2 * Block driver for the QCOW version 2 format
4 * Copyright (c) 2004-2006 Fabrice Bellard
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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
24 #include "qemu-common.h"
25 #include "block_int.h"
29 #include "block/qcow2.h"
30 #include "qemu-error.h"
35 Differences with QCOW:
37 - Support for multiple incremental snapshots.
38 - Memory management by reference counts.
39 - Clusters which have a reference count of one have the bit
40 QCOW_OFLAG_COPIED to optimize write performance.
41 - Size of compressed clusters is stored in sectors to reduce bit usage
42 in the cluster offsets.
43 - Support for storing additional data (such as the VM state) in the
45 - If a backing store is used, the cluster size is not constrained
46 (could be backported to QCOW).
47 - L2 tables have always a size of one cluster.
55 #define QCOW2_EXT_MAGIC_END 0
56 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
57 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
59 static int qcow2_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
61 const QCowHeader
*cow_header
= (const void *)buf
;
63 if (buf_size
>= sizeof(QCowHeader
) &&
64 be32_to_cpu(cow_header
->magic
) == QCOW_MAGIC
&&
65 be32_to_cpu(cow_header
->version
) >= 2)
73 * read qcow2 extension and fill bs
74 * start reading from start_offset
75 * finish reading upon magic of value 0 or when end_offset reached
76 * unknown magic is skipped (future extension this version knows nothing about)
77 * return 0 upon success, non-0 otherwise
79 static int qcow2_read_extensions(BlockDriverState
*bs
, uint64_t start_offset
,
80 uint64_t end_offset
, void **p_feature_table
)
82 BDRVQcowState
*s
= bs
->opaque
;
88 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset
, end_offset
);
90 offset
= start_offset
;
91 while (offset
< end_offset
) {
95 if (offset
> s
->cluster_size
)
96 printf("qcow2_read_extension: suspicious offset %lu\n", offset
);
98 printf("attempting to read extended header in offset %lu\n", offset
);
101 if (bdrv_pread(bs
->file
, offset
, &ext
, sizeof(ext
)) != sizeof(ext
)) {
102 fprintf(stderr
, "qcow2_read_extension: ERROR: "
103 "pread fail from offset %" PRIu64
"\n",
107 be32_to_cpus(&ext
.magic
);
108 be32_to_cpus(&ext
.len
);
109 offset
+= sizeof(ext
);
111 printf("ext.magic = 0x%x\n", ext
.magic
);
113 if (ext
.len
> end_offset
- offset
) {
114 error_report("Header extension too large");
119 case QCOW2_EXT_MAGIC_END
:
122 case QCOW2_EXT_MAGIC_BACKING_FORMAT
:
123 if (ext
.len
>= sizeof(bs
->backing_format
)) {
124 fprintf(stderr
, "ERROR: ext_backing_format: len=%u too large"
126 ext
.len
, sizeof(bs
->backing_format
));
129 if (bdrv_pread(bs
->file
, offset
, bs
->backing_format
,
132 bs
->backing_format
[ext
.len
] = '\0';
134 printf("Qcow2: Got format extension %s\n", bs
->backing_format
);
138 case QCOW2_EXT_MAGIC_FEATURE_TABLE
:
139 if (p_feature_table
!= NULL
) {
140 void* feature_table
= g_malloc0(ext
.len
+ 2 * sizeof(Qcow2Feature
));
141 ret
= bdrv_pread(bs
->file
, offset
, feature_table
, ext
.len
);
146 *p_feature_table
= feature_table
;
151 /* unknown magic - save it in case we need to rewrite the header */
153 Qcow2UnknownHeaderExtension
*uext
;
155 uext
= g_malloc0(sizeof(*uext
) + ext
.len
);
156 uext
->magic
= ext
.magic
;
158 QLIST_INSERT_HEAD(&s
->unknown_header_ext
, uext
, next
);
160 ret
= bdrv_pread(bs
->file
, offset
, uext
->data
, uext
->len
);
168 offset
+= ((ext
.len
+ 7) & ~7);
174 static void cleanup_unknown_header_ext(BlockDriverState
*bs
)
176 BDRVQcowState
*s
= bs
->opaque
;
177 Qcow2UnknownHeaderExtension
*uext
, *next
;
179 QLIST_FOREACH_SAFE(uext
, &s
->unknown_header_ext
, next
, next
) {
180 QLIST_REMOVE(uext
, next
);
185 static void GCC_FMT_ATTR(2, 3) report_unsupported(BlockDriverState
*bs
,
186 const char *fmt
, ...)
192 vsnprintf(msg
, sizeof(msg
), fmt
, ap
);
195 qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE
,
196 bs
->device_name
, "qcow2", msg
);
199 static void report_unsupported_feature(BlockDriverState
*bs
,
200 Qcow2Feature
*table
, uint64_t mask
)
202 while (table
&& table
->name
[0] != '\0') {
203 if (table
->type
== QCOW2_FEAT_TYPE_INCOMPATIBLE
) {
204 if (mask
& (1 << table
->bit
)) {
205 report_unsupported(bs
, "%.46s",table
->name
);
206 mask
&= ~(1 << table
->bit
);
213 report_unsupported(bs
, "Unknown incompatible feature: %" PRIx64
, mask
);
217 static int qcow2_open(BlockDriverState
*bs
, int flags
)
219 BDRVQcowState
*s
= bs
->opaque
;
225 ret
= bdrv_pread(bs
->file
, 0, &header
, sizeof(header
));
229 be32_to_cpus(&header
.magic
);
230 be32_to_cpus(&header
.version
);
231 be64_to_cpus(&header
.backing_file_offset
);
232 be32_to_cpus(&header
.backing_file_size
);
233 be64_to_cpus(&header
.size
);
234 be32_to_cpus(&header
.cluster_bits
);
235 be32_to_cpus(&header
.crypt_method
);
236 be64_to_cpus(&header
.l1_table_offset
);
237 be32_to_cpus(&header
.l1_size
);
238 be64_to_cpus(&header
.refcount_table_offset
);
239 be32_to_cpus(&header
.refcount_table_clusters
);
240 be64_to_cpus(&header
.snapshots_offset
);
241 be32_to_cpus(&header
.nb_snapshots
);
243 if (header
.magic
!= QCOW_MAGIC
) {
247 if (header
.version
< 2 || header
.version
> 3) {
248 report_unsupported(bs
, "QCOW version %d", header
.version
);
253 s
->qcow_version
= header
.version
;
255 /* Initialise version 3 header fields */
256 if (header
.version
== 2) {
257 header
.incompatible_features
= 0;
258 header
.compatible_features
= 0;
259 header
.autoclear_features
= 0;
260 header
.refcount_order
= 4;
261 header
.header_length
= 72;
263 be64_to_cpus(&header
.incompatible_features
);
264 be64_to_cpus(&header
.compatible_features
);
265 be64_to_cpus(&header
.autoclear_features
);
266 be32_to_cpus(&header
.refcount_order
);
267 be32_to_cpus(&header
.header_length
);
270 if (header
.header_length
> sizeof(header
)) {
271 s
->unknown_header_fields_size
= header
.header_length
- sizeof(header
);
272 s
->unknown_header_fields
= g_malloc(s
->unknown_header_fields_size
);
273 ret
= bdrv_pread(bs
->file
, sizeof(header
), s
->unknown_header_fields
,
274 s
->unknown_header_fields_size
);
280 if (header
.backing_file_offset
) {
281 ext_end
= header
.backing_file_offset
;
283 ext_end
= 1 << header
.cluster_bits
;
286 /* Handle feature bits */
287 s
->incompatible_features
= header
.incompatible_features
;
288 s
->compatible_features
= header
.compatible_features
;
289 s
->autoclear_features
= header
.autoclear_features
;
291 if (s
->incompatible_features
!= 0) {
292 void *feature_table
= NULL
;
293 qcow2_read_extensions(bs
, header
.header_length
, ext_end
,
295 report_unsupported_feature(bs
, feature_table
,
296 s
->incompatible_features
);
301 if (!bs
->read_only
&& s
->autoclear_features
!= 0) {
302 s
->autoclear_features
= 0;
303 qcow2_update_header(bs
);
306 /* Check support for various header values */
307 if (header
.refcount_order
!= 4) {
308 report_unsupported(bs
, "%d bit reference counts",
309 1 << header
.refcount_order
);
314 if (header
.cluster_bits
< MIN_CLUSTER_BITS
||
315 header
.cluster_bits
> MAX_CLUSTER_BITS
) {
319 if (header
.crypt_method
> QCOW_CRYPT_AES
) {
323 s
->crypt_method_header
= header
.crypt_method
;
324 if (s
->crypt_method_header
) {
327 s
->cluster_bits
= header
.cluster_bits
;
328 s
->cluster_size
= 1 << s
->cluster_bits
;
329 s
->cluster_sectors
= 1 << (s
->cluster_bits
- 9);
330 s
->l2_bits
= s
->cluster_bits
- 3; /* L2 is always one cluster */
331 s
->l2_size
= 1 << s
->l2_bits
;
332 bs
->total_sectors
= header
.size
/ 512;
333 s
->csize_shift
= (62 - (s
->cluster_bits
- 8));
334 s
->csize_mask
= (1 << (s
->cluster_bits
- 8)) - 1;
335 s
->cluster_offset_mask
= (1LL << s
->csize_shift
) - 1;
336 s
->refcount_table_offset
= header
.refcount_table_offset
;
337 s
->refcount_table_size
=
338 header
.refcount_table_clusters
<< (s
->cluster_bits
- 3);
340 s
->snapshots_offset
= header
.snapshots_offset
;
341 s
->nb_snapshots
= header
.nb_snapshots
;
343 /* read the level 1 table */
344 s
->l1_size
= header
.l1_size
;
345 s
->l1_vm_state_index
= size_to_l1(s
, header
.size
);
346 /* the L1 table must contain at least enough entries to put
348 if (s
->l1_size
< s
->l1_vm_state_index
) {
352 s
->l1_table_offset
= header
.l1_table_offset
;
353 if (s
->l1_size
> 0) {
354 s
->l1_table
= g_malloc0(
355 align_offset(s
->l1_size
* sizeof(uint64_t), 512));
356 ret
= bdrv_pread(bs
->file
, s
->l1_table_offset
, s
->l1_table
,
357 s
->l1_size
* sizeof(uint64_t));
361 for(i
= 0;i
< s
->l1_size
; i
++) {
362 be64_to_cpus(&s
->l1_table
[i
]);
366 /* alloc L2 table/refcount block cache */
367 writethrough
= ((flags
& BDRV_O_CACHE_WB
) == 0);
368 s
->l2_table_cache
= qcow2_cache_create(bs
, L2_CACHE_SIZE
, writethrough
);
369 s
->refcount_block_cache
= qcow2_cache_create(bs
, REFCOUNT_CACHE_SIZE
,
372 s
->cluster_cache
= g_malloc(s
->cluster_size
);
373 /* one more sector for decompressed data alignment */
374 s
->cluster_data
= qemu_blockalign(bs
, QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
376 s
->cluster_cache_offset
= -1;
379 ret
= qcow2_refcount_init(bs
);
384 QLIST_INIT(&s
->cluster_allocs
);
386 /* read qcow2 extensions */
387 if (qcow2_read_extensions(bs
, header
.header_length
, ext_end
, NULL
)) {
392 /* read the backing file name */
393 if (header
.backing_file_offset
!= 0) {
394 len
= header
.backing_file_size
;
398 ret
= bdrv_pread(bs
->file
, header
.backing_file_offset
,
399 bs
->backing_file
, len
);
403 bs
->backing_file
[len
] = '\0';
406 ret
= qcow2_read_snapshots(bs
);
411 /* Initialise locks */
412 qemu_co_mutex_init(&s
->lock
);
416 BdrvCheckResult result
= {0};
417 qcow2_check_refcounts(bs
, &result
);
423 g_free(s
->unknown_header_fields
);
424 cleanup_unknown_header_ext(bs
);
425 qcow2_free_snapshots(bs
);
426 qcow2_refcount_close(bs
);
428 if (s
->l2_table_cache
) {
429 qcow2_cache_destroy(bs
, s
->l2_table_cache
);
431 g_free(s
->cluster_cache
);
432 qemu_vfree(s
->cluster_data
);
436 static int qcow2_set_key(BlockDriverState
*bs
, const char *key
)
438 BDRVQcowState
*s
= bs
->opaque
;
442 memset(keybuf
, 0, 16);
446 /* XXX: we could compress the chars to 7 bits to increase
448 for(i
= 0;i
< len
;i
++) {
451 s
->crypt_method
= s
->crypt_method_header
;
453 if (AES_set_encrypt_key(keybuf
, 128, &s
->aes_encrypt_key
) != 0)
455 if (AES_set_decrypt_key(keybuf
, 128, &s
->aes_decrypt_key
) != 0)
465 AES_encrypt(in
, tmp
, &s
->aes_encrypt_key
);
466 AES_decrypt(tmp
, out
, &s
->aes_decrypt_key
);
467 for(i
= 0; i
< 16; i
++)
468 printf(" %02x", tmp
[i
]);
470 for(i
= 0; i
< 16; i
++)
471 printf(" %02x", out
[i
]);
478 static int coroutine_fn
qcow2_co_is_allocated(BlockDriverState
*bs
,
479 int64_t sector_num
, int nb_sectors
, int *pnum
)
481 BDRVQcowState
*s
= bs
->opaque
;
482 uint64_t cluster_offset
;
486 /* FIXME We can get errors here, but the bdrv_co_is_allocated interface
487 * can't pass them on today */
488 qemu_co_mutex_lock(&s
->lock
);
489 ret
= qcow2_get_cluster_offset(bs
, sector_num
<< 9, pnum
, &cluster_offset
);
490 qemu_co_mutex_unlock(&s
->lock
);
495 return (cluster_offset
!= 0);
498 /* handle reading after the end of the backing file */
499 int qcow2_backing_read1(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
500 int64_t sector_num
, int nb_sectors
)
503 if ((sector_num
+ nb_sectors
) <= bs
->total_sectors
)
505 if (sector_num
>= bs
->total_sectors
)
508 n1
= bs
->total_sectors
- sector_num
;
510 qemu_iovec_memset_skip(qiov
, 0, 512 * (nb_sectors
- n1
), 512 * n1
);
515 static coroutine_fn
int qcow2_co_readv(BlockDriverState
*bs
, int64_t sector_num
,
516 int remaining_sectors
, QEMUIOVector
*qiov
)
518 BDRVQcowState
*s
= bs
->opaque
;
519 int index_in_cluster
, n1
;
521 int cur_nr_sectors
; /* number of sectors in current iteration */
522 uint64_t cluster_offset
= 0;
523 uint64_t bytes_done
= 0;
524 QEMUIOVector hd_qiov
;
525 uint8_t *cluster_data
= NULL
;
527 qemu_iovec_init(&hd_qiov
, qiov
->niov
);
529 qemu_co_mutex_lock(&s
->lock
);
531 while (remaining_sectors
!= 0) {
533 /* prepare next request */
534 cur_nr_sectors
= remaining_sectors
;
535 if (s
->crypt_method
) {
536 cur_nr_sectors
= MIN(cur_nr_sectors
,
537 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
);
540 ret
= qcow2_get_cluster_offset(bs
, sector_num
<< 9,
541 &cur_nr_sectors
, &cluster_offset
);
546 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
548 qemu_iovec_reset(&hd_qiov
);
549 qemu_iovec_copy(&hd_qiov
, qiov
, bytes_done
,
550 cur_nr_sectors
* 512);
553 case QCOW2_CLUSTER_UNALLOCATED
:
555 if (bs
->backing_hd
) {
556 /* read from the base image */
557 n1
= qcow2_backing_read1(bs
->backing_hd
, &hd_qiov
,
558 sector_num
, cur_nr_sectors
);
560 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_BACKING_AIO
);
561 qemu_co_mutex_unlock(&s
->lock
);
562 ret
= bdrv_co_readv(bs
->backing_hd
, sector_num
,
564 qemu_co_mutex_lock(&s
->lock
);
570 /* Note: in this case, no need to wait */
571 qemu_iovec_memset(&hd_qiov
, 0, 512 * cur_nr_sectors
);
575 case QCOW2_CLUSTER_ZERO
:
576 if (s
->qcow_version
< 3) {
580 qemu_iovec_memset(&hd_qiov
, 0, 512 * cur_nr_sectors
);
583 case QCOW2_CLUSTER_COMPRESSED
:
584 /* add AIO support for compressed blocks ? */
585 ret
= qcow2_decompress_cluster(bs
, cluster_offset
);
590 qemu_iovec_from_buffer(&hd_qiov
,
591 s
->cluster_cache
+ index_in_cluster
* 512,
592 512 * cur_nr_sectors
);
595 case QCOW2_CLUSTER_NORMAL
:
596 if ((cluster_offset
& 511) != 0) {
601 if (s
->crypt_method
) {
603 * For encrypted images, read everything into a temporary
604 * contiguous buffer on which the AES functions can work.
608 qemu_blockalign(bs
, QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
611 assert(cur_nr_sectors
<=
612 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
);
613 qemu_iovec_reset(&hd_qiov
);
614 qemu_iovec_add(&hd_qiov
, cluster_data
,
615 512 * cur_nr_sectors
);
618 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_AIO
);
619 qemu_co_mutex_unlock(&s
->lock
);
620 ret
= bdrv_co_readv(bs
->file
,
621 (cluster_offset
>> 9) + index_in_cluster
,
622 cur_nr_sectors
, &hd_qiov
);
623 qemu_co_mutex_lock(&s
->lock
);
627 if (s
->crypt_method
) {
628 qcow2_encrypt_sectors(s
, sector_num
, cluster_data
,
629 cluster_data
, cur_nr_sectors
, 0, &s
->aes_decrypt_key
);
630 qemu_iovec_reset(&hd_qiov
);
631 qemu_iovec_copy(&hd_qiov
, qiov
, bytes_done
,
632 cur_nr_sectors
* 512);
633 qemu_iovec_from_buffer(&hd_qiov
, cluster_data
,
634 512 * cur_nr_sectors
);
639 g_assert_not_reached();
644 remaining_sectors
-= cur_nr_sectors
;
645 sector_num
+= cur_nr_sectors
;
646 bytes_done
+= cur_nr_sectors
* 512;
651 qemu_co_mutex_unlock(&s
->lock
);
653 qemu_iovec_destroy(&hd_qiov
);
654 qemu_vfree(cluster_data
);
659 static void run_dependent_requests(BDRVQcowState
*s
, QCowL2Meta
*m
)
661 /* Take the request off the list of running requests */
662 if (m
->nb_clusters
!= 0) {
663 QLIST_REMOVE(m
, next_in_flight
);
666 /* Restart all dependent requests */
667 if (!qemu_co_queue_empty(&m
->dependent_requests
)) {
668 qemu_co_mutex_unlock(&s
->lock
);
669 qemu_co_queue_restart_all(&m
->dependent_requests
);
670 qemu_co_mutex_lock(&s
->lock
);
674 static coroutine_fn
int qcow2_co_writev(BlockDriverState
*bs
,
676 int remaining_sectors
,
679 BDRVQcowState
*s
= bs
->opaque
;
680 int index_in_cluster
;
683 int cur_nr_sectors
; /* number of sectors in current iteration */
684 uint64_t cluster_offset
;
685 QEMUIOVector hd_qiov
;
686 uint64_t bytes_done
= 0;
687 uint8_t *cluster_data
= NULL
;
688 QCowL2Meta l2meta
= {
692 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num
,
695 qemu_co_queue_init(&l2meta
.dependent_requests
);
697 qemu_iovec_init(&hd_qiov
, qiov
->niov
);
699 s
->cluster_cache_offset
= -1; /* disable compressed cache */
701 qemu_co_mutex_lock(&s
->lock
);
703 while (remaining_sectors
!= 0) {
705 trace_qcow2_writev_start_part(qemu_coroutine_self());
706 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
707 n_end
= index_in_cluster
+ remaining_sectors
;
708 if (s
->crypt_method
&&
709 n_end
> QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
) {
710 n_end
= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
;
713 ret
= qcow2_alloc_cluster_offset(bs
, sector_num
<< 9,
714 index_in_cluster
, n_end
, &cur_nr_sectors
, &l2meta
);
719 cluster_offset
= l2meta
.cluster_offset
;
720 assert((cluster_offset
& 511) == 0);
722 qemu_iovec_reset(&hd_qiov
);
723 qemu_iovec_copy(&hd_qiov
, qiov
, bytes_done
,
724 cur_nr_sectors
* 512);
726 if (s
->crypt_method
) {
728 cluster_data
= qemu_blockalign(bs
, QCOW_MAX_CRYPT_CLUSTERS
*
732 assert(hd_qiov
.size
<=
733 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
734 qemu_iovec_to_buffer(&hd_qiov
, cluster_data
);
736 qcow2_encrypt_sectors(s
, sector_num
, cluster_data
,
737 cluster_data
, cur_nr_sectors
, 1, &s
->aes_encrypt_key
);
739 qemu_iovec_reset(&hd_qiov
);
740 qemu_iovec_add(&hd_qiov
, cluster_data
,
741 cur_nr_sectors
* 512);
744 BLKDBG_EVENT(bs
->file
, BLKDBG_WRITE_AIO
);
745 qemu_co_mutex_unlock(&s
->lock
);
746 trace_qcow2_writev_data(qemu_coroutine_self(),
747 (cluster_offset
>> 9) + index_in_cluster
);
748 ret
= bdrv_co_writev(bs
->file
,
749 (cluster_offset
>> 9) + index_in_cluster
,
750 cur_nr_sectors
, &hd_qiov
);
751 qemu_co_mutex_lock(&s
->lock
);
756 ret
= qcow2_alloc_cluster_link_l2(bs
, &l2meta
);
761 run_dependent_requests(s
, &l2meta
);
763 remaining_sectors
-= cur_nr_sectors
;
764 sector_num
+= cur_nr_sectors
;
765 bytes_done
+= cur_nr_sectors
* 512;
766 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors
);
771 run_dependent_requests(s
, &l2meta
);
773 qemu_co_mutex_unlock(&s
->lock
);
775 qemu_iovec_destroy(&hd_qiov
);
776 qemu_vfree(cluster_data
);
777 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret
);
782 static void qcow2_close(BlockDriverState
*bs
)
784 BDRVQcowState
*s
= bs
->opaque
;
787 qcow2_cache_flush(bs
, s
->l2_table_cache
);
788 qcow2_cache_flush(bs
, s
->refcount_block_cache
);
790 qcow2_cache_destroy(bs
, s
->l2_table_cache
);
791 qcow2_cache_destroy(bs
, s
->refcount_block_cache
);
793 g_free(s
->unknown_header_fields
);
794 cleanup_unknown_header_ext(bs
);
796 g_free(s
->cluster_cache
);
797 qemu_vfree(s
->cluster_data
);
798 qcow2_refcount_close(bs
);
799 qcow2_free_snapshots(bs
);
802 static void qcow2_invalidate_cache(BlockDriverState
*bs
)
804 BDRVQcowState
*s
= bs
->opaque
;
805 int flags
= s
->flags
;
806 AES_KEY aes_encrypt_key
;
807 AES_KEY aes_decrypt_key
;
808 uint32_t crypt_method
= 0;
811 * Backing files are read-only which makes all of their metadata immutable,
812 * that means we don't have to worry about reopening them here.
815 if (s
->crypt_method
) {
816 crypt_method
= s
->crypt_method
;
817 memcpy(&aes_encrypt_key
, &s
->aes_encrypt_key
, sizeof(aes_encrypt_key
));
818 memcpy(&aes_decrypt_key
, &s
->aes_decrypt_key
, sizeof(aes_decrypt_key
));
823 memset(s
, 0, sizeof(BDRVQcowState
));
824 qcow2_open(bs
, flags
);
827 s
->crypt_method
= crypt_method
;
828 memcpy(&s
->aes_encrypt_key
, &aes_encrypt_key
, sizeof(aes_encrypt_key
));
829 memcpy(&s
->aes_decrypt_key
, &aes_decrypt_key
, sizeof(aes_decrypt_key
));
833 static size_t header_ext_add(char *buf
, uint32_t magic
, const void *s
,
834 size_t len
, size_t buflen
)
836 QCowExtension
*ext_backing_fmt
= (QCowExtension
*) buf
;
837 size_t ext_len
= sizeof(QCowExtension
) + ((len
+ 7) & ~7);
839 if (buflen
< ext_len
) {
843 *ext_backing_fmt
= (QCowExtension
) {
844 .magic
= cpu_to_be32(magic
),
845 .len
= cpu_to_be32(len
),
847 memcpy(buf
+ sizeof(QCowExtension
), s
, len
);
853 * Updates the qcow2 header, including the variable length parts of it, i.e.
854 * the backing file name and all extensions. qcow2 was not designed to allow
855 * such changes, so if we run out of space (we can only use the first cluster)
856 * this function may fail.
858 * Returns 0 on success, -errno in error cases.
860 int qcow2_update_header(BlockDriverState
*bs
)
862 BDRVQcowState
*s
= bs
->opaque
;
865 size_t buflen
= s
->cluster_size
;
868 uint32_t refcount_table_clusters
;
869 size_t header_length
;
870 Qcow2UnknownHeaderExtension
*uext
;
872 buf
= qemu_blockalign(bs
, buflen
);
874 /* Header structure */
875 header
= (QCowHeader
*) buf
;
877 if (buflen
< sizeof(*header
)) {
882 header_length
= sizeof(*header
) + s
->unknown_header_fields_size
;
883 total_size
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
884 refcount_table_clusters
= s
->refcount_table_size
>> (s
->cluster_bits
- 3);
886 *header
= (QCowHeader
) {
887 /* Version 2 fields */
888 .magic
= cpu_to_be32(QCOW_MAGIC
),
889 .version
= cpu_to_be32(s
->qcow_version
),
890 .backing_file_offset
= 0,
891 .backing_file_size
= 0,
892 .cluster_bits
= cpu_to_be32(s
->cluster_bits
),
893 .size
= cpu_to_be64(total_size
),
894 .crypt_method
= cpu_to_be32(s
->crypt_method_header
),
895 .l1_size
= cpu_to_be32(s
->l1_size
),
896 .l1_table_offset
= cpu_to_be64(s
->l1_table_offset
),
897 .refcount_table_offset
= cpu_to_be64(s
->refcount_table_offset
),
898 .refcount_table_clusters
= cpu_to_be32(refcount_table_clusters
),
899 .nb_snapshots
= cpu_to_be32(s
->nb_snapshots
),
900 .snapshots_offset
= cpu_to_be64(s
->snapshots_offset
),
902 /* Version 3 fields */
903 .incompatible_features
= cpu_to_be64(s
->incompatible_features
),
904 .compatible_features
= cpu_to_be64(s
->compatible_features
),
905 .autoclear_features
= cpu_to_be64(s
->autoclear_features
),
906 .refcount_order
= cpu_to_be32(3 + REFCOUNT_SHIFT
),
907 .header_length
= cpu_to_be32(header_length
),
910 /* For older versions, write a shorter header */
911 switch (s
->qcow_version
) {
913 ret
= offsetof(QCowHeader
, incompatible_features
);
916 ret
= sizeof(*header
);
924 memset(buf
, 0, buflen
);
926 /* Preserve any unknown field in the header */
927 if (s
->unknown_header_fields_size
) {
928 if (buflen
< s
->unknown_header_fields_size
) {
933 memcpy(buf
, s
->unknown_header_fields
, s
->unknown_header_fields_size
);
934 buf
+= s
->unknown_header_fields_size
;
935 buflen
-= s
->unknown_header_fields_size
;
938 /* Backing file format header extension */
939 if (*bs
->backing_format
) {
940 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_BACKING_FORMAT
,
941 bs
->backing_format
, strlen(bs
->backing_format
),
952 Qcow2Feature features
[] = {
953 /* no feature defined yet */
956 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_FEATURE_TABLE
,
957 features
, sizeof(features
), buflen
);
964 /* Keep unknown header extensions */
965 QLIST_FOREACH(uext
, &s
->unknown_header_ext
, next
) {
966 ret
= header_ext_add(buf
, uext
->magic
, uext
->data
, uext
->len
, buflen
);
975 /* End of header extensions */
976 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_END
, NULL
, 0, buflen
);
984 /* Backing file name */
985 if (*bs
->backing_file
) {
986 size_t backing_file_len
= strlen(bs
->backing_file
);
988 if (buflen
< backing_file_len
) {
993 strncpy(buf
, bs
->backing_file
, buflen
);
995 header
->backing_file_offset
= cpu_to_be64(buf
- ((char*) header
));
996 header
->backing_file_size
= cpu_to_be32(backing_file_len
);
999 /* Write the new header */
1000 ret
= bdrv_pwrite(bs
->file
, 0, header
, s
->cluster_size
);
1011 static int qcow2_change_backing_file(BlockDriverState
*bs
,
1012 const char *backing_file
, const char *backing_fmt
)
1014 /* Backing file format doesn't make sense without a backing file */
1015 if (backing_fmt
&& !backing_file
) {
1019 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
1020 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
1022 return qcow2_update_header(bs
);
1025 static int preallocate(BlockDriverState
*bs
)
1027 uint64_t nb_sectors
;
1033 nb_sectors
= bdrv_getlength(bs
) >> 9;
1035 qemu_co_queue_init(&meta
.dependent_requests
);
1036 meta
.cluster_offset
= 0;
1038 while (nb_sectors
) {
1039 num
= MIN(nb_sectors
, INT_MAX
>> 9);
1040 ret
= qcow2_alloc_cluster_offset(bs
, offset
, 0, num
, &num
, &meta
);
1045 ret
= qcow2_alloc_cluster_link_l2(bs
, &meta
);
1047 qcow2_free_any_clusters(bs
, meta
.cluster_offset
, meta
.nb_clusters
);
1051 /* There are no dependent requests, but we need to remove our request
1052 * from the list of in-flight requests */
1053 run_dependent_requests(bs
->opaque
, &meta
);
1055 /* TODO Preallocate data if requested */
1062 * It is expected that the image file is large enough to actually contain
1063 * all of the allocated clusters (otherwise we get failing reads after
1064 * EOF). Extend the image to the last allocated sector.
1066 if (meta
.cluster_offset
!= 0) {
1068 memset(buf
, 0, 512);
1069 ret
= bdrv_write(bs
->file
, (meta
.cluster_offset
>> 9) + num
- 1, buf
, 1);
1078 static int qcow2_create2(const char *filename
, int64_t total_size
,
1079 const char *backing_file
, const char *backing_format
,
1080 int flags
, size_t cluster_size
, int prealloc
,
1081 QEMUOptionParameter
*options
, int version
)
1083 /* Calculate cluster_bits */
1085 cluster_bits
= ffs(cluster_size
) - 1;
1086 if (cluster_bits
< MIN_CLUSTER_BITS
|| cluster_bits
> MAX_CLUSTER_BITS
||
1087 (1 << cluster_bits
) != cluster_size
)
1090 "Cluster size must be a power of two between %d and %dk",
1091 1 << MIN_CLUSTER_BITS
, 1 << (MAX_CLUSTER_BITS
- 10));
1096 * Open the image file and write a minimal qcow2 header.
1098 * We keep things simple and start with a zero-sized image. We also
1099 * do without refcount blocks or a L1 table for now. We'll fix the
1100 * inconsistency later.
1102 * We do need a refcount table because growing the refcount table means
1103 * allocating two new refcount blocks - the seconds of which would be at
1104 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
1105 * size for any qcow2 image.
1107 BlockDriverState
* bs
;
1109 uint8_t* refcount_table
;
1112 ret
= bdrv_create_file(filename
, options
);
1117 ret
= bdrv_file_open(&bs
, filename
, BDRV_O_RDWR
);
1122 /* Write the header */
1123 memset(&header
, 0, sizeof(header
));
1124 header
.magic
= cpu_to_be32(QCOW_MAGIC
);
1125 header
.version
= cpu_to_be32(version
);
1126 header
.cluster_bits
= cpu_to_be32(cluster_bits
);
1127 header
.size
= cpu_to_be64(0);
1128 header
.l1_table_offset
= cpu_to_be64(0);
1129 header
.l1_size
= cpu_to_be32(0);
1130 header
.refcount_table_offset
= cpu_to_be64(cluster_size
);
1131 header
.refcount_table_clusters
= cpu_to_be32(1);
1132 header
.refcount_order
= cpu_to_be32(3 + REFCOUNT_SHIFT
);
1133 header
.header_length
= cpu_to_be32(sizeof(header
));
1135 if (flags
& BLOCK_FLAG_ENCRYPT
) {
1136 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_AES
);
1138 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
1141 ret
= bdrv_pwrite(bs
, 0, &header
, sizeof(header
));
1146 /* Write an empty refcount table */
1147 refcount_table
= g_malloc0(cluster_size
);
1148 ret
= bdrv_pwrite(bs
, cluster_size
, refcount_table
, cluster_size
);
1149 g_free(refcount_table
);
1158 * And now open the image and make it consistent first (i.e. increase the
1159 * refcount of the cluster that is occupied by the header and the refcount
1162 BlockDriver
* drv
= bdrv_find_format("qcow2");
1163 assert(drv
!= NULL
);
1164 ret
= bdrv_open(bs
, filename
,
1165 BDRV_O_RDWR
| BDRV_O_CACHE_WB
| BDRV_O_NO_FLUSH
, drv
);
1170 ret
= qcow2_alloc_clusters(bs
, 2 * cluster_size
);
1174 } else if (ret
!= 0) {
1175 error_report("Huh, first cluster in empty image is already in use?");
1179 /* Okay, now that we have a valid image, let's give it the right size */
1180 ret
= bdrv_truncate(bs
, total_size
* BDRV_SECTOR_SIZE
);
1185 /* Want a backing file? There you go.*/
1187 ret
= bdrv_change_backing_file(bs
, backing_file
, backing_format
);
1193 /* And if we're supposed to preallocate metadata, do that now */
1195 ret
= preallocate(bs
);
1207 static int qcow2_create(const char *filename
, QEMUOptionParameter
*options
)
1209 const char *backing_file
= NULL
;
1210 const char *backing_fmt
= NULL
;
1211 uint64_t sectors
= 0;
1213 size_t cluster_size
= DEFAULT_CLUSTER_SIZE
;
1217 /* Read out options */
1218 while (options
&& options
->name
) {
1219 if (!strcmp(options
->name
, BLOCK_OPT_SIZE
)) {
1220 sectors
= options
->value
.n
/ 512;
1221 } else if (!strcmp(options
->name
, BLOCK_OPT_BACKING_FILE
)) {
1222 backing_file
= options
->value
.s
;
1223 } else if (!strcmp(options
->name
, BLOCK_OPT_BACKING_FMT
)) {
1224 backing_fmt
= options
->value
.s
;
1225 } else if (!strcmp(options
->name
, BLOCK_OPT_ENCRYPT
)) {
1226 flags
|= options
->value
.n
? BLOCK_FLAG_ENCRYPT
: 0;
1227 } else if (!strcmp(options
->name
, BLOCK_OPT_CLUSTER_SIZE
)) {
1228 if (options
->value
.n
) {
1229 cluster_size
= options
->value
.n
;
1231 } else if (!strcmp(options
->name
, BLOCK_OPT_PREALLOC
)) {
1232 if (!options
->value
.s
|| !strcmp(options
->value
.s
, "off")) {
1234 } else if (!strcmp(options
->value
.s
, "metadata")) {
1237 fprintf(stderr
, "Invalid preallocation mode: '%s'\n",
1241 } else if (!strcmp(options
->name
, BLOCK_OPT_COMPAT_LEVEL
)) {
1242 if (!options
->value
.s
|| !strcmp(options
->value
.s
, "0.10")) {
1244 } else if (!strcmp(options
->value
.s
, "1.1")) {
1247 fprintf(stderr
, "Invalid compatibility level: '%s'\n",
1255 if (backing_file
&& prealloc
) {
1256 fprintf(stderr
, "Backing file and preallocation cannot be used at "
1261 return qcow2_create2(filename
, sectors
, backing_file
, backing_fmt
, flags
,
1262 cluster_size
, prealloc
, options
, version
);
1265 static int qcow2_make_empty(BlockDriverState
*bs
)
1268 /* XXX: not correct */
1269 BDRVQcowState
*s
= bs
->opaque
;
1270 uint32_t l1_length
= s
->l1_size
* sizeof(uint64_t);
1273 memset(s
->l1_table
, 0, l1_length
);
1274 if (bdrv_pwrite(bs
->file
, s
->l1_table_offset
, s
->l1_table
, l1_length
) < 0)
1276 ret
= bdrv_truncate(bs
->file
, s
->l1_table_offset
+ l1_length
);
1285 static coroutine_fn
int qcow2_co_write_zeroes(BlockDriverState
*bs
,
1286 int64_t sector_num
, int nb_sectors
)
1289 BDRVQcowState
*s
= bs
->opaque
;
1291 /* Emulate misaligned zero writes */
1292 if (sector_num
% s
->cluster_sectors
|| nb_sectors
% s
->cluster_sectors
) {
1296 /* Whatever is left can use real zero clusters */
1297 qemu_co_mutex_lock(&s
->lock
);
1298 ret
= qcow2_zero_clusters(bs
, sector_num
<< BDRV_SECTOR_BITS
,
1300 qemu_co_mutex_unlock(&s
->lock
);
1305 static coroutine_fn
int qcow2_co_discard(BlockDriverState
*bs
,
1306 int64_t sector_num
, int nb_sectors
)
1309 BDRVQcowState
*s
= bs
->opaque
;
1311 qemu_co_mutex_lock(&s
->lock
);
1312 ret
= qcow2_discard_clusters(bs
, sector_num
<< BDRV_SECTOR_BITS
,
1314 qemu_co_mutex_unlock(&s
->lock
);
1318 static int qcow2_truncate(BlockDriverState
*bs
, int64_t offset
)
1320 BDRVQcowState
*s
= bs
->opaque
;
1321 int ret
, new_l1_size
;
1324 error_report("The new size must be a multiple of 512");
1328 /* cannot proceed if image has snapshots */
1329 if (s
->nb_snapshots
) {
1330 error_report("Can't resize an image which has snapshots");
1334 /* shrinking is currently not supported */
1335 if (offset
< bs
->total_sectors
* 512) {
1336 error_report("qcow2 doesn't support shrinking images yet");
1340 new_l1_size
= size_to_l1(s
, offset
);
1341 ret
= qcow2_grow_l1_table(bs
, new_l1_size
, true);
1346 /* write updated header.size */
1347 offset
= cpu_to_be64(offset
);
1348 ret
= bdrv_pwrite_sync(bs
->file
, offsetof(QCowHeader
, size
),
1349 &offset
, sizeof(uint64_t));
1354 s
->l1_vm_state_index
= new_l1_size
;
1358 /* XXX: put compressed sectors first, then all the cluster aligned
1359 tables to avoid losing bytes in alignment */
1360 static int qcow2_write_compressed(BlockDriverState
*bs
, int64_t sector_num
,
1361 const uint8_t *buf
, int nb_sectors
)
1363 BDRVQcowState
*s
= bs
->opaque
;
1367 uint64_t cluster_offset
;
1369 if (nb_sectors
== 0) {
1370 /* align end of file to a sector boundary to ease reading with
1371 sector based I/Os */
1372 cluster_offset
= bdrv_getlength(bs
->file
);
1373 cluster_offset
= (cluster_offset
+ 511) & ~511;
1374 bdrv_truncate(bs
->file
, cluster_offset
);
1378 if (nb_sectors
!= s
->cluster_sectors
)
1381 out_buf
= g_malloc(s
->cluster_size
+ (s
->cluster_size
/ 1000) + 128);
1383 /* best compression, small window, no zlib header */
1384 memset(&strm
, 0, sizeof(strm
));
1385 ret
= deflateInit2(&strm
, Z_DEFAULT_COMPRESSION
,
1387 9, Z_DEFAULT_STRATEGY
);
1393 strm
.avail_in
= s
->cluster_size
;
1394 strm
.next_in
= (uint8_t *)buf
;
1395 strm
.avail_out
= s
->cluster_size
;
1396 strm
.next_out
= out_buf
;
1398 ret
= deflate(&strm
, Z_FINISH
);
1399 if (ret
!= Z_STREAM_END
&& ret
!= Z_OK
) {
1404 out_len
= strm
.next_out
- out_buf
;
1408 if (ret
!= Z_STREAM_END
|| out_len
>= s
->cluster_size
) {
1409 /* could not compress: write normal cluster */
1410 ret
= bdrv_write(bs
, sector_num
, buf
, s
->cluster_sectors
);
1415 cluster_offset
= qcow2_alloc_compressed_cluster_offset(bs
,
1416 sector_num
<< 9, out_len
);
1417 if (!cluster_offset
) {
1421 cluster_offset
&= s
->cluster_offset_mask
;
1422 BLKDBG_EVENT(bs
->file
, BLKDBG_WRITE_COMPRESSED
);
1423 ret
= bdrv_pwrite(bs
->file
, cluster_offset
, out_buf
, out_len
);
1435 static coroutine_fn
int qcow2_co_flush_to_os(BlockDriverState
*bs
)
1437 BDRVQcowState
*s
= bs
->opaque
;
1440 qemu_co_mutex_lock(&s
->lock
);
1441 ret
= qcow2_cache_flush(bs
, s
->l2_table_cache
);
1443 qemu_co_mutex_unlock(&s
->lock
);
1447 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
1449 qemu_co_mutex_unlock(&s
->lock
);
1452 qemu_co_mutex_unlock(&s
->lock
);
1457 static int64_t qcow2_vm_state_offset(BDRVQcowState
*s
)
1459 return (int64_t)s
->l1_vm_state_index
<< (s
->cluster_bits
+ s
->l2_bits
);
1462 static int qcow2_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
1464 BDRVQcowState
*s
= bs
->opaque
;
1465 bdi
->cluster_size
= s
->cluster_size
;
1466 bdi
->vm_state_offset
= qcow2_vm_state_offset(s
);
1471 static int qcow2_check(BlockDriverState
*bs
, BdrvCheckResult
*result
)
1473 return qcow2_check_refcounts(bs
, result
);
1477 static void dump_refcounts(BlockDriverState
*bs
)
1479 BDRVQcowState
*s
= bs
->opaque
;
1480 int64_t nb_clusters
, k
, k1
, size
;
1483 size
= bdrv_getlength(bs
->file
);
1484 nb_clusters
= size_to_clusters(s
, size
);
1485 for(k
= 0; k
< nb_clusters
;) {
1487 refcount
= get_refcount(bs
, k
);
1489 while (k
< nb_clusters
&& get_refcount(bs
, k
) == refcount
)
1491 printf("%" PRId64
": refcount=%d nb=%" PRId64
"\n", k
, refcount
,
1497 static int qcow2_save_vmstate(BlockDriverState
*bs
, const uint8_t *buf
,
1498 int64_t pos
, int size
)
1500 BDRVQcowState
*s
= bs
->opaque
;
1501 int growable
= bs
->growable
;
1504 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_SAVE
);
1506 ret
= bdrv_pwrite(bs
, qcow2_vm_state_offset(s
) + pos
, buf
, size
);
1507 bs
->growable
= growable
;
1512 static int qcow2_load_vmstate(BlockDriverState
*bs
, uint8_t *buf
,
1513 int64_t pos
, int size
)
1515 BDRVQcowState
*s
= bs
->opaque
;
1516 int growable
= bs
->growable
;
1519 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_LOAD
);
1521 ret
= bdrv_pread(bs
, qcow2_vm_state_offset(s
) + pos
, buf
, size
);
1522 bs
->growable
= growable
;
1527 static QEMUOptionParameter qcow2_create_options
[] = {
1529 .name
= BLOCK_OPT_SIZE
,
1531 .help
= "Virtual disk size"
1534 .name
= BLOCK_OPT_COMPAT_LEVEL
,
1536 .help
= "Compatibility level (0.10 or 1.1)"
1539 .name
= BLOCK_OPT_BACKING_FILE
,
1541 .help
= "File name of a base image"
1544 .name
= BLOCK_OPT_BACKING_FMT
,
1546 .help
= "Image format of the base image"
1549 .name
= BLOCK_OPT_ENCRYPT
,
1551 .help
= "Encrypt the image"
1554 .name
= BLOCK_OPT_CLUSTER_SIZE
,
1556 .help
= "qcow2 cluster size",
1557 .value
= { .n
= DEFAULT_CLUSTER_SIZE
},
1560 .name
= BLOCK_OPT_PREALLOC
,
1562 .help
= "Preallocation mode (allowed values: off, metadata)"
1567 static BlockDriver bdrv_qcow2
= {
1568 .format_name
= "qcow2",
1569 .instance_size
= sizeof(BDRVQcowState
),
1570 .bdrv_probe
= qcow2_probe
,
1571 .bdrv_open
= qcow2_open
,
1572 .bdrv_close
= qcow2_close
,
1573 .bdrv_create
= qcow2_create
,
1574 .bdrv_co_is_allocated
= qcow2_co_is_allocated
,
1575 .bdrv_set_key
= qcow2_set_key
,
1576 .bdrv_make_empty
= qcow2_make_empty
,
1578 .bdrv_co_readv
= qcow2_co_readv
,
1579 .bdrv_co_writev
= qcow2_co_writev
,
1580 .bdrv_co_flush_to_os
= qcow2_co_flush_to_os
,
1582 .bdrv_co_write_zeroes
= qcow2_co_write_zeroes
,
1583 .bdrv_co_discard
= qcow2_co_discard
,
1584 .bdrv_truncate
= qcow2_truncate
,
1585 .bdrv_write_compressed
= qcow2_write_compressed
,
1587 .bdrv_snapshot_create
= qcow2_snapshot_create
,
1588 .bdrv_snapshot_goto
= qcow2_snapshot_goto
,
1589 .bdrv_snapshot_delete
= qcow2_snapshot_delete
,
1590 .bdrv_snapshot_list
= qcow2_snapshot_list
,
1591 .bdrv_snapshot_load_tmp
= qcow2_snapshot_load_tmp
,
1592 .bdrv_get_info
= qcow2_get_info
,
1594 .bdrv_save_vmstate
= qcow2_save_vmstate
,
1595 .bdrv_load_vmstate
= qcow2_load_vmstate
,
1597 .bdrv_change_backing_file
= qcow2_change_backing_file
,
1599 .bdrv_invalidate_cache
= qcow2_invalidate_cache
,
1601 .create_options
= qcow2_create_options
,
1602 .bdrv_check
= qcow2_check
,
1605 static void bdrv_qcow2_init(void)
1607 bdrv_register(&bdrv_qcow2
);
1610 block_init(bdrv_qcow2_init
);