable; |
2382 | |
2383 | reftable_size = ROUND_UP((refblock_index + 1) * sizeof(uint64_t), |
2384 | s->cluster_size) / sizeof(uint64_t); |
2385 | new_on_disk_reftable = g_try_realloc(on_disk_reftable, |
2386 | reftable_size * |
2387 | sizeof(uint64_t)); |
2388 | if (!new_on_disk_reftable) { |
2389 | res->check_errors++; |
2390 | ret = -ENOMEM; |
2391 | goto fail; |
2392 | } |
2393 | on_disk_reftable = new_on_disk_reftable; |
2394 | |
2395 | memset(on_disk_reftable + old_reftable_size, 0, |
2396 | (reftable_size - old_reftable_size) * sizeof(uint64_t)); |
2397 | |
2398 | /* The offset we have for the reftable is now no longer valid; |
2399 | * this will leak that range, but we can easily fix that by running |
2400 | * a leak-fixing check after this rebuild operation */ |
2401 | reftable_offset = -1; |
2402 | } else { |
2403 | assert(on_disk_reftable); |
2404 | } |
2405 | on_disk_reftable[refblock_index] = refblock_offset; |
2406 | |
2407 | /* If this is apparently the last refblock (for now), try to squeeze the |
2408 | * reftable in */ |
2409 | if (refblock_index == (*nb_clusters - 1) >> s->refcount_block_bits && |
2410 | reftable_offset < 0) |
2411 | { |
2412 | uint64_t reftable_clusters = size_to_clusters(s, reftable_size * |
2413 | sizeof(uint64_t)); |
2414 | reftable_offset = alloc_clusters_imrt(bs, reftable_clusters, |
2415 | refcount_table, nb_clusters, |
2416 | &first_free_cluster); |
2417 | if (reftable_offset < 0) { |
2418 | fprintf(stderr, "ERROR allocating reftable: %s\n" , |
2419 | strerror(-reftable_offset)); |
2420 | res->check_errors++; |
2421 | ret = reftable_offset; |
2422 | goto fail; |
2423 | } |
2424 | } |
2425 | |
2426 | ret = qcow2_pre_write_overlap_check(bs, 0, refblock_offset, |
2427 | s->cluster_size, false); |
2428 | if (ret < 0) { |
2429 | fprintf(stderr, "ERROR writing refblock: %s\n" , strerror(-ret)); |
2430 | goto fail; |
2431 | } |
2432 | |
2433 | /* The size of *refcount_table is always cluster-aligned, therefore the |
2434 | * write operation will not overflow */ |
2435 | on_disk_refblock = (void *)((char *) *refcount_table + |
2436 | refblock_index * s->cluster_size); |
2437 | |
2438 | ret = bdrv_pwrite(bs->file, refblock_offset, on_disk_refblock, |
2439 | s->cluster_size); |
2440 | if (ret < 0) { |
2441 | fprintf(stderr, "ERROR writing refblock: %s\n" , strerror(-ret)); |
2442 | goto fail; |
2443 | } |
2444 | |
2445 | /* Go to the end of this refblock */ |
2446 | cluster = refblock_start + s->refcount_block_size - 1; |
2447 | } |
2448 | |
2449 | if (reftable_offset < 0) { |
2450 | uint64_t post_refblock_start, reftable_clusters; |
2451 | |
2452 | post_refblock_start = ROUND_UP(*nb_clusters, s->refcount_block_size); |
2453 | reftable_clusters = size_to_clusters(s, |
2454 | reftable_size * sizeof(uint64_t)); |
2455 | /* Not pretty but simple */ |
2456 | if (first_free_cluster < post_refblock_start) { |
2457 | first_free_cluster = post_refblock_start; |
2458 | } |
2459 | reftable_offset = alloc_clusters_imrt(bs, reftable_clusters, |
2460 | refcount_table, nb_clusters, |
2461 | &first_free_cluster); |
2462 | if (reftable_offset < 0) { |
2463 | fprintf(stderr, "ERROR allocating reftable: %s\n" , |
2464 | strerror(-reftable_offset)); |
2465 | res->check_errors++; |
2466 | ret = reftable_offset; |
2467 | goto fail; |
2468 | } |
2469 | |
2470 | goto write_refblocks; |
2471 | } |
2472 | |
2473 | for (refblock_index = 0; refblock_index < reftable_size; refblock_index++) { |
2474 | cpu_to_be64s(&on_disk_reftable[refblock_index]); |
2475 | } |
2476 | |
2477 | ret = qcow2_pre_write_overlap_check(bs, 0, reftable_offset, |
2478 | reftable_size * sizeof(uint64_t), |
2479 | false); |
2480 | if (ret < 0) { |
2481 | fprintf(stderr, "ERROR writing reftable: %s\n" , strerror(-ret)); |
2482 | goto fail; |
2483 | } |
2484 | |
2485 | assert(reftable_size < INT_MAX / sizeof(uint64_t)); |
2486 | ret = bdrv_pwrite(bs->file, reftable_offset, on_disk_reftable, |
2487 | reftable_size * sizeof(uint64_t)); |
2488 | if (ret < 0) { |
2489 | fprintf(stderr, "ERROR writing reftable: %s\n" , strerror(-ret)); |
2490 | goto fail; |
2491 | } |
2492 | |
2493 | /* Enter new reftable into the image header */ |
2494 | reftable_offset_and_clusters.reftable_offset = cpu_to_be64(reftable_offset); |
2495 | reftable_offset_and_clusters.reftable_clusters = |
2496 | cpu_to_be32(size_to_clusters(s, reftable_size * sizeof(uint64_t))); |
2497 | ret = bdrv_pwrite_sync(bs->file, |
2498 | offsetof(QCowHeader, refcount_table_offset), |
2499 | &reftable_offset_and_clusters, |
2500 | sizeof(reftable_offset_and_clusters)); |
2501 | if (ret < 0) { |
2502 | fprintf(stderr, "ERROR setting reftable: %s\n" , strerror(-ret)); |
2503 | goto fail; |
2504 | } |
2505 | |
2506 | for (refblock_index = 0; refblock_index < reftable_size; refblock_index++) { |
2507 | be64_to_cpus(&on_disk_reftable[refblock_index]); |
2508 | } |
2509 | s->refcount_table = on_disk_reftable; |
2510 | s->refcount_table_offset = reftable_offset; |
2511 | s->refcount_table_size = reftable_size; |
2512 | update_max_refcount_table_index(s); |
2513 | |
2514 | return 0; |
2515 | |
2516 | fail: |
2517 | g_free(on_disk_reftable); |
2518 | return ret; |
2519 | } |
2520 | |
2521 | /* |
2522 | * Checks an image for refcount consistency. |
2523 | * |
2524 | * Returns 0 if no errors are found, the number of errors in case the image is |
2525 | * detected as corrupted, and -errno when an internal error occurred. |
2526 | */ |
2527 | int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, |
2528 | BdrvCheckMode fix) |
2529 | { |
2530 | BDRVQcow2State *s = bs->opaque; |
2531 | BdrvCheckResult pre_compare_res; |
2532 | int64_t size, highest_cluster, nb_clusters; |
2533 | void *refcount_table = NULL; |
2534 | bool rebuild = false; |
2535 | int ret; |
2536 | |
2537 | size = bdrv_getlength(bs->file->bs); |
2538 | if (size < 0) { |
2539 | res->check_errors++; |
2540 | return size; |
2541 | } |
2542 | |
2543 | nb_clusters = size_to_clusters(s, size); |
2544 | if (nb_clusters > INT_MAX) { |
2545 | res->check_errors++; |
2546 | return -EFBIG; |
2547 | } |
2548 | |
2549 | res->bfi.total_clusters = |
2550 | size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE); |
2551 | |
2552 | ret = calculate_refcounts(bs, res, fix, &rebuild, &refcount_table, |
2553 | &nb_clusters); |
2554 | if (ret < 0) { |
2555 | goto fail; |
2556 | } |
2557 | |
2558 | /* In case we don't need to rebuild the refcount structure (but want to fix |
2559 | * something), this function is immediately called again, in which case the |
2560 | * result should be ignored */ |
2561 | pre_compare_res = *res; |
2562 | compare_refcounts(bs, res, 0, &rebuild, &highest_cluster, refcount_table, |
2563 | nb_clusters); |
2564 | |
2565 | if (rebuild && (fix & BDRV_FIX_ERRORS)) { |
2566 | BdrvCheckResult old_res = *res; |
2567 | int fresh_leaks = 0; |
2568 | |
2569 | fprintf(stderr, "Rebuilding refcount structure\n" ); |
2570 | ret = rebuild_refcount_structure(bs, res, &refcount_table, |
2571 | &nb_clusters); |
2572 | if (ret < 0) { |
2573 | goto fail; |
2574 | } |
2575 | |
2576 | res->corruptions = 0; |
2577 | res->leaks = 0; |
2578 | |
2579 | /* Because the old reftable has been exchanged for a new one the |
2580 | * references have to be recalculated */ |
2581 | rebuild = false; |
2582 | memset(refcount_table, 0, refcount_array_byte_size(s, nb_clusters)); |
2583 | ret = calculate_refcounts(bs, res, 0, &rebuild, &refcount_table, |
2584 | &nb_clusters); |
2585 | if (ret < 0) { |
2586 | goto fail; |
2587 | } |
2588 | |
2589 | if (fix & BDRV_FIX_LEAKS) { |
2590 | /* The old refcount structures are now leaked, fix it; the result |
2591 | * can be ignored, aside from leaks which were introduced by |
2592 | * rebuild_refcount_structure() that could not be fixed */ |
2593 | BdrvCheckResult saved_res = *res; |
2594 | *res = (BdrvCheckResult){ 0 }; |
2595 | |
2596 | compare_refcounts(bs, res, BDRV_FIX_LEAKS, &rebuild, |
2597 | &highest_cluster, refcount_table, nb_clusters); |
2598 | if (rebuild) { |
2599 | fprintf(stderr, "ERROR rebuilt refcount structure is still " |
2600 | "broken\n" ); |
2601 | } |
2602 | |
2603 | /* Any leaks accounted for here were introduced by |
2604 | * rebuild_refcount_structure() because that function has created a |
2605 | * new refcount structure from scratch */ |
2606 | fresh_leaks = res->leaks; |
2607 | *res = saved_res; |
2608 | } |
2609 | |
2610 | if (res->corruptions < old_res.corruptions) { |
2611 | res->corruptions_fixed += old_res.corruptions - res->corruptions; |
2612 | } |
2613 | if (res->leaks < old_res.leaks) { |
2614 | res->leaks_fixed += old_res.leaks - res->leaks; |
2615 | } |
2616 | res->leaks += fresh_leaks; |
2617 | } else if (fix) { |
2618 | if (rebuild) { |
2619 | fprintf(stderr, "ERROR need to rebuild refcount structures\n" ); |
2620 | res->check_errors++; |
2621 | ret = -EIO; |
2622 | goto fail; |
2623 | } |
2624 | |
2625 | if (res->leaks || res->corruptions) { |
2626 | *res = pre_compare_res; |
2627 | compare_refcounts(bs, res, fix, &rebuild, &highest_cluster, |
2628 | refcount_table, nb_clusters); |
2629 | } |
2630 | } |
2631 | |
2632 | /* check OFLAG_COPIED */ |
2633 | ret = check_oflag_copied(bs, res, fix); |
2634 | if (ret < 0) { |
2635 | goto fail; |
2636 | } |
2637 | |
2638 | res->image_end_offset = (highest_cluster + 1) * s->cluster_size; |
2639 | ret = 0; |
2640 | |
2641 | fail: |
2642 | g_free(refcount_table); |
2643 | |
2644 | return ret; |
2645 | } |
2646 | |
2647 | #define overlaps_with(ofs, sz) \ |
2648 | ranges_overlap(offset, size, ofs, sz) |
2649 | |
2650 | /* |
2651 | * Checks if the given offset into the image file is actually free to use by |
2652 | * looking for overlaps with important metadata sections (L1/L2 tables etc.), |
2653 | * i.e. a sanity check without relying on the refcount tables. |
2654 | * |
2655 | * The ign parameter specifies what checks not to perform (being a bitmask of |
2656 | * QCow2MetadataOverlap values), i.e., what sections to ignore. |
2657 | * |
2658 | * Returns: |
2659 | * - 0 if writing to this offset will not affect the mentioned metadata |
2660 | * - a positive QCow2MetadataOverlap value indicating one overlapping section |
2661 | * - a negative value (-errno) indicating an error while performing a check, |
2662 | * e.g. when bdrv_read failed on QCOW2_OL_INACTIVE_L2 |
2663 | */ |
2664 | int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset, |
2665 | int64_t size) |
2666 | { |
2667 | BDRVQcow2State *s = bs->opaque; |
2668 | int chk = s->overlap_check & ~ign; |
2669 | int i, j; |
2670 | |
2671 | if (!size) { |
2672 | return 0; |
2673 | } |
2674 | |
2675 | if (chk & QCOW2_OL_MAIN_HEADER) { |
2676 | if (offset < s->cluster_size) { |
2677 | return QCOW2_OL_MAIN_HEADER; |
2678 | } |
2679 | } |
2680 | |
2681 | /* align range to test to cluster boundaries */ |
2682 | size = ROUND_UP(offset_into_cluster(s, offset) + size, s->cluster_size); |
2683 | offset = start_of_cluster(s, offset); |
2684 | |
2685 | if ((chk & QCOW2_OL_ACTIVE_L1) && s->l1_size) { |
2686 | if (overlaps_with(s->l1_table_offset, s->l1_size * sizeof(uint64_t))) { |
2687 | return QCOW2_OL_ACTIVE_L1; |
2688 | } |
2689 | } |
2690 | |
2691 | if ((chk & QCOW2_OL_REFCOUNT_TABLE) && s->refcount_table_size) { |
2692 | if (overlaps_with(s->refcount_table_offset, |
2693 | s->refcount_table_size * sizeof(uint64_t))) { |
2694 | return QCOW2_OL_REFCOUNT_TABLE; |
2695 | } |
2696 | } |
2697 | |
2698 | if ((chk & QCOW2_OL_SNAPSHOT_TABLE) && s->snapshots_size) { |
2699 | if (overlaps_with(s->snapshots_offset, s->snapshots_size)) { |
2700 | return QCOW2_OL_SNAPSHOT_TABLE; |
2701 | } |
2702 | } |
2703 | |
2704 | if ((chk & QCOW2_OL_INACTIVE_L1) && s->snapshots) { |
2705 | for (i = 0; i < s->nb_snapshots; i++) { |
2706 | if (s->snapshots[i].l1_size && |
2707 | overlaps_with(s->snapshots[i].l1_table_offset, |
2708 | s->snapshots[i].l1_size * sizeof(uint64_t))) { |
2709 | return QCOW2_OL_INACTIVE_L1; |
2710 | } |
2711 | } |
2712 | } |
2713 | |
2714 | if ((chk & QCOW2_OL_ACTIVE_L2) && s->l1_table) { |
2715 | for (i = 0; i < s->l1_size; i++) { |
2716 | if ((s->l1_table[i] & L1E_OFFSET_MASK) && |
2717 | overlaps_with(s->l1_table[i] & L1E_OFFSET_MASK, |
2718 | s->cluster_size)) { |
2719 | return QCOW2_OL_ACTIVE_L2; |
2720 | } |
2721 | } |
2722 | } |
2723 | |
2724 | if ((chk & QCOW2_OL_REFCOUNT_BLOCK) && s->refcount_table) { |
2725 | unsigned last_entry = s->max_refcount_table_index; |
2726 | assert(last_entry < s->refcount_table_size); |
2727 | assert(last_entry + 1 == s->refcount_table_size || |
2728 | (s->refcount_table[last_entry + 1] & REFT_OFFSET_MASK) == 0); |
2729 | for (i = 0; i <= last_entry; i++) { |
2730 | if ((s->refcount_table[i] & REFT_OFFSET_MASK) && |
2731 | overlaps_with(s->refcount_table[i] & REFT_OFFSET_MASK, |
2732 | s->cluster_size)) { |
2733 | return QCOW2_OL_REFCOUNT_BLOCK; |
2734 | } |
2735 | } |
2736 | } |
2737 | |
2738 | if ((chk & QCOW2_OL_INACTIVE_L2) && s->snapshots) { |
2739 | for (i = 0; i < s->nb_snapshots; i++) { |
2740 | uint64_t l1_ofs = s->snapshots[i].l1_table_offset; |
2741 | uint32_t l1_sz = s->snapshots[i].l1_size; |
2742 | uint64_t l1_sz2 = l1_sz * sizeof(uint64_t); |
2743 | uint64_t *l1; |
2744 | int ret; |
2745 | |
2746 | ret = qcow2_validate_table(bs, l1_ofs, l1_sz, sizeof(uint64_t), |
2747 | QCOW_MAX_L1_SIZE, "" , NULL); |
2748 | if (ret < 0) { |
2749 | return ret; |
2750 | } |
2751 | |
2752 | l1 = g_try_malloc(l1_sz2); |
2753 | |
2754 | if (l1_sz2 && l1 == NULL) { |
2755 | return -ENOMEM; |
2756 | } |
2757 | |
2758 | ret = bdrv_pread(bs->file, l1_ofs, l1, l1_sz2); |
2759 | if (ret < 0) { |
2760 | g_free(l1); |
2761 | return ret; |
2762 | } |
2763 | |
2764 | for (j = 0; j < l1_sz; j++) { |
2765 | uint64_t l2_ofs = be64_to_cpu(l1[j]) & L1E_OFFSET_MASK; |
2766 | if (l2_ofs && overlaps_with(l2_ofs, s->cluster_size)) { |
2767 | g_free(l1); |
2768 | return QCOW2_OL_INACTIVE_L2; |
2769 | } |
2770 | } |
2771 | |
2772 | g_free(l1); |
2773 | } |
2774 | } |
2775 | |
2776 | if ((chk & QCOW2_OL_BITMAP_DIRECTORY) && |
2777 | (s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) |
2778 | { |
2779 | if (overlaps_with(s->bitmap_directory_offset, |
2780 | s->bitmap_directory_size)) |
2781 | { |
2782 | return QCOW2_OL_BITMAP_DIRECTORY; |
2783 | } |
2784 | } |
2785 | |
2786 | return 0; |
2787 | } |
2788 | |
2789 | static const char *metadata_ol_names[] = { |
2790 | [QCOW2_OL_MAIN_HEADER_BITNR] = "qcow2_header" , |
2791 | [QCOW2_OL_ACTIVE_L1_BITNR] = "active L1 table" , |
2792 | [QCOW2_OL_ACTIVE_L2_BITNR] = "active L2 table" , |
2793 | [QCOW2_OL_REFCOUNT_TABLE_BITNR] = "refcount table" , |
2794 | [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = "refcount block" , |
2795 | [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = "snapshot table" , |
2796 | [QCOW2_OL_INACTIVE_L1_BITNR] = "inactive L1 table" , |
2797 | [QCOW2_OL_INACTIVE_L2_BITNR] = "inactive L2 table" , |
2798 | [QCOW2_OL_BITMAP_DIRECTORY_BITNR] = "bitmap directory" , |
2799 | }; |
2800 | QEMU_BUILD_BUG_ON(QCOW2_OL_MAX_BITNR != ARRAY_SIZE(metadata_ol_names)); |
2801 | |
2802 | /* |
2803 | * First performs a check for metadata overlaps (through |
2804 | * qcow2_check_metadata_overlap); if that fails with a negative value (error |
2805 | * while performing a check), that value is returned. If an impending overlap |
2806 | * is detected, the BDS will be made unusable, the qcow2 file marked corrupt |
2807 | * and -EIO returned. |
2808 | * |
2809 | * Returns 0 if there were neither overlaps nor errors while checking for |
2810 | * overlaps; or a negative value (-errno) on error. |
2811 | */ |
2812 | int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset, |
2813 | int64_t size, bool data_file) |
2814 | { |
2815 | int ret; |
2816 | |
2817 | if (data_file && has_data_file(bs)) { |
2818 | return 0; |
2819 | } |
2820 | |
2821 | ret = qcow2_check_metadata_overlap(bs, ign, offset, size); |
2822 | if (ret < 0) { |
2823 | return ret; |
2824 | } else if (ret > 0) { |
2825 | int metadata_ol_bitnr = ctz32(ret); |
2826 | assert(metadata_ol_bitnr < QCOW2_OL_MAX_BITNR); |
2827 | |
2828 | qcow2_signal_corruption(bs, true, offset, size, "Preventing invalid " |
2829 | "write on metadata (overlaps with %s)" , |
2830 | metadata_ol_names[metadata_ol_bitnr]); |
2831 | return -EIO; |
2832 | } |
2833 | |
2834 | return 0; |
2835 | } |
2836 | |
2837 | /* A pointer to a function of this type is given to walk_over_reftable(). That |
2838 | * function will create refblocks and pass them to a RefblockFinishOp once they |
2839 | * are completed (@refblock). @refblock_empty is set if the refblock is |
2840 | * completely empty. |
2841 | * |
2842 | * Along with the refblock, a corresponding reftable entry is passed, in the |
2843 | * reftable @reftable (which may be reallocated) at @reftable_index. |
2844 | * |
2845 | * @allocated should be set to true if a new cluster has been allocated. |
2846 | */ |
2847 | typedef int (RefblockFinishOp)(BlockDriverState *bs, uint64_t **reftable, |
2848 | uint64_t reftable_index, uint64_t *reftable_size, |
2849 | void *refblock, bool refblock_empty, |
2850 | bool *allocated, Error **errp); |
2851 | |
2852 | /** |
2853 | * This "operation" for walk_over_reftable() allocates the refblock on disk (if |
2854 | * it is not empty) and inserts its offset into the new reftable. The size of |
2855 | * this new reftable is increased as required. |
2856 | */ |
2857 | static int alloc_refblock(BlockDriverState *bs, uint64_t **reftable, |
2858 | uint64_t reftable_index, uint64_t *reftable_size, |
2859 | void *refblock, bool refblock_empty, bool *allocated, |
2860 | Error **errp) |
2861 | { |
2862 | BDRVQcow2State *s = bs->opaque; |
2863 | int64_t offset; |
2864 | |
2865 | if (!refblock_empty && reftable_index >= *reftable_size) { |
2866 | uint64_t *new_reftable; |
2867 | uint64_t new_reftable_size; |
2868 | |
2869 | new_reftable_size = ROUND_UP(reftable_index + 1, |
2870 | s->cluster_size / sizeof(uint64_t)); |
2871 | if (new_reftable_size > QCOW_MAX_REFTABLE_SIZE / sizeof(uint64_t)) { |
2872 | error_setg(errp, |
2873 | "This operation would make the refcount table grow " |
2874 | "beyond the maximum size supported by QEMU, aborting" ); |
2875 | return -ENOTSUP; |
2876 | } |
2877 | |
2878 | new_reftable = g_try_realloc(*reftable, new_reftable_size * |
2879 | sizeof(uint64_t)); |
2880 | if (!new_reftable) { |
2881 | error_setg(errp, "Failed to increase reftable buffer size" ); |
2882 | return -ENOMEM; |
2883 | } |
2884 | |
2885 | memset(new_reftable + *reftable_size, 0, |
2886 | (new_reftable_size - *reftable_size) * sizeof(uint64_t)); |
2887 | |
2888 | *reftable = new_reftable; |
2889 | *reftable_size = new_reftable_size; |
2890 | } |
2891 | |
2892 | if (!refblock_empty && !(*reftable)[reftable_index]) { |
2893 | offset = qcow2_alloc_clusters(bs, s->cluster_size); |
2894 | if (offset < 0) { |
2895 | error_setg_errno(errp, -offset, "Failed to allocate refblock" ); |
2896 | return offset; |
2897 | } |
2898 | (*reftable)[reftable_index] = offset; |
2899 | *allocated = true; |
2900 | } |
2901 | |
2902 | return 0; |
2903 | } |
2904 | |
2905 | /** |
2906 | * This "operation" for walk_over_reftable() writes the refblock to disk at the |
2907 | * offset specified by the new reftable's entry. It does not modify the new |
2908 | * reftable or change any refcounts. |
2909 | */ |
2910 | static int flush_refblock(BlockDriverState *bs, uint64_t **reftable, |
2911 | uint64_t reftable_index, uint64_t *reftable_size, |
2912 | void *refblock, bool refblock_empty, bool *allocated, |
2913 | Error **errp) |
2914 | { |
2915 | BDRVQcow2State *s = bs->opaque; |
2916 | int64_t offset; |
2917 | int ret; |
2918 | |
2919 | if (reftable_index < *reftable_size && (*reftable)[reftable_index]) { |
2920 | offset = (*reftable)[reftable_index]; |
2921 | |
2922 | ret = qcow2_pre_write_overlap_check(bs, 0, offset, s->cluster_size, |
2923 | false); |
2924 | if (ret < 0) { |
2925 | error_setg_errno(errp, -ret, "Overlap check failed" ); |
2926 | return ret; |
2927 | } |
2928 | |
2929 | ret = bdrv_pwrite(bs->file, offset, refblock, s->cluster_size); |
2930 | if (ret < 0) { |
2931 | error_setg_errno(errp, -ret, "Failed to write refblock" ); |
2932 | return ret; |
2933 | } |
2934 | } else { |
2935 | assert(refblock_empty); |
2936 | } |
2937 | |
2938 | return 0; |
2939 | } |
2940 | |
2941 | /** |
2942 | * This function walks over the existing reftable and every referenced refblock; |
2943 | * if @new_set_refcount is non-NULL, it is called for every refcount entry to |
2944 | * create an equal new entry in the passed @new_refblock. Once that |
2945 | * @new_refblock is completely filled, @operation will be called. |
2946 | * |
2947 | * @status_cb and @cb_opaque are used for the amend operation's status callback. |
2948 | * @index is the index of the walk_over_reftable() calls and @total is the total |
2949 | * number of walk_over_reftable() calls per amend operation. Both are used for |
2950 | * calculating the parameters for the status callback. |
2951 | * |
2952 | * @allocated is set to true if a new cluster has been allocated. |
2953 | */ |
2954 | static int walk_over_reftable(BlockDriverState *bs, uint64_t **new_reftable, |
2955 | uint64_t *new_reftable_index, |
2956 | uint64_t *new_reftable_size, |
2957 | void *new_refblock, int new_refblock_size, |
2958 | int new_refcount_bits, |
2959 | RefblockFinishOp *operation, bool *allocated, |
2960 | Qcow2SetRefcountFunc *new_set_refcount, |
2961 | BlockDriverAmendStatusCB *status_cb, |
2962 | void *cb_opaque, int index, int total, |
2963 | Error **errp) |
2964 | { |
2965 | BDRVQcow2State *s = bs->opaque; |
2966 | uint64_t reftable_index; |
2967 | bool new_refblock_empty = true; |
2968 | int refblock_index; |
2969 | int new_refblock_index = 0; |
2970 | int ret; |
2971 | |
2972 | for (reftable_index = 0; reftable_index < s->refcount_table_size; |
2973 | reftable_index++) |
2974 | { |
2975 | uint64_t refblock_offset = s->refcount_table[reftable_index] |
2976 | & REFT_OFFSET_MASK; |
2977 | |
2978 | status_cb(bs, (uint64_t)index * s->refcount_table_size + reftable_index, |
2979 | (uint64_t)total * s->refcount_table_size, cb_opaque); |
2980 | |
2981 | if (refblock_offset) { |
2982 | void *refblock; |
2983 | |
2984 | if (offset_into_cluster(s, refblock_offset)) { |
2985 | qcow2_signal_corruption(bs, true, -1, -1, "Refblock offset %#" |
2986 | PRIx64 " unaligned (reftable index: %#" |
2987 | PRIx64 ")" , refblock_offset, |
2988 | reftable_index); |
2989 | error_setg(errp, |
2990 | "Image is corrupt (unaligned refblock offset)" ); |
2991 | return -EIO; |
2992 | } |
2993 | |
2994 | ret = qcow2_cache_get(bs, s->refcount_block_cache, refblock_offset, |
2995 | &refblock); |
2996 | if (ret < 0) { |
2997 | error_setg_errno(errp, -ret, "Failed to retrieve refblock" ); |
2998 | return ret; |
2999 | } |
3000 | |
3001 | for (refblock_index = 0; refblock_index < s->refcount_block_size; |
3002 | refblock_index++) |
3003 | { |
3004 | uint64_t refcount; |
3005 | |
3006 | if (new_refblock_index >= new_refblock_size) { |
3007 | /* new_refblock is now complete */ |
3008 | ret = operation(bs, new_reftable, *new_reftable_index, |
3009 | new_reftable_size, new_refblock, |
3010 | new_refblock_empty, allocated, errp); |
3011 | if (ret < 0) { |
3012 | qcow2_cache_put(s->refcount_block_cache, &refblock); |
3013 | return ret; |
3014 | } |
3015 | |
3016 | (*new_reftable_index)++; |
3017 | new_refblock_index = 0; |
3018 | new_refblock_empty = true; |
3019 | } |
3020 | |
3021 | refcount = s->get_refcount(refblock, refblock_index); |
3022 | if (new_refcount_bits < 64 && refcount >> new_refcount_bits) { |
3023 | uint64_t offset; |
3024 | |
3025 | qcow2_cache_put(s->refcount_block_cache, &refblock); |
3026 | |
3027 | offset = ((reftable_index << s->refcount_block_bits) |
3028 | + refblock_index) << s->cluster_bits; |
3029 | |
3030 | error_setg(errp, "Cannot decrease refcount entry width to " |
3031 | "%i bits: Cluster at offset %#" PRIx64 " has a " |
3032 | "refcount of %" PRIu64, new_refcount_bits, |
3033 | offset, refcount); |
3034 | return -EINVAL; |
3035 | } |
3036 | |
3037 | if (new_set_refcount) { |
3038 | new_set_refcount(new_refblock, new_refblock_index++, |
3039 | refcount); |
3040 | } else { |
3041 | new_refblock_index++; |
3042 | } |
3043 | new_refblock_empty = new_refblock_empty && refcount == 0; |
3044 | } |
3045 | |
3046 | qcow2_cache_put(s->refcount_block_cache, &refblock); |
3047 | } else { |
3048 | /* No refblock means every refcount is 0 */ |
3049 | for (refblock_index = 0; refblock_index < s->refcount_block_size; |
3050 | refblock_index++) |
3051 | { |
3052 | if (new_refblock_index >= new_refblock_size) { |
3053 | /* new_refblock is now complete */ |
3054 | ret = operation(bs, new_reftable, *new_reftable_index, |
3055 | new_reftable_size, new_refblock, |
3056 | new_refblock_empty, allocated, errp); |
3057 | if (ret < 0) { |
3058 | return ret; |
3059 | } |
3060 | |
3061 | (*new_reftable_index)++; |
3062 | new_refblock_index = 0; |
3063 | new_refblock_empty = true; |
3064 | } |
3065 | |
3066 | if (new_set_refcount) { |
3067 | new_set_refcount(new_refblock, new_refblock_index++, 0); |
3068 | } else { |
3069 | new_refblock_index++; |
3070 | } |
3071 | } |
3072 | } |
3073 | } |
3074 | |
3075 | if (new_refblock_index > 0) { |
3076 | /* Complete the potentially existing partially filled final refblock */ |
3077 | if (new_set_refcount) { |
3078 | for (; new_refblock_index < new_refblock_size; |
3079 | new_refblock_index++) |
3080 | { |
3081 | new_set_refcount(new_refblock, new_refblock_index, 0); |
3082 | } |
3083 | } |
3084 | |
3085 | ret = operation(bs, new_reftable, *new_reftable_index, |
3086 | new_reftable_size, new_refblock, new_refblock_empty, |
3087 | allocated, errp); |
3088 | if (ret < 0) { |
3089 | return ret; |
3090 | } |
3091 | |
3092 | (*new_reftable_index)++; |
3093 | } |
3094 | |
3095 | status_cb(bs, (uint64_t)(index + 1) * s->refcount_table_size, |
3096 | (uint64_t)total * s->refcount_table_size, cb_opaque); |
3097 | |
3098 | return 0; |
3099 | } |
3100 | |
3101 | int qcow2_change_refcount_order(BlockDriverState *bs, int refcount_order, |
3102 | BlockDriverAmendStatusCB *status_cb, |
3103 | void *cb_opaque, Error **errp) |
3104 | { |
3105 | BDRVQcow2State *s = bs->opaque; |
3106 | Qcow2GetRefcountFunc *new_get_refcount; |
3107 | Qcow2SetRefcountFunc *new_set_refcount; |
3108 | void *new_refblock = qemu_blockalign(bs->file->bs, s->cluster_size); |
3109 | uint64_t *new_reftable = NULL, new_reftable_size = 0; |
3110 | uint64_t *old_reftable, old_reftable_size, old_reftable_offset; |
3111 | uint64_t new_reftable_index = 0; |
3112 | uint64_t i; |
3113 | int64_t new_reftable_offset = 0, allocated_reftable_size = 0; |
3114 | int new_refblock_size, new_refcount_bits = 1 << refcount_order; |
3115 | int old_refcount_order; |
3116 | int walk_index = 0; |
3117 | int ret; |
3118 | bool new_allocation; |
3119 | |
3120 | assert(s->qcow_version >= 3); |
3121 | assert(refcount_order >= 0 && refcount_order <= 6); |
3122 | |
3123 | /* see qcow2_open() */ |
3124 | new_refblock_size = 1 << (s->cluster_bits - (refcount_order - 3)); |
3125 | |
3126 | new_get_refcount = get_refcount_funcs[refcount_order]; |
3127 | new_set_refcount = set_refcount_funcs[refcount_order]; |
3128 | |
3129 | |
3130 | do { |
3131 | int total_walks; |
3132 | |
3133 | new_allocation = false; |
3134 | |
3135 | /* At least we have to do this walk and the one which writes the |
3136 | * refblocks; also, at least we have to do this loop here at least |
3137 | * twice (normally), first to do the allocations, and second to |
3138 | * determine that everything is correctly allocated, this then makes |
3139 | * three walks in total */ |
3140 | total_walks = MAX(walk_index + 2, 3); |
3141 | |
3142 | /* First, allocate the structures so they are present in the refcount |
3143 | * structures */ |
3144 | ret = walk_over_reftable(bs, &new_reftable, &new_reftable_index, |
3145 | &new_reftable_size, NULL, new_refblock_size, |
3146 | new_refcount_bits, &alloc_refblock, |
3147 | &new_allocation, NULL, status_cb, cb_opaque, |
3148 | walk_index++, total_walks, errp); |
3149 | if (ret < 0) { |
3150 | goto done; |
3151 | } |
3152 | |
3153 | new_reftable_index = 0; |
3154 | |
3155 | if (new_allocation) { |
3156 | if (new_reftable_offset) { |
3157 | qcow2_free_clusters(bs, new_reftable_offset, |
3158 | allocated_reftable_size * sizeof(uint64_t), |
3159 | QCOW2_DISCARD_NEVER); |
3160 | } |
3161 | |
3162 | new_reftable_offset = qcow2_alloc_clusters(bs, new_reftable_size * |
3163 | sizeof(uint64_t)); |
3164 | if (new_reftable_offset < 0) { |
3165 | error_setg_errno(errp, -new_reftable_offset, |
3166 | "Failed to allocate the new reftable" ); |
3167 | ret = new_reftable_offset; |
3168 | goto done; |
3169 | } |
3170 | allocated_reftable_size = new_reftable_size; |
3171 | } |
3172 | } while (new_allocation); |
3173 | |
3174 | /* Second, write the new refblocks */ |
3175 | ret = walk_over_reftable(bs, &new_reftable, &new_reftable_index, |
3176 | &new_reftable_size, new_refblock, |
3177 | new_refblock_size, new_refcount_bits, |
3178 | &flush_refblock, &new_allocation, new_set_refcount, |
3179 | status_cb, cb_opaque, walk_index, walk_index + 1, |
3180 | errp); |
3181 | if (ret < 0) { |
3182 | goto done; |
3183 | } |
3184 | assert(!new_allocation); |
3185 | |
3186 | |
3187 | /* Write the new reftable */ |
3188 | ret = qcow2_pre_write_overlap_check(bs, 0, new_reftable_offset, |
3189 | new_reftable_size * sizeof(uint64_t), |
3190 | false); |
3191 | if (ret < 0) { |
3192 | error_setg_errno(errp, -ret, "Overlap check failed" ); |
3193 | goto done; |
3194 | } |
3195 | |
3196 | for (i = 0; i < new_reftable_size; i++) { |
3197 | cpu_to_be64s(&new_reftable[i]); |
3198 | } |
3199 | |
3200 | ret = bdrv_pwrite(bs->file, new_reftable_offset, new_reftable, |
3201 | new_reftable_size * sizeof(uint64_t)); |
3202 | |
3203 | for (i = 0; i < new_reftable_size; i++) { |
3204 | be64_to_cpus(&new_reftable[i]); |
3205 | } |
3206 | |
3207 | if (ret < 0) { |
3208 | error_setg_errno(errp, -ret, "Failed to write the new reftable" ); |
3209 | goto done; |
3210 | } |
3211 | |
3212 | |
3213 | /* Empty the refcount cache */ |
3214 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
3215 | if (ret < 0) { |
3216 | error_setg_errno(errp, -ret, "Failed to flush the refblock cache" ); |
3217 | goto done; |
3218 | } |
3219 | |
3220 | /* Update the image header to point to the new reftable; this only updates |
3221 | * the fields which are relevant to qcow2_update_header(); other fields |
3222 | * such as s->refcount_table or s->refcount_bits stay stale for now |
3223 | * (because we have to restore everything if qcow2_update_header() fails) */ |
3224 | old_refcount_order = s->refcount_order; |
3225 | old_reftable_size = s->refcount_table_size; |
3226 | old_reftable_offset = s->refcount_table_offset; |
3227 | |
3228 | s->refcount_order = refcount_order; |
3229 | s->refcount_table_size = new_reftable_size; |
3230 | s->refcount_table_offset = new_reftable_offset; |
3231 | |
3232 | ret = qcow2_update_header(bs); |
3233 | if (ret < 0) { |
3234 | s->refcount_order = old_refcount_order; |
3235 | s->refcount_table_size = old_reftable_size; |
3236 | s->refcount_table_offset = old_reftable_offset; |
3237 | error_setg_errno(errp, -ret, "Failed to update the qcow2 header" ); |
3238 | goto done; |
3239 | } |
3240 | |
3241 | /* Now update the rest of the in-memory information */ |
3242 | old_reftable = s->refcount_table; |
3243 | s->refcount_table = new_reftable; |
3244 | update_max_refcount_table_index(s); |
3245 | |
3246 | s->refcount_bits = 1 << refcount_order; |
3247 | s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); |
3248 | s->refcount_max += s->refcount_max - 1; |
3249 | |
3250 | s->refcount_block_bits = s->cluster_bits - (refcount_order - 3); |
3251 | s->refcount_block_size = 1 << s->refcount_block_bits; |
3252 | |
3253 | s->get_refcount = new_get_refcount; |
3254 | s->set_refcount = new_set_refcount; |
3255 | |
3256 | /* For cleaning up all old refblocks and the old reftable below the "done" |
3257 | * label */ |
3258 | new_reftable = old_reftable; |
3259 | new_reftable_size = old_reftable_size; |
3260 | new_reftable_offset = old_reftable_offset; |
3261 | |
3262 | done: |
3263 | if (new_reftable) { |
3264 | /* On success, new_reftable actually points to the old reftable (and |
3265 | * new_reftable_size is the old reftable's size); but that is just |
3266 | * fine */ |
3267 | for (i = 0; i < new_reftable_size; i++) { |
3268 | uint64_t offset = new_reftable[i] & REFT_OFFSET_MASK; |
3269 | if (offset) { |
3270 | qcow2_free_clusters(bs, offset, s->cluster_size, |
3271 | QCOW2_DISCARD_OTHER); |
3272 | } |
3273 | } |
3274 | g_free(new_reftable); |
3275 | |
3276 | if (new_reftable_offset > 0) { |
3277 | qcow2_free_clusters(bs, new_reftable_offset, |
3278 | new_reftable_size * sizeof(uint64_t), |
3279 | QCOW2_DISCARD_OTHER); |
3280 | } |
3281 | } |
3282 | |
3283 | qemu_vfree(new_refblock); |
3284 | return ret; |
3285 | } |
3286 | |
3287 | static int64_t get_refblock_offset(BlockDriverState *bs, uint64_t offset) |
3288 | { |
3289 | BDRVQcow2State *s = bs->opaque; |
3290 | uint32_t index = offset_to_reftable_index(s, offset); |
3291 | int64_t covering_refblock_offset = 0; |
3292 | |
3293 | if (index < s->refcount_table_size) { |
3294 | covering_refblock_offset = s->refcount_table[index] & REFT_OFFSET_MASK; |
3295 | } |
3296 | if (!covering_refblock_offset) { |
3297 | qcow2_signal_corruption(bs, true, -1, -1, "Refblock at %#" PRIx64 " is " |
3298 | "not covered by the refcount structures" , |
3299 | offset); |
3300 | return -EIO; |
3301 | } |
3302 | |
3303 | return covering_refblock_offset; |
3304 | } |
3305 | |
3306 | static int qcow2_discard_refcount_block(BlockDriverState *bs, |
3307 | uint64_t discard_block_offs) |
3308 | { |
3309 | BDRVQcow2State *s = bs->opaque; |
3310 | int64_t refblock_offs; |
3311 | uint64_t cluster_index = discard_block_offs >> s->cluster_bits; |
3312 | uint32_t block_index = cluster_index & (s->refcount_block_size - 1); |
3313 | void *refblock; |
3314 | int ret; |
3315 | |
3316 | refblock_offs = get_refblock_offset(bs, discard_block_offs); |
3317 | if (refblock_offs < 0) { |
3318 | return refblock_offs; |
3319 | } |
3320 | |
3321 | assert(discard_block_offs != 0); |
3322 | |
3323 | ret = qcow2_cache_get(bs, s->refcount_block_cache, refblock_offs, |
3324 | &refblock); |
3325 | if (ret < 0) { |
3326 | return ret; |
3327 | } |
3328 | |
3329 | if (s->get_refcount(refblock, block_index) != 1) { |
3330 | qcow2_signal_corruption(bs, true, -1, -1, "Invalid refcount:" |
3331 | " refblock offset %#" PRIx64 |
3332 | ", reftable index %u" |
3333 | ", block offset %#" PRIx64 |
3334 | ", refcount %#" PRIx64, |
3335 | refblock_offs, |
3336 | offset_to_reftable_index(s, discard_block_offs), |
3337 | discard_block_offs, |
3338 | s->get_refcount(refblock, block_index)); |
3339 | qcow2_cache_put(s->refcount_block_cache, &refblock); |
3340 | return -EINVAL; |
3341 | } |
3342 | s->set_refcount(refblock, block_index, 0); |
3343 | |
3344 | qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refblock); |
3345 | |
3346 | qcow2_cache_put(s->refcount_block_cache, &refblock); |
3347 | |
3348 | if (cluster_index < s->free_cluster_index) { |
3349 | s->free_cluster_index = cluster_index; |
3350 | } |
3351 | |
3352 | refblock = qcow2_cache_is_table_offset(s->refcount_block_cache, |
3353 | discard_block_offs); |
3354 | if (refblock) { |
3355 | /* discard refblock from the cache if refblock is cached */ |
3356 | qcow2_cache_discard(s->refcount_block_cache, refblock); |
3357 | } |
3358 | update_refcount_discard(bs, discard_block_offs, s->cluster_size); |
3359 | |
3360 | return 0; |
3361 | } |
3362 | |
3363 | int qcow2_shrink_reftable(BlockDriverState *bs) |
3364 | { |
3365 | BDRVQcow2State *s = bs->opaque; |
3366 | uint64_t *reftable_tmp = |
3367 | g_malloc(s->refcount_table_size * sizeof(uint64_t)); |
3368 | int i, ret; |
3369 | |
3370 | for (i = 0; i < s->refcount_table_size; i++) { |
3371 | int64_t refblock_offs = s->refcount_table[i] & REFT_OFFSET_MASK; |
3372 | void *refblock; |
3373 | bool unused_block; |
3374 | |
3375 | if (refblock_offs == 0) { |
3376 | reftable_tmp[i] = 0; |
3377 | continue; |
3378 | } |
3379 | ret = qcow2_cache_get(bs, s->refcount_block_cache, refblock_offs, |
3380 | &refblock); |
3381 | if (ret < 0) { |
3382 | goto out; |
3383 | } |
3384 | |
3385 | /* the refblock has own reference */ |
3386 | if (i == offset_to_reftable_index(s, refblock_offs)) { |
3387 | uint64_t block_index = (refblock_offs >> s->cluster_bits) & |
3388 | (s->refcount_block_size - 1); |
3389 | uint64_t refcount = s->get_refcount(refblock, block_index); |
3390 | |
3391 | s->set_refcount(refblock, block_index, 0); |
3392 | |
3393 | unused_block = buffer_is_zero(refblock, s->cluster_size); |
3394 | |
3395 | s->set_refcount(refblock, block_index, refcount); |
3396 | } else { |
3397 | unused_block = buffer_is_zero(refblock, s->cluster_size); |
3398 | } |
3399 | qcow2_cache_put(s->refcount_block_cache, &refblock); |
3400 | |
3401 | reftable_tmp[i] = unused_block ? 0 : cpu_to_be64(s->refcount_table[i]); |
3402 | } |
3403 | |
3404 | ret = bdrv_pwrite_sync(bs->file, s->refcount_table_offset, reftable_tmp, |
3405 | s->refcount_table_size * sizeof(uint64_t)); |
3406 | /* |
3407 | * If the write in the reftable failed the image may contain a partially |
3408 | * overwritten reftable. In this case it would be better to clear the |
3409 | * reftable in memory to avoid possible image corruption. |
3410 | */ |
3411 | for (i = 0; i < s->refcount_table_size; i++) { |
3412 | if (s->refcount_table[i] && !reftable_tmp[i]) { |
3413 | if (ret == 0) { |
3414 | ret = qcow2_discard_refcount_block(bs, s->refcount_table[i] & |
3415 | REFT_OFFSET_MASK); |
3416 | } |
3417 | s->refcount_table[i] = 0; |
3418 | } |
3419 | } |
3420 | |
3421 | if (!s->cache_discards) { |
3422 | qcow2_process_discards(bs, ret); |
3423 | } |
3424 | |
3425 | out: |
3426 | g_free(reftable_tmp); |
3427 | return ret; |
3428 | } |
3429 | |
3430 | int64_t qcow2_get_last_cluster(BlockDriverState *bs, int64_t size) |
3431 | { |
3432 | BDRVQcow2State *s = bs->opaque; |
3433 | int64_t i; |
3434 | |
3435 | for (i = size_to_clusters(s, size) - 1; i >= 0; i--) { |
3436 | uint64_t refcount; |
3437 | int ret = qcow2_get_refcount(bs, i, &refcount); |
3438 | if (ret < 0) { |
3439 | fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n" , |
3440 | i, strerror(-ret)); |
3441 | return ret; |
3442 | } |
3443 | if (refcount > 0) { |
3444 | return i; |
3445 | } |
3446 | } |
3447 | qcow2_signal_corruption(bs, true, -1, -1, |
3448 | "There are no references in the refcount table." ); |
3449 | return -EIO; |
3450 | } |
3451 | |
3452 | int qcow2_detect_metadata_preallocation(BlockDriverState *bs) |
3453 | { |
3454 | BDRVQcow2State *s = bs->opaque; |
3455 | int64_t i, end_cluster, cluster_count = 0, threshold; |
3456 | int64_t file_length, real_allocation, real_clusters; |
3457 | |
3458 | file_length = bdrv_getlength(bs->file->bs); |
3459 | if (file_length < 0) { |
3460 | return file_length; |
3461 | } |
3462 | |
3463 | real_allocation = bdrv_get_allocated_file_size(bs->file->bs); |
3464 | if (real_allocation < 0) { |
3465 | return real_allocation; |
3466 | } |
3467 | |
3468 | real_clusters = real_allocation / s->cluster_size; |
3469 | threshold = MAX(real_clusters * 10 / 9, real_clusters + 2); |
3470 | |
3471 | end_cluster = size_to_clusters(s, file_length); |
3472 | for (i = 0; i < end_cluster && cluster_count < threshold; i++) { |
3473 | uint64_t refcount; |
3474 | int ret = qcow2_get_refcount(bs, i, &refcount); |
3475 | if (ret < 0) { |
3476 | return ret; |
3477 | } |
3478 | cluster_count += !!refcount; |
3479 | } |
3480 | |
3481 | return cluster_count >= threshold; |
3482 | } |
3483 | |