2 * Block driver for the QCOW version 2 format
4 * Copyright (c) 2004-2006 Fabrice Bellard
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 #include "qemu-common.h"
25 #include "block/block_int.h"
26 #include "qemu/module.h"
28 #include "block/qcow2.h"
29 #include "qemu/error-report.h"
30 #include "qapi/qmp/qerror.h"
31 #include "qapi/qmp/qbool.h"
32 #include "qapi/util.h"
33 #include "qapi/qmp/types.h"
34 #include "qapi-event.h"
36 #include "qemu/option_int.h"
39 Differences with QCOW:
41 - Support for multiple incremental snapshots.
42 - Memory management by reference counts.
43 - Clusters which have a reference count of one have the bit
44 QCOW_OFLAG_COPIED to optimize write performance.
45 - Size of compressed clusters is stored in sectors to reduce bit usage
46 in the cluster offsets.
47 - Support for storing additional data (such as the VM state) in the
49 - If a backing store is used, the cluster size is not constrained
50 (could be backported to QCOW).
51 - L2 tables have always a size of one cluster.
58 } QEMU_PACKED QCowExtension
;
60 #define QCOW2_EXT_MAGIC_END 0
61 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
62 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
64 static int qcow2_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
66 const QCowHeader
*cow_header
= (const void *)buf
;
68 if (buf_size
>= sizeof(QCowHeader
) &&
69 be32_to_cpu(cow_header
->magic
) == QCOW_MAGIC
&&
70 be32_to_cpu(cow_header
->version
) >= 2)
78 * read qcow2 extension and fill bs
79 * start reading from start_offset
80 * finish reading upon magic of value 0 or when end_offset reached
81 * unknown magic is skipped (future extension this version knows nothing about)
82 * return 0 upon success, non-0 otherwise
84 static int qcow2_read_extensions(BlockDriverState
*bs
, uint64_t start_offset
,
85 uint64_t end_offset
, void **p_feature_table
,
88 BDRVQcowState
*s
= bs
->opaque
;
94 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset
, end_offset
);
96 offset
= start_offset
;
97 while (offset
< end_offset
) {
101 if (offset
> s
->cluster_size
)
102 printf("qcow2_read_extension: suspicious offset %lu\n", offset
);
104 printf("attempting to read extended header in offset %lu\n", offset
);
107 ret
= bdrv_pread(bs
->file
, offset
, &ext
, sizeof(ext
));
109 error_setg_errno(errp
, -ret
, "qcow2_read_extension: ERROR: "
110 "pread fail from offset %" PRIu64
, offset
);
113 be32_to_cpus(&ext
.magic
);
114 be32_to_cpus(&ext
.len
);
115 offset
+= sizeof(ext
);
117 printf("ext.magic = 0x%x\n", ext
.magic
);
119 if (offset
> end_offset
|| ext
.len
> end_offset
- offset
) {
120 error_setg(errp
, "Header extension too large");
125 case QCOW2_EXT_MAGIC_END
:
128 case QCOW2_EXT_MAGIC_BACKING_FORMAT
:
129 if (ext
.len
>= sizeof(bs
->backing_format
)) {
130 error_setg(errp
, "ERROR: ext_backing_format: len=%" PRIu32
131 " too large (>=%zu)", ext
.len
,
132 sizeof(bs
->backing_format
));
135 ret
= bdrv_pread(bs
->file
, offset
, bs
->backing_format
, ext
.len
);
137 error_setg_errno(errp
, -ret
, "ERROR: ext_backing_format: "
138 "Could not read format name");
141 bs
->backing_format
[ext
.len
] = '\0';
142 s
->image_backing_format
= g_strdup(bs
->backing_format
);
144 printf("Qcow2: Got format extension %s\n", bs
->backing_format
);
148 case QCOW2_EXT_MAGIC_FEATURE_TABLE
:
149 if (p_feature_table
!= NULL
) {
150 void* feature_table
= g_malloc0(ext
.len
+ 2 * sizeof(Qcow2Feature
));
151 ret
= bdrv_pread(bs
->file
, offset
, feature_table
, ext
.len
);
153 error_setg_errno(errp
, -ret
, "ERROR: ext_feature_table: "
154 "Could not read table");
158 *p_feature_table
= feature_table
;
163 /* unknown magic - save it in case we need to rewrite the header */
165 Qcow2UnknownHeaderExtension
*uext
;
167 uext
= g_malloc0(sizeof(*uext
) + ext
.len
);
168 uext
->magic
= ext
.magic
;
170 QLIST_INSERT_HEAD(&s
->unknown_header_ext
, uext
, next
);
172 ret
= bdrv_pread(bs
->file
, offset
, uext
->data
, uext
->len
);
174 error_setg_errno(errp
, -ret
, "ERROR: unknown extension: "
175 "Could not read data");
182 offset
+= ((ext
.len
+ 7) & ~7);
188 static void cleanup_unknown_header_ext(BlockDriverState
*bs
)
190 BDRVQcowState
*s
= bs
->opaque
;
191 Qcow2UnknownHeaderExtension
*uext
, *next
;
193 QLIST_FOREACH_SAFE(uext
, &s
->unknown_header_ext
, next
, next
) {
194 QLIST_REMOVE(uext
, next
);
199 static void GCC_FMT_ATTR(3, 4) report_unsupported(BlockDriverState
*bs
,
200 Error
**errp
, const char *fmt
, ...)
206 vsnprintf(msg
, sizeof(msg
), fmt
, ap
);
209 error_setg(errp
, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE
,
210 bdrv_get_device_or_node_name(bs
), "qcow2", msg
);
213 static void report_unsupported_feature(BlockDriverState
*bs
,
214 Error
**errp
, Qcow2Feature
*table
, uint64_t mask
)
216 char *features
= g_strdup("");
219 while (table
&& table
->name
[0] != '\0') {
220 if (table
->type
== QCOW2_FEAT_TYPE_INCOMPATIBLE
) {
221 if (mask
& (1ULL << table
->bit
)) {
223 features
= g_strdup_printf("%s%s%.46s", old
, *old
? ", " : "",
226 mask
&= ~(1ULL << table
->bit
);
234 features
= g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64
,
235 old
, *old
? ", " : "", mask
);
239 report_unsupported(bs
, errp
, "%s", features
);
244 * Sets the dirty bit and flushes afterwards if necessary.
246 * The incompatible_features bit is only set if the image file header was
247 * updated successfully. Therefore it is not required to check the return
248 * value of this function.
250 int qcow2_mark_dirty(BlockDriverState
*bs
)
252 BDRVQcowState
*s
= bs
->opaque
;
256 assert(s
->qcow_version
>= 3);
258 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
259 return 0; /* already dirty */
262 val
= cpu_to_be64(s
->incompatible_features
| QCOW2_INCOMPAT_DIRTY
);
263 ret
= bdrv_pwrite(bs
->file
, offsetof(QCowHeader
, incompatible_features
),
268 ret
= bdrv_flush(bs
->file
);
273 /* Only treat image as dirty if the header was updated successfully */
274 s
->incompatible_features
|= QCOW2_INCOMPAT_DIRTY
;
279 * Clears the dirty bit and flushes before if necessary. Only call this
280 * function when there are no pending requests, it does not guard against
281 * concurrent requests dirtying the image.
283 static int qcow2_mark_clean(BlockDriverState
*bs
)
285 BDRVQcowState
*s
= bs
->opaque
;
287 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
290 s
->incompatible_features
&= ~QCOW2_INCOMPAT_DIRTY
;
292 ret
= bdrv_flush(bs
);
297 return qcow2_update_header(bs
);
303 * Marks the image as corrupt.
305 int qcow2_mark_corrupt(BlockDriverState
*bs
)
307 BDRVQcowState
*s
= bs
->opaque
;
309 s
->incompatible_features
|= QCOW2_INCOMPAT_CORRUPT
;
310 return qcow2_update_header(bs
);
314 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
315 * before if necessary.
317 int qcow2_mark_consistent(BlockDriverState
*bs
)
319 BDRVQcowState
*s
= bs
->opaque
;
321 if (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
) {
322 int ret
= bdrv_flush(bs
);
327 s
->incompatible_features
&= ~QCOW2_INCOMPAT_CORRUPT
;
328 return qcow2_update_header(bs
);
333 static int qcow2_check(BlockDriverState
*bs
, BdrvCheckResult
*result
,
336 int ret
= qcow2_check_refcounts(bs
, result
, fix
);
341 if (fix
&& result
->check_errors
== 0 && result
->corruptions
== 0) {
342 ret
= qcow2_mark_clean(bs
);
346 return qcow2_mark_consistent(bs
);
351 static int validate_table_offset(BlockDriverState
*bs
, uint64_t offset
,
352 uint64_t entries
, size_t entry_len
)
354 BDRVQcowState
*s
= bs
->opaque
;
357 /* Use signed INT64_MAX as the maximum even for uint64_t header fields,
358 * because values will be passed to qemu functions taking int64_t. */
359 if (entries
> INT64_MAX
/ entry_len
) {
363 size
= entries
* entry_len
;
365 if (INT64_MAX
- size
< offset
) {
369 /* Tables must be cluster aligned */
370 if (offset
& (s
->cluster_size
- 1)) {
377 static QemuOptsList qcow2_runtime_opts
= {
379 .head
= QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts
.head
),
382 .name
= QCOW2_OPT_LAZY_REFCOUNTS
,
383 .type
= QEMU_OPT_BOOL
,
384 .help
= "Postpone refcount updates",
387 .name
= QCOW2_OPT_DISCARD_REQUEST
,
388 .type
= QEMU_OPT_BOOL
,
389 .help
= "Pass guest discard requests to the layer below",
392 .name
= QCOW2_OPT_DISCARD_SNAPSHOT
,
393 .type
= QEMU_OPT_BOOL
,
394 .help
= "Generate discard requests when snapshot related space "
398 .name
= QCOW2_OPT_DISCARD_OTHER
,
399 .type
= QEMU_OPT_BOOL
,
400 .help
= "Generate discard requests when other clusters are freed",
403 .name
= QCOW2_OPT_OVERLAP
,
404 .type
= QEMU_OPT_STRING
,
405 .help
= "Selects which overlap checks to perform from a range of "
406 "templates (none, constant, cached, all)",
409 .name
= QCOW2_OPT_OVERLAP_TEMPLATE
,
410 .type
= QEMU_OPT_STRING
,
411 .help
= "Selects which overlap checks to perform from a range of "
412 "templates (none, constant, cached, all)",
415 .name
= QCOW2_OPT_OVERLAP_MAIN_HEADER
,
416 .type
= QEMU_OPT_BOOL
,
417 .help
= "Check for unintended writes into the main qcow2 header",
420 .name
= QCOW2_OPT_OVERLAP_ACTIVE_L1
,
421 .type
= QEMU_OPT_BOOL
,
422 .help
= "Check for unintended writes into the active L1 table",
425 .name
= QCOW2_OPT_OVERLAP_ACTIVE_L2
,
426 .type
= QEMU_OPT_BOOL
,
427 .help
= "Check for unintended writes into an active L2 table",
430 .name
= QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
,
431 .type
= QEMU_OPT_BOOL
,
432 .help
= "Check for unintended writes into the refcount table",
435 .name
= QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
,
436 .type
= QEMU_OPT_BOOL
,
437 .help
= "Check for unintended writes into a refcount block",
440 .name
= QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
,
441 .type
= QEMU_OPT_BOOL
,
442 .help
= "Check for unintended writes into the snapshot table",
445 .name
= QCOW2_OPT_OVERLAP_INACTIVE_L1
,
446 .type
= QEMU_OPT_BOOL
,
447 .help
= "Check for unintended writes into an inactive L1 table",
450 .name
= QCOW2_OPT_OVERLAP_INACTIVE_L2
,
451 .type
= QEMU_OPT_BOOL
,
452 .help
= "Check for unintended writes into an inactive L2 table",
455 .name
= QCOW2_OPT_CACHE_SIZE
,
456 .type
= QEMU_OPT_SIZE
,
457 .help
= "Maximum combined metadata (L2 tables and refcount blocks) "
461 .name
= QCOW2_OPT_L2_CACHE_SIZE
,
462 .type
= QEMU_OPT_SIZE
,
463 .help
= "Maximum L2 table cache size",
466 .name
= QCOW2_OPT_REFCOUNT_CACHE_SIZE
,
467 .type
= QEMU_OPT_SIZE
,
468 .help
= "Maximum refcount block cache size",
470 { /* end of list */ }
474 static const char *overlap_bool_option_names
[QCOW2_OL_MAX_BITNR
] = {
475 [QCOW2_OL_MAIN_HEADER_BITNR
] = QCOW2_OPT_OVERLAP_MAIN_HEADER
,
476 [QCOW2_OL_ACTIVE_L1_BITNR
] = QCOW2_OPT_OVERLAP_ACTIVE_L1
,
477 [QCOW2_OL_ACTIVE_L2_BITNR
] = QCOW2_OPT_OVERLAP_ACTIVE_L2
,
478 [QCOW2_OL_REFCOUNT_TABLE_BITNR
] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
,
479 [QCOW2_OL_REFCOUNT_BLOCK_BITNR
] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
,
480 [QCOW2_OL_SNAPSHOT_TABLE_BITNR
] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
,
481 [QCOW2_OL_INACTIVE_L1_BITNR
] = QCOW2_OPT_OVERLAP_INACTIVE_L1
,
482 [QCOW2_OL_INACTIVE_L2_BITNR
] = QCOW2_OPT_OVERLAP_INACTIVE_L2
,
485 static void read_cache_sizes(BlockDriverState
*bs
, QemuOpts
*opts
,
486 uint64_t *l2_cache_size
,
487 uint64_t *refcount_cache_size
, Error
**errp
)
489 BDRVQcowState
*s
= bs
->opaque
;
490 uint64_t combined_cache_size
;
491 bool l2_cache_size_set
, refcount_cache_size_set
, combined_cache_size_set
;
493 combined_cache_size_set
= qemu_opt_get(opts
, QCOW2_OPT_CACHE_SIZE
);
494 l2_cache_size_set
= qemu_opt_get(opts
, QCOW2_OPT_L2_CACHE_SIZE
);
495 refcount_cache_size_set
= qemu_opt_get(opts
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
);
497 combined_cache_size
= qemu_opt_get_size(opts
, QCOW2_OPT_CACHE_SIZE
, 0);
498 *l2_cache_size
= qemu_opt_get_size(opts
, QCOW2_OPT_L2_CACHE_SIZE
, 0);
499 *refcount_cache_size
= qemu_opt_get_size(opts
,
500 QCOW2_OPT_REFCOUNT_CACHE_SIZE
, 0);
502 if (combined_cache_size_set
) {
503 if (l2_cache_size_set
&& refcount_cache_size_set
) {
504 error_setg(errp
, QCOW2_OPT_CACHE_SIZE
", " QCOW2_OPT_L2_CACHE_SIZE
505 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE
" may not be set "
508 } else if (*l2_cache_size
> combined_cache_size
) {
509 error_setg(errp
, QCOW2_OPT_L2_CACHE_SIZE
" may not exceed "
510 QCOW2_OPT_CACHE_SIZE
);
512 } else if (*refcount_cache_size
> combined_cache_size
) {
513 error_setg(errp
, QCOW2_OPT_REFCOUNT_CACHE_SIZE
" may not exceed "
514 QCOW2_OPT_CACHE_SIZE
);
518 if (l2_cache_size_set
) {
519 *refcount_cache_size
= combined_cache_size
- *l2_cache_size
;
520 } else if (refcount_cache_size_set
) {
521 *l2_cache_size
= combined_cache_size
- *refcount_cache_size
;
523 *refcount_cache_size
= combined_cache_size
524 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO
+ 1);
525 *l2_cache_size
= combined_cache_size
- *refcount_cache_size
;
528 if (!l2_cache_size_set
&& !refcount_cache_size_set
) {
529 *l2_cache_size
= MAX(DEFAULT_L2_CACHE_BYTE_SIZE
,
530 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS
532 *refcount_cache_size
= *l2_cache_size
533 / DEFAULT_L2_REFCOUNT_SIZE_RATIO
;
534 } else if (!l2_cache_size_set
) {
535 *l2_cache_size
= *refcount_cache_size
536 * DEFAULT_L2_REFCOUNT_SIZE_RATIO
;
537 } else if (!refcount_cache_size_set
) {
538 *refcount_cache_size
= *l2_cache_size
539 / DEFAULT_L2_REFCOUNT_SIZE_RATIO
;
544 static int qcow2_open(BlockDriverState
*bs
, QDict
*options
, int flags
,
547 BDRVQcowState
*s
= bs
->opaque
;
551 QemuOpts
*opts
= NULL
;
552 Error
*local_err
= NULL
;
554 uint64_t l1_vm_state_index
;
555 const char *opt_overlap_check
, *opt_overlap_check_template
;
556 int overlap_check_template
= 0;
557 uint64_t l2_cache_size
, refcount_cache_size
;
559 ret
= bdrv_pread(bs
->file
, 0, &header
, sizeof(header
));
561 error_setg_errno(errp
, -ret
, "Could not read qcow2 header");
564 be32_to_cpus(&header
.magic
);
565 be32_to_cpus(&header
.version
);
566 be64_to_cpus(&header
.backing_file_offset
);
567 be32_to_cpus(&header
.backing_file_size
);
568 be64_to_cpus(&header
.size
);
569 be32_to_cpus(&header
.cluster_bits
);
570 be32_to_cpus(&header
.crypt_method
);
571 be64_to_cpus(&header
.l1_table_offset
);
572 be32_to_cpus(&header
.l1_size
);
573 be64_to_cpus(&header
.refcount_table_offset
);
574 be32_to_cpus(&header
.refcount_table_clusters
);
575 be64_to_cpus(&header
.snapshots_offset
);
576 be32_to_cpus(&header
.nb_snapshots
);
578 if (header
.magic
!= QCOW_MAGIC
) {
579 error_setg(errp
, "Image is not in qcow2 format");
583 if (header
.version
< 2 || header
.version
> 3) {
584 report_unsupported(bs
, errp
, "QCOW version %" PRIu32
, header
.version
);
589 s
->qcow_version
= header
.version
;
591 /* Initialise cluster size */
592 if (header
.cluster_bits
< MIN_CLUSTER_BITS
||
593 header
.cluster_bits
> MAX_CLUSTER_BITS
) {
594 error_setg(errp
, "Unsupported cluster size: 2^%" PRIu32
,
595 header
.cluster_bits
);
600 s
->cluster_bits
= header
.cluster_bits
;
601 s
->cluster_size
= 1 << s
->cluster_bits
;
602 s
->cluster_sectors
= 1 << (s
->cluster_bits
- 9);
604 /* Initialise version 3 header fields */
605 if (header
.version
== 2) {
606 header
.incompatible_features
= 0;
607 header
.compatible_features
= 0;
608 header
.autoclear_features
= 0;
609 header
.refcount_order
= 4;
610 header
.header_length
= 72;
612 be64_to_cpus(&header
.incompatible_features
);
613 be64_to_cpus(&header
.compatible_features
);
614 be64_to_cpus(&header
.autoclear_features
);
615 be32_to_cpus(&header
.refcount_order
);
616 be32_to_cpus(&header
.header_length
);
618 if (header
.header_length
< 104) {
619 error_setg(errp
, "qcow2 header too short");
625 if (header
.header_length
> s
->cluster_size
) {
626 error_setg(errp
, "qcow2 header exceeds cluster size");
631 if (header
.header_length
> sizeof(header
)) {
632 s
->unknown_header_fields_size
= header
.header_length
- sizeof(header
);
633 s
->unknown_header_fields
= g_malloc(s
->unknown_header_fields_size
);
634 ret
= bdrv_pread(bs
->file
, sizeof(header
), s
->unknown_header_fields
,
635 s
->unknown_header_fields_size
);
637 error_setg_errno(errp
, -ret
, "Could not read unknown qcow2 header "
643 if (header
.backing_file_offset
> s
->cluster_size
) {
644 error_setg(errp
, "Invalid backing file offset");
649 if (header
.backing_file_offset
) {
650 ext_end
= header
.backing_file_offset
;
652 ext_end
= 1 << header
.cluster_bits
;
655 /* Handle feature bits */
656 s
->incompatible_features
= header
.incompatible_features
;
657 s
->compatible_features
= header
.compatible_features
;
658 s
->autoclear_features
= header
.autoclear_features
;
660 if (s
->incompatible_features
& ~QCOW2_INCOMPAT_MASK
) {
661 void *feature_table
= NULL
;
662 qcow2_read_extensions(bs
, header
.header_length
, ext_end
,
663 &feature_table
, NULL
);
664 report_unsupported_feature(bs
, errp
, feature_table
,
665 s
->incompatible_features
&
666 ~QCOW2_INCOMPAT_MASK
);
668 g_free(feature_table
);
672 if (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
) {
673 /* Corrupt images may not be written to unless they are being repaired
675 if ((flags
& BDRV_O_RDWR
) && !(flags
& BDRV_O_CHECK
)) {
676 error_setg(errp
, "qcow2: Image is corrupt; cannot be opened "
683 /* Check support for various header values */
684 if (header
.refcount_order
> 6) {
685 error_setg(errp
, "Reference count entry width too large; may not "
690 s
->refcount_order
= header
.refcount_order
;
691 s
->refcount_bits
= 1 << s
->refcount_order
;
692 s
->refcount_max
= UINT64_C(1) << (s
->refcount_bits
- 1);
693 s
->refcount_max
+= s
->refcount_max
- 1;
695 if (header
.crypt_method
> QCOW_CRYPT_AES
) {
696 error_setg(errp
, "Unsupported encryption method: %" PRIu32
,
697 header
.crypt_method
);
701 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128
)) {
702 error_setg(errp
, "AES cipher not available");
706 s
->crypt_method_header
= header
.crypt_method
;
707 if (s
->crypt_method_header
) {
711 s
->l2_bits
= s
->cluster_bits
- 3; /* L2 is always one cluster */
712 s
->l2_size
= 1 << s
->l2_bits
;
713 /* 2^(s->refcount_order - 3) is the refcount width in bytes */
714 s
->refcount_block_bits
= s
->cluster_bits
- (s
->refcount_order
- 3);
715 s
->refcount_block_size
= 1 << s
->refcount_block_bits
;
716 bs
->total_sectors
= header
.size
/ 512;
717 s
->csize_shift
= (62 - (s
->cluster_bits
- 8));
718 s
->csize_mask
= (1 << (s
->cluster_bits
- 8)) - 1;
719 s
->cluster_offset_mask
= (1LL << s
->csize_shift
) - 1;
721 s
->refcount_table_offset
= header
.refcount_table_offset
;
722 s
->refcount_table_size
=
723 header
.refcount_table_clusters
<< (s
->cluster_bits
- 3);
725 if (header
.refcount_table_clusters
> qcow2_max_refcount_clusters(s
)) {
726 error_setg(errp
, "Reference count table too large");
731 ret
= validate_table_offset(bs
, s
->refcount_table_offset
,
732 s
->refcount_table_size
, sizeof(uint64_t));
734 error_setg(errp
, "Invalid reference count table offset");
738 /* Snapshot table offset/length */
739 if (header
.nb_snapshots
> QCOW_MAX_SNAPSHOTS
) {
740 error_setg(errp
, "Too many snapshots");
745 ret
= validate_table_offset(bs
, header
.snapshots_offset
,
747 sizeof(QCowSnapshotHeader
));
749 error_setg(errp
, "Invalid snapshot table offset");
753 /* read the level 1 table */
754 if (header
.l1_size
> QCOW_MAX_L1_SIZE
/ sizeof(uint64_t)) {
755 error_setg(errp
, "Active L1 table too large");
759 s
->l1_size
= header
.l1_size
;
761 l1_vm_state_index
= size_to_l1(s
, header
.size
);
762 if (l1_vm_state_index
> INT_MAX
) {
763 error_setg(errp
, "Image is too big");
767 s
->l1_vm_state_index
= l1_vm_state_index
;
769 /* the L1 table must contain at least enough entries to put
771 if (s
->l1_size
< s
->l1_vm_state_index
) {
772 error_setg(errp
, "L1 table is too small");
777 ret
= validate_table_offset(bs
, header
.l1_table_offset
,
778 header
.l1_size
, sizeof(uint64_t));
780 error_setg(errp
, "Invalid L1 table offset");
783 s
->l1_table_offset
= header
.l1_table_offset
;
786 if (s
->l1_size
> 0) {
787 s
->l1_table
= qemu_try_blockalign(bs
->file
,
788 align_offset(s
->l1_size
* sizeof(uint64_t), 512));
789 if (s
->l1_table
== NULL
) {
790 error_setg(errp
, "Could not allocate L1 table");
794 ret
= bdrv_pread(bs
->file
, s
->l1_table_offset
, s
->l1_table
,
795 s
->l1_size
* sizeof(uint64_t));
797 error_setg_errno(errp
, -ret
, "Could not read L1 table");
800 for(i
= 0;i
< s
->l1_size
; i
++) {
801 be64_to_cpus(&s
->l1_table
[i
]);
805 /* get L2 table/refcount block cache size from command line options */
806 opts
= qemu_opts_create(&qcow2_runtime_opts
, NULL
, 0, &error_abort
);
807 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
809 error_propagate(errp
, local_err
);
814 read_cache_sizes(bs
, opts
, &l2_cache_size
, &refcount_cache_size
,
817 error_propagate(errp
, local_err
);
822 l2_cache_size
/= s
->cluster_size
;
823 if (l2_cache_size
< MIN_L2_CACHE_SIZE
) {
824 l2_cache_size
= MIN_L2_CACHE_SIZE
;
826 if (l2_cache_size
> INT_MAX
) {
827 error_setg(errp
, "L2 cache size too big");
832 refcount_cache_size
/= s
->cluster_size
;
833 if (refcount_cache_size
< MIN_REFCOUNT_CACHE_SIZE
) {
834 refcount_cache_size
= MIN_REFCOUNT_CACHE_SIZE
;
836 if (refcount_cache_size
> INT_MAX
) {
837 error_setg(errp
, "Refcount cache size too big");
842 /* alloc L2 table/refcount block cache */
843 s
->l2_table_cache
= qcow2_cache_create(bs
, l2_cache_size
);
844 s
->refcount_block_cache
= qcow2_cache_create(bs
, refcount_cache_size
);
845 if (s
->l2_table_cache
== NULL
|| s
->refcount_block_cache
== NULL
) {
846 error_setg(errp
, "Could not allocate metadata caches");
851 s
->cluster_cache
= g_malloc(s
->cluster_size
);
852 /* one more sector for decompressed data alignment */
853 s
->cluster_data
= qemu_try_blockalign(bs
->file
, QCOW_MAX_CRYPT_CLUSTERS
854 * s
->cluster_size
+ 512);
855 if (s
->cluster_data
== NULL
) {
856 error_setg(errp
, "Could not allocate temporary cluster buffer");
861 s
->cluster_cache_offset
= -1;
864 ret
= qcow2_refcount_init(bs
);
866 error_setg_errno(errp
, -ret
, "Could not initialize refcount handling");
870 QLIST_INIT(&s
->cluster_allocs
);
871 QTAILQ_INIT(&s
->discards
);
873 /* read qcow2 extensions */
874 if (qcow2_read_extensions(bs
, header
.header_length
, ext_end
, NULL
,
876 error_propagate(errp
, local_err
);
881 /* read the backing file name */
882 if (header
.backing_file_offset
!= 0) {
883 len
= header
.backing_file_size
;
884 if (len
> MIN(1023, s
->cluster_size
- header
.backing_file_offset
) ||
885 len
>= sizeof(bs
->backing_file
)) {
886 error_setg(errp
, "Backing file name too long");
890 ret
= bdrv_pread(bs
->file
, header
.backing_file_offset
,
891 bs
->backing_file
, len
);
893 error_setg_errno(errp
, -ret
, "Could not read backing file name");
896 bs
->backing_file
[len
] = '\0';
897 s
->image_backing_file
= g_strdup(bs
->backing_file
);
900 /* Internal snapshots */
901 s
->snapshots_offset
= header
.snapshots_offset
;
902 s
->nb_snapshots
= header
.nb_snapshots
;
904 ret
= qcow2_read_snapshots(bs
);
906 error_setg_errno(errp
, -ret
, "Could not read snapshots");
910 /* Clear unknown autoclear feature bits */
911 if (!bs
->read_only
&& !(flags
& BDRV_O_INCOMING
) && s
->autoclear_features
) {
912 s
->autoclear_features
= 0;
913 ret
= qcow2_update_header(bs
);
915 error_setg_errno(errp
, -ret
, "Could not update qcow2 header");
920 /* Initialise locks */
921 qemu_co_mutex_init(&s
->lock
);
923 /* Repair image if dirty */
924 if (!(flags
& (BDRV_O_CHECK
| BDRV_O_INCOMING
)) && !bs
->read_only
&&
925 (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
)) {
926 BdrvCheckResult result
= {0};
928 ret
= qcow2_check(bs
, &result
, BDRV_FIX_ERRORS
| BDRV_FIX_LEAKS
);
930 error_setg_errno(errp
, -ret
, "Could not repair dirty image");
935 /* Enable lazy_refcounts according to image and command line options */
936 s
->use_lazy_refcounts
= qemu_opt_get_bool(opts
, QCOW2_OPT_LAZY_REFCOUNTS
,
937 (s
->compatible_features
& QCOW2_COMPAT_LAZY_REFCOUNTS
));
939 s
->discard_passthrough
[QCOW2_DISCARD_NEVER
] = false;
940 s
->discard_passthrough
[QCOW2_DISCARD_ALWAYS
] = true;
941 s
->discard_passthrough
[QCOW2_DISCARD_REQUEST
] =
942 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_REQUEST
,
943 flags
& BDRV_O_UNMAP
);
944 s
->discard_passthrough
[QCOW2_DISCARD_SNAPSHOT
] =
945 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_SNAPSHOT
, true);
946 s
->discard_passthrough
[QCOW2_DISCARD_OTHER
] =
947 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_OTHER
, false);
949 opt_overlap_check
= qemu_opt_get(opts
, QCOW2_OPT_OVERLAP
);
950 opt_overlap_check_template
= qemu_opt_get(opts
, QCOW2_OPT_OVERLAP_TEMPLATE
);
951 if (opt_overlap_check_template
&& opt_overlap_check
&&
952 strcmp(opt_overlap_check_template
, opt_overlap_check
))
954 error_setg(errp
, "Conflicting values for qcow2 options '"
955 QCOW2_OPT_OVERLAP
"' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
956 "' ('%s')", opt_overlap_check
, opt_overlap_check_template
);
960 if (!opt_overlap_check
) {
961 opt_overlap_check
= opt_overlap_check_template
?: "cached";
964 if (!strcmp(opt_overlap_check
, "none")) {
965 overlap_check_template
= 0;
966 } else if (!strcmp(opt_overlap_check
, "constant")) {
967 overlap_check_template
= QCOW2_OL_CONSTANT
;
968 } else if (!strcmp(opt_overlap_check
, "cached")) {
969 overlap_check_template
= QCOW2_OL_CACHED
;
970 } else if (!strcmp(opt_overlap_check
, "all")) {
971 overlap_check_template
= QCOW2_OL_ALL
;
973 error_setg(errp
, "Unsupported value '%s' for qcow2 option "
974 "'overlap-check'. Allowed are either of the following: "
975 "none, constant, cached, all", opt_overlap_check
);
980 s
->overlap_check
= 0;
981 for (i
= 0; i
< QCOW2_OL_MAX_BITNR
; i
++) {
982 /* overlap-check defines a template bitmask, but every flag may be
983 * overwritten through the associated boolean option */
985 qemu_opt_get_bool(opts
, overlap_bool_option_names
[i
],
986 overlap_check_template
& (1 << i
)) << i
;
992 if (s
->use_lazy_refcounts
&& s
->qcow_version
< 3) {
993 error_setg(errp
, "Lazy refcounts require a qcow2 image with at least "
994 "qemu 1.1 compatibility level");
1001 BdrvCheckResult result
= {0};
1002 qcow2_check_refcounts(bs
, &result
, 0);
1008 qemu_opts_del(opts
);
1009 g_free(s
->unknown_header_fields
);
1010 cleanup_unknown_header_ext(bs
);
1011 qcow2_free_snapshots(bs
);
1012 qcow2_refcount_close(bs
);
1013 qemu_vfree(s
->l1_table
);
1014 /* else pre-write overlap checks in cache_destroy may crash */
1016 if (s
->l2_table_cache
) {
1017 qcow2_cache_destroy(bs
, s
->l2_table_cache
);
1019 if (s
->refcount_block_cache
) {
1020 qcow2_cache_destroy(bs
, s
->refcount_block_cache
);
1022 g_free(s
->cluster_cache
);
1023 qemu_vfree(s
->cluster_data
);
1027 static void qcow2_refresh_limits(BlockDriverState
*bs
, Error
**errp
)
1029 BDRVQcowState
*s
= bs
->opaque
;
1031 bs
->bl
.write_zeroes_alignment
= s
->cluster_sectors
;
1034 static int qcow2_set_key(BlockDriverState
*bs
, const char *key
)
1036 BDRVQcowState
*s
= bs
->opaque
;
1041 memset(keybuf
, 0, 16);
1045 /* XXX: we could compress the chars to 7 bits to increase
1047 for(i
= 0;i
< len
;i
++) {
1050 assert(bs
->encrypted
);
1052 qcrypto_cipher_free(s
->cipher
);
1053 s
->cipher
= qcrypto_cipher_new(
1054 QCRYPTO_CIPHER_ALG_AES_128
,
1055 QCRYPTO_CIPHER_MODE_CBC
,
1056 keybuf
, G_N_ELEMENTS(keybuf
),
1060 /* XXX would be nice if errors in this method could
1061 * be properly propagate to the caller. Would need
1062 * the bdrv_set_key() API signature to be fixed. */
1069 /* We have no actual commit/abort logic for qcow2, but we need to write out any
1070 * unwritten data if we reopen read-only. */
1071 static int qcow2_reopen_prepare(BDRVReopenState
*state
,
1072 BlockReopenQueue
*queue
, Error
**errp
)
1076 if ((state
->flags
& BDRV_O_RDWR
) == 0) {
1077 ret
= bdrv_flush(state
->bs
);
1082 ret
= qcow2_mark_clean(state
->bs
);
1091 static int64_t coroutine_fn
qcow2_co_get_block_status(BlockDriverState
*bs
,
1092 int64_t sector_num
, int nb_sectors
, int *pnum
)
1094 BDRVQcowState
*s
= bs
->opaque
;
1095 uint64_t cluster_offset
;
1096 int index_in_cluster
, ret
;
1100 qemu_co_mutex_lock(&s
->lock
);
1101 ret
= qcow2_get_cluster_offset(bs
, sector_num
<< 9, pnum
, &cluster_offset
);
1102 qemu_co_mutex_unlock(&s
->lock
);
1107 if (cluster_offset
!= 0 && ret
!= QCOW2_CLUSTER_COMPRESSED
&&
1109 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1110 cluster_offset
|= (index_in_cluster
<< BDRV_SECTOR_BITS
);
1111 status
|= BDRV_BLOCK_OFFSET_VALID
| cluster_offset
;
1113 if (ret
== QCOW2_CLUSTER_ZERO
) {
1114 status
|= BDRV_BLOCK_ZERO
;
1115 } else if (ret
!= QCOW2_CLUSTER_UNALLOCATED
) {
1116 status
|= BDRV_BLOCK_DATA
;
1121 /* handle reading after the end of the backing file */
1122 int qcow2_backing_read1(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
1123 int64_t sector_num
, int nb_sectors
)
1126 if ((sector_num
+ nb_sectors
) <= bs
->total_sectors
)
1128 if (sector_num
>= bs
->total_sectors
)
1131 n1
= bs
->total_sectors
- sector_num
;
1133 qemu_iovec_memset(qiov
, 512 * n1
, 0, 512 * (nb_sectors
- n1
));
1138 static coroutine_fn
int qcow2_co_readv(BlockDriverState
*bs
, int64_t sector_num
,
1139 int remaining_sectors
, QEMUIOVector
*qiov
)
1141 BDRVQcowState
*s
= bs
->opaque
;
1142 int index_in_cluster
, n1
;
1144 int cur_nr_sectors
; /* number of sectors in current iteration */
1145 uint64_t cluster_offset
= 0;
1146 uint64_t bytes_done
= 0;
1147 QEMUIOVector hd_qiov
;
1148 uint8_t *cluster_data
= NULL
;
1150 qemu_iovec_init(&hd_qiov
, qiov
->niov
);
1152 qemu_co_mutex_lock(&s
->lock
);
1154 while (remaining_sectors
!= 0) {
1156 /* prepare next request */
1157 cur_nr_sectors
= remaining_sectors
;
1159 cur_nr_sectors
= MIN(cur_nr_sectors
,
1160 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
);
1163 ret
= qcow2_get_cluster_offset(bs
, sector_num
<< 9,
1164 &cur_nr_sectors
, &cluster_offset
);
1169 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1171 qemu_iovec_reset(&hd_qiov
);
1172 qemu_iovec_concat(&hd_qiov
, qiov
, bytes_done
,
1173 cur_nr_sectors
* 512);
1176 case QCOW2_CLUSTER_UNALLOCATED
:
1178 if (bs
->backing_hd
) {
1179 /* read from the base image */
1180 n1
= qcow2_backing_read1(bs
->backing_hd
, &hd_qiov
,
1181 sector_num
, cur_nr_sectors
);
1183 QEMUIOVector local_qiov
;
1185 qemu_iovec_init(&local_qiov
, hd_qiov
.niov
);
1186 qemu_iovec_concat(&local_qiov
, &hd_qiov
, 0,
1187 n1
* BDRV_SECTOR_SIZE
);
1189 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_BACKING_AIO
);
1190 qemu_co_mutex_unlock(&s
->lock
);
1191 ret
= bdrv_co_readv(bs
->backing_hd
, sector_num
,
1193 qemu_co_mutex_lock(&s
->lock
);
1195 qemu_iovec_destroy(&local_qiov
);
1202 /* Note: in this case, no need to wait */
1203 qemu_iovec_memset(&hd_qiov
, 0, 0, 512 * cur_nr_sectors
);
1207 case QCOW2_CLUSTER_ZERO
:
1208 qemu_iovec_memset(&hd_qiov
, 0, 0, 512 * cur_nr_sectors
);
1211 case QCOW2_CLUSTER_COMPRESSED
:
1212 /* add AIO support for compressed blocks ? */
1213 ret
= qcow2_decompress_cluster(bs
, cluster_offset
);
1218 qemu_iovec_from_buf(&hd_qiov
, 0,
1219 s
->cluster_cache
+ index_in_cluster
* 512,
1220 512 * cur_nr_sectors
);
1223 case QCOW2_CLUSTER_NORMAL
:
1224 if ((cluster_offset
& 511) != 0) {
1229 if (bs
->encrypted
) {
1233 * For encrypted images, read everything into a temporary
1234 * contiguous buffer on which the AES functions can work.
1236 if (!cluster_data
) {
1238 qemu_try_blockalign(bs
->file
, QCOW_MAX_CRYPT_CLUSTERS
1240 if (cluster_data
== NULL
) {
1246 assert(cur_nr_sectors
<=
1247 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
);
1248 qemu_iovec_reset(&hd_qiov
);
1249 qemu_iovec_add(&hd_qiov
, cluster_data
,
1250 512 * cur_nr_sectors
);
1253 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_AIO
);
1254 qemu_co_mutex_unlock(&s
->lock
);
1255 ret
= bdrv_co_readv(bs
->file
,
1256 (cluster_offset
>> 9) + index_in_cluster
,
1257 cur_nr_sectors
, &hd_qiov
);
1258 qemu_co_mutex_lock(&s
->lock
);
1262 if (bs
->encrypted
) {
1265 if (qcow2_encrypt_sectors(s
, sector_num
, cluster_data
,
1266 cluster_data
, cur_nr_sectors
, false,
1272 qemu_iovec_from_buf(qiov
, bytes_done
,
1273 cluster_data
, 512 * cur_nr_sectors
);
1278 g_assert_not_reached();
1283 remaining_sectors
-= cur_nr_sectors
;
1284 sector_num
+= cur_nr_sectors
;
1285 bytes_done
+= cur_nr_sectors
* 512;
1290 qemu_co_mutex_unlock(&s
->lock
);
1292 qemu_iovec_destroy(&hd_qiov
);
1293 qemu_vfree(cluster_data
);
1298 static coroutine_fn
int qcow2_co_writev(BlockDriverState
*bs
,
1300 int remaining_sectors
,
1303 BDRVQcowState
*s
= bs
->opaque
;
1304 int index_in_cluster
;
1306 int cur_nr_sectors
; /* number of sectors in current iteration */
1307 uint64_t cluster_offset
;
1308 QEMUIOVector hd_qiov
;
1309 uint64_t bytes_done
= 0;
1310 uint8_t *cluster_data
= NULL
;
1311 QCowL2Meta
*l2meta
= NULL
;
1313 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num
,
1316 qemu_iovec_init(&hd_qiov
, qiov
->niov
);
1318 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1320 qemu_co_mutex_lock(&s
->lock
);
1322 while (remaining_sectors
!= 0) {
1326 trace_qcow2_writev_start_part(qemu_coroutine_self());
1327 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1328 cur_nr_sectors
= remaining_sectors
;
1329 if (bs
->encrypted
&&
1331 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
- index_in_cluster
) {
1333 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
- index_in_cluster
;
1336 ret
= qcow2_alloc_cluster_offset(bs
, sector_num
<< 9,
1337 &cur_nr_sectors
, &cluster_offset
, &l2meta
);
1342 assert((cluster_offset
& 511) == 0);
1344 qemu_iovec_reset(&hd_qiov
);
1345 qemu_iovec_concat(&hd_qiov
, qiov
, bytes_done
,
1346 cur_nr_sectors
* 512);
1348 if (bs
->encrypted
) {
1351 if (!cluster_data
) {
1352 cluster_data
= qemu_try_blockalign(bs
->file
,
1353 QCOW_MAX_CRYPT_CLUSTERS
1355 if (cluster_data
== NULL
) {
1361 assert(hd_qiov
.size
<=
1362 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
1363 qemu_iovec_to_buf(&hd_qiov
, 0, cluster_data
, hd_qiov
.size
);
1365 if (qcow2_encrypt_sectors(s
, sector_num
, cluster_data
,
1366 cluster_data
, cur_nr_sectors
,
1373 qemu_iovec_reset(&hd_qiov
);
1374 qemu_iovec_add(&hd_qiov
, cluster_data
,
1375 cur_nr_sectors
* 512);
1378 ret
= qcow2_pre_write_overlap_check(bs
, 0,
1379 cluster_offset
+ index_in_cluster
* BDRV_SECTOR_SIZE
,
1380 cur_nr_sectors
* BDRV_SECTOR_SIZE
);
1385 qemu_co_mutex_unlock(&s
->lock
);
1386 BLKDBG_EVENT(bs
->file
, BLKDBG_WRITE_AIO
);
1387 trace_qcow2_writev_data(qemu_coroutine_self(),
1388 (cluster_offset
>> 9) + index_in_cluster
);
1389 ret
= bdrv_co_writev(bs
->file
,
1390 (cluster_offset
>> 9) + index_in_cluster
,
1391 cur_nr_sectors
, &hd_qiov
);
1392 qemu_co_mutex_lock(&s
->lock
);
1397 while (l2meta
!= NULL
) {
1400 ret
= qcow2_alloc_cluster_link_l2(bs
, l2meta
);
1405 /* Take the request off the list of running requests */
1406 if (l2meta
->nb_clusters
!= 0) {
1407 QLIST_REMOVE(l2meta
, next_in_flight
);
1410 qemu_co_queue_restart_all(&l2meta
->dependent_requests
);
1412 next
= l2meta
->next
;
1417 remaining_sectors
-= cur_nr_sectors
;
1418 sector_num
+= cur_nr_sectors
;
1419 bytes_done
+= cur_nr_sectors
* 512;
1420 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors
);
1425 qemu_co_mutex_unlock(&s
->lock
);
1427 while (l2meta
!= NULL
) {
1430 if (l2meta
->nb_clusters
!= 0) {
1431 QLIST_REMOVE(l2meta
, next_in_flight
);
1433 qemu_co_queue_restart_all(&l2meta
->dependent_requests
);
1435 next
= l2meta
->next
;
1440 qemu_iovec_destroy(&hd_qiov
);
1441 qemu_vfree(cluster_data
);
1442 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret
);
1447 static void qcow2_close(BlockDriverState
*bs
)
1449 BDRVQcowState
*s
= bs
->opaque
;
1450 qemu_vfree(s
->l1_table
);
1451 /* else pre-write overlap checks in cache_destroy may crash */
1454 if (!(bs
->open_flags
& BDRV_O_INCOMING
)) {
1457 ret1
= qcow2_cache_flush(bs
, s
->l2_table_cache
);
1458 ret2
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
1461 error_report("Failed to flush the L2 table cache: %s",
1465 error_report("Failed to flush the refcount block cache: %s",
1469 if (!ret1
&& !ret2
) {
1470 qcow2_mark_clean(bs
);
1474 qcow2_cache_destroy(bs
, s
->l2_table_cache
);
1475 qcow2_cache_destroy(bs
, s
->refcount_block_cache
);
1477 qcrypto_cipher_free(s
->cipher
);
1480 g_free(s
->unknown_header_fields
);
1481 cleanup_unknown_header_ext(bs
);
1483 g_free(s
->image_backing_file
);
1484 g_free(s
->image_backing_format
);
1486 g_free(s
->cluster_cache
);
1487 qemu_vfree(s
->cluster_data
);
1488 qcow2_refcount_close(bs
);
1489 qcow2_free_snapshots(bs
);
1492 static void qcow2_invalidate_cache(BlockDriverState
*bs
, Error
**errp
)
1494 BDRVQcowState
*s
= bs
->opaque
;
1495 int flags
= s
->flags
;
1496 QCryptoCipher
*cipher
= NULL
;
1498 Error
*local_err
= NULL
;
1502 * Backing files are read-only which makes all of their metadata immutable,
1503 * that means we don't have to worry about reopening them here.
1511 bdrv_invalidate_cache(bs
->file
, &local_err
);
1513 error_propagate(errp
, local_err
);
1517 memset(s
, 0, sizeof(BDRVQcowState
));
1518 options
= qdict_clone_shallow(bs
->options
);
1520 ret
= qcow2_open(bs
, options
, flags
, &local_err
);
1523 error_setg(errp
, "Could not reopen qcow2 layer: %s",
1524 error_get_pretty(local_err
));
1525 error_free(local_err
);
1527 } else if (ret
< 0) {
1528 error_setg_errno(errp
, -ret
, "Could not reopen qcow2 layer");
1535 static size_t header_ext_add(char *buf
, uint32_t magic
, const void *s
,
1536 size_t len
, size_t buflen
)
1538 QCowExtension
*ext_backing_fmt
= (QCowExtension
*) buf
;
1539 size_t ext_len
= sizeof(QCowExtension
) + ((len
+ 7) & ~7);
1541 if (buflen
< ext_len
) {
1545 *ext_backing_fmt
= (QCowExtension
) {
1546 .magic
= cpu_to_be32(magic
),
1547 .len
= cpu_to_be32(len
),
1549 memcpy(buf
+ sizeof(QCowExtension
), s
, len
);
1555 * Updates the qcow2 header, including the variable length parts of it, i.e.
1556 * the backing file name and all extensions. qcow2 was not designed to allow
1557 * such changes, so if we run out of space (we can only use the first cluster)
1558 * this function may fail.
1560 * Returns 0 on success, -errno in error cases.
1562 int qcow2_update_header(BlockDriverState
*bs
)
1564 BDRVQcowState
*s
= bs
->opaque
;
1567 size_t buflen
= s
->cluster_size
;
1569 uint64_t total_size
;
1570 uint32_t refcount_table_clusters
;
1571 size_t header_length
;
1572 Qcow2UnknownHeaderExtension
*uext
;
1574 buf
= qemu_blockalign(bs
, buflen
);
1576 /* Header structure */
1577 header
= (QCowHeader
*) buf
;
1579 if (buflen
< sizeof(*header
)) {
1584 header_length
= sizeof(*header
) + s
->unknown_header_fields_size
;
1585 total_size
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
1586 refcount_table_clusters
= s
->refcount_table_size
>> (s
->cluster_bits
- 3);
1588 *header
= (QCowHeader
) {
1589 /* Version 2 fields */
1590 .magic
= cpu_to_be32(QCOW_MAGIC
),
1591 .version
= cpu_to_be32(s
->qcow_version
),
1592 .backing_file_offset
= 0,
1593 .backing_file_size
= 0,
1594 .cluster_bits
= cpu_to_be32(s
->cluster_bits
),
1595 .size
= cpu_to_be64(total_size
),
1596 .crypt_method
= cpu_to_be32(s
->crypt_method_header
),
1597 .l1_size
= cpu_to_be32(s
->l1_size
),
1598 .l1_table_offset
= cpu_to_be64(s
->l1_table_offset
),
1599 .refcount_table_offset
= cpu_to_be64(s
->refcount_table_offset
),
1600 .refcount_table_clusters
= cpu_to_be32(refcount_table_clusters
),
1601 .nb_snapshots
= cpu_to_be32(s
->nb_snapshots
),
1602 .snapshots_offset
= cpu_to_be64(s
->snapshots_offset
),
1604 /* Version 3 fields */
1605 .incompatible_features
= cpu_to_be64(s
->incompatible_features
),
1606 .compatible_features
= cpu_to_be64(s
->compatible_features
),
1607 .autoclear_features
= cpu_to_be64(s
->autoclear_features
),
1608 .refcount_order
= cpu_to_be32(s
->refcount_order
),
1609 .header_length
= cpu_to_be32(header_length
),
1612 /* For older versions, write a shorter header */
1613 switch (s
->qcow_version
) {
1615 ret
= offsetof(QCowHeader
, incompatible_features
);
1618 ret
= sizeof(*header
);
1627 memset(buf
, 0, buflen
);
1629 /* Preserve any unknown field in the header */
1630 if (s
->unknown_header_fields_size
) {
1631 if (buflen
< s
->unknown_header_fields_size
) {
1636 memcpy(buf
, s
->unknown_header_fields
, s
->unknown_header_fields_size
);
1637 buf
+= s
->unknown_header_fields_size
;
1638 buflen
-= s
->unknown_header_fields_size
;
1641 /* Backing file format header extension */
1642 if (s
->image_backing_format
) {
1643 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_BACKING_FORMAT
,
1644 s
->image_backing_format
,
1645 strlen(s
->image_backing_format
),
1656 Qcow2Feature features
[] = {
1658 .type
= QCOW2_FEAT_TYPE_INCOMPATIBLE
,
1659 .bit
= QCOW2_INCOMPAT_DIRTY_BITNR
,
1660 .name
= "dirty bit",
1663 .type
= QCOW2_FEAT_TYPE_INCOMPATIBLE
,
1664 .bit
= QCOW2_INCOMPAT_CORRUPT_BITNR
,
1665 .name
= "corrupt bit",
1668 .type
= QCOW2_FEAT_TYPE_COMPATIBLE
,
1669 .bit
= QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR
,
1670 .name
= "lazy refcounts",
1674 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_FEATURE_TABLE
,
1675 features
, sizeof(features
), buflen
);
1682 /* Keep unknown header extensions */
1683 QLIST_FOREACH(uext
, &s
->unknown_header_ext
, next
) {
1684 ret
= header_ext_add(buf
, uext
->magic
, uext
->data
, uext
->len
, buflen
);
1693 /* End of header extensions */
1694 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_END
, NULL
, 0, buflen
);
1702 /* Backing file name */
1703 if (s
->image_backing_file
) {
1704 size_t backing_file_len
= strlen(s
->image_backing_file
);
1706 if (buflen
< backing_file_len
) {
1711 /* Using strncpy is ok here, since buf is not NUL-terminated. */
1712 strncpy(buf
, s
->image_backing_file
, buflen
);
1714 header
->backing_file_offset
= cpu_to_be64(buf
- ((char*) header
));
1715 header
->backing_file_size
= cpu_to_be32(backing_file_len
);
1718 /* Write the new header */
1719 ret
= bdrv_pwrite(bs
->file
, 0, header
, s
->cluster_size
);
1730 static int qcow2_change_backing_file(BlockDriverState
*bs
,
1731 const char *backing_file
, const char *backing_fmt
)
1733 BDRVQcowState
*s
= bs
->opaque
;
1735 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
1736 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
1738 g_free(s
->image_backing_file
);
1739 g_free(s
->image_backing_format
);
1741 s
->image_backing_file
= backing_file
? g_strdup(bs
->backing_file
) : NULL
;
1742 s
->image_backing_format
= backing_fmt
? g_strdup(bs
->backing_format
) : NULL
;
1744 return qcow2_update_header(bs
);
1747 static int preallocate(BlockDriverState
*bs
)
1749 uint64_t nb_sectors
;
1751 uint64_t host_offset
= 0;
1756 nb_sectors
= bdrv_nb_sectors(bs
);
1759 while (nb_sectors
) {
1760 num
= MIN(nb_sectors
, INT_MAX
>> BDRV_SECTOR_BITS
);
1761 ret
= qcow2_alloc_cluster_offset(bs
, offset
, &num
,
1762 &host_offset
, &meta
);
1768 QCowL2Meta
*next
= meta
->next
;
1770 ret
= qcow2_alloc_cluster_link_l2(bs
, meta
);
1772 qcow2_free_any_clusters(bs
, meta
->alloc_offset
,
1773 meta
->nb_clusters
, QCOW2_DISCARD_NEVER
);
1777 /* There are no dependent requests, but we need to remove our
1778 * request from the list of in-flight requests */
1779 QLIST_REMOVE(meta
, next_in_flight
);
1785 /* TODO Preallocate data if requested */
1788 offset
+= num
<< BDRV_SECTOR_BITS
;
1792 * It is expected that the image file is large enough to actually contain
1793 * all of the allocated clusters (otherwise we get failing reads after
1794 * EOF). Extend the image to the last allocated sector.
1796 if (host_offset
!= 0) {
1797 uint8_t buf
[BDRV_SECTOR_SIZE
];
1798 memset(buf
, 0, BDRV_SECTOR_SIZE
);
1799 ret
= bdrv_write(bs
->file
, (host_offset
>> BDRV_SECTOR_BITS
) + num
- 1,
1809 static int qcow2_create2(const char *filename
, int64_t total_size
,
1810 const char *backing_file
, const char *backing_format
,
1811 int flags
, size_t cluster_size
, PreallocMode prealloc
,
1812 QemuOpts
*opts
, int version
, int refcount_order
,
1815 /* Calculate cluster_bits */
1817 cluster_bits
= ctz32(cluster_size
);
1818 if (cluster_bits
< MIN_CLUSTER_BITS
|| cluster_bits
> MAX_CLUSTER_BITS
||
1819 (1 << cluster_bits
) != cluster_size
)
1821 error_setg(errp
, "Cluster size must be a power of two between %d and "
1822 "%dk", 1 << MIN_CLUSTER_BITS
, 1 << (MAX_CLUSTER_BITS
- 10));
1827 * Open the image file and write a minimal qcow2 header.
1829 * We keep things simple and start with a zero-sized image. We also
1830 * do without refcount blocks or a L1 table for now. We'll fix the
1831 * inconsistency later.
1833 * We do need a refcount table because growing the refcount table means
1834 * allocating two new refcount blocks - the seconds of which would be at
1835 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
1836 * size for any qcow2 image.
1838 BlockDriverState
* bs
;
1840 uint64_t* refcount_table
;
1841 Error
*local_err
= NULL
;
1844 if (prealloc
== PREALLOC_MODE_FULL
|| prealloc
== PREALLOC_MODE_FALLOC
) {
1845 /* Note: The following calculation does not need to be exact; if it is a
1846 * bit off, either some bytes will be "leaked" (which is fine) or we
1847 * will need to increase the file size by some bytes (which is fine,
1848 * too, as long as the bulk is allocated here). Therefore, using
1849 * floating point arithmetic is fine. */
1850 int64_t meta_size
= 0;
1851 uint64_t nreftablee
, nrefblocke
, nl1e
, nl2e
;
1852 int64_t aligned_total_size
= align_offset(total_size
, cluster_size
);
1853 int refblock_bits
, refblock_size
;
1854 /* refcount entry size in bytes */
1855 double rces
= (1 << refcount_order
) / 8.;
1857 /* see qcow2_open() */
1858 refblock_bits
= cluster_bits
- (refcount_order
- 3);
1859 refblock_size
= 1 << refblock_bits
;
1861 /* header: 1 cluster */
1862 meta_size
+= cluster_size
;
1864 /* total size of L2 tables */
1865 nl2e
= aligned_total_size
/ cluster_size
;
1866 nl2e
= align_offset(nl2e
, cluster_size
/ sizeof(uint64_t));
1867 meta_size
+= nl2e
* sizeof(uint64_t);
1869 /* total size of L1 tables */
1870 nl1e
= nl2e
* sizeof(uint64_t) / cluster_size
;
1871 nl1e
= align_offset(nl1e
, cluster_size
/ sizeof(uint64_t));
1872 meta_size
+= nl1e
* sizeof(uint64_t);
1874 /* total size of refcount blocks
1876 * note: every host cluster is reference-counted, including metadata
1877 * (even refcount blocks are recursively included).
1879 * a = total_size (this is the guest disk size)
1880 * m = meta size not including refcount blocks and refcount tables
1882 * y1 = number of refcount blocks entries
1883 * y2 = meta size including everything
1884 * rces = refcount entry size in bytes
1887 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m
1889 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c)
1891 nrefblocke
= (aligned_total_size
+ meta_size
+ cluster_size
)
1892 / (cluster_size
- rces
- rces
* sizeof(uint64_t)
1894 meta_size
+= DIV_ROUND_UP(nrefblocke
, refblock_size
) * cluster_size
;
1896 /* total size of refcount tables */
1897 nreftablee
= nrefblocke
/ refblock_size
;
1898 nreftablee
= align_offset(nreftablee
, cluster_size
/ sizeof(uint64_t));
1899 meta_size
+= nreftablee
* sizeof(uint64_t);
1901 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
,
1902 aligned_total_size
+ meta_size
, &error_abort
);
1903 qemu_opt_set(opts
, BLOCK_OPT_PREALLOC
, PreallocMode_lookup
[prealloc
],
1907 ret
= bdrv_create_file(filename
, opts
, &local_err
);
1909 error_propagate(errp
, local_err
);
1914 ret
= bdrv_open(&bs
, filename
, NULL
, NULL
, BDRV_O_RDWR
| BDRV_O_PROTOCOL
,
1917 error_propagate(errp
, local_err
);
1921 /* Write the header */
1922 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS
) < sizeof(*header
));
1923 header
= g_malloc0(cluster_size
);
1924 *header
= (QCowHeader
) {
1925 .magic
= cpu_to_be32(QCOW_MAGIC
),
1926 .version
= cpu_to_be32(version
),
1927 .cluster_bits
= cpu_to_be32(cluster_bits
),
1928 .size
= cpu_to_be64(0),
1929 .l1_table_offset
= cpu_to_be64(0),
1930 .l1_size
= cpu_to_be32(0),
1931 .refcount_table_offset
= cpu_to_be64(cluster_size
),
1932 .refcount_table_clusters
= cpu_to_be32(1),
1933 .refcount_order
= cpu_to_be32(refcount_order
),
1934 .header_length
= cpu_to_be32(sizeof(*header
)),
1937 if (flags
& BLOCK_FLAG_ENCRYPT
) {
1938 header
->crypt_method
= cpu_to_be32(QCOW_CRYPT_AES
);
1940 header
->crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
1943 if (flags
& BLOCK_FLAG_LAZY_REFCOUNTS
) {
1944 header
->compatible_features
|=
1945 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS
);
1948 ret
= bdrv_pwrite(bs
, 0, header
, cluster_size
);
1951 error_setg_errno(errp
, -ret
, "Could not write qcow2 header");
1955 /* Write a refcount table with one refcount block */
1956 refcount_table
= g_malloc0(2 * cluster_size
);
1957 refcount_table
[0] = cpu_to_be64(2 * cluster_size
);
1958 ret
= bdrv_pwrite(bs
, cluster_size
, refcount_table
, 2 * cluster_size
);
1959 g_free(refcount_table
);
1962 error_setg_errno(errp
, -ret
, "Could not write refcount table");
1970 * And now open the image and make it consistent first (i.e. increase the
1971 * refcount of the cluster that is occupied by the header and the refcount
1974 ret
= bdrv_open(&bs
, filename
, NULL
, NULL
,
1975 BDRV_O_RDWR
| BDRV_O_CACHE_WB
| BDRV_O_NO_FLUSH
,
1976 &bdrv_qcow2
, &local_err
);
1978 error_propagate(errp
, local_err
);
1982 ret
= qcow2_alloc_clusters(bs
, 3 * cluster_size
);
1984 error_setg_errno(errp
, -ret
, "Could not allocate clusters for qcow2 "
1985 "header and refcount table");
1988 } else if (ret
!= 0) {
1989 error_report("Huh, first cluster in empty image is already in use?");
1993 /* Okay, now that we have a valid image, let's give it the right size */
1994 ret
= bdrv_truncate(bs
, total_size
);
1996 error_setg_errno(errp
, -ret
, "Could not resize image");
2000 /* Want a backing file? There you go.*/
2002 ret
= bdrv_change_backing_file(bs
, backing_file
, backing_format
);
2004 error_setg_errno(errp
, -ret
, "Could not assign backing file '%s' "
2005 "with format '%s'", backing_file
, backing_format
);
2010 /* And if we're supposed to preallocate metadata, do that now */
2011 if (prealloc
!= PREALLOC_MODE_OFF
) {
2012 BDRVQcowState
*s
= bs
->opaque
;
2013 qemu_co_mutex_lock(&s
->lock
);
2014 ret
= preallocate(bs
);
2015 qemu_co_mutex_unlock(&s
->lock
);
2017 error_setg_errno(errp
, -ret
, "Could not preallocate metadata");
2025 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */
2026 ret
= bdrv_open(&bs
, filename
, NULL
, NULL
,
2027 BDRV_O_RDWR
| BDRV_O_CACHE_WB
| BDRV_O_NO_BACKING
,
2028 &bdrv_qcow2
, &local_err
);
2030 error_propagate(errp
, local_err
);
2042 static int qcow2_create(const char *filename
, QemuOpts
*opts
, Error
**errp
)
2044 char *backing_file
= NULL
;
2045 char *backing_fmt
= NULL
;
2049 size_t cluster_size
= DEFAULT_CLUSTER_SIZE
;
2050 PreallocMode prealloc
;
2052 uint64_t refcount_bits
= 16;
2054 Error
*local_err
= NULL
;
2057 /* Read out options */
2058 size
= ROUND_UP(qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0),
2060 backing_file
= qemu_opt_get_del(opts
, BLOCK_OPT_BACKING_FILE
);
2061 backing_fmt
= qemu_opt_get_del(opts
, BLOCK_OPT_BACKING_FMT
);
2062 if (qemu_opt_get_bool_del(opts
, BLOCK_OPT_ENCRYPT
, false)) {
2063 flags
|= BLOCK_FLAG_ENCRYPT
;
2065 cluster_size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_CLUSTER_SIZE
,
2066 DEFAULT_CLUSTER_SIZE
);
2067 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
2068 prealloc
= qapi_enum_parse(PreallocMode_lookup
, buf
,
2069 PREALLOC_MODE_MAX
, PREALLOC_MODE_OFF
,
2072 error_propagate(errp
, local_err
);
2077 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_COMPAT_LEVEL
);
2079 /* keep the default */
2080 } else if (!strcmp(buf
, "0.10")) {
2082 } else if (!strcmp(buf
, "1.1")) {
2085 error_setg(errp
, "Invalid compatibility level: '%s'", buf
);
2090 if (qemu_opt_get_bool_del(opts
, BLOCK_OPT_LAZY_REFCOUNTS
, false)) {
2091 flags
|= BLOCK_FLAG_LAZY_REFCOUNTS
;
2094 if (backing_file
&& prealloc
!= PREALLOC_MODE_OFF
) {
2095 error_setg(errp
, "Backing file and preallocation cannot be used at "
2101 if (version
< 3 && (flags
& BLOCK_FLAG_LAZY_REFCOUNTS
)) {
2102 error_setg(errp
, "Lazy refcounts only supported with compatibility "
2103 "level 1.1 and above (use compat=1.1 or greater)");
2108 refcount_bits
= qemu_opt_get_number_del(opts
, BLOCK_OPT_REFCOUNT_BITS
,
2110 if (refcount_bits
> 64 || !is_power_of_2(refcount_bits
)) {
2111 error_setg(errp
, "Refcount width must be a power of two and may not "
2117 if (version
< 3 && refcount_bits
!= 16) {
2118 error_setg(errp
, "Different refcount widths than 16 bits require "
2119 "compatibility level 1.1 or above (use compat=1.1 or "
2125 refcount_order
= ctz32(refcount_bits
);
2127 ret
= qcow2_create2(filename
, size
, backing_file
, backing_fmt
, flags
,
2128 cluster_size
, prealloc
, opts
, version
, refcount_order
,
2131 error_propagate(errp
, local_err
);
2135 g_free(backing_file
);
2136 g_free(backing_fmt
);
2141 static coroutine_fn
int qcow2_co_write_zeroes(BlockDriverState
*bs
,
2142 int64_t sector_num
, int nb_sectors
, BdrvRequestFlags flags
)
2145 BDRVQcowState
*s
= bs
->opaque
;
2147 /* Emulate misaligned zero writes */
2148 if (sector_num
% s
->cluster_sectors
|| nb_sectors
% s
->cluster_sectors
) {
2152 /* Whatever is left can use real zero clusters */
2153 qemu_co_mutex_lock(&s
->lock
);
2154 ret
= qcow2_zero_clusters(bs
, sector_num
<< BDRV_SECTOR_BITS
,
2156 qemu_co_mutex_unlock(&s
->lock
);
2161 static coroutine_fn
int qcow2_co_discard(BlockDriverState
*bs
,
2162 int64_t sector_num
, int nb_sectors
)
2165 BDRVQcowState
*s
= bs
->opaque
;
2167 qemu_co_mutex_lock(&s
->lock
);
2168 ret
= qcow2_discard_clusters(bs
, sector_num
<< BDRV_SECTOR_BITS
,
2169 nb_sectors
, QCOW2_DISCARD_REQUEST
, false);
2170 qemu_co_mutex_unlock(&s
->lock
);
2174 static int qcow2_truncate(BlockDriverState
*bs
, int64_t offset
)
2176 BDRVQcowState
*s
= bs
->opaque
;
2177 int64_t new_l1_size
;
2181 error_report("The new size must be a multiple of 512");
2185 /* cannot proceed if image has snapshots */
2186 if (s
->nb_snapshots
) {
2187 error_report("Can't resize an image which has snapshots");
2191 /* shrinking is currently not supported */
2192 if (offset
< bs
->total_sectors
* 512) {
2193 error_report("qcow2 doesn't support shrinking images yet");
2197 new_l1_size
= size_to_l1(s
, offset
);
2198 ret
= qcow2_grow_l1_table(bs
, new_l1_size
, true);
2203 /* write updated header.size */
2204 offset
= cpu_to_be64(offset
);
2205 ret
= bdrv_pwrite_sync(bs
->file
, offsetof(QCowHeader
, size
),
2206 &offset
, sizeof(uint64_t));
2211 s
->l1_vm_state_index
= new_l1_size
;
2215 /* XXX: put compressed sectors first, then all the cluster aligned
2216 tables to avoid losing bytes in alignment */
2217 static int qcow2_write_compressed(BlockDriverState
*bs
, int64_t sector_num
,
2218 const uint8_t *buf
, int nb_sectors
)
2220 BDRVQcowState
*s
= bs
->opaque
;
2224 uint64_t cluster_offset
;
2226 if (nb_sectors
== 0) {
2227 /* align end of file to a sector boundary to ease reading with
2228 sector based I/Os */
2229 cluster_offset
= bdrv_getlength(bs
->file
);
2230 return bdrv_truncate(bs
->file
, cluster_offset
);
2233 if (nb_sectors
!= s
->cluster_sectors
) {
2236 /* Zero-pad last write if image size is not cluster aligned */
2237 if (sector_num
+ nb_sectors
== bs
->total_sectors
&&
2238 nb_sectors
< s
->cluster_sectors
) {
2239 uint8_t *pad_buf
= qemu_blockalign(bs
, s
->cluster_size
);
2240 memset(pad_buf
, 0, s
->cluster_size
);
2241 memcpy(pad_buf
, buf
, nb_sectors
* BDRV_SECTOR_SIZE
);
2242 ret
= qcow2_write_compressed(bs
, sector_num
,
2243 pad_buf
, s
->cluster_sectors
);
2244 qemu_vfree(pad_buf
);
2249 out_buf
= g_malloc(s
->cluster_size
+ (s
->cluster_size
/ 1000) + 128);
2251 /* best compression, small window, no zlib header */
2252 memset(&strm
, 0, sizeof(strm
));
2253 ret
= deflateInit2(&strm
, Z_DEFAULT_COMPRESSION
,
2255 9, Z_DEFAULT_STRATEGY
);
2261 strm
.avail_in
= s
->cluster_size
;
2262 strm
.next_in
= (uint8_t *)buf
;
2263 strm
.avail_out
= s
->cluster_size
;
2264 strm
.next_out
= out_buf
;
2266 ret
= deflate(&strm
, Z_FINISH
);
2267 if (ret
!= Z_STREAM_END
&& ret
!= Z_OK
) {
2272 out_len
= strm
.next_out
- out_buf
;
2276 if (ret
!= Z_STREAM_END
|| out_len
>= s
->cluster_size
) {
2277 /* could not compress: write normal cluster */
2278 ret
= bdrv_write(bs
, sector_num
, buf
, s
->cluster_sectors
);
2283 cluster_offset
= qcow2_alloc_compressed_cluster_offset(bs
,
2284 sector_num
<< 9, out_len
);
2285 if (!cluster_offset
) {
2289 cluster_offset
&= s
->cluster_offset_mask
;
2291 ret
= qcow2_pre_write_overlap_check(bs
, 0, cluster_offset
, out_len
);
2296 BLKDBG_EVENT(bs
->file
, BLKDBG_WRITE_COMPRESSED
);
2297 ret
= bdrv_pwrite(bs
->file
, cluster_offset
, out_buf
, out_len
);
2309 static int make_completely_empty(BlockDriverState
*bs
)
2311 BDRVQcowState
*s
= bs
->opaque
;
2312 int ret
, l1_clusters
;
2314 uint64_t *new_reftable
= NULL
;
2315 uint64_t rt_entry
, l1_size2
;
2318 uint64_t reftable_offset
;
2319 uint32_t reftable_clusters
;
2320 } QEMU_PACKED l1_ofs_rt_ofs_cls
;
2322 ret
= qcow2_cache_empty(bs
, s
->l2_table_cache
);
2327 ret
= qcow2_cache_empty(bs
, s
->refcount_block_cache
);
2332 /* Refcounts will be broken utterly */
2333 ret
= qcow2_mark_dirty(bs
);
2338 BLKDBG_EVENT(bs
->file
, BLKDBG_L1_UPDATE
);
2340 l1_clusters
= DIV_ROUND_UP(s
->l1_size
, s
->cluster_size
/ sizeof(uint64_t));
2341 l1_size2
= (uint64_t)s
->l1_size
* sizeof(uint64_t);
2343 /* After this call, neither the in-memory nor the on-disk refcount
2344 * information accurately describe the actual references */
2346 ret
= bdrv_write_zeroes(bs
->file
, s
->l1_table_offset
/ BDRV_SECTOR_SIZE
,
2347 l1_clusters
* s
->cluster_sectors
, 0);
2349 goto fail_broken_refcounts
;
2351 memset(s
->l1_table
, 0, l1_size2
);
2353 BLKDBG_EVENT(bs
->file
, BLKDBG_EMPTY_IMAGE_PREPARE
);
2355 /* Overwrite enough clusters at the beginning of the sectors to place
2356 * the refcount table, a refcount block and the L1 table in; this may
2357 * overwrite parts of the existing refcount and L1 table, which is not
2358 * an issue because the dirty flag is set, complete data loss is in fact
2359 * desired and partial data loss is consequently fine as well */
2360 ret
= bdrv_write_zeroes(bs
->file
, s
->cluster_size
/ BDRV_SECTOR_SIZE
,
2361 (2 + l1_clusters
) * s
->cluster_size
/
2362 BDRV_SECTOR_SIZE
, 0);
2363 /* This call (even if it failed overall) may have overwritten on-disk
2364 * refcount structures; in that case, the in-memory refcount information
2365 * will probably differ from the on-disk information which makes the BDS
2368 goto fail_broken_refcounts
;
2371 BLKDBG_EVENT(bs
->file
, BLKDBG_L1_UPDATE
);
2372 BLKDBG_EVENT(bs
->file
, BLKDBG_REFTABLE_UPDATE
);
2374 /* "Create" an empty reftable (one cluster) directly after the image
2375 * header and an empty L1 table three clusters after the image header;
2376 * the cluster between those two will be used as the first refblock */
2377 cpu_to_be64w(&l1_ofs_rt_ofs_cls
.l1_offset
, 3 * s
->cluster_size
);
2378 cpu_to_be64w(&l1_ofs_rt_ofs_cls
.reftable_offset
, s
->cluster_size
);
2379 cpu_to_be32w(&l1_ofs_rt_ofs_cls
.reftable_clusters
, 1);
2380 ret
= bdrv_pwrite_sync(bs
->file
, offsetof(QCowHeader
, l1_table_offset
),
2381 &l1_ofs_rt_ofs_cls
, sizeof(l1_ofs_rt_ofs_cls
));
2383 goto fail_broken_refcounts
;
2386 s
->l1_table_offset
= 3 * s
->cluster_size
;
2388 new_reftable
= g_try_new0(uint64_t, s
->cluster_size
/ sizeof(uint64_t));
2389 if (!new_reftable
) {
2391 goto fail_broken_refcounts
;
2394 s
->refcount_table_offset
= s
->cluster_size
;
2395 s
->refcount_table_size
= s
->cluster_size
/ sizeof(uint64_t);
2397 g_free(s
->refcount_table
);
2398 s
->refcount_table
= new_reftable
;
2399 new_reftable
= NULL
;
2401 /* Now the in-memory refcount information again corresponds to the on-disk
2402 * information (reftable is empty and no refblocks (the refblock cache is
2403 * empty)); however, this means some clusters (e.g. the image header) are
2404 * referenced, but not refcounted, but the normal qcow2 code assumes that
2405 * the in-memory information is always correct */
2407 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_ALLOC
);
2409 /* Enter the first refblock into the reftable */
2410 rt_entry
= cpu_to_be64(2 * s
->cluster_size
);
2411 ret
= bdrv_pwrite_sync(bs
->file
, s
->cluster_size
,
2412 &rt_entry
, sizeof(rt_entry
));
2414 goto fail_broken_refcounts
;
2416 s
->refcount_table
[0] = 2 * s
->cluster_size
;
2418 s
->free_cluster_index
= 0;
2419 assert(3 + l1_clusters
<= s
->refcount_block_size
);
2420 offset
= qcow2_alloc_clusters(bs
, 3 * s
->cluster_size
+ l1_size2
);
2423 goto fail_broken_refcounts
;
2424 } else if (offset
> 0) {
2425 error_report("First cluster in emptied image is in use");
2429 /* Now finally the in-memory information corresponds to the on-disk
2430 * structures and is correct */
2431 ret
= qcow2_mark_clean(bs
);
2436 ret
= bdrv_truncate(bs
->file
, (3 + l1_clusters
) * s
->cluster_size
);
2443 fail_broken_refcounts
:
2444 /* The BDS is unusable at this point. If we wanted to make it usable, we
2445 * would have to call qcow2_refcount_close(), qcow2_refcount_init(),
2446 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
2447 * again. However, because the functions which could have caused this error
2448 * path to be taken are used by those functions as well, it's very likely
2449 * that that sequence will fail as well. Therefore, just eject the BDS. */
2453 g_free(new_reftable
);
2457 static int qcow2_make_empty(BlockDriverState
*bs
)
2459 BDRVQcowState
*s
= bs
->opaque
;
2460 uint64_t start_sector
;
2461 int sector_step
= INT_MAX
/ BDRV_SECTOR_SIZE
;
2462 int l1_clusters
, ret
= 0;
2464 l1_clusters
= DIV_ROUND_UP(s
->l1_size
, s
->cluster_size
/ sizeof(uint64_t));
2466 if (s
->qcow_version
>= 3 && !s
->snapshots
&&
2467 3 + l1_clusters
<= s
->refcount_block_size
) {
2468 /* The following function only works for qcow2 v3 images (it requires
2469 * the dirty flag) and only as long as there are no snapshots (because
2470 * it completely empties the image). Furthermore, the L1 table and three
2471 * additional clusters (image header, refcount table, one refcount
2472 * block) have to fit inside one refcount block. */
2473 return make_completely_empty(bs
);
2476 /* This fallback code simply discards every active cluster; this is slow,
2477 * but works in all cases */
2478 for (start_sector
= 0; start_sector
< bs
->total_sectors
;
2479 start_sector
+= sector_step
)
2481 /* As this function is generally used after committing an external
2482 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
2483 * default action for this kind of discard is to pass the discard,
2484 * which will ideally result in an actually smaller image file, as
2485 * is probably desired. */
2486 ret
= qcow2_discard_clusters(bs
, start_sector
* BDRV_SECTOR_SIZE
,
2488 bs
->total_sectors
- start_sector
),
2489 QCOW2_DISCARD_SNAPSHOT
, true);
2498 static coroutine_fn
int qcow2_co_flush_to_os(BlockDriverState
*bs
)
2500 BDRVQcowState
*s
= bs
->opaque
;
2503 qemu_co_mutex_lock(&s
->lock
);
2504 ret
= qcow2_cache_flush(bs
, s
->l2_table_cache
);
2506 qemu_co_mutex_unlock(&s
->lock
);
2510 if (qcow2_need_accurate_refcounts(s
)) {
2511 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
2513 qemu_co_mutex_unlock(&s
->lock
);
2517 qemu_co_mutex_unlock(&s
->lock
);
2522 static int qcow2_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
2524 BDRVQcowState
*s
= bs
->opaque
;
2525 bdi
->unallocated_blocks_are_zero
= true;
2526 bdi
->can_write_zeroes_with_unmap
= (s
->qcow_version
>= 3);
2527 bdi
->cluster_size
= s
->cluster_size
;
2528 bdi
->vm_state_offset
= qcow2_vm_state_offset(s
);
2532 static ImageInfoSpecific
*qcow2_get_specific_info(BlockDriverState
*bs
)
2534 BDRVQcowState
*s
= bs
->opaque
;
2535 ImageInfoSpecific
*spec_info
= g_new(ImageInfoSpecific
, 1);
2537 *spec_info
= (ImageInfoSpecific
){
2538 .kind
= IMAGE_INFO_SPECIFIC_KIND_QCOW2
,
2540 .qcow2
= g_new(ImageInfoSpecificQCow2
, 1),
2543 if (s
->qcow_version
== 2) {
2544 *spec_info
->qcow2
= (ImageInfoSpecificQCow2
){
2545 .compat
= g_strdup("0.10"),
2546 .refcount_bits
= s
->refcount_bits
,
2548 } else if (s
->qcow_version
== 3) {
2549 *spec_info
->qcow2
= (ImageInfoSpecificQCow2
){
2550 .compat
= g_strdup("1.1"),
2551 .lazy_refcounts
= s
->compatible_features
&
2552 QCOW2_COMPAT_LAZY_REFCOUNTS
,
2553 .has_lazy_refcounts
= true,
2554 .corrupt
= s
->incompatible_features
&
2555 QCOW2_INCOMPAT_CORRUPT
,
2556 .has_corrupt
= true,
2557 .refcount_bits
= s
->refcount_bits
,
2565 static void dump_refcounts(BlockDriverState
*bs
)
2567 BDRVQcowState
*s
= bs
->opaque
;
2568 int64_t nb_clusters
, k
, k1
, size
;
2571 size
= bdrv_getlength(bs
->file
);
2572 nb_clusters
= size_to_clusters(s
, size
);
2573 for(k
= 0; k
< nb_clusters
;) {
2575 refcount
= get_refcount(bs
, k
);
2577 while (k
< nb_clusters
&& get_refcount(bs
, k
) == refcount
)
2579 printf("%" PRId64
": refcount=%d nb=%" PRId64
"\n", k
, refcount
,
2585 static int qcow2_save_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
2588 BDRVQcowState
*s
= bs
->opaque
;
2589 int64_t total_sectors
= bs
->total_sectors
;
2590 bool zero_beyond_eof
= bs
->zero_beyond_eof
;
2593 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_SAVE
);
2594 bs
->zero_beyond_eof
= false;
2595 ret
= bdrv_pwritev(bs
, qcow2_vm_state_offset(s
) + pos
, qiov
);
2596 bs
->zero_beyond_eof
= zero_beyond_eof
;
2598 /* bdrv_co_do_writev will have increased the total_sectors value to include
2599 * the VM state - the VM state is however not an actual part of the block
2600 * device, therefore, we need to restore the old value. */
2601 bs
->total_sectors
= total_sectors
;
2606 static int qcow2_load_vmstate(BlockDriverState
*bs
, uint8_t *buf
,
2607 int64_t pos
, int size
)
2609 BDRVQcowState
*s
= bs
->opaque
;
2610 bool zero_beyond_eof
= bs
->zero_beyond_eof
;
2613 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_LOAD
);
2614 bs
->zero_beyond_eof
= false;
2615 ret
= bdrv_pread(bs
, qcow2_vm_state_offset(s
) + pos
, buf
, size
);
2616 bs
->zero_beyond_eof
= zero_beyond_eof
;
2622 * Downgrades an image's version. To achieve this, any incompatible features
2623 * have to be removed.
2625 static int qcow2_downgrade(BlockDriverState
*bs
, int target_version
,
2626 BlockDriverAmendStatusCB
*status_cb
)
2628 BDRVQcowState
*s
= bs
->opaque
;
2629 int current_version
= s
->qcow_version
;
2632 if (target_version
== current_version
) {
2634 } else if (target_version
> current_version
) {
2636 } else if (target_version
!= 2) {
2640 if (s
->refcount_order
!= 4) {
2641 /* we would have to convert the image to a refcount_order == 4 image
2642 * here; however, since qemu (at the time of writing this) does not
2643 * support anything different than 4 anyway, there is no point in doing
2644 * so right now; however, we should error out (if qemu supports this in
2645 * the future and this code has not been adapted) */
2646 error_report("qcow2_downgrade: Image refcount orders other than 4 are "
2647 "currently not supported.");
2651 /* clear incompatible features */
2652 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
2653 ret
= qcow2_mark_clean(bs
);
2659 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
2660 * the first place; if that happens nonetheless, returning -ENOTSUP is the
2661 * best thing to do anyway */
2663 if (s
->incompatible_features
) {
2667 /* since we can ignore compatible features, we can set them to 0 as well */
2668 s
->compatible_features
= 0;
2669 /* if lazy refcounts have been used, they have already been fixed through
2670 * clearing the dirty flag */
2672 /* clearing autoclear features is trivial */
2673 s
->autoclear_features
= 0;
2675 ret
= qcow2_expand_zero_clusters(bs
, status_cb
);
2680 s
->qcow_version
= target_version
;
2681 ret
= qcow2_update_header(bs
);
2683 s
->qcow_version
= current_version
;
2689 static int qcow2_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
,
2690 BlockDriverAmendStatusCB
*status_cb
)
2692 BDRVQcowState
*s
= bs
->opaque
;
2693 int old_version
= s
->qcow_version
, new_version
= old_version
;
2694 uint64_t new_size
= 0;
2695 const char *backing_file
= NULL
, *backing_format
= NULL
;
2696 bool lazy_refcounts
= s
->use_lazy_refcounts
;
2697 const char *compat
= NULL
;
2698 uint64_t cluster_size
= s
->cluster_size
;
2701 QemuOptDesc
*desc
= opts
->list
->desc
;
2703 while (desc
&& desc
->name
) {
2704 if (!qemu_opt_find(opts
, desc
->name
)) {
2705 /* only change explicitly defined options */
2710 if (!strcmp(desc
->name
, BLOCK_OPT_COMPAT_LEVEL
)) {
2711 compat
= qemu_opt_get(opts
, BLOCK_OPT_COMPAT_LEVEL
);
2713 /* preserve default */
2714 } else if (!strcmp(compat
, "0.10")) {
2716 } else if (!strcmp(compat
, "1.1")) {
2719 fprintf(stderr
, "Unknown compatibility level %s.\n", compat
);
2722 } else if (!strcmp(desc
->name
, BLOCK_OPT_PREALLOC
)) {
2723 fprintf(stderr
, "Cannot change preallocation mode.\n");
2725 } else if (!strcmp(desc
->name
, BLOCK_OPT_SIZE
)) {
2726 new_size
= qemu_opt_get_size(opts
, BLOCK_OPT_SIZE
, 0);
2727 } else if (!strcmp(desc
->name
, BLOCK_OPT_BACKING_FILE
)) {
2728 backing_file
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FILE
);
2729 } else if (!strcmp(desc
->name
, BLOCK_OPT_BACKING_FMT
)) {
2730 backing_format
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FMT
);
2731 } else if (!strcmp(desc
->name
, BLOCK_OPT_ENCRYPT
)) {
2732 encrypt
= qemu_opt_get_bool(opts
, BLOCK_OPT_ENCRYPT
,
2735 if (encrypt
!= !!s
->cipher
) {
2736 fprintf(stderr
, "Changing the encryption flag is not "
2740 } else if (!strcmp(desc
->name
, BLOCK_OPT_CLUSTER_SIZE
)) {
2741 cluster_size
= qemu_opt_get_size(opts
, BLOCK_OPT_CLUSTER_SIZE
,
2743 if (cluster_size
!= s
->cluster_size
) {
2744 fprintf(stderr
, "Changing the cluster size is not "
2748 } else if (!strcmp(desc
->name
, BLOCK_OPT_LAZY_REFCOUNTS
)) {
2749 lazy_refcounts
= qemu_opt_get_bool(opts
, BLOCK_OPT_LAZY_REFCOUNTS
,
2751 } else if (!strcmp(desc
->name
, BLOCK_OPT_REFCOUNT_BITS
)) {
2752 error_report("Cannot change refcount entry width");
2755 /* if this assertion fails, this probably means a new option was
2756 * added without having it covered here */
2763 if (new_version
!= old_version
) {
2764 if (new_version
> old_version
) {
2766 s
->qcow_version
= new_version
;
2767 ret
= qcow2_update_header(bs
);
2769 s
->qcow_version
= old_version
;
2773 ret
= qcow2_downgrade(bs
, new_version
, status_cb
);
2780 if (backing_file
|| backing_format
) {
2781 ret
= qcow2_change_backing_file(bs
,
2782 backing_file
?: s
->image_backing_file
,
2783 backing_format
?: s
->image_backing_format
);
2789 if (s
->use_lazy_refcounts
!= lazy_refcounts
) {
2790 if (lazy_refcounts
) {
2791 if (s
->qcow_version
< 3) {
2792 fprintf(stderr
, "Lazy refcounts only supported with compatibility "
2793 "level 1.1 and above (use compat=1.1 or greater)\n");
2796 s
->compatible_features
|= QCOW2_COMPAT_LAZY_REFCOUNTS
;
2797 ret
= qcow2_update_header(bs
);
2799 s
->compatible_features
&= ~QCOW2_COMPAT_LAZY_REFCOUNTS
;
2802 s
->use_lazy_refcounts
= true;
2804 /* make image clean first */
2805 ret
= qcow2_mark_clean(bs
);
2809 /* now disallow lazy refcounts */
2810 s
->compatible_features
&= ~QCOW2_COMPAT_LAZY_REFCOUNTS
;
2811 ret
= qcow2_update_header(bs
);
2813 s
->compatible_features
|= QCOW2_COMPAT_LAZY_REFCOUNTS
;
2816 s
->use_lazy_refcounts
= false;
2821 ret
= bdrv_truncate(bs
, new_size
);
2831 * If offset or size are negative, respectively, they will not be included in
2832 * the BLOCK_IMAGE_CORRUPTED event emitted.
2833 * fatal will be ignored for read-only BDS; corruptions found there will always
2834 * be considered non-fatal.
2836 void qcow2_signal_corruption(BlockDriverState
*bs
, bool fatal
, int64_t offset
,
2837 int64_t size
, const char *message_format
, ...)
2839 BDRVQcowState
*s
= bs
->opaque
;
2840 const char *node_name
;
2844 fatal
= fatal
&& !bs
->read_only
;
2846 if (s
->signaled_corruption
&&
2847 (!fatal
|| (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
)))
2852 va_start(ap
, message_format
);
2853 message
= g_strdup_vprintf(message_format
, ap
);
2857 fprintf(stderr
, "qcow2: Marking image as corrupt: %s; further "
2858 "corruption events will be suppressed\n", message
);
2860 fprintf(stderr
, "qcow2: Image is corrupt: %s; further non-fatal "
2861 "corruption events will be suppressed\n", message
);
2864 node_name
= bdrv_get_node_name(bs
);
2865 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs
),
2866 *node_name
!= '\0', node_name
,
2867 message
, offset
>= 0, offset
,
2869 fatal
, &error_abort
);
2873 qcow2_mark_corrupt(bs
);
2874 bs
->drv
= NULL
; /* make BDS unusable */
2877 s
->signaled_corruption
= true;
2880 static QemuOptsList qcow2_create_opts
= {
2881 .name
= "qcow2-create-opts",
2882 .head
= QTAILQ_HEAD_INITIALIZER(qcow2_create_opts
.head
),
2885 .name
= BLOCK_OPT_SIZE
,
2886 .type
= QEMU_OPT_SIZE
,
2887 .help
= "Virtual disk size"
2890 .name
= BLOCK_OPT_COMPAT_LEVEL
,
2891 .type
= QEMU_OPT_STRING
,
2892 .help
= "Compatibility level (0.10 or 1.1)"
2895 .name
= BLOCK_OPT_BACKING_FILE
,
2896 .type
= QEMU_OPT_STRING
,
2897 .help
= "File name of a base image"
2900 .name
= BLOCK_OPT_BACKING_FMT
,
2901 .type
= QEMU_OPT_STRING
,
2902 .help
= "Image format of the base image"
2905 .name
= BLOCK_OPT_ENCRYPT
,
2906 .type
= QEMU_OPT_BOOL
,
2907 .help
= "Encrypt the image",
2908 .def_value_str
= "off"
2911 .name
= BLOCK_OPT_CLUSTER_SIZE
,
2912 .type
= QEMU_OPT_SIZE
,
2913 .help
= "qcow2 cluster size",
2914 .def_value_str
= stringify(DEFAULT_CLUSTER_SIZE
)
2917 .name
= BLOCK_OPT_PREALLOC
,
2918 .type
= QEMU_OPT_STRING
,
2919 .help
= "Preallocation mode (allowed values: off, metadata, "
2923 .name
= BLOCK_OPT_LAZY_REFCOUNTS
,
2924 .type
= QEMU_OPT_BOOL
,
2925 .help
= "Postpone refcount updates",
2926 .def_value_str
= "off"
2929 .name
= BLOCK_OPT_REFCOUNT_BITS
,
2930 .type
= QEMU_OPT_NUMBER
,
2931 .help
= "Width of a reference count entry in bits",
2932 .def_value_str
= "16"
2934 { /* end of list */ }
2938 BlockDriver bdrv_qcow2
= {
2939 .format_name
= "qcow2",
2940 .instance_size
= sizeof(BDRVQcowState
),
2941 .bdrv_probe
= qcow2_probe
,
2942 .bdrv_open
= qcow2_open
,
2943 .bdrv_close
= qcow2_close
,
2944 .bdrv_reopen_prepare
= qcow2_reopen_prepare
,
2945 .bdrv_create
= qcow2_create
,
2946 .bdrv_has_zero_init
= bdrv_has_zero_init_1
,
2947 .bdrv_co_get_block_status
= qcow2_co_get_block_status
,
2948 .bdrv_set_key
= qcow2_set_key
,
2950 .bdrv_co_readv
= qcow2_co_readv
,
2951 .bdrv_co_writev
= qcow2_co_writev
,
2952 .bdrv_co_flush_to_os
= qcow2_co_flush_to_os
,
2954 .bdrv_co_write_zeroes
= qcow2_co_write_zeroes
,
2955 .bdrv_co_discard
= qcow2_co_discard
,
2956 .bdrv_truncate
= qcow2_truncate
,
2957 .bdrv_write_compressed
= qcow2_write_compressed
,
2958 .bdrv_make_empty
= qcow2_make_empty
,
2960 .bdrv_snapshot_create
= qcow2_snapshot_create
,
2961 .bdrv_snapshot_goto
= qcow2_snapshot_goto
,
2962 .bdrv_snapshot_delete
= qcow2_snapshot_delete
,
2963 .bdrv_snapshot_list
= qcow2_snapshot_list
,
2964 .bdrv_snapshot_load_tmp
= qcow2_snapshot_load_tmp
,
2965 .bdrv_get_info
= qcow2_get_info
,
2966 .bdrv_get_specific_info
= qcow2_get_specific_info
,
2968 .bdrv_save_vmstate
= qcow2_save_vmstate
,
2969 .bdrv_load_vmstate
= qcow2_load_vmstate
,
2971 .supports_backing
= true,
2972 .bdrv_change_backing_file
= qcow2_change_backing_file
,
2974 .bdrv_refresh_limits
= qcow2_refresh_limits
,
2975 .bdrv_invalidate_cache
= qcow2_invalidate_cache
,
2977 .create_opts
= &qcow2_create_opts
,
2978 .bdrv_check
= qcow2_check
,
2979 .bdrv_amend_options
= qcow2_amend_options
,
2982 static void bdrv_qcow2_init(void)
2984 bdrv_register(&bdrv_qcow2
);
2987 block_init(bdrv_qcow2_init
);