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qcow2: Fix error handling for immediate backing file read failure
[qemu.git] / block / qcow2.c
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 #include "qemu-common.h"
25 #include "block_int.h"
26 #include "module.h"
27 #include <zlib.h>
28 #include "aes.h"
29 #include "block/qcow2.h"
30 #include "qemu-error.h"
31
32 /*
33 Differences with QCOW:
34
35 - Support for multiple incremental snapshots.
36 - Memory management by reference counts.
37 - Clusters which have a reference count of one have the bit
38 QCOW_OFLAG_COPIED to optimize write performance.
39 - Size of compressed clusters is stored in sectors to reduce bit usage
40 in the cluster offsets.
41 - Support for storing additional data (such as the VM state) in the
42 snapshots.
43 - If a backing store is used, the cluster size is not constrained
44 (could be backported to QCOW).
45 - L2 tables have always a size of one cluster.
46 */
47
48
49 typedef struct {
50 uint32_t magic;
51 uint32_t len;
52 } QCowExtension;
53 #define QCOW2_EXT_MAGIC_END 0
54 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
55
56 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
57 {
58 const QCowHeader *cow_header = (const void *)buf;
59
60 if (buf_size >= sizeof(QCowHeader) &&
61 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
62 be32_to_cpu(cow_header->version) == QCOW_VERSION)
63 return 100;
64 else
65 return 0;
66 }
67
68
69 /*
70 * read qcow2 extension and fill bs
71 * start reading from start_offset
72 * finish reading upon magic of value 0 or when end_offset reached
73 * unknown magic is skipped (future extension this version knows nothing about)
74 * return 0 upon success, non-0 otherwise
75 */
76 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
77 uint64_t end_offset)
78 {
79 QCowExtension ext;
80 uint64_t offset;
81
82 #ifdef DEBUG_EXT
83 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
84 #endif
85 offset = start_offset;
86 while (offset < end_offset) {
87
88 #ifdef DEBUG_EXT
89 /* Sanity check */
90 if (offset > s->cluster_size)
91 printf("qcow2_read_extension: suspicious offset %lu\n", offset);
92
93 printf("attemting to read extended header in offset %lu\n", offset);
94 #endif
95
96 if (bdrv_pread(bs->file, offset, &ext, sizeof(ext)) != sizeof(ext)) {
97 fprintf(stderr, "qcow2_read_extension: ERROR: "
98 "pread fail from offset %" PRIu64 "\n",
99 offset);
100 return 1;
101 }
102 be32_to_cpus(&ext.magic);
103 be32_to_cpus(&ext.len);
104 offset += sizeof(ext);
105 #ifdef DEBUG_EXT
106 printf("ext.magic = 0x%x\n", ext.magic);
107 #endif
108 switch (ext.magic) {
109 case QCOW2_EXT_MAGIC_END:
110 return 0;
111
112 case QCOW2_EXT_MAGIC_BACKING_FORMAT:
113 if (ext.len >= sizeof(bs->backing_format)) {
114 fprintf(stderr, "ERROR: ext_backing_format: len=%u too large"
115 " (>=%zu)\n",
116 ext.len, sizeof(bs->backing_format));
117 return 2;
118 }
119 if (bdrv_pread(bs->file, offset , bs->backing_format,
120 ext.len) != ext.len)
121 return 3;
122 bs->backing_format[ext.len] = '\0';
123 #ifdef DEBUG_EXT
124 printf("Qcow2: Got format extension %s\n", bs->backing_format);
125 #endif
126 offset = ((offset + ext.len + 7) & ~7);
127 break;
128
129 default:
130 /* unknown magic -- just skip it */
131 offset = ((offset + ext.len + 7) & ~7);
132 break;
133 }
134 }
135
136 return 0;
137 }
138
139
140 static int qcow2_open(BlockDriverState *bs, int flags)
141 {
142 BDRVQcowState *s = bs->opaque;
143 int len, i, ret = 0;
144 QCowHeader header;
145 uint64_t ext_end;
146 bool writethrough;
147
148 ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
149 if (ret < 0) {
150 goto fail;
151 }
152 be32_to_cpus(&header.magic);
153 be32_to_cpus(&header.version);
154 be64_to_cpus(&header.backing_file_offset);
155 be32_to_cpus(&header.backing_file_size);
156 be64_to_cpus(&header.size);
157 be32_to_cpus(&header.cluster_bits);
158 be32_to_cpus(&header.crypt_method);
159 be64_to_cpus(&header.l1_table_offset);
160 be32_to_cpus(&header.l1_size);
161 be64_to_cpus(&header.refcount_table_offset);
162 be32_to_cpus(&header.refcount_table_clusters);
163 be64_to_cpus(&header.snapshots_offset);
164 be32_to_cpus(&header.nb_snapshots);
165
166 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION) {
167 ret = -EINVAL;
168 goto fail;
169 }
170 if (header.cluster_bits < MIN_CLUSTER_BITS ||
171 header.cluster_bits > MAX_CLUSTER_BITS) {
172 ret = -EINVAL;
173 goto fail;
174 }
175 if (header.crypt_method > QCOW_CRYPT_AES) {
176 ret = -EINVAL;
177 goto fail;
178 }
179 s->crypt_method_header = header.crypt_method;
180 if (s->crypt_method_header) {
181 bs->encrypted = 1;
182 }
183 s->cluster_bits = header.cluster_bits;
184 s->cluster_size = 1 << s->cluster_bits;
185 s->cluster_sectors = 1 << (s->cluster_bits - 9);
186 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
187 s->l2_size = 1 << s->l2_bits;
188 bs->total_sectors = header.size / 512;
189 s->csize_shift = (62 - (s->cluster_bits - 8));
190 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
191 s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
192 s->refcount_table_offset = header.refcount_table_offset;
193 s->refcount_table_size =
194 header.refcount_table_clusters << (s->cluster_bits - 3);
195
196 s->snapshots_offset = header.snapshots_offset;
197 s->nb_snapshots = header.nb_snapshots;
198
199 /* read the level 1 table */
200 s->l1_size = header.l1_size;
201 s->l1_vm_state_index = size_to_l1(s, header.size);
202 /* the L1 table must contain at least enough entries to put
203 header.size bytes */
204 if (s->l1_size < s->l1_vm_state_index) {
205 ret = -EINVAL;
206 goto fail;
207 }
208 s->l1_table_offset = header.l1_table_offset;
209 if (s->l1_size > 0) {
210 s->l1_table = qemu_mallocz(
211 align_offset(s->l1_size * sizeof(uint64_t), 512));
212 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
213 s->l1_size * sizeof(uint64_t));
214 if (ret < 0) {
215 goto fail;
216 }
217 for(i = 0;i < s->l1_size; i++) {
218 be64_to_cpus(&s->l1_table[i]);
219 }
220 }
221
222 /* alloc L2 table/refcount block cache */
223 writethrough = ((flags & BDRV_O_CACHE_MASK) == 0);
224 s->l2_table_cache = qcow2_cache_create(bs, L2_CACHE_SIZE, writethrough);
225 s->refcount_block_cache = qcow2_cache_create(bs, REFCOUNT_CACHE_SIZE,
226 writethrough);
227
228 s->cluster_cache = qemu_malloc(s->cluster_size);
229 /* one more sector for decompressed data alignment */
230 s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
231 + 512);
232 s->cluster_cache_offset = -1;
233
234 ret = qcow2_refcount_init(bs);
235 if (ret != 0) {
236 goto fail;
237 }
238
239 QLIST_INIT(&s->cluster_allocs);
240
241 /* read qcow2 extensions */
242 if (header.backing_file_offset) {
243 ext_end = header.backing_file_offset;
244 } else {
245 ext_end = s->cluster_size;
246 }
247 if (qcow2_read_extensions(bs, sizeof(header), ext_end)) {
248 ret = -EINVAL;
249 goto fail;
250 }
251
252 /* read the backing file name */
253 if (header.backing_file_offset != 0) {
254 len = header.backing_file_size;
255 if (len > 1023) {
256 len = 1023;
257 }
258 ret = bdrv_pread(bs->file, header.backing_file_offset,
259 bs->backing_file, len);
260 if (ret < 0) {
261 goto fail;
262 }
263 bs->backing_file[len] = '\0';
264 }
265 if (qcow2_read_snapshots(bs) < 0) {
266 ret = -EINVAL;
267 goto fail;
268 }
269
270 #ifdef DEBUG_ALLOC
271 qcow2_check_refcounts(bs);
272 #endif
273 return ret;
274
275 fail:
276 qcow2_free_snapshots(bs);
277 qcow2_refcount_close(bs);
278 qemu_free(s->l1_table);
279 if (s->l2_table_cache) {
280 qcow2_cache_destroy(bs, s->l2_table_cache);
281 }
282 qemu_free(s->cluster_cache);
283 qemu_free(s->cluster_data);
284 return ret;
285 }
286
287 static int qcow2_set_key(BlockDriverState *bs, const char *key)
288 {
289 BDRVQcowState *s = bs->opaque;
290 uint8_t keybuf[16];
291 int len, i;
292
293 memset(keybuf, 0, 16);
294 len = strlen(key);
295 if (len > 16)
296 len = 16;
297 /* XXX: we could compress the chars to 7 bits to increase
298 entropy */
299 for(i = 0;i < len;i++) {
300 keybuf[i] = key[i];
301 }
302 s->crypt_method = s->crypt_method_header;
303
304 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
305 return -1;
306 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
307 return -1;
308 #if 0
309 /* test */
310 {
311 uint8_t in[16];
312 uint8_t out[16];
313 uint8_t tmp[16];
314 for(i=0;i<16;i++)
315 in[i] = i;
316 AES_encrypt(in, tmp, &s->aes_encrypt_key);
317 AES_decrypt(tmp, out, &s->aes_decrypt_key);
318 for(i = 0; i < 16; i++)
319 printf(" %02x", tmp[i]);
320 printf("\n");
321 for(i = 0; i < 16; i++)
322 printf(" %02x", out[i]);
323 printf("\n");
324 }
325 #endif
326 return 0;
327 }
328
329 static int qcow2_is_allocated(BlockDriverState *bs, int64_t sector_num,
330 int nb_sectors, int *pnum)
331 {
332 uint64_t cluster_offset;
333 int ret;
334
335 *pnum = nb_sectors;
336 /* FIXME We can get errors here, but the bdrv_is_allocated interface can't
337 * pass them on today */
338 ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset);
339 if (ret < 0) {
340 *pnum = 0;
341 }
342
343 return (cluster_offset != 0);
344 }
345
346 /* handle reading after the end of the backing file */
347 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
348 int64_t sector_num, int nb_sectors)
349 {
350 int n1;
351 if ((sector_num + nb_sectors) <= bs->total_sectors)
352 return nb_sectors;
353 if (sector_num >= bs->total_sectors)
354 n1 = 0;
355 else
356 n1 = bs->total_sectors - sector_num;
357
358 qemu_iovec_memset_skip(qiov, 0, 512 * (nb_sectors - n1), 512 * n1);
359
360 return n1;
361 }
362
363 typedef struct QCowAIOCB {
364 BlockDriverAIOCB common;
365 int64_t sector_num;
366 QEMUIOVector *qiov;
367 int remaining_sectors;
368 int cur_nr_sectors; /* number of sectors in current iteration */
369 uint64_t bytes_done;
370 uint64_t cluster_offset;
371 uint8_t *cluster_data;
372 BlockDriverAIOCB *hd_aiocb;
373 QEMUIOVector hd_qiov;
374 QEMUBH *bh;
375 QCowL2Meta l2meta;
376 QLIST_ENTRY(QCowAIOCB) next_depend;
377 } QCowAIOCB;
378
379 static void qcow2_aio_cancel(BlockDriverAIOCB *blockacb)
380 {
381 QCowAIOCB *acb = container_of(blockacb, QCowAIOCB, common);
382 if (acb->hd_aiocb)
383 bdrv_aio_cancel(acb->hd_aiocb);
384 qemu_aio_release(acb);
385 }
386
387 static AIOPool qcow2_aio_pool = {
388 .aiocb_size = sizeof(QCowAIOCB),
389 .cancel = qcow2_aio_cancel,
390 };
391
392 static void qcow2_aio_read_cb(void *opaque, int ret);
393 static void qcow2_aio_read_bh(void *opaque)
394 {
395 QCowAIOCB *acb = opaque;
396 qemu_bh_delete(acb->bh);
397 acb->bh = NULL;
398 qcow2_aio_read_cb(opaque, 0);
399 }
400
401 static int qcow2_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb)
402 {
403 if (acb->bh)
404 return -EIO;
405
406 acb->bh = qemu_bh_new(cb, acb);
407 if (!acb->bh)
408 return -EIO;
409
410 qemu_bh_schedule(acb->bh);
411
412 return 0;
413 }
414
415 static void qcow2_aio_read_cb(void *opaque, int ret)
416 {
417 QCowAIOCB *acb = opaque;
418 BlockDriverState *bs = acb->common.bs;
419 BDRVQcowState *s = bs->opaque;
420 int index_in_cluster, n1;
421
422 acb->hd_aiocb = NULL;
423 if (ret < 0)
424 goto done;
425
426 /* post process the read buffer */
427 if (!acb->cluster_offset) {
428 /* nothing to do */
429 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
430 /* nothing to do */
431 } else {
432 if (s->crypt_method) {
433 qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data,
434 acb->cluster_data, acb->cur_nr_sectors, 0, &s->aes_decrypt_key);
435 qemu_iovec_reset(&acb->hd_qiov);
436 qemu_iovec_copy(&acb->hd_qiov, acb->qiov, acb->bytes_done,
437 acb->cur_nr_sectors * 512);
438 qemu_iovec_from_buffer(&acb->hd_qiov, acb->cluster_data,
439 512 * acb->cur_nr_sectors);
440 }
441 }
442
443 acb->remaining_sectors -= acb->cur_nr_sectors;
444 acb->sector_num += acb->cur_nr_sectors;
445 acb->bytes_done += acb->cur_nr_sectors * 512;
446
447 if (acb->remaining_sectors == 0) {
448 /* request completed */
449 ret = 0;
450 goto done;
451 }
452
453 /* prepare next AIO request */
454 acb->cur_nr_sectors = acb->remaining_sectors;
455 if (s->crypt_method) {
456 acb->cur_nr_sectors = MIN(acb->cur_nr_sectors,
457 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
458 }
459
460 ret = qcow2_get_cluster_offset(bs, acb->sector_num << 9,
461 &acb->cur_nr_sectors, &acb->cluster_offset);
462 if (ret < 0) {
463 goto done;
464 }
465
466 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
467
468 qemu_iovec_reset(&acb->hd_qiov);
469 qemu_iovec_copy(&acb->hd_qiov, acb->qiov, acb->bytes_done,
470 acb->cur_nr_sectors * 512);
471
472 if (!acb->cluster_offset) {
473
474 if (bs->backing_hd) {
475 /* read from the base image */
476 n1 = qcow2_backing_read1(bs->backing_hd, &acb->hd_qiov,
477 acb->sector_num, acb->cur_nr_sectors);
478 if (n1 > 0) {
479 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
480 acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
481 &acb->hd_qiov, n1, qcow2_aio_read_cb, acb);
482 if (acb->hd_aiocb == NULL) {
483 ret = -EIO;
484 goto done;
485 }
486 } else {
487 ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb);
488 if (ret < 0)
489 goto done;
490 }
491 } else {
492 /* Note: in this case, no need to wait */
493 qemu_iovec_memset(&acb->hd_qiov, 0, 512 * acb->cur_nr_sectors);
494 ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb);
495 if (ret < 0)
496 goto done;
497 }
498 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
499 /* add AIO support for compressed blocks ? */
500 if (qcow2_decompress_cluster(bs, acb->cluster_offset) < 0)
501 goto done;
502
503 qemu_iovec_from_buffer(&acb->hd_qiov,
504 s->cluster_cache + index_in_cluster * 512,
505 512 * acb->cur_nr_sectors);
506
507 ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb);
508 if (ret < 0)
509 goto done;
510 } else {
511 if ((acb->cluster_offset & 511) != 0) {
512 ret = -EIO;
513 goto done;
514 }
515
516 if (s->crypt_method) {
517 /*
518 * For encrypted images, read everything into a temporary
519 * contiguous buffer on which the AES functions can work.
520 */
521 if (!acb->cluster_data) {
522 acb->cluster_data =
523 qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
524 }
525
526 assert(acb->cur_nr_sectors <=
527 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
528 qemu_iovec_reset(&acb->hd_qiov);
529 qemu_iovec_add(&acb->hd_qiov, acb->cluster_data,
530 512 * acb->cur_nr_sectors);
531 }
532
533 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
534 acb->hd_aiocb = bdrv_aio_readv(bs->file,
535 (acb->cluster_offset >> 9) + index_in_cluster,
536 &acb->hd_qiov, acb->cur_nr_sectors,
537 qcow2_aio_read_cb, acb);
538 if (acb->hd_aiocb == NULL) {
539 ret = -EIO;
540 goto done;
541 }
542 }
543
544 return;
545 done:
546 acb->common.cb(acb->common.opaque, ret);
547 qemu_iovec_destroy(&acb->hd_qiov);
548 qemu_aio_release(acb);
549 }
550
551 static QCowAIOCB *qcow2_aio_setup(BlockDriverState *bs, int64_t sector_num,
552 QEMUIOVector *qiov, int nb_sectors,
553 BlockDriverCompletionFunc *cb,
554 void *opaque, int is_write)
555 {
556 QCowAIOCB *acb;
557
558 acb = qemu_aio_get(&qcow2_aio_pool, bs, cb, opaque);
559 if (!acb)
560 return NULL;
561 acb->hd_aiocb = NULL;
562 acb->sector_num = sector_num;
563 acb->qiov = qiov;
564
565 qemu_iovec_init(&acb->hd_qiov, qiov->niov);
566
567 acb->bytes_done = 0;
568 acb->remaining_sectors = nb_sectors;
569 acb->cur_nr_sectors = 0;
570 acb->cluster_offset = 0;
571 acb->l2meta.nb_clusters = 0;
572 QLIST_INIT(&acb->l2meta.dependent_requests);
573 return acb;
574 }
575
576 static BlockDriverAIOCB *qcow2_aio_readv(BlockDriverState *bs,
577 int64_t sector_num,
578 QEMUIOVector *qiov, int nb_sectors,
579 BlockDriverCompletionFunc *cb,
580 void *opaque)
581 {
582 QCowAIOCB *acb;
583
584 acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
585 if (!acb)
586 return NULL;
587
588 qcow2_aio_read_cb(acb, 0);
589 return &acb->common;
590 }
591
592 static void qcow2_aio_write_cb(void *opaque, int ret);
593
594 static void run_dependent_requests(QCowL2Meta *m)
595 {
596 QCowAIOCB *req;
597 QCowAIOCB *next;
598
599 /* Take the request off the list of running requests */
600 if (m->nb_clusters != 0) {
601 QLIST_REMOVE(m, next_in_flight);
602 }
603
604 /* Restart all dependent requests */
605 QLIST_FOREACH_SAFE(req, &m->dependent_requests, next_depend, next) {
606 qcow2_aio_write_cb(req, 0);
607 }
608
609 /* Empty the list for the next part of the request */
610 QLIST_INIT(&m->dependent_requests);
611 }
612
613 static void qcow2_aio_write_cb(void *opaque, int ret)
614 {
615 QCowAIOCB *acb = opaque;
616 BlockDriverState *bs = acb->common.bs;
617 BDRVQcowState *s = bs->opaque;
618 int index_in_cluster;
619 int n_end;
620
621 acb->hd_aiocb = NULL;
622
623 if (ret >= 0) {
624 ret = qcow2_alloc_cluster_link_l2(bs, &acb->l2meta);
625 }
626
627 run_dependent_requests(&acb->l2meta);
628
629 if (ret < 0)
630 goto done;
631
632 acb->remaining_sectors -= acb->cur_nr_sectors;
633 acb->sector_num += acb->cur_nr_sectors;
634 acb->bytes_done += acb->cur_nr_sectors * 512;
635
636 if (acb->remaining_sectors == 0) {
637 /* request completed */
638 ret = 0;
639 goto done;
640 }
641
642 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
643 n_end = index_in_cluster + acb->remaining_sectors;
644 if (s->crypt_method &&
645 n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
646 n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
647
648 ret = qcow2_alloc_cluster_offset(bs, acb->sector_num << 9,
649 index_in_cluster, n_end, &acb->cur_nr_sectors, &acb->l2meta);
650 if (ret < 0) {
651 goto done;
652 }
653
654 acb->cluster_offset = acb->l2meta.cluster_offset;
655
656 /* Need to wait for another request? If so, we are done for now. */
657 if (acb->l2meta.nb_clusters == 0 && acb->l2meta.depends_on != NULL) {
658 QLIST_INSERT_HEAD(&acb->l2meta.depends_on->dependent_requests,
659 acb, next_depend);
660 return;
661 }
662
663 assert((acb->cluster_offset & 511) == 0);
664
665 qemu_iovec_reset(&acb->hd_qiov);
666 qemu_iovec_copy(&acb->hd_qiov, acb->qiov, acb->bytes_done,
667 acb->cur_nr_sectors * 512);
668
669 if (s->crypt_method) {
670 if (!acb->cluster_data) {
671 acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS *
672 s->cluster_size);
673 }
674
675 assert(acb->hd_qiov.size <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
676 qemu_iovec_to_buffer(&acb->hd_qiov, acb->cluster_data);
677
678 qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data,
679 acb->cluster_data, acb->cur_nr_sectors, 1, &s->aes_encrypt_key);
680
681 qemu_iovec_reset(&acb->hd_qiov);
682 qemu_iovec_add(&acb->hd_qiov, acb->cluster_data,
683 acb->cur_nr_sectors * 512);
684 }
685
686 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
687 acb->hd_aiocb = bdrv_aio_writev(bs->file,
688 (acb->cluster_offset >> 9) + index_in_cluster,
689 &acb->hd_qiov, acb->cur_nr_sectors,
690 qcow2_aio_write_cb, acb);
691 if (acb->hd_aiocb == NULL) {
692 ret = -EIO;
693 goto fail;
694 }
695
696 return;
697
698 fail:
699 if (acb->l2meta.nb_clusters != 0) {
700 QLIST_REMOVE(&acb->l2meta, next_in_flight);
701 }
702 done:
703 acb->common.cb(acb->common.opaque, ret);
704 qemu_iovec_destroy(&acb->hd_qiov);
705 qemu_aio_release(acb);
706 }
707
708 static BlockDriverAIOCB *qcow2_aio_writev(BlockDriverState *bs,
709 int64_t sector_num,
710 QEMUIOVector *qiov, int nb_sectors,
711 BlockDriverCompletionFunc *cb,
712 void *opaque)
713 {
714 BDRVQcowState *s = bs->opaque;
715 QCowAIOCB *acb;
716
717 s->cluster_cache_offset = -1; /* disable compressed cache */
718
719 acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
720 if (!acb)
721 return NULL;
722
723 qcow2_aio_write_cb(acb, 0);
724 return &acb->common;
725 }
726
727 static void qcow2_close(BlockDriverState *bs)
728 {
729 BDRVQcowState *s = bs->opaque;
730 qemu_free(s->l1_table);
731
732 qcow2_cache_flush(bs, s->l2_table_cache);
733 qcow2_cache_flush(bs, s->refcount_block_cache);
734
735 qcow2_cache_destroy(bs, s->l2_table_cache);
736 qcow2_cache_destroy(bs, s->refcount_block_cache);
737
738 qemu_free(s->cluster_cache);
739 qemu_free(s->cluster_data);
740 qcow2_refcount_close(bs);
741 }
742
743 /*
744 * Updates the variable length parts of the qcow2 header, i.e. the backing file
745 * name and all extensions. qcow2 was not designed to allow such changes, so if
746 * we run out of space (we can only use the first cluster) this function may
747 * fail.
748 *
749 * Returns 0 on success, -errno in error cases.
750 */
751 static int qcow2_update_ext_header(BlockDriverState *bs,
752 const char *backing_file, const char *backing_fmt)
753 {
754 size_t backing_file_len = 0;
755 size_t backing_fmt_len = 0;
756 BDRVQcowState *s = bs->opaque;
757 QCowExtension ext_backing_fmt = {0, 0};
758 int ret;
759
760 /* Backing file format doesn't make sense without a backing file */
761 if (backing_fmt && !backing_file) {
762 return -EINVAL;
763 }
764
765 /* Prepare the backing file format extension if needed */
766 if (backing_fmt) {
767 ext_backing_fmt.len = cpu_to_be32(strlen(backing_fmt));
768 ext_backing_fmt.magic = cpu_to_be32(QCOW2_EXT_MAGIC_BACKING_FORMAT);
769 backing_fmt_len = ((sizeof(ext_backing_fmt)
770 + strlen(backing_fmt) + 7) & ~7);
771 }
772
773 /* Check if we can fit the new header into the first cluster */
774 if (backing_file) {
775 backing_file_len = strlen(backing_file);
776 }
777
778 size_t header_size = sizeof(QCowHeader) + backing_file_len
779 + backing_fmt_len;
780
781 if (header_size > s->cluster_size) {
782 return -ENOSPC;
783 }
784
785 /* Rewrite backing file name and qcow2 extensions */
786 size_t ext_size = header_size - sizeof(QCowHeader);
787 uint8_t buf[ext_size];
788 size_t offset = 0;
789 size_t backing_file_offset = 0;
790
791 if (backing_file) {
792 if (backing_fmt) {
793 int padding = backing_fmt_len -
794 (sizeof(ext_backing_fmt) + strlen(backing_fmt));
795
796 memcpy(buf + offset, &ext_backing_fmt, sizeof(ext_backing_fmt));
797 offset += sizeof(ext_backing_fmt);
798
799 memcpy(buf + offset, backing_fmt, strlen(backing_fmt));
800 offset += strlen(backing_fmt);
801
802 memset(buf + offset, 0, padding);
803 offset += padding;
804 }
805
806 memcpy(buf + offset, backing_file, backing_file_len);
807 backing_file_offset = sizeof(QCowHeader) + offset;
808 }
809
810 ret = bdrv_pwrite_sync(bs->file, sizeof(QCowHeader), buf, ext_size);
811 if (ret < 0) {
812 goto fail;
813 }
814
815 /* Update header fields */
816 uint64_t be_backing_file_offset = cpu_to_be64(backing_file_offset);
817 uint32_t be_backing_file_size = cpu_to_be32(backing_file_len);
818
819 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, backing_file_offset),
820 &be_backing_file_offset, sizeof(uint64_t));
821 if (ret < 0) {
822 goto fail;
823 }
824
825 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, backing_file_size),
826 &be_backing_file_size, sizeof(uint32_t));
827 if (ret < 0) {
828 goto fail;
829 }
830
831 ret = 0;
832 fail:
833 return ret;
834 }
835
836 static int qcow2_change_backing_file(BlockDriverState *bs,
837 const char *backing_file, const char *backing_fmt)
838 {
839 return qcow2_update_ext_header(bs, backing_file, backing_fmt);
840 }
841
842 static int preallocate(BlockDriverState *bs)
843 {
844 uint64_t nb_sectors;
845 uint64_t offset;
846 int num;
847 int ret;
848 QCowL2Meta meta;
849
850 nb_sectors = bdrv_getlength(bs) >> 9;
851 offset = 0;
852 QLIST_INIT(&meta.dependent_requests);
853 meta.cluster_offset = 0;
854
855 while (nb_sectors) {
856 num = MIN(nb_sectors, INT_MAX >> 9);
857 ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num, &meta);
858 if (ret < 0) {
859 return ret;
860 }
861
862 ret = qcow2_alloc_cluster_link_l2(bs, &meta);
863 if (ret < 0) {
864 qcow2_free_any_clusters(bs, meta.cluster_offset, meta.nb_clusters);
865 return ret;
866 }
867
868 /* There are no dependent requests, but we need to remove our request
869 * from the list of in-flight requests */
870 run_dependent_requests(&meta);
871
872 /* TODO Preallocate data if requested */
873
874 nb_sectors -= num;
875 offset += num << 9;
876 }
877
878 /*
879 * It is expected that the image file is large enough to actually contain
880 * all of the allocated clusters (otherwise we get failing reads after
881 * EOF). Extend the image to the last allocated sector.
882 */
883 if (meta.cluster_offset != 0) {
884 uint8_t buf[512];
885 memset(buf, 0, 512);
886 ret = bdrv_write(bs->file, (meta.cluster_offset >> 9) + num - 1, buf, 1);
887 if (ret < 0) {
888 return ret;
889 }
890 }
891
892 return 0;
893 }
894
895 static int qcow2_create2(const char *filename, int64_t total_size,
896 const char *backing_file, const char *backing_format,
897 int flags, size_t cluster_size, int prealloc,
898 QEMUOptionParameter *options)
899 {
900 /* Calulate cluster_bits */
901 int cluster_bits;
902 cluster_bits = ffs(cluster_size) - 1;
903 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
904 (1 << cluster_bits) != cluster_size)
905 {
906 error_report(
907 "Cluster size must be a power of two between %d and %dk\n",
908 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
909 return -EINVAL;
910 }
911
912 /*
913 * Open the image file and write a minimal qcow2 header.
914 *
915 * We keep things simple and start with a zero-sized image. We also
916 * do without refcount blocks or a L1 table for now. We'll fix the
917 * inconsistency later.
918 *
919 * We do need a refcount table because growing the refcount table means
920 * allocating two new refcount blocks - the seconds of which would be at
921 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
922 * size for any qcow2 image.
923 */
924 BlockDriverState* bs;
925 QCowHeader header;
926 uint8_t* refcount_table;
927 int ret;
928
929 ret = bdrv_create_file(filename, options);
930 if (ret < 0) {
931 return ret;
932 }
933
934 ret = bdrv_file_open(&bs, filename, BDRV_O_RDWR);
935 if (ret < 0) {
936 return ret;
937 }
938
939 /* Write the header */
940 memset(&header, 0, sizeof(header));
941 header.magic = cpu_to_be32(QCOW_MAGIC);
942 header.version = cpu_to_be32(QCOW_VERSION);
943 header.cluster_bits = cpu_to_be32(cluster_bits);
944 header.size = cpu_to_be64(0);
945 header.l1_table_offset = cpu_to_be64(0);
946 header.l1_size = cpu_to_be32(0);
947 header.refcount_table_offset = cpu_to_be64(cluster_size);
948 header.refcount_table_clusters = cpu_to_be32(1);
949
950 if (flags & BLOCK_FLAG_ENCRYPT) {
951 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
952 } else {
953 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
954 }
955
956 ret = bdrv_pwrite(bs, 0, &header, sizeof(header));
957 if (ret < 0) {
958 goto out;
959 }
960
961 /* Write an empty refcount table */
962 refcount_table = qemu_mallocz(cluster_size);
963 ret = bdrv_pwrite(bs, cluster_size, refcount_table, cluster_size);
964 qemu_free(refcount_table);
965
966 if (ret < 0) {
967 goto out;
968 }
969
970 bdrv_close(bs);
971
972 /*
973 * And now open the image and make it consistent first (i.e. increase the
974 * refcount of the cluster that is occupied by the header and the refcount
975 * table)
976 */
977 BlockDriver* drv = bdrv_find_format("qcow2");
978 assert(drv != NULL);
979 ret = bdrv_open(bs, filename,
980 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, drv);
981 if (ret < 0) {
982 goto out;
983 }
984
985 ret = qcow2_alloc_clusters(bs, 2 * cluster_size);
986 if (ret < 0) {
987 goto out;
988
989 } else if (ret != 0) {
990 error_report("Huh, first cluster in empty image is already in use?");
991 abort();
992 }
993
994 /* Okay, now that we have a valid image, let's give it the right size */
995 ret = bdrv_truncate(bs, total_size * BDRV_SECTOR_SIZE);
996 if (ret < 0) {
997 goto out;
998 }
999
1000 /* Want a backing file? There you go.*/
1001 if (backing_file) {
1002 ret = bdrv_change_backing_file(bs, backing_file, backing_format);
1003 if (ret < 0) {
1004 goto out;
1005 }
1006 }
1007
1008 /* And if we're supposed to preallocate metadata, do that now */
1009 if (prealloc) {
1010 ret = preallocate(bs);
1011 if (ret < 0) {
1012 goto out;
1013 }
1014 }
1015
1016 ret = 0;
1017 out:
1018 bdrv_delete(bs);
1019 return ret;
1020 }
1021
1022 static int qcow2_create(const char *filename, QEMUOptionParameter *options)
1023 {
1024 const char *backing_file = NULL;
1025 const char *backing_fmt = NULL;
1026 uint64_t sectors = 0;
1027 int flags = 0;
1028 size_t cluster_size = 65536;
1029 int prealloc = 0;
1030
1031 /* Read out options */
1032 while (options && options->name) {
1033 if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
1034 sectors = options->value.n / 512;
1035 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
1036 backing_file = options->value.s;
1037 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) {
1038 backing_fmt = options->value.s;
1039 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
1040 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
1041 } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
1042 if (options->value.n) {
1043 cluster_size = options->value.n;
1044 }
1045 } else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) {
1046 if (!options->value.s || !strcmp(options->value.s, "off")) {
1047 prealloc = 0;
1048 } else if (!strcmp(options->value.s, "metadata")) {
1049 prealloc = 1;
1050 } else {
1051 fprintf(stderr, "Invalid preallocation mode: '%s'\n",
1052 options->value.s);
1053 return -EINVAL;
1054 }
1055 }
1056 options++;
1057 }
1058
1059 if (backing_file && prealloc) {
1060 fprintf(stderr, "Backing file and preallocation cannot be used at "
1061 "the same time\n");
1062 return -EINVAL;
1063 }
1064
1065 return qcow2_create2(filename, sectors, backing_file, backing_fmt, flags,
1066 cluster_size, prealloc, options);
1067 }
1068
1069 static int qcow2_make_empty(BlockDriverState *bs)
1070 {
1071 #if 0
1072 /* XXX: not correct */
1073 BDRVQcowState *s = bs->opaque;
1074 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1075 int ret;
1076
1077 memset(s->l1_table, 0, l1_length);
1078 if (bdrv_pwrite(bs->file, s->l1_table_offset, s->l1_table, l1_length) < 0)
1079 return -1;
1080 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
1081 if (ret < 0)
1082 return ret;
1083
1084 l2_cache_reset(bs);
1085 #endif
1086 return 0;
1087 }
1088
1089 static int qcow2_discard(BlockDriverState *bs, int64_t sector_num,
1090 int nb_sectors)
1091 {
1092 return qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS,
1093 nb_sectors);
1094 }
1095
1096 static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
1097 {
1098 BDRVQcowState *s = bs->opaque;
1099 int ret, new_l1_size;
1100
1101 if (offset & 511) {
1102 return -EINVAL;
1103 }
1104
1105 /* cannot proceed if image has snapshots */
1106 if (s->nb_snapshots) {
1107 return -ENOTSUP;
1108 }
1109
1110 /* shrinking is currently not supported */
1111 if (offset < bs->total_sectors * 512) {
1112 return -ENOTSUP;
1113 }
1114
1115 new_l1_size = size_to_l1(s, offset);
1116 ret = qcow2_grow_l1_table(bs, new_l1_size, true);
1117 if (ret < 0) {
1118 return ret;
1119 }
1120
1121 /* write updated header.size */
1122 offset = cpu_to_be64(offset);
1123 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
1124 &offset, sizeof(uint64_t));
1125 if (ret < 0) {
1126 return ret;
1127 }
1128
1129 s->l1_vm_state_index = new_l1_size;
1130 return 0;
1131 }
1132
1133 /* XXX: put compressed sectors first, then all the cluster aligned
1134 tables to avoid losing bytes in alignment */
1135 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
1136 const uint8_t *buf, int nb_sectors)
1137 {
1138 BDRVQcowState *s = bs->opaque;
1139 z_stream strm;
1140 int ret, out_len;
1141 uint8_t *out_buf;
1142 uint64_t cluster_offset;
1143
1144 if (nb_sectors == 0) {
1145 /* align end of file to a sector boundary to ease reading with
1146 sector based I/Os */
1147 cluster_offset = bdrv_getlength(bs->file);
1148 cluster_offset = (cluster_offset + 511) & ~511;
1149 bdrv_truncate(bs->file, cluster_offset);
1150 return 0;
1151 }
1152
1153 if (nb_sectors != s->cluster_sectors)
1154 return -EINVAL;
1155
1156 out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
1157
1158 /* best compression, small window, no zlib header */
1159 memset(&strm, 0, sizeof(strm));
1160 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1161 Z_DEFLATED, -12,
1162 9, Z_DEFAULT_STRATEGY);
1163 if (ret != 0) {
1164 qemu_free(out_buf);
1165 return -1;
1166 }
1167
1168 strm.avail_in = s->cluster_size;
1169 strm.next_in = (uint8_t *)buf;
1170 strm.avail_out = s->cluster_size;
1171 strm.next_out = out_buf;
1172
1173 ret = deflate(&strm, Z_FINISH);
1174 if (ret != Z_STREAM_END && ret != Z_OK) {
1175 qemu_free(out_buf);
1176 deflateEnd(&strm);
1177 return -1;
1178 }
1179 out_len = strm.next_out - out_buf;
1180
1181 deflateEnd(&strm);
1182
1183 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1184 /* could not compress: write normal cluster */
1185 bdrv_write(bs, sector_num, buf, s->cluster_sectors);
1186 } else {
1187 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs,
1188 sector_num << 9, out_len);
1189 if (!cluster_offset)
1190 return -1;
1191 cluster_offset &= s->cluster_offset_mask;
1192 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1193 if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
1194 qemu_free(out_buf);
1195 return -1;
1196 }
1197 }
1198
1199 qemu_free(out_buf);
1200 return 0;
1201 }
1202
1203 static int qcow2_flush(BlockDriverState *bs)
1204 {
1205 BDRVQcowState *s = bs->opaque;
1206 int ret;
1207
1208 ret = qcow2_cache_flush(bs, s->l2_table_cache);
1209 if (ret < 0) {
1210 return ret;
1211 }
1212
1213 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
1214 if (ret < 0) {
1215 return ret;
1216 }
1217
1218 return bdrv_flush(bs->file);
1219 }
1220
1221 static BlockDriverAIOCB *qcow2_aio_flush(BlockDriverState *bs,
1222 BlockDriverCompletionFunc *cb,
1223 void *opaque)
1224 {
1225 BDRVQcowState *s = bs->opaque;
1226 int ret;
1227
1228 ret = qcow2_cache_flush(bs, s->l2_table_cache);
1229 if (ret < 0) {
1230 return NULL;
1231 }
1232
1233 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
1234 if (ret < 0) {
1235 return NULL;
1236 }
1237
1238 return bdrv_aio_flush(bs->file, cb, opaque);
1239 }
1240
1241 static int64_t qcow2_vm_state_offset(BDRVQcowState *s)
1242 {
1243 return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
1244 }
1245
1246 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1247 {
1248 BDRVQcowState *s = bs->opaque;
1249 bdi->cluster_size = s->cluster_size;
1250 bdi->vm_state_offset = qcow2_vm_state_offset(s);
1251 return 0;
1252 }
1253
1254
1255 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result)
1256 {
1257 return qcow2_check_refcounts(bs, result);
1258 }
1259
1260 #if 0
1261 static void dump_refcounts(BlockDriverState *bs)
1262 {
1263 BDRVQcowState *s = bs->opaque;
1264 int64_t nb_clusters, k, k1, size;
1265 int refcount;
1266
1267 size = bdrv_getlength(bs->file);
1268 nb_clusters = size_to_clusters(s, size);
1269 for(k = 0; k < nb_clusters;) {
1270 k1 = k;
1271 refcount = get_refcount(bs, k);
1272 k++;
1273 while (k < nb_clusters && get_refcount(bs, k) == refcount)
1274 k++;
1275 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount,
1276 k - k1);
1277 }
1278 }
1279 #endif
1280
1281 static int qcow2_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
1282 int64_t pos, int size)
1283 {
1284 BDRVQcowState *s = bs->opaque;
1285 int growable = bs->growable;
1286 int ret;
1287
1288 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
1289 bs->growable = 1;
1290 ret = bdrv_pwrite(bs, qcow2_vm_state_offset(s) + pos, buf, size);
1291 bs->growable = growable;
1292
1293 return ret;
1294 }
1295
1296 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf,
1297 int64_t pos, int size)
1298 {
1299 BDRVQcowState *s = bs->opaque;
1300 int growable = bs->growable;
1301 int ret;
1302
1303 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
1304 bs->growable = 1;
1305 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size);
1306 bs->growable = growable;
1307
1308 return ret;
1309 }
1310
1311 static QEMUOptionParameter qcow2_create_options[] = {
1312 {
1313 .name = BLOCK_OPT_SIZE,
1314 .type = OPT_SIZE,
1315 .help = "Virtual disk size"
1316 },
1317 {
1318 .name = BLOCK_OPT_BACKING_FILE,
1319 .type = OPT_STRING,
1320 .help = "File name of a base image"
1321 },
1322 {
1323 .name = BLOCK_OPT_BACKING_FMT,
1324 .type = OPT_STRING,
1325 .help = "Image format of the base image"
1326 },
1327 {
1328 .name = BLOCK_OPT_ENCRYPT,
1329 .type = OPT_FLAG,
1330 .help = "Encrypt the image"
1331 },
1332 {
1333 .name = BLOCK_OPT_CLUSTER_SIZE,
1334 .type = OPT_SIZE,
1335 .help = "qcow2 cluster size"
1336 },
1337 {
1338 .name = BLOCK_OPT_PREALLOC,
1339 .type = OPT_STRING,
1340 .help = "Preallocation mode (allowed values: off, metadata)"
1341 },
1342 { NULL }
1343 };
1344
1345 static BlockDriver bdrv_qcow2 = {
1346 .format_name = "qcow2",
1347 .instance_size = sizeof(BDRVQcowState),
1348 .bdrv_probe = qcow2_probe,
1349 .bdrv_open = qcow2_open,
1350 .bdrv_close = qcow2_close,
1351 .bdrv_create = qcow2_create,
1352 .bdrv_flush = qcow2_flush,
1353 .bdrv_is_allocated = qcow2_is_allocated,
1354 .bdrv_set_key = qcow2_set_key,
1355 .bdrv_make_empty = qcow2_make_empty,
1356
1357 .bdrv_aio_readv = qcow2_aio_readv,
1358 .bdrv_aio_writev = qcow2_aio_writev,
1359 .bdrv_aio_flush = qcow2_aio_flush,
1360
1361 .bdrv_discard = qcow2_discard,
1362 .bdrv_truncate = qcow2_truncate,
1363 .bdrv_write_compressed = qcow2_write_compressed,
1364
1365 .bdrv_snapshot_create = qcow2_snapshot_create,
1366 .bdrv_snapshot_goto = qcow2_snapshot_goto,
1367 .bdrv_snapshot_delete = qcow2_snapshot_delete,
1368 .bdrv_snapshot_list = qcow2_snapshot_list,
1369 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp,
1370 .bdrv_get_info = qcow2_get_info,
1371
1372 .bdrv_save_vmstate = qcow2_save_vmstate,
1373 .bdrv_load_vmstate = qcow2_load_vmstate,
1374
1375 .bdrv_change_backing_file = qcow2_change_backing_file,
1376
1377 .create_options = qcow2_create_options,
1378 .bdrv_check = qcow2_check,
1379 };
1380
1381 static void bdrv_qcow2_init(void)
1382 {
1383 bdrv_register(&bdrv_qcow2);
1384 }
1385
1386 block_init(bdrv_qcow2_init);