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"
27 #include "block/qdict.h"
28 #include "sysemu/block-backend.h"
29 #include "qemu/main-loop.h"
30 #include "qemu/module.h"
32 #include "qemu/error-report.h"
33 #include "qapi/error.h"
34 #include "qapi/qapi-events-block-core.h"
35 #include "qapi/qmp/qdict.h"
36 #include "qapi/qmp/qstring.h"
38 #include "qemu/option_int.h"
39 #include "qemu/cutils.h"
40 #include "qemu/bswap.h"
41 #include "qapi/qobject-input-visitor.h"
42 #include "qapi/qapi-visit-block-core.h"
44 #include "block/aio_task.h"
47 Differences with QCOW:
49 - Support for multiple incremental snapshots.
50 - Memory management by reference counts.
51 - Clusters which have a reference count of one have the bit
52 QCOW_OFLAG_COPIED to optimize write performance.
53 - Size of compressed clusters is stored in sectors to reduce bit usage
54 in the cluster offsets.
55 - Support for storing additional data (such as the VM state) in the
57 - If a backing store is used, the cluster size is not constrained
58 (could be backported to QCOW).
59 - L2 tables have always a size of one cluster.
66 } QEMU_PACKED QCowExtension
;
68 #define QCOW2_EXT_MAGIC_END 0
69 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
70 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
71 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77
72 #define QCOW2_EXT_MAGIC_BITMAPS 0x23852875
73 #define QCOW2_EXT_MAGIC_DATA_FILE 0x44415441
75 static int coroutine_fn
76 qcow2_co_preadv_compressed(BlockDriverState
*bs
,
77 uint64_t file_cluster_offset
,
83 static int qcow2_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
85 const QCowHeader
*cow_header
= (const void *)buf
;
87 if (buf_size
>= sizeof(QCowHeader
) &&
88 be32_to_cpu(cow_header
->magic
) == QCOW_MAGIC
&&
89 be32_to_cpu(cow_header
->version
) >= 2)
96 static ssize_t
qcow2_crypto_hdr_read_func(QCryptoBlock
*block
, size_t offset
,
97 uint8_t *buf
, size_t buflen
,
98 void *opaque
, Error
**errp
)
100 BlockDriverState
*bs
= opaque
;
101 BDRVQcow2State
*s
= bs
->opaque
;
104 if ((offset
+ buflen
) > s
->crypto_header
.length
) {
105 error_setg(errp
, "Request for data outside of extension header");
109 ret
= bdrv_pread(bs
->file
,
110 s
->crypto_header
.offset
+ offset
, buf
, buflen
);
112 error_setg_errno(errp
, -ret
, "Could not read encryption header");
119 static ssize_t
qcow2_crypto_hdr_init_func(QCryptoBlock
*block
, size_t headerlen
,
120 void *opaque
, Error
**errp
)
122 BlockDriverState
*bs
= opaque
;
123 BDRVQcow2State
*s
= bs
->opaque
;
127 ret
= qcow2_alloc_clusters(bs
, headerlen
);
129 error_setg_errno(errp
, -ret
,
130 "Cannot allocate cluster for LUKS header size %zu",
135 s
->crypto_header
.length
= headerlen
;
136 s
->crypto_header
.offset
= ret
;
139 * Zero fill all space in cluster so it has predictable
140 * content, as we may not initialize some regions of the
141 * header (eg only 1 out of 8 key slots will be initialized)
143 clusterlen
= size_to_clusters(s
, headerlen
) * s
->cluster_size
;
144 assert(qcow2_pre_write_overlap_check(bs
, 0, ret
, clusterlen
, false) == 0);
145 ret
= bdrv_pwrite_zeroes(bs
->file
,
149 error_setg_errno(errp
, -ret
, "Could not zero fill encryption header");
157 static ssize_t
qcow2_crypto_hdr_write_func(QCryptoBlock
*block
, size_t offset
,
158 const uint8_t *buf
, size_t buflen
,
159 void *opaque
, Error
**errp
)
161 BlockDriverState
*bs
= opaque
;
162 BDRVQcow2State
*s
= bs
->opaque
;
165 if ((offset
+ buflen
) > s
->crypto_header
.length
) {
166 error_setg(errp
, "Request for data outside of extension header");
170 ret
= bdrv_pwrite(bs
->file
,
171 s
->crypto_header
.offset
+ offset
, buf
, buflen
);
173 error_setg_errno(errp
, -ret
, "Could not read encryption header");
181 * read qcow2 extension and fill bs
182 * start reading from start_offset
183 * finish reading upon magic of value 0 or when end_offset reached
184 * unknown magic is skipped (future extension this version knows nothing about)
185 * return 0 upon success, non-0 otherwise
187 static int qcow2_read_extensions(BlockDriverState
*bs
, uint64_t start_offset
,
188 uint64_t end_offset
, void **p_feature_table
,
189 int flags
, bool *need_update_header
,
192 BDRVQcow2State
*s
= bs
->opaque
;
196 Qcow2BitmapHeaderExt bitmaps_ext
;
198 if (need_update_header
!= NULL
) {
199 *need_update_header
= false;
203 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset
, end_offset
);
205 offset
= start_offset
;
206 while (offset
< end_offset
) {
210 if (offset
> s
->cluster_size
)
211 printf("qcow2_read_extension: suspicious offset %lu\n", offset
);
213 printf("attempting to read extended header in offset %lu\n", offset
);
216 ret
= bdrv_pread(bs
->file
, offset
, &ext
, sizeof(ext
));
218 error_setg_errno(errp
, -ret
, "qcow2_read_extension: ERROR: "
219 "pread fail from offset %" PRIu64
, offset
);
222 ext
.magic
= be32_to_cpu(ext
.magic
);
223 ext
.len
= be32_to_cpu(ext
.len
);
224 offset
+= sizeof(ext
);
226 printf("ext.magic = 0x%x\n", ext
.magic
);
228 if (offset
> end_offset
|| ext
.len
> end_offset
- offset
) {
229 error_setg(errp
, "Header extension too large");
234 case QCOW2_EXT_MAGIC_END
:
237 case QCOW2_EXT_MAGIC_BACKING_FORMAT
:
238 if (ext
.len
>= sizeof(bs
->backing_format
)) {
239 error_setg(errp
, "ERROR: ext_backing_format: len=%" PRIu32
240 " too large (>=%zu)", ext
.len
,
241 sizeof(bs
->backing_format
));
244 ret
= bdrv_pread(bs
->file
, offset
, bs
->backing_format
, ext
.len
);
246 error_setg_errno(errp
, -ret
, "ERROR: ext_backing_format: "
247 "Could not read format name");
250 bs
->backing_format
[ext
.len
] = '\0';
251 s
->image_backing_format
= g_strdup(bs
->backing_format
);
253 printf("Qcow2: Got format extension %s\n", bs
->backing_format
);
257 case QCOW2_EXT_MAGIC_FEATURE_TABLE
:
258 if (p_feature_table
!= NULL
) {
259 void* feature_table
= g_malloc0(ext
.len
+ 2 * sizeof(Qcow2Feature
));
260 ret
= bdrv_pread(bs
->file
, offset
, feature_table
, ext
.len
);
262 error_setg_errno(errp
, -ret
, "ERROR: ext_feature_table: "
263 "Could not read table");
267 *p_feature_table
= feature_table
;
271 case QCOW2_EXT_MAGIC_CRYPTO_HEADER
: {
272 unsigned int cflags
= 0;
273 if (s
->crypt_method_header
!= QCOW_CRYPT_LUKS
) {
274 error_setg(errp
, "CRYPTO header extension only "
275 "expected with LUKS encryption method");
278 if (ext
.len
!= sizeof(Qcow2CryptoHeaderExtension
)) {
279 error_setg(errp
, "CRYPTO header extension size %u, "
280 "but expected size %zu", ext
.len
,
281 sizeof(Qcow2CryptoHeaderExtension
));
285 ret
= bdrv_pread(bs
->file
, offset
, &s
->crypto_header
, ext
.len
);
287 error_setg_errno(errp
, -ret
,
288 "Unable to read CRYPTO header extension");
291 s
->crypto_header
.offset
= be64_to_cpu(s
->crypto_header
.offset
);
292 s
->crypto_header
.length
= be64_to_cpu(s
->crypto_header
.length
);
294 if ((s
->crypto_header
.offset
% s
->cluster_size
) != 0) {
295 error_setg(errp
, "Encryption header offset '%" PRIu64
"' is "
296 "not a multiple of cluster size '%u'",
297 s
->crypto_header
.offset
, s
->cluster_size
);
301 if (flags
& BDRV_O_NO_IO
) {
302 cflags
|= QCRYPTO_BLOCK_OPEN_NO_IO
;
304 s
->crypto
= qcrypto_block_open(s
->crypto_opts
, "encrypt.",
305 qcow2_crypto_hdr_read_func
,
306 bs
, cflags
, QCOW2_MAX_THREADS
, errp
);
312 case QCOW2_EXT_MAGIC_BITMAPS
:
313 if (ext
.len
!= sizeof(bitmaps_ext
)) {
314 error_setg_errno(errp
, -ret
, "bitmaps_ext: "
315 "Invalid extension length");
319 if (!(s
->autoclear_features
& QCOW2_AUTOCLEAR_BITMAPS
)) {
320 if (s
->qcow_version
< 3) {
321 /* Let's be a bit more specific */
322 warn_report("This qcow2 v2 image contains bitmaps, but "
323 "they may have been modified by a program "
324 "without persistent bitmap support; so now "
325 "they must all be considered inconsistent");
327 warn_report("a program lacking bitmap support "
328 "modified this file, so all bitmaps are now "
329 "considered inconsistent");
331 error_printf("Some clusters may be leaked, "
332 "run 'qemu-img check -r' on the image "
334 if (need_update_header
!= NULL
) {
335 /* Updating is needed to drop invalid bitmap extension. */
336 *need_update_header
= true;
341 ret
= bdrv_pread(bs
->file
, offset
, &bitmaps_ext
, ext
.len
);
343 error_setg_errno(errp
, -ret
, "bitmaps_ext: "
344 "Could not read ext header");
348 if (bitmaps_ext
.reserved32
!= 0) {
349 error_setg_errno(errp
, -ret
, "bitmaps_ext: "
350 "Reserved field is not zero");
354 bitmaps_ext
.nb_bitmaps
= be32_to_cpu(bitmaps_ext
.nb_bitmaps
);
355 bitmaps_ext
.bitmap_directory_size
=
356 be64_to_cpu(bitmaps_ext
.bitmap_directory_size
);
357 bitmaps_ext
.bitmap_directory_offset
=
358 be64_to_cpu(bitmaps_ext
.bitmap_directory_offset
);
360 if (bitmaps_ext
.nb_bitmaps
> QCOW2_MAX_BITMAPS
) {
362 "bitmaps_ext: Image has %" PRIu32
" bitmaps, "
363 "exceeding the QEMU supported maximum of %d",
364 bitmaps_ext
.nb_bitmaps
, QCOW2_MAX_BITMAPS
);
368 if (bitmaps_ext
.nb_bitmaps
== 0) {
369 error_setg(errp
, "found bitmaps extension with zero bitmaps");
373 if (offset_into_cluster(s
, bitmaps_ext
.bitmap_directory_offset
)) {
374 error_setg(errp
, "bitmaps_ext: "
375 "invalid bitmap directory offset");
379 if (bitmaps_ext
.bitmap_directory_size
>
380 QCOW2_MAX_BITMAP_DIRECTORY_SIZE
) {
381 error_setg(errp
, "bitmaps_ext: "
382 "bitmap directory size (%" PRIu64
") exceeds "
383 "the maximum supported size (%d)",
384 bitmaps_ext
.bitmap_directory_size
,
385 QCOW2_MAX_BITMAP_DIRECTORY_SIZE
);
389 s
->nb_bitmaps
= bitmaps_ext
.nb_bitmaps
;
390 s
->bitmap_directory_offset
=
391 bitmaps_ext
.bitmap_directory_offset
;
392 s
->bitmap_directory_size
=
393 bitmaps_ext
.bitmap_directory_size
;
396 printf("Qcow2: Got bitmaps extension: "
397 "offset=%" PRIu64
" nb_bitmaps=%" PRIu32
"\n",
398 s
->bitmap_directory_offset
, s
->nb_bitmaps
);
402 case QCOW2_EXT_MAGIC_DATA_FILE
:
404 s
->image_data_file
= g_malloc0(ext
.len
+ 1);
405 ret
= bdrv_pread(bs
->file
, offset
, s
->image_data_file
, ext
.len
);
407 error_setg_errno(errp
, -ret
,
408 "ERROR: Could not read data file name");
412 printf("Qcow2: Got external data file %s\n", s
->image_data_file
);
418 /* unknown magic - save it in case we need to rewrite the header */
419 /* If you add a new feature, make sure to also update the fast
420 * path of qcow2_make_empty() to deal with it. */
422 Qcow2UnknownHeaderExtension
*uext
;
424 uext
= g_malloc0(sizeof(*uext
) + ext
.len
);
425 uext
->magic
= ext
.magic
;
427 QLIST_INSERT_HEAD(&s
->unknown_header_ext
, uext
, next
);
429 ret
= bdrv_pread(bs
->file
, offset
, uext
->data
, uext
->len
);
431 error_setg_errno(errp
, -ret
, "ERROR: unknown extension: "
432 "Could not read data");
439 offset
+= ((ext
.len
+ 7) & ~7);
445 static void cleanup_unknown_header_ext(BlockDriverState
*bs
)
447 BDRVQcow2State
*s
= bs
->opaque
;
448 Qcow2UnknownHeaderExtension
*uext
, *next
;
450 QLIST_FOREACH_SAFE(uext
, &s
->unknown_header_ext
, next
, next
) {
451 QLIST_REMOVE(uext
, next
);
456 static void report_unsupported_feature(Error
**errp
, Qcow2Feature
*table
,
459 g_autoptr(GString
) features
= g_string_sized_new(60);
461 while (table
&& table
->name
[0] != '\0') {
462 if (table
->type
== QCOW2_FEAT_TYPE_INCOMPATIBLE
) {
463 if (mask
& (1ULL << table
->bit
)) {
464 if (features
->len
> 0) {
465 g_string_append(features
, ", ");
467 g_string_append_printf(features
, "%.46s", table
->name
);
468 mask
&= ~(1ULL << table
->bit
);
475 if (features
->len
> 0) {
476 g_string_append(features
, ", ");
478 g_string_append_printf(features
,
479 "Unknown incompatible feature: %" PRIx64
, mask
);
482 error_setg(errp
, "Unsupported qcow2 feature(s): %s", features
->str
);
486 * Sets the dirty bit and flushes afterwards if necessary.
488 * The incompatible_features bit is only set if the image file header was
489 * updated successfully. Therefore it is not required to check the return
490 * value of this function.
492 int qcow2_mark_dirty(BlockDriverState
*bs
)
494 BDRVQcow2State
*s
= bs
->opaque
;
498 assert(s
->qcow_version
>= 3);
500 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
501 return 0; /* already dirty */
504 val
= cpu_to_be64(s
->incompatible_features
| QCOW2_INCOMPAT_DIRTY
);
505 ret
= bdrv_pwrite(bs
->file
, offsetof(QCowHeader
, incompatible_features
),
510 ret
= bdrv_flush(bs
->file
->bs
);
515 /* Only treat image as dirty if the header was updated successfully */
516 s
->incompatible_features
|= QCOW2_INCOMPAT_DIRTY
;
521 * Clears the dirty bit and flushes before if necessary. Only call this
522 * function when there are no pending requests, it does not guard against
523 * concurrent requests dirtying the image.
525 static int qcow2_mark_clean(BlockDriverState
*bs
)
527 BDRVQcow2State
*s
= bs
->opaque
;
529 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
532 s
->incompatible_features
&= ~QCOW2_INCOMPAT_DIRTY
;
534 ret
= qcow2_flush_caches(bs
);
539 return qcow2_update_header(bs
);
545 * Marks the image as corrupt.
547 int qcow2_mark_corrupt(BlockDriverState
*bs
)
549 BDRVQcow2State
*s
= bs
->opaque
;
551 s
->incompatible_features
|= QCOW2_INCOMPAT_CORRUPT
;
552 return qcow2_update_header(bs
);
556 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
557 * before if necessary.
559 int qcow2_mark_consistent(BlockDriverState
*bs
)
561 BDRVQcow2State
*s
= bs
->opaque
;
563 if (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
) {
564 int ret
= qcow2_flush_caches(bs
);
569 s
->incompatible_features
&= ~QCOW2_INCOMPAT_CORRUPT
;
570 return qcow2_update_header(bs
);
575 static void qcow2_add_check_result(BdrvCheckResult
*out
,
576 const BdrvCheckResult
*src
,
577 bool set_allocation_info
)
579 out
->corruptions
+= src
->corruptions
;
580 out
->leaks
+= src
->leaks
;
581 out
->check_errors
+= src
->check_errors
;
582 out
->corruptions_fixed
+= src
->corruptions_fixed
;
583 out
->leaks_fixed
+= src
->leaks_fixed
;
585 if (set_allocation_info
) {
586 out
->image_end_offset
= src
->image_end_offset
;
591 static int coroutine_fn
qcow2_co_check_locked(BlockDriverState
*bs
,
592 BdrvCheckResult
*result
,
595 BdrvCheckResult snapshot_res
= {};
596 BdrvCheckResult refcount_res
= {};
599 memset(result
, 0, sizeof(*result
));
601 ret
= qcow2_check_read_snapshot_table(bs
, &snapshot_res
, fix
);
603 qcow2_add_check_result(result
, &snapshot_res
, false);
607 ret
= qcow2_check_refcounts(bs
, &refcount_res
, fix
);
608 qcow2_add_check_result(result
, &refcount_res
, true);
610 qcow2_add_check_result(result
, &snapshot_res
, false);
614 ret
= qcow2_check_fix_snapshot_table(bs
, &snapshot_res
, fix
);
615 qcow2_add_check_result(result
, &snapshot_res
, false);
620 if (fix
&& result
->check_errors
== 0 && result
->corruptions
== 0) {
621 ret
= qcow2_mark_clean(bs
);
625 return qcow2_mark_consistent(bs
);
630 static int coroutine_fn
qcow2_co_check(BlockDriverState
*bs
,
631 BdrvCheckResult
*result
,
634 BDRVQcow2State
*s
= bs
->opaque
;
637 qemu_co_mutex_lock(&s
->lock
);
638 ret
= qcow2_co_check_locked(bs
, result
, fix
);
639 qemu_co_mutex_unlock(&s
->lock
);
643 int qcow2_validate_table(BlockDriverState
*bs
, uint64_t offset
,
644 uint64_t entries
, size_t entry_len
,
645 int64_t max_size_bytes
, const char *table_name
,
648 BDRVQcow2State
*s
= bs
->opaque
;
650 if (entries
> max_size_bytes
/ entry_len
) {
651 error_setg(errp
, "%s too large", table_name
);
655 /* Use signed INT64_MAX as the maximum even for uint64_t header fields,
656 * because values will be passed to qemu functions taking int64_t. */
657 if ((INT64_MAX
- entries
* entry_len
< offset
) ||
658 (offset_into_cluster(s
, offset
) != 0)) {
659 error_setg(errp
, "%s offset invalid", table_name
);
666 static const char *const mutable_opts
[] = {
667 QCOW2_OPT_LAZY_REFCOUNTS
,
668 QCOW2_OPT_DISCARD_REQUEST
,
669 QCOW2_OPT_DISCARD_SNAPSHOT
,
670 QCOW2_OPT_DISCARD_OTHER
,
672 QCOW2_OPT_OVERLAP_TEMPLATE
,
673 QCOW2_OPT_OVERLAP_MAIN_HEADER
,
674 QCOW2_OPT_OVERLAP_ACTIVE_L1
,
675 QCOW2_OPT_OVERLAP_ACTIVE_L2
,
676 QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
,
677 QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
,
678 QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
,
679 QCOW2_OPT_OVERLAP_INACTIVE_L1
,
680 QCOW2_OPT_OVERLAP_INACTIVE_L2
,
681 QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY
,
682 QCOW2_OPT_CACHE_SIZE
,
683 QCOW2_OPT_L2_CACHE_SIZE
,
684 QCOW2_OPT_L2_CACHE_ENTRY_SIZE
,
685 QCOW2_OPT_REFCOUNT_CACHE_SIZE
,
686 QCOW2_OPT_CACHE_CLEAN_INTERVAL
,
690 static QemuOptsList qcow2_runtime_opts
= {
692 .head
= QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts
.head
),
695 .name
= QCOW2_OPT_LAZY_REFCOUNTS
,
696 .type
= QEMU_OPT_BOOL
,
697 .help
= "Postpone refcount updates",
700 .name
= QCOW2_OPT_DISCARD_REQUEST
,
701 .type
= QEMU_OPT_BOOL
,
702 .help
= "Pass guest discard requests to the layer below",
705 .name
= QCOW2_OPT_DISCARD_SNAPSHOT
,
706 .type
= QEMU_OPT_BOOL
,
707 .help
= "Generate discard requests when snapshot related space "
711 .name
= QCOW2_OPT_DISCARD_OTHER
,
712 .type
= QEMU_OPT_BOOL
,
713 .help
= "Generate discard requests when other clusters are freed",
716 .name
= QCOW2_OPT_OVERLAP
,
717 .type
= QEMU_OPT_STRING
,
718 .help
= "Selects which overlap checks to perform from a range of "
719 "templates (none, constant, cached, all)",
722 .name
= QCOW2_OPT_OVERLAP_TEMPLATE
,
723 .type
= QEMU_OPT_STRING
,
724 .help
= "Selects which overlap checks to perform from a range of "
725 "templates (none, constant, cached, all)",
728 .name
= QCOW2_OPT_OVERLAP_MAIN_HEADER
,
729 .type
= QEMU_OPT_BOOL
,
730 .help
= "Check for unintended writes into the main qcow2 header",
733 .name
= QCOW2_OPT_OVERLAP_ACTIVE_L1
,
734 .type
= QEMU_OPT_BOOL
,
735 .help
= "Check for unintended writes into the active L1 table",
738 .name
= QCOW2_OPT_OVERLAP_ACTIVE_L2
,
739 .type
= QEMU_OPT_BOOL
,
740 .help
= "Check for unintended writes into an active L2 table",
743 .name
= QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
,
744 .type
= QEMU_OPT_BOOL
,
745 .help
= "Check for unintended writes into the refcount table",
748 .name
= QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
,
749 .type
= QEMU_OPT_BOOL
,
750 .help
= "Check for unintended writes into a refcount block",
753 .name
= QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
,
754 .type
= QEMU_OPT_BOOL
,
755 .help
= "Check for unintended writes into the snapshot table",
758 .name
= QCOW2_OPT_OVERLAP_INACTIVE_L1
,
759 .type
= QEMU_OPT_BOOL
,
760 .help
= "Check for unintended writes into an inactive L1 table",
763 .name
= QCOW2_OPT_OVERLAP_INACTIVE_L2
,
764 .type
= QEMU_OPT_BOOL
,
765 .help
= "Check for unintended writes into an inactive L2 table",
768 .name
= QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY
,
769 .type
= QEMU_OPT_BOOL
,
770 .help
= "Check for unintended writes into the bitmap directory",
773 .name
= QCOW2_OPT_CACHE_SIZE
,
774 .type
= QEMU_OPT_SIZE
,
775 .help
= "Maximum combined metadata (L2 tables and refcount blocks) "
779 .name
= QCOW2_OPT_L2_CACHE_SIZE
,
780 .type
= QEMU_OPT_SIZE
,
781 .help
= "Maximum L2 table cache size",
784 .name
= QCOW2_OPT_L2_CACHE_ENTRY_SIZE
,
785 .type
= QEMU_OPT_SIZE
,
786 .help
= "Size of each entry in the L2 cache",
789 .name
= QCOW2_OPT_REFCOUNT_CACHE_SIZE
,
790 .type
= QEMU_OPT_SIZE
,
791 .help
= "Maximum refcount block cache size",
794 .name
= QCOW2_OPT_CACHE_CLEAN_INTERVAL
,
795 .type
= QEMU_OPT_NUMBER
,
796 .help
= "Clean unused cache entries after this time (in seconds)",
798 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.",
799 "ID of secret providing qcow2 AES key or LUKS passphrase"),
800 { /* end of list */ }
804 static const char *overlap_bool_option_names
[QCOW2_OL_MAX_BITNR
] = {
805 [QCOW2_OL_MAIN_HEADER_BITNR
] = QCOW2_OPT_OVERLAP_MAIN_HEADER
,
806 [QCOW2_OL_ACTIVE_L1_BITNR
] = QCOW2_OPT_OVERLAP_ACTIVE_L1
,
807 [QCOW2_OL_ACTIVE_L2_BITNR
] = QCOW2_OPT_OVERLAP_ACTIVE_L2
,
808 [QCOW2_OL_REFCOUNT_TABLE_BITNR
] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
,
809 [QCOW2_OL_REFCOUNT_BLOCK_BITNR
] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
,
810 [QCOW2_OL_SNAPSHOT_TABLE_BITNR
] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
,
811 [QCOW2_OL_INACTIVE_L1_BITNR
] = QCOW2_OPT_OVERLAP_INACTIVE_L1
,
812 [QCOW2_OL_INACTIVE_L2_BITNR
] = QCOW2_OPT_OVERLAP_INACTIVE_L2
,
813 [QCOW2_OL_BITMAP_DIRECTORY_BITNR
] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY
,
816 static void cache_clean_timer_cb(void *opaque
)
818 BlockDriverState
*bs
= opaque
;
819 BDRVQcow2State
*s
= bs
->opaque
;
820 qcow2_cache_clean_unused(s
->l2_table_cache
);
821 qcow2_cache_clean_unused(s
->refcount_block_cache
);
822 timer_mod(s
->cache_clean_timer
, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL
) +
823 (int64_t) s
->cache_clean_interval
* 1000);
826 static void cache_clean_timer_init(BlockDriverState
*bs
, AioContext
*context
)
828 BDRVQcow2State
*s
= bs
->opaque
;
829 if (s
->cache_clean_interval
> 0) {
830 s
->cache_clean_timer
= aio_timer_new(context
, QEMU_CLOCK_VIRTUAL
,
831 SCALE_MS
, cache_clean_timer_cb
,
833 timer_mod(s
->cache_clean_timer
, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL
) +
834 (int64_t) s
->cache_clean_interval
* 1000);
838 static void cache_clean_timer_del(BlockDriverState
*bs
)
840 BDRVQcow2State
*s
= bs
->opaque
;
841 if (s
->cache_clean_timer
) {
842 timer_del(s
->cache_clean_timer
);
843 timer_free(s
->cache_clean_timer
);
844 s
->cache_clean_timer
= NULL
;
848 static void qcow2_detach_aio_context(BlockDriverState
*bs
)
850 cache_clean_timer_del(bs
);
853 static void qcow2_attach_aio_context(BlockDriverState
*bs
,
854 AioContext
*new_context
)
856 cache_clean_timer_init(bs
, new_context
);
859 static void read_cache_sizes(BlockDriverState
*bs
, QemuOpts
*opts
,
860 uint64_t *l2_cache_size
,
861 uint64_t *l2_cache_entry_size
,
862 uint64_t *refcount_cache_size
, Error
**errp
)
864 BDRVQcow2State
*s
= bs
->opaque
;
865 uint64_t combined_cache_size
, l2_cache_max_setting
;
866 bool l2_cache_size_set
, refcount_cache_size_set
, combined_cache_size_set
;
867 bool l2_cache_entry_size_set
;
868 int min_refcount_cache
= MIN_REFCOUNT_CACHE_SIZE
* s
->cluster_size
;
869 uint64_t virtual_disk_size
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
870 uint64_t max_l2_entries
= DIV_ROUND_UP(virtual_disk_size
, s
->cluster_size
);
871 /* An L2 table is always one cluster in size so the max cache size
872 * should be a multiple of the cluster size. */
873 uint64_t max_l2_cache
= ROUND_UP(max_l2_entries
* sizeof(uint64_t),
876 combined_cache_size_set
= qemu_opt_get(opts
, QCOW2_OPT_CACHE_SIZE
);
877 l2_cache_size_set
= qemu_opt_get(opts
, QCOW2_OPT_L2_CACHE_SIZE
);
878 refcount_cache_size_set
= qemu_opt_get(opts
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
);
879 l2_cache_entry_size_set
= qemu_opt_get(opts
, QCOW2_OPT_L2_CACHE_ENTRY_SIZE
);
881 combined_cache_size
= qemu_opt_get_size(opts
, QCOW2_OPT_CACHE_SIZE
, 0);
882 l2_cache_max_setting
= qemu_opt_get_size(opts
, QCOW2_OPT_L2_CACHE_SIZE
,
883 DEFAULT_L2_CACHE_MAX_SIZE
);
884 *refcount_cache_size
= qemu_opt_get_size(opts
,
885 QCOW2_OPT_REFCOUNT_CACHE_SIZE
, 0);
887 *l2_cache_entry_size
= qemu_opt_get_size(
888 opts
, QCOW2_OPT_L2_CACHE_ENTRY_SIZE
, s
->cluster_size
);
890 *l2_cache_size
= MIN(max_l2_cache
, l2_cache_max_setting
);
892 if (combined_cache_size_set
) {
893 if (l2_cache_size_set
&& refcount_cache_size_set
) {
894 error_setg(errp
, QCOW2_OPT_CACHE_SIZE
", " QCOW2_OPT_L2_CACHE_SIZE
895 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE
" may not be set "
898 } else if (l2_cache_size_set
&&
899 (l2_cache_max_setting
> combined_cache_size
)) {
900 error_setg(errp
, QCOW2_OPT_L2_CACHE_SIZE
" may not exceed "
901 QCOW2_OPT_CACHE_SIZE
);
903 } else if (*refcount_cache_size
> combined_cache_size
) {
904 error_setg(errp
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
" may not exceed "
905 QCOW2_OPT_CACHE_SIZE
);
909 if (l2_cache_size_set
) {
910 *refcount_cache_size
= combined_cache_size
- *l2_cache_size
;
911 } else if (refcount_cache_size_set
) {
912 *l2_cache_size
= combined_cache_size
- *refcount_cache_size
;
914 /* Assign as much memory as possible to the L2 cache, and
915 * use the remainder for the refcount cache */
916 if (combined_cache_size
>= max_l2_cache
+ min_refcount_cache
) {
917 *l2_cache_size
= max_l2_cache
;
918 *refcount_cache_size
= combined_cache_size
- *l2_cache_size
;
920 *refcount_cache_size
=
921 MIN(combined_cache_size
, min_refcount_cache
);
922 *l2_cache_size
= combined_cache_size
- *refcount_cache_size
;
928 * If the L2 cache is not enough to cover the whole disk then
929 * default to 4KB entries. Smaller entries reduce the cost of
930 * loads and evictions and increase I/O performance.
932 if (*l2_cache_size
< max_l2_cache
&& !l2_cache_entry_size_set
) {
933 *l2_cache_entry_size
= MIN(s
->cluster_size
, 4096);
936 /* l2_cache_size and refcount_cache_size are ensured to have at least
937 * their minimum values in qcow2_update_options_prepare() */
939 if (*l2_cache_entry_size
< (1 << MIN_CLUSTER_BITS
) ||
940 *l2_cache_entry_size
> s
->cluster_size
||
941 !is_power_of_2(*l2_cache_entry_size
)) {
942 error_setg(errp
, "L2 cache entry size must be a power of two "
943 "between %d and the cluster size (%d)",
944 1 << MIN_CLUSTER_BITS
, s
->cluster_size
);
949 typedef struct Qcow2ReopenState
{
950 Qcow2Cache
*l2_table_cache
;
951 Qcow2Cache
*refcount_block_cache
;
952 int l2_slice_size
; /* Number of entries in a slice of the L2 table */
953 bool use_lazy_refcounts
;
955 bool discard_passthrough
[QCOW2_DISCARD_MAX
];
956 uint64_t cache_clean_interval
;
957 QCryptoBlockOpenOptions
*crypto_opts
; /* Disk encryption runtime options */
960 static int qcow2_update_options_prepare(BlockDriverState
*bs
,
962 QDict
*options
, int flags
,
965 BDRVQcow2State
*s
= bs
->opaque
;
966 QemuOpts
*opts
= NULL
;
967 const char *opt_overlap_check
, *opt_overlap_check_template
;
968 int overlap_check_template
= 0;
969 uint64_t l2_cache_size
, l2_cache_entry_size
, refcount_cache_size
;
971 const char *encryptfmt
;
972 QDict
*encryptopts
= NULL
;
973 Error
*local_err
= NULL
;
976 qdict_extract_subqdict(options
, &encryptopts
, "encrypt.");
977 encryptfmt
= qdict_get_try_str(encryptopts
, "format");
979 opts
= qemu_opts_create(&qcow2_runtime_opts
, NULL
, 0, &error_abort
);
980 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
982 error_propagate(errp
, local_err
);
987 /* get L2 table/refcount block cache size from command line options */
988 read_cache_sizes(bs
, opts
, &l2_cache_size
, &l2_cache_entry_size
,
989 &refcount_cache_size
, &local_err
);
991 error_propagate(errp
, local_err
);
996 l2_cache_size
/= l2_cache_entry_size
;
997 if (l2_cache_size
< MIN_L2_CACHE_SIZE
) {
998 l2_cache_size
= MIN_L2_CACHE_SIZE
;
1000 if (l2_cache_size
> INT_MAX
) {
1001 error_setg(errp
, "L2 cache size too big");
1006 refcount_cache_size
/= s
->cluster_size
;
1007 if (refcount_cache_size
< MIN_REFCOUNT_CACHE_SIZE
) {
1008 refcount_cache_size
= MIN_REFCOUNT_CACHE_SIZE
;
1010 if (refcount_cache_size
> INT_MAX
) {
1011 error_setg(errp
, "Refcount cache size too big");
1016 /* alloc new L2 table/refcount block cache, flush old one */
1017 if (s
->l2_table_cache
) {
1018 ret
= qcow2_cache_flush(bs
, s
->l2_table_cache
);
1020 error_setg_errno(errp
, -ret
, "Failed to flush the L2 table cache");
1025 if (s
->refcount_block_cache
) {
1026 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
1028 error_setg_errno(errp
, -ret
,
1029 "Failed to flush the refcount block cache");
1034 r
->l2_slice_size
= l2_cache_entry_size
/ sizeof(uint64_t);
1035 r
->l2_table_cache
= qcow2_cache_create(bs
, l2_cache_size
,
1036 l2_cache_entry_size
);
1037 r
->refcount_block_cache
= qcow2_cache_create(bs
, refcount_cache_size
,
1039 if (r
->l2_table_cache
== NULL
|| r
->refcount_block_cache
== NULL
) {
1040 error_setg(errp
, "Could not allocate metadata caches");
1045 /* New interval for cache cleanup timer */
1046 r
->cache_clean_interval
=
1047 qemu_opt_get_number(opts
, QCOW2_OPT_CACHE_CLEAN_INTERVAL
,
1048 DEFAULT_CACHE_CLEAN_INTERVAL
);
1049 #ifndef CONFIG_LINUX
1050 if (r
->cache_clean_interval
!= 0) {
1051 error_setg(errp
, QCOW2_OPT_CACHE_CLEAN_INTERVAL
1052 " not supported on this host");
1057 if (r
->cache_clean_interval
> UINT_MAX
) {
1058 error_setg(errp
, "Cache clean interval too big");
1063 /* lazy-refcounts; flush if going from enabled to disabled */
1064 r
->use_lazy_refcounts
= qemu_opt_get_bool(opts
, QCOW2_OPT_LAZY_REFCOUNTS
,
1065 (s
->compatible_features
& QCOW2_COMPAT_LAZY_REFCOUNTS
));
1066 if (r
->use_lazy_refcounts
&& s
->qcow_version
< 3) {
1067 error_setg(errp
, "Lazy refcounts require a qcow2 image with at least "
1068 "qemu 1.1 compatibility level");
1073 if (s
->use_lazy_refcounts
&& !r
->use_lazy_refcounts
) {
1074 ret
= qcow2_mark_clean(bs
);
1076 error_setg_errno(errp
, -ret
, "Failed to disable lazy refcounts");
1081 /* Overlap check options */
1082 opt_overlap_check
= qemu_opt_get(opts
, QCOW2_OPT_OVERLAP
);
1083 opt_overlap_check_template
= qemu_opt_get(opts
, QCOW2_OPT_OVERLAP_TEMPLATE
);
1084 if (opt_overlap_check_template
&& opt_overlap_check
&&
1085 strcmp(opt_overlap_check_template
, opt_overlap_check
))
1087 error_setg(errp
, "Conflicting values for qcow2 options '"
1088 QCOW2_OPT_OVERLAP
"' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
1089 "' ('%s')", opt_overlap_check
, opt_overlap_check_template
);
1093 if (!opt_overlap_check
) {
1094 opt_overlap_check
= opt_overlap_check_template
?: "cached";
1097 if (!strcmp(opt_overlap_check
, "none")) {
1098 overlap_check_template
= 0;
1099 } else if (!strcmp(opt_overlap_check
, "constant")) {
1100 overlap_check_template
= QCOW2_OL_CONSTANT
;
1101 } else if (!strcmp(opt_overlap_check
, "cached")) {
1102 overlap_check_template
= QCOW2_OL_CACHED
;
1103 } else if (!strcmp(opt_overlap_check
, "all")) {
1104 overlap_check_template
= QCOW2_OL_ALL
;
1106 error_setg(errp
, "Unsupported value '%s' for qcow2 option "
1107 "'overlap-check'. Allowed are any of the following: "
1108 "none, constant, cached, all", opt_overlap_check
);
1113 r
->overlap_check
= 0;
1114 for (i
= 0; i
< QCOW2_OL_MAX_BITNR
; i
++) {
1115 /* overlap-check defines a template bitmask, but every flag may be
1116 * overwritten through the associated boolean option */
1118 qemu_opt_get_bool(opts
, overlap_bool_option_names
[i
],
1119 overlap_check_template
& (1 << i
)) << i
;
1122 r
->discard_passthrough
[QCOW2_DISCARD_NEVER
] = false;
1123 r
->discard_passthrough
[QCOW2_DISCARD_ALWAYS
] = true;
1124 r
->discard_passthrough
[QCOW2_DISCARD_REQUEST
] =
1125 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_REQUEST
,
1126 flags
& BDRV_O_UNMAP
);
1127 r
->discard_passthrough
[QCOW2_DISCARD_SNAPSHOT
] =
1128 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_SNAPSHOT
, true);
1129 r
->discard_passthrough
[QCOW2_DISCARD_OTHER
] =
1130 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_OTHER
, false);
1132 switch (s
->crypt_method_header
) {
1133 case QCOW_CRYPT_NONE
:
1135 error_setg(errp
, "No encryption in image header, but options "
1136 "specified format '%s'", encryptfmt
);
1142 case QCOW_CRYPT_AES
:
1143 if (encryptfmt
&& !g_str_equal(encryptfmt
, "aes")) {
1145 "Header reported 'aes' encryption format but "
1146 "options specify '%s'", encryptfmt
);
1150 qdict_put_str(encryptopts
, "format", "qcow");
1151 r
->crypto_opts
= block_crypto_open_opts_init(encryptopts
, errp
);
1154 case QCOW_CRYPT_LUKS
:
1155 if (encryptfmt
&& !g_str_equal(encryptfmt
, "luks")) {
1157 "Header reported 'luks' encryption format but "
1158 "options specify '%s'", encryptfmt
);
1162 qdict_put_str(encryptopts
, "format", "luks");
1163 r
->crypto_opts
= block_crypto_open_opts_init(encryptopts
, errp
);
1167 error_setg(errp
, "Unsupported encryption method %d",
1168 s
->crypt_method_header
);
1171 if (s
->crypt_method_header
!= QCOW_CRYPT_NONE
&& !r
->crypto_opts
) {
1178 qobject_unref(encryptopts
);
1179 qemu_opts_del(opts
);
1184 static void qcow2_update_options_commit(BlockDriverState
*bs
,
1185 Qcow2ReopenState
*r
)
1187 BDRVQcow2State
*s
= bs
->opaque
;
1190 if (s
->l2_table_cache
) {
1191 qcow2_cache_destroy(s
->l2_table_cache
);
1193 if (s
->refcount_block_cache
) {
1194 qcow2_cache_destroy(s
->refcount_block_cache
);
1196 s
->l2_table_cache
= r
->l2_table_cache
;
1197 s
->refcount_block_cache
= r
->refcount_block_cache
;
1198 s
->l2_slice_size
= r
->l2_slice_size
;
1200 s
->overlap_check
= r
->overlap_check
;
1201 s
->use_lazy_refcounts
= r
->use_lazy_refcounts
;
1203 for (i
= 0; i
< QCOW2_DISCARD_MAX
; i
++) {
1204 s
->discard_passthrough
[i
] = r
->discard_passthrough
[i
];
1207 if (s
->cache_clean_interval
!= r
->cache_clean_interval
) {
1208 cache_clean_timer_del(bs
);
1209 s
->cache_clean_interval
= r
->cache_clean_interval
;
1210 cache_clean_timer_init(bs
, bdrv_get_aio_context(bs
));
1213 qapi_free_QCryptoBlockOpenOptions(s
->crypto_opts
);
1214 s
->crypto_opts
= r
->crypto_opts
;
1217 static void qcow2_update_options_abort(BlockDriverState
*bs
,
1218 Qcow2ReopenState
*r
)
1220 if (r
->l2_table_cache
) {
1221 qcow2_cache_destroy(r
->l2_table_cache
);
1223 if (r
->refcount_block_cache
) {
1224 qcow2_cache_destroy(r
->refcount_block_cache
);
1226 qapi_free_QCryptoBlockOpenOptions(r
->crypto_opts
);
1229 static int qcow2_update_options(BlockDriverState
*bs
, QDict
*options
,
1230 int flags
, Error
**errp
)
1232 Qcow2ReopenState r
= {};
1235 ret
= qcow2_update_options_prepare(bs
, &r
, options
, flags
, errp
);
1237 qcow2_update_options_commit(bs
, &r
);
1239 qcow2_update_options_abort(bs
, &r
);
1245 /* Called with s->lock held. */
1246 static int coroutine_fn
qcow2_do_open(BlockDriverState
*bs
, QDict
*options
,
1247 int flags
, Error
**errp
)
1249 BDRVQcow2State
*s
= bs
->opaque
;
1250 unsigned int len
, i
;
1253 Error
*local_err
= NULL
;
1255 uint64_t l1_vm_state_index
;
1256 bool update_header
= false;
1258 ret
= bdrv_pread(bs
->file
, 0, &header
, sizeof(header
));
1260 error_setg_errno(errp
, -ret
, "Could not read qcow2 header");
1263 header
.magic
= be32_to_cpu(header
.magic
);
1264 header
.version
= be32_to_cpu(header
.version
);
1265 header
.backing_file_offset
= be64_to_cpu(header
.backing_file_offset
);
1266 header
.backing_file_size
= be32_to_cpu(header
.backing_file_size
);
1267 header
.size
= be64_to_cpu(header
.size
);
1268 header
.cluster_bits
= be32_to_cpu(header
.cluster_bits
);
1269 header
.crypt_method
= be32_to_cpu(header
.crypt_method
);
1270 header
.l1_table_offset
= be64_to_cpu(header
.l1_table_offset
);
1271 header
.l1_size
= be32_to_cpu(header
.l1_size
);
1272 header
.refcount_table_offset
= be64_to_cpu(header
.refcount_table_offset
);
1273 header
.refcount_table_clusters
=
1274 be32_to_cpu(header
.refcount_table_clusters
);
1275 header
.snapshots_offset
= be64_to_cpu(header
.snapshots_offset
);
1276 header
.nb_snapshots
= be32_to_cpu(header
.nb_snapshots
);
1278 if (header
.magic
!= QCOW_MAGIC
) {
1279 error_setg(errp
, "Image is not in qcow2 format");
1283 if (header
.version
< 2 || header
.version
> 3) {
1284 error_setg(errp
, "Unsupported qcow2 version %" PRIu32
, header
.version
);
1289 s
->qcow_version
= header
.version
;
1291 /* Initialise cluster size */
1292 if (header
.cluster_bits
< MIN_CLUSTER_BITS
||
1293 header
.cluster_bits
> MAX_CLUSTER_BITS
) {
1294 error_setg(errp
, "Unsupported cluster size: 2^%" PRIu32
,
1295 header
.cluster_bits
);
1300 s
->cluster_bits
= header
.cluster_bits
;
1301 s
->cluster_size
= 1 << s
->cluster_bits
;
1303 /* Initialise version 3 header fields */
1304 if (header
.version
== 2) {
1305 header
.incompatible_features
= 0;
1306 header
.compatible_features
= 0;
1307 header
.autoclear_features
= 0;
1308 header
.refcount_order
= 4;
1309 header
.header_length
= 72;
1311 header
.incompatible_features
=
1312 be64_to_cpu(header
.incompatible_features
);
1313 header
.compatible_features
= be64_to_cpu(header
.compatible_features
);
1314 header
.autoclear_features
= be64_to_cpu(header
.autoclear_features
);
1315 header
.refcount_order
= be32_to_cpu(header
.refcount_order
);
1316 header
.header_length
= be32_to_cpu(header
.header_length
);
1318 if (header
.header_length
< 104) {
1319 error_setg(errp
, "qcow2 header too short");
1325 if (header
.header_length
> s
->cluster_size
) {
1326 error_setg(errp
, "qcow2 header exceeds cluster size");
1331 if (header
.header_length
> sizeof(header
)) {
1332 s
->unknown_header_fields_size
= header
.header_length
- sizeof(header
);
1333 s
->unknown_header_fields
= g_malloc(s
->unknown_header_fields_size
);
1334 ret
= bdrv_pread(bs
->file
, sizeof(header
), s
->unknown_header_fields
,
1335 s
->unknown_header_fields_size
);
1337 error_setg_errno(errp
, -ret
, "Could not read unknown qcow2 header "
1343 if (header
.backing_file_offset
> s
->cluster_size
) {
1344 error_setg(errp
, "Invalid backing file offset");
1349 if (header
.backing_file_offset
) {
1350 ext_end
= header
.backing_file_offset
;
1352 ext_end
= 1 << header
.cluster_bits
;
1355 /* Handle feature bits */
1356 s
->incompatible_features
= header
.incompatible_features
;
1357 s
->compatible_features
= header
.compatible_features
;
1358 s
->autoclear_features
= header
.autoclear_features
;
1360 if (s
->incompatible_features
& ~QCOW2_INCOMPAT_MASK
) {
1361 void *feature_table
= NULL
;
1362 qcow2_read_extensions(bs
, header
.header_length
, ext_end
,
1363 &feature_table
, flags
, NULL
, NULL
);
1364 report_unsupported_feature(errp
, feature_table
,
1365 s
->incompatible_features
&
1366 ~QCOW2_INCOMPAT_MASK
);
1368 g_free(feature_table
);
1372 if (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
) {
1373 /* Corrupt images may not be written to unless they are being repaired
1375 if ((flags
& BDRV_O_RDWR
) && !(flags
& BDRV_O_CHECK
)) {
1376 error_setg(errp
, "qcow2: Image is corrupt; cannot be opened "
1383 /* Check support for various header values */
1384 if (header
.refcount_order
> 6) {
1385 error_setg(errp
, "Reference count entry width too large; may not "
1390 s
->refcount_order
= header
.refcount_order
;
1391 s
->refcount_bits
= 1 << s
->refcount_order
;
1392 s
->refcount_max
= UINT64_C(1) << (s
->refcount_bits
- 1);
1393 s
->refcount_max
+= s
->refcount_max
- 1;
1395 s
->crypt_method_header
= header
.crypt_method
;
1396 if (s
->crypt_method_header
) {
1397 if (bdrv_uses_whitelist() &&
1398 s
->crypt_method_header
== QCOW_CRYPT_AES
) {
1400 "Use of AES-CBC encrypted qcow2 images is no longer "
1401 "supported in system emulators");
1402 error_append_hint(errp
,
1403 "You can use 'qemu-img convert' to convert your "
1404 "image to an alternative supported format, such "
1405 "as unencrypted qcow2, or raw with the LUKS "
1406 "format instead.\n");
1411 if (s
->crypt_method_header
== QCOW_CRYPT_AES
) {
1412 s
->crypt_physical_offset
= false;
1414 /* Assuming LUKS and any future crypt methods we
1415 * add will all use physical offsets, due to the
1416 * fact that the alternative is insecure... */
1417 s
->crypt_physical_offset
= true;
1420 bs
->encrypted
= true;
1423 s
->l2_bits
= s
->cluster_bits
- 3; /* L2 is always one cluster */
1424 s
->l2_size
= 1 << s
->l2_bits
;
1425 /* 2^(s->refcount_order - 3) is the refcount width in bytes */
1426 s
->refcount_block_bits
= s
->cluster_bits
- (s
->refcount_order
- 3);
1427 s
->refcount_block_size
= 1 << s
->refcount_block_bits
;
1428 bs
->total_sectors
= header
.size
/ BDRV_SECTOR_SIZE
;
1429 s
->csize_shift
= (62 - (s
->cluster_bits
- 8));
1430 s
->csize_mask
= (1 << (s
->cluster_bits
- 8)) - 1;
1431 s
->cluster_offset_mask
= (1LL << s
->csize_shift
) - 1;
1433 s
->refcount_table_offset
= header
.refcount_table_offset
;
1434 s
->refcount_table_size
=
1435 header
.refcount_table_clusters
<< (s
->cluster_bits
- 3);
1437 if (header
.refcount_table_clusters
== 0 && !(flags
& BDRV_O_CHECK
)) {
1438 error_setg(errp
, "Image does not contain a reference count table");
1443 ret
= qcow2_validate_table(bs
, s
->refcount_table_offset
,
1444 header
.refcount_table_clusters
,
1445 s
->cluster_size
, QCOW_MAX_REFTABLE_SIZE
,
1446 "Reference count table", errp
);
1451 if (!(flags
& BDRV_O_CHECK
)) {
1453 * The total size in bytes of the snapshot table is checked in
1454 * qcow2_read_snapshots() because the size of each snapshot is
1455 * variable and we don't know it yet.
1456 * Here we only check the offset and number of snapshots.
1458 ret
= qcow2_validate_table(bs
, header
.snapshots_offset
,
1459 header
.nb_snapshots
,
1460 sizeof(QCowSnapshotHeader
),
1461 sizeof(QCowSnapshotHeader
) *
1463 "Snapshot table", errp
);
1469 /* read the level 1 table */
1470 ret
= qcow2_validate_table(bs
, header
.l1_table_offset
,
1471 header
.l1_size
, sizeof(uint64_t),
1472 QCOW_MAX_L1_SIZE
, "Active L1 table", errp
);
1476 s
->l1_size
= header
.l1_size
;
1477 s
->l1_table_offset
= header
.l1_table_offset
;
1479 l1_vm_state_index
= size_to_l1(s
, header
.size
);
1480 if (l1_vm_state_index
> INT_MAX
) {
1481 error_setg(errp
, "Image is too big");
1485 s
->l1_vm_state_index
= l1_vm_state_index
;
1487 /* the L1 table must contain at least enough entries to put
1488 header.size bytes */
1489 if (s
->l1_size
< s
->l1_vm_state_index
) {
1490 error_setg(errp
, "L1 table is too small");
1495 if (s
->l1_size
> 0) {
1496 s
->l1_table
= qemu_try_blockalign(bs
->file
->bs
,
1497 s
->l1_size
* sizeof(uint64_t));
1498 if (s
->l1_table
== NULL
) {
1499 error_setg(errp
, "Could not allocate L1 table");
1503 ret
= bdrv_pread(bs
->file
, s
->l1_table_offset
, s
->l1_table
,
1504 s
->l1_size
* sizeof(uint64_t));
1506 error_setg_errno(errp
, -ret
, "Could not read L1 table");
1509 for(i
= 0;i
< s
->l1_size
; i
++) {
1510 s
->l1_table
[i
] = be64_to_cpu(s
->l1_table
[i
]);
1514 /* Parse driver-specific options */
1515 ret
= qcow2_update_options(bs
, options
, flags
, errp
);
1522 ret
= qcow2_refcount_init(bs
);
1524 error_setg_errno(errp
, -ret
, "Could not initialize refcount handling");
1528 QLIST_INIT(&s
->cluster_allocs
);
1529 QTAILQ_INIT(&s
->discards
);
1531 /* read qcow2 extensions */
1532 if (qcow2_read_extensions(bs
, header
.header_length
, ext_end
, NULL
,
1533 flags
, &update_header
, &local_err
)) {
1534 error_propagate(errp
, local_err
);
1539 /* Open external data file */
1540 s
->data_file
= bdrv_open_child(NULL
, options
, "data-file", bs
, &child_file
,
1543 error_propagate(errp
, local_err
);
1548 if (s
->incompatible_features
& QCOW2_INCOMPAT_DATA_FILE
) {
1549 if (!s
->data_file
&& s
->image_data_file
) {
1550 s
->data_file
= bdrv_open_child(s
->image_data_file
, options
,
1551 "data-file", bs
, &child_file
,
1553 if (!s
->data_file
) {
1558 if (!s
->data_file
) {
1559 error_setg(errp
, "'data-file' is required for this image");
1565 error_setg(errp
, "'data-file' can only be set for images with an "
1566 "external data file");
1571 s
->data_file
= bs
->file
;
1573 if (data_file_is_raw(bs
)) {
1574 error_setg(errp
, "data-file-raw requires a data file");
1580 /* qcow2_read_extension may have set up the crypto context
1581 * if the crypt method needs a header region, some methods
1582 * don't need header extensions, so must check here
1584 if (s
->crypt_method_header
&& !s
->crypto
) {
1585 if (s
->crypt_method_header
== QCOW_CRYPT_AES
) {
1586 unsigned int cflags
= 0;
1587 if (flags
& BDRV_O_NO_IO
) {
1588 cflags
|= QCRYPTO_BLOCK_OPEN_NO_IO
;
1590 s
->crypto
= qcrypto_block_open(s
->crypto_opts
, "encrypt.",
1592 QCOW2_MAX_THREADS
, errp
);
1597 } else if (!(flags
& BDRV_O_NO_IO
)) {
1598 error_setg(errp
, "Missing CRYPTO header for crypt method %d",
1599 s
->crypt_method_header
);
1605 /* read the backing file name */
1606 if (header
.backing_file_offset
!= 0) {
1607 len
= header
.backing_file_size
;
1608 if (len
> MIN(1023, s
->cluster_size
- header
.backing_file_offset
) ||
1609 len
>= sizeof(bs
->backing_file
)) {
1610 error_setg(errp
, "Backing file name too long");
1614 ret
= bdrv_pread(bs
->file
, header
.backing_file_offset
,
1615 bs
->auto_backing_file
, len
);
1617 error_setg_errno(errp
, -ret
, "Could not read backing file name");
1620 bs
->auto_backing_file
[len
] = '\0';
1621 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
),
1622 bs
->auto_backing_file
);
1623 s
->image_backing_file
= g_strdup(bs
->auto_backing_file
);
1627 * Internal snapshots; skip reading them in check mode, because
1628 * we do not need them then, and we do not want to abort because
1629 * of a broken table.
1631 if (!(flags
& BDRV_O_CHECK
)) {
1632 s
->snapshots_offset
= header
.snapshots_offset
;
1633 s
->nb_snapshots
= header
.nb_snapshots
;
1635 ret
= qcow2_read_snapshots(bs
, errp
);
1641 /* Clear unknown autoclear feature bits */
1642 update_header
|= s
->autoclear_features
& ~QCOW2_AUTOCLEAR_MASK
;
1644 update_header
&& !bs
->read_only
&& !(flags
& BDRV_O_INACTIVE
);
1645 if (update_header
) {
1646 s
->autoclear_features
&= QCOW2_AUTOCLEAR_MASK
;
1649 /* == Handle persistent dirty bitmaps ==
1651 * We want load dirty bitmaps in three cases:
1653 * 1. Normal open of the disk in active mode, not related to invalidation
1656 * 2. Invalidation of the target vm after pre-copy phase of migration, if
1657 * bitmaps are _not_ migrating through migration channel, i.e.
1658 * 'dirty-bitmaps' capability is disabled.
1660 * 3. Invalidation of source vm after failed or canceled migration.
1661 * This is a very interesting case. There are two possible types of
1664 * A. Stored on inactivation and removed. They should be loaded from the
1667 * B. Not stored: not-persistent bitmaps and bitmaps, migrated through
1668 * the migration channel (with dirty-bitmaps capability).
1670 * On the other hand, there are two possible sub-cases:
1672 * 3.1 disk was changed by somebody else while were inactive. In this
1673 * case all in-RAM dirty bitmaps (both persistent and not) are
1674 * definitely invalid. And we don't have any method to determine
1677 * Simple and safe thing is to just drop all the bitmaps of type B on
1678 * inactivation. But in this case we lose bitmaps in valid 4.2 case.
1680 * On the other hand, resuming source vm, if disk was already changed
1681 * is a bad thing anyway: not only bitmaps, the whole vm state is
1682 * out of sync with disk.
1684 * This means, that user or management tool, who for some reason
1685 * decided to resume source vm, after disk was already changed by
1686 * target vm, should at least drop all dirty bitmaps by hand.
1688 * So, we can ignore this case for now, but TODO: "generation"
1689 * extension for qcow2, to determine, that image was changed after
1690 * last inactivation. And if it is changed, we will drop (or at least
1691 * mark as 'invalid' all the bitmaps of type B, both persistent
1694 * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved
1695 * to disk ('dirty-bitmaps' capability disabled), or not saved
1696 * ('dirty-bitmaps' capability enabled), but we don't need to care
1697 * of: let's load bitmaps as always: stored bitmaps will be loaded,
1698 * and not stored has flag IN_USE=1 in the image and will be skipped
1701 * One remaining possible case when we don't want load bitmaps:
1703 * 4. Open disk in inactive mode in target vm (bitmaps are migrating or
1704 * will be loaded on invalidation, no needs try loading them before)
1707 if (!(bdrv_get_flags(bs
) & BDRV_O_INACTIVE
)) {
1708 /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */
1709 bool header_updated
= qcow2_load_dirty_bitmaps(bs
, &local_err
);
1710 if (local_err
!= NULL
) {
1711 error_propagate(errp
, local_err
);
1716 update_header
= update_header
&& !header_updated
;
1719 if (update_header
) {
1720 ret
= qcow2_update_header(bs
);
1722 error_setg_errno(errp
, -ret
, "Could not update qcow2 header");
1727 bs
->supported_zero_flags
= header
.version
>= 3 ?
1728 BDRV_REQ_MAY_UNMAP
| BDRV_REQ_NO_FALLBACK
: 0;
1730 /* Repair image if dirty */
1731 if (!(flags
& (BDRV_O_CHECK
| BDRV_O_INACTIVE
)) && !bs
->read_only
&&
1732 (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
)) {
1733 BdrvCheckResult result
= {0};
1735 ret
= qcow2_co_check_locked(bs
, &result
,
1736 BDRV_FIX_ERRORS
| BDRV_FIX_LEAKS
);
1737 if (ret
< 0 || result
.check_errors
) {
1741 error_setg_errno(errp
, -ret
, "Could not repair dirty image");
1748 BdrvCheckResult result
= {0};
1749 qcow2_check_refcounts(bs
, &result
, 0);
1753 qemu_co_queue_init(&s
->thread_task_queue
);
1758 g_free(s
->image_data_file
);
1759 if (has_data_file(bs
)) {
1760 bdrv_unref_child(bs
, s
->data_file
);
1762 g_free(s
->unknown_header_fields
);
1763 cleanup_unknown_header_ext(bs
);
1764 qcow2_free_snapshots(bs
);
1765 qcow2_refcount_close(bs
);
1766 qemu_vfree(s
->l1_table
);
1767 /* else pre-write overlap checks in cache_destroy may crash */
1769 cache_clean_timer_del(bs
);
1770 if (s
->l2_table_cache
) {
1771 qcow2_cache_destroy(s
->l2_table_cache
);
1773 if (s
->refcount_block_cache
) {
1774 qcow2_cache_destroy(s
->refcount_block_cache
);
1776 qcrypto_block_free(s
->crypto
);
1777 qapi_free_QCryptoBlockOpenOptions(s
->crypto_opts
);
1781 typedef struct QCow2OpenCo
{
1782 BlockDriverState
*bs
;
1789 static void coroutine_fn
qcow2_open_entry(void *opaque
)
1791 QCow2OpenCo
*qoc
= opaque
;
1792 BDRVQcow2State
*s
= qoc
->bs
->opaque
;
1794 qemu_co_mutex_lock(&s
->lock
);
1795 qoc
->ret
= qcow2_do_open(qoc
->bs
, qoc
->options
, qoc
->flags
, qoc
->errp
);
1796 qemu_co_mutex_unlock(&s
->lock
);
1799 static int qcow2_open(BlockDriverState
*bs
, QDict
*options
, int flags
,
1802 BDRVQcow2State
*s
= bs
->opaque
;
1811 bs
->file
= bdrv_open_child(NULL
, options
, "file", bs
, &child_file
,
1817 /* Initialise locks */
1818 qemu_co_mutex_init(&s
->lock
);
1820 if (qemu_in_coroutine()) {
1821 /* From bdrv_co_create. */
1822 qcow2_open_entry(&qoc
);
1824 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
1825 qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry
, &qoc
));
1826 BDRV_POLL_WHILE(bs
, qoc
.ret
== -EINPROGRESS
);
1831 static void qcow2_refresh_limits(BlockDriverState
*bs
, Error
**errp
)
1833 BDRVQcow2State
*s
= bs
->opaque
;
1835 if (bs
->encrypted
) {
1836 /* Encryption works on a sector granularity */
1837 bs
->bl
.request_alignment
= qcrypto_block_get_sector_size(s
->crypto
);
1839 bs
->bl
.pwrite_zeroes_alignment
= s
->cluster_size
;
1840 bs
->bl
.pdiscard_alignment
= s
->cluster_size
;
1843 static int qcow2_reopen_prepare(BDRVReopenState
*state
,
1844 BlockReopenQueue
*queue
, Error
**errp
)
1846 Qcow2ReopenState
*r
;
1849 r
= g_new0(Qcow2ReopenState
, 1);
1852 ret
= qcow2_update_options_prepare(state
->bs
, r
, state
->options
,
1853 state
->flags
, errp
);
1858 /* We need to write out any unwritten data if we reopen read-only. */
1859 if ((state
->flags
& BDRV_O_RDWR
) == 0) {
1860 ret
= qcow2_reopen_bitmaps_ro(state
->bs
, errp
);
1865 ret
= bdrv_flush(state
->bs
);
1870 ret
= qcow2_mark_clean(state
->bs
);
1879 qcow2_update_options_abort(state
->bs
, r
);
1884 static void qcow2_reopen_commit(BDRVReopenState
*state
)
1886 qcow2_update_options_commit(state
->bs
, state
->opaque
);
1887 g_free(state
->opaque
);
1890 static void qcow2_reopen_commit_post(BDRVReopenState
*state
)
1892 if (state
->flags
& BDRV_O_RDWR
) {
1893 Error
*local_err
= NULL
;
1895 if (qcow2_reopen_bitmaps_rw(state
->bs
, &local_err
) < 0) {
1897 * This is not fatal, bitmaps just left read-only, so all following
1898 * writes will fail. User can remove read-only bitmaps to unblock
1899 * writes or retry reopen.
1901 error_reportf_err(local_err
,
1902 "%s: Failed to make dirty bitmaps writable: ",
1903 bdrv_get_node_name(state
->bs
));
1908 static void qcow2_reopen_abort(BDRVReopenState
*state
)
1910 qcow2_update_options_abort(state
->bs
, state
->opaque
);
1911 g_free(state
->opaque
);
1914 static void qcow2_join_options(QDict
*options
, QDict
*old_options
)
1916 bool has_new_overlap_template
=
1917 qdict_haskey(options
, QCOW2_OPT_OVERLAP
) ||
1918 qdict_haskey(options
, QCOW2_OPT_OVERLAP_TEMPLATE
);
1919 bool has_new_total_cache_size
=
1920 qdict_haskey(options
, QCOW2_OPT_CACHE_SIZE
);
1921 bool has_all_cache_options
;
1923 /* New overlap template overrides all old overlap options */
1924 if (has_new_overlap_template
) {
1925 qdict_del(old_options
, QCOW2_OPT_OVERLAP
);
1926 qdict_del(old_options
, QCOW2_OPT_OVERLAP_TEMPLATE
);
1927 qdict_del(old_options
, QCOW2_OPT_OVERLAP_MAIN_HEADER
);
1928 qdict_del(old_options
, QCOW2_OPT_OVERLAP_ACTIVE_L1
);
1929 qdict_del(old_options
, QCOW2_OPT_OVERLAP_ACTIVE_L2
);
1930 qdict_del(old_options
, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
);
1931 qdict_del(old_options
, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
);
1932 qdict_del(old_options
, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
);
1933 qdict_del(old_options
, QCOW2_OPT_OVERLAP_INACTIVE_L1
);
1934 qdict_del(old_options
, QCOW2_OPT_OVERLAP_INACTIVE_L2
);
1937 /* New total cache size overrides all old options */
1938 if (qdict_haskey(options
, QCOW2_OPT_CACHE_SIZE
)) {
1939 qdict_del(old_options
, QCOW2_OPT_L2_CACHE_SIZE
);
1940 qdict_del(old_options
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
);
1943 qdict_join(options
, old_options
, false);
1946 * If after merging all cache size options are set, an old total size is
1947 * overwritten. Do keep all options, however, if all three are new. The
1948 * resulting error message is what we want to happen.
1950 has_all_cache_options
=
1951 qdict_haskey(options
, QCOW2_OPT_CACHE_SIZE
) ||
1952 qdict_haskey(options
, QCOW2_OPT_L2_CACHE_SIZE
) ||
1953 qdict_haskey(options
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
);
1955 if (has_all_cache_options
&& !has_new_total_cache_size
) {
1956 qdict_del(options
, QCOW2_OPT_CACHE_SIZE
);
1960 static int coroutine_fn
qcow2_co_block_status(BlockDriverState
*bs
,
1962 int64_t offset
, int64_t count
,
1963 int64_t *pnum
, int64_t *map
,
1964 BlockDriverState
**file
)
1966 BDRVQcow2State
*s
= bs
->opaque
;
1967 uint64_t cluster_offset
;
1969 int ret
, status
= 0;
1971 qemu_co_mutex_lock(&s
->lock
);
1973 if (!s
->metadata_preallocation_checked
) {
1974 ret
= qcow2_detect_metadata_preallocation(bs
);
1975 s
->metadata_preallocation
= (ret
== 1);
1976 s
->metadata_preallocation_checked
= true;
1979 bytes
= MIN(INT_MAX
, count
);
1980 ret
= qcow2_get_cluster_offset(bs
, offset
, &bytes
, &cluster_offset
);
1981 qemu_co_mutex_unlock(&s
->lock
);
1988 if ((ret
== QCOW2_CLUSTER_NORMAL
|| ret
== QCOW2_CLUSTER_ZERO_ALLOC
) &&
1990 *map
= cluster_offset
| offset_into_cluster(s
, offset
);
1991 *file
= s
->data_file
->bs
;
1992 status
|= BDRV_BLOCK_OFFSET_VALID
;
1994 if (ret
== QCOW2_CLUSTER_ZERO_PLAIN
|| ret
== QCOW2_CLUSTER_ZERO_ALLOC
) {
1995 status
|= BDRV_BLOCK_ZERO
;
1996 } else if (ret
!= QCOW2_CLUSTER_UNALLOCATED
) {
1997 status
|= BDRV_BLOCK_DATA
;
1999 if (s
->metadata_preallocation
&& (status
& BDRV_BLOCK_DATA
) &&
2000 (status
& BDRV_BLOCK_OFFSET_VALID
))
2002 status
|= BDRV_BLOCK_RECURSE
;
2007 static coroutine_fn
int qcow2_handle_l2meta(BlockDriverState
*bs
,
2008 QCowL2Meta
**pl2meta
,
2012 QCowL2Meta
*l2meta
= *pl2meta
;
2014 while (l2meta
!= NULL
) {
2018 ret
= qcow2_alloc_cluster_link_l2(bs
, l2meta
);
2023 qcow2_alloc_cluster_abort(bs
, l2meta
);
2026 /* Take the request off the list of running requests */
2027 if (l2meta
->nb_clusters
!= 0) {
2028 QLIST_REMOVE(l2meta
, next_in_flight
);
2031 qemu_co_queue_restart_all(&l2meta
->dependent_requests
);
2033 next
= l2meta
->next
;
2042 static coroutine_fn
int
2043 qcow2_co_preadv_encrypted(BlockDriverState
*bs
,
2044 uint64_t file_cluster_offset
,
2048 uint64_t qiov_offset
)
2051 BDRVQcow2State
*s
= bs
->opaque
;
2054 assert(bs
->encrypted
&& s
->crypto
);
2055 assert(bytes
<= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
2058 * For encrypted images, read everything into a temporary
2059 * contiguous buffer on which the AES functions can work.
2060 * Also, decryption in a separate buffer is better as it
2061 * prevents the guest from learning information about the
2062 * encrypted nature of the virtual disk.
2065 buf
= qemu_try_blockalign(s
->data_file
->bs
, bytes
);
2070 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_AIO
);
2071 ret
= bdrv_co_pread(s
->data_file
,
2072 file_cluster_offset
+ offset_into_cluster(s
, offset
),
2078 if (qcow2_co_decrypt(bs
,
2079 file_cluster_offset
+ offset_into_cluster(s
, offset
),
2080 offset
, buf
, bytes
) < 0)
2085 qemu_iovec_from_buf(qiov
, qiov_offset
, buf
, bytes
);
2093 typedef struct Qcow2AioTask
{
2096 BlockDriverState
*bs
;
2097 QCow2ClusterType cluster_type
; /* only for read */
2098 uint64_t file_cluster_offset
;
2102 uint64_t qiov_offset
;
2103 QCowL2Meta
*l2meta
; /* only for write */
2106 static coroutine_fn
int qcow2_co_preadv_task_entry(AioTask
*task
);
2107 static coroutine_fn
int qcow2_add_task(BlockDriverState
*bs
,
2110 QCow2ClusterType cluster_type
,
2111 uint64_t file_cluster_offset
,
2118 Qcow2AioTask local_task
;
2119 Qcow2AioTask
*task
= pool
? g_new(Qcow2AioTask
, 1) : &local_task
;
2121 *task
= (Qcow2AioTask
) {
2124 .cluster_type
= cluster_type
,
2126 .file_cluster_offset
= file_cluster_offset
,
2129 .qiov_offset
= qiov_offset
,
2133 trace_qcow2_add_task(qemu_coroutine_self(), bs
, pool
,
2134 func
== qcow2_co_preadv_task_entry
? "read" : "write",
2135 cluster_type
, file_cluster_offset
, offset
, bytes
,
2139 return func(&task
->task
);
2142 aio_task_pool_start_task(pool
, &task
->task
);
2147 static coroutine_fn
int qcow2_co_preadv_task(BlockDriverState
*bs
,
2148 QCow2ClusterType cluster_type
,
2149 uint64_t file_cluster_offset
,
2150 uint64_t offset
, uint64_t bytes
,
2154 BDRVQcow2State
*s
= bs
->opaque
;
2155 int offset_in_cluster
= offset_into_cluster(s
, offset
);
2157 switch (cluster_type
) {
2158 case QCOW2_CLUSTER_ZERO_PLAIN
:
2159 case QCOW2_CLUSTER_ZERO_ALLOC
:
2160 /* Both zero types are handled in qcow2_co_preadv_part */
2161 g_assert_not_reached();
2163 case QCOW2_CLUSTER_UNALLOCATED
:
2164 assert(bs
->backing
); /* otherwise handled in qcow2_co_preadv_part */
2166 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_BACKING_AIO
);
2167 return bdrv_co_preadv_part(bs
->backing
, offset
, bytes
,
2168 qiov
, qiov_offset
, 0);
2170 case QCOW2_CLUSTER_COMPRESSED
:
2171 return qcow2_co_preadv_compressed(bs
, file_cluster_offset
,
2172 offset
, bytes
, qiov
, qiov_offset
);
2174 case QCOW2_CLUSTER_NORMAL
:
2175 assert(offset_into_cluster(s
, file_cluster_offset
) == 0);
2176 if (bs
->encrypted
) {
2177 return qcow2_co_preadv_encrypted(bs
, file_cluster_offset
,
2178 offset
, bytes
, qiov
, qiov_offset
);
2181 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_AIO
);
2182 return bdrv_co_preadv_part(s
->data_file
,
2183 file_cluster_offset
+ offset_in_cluster
,
2184 bytes
, qiov
, qiov_offset
, 0);
2187 g_assert_not_reached();
2190 g_assert_not_reached();
2193 static coroutine_fn
int qcow2_co_preadv_task_entry(AioTask
*task
)
2195 Qcow2AioTask
*t
= container_of(task
, Qcow2AioTask
, task
);
2199 return qcow2_co_preadv_task(t
->bs
, t
->cluster_type
, t
->file_cluster_offset
,
2200 t
->offset
, t
->bytes
, t
->qiov
, t
->qiov_offset
);
2203 static coroutine_fn
int qcow2_co_preadv_part(BlockDriverState
*bs
,
2204 uint64_t offset
, uint64_t bytes
,
2206 size_t qiov_offset
, int flags
)
2208 BDRVQcow2State
*s
= bs
->opaque
;
2210 unsigned int cur_bytes
; /* number of bytes in current iteration */
2211 uint64_t cluster_offset
= 0;
2212 AioTaskPool
*aio
= NULL
;
2214 while (bytes
!= 0 && aio_task_pool_status(aio
) == 0) {
2215 /* prepare next request */
2216 cur_bytes
= MIN(bytes
, INT_MAX
);
2218 cur_bytes
= MIN(cur_bytes
,
2219 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
2222 qemu_co_mutex_lock(&s
->lock
);
2223 ret
= qcow2_get_cluster_offset(bs
, offset
, &cur_bytes
, &cluster_offset
);
2224 qemu_co_mutex_unlock(&s
->lock
);
2229 if (ret
== QCOW2_CLUSTER_ZERO_PLAIN
||
2230 ret
== QCOW2_CLUSTER_ZERO_ALLOC
||
2231 (ret
== QCOW2_CLUSTER_UNALLOCATED
&& !bs
->backing
))
2233 qemu_iovec_memset(qiov
, qiov_offset
, 0, cur_bytes
);
2235 if (!aio
&& cur_bytes
!= bytes
) {
2236 aio
= aio_task_pool_new(QCOW2_MAX_WORKERS
);
2238 ret
= qcow2_add_task(bs
, aio
, qcow2_co_preadv_task_entry
, ret
,
2239 cluster_offset
, offset
, cur_bytes
,
2240 qiov
, qiov_offset
, NULL
);
2247 offset
+= cur_bytes
;
2248 qiov_offset
+= cur_bytes
;
2253 aio_task_pool_wait_all(aio
);
2255 ret
= aio_task_pool_status(aio
);
2263 /* Check if it's possible to merge a write request with the writing of
2264 * the data from the COW regions */
2265 static bool merge_cow(uint64_t offset
, unsigned bytes
,
2266 QEMUIOVector
*qiov
, size_t qiov_offset
,
2271 for (m
= l2meta
; m
!= NULL
; m
= m
->next
) {
2272 /* If both COW regions are empty then there's nothing to merge */
2273 if (m
->cow_start
.nb_bytes
== 0 && m
->cow_end
.nb_bytes
== 0) {
2277 /* If COW regions are handled already, skip this too */
2282 /* The data (middle) region must be immediately after the
2284 if (l2meta_cow_start(m
) + m
->cow_start
.nb_bytes
!= offset
) {
2288 /* The end region must be immediately after the data (middle)
2290 if (m
->offset
+ m
->cow_end
.offset
!= offset
+ bytes
) {
2294 /* Make sure that adding both COW regions to the QEMUIOVector
2295 * does not exceed IOV_MAX */
2296 if (qemu_iovec_subvec_niov(qiov
, qiov_offset
, bytes
) > IOV_MAX
- 2) {
2300 m
->data_qiov
= qiov
;
2301 m
->data_qiov_offset
= qiov_offset
;
2308 static bool is_unallocated(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
)
2312 (!bdrv_is_allocated_above(bs
, NULL
, false, offset
, bytes
, &nr
) &&
2316 static bool is_zero_cow(BlockDriverState
*bs
, QCowL2Meta
*m
)
2319 * This check is designed for optimization shortcut so it must be
2321 * Instead of is_zero(), use is_unallocated() as it is faster (but not
2322 * as accurate and can result in false negatives).
2324 return is_unallocated(bs
, m
->offset
+ m
->cow_start
.offset
,
2325 m
->cow_start
.nb_bytes
) &&
2326 is_unallocated(bs
, m
->offset
+ m
->cow_end
.offset
,
2327 m
->cow_end
.nb_bytes
);
2330 static int handle_alloc_space(BlockDriverState
*bs
, QCowL2Meta
*l2meta
)
2332 BDRVQcow2State
*s
= bs
->opaque
;
2335 if (!(s
->data_file
->bs
->supported_zero_flags
& BDRV_REQ_NO_FALLBACK
)) {
2339 if (bs
->encrypted
) {
2343 for (m
= l2meta
; m
!= NULL
; m
= m
->next
) {
2346 if (!m
->cow_start
.nb_bytes
&& !m
->cow_end
.nb_bytes
) {
2350 if (!is_zero_cow(bs
, m
)) {
2355 * instead of writing zero COW buffers,
2356 * efficiently zero out the whole clusters
2359 ret
= qcow2_pre_write_overlap_check(bs
, 0, m
->alloc_offset
,
2360 m
->nb_clusters
* s
->cluster_size
,
2366 BLKDBG_EVENT(bs
->file
, BLKDBG_CLUSTER_ALLOC_SPACE
);
2367 ret
= bdrv_co_pwrite_zeroes(s
->data_file
, m
->alloc_offset
,
2368 m
->nb_clusters
* s
->cluster_size
,
2369 BDRV_REQ_NO_FALLBACK
);
2371 if (ret
!= -ENOTSUP
&& ret
!= -EAGAIN
) {
2377 trace_qcow2_skip_cow(qemu_coroutine_self(), m
->offset
, m
->nb_clusters
);
2384 * qcow2_co_pwritev_task
2385 * Called with s->lock unlocked
2386 * l2meta - if not NULL, qcow2_co_pwritev_task() will consume it. Caller must
2387 * not use it somehow after qcow2_co_pwritev_task() call
2389 static coroutine_fn
int qcow2_co_pwritev_task(BlockDriverState
*bs
,
2390 uint64_t file_cluster_offset
,
2391 uint64_t offset
, uint64_t bytes
,
2393 uint64_t qiov_offset
,
2397 BDRVQcow2State
*s
= bs
->opaque
;
2398 void *crypt_buf
= NULL
;
2399 int offset_in_cluster
= offset_into_cluster(s
, offset
);
2400 QEMUIOVector encrypted_qiov
;
2402 if (bs
->encrypted
) {
2404 assert(bytes
<= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
2405 crypt_buf
= qemu_try_blockalign(bs
->file
->bs
, bytes
);
2406 if (crypt_buf
== NULL
) {
2410 qemu_iovec_to_buf(qiov
, qiov_offset
, crypt_buf
, bytes
);
2412 if (qcow2_co_encrypt(bs
, file_cluster_offset
+ offset_in_cluster
,
2413 offset
, crypt_buf
, bytes
) < 0)
2419 qemu_iovec_init_buf(&encrypted_qiov
, crypt_buf
, bytes
);
2420 qiov
= &encrypted_qiov
;
2424 /* Try to efficiently initialize the physical space with zeroes */
2425 ret
= handle_alloc_space(bs
, l2meta
);
2431 * If we need to do COW, check if it's possible to merge the
2432 * writing of the guest data together with that of the COW regions.
2433 * If it's not possible (or not necessary) then write the
2436 if (!merge_cow(offset
, bytes
, qiov
, qiov_offset
, l2meta
)) {
2437 BLKDBG_EVENT(bs
->file
, BLKDBG_WRITE_AIO
);
2438 trace_qcow2_writev_data(qemu_coroutine_self(),
2439 file_cluster_offset
+ offset_in_cluster
);
2440 ret
= bdrv_co_pwritev_part(s
->data_file
,
2441 file_cluster_offset
+ offset_in_cluster
,
2442 bytes
, qiov
, qiov_offset
, 0);
2448 qemu_co_mutex_lock(&s
->lock
);
2450 ret
= qcow2_handle_l2meta(bs
, &l2meta
, true);
2454 qemu_co_mutex_lock(&s
->lock
);
2457 qcow2_handle_l2meta(bs
, &l2meta
, false);
2458 qemu_co_mutex_unlock(&s
->lock
);
2460 qemu_vfree(crypt_buf
);
2465 static coroutine_fn
int qcow2_co_pwritev_task_entry(AioTask
*task
)
2467 Qcow2AioTask
*t
= container_of(task
, Qcow2AioTask
, task
);
2469 assert(!t
->cluster_type
);
2471 return qcow2_co_pwritev_task(t
->bs
, t
->file_cluster_offset
,
2472 t
->offset
, t
->bytes
, t
->qiov
, t
->qiov_offset
,
2476 static coroutine_fn
int qcow2_co_pwritev_part(
2477 BlockDriverState
*bs
, uint64_t offset
, uint64_t bytes
,
2478 QEMUIOVector
*qiov
, size_t qiov_offset
, int flags
)
2480 BDRVQcow2State
*s
= bs
->opaque
;
2481 int offset_in_cluster
;
2483 unsigned int cur_bytes
; /* number of sectors in current iteration */
2484 uint64_t cluster_offset
;
2485 QCowL2Meta
*l2meta
= NULL
;
2486 AioTaskPool
*aio
= NULL
;
2488 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset
, bytes
);
2490 while (bytes
!= 0 && aio_task_pool_status(aio
) == 0) {
2494 trace_qcow2_writev_start_part(qemu_coroutine_self());
2495 offset_in_cluster
= offset_into_cluster(s
, offset
);
2496 cur_bytes
= MIN(bytes
, INT_MAX
);
2497 if (bs
->encrypted
) {
2498 cur_bytes
= MIN(cur_bytes
,
2499 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
2500 - offset_in_cluster
);
2503 qemu_co_mutex_lock(&s
->lock
);
2505 ret
= qcow2_alloc_cluster_offset(bs
, offset
, &cur_bytes
,
2506 &cluster_offset
, &l2meta
);
2511 assert(offset_into_cluster(s
, cluster_offset
) == 0);
2513 ret
= qcow2_pre_write_overlap_check(bs
, 0,
2514 cluster_offset
+ offset_in_cluster
,
2520 qemu_co_mutex_unlock(&s
->lock
);
2522 if (!aio
&& cur_bytes
!= bytes
) {
2523 aio
= aio_task_pool_new(QCOW2_MAX_WORKERS
);
2525 ret
= qcow2_add_task(bs
, aio
, qcow2_co_pwritev_task_entry
, 0,
2526 cluster_offset
, offset
, cur_bytes
,
2527 qiov
, qiov_offset
, l2meta
);
2528 l2meta
= NULL
; /* l2meta is consumed by qcow2_co_pwritev_task() */
2534 offset
+= cur_bytes
;
2535 qiov_offset
+= cur_bytes
;
2536 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes
);
2540 qemu_co_mutex_lock(&s
->lock
);
2543 qcow2_handle_l2meta(bs
, &l2meta
, false);
2545 qemu_co_mutex_unlock(&s
->lock
);
2549 aio_task_pool_wait_all(aio
);
2551 ret
= aio_task_pool_status(aio
);
2556 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret
);
2561 static int qcow2_inactivate(BlockDriverState
*bs
)
2563 BDRVQcow2State
*s
= bs
->opaque
;
2564 int ret
, result
= 0;
2565 Error
*local_err
= NULL
;
2567 qcow2_store_persistent_dirty_bitmaps(bs
, true, &local_err
);
2568 if (local_err
!= NULL
) {
2570 error_reportf_err(local_err
, "Lost persistent bitmaps during "
2571 "inactivation of node '%s': ",
2572 bdrv_get_device_or_node_name(bs
));
2575 ret
= qcow2_cache_flush(bs
, s
->l2_table_cache
);
2578 error_report("Failed to flush the L2 table cache: %s",
2582 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
2585 error_report("Failed to flush the refcount block cache: %s",
2590 qcow2_mark_clean(bs
);
2596 static void qcow2_close(BlockDriverState
*bs
)
2598 BDRVQcow2State
*s
= bs
->opaque
;
2599 qemu_vfree(s
->l1_table
);
2600 /* else pre-write overlap checks in cache_destroy may crash */
2603 if (!(s
->flags
& BDRV_O_INACTIVE
)) {
2604 qcow2_inactivate(bs
);
2607 cache_clean_timer_del(bs
);
2608 qcow2_cache_destroy(s
->l2_table_cache
);
2609 qcow2_cache_destroy(s
->refcount_block_cache
);
2611 qcrypto_block_free(s
->crypto
);
2614 g_free(s
->unknown_header_fields
);
2615 cleanup_unknown_header_ext(bs
);
2617 g_free(s
->image_data_file
);
2618 g_free(s
->image_backing_file
);
2619 g_free(s
->image_backing_format
);
2621 if (has_data_file(bs
)) {
2622 bdrv_unref_child(bs
, s
->data_file
);
2625 qcow2_refcount_close(bs
);
2626 qcow2_free_snapshots(bs
);
2629 static void coroutine_fn
qcow2_co_invalidate_cache(BlockDriverState
*bs
,
2632 BDRVQcow2State
*s
= bs
->opaque
;
2633 int flags
= s
->flags
;
2634 QCryptoBlock
*crypto
= NULL
;
2636 Error
*local_err
= NULL
;
2640 * Backing files are read-only which makes all of their metadata immutable,
2641 * that means we don't have to worry about reopening them here.
2649 memset(s
, 0, sizeof(BDRVQcow2State
));
2650 options
= qdict_clone_shallow(bs
->options
);
2652 flags
&= ~BDRV_O_INACTIVE
;
2653 qemu_co_mutex_lock(&s
->lock
);
2654 ret
= qcow2_do_open(bs
, options
, flags
, &local_err
);
2655 qemu_co_mutex_unlock(&s
->lock
);
2656 qobject_unref(options
);
2658 error_propagate_prepend(errp
, local_err
,
2659 "Could not reopen qcow2 layer: ");
2662 } else if (ret
< 0) {
2663 error_setg_errno(errp
, -ret
, "Could not reopen qcow2 layer");
2671 static size_t header_ext_add(char *buf
, uint32_t magic
, const void *s
,
2672 size_t len
, size_t buflen
)
2674 QCowExtension
*ext_backing_fmt
= (QCowExtension
*) buf
;
2675 size_t ext_len
= sizeof(QCowExtension
) + ((len
+ 7) & ~7);
2677 if (buflen
< ext_len
) {
2681 *ext_backing_fmt
= (QCowExtension
) {
2682 .magic
= cpu_to_be32(magic
),
2683 .len
= cpu_to_be32(len
),
2687 memcpy(buf
+ sizeof(QCowExtension
), s
, len
);
2694 * Updates the qcow2 header, including the variable length parts of it, i.e.
2695 * the backing file name and all extensions. qcow2 was not designed to allow
2696 * such changes, so if we run out of space (we can only use the first cluster)
2697 * this function may fail.
2699 * Returns 0 on success, -errno in error cases.
2701 int qcow2_update_header(BlockDriverState
*bs
)
2703 BDRVQcow2State
*s
= bs
->opaque
;
2706 size_t buflen
= s
->cluster_size
;
2708 uint64_t total_size
;
2709 uint32_t refcount_table_clusters
;
2710 size_t header_length
;
2711 Qcow2UnknownHeaderExtension
*uext
;
2713 buf
= qemu_blockalign(bs
, buflen
);
2715 /* Header structure */
2716 header
= (QCowHeader
*) buf
;
2718 if (buflen
< sizeof(*header
)) {
2723 header_length
= sizeof(*header
) + s
->unknown_header_fields_size
;
2724 total_size
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
2725 refcount_table_clusters
= s
->refcount_table_size
>> (s
->cluster_bits
- 3);
2727 *header
= (QCowHeader
) {
2728 /* Version 2 fields */
2729 .magic
= cpu_to_be32(QCOW_MAGIC
),
2730 .version
= cpu_to_be32(s
->qcow_version
),
2731 .backing_file_offset
= 0,
2732 .backing_file_size
= 0,
2733 .cluster_bits
= cpu_to_be32(s
->cluster_bits
),
2734 .size
= cpu_to_be64(total_size
),
2735 .crypt_method
= cpu_to_be32(s
->crypt_method_header
),
2736 .l1_size
= cpu_to_be32(s
->l1_size
),
2737 .l1_table_offset
= cpu_to_be64(s
->l1_table_offset
),
2738 .refcount_table_offset
= cpu_to_be64(s
->refcount_table_offset
),
2739 .refcount_table_clusters
= cpu_to_be32(refcount_table_clusters
),
2740 .nb_snapshots
= cpu_to_be32(s
->nb_snapshots
),
2741 .snapshots_offset
= cpu_to_be64(s
->snapshots_offset
),
2743 /* Version 3 fields */
2744 .incompatible_features
= cpu_to_be64(s
->incompatible_features
),
2745 .compatible_features
= cpu_to_be64(s
->compatible_features
),
2746 .autoclear_features
= cpu_to_be64(s
->autoclear_features
),
2747 .refcount_order
= cpu_to_be32(s
->refcount_order
),
2748 .header_length
= cpu_to_be32(header_length
),
2751 /* For older versions, write a shorter header */
2752 switch (s
->qcow_version
) {
2754 ret
= offsetof(QCowHeader
, incompatible_features
);
2757 ret
= sizeof(*header
);
2766 memset(buf
, 0, buflen
);
2768 /* Preserve any unknown field in the header */
2769 if (s
->unknown_header_fields_size
) {
2770 if (buflen
< s
->unknown_header_fields_size
) {
2775 memcpy(buf
, s
->unknown_header_fields
, s
->unknown_header_fields_size
);
2776 buf
+= s
->unknown_header_fields_size
;
2777 buflen
-= s
->unknown_header_fields_size
;
2780 /* Backing file format header extension */
2781 if (s
->image_backing_format
) {
2782 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_BACKING_FORMAT
,
2783 s
->image_backing_format
,
2784 strlen(s
->image_backing_format
),
2794 /* External data file header extension */
2795 if (has_data_file(bs
) && s
->image_data_file
) {
2796 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_DATA_FILE
,
2797 s
->image_data_file
, strlen(s
->image_data_file
),
2807 /* Full disk encryption header pointer extension */
2808 if (s
->crypto_header
.offset
!= 0) {
2809 s
->crypto_header
.offset
= cpu_to_be64(s
->crypto_header
.offset
);
2810 s
->crypto_header
.length
= cpu_to_be64(s
->crypto_header
.length
);
2811 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_CRYPTO_HEADER
,
2812 &s
->crypto_header
, sizeof(s
->crypto_header
),
2814 s
->crypto_header
.offset
= be64_to_cpu(s
->crypto_header
.offset
);
2815 s
->crypto_header
.length
= be64_to_cpu(s
->crypto_header
.length
);
2824 if (s
->qcow_version
>= 3) {
2825 Qcow2Feature features
[] = {
2827 .type
= QCOW2_FEAT_TYPE_INCOMPATIBLE
,
2828 .bit
= QCOW2_INCOMPAT_DIRTY_BITNR
,
2829 .name
= "dirty bit",
2832 .type
= QCOW2_FEAT_TYPE_INCOMPATIBLE
,
2833 .bit
= QCOW2_INCOMPAT_CORRUPT_BITNR
,
2834 .name
= "corrupt bit",
2837 .type
= QCOW2_FEAT_TYPE_INCOMPATIBLE
,
2838 .bit
= QCOW2_INCOMPAT_DATA_FILE_BITNR
,
2839 .name
= "external data file",
2842 .type
= QCOW2_FEAT_TYPE_COMPATIBLE
,
2843 .bit
= QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR
,
2844 .name
= "lazy refcounts",
2848 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_FEATURE_TABLE
,
2849 features
, sizeof(features
), buflen
);
2857 /* Bitmap extension */
2858 if (s
->nb_bitmaps
> 0) {
2859 Qcow2BitmapHeaderExt bitmaps_header
= {
2860 .nb_bitmaps
= cpu_to_be32(s
->nb_bitmaps
),
2861 .bitmap_directory_size
=
2862 cpu_to_be64(s
->bitmap_directory_size
),
2863 .bitmap_directory_offset
=
2864 cpu_to_be64(s
->bitmap_directory_offset
)
2866 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_BITMAPS
,
2867 &bitmaps_header
, sizeof(bitmaps_header
),
2876 /* Keep unknown header extensions */
2877 QLIST_FOREACH(uext
, &s
->unknown_header_ext
, next
) {
2878 ret
= header_ext_add(buf
, uext
->magic
, uext
->data
, uext
->len
, buflen
);
2887 /* End of header extensions */
2888 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_END
, NULL
, 0, buflen
);
2896 /* Backing file name */
2897 if (s
->image_backing_file
) {
2898 size_t backing_file_len
= strlen(s
->image_backing_file
);
2900 if (buflen
< backing_file_len
) {
2905 /* Using strncpy is ok here, since buf is not NUL-terminated. */
2906 strncpy(buf
, s
->image_backing_file
, buflen
);
2908 header
->backing_file_offset
= cpu_to_be64(buf
- ((char*) header
));
2909 header
->backing_file_size
= cpu_to_be32(backing_file_len
);
2912 /* Write the new header */
2913 ret
= bdrv_pwrite(bs
->file
, 0, header
, s
->cluster_size
);
2924 static int qcow2_change_backing_file(BlockDriverState
*bs
,
2925 const char *backing_file
, const char *backing_fmt
)
2927 BDRVQcow2State
*s
= bs
->opaque
;
2929 /* Adding a backing file means that the external data file alone won't be
2930 * enough to make sense of the content */
2931 if (backing_file
&& data_file_is_raw(bs
)) {
2935 if (backing_file
&& strlen(backing_file
) > 1023) {
2939 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
2940 backing_file
?: "");
2941 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
2942 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
2944 g_free(s
->image_backing_file
);
2945 g_free(s
->image_backing_format
);
2947 s
->image_backing_file
= backing_file
? g_strdup(bs
->backing_file
) : NULL
;
2948 s
->image_backing_format
= backing_fmt
? g_strdup(bs
->backing_format
) : NULL
;
2950 return qcow2_update_header(bs
);
2953 static int qcow2_crypt_method_from_format(const char *encryptfmt
)
2955 if (g_str_equal(encryptfmt
, "luks")) {
2956 return QCOW_CRYPT_LUKS
;
2957 } else if (g_str_equal(encryptfmt
, "aes")) {
2958 return QCOW_CRYPT_AES
;
2964 static int qcow2_set_up_encryption(BlockDriverState
*bs
,
2965 QCryptoBlockCreateOptions
*cryptoopts
,
2968 BDRVQcow2State
*s
= bs
->opaque
;
2969 QCryptoBlock
*crypto
= NULL
;
2972 switch (cryptoopts
->format
) {
2973 case Q_CRYPTO_BLOCK_FORMAT_LUKS
:
2974 fmt
= QCOW_CRYPT_LUKS
;
2976 case Q_CRYPTO_BLOCK_FORMAT_QCOW
:
2977 fmt
= QCOW_CRYPT_AES
;
2980 error_setg(errp
, "Crypto format not supported in qcow2");
2984 s
->crypt_method_header
= fmt
;
2986 crypto
= qcrypto_block_create(cryptoopts
, "encrypt.",
2987 qcow2_crypto_hdr_init_func
,
2988 qcow2_crypto_hdr_write_func
,
2994 ret
= qcow2_update_header(bs
);
2996 error_setg_errno(errp
, -ret
, "Could not write encryption header");
3002 qcrypto_block_free(crypto
);
3007 * Preallocates metadata structures for data clusters between @offset (in the
3008 * guest disk) and @new_length (which is thus generally the new guest disk
3011 * Returns: 0 on success, -errno on failure.
3013 static int coroutine_fn
preallocate_co(BlockDriverState
*bs
, uint64_t offset
,
3014 uint64_t new_length
, PreallocMode mode
,
3017 BDRVQcow2State
*s
= bs
->opaque
;
3019 uint64_t host_offset
= 0;
3020 int64_t file_length
;
3021 unsigned int cur_bytes
;
3025 assert(offset
<= new_length
);
3026 bytes
= new_length
- offset
;
3029 cur_bytes
= MIN(bytes
, QEMU_ALIGN_DOWN(INT_MAX
, s
->cluster_size
));
3030 ret
= qcow2_alloc_cluster_offset(bs
, offset
, &cur_bytes
,
3031 &host_offset
, &meta
);
3033 error_setg_errno(errp
, -ret
, "Allocating clusters failed");
3038 QCowL2Meta
*next
= meta
->next
;
3040 ret
= qcow2_alloc_cluster_link_l2(bs
, meta
);
3042 error_setg_errno(errp
, -ret
, "Mapping clusters failed");
3043 qcow2_free_any_clusters(bs
, meta
->alloc_offset
,
3044 meta
->nb_clusters
, QCOW2_DISCARD_NEVER
);
3048 /* There are no dependent requests, but we need to remove our
3049 * request from the list of in-flight requests */
3050 QLIST_REMOVE(meta
, next_in_flight
);
3056 /* TODO Preallocate data if requested */
3059 offset
+= cur_bytes
;
3063 * It is expected that the image file is large enough to actually contain
3064 * all of the allocated clusters (otherwise we get failing reads after
3065 * EOF). Extend the image to the last allocated sector.
3067 file_length
= bdrv_getlength(s
->data_file
->bs
);
3068 if (file_length
< 0) {
3069 error_setg_errno(errp
, -file_length
, "Could not get file size");
3073 if (host_offset
+ cur_bytes
> file_length
) {
3074 if (mode
== PREALLOC_MODE_METADATA
) {
3075 mode
= PREALLOC_MODE_OFF
;
3077 ret
= bdrv_co_truncate(s
->data_file
, host_offset
+ cur_bytes
, false,
3087 /* qcow2_refcount_metadata_size:
3088 * @clusters: number of clusters to refcount (including data and L1/L2 tables)
3089 * @cluster_size: size of a cluster, in bytes
3090 * @refcount_order: refcount bits power-of-2 exponent
3091 * @generous_increase: allow for the refcount table to be 1.5x as large as it
3094 * Returns: Number of bytes required for refcount blocks and table metadata.
3096 int64_t qcow2_refcount_metadata_size(int64_t clusters
, size_t cluster_size
,
3097 int refcount_order
, bool generous_increase
,
3098 uint64_t *refblock_count
)
3101 * Every host cluster is reference-counted, including metadata (even
3102 * refcount metadata is recursively included).
3104 * An accurate formula for the size of refcount metadata size is difficult
3105 * to derive. An easier method of calculation is finding the fixed point
3106 * where no further refcount blocks or table clusters are required to
3107 * reference count every cluster.
3109 int64_t blocks_per_table_cluster
= cluster_size
/ sizeof(uint64_t);
3110 int64_t refcounts_per_block
= cluster_size
* 8 / (1 << refcount_order
);
3111 int64_t table
= 0; /* number of refcount table clusters */
3112 int64_t blocks
= 0; /* number of refcount block clusters */
3118 blocks
= DIV_ROUND_UP(clusters
+ table
+ blocks
, refcounts_per_block
);
3119 table
= DIV_ROUND_UP(blocks
, blocks_per_table_cluster
);
3120 n
= clusters
+ blocks
+ table
;
3122 if (n
== last
&& generous_increase
) {
3123 clusters
+= DIV_ROUND_UP(table
, 2);
3124 n
= 0; /* force another loop */
3125 generous_increase
= false;
3127 } while (n
!= last
);
3129 if (refblock_count
) {
3130 *refblock_count
= blocks
;
3133 return (blocks
+ table
) * cluster_size
;
3137 * qcow2_calc_prealloc_size:
3138 * @total_size: virtual disk size in bytes
3139 * @cluster_size: cluster size in bytes
3140 * @refcount_order: refcount bits power-of-2 exponent
3142 * Returns: Total number of bytes required for the fully allocated image
3143 * (including metadata).
3145 static int64_t qcow2_calc_prealloc_size(int64_t total_size
,
3146 size_t cluster_size
,
3149 int64_t meta_size
= 0;
3150 uint64_t nl1e
, nl2e
;
3151 int64_t aligned_total_size
= ROUND_UP(total_size
, cluster_size
);
3153 /* header: 1 cluster */
3154 meta_size
+= cluster_size
;
3156 /* total size of L2 tables */
3157 nl2e
= aligned_total_size
/ cluster_size
;
3158 nl2e
= ROUND_UP(nl2e
, cluster_size
/ sizeof(uint64_t));
3159 meta_size
+= nl2e
* sizeof(uint64_t);
3161 /* total size of L1 tables */
3162 nl1e
= nl2e
* sizeof(uint64_t) / cluster_size
;
3163 nl1e
= ROUND_UP(nl1e
, cluster_size
/ sizeof(uint64_t));
3164 meta_size
+= nl1e
* sizeof(uint64_t);
3166 /* total size of refcount table and blocks */
3167 meta_size
+= qcow2_refcount_metadata_size(
3168 (meta_size
+ aligned_total_size
) / cluster_size
,
3169 cluster_size
, refcount_order
, false, NULL
);
3171 return meta_size
+ aligned_total_size
;
3174 static bool validate_cluster_size(size_t cluster_size
, Error
**errp
)
3176 int cluster_bits
= ctz32(cluster_size
);
3177 if (cluster_bits
< MIN_CLUSTER_BITS
|| cluster_bits
> MAX_CLUSTER_BITS
||
3178 (1 << cluster_bits
) != cluster_size
)
3180 error_setg(errp
, "Cluster size must be a power of two between %d and "
3181 "%dk", 1 << MIN_CLUSTER_BITS
, 1 << (MAX_CLUSTER_BITS
- 10));
3187 static size_t qcow2_opt_get_cluster_size_del(QemuOpts
*opts
, Error
**errp
)
3189 size_t cluster_size
;
3191 cluster_size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_CLUSTER_SIZE
,
3192 DEFAULT_CLUSTER_SIZE
);
3193 if (!validate_cluster_size(cluster_size
, errp
)) {
3196 return cluster_size
;
3199 static int qcow2_opt_get_version_del(QemuOpts
*opts
, Error
**errp
)
3204 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_COMPAT_LEVEL
);
3206 ret
= 3; /* default */
3207 } else if (!strcmp(buf
, "0.10")) {
3209 } else if (!strcmp(buf
, "1.1")) {
3212 error_setg(errp
, "Invalid compatibility level: '%s'", buf
);
3219 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts
*opts
, int version
,
3222 uint64_t refcount_bits
;
3224 refcount_bits
= qemu_opt_get_number_del(opts
, BLOCK_OPT_REFCOUNT_BITS
, 16);
3225 if (refcount_bits
> 64 || !is_power_of_2(refcount_bits
)) {
3226 error_setg(errp
, "Refcount width must be a power of two and may not "
3231 if (version
< 3 && refcount_bits
!= 16) {
3232 error_setg(errp
, "Different refcount widths than 16 bits require "
3233 "compatibility level 1.1 or above (use compat=1.1 or "
3238 return refcount_bits
;
3241 static int coroutine_fn
3242 qcow2_co_create(BlockdevCreateOptions
*create_options
, Error
**errp
)
3244 BlockdevCreateOptionsQcow2
*qcow2_opts
;
3248 * Open the image file and write a minimal qcow2 header.
3250 * We keep things simple and start with a zero-sized image. We also
3251 * do without refcount blocks or a L1 table for now. We'll fix the
3252 * inconsistency later.
3254 * We do need a refcount table because growing the refcount table means
3255 * allocating two new refcount blocks - the seconds of which would be at
3256 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
3257 * size for any qcow2 image.
3259 BlockBackend
*blk
= NULL
;
3260 BlockDriverState
*bs
= NULL
;
3261 BlockDriverState
*data_bs
= NULL
;
3263 size_t cluster_size
;
3266 uint64_t* refcount_table
;
3267 Error
*local_err
= NULL
;
3270 assert(create_options
->driver
== BLOCKDEV_DRIVER_QCOW2
);
3271 qcow2_opts
= &create_options
->u
.qcow2
;
3273 bs
= bdrv_open_blockdev_ref(qcow2_opts
->file
, errp
);
3278 /* Validate options and set default values */
3279 if (!QEMU_IS_ALIGNED(qcow2_opts
->size
, BDRV_SECTOR_SIZE
)) {
3280 error_setg(errp
, "Image size must be a multiple of %u bytes",
3281 (unsigned) BDRV_SECTOR_SIZE
);
3286 if (qcow2_opts
->has_version
) {
3287 switch (qcow2_opts
->version
) {
3288 case BLOCKDEV_QCOW2_VERSION_V2
:
3291 case BLOCKDEV_QCOW2_VERSION_V3
:
3295 g_assert_not_reached();
3301 if (qcow2_opts
->has_cluster_size
) {
3302 cluster_size
= qcow2_opts
->cluster_size
;
3304 cluster_size
= DEFAULT_CLUSTER_SIZE
;
3307 if (!validate_cluster_size(cluster_size
, errp
)) {
3312 if (!qcow2_opts
->has_preallocation
) {
3313 qcow2_opts
->preallocation
= PREALLOC_MODE_OFF
;
3315 if (qcow2_opts
->has_backing_file
&&
3316 qcow2_opts
->preallocation
!= PREALLOC_MODE_OFF
)
3318 error_setg(errp
, "Backing file and preallocation cannot be used at "
3323 if (qcow2_opts
->has_backing_fmt
&& !qcow2_opts
->has_backing_file
) {
3324 error_setg(errp
, "Backing format cannot be used without backing file");
3329 if (!qcow2_opts
->has_lazy_refcounts
) {
3330 qcow2_opts
->lazy_refcounts
= false;
3332 if (version
< 3 && qcow2_opts
->lazy_refcounts
) {
3333 error_setg(errp
, "Lazy refcounts only supported with compatibility "
3334 "level 1.1 and above (use version=v3 or greater)");
3339 if (!qcow2_opts
->has_refcount_bits
) {
3340 qcow2_opts
->refcount_bits
= 16;
3342 if (qcow2_opts
->refcount_bits
> 64 ||
3343 !is_power_of_2(qcow2_opts
->refcount_bits
))
3345 error_setg(errp
, "Refcount width must be a power of two and may not "
3350 if (version
< 3 && qcow2_opts
->refcount_bits
!= 16) {
3351 error_setg(errp
, "Different refcount widths than 16 bits require "
3352 "compatibility level 1.1 or above (use version=v3 or "
3357 refcount_order
= ctz32(qcow2_opts
->refcount_bits
);
3359 if (qcow2_opts
->data_file_raw
&& !qcow2_opts
->data_file
) {
3360 error_setg(errp
, "data-file-raw requires data-file");
3364 if (qcow2_opts
->data_file_raw
&& qcow2_opts
->has_backing_file
) {
3365 error_setg(errp
, "Backing file and data-file-raw cannot be used at "
3371 if (qcow2_opts
->data_file
) {
3373 error_setg(errp
, "External data files are only supported with "
3374 "compatibility level 1.1 and above (use version=v3 or "
3379 data_bs
= bdrv_open_blockdev_ref(qcow2_opts
->data_file
, errp
);
3380 if (data_bs
== NULL
) {
3386 /* Create BlockBackend to write to the image */
3387 blk
= blk_new(bdrv_get_aio_context(bs
),
3388 BLK_PERM_WRITE
| BLK_PERM_RESIZE
, BLK_PERM_ALL
);
3389 ret
= blk_insert_bs(blk
, bs
, errp
);
3393 blk_set_allow_write_beyond_eof(blk
, true);
3395 /* Write the header */
3396 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS
) < sizeof(*header
));
3397 header
= g_malloc0(cluster_size
);
3398 *header
= (QCowHeader
) {
3399 .magic
= cpu_to_be32(QCOW_MAGIC
),
3400 .version
= cpu_to_be32(version
),
3401 .cluster_bits
= cpu_to_be32(ctz32(cluster_size
)),
3402 .size
= cpu_to_be64(0),
3403 .l1_table_offset
= cpu_to_be64(0),
3404 .l1_size
= cpu_to_be32(0),
3405 .refcount_table_offset
= cpu_to_be64(cluster_size
),
3406 .refcount_table_clusters
= cpu_to_be32(1),
3407 .refcount_order
= cpu_to_be32(refcount_order
),
3408 .header_length
= cpu_to_be32(sizeof(*header
)),
3411 /* We'll update this to correct value later */
3412 header
->crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
3414 if (qcow2_opts
->lazy_refcounts
) {
3415 header
->compatible_features
|=
3416 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS
);
3419 header
->incompatible_features
|=
3420 cpu_to_be64(QCOW2_INCOMPAT_DATA_FILE
);
3422 if (qcow2_opts
->data_file_raw
) {
3423 header
->autoclear_features
|=
3424 cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW
);
3427 ret
= blk_pwrite(blk
, 0, header
, cluster_size
, 0);
3430 error_setg_errno(errp
, -ret
, "Could not write qcow2 header");
3434 /* Write a refcount table with one refcount block */
3435 refcount_table
= g_malloc0(2 * cluster_size
);
3436 refcount_table
[0] = cpu_to_be64(2 * cluster_size
);
3437 ret
= blk_pwrite(blk
, cluster_size
, refcount_table
, 2 * cluster_size
, 0);
3438 g_free(refcount_table
);
3441 error_setg_errno(errp
, -ret
, "Could not write refcount table");
3449 * And now open the image and make it consistent first (i.e. increase the
3450 * refcount of the cluster that is occupied by the header and the refcount
3453 options
= qdict_new();
3454 qdict_put_str(options
, "driver", "qcow2");
3455 qdict_put_str(options
, "file", bs
->node_name
);
3457 qdict_put_str(options
, "data-file", data_bs
->node_name
);
3459 blk
= blk_new_open(NULL
, NULL
, options
,
3460 BDRV_O_RDWR
| BDRV_O_RESIZE
| BDRV_O_NO_FLUSH
,
3463 error_propagate(errp
, local_err
);
3468 ret
= qcow2_alloc_clusters(blk_bs(blk
), 3 * cluster_size
);
3470 error_setg_errno(errp
, -ret
, "Could not allocate clusters for qcow2 "
3471 "header and refcount table");
3474 } else if (ret
!= 0) {
3475 error_report("Huh, first cluster in empty image is already in use?");
3479 /* Set the external data file if necessary */
3481 BDRVQcow2State
*s
= blk_bs(blk
)->opaque
;
3482 s
->image_data_file
= g_strdup(data_bs
->filename
);
3485 /* Create a full header (including things like feature table) */
3486 ret
= qcow2_update_header(blk_bs(blk
));
3488 error_setg_errno(errp
, -ret
, "Could not update qcow2 header");
3492 /* Okay, now that we have a valid image, let's give it the right size */
3493 ret
= blk_truncate(blk
, qcow2_opts
->size
, false, qcow2_opts
->preallocation
,
3496 error_prepend(errp
, "Could not resize image: ");
3500 /* Want a backing file? There you go.*/
3501 if (qcow2_opts
->has_backing_file
) {
3502 const char *backing_format
= NULL
;
3504 if (qcow2_opts
->has_backing_fmt
) {
3505 backing_format
= BlockdevDriver_str(qcow2_opts
->backing_fmt
);
3508 ret
= bdrv_change_backing_file(blk_bs(blk
), qcow2_opts
->backing_file
,
3511 error_setg_errno(errp
, -ret
, "Could not assign backing file '%s' "
3512 "with format '%s'", qcow2_opts
->backing_file
,
3518 /* Want encryption? There you go. */
3519 if (qcow2_opts
->has_encrypt
) {
3520 ret
= qcow2_set_up_encryption(blk_bs(blk
), qcow2_opts
->encrypt
, errp
);
3529 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning.
3530 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to
3531 * have to setup decryption context. We're not doing any I/O on the top
3532 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does
3535 options
= qdict_new();
3536 qdict_put_str(options
, "driver", "qcow2");
3537 qdict_put_str(options
, "file", bs
->node_name
);
3539 qdict_put_str(options
, "data-file", data_bs
->node_name
);
3541 blk
= blk_new_open(NULL
, NULL
, options
,
3542 BDRV_O_RDWR
| BDRV_O_NO_BACKING
| BDRV_O_NO_IO
,
3545 error_propagate(errp
, local_err
);
3554 bdrv_unref(data_bs
);
3558 static int coroutine_fn
qcow2_co_create_opts(const char *filename
, QemuOpts
*opts
,
3561 BlockdevCreateOptions
*create_options
= NULL
;
3564 BlockDriverState
*bs
= NULL
;
3565 BlockDriverState
*data_bs
= NULL
;
3566 Error
*local_err
= NULL
;
3570 /* Only the keyval visitor supports the dotted syntax needed for
3571 * encryption, so go through a QDict before getting a QAPI type. Ignore
3572 * options meant for the protocol layer so that the visitor doesn't
3574 qdict
= qemu_opts_to_qdict_filtered(opts
, NULL
, bdrv_qcow2
.create_opts
,
3577 /* Handle encryption options */
3578 val
= qdict_get_try_str(qdict
, BLOCK_OPT_ENCRYPT
);
3579 if (val
&& !strcmp(val
, "on")) {
3580 qdict_put_str(qdict
, BLOCK_OPT_ENCRYPT
, "qcow");
3581 } else if (val
&& !strcmp(val
, "off")) {
3582 qdict_del(qdict
, BLOCK_OPT_ENCRYPT
);
3585 val
= qdict_get_try_str(qdict
, BLOCK_OPT_ENCRYPT_FORMAT
);
3586 if (val
&& !strcmp(val
, "aes")) {
3587 qdict_put_str(qdict
, BLOCK_OPT_ENCRYPT_FORMAT
, "qcow");
3590 /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into
3591 * version=v2/v3 below. */
3592 val
= qdict_get_try_str(qdict
, BLOCK_OPT_COMPAT_LEVEL
);
3593 if (val
&& !strcmp(val
, "0.10")) {
3594 qdict_put_str(qdict
, BLOCK_OPT_COMPAT_LEVEL
, "v2");
3595 } else if (val
&& !strcmp(val
, "1.1")) {
3596 qdict_put_str(qdict
, BLOCK_OPT_COMPAT_LEVEL
, "v3");
3599 /* Change legacy command line options into QMP ones */
3600 static const QDictRenames opt_renames
[] = {
3601 { BLOCK_OPT_BACKING_FILE
, "backing-file" },
3602 { BLOCK_OPT_BACKING_FMT
, "backing-fmt" },
3603 { BLOCK_OPT_CLUSTER_SIZE
, "cluster-size" },
3604 { BLOCK_OPT_LAZY_REFCOUNTS
, "lazy-refcounts" },
3605 { BLOCK_OPT_REFCOUNT_BITS
, "refcount-bits" },
3606 { BLOCK_OPT_ENCRYPT
, BLOCK_OPT_ENCRYPT_FORMAT
},
3607 { BLOCK_OPT_COMPAT_LEVEL
, "version" },
3608 { BLOCK_OPT_DATA_FILE_RAW
, "data-file-raw" },
3612 if (!qdict_rename_keys(qdict
, opt_renames
, errp
)) {
3617 /* Create and open the file (protocol layer) */
3618 ret
= bdrv_create_file(filename
, opts
, errp
);
3623 bs
= bdrv_open(filename
, NULL
, NULL
,
3624 BDRV_O_RDWR
| BDRV_O_RESIZE
| BDRV_O_PROTOCOL
, errp
);
3630 /* Create and open an external data file (protocol layer) */
3631 val
= qdict_get_try_str(qdict
, BLOCK_OPT_DATA_FILE
);
3633 ret
= bdrv_create_file(val
, opts
, errp
);
3638 data_bs
= bdrv_open(val
, NULL
, NULL
,
3639 BDRV_O_RDWR
| BDRV_O_RESIZE
| BDRV_O_PROTOCOL
,
3641 if (data_bs
== NULL
) {
3646 qdict_del(qdict
, BLOCK_OPT_DATA_FILE
);
3647 qdict_put_str(qdict
, "data-file", data_bs
->node_name
);
3650 /* Set 'driver' and 'node' options */
3651 qdict_put_str(qdict
, "driver", "qcow2");
3652 qdict_put_str(qdict
, "file", bs
->node_name
);
3654 /* Now get the QAPI type BlockdevCreateOptions */
3655 v
= qobject_input_visitor_new_flat_confused(qdict
, errp
);
3661 visit_type_BlockdevCreateOptions(v
, NULL
, &create_options
, &local_err
);
3665 error_propagate(errp
, local_err
);
3670 /* Silently round up size */
3671 create_options
->u
.qcow2
.size
= ROUND_UP(create_options
->u
.qcow2
.size
,
3674 /* Create the qcow2 image (format layer) */
3675 ret
= qcow2_co_create(create_options
, errp
);
3682 qobject_unref(qdict
);
3684 bdrv_unref(data_bs
);
3685 qapi_free_BlockdevCreateOptions(create_options
);
3690 static bool is_zero(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
)
3695 /* Clamp to image length, before checking status of underlying sectors */
3696 if (offset
+ bytes
> bs
->total_sectors
* BDRV_SECTOR_SIZE
) {
3697 bytes
= bs
->total_sectors
* BDRV_SECTOR_SIZE
- offset
;
3703 res
= bdrv_block_status_above(bs
, NULL
, offset
, bytes
, &nr
, NULL
, NULL
);
3704 return res
>= 0 && (res
& BDRV_BLOCK_ZERO
) && nr
== bytes
;
3707 static coroutine_fn
int qcow2_co_pwrite_zeroes(BlockDriverState
*bs
,
3708 int64_t offset
, int bytes
, BdrvRequestFlags flags
)
3711 BDRVQcow2State
*s
= bs
->opaque
;
3713 uint32_t head
= offset
% s
->cluster_size
;
3714 uint32_t tail
= (offset
+ bytes
) % s
->cluster_size
;
3716 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset
, bytes
);
3717 if (offset
+ bytes
== bs
->total_sectors
* BDRV_SECTOR_SIZE
) {
3725 assert(head
+ bytes
<= s
->cluster_size
);
3727 /* check whether remainder of cluster already reads as zero */
3728 if (!(is_zero(bs
, offset
- head
, head
) &&
3729 is_zero(bs
, offset
+ bytes
,
3730 tail
? s
->cluster_size
- tail
: 0))) {
3734 qemu_co_mutex_lock(&s
->lock
);
3735 /* We can have new write after previous check */
3736 offset
= QEMU_ALIGN_DOWN(offset
, s
->cluster_size
);
3737 bytes
= s
->cluster_size
;
3738 nr
= s
->cluster_size
;
3739 ret
= qcow2_get_cluster_offset(bs
, offset
, &nr
, &off
);
3740 if (ret
!= QCOW2_CLUSTER_UNALLOCATED
&&
3741 ret
!= QCOW2_CLUSTER_ZERO_PLAIN
&&
3742 ret
!= QCOW2_CLUSTER_ZERO_ALLOC
) {
3743 qemu_co_mutex_unlock(&s
->lock
);
3747 qemu_co_mutex_lock(&s
->lock
);
3750 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset
, bytes
);
3752 /* Whatever is left can use real zero clusters */
3753 ret
= qcow2_cluster_zeroize(bs
, offset
, bytes
, flags
);
3754 qemu_co_mutex_unlock(&s
->lock
);
3759 static coroutine_fn
int qcow2_co_pdiscard(BlockDriverState
*bs
,
3760 int64_t offset
, int bytes
)
3763 BDRVQcow2State
*s
= bs
->opaque
;
3765 if (!QEMU_IS_ALIGNED(offset
| bytes
, s
->cluster_size
)) {
3766 assert(bytes
< s
->cluster_size
);
3767 /* Ignore partial clusters, except for the special case of the
3768 * complete partial cluster at the end of an unaligned file */
3769 if (!QEMU_IS_ALIGNED(offset
, s
->cluster_size
) ||
3770 offset
+ bytes
!= bs
->total_sectors
* BDRV_SECTOR_SIZE
) {
3775 qemu_co_mutex_lock(&s
->lock
);
3776 ret
= qcow2_cluster_discard(bs
, offset
, bytes
, QCOW2_DISCARD_REQUEST
,
3778 qemu_co_mutex_unlock(&s
->lock
);
3782 static int coroutine_fn
3783 qcow2_co_copy_range_from(BlockDriverState
*bs
,
3784 BdrvChild
*src
, uint64_t src_offset
,
3785 BdrvChild
*dst
, uint64_t dst_offset
,
3786 uint64_t bytes
, BdrvRequestFlags read_flags
,
3787 BdrvRequestFlags write_flags
)
3789 BDRVQcow2State
*s
= bs
->opaque
;
3791 unsigned int cur_bytes
; /* number of bytes in current iteration */
3792 BdrvChild
*child
= NULL
;
3793 BdrvRequestFlags cur_write_flags
;
3795 assert(!bs
->encrypted
);
3796 qemu_co_mutex_lock(&s
->lock
);
3798 while (bytes
!= 0) {
3799 uint64_t copy_offset
= 0;
3800 /* prepare next request */
3801 cur_bytes
= MIN(bytes
, INT_MAX
);
3802 cur_write_flags
= write_flags
;
3804 ret
= qcow2_get_cluster_offset(bs
, src_offset
, &cur_bytes
, ©_offset
);
3810 case QCOW2_CLUSTER_UNALLOCATED
:
3811 if (bs
->backing
&& bs
->backing
->bs
) {
3812 int64_t backing_length
= bdrv_getlength(bs
->backing
->bs
);
3813 if (src_offset
>= backing_length
) {
3814 cur_write_flags
|= BDRV_REQ_ZERO_WRITE
;
3816 child
= bs
->backing
;
3817 cur_bytes
= MIN(cur_bytes
, backing_length
- src_offset
);
3818 copy_offset
= src_offset
;
3821 cur_write_flags
|= BDRV_REQ_ZERO_WRITE
;
3825 case QCOW2_CLUSTER_ZERO_PLAIN
:
3826 case QCOW2_CLUSTER_ZERO_ALLOC
:
3827 cur_write_flags
|= BDRV_REQ_ZERO_WRITE
;
3830 case QCOW2_CLUSTER_COMPRESSED
:
3834 case QCOW2_CLUSTER_NORMAL
:
3835 child
= s
->data_file
;
3836 copy_offset
+= offset_into_cluster(s
, src_offset
);
3842 qemu_co_mutex_unlock(&s
->lock
);
3843 ret
= bdrv_co_copy_range_from(child
,
3846 cur_bytes
, read_flags
, cur_write_flags
);
3847 qemu_co_mutex_lock(&s
->lock
);
3853 src_offset
+= cur_bytes
;
3854 dst_offset
+= cur_bytes
;
3859 qemu_co_mutex_unlock(&s
->lock
);
3863 static int coroutine_fn
3864 qcow2_co_copy_range_to(BlockDriverState
*bs
,
3865 BdrvChild
*src
, uint64_t src_offset
,
3866 BdrvChild
*dst
, uint64_t dst_offset
,
3867 uint64_t bytes
, BdrvRequestFlags read_flags
,
3868 BdrvRequestFlags write_flags
)
3870 BDRVQcow2State
*s
= bs
->opaque
;
3871 int offset_in_cluster
;
3873 unsigned int cur_bytes
; /* number of sectors in current iteration */
3874 uint64_t cluster_offset
;
3875 QCowL2Meta
*l2meta
= NULL
;
3877 assert(!bs
->encrypted
);
3879 qemu_co_mutex_lock(&s
->lock
);
3881 while (bytes
!= 0) {
3885 offset_in_cluster
= offset_into_cluster(s
, dst_offset
);
3886 cur_bytes
= MIN(bytes
, INT_MAX
);
3889 * If src->bs == dst->bs, we could simply copy by incrementing
3890 * the refcnt, without copying user data.
3891 * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */
3892 ret
= qcow2_alloc_cluster_offset(bs
, dst_offset
, &cur_bytes
,
3893 &cluster_offset
, &l2meta
);
3898 assert(offset_into_cluster(s
, cluster_offset
) == 0);
3900 ret
= qcow2_pre_write_overlap_check(bs
, 0,
3901 cluster_offset
+ offset_in_cluster
, cur_bytes
, true);
3906 qemu_co_mutex_unlock(&s
->lock
);
3907 ret
= bdrv_co_copy_range_to(src
, src_offset
,
3909 cluster_offset
+ offset_in_cluster
,
3910 cur_bytes
, read_flags
, write_flags
);
3911 qemu_co_mutex_lock(&s
->lock
);
3916 ret
= qcow2_handle_l2meta(bs
, &l2meta
, true);
3922 src_offset
+= cur_bytes
;
3923 dst_offset
+= cur_bytes
;
3928 qcow2_handle_l2meta(bs
, &l2meta
, false);
3930 qemu_co_mutex_unlock(&s
->lock
);
3932 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret
);
3937 static int coroutine_fn
qcow2_co_truncate(BlockDriverState
*bs
, int64_t offset
,
3938 bool exact
, PreallocMode prealloc
,
3941 BDRVQcow2State
*s
= bs
->opaque
;
3942 uint64_t old_length
;
3943 int64_t new_l1_size
;
3947 if (prealloc
!= PREALLOC_MODE_OFF
&& prealloc
!= PREALLOC_MODE_METADATA
&&
3948 prealloc
!= PREALLOC_MODE_FALLOC
&& prealloc
!= PREALLOC_MODE_FULL
)
3950 error_setg(errp
, "Unsupported preallocation mode '%s'",
3951 PreallocMode_str(prealloc
));
3955 if (!QEMU_IS_ALIGNED(offset
, BDRV_SECTOR_SIZE
)) {
3956 error_setg(errp
, "The new size must be a multiple of %u",
3957 (unsigned) BDRV_SECTOR_SIZE
);
3961 qemu_co_mutex_lock(&s
->lock
);
3963 /* cannot proceed if image has snapshots */
3964 if (s
->nb_snapshots
) {
3965 error_setg(errp
, "Can't resize an image which has snapshots");
3970 /* cannot proceed if image has bitmaps */
3971 if (qcow2_truncate_bitmaps_check(bs
, errp
)) {
3976 old_length
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
3977 new_l1_size
= size_to_l1(s
, offset
);
3979 if (offset
< old_length
) {
3980 int64_t last_cluster
, old_file_size
;
3981 if (prealloc
!= PREALLOC_MODE_OFF
) {
3983 "Preallocation can't be used for shrinking an image");
3988 ret
= qcow2_cluster_discard(bs
, ROUND_UP(offset
, s
->cluster_size
),
3989 old_length
- ROUND_UP(offset
,
3991 QCOW2_DISCARD_ALWAYS
, true);
3993 error_setg_errno(errp
, -ret
, "Failed to discard cropped clusters");
3997 ret
= qcow2_shrink_l1_table(bs
, new_l1_size
);
3999 error_setg_errno(errp
, -ret
,
4000 "Failed to reduce the number of L2 tables");
4004 ret
= qcow2_shrink_reftable(bs
);
4006 error_setg_errno(errp
, -ret
,
4007 "Failed to discard unused refblocks");
4011 old_file_size
= bdrv_getlength(bs
->file
->bs
);
4012 if (old_file_size
< 0) {
4013 error_setg_errno(errp
, -old_file_size
,
4014 "Failed to inquire current file length");
4015 ret
= old_file_size
;
4018 last_cluster
= qcow2_get_last_cluster(bs
, old_file_size
);
4019 if (last_cluster
< 0) {
4020 error_setg_errno(errp
, -last_cluster
,
4021 "Failed to find the last cluster");
4025 if ((last_cluster
+ 1) * s
->cluster_size
< old_file_size
) {
4026 Error
*local_err
= NULL
;
4029 * Do not pass @exact here: It will not help the user if
4030 * we get an error here just because they wanted to shrink
4031 * their qcow2 image (on a block device) with qemu-img.
4032 * (And on the qcow2 layer, the @exact requirement is
4033 * always fulfilled, so there is no need to pass it on.)
4035 bdrv_co_truncate(bs
->file
, (last_cluster
+ 1) * s
->cluster_size
,
4036 false, PREALLOC_MODE_OFF
, &local_err
);
4038 warn_reportf_err(local_err
,
4039 "Failed to truncate the tail of the image: ");
4043 ret
= qcow2_grow_l1_table(bs
, new_l1_size
, true);
4045 error_setg_errno(errp
, -ret
, "Failed to grow the L1 table");
4051 case PREALLOC_MODE_OFF
:
4052 if (has_data_file(bs
)) {
4054 * If the caller wants an exact resize, the external data
4055 * file should be resized to the exact target size, too,
4056 * so we pass @exact here.
4058 ret
= bdrv_co_truncate(s
->data_file
, offset
, exact
, prealloc
, errp
);
4065 case PREALLOC_MODE_METADATA
:
4066 ret
= preallocate_co(bs
, old_length
, offset
, prealloc
, errp
);
4072 case PREALLOC_MODE_FALLOC
:
4073 case PREALLOC_MODE_FULL
:
4075 int64_t allocation_start
, host_offset
, guest_offset
;
4076 int64_t clusters_allocated
;
4077 int64_t old_file_size
, new_file_size
;
4078 uint64_t nb_new_data_clusters
, nb_new_l2_tables
;
4080 /* With a data file, preallocation means just allocating the metadata
4081 * and forwarding the truncate request to the data file */
4082 if (has_data_file(bs
)) {
4083 ret
= preallocate_co(bs
, old_length
, offset
, prealloc
, errp
);
4090 old_file_size
= bdrv_getlength(bs
->file
->bs
);
4091 if (old_file_size
< 0) {
4092 error_setg_errno(errp
, -old_file_size
,
4093 "Failed to inquire current file length");
4094 ret
= old_file_size
;
4097 old_file_size
= ROUND_UP(old_file_size
, s
->cluster_size
);
4099 nb_new_data_clusters
= DIV_ROUND_UP(offset
- old_length
,
4102 /* This is an overestimation; we will not actually allocate space for
4103 * these in the file but just make sure the new refcount structures are
4104 * able to cover them so we will not have to allocate new refblocks
4105 * while entering the data blocks in the potentially new L2 tables.
4106 * (We do not actually care where the L2 tables are placed. Maybe they
4107 * are already allocated or they can be placed somewhere before
4108 * @old_file_size. It does not matter because they will be fully
4109 * allocated automatically, so they do not need to be covered by the
4110 * preallocation. All that matters is that we will not have to allocate
4111 * new refcount structures for them.) */
4112 nb_new_l2_tables
= DIV_ROUND_UP(nb_new_data_clusters
,
4113 s
->cluster_size
/ sizeof(uint64_t));
4114 /* The cluster range may not be aligned to L2 boundaries, so add one L2
4115 * table for a potential head/tail */
4118 allocation_start
= qcow2_refcount_area(bs
, old_file_size
,
4119 nb_new_data_clusters
+
4122 if (allocation_start
< 0) {
4123 error_setg_errno(errp
, -allocation_start
,
4124 "Failed to resize refcount structures");
4125 ret
= allocation_start
;
4129 clusters_allocated
= qcow2_alloc_clusters_at(bs
, allocation_start
,
4130 nb_new_data_clusters
);
4131 if (clusters_allocated
< 0) {
4132 error_setg_errno(errp
, -clusters_allocated
,
4133 "Failed to allocate data clusters");
4134 ret
= clusters_allocated
;
4138 assert(clusters_allocated
== nb_new_data_clusters
);
4140 /* Allocate the data area */
4141 new_file_size
= allocation_start
+
4142 nb_new_data_clusters
* s
->cluster_size
;
4143 /* Image file grows, so @exact does not matter */
4144 ret
= bdrv_co_truncate(bs
->file
, new_file_size
, false, prealloc
, errp
);
4146 error_prepend(errp
, "Failed to resize underlying file: ");
4147 qcow2_free_clusters(bs
, allocation_start
,
4148 nb_new_data_clusters
* s
->cluster_size
,
4149 QCOW2_DISCARD_OTHER
);
4153 /* Create the necessary L2 entries */
4154 host_offset
= allocation_start
;
4155 guest_offset
= old_length
;
4156 while (nb_new_data_clusters
) {
4157 int64_t nb_clusters
= MIN(
4158 nb_new_data_clusters
,
4159 s
->l2_slice_size
- offset_to_l2_slice_index(s
, guest_offset
));
4160 QCowL2Meta allocation
= {
4161 .offset
= guest_offset
,
4162 .alloc_offset
= host_offset
,
4163 .nb_clusters
= nb_clusters
,
4165 qemu_co_queue_init(&allocation
.dependent_requests
);
4167 ret
= qcow2_alloc_cluster_link_l2(bs
, &allocation
);
4169 error_setg_errno(errp
, -ret
, "Failed to update L2 tables");
4170 qcow2_free_clusters(bs
, host_offset
,
4171 nb_new_data_clusters
* s
->cluster_size
,
4172 QCOW2_DISCARD_OTHER
);
4176 guest_offset
+= nb_clusters
* s
->cluster_size
;
4177 host_offset
+= nb_clusters
* s
->cluster_size
;
4178 nb_new_data_clusters
-= nb_clusters
;
4184 g_assert_not_reached();
4187 if (prealloc
!= PREALLOC_MODE_OFF
) {
4188 /* Flush metadata before actually changing the image size */
4189 ret
= qcow2_write_caches(bs
);
4191 error_setg_errno(errp
, -ret
,
4192 "Failed to flush the preallocated area to disk");
4197 bs
->total_sectors
= offset
/ BDRV_SECTOR_SIZE
;
4199 /* write updated header.size */
4200 offset
= cpu_to_be64(offset
);
4201 ret
= bdrv_pwrite_sync(bs
->file
, offsetof(QCowHeader
, size
),
4202 &offset
, sizeof(uint64_t));
4204 error_setg_errno(errp
, -ret
, "Failed to update the image size");
4208 s
->l1_vm_state_index
= new_l1_size
;
4210 /* Update cache sizes */
4211 options
= qdict_clone_shallow(bs
->options
);
4212 ret
= qcow2_update_options(bs
, options
, s
->flags
, errp
);
4213 qobject_unref(options
);
4219 qemu_co_mutex_unlock(&s
->lock
);
4223 static coroutine_fn
int
4224 qcow2_co_pwritev_compressed_task(BlockDriverState
*bs
,
4225 uint64_t offset
, uint64_t bytes
,
4226 QEMUIOVector
*qiov
, size_t qiov_offset
)
4228 BDRVQcow2State
*s
= bs
->opaque
;
4231 uint8_t *buf
, *out_buf
;
4232 uint64_t cluster_offset
;
4234 assert(bytes
== s
->cluster_size
|| (bytes
< s
->cluster_size
&&
4235 (offset
+ bytes
== bs
->total_sectors
<< BDRV_SECTOR_BITS
)));
4237 buf
= qemu_blockalign(bs
, s
->cluster_size
);
4238 if (bytes
< s
->cluster_size
) {
4239 /* Zero-pad last write if image size is not cluster aligned */
4240 memset(buf
+ bytes
, 0, s
->cluster_size
- bytes
);
4242 qemu_iovec_to_buf(qiov
, qiov_offset
, buf
, bytes
);
4244 out_buf
= g_malloc(s
->cluster_size
);
4246 out_len
= qcow2_co_compress(bs
, out_buf
, s
->cluster_size
- 1,
4247 buf
, s
->cluster_size
);
4248 if (out_len
== -ENOMEM
) {
4249 /* could not compress: write normal cluster */
4250 ret
= qcow2_co_pwritev_part(bs
, offset
, bytes
, qiov
, qiov_offset
, 0);
4255 } else if (out_len
< 0) {
4260 qemu_co_mutex_lock(&s
->lock
);
4261 ret
= qcow2_alloc_compressed_cluster_offset(bs
, offset
, out_len
,
4264 qemu_co_mutex_unlock(&s
->lock
);
4268 ret
= qcow2_pre_write_overlap_check(bs
, 0, cluster_offset
, out_len
, true);
4269 qemu_co_mutex_unlock(&s
->lock
);
4274 BLKDBG_EVENT(s
->data_file
, BLKDBG_WRITE_COMPRESSED
);
4275 ret
= bdrv_co_pwrite(s
->data_file
, cluster_offset
, out_len
, out_buf
, 0);
4287 static coroutine_fn
int qcow2_co_pwritev_compressed_task_entry(AioTask
*task
)
4289 Qcow2AioTask
*t
= container_of(task
, Qcow2AioTask
, task
);
4291 assert(!t
->cluster_type
&& !t
->l2meta
);
4293 return qcow2_co_pwritev_compressed_task(t
->bs
, t
->offset
, t
->bytes
, t
->qiov
,
4298 * XXX: put compressed sectors first, then all the cluster aligned
4299 * tables to avoid losing bytes in alignment
4301 static coroutine_fn
int
4302 qcow2_co_pwritev_compressed_part(BlockDriverState
*bs
,
4303 uint64_t offset
, uint64_t bytes
,
4304 QEMUIOVector
*qiov
, size_t qiov_offset
)
4306 BDRVQcow2State
*s
= bs
->opaque
;
4307 AioTaskPool
*aio
= NULL
;
4310 if (has_data_file(bs
)) {
4316 * align end of file to a sector boundary to ease reading with
4319 int64_t len
= bdrv_getlength(bs
->file
->bs
);
4323 return bdrv_co_truncate(bs
->file
, len
, false, PREALLOC_MODE_OFF
, NULL
);
4326 if (offset_into_cluster(s
, offset
)) {
4330 while (bytes
&& aio_task_pool_status(aio
) == 0) {
4331 uint64_t chunk_size
= MIN(bytes
, s
->cluster_size
);
4333 if (!aio
&& chunk_size
!= bytes
) {
4334 aio
= aio_task_pool_new(QCOW2_MAX_WORKERS
);
4337 ret
= qcow2_add_task(bs
, aio
, qcow2_co_pwritev_compressed_task_entry
,
4338 0, 0, offset
, chunk_size
, qiov
, qiov_offset
, NULL
);
4342 qiov_offset
+= chunk_size
;
4343 offset
+= chunk_size
;
4344 bytes
-= chunk_size
;
4348 aio_task_pool_wait_all(aio
);
4350 ret
= aio_task_pool_status(aio
);
4358 static int coroutine_fn
4359 qcow2_co_preadv_compressed(BlockDriverState
*bs
,
4360 uint64_t file_cluster_offset
,
4366 BDRVQcow2State
*s
= bs
->opaque
;
4367 int ret
= 0, csize
, nb_csectors
;
4369 uint8_t *buf
, *out_buf
;
4370 int offset_in_cluster
= offset_into_cluster(s
, offset
);
4372 coffset
= file_cluster_offset
& s
->cluster_offset_mask
;
4373 nb_csectors
= ((file_cluster_offset
>> s
->csize_shift
) & s
->csize_mask
) + 1;
4374 csize
= nb_csectors
* QCOW2_COMPRESSED_SECTOR_SIZE
-
4375 (coffset
& ~QCOW2_COMPRESSED_SECTOR_MASK
);
4377 buf
= g_try_malloc(csize
);
4382 out_buf
= qemu_blockalign(bs
, s
->cluster_size
);
4384 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_COMPRESSED
);
4385 ret
= bdrv_co_pread(bs
->file
, coffset
, csize
, buf
, 0);
4390 if (qcow2_co_decompress(bs
, out_buf
, s
->cluster_size
, buf
, csize
) < 0) {
4395 qemu_iovec_from_buf(qiov
, qiov_offset
, out_buf
+ offset_in_cluster
, bytes
);
4398 qemu_vfree(out_buf
);
4404 static int make_completely_empty(BlockDriverState
*bs
)
4406 BDRVQcow2State
*s
= bs
->opaque
;
4407 Error
*local_err
= NULL
;
4408 int ret
, l1_clusters
;
4410 uint64_t *new_reftable
= NULL
;
4411 uint64_t rt_entry
, l1_size2
;
4414 uint64_t reftable_offset
;
4415 uint32_t reftable_clusters
;
4416 } QEMU_PACKED l1_ofs_rt_ofs_cls
;
4418 ret
= qcow2_cache_empty(bs
, s
->l2_table_cache
);
4423 ret
= qcow2_cache_empty(bs
, s
->refcount_block_cache
);
4428 /* Refcounts will be broken utterly */
4429 ret
= qcow2_mark_dirty(bs
);
4434 BLKDBG_EVENT(bs
->file
, BLKDBG_L1_UPDATE
);
4436 l1_clusters
= DIV_ROUND_UP(s
->l1_size
, s
->cluster_size
/ sizeof(uint64_t));
4437 l1_size2
= (uint64_t)s
->l1_size
* sizeof(uint64_t);
4439 /* After this call, neither the in-memory nor the on-disk refcount
4440 * information accurately describe the actual references */
4442 ret
= bdrv_pwrite_zeroes(bs
->file
, s
->l1_table_offset
,
4443 l1_clusters
* s
->cluster_size
, 0);
4445 goto fail_broken_refcounts
;
4447 memset(s
->l1_table
, 0, l1_size2
);
4449 BLKDBG_EVENT(bs
->file
, BLKDBG_EMPTY_IMAGE_PREPARE
);
4451 /* Overwrite enough clusters at the beginning of the sectors to place
4452 * the refcount table, a refcount block and the L1 table in; this may
4453 * overwrite parts of the existing refcount and L1 table, which is not
4454 * an issue because the dirty flag is set, complete data loss is in fact
4455 * desired and partial data loss is consequently fine as well */
4456 ret
= bdrv_pwrite_zeroes(bs
->file
, s
->cluster_size
,
4457 (2 + l1_clusters
) * s
->cluster_size
, 0);
4458 /* This call (even if it failed overall) may have overwritten on-disk
4459 * refcount structures; in that case, the in-memory refcount information
4460 * will probably differ from the on-disk information which makes the BDS
4463 goto fail_broken_refcounts
;
4466 BLKDBG_EVENT(bs
->file
, BLKDBG_L1_UPDATE
);
4467 BLKDBG_EVENT(bs
->file
, BLKDBG_REFTABLE_UPDATE
);
4469 /* "Create" an empty reftable (one cluster) directly after the image
4470 * header and an empty L1 table three clusters after the image header;
4471 * the cluster between those two will be used as the first refblock */
4472 l1_ofs_rt_ofs_cls
.l1_offset
= cpu_to_be64(3 * s
->cluster_size
);
4473 l1_ofs_rt_ofs_cls
.reftable_offset
= cpu_to_be64(s
->cluster_size
);
4474 l1_ofs_rt_ofs_cls
.reftable_clusters
= cpu_to_be32(1);
4475 ret
= bdrv_pwrite_sync(bs
->file
, offsetof(QCowHeader
, l1_table_offset
),
4476 &l1_ofs_rt_ofs_cls
, sizeof(l1_ofs_rt_ofs_cls
));
4478 goto fail_broken_refcounts
;
4481 s
->l1_table_offset
= 3 * s
->cluster_size
;
4483 new_reftable
= g_try_new0(uint64_t, s
->cluster_size
/ sizeof(uint64_t));
4484 if (!new_reftable
) {
4486 goto fail_broken_refcounts
;
4489 s
->refcount_table_offset
= s
->cluster_size
;
4490 s
->refcount_table_size
= s
->cluster_size
/ sizeof(uint64_t);
4491 s
->max_refcount_table_index
= 0;
4493 g_free(s
->refcount_table
);
4494 s
->refcount_table
= new_reftable
;
4495 new_reftable
= NULL
;
4497 /* Now the in-memory refcount information again corresponds to the on-disk
4498 * information (reftable is empty and no refblocks (the refblock cache is
4499 * empty)); however, this means some clusters (e.g. the image header) are
4500 * referenced, but not refcounted, but the normal qcow2 code assumes that
4501 * the in-memory information is always correct */
4503 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_ALLOC
);
4505 /* Enter the first refblock into the reftable */
4506 rt_entry
= cpu_to_be64(2 * s
->cluster_size
);
4507 ret
= bdrv_pwrite_sync(bs
->file
, s
->cluster_size
,
4508 &rt_entry
, sizeof(rt_entry
));
4510 goto fail_broken_refcounts
;
4512 s
->refcount_table
[0] = 2 * s
->cluster_size
;
4514 s
->free_cluster_index
= 0;
4515 assert(3 + l1_clusters
<= s
->refcount_block_size
);
4516 offset
= qcow2_alloc_clusters(bs
, 3 * s
->cluster_size
+ l1_size2
);
4519 goto fail_broken_refcounts
;
4520 } else if (offset
> 0) {
4521 error_report("First cluster in emptied image is in use");
4525 /* Now finally the in-memory information corresponds to the on-disk
4526 * structures and is correct */
4527 ret
= qcow2_mark_clean(bs
);
4532 ret
= bdrv_truncate(bs
->file
, (3 + l1_clusters
) * s
->cluster_size
, false,
4533 PREALLOC_MODE_OFF
, &local_err
);
4535 error_report_err(local_err
);
4541 fail_broken_refcounts
:
4542 /* The BDS is unusable at this point. If we wanted to make it usable, we
4543 * would have to call qcow2_refcount_close(), qcow2_refcount_init(),
4544 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
4545 * again. However, because the functions which could have caused this error
4546 * path to be taken are used by those functions as well, it's very likely
4547 * that that sequence will fail as well. Therefore, just eject the BDS. */
4551 g_free(new_reftable
);
4555 static int qcow2_make_empty(BlockDriverState
*bs
)
4557 BDRVQcow2State
*s
= bs
->opaque
;
4558 uint64_t offset
, end_offset
;
4559 int step
= QEMU_ALIGN_DOWN(INT_MAX
, s
->cluster_size
);
4560 int l1_clusters
, ret
= 0;
4562 l1_clusters
= DIV_ROUND_UP(s
->l1_size
, s
->cluster_size
/ sizeof(uint64_t));
4564 if (s
->qcow_version
>= 3 && !s
->snapshots
&& !s
->nb_bitmaps
&&
4565 3 + l1_clusters
<= s
->refcount_block_size
&&
4566 s
->crypt_method_header
!= QCOW_CRYPT_LUKS
&&
4567 !has_data_file(bs
)) {
4568 /* The following function only works for qcow2 v3 images (it
4569 * requires the dirty flag) and only as long as there are no
4570 * features that reserve extra clusters (such as snapshots,
4571 * LUKS header, or persistent bitmaps), because it completely
4572 * empties the image. Furthermore, the L1 table and three
4573 * additional clusters (image header, refcount table, one
4574 * refcount block) have to fit inside one refcount block. It
4575 * only resets the image file, i.e. does not work with an
4576 * external data file. */
4577 return make_completely_empty(bs
);
4580 /* This fallback code simply discards every active cluster; this is slow,
4581 * but works in all cases */
4582 end_offset
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
4583 for (offset
= 0; offset
< end_offset
; offset
+= step
) {
4584 /* As this function is generally used after committing an external
4585 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
4586 * default action for this kind of discard is to pass the discard,
4587 * which will ideally result in an actually smaller image file, as
4588 * is probably desired. */
4589 ret
= qcow2_cluster_discard(bs
, offset
, MIN(step
, end_offset
- offset
),
4590 QCOW2_DISCARD_SNAPSHOT
, true);
4599 static coroutine_fn
int qcow2_co_flush_to_os(BlockDriverState
*bs
)
4601 BDRVQcow2State
*s
= bs
->opaque
;
4604 qemu_co_mutex_lock(&s
->lock
);
4605 ret
= qcow2_write_caches(bs
);
4606 qemu_co_mutex_unlock(&s
->lock
);
4611 static ssize_t
qcow2_measure_crypto_hdr_init_func(QCryptoBlock
*block
,
4612 size_t headerlen
, void *opaque
, Error
**errp
)
4614 size_t *headerlenp
= opaque
;
4616 /* Stash away the payload size */
4617 *headerlenp
= headerlen
;
4621 static ssize_t
qcow2_measure_crypto_hdr_write_func(QCryptoBlock
*block
,
4622 size_t offset
, const uint8_t *buf
, size_t buflen
,
4623 void *opaque
, Error
**errp
)
4625 /* Discard the bytes, we're not actually writing to an image */
4629 /* Determine the number of bytes for the LUKS payload */
4630 static bool qcow2_measure_luks_headerlen(QemuOpts
*opts
, size_t *len
,
4634 QDict
*cryptoopts_qdict
;
4635 QCryptoBlockCreateOptions
*cryptoopts
;
4636 QCryptoBlock
*crypto
;
4638 /* Extract "encrypt." options into a qdict */
4639 opts_qdict
= qemu_opts_to_qdict(opts
, NULL
);
4640 qdict_extract_subqdict(opts_qdict
, &cryptoopts_qdict
, "encrypt.");
4641 qobject_unref(opts_qdict
);
4643 /* Build QCryptoBlockCreateOptions object from qdict */
4644 qdict_put_str(cryptoopts_qdict
, "format", "luks");
4645 cryptoopts
= block_crypto_create_opts_init(cryptoopts_qdict
, errp
);
4646 qobject_unref(cryptoopts_qdict
);
4651 /* Fake LUKS creation in order to determine the payload size */
4652 crypto
= qcrypto_block_create(cryptoopts
, "encrypt.",
4653 qcow2_measure_crypto_hdr_init_func
,
4654 qcow2_measure_crypto_hdr_write_func
,
4656 qapi_free_QCryptoBlockCreateOptions(cryptoopts
);
4661 qcrypto_block_free(crypto
);
4665 static BlockMeasureInfo
*qcow2_measure(QemuOpts
*opts
, BlockDriverState
*in_bs
,
4668 Error
*local_err
= NULL
;
4669 BlockMeasureInfo
*info
;
4670 uint64_t required
= 0; /* bytes that contribute to required size */
4671 uint64_t virtual_size
; /* disk size as seen by guest */
4672 uint64_t refcount_bits
;
4674 uint64_t luks_payload_size
= 0;
4675 size_t cluster_size
;
4678 PreallocMode prealloc
;
4679 bool has_backing_file
;
4682 /* Parse image creation options */
4683 cluster_size
= qcow2_opt_get_cluster_size_del(opts
, &local_err
);
4688 version
= qcow2_opt_get_version_del(opts
, &local_err
);
4693 refcount_bits
= qcow2_opt_get_refcount_bits_del(opts
, version
, &local_err
);
4698 optstr
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
4699 prealloc
= qapi_enum_parse(&PreallocMode_lookup
, optstr
,
4700 PREALLOC_MODE_OFF
, &local_err
);
4706 optstr
= qemu_opt_get_del(opts
, BLOCK_OPT_BACKING_FILE
);
4707 has_backing_file
= !!optstr
;
4710 optstr
= qemu_opt_get_del(opts
, BLOCK_OPT_ENCRYPT_FORMAT
);
4711 has_luks
= optstr
&& strcmp(optstr
, "luks") == 0;
4717 if (!qcow2_measure_luks_headerlen(opts
, &headerlen
, &local_err
)) {
4721 luks_payload_size
= ROUND_UP(headerlen
, cluster_size
);
4724 virtual_size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0);
4725 virtual_size
= ROUND_UP(virtual_size
, cluster_size
);
4727 /* Check that virtual disk size is valid */
4728 l2_tables
= DIV_ROUND_UP(virtual_size
/ cluster_size
,
4729 cluster_size
/ sizeof(uint64_t));
4730 if (l2_tables
* sizeof(uint64_t) > QCOW_MAX_L1_SIZE
) {
4731 error_setg(&local_err
, "The image size is too large "
4732 "(try using a larger cluster size)");
4736 /* Account for input image */
4738 int64_t ssize
= bdrv_getlength(in_bs
);
4740 error_setg_errno(&local_err
, -ssize
,
4741 "Unable to get image virtual_size");
4745 virtual_size
= ROUND_UP(ssize
, cluster_size
);
4747 if (has_backing_file
) {
4748 /* We don't how much of the backing chain is shared by the input
4749 * image and the new image file. In the worst case the new image's
4750 * backing file has nothing in common with the input image. Be
4751 * conservative and assume all clusters need to be written.
4753 required
= virtual_size
;
4758 for (offset
= 0; offset
< ssize
; offset
+= pnum
) {
4761 ret
= bdrv_block_status_above(in_bs
, NULL
, offset
,
4762 ssize
- offset
, &pnum
, NULL
,
4765 error_setg_errno(&local_err
, -ret
,
4766 "Unable to get block status");
4770 if (ret
& BDRV_BLOCK_ZERO
) {
4771 /* Skip zero regions (safe with no backing file) */
4772 } else if ((ret
& (BDRV_BLOCK_DATA
| BDRV_BLOCK_ALLOCATED
)) ==
4773 (BDRV_BLOCK_DATA
| BDRV_BLOCK_ALLOCATED
)) {
4774 /* Extend pnum to end of cluster for next iteration */
4775 pnum
= ROUND_UP(offset
+ pnum
, cluster_size
) - offset
;
4777 /* Count clusters we've seen */
4778 required
+= offset
% cluster_size
+ pnum
;
4784 /* Take into account preallocation. Nothing special is needed for
4785 * PREALLOC_MODE_METADATA since metadata is always counted.
4787 if (prealloc
== PREALLOC_MODE_FULL
|| prealloc
== PREALLOC_MODE_FALLOC
) {
4788 required
= virtual_size
;
4791 info
= g_new(BlockMeasureInfo
, 1);
4792 info
->fully_allocated
=
4793 qcow2_calc_prealloc_size(virtual_size
, cluster_size
,
4794 ctz32(refcount_bits
)) + luks_payload_size
;
4796 /* Remove data clusters that are not required. This overestimates the
4797 * required size because metadata needed for the fully allocated file is
4800 info
->required
= info
->fully_allocated
- virtual_size
+ required
;
4804 error_propagate(errp
, local_err
);
4808 static int qcow2_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
4810 BDRVQcow2State
*s
= bs
->opaque
;
4811 bdi
->unallocated_blocks_are_zero
= true;
4812 bdi
->cluster_size
= s
->cluster_size
;
4813 bdi
->vm_state_offset
= qcow2_vm_state_offset(s
);
4817 static ImageInfoSpecific
*qcow2_get_specific_info(BlockDriverState
*bs
,
4820 BDRVQcow2State
*s
= bs
->opaque
;
4821 ImageInfoSpecific
*spec_info
;
4822 QCryptoBlockInfo
*encrypt_info
= NULL
;
4823 Error
*local_err
= NULL
;
4825 if (s
->crypto
!= NULL
) {
4826 encrypt_info
= qcrypto_block_get_info(s
->crypto
, &local_err
);
4828 error_propagate(errp
, local_err
);
4833 spec_info
= g_new(ImageInfoSpecific
, 1);
4834 *spec_info
= (ImageInfoSpecific
){
4835 .type
= IMAGE_INFO_SPECIFIC_KIND_QCOW2
,
4836 .u
.qcow2
.data
= g_new0(ImageInfoSpecificQCow2
, 1),
4838 if (s
->qcow_version
== 2) {
4839 *spec_info
->u
.qcow2
.data
= (ImageInfoSpecificQCow2
){
4840 .compat
= g_strdup("0.10"),
4841 .refcount_bits
= s
->refcount_bits
,
4843 } else if (s
->qcow_version
== 3) {
4844 Qcow2BitmapInfoList
*bitmaps
;
4845 bitmaps
= qcow2_get_bitmap_info_list(bs
, &local_err
);
4847 error_propagate(errp
, local_err
);
4848 qapi_free_ImageInfoSpecific(spec_info
);
4851 *spec_info
->u
.qcow2
.data
= (ImageInfoSpecificQCow2
){
4852 .compat
= g_strdup("1.1"),
4853 .lazy_refcounts
= s
->compatible_features
&
4854 QCOW2_COMPAT_LAZY_REFCOUNTS
,
4855 .has_lazy_refcounts
= true,
4856 .corrupt
= s
->incompatible_features
&
4857 QCOW2_INCOMPAT_CORRUPT
,
4858 .has_corrupt
= true,
4859 .refcount_bits
= s
->refcount_bits
,
4860 .has_bitmaps
= !!bitmaps
,
4862 .has_data_file
= !!s
->image_data_file
,
4863 .data_file
= g_strdup(s
->image_data_file
),
4864 .has_data_file_raw
= has_data_file(bs
),
4865 .data_file_raw
= data_file_is_raw(bs
),
4868 /* if this assertion fails, this probably means a new version was
4869 * added without having it covered here */
4874 ImageInfoSpecificQCow2Encryption
*qencrypt
=
4875 g_new(ImageInfoSpecificQCow2Encryption
, 1);
4876 switch (encrypt_info
->format
) {
4877 case Q_CRYPTO_BLOCK_FORMAT_QCOW
:
4878 qencrypt
->format
= BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES
;
4880 case Q_CRYPTO_BLOCK_FORMAT_LUKS
:
4881 qencrypt
->format
= BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS
;
4882 qencrypt
->u
.luks
= encrypt_info
->u
.luks
;
4887 /* Since we did shallow copy above, erase any pointers
4888 * in the original info */
4889 memset(&encrypt_info
->u
, 0, sizeof(encrypt_info
->u
));
4890 qapi_free_QCryptoBlockInfo(encrypt_info
);
4892 spec_info
->u
.qcow2
.data
->has_encrypt
= true;
4893 spec_info
->u
.qcow2
.data
->encrypt
= qencrypt
;
4899 static int qcow2_has_zero_init(BlockDriverState
*bs
)
4901 BDRVQcow2State
*s
= bs
->opaque
;
4904 if (qemu_in_coroutine()) {
4905 qemu_co_mutex_lock(&s
->lock
);
4908 * Check preallocation status: Preallocated images have all L2
4909 * tables allocated, nonpreallocated images have none. It is
4910 * therefore enough to check the first one.
4912 preallocated
= s
->l1_size
> 0 && s
->l1_table
[0] != 0;
4913 if (qemu_in_coroutine()) {
4914 qemu_co_mutex_unlock(&s
->lock
);
4917 if (!preallocated
) {
4919 } else if (bs
->encrypted
) {
4922 return bdrv_has_zero_init(s
->data_file
->bs
);
4926 static int qcow2_save_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
4929 BDRVQcow2State
*s
= bs
->opaque
;
4931 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_SAVE
);
4932 return bs
->drv
->bdrv_co_pwritev_part(bs
, qcow2_vm_state_offset(s
) + pos
,
4933 qiov
->size
, qiov
, 0, 0);
4936 static int qcow2_load_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
4939 BDRVQcow2State
*s
= bs
->opaque
;
4941 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_LOAD
);
4942 return bs
->drv
->bdrv_co_preadv_part(bs
, qcow2_vm_state_offset(s
) + pos
,
4943 qiov
->size
, qiov
, 0, 0);
4947 * Downgrades an image's version. To achieve this, any incompatible features
4948 * have to be removed.
4950 static int qcow2_downgrade(BlockDriverState
*bs
, int target_version
,
4951 BlockDriverAmendStatusCB
*status_cb
, void *cb_opaque
,
4954 BDRVQcow2State
*s
= bs
->opaque
;
4955 int current_version
= s
->qcow_version
;
4958 /* This is qcow2_downgrade(), not qcow2_upgrade() */
4959 assert(target_version
< current_version
);
4961 /* There are no other versions (now) that you can downgrade to */
4962 assert(target_version
== 2);
4964 if (s
->refcount_order
!= 4) {
4965 error_setg(errp
, "compat=0.10 requires refcount_bits=16");
4969 if (has_data_file(bs
)) {
4970 error_setg(errp
, "Cannot downgrade an image with a data file");
4974 /* clear incompatible features */
4975 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
4976 ret
= qcow2_mark_clean(bs
);
4978 error_setg_errno(errp
, -ret
, "Failed to make the image clean");
4983 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
4984 * the first place; if that happens nonetheless, returning -ENOTSUP is the
4985 * best thing to do anyway */
4987 if (s
->incompatible_features
) {
4988 error_setg(errp
, "Cannot downgrade an image with incompatible features "
4989 "%#" PRIx64
" set", s
->incompatible_features
);
4993 /* since we can ignore compatible features, we can set them to 0 as well */
4994 s
->compatible_features
= 0;
4995 /* if lazy refcounts have been used, they have already been fixed through
4996 * clearing the dirty flag */
4998 /* clearing autoclear features is trivial */
4999 s
->autoclear_features
= 0;
5001 ret
= qcow2_expand_zero_clusters(bs
, status_cb
, cb_opaque
);
5003 error_setg_errno(errp
, -ret
, "Failed to turn zero into data clusters");
5007 s
->qcow_version
= target_version
;
5008 ret
= qcow2_update_header(bs
);
5010 s
->qcow_version
= current_version
;
5011 error_setg_errno(errp
, -ret
, "Failed to update the image header");
5018 * Upgrades an image's version. While newer versions encompass all
5019 * features of older versions, some things may have to be presented
5022 static int qcow2_upgrade(BlockDriverState
*bs
, int target_version
,
5023 BlockDriverAmendStatusCB
*status_cb
, void *cb_opaque
,
5026 BDRVQcow2State
*s
= bs
->opaque
;
5027 bool need_snapshot_update
;
5028 int current_version
= s
->qcow_version
;
5032 /* This is qcow2_upgrade(), not qcow2_downgrade() */
5033 assert(target_version
> current_version
);
5035 /* There are no other versions (yet) that you can upgrade to */
5036 assert(target_version
== 3);
5038 status_cb(bs
, 0, 2, cb_opaque
);
5041 * In v2, snapshots do not need to have extra data. v3 requires
5042 * the 64-bit VM state size and the virtual disk size to be
5044 * qcow2_write_snapshots() will always write the list in the
5045 * v3-compliant format.
5047 need_snapshot_update
= false;
5048 for (i
= 0; i
< s
->nb_snapshots
; i
++) {
5049 if (s
->snapshots
[i
].extra_data_size
<
5050 sizeof_field(QCowSnapshotExtraData
, vm_state_size_large
) +
5051 sizeof_field(QCowSnapshotExtraData
, disk_size
))
5053 need_snapshot_update
= true;
5057 if (need_snapshot_update
) {
5058 ret
= qcow2_write_snapshots(bs
);
5060 error_setg_errno(errp
, -ret
, "Failed to update the snapshot table");
5064 status_cb(bs
, 1, 2, cb_opaque
);
5066 s
->qcow_version
= target_version
;
5067 ret
= qcow2_update_header(bs
);
5069 s
->qcow_version
= current_version
;
5070 error_setg_errno(errp
, -ret
, "Failed to update the image header");
5073 status_cb(bs
, 2, 2, cb_opaque
);
5078 typedef enum Qcow2AmendOperation
{
5079 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be
5080 * statically initialized to so that the helper CB can discern the first
5081 * invocation from an operation change */
5082 QCOW2_NO_OPERATION
= 0,
5085 QCOW2_CHANGING_REFCOUNT_ORDER
,
5087 } Qcow2AmendOperation
;
5089 typedef struct Qcow2AmendHelperCBInfo
{
5090 /* The code coordinating the amend operations should only modify
5091 * these four fields; the rest will be managed by the CB */
5092 BlockDriverAmendStatusCB
*original_status_cb
;
5093 void *original_cb_opaque
;
5095 Qcow2AmendOperation current_operation
;
5097 /* Total number of operations to perform (only set once) */
5098 int total_operations
;
5100 /* The following fields are managed by the CB */
5102 /* Number of operations completed */
5103 int operations_completed
;
5105 /* Cumulative offset of all completed operations */
5106 int64_t offset_completed
;
5108 Qcow2AmendOperation last_operation
;
5109 int64_t last_work_size
;
5110 } Qcow2AmendHelperCBInfo
;
5112 static void qcow2_amend_helper_cb(BlockDriverState
*bs
,
5113 int64_t operation_offset
,
5114 int64_t operation_work_size
, void *opaque
)
5116 Qcow2AmendHelperCBInfo
*info
= opaque
;
5117 int64_t current_work_size
;
5118 int64_t projected_work_size
;
5120 if (info
->current_operation
!= info
->last_operation
) {
5121 if (info
->last_operation
!= QCOW2_NO_OPERATION
) {
5122 info
->offset_completed
+= info
->last_work_size
;
5123 info
->operations_completed
++;
5126 info
->last_operation
= info
->current_operation
;
5129 assert(info
->total_operations
> 0);
5130 assert(info
->operations_completed
< info
->total_operations
);
5132 info
->last_work_size
= operation_work_size
;
5134 current_work_size
= info
->offset_completed
+ operation_work_size
;
5136 /* current_work_size is the total work size for (operations_completed + 1)
5137 * operations (which includes this one), so multiply it by the number of
5138 * operations not covered and divide it by the number of operations
5139 * covered to get a projection for the operations not covered */
5140 projected_work_size
= current_work_size
* (info
->total_operations
-
5141 info
->operations_completed
- 1)
5142 / (info
->operations_completed
+ 1);
5144 info
->original_status_cb(bs
, info
->offset_completed
+ operation_offset
,
5145 current_work_size
+ projected_work_size
,
5146 info
->original_cb_opaque
);
5149 static int qcow2_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
,
5150 BlockDriverAmendStatusCB
*status_cb
,
5154 BDRVQcow2State
*s
= bs
->opaque
;
5155 int old_version
= s
->qcow_version
, new_version
= old_version
;
5156 uint64_t new_size
= 0;
5157 const char *backing_file
= NULL
, *backing_format
= NULL
, *data_file
= NULL
;
5158 bool lazy_refcounts
= s
->use_lazy_refcounts
;
5159 bool data_file_raw
= data_file_is_raw(bs
);
5160 const char *compat
= NULL
;
5161 uint64_t cluster_size
= s
->cluster_size
;
5164 int refcount_bits
= s
->refcount_bits
;
5166 QemuOptDesc
*desc
= opts
->list
->desc
;
5167 Qcow2AmendHelperCBInfo helper_cb_info
;
5169 while (desc
&& desc
->name
) {
5170 if (!qemu_opt_find(opts
, desc
->name
)) {
5171 /* only change explicitly defined options */
5176 if (!strcmp(desc
->name
, BLOCK_OPT_COMPAT_LEVEL
)) {
5177 compat
= qemu_opt_get(opts
, BLOCK_OPT_COMPAT_LEVEL
);
5179 /* preserve default */
5180 } else if (!strcmp(compat
, "0.10") || !strcmp(compat
, "v2")) {
5182 } else if (!strcmp(compat
, "1.1") || !strcmp(compat
, "v3")) {
5185 error_setg(errp
, "Unknown compatibility level %s", compat
);
5188 } else if (!strcmp(desc
->name
, BLOCK_OPT_PREALLOC
)) {
5189 error_setg(errp
, "Cannot change preallocation mode");
5191 } else if (!strcmp(desc
->name
, BLOCK_OPT_SIZE
)) {
5192 new_size
= qemu_opt_get_size(opts
, BLOCK_OPT_SIZE
, 0);
5193 } else if (!strcmp(desc
->name
, BLOCK_OPT_BACKING_FILE
)) {
5194 backing_file
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FILE
);
5195 } else if (!strcmp(desc
->name
, BLOCK_OPT_BACKING_FMT
)) {
5196 backing_format
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FMT
);
5197 } else if (!strcmp(desc
->name
, BLOCK_OPT_ENCRYPT
)) {
5198 encrypt
= qemu_opt_get_bool(opts
, BLOCK_OPT_ENCRYPT
,
5201 if (encrypt
!= !!s
->crypto
) {
5203 "Changing the encryption flag is not supported");
5206 } else if (!strcmp(desc
->name
, BLOCK_OPT_ENCRYPT_FORMAT
)) {
5207 encformat
= qcow2_crypt_method_from_format(
5208 qemu_opt_get(opts
, BLOCK_OPT_ENCRYPT_FORMAT
));
5210 if (encformat
!= s
->crypt_method_header
) {
5212 "Changing the encryption format is not supported");
5215 } else if (g_str_has_prefix(desc
->name
, "encrypt.")) {
5217 "Changing the encryption parameters is not supported");
5219 } else if (!strcmp(desc
->name
, BLOCK_OPT_CLUSTER_SIZE
)) {
5220 cluster_size
= qemu_opt_get_size(opts
, BLOCK_OPT_CLUSTER_SIZE
,
5222 if (cluster_size
!= s
->cluster_size
) {
5223 error_setg(errp
, "Changing the cluster size is not supported");
5226 } else if (!strcmp(desc
->name
, BLOCK_OPT_LAZY_REFCOUNTS
)) {
5227 lazy_refcounts
= qemu_opt_get_bool(opts
, BLOCK_OPT_LAZY_REFCOUNTS
,
5229 } else if (!strcmp(desc
->name
, BLOCK_OPT_REFCOUNT_BITS
)) {
5230 refcount_bits
= qemu_opt_get_number(opts
, BLOCK_OPT_REFCOUNT_BITS
,
5233 if (refcount_bits
<= 0 || refcount_bits
> 64 ||
5234 !is_power_of_2(refcount_bits
))
5236 error_setg(errp
, "Refcount width must be a power of two and "
5237 "may not exceed 64 bits");
5240 } else if (!strcmp(desc
->name
, BLOCK_OPT_DATA_FILE
)) {
5241 data_file
= qemu_opt_get(opts
, BLOCK_OPT_DATA_FILE
);
5242 if (data_file
&& !has_data_file(bs
)) {
5243 error_setg(errp
, "data-file can only be set for images that "
5244 "use an external data file");
5247 } else if (!strcmp(desc
->name
, BLOCK_OPT_DATA_FILE_RAW
)) {
5248 data_file_raw
= qemu_opt_get_bool(opts
, BLOCK_OPT_DATA_FILE_RAW
,
5250 if (data_file_raw
&& !data_file_is_raw(bs
)) {
5251 error_setg(errp
, "data-file-raw cannot be set on existing "
5256 /* if this point is reached, this probably means a new option was
5257 * added without having it covered here */
5264 helper_cb_info
= (Qcow2AmendHelperCBInfo
){
5265 .original_status_cb
= status_cb
,
5266 .original_cb_opaque
= cb_opaque
,
5267 .total_operations
= (new_version
!= old_version
)
5268 + (s
->refcount_bits
!= refcount_bits
)
5271 /* Upgrade first (some features may require compat=1.1) */
5272 if (new_version
> old_version
) {
5273 helper_cb_info
.current_operation
= QCOW2_UPGRADING
;
5274 ret
= qcow2_upgrade(bs
, new_version
, &qcow2_amend_helper_cb
,
5275 &helper_cb_info
, errp
);
5281 if (s
->refcount_bits
!= refcount_bits
) {
5282 int refcount_order
= ctz32(refcount_bits
);
5284 if (new_version
< 3 && refcount_bits
!= 16) {
5285 error_setg(errp
, "Refcount widths other than 16 bits require "
5286 "compatibility level 1.1 or above (use compat=1.1 or "
5291 helper_cb_info
.current_operation
= QCOW2_CHANGING_REFCOUNT_ORDER
;
5292 ret
= qcow2_change_refcount_order(bs
, refcount_order
,
5293 &qcow2_amend_helper_cb
,
5294 &helper_cb_info
, errp
);
5300 /* data-file-raw blocks backing files, so clear it first if requested */
5301 if (data_file_raw
) {
5302 s
->autoclear_features
|= QCOW2_AUTOCLEAR_DATA_FILE_RAW
;
5304 s
->autoclear_features
&= ~QCOW2_AUTOCLEAR_DATA_FILE_RAW
;
5308 g_free(s
->image_data_file
);
5309 s
->image_data_file
= *data_file
? g_strdup(data_file
) : NULL
;
5312 ret
= qcow2_update_header(bs
);
5314 error_setg_errno(errp
, -ret
, "Failed to update the image header");
5318 if (backing_file
|| backing_format
) {
5319 ret
= qcow2_change_backing_file(bs
,
5320 backing_file
?: s
->image_backing_file
,
5321 backing_format
?: s
->image_backing_format
);
5323 error_setg_errno(errp
, -ret
, "Failed to change the backing file");
5328 if (s
->use_lazy_refcounts
!= lazy_refcounts
) {
5329 if (lazy_refcounts
) {
5330 if (new_version
< 3) {
5331 error_setg(errp
, "Lazy refcounts only supported with "
5332 "compatibility level 1.1 and above (use compat=1.1 "
5336 s
->compatible_features
|= QCOW2_COMPAT_LAZY_REFCOUNTS
;
5337 ret
= qcow2_update_header(bs
);
5339 s
->compatible_features
&= ~QCOW2_COMPAT_LAZY_REFCOUNTS
;
5340 error_setg_errno(errp
, -ret
, "Failed to update the image header");
5343 s
->use_lazy_refcounts
= true;
5345 /* make image clean first */
5346 ret
= qcow2_mark_clean(bs
);
5348 error_setg_errno(errp
, -ret
, "Failed to make the image clean");
5351 /* now disallow lazy refcounts */
5352 s
->compatible_features
&= ~QCOW2_COMPAT_LAZY_REFCOUNTS
;
5353 ret
= qcow2_update_header(bs
);
5355 s
->compatible_features
|= QCOW2_COMPAT_LAZY_REFCOUNTS
;
5356 error_setg_errno(errp
, -ret
, "Failed to update the image header");
5359 s
->use_lazy_refcounts
= false;
5364 BlockBackend
*blk
= blk_new(bdrv_get_aio_context(bs
),
5365 BLK_PERM_RESIZE
, BLK_PERM_ALL
);
5366 ret
= blk_insert_bs(blk
, bs
, errp
);
5373 * Amending image options should ensure that the image has
5374 * exactly the given new values, so pass exact=true here.
5376 ret
= blk_truncate(blk
, new_size
, true, PREALLOC_MODE_OFF
, errp
);
5383 /* Downgrade last (so unsupported features can be removed before) */
5384 if (new_version
< old_version
) {
5385 helper_cb_info
.current_operation
= QCOW2_DOWNGRADING
;
5386 ret
= qcow2_downgrade(bs
, new_version
, &qcow2_amend_helper_cb
,
5387 &helper_cb_info
, errp
);
5397 * If offset or size are negative, respectively, they will not be included in
5398 * the BLOCK_IMAGE_CORRUPTED event emitted.
5399 * fatal will be ignored for read-only BDS; corruptions found there will always
5400 * be considered non-fatal.
5402 void qcow2_signal_corruption(BlockDriverState
*bs
, bool fatal
, int64_t offset
,
5403 int64_t size
, const char *message_format
, ...)
5405 BDRVQcow2State
*s
= bs
->opaque
;
5406 const char *node_name
;
5410 fatal
= fatal
&& bdrv_is_writable(bs
);
5412 if (s
->signaled_corruption
&&
5413 (!fatal
|| (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
)))
5418 va_start(ap
, message_format
);
5419 message
= g_strdup_vprintf(message_format
, ap
);
5423 fprintf(stderr
, "qcow2: Marking image as corrupt: %s; further "
5424 "corruption events will be suppressed\n", message
);
5426 fprintf(stderr
, "qcow2: Image is corrupt: %s; further non-fatal "
5427 "corruption events will be suppressed\n", message
);
5430 node_name
= bdrv_get_node_name(bs
);
5431 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs
),
5432 *node_name
!= '\0', node_name
,
5433 message
, offset
>= 0, offset
,
5439 qcow2_mark_corrupt(bs
);
5440 bs
->drv
= NULL
; /* make BDS unusable */
5443 s
->signaled_corruption
= true;
5446 static QemuOptsList qcow2_create_opts
= {
5447 .name
= "qcow2-create-opts",
5448 .head
= QTAILQ_HEAD_INITIALIZER(qcow2_create_opts
.head
),
5451 .name
= BLOCK_OPT_SIZE
,
5452 .type
= QEMU_OPT_SIZE
,
5453 .help
= "Virtual disk size"
5456 .name
= BLOCK_OPT_COMPAT_LEVEL
,
5457 .type
= QEMU_OPT_STRING
,
5458 .help
= "Compatibility level (v2 [0.10] or v3 [1.1])"
5461 .name
= BLOCK_OPT_BACKING_FILE
,
5462 .type
= QEMU_OPT_STRING
,
5463 .help
= "File name of a base image"
5466 .name
= BLOCK_OPT_BACKING_FMT
,
5467 .type
= QEMU_OPT_STRING
,
5468 .help
= "Image format of the base image"
5471 .name
= BLOCK_OPT_DATA_FILE
,
5472 .type
= QEMU_OPT_STRING
,
5473 .help
= "File name of an external data file"
5476 .name
= BLOCK_OPT_DATA_FILE_RAW
,
5477 .type
= QEMU_OPT_BOOL
,
5478 .help
= "The external data file must stay valid as a raw image"
5481 .name
= BLOCK_OPT_ENCRYPT
,
5482 .type
= QEMU_OPT_BOOL
,
5483 .help
= "Encrypt the image with format 'aes'. (Deprecated "
5484 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT
"=aes)",
5487 .name
= BLOCK_OPT_ENCRYPT_FORMAT
,
5488 .type
= QEMU_OPT_STRING
,
5489 .help
= "Encrypt the image, format choices: 'aes', 'luks'",
5491 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.",
5492 "ID of secret providing qcow AES key or LUKS passphrase"),
5493 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."),
5494 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."),
5495 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."),
5496 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."),
5497 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."),
5498 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."),
5500 .name
= BLOCK_OPT_CLUSTER_SIZE
,
5501 .type
= QEMU_OPT_SIZE
,
5502 .help
= "qcow2 cluster size",
5503 .def_value_str
= stringify(DEFAULT_CLUSTER_SIZE
)
5506 .name
= BLOCK_OPT_PREALLOC
,
5507 .type
= QEMU_OPT_STRING
,
5508 .help
= "Preallocation mode (allowed values: off, metadata, "
5512 .name
= BLOCK_OPT_LAZY_REFCOUNTS
,
5513 .type
= QEMU_OPT_BOOL
,
5514 .help
= "Postpone refcount updates",
5515 .def_value_str
= "off"
5518 .name
= BLOCK_OPT_REFCOUNT_BITS
,
5519 .type
= QEMU_OPT_NUMBER
,
5520 .help
= "Width of a reference count entry in bits",
5521 .def_value_str
= "16"
5523 { /* end of list */ }
5527 static const char *const qcow2_strong_runtime_opts
[] = {
5528 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET
,
5533 BlockDriver bdrv_qcow2
= {
5534 .format_name
= "qcow2",
5535 .instance_size
= sizeof(BDRVQcow2State
),
5536 .bdrv_probe
= qcow2_probe
,
5537 .bdrv_open
= qcow2_open
,
5538 .bdrv_close
= qcow2_close
,
5539 .bdrv_reopen_prepare
= qcow2_reopen_prepare
,
5540 .bdrv_reopen_commit
= qcow2_reopen_commit
,
5541 .bdrv_reopen_commit_post
= qcow2_reopen_commit_post
,
5542 .bdrv_reopen_abort
= qcow2_reopen_abort
,
5543 .bdrv_join_options
= qcow2_join_options
,
5544 .bdrv_child_perm
= bdrv_format_default_perms
,
5545 .bdrv_co_create_opts
= qcow2_co_create_opts
,
5546 .bdrv_co_create
= qcow2_co_create
,
5547 .bdrv_has_zero_init
= qcow2_has_zero_init
,
5548 .bdrv_has_zero_init_truncate
= bdrv_has_zero_init_1
,
5549 .bdrv_co_block_status
= qcow2_co_block_status
,
5551 .bdrv_co_preadv_part
= qcow2_co_preadv_part
,
5552 .bdrv_co_pwritev_part
= qcow2_co_pwritev_part
,
5553 .bdrv_co_flush_to_os
= qcow2_co_flush_to_os
,
5555 .bdrv_co_pwrite_zeroes
= qcow2_co_pwrite_zeroes
,
5556 .bdrv_co_pdiscard
= qcow2_co_pdiscard
,
5557 .bdrv_co_copy_range_from
= qcow2_co_copy_range_from
,
5558 .bdrv_co_copy_range_to
= qcow2_co_copy_range_to
,
5559 .bdrv_co_truncate
= qcow2_co_truncate
,
5560 .bdrv_co_pwritev_compressed_part
= qcow2_co_pwritev_compressed_part
,
5561 .bdrv_make_empty
= qcow2_make_empty
,
5563 .bdrv_snapshot_create
= qcow2_snapshot_create
,
5564 .bdrv_snapshot_goto
= qcow2_snapshot_goto
,
5565 .bdrv_snapshot_delete
= qcow2_snapshot_delete
,
5566 .bdrv_snapshot_list
= qcow2_snapshot_list
,
5567 .bdrv_snapshot_load_tmp
= qcow2_snapshot_load_tmp
,
5568 .bdrv_measure
= qcow2_measure
,
5569 .bdrv_get_info
= qcow2_get_info
,
5570 .bdrv_get_specific_info
= qcow2_get_specific_info
,
5572 .bdrv_save_vmstate
= qcow2_save_vmstate
,
5573 .bdrv_load_vmstate
= qcow2_load_vmstate
,
5575 .supports_backing
= true,
5576 .bdrv_change_backing_file
= qcow2_change_backing_file
,
5578 .bdrv_refresh_limits
= qcow2_refresh_limits
,
5579 .bdrv_co_invalidate_cache
= qcow2_co_invalidate_cache
,
5580 .bdrv_inactivate
= qcow2_inactivate
,
5582 .create_opts
= &qcow2_create_opts
,
5583 .strong_runtime_opts
= qcow2_strong_runtime_opts
,
5584 .mutable_opts
= mutable_opts
,
5585 .bdrv_co_check
= qcow2_co_check
,
5586 .bdrv_amend_options
= qcow2_amend_options
,
5588 .bdrv_detach_aio_context
= qcow2_detach_aio_context
,
5589 .bdrv_attach_aio_context
= qcow2_attach_aio_context
,
5591 .bdrv_co_can_store_new_dirty_bitmap
= qcow2_co_can_store_new_dirty_bitmap
,
5592 .bdrv_co_remove_persistent_dirty_bitmap
=
5593 qcow2_co_remove_persistent_dirty_bitmap
,
5596 static void bdrv_qcow2_init(void)
5598 bdrv_register(&bdrv_qcow2
);
5601 block_init(bdrv_qcow2_init
);