2 * Block driver for the QCOW 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
25 #include "qemu/osdep.h"
26 #include "qapi/error.h"
27 #include "qemu/error-report.h"
28 #include "block/block_int.h"
29 #include "block/qdict.h"
30 #include "sysemu/block-backend.h"
31 #include "qemu/module.h"
32 #include "qemu/option.h"
33 #include "qemu/bswap.h"
34 #include "qemu/cutils.h"
35 #include "qemu/memalign.h"
37 #include "qapi/qmp/qdict.h"
38 #include "qapi/qmp/qstring.h"
39 #include "qapi/qobject-input-visitor.h"
40 #include "qapi/qapi-visit-block-core.h"
41 #include "crypto/block.h"
42 #include "migration/blocker.h"
45 /**************************************************************/
46 /* QEMU COW block driver with compression and encryption support */
48 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
49 #define QCOW_VERSION 1
51 #define QCOW_CRYPT_NONE 0
52 #define QCOW_CRYPT_AES 1
54 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
56 typedef struct QCowHeader
{
59 uint64_t backing_file_offset
;
60 uint32_t backing_file_size
;
62 uint64_t size
; /* in bytes */
66 uint32_t crypt_method
;
67 uint64_t l1_table_offset
;
68 } QEMU_PACKED QCowHeader
;
70 #define L2_CACHE_SIZE 16
72 typedef struct BDRVQcowState
{
78 uint64_t cluster_offset_mask
;
79 uint64_t l1_table_offset
;
82 uint64_t l2_cache_offsets
[L2_CACHE_SIZE
];
83 uint32_t l2_cache_counts
[L2_CACHE_SIZE
];
84 uint8_t *cluster_cache
;
85 uint8_t *cluster_data
;
86 uint64_t cluster_cache_offset
;
87 QCryptoBlock
*crypto
; /* Disk encryption format driver */
88 uint32_t crypt_method_header
;
90 Error
*migration_blocker
;
93 static QemuOptsList qcow_create_opts
;
95 static int coroutine_fn GRAPH_RDLOCK
96 decompress_cluster(BlockDriverState
*bs
, uint64_t cluster_offset
);
98 static int qcow_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
100 const QCowHeader
*cow_header
= (const void *)buf
;
102 if (buf_size
>= sizeof(QCowHeader
) &&
103 be32_to_cpu(cow_header
->magic
) == QCOW_MAGIC
&&
104 be32_to_cpu(cow_header
->version
) == QCOW_VERSION
)
110 static int qcow_open(BlockDriverState
*bs
, QDict
*options
, int flags
,
113 BDRVQcowState
*s
= bs
->opaque
;
114 unsigned int len
, i
, shift
;
117 QCryptoBlockOpenOptions
*crypto_opts
= NULL
;
118 unsigned int cflags
= 0;
119 QDict
*encryptopts
= NULL
;
120 const char *encryptfmt
;
122 qdict_extract_subqdict(options
, &encryptopts
, "encrypt.");
123 encryptfmt
= qdict_get_try_str(encryptopts
, "format");
125 ret
= bdrv_open_file_child(NULL
, options
, "file", bs
, errp
);
130 ret
= bdrv_pread(bs
->file
, 0, sizeof(header
), &header
, 0);
134 header
.magic
= be32_to_cpu(header
.magic
);
135 header
.version
= be32_to_cpu(header
.version
);
136 header
.backing_file_offset
= be64_to_cpu(header
.backing_file_offset
);
137 header
.backing_file_size
= be32_to_cpu(header
.backing_file_size
);
138 header
.mtime
= be32_to_cpu(header
.mtime
);
139 header
.size
= be64_to_cpu(header
.size
);
140 header
.crypt_method
= be32_to_cpu(header
.crypt_method
);
141 header
.l1_table_offset
= be64_to_cpu(header
.l1_table_offset
);
143 if (header
.magic
!= QCOW_MAGIC
) {
144 error_setg(errp
, "Image not in qcow format");
148 if (header
.version
!= QCOW_VERSION
) {
149 error_setg(errp
, "qcow (v%d) does not support qcow version %" PRIu32
,
150 QCOW_VERSION
, header
.version
);
151 if (header
.version
== 2 || header
.version
== 3) {
152 error_append_hint(errp
, "Try the 'qcow2' driver instead.\n");
159 if (header
.size
<= 1) {
160 error_setg(errp
, "Image size is too small (must be at least 2 bytes)");
164 if (header
.cluster_bits
< 9 || header
.cluster_bits
> 16) {
165 error_setg(errp
, "Cluster size must be between 512 and 64k");
170 /* l2_bits specifies number of entries; storing a uint64_t in each entry,
171 * so bytes = num_entries << 3. */
172 if (header
.l2_bits
< 9 - 3 || header
.l2_bits
> 16 - 3) {
173 error_setg(errp
, "L2 table size must be between 512 and 64k");
178 s
->crypt_method_header
= header
.crypt_method
;
179 if (s
->crypt_method_header
) {
180 if (bdrv_uses_whitelist() &&
181 s
->crypt_method_header
== QCOW_CRYPT_AES
) {
183 "Use of AES-CBC encrypted qcow images is no longer "
184 "supported in system emulators");
185 error_append_hint(errp
,
186 "You can use 'qemu-img convert' to convert your "
187 "image to an alternative supported format, such "
188 "as unencrypted qcow, or raw with the LUKS "
189 "format instead.\n");
193 if (s
->crypt_method_header
== QCOW_CRYPT_AES
) {
194 if (encryptfmt
&& !g_str_equal(encryptfmt
, "aes")) {
196 "Header reported 'aes' encryption format but "
197 "options specify '%s'", encryptfmt
);
201 qdict_put_str(encryptopts
, "format", "qcow");
202 crypto_opts
= block_crypto_open_opts_init(encryptopts
, errp
);
208 if (flags
& BDRV_O_NO_IO
) {
209 cflags
|= QCRYPTO_BLOCK_OPEN_NO_IO
;
211 s
->crypto
= qcrypto_block_open(crypto_opts
, "encrypt.",
212 NULL
, NULL
, cflags
, 1, errp
);
218 error_setg(errp
, "invalid encryption method in qcow header");
222 bs
->encrypted
= true;
225 error_setg(errp
, "No encryption in image header, but options "
226 "specified format '%s'", encryptfmt
);
231 s
->cluster_bits
= header
.cluster_bits
;
232 s
->cluster_size
= 1 << s
->cluster_bits
;
233 s
->l2_bits
= header
.l2_bits
;
234 s
->l2_size
= 1 << s
->l2_bits
;
235 bs
->total_sectors
= header
.size
/ 512;
236 s
->cluster_offset_mask
= (1LL << (63 - s
->cluster_bits
)) - 1;
238 /* read the level 1 table */
239 shift
= s
->cluster_bits
+ s
->l2_bits
;
240 if (header
.size
> UINT64_MAX
- (1LL << shift
)) {
241 error_setg(errp
, "Image too large");
245 uint64_t l1_size
= (header
.size
+ (1LL << shift
) - 1) >> shift
;
246 if (l1_size
> INT_MAX
/ sizeof(uint64_t)) {
247 error_setg(errp
, "Image too large");
251 s
->l1_size
= l1_size
;
254 s
->l1_table_offset
= header
.l1_table_offset
;
255 s
->l1_table
= g_try_new(uint64_t, s
->l1_size
);
256 if (s
->l1_table
== NULL
) {
257 error_setg(errp
, "Could not allocate memory for L1 table");
262 ret
= bdrv_pread(bs
->file
, s
->l1_table_offset
,
263 s
->l1_size
* sizeof(uint64_t), s
->l1_table
, 0);
268 for(i
= 0;i
< s
->l1_size
; i
++) {
269 s
->l1_table
[i
] = be64_to_cpu(s
->l1_table
[i
]);
272 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
274 qemu_try_blockalign(bs
->file
->bs
,
275 s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
276 if (s
->l2_cache
== NULL
) {
277 error_setg(errp
, "Could not allocate L2 table cache");
281 s
->cluster_cache
= g_malloc(s
->cluster_size
);
282 s
->cluster_data
= g_malloc(s
->cluster_size
);
283 s
->cluster_cache_offset
= -1;
285 /* read the backing file name */
286 if (header
.backing_file_offset
!= 0) {
287 len
= header
.backing_file_size
;
288 if (len
> 1023 || len
>= sizeof(bs
->backing_file
)) {
289 error_setg(errp
, "Backing file name too long");
293 ret
= bdrv_pread(bs
->file
, header
.backing_file_offset
, len
,
294 bs
->auto_backing_file
, 0);
298 bs
->auto_backing_file
[len
] = '\0';
299 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
),
300 bs
->auto_backing_file
);
303 /* Disable migration when qcow images are used */
304 bdrv_graph_rdlock_main_loop();
305 error_setg(&s
->migration_blocker
, "The qcow format used by node '%s' "
306 "does not support live migration",
307 bdrv_get_device_or_node_name(bs
));
308 bdrv_graph_rdunlock_main_loop();
310 ret
= migrate_add_blocker(&s
->migration_blocker
, errp
);
315 qobject_unref(encryptopts
);
316 qapi_free_QCryptoBlockOpenOptions(crypto_opts
);
317 qemu_co_mutex_init(&s
->lock
);
322 qemu_vfree(s
->l2_cache
);
323 g_free(s
->cluster_cache
);
324 g_free(s
->cluster_data
);
325 qcrypto_block_free(s
->crypto
);
326 qobject_unref(encryptopts
);
327 qapi_free_QCryptoBlockOpenOptions(crypto_opts
);
332 /* We have nothing to do for QCOW reopen, stubs just return
334 static int qcow_reopen_prepare(BDRVReopenState
*state
,
335 BlockReopenQueue
*queue
, Error
**errp
)
345 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start'
346 * to 'n_end' within the cluster)
348 * 2 to allocate a compressed cluster of size
349 * 'compressed_size'. 'compressed_size' must be > 0 and <
352 * return 0 if not allocated, 1 if *result is assigned, and negative
355 static int coroutine_fn GRAPH_RDLOCK
356 get_cluster_offset(BlockDriverState
*bs
, uint64_t offset
, int allocate
,
357 int compressed_size
, int n_start
, int n_end
,
360 BDRVQcowState
*s
= bs
->opaque
;
361 int min_index
, i
, j
, l1_index
, l2_index
, ret
;
363 uint64_t *l2_table
, cluster_offset
, tmp
;
368 l1_index
= offset
>> (s
->l2_bits
+ s
->cluster_bits
);
369 l2_offset
= s
->l1_table
[l1_index
];
374 /* allocate a new l2 entry */
375 l2_offset
= bdrv_co_getlength(bs
->file
->bs
);
379 /* round to cluster size */
380 l2_offset
= QEMU_ALIGN_UP(l2_offset
, s
->cluster_size
);
381 /* update the L1 entry */
382 s
->l1_table
[l1_index
] = l2_offset
;
383 tmp
= cpu_to_be64(l2_offset
);
384 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_L1_UPDATE
);
385 ret
= bdrv_co_pwrite_sync(bs
->file
,
386 s
->l1_table_offset
+ l1_index
* sizeof(tmp
),
387 sizeof(tmp
), &tmp
, 0);
393 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
394 if (l2_offset
== s
->l2_cache_offsets
[i
]) {
395 /* increment the hit count */
396 if (++s
->l2_cache_counts
[i
] == 0xffffffff) {
397 for(j
= 0; j
< L2_CACHE_SIZE
; j
++) {
398 s
->l2_cache_counts
[j
] >>= 1;
401 l2_table
= s
->l2_cache
+ (i
<< s
->l2_bits
);
405 /* not found: load a new entry in the least used one */
407 min_count
= 0xffffffff;
408 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
409 if (s
->l2_cache_counts
[i
] < min_count
) {
410 min_count
= s
->l2_cache_counts
[i
];
414 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
415 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_L2_LOAD
);
417 memset(l2_table
, 0, s
->l2_size
* sizeof(uint64_t));
418 ret
= bdrv_co_pwrite_sync(bs
->file
, l2_offset
,
419 s
->l2_size
* sizeof(uint64_t), l2_table
, 0);
424 ret
= bdrv_co_pread(bs
->file
, l2_offset
,
425 s
->l2_size
* sizeof(uint64_t), l2_table
, 0);
430 s
->l2_cache_offsets
[min_index
] = l2_offset
;
431 s
->l2_cache_counts
[min_index
] = 1;
433 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
434 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
435 if (!cluster_offset
||
436 ((cluster_offset
& QCOW_OFLAG_COMPRESSED
) && allocate
== 1)) {
439 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_CLUSTER_ALLOC
);
440 assert(QEMU_IS_ALIGNED(n_start
| n_end
, BDRV_SECTOR_SIZE
));
441 /* allocate a new cluster */
442 if ((cluster_offset
& QCOW_OFLAG_COMPRESSED
) &&
443 (n_end
- n_start
) < s
->cluster_size
) {
444 /* if the cluster is already compressed, we must
445 decompress it in the case it is not completely
447 if (decompress_cluster(bs
, cluster_offset
) < 0) {
450 cluster_offset
= bdrv_co_getlength(bs
->file
->bs
);
451 if ((int64_t) cluster_offset
< 0) {
452 return cluster_offset
;
454 cluster_offset
= QEMU_ALIGN_UP(cluster_offset
, s
->cluster_size
);
455 /* write the cluster content */
456 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_WRITE_AIO
);
457 ret
= bdrv_co_pwrite(bs
->file
, cluster_offset
, s
->cluster_size
,
458 s
->cluster_cache
, 0);
463 cluster_offset
= bdrv_co_getlength(bs
->file
->bs
);
464 if ((int64_t) cluster_offset
< 0) {
465 return cluster_offset
;
468 /* round to cluster size */
469 cluster_offset
= QEMU_ALIGN_UP(cluster_offset
, s
->cluster_size
);
470 if (cluster_offset
+ s
->cluster_size
> INT64_MAX
) {
473 ret
= bdrv_co_truncate(bs
->file
,
474 cluster_offset
+ s
->cluster_size
,
475 false, PREALLOC_MODE_OFF
, 0, NULL
);
479 /* if encrypted, we must initialize the cluster
480 content which won't be written */
482 (n_end
- n_start
) < s
->cluster_size
) {
483 uint64_t start_offset
;
485 start_offset
= offset
& ~(s
->cluster_size
- 1);
486 for (i
= 0; i
< s
->cluster_size
; i
+= BDRV_SECTOR_SIZE
) {
487 if (i
< n_start
|| i
>= n_end
) {
488 memset(s
->cluster_data
, 0x00, BDRV_SECTOR_SIZE
);
489 if (qcrypto_block_encrypt(s
->crypto
,
496 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_WRITE_AIO
);
497 ret
= bdrv_co_pwrite(bs
->file
, cluster_offset
+ i
,
506 } else if (allocate
== 2) {
507 cluster_offset
|= QCOW_OFLAG_COMPRESSED
|
508 (uint64_t)compressed_size
<< (63 - s
->cluster_bits
);
511 /* update L2 table */
512 tmp
= cpu_to_be64(cluster_offset
);
513 l2_table
[l2_index
] = tmp
;
515 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_L2_UPDATE_COMPRESSED
);
517 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_L2_UPDATE
);
519 ret
= bdrv_co_pwrite_sync(bs
->file
, l2_offset
+ l2_index
* sizeof(tmp
),
520 sizeof(tmp
), &tmp
, 0);
525 *result
= cluster_offset
;
529 static int coroutine_fn GRAPH_RDLOCK
530 qcow_co_block_status(BlockDriverState
*bs
, bool want_zero
,
531 int64_t offset
, int64_t bytes
, int64_t *pnum
,
532 int64_t *map
, BlockDriverState
**file
)
534 BDRVQcowState
*s
= bs
->opaque
;
535 int index_in_cluster
, ret
;
537 uint64_t cluster_offset
;
539 qemu_co_mutex_lock(&s
->lock
);
540 ret
= get_cluster_offset(bs
, offset
, 0, 0, 0, 0, &cluster_offset
);
541 qemu_co_mutex_unlock(&s
->lock
);
545 index_in_cluster
= offset
& (s
->cluster_size
- 1);
546 n
= s
->cluster_size
- index_in_cluster
;
551 if (!cluster_offset
) {
554 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
555 return BDRV_BLOCK_DATA
| BDRV_BLOCK_COMPRESSED
;
558 return BDRV_BLOCK_DATA
;
560 *map
= cluster_offset
| index_in_cluster
;
561 *file
= bs
->file
->bs
;
562 return BDRV_BLOCK_DATA
| BDRV_BLOCK_OFFSET_VALID
;
565 static int decompress_buffer(uint8_t *out_buf
, int out_buf_size
,
566 const uint8_t *buf
, int buf_size
)
568 z_stream strm1
, *strm
= &strm1
;
571 memset(strm
, 0, sizeof(*strm
));
573 strm
->next_in
= (uint8_t *)buf
;
574 strm
->avail_in
= buf_size
;
575 strm
->next_out
= out_buf
;
576 strm
->avail_out
= out_buf_size
;
578 ret
= inflateInit2(strm
, -12);
581 ret
= inflate(strm
, Z_FINISH
);
582 out_len
= strm
->next_out
- out_buf
;
583 if ((ret
!= Z_STREAM_END
&& ret
!= Z_BUF_ERROR
) ||
584 out_len
!= out_buf_size
) {
592 static int coroutine_fn GRAPH_RDLOCK
593 decompress_cluster(BlockDriverState
*bs
, uint64_t cluster_offset
)
595 BDRVQcowState
*s
= bs
->opaque
;
599 coffset
= cluster_offset
& s
->cluster_offset_mask
;
600 if (s
->cluster_cache_offset
!= coffset
) {
601 csize
= cluster_offset
>> (63 - s
->cluster_bits
);
602 csize
&= (s
->cluster_size
- 1);
603 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_READ_COMPRESSED
);
604 ret
= bdrv_co_pread(bs
->file
, coffset
, csize
, s
->cluster_data
, 0);
607 if (decompress_buffer(s
->cluster_cache
, s
->cluster_size
,
608 s
->cluster_data
, csize
) < 0) {
611 s
->cluster_cache_offset
= coffset
;
616 static void qcow_refresh_limits(BlockDriverState
*bs
, Error
**errp
)
618 /* At least encrypted images require 512-byte alignment. Apply the
619 * limit universally, rather than just on encrypted images, as
620 * it's easier to let the block layer handle rounding than to
621 * audit this code further. */
622 bs
->bl
.request_alignment
= BDRV_SECTOR_SIZE
;
625 static int coroutine_fn GRAPH_RDLOCK
626 qcow_co_preadv(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
627 QEMUIOVector
*qiov
, BdrvRequestFlags flags
)
629 BDRVQcowState
*s
= bs
->opaque
;
630 int offset_in_cluster
;
632 uint64_t cluster_offset
;
636 if (qiov
->niov
> 1) {
637 buf
= orig_buf
= qemu_try_blockalign(bs
, qiov
->size
);
643 buf
= (uint8_t *)qiov
->iov
->iov_base
;
646 qemu_co_mutex_lock(&s
->lock
);
649 /* prepare next request */
650 ret
= get_cluster_offset(bs
, offset
, 0, 0, 0, 0, &cluster_offset
);
654 offset_in_cluster
= offset
& (s
->cluster_size
- 1);
655 n
= s
->cluster_size
- offset_in_cluster
;
660 if (!cluster_offset
) {
662 /* read from the base image */
663 qemu_co_mutex_unlock(&s
->lock
);
664 /* qcow2 emits this on bs->file instead of bs->backing */
665 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_READ_BACKING_AIO
);
666 ret
= bdrv_co_pread(bs
->backing
, offset
, n
, buf
, 0);
667 qemu_co_mutex_lock(&s
->lock
);
672 /* Note: in this case, no need to wait */
675 } else if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
676 /* add AIO support for compressed blocks ? */
677 if (decompress_cluster(bs
, cluster_offset
) < 0) {
681 memcpy(buf
, s
->cluster_cache
+ offset_in_cluster
, n
);
683 if ((cluster_offset
& 511) != 0) {
687 qemu_co_mutex_unlock(&s
->lock
);
688 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_READ_AIO
);
689 ret
= bdrv_co_pread(bs
->file
, cluster_offset
+ offset_in_cluster
,
691 qemu_co_mutex_lock(&s
->lock
);
697 if (qcrypto_block_decrypt(s
->crypto
,
698 offset
, buf
, n
, NULL
) < 0) {
711 qemu_co_mutex_unlock(&s
->lock
);
713 if (qiov
->niov
> 1) {
714 qemu_iovec_from_buf(qiov
, 0, orig_buf
, qiov
->size
);
715 qemu_vfree(orig_buf
);
721 static int coroutine_fn GRAPH_RDLOCK
722 qcow_co_pwritev(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
723 QEMUIOVector
*qiov
, BdrvRequestFlags flags
)
725 BDRVQcowState
*s
= bs
->opaque
;
726 int offset_in_cluster
;
727 uint64_t cluster_offset
;
732 s
->cluster_cache_offset
= -1; /* disable compressed cache */
734 /* We must always copy the iov when encrypting, so we
735 * don't modify the original data buffer during encryption */
736 if (bs
->encrypted
|| qiov
->niov
> 1) {
737 buf
= orig_buf
= qemu_try_blockalign(bs
, qiov
->size
);
741 qemu_iovec_to_buf(qiov
, 0, buf
, qiov
->size
);
744 buf
= (uint8_t *)qiov
->iov
->iov_base
;
747 qemu_co_mutex_lock(&s
->lock
);
750 offset_in_cluster
= offset
& (s
->cluster_size
- 1);
751 n
= s
->cluster_size
- offset_in_cluster
;
755 ret
= get_cluster_offset(bs
, offset
, 1, 0, offset_in_cluster
,
756 offset_in_cluster
+ n
, &cluster_offset
);
760 if (!cluster_offset
|| (cluster_offset
& 511) != 0) {
766 if (qcrypto_block_encrypt(s
->crypto
, offset
, buf
, n
, NULL
) < 0) {
772 qemu_co_mutex_unlock(&s
->lock
);
773 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_WRITE_AIO
);
774 ret
= bdrv_co_pwrite(bs
->file
, cluster_offset
+ offset_in_cluster
,
776 qemu_co_mutex_lock(&s
->lock
);
786 qemu_co_mutex_unlock(&s
->lock
);
788 qemu_vfree(orig_buf
);
793 static void qcow_close(BlockDriverState
*bs
)
795 BDRVQcowState
*s
= bs
->opaque
;
797 qcrypto_block_free(s
->crypto
);
800 qemu_vfree(s
->l2_cache
);
801 g_free(s
->cluster_cache
);
802 g_free(s
->cluster_data
);
804 migrate_del_blocker(&s
->migration_blocker
);
807 static int coroutine_fn GRAPH_UNLOCKED
808 qcow_co_create(BlockdevCreateOptions
*opts
, Error
**errp
)
810 BlockdevCreateOptionsQcow
*qcow_opts
;
811 int header_size
, backing_filename_len
, l1_size
, shift
, i
;
814 int64_t total_size
= 0;
816 BlockDriverState
*bs
;
817 BlockBackend
*qcow_blk
;
818 QCryptoBlock
*crypto
= NULL
;
820 assert(opts
->driver
== BLOCKDEV_DRIVER_QCOW
);
821 qcow_opts
= &opts
->u
.qcow
;
824 total_size
= qcow_opts
->size
;
825 if (total_size
== 0) {
826 error_setg(errp
, "Image size is too small, cannot be zero length");
830 if (qcow_opts
->encrypt
&&
831 qcow_opts
->encrypt
->format
!= Q_CRYPTO_BLOCK_FORMAT_QCOW
)
833 error_setg(errp
, "Unsupported encryption format");
837 /* Create BlockBackend to write to the image */
838 bs
= bdrv_co_open_blockdev_ref(qcow_opts
->file
, errp
);
843 qcow_blk
= blk_co_new_with_bs(bs
, BLK_PERM_WRITE
| BLK_PERM_RESIZE
,
849 blk_set_allow_write_beyond_eof(qcow_blk
, true);
851 /* Create image format */
852 memset(&header
, 0, sizeof(header
));
853 header
.magic
= cpu_to_be32(QCOW_MAGIC
);
854 header
.version
= cpu_to_be32(QCOW_VERSION
);
855 header
.size
= cpu_to_be64(total_size
);
856 header_size
= sizeof(header
);
857 backing_filename_len
= 0;
858 if (qcow_opts
->backing_file
) {
859 if (strcmp(qcow_opts
->backing_file
, "fat:")) {
860 header
.backing_file_offset
= cpu_to_be64(header_size
);
861 backing_filename_len
= strlen(qcow_opts
->backing_file
);
862 header
.backing_file_size
= cpu_to_be32(backing_filename_len
);
863 header_size
+= backing_filename_len
;
865 /* special backing file for vvfat */
866 qcow_opts
->backing_file
= NULL
;
868 header
.cluster_bits
= 9; /* 512 byte cluster to avoid copying
869 unmodified sectors */
870 header
.l2_bits
= 12; /* 32 KB L2 tables */
872 header
.cluster_bits
= 12; /* 4 KB clusters */
873 header
.l2_bits
= 9; /* 4 KB L2 tables */
875 header_size
= (header_size
+ 7) & ~7;
876 shift
= header
.cluster_bits
+ header
.l2_bits
;
877 l1_size
= (total_size
+ (1LL << shift
) - 1) >> shift
;
879 header
.l1_table_offset
= cpu_to_be64(header_size
);
881 if (qcow_opts
->encrypt
) {
882 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_AES
);
884 crypto
= qcrypto_block_create(qcow_opts
->encrypt
, "encrypt.",
885 NULL
, NULL
, NULL
, errp
);
891 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
894 /* write all the data */
895 ret
= blk_co_pwrite(qcow_blk
, 0, sizeof(header
), &header
, 0);
900 if (qcow_opts
->backing_file
) {
901 ret
= blk_co_pwrite(qcow_blk
, sizeof(header
), backing_filename_len
,
902 qcow_opts
->backing_file
, 0);
908 tmp
= g_malloc0(BDRV_SECTOR_SIZE
);
909 for (i
= 0; i
< DIV_ROUND_UP(sizeof(uint64_t) * l1_size
, BDRV_SECTOR_SIZE
);
911 ret
= blk_co_pwrite(qcow_blk
, header_size
+ BDRV_SECTOR_SIZE
* i
,
912 BDRV_SECTOR_SIZE
, tmp
, 0);
922 blk_co_unref(qcow_blk
);
924 qcrypto_block_free(crypto
);
928 static int coroutine_fn GRAPH_UNLOCKED
929 qcow_co_create_opts(BlockDriver
*drv
, const char *filename
,
930 QemuOpts
*opts
, Error
**errp
)
932 BlockdevCreateOptions
*create_options
= NULL
;
933 BlockDriverState
*bs
= NULL
;
940 static const QDictRenames opt_renames
[] = {
941 { BLOCK_OPT_BACKING_FILE
, "backing-file" },
942 { BLOCK_OPT_ENCRYPT
, BLOCK_OPT_ENCRYPT_FORMAT
},
947 * We can't actually store a backing format, but can check that
948 * the user's request made sense.
950 backing_fmt
= qemu_opt_get_del(opts
, BLOCK_OPT_BACKING_FMT
);
951 if (backing_fmt
&& !bdrv_find_format(backing_fmt
)) {
952 error_setg(errp
, "unrecognized backing format '%s'", backing_fmt
);
957 /* Parse options and convert legacy syntax */
958 qdict
= qemu_opts_to_qdict_filtered(opts
, NULL
, &qcow_create_opts
, true);
960 val
= qdict_get_try_str(qdict
, BLOCK_OPT_ENCRYPT
);
961 if (val
&& !strcmp(val
, "on")) {
962 qdict_put_str(qdict
, BLOCK_OPT_ENCRYPT
, "qcow");
963 } else if (val
&& !strcmp(val
, "off")) {
964 qdict_del(qdict
, BLOCK_OPT_ENCRYPT
);
967 val
= qdict_get_try_str(qdict
, BLOCK_OPT_ENCRYPT_FORMAT
);
968 if (val
&& !strcmp(val
, "aes")) {
969 qdict_put_str(qdict
, BLOCK_OPT_ENCRYPT_FORMAT
, "qcow");
972 if (!qdict_rename_keys(qdict
, opt_renames
, errp
)) {
977 /* Create and open the file (protocol layer) */
978 ret
= bdrv_co_create_file(filename
, opts
, errp
);
983 bs
= bdrv_co_open(filename
, NULL
, NULL
,
984 BDRV_O_RDWR
| BDRV_O_RESIZE
| BDRV_O_PROTOCOL
, errp
);
990 /* Now get the QAPI type BlockdevCreateOptions */
991 qdict_put_str(qdict
, "driver", "qcow");
992 qdict_put_str(qdict
, "file", bs
->node_name
);
994 v
= qobject_input_visitor_new_flat_confused(qdict
, errp
);
1000 visit_type_BlockdevCreateOptions(v
, NULL
, &create_options
, errp
);
1002 if (!create_options
) {
1007 /* Silently round up size */
1008 assert(create_options
->driver
== BLOCKDEV_DRIVER_QCOW
);
1009 create_options
->u
.qcow
.size
=
1010 ROUND_UP(create_options
->u
.qcow
.size
, BDRV_SECTOR_SIZE
);
1012 /* Create the qcow image (format layer) */
1013 ret
= qcow_co_create(create_options
, errp
);
1020 g_free(backing_fmt
);
1021 qobject_unref(qdict
);
1023 qapi_free_BlockdevCreateOptions(create_options
);
1027 static int qcow_make_empty(BlockDriverState
*bs
)
1029 BDRVQcowState
*s
= bs
->opaque
;
1030 uint32_t l1_length
= s
->l1_size
* sizeof(uint64_t);
1033 memset(s
->l1_table
, 0, l1_length
);
1034 if (bdrv_pwrite_sync(bs
->file
, s
->l1_table_offset
, l1_length
, s
->l1_table
,
1037 ret
= bdrv_truncate(bs
->file
, s
->l1_table_offset
+ l1_length
, false,
1038 PREALLOC_MODE_OFF
, 0, NULL
);
1042 memset(s
->l2_cache
, 0, s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
1043 memset(s
->l2_cache_offsets
, 0, L2_CACHE_SIZE
* sizeof(uint64_t));
1044 memset(s
->l2_cache_counts
, 0, L2_CACHE_SIZE
* sizeof(uint32_t));
1049 /* XXX: put compressed sectors first, then all the cluster aligned
1050 tables to avoid losing bytes in alignment */
1051 static int coroutine_fn GRAPH_RDLOCK
1052 qcow_co_pwritev_compressed(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
1055 BDRVQcowState
*s
= bs
->opaque
;
1058 uint8_t *buf
, *out_buf
;
1059 uint64_t cluster_offset
;
1061 buf
= qemu_blockalign(bs
, s
->cluster_size
);
1062 if (bytes
!= s
->cluster_size
) {
1063 if (bytes
> s
->cluster_size
||
1064 offset
+ bytes
!= bs
->total_sectors
<< BDRV_SECTOR_BITS
)
1069 /* Zero-pad last write if image size is not cluster aligned */
1070 memset(buf
+ bytes
, 0, s
->cluster_size
- bytes
);
1072 qemu_iovec_to_buf(qiov
, 0, buf
, qiov
->size
);
1074 out_buf
= g_malloc(s
->cluster_size
);
1076 /* best compression, small window, no zlib header */
1077 memset(&strm
, 0, sizeof(strm
));
1078 ret
= deflateInit2(&strm
, Z_DEFAULT_COMPRESSION
,
1080 9, Z_DEFAULT_STRATEGY
);
1086 strm
.avail_in
= s
->cluster_size
;
1087 strm
.next_in
= (uint8_t *)buf
;
1088 strm
.avail_out
= s
->cluster_size
;
1089 strm
.next_out
= out_buf
;
1091 ret
= deflate(&strm
, Z_FINISH
);
1092 if (ret
!= Z_STREAM_END
&& ret
!= Z_OK
) {
1097 out_len
= strm
.next_out
- out_buf
;
1101 if (ret
!= Z_STREAM_END
|| out_len
>= s
->cluster_size
) {
1102 /* could not compress: write normal cluster */
1103 ret
= qcow_co_pwritev(bs
, offset
, bytes
, qiov
, 0);
1109 qemu_co_mutex_lock(&s
->lock
);
1110 ret
= get_cluster_offset(bs
, offset
, 2, out_len
, 0, 0, &cluster_offset
);
1111 qemu_co_mutex_unlock(&s
->lock
);
1115 if (cluster_offset
== 0) {
1119 cluster_offset
&= s
->cluster_offset_mask
;
1121 BLKDBG_CO_EVENT(bs
->file
, BLKDBG_WRITE_COMPRESSED
);
1122 ret
= bdrv_co_pwrite(bs
->file
, cluster_offset
, out_len
, out_buf
, 0);
1134 static int coroutine_fn
1135 qcow_co_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
1137 BDRVQcowState
*s
= bs
->opaque
;
1138 bdi
->cluster_size
= s
->cluster_size
;
1142 static QemuOptsList qcow_create_opts
= {
1143 .name
= "qcow-create-opts",
1144 .head
= QTAILQ_HEAD_INITIALIZER(qcow_create_opts
.head
),
1147 .name
= BLOCK_OPT_SIZE
,
1148 .type
= QEMU_OPT_SIZE
,
1149 .help
= "Virtual disk size"
1152 .name
= BLOCK_OPT_BACKING_FILE
,
1153 .type
= QEMU_OPT_STRING
,
1154 .help
= "File name of a base image"
1157 .name
= BLOCK_OPT_BACKING_FMT
,
1158 .type
= QEMU_OPT_STRING
,
1159 .help
= "Format of the backing image",
1162 .name
= BLOCK_OPT_ENCRYPT
,
1163 .type
= QEMU_OPT_BOOL
,
1164 .help
= "Encrypt the image with format 'aes'. (Deprecated "
1165 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT
"=aes)",
1168 .name
= BLOCK_OPT_ENCRYPT_FORMAT
,
1169 .type
= QEMU_OPT_STRING
,
1170 .help
= "Encrypt the image, format choices: 'aes'",
1172 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1173 { /* end of list */ }
1177 static const char *const qcow_strong_runtime_opts
[] = {
1178 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET
,
1183 static BlockDriver bdrv_qcow
= {
1184 .format_name
= "qcow",
1185 .instance_size
= sizeof(BDRVQcowState
),
1186 .bdrv_probe
= qcow_probe
,
1187 .bdrv_open
= qcow_open
,
1188 .bdrv_close
= qcow_close
,
1189 .bdrv_child_perm
= bdrv_default_perms
,
1190 .bdrv_reopen_prepare
= qcow_reopen_prepare
,
1191 .bdrv_co_create
= qcow_co_create
,
1192 .bdrv_co_create_opts
= qcow_co_create_opts
,
1193 .bdrv_has_zero_init
= bdrv_has_zero_init_1
,
1195 .supports_backing
= true,
1196 .bdrv_refresh_limits
= qcow_refresh_limits
,
1198 .bdrv_co_preadv
= qcow_co_preadv
,
1199 .bdrv_co_pwritev
= qcow_co_pwritev
,
1200 .bdrv_co_block_status
= qcow_co_block_status
,
1202 .bdrv_make_empty
= qcow_make_empty
,
1203 .bdrv_co_pwritev_compressed
= qcow_co_pwritev_compressed
,
1204 .bdrv_co_get_info
= qcow_co_get_info
,
1206 .create_opts
= &qcow_create_opts
,
1207 .strong_runtime_opts
= qcow_strong_runtime_opts
,
1210 static void bdrv_qcow_init(void)
1212 bdrv_register(&bdrv_qcow
);
1215 block_init(bdrv_qcow_init
);