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
25 #include "qemu/osdep.h"
30 #include "block/block_int.h"
31 #include "block/qdict.h"
32 #include "sysemu/block-backend.h"
33 #include "qemu/module.h"
35 #include "qemu/error-report.h"
36 #include "qapi/error.h"
37 #include "qapi/qapi-events-block-core.h"
38 #include "qapi/qmp/qdict.h"
39 #include "qapi/qmp/qstring.h"
41 #include "qemu/option_int.h"
42 #include "qemu/cutils.h"
43 #include "qemu/bswap.h"
44 #include "qapi/qobject-input-visitor.h"
45 #include "qapi/qapi-visit-block-core.h"
47 #include "block/thread-pool.h"
50 Differences with QCOW:
52 - Support for multiple incremental snapshots.
53 - Memory management by reference counts.
54 - Clusters which have a reference count of one have the bit
55 QCOW_OFLAG_COPIED to optimize write performance.
56 - Size of compressed clusters is stored in sectors to reduce bit usage
57 in the cluster offsets.
58 - Support for storing additional data (such as the VM state) in the
60 - If a backing store is used, the cluster size is not constrained
61 (could be backported to QCOW).
62 - L2 tables have always a size of one cluster.
69 } QEMU_PACKED QCowExtension
;
71 #define QCOW2_EXT_MAGIC_END 0
72 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
73 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
74 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77
75 #define QCOW2_EXT_MAGIC_BITMAPS 0x23852875
77 static int coroutine_fn
78 qcow2_co_preadv_compressed(BlockDriverState
*bs
,
79 uint64_t file_cluster_offset
,
84 static int qcow2_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
86 const QCowHeader
*cow_header
= (const void *)buf
;
88 if (buf_size
>= sizeof(QCowHeader
) &&
89 be32_to_cpu(cow_header
->magic
) == QCOW_MAGIC
&&
90 be32_to_cpu(cow_header
->version
) >= 2)
97 static ssize_t
qcow2_crypto_hdr_read_func(QCryptoBlock
*block
, size_t offset
,
98 uint8_t *buf
, size_t buflen
,
99 void *opaque
, Error
**errp
)
101 BlockDriverState
*bs
= opaque
;
102 BDRVQcow2State
*s
= bs
->opaque
;
105 if ((offset
+ buflen
) > s
->crypto_header
.length
) {
106 error_setg(errp
, "Request for data outside of extension header");
110 ret
= bdrv_pread(bs
->file
,
111 s
->crypto_header
.offset
+ offset
, buf
, buflen
);
113 error_setg_errno(errp
, -ret
, "Could not read encryption header");
120 static ssize_t
qcow2_crypto_hdr_init_func(QCryptoBlock
*block
, size_t headerlen
,
121 void *opaque
, Error
**errp
)
123 BlockDriverState
*bs
= opaque
;
124 BDRVQcow2State
*s
= bs
->opaque
;
128 ret
= qcow2_alloc_clusters(bs
, headerlen
);
130 error_setg_errno(errp
, -ret
,
131 "Cannot allocate cluster for LUKS header size %zu",
136 s
->crypto_header
.length
= headerlen
;
137 s
->crypto_header
.offset
= ret
;
139 /* Zero fill remaining space in cluster so it has predictable
140 * content in case of future spec changes */
141 clusterlen
= size_to_clusters(s
, headerlen
) * s
->cluster_size
;
142 assert(qcow2_pre_write_overlap_check(bs
, 0, ret
, clusterlen
) == 0);
143 ret
= bdrv_pwrite_zeroes(bs
->file
,
145 clusterlen
- headerlen
, 0);
147 error_setg_errno(errp
, -ret
, "Could not zero fill encryption header");
155 static ssize_t
qcow2_crypto_hdr_write_func(QCryptoBlock
*block
, size_t offset
,
156 const uint8_t *buf
, size_t buflen
,
157 void *opaque
, Error
**errp
)
159 BlockDriverState
*bs
= opaque
;
160 BDRVQcow2State
*s
= bs
->opaque
;
163 if ((offset
+ buflen
) > s
->crypto_header
.length
) {
164 error_setg(errp
, "Request for data outside of extension header");
168 ret
= bdrv_pwrite(bs
->file
,
169 s
->crypto_header
.offset
+ offset
, buf
, buflen
);
171 error_setg_errno(errp
, -ret
, "Could not read encryption header");
179 * read qcow2 extension and fill bs
180 * start reading from start_offset
181 * finish reading upon magic of value 0 or when end_offset reached
182 * unknown magic is skipped (future extension this version knows nothing about)
183 * return 0 upon success, non-0 otherwise
185 static int qcow2_read_extensions(BlockDriverState
*bs
, uint64_t start_offset
,
186 uint64_t end_offset
, void **p_feature_table
,
187 int flags
, bool *need_update_header
,
190 BDRVQcow2State
*s
= bs
->opaque
;
194 Qcow2BitmapHeaderExt bitmaps_ext
;
196 if (need_update_header
!= NULL
) {
197 *need_update_header
= false;
201 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset
, end_offset
);
203 offset
= start_offset
;
204 while (offset
< end_offset
) {
208 if (offset
> s
->cluster_size
)
209 printf("qcow2_read_extension: suspicious offset %lu\n", offset
);
211 printf("attempting to read extended header in offset %lu\n", offset
);
214 ret
= bdrv_pread(bs
->file
, offset
, &ext
, sizeof(ext
));
216 error_setg_errno(errp
, -ret
, "qcow2_read_extension: ERROR: "
217 "pread fail from offset %" PRIu64
, offset
);
220 ext
.magic
= be32_to_cpu(ext
.magic
);
221 ext
.len
= be32_to_cpu(ext
.len
);
222 offset
+= sizeof(ext
);
224 printf("ext.magic = 0x%x\n", ext
.magic
);
226 if (offset
> end_offset
|| ext
.len
> end_offset
- offset
) {
227 error_setg(errp
, "Header extension too large");
232 case QCOW2_EXT_MAGIC_END
:
235 case QCOW2_EXT_MAGIC_BACKING_FORMAT
:
236 if (ext
.len
>= sizeof(bs
->backing_format
)) {
237 error_setg(errp
, "ERROR: ext_backing_format: len=%" PRIu32
238 " too large (>=%zu)", ext
.len
,
239 sizeof(bs
->backing_format
));
242 ret
= bdrv_pread(bs
->file
, offset
, bs
->backing_format
, ext
.len
);
244 error_setg_errno(errp
, -ret
, "ERROR: ext_backing_format: "
245 "Could not read format name");
248 bs
->backing_format
[ext
.len
] = '\0';
249 s
->image_backing_format
= g_strdup(bs
->backing_format
);
251 printf("Qcow2: Got format extension %s\n", bs
->backing_format
);
255 case QCOW2_EXT_MAGIC_FEATURE_TABLE
:
256 if (p_feature_table
!= NULL
) {
257 void* feature_table
= g_malloc0(ext
.len
+ 2 * sizeof(Qcow2Feature
));
258 ret
= bdrv_pread(bs
->file
, offset
, feature_table
, ext
.len
);
260 error_setg_errno(errp
, -ret
, "ERROR: ext_feature_table: "
261 "Could not read table");
265 *p_feature_table
= feature_table
;
269 case QCOW2_EXT_MAGIC_CRYPTO_HEADER
: {
270 unsigned int cflags
= 0;
271 if (s
->crypt_method_header
!= QCOW_CRYPT_LUKS
) {
272 error_setg(errp
, "CRYPTO header extension only "
273 "expected with LUKS encryption method");
276 if (ext
.len
!= sizeof(Qcow2CryptoHeaderExtension
)) {
277 error_setg(errp
, "CRYPTO header extension size %u, "
278 "but expected size %zu", ext
.len
,
279 sizeof(Qcow2CryptoHeaderExtension
));
283 ret
= bdrv_pread(bs
->file
, offset
, &s
->crypto_header
, ext
.len
);
285 error_setg_errno(errp
, -ret
,
286 "Unable to read CRYPTO header extension");
289 s
->crypto_header
.offset
= be64_to_cpu(s
->crypto_header
.offset
);
290 s
->crypto_header
.length
= be64_to_cpu(s
->crypto_header
.length
);
292 if ((s
->crypto_header
.offset
% s
->cluster_size
) != 0) {
293 error_setg(errp
, "Encryption header offset '%" PRIu64
"' is "
294 "not a multiple of cluster size '%u'",
295 s
->crypto_header
.offset
, s
->cluster_size
);
299 if (flags
& BDRV_O_NO_IO
) {
300 cflags
|= QCRYPTO_BLOCK_OPEN_NO_IO
;
302 s
->crypto
= qcrypto_block_open(s
->crypto_opts
, "encrypt.",
303 qcow2_crypto_hdr_read_func
,
304 bs
, cflags
, 1, errp
);
310 case QCOW2_EXT_MAGIC_BITMAPS
:
311 if (ext
.len
!= sizeof(bitmaps_ext
)) {
312 error_setg_errno(errp
, -ret
, "bitmaps_ext: "
313 "Invalid extension length");
317 if (!(s
->autoclear_features
& QCOW2_AUTOCLEAR_BITMAPS
)) {
318 if (s
->qcow_version
< 3) {
319 /* Let's be a bit more specific */
320 warn_report("This qcow2 v2 image contains bitmaps, but "
321 "they may have been modified by a program "
322 "without persistent bitmap support; so now "
323 "they must all be considered inconsistent");
325 warn_report("a program lacking bitmap support "
326 "modified this file, so all bitmaps are now "
327 "considered inconsistent");
329 error_printf("Some clusters may be leaked, "
330 "run 'qemu-img check -r' on the image "
332 if (need_update_header
!= NULL
) {
333 /* Updating is needed to drop invalid bitmap extension. */
334 *need_update_header
= true;
339 ret
= bdrv_pread(bs
->file
, offset
, &bitmaps_ext
, ext
.len
);
341 error_setg_errno(errp
, -ret
, "bitmaps_ext: "
342 "Could not read ext header");
346 if (bitmaps_ext
.reserved32
!= 0) {
347 error_setg_errno(errp
, -ret
, "bitmaps_ext: "
348 "Reserved field is not zero");
352 bitmaps_ext
.nb_bitmaps
= be32_to_cpu(bitmaps_ext
.nb_bitmaps
);
353 bitmaps_ext
.bitmap_directory_size
=
354 be64_to_cpu(bitmaps_ext
.bitmap_directory_size
);
355 bitmaps_ext
.bitmap_directory_offset
=
356 be64_to_cpu(bitmaps_ext
.bitmap_directory_offset
);
358 if (bitmaps_ext
.nb_bitmaps
> QCOW2_MAX_BITMAPS
) {
360 "bitmaps_ext: Image has %" PRIu32
" bitmaps, "
361 "exceeding the QEMU supported maximum of %d",
362 bitmaps_ext
.nb_bitmaps
, QCOW2_MAX_BITMAPS
);
366 if (bitmaps_ext
.nb_bitmaps
== 0) {
367 error_setg(errp
, "found bitmaps extension with zero bitmaps");
371 if (bitmaps_ext
.bitmap_directory_offset
& (s
->cluster_size
- 1)) {
372 error_setg(errp
, "bitmaps_ext: "
373 "invalid bitmap directory offset");
377 if (bitmaps_ext
.bitmap_directory_size
>
378 QCOW2_MAX_BITMAP_DIRECTORY_SIZE
) {
379 error_setg(errp
, "bitmaps_ext: "
380 "bitmap directory size (%" PRIu64
") exceeds "
381 "the maximum supported size (%d)",
382 bitmaps_ext
.bitmap_directory_size
,
383 QCOW2_MAX_BITMAP_DIRECTORY_SIZE
);
387 s
->nb_bitmaps
= bitmaps_ext
.nb_bitmaps
;
388 s
->bitmap_directory_offset
=
389 bitmaps_ext
.bitmap_directory_offset
;
390 s
->bitmap_directory_size
=
391 bitmaps_ext
.bitmap_directory_size
;
394 printf("Qcow2: Got bitmaps extension: "
395 "offset=%" PRIu64
" nb_bitmaps=%" PRIu32
"\n",
396 s
->bitmap_directory_offset
, s
->nb_bitmaps
);
401 /* unknown magic - save it in case we need to rewrite the header */
402 /* If you add a new feature, make sure to also update the fast
403 * path of qcow2_make_empty() to deal with it. */
405 Qcow2UnknownHeaderExtension
*uext
;
407 uext
= g_malloc0(sizeof(*uext
) + ext
.len
);
408 uext
->magic
= ext
.magic
;
410 QLIST_INSERT_HEAD(&s
->unknown_header_ext
, uext
, next
);
412 ret
= bdrv_pread(bs
->file
, offset
, uext
->data
, uext
->len
);
414 error_setg_errno(errp
, -ret
, "ERROR: unknown extension: "
415 "Could not read data");
422 offset
+= ((ext
.len
+ 7) & ~7);
428 static void cleanup_unknown_header_ext(BlockDriverState
*bs
)
430 BDRVQcow2State
*s
= bs
->opaque
;
431 Qcow2UnknownHeaderExtension
*uext
, *next
;
433 QLIST_FOREACH_SAFE(uext
, &s
->unknown_header_ext
, next
, next
) {
434 QLIST_REMOVE(uext
, next
);
439 static void report_unsupported_feature(Error
**errp
, Qcow2Feature
*table
,
442 char *features
= g_strdup("");
445 while (table
&& table
->name
[0] != '\0') {
446 if (table
->type
== QCOW2_FEAT_TYPE_INCOMPATIBLE
) {
447 if (mask
& (1ULL << table
->bit
)) {
449 features
= g_strdup_printf("%s%s%.46s", old
, *old
? ", " : "",
452 mask
&= ~(1ULL << table
->bit
);
460 features
= g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64
,
461 old
, *old
? ", " : "", mask
);
465 error_setg(errp
, "Unsupported qcow2 feature(s): %s", features
);
470 * Sets the dirty bit and flushes afterwards if necessary.
472 * The incompatible_features bit is only set if the image file header was
473 * updated successfully. Therefore it is not required to check the return
474 * value of this function.
476 int qcow2_mark_dirty(BlockDriverState
*bs
)
478 BDRVQcow2State
*s
= bs
->opaque
;
482 assert(s
->qcow_version
>= 3);
484 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
485 return 0; /* already dirty */
488 val
= cpu_to_be64(s
->incompatible_features
| QCOW2_INCOMPAT_DIRTY
);
489 ret
= bdrv_pwrite(bs
->file
, offsetof(QCowHeader
, incompatible_features
),
494 ret
= bdrv_flush(bs
->file
->bs
);
499 /* Only treat image as dirty if the header was updated successfully */
500 s
->incompatible_features
|= QCOW2_INCOMPAT_DIRTY
;
505 * Clears the dirty bit and flushes before if necessary. Only call this
506 * function when there are no pending requests, it does not guard against
507 * concurrent requests dirtying the image.
509 static int qcow2_mark_clean(BlockDriverState
*bs
)
511 BDRVQcow2State
*s
= bs
->opaque
;
513 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
516 s
->incompatible_features
&= ~QCOW2_INCOMPAT_DIRTY
;
518 ret
= qcow2_flush_caches(bs
);
523 return qcow2_update_header(bs
);
529 * Marks the image as corrupt.
531 int qcow2_mark_corrupt(BlockDriverState
*bs
)
533 BDRVQcow2State
*s
= bs
->opaque
;
535 s
->incompatible_features
|= QCOW2_INCOMPAT_CORRUPT
;
536 return qcow2_update_header(bs
);
540 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
541 * before if necessary.
543 int qcow2_mark_consistent(BlockDriverState
*bs
)
545 BDRVQcow2State
*s
= bs
->opaque
;
547 if (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
) {
548 int ret
= qcow2_flush_caches(bs
);
553 s
->incompatible_features
&= ~QCOW2_INCOMPAT_CORRUPT
;
554 return qcow2_update_header(bs
);
559 static int coroutine_fn
qcow2_co_check_locked(BlockDriverState
*bs
,
560 BdrvCheckResult
*result
,
563 int ret
= qcow2_check_refcounts(bs
, result
, fix
);
568 if (fix
&& result
->check_errors
== 0 && result
->corruptions
== 0) {
569 ret
= qcow2_mark_clean(bs
);
573 return qcow2_mark_consistent(bs
);
578 static int coroutine_fn
qcow2_co_check(BlockDriverState
*bs
,
579 BdrvCheckResult
*result
,
582 BDRVQcow2State
*s
= bs
->opaque
;
585 qemu_co_mutex_lock(&s
->lock
);
586 ret
= qcow2_co_check_locked(bs
, result
, fix
);
587 qemu_co_mutex_unlock(&s
->lock
);
591 int qcow2_validate_table(BlockDriverState
*bs
, uint64_t offset
,
592 uint64_t entries
, size_t entry_len
,
593 int64_t max_size_bytes
, const char *table_name
,
596 BDRVQcow2State
*s
= bs
->opaque
;
598 if (entries
> max_size_bytes
/ entry_len
) {
599 error_setg(errp
, "%s too large", table_name
);
603 /* Use signed INT64_MAX as the maximum even for uint64_t header fields,
604 * because values will be passed to qemu functions taking int64_t. */
605 if ((INT64_MAX
- entries
* entry_len
< offset
) ||
606 (offset_into_cluster(s
, offset
) != 0)) {
607 error_setg(errp
, "%s offset invalid", table_name
);
614 static QemuOptsList qcow2_runtime_opts
= {
616 .head
= QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts
.head
),
619 .name
= QCOW2_OPT_LAZY_REFCOUNTS
,
620 .type
= QEMU_OPT_BOOL
,
621 .help
= "Postpone refcount updates",
624 .name
= QCOW2_OPT_DISCARD_REQUEST
,
625 .type
= QEMU_OPT_BOOL
,
626 .help
= "Pass guest discard requests to the layer below",
629 .name
= QCOW2_OPT_DISCARD_SNAPSHOT
,
630 .type
= QEMU_OPT_BOOL
,
631 .help
= "Generate discard requests when snapshot related space "
635 .name
= QCOW2_OPT_DISCARD_OTHER
,
636 .type
= QEMU_OPT_BOOL
,
637 .help
= "Generate discard requests when other clusters are freed",
640 .name
= QCOW2_OPT_OVERLAP
,
641 .type
= QEMU_OPT_STRING
,
642 .help
= "Selects which overlap checks to perform from a range of "
643 "templates (none, constant, cached, all)",
646 .name
= QCOW2_OPT_OVERLAP_TEMPLATE
,
647 .type
= QEMU_OPT_STRING
,
648 .help
= "Selects which overlap checks to perform from a range of "
649 "templates (none, constant, cached, all)",
652 .name
= QCOW2_OPT_OVERLAP_MAIN_HEADER
,
653 .type
= QEMU_OPT_BOOL
,
654 .help
= "Check for unintended writes into the main qcow2 header",
657 .name
= QCOW2_OPT_OVERLAP_ACTIVE_L1
,
658 .type
= QEMU_OPT_BOOL
,
659 .help
= "Check for unintended writes into the active L1 table",
662 .name
= QCOW2_OPT_OVERLAP_ACTIVE_L2
,
663 .type
= QEMU_OPT_BOOL
,
664 .help
= "Check for unintended writes into an active L2 table",
667 .name
= QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
,
668 .type
= QEMU_OPT_BOOL
,
669 .help
= "Check for unintended writes into the refcount table",
672 .name
= QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
,
673 .type
= QEMU_OPT_BOOL
,
674 .help
= "Check for unintended writes into a refcount block",
677 .name
= QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
,
678 .type
= QEMU_OPT_BOOL
,
679 .help
= "Check for unintended writes into the snapshot table",
682 .name
= QCOW2_OPT_OVERLAP_INACTIVE_L1
,
683 .type
= QEMU_OPT_BOOL
,
684 .help
= "Check for unintended writes into an inactive L1 table",
687 .name
= QCOW2_OPT_OVERLAP_INACTIVE_L2
,
688 .type
= QEMU_OPT_BOOL
,
689 .help
= "Check for unintended writes into an inactive L2 table",
692 .name
= QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY
,
693 .type
= QEMU_OPT_BOOL
,
694 .help
= "Check for unintended writes into the bitmap directory",
697 .name
= QCOW2_OPT_CACHE_SIZE
,
698 .type
= QEMU_OPT_SIZE
,
699 .help
= "Maximum combined metadata (L2 tables and refcount blocks) "
703 .name
= QCOW2_OPT_L2_CACHE_SIZE
,
704 .type
= QEMU_OPT_SIZE
,
705 .help
= "Maximum L2 table cache size",
708 .name
= QCOW2_OPT_L2_CACHE_ENTRY_SIZE
,
709 .type
= QEMU_OPT_SIZE
,
710 .help
= "Size of each entry in the L2 cache",
713 .name
= QCOW2_OPT_REFCOUNT_CACHE_SIZE
,
714 .type
= QEMU_OPT_SIZE
,
715 .help
= "Maximum refcount block cache size",
718 .name
= QCOW2_OPT_CACHE_CLEAN_INTERVAL
,
719 .type
= QEMU_OPT_NUMBER
,
720 .help
= "Clean unused cache entries after this time (in seconds)",
722 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.",
723 "ID of secret providing qcow2 AES key or LUKS passphrase"),
724 { /* end of list */ }
728 static const char *overlap_bool_option_names
[QCOW2_OL_MAX_BITNR
] = {
729 [QCOW2_OL_MAIN_HEADER_BITNR
] = QCOW2_OPT_OVERLAP_MAIN_HEADER
,
730 [QCOW2_OL_ACTIVE_L1_BITNR
] = QCOW2_OPT_OVERLAP_ACTIVE_L1
,
731 [QCOW2_OL_ACTIVE_L2_BITNR
] = QCOW2_OPT_OVERLAP_ACTIVE_L2
,
732 [QCOW2_OL_REFCOUNT_TABLE_BITNR
] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
,
733 [QCOW2_OL_REFCOUNT_BLOCK_BITNR
] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
,
734 [QCOW2_OL_SNAPSHOT_TABLE_BITNR
] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
,
735 [QCOW2_OL_INACTIVE_L1_BITNR
] = QCOW2_OPT_OVERLAP_INACTIVE_L1
,
736 [QCOW2_OL_INACTIVE_L2_BITNR
] = QCOW2_OPT_OVERLAP_INACTIVE_L2
,
737 [QCOW2_OL_BITMAP_DIRECTORY_BITNR
] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY
,
740 static void cache_clean_timer_cb(void *opaque
)
742 BlockDriverState
*bs
= opaque
;
743 BDRVQcow2State
*s
= bs
->opaque
;
744 qcow2_cache_clean_unused(s
->l2_table_cache
);
745 qcow2_cache_clean_unused(s
->refcount_block_cache
);
746 timer_mod(s
->cache_clean_timer
, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL
) +
747 (int64_t) s
->cache_clean_interval
* 1000);
750 static void cache_clean_timer_init(BlockDriverState
*bs
, AioContext
*context
)
752 BDRVQcow2State
*s
= bs
->opaque
;
753 if (s
->cache_clean_interval
> 0) {
754 s
->cache_clean_timer
= aio_timer_new(context
, QEMU_CLOCK_VIRTUAL
,
755 SCALE_MS
, cache_clean_timer_cb
,
757 timer_mod(s
->cache_clean_timer
, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL
) +
758 (int64_t) s
->cache_clean_interval
* 1000);
762 static void cache_clean_timer_del(BlockDriverState
*bs
)
764 BDRVQcow2State
*s
= bs
->opaque
;
765 if (s
->cache_clean_timer
) {
766 timer_del(s
->cache_clean_timer
);
767 timer_free(s
->cache_clean_timer
);
768 s
->cache_clean_timer
= NULL
;
772 static void qcow2_detach_aio_context(BlockDriverState
*bs
)
774 cache_clean_timer_del(bs
);
777 static void qcow2_attach_aio_context(BlockDriverState
*bs
,
778 AioContext
*new_context
)
780 cache_clean_timer_init(bs
, new_context
);
783 static void read_cache_sizes(BlockDriverState
*bs
, QemuOpts
*opts
,
784 uint64_t *l2_cache_size
,
785 uint64_t *l2_cache_entry_size
,
786 uint64_t *refcount_cache_size
, Error
**errp
)
788 BDRVQcow2State
*s
= bs
->opaque
;
789 uint64_t combined_cache_size
, l2_cache_max_setting
;
790 bool l2_cache_size_set
, refcount_cache_size_set
, combined_cache_size_set
;
791 bool l2_cache_entry_size_set
;
792 int min_refcount_cache
= MIN_REFCOUNT_CACHE_SIZE
* s
->cluster_size
;
793 uint64_t virtual_disk_size
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
794 uint64_t max_l2_cache
= virtual_disk_size
/ (s
->cluster_size
/ 8);
796 combined_cache_size_set
= qemu_opt_get(opts
, QCOW2_OPT_CACHE_SIZE
);
797 l2_cache_size_set
= qemu_opt_get(opts
, QCOW2_OPT_L2_CACHE_SIZE
);
798 refcount_cache_size_set
= qemu_opt_get(opts
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
);
799 l2_cache_entry_size_set
= qemu_opt_get(opts
, QCOW2_OPT_L2_CACHE_ENTRY_SIZE
);
801 combined_cache_size
= qemu_opt_get_size(opts
, QCOW2_OPT_CACHE_SIZE
, 0);
802 l2_cache_max_setting
= qemu_opt_get_size(opts
, QCOW2_OPT_L2_CACHE_SIZE
,
803 DEFAULT_L2_CACHE_MAX_SIZE
);
804 *refcount_cache_size
= qemu_opt_get_size(opts
,
805 QCOW2_OPT_REFCOUNT_CACHE_SIZE
, 0);
807 *l2_cache_entry_size
= qemu_opt_get_size(
808 opts
, QCOW2_OPT_L2_CACHE_ENTRY_SIZE
, s
->cluster_size
);
810 *l2_cache_size
= MIN(max_l2_cache
, l2_cache_max_setting
);
812 if (combined_cache_size_set
) {
813 if (l2_cache_size_set
&& refcount_cache_size_set
) {
814 error_setg(errp
, QCOW2_OPT_CACHE_SIZE
", " QCOW2_OPT_L2_CACHE_SIZE
815 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE
" may not be set "
818 } else if (l2_cache_size_set
&&
819 (l2_cache_max_setting
> combined_cache_size
)) {
820 error_setg(errp
, QCOW2_OPT_L2_CACHE_SIZE
" may not exceed "
821 QCOW2_OPT_CACHE_SIZE
);
823 } else if (*refcount_cache_size
> combined_cache_size
) {
824 error_setg(errp
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
" may not exceed "
825 QCOW2_OPT_CACHE_SIZE
);
829 if (l2_cache_size_set
) {
830 *refcount_cache_size
= combined_cache_size
- *l2_cache_size
;
831 } else if (refcount_cache_size_set
) {
832 *l2_cache_size
= combined_cache_size
- *refcount_cache_size
;
834 /* Assign as much memory as possible to the L2 cache, and
835 * use the remainder for the refcount cache */
836 if (combined_cache_size
>= max_l2_cache
+ min_refcount_cache
) {
837 *l2_cache_size
= max_l2_cache
;
838 *refcount_cache_size
= combined_cache_size
- *l2_cache_size
;
840 *refcount_cache_size
=
841 MIN(combined_cache_size
, min_refcount_cache
);
842 *l2_cache_size
= combined_cache_size
- *refcount_cache_size
;
848 * If the L2 cache is not enough to cover the whole disk then
849 * default to 4KB entries. Smaller entries reduce the cost of
850 * loads and evictions and increase I/O performance.
852 if (*l2_cache_size
< max_l2_cache
&& !l2_cache_entry_size_set
) {
853 *l2_cache_entry_size
= MIN(s
->cluster_size
, 4096);
856 /* l2_cache_size and refcount_cache_size are ensured to have at least
857 * their minimum values in qcow2_update_options_prepare() */
859 if (*l2_cache_entry_size
< (1 << MIN_CLUSTER_BITS
) ||
860 *l2_cache_entry_size
> s
->cluster_size
||
861 !is_power_of_2(*l2_cache_entry_size
)) {
862 error_setg(errp
, "L2 cache entry size must be a power of two "
863 "between %d and the cluster size (%d)",
864 1 << MIN_CLUSTER_BITS
, s
->cluster_size
);
869 typedef struct Qcow2ReopenState
{
870 Qcow2Cache
*l2_table_cache
;
871 Qcow2Cache
*refcount_block_cache
;
872 int l2_slice_size
; /* Number of entries in a slice of the L2 table */
873 bool use_lazy_refcounts
;
875 bool discard_passthrough
[QCOW2_DISCARD_MAX
];
876 uint64_t cache_clean_interval
;
877 QCryptoBlockOpenOptions
*crypto_opts
; /* Disk encryption runtime options */
880 static int qcow2_update_options_prepare(BlockDriverState
*bs
,
882 QDict
*options
, int flags
,
885 BDRVQcow2State
*s
= bs
->opaque
;
886 QemuOpts
*opts
= NULL
;
887 const char *opt_overlap_check
, *opt_overlap_check_template
;
888 int overlap_check_template
= 0;
889 uint64_t l2_cache_size
, l2_cache_entry_size
, refcount_cache_size
;
891 const char *encryptfmt
;
892 QDict
*encryptopts
= NULL
;
893 Error
*local_err
= NULL
;
896 qdict_extract_subqdict(options
, &encryptopts
, "encrypt.");
897 encryptfmt
= qdict_get_try_str(encryptopts
, "format");
899 opts
= qemu_opts_create(&qcow2_runtime_opts
, NULL
, 0, &error_abort
);
900 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
902 error_propagate(errp
, local_err
);
907 /* get L2 table/refcount block cache size from command line options */
908 read_cache_sizes(bs
, opts
, &l2_cache_size
, &l2_cache_entry_size
,
909 &refcount_cache_size
, &local_err
);
911 error_propagate(errp
, local_err
);
916 l2_cache_size
/= l2_cache_entry_size
;
917 if (l2_cache_size
< MIN_L2_CACHE_SIZE
) {
918 l2_cache_size
= MIN_L2_CACHE_SIZE
;
920 if (l2_cache_size
> INT_MAX
) {
921 error_setg(errp
, "L2 cache size too big");
926 refcount_cache_size
/= s
->cluster_size
;
927 if (refcount_cache_size
< MIN_REFCOUNT_CACHE_SIZE
) {
928 refcount_cache_size
= MIN_REFCOUNT_CACHE_SIZE
;
930 if (refcount_cache_size
> INT_MAX
) {
931 error_setg(errp
, "Refcount cache size too big");
936 /* alloc new L2 table/refcount block cache, flush old one */
937 if (s
->l2_table_cache
) {
938 ret
= qcow2_cache_flush(bs
, s
->l2_table_cache
);
940 error_setg_errno(errp
, -ret
, "Failed to flush the L2 table cache");
945 if (s
->refcount_block_cache
) {
946 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
948 error_setg_errno(errp
, -ret
,
949 "Failed to flush the refcount block cache");
954 r
->l2_slice_size
= l2_cache_entry_size
/ sizeof(uint64_t);
955 r
->l2_table_cache
= qcow2_cache_create(bs
, l2_cache_size
,
956 l2_cache_entry_size
);
957 r
->refcount_block_cache
= qcow2_cache_create(bs
, refcount_cache_size
,
959 if (r
->l2_table_cache
== NULL
|| r
->refcount_block_cache
== NULL
) {
960 error_setg(errp
, "Could not allocate metadata caches");
965 /* New interval for cache cleanup timer */
966 r
->cache_clean_interval
=
967 qemu_opt_get_number(opts
, QCOW2_OPT_CACHE_CLEAN_INTERVAL
,
968 DEFAULT_CACHE_CLEAN_INTERVAL
);
970 if (r
->cache_clean_interval
!= 0) {
971 error_setg(errp
, QCOW2_OPT_CACHE_CLEAN_INTERVAL
972 " not supported on this host");
977 if (r
->cache_clean_interval
> UINT_MAX
) {
978 error_setg(errp
, "Cache clean interval too big");
983 /* lazy-refcounts; flush if going from enabled to disabled */
984 r
->use_lazy_refcounts
= qemu_opt_get_bool(opts
, QCOW2_OPT_LAZY_REFCOUNTS
,
985 (s
->compatible_features
& QCOW2_COMPAT_LAZY_REFCOUNTS
));
986 if (r
->use_lazy_refcounts
&& s
->qcow_version
< 3) {
987 error_setg(errp
, "Lazy refcounts require a qcow2 image with at least "
988 "qemu 1.1 compatibility level");
993 if (s
->use_lazy_refcounts
&& !r
->use_lazy_refcounts
) {
994 ret
= qcow2_mark_clean(bs
);
996 error_setg_errno(errp
, -ret
, "Failed to disable lazy refcounts");
1001 /* Overlap check options */
1002 opt_overlap_check
= qemu_opt_get(opts
, QCOW2_OPT_OVERLAP
);
1003 opt_overlap_check_template
= qemu_opt_get(opts
, QCOW2_OPT_OVERLAP_TEMPLATE
);
1004 if (opt_overlap_check_template
&& opt_overlap_check
&&
1005 strcmp(opt_overlap_check_template
, opt_overlap_check
))
1007 error_setg(errp
, "Conflicting values for qcow2 options '"
1008 QCOW2_OPT_OVERLAP
"' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
1009 "' ('%s')", opt_overlap_check
, opt_overlap_check_template
);
1013 if (!opt_overlap_check
) {
1014 opt_overlap_check
= opt_overlap_check_template
?: "cached";
1017 if (!strcmp(opt_overlap_check
, "none")) {
1018 overlap_check_template
= 0;
1019 } else if (!strcmp(opt_overlap_check
, "constant")) {
1020 overlap_check_template
= QCOW2_OL_CONSTANT
;
1021 } else if (!strcmp(opt_overlap_check
, "cached")) {
1022 overlap_check_template
= QCOW2_OL_CACHED
;
1023 } else if (!strcmp(opt_overlap_check
, "all")) {
1024 overlap_check_template
= QCOW2_OL_ALL
;
1026 error_setg(errp
, "Unsupported value '%s' for qcow2 option "
1027 "'overlap-check'. Allowed are any of the following: "
1028 "none, constant, cached, all", opt_overlap_check
);
1033 r
->overlap_check
= 0;
1034 for (i
= 0; i
< QCOW2_OL_MAX_BITNR
; i
++) {
1035 /* overlap-check defines a template bitmask, but every flag may be
1036 * overwritten through the associated boolean option */
1038 qemu_opt_get_bool(opts
, overlap_bool_option_names
[i
],
1039 overlap_check_template
& (1 << i
)) << i
;
1042 r
->discard_passthrough
[QCOW2_DISCARD_NEVER
] = false;
1043 r
->discard_passthrough
[QCOW2_DISCARD_ALWAYS
] = true;
1044 r
->discard_passthrough
[QCOW2_DISCARD_REQUEST
] =
1045 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_REQUEST
,
1046 flags
& BDRV_O_UNMAP
);
1047 r
->discard_passthrough
[QCOW2_DISCARD_SNAPSHOT
] =
1048 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_SNAPSHOT
, true);
1049 r
->discard_passthrough
[QCOW2_DISCARD_OTHER
] =
1050 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_OTHER
, false);
1052 switch (s
->crypt_method_header
) {
1053 case QCOW_CRYPT_NONE
:
1055 error_setg(errp
, "No encryption in image header, but options "
1056 "specified format '%s'", encryptfmt
);
1062 case QCOW_CRYPT_AES
:
1063 if (encryptfmt
&& !g_str_equal(encryptfmt
, "aes")) {
1065 "Header reported 'aes' encryption format but "
1066 "options specify '%s'", encryptfmt
);
1070 qdict_put_str(encryptopts
, "format", "qcow");
1071 r
->crypto_opts
= block_crypto_open_opts_init(encryptopts
, errp
);
1074 case QCOW_CRYPT_LUKS
:
1075 if (encryptfmt
&& !g_str_equal(encryptfmt
, "luks")) {
1077 "Header reported 'luks' encryption format but "
1078 "options specify '%s'", encryptfmt
);
1082 qdict_put_str(encryptopts
, "format", "luks");
1083 r
->crypto_opts
= block_crypto_open_opts_init(encryptopts
, errp
);
1087 error_setg(errp
, "Unsupported encryption method %d",
1088 s
->crypt_method_header
);
1091 if (s
->crypt_method_header
!= QCOW_CRYPT_NONE
&& !r
->crypto_opts
) {
1098 qobject_unref(encryptopts
);
1099 qemu_opts_del(opts
);
1104 static void qcow2_update_options_commit(BlockDriverState
*bs
,
1105 Qcow2ReopenState
*r
)
1107 BDRVQcow2State
*s
= bs
->opaque
;
1110 if (s
->l2_table_cache
) {
1111 qcow2_cache_destroy(s
->l2_table_cache
);
1113 if (s
->refcount_block_cache
) {
1114 qcow2_cache_destroy(s
->refcount_block_cache
);
1116 s
->l2_table_cache
= r
->l2_table_cache
;
1117 s
->refcount_block_cache
= r
->refcount_block_cache
;
1118 s
->l2_slice_size
= r
->l2_slice_size
;
1120 s
->overlap_check
= r
->overlap_check
;
1121 s
->use_lazy_refcounts
= r
->use_lazy_refcounts
;
1123 for (i
= 0; i
< QCOW2_DISCARD_MAX
; i
++) {
1124 s
->discard_passthrough
[i
] = r
->discard_passthrough
[i
];
1127 if (s
->cache_clean_interval
!= r
->cache_clean_interval
) {
1128 cache_clean_timer_del(bs
);
1129 s
->cache_clean_interval
= r
->cache_clean_interval
;
1130 cache_clean_timer_init(bs
, bdrv_get_aio_context(bs
));
1133 qapi_free_QCryptoBlockOpenOptions(s
->crypto_opts
);
1134 s
->crypto_opts
= r
->crypto_opts
;
1137 static void qcow2_update_options_abort(BlockDriverState
*bs
,
1138 Qcow2ReopenState
*r
)
1140 if (r
->l2_table_cache
) {
1141 qcow2_cache_destroy(r
->l2_table_cache
);
1143 if (r
->refcount_block_cache
) {
1144 qcow2_cache_destroy(r
->refcount_block_cache
);
1146 qapi_free_QCryptoBlockOpenOptions(r
->crypto_opts
);
1149 static int qcow2_update_options(BlockDriverState
*bs
, QDict
*options
,
1150 int flags
, Error
**errp
)
1152 Qcow2ReopenState r
= {};
1155 ret
= qcow2_update_options_prepare(bs
, &r
, options
, flags
, errp
);
1157 qcow2_update_options_commit(bs
, &r
);
1159 qcow2_update_options_abort(bs
, &r
);
1165 /* Called with s->lock held. */
1166 static int coroutine_fn
qcow2_do_open(BlockDriverState
*bs
, QDict
*options
,
1167 int flags
, Error
**errp
)
1169 BDRVQcow2State
*s
= bs
->opaque
;
1170 unsigned int len
, i
;
1173 Error
*local_err
= NULL
;
1175 uint64_t l1_vm_state_index
;
1176 bool update_header
= false;
1178 ret
= bdrv_pread(bs
->file
, 0, &header
, sizeof(header
));
1180 error_setg_errno(errp
, -ret
, "Could not read qcow2 header");
1183 header
.magic
= be32_to_cpu(header
.magic
);
1184 header
.version
= be32_to_cpu(header
.version
);
1185 header
.backing_file_offset
= be64_to_cpu(header
.backing_file_offset
);
1186 header
.backing_file_size
= be32_to_cpu(header
.backing_file_size
);
1187 header
.size
= be64_to_cpu(header
.size
);
1188 header
.cluster_bits
= be32_to_cpu(header
.cluster_bits
);
1189 header
.crypt_method
= be32_to_cpu(header
.crypt_method
);
1190 header
.l1_table_offset
= be64_to_cpu(header
.l1_table_offset
);
1191 header
.l1_size
= be32_to_cpu(header
.l1_size
);
1192 header
.refcount_table_offset
= be64_to_cpu(header
.refcount_table_offset
);
1193 header
.refcount_table_clusters
=
1194 be32_to_cpu(header
.refcount_table_clusters
);
1195 header
.snapshots_offset
= be64_to_cpu(header
.snapshots_offset
);
1196 header
.nb_snapshots
= be32_to_cpu(header
.nb_snapshots
);
1198 if (header
.magic
!= QCOW_MAGIC
) {
1199 error_setg(errp
, "Image is not in qcow2 format");
1203 if (header
.version
< 2 || header
.version
> 3) {
1204 error_setg(errp
, "Unsupported qcow2 version %" PRIu32
, header
.version
);
1209 s
->qcow_version
= header
.version
;
1211 /* Initialise cluster size */
1212 if (header
.cluster_bits
< MIN_CLUSTER_BITS
||
1213 header
.cluster_bits
> MAX_CLUSTER_BITS
) {
1214 error_setg(errp
, "Unsupported cluster size: 2^%" PRIu32
,
1215 header
.cluster_bits
);
1220 s
->cluster_bits
= header
.cluster_bits
;
1221 s
->cluster_size
= 1 << s
->cluster_bits
;
1222 s
->cluster_sectors
= 1 << (s
->cluster_bits
- BDRV_SECTOR_BITS
);
1224 /* Initialise version 3 header fields */
1225 if (header
.version
== 2) {
1226 header
.incompatible_features
= 0;
1227 header
.compatible_features
= 0;
1228 header
.autoclear_features
= 0;
1229 header
.refcount_order
= 4;
1230 header
.header_length
= 72;
1232 header
.incompatible_features
=
1233 be64_to_cpu(header
.incompatible_features
);
1234 header
.compatible_features
= be64_to_cpu(header
.compatible_features
);
1235 header
.autoclear_features
= be64_to_cpu(header
.autoclear_features
);
1236 header
.refcount_order
= be32_to_cpu(header
.refcount_order
);
1237 header
.header_length
= be32_to_cpu(header
.header_length
);
1239 if (header
.header_length
< 104) {
1240 error_setg(errp
, "qcow2 header too short");
1246 if (header
.header_length
> s
->cluster_size
) {
1247 error_setg(errp
, "qcow2 header exceeds cluster size");
1252 if (header
.header_length
> sizeof(header
)) {
1253 s
->unknown_header_fields_size
= header
.header_length
- sizeof(header
);
1254 s
->unknown_header_fields
= g_malloc(s
->unknown_header_fields_size
);
1255 ret
= bdrv_pread(bs
->file
, sizeof(header
), s
->unknown_header_fields
,
1256 s
->unknown_header_fields_size
);
1258 error_setg_errno(errp
, -ret
, "Could not read unknown qcow2 header "
1264 if (header
.backing_file_offset
> s
->cluster_size
) {
1265 error_setg(errp
, "Invalid backing file offset");
1270 if (header
.backing_file_offset
) {
1271 ext_end
= header
.backing_file_offset
;
1273 ext_end
= 1 << header
.cluster_bits
;
1276 /* Handle feature bits */
1277 s
->incompatible_features
= header
.incompatible_features
;
1278 s
->compatible_features
= header
.compatible_features
;
1279 s
->autoclear_features
= header
.autoclear_features
;
1281 if (s
->incompatible_features
& ~QCOW2_INCOMPAT_MASK
) {
1282 void *feature_table
= NULL
;
1283 qcow2_read_extensions(bs
, header
.header_length
, ext_end
,
1284 &feature_table
, flags
, NULL
, NULL
);
1285 report_unsupported_feature(errp
, feature_table
,
1286 s
->incompatible_features
&
1287 ~QCOW2_INCOMPAT_MASK
);
1289 g_free(feature_table
);
1293 if (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
) {
1294 /* Corrupt images may not be written to unless they are being repaired
1296 if ((flags
& BDRV_O_RDWR
) && !(flags
& BDRV_O_CHECK
)) {
1297 error_setg(errp
, "qcow2: Image is corrupt; cannot be opened "
1304 /* Check support for various header values */
1305 if (header
.refcount_order
> 6) {
1306 error_setg(errp
, "Reference count entry width too large; may not "
1311 s
->refcount_order
= header
.refcount_order
;
1312 s
->refcount_bits
= 1 << s
->refcount_order
;
1313 s
->refcount_max
= UINT64_C(1) << (s
->refcount_bits
- 1);
1314 s
->refcount_max
+= s
->refcount_max
- 1;
1316 s
->crypt_method_header
= header
.crypt_method
;
1317 if (s
->crypt_method_header
) {
1318 if (bdrv_uses_whitelist() &&
1319 s
->crypt_method_header
== QCOW_CRYPT_AES
) {
1321 "Use of AES-CBC encrypted qcow2 images is no longer "
1322 "supported in system emulators");
1323 error_append_hint(errp
,
1324 "You can use 'qemu-img convert' to convert your "
1325 "image to an alternative supported format, such "
1326 "as unencrypted qcow2, or raw with the LUKS "
1327 "format instead.\n");
1332 if (s
->crypt_method_header
== QCOW_CRYPT_AES
) {
1333 s
->crypt_physical_offset
= false;
1335 /* Assuming LUKS and any future crypt methods we
1336 * add will all use physical offsets, due to the
1337 * fact that the alternative is insecure... */
1338 s
->crypt_physical_offset
= true;
1341 bs
->encrypted
= true;
1344 s
->l2_bits
= s
->cluster_bits
- 3; /* L2 is always one cluster */
1345 s
->l2_size
= 1 << s
->l2_bits
;
1346 /* 2^(s->refcount_order - 3) is the refcount width in bytes */
1347 s
->refcount_block_bits
= s
->cluster_bits
- (s
->refcount_order
- 3);
1348 s
->refcount_block_size
= 1 << s
->refcount_block_bits
;
1349 bs
->total_sectors
= header
.size
/ BDRV_SECTOR_SIZE
;
1350 s
->csize_shift
= (62 - (s
->cluster_bits
- 8));
1351 s
->csize_mask
= (1 << (s
->cluster_bits
- 8)) - 1;
1352 s
->cluster_offset_mask
= (1LL << s
->csize_shift
) - 1;
1354 s
->refcount_table_offset
= header
.refcount_table_offset
;
1355 s
->refcount_table_size
=
1356 header
.refcount_table_clusters
<< (s
->cluster_bits
- 3);
1358 if (header
.refcount_table_clusters
== 0 && !(flags
& BDRV_O_CHECK
)) {
1359 error_setg(errp
, "Image does not contain a reference count table");
1364 ret
= qcow2_validate_table(bs
, s
->refcount_table_offset
,
1365 header
.refcount_table_clusters
,
1366 s
->cluster_size
, QCOW_MAX_REFTABLE_SIZE
,
1367 "Reference count table", errp
);
1372 /* The total size in bytes of the snapshot table is checked in
1373 * qcow2_read_snapshots() because the size of each snapshot is
1374 * variable and we don't know it yet.
1375 * Here we only check the offset and number of snapshots. */
1376 ret
= qcow2_validate_table(bs
, header
.snapshots_offset
,
1377 header
.nb_snapshots
,
1378 sizeof(QCowSnapshotHeader
),
1379 sizeof(QCowSnapshotHeader
) * QCOW_MAX_SNAPSHOTS
,
1380 "Snapshot table", errp
);
1385 /* read the level 1 table */
1386 ret
= qcow2_validate_table(bs
, header
.l1_table_offset
,
1387 header
.l1_size
, sizeof(uint64_t),
1388 QCOW_MAX_L1_SIZE
, "Active L1 table", errp
);
1392 s
->l1_size
= header
.l1_size
;
1393 s
->l1_table_offset
= header
.l1_table_offset
;
1395 l1_vm_state_index
= size_to_l1(s
, header
.size
);
1396 if (l1_vm_state_index
> INT_MAX
) {
1397 error_setg(errp
, "Image is too big");
1401 s
->l1_vm_state_index
= l1_vm_state_index
;
1403 /* the L1 table must contain at least enough entries to put
1404 header.size bytes */
1405 if (s
->l1_size
< s
->l1_vm_state_index
) {
1406 error_setg(errp
, "L1 table is too small");
1411 if (s
->l1_size
> 0) {
1412 s
->l1_table
= qemu_try_blockalign(bs
->file
->bs
,
1413 ROUND_UP(s
->l1_size
* sizeof(uint64_t), 512));
1414 if (s
->l1_table
== NULL
) {
1415 error_setg(errp
, "Could not allocate L1 table");
1419 ret
= bdrv_pread(bs
->file
, s
->l1_table_offset
, s
->l1_table
,
1420 s
->l1_size
* sizeof(uint64_t));
1422 error_setg_errno(errp
, -ret
, "Could not read L1 table");
1425 for(i
= 0;i
< s
->l1_size
; i
++) {
1426 s
->l1_table
[i
] = be64_to_cpu(s
->l1_table
[i
]);
1430 /* Parse driver-specific options */
1431 ret
= qcow2_update_options(bs
, options
, flags
, errp
);
1438 ret
= qcow2_refcount_init(bs
);
1440 error_setg_errno(errp
, -ret
, "Could not initialize refcount handling");
1444 QLIST_INIT(&s
->cluster_allocs
);
1445 QTAILQ_INIT(&s
->discards
);
1447 /* read qcow2 extensions */
1448 if (qcow2_read_extensions(bs
, header
.header_length
, ext_end
, NULL
,
1449 flags
, &update_header
, &local_err
)) {
1450 error_propagate(errp
, local_err
);
1455 /* qcow2_read_extension may have set up the crypto context
1456 * if the crypt method needs a header region, some methods
1457 * don't need header extensions, so must check here
1459 if (s
->crypt_method_header
&& !s
->crypto
) {
1460 if (s
->crypt_method_header
== QCOW_CRYPT_AES
) {
1461 unsigned int cflags
= 0;
1462 if (flags
& BDRV_O_NO_IO
) {
1463 cflags
|= QCRYPTO_BLOCK_OPEN_NO_IO
;
1465 s
->crypto
= qcrypto_block_open(s
->crypto_opts
, "encrypt.",
1466 NULL
, NULL
, cflags
, 1, errp
);
1471 } else if (!(flags
& BDRV_O_NO_IO
)) {
1472 error_setg(errp
, "Missing CRYPTO header for crypt method %d",
1473 s
->crypt_method_header
);
1479 /* read the backing file name */
1480 if (header
.backing_file_offset
!= 0) {
1481 len
= header
.backing_file_size
;
1482 if (len
> MIN(1023, s
->cluster_size
- header
.backing_file_offset
) ||
1483 len
>= sizeof(bs
->backing_file
)) {
1484 error_setg(errp
, "Backing file name too long");
1488 ret
= bdrv_pread(bs
->file
, header
.backing_file_offset
,
1489 bs
->auto_backing_file
, len
);
1491 error_setg_errno(errp
, -ret
, "Could not read backing file name");
1494 bs
->auto_backing_file
[len
] = '\0';
1495 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
),
1496 bs
->auto_backing_file
);
1497 s
->image_backing_file
= g_strdup(bs
->auto_backing_file
);
1500 /* Internal snapshots */
1501 s
->snapshots_offset
= header
.snapshots_offset
;
1502 s
->nb_snapshots
= header
.nb_snapshots
;
1504 ret
= qcow2_read_snapshots(bs
);
1506 error_setg_errno(errp
, -ret
, "Could not read snapshots");
1510 /* Clear unknown autoclear feature bits */
1511 update_header
|= s
->autoclear_features
& ~QCOW2_AUTOCLEAR_MASK
;
1513 update_header
&& !bs
->read_only
&& !(flags
& BDRV_O_INACTIVE
);
1514 if (update_header
) {
1515 s
->autoclear_features
&= QCOW2_AUTOCLEAR_MASK
;
1518 /* == Handle persistent dirty bitmaps ==
1520 * We want load dirty bitmaps in three cases:
1522 * 1. Normal open of the disk in active mode, not related to invalidation
1525 * 2. Invalidation of the target vm after pre-copy phase of migration, if
1526 * bitmaps are _not_ migrating through migration channel, i.e.
1527 * 'dirty-bitmaps' capability is disabled.
1529 * 3. Invalidation of source vm after failed or canceled migration.
1530 * This is a very interesting case. There are two possible types of
1533 * A. Stored on inactivation and removed. They should be loaded from the
1536 * B. Not stored: not-persistent bitmaps and bitmaps, migrated through
1537 * the migration channel (with dirty-bitmaps capability).
1539 * On the other hand, there are two possible sub-cases:
1541 * 3.1 disk was changed by somebody else while were inactive. In this
1542 * case all in-RAM dirty bitmaps (both persistent and not) are
1543 * definitely invalid. And we don't have any method to determine
1546 * Simple and safe thing is to just drop all the bitmaps of type B on
1547 * inactivation. But in this case we lose bitmaps in valid 4.2 case.
1549 * On the other hand, resuming source vm, if disk was already changed
1550 * is a bad thing anyway: not only bitmaps, the whole vm state is
1551 * out of sync with disk.
1553 * This means, that user or management tool, who for some reason
1554 * decided to resume source vm, after disk was already changed by
1555 * target vm, should at least drop all dirty bitmaps by hand.
1557 * So, we can ignore this case for now, but TODO: "generation"
1558 * extension for qcow2, to determine, that image was changed after
1559 * last inactivation. And if it is changed, we will drop (or at least
1560 * mark as 'invalid' all the bitmaps of type B, both persistent
1563 * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved
1564 * to disk ('dirty-bitmaps' capability disabled), or not saved
1565 * ('dirty-bitmaps' capability enabled), but we don't need to care
1566 * of: let's load bitmaps as always: stored bitmaps will be loaded,
1567 * and not stored has flag IN_USE=1 in the image and will be skipped
1570 * One remaining possible case when we don't want load bitmaps:
1572 * 4. Open disk in inactive mode in target vm (bitmaps are migrating or
1573 * will be loaded on invalidation, no needs try loading them before)
1576 if (!(bdrv_get_flags(bs
) & BDRV_O_INACTIVE
)) {
1577 /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */
1578 bool header_updated
= qcow2_load_dirty_bitmaps(bs
, &local_err
);
1580 update_header
= update_header
&& !header_updated
;
1582 if (local_err
!= NULL
) {
1583 error_propagate(errp
, local_err
);
1588 if (update_header
) {
1589 ret
= qcow2_update_header(bs
);
1591 error_setg_errno(errp
, -ret
, "Could not update qcow2 header");
1596 bs
->supported_zero_flags
= header
.version
>= 3 ? BDRV_REQ_MAY_UNMAP
: 0;
1598 /* Repair image if dirty */
1599 if (!(flags
& (BDRV_O_CHECK
| BDRV_O_INACTIVE
)) && !bs
->read_only
&&
1600 (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
)) {
1601 BdrvCheckResult result
= {0};
1603 ret
= qcow2_co_check_locked(bs
, &result
,
1604 BDRV_FIX_ERRORS
| BDRV_FIX_LEAKS
);
1605 if (ret
< 0 || result
.check_errors
) {
1609 error_setg_errno(errp
, -ret
, "Could not repair dirty image");
1616 BdrvCheckResult result
= {0};
1617 qcow2_check_refcounts(bs
, &result
, 0);
1621 qemu_co_queue_init(&s
->compress_wait_queue
);
1626 g_free(s
->unknown_header_fields
);
1627 cleanup_unknown_header_ext(bs
);
1628 qcow2_free_snapshots(bs
);
1629 qcow2_refcount_close(bs
);
1630 qemu_vfree(s
->l1_table
);
1631 /* else pre-write overlap checks in cache_destroy may crash */
1633 cache_clean_timer_del(bs
);
1634 if (s
->l2_table_cache
) {
1635 qcow2_cache_destroy(s
->l2_table_cache
);
1637 if (s
->refcount_block_cache
) {
1638 qcow2_cache_destroy(s
->refcount_block_cache
);
1640 qcrypto_block_free(s
->crypto
);
1641 qapi_free_QCryptoBlockOpenOptions(s
->crypto_opts
);
1645 typedef struct QCow2OpenCo
{
1646 BlockDriverState
*bs
;
1653 static void coroutine_fn
qcow2_open_entry(void *opaque
)
1655 QCow2OpenCo
*qoc
= opaque
;
1656 BDRVQcow2State
*s
= qoc
->bs
->opaque
;
1658 qemu_co_mutex_lock(&s
->lock
);
1659 qoc
->ret
= qcow2_do_open(qoc
->bs
, qoc
->options
, qoc
->flags
, qoc
->errp
);
1660 qemu_co_mutex_unlock(&s
->lock
);
1663 static int qcow2_open(BlockDriverState
*bs
, QDict
*options
, int flags
,
1666 BDRVQcow2State
*s
= bs
->opaque
;
1675 bs
->file
= bdrv_open_child(NULL
, options
, "file", bs
, &child_file
,
1681 /* Initialise locks */
1682 qemu_co_mutex_init(&s
->lock
);
1684 if (qemu_in_coroutine()) {
1685 /* From bdrv_co_create. */
1686 qcow2_open_entry(&qoc
);
1688 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
1689 qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry
, &qoc
));
1690 BDRV_POLL_WHILE(bs
, qoc
.ret
== -EINPROGRESS
);
1695 static void qcow2_refresh_limits(BlockDriverState
*bs
, Error
**errp
)
1697 BDRVQcow2State
*s
= bs
->opaque
;
1699 if (bs
->encrypted
) {
1700 /* Encryption works on a sector granularity */
1701 bs
->bl
.request_alignment
= qcrypto_block_get_sector_size(s
->crypto
);
1703 bs
->bl
.pwrite_zeroes_alignment
= s
->cluster_size
;
1704 bs
->bl
.pdiscard_alignment
= s
->cluster_size
;
1707 static int qcow2_reopen_prepare(BDRVReopenState
*state
,
1708 BlockReopenQueue
*queue
, Error
**errp
)
1710 Qcow2ReopenState
*r
;
1713 r
= g_new0(Qcow2ReopenState
, 1);
1716 ret
= qcow2_update_options_prepare(state
->bs
, r
, state
->options
,
1717 state
->flags
, errp
);
1722 /* We need to write out any unwritten data if we reopen read-only. */
1723 if ((state
->flags
& BDRV_O_RDWR
) == 0) {
1724 ret
= qcow2_reopen_bitmaps_ro(state
->bs
, errp
);
1729 ret
= bdrv_flush(state
->bs
);
1734 ret
= qcow2_mark_clean(state
->bs
);
1743 qcow2_update_options_abort(state
->bs
, r
);
1748 static void qcow2_reopen_commit(BDRVReopenState
*state
)
1750 qcow2_update_options_commit(state
->bs
, state
->opaque
);
1751 g_free(state
->opaque
);
1754 static void qcow2_reopen_abort(BDRVReopenState
*state
)
1756 qcow2_update_options_abort(state
->bs
, state
->opaque
);
1757 g_free(state
->opaque
);
1760 static void qcow2_join_options(QDict
*options
, QDict
*old_options
)
1762 bool has_new_overlap_template
=
1763 qdict_haskey(options
, QCOW2_OPT_OVERLAP
) ||
1764 qdict_haskey(options
, QCOW2_OPT_OVERLAP_TEMPLATE
);
1765 bool has_new_total_cache_size
=
1766 qdict_haskey(options
, QCOW2_OPT_CACHE_SIZE
);
1767 bool has_all_cache_options
;
1769 /* New overlap template overrides all old overlap options */
1770 if (has_new_overlap_template
) {
1771 qdict_del(old_options
, QCOW2_OPT_OVERLAP
);
1772 qdict_del(old_options
, QCOW2_OPT_OVERLAP_TEMPLATE
);
1773 qdict_del(old_options
, QCOW2_OPT_OVERLAP_MAIN_HEADER
);
1774 qdict_del(old_options
, QCOW2_OPT_OVERLAP_ACTIVE_L1
);
1775 qdict_del(old_options
, QCOW2_OPT_OVERLAP_ACTIVE_L2
);
1776 qdict_del(old_options
, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
);
1777 qdict_del(old_options
, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
);
1778 qdict_del(old_options
, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
);
1779 qdict_del(old_options
, QCOW2_OPT_OVERLAP_INACTIVE_L1
);
1780 qdict_del(old_options
, QCOW2_OPT_OVERLAP_INACTIVE_L2
);
1783 /* New total cache size overrides all old options */
1784 if (qdict_haskey(options
, QCOW2_OPT_CACHE_SIZE
)) {
1785 qdict_del(old_options
, QCOW2_OPT_L2_CACHE_SIZE
);
1786 qdict_del(old_options
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
);
1789 qdict_join(options
, old_options
, false);
1792 * If after merging all cache size options are set, an old total size is
1793 * overwritten. Do keep all options, however, if all three are new. The
1794 * resulting error message is what we want to happen.
1796 has_all_cache_options
=
1797 qdict_haskey(options
, QCOW2_OPT_CACHE_SIZE
) ||
1798 qdict_haskey(options
, QCOW2_OPT_L2_CACHE_SIZE
) ||
1799 qdict_haskey(options
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
);
1801 if (has_all_cache_options
&& !has_new_total_cache_size
) {
1802 qdict_del(options
, QCOW2_OPT_CACHE_SIZE
);
1806 static int coroutine_fn
qcow2_co_block_status(BlockDriverState
*bs
,
1808 int64_t offset
, int64_t count
,
1809 int64_t *pnum
, int64_t *map
,
1810 BlockDriverState
**file
)
1812 BDRVQcow2State
*s
= bs
->opaque
;
1813 uint64_t cluster_offset
;
1814 int index_in_cluster
, ret
;
1818 bytes
= MIN(INT_MAX
, count
);
1819 qemu_co_mutex_lock(&s
->lock
);
1820 ret
= qcow2_get_cluster_offset(bs
, offset
, &bytes
, &cluster_offset
);
1821 qemu_co_mutex_unlock(&s
->lock
);
1828 if (cluster_offset
!= 0 && ret
!= QCOW2_CLUSTER_COMPRESSED
&&
1830 index_in_cluster
= offset
& (s
->cluster_size
- 1);
1831 *map
= cluster_offset
| index_in_cluster
;
1832 *file
= bs
->file
->bs
;
1833 status
|= BDRV_BLOCK_OFFSET_VALID
;
1835 if (ret
== QCOW2_CLUSTER_ZERO_PLAIN
|| ret
== QCOW2_CLUSTER_ZERO_ALLOC
) {
1836 status
|= BDRV_BLOCK_ZERO
;
1837 } else if (ret
!= QCOW2_CLUSTER_UNALLOCATED
) {
1838 status
|= BDRV_BLOCK_DATA
;
1843 static coroutine_fn
int qcow2_handle_l2meta(BlockDriverState
*bs
,
1844 QCowL2Meta
**pl2meta
,
1848 QCowL2Meta
*l2meta
= *pl2meta
;
1850 while (l2meta
!= NULL
) {
1854 ret
= qcow2_alloc_cluster_link_l2(bs
, l2meta
);
1859 qcow2_alloc_cluster_abort(bs
, l2meta
);
1862 /* Take the request off the list of running requests */
1863 if (l2meta
->nb_clusters
!= 0) {
1864 QLIST_REMOVE(l2meta
, next_in_flight
);
1867 qemu_co_queue_restart_all(&l2meta
->dependent_requests
);
1869 next
= l2meta
->next
;
1878 static coroutine_fn
int qcow2_co_preadv(BlockDriverState
*bs
, uint64_t offset
,
1879 uint64_t bytes
, QEMUIOVector
*qiov
,
1882 BDRVQcow2State
*s
= bs
->opaque
;
1883 int offset_in_cluster
;
1885 unsigned int cur_bytes
; /* number of bytes in current iteration */
1886 uint64_t cluster_offset
= 0;
1887 uint64_t bytes_done
= 0;
1888 QEMUIOVector hd_qiov
;
1889 uint8_t *cluster_data
= NULL
;
1891 qemu_iovec_init(&hd_qiov
, qiov
->niov
);
1893 qemu_co_mutex_lock(&s
->lock
);
1895 while (bytes
!= 0) {
1897 /* prepare next request */
1898 cur_bytes
= MIN(bytes
, INT_MAX
);
1900 cur_bytes
= MIN(cur_bytes
,
1901 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
1904 ret
= qcow2_get_cluster_offset(bs
, offset
, &cur_bytes
, &cluster_offset
);
1909 offset_in_cluster
= offset_into_cluster(s
, offset
);
1911 qemu_iovec_reset(&hd_qiov
);
1912 qemu_iovec_concat(&hd_qiov
, qiov
, bytes_done
, cur_bytes
);
1915 case QCOW2_CLUSTER_UNALLOCATED
:
1918 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_BACKING_AIO
);
1919 qemu_co_mutex_unlock(&s
->lock
);
1920 ret
= bdrv_co_preadv(bs
->backing
, offset
, cur_bytes
,
1922 qemu_co_mutex_lock(&s
->lock
);
1927 /* Note: in this case, no need to wait */
1928 qemu_iovec_memset(&hd_qiov
, 0, 0, cur_bytes
);
1932 case QCOW2_CLUSTER_ZERO_PLAIN
:
1933 case QCOW2_CLUSTER_ZERO_ALLOC
:
1934 qemu_iovec_memset(&hd_qiov
, 0, 0, cur_bytes
);
1937 case QCOW2_CLUSTER_COMPRESSED
:
1938 qemu_co_mutex_unlock(&s
->lock
);
1939 ret
= qcow2_co_preadv_compressed(bs
, cluster_offset
,
1942 qemu_co_mutex_lock(&s
->lock
);
1949 case QCOW2_CLUSTER_NORMAL
:
1950 if ((cluster_offset
& 511) != 0) {
1955 if (bs
->encrypted
) {
1959 * For encrypted images, read everything into a temporary
1960 * contiguous buffer on which the AES functions can work.
1962 if (!cluster_data
) {
1964 qemu_try_blockalign(bs
->file
->bs
,
1965 QCOW_MAX_CRYPT_CLUSTERS
1967 if (cluster_data
== NULL
) {
1973 assert(cur_bytes
<= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
1974 qemu_iovec_reset(&hd_qiov
);
1975 qemu_iovec_add(&hd_qiov
, cluster_data
, cur_bytes
);
1978 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_AIO
);
1979 qemu_co_mutex_unlock(&s
->lock
);
1980 ret
= bdrv_co_preadv(bs
->file
,
1981 cluster_offset
+ offset_in_cluster
,
1982 cur_bytes
, &hd_qiov
, 0);
1983 qemu_co_mutex_lock(&s
->lock
);
1987 if (bs
->encrypted
) {
1989 assert((offset
& (BDRV_SECTOR_SIZE
- 1)) == 0);
1990 assert((cur_bytes
& (BDRV_SECTOR_SIZE
- 1)) == 0);
1991 if (qcrypto_block_decrypt(s
->crypto
,
1992 (s
->crypt_physical_offset
?
1993 cluster_offset
+ offset_in_cluster
:
2001 qemu_iovec_from_buf(qiov
, bytes_done
, cluster_data
, cur_bytes
);
2006 g_assert_not_reached();
2012 offset
+= cur_bytes
;
2013 bytes_done
+= cur_bytes
;
2018 qemu_co_mutex_unlock(&s
->lock
);
2020 qemu_iovec_destroy(&hd_qiov
);
2021 qemu_vfree(cluster_data
);
2026 /* Check if it's possible to merge a write request with the writing of
2027 * the data from the COW regions */
2028 static bool merge_cow(uint64_t offset
, unsigned bytes
,
2029 QEMUIOVector
*hd_qiov
, QCowL2Meta
*l2meta
)
2033 for (m
= l2meta
; m
!= NULL
; m
= m
->next
) {
2034 /* If both COW regions are empty then there's nothing to merge */
2035 if (m
->cow_start
.nb_bytes
== 0 && m
->cow_end
.nb_bytes
== 0) {
2039 /* The data (middle) region must be immediately after the
2041 if (l2meta_cow_start(m
) + m
->cow_start
.nb_bytes
!= offset
) {
2045 /* The end region must be immediately after the data (middle)
2047 if (m
->offset
+ m
->cow_end
.offset
!= offset
+ bytes
) {
2051 /* Make sure that adding both COW regions to the QEMUIOVector
2052 * does not exceed IOV_MAX */
2053 if (hd_qiov
->niov
> IOV_MAX
- 2) {
2057 m
->data_qiov
= hd_qiov
;
2064 static coroutine_fn
int qcow2_co_pwritev(BlockDriverState
*bs
, uint64_t offset
,
2065 uint64_t bytes
, QEMUIOVector
*qiov
,
2068 BDRVQcow2State
*s
= bs
->opaque
;
2069 int offset_in_cluster
;
2071 unsigned int cur_bytes
; /* number of sectors in current iteration */
2072 uint64_t cluster_offset
;
2073 QEMUIOVector hd_qiov
;
2074 uint64_t bytes_done
= 0;
2075 uint8_t *cluster_data
= NULL
;
2076 QCowL2Meta
*l2meta
= NULL
;
2078 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset
, bytes
);
2080 qemu_iovec_init(&hd_qiov
, qiov
->niov
);
2082 qemu_co_mutex_lock(&s
->lock
);
2084 while (bytes
!= 0) {
2088 trace_qcow2_writev_start_part(qemu_coroutine_self());
2089 offset_in_cluster
= offset_into_cluster(s
, offset
);
2090 cur_bytes
= MIN(bytes
, INT_MAX
);
2091 if (bs
->encrypted
) {
2092 cur_bytes
= MIN(cur_bytes
,
2093 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
2094 - offset_in_cluster
);
2097 ret
= qcow2_alloc_cluster_offset(bs
, offset
, &cur_bytes
,
2098 &cluster_offset
, &l2meta
);
2103 assert((cluster_offset
& 511) == 0);
2105 qemu_iovec_reset(&hd_qiov
);
2106 qemu_iovec_concat(&hd_qiov
, qiov
, bytes_done
, cur_bytes
);
2108 if (bs
->encrypted
) {
2110 if (!cluster_data
) {
2111 cluster_data
= qemu_try_blockalign(bs
->file
->bs
,
2112 QCOW_MAX_CRYPT_CLUSTERS
2114 if (cluster_data
== NULL
) {
2120 assert(hd_qiov
.size
<=
2121 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
2122 qemu_iovec_to_buf(&hd_qiov
, 0, cluster_data
, hd_qiov
.size
);
2124 if (qcrypto_block_encrypt(s
->crypto
,
2125 (s
->crypt_physical_offset
?
2126 cluster_offset
+ offset_in_cluster
:
2129 cur_bytes
, NULL
) < 0) {
2134 qemu_iovec_reset(&hd_qiov
);
2135 qemu_iovec_add(&hd_qiov
, cluster_data
, cur_bytes
);
2138 ret
= qcow2_pre_write_overlap_check(bs
, 0,
2139 cluster_offset
+ offset_in_cluster
, cur_bytes
);
2144 /* If we need to do COW, check if it's possible to merge the
2145 * writing of the guest data together with that of the COW regions.
2146 * If it's not possible (or not necessary) then write the
2147 * guest data now. */
2148 if (!merge_cow(offset
, cur_bytes
, &hd_qiov
, l2meta
)) {
2149 qemu_co_mutex_unlock(&s
->lock
);
2150 BLKDBG_EVENT(bs
->file
, BLKDBG_WRITE_AIO
);
2151 trace_qcow2_writev_data(qemu_coroutine_self(),
2152 cluster_offset
+ offset_in_cluster
);
2153 ret
= bdrv_co_pwritev(bs
->file
,
2154 cluster_offset
+ offset_in_cluster
,
2155 cur_bytes
, &hd_qiov
, 0);
2156 qemu_co_mutex_lock(&s
->lock
);
2162 ret
= qcow2_handle_l2meta(bs
, &l2meta
, true);
2168 offset
+= cur_bytes
;
2169 bytes_done
+= cur_bytes
;
2170 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes
);
2175 qcow2_handle_l2meta(bs
, &l2meta
, false);
2177 qemu_co_mutex_unlock(&s
->lock
);
2179 qemu_iovec_destroy(&hd_qiov
);
2180 qemu_vfree(cluster_data
);
2181 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret
);
2186 static int qcow2_inactivate(BlockDriverState
*bs
)
2188 BDRVQcow2State
*s
= bs
->opaque
;
2189 int ret
, result
= 0;
2190 Error
*local_err
= NULL
;
2192 qcow2_store_persistent_dirty_bitmaps(bs
, &local_err
);
2193 if (local_err
!= NULL
) {
2195 error_reportf_err(local_err
, "Lost persistent bitmaps during "
2196 "inactivation of node '%s': ",
2197 bdrv_get_device_or_node_name(bs
));
2200 ret
= qcow2_cache_flush(bs
, s
->l2_table_cache
);
2203 error_report("Failed to flush the L2 table cache: %s",
2207 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
2210 error_report("Failed to flush the refcount block cache: %s",
2215 qcow2_mark_clean(bs
);
2221 static void qcow2_close(BlockDriverState
*bs
)
2223 BDRVQcow2State
*s
= bs
->opaque
;
2224 qemu_vfree(s
->l1_table
);
2225 /* else pre-write overlap checks in cache_destroy may crash */
2228 if (!(s
->flags
& BDRV_O_INACTIVE
)) {
2229 qcow2_inactivate(bs
);
2232 cache_clean_timer_del(bs
);
2233 qcow2_cache_destroy(s
->l2_table_cache
);
2234 qcow2_cache_destroy(s
->refcount_block_cache
);
2236 qcrypto_block_free(s
->crypto
);
2239 g_free(s
->unknown_header_fields
);
2240 cleanup_unknown_header_ext(bs
);
2242 g_free(s
->image_backing_file
);
2243 g_free(s
->image_backing_format
);
2245 qcow2_refcount_close(bs
);
2246 qcow2_free_snapshots(bs
);
2249 static void coroutine_fn
qcow2_co_invalidate_cache(BlockDriverState
*bs
,
2252 BDRVQcow2State
*s
= bs
->opaque
;
2253 int flags
= s
->flags
;
2254 QCryptoBlock
*crypto
= NULL
;
2256 Error
*local_err
= NULL
;
2260 * Backing files are read-only which makes all of their metadata immutable,
2261 * that means we don't have to worry about reopening them here.
2269 memset(s
, 0, sizeof(BDRVQcow2State
));
2270 options
= qdict_clone_shallow(bs
->options
);
2272 flags
&= ~BDRV_O_INACTIVE
;
2273 qemu_co_mutex_lock(&s
->lock
);
2274 ret
= qcow2_do_open(bs
, options
, flags
, &local_err
);
2275 qemu_co_mutex_unlock(&s
->lock
);
2276 qobject_unref(options
);
2278 error_propagate_prepend(errp
, local_err
,
2279 "Could not reopen qcow2 layer: ");
2282 } else if (ret
< 0) {
2283 error_setg_errno(errp
, -ret
, "Could not reopen qcow2 layer");
2291 static size_t header_ext_add(char *buf
, uint32_t magic
, const void *s
,
2292 size_t len
, size_t buflen
)
2294 QCowExtension
*ext_backing_fmt
= (QCowExtension
*) buf
;
2295 size_t ext_len
= sizeof(QCowExtension
) + ((len
+ 7) & ~7);
2297 if (buflen
< ext_len
) {
2301 *ext_backing_fmt
= (QCowExtension
) {
2302 .magic
= cpu_to_be32(magic
),
2303 .len
= cpu_to_be32(len
),
2307 memcpy(buf
+ sizeof(QCowExtension
), s
, len
);
2314 * Updates the qcow2 header, including the variable length parts of it, i.e.
2315 * the backing file name and all extensions. qcow2 was not designed to allow
2316 * such changes, so if we run out of space (we can only use the first cluster)
2317 * this function may fail.
2319 * Returns 0 on success, -errno in error cases.
2321 int qcow2_update_header(BlockDriverState
*bs
)
2323 BDRVQcow2State
*s
= bs
->opaque
;
2326 size_t buflen
= s
->cluster_size
;
2328 uint64_t total_size
;
2329 uint32_t refcount_table_clusters
;
2330 size_t header_length
;
2331 Qcow2UnknownHeaderExtension
*uext
;
2333 buf
= qemu_blockalign(bs
, buflen
);
2335 /* Header structure */
2336 header
= (QCowHeader
*) buf
;
2338 if (buflen
< sizeof(*header
)) {
2343 header_length
= sizeof(*header
) + s
->unknown_header_fields_size
;
2344 total_size
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
2345 refcount_table_clusters
= s
->refcount_table_size
>> (s
->cluster_bits
- 3);
2347 *header
= (QCowHeader
) {
2348 /* Version 2 fields */
2349 .magic
= cpu_to_be32(QCOW_MAGIC
),
2350 .version
= cpu_to_be32(s
->qcow_version
),
2351 .backing_file_offset
= 0,
2352 .backing_file_size
= 0,
2353 .cluster_bits
= cpu_to_be32(s
->cluster_bits
),
2354 .size
= cpu_to_be64(total_size
),
2355 .crypt_method
= cpu_to_be32(s
->crypt_method_header
),
2356 .l1_size
= cpu_to_be32(s
->l1_size
),
2357 .l1_table_offset
= cpu_to_be64(s
->l1_table_offset
),
2358 .refcount_table_offset
= cpu_to_be64(s
->refcount_table_offset
),
2359 .refcount_table_clusters
= cpu_to_be32(refcount_table_clusters
),
2360 .nb_snapshots
= cpu_to_be32(s
->nb_snapshots
),
2361 .snapshots_offset
= cpu_to_be64(s
->snapshots_offset
),
2363 /* Version 3 fields */
2364 .incompatible_features
= cpu_to_be64(s
->incompatible_features
),
2365 .compatible_features
= cpu_to_be64(s
->compatible_features
),
2366 .autoclear_features
= cpu_to_be64(s
->autoclear_features
),
2367 .refcount_order
= cpu_to_be32(s
->refcount_order
),
2368 .header_length
= cpu_to_be32(header_length
),
2371 /* For older versions, write a shorter header */
2372 switch (s
->qcow_version
) {
2374 ret
= offsetof(QCowHeader
, incompatible_features
);
2377 ret
= sizeof(*header
);
2386 memset(buf
, 0, buflen
);
2388 /* Preserve any unknown field in the header */
2389 if (s
->unknown_header_fields_size
) {
2390 if (buflen
< s
->unknown_header_fields_size
) {
2395 memcpy(buf
, s
->unknown_header_fields
, s
->unknown_header_fields_size
);
2396 buf
+= s
->unknown_header_fields_size
;
2397 buflen
-= s
->unknown_header_fields_size
;
2400 /* Backing file format header extension */
2401 if (s
->image_backing_format
) {
2402 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_BACKING_FORMAT
,
2403 s
->image_backing_format
,
2404 strlen(s
->image_backing_format
),
2414 /* Full disk encryption header pointer extension */
2415 if (s
->crypto_header
.offset
!= 0) {
2416 s
->crypto_header
.offset
= cpu_to_be64(s
->crypto_header
.offset
);
2417 s
->crypto_header
.length
= cpu_to_be64(s
->crypto_header
.length
);
2418 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_CRYPTO_HEADER
,
2419 &s
->crypto_header
, sizeof(s
->crypto_header
),
2421 s
->crypto_header
.offset
= be64_to_cpu(s
->crypto_header
.offset
);
2422 s
->crypto_header
.length
= be64_to_cpu(s
->crypto_header
.length
);
2431 if (s
->qcow_version
>= 3) {
2432 Qcow2Feature features
[] = {
2434 .type
= QCOW2_FEAT_TYPE_INCOMPATIBLE
,
2435 .bit
= QCOW2_INCOMPAT_DIRTY_BITNR
,
2436 .name
= "dirty bit",
2439 .type
= QCOW2_FEAT_TYPE_INCOMPATIBLE
,
2440 .bit
= QCOW2_INCOMPAT_CORRUPT_BITNR
,
2441 .name
= "corrupt bit",
2444 .type
= QCOW2_FEAT_TYPE_COMPATIBLE
,
2445 .bit
= QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR
,
2446 .name
= "lazy refcounts",
2450 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_FEATURE_TABLE
,
2451 features
, sizeof(features
), buflen
);
2459 /* Bitmap extension */
2460 if (s
->nb_bitmaps
> 0) {
2461 Qcow2BitmapHeaderExt bitmaps_header
= {
2462 .nb_bitmaps
= cpu_to_be32(s
->nb_bitmaps
),
2463 .bitmap_directory_size
=
2464 cpu_to_be64(s
->bitmap_directory_size
),
2465 .bitmap_directory_offset
=
2466 cpu_to_be64(s
->bitmap_directory_offset
)
2468 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_BITMAPS
,
2469 &bitmaps_header
, sizeof(bitmaps_header
),
2478 /* Keep unknown header extensions */
2479 QLIST_FOREACH(uext
, &s
->unknown_header_ext
, next
) {
2480 ret
= header_ext_add(buf
, uext
->magic
, uext
->data
, uext
->len
, buflen
);
2489 /* End of header extensions */
2490 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_END
, NULL
, 0, buflen
);
2498 /* Backing file name */
2499 if (s
->image_backing_file
) {
2500 size_t backing_file_len
= strlen(s
->image_backing_file
);
2502 if (buflen
< backing_file_len
) {
2507 /* Using strncpy is ok here, since buf is not NUL-terminated. */
2508 strncpy(buf
, s
->image_backing_file
, buflen
);
2510 header
->backing_file_offset
= cpu_to_be64(buf
- ((char*) header
));
2511 header
->backing_file_size
= cpu_to_be32(backing_file_len
);
2514 /* Write the new header */
2515 ret
= bdrv_pwrite(bs
->file
, 0, header
, s
->cluster_size
);
2526 static int qcow2_change_backing_file(BlockDriverState
*bs
,
2527 const char *backing_file
, const char *backing_fmt
)
2529 BDRVQcow2State
*s
= bs
->opaque
;
2531 if (backing_file
&& strlen(backing_file
) > 1023) {
2535 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
2536 backing_file
?: "");
2537 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
2538 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
2540 g_free(s
->image_backing_file
);
2541 g_free(s
->image_backing_format
);
2543 s
->image_backing_file
= backing_file
? g_strdup(bs
->backing_file
) : NULL
;
2544 s
->image_backing_format
= backing_fmt
? g_strdup(bs
->backing_format
) : NULL
;
2546 return qcow2_update_header(bs
);
2549 static int qcow2_crypt_method_from_format(const char *encryptfmt
)
2551 if (g_str_equal(encryptfmt
, "luks")) {
2552 return QCOW_CRYPT_LUKS
;
2553 } else if (g_str_equal(encryptfmt
, "aes")) {
2554 return QCOW_CRYPT_AES
;
2560 static int qcow2_set_up_encryption(BlockDriverState
*bs
,
2561 QCryptoBlockCreateOptions
*cryptoopts
,
2564 BDRVQcow2State
*s
= bs
->opaque
;
2565 QCryptoBlock
*crypto
= NULL
;
2568 switch (cryptoopts
->format
) {
2569 case Q_CRYPTO_BLOCK_FORMAT_LUKS
:
2570 fmt
= QCOW_CRYPT_LUKS
;
2572 case Q_CRYPTO_BLOCK_FORMAT_QCOW
:
2573 fmt
= QCOW_CRYPT_AES
;
2576 error_setg(errp
, "Crypto format not supported in qcow2");
2580 s
->crypt_method_header
= fmt
;
2582 crypto
= qcrypto_block_create(cryptoopts
, "encrypt.",
2583 qcow2_crypto_hdr_init_func
,
2584 qcow2_crypto_hdr_write_func
,
2590 ret
= qcow2_update_header(bs
);
2592 error_setg_errno(errp
, -ret
, "Could not write encryption header");
2598 qcrypto_block_free(crypto
);
2603 * Preallocates metadata structures for data clusters between @offset (in the
2604 * guest disk) and @new_length (which is thus generally the new guest disk
2607 * Returns: 0 on success, -errno on failure.
2609 static int coroutine_fn
preallocate_co(BlockDriverState
*bs
, uint64_t offset
,
2610 uint64_t new_length
)
2613 uint64_t host_offset
= 0;
2614 unsigned int cur_bytes
;
2618 assert(offset
<= new_length
);
2619 bytes
= new_length
- offset
;
2622 cur_bytes
= MIN(bytes
, INT_MAX
);
2623 ret
= qcow2_alloc_cluster_offset(bs
, offset
, &cur_bytes
,
2624 &host_offset
, &meta
);
2630 QCowL2Meta
*next
= meta
->next
;
2632 ret
= qcow2_alloc_cluster_link_l2(bs
, meta
);
2634 qcow2_free_any_clusters(bs
, meta
->alloc_offset
,
2635 meta
->nb_clusters
, QCOW2_DISCARD_NEVER
);
2639 /* There are no dependent requests, but we need to remove our
2640 * request from the list of in-flight requests */
2641 QLIST_REMOVE(meta
, next_in_flight
);
2647 /* TODO Preallocate data if requested */
2650 offset
+= cur_bytes
;
2654 * It is expected that the image file is large enough to actually contain
2655 * all of the allocated clusters (otherwise we get failing reads after
2656 * EOF). Extend the image to the last allocated sector.
2658 if (host_offset
!= 0) {
2660 ret
= bdrv_pwrite(bs
->file
, (host_offset
+ cur_bytes
) - 1,
2670 /* qcow2_refcount_metadata_size:
2671 * @clusters: number of clusters to refcount (including data and L1/L2 tables)
2672 * @cluster_size: size of a cluster, in bytes
2673 * @refcount_order: refcount bits power-of-2 exponent
2674 * @generous_increase: allow for the refcount table to be 1.5x as large as it
2677 * Returns: Number of bytes required for refcount blocks and table metadata.
2679 int64_t qcow2_refcount_metadata_size(int64_t clusters
, size_t cluster_size
,
2680 int refcount_order
, bool generous_increase
,
2681 uint64_t *refblock_count
)
2684 * Every host cluster is reference-counted, including metadata (even
2685 * refcount metadata is recursively included).
2687 * An accurate formula for the size of refcount metadata size is difficult
2688 * to derive. An easier method of calculation is finding the fixed point
2689 * where no further refcount blocks or table clusters are required to
2690 * reference count every cluster.
2692 int64_t blocks_per_table_cluster
= cluster_size
/ sizeof(uint64_t);
2693 int64_t refcounts_per_block
= cluster_size
* 8 / (1 << refcount_order
);
2694 int64_t table
= 0; /* number of refcount table clusters */
2695 int64_t blocks
= 0; /* number of refcount block clusters */
2701 blocks
= DIV_ROUND_UP(clusters
+ table
+ blocks
, refcounts_per_block
);
2702 table
= DIV_ROUND_UP(blocks
, blocks_per_table_cluster
);
2703 n
= clusters
+ blocks
+ table
;
2705 if (n
== last
&& generous_increase
) {
2706 clusters
+= DIV_ROUND_UP(table
, 2);
2707 n
= 0; /* force another loop */
2708 generous_increase
= false;
2710 } while (n
!= last
);
2712 if (refblock_count
) {
2713 *refblock_count
= blocks
;
2716 return (blocks
+ table
) * cluster_size
;
2720 * qcow2_calc_prealloc_size:
2721 * @total_size: virtual disk size in bytes
2722 * @cluster_size: cluster size in bytes
2723 * @refcount_order: refcount bits power-of-2 exponent
2725 * Returns: Total number of bytes required for the fully allocated image
2726 * (including metadata).
2728 static int64_t qcow2_calc_prealloc_size(int64_t total_size
,
2729 size_t cluster_size
,
2732 int64_t meta_size
= 0;
2733 uint64_t nl1e
, nl2e
;
2734 int64_t aligned_total_size
= ROUND_UP(total_size
, cluster_size
);
2736 /* header: 1 cluster */
2737 meta_size
+= cluster_size
;
2739 /* total size of L2 tables */
2740 nl2e
= aligned_total_size
/ cluster_size
;
2741 nl2e
= ROUND_UP(nl2e
, cluster_size
/ sizeof(uint64_t));
2742 meta_size
+= nl2e
* sizeof(uint64_t);
2744 /* total size of L1 tables */
2745 nl1e
= nl2e
* sizeof(uint64_t) / cluster_size
;
2746 nl1e
= ROUND_UP(nl1e
, cluster_size
/ sizeof(uint64_t));
2747 meta_size
+= nl1e
* sizeof(uint64_t);
2749 /* total size of refcount table and blocks */
2750 meta_size
+= qcow2_refcount_metadata_size(
2751 (meta_size
+ aligned_total_size
) / cluster_size
,
2752 cluster_size
, refcount_order
, false, NULL
);
2754 return meta_size
+ aligned_total_size
;
2757 static bool validate_cluster_size(size_t cluster_size
, Error
**errp
)
2759 int cluster_bits
= ctz32(cluster_size
);
2760 if (cluster_bits
< MIN_CLUSTER_BITS
|| cluster_bits
> MAX_CLUSTER_BITS
||
2761 (1 << cluster_bits
) != cluster_size
)
2763 error_setg(errp
, "Cluster size must be a power of two between %d and "
2764 "%dk", 1 << MIN_CLUSTER_BITS
, 1 << (MAX_CLUSTER_BITS
- 10));
2770 static size_t qcow2_opt_get_cluster_size_del(QemuOpts
*opts
, Error
**errp
)
2772 size_t cluster_size
;
2774 cluster_size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_CLUSTER_SIZE
,
2775 DEFAULT_CLUSTER_SIZE
);
2776 if (!validate_cluster_size(cluster_size
, errp
)) {
2779 return cluster_size
;
2782 static int qcow2_opt_get_version_del(QemuOpts
*opts
, Error
**errp
)
2787 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_COMPAT_LEVEL
);
2789 ret
= 3; /* default */
2790 } else if (!strcmp(buf
, "0.10")) {
2792 } else if (!strcmp(buf
, "1.1")) {
2795 error_setg(errp
, "Invalid compatibility level: '%s'", buf
);
2802 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts
*opts
, int version
,
2805 uint64_t refcount_bits
;
2807 refcount_bits
= qemu_opt_get_number_del(opts
, BLOCK_OPT_REFCOUNT_BITS
, 16);
2808 if (refcount_bits
> 64 || !is_power_of_2(refcount_bits
)) {
2809 error_setg(errp
, "Refcount width must be a power of two and may not "
2814 if (version
< 3 && refcount_bits
!= 16) {
2815 error_setg(errp
, "Different refcount widths than 16 bits require "
2816 "compatibility level 1.1 or above (use compat=1.1 or "
2821 return refcount_bits
;
2824 static int coroutine_fn
2825 qcow2_co_create(BlockdevCreateOptions
*create_options
, Error
**errp
)
2827 BlockdevCreateOptionsQcow2
*qcow2_opts
;
2831 * Open the image file and write a minimal qcow2 header.
2833 * We keep things simple and start with a zero-sized image. We also
2834 * do without refcount blocks or a L1 table for now. We'll fix the
2835 * inconsistency later.
2837 * We do need a refcount table because growing the refcount table means
2838 * allocating two new refcount blocks - the seconds of which would be at
2839 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
2840 * size for any qcow2 image.
2842 BlockBackend
*blk
= NULL
;
2843 BlockDriverState
*bs
= NULL
;
2845 size_t cluster_size
;
2848 uint64_t* refcount_table
;
2849 Error
*local_err
= NULL
;
2852 assert(create_options
->driver
== BLOCKDEV_DRIVER_QCOW2
);
2853 qcow2_opts
= &create_options
->u
.qcow2
;
2855 bs
= bdrv_open_blockdev_ref(qcow2_opts
->file
, errp
);
2860 /* Validate options and set default values */
2861 if (!QEMU_IS_ALIGNED(qcow2_opts
->size
, BDRV_SECTOR_SIZE
)) {
2862 error_setg(errp
, "Image size must be a multiple of 512 bytes");
2867 if (qcow2_opts
->has_version
) {
2868 switch (qcow2_opts
->version
) {
2869 case BLOCKDEV_QCOW2_VERSION_V2
:
2872 case BLOCKDEV_QCOW2_VERSION_V3
:
2876 g_assert_not_reached();
2882 if (qcow2_opts
->has_cluster_size
) {
2883 cluster_size
= qcow2_opts
->cluster_size
;
2885 cluster_size
= DEFAULT_CLUSTER_SIZE
;
2888 if (!validate_cluster_size(cluster_size
, errp
)) {
2893 if (!qcow2_opts
->has_preallocation
) {
2894 qcow2_opts
->preallocation
= PREALLOC_MODE_OFF
;
2896 if (qcow2_opts
->has_backing_file
&&
2897 qcow2_opts
->preallocation
!= PREALLOC_MODE_OFF
)
2899 error_setg(errp
, "Backing file and preallocation cannot be used at "
2904 if (qcow2_opts
->has_backing_fmt
&& !qcow2_opts
->has_backing_file
) {
2905 error_setg(errp
, "Backing format cannot be used without backing file");
2910 if (!qcow2_opts
->has_lazy_refcounts
) {
2911 qcow2_opts
->lazy_refcounts
= false;
2913 if (version
< 3 && qcow2_opts
->lazy_refcounts
) {
2914 error_setg(errp
, "Lazy refcounts only supported with compatibility "
2915 "level 1.1 and above (use version=v3 or greater)");
2920 if (!qcow2_opts
->has_refcount_bits
) {
2921 qcow2_opts
->refcount_bits
= 16;
2923 if (qcow2_opts
->refcount_bits
> 64 ||
2924 !is_power_of_2(qcow2_opts
->refcount_bits
))
2926 error_setg(errp
, "Refcount width must be a power of two and may not "
2931 if (version
< 3 && qcow2_opts
->refcount_bits
!= 16) {
2932 error_setg(errp
, "Different refcount widths than 16 bits require "
2933 "compatibility level 1.1 or above (use version=v3 or "
2938 refcount_order
= ctz32(qcow2_opts
->refcount_bits
);
2941 /* Create BlockBackend to write to the image */
2942 blk
= blk_new(BLK_PERM_WRITE
| BLK_PERM_RESIZE
, BLK_PERM_ALL
);
2943 ret
= blk_insert_bs(blk
, bs
, errp
);
2947 blk_set_allow_write_beyond_eof(blk
, true);
2949 /* Clear the protocol layer and preallocate it if necessary */
2950 ret
= blk_truncate(blk
, 0, PREALLOC_MODE_OFF
, errp
);
2955 if (qcow2_opts
->preallocation
== PREALLOC_MODE_FULL
||
2956 qcow2_opts
->preallocation
== PREALLOC_MODE_FALLOC
)
2958 int64_t prealloc_size
=
2959 qcow2_calc_prealloc_size(qcow2_opts
->size
, cluster_size
,
2962 ret
= blk_truncate(blk
, prealloc_size
, qcow2_opts
->preallocation
, errp
);
2968 /* Write the header */
2969 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS
) < sizeof(*header
));
2970 header
= g_malloc0(cluster_size
);
2971 *header
= (QCowHeader
) {
2972 .magic
= cpu_to_be32(QCOW_MAGIC
),
2973 .version
= cpu_to_be32(version
),
2974 .cluster_bits
= cpu_to_be32(ctz32(cluster_size
)),
2975 .size
= cpu_to_be64(0),
2976 .l1_table_offset
= cpu_to_be64(0),
2977 .l1_size
= cpu_to_be32(0),
2978 .refcount_table_offset
= cpu_to_be64(cluster_size
),
2979 .refcount_table_clusters
= cpu_to_be32(1),
2980 .refcount_order
= cpu_to_be32(refcount_order
),
2981 .header_length
= cpu_to_be32(sizeof(*header
)),
2984 /* We'll update this to correct value later */
2985 header
->crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
2987 if (qcow2_opts
->lazy_refcounts
) {
2988 header
->compatible_features
|=
2989 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS
);
2992 ret
= blk_pwrite(blk
, 0, header
, cluster_size
, 0);
2995 error_setg_errno(errp
, -ret
, "Could not write qcow2 header");
2999 /* Write a refcount table with one refcount block */
3000 refcount_table
= g_malloc0(2 * cluster_size
);
3001 refcount_table
[0] = cpu_to_be64(2 * cluster_size
);
3002 ret
= blk_pwrite(blk
, cluster_size
, refcount_table
, 2 * cluster_size
, 0);
3003 g_free(refcount_table
);
3006 error_setg_errno(errp
, -ret
, "Could not write refcount table");
3014 * And now open the image and make it consistent first (i.e. increase the
3015 * refcount of the cluster that is occupied by the header and the refcount
3018 options
= qdict_new();
3019 qdict_put_str(options
, "driver", "qcow2");
3020 qdict_put_str(options
, "file", bs
->node_name
);
3021 blk
= blk_new_open(NULL
, NULL
, options
,
3022 BDRV_O_RDWR
| BDRV_O_RESIZE
| BDRV_O_NO_FLUSH
,
3025 error_propagate(errp
, local_err
);
3030 ret
= qcow2_alloc_clusters(blk_bs(blk
), 3 * cluster_size
);
3032 error_setg_errno(errp
, -ret
, "Could not allocate clusters for qcow2 "
3033 "header and refcount table");
3036 } else if (ret
!= 0) {
3037 error_report("Huh, first cluster in empty image is already in use?");
3041 /* Create a full header (including things like feature table) */
3042 ret
= qcow2_update_header(blk_bs(blk
));
3044 error_setg_errno(errp
, -ret
, "Could not update qcow2 header");
3048 /* Okay, now that we have a valid image, let's give it the right size */
3049 ret
= blk_truncate(blk
, qcow2_opts
->size
, PREALLOC_MODE_OFF
, errp
);
3051 error_prepend(errp
, "Could not resize image: ");
3055 /* Want a backing file? There you go.*/
3056 if (qcow2_opts
->has_backing_file
) {
3057 const char *backing_format
= NULL
;
3059 if (qcow2_opts
->has_backing_fmt
) {
3060 backing_format
= BlockdevDriver_str(qcow2_opts
->backing_fmt
);
3063 ret
= bdrv_change_backing_file(blk_bs(blk
), qcow2_opts
->backing_file
,
3066 error_setg_errno(errp
, -ret
, "Could not assign backing file '%s' "
3067 "with format '%s'", qcow2_opts
->backing_file
,
3073 /* Want encryption? There you go. */
3074 if (qcow2_opts
->has_encrypt
) {
3075 ret
= qcow2_set_up_encryption(blk_bs(blk
), qcow2_opts
->encrypt
, errp
);
3081 /* And if we're supposed to preallocate metadata, do that now */
3082 if (qcow2_opts
->preallocation
!= PREALLOC_MODE_OFF
) {
3083 BDRVQcow2State
*s
= blk_bs(blk
)->opaque
;
3084 qemu_co_mutex_lock(&s
->lock
);
3085 ret
= preallocate_co(blk_bs(blk
), 0, qcow2_opts
->size
);
3086 qemu_co_mutex_unlock(&s
->lock
);
3089 error_setg_errno(errp
, -ret
, "Could not preallocate metadata");
3097 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning.
3098 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to
3099 * have to setup decryption context. We're not doing any I/O on the top
3100 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does
3103 options
= qdict_new();
3104 qdict_put_str(options
, "driver", "qcow2");
3105 qdict_put_str(options
, "file", bs
->node_name
);
3106 blk
= blk_new_open(NULL
, NULL
, options
,
3107 BDRV_O_RDWR
| BDRV_O_NO_BACKING
| BDRV_O_NO_IO
,
3110 error_propagate(errp
, local_err
);
3122 static int coroutine_fn
qcow2_co_create_opts(const char *filename
, QemuOpts
*opts
,
3125 BlockdevCreateOptions
*create_options
= NULL
;
3128 BlockDriverState
*bs
= NULL
;
3129 Error
*local_err
= NULL
;
3133 /* Only the keyval visitor supports the dotted syntax needed for
3134 * encryption, so go through a QDict before getting a QAPI type. Ignore
3135 * options meant for the protocol layer so that the visitor doesn't
3137 qdict
= qemu_opts_to_qdict_filtered(opts
, NULL
, bdrv_qcow2
.create_opts
,
3140 /* Handle encryption options */
3141 val
= qdict_get_try_str(qdict
, BLOCK_OPT_ENCRYPT
);
3142 if (val
&& !strcmp(val
, "on")) {
3143 qdict_put_str(qdict
, BLOCK_OPT_ENCRYPT
, "qcow");
3144 } else if (val
&& !strcmp(val
, "off")) {
3145 qdict_del(qdict
, BLOCK_OPT_ENCRYPT
);
3148 val
= qdict_get_try_str(qdict
, BLOCK_OPT_ENCRYPT_FORMAT
);
3149 if (val
&& !strcmp(val
, "aes")) {
3150 qdict_put_str(qdict
, BLOCK_OPT_ENCRYPT_FORMAT
, "qcow");
3153 /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into
3154 * version=v2/v3 below. */
3155 val
= qdict_get_try_str(qdict
, BLOCK_OPT_COMPAT_LEVEL
);
3156 if (val
&& !strcmp(val
, "0.10")) {
3157 qdict_put_str(qdict
, BLOCK_OPT_COMPAT_LEVEL
, "v2");
3158 } else if (val
&& !strcmp(val
, "1.1")) {
3159 qdict_put_str(qdict
, BLOCK_OPT_COMPAT_LEVEL
, "v3");
3162 /* Change legacy command line options into QMP ones */
3163 static const QDictRenames opt_renames
[] = {
3164 { BLOCK_OPT_BACKING_FILE
, "backing-file" },
3165 { BLOCK_OPT_BACKING_FMT
, "backing-fmt" },
3166 { BLOCK_OPT_CLUSTER_SIZE
, "cluster-size" },
3167 { BLOCK_OPT_LAZY_REFCOUNTS
, "lazy-refcounts" },
3168 { BLOCK_OPT_REFCOUNT_BITS
, "refcount-bits" },
3169 { BLOCK_OPT_ENCRYPT
, BLOCK_OPT_ENCRYPT_FORMAT
},
3170 { BLOCK_OPT_COMPAT_LEVEL
, "version" },
3174 if (!qdict_rename_keys(qdict
, opt_renames
, errp
)) {
3179 /* Create and open the file (protocol layer) */
3180 ret
= bdrv_create_file(filename
, opts
, errp
);
3185 bs
= bdrv_open(filename
, NULL
, NULL
,
3186 BDRV_O_RDWR
| BDRV_O_RESIZE
| BDRV_O_PROTOCOL
, errp
);
3192 /* Set 'driver' and 'node' options */
3193 qdict_put_str(qdict
, "driver", "qcow2");
3194 qdict_put_str(qdict
, "file", bs
->node_name
);
3196 /* Now get the QAPI type BlockdevCreateOptions */
3197 v
= qobject_input_visitor_new_flat_confused(qdict
, errp
);
3203 visit_type_BlockdevCreateOptions(v
, NULL
, &create_options
, &local_err
);
3207 error_propagate(errp
, local_err
);
3212 /* Silently round up size */
3213 create_options
->u
.qcow2
.size
= ROUND_UP(create_options
->u
.qcow2
.size
,
3216 /* Create the qcow2 image (format layer) */
3217 ret
= qcow2_co_create(create_options
, errp
);
3224 qobject_unref(qdict
);
3226 qapi_free_BlockdevCreateOptions(create_options
);
3231 static bool is_zero(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
)
3236 /* Clamp to image length, before checking status of underlying sectors */
3237 if (offset
+ bytes
> bs
->total_sectors
* BDRV_SECTOR_SIZE
) {
3238 bytes
= bs
->total_sectors
* BDRV_SECTOR_SIZE
- offset
;
3244 res
= bdrv_block_status_above(bs
, NULL
, offset
, bytes
, &nr
, NULL
, NULL
);
3245 return res
>= 0 && (res
& BDRV_BLOCK_ZERO
) && nr
== bytes
;
3248 static coroutine_fn
int qcow2_co_pwrite_zeroes(BlockDriverState
*bs
,
3249 int64_t offset
, int bytes
, BdrvRequestFlags flags
)
3252 BDRVQcow2State
*s
= bs
->opaque
;
3254 uint32_t head
= offset
% s
->cluster_size
;
3255 uint32_t tail
= (offset
+ bytes
) % s
->cluster_size
;
3257 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset
, bytes
);
3258 if (offset
+ bytes
== bs
->total_sectors
* BDRV_SECTOR_SIZE
) {
3266 assert(head
+ bytes
<= s
->cluster_size
);
3268 /* check whether remainder of cluster already reads as zero */
3269 if (!(is_zero(bs
, offset
- head
, head
) &&
3270 is_zero(bs
, offset
+ bytes
,
3271 tail
? s
->cluster_size
- tail
: 0))) {
3275 qemu_co_mutex_lock(&s
->lock
);
3276 /* We can have new write after previous check */
3277 offset
= QEMU_ALIGN_DOWN(offset
, s
->cluster_size
);
3278 bytes
= s
->cluster_size
;
3279 nr
= s
->cluster_size
;
3280 ret
= qcow2_get_cluster_offset(bs
, offset
, &nr
, &off
);
3281 if (ret
!= QCOW2_CLUSTER_UNALLOCATED
&&
3282 ret
!= QCOW2_CLUSTER_ZERO_PLAIN
&&
3283 ret
!= QCOW2_CLUSTER_ZERO_ALLOC
) {
3284 qemu_co_mutex_unlock(&s
->lock
);
3288 qemu_co_mutex_lock(&s
->lock
);
3291 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset
, bytes
);
3293 /* Whatever is left can use real zero clusters */
3294 ret
= qcow2_cluster_zeroize(bs
, offset
, bytes
, flags
);
3295 qemu_co_mutex_unlock(&s
->lock
);
3300 static coroutine_fn
int qcow2_co_pdiscard(BlockDriverState
*bs
,
3301 int64_t offset
, int bytes
)
3304 BDRVQcow2State
*s
= bs
->opaque
;
3306 if (!QEMU_IS_ALIGNED(offset
| bytes
, s
->cluster_size
)) {
3307 assert(bytes
< s
->cluster_size
);
3308 /* Ignore partial clusters, except for the special case of the
3309 * complete partial cluster at the end of an unaligned file */
3310 if (!QEMU_IS_ALIGNED(offset
, s
->cluster_size
) ||
3311 offset
+ bytes
!= bs
->total_sectors
* BDRV_SECTOR_SIZE
) {
3316 qemu_co_mutex_lock(&s
->lock
);
3317 ret
= qcow2_cluster_discard(bs
, offset
, bytes
, QCOW2_DISCARD_REQUEST
,
3319 qemu_co_mutex_unlock(&s
->lock
);
3323 static int coroutine_fn
3324 qcow2_co_copy_range_from(BlockDriverState
*bs
,
3325 BdrvChild
*src
, uint64_t src_offset
,
3326 BdrvChild
*dst
, uint64_t dst_offset
,
3327 uint64_t bytes
, BdrvRequestFlags read_flags
,
3328 BdrvRequestFlags write_flags
)
3330 BDRVQcow2State
*s
= bs
->opaque
;
3332 unsigned int cur_bytes
; /* number of bytes in current iteration */
3333 BdrvChild
*child
= NULL
;
3334 BdrvRequestFlags cur_write_flags
;
3336 assert(!bs
->encrypted
);
3337 qemu_co_mutex_lock(&s
->lock
);
3339 while (bytes
!= 0) {
3340 uint64_t copy_offset
= 0;
3341 /* prepare next request */
3342 cur_bytes
= MIN(bytes
, INT_MAX
);
3343 cur_write_flags
= write_flags
;
3345 ret
= qcow2_get_cluster_offset(bs
, src_offset
, &cur_bytes
, ©_offset
);
3351 case QCOW2_CLUSTER_UNALLOCATED
:
3352 if (bs
->backing
&& bs
->backing
->bs
) {
3353 int64_t backing_length
= bdrv_getlength(bs
->backing
->bs
);
3354 if (src_offset
>= backing_length
) {
3355 cur_write_flags
|= BDRV_REQ_ZERO_WRITE
;
3357 child
= bs
->backing
;
3358 cur_bytes
= MIN(cur_bytes
, backing_length
- src_offset
);
3359 copy_offset
= src_offset
;
3362 cur_write_flags
|= BDRV_REQ_ZERO_WRITE
;
3366 case QCOW2_CLUSTER_ZERO_PLAIN
:
3367 case QCOW2_CLUSTER_ZERO_ALLOC
:
3368 cur_write_flags
|= BDRV_REQ_ZERO_WRITE
;
3371 case QCOW2_CLUSTER_COMPRESSED
:
3375 case QCOW2_CLUSTER_NORMAL
:
3377 copy_offset
+= offset_into_cluster(s
, src_offset
);
3378 if ((copy_offset
& 511) != 0) {
3387 qemu_co_mutex_unlock(&s
->lock
);
3388 ret
= bdrv_co_copy_range_from(child
,
3391 cur_bytes
, read_flags
, cur_write_flags
);
3392 qemu_co_mutex_lock(&s
->lock
);
3398 src_offset
+= cur_bytes
;
3399 dst_offset
+= cur_bytes
;
3404 qemu_co_mutex_unlock(&s
->lock
);
3408 static int coroutine_fn
3409 qcow2_co_copy_range_to(BlockDriverState
*bs
,
3410 BdrvChild
*src
, uint64_t src_offset
,
3411 BdrvChild
*dst
, uint64_t dst_offset
,
3412 uint64_t bytes
, BdrvRequestFlags read_flags
,
3413 BdrvRequestFlags write_flags
)
3415 BDRVQcow2State
*s
= bs
->opaque
;
3416 int offset_in_cluster
;
3418 unsigned int cur_bytes
; /* number of sectors in current iteration */
3419 uint64_t cluster_offset
;
3420 QCowL2Meta
*l2meta
= NULL
;
3422 assert(!bs
->encrypted
);
3424 qemu_co_mutex_lock(&s
->lock
);
3426 while (bytes
!= 0) {
3430 offset_in_cluster
= offset_into_cluster(s
, dst_offset
);
3431 cur_bytes
= MIN(bytes
, INT_MAX
);
3434 * If src->bs == dst->bs, we could simply copy by incrementing
3435 * the refcnt, without copying user data.
3436 * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */
3437 ret
= qcow2_alloc_cluster_offset(bs
, dst_offset
, &cur_bytes
,
3438 &cluster_offset
, &l2meta
);
3443 assert((cluster_offset
& 511) == 0);
3445 ret
= qcow2_pre_write_overlap_check(bs
, 0,
3446 cluster_offset
+ offset_in_cluster
, cur_bytes
);
3451 qemu_co_mutex_unlock(&s
->lock
);
3452 ret
= bdrv_co_copy_range_to(src
, src_offset
,
3454 cluster_offset
+ offset_in_cluster
,
3455 cur_bytes
, read_flags
, write_flags
);
3456 qemu_co_mutex_lock(&s
->lock
);
3461 ret
= qcow2_handle_l2meta(bs
, &l2meta
, true);
3467 src_offset
+= cur_bytes
;
3468 dst_offset
+= cur_bytes
;
3473 qcow2_handle_l2meta(bs
, &l2meta
, false);
3475 qemu_co_mutex_unlock(&s
->lock
);
3477 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret
);
3482 static int coroutine_fn
qcow2_co_truncate(BlockDriverState
*bs
, int64_t offset
,
3483 PreallocMode prealloc
, Error
**errp
)
3485 BDRVQcow2State
*s
= bs
->opaque
;
3486 uint64_t old_length
;
3487 int64_t new_l1_size
;
3491 if (prealloc
!= PREALLOC_MODE_OFF
&& prealloc
!= PREALLOC_MODE_METADATA
&&
3492 prealloc
!= PREALLOC_MODE_FALLOC
&& prealloc
!= PREALLOC_MODE_FULL
)
3494 error_setg(errp
, "Unsupported preallocation mode '%s'",
3495 PreallocMode_str(prealloc
));
3500 error_setg(errp
, "The new size must be a multiple of 512");
3504 qemu_co_mutex_lock(&s
->lock
);
3506 /* cannot proceed if image has snapshots */
3507 if (s
->nb_snapshots
) {
3508 error_setg(errp
, "Can't resize an image which has snapshots");
3513 /* cannot proceed if image has bitmaps */
3514 if (s
->nb_bitmaps
) {
3515 /* TODO: resize bitmaps in the image */
3516 error_setg(errp
, "Can't resize an image which has bitmaps");
3521 old_length
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
3522 new_l1_size
= size_to_l1(s
, offset
);
3524 if (offset
< old_length
) {
3525 int64_t last_cluster
, old_file_size
;
3526 if (prealloc
!= PREALLOC_MODE_OFF
) {
3528 "Preallocation can't be used for shrinking an image");
3533 ret
= qcow2_cluster_discard(bs
, ROUND_UP(offset
, s
->cluster_size
),
3534 old_length
- ROUND_UP(offset
,
3536 QCOW2_DISCARD_ALWAYS
, true);
3538 error_setg_errno(errp
, -ret
, "Failed to discard cropped clusters");
3542 ret
= qcow2_shrink_l1_table(bs
, new_l1_size
);
3544 error_setg_errno(errp
, -ret
,
3545 "Failed to reduce the number of L2 tables");
3549 ret
= qcow2_shrink_reftable(bs
);
3551 error_setg_errno(errp
, -ret
,
3552 "Failed to discard unused refblocks");
3556 old_file_size
= bdrv_getlength(bs
->file
->bs
);
3557 if (old_file_size
< 0) {
3558 error_setg_errno(errp
, -old_file_size
,
3559 "Failed to inquire current file length");
3560 ret
= old_file_size
;
3563 last_cluster
= qcow2_get_last_cluster(bs
, old_file_size
);
3564 if (last_cluster
< 0) {
3565 error_setg_errno(errp
, -last_cluster
,
3566 "Failed to find the last cluster");
3570 if ((last_cluster
+ 1) * s
->cluster_size
< old_file_size
) {
3571 Error
*local_err
= NULL
;
3573 bdrv_co_truncate(bs
->file
, (last_cluster
+ 1) * s
->cluster_size
,
3574 PREALLOC_MODE_OFF
, &local_err
);
3576 warn_reportf_err(local_err
,
3577 "Failed to truncate the tail of the image: ");
3581 ret
= qcow2_grow_l1_table(bs
, new_l1_size
, true);
3583 error_setg_errno(errp
, -ret
, "Failed to grow the L1 table");
3589 case PREALLOC_MODE_OFF
:
3592 case PREALLOC_MODE_METADATA
:
3593 ret
= preallocate_co(bs
, old_length
, offset
);
3595 error_setg_errno(errp
, -ret
, "Preallocation failed");
3600 case PREALLOC_MODE_FALLOC
:
3601 case PREALLOC_MODE_FULL
:
3603 int64_t allocation_start
, host_offset
, guest_offset
;
3604 int64_t clusters_allocated
;
3605 int64_t old_file_size
, new_file_size
;
3606 uint64_t nb_new_data_clusters
, nb_new_l2_tables
;
3608 old_file_size
= bdrv_getlength(bs
->file
->bs
);
3609 if (old_file_size
< 0) {
3610 error_setg_errno(errp
, -old_file_size
,
3611 "Failed to inquire current file length");
3612 ret
= old_file_size
;
3615 old_file_size
= ROUND_UP(old_file_size
, s
->cluster_size
);
3617 nb_new_data_clusters
= DIV_ROUND_UP(offset
- old_length
,
3620 /* This is an overestimation; we will not actually allocate space for
3621 * these in the file but just make sure the new refcount structures are
3622 * able to cover them so we will not have to allocate new refblocks
3623 * while entering the data blocks in the potentially new L2 tables.
3624 * (We do not actually care where the L2 tables are placed. Maybe they
3625 * are already allocated or they can be placed somewhere before
3626 * @old_file_size. It does not matter because they will be fully
3627 * allocated automatically, so they do not need to be covered by the
3628 * preallocation. All that matters is that we will not have to allocate
3629 * new refcount structures for them.) */
3630 nb_new_l2_tables
= DIV_ROUND_UP(nb_new_data_clusters
,
3631 s
->cluster_size
/ sizeof(uint64_t));
3632 /* The cluster range may not be aligned to L2 boundaries, so add one L2
3633 * table for a potential head/tail */
3636 allocation_start
= qcow2_refcount_area(bs
, old_file_size
,
3637 nb_new_data_clusters
+
3640 if (allocation_start
< 0) {
3641 error_setg_errno(errp
, -allocation_start
,
3642 "Failed to resize refcount structures");
3643 ret
= allocation_start
;
3647 clusters_allocated
= qcow2_alloc_clusters_at(bs
, allocation_start
,
3648 nb_new_data_clusters
);
3649 if (clusters_allocated
< 0) {
3650 error_setg_errno(errp
, -clusters_allocated
,
3651 "Failed to allocate data clusters");
3652 ret
= clusters_allocated
;
3656 assert(clusters_allocated
== nb_new_data_clusters
);
3658 /* Allocate the data area */
3659 new_file_size
= allocation_start
+
3660 nb_new_data_clusters
* s
->cluster_size
;
3661 ret
= bdrv_co_truncate(bs
->file
, new_file_size
, prealloc
, errp
);
3663 error_prepend(errp
, "Failed to resize underlying file: ");
3664 qcow2_free_clusters(bs
, allocation_start
,
3665 nb_new_data_clusters
* s
->cluster_size
,
3666 QCOW2_DISCARD_OTHER
);
3670 /* Create the necessary L2 entries */
3671 host_offset
= allocation_start
;
3672 guest_offset
= old_length
;
3673 while (nb_new_data_clusters
) {
3674 int64_t nb_clusters
= MIN(
3675 nb_new_data_clusters
,
3676 s
->l2_slice_size
- offset_to_l2_slice_index(s
, guest_offset
));
3677 QCowL2Meta allocation
= {
3678 .offset
= guest_offset
,
3679 .alloc_offset
= host_offset
,
3680 .nb_clusters
= nb_clusters
,
3682 qemu_co_queue_init(&allocation
.dependent_requests
);
3684 ret
= qcow2_alloc_cluster_link_l2(bs
, &allocation
);
3686 error_setg_errno(errp
, -ret
, "Failed to update L2 tables");
3687 qcow2_free_clusters(bs
, host_offset
,
3688 nb_new_data_clusters
* s
->cluster_size
,
3689 QCOW2_DISCARD_OTHER
);
3693 guest_offset
+= nb_clusters
* s
->cluster_size
;
3694 host_offset
+= nb_clusters
* s
->cluster_size
;
3695 nb_new_data_clusters
-= nb_clusters
;
3701 g_assert_not_reached();
3704 if (prealloc
!= PREALLOC_MODE_OFF
) {
3705 /* Flush metadata before actually changing the image size */
3706 ret
= qcow2_write_caches(bs
);
3708 error_setg_errno(errp
, -ret
,
3709 "Failed to flush the preallocated area to disk");
3714 bs
->total_sectors
= offset
/ BDRV_SECTOR_SIZE
;
3716 /* write updated header.size */
3717 offset
= cpu_to_be64(offset
);
3718 ret
= bdrv_pwrite_sync(bs
->file
, offsetof(QCowHeader
, size
),
3719 &offset
, sizeof(uint64_t));
3721 error_setg_errno(errp
, -ret
, "Failed to update the image size");
3725 s
->l1_vm_state_index
= new_l1_size
;
3727 /* Update cache sizes */
3728 options
= qdict_clone_shallow(bs
->options
);
3729 ret
= qcow2_update_options(bs
, options
, s
->flags
, errp
);
3730 qobject_unref(options
);
3736 qemu_co_mutex_unlock(&s
->lock
);
3743 * @dest - destination buffer, @dest_size bytes
3744 * @src - source buffer, @src_size bytes
3746 * Returns: compressed size on success
3747 * -1 destination buffer is not enough to store compressed data
3748 * -2 on any other error
3750 static ssize_t
qcow2_compress(void *dest
, size_t dest_size
,
3751 const void *src
, size_t src_size
)
3756 /* best compression, small window, no zlib header */
3757 memset(&strm
, 0, sizeof(strm
));
3758 ret
= deflateInit2(&strm
, Z_DEFAULT_COMPRESSION
, Z_DEFLATED
,
3759 -12, 9, Z_DEFAULT_STRATEGY
);
3764 /* strm.next_in is not const in old zlib versions, such as those used on
3765 * OpenBSD/NetBSD, so cast the const away */
3766 strm
.avail_in
= src_size
;
3767 strm
.next_in
= (void *) src
;
3768 strm
.avail_out
= dest_size
;
3769 strm
.next_out
= dest
;
3771 ret
= deflate(&strm
, Z_FINISH
);
3772 if (ret
== Z_STREAM_END
) {
3773 ret
= dest_size
- strm
.avail_out
;
3775 ret
= (ret
== Z_OK
? -1 : -2);
3784 * qcow2_decompress()
3786 * Decompress some data (not more than @src_size bytes) to produce exactly
3789 * @dest - destination buffer, @dest_size bytes
3790 * @src - source buffer, @src_size bytes
3792 * Returns: 0 on success
3795 static ssize_t
qcow2_decompress(void *dest
, size_t dest_size
,
3796 const void *src
, size_t src_size
)
3801 memset(&strm
, 0, sizeof(strm
));
3802 strm
.avail_in
= src_size
;
3803 strm
.next_in
= (void *) src
;
3804 strm
.avail_out
= dest_size
;
3805 strm
.next_out
= dest
;
3807 ret
= inflateInit2(&strm
, -12);
3812 ret
= inflate(&strm
, Z_FINISH
);
3813 if ((ret
!= Z_STREAM_END
&& ret
!= Z_BUF_ERROR
) || strm
.avail_out
!= 0) {
3814 /* We approve Z_BUF_ERROR because we need @dest buffer to be filled, but
3815 * @src buffer may be processed partly (because in qcow2 we know size of
3816 * compressed data with precision of one sector) */
3825 #define MAX_COMPRESS_THREADS 4
3827 typedef ssize_t (*Qcow2CompressFunc
)(void *dest
, size_t dest_size
,
3828 const void *src
, size_t src_size
);
3829 typedef struct Qcow2CompressData
{
3836 Qcow2CompressFunc func
;
3837 } Qcow2CompressData
;
3839 static int qcow2_compress_pool_func(void *opaque
)
3841 Qcow2CompressData
*data
= opaque
;
3843 data
->ret
= data
->func(data
->dest
, data
->dest_size
,
3844 data
->src
, data
->src_size
);
3849 static void qcow2_compress_complete(void *opaque
, int ret
)
3851 qemu_coroutine_enter(opaque
);
3854 static ssize_t coroutine_fn
3855 qcow2_co_do_compress(BlockDriverState
*bs
, void *dest
, size_t dest_size
,
3856 const void *src
, size_t src_size
, Qcow2CompressFunc func
)
3858 BDRVQcow2State
*s
= bs
->opaque
;
3860 ThreadPool
*pool
= aio_get_thread_pool(bdrv_get_aio_context(bs
));
3861 Qcow2CompressData arg
= {
3863 .dest_size
= dest_size
,
3865 .src_size
= src_size
,
3869 while (s
->nb_compress_threads
>= MAX_COMPRESS_THREADS
) {
3870 qemu_co_queue_wait(&s
->compress_wait_queue
, NULL
);
3873 s
->nb_compress_threads
++;
3874 acb
= thread_pool_submit_aio(pool
, qcow2_compress_pool_func
, &arg
,
3875 qcow2_compress_complete
,
3876 qemu_coroutine_self());
3879 s
->nb_compress_threads
--;
3882 qemu_coroutine_yield();
3883 s
->nb_compress_threads
--;
3884 qemu_co_queue_next(&s
->compress_wait_queue
);
3889 static ssize_t coroutine_fn
3890 qcow2_co_compress(BlockDriverState
*bs
, void *dest
, size_t dest_size
,
3891 const void *src
, size_t src_size
)
3893 return qcow2_co_do_compress(bs
, dest
, dest_size
, src
, src_size
,
3897 static ssize_t coroutine_fn
3898 qcow2_co_decompress(BlockDriverState
*bs
, void *dest
, size_t dest_size
,
3899 const void *src
, size_t src_size
)
3901 return qcow2_co_do_compress(bs
, dest
, dest_size
, src
, src_size
,
3905 /* XXX: put compressed sectors first, then all the cluster aligned
3906 tables to avoid losing bytes in alignment */
3907 static coroutine_fn
int
3908 qcow2_co_pwritev_compressed(BlockDriverState
*bs
, uint64_t offset
,
3909 uint64_t bytes
, QEMUIOVector
*qiov
)
3911 BDRVQcow2State
*s
= bs
->opaque
;
3912 QEMUIOVector hd_qiov
;
3915 uint8_t *buf
, *out_buf
;
3916 int64_t cluster_offset
;
3919 /* align end of file to a sector boundary to ease reading with
3920 sector based I/Os */
3921 cluster_offset
= bdrv_getlength(bs
->file
->bs
);
3922 if (cluster_offset
< 0) {
3923 return cluster_offset
;
3925 return bdrv_co_truncate(bs
->file
, cluster_offset
, PREALLOC_MODE_OFF
,
3929 if (offset_into_cluster(s
, offset
)) {
3933 buf
= qemu_blockalign(bs
, s
->cluster_size
);
3934 if (bytes
!= s
->cluster_size
) {
3935 if (bytes
> s
->cluster_size
||
3936 offset
+ bytes
!= bs
->total_sectors
<< BDRV_SECTOR_BITS
)
3941 /* Zero-pad last write if image size is not cluster aligned */
3942 memset(buf
+ bytes
, 0, s
->cluster_size
- bytes
);
3944 qemu_iovec_to_buf(qiov
, 0, buf
, bytes
);
3946 out_buf
= g_malloc(s
->cluster_size
);
3948 out_len
= qcow2_co_compress(bs
, out_buf
, s
->cluster_size
- 1,
3949 buf
, s
->cluster_size
);
3950 if (out_len
== -2) {
3953 } else if (out_len
== -1) {
3954 /* could not compress: write normal cluster */
3955 ret
= qcow2_co_pwritev(bs
, offset
, bytes
, qiov
, 0);
3962 qemu_co_mutex_lock(&s
->lock
);
3964 qcow2_alloc_compressed_cluster_offset(bs
, offset
, out_len
);
3965 if (!cluster_offset
) {
3966 qemu_co_mutex_unlock(&s
->lock
);
3970 cluster_offset
&= s
->cluster_offset_mask
;
3972 ret
= qcow2_pre_write_overlap_check(bs
, 0, cluster_offset
, out_len
);
3973 qemu_co_mutex_unlock(&s
->lock
);
3978 qemu_iovec_init_buf(&hd_qiov
, out_buf
, out_len
);
3980 BLKDBG_EVENT(bs
->file
, BLKDBG_WRITE_COMPRESSED
);
3981 ret
= bdrv_co_pwritev(bs
->file
, cluster_offset
, out_len
, &hd_qiov
, 0);
3993 static int coroutine_fn
3994 qcow2_co_preadv_compressed(BlockDriverState
*bs
,
3995 uint64_t file_cluster_offset
,
4000 BDRVQcow2State
*s
= bs
->opaque
;
4001 int ret
= 0, csize
, nb_csectors
;
4003 uint8_t *buf
, *out_buf
;
4004 QEMUIOVector local_qiov
;
4005 int offset_in_cluster
= offset_into_cluster(s
, offset
);
4007 coffset
= file_cluster_offset
& s
->cluster_offset_mask
;
4008 nb_csectors
= ((file_cluster_offset
>> s
->csize_shift
) & s
->csize_mask
) + 1;
4009 csize
= nb_csectors
* 512 - (coffset
& 511);
4011 buf
= g_try_malloc(csize
);
4015 qemu_iovec_init_buf(&local_qiov
, buf
, csize
);
4017 out_buf
= qemu_blockalign(bs
, s
->cluster_size
);
4019 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_COMPRESSED
);
4020 ret
= bdrv_co_preadv(bs
->file
, coffset
, csize
, &local_qiov
, 0);
4025 if (qcow2_co_decompress(bs
, out_buf
, s
->cluster_size
, buf
, csize
) < 0) {
4030 qemu_iovec_from_buf(qiov
, 0, out_buf
+ offset_in_cluster
, bytes
);
4033 qemu_vfree(out_buf
);
4039 static int make_completely_empty(BlockDriverState
*bs
)
4041 BDRVQcow2State
*s
= bs
->opaque
;
4042 Error
*local_err
= NULL
;
4043 int ret
, l1_clusters
;
4045 uint64_t *new_reftable
= NULL
;
4046 uint64_t rt_entry
, l1_size2
;
4049 uint64_t reftable_offset
;
4050 uint32_t reftable_clusters
;
4051 } QEMU_PACKED l1_ofs_rt_ofs_cls
;
4053 ret
= qcow2_cache_empty(bs
, s
->l2_table_cache
);
4058 ret
= qcow2_cache_empty(bs
, s
->refcount_block_cache
);
4063 /* Refcounts will be broken utterly */
4064 ret
= qcow2_mark_dirty(bs
);
4069 BLKDBG_EVENT(bs
->file
, BLKDBG_L1_UPDATE
);
4071 l1_clusters
= DIV_ROUND_UP(s
->l1_size
, s
->cluster_size
/ sizeof(uint64_t));
4072 l1_size2
= (uint64_t)s
->l1_size
* sizeof(uint64_t);
4074 /* After this call, neither the in-memory nor the on-disk refcount
4075 * information accurately describe the actual references */
4077 ret
= bdrv_pwrite_zeroes(bs
->file
, s
->l1_table_offset
,
4078 l1_clusters
* s
->cluster_size
, 0);
4080 goto fail_broken_refcounts
;
4082 memset(s
->l1_table
, 0, l1_size2
);
4084 BLKDBG_EVENT(bs
->file
, BLKDBG_EMPTY_IMAGE_PREPARE
);
4086 /* Overwrite enough clusters at the beginning of the sectors to place
4087 * the refcount table, a refcount block and the L1 table in; this may
4088 * overwrite parts of the existing refcount and L1 table, which is not
4089 * an issue because the dirty flag is set, complete data loss is in fact
4090 * desired and partial data loss is consequently fine as well */
4091 ret
= bdrv_pwrite_zeroes(bs
->file
, s
->cluster_size
,
4092 (2 + l1_clusters
) * s
->cluster_size
, 0);
4093 /* This call (even if it failed overall) may have overwritten on-disk
4094 * refcount structures; in that case, the in-memory refcount information
4095 * will probably differ from the on-disk information which makes the BDS
4098 goto fail_broken_refcounts
;
4101 BLKDBG_EVENT(bs
->file
, BLKDBG_L1_UPDATE
);
4102 BLKDBG_EVENT(bs
->file
, BLKDBG_REFTABLE_UPDATE
);
4104 /* "Create" an empty reftable (one cluster) directly after the image
4105 * header and an empty L1 table three clusters after the image header;
4106 * the cluster between those two will be used as the first refblock */
4107 l1_ofs_rt_ofs_cls
.l1_offset
= cpu_to_be64(3 * s
->cluster_size
);
4108 l1_ofs_rt_ofs_cls
.reftable_offset
= cpu_to_be64(s
->cluster_size
);
4109 l1_ofs_rt_ofs_cls
.reftable_clusters
= cpu_to_be32(1);
4110 ret
= bdrv_pwrite_sync(bs
->file
, offsetof(QCowHeader
, l1_table_offset
),
4111 &l1_ofs_rt_ofs_cls
, sizeof(l1_ofs_rt_ofs_cls
));
4113 goto fail_broken_refcounts
;
4116 s
->l1_table_offset
= 3 * s
->cluster_size
;
4118 new_reftable
= g_try_new0(uint64_t, s
->cluster_size
/ sizeof(uint64_t));
4119 if (!new_reftable
) {
4121 goto fail_broken_refcounts
;
4124 s
->refcount_table_offset
= s
->cluster_size
;
4125 s
->refcount_table_size
= s
->cluster_size
/ sizeof(uint64_t);
4126 s
->max_refcount_table_index
= 0;
4128 g_free(s
->refcount_table
);
4129 s
->refcount_table
= new_reftable
;
4130 new_reftable
= NULL
;
4132 /* Now the in-memory refcount information again corresponds to the on-disk
4133 * information (reftable is empty and no refblocks (the refblock cache is
4134 * empty)); however, this means some clusters (e.g. the image header) are
4135 * referenced, but not refcounted, but the normal qcow2 code assumes that
4136 * the in-memory information is always correct */
4138 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_ALLOC
);
4140 /* Enter the first refblock into the reftable */
4141 rt_entry
= cpu_to_be64(2 * s
->cluster_size
);
4142 ret
= bdrv_pwrite_sync(bs
->file
, s
->cluster_size
,
4143 &rt_entry
, sizeof(rt_entry
));
4145 goto fail_broken_refcounts
;
4147 s
->refcount_table
[0] = 2 * s
->cluster_size
;
4149 s
->free_cluster_index
= 0;
4150 assert(3 + l1_clusters
<= s
->refcount_block_size
);
4151 offset
= qcow2_alloc_clusters(bs
, 3 * s
->cluster_size
+ l1_size2
);
4154 goto fail_broken_refcounts
;
4155 } else if (offset
> 0) {
4156 error_report("First cluster in emptied image is in use");
4160 /* Now finally the in-memory information corresponds to the on-disk
4161 * structures and is correct */
4162 ret
= qcow2_mark_clean(bs
);
4167 ret
= bdrv_truncate(bs
->file
, (3 + l1_clusters
) * s
->cluster_size
,
4168 PREALLOC_MODE_OFF
, &local_err
);
4170 error_report_err(local_err
);
4176 fail_broken_refcounts
:
4177 /* The BDS is unusable at this point. If we wanted to make it usable, we
4178 * would have to call qcow2_refcount_close(), qcow2_refcount_init(),
4179 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
4180 * again. However, because the functions which could have caused this error
4181 * path to be taken are used by those functions as well, it's very likely
4182 * that that sequence will fail as well. Therefore, just eject the BDS. */
4186 g_free(new_reftable
);
4190 static int qcow2_make_empty(BlockDriverState
*bs
)
4192 BDRVQcow2State
*s
= bs
->opaque
;
4193 uint64_t offset
, end_offset
;
4194 int step
= QEMU_ALIGN_DOWN(INT_MAX
, s
->cluster_size
);
4195 int l1_clusters
, ret
= 0;
4197 l1_clusters
= DIV_ROUND_UP(s
->l1_size
, s
->cluster_size
/ sizeof(uint64_t));
4199 if (s
->qcow_version
>= 3 && !s
->snapshots
&& !s
->nb_bitmaps
&&
4200 3 + l1_clusters
<= s
->refcount_block_size
&&
4201 s
->crypt_method_header
!= QCOW_CRYPT_LUKS
) {
4202 /* The following function only works for qcow2 v3 images (it
4203 * requires the dirty flag) and only as long as there are no
4204 * features that reserve extra clusters (such as snapshots,
4205 * LUKS header, or persistent bitmaps), because it completely
4206 * empties the image. Furthermore, the L1 table and three
4207 * additional clusters (image header, refcount table, one
4208 * refcount block) have to fit inside one refcount block. */
4209 return make_completely_empty(bs
);
4212 /* This fallback code simply discards every active cluster; this is slow,
4213 * but works in all cases */
4214 end_offset
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
4215 for (offset
= 0; offset
< end_offset
; offset
+= step
) {
4216 /* As this function is generally used after committing an external
4217 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
4218 * default action for this kind of discard is to pass the discard,
4219 * which will ideally result in an actually smaller image file, as
4220 * is probably desired. */
4221 ret
= qcow2_cluster_discard(bs
, offset
, MIN(step
, end_offset
- offset
),
4222 QCOW2_DISCARD_SNAPSHOT
, true);
4231 static coroutine_fn
int qcow2_co_flush_to_os(BlockDriverState
*bs
)
4233 BDRVQcow2State
*s
= bs
->opaque
;
4236 qemu_co_mutex_lock(&s
->lock
);
4237 ret
= qcow2_write_caches(bs
);
4238 qemu_co_mutex_unlock(&s
->lock
);
4243 static ssize_t
qcow2_measure_crypto_hdr_init_func(QCryptoBlock
*block
,
4244 size_t headerlen
, void *opaque
, Error
**errp
)
4246 size_t *headerlenp
= opaque
;
4248 /* Stash away the payload size */
4249 *headerlenp
= headerlen
;
4253 static ssize_t
qcow2_measure_crypto_hdr_write_func(QCryptoBlock
*block
,
4254 size_t offset
, const uint8_t *buf
, size_t buflen
,
4255 void *opaque
, Error
**errp
)
4257 /* Discard the bytes, we're not actually writing to an image */
4261 /* Determine the number of bytes for the LUKS payload */
4262 static bool qcow2_measure_luks_headerlen(QemuOpts
*opts
, size_t *len
,
4266 QDict
*cryptoopts_qdict
;
4267 QCryptoBlockCreateOptions
*cryptoopts
;
4268 QCryptoBlock
*crypto
;
4270 /* Extract "encrypt." options into a qdict */
4271 opts_qdict
= qemu_opts_to_qdict(opts
, NULL
);
4272 qdict_extract_subqdict(opts_qdict
, &cryptoopts_qdict
, "encrypt.");
4273 qobject_unref(opts_qdict
);
4275 /* Build QCryptoBlockCreateOptions object from qdict */
4276 qdict_put_str(cryptoopts_qdict
, "format", "luks");
4277 cryptoopts
= block_crypto_create_opts_init(cryptoopts_qdict
, errp
);
4278 qobject_unref(cryptoopts_qdict
);
4283 /* Fake LUKS creation in order to determine the payload size */
4284 crypto
= qcrypto_block_create(cryptoopts
, "encrypt.",
4285 qcow2_measure_crypto_hdr_init_func
,
4286 qcow2_measure_crypto_hdr_write_func
,
4288 qapi_free_QCryptoBlockCreateOptions(cryptoopts
);
4293 qcrypto_block_free(crypto
);
4297 static BlockMeasureInfo
*qcow2_measure(QemuOpts
*opts
, BlockDriverState
*in_bs
,
4300 Error
*local_err
= NULL
;
4301 BlockMeasureInfo
*info
;
4302 uint64_t required
= 0; /* bytes that contribute to required size */
4303 uint64_t virtual_size
; /* disk size as seen by guest */
4304 uint64_t refcount_bits
;
4306 uint64_t luks_payload_size
= 0;
4307 size_t cluster_size
;
4310 PreallocMode prealloc
;
4311 bool has_backing_file
;
4314 /* Parse image creation options */
4315 cluster_size
= qcow2_opt_get_cluster_size_del(opts
, &local_err
);
4320 version
= qcow2_opt_get_version_del(opts
, &local_err
);
4325 refcount_bits
= qcow2_opt_get_refcount_bits_del(opts
, version
, &local_err
);
4330 optstr
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
4331 prealloc
= qapi_enum_parse(&PreallocMode_lookup
, optstr
,
4332 PREALLOC_MODE_OFF
, &local_err
);
4338 optstr
= qemu_opt_get_del(opts
, BLOCK_OPT_BACKING_FILE
);
4339 has_backing_file
= !!optstr
;
4342 optstr
= qemu_opt_get_del(opts
, BLOCK_OPT_ENCRYPT_FORMAT
);
4343 has_luks
= optstr
&& strcmp(optstr
, "luks") == 0;
4349 if (!qcow2_measure_luks_headerlen(opts
, &headerlen
, &local_err
)) {
4353 luks_payload_size
= ROUND_UP(headerlen
, cluster_size
);
4356 virtual_size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0);
4357 virtual_size
= ROUND_UP(virtual_size
, cluster_size
);
4359 /* Check that virtual disk size is valid */
4360 l2_tables
= DIV_ROUND_UP(virtual_size
/ cluster_size
,
4361 cluster_size
/ sizeof(uint64_t));
4362 if (l2_tables
* sizeof(uint64_t) > QCOW_MAX_L1_SIZE
) {
4363 error_setg(&local_err
, "The image size is too large "
4364 "(try using a larger cluster size)");
4368 /* Account for input image */
4370 int64_t ssize
= bdrv_getlength(in_bs
);
4372 error_setg_errno(&local_err
, -ssize
,
4373 "Unable to get image virtual_size");
4377 virtual_size
= ROUND_UP(ssize
, cluster_size
);
4379 if (has_backing_file
) {
4380 /* We don't how much of the backing chain is shared by the input
4381 * image and the new image file. In the worst case the new image's
4382 * backing file has nothing in common with the input image. Be
4383 * conservative and assume all clusters need to be written.
4385 required
= virtual_size
;
4390 for (offset
= 0; offset
< ssize
; offset
+= pnum
) {
4393 ret
= bdrv_block_status_above(in_bs
, NULL
, offset
,
4394 ssize
- offset
, &pnum
, NULL
,
4397 error_setg_errno(&local_err
, -ret
,
4398 "Unable to get block status");
4402 if (ret
& BDRV_BLOCK_ZERO
) {
4403 /* Skip zero regions (safe with no backing file) */
4404 } else if ((ret
& (BDRV_BLOCK_DATA
| BDRV_BLOCK_ALLOCATED
)) ==
4405 (BDRV_BLOCK_DATA
| BDRV_BLOCK_ALLOCATED
)) {
4406 /* Extend pnum to end of cluster for next iteration */
4407 pnum
= ROUND_UP(offset
+ pnum
, cluster_size
) - offset
;
4409 /* Count clusters we've seen */
4410 required
+= offset
% cluster_size
+ pnum
;
4416 /* Take into account preallocation. Nothing special is needed for
4417 * PREALLOC_MODE_METADATA since metadata is always counted.
4419 if (prealloc
== PREALLOC_MODE_FULL
|| prealloc
== PREALLOC_MODE_FALLOC
) {
4420 required
= virtual_size
;
4423 info
= g_new(BlockMeasureInfo
, 1);
4424 info
->fully_allocated
=
4425 qcow2_calc_prealloc_size(virtual_size
, cluster_size
,
4426 ctz32(refcount_bits
)) + luks_payload_size
;
4428 /* Remove data clusters that are not required. This overestimates the
4429 * required size because metadata needed for the fully allocated file is
4432 info
->required
= info
->fully_allocated
- virtual_size
+ required
;
4436 error_propagate(errp
, local_err
);
4440 static int qcow2_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
4442 BDRVQcow2State
*s
= bs
->opaque
;
4443 bdi
->unallocated_blocks_are_zero
= true;
4444 bdi
->cluster_size
= s
->cluster_size
;
4445 bdi
->vm_state_offset
= qcow2_vm_state_offset(s
);
4449 static ImageInfoSpecific
*qcow2_get_specific_info(BlockDriverState
*bs
,
4452 BDRVQcow2State
*s
= bs
->opaque
;
4453 ImageInfoSpecific
*spec_info
;
4454 QCryptoBlockInfo
*encrypt_info
= NULL
;
4455 Error
*local_err
= NULL
;
4457 if (s
->crypto
!= NULL
) {
4458 encrypt_info
= qcrypto_block_get_info(s
->crypto
, &local_err
);
4460 error_propagate(errp
, local_err
);
4465 spec_info
= g_new(ImageInfoSpecific
, 1);
4466 *spec_info
= (ImageInfoSpecific
){
4467 .type
= IMAGE_INFO_SPECIFIC_KIND_QCOW2
,
4468 .u
.qcow2
.data
= g_new0(ImageInfoSpecificQCow2
, 1),
4470 if (s
->qcow_version
== 2) {
4471 *spec_info
->u
.qcow2
.data
= (ImageInfoSpecificQCow2
){
4472 .compat
= g_strdup("0.10"),
4473 .refcount_bits
= s
->refcount_bits
,
4475 } else if (s
->qcow_version
== 3) {
4476 Qcow2BitmapInfoList
*bitmaps
;
4477 bitmaps
= qcow2_get_bitmap_info_list(bs
, &local_err
);
4479 error_propagate(errp
, local_err
);
4480 qapi_free_ImageInfoSpecific(spec_info
);
4483 *spec_info
->u
.qcow2
.data
= (ImageInfoSpecificQCow2
){
4484 .compat
= g_strdup("1.1"),
4485 .lazy_refcounts
= s
->compatible_features
&
4486 QCOW2_COMPAT_LAZY_REFCOUNTS
,
4487 .has_lazy_refcounts
= true,
4488 .corrupt
= s
->incompatible_features
&
4489 QCOW2_INCOMPAT_CORRUPT
,
4490 .has_corrupt
= true,
4491 .refcount_bits
= s
->refcount_bits
,
4492 .has_bitmaps
= !!bitmaps
,
4496 /* if this assertion fails, this probably means a new version was
4497 * added without having it covered here */
4502 ImageInfoSpecificQCow2Encryption
*qencrypt
=
4503 g_new(ImageInfoSpecificQCow2Encryption
, 1);
4504 switch (encrypt_info
->format
) {
4505 case Q_CRYPTO_BLOCK_FORMAT_QCOW
:
4506 qencrypt
->format
= BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES
;
4508 case Q_CRYPTO_BLOCK_FORMAT_LUKS
:
4509 qencrypt
->format
= BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS
;
4510 qencrypt
->u
.luks
= encrypt_info
->u
.luks
;
4515 /* Since we did shallow copy above, erase any pointers
4516 * in the original info */
4517 memset(&encrypt_info
->u
, 0, sizeof(encrypt_info
->u
));
4518 qapi_free_QCryptoBlockInfo(encrypt_info
);
4520 spec_info
->u
.qcow2
.data
->has_encrypt
= true;
4521 spec_info
->u
.qcow2
.data
->encrypt
= qencrypt
;
4527 static int qcow2_save_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
4530 BDRVQcow2State
*s
= bs
->opaque
;
4532 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_SAVE
);
4533 return bs
->drv
->bdrv_co_pwritev(bs
, qcow2_vm_state_offset(s
) + pos
,
4534 qiov
->size
, qiov
, 0);
4537 static int qcow2_load_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
4540 BDRVQcow2State
*s
= bs
->opaque
;
4542 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_LOAD
);
4543 return bs
->drv
->bdrv_co_preadv(bs
, qcow2_vm_state_offset(s
) + pos
,
4544 qiov
->size
, qiov
, 0);
4548 * Downgrades an image's version. To achieve this, any incompatible features
4549 * have to be removed.
4551 static int qcow2_downgrade(BlockDriverState
*bs
, int target_version
,
4552 BlockDriverAmendStatusCB
*status_cb
, void *cb_opaque
,
4555 BDRVQcow2State
*s
= bs
->opaque
;
4556 int current_version
= s
->qcow_version
;
4559 /* This is qcow2_downgrade(), not qcow2_upgrade() */
4560 assert(target_version
< current_version
);
4562 /* There are no other versions (now) that you can downgrade to */
4563 assert(target_version
== 2);
4565 if (s
->refcount_order
!= 4) {
4566 error_setg(errp
, "compat=0.10 requires refcount_bits=16");
4570 /* clear incompatible features */
4571 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
4572 ret
= qcow2_mark_clean(bs
);
4574 error_setg_errno(errp
, -ret
, "Failed to make the image clean");
4579 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
4580 * the first place; if that happens nonetheless, returning -ENOTSUP is the
4581 * best thing to do anyway */
4583 if (s
->incompatible_features
) {
4584 error_setg(errp
, "Cannot downgrade an image with incompatible features "
4585 "%#" PRIx64
" set", s
->incompatible_features
);
4589 /* since we can ignore compatible features, we can set them to 0 as well */
4590 s
->compatible_features
= 0;
4591 /* if lazy refcounts have been used, they have already been fixed through
4592 * clearing the dirty flag */
4594 /* clearing autoclear features is trivial */
4595 s
->autoclear_features
= 0;
4597 ret
= qcow2_expand_zero_clusters(bs
, status_cb
, cb_opaque
);
4599 error_setg_errno(errp
, -ret
, "Failed to turn zero into data clusters");
4603 s
->qcow_version
= target_version
;
4604 ret
= qcow2_update_header(bs
);
4606 s
->qcow_version
= current_version
;
4607 error_setg_errno(errp
, -ret
, "Failed to update the image header");
4613 typedef enum Qcow2AmendOperation
{
4614 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be
4615 * statically initialized to so that the helper CB can discern the first
4616 * invocation from an operation change */
4617 QCOW2_NO_OPERATION
= 0,
4619 QCOW2_CHANGING_REFCOUNT_ORDER
,
4621 } Qcow2AmendOperation
;
4623 typedef struct Qcow2AmendHelperCBInfo
{
4624 /* The code coordinating the amend operations should only modify
4625 * these four fields; the rest will be managed by the CB */
4626 BlockDriverAmendStatusCB
*original_status_cb
;
4627 void *original_cb_opaque
;
4629 Qcow2AmendOperation current_operation
;
4631 /* Total number of operations to perform (only set once) */
4632 int total_operations
;
4634 /* The following fields are managed by the CB */
4636 /* Number of operations completed */
4637 int operations_completed
;
4639 /* Cumulative offset of all completed operations */
4640 int64_t offset_completed
;
4642 Qcow2AmendOperation last_operation
;
4643 int64_t last_work_size
;
4644 } Qcow2AmendHelperCBInfo
;
4646 static void qcow2_amend_helper_cb(BlockDriverState
*bs
,
4647 int64_t operation_offset
,
4648 int64_t operation_work_size
, void *opaque
)
4650 Qcow2AmendHelperCBInfo
*info
= opaque
;
4651 int64_t current_work_size
;
4652 int64_t projected_work_size
;
4654 if (info
->current_operation
!= info
->last_operation
) {
4655 if (info
->last_operation
!= QCOW2_NO_OPERATION
) {
4656 info
->offset_completed
+= info
->last_work_size
;
4657 info
->operations_completed
++;
4660 info
->last_operation
= info
->current_operation
;
4663 assert(info
->total_operations
> 0);
4664 assert(info
->operations_completed
< info
->total_operations
);
4666 info
->last_work_size
= operation_work_size
;
4668 current_work_size
= info
->offset_completed
+ operation_work_size
;
4670 /* current_work_size is the total work size for (operations_completed + 1)
4671 * operations (which includes this one), so multiply it by the number of
4672 * operations not covered and divide it by the number of operations
4673 * covered to get a projection for the operations not covered */
4674 projected_work_size
= current_work_size
* (info
->total_operations
-
4675 info
->operations_completed
- 1)
4676 / (info
->operations_completed
+ 1);
4678 info
->original_status_cb(bs
, info
->offset_completed
+ operation_offset
,
4679 current_work_size
+ projected_work_size
,
4680 info
->original_cb_opaque
);
4683 static int qcow2_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
,
4684 BlockDriverAmendStatusCB
*status_cb
,
4688 BDRVQcow2State
*s
= bs
->opaque
;
4689 int old_version
= s
->qcow_version
, new_version
= old_version
;
4690 uint64_t new_size
= 0;
4691 const char *backing_file
= NULL
, *backing_format
= NULL
;
4692 bool lazy_refcounts
= s
->use_lazy_refcounts
;
4693 const char *compat
= NULL
;
4694 uint64_t cluster_size
= s
->cluster_size
;
4697 int refcount_bits
= s
->refcount_bits
;
4699 QemuOptDesc
*desc
= opts
->list
->desc
;
4700 Qcow2AmendHelperCBInfo helper_cb_info
;
4702 while (desc
&& desc
->name
) {
4703 if (!qemu_opt_find(opts
, desc
->name
)) {
4704 /* only change explicitly defined options */
4709 if (!strcmp(desc
->name
, BLOCK_OPT_COMPAT_LEVEL
)) {
4710 compat
= qemu_opt_get(opts
, BLOCK_OPT_COMPAT_LEVEL
);
4712 /* preserve default */
4713 } else if (!strcmp(compat
, "0.10")) {
4715 } else if (!strcmp(compat
, "1.1")) {
4718 error_setg(errp
, "Unknown compatibility level %s", compat
);
4721 } else if (!strcmp(desc
->name
, BLOCK_OPT_PREALLOC
)) {
4722 error_setg(errp
, "Cannot change preallocation mode");
4724 } else if (!strcmp(desc
->name
, BLOCK_OPT_SIZE
)) {
4725 new_size
= qemu_opt_get_size(opts
, BLOCK_OPT_SIZE
, 0);
4726 } else if (!strcmp(desc
->name
, BLOCK_OPT_BACKING_FILE
)) {
4727 backing_file
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FILE
);
4728 } else if (!strcmp(desc
->name
, BLOCK_OPT_BACKING_FMT
)) {
4729 backing_format
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FMT
);
4730 } else if (!strcmp(desc
->name
, BLOCK_OPT_ENCRYPT
)) {
4731 encrypt
= qemu_opt_get_bool(opts
, BLOCK_OPT_ENCRYPT
,
4734 if (encrypt
!= !!s
->crypto
) {
4736 "Changing the encryption flag is not supported");
4739 } else if (!strcmp(desc
->name
, BLOCK_OPT_ENCRYPT_FORMAT
)) {
4740 encformat
= qcow2_crypt_method_from_format(
4741 qemu_opt_get(opts
, BLOCK_OPT_ENCRYPT_FORMAT
));
4743 if (encformat
!= s
->crypt_method_header
) {
4745 "Changing the encryption format is not supported");
4748 } else if (g_str_has_prefix(desc
->name
, "encrypt.")) {
4750 "Changing the encryption parameters is not supported");
4752 } else if (!strcmp(desc
->name
, BLOCK_OPT_CLUSTER_SIZE
)) {
4753 cluster_size
= qemu_opt_get_size(opts
, BLOCK_OPT_CLUSTER_SIZE
,
4755 if (cluster_size
!= s
->cluster_size
) {
4756 error_setg(errp
, "Changing the cluster size is not supported");
4759 } else if (!strcmp(desc
->name
, BLOCK_OPT_LAZY_REFCOUNTS
)) {
4760 lazy_refcounts
= qemu_opt_get_bool(opts
, BLOCK_OPT_LAZY_REFCOUNTS
,
4762 } else if (!strcmp(desc
->name
, BLOCK_OPT_REFCOUNT_BITS
)) {
4763 refcount_bits
= qemu_opt_get_number(opts
, BLOCK_OPT_REFCOUNT_BITS
,
4766 if (refcount_bits
<= 0 || refcount_bits
> 64 ||
4767 !is_power_of_2(refcount_bits
))
4769 error_setg(errp
, "Refcount width must be a power of two and "
4770 "may not exceed 64 bits");
4774 /* if this point is reached, this probably means a new option was
4775 * added without having it covered here */
4782 helper_cb_info
= (Qcow2AmendHelperCBInfo
){
4783 .original_status_cb
= status_cb
,
4784 .original_cb_opaque
= cb_opaque
,
4785 .total_operations
= (new_version
< old_version
)
4786 + (s
->refcount_bits
!= refcount_bits
)
4789 /* Upgrade first (some features may require compat=1.1) */
4790 if (new_version
> old_version
) {
4791 s
->qcow_version
= new_version
;
4792 ret
= qcow2_update_header(bs
);
4794 s
->qcow_version
= old_version
;
4795 error_setg_errno(errp
, -ret
, "Failed to update the image header");
4800 if (s
->refcount_bits
!= refcount_bits
) {
4801 int refcount_order
= ctz32(refcount_bits
);
4803 if (new_version
< 3 && refcount_bits
!= 16) {
4804 error_setg(errp
, "Refcount widths other than 16 bits require "
4805 "compatibility level 1.1 or above (use compat=1.1 or "
4810 helper_cb_info
.current_operation
= QCOW2_CHANGING_REFCOUNT_ORDER
;
4811 ret
= qcow2_change_refcount_order(bs
, refcount_order
,
4812 &qcow2_amend_helper_cb
,
4813 &helper_cb_info
, errp
);
4819 if (backing_file
|| backing_format
) {
4820 ret
= qcow2_change_backing_file(bs
,
4821 backing_file
?: s
->image_backing_file
,
4822 backing_format
?: s
->image_backing_format
);
4824 error_setg_errno(errp
, -ret
, "Failed to change the backing file");
4829 if (s
->use_lazy_refcounts
!= lazy_refcounts
) {
4830 if (lazy_refcounts
) {
4831 if (new_version
< 3) {
4832 error_setg(errp
, "Lazy refcounts only supported with "
4833 "compatibility level 1.1 and above (use compat=1.1 "
4837 s
->compatible_features
|= QCOW2_COMPAT_LAZY_REFCOUNTS
;
4838 ret
= qcow2_update_header(bs
);
4840 s
->compatible_features
&= ~QCOW2_COMPAT_LAZY_REFCOUNTS
;
4841 error_setg_errno(errp
, -ret
, "Failed to update the image header");
4844 s
->use_lazy_refcounts
= true;
4846 /* make image clean first */
4847 ret
= qcow2_mark_clean(bs
);
4849 error_setg_errno(errp
, -ret
, "Failed to make the image clean");
4852 /* now disallow lazy refcounts */
4853 s
->compatible_features
&= ~QCOW2_COMPAT_LAZY_REFCOUNTS
;
4854 ret
= qcow2_update_header(bs
);
4856 s
->compatible_features
|= QCOW2_COMPAT_LAZY_REFCOUNTS
;
4857 error_setg_errno(errp
, -ret
, "Failed to update the image header");
4860 s
->use_lazy_refcounts
= false;
4865 BlockBackend
*blk
= blk_new(BLK_PERM_RESIZE
, BLK_PERM_ALL
);
4866 ret
= blk_insert_bs(blk
, bs
, errp
);
4872 ret
= blk_truncate(blk
, new_size
, PREALLOC_MODE_OFF
, errp
);
4879 /* Downgrade last (so unsupported features can be removed before) */
4880 if (new_version
< old_version
) {
4881 helper_cb_info
.current_operation
= QCOW2_DOWNGRADING
;
4882 ret
= qcow2_downgrade(bs
, new_version
, &qcow2_amend_helper_cb
,
4883 &helper_cb_info
, errp
);
4893 * If offset or size are negative, respectively, they will not be included in
4894 * the BLOCK_IMAGE_CORRUPTED event emitted.
4895 * fatal will be ignored for read-only BDS; corruptions found there will always
4896 * be considered non-fatal.
4898 void qcow2_signal_corruption(BlockDriverState
*bs
, bool fatal
, int64_t offset
,
4899 int64_t size
, const char *message_format
, ...)
4901 BDRVQcow2State
*s
= bs
->opaque
;
4902 const char *node_name
;
4906 fatal
= fatal
&& bdrv_is_writable(bs
);
4908 if (s
->signaled_corruption
&&
4909 (!fatal
|| (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
)))
4914 va_start(ap
, message_format
);
4915 message
= g_strdup_vprintf(message_format
, ap
);
4919 fprintf(stderr
, "qcow2: Marking image as corrupt: %s; further "
4920 "corruption events will be suppressed\n", message
);
4922 fprintf(stderr
, "qcow2: Image is corrupt: %s; further non-fatal "
4923 "corruption events will be suppressed\n", message
);
4926 node_name
= bdrv_get_node_name(bs
);
4927 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs
),
4928 *node_name
!= '\0', node_name
,
4929 message
, offset
>= 0, offset
,
4935 qcow2_mark_corrupt(bs
);
4936 bs
->drv
= NULL
; /* make BDS unusable */
4939 s
->signaled_corruption
= true;
4942 static QemuOptsList qcow2_create_opts
= {
4943 .name
= "qcow2-create-opts",
4944 .head
= QTAILQ_HEAD_INITIALIZER(qcow2_create_opts
.head
),
4947 .name
= BLOCK_OPT_SIZE
,
4948 .type
= QEMU_OPT_SIZE
,
4949 .help
= "Virtual disk size"
4952 .name
= BLOCK_OPT_COMPAT_LEVEL
,
4953 .type
= QEMU_OPT_STRING
,
4954 .help
= "Compatibility level (0.10 or 1.1)"
4957 .name
= BLOCK_OPT_BACKING_FILE
,
4958 .type
= QEMU_OPT_STRING
,
4959 .help
= "File name of a base image"
4962 .name
= BLOCK_OPT_BACKING_FMT
,
4963 .type
= QEMU_OPT_STRING
,
4964 .help
= "Image format of the base image"
4967 .name
= BLOCK_OPT_ENCRYPT
,
4968 .type
= QEMU_OPT_BOOL
,
4969 .help
= "Encrypt the image with format 'aes'. (Deprecated "
4970 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT
"=aes)",
4973 .name
= BLOCK_OPT_ENCRYPT_FORMAT
,
4974 .type
= QEMU_OPT_STRING
,
4975 .help
= "Encrypt the image, format choices: 'aes', 'luks'",
4977 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.",
4978 "ID of secret providing qcow AES key or LUKS passphrase"),
4979 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."),
4980 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."),
4981 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."),
4982 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."),
4983 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."),
4984 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."),
4986 .name
= BLOCK_OPT_CLUSTER_SIZE
,
4987 .type
= QEMU_OPT_SIZE
,
4988 .help
= "qcow2 cluster size",
4989 .def_value_str
= stringify(DEFAULT_CLUSTER_SIZE
)
4992 .name
= BLOCK_OPT_PREALLOC
,
4993 .type
= QEMU_OPT_STRING
,
4994 .help
= "Preallocation mode (allowed values: off, metadata, "
4998 .name
= BLOCK_OPT_LAZY_REFCOUNTS
,
4999 .type
= QEMU_OPT_BOOL
,
5000 .help
= "Postpone refcount updates",
5001 .def_value_str
= "off"
5004 .name
= BLOCK_OPT_REFCOUNT_BITS
,
5005 .type
= QEMU_OPT_NUMBER
,
5006 .help
= "Width of a reference count entry in bits",
5007 .def_value_str
= "16"
5009 { /* end of list */ }
5013 static const char *const qcow2_strong_runtime_opts
[] = {
5014 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET
,
5019 BlockDriver bdrv_qcow2
= {
5020 .format_name
= "qcow2",
5021 .instance_size
= sizeof(BDRVQcow2State
),
5022 .bdrv_probe
= qcow2_probe
,
5023 .bdrv_open
= qcow2_open
,
5024 .bdrv_close
= qcow2_close
,
5025 .bdrv_reopen_prepare
= qcow2_reopen_prepare
,
5026 .bdrv_reopen_commit
= qcow2_reopen_commit
,
5027 .bdrv_reopen_abort
= qcow2_reopen_abort
,
5028 .bdrv_join_options
= qcow2_join_options
,
5029 .bdrv_child_perm
= bdrv_format_default_perms
,
5030 .bdrv_co_create_opts
= qcow2_co_create_opts
,
5031 .bdrv_co_create
= qcow2_co_create
,
5032 .bdrv_has_zero_init
= bdrv_has_zero_init_1
,
5033 .bdrv_co_block_status
= qcow2_co_block_status
,
5035 .bdrv_co_preadv
= qcow2_co_preadv
,
5036 .bdrv_co_pwritev
= qcow2_co_pwritev
,
5037 .bdrv_co_flush_to_os
= qcow2_co_flush_to_os
,
5039 .bdrv_co_pwrite_zeroes
= qcow2_co_pwrite_zeroes
,
5040 .bdrv_co_pdiscard
= qcow2_co_pdiscard
,
5041 .bdrv_co_copy_range_from
= qcow2_co_copy_range_from
,
5042 .bdrv_co_copy_range_to
= qcow2_co_copy_range_to
,
5043 .bdrv_co_truncate
= qcow2_co_truncate
,
5044 .bdrv_co_pwritev_compressed
= qcow2_co_pwritev_compressed
,
5045 .bdrv_make_empty
= qcow2_make_empty
,
5047 .bdrv_snapshot_create
= qcow2_snapshot_create
,
5048 .bdrv_snapshot_goto
= qcow2_snapshot_goto
,
5049 .bdrv_snapshot_delete
= qcow2_snapshot_delete
,
5050 .bdrv_snapshot_list
= qcow2_snapshot_list
,
5051 .bdrv_snapshot_load_tmp
= qcow2_snapshot_load_tmp
,
5052 .bdrv_measure
= qcow2_measure
,
5053 .bdrv_get_info
= qcow2_get_info
,
5054 .bdrv_get_specific_info
= qcow2_get_specific_info
,
5056 .bdrv_save_vmstate
= qcow2_save_vmstate
,
5057 .bdrv_load_vmstate
= qcow2_load_vmstate
,
5059 .supports_backing
= true,
5060 .bdrv_change_backing_file
= qcow2_change_backing_file
,
5062 .bdrv_refresh_limits
= qcow2_refresh_limits
,
5063 .bdrv_co_invalidate_cache
= qcow2_co_invalidate_cache
,
5064 .bdrv_inactivate
= qcow2_inactivate
,
5066 .create_opts
= &qcow2_create_opts
,
5067 .strong_runtime_opts
= qcow2_strong_runtime_opts
,
5068 .bdrv_co_check
= qcow2_co_check
,
5069 .bdrv_amend_options
= qcow2_amend_options
,
5071 .bdrv_detach_aio_context
= qcow2_detach_aio_context
,
5072 .bdrv_attach_aio_context
= qcow2_attach_aio_context
,
5074 .bdrv_reopen_bitmaps_rw
= qcow2_reopen_bitmaps_rw
,
5075 .bdrv_can_store_new_dirty_bitmap
= qcow2_can_store_new_dirty_bitmap
,
5076 .bdrv_remove_persistent_dirty_bitmap
= qcow2_remove_persistent_dirty_bitmap
,
5079 static void bdrv_qcow2_init(void)
5081 bdrv_register(&bdrv_qcow2
);
5084 block_init(bdrv_qcow2_init
);