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"
29 #include "block/qcow2.h"
30 #include "qemu/error-report.h"
31 #include "qapi/qmp/qerror.h"
32 #include "qapi/qmp/qbool.h"
34 #include "qemu/option_int.h"
37 Differences with QCOW:
39 - Support for multiple incremental snapshots.
40 - Memory management by reference counts.
41 - Clusters which have a reference count of one have the bit
42 QCOW_OFLAG_COPIED to optimize write performance.
43 - Size of compressed clusters is stored in sectors to reduce bit usage
44 in the cluster offsets.
45 - Support for storing additional data (such as the VM state) in the
47 - If a backing store is used, the cluster size is not constrained
48 (could be backported to QCOW).
49 - L2 tables have always a size of one cluster.
56 } QEMU_PACKED QCowExtension
;
58 #define QCOW2_EXT_MAGIC_END 0
59 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
60 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
62 static int qcow2_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
64 const QCowHeader
*cow_header
= (const void *)buf
;
66 if (buf_size
>= sizeof(QCowHeader
) &&
67 be32_to_cpu(cow_header
->magic
) == QCOW_MAGIC
&&
68 be32_to_cpu(cow_header
->version
) >= 2)
76 * read qcow2 extension and fill bs
77 * start reading from start_offset
78 * finish reading upon magic of value 0 or when end_offset reached
79 * unknown magic is skipped (future extension this version knows nothing about)
80 * return 0 upon success, non-0 otherwise
82 static int qcow2_read_extensions(BlockDriverState
*bs
, uint64_t start_offset
,
83 uint64_t end_offset
, void **p_feature_table
,
86 BDRVQcowState
*s
= bs
->opaque
;
92 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset
, end_offset
);
94 offset
= start_offset
;
95 while (offset
< end_offset
) {
99 if (offset
> s
->cluster_size
)
100 printf("qcow2_read_extension: suspicious offset %lu\n", offset
);
102 printf("attempting to read extended header in offset %lu\n", offset
);
105 ret
= bdrv_pread(bs
->file
, offset
, &ext
, sizeof(ext
));
107 error_setg_errno(errp
, -ret
, "qcow2_read_extension: ERROR: "
108 "pread fail from offset %" PRIu64
, offset
);
111 be32_to_cpus(&ext
.magic
);
112 be32_to_cpus(&ext
.len
);
113 offset
+= sizeof(ext
);
115 printf("ext.magic = 0x%x\n", ext
.magic
);
117 if (ext
.len
> end_offset
- offset
) {
118 error_setg(errp
, "Header extension too large");
123 case QCOW2_EXT_MAGIC_END
:
126 case QCOW2_EXT_MAGIC_BACKING_FORMAT
:
127 if (ext
.len
>= sizeof(bs
->backing_format
)) {
128 error_setg(errp
, "ERROR: ext_backing_format: len=%" PRIu32
129 " too large (>=%zu)", ext
.len
,
130 sizeof(bs
->backing_format
));
133 ret
= bdrv_pread(bs
->file
, offset
, bs
->backing_format
, ext
.len
);
135 error_setg_errno(errp
, -ret
, "ERROR: ext_backing_format: "
136 "Could not read format name");
139 bs
->backing_format
[ext
.len
] = '\0';
141 printf("Qcow2: Got format extension %s\n", bs
->backing_format
);
145 case QCOW2_EXT_MAGIC_FEATURE_TABLE
:
146 if (p_feature_table
!= NULL
) {
147 void* feature_table
= g_malloc0(ext
.len
+ 2 * sizeof(Qcow2Feature
));
148 ret
= bdrv_pread(bs
->file
, offset
, feature_table
, ext
.len
);
150 error_setg_errno(errp
, -ret
, "ERROR: ext_feature_table: "
151 "Could not read table");
155 *p_feature_table
= feature_table
;
160 /* unknown magic - save it in case we need to rewrite the header */
162 Qcow2UnknownHeaderExtension
*uext
;
164 uext
= g_malloc0(sizeof(*uext
) + ext
.len
);
165 uext
->magic
= ext
.magic
;
167 QLIST_INSERT_HEAD(&s
->unknown_header_ext
, uext
, next
);
169 ret
= bdrv_pread(bs
->file
, offset
, uext
->data
, uext
->len
);
171 error_setg_errno(errp
, -ret
, "ERROR: unknown extension: "
172 "Could not read data");
179 offset
+= ((ext
.len
+ 7) & ~7);
185 static void cleanup_unknown_header_ext(BlockDriverState
*bs
)
187 BDRVQcowState
*s
= bs
->opaque
;
188 Qcow2UnknownHeaderExtension
*uext
, *next
;
190 QLIST_FOREACH_SAFE(uext
, &s
->unknown_header_ext
, next
, next
) {
191 QLIST_REMOVE(uext
, next
);
196 static void GCC_FMT_ATTR(3, 4) report_unsupported(BlockDriverState
*bs
,
197 Error
**errp
, const char *fmt
, ...)
203 vsnprintf(msg
, sizeof(msg
), fmt
, ap
);
206 error_set(errp
, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE
, bs
->device_name
, "qcow2",
210 static void report_unsupported_feature(BlockDriverState
*bs
,
211 Error
**errp
, Qcow2Feature
*table
, uint64_t mask
)
213 while (table
&& table
->name
[0] != '\0') {
214 if (table
->type
== QCOW2_FEAT_TYPE_INCOMPATIBLE
) {
215 if (mask
& (1 << table
->bit
)) {
216 report_unsupported(bs
, errp
, "%.46s", table
->name
);
217 mask
&= ~(1 << table
->bit
);
224 report_unsupported(bs
, errp
, "Unknown incompatible feature: %" PRIx64
,
230 * Sets the dirty bit and flushes afterwards if necessary.
232 * The incompatible_features bit is only set if the image file header was
233 * updated successfully. Therefore it is not required to check the return
234 * value of this function.
236 int qcow2_mark_dirty(BlockDriverState
*bs
)
238 BDRVQcowState
*s
= bs
->opaque
;
242 assert(s
->qcow_version
>= 3);
244 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
245 return 0; /* already dirty */
248 val
= cpu_to_be64(s
->incompatible_features
| QCOW2_INCOMPAT_DIRTY
);
249 ret
= bdrv_pwrite(bs
->file
, offsetof(QCowHeader
, incompatible_features
),
254 ret
= bdrv_flush(bs
->file
);
259 /* Only treat image as dirty if the header was updated successfully */
260 s
->incompatible_features
|= QCOW2_INCOMPAT_DIRTY
;
265 * Clears the dirty bit and flushes before if necessary. Only call this
266 * function when there are no pending requests, it does not guard against
267 * concurrent requests dirtying the image.
269 static int qcow2_mark_clean(BlockDriverState
*bs
)
271 BDRVQcowState
*s
= bs
->opaque
;
273 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
276 s
->incompatible_features
&= ~QCOW2_INCOMPAT_DIRTY
;
278 ret
= bdrv_flush(bs
);
283 return qcow2_update_header(bs
);
289 * Marks the image as corrupt.
291 int qcow2_mark_corrupt(BlockDriverState
*bs
)
293 BDRVQcowState
*s
= bs
->opaque
;
295 s
->incompatible_features
|= QCOW2_INCOMPAT_CORRUPT
;
296 return qcow2_update_header(bs
);
300 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
301 * before if necessary.
303 int qcow2_mark_consistent(BlockDriverState
*bs
)
305 BDRVQcowState
*s
= bs
->opaque
;
307 if (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
) {
308 int ret
= bdrv_flush(bs
);
313 s
->incompatible_features
&= ~QCOW2_INCOMPAT_CORRUPT
;
314 return qcow2_update_header(bs
);
319 static int qcow2_check(BlockDriverState
*bs
, BdrvCheckResult
*result
,
322 int ret
= qcow2_check_refcounts(bs
, result
, fix
);
327 if (fix
&& result
->check_errors
== 0 && result
->corruptions
== 0) {
328 ret
= qcow2_mark_clean(bs
);
332 return qcow2_mark_consistent(bs
);
337 static int validate_table_offset(BlockDriverState
*bs
, uint64_t offset
,
338 uint64_t entries
, size_t entry_len
)
340 BDRVQcowState
*s
= bs
->opaque
;
343 /* Use signed INT64_MAX as the maximum even for uint64_t header fields,
344 * because values will be passed to qemu functions taking int64_t. */
345 if (entries
> INT64_MAX
/ entry_len
) {
349 size
= entries
* entry_len
;
351 if (INT64_MAX
- size
< offset
) {
355 /* Tables must be cluster aligned */
356 if (offset
& (s
->cluster_size
- 1)) {
363 static QemuOptsList qcow2_runtime_opts
= {
365 .head
= QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts
.head
),
368 .name
= QCOW2_OPT_LAZY_REFCOUNTS
,
369 .type
= QEMU_OPT_BOOL
,
370 .help
= "Postpone refcount updates",
373 .name
= QCOW2_OPT_DISCARD_REQUEST
,
374 .type
= QEMU_OPT_BOOL
,
375 .help
= "Pass guest discard requests to the layer below",
378 .name
= QCOW2_OPT_DISCARD_SNAPSHOT
,
379 .type
= QEMU_OPT_BOOL
,
380 .help
= "Generate discard requests when snapshot related space "
384 .name
= QCOW2_OPT_DISCARD_OTHER
,
385 .type
= QEMU_OPT_BOOL
,
386 .help
= "Generate discard requests when other clusters are freed",
389 .name
= QCOW2_OPT_OVERLAP
,
390 .type
= QEMU_OPT_STRING
,
391 .help
= "Selects which overlap checks to perform from a range of "
392 "templates (none, constant, cached, all)",
395 .name
= QCOW2_OPT_OVERLAP_MAIN_HEADER
,
396 .type
= QEMU_OPT_BOOL
,
397 .help
= "Check for unintended writes into the main qcow2 header",
400 .name
= QCOW2_OPT_OVERLAP_ACTIVE_L1
,
401 .type
= QEMU_OPT_BOOL
,
402 .help
= "Check for unintended writes into the active L1 table",
405 .name
= QCOW2_OPT_OVERLAP_ACTIVE_L2
,
406 .type
= QEMU_OPT_BOOL
,
407 .help
= "Check for unintended writes into an active L2 table",
410 .name
= QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
,
411 .type
= QEMU_OPT_BOOL
,
412 .help
= "Check for unintended writes into the refcount table",
415 .name
= QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
,
416 .type
= QEMU_OPT_BOOL
,
417 .help
= "Check for unintended writes into a refcount block",
420 .name
= QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
,
421 .type
= QEMU_OPT_BOOL
,
422 .help
= "Check for unintended writes into the snapshot table",
425 .name
= QCOW2_OPT_OVERLAP_INACTIVE_L1
,
426 .type
= QEMU_OPT_BOOL
,
427 .help
= "Check for unintended writes into an inactive L1 table",
430 .name
= QCOW2_OPT_OVERLAP_INACTIVE_L2
,
431 .type
= QEMU_OPT_BOOL
,
432 .help
= "Check for unintended writes into an inactive L2 table",
434 { /* end of list */ }
438 static const char *overlap_bool_option_names
[QCOW2_OL_MAX_BITNR
] = {
439 [QCOW2_OL_MAIN_HEADER_BITNR
] = QCOW2_OPT_OVERLAP_MAIN_HEADER
,
440 [QCOW2_OL_ACTIVE_L1_BITNR
] = QCOW2_OPT_OVERLAP_ACTIVE_L1
,
441 [QCOW2_OL_ACTIVE_L2_BITNR
] = QCOW2_OPT_OVERLAP_ACTIVE_L2
,
442 [QCOW2_OL_REFCOUNT_TABLE_BITNR
] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE
,
443 [QCOW2_OL_REFCOUNT_BLOCK_BITNR
] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK
,
444 [QCOW2_OL_SNAPSHOT_TABLE_BITNR
] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE
,
445 [QCOW2_OL_INACTIVE_L1_BITNR
] = QCOW2_OPT_OVERLAP_INACTIVE_L1
,
446 [QCOW2_OL_INACTIVE_L2_BITNR
] = QCOW2_OPT_OVERLAP_INACTIVE_L2
,
449 static int qcow2_open(BlockDriverState
*bs
, QDict
*options
, int flags
,
452 BDRVQcowState
*s
= bs
->opaque
;
457 Error
*local_err
= NULL
;
459 uint64_t l1_vm_state_index
;
460 const char *opt_overlap_check
;
461 int overlap_check_template
= 0;
463 ret
= bdrv_pread(bs
->file
, 0, &header
, sizeof(header
));
465 error_setg_errno(errp
, -ret
, "Could not read qcow2 header");
468 be32_to_cpus(&header
.magic
);
469 be32_to_cpus(&header
.version
);
470 be64_to_cpus(&header
.backing_file_offset
);
471 be32_to_cpus(&header
.backing_file_size
);
472 be64_to_cpus(&header
.size
);
473 be32_to_cpus(&header
.cluster_bits
);
474 be32_to_cpus(&header
.crypt_method
);
475 be64_to_cpus(&header
.l1_table_offset
);
476 be32_to_cpus(&header
.l1_size
);
477 be64_to_cpus(&header
.refcount_table_offset
);
478 be32_to_cpus(&header
.refcount_table_clusters
);
479 be64_to_cpus(&header
.snapshots_offset
);
480 be32_to_cpus(&header
.nb_snapshots
);
482 if (header
.magic
!= QCOW_MAGIC
) {
483 error_setg(errp
, "Image is not in qcow2 format");
487 if (header
.version
< 2 || header
.version
> 3) {
488 report_unsupported(bs
, errp
, "QCOW version %" PRIu32
, header
.version
);
493 s
->qcow_version
= header
.version
;
495 /* Initialise cluster size */
496 if (header
.cluster_bits
< MIN_CLUSTER_BITS
||
497 header
.cluster_bits
> MAX_CLUSTER_BITS
) {
498 error_setg(errp
, "Unsupported cluster size: 2^%" PRIu32
,
499 header
.cluster_bits
);
504 s
->cluster_bits
= header
.cluster_bits
;
505 s
->cluster_size
= 1 << s
->cluster_bits
;
506 s
->cluster_sectors
= 1 << (s
->cluster_bits
- 9);
508 /* Initialise version 3 header fields */
509 if (header
.version
== 2) {
510 header
.incompatible_features
= 0;
511 header
.compatible_features
= 0;
512 header
.autoclear_features
= 0;
513 header
.refcount_order
= 4;
514 header
.header_length
= 72;
516 be64_to_cpus(&header
.incompatible_features
);
517 be64_to_cpus(&header
.compatible_features
);
518 be64_to_cpus(&header
.autoclear_features
);
519 be32_to_cpus(&header
.refcount_order
);
520 be32_to_cpus(&header
.header_length
);
522 if (header
.header_length
< 104) {
523 error_setg(errp
, "qcow2 header too short");
529 if (header
.header_length
> s
->cluster_size
) {
530 error_setg(errp
, "qcow2 header exceeds cluster size");
535 if (header
.header_length
> sizeof(header
)) {
536 s
->unknown_header_fields_size
= header
.header_length
- sizeof(header
);
537 s
->unknown_header_fields
= g_malloc(s
->unknown_header_fields_size
);
538 ret
= bdrv_pread(bs
->file
, sizeof(header
), s
->unknown_header_fields
,
539 s
->unknown_header_fields_size
);
541 error_setg_errno(errp
, -ret
, "Could not read unknown qcow2 header "
547 if (header
.backing_file_offset
> s
->cluster_size
) {
548 error_setg(errp
, "Invalid backing file offset");
553 if (header
.backing_file_offset
) {
554 ext_end
= header
.backing_file_offset
;
556 ext_end
= 1 << header
.cluster_bits
;
559 /* Handle feature bits */
560 s
->incompatible_features
= header
.incompatible_features
;
561 s
->compatible_features
= header
.compatible_features
;
562 s
->autoclear_features
= header
.autoclear_features
;
564 if (s
->incompatible_features
& ~QCOW2_INCOMPAT_MASK
) {
565 void *feature_table
= NULL
;
566 qcow2_read_extensions(bs
, header
.header_length
, ext_end
,
567 &feature_table
, NULL
);
568 report_unsupported_feature(bs
, errp
, feature_table
,
569 s
->incompatible_features
&
570 ~QCOW2_INCOMPAT_MASK
);
572 g_free(feature_table
);
576 if (s
->incompatible_features
& QCOW2_INCOMPAT_CORRUPT
) {
577 /* Corrupt images may not be written to unless they are being repaired
579 if ((flags
& BDRV_O_RDWR
) && !(flags
& BDRV_O_CHECK
)) {
580 error_setg(errp
, "qcow2: Image is corrupt; cannot be opened "
587 /* Check support for various header values */
588 if (header
.refcount_order
!= 4) {
589 report_unsupported(bs
, errp
, "%d bit reference counts",
590 1 << header
.refcount_order
);
594 s
->refcount_order
= header
.refcount_order
;
596 if (header
.crypt_method
> QCOW_CRYPT_AES
) {
597 error_setg(errp
, "Unsupported encryption method: %" PRIu32
,
598 header
.crypt_method
);
602 s
->crypt_method_header
= header
.crypt_method
;
603 if (s
->crypt_method_header
) {
607 s
->l2_bits
= s
->cluster_bits
- 3; /* L2 is always one cluster */
608 s
->l2_size
= 1 << s
->l2_bits
;
609 bs
->total_sectors
= header
.size
/ 512;
610 s
->csize_shift
= (62 - (s
->cluster_bits
- 8));
611 s
->csize_mask
= (1 << (s
->cluster_bits
- 8)) - 1;
612 s
->cluster_offset_mask
= (1LL << s
->csize_shift
) - 1;
614 s
->refcount_table_offset
= header
.refcount_table_offset
;
615 s
->refcount_table_size
=
616 header
.refcount_table_clusters
<< (s
->cluster_bits
- 3);
618 if (header
.refcount_table_clusters
> qcow2_max_refcount_clusters(s
)) {
619 error_setg(errp
, "Reference count table too large");
624 ret
= validate_table_offset(bs
, s
->refcount_table_offset
,
625 s
->refcount_table_size
, sizeof(uint64_t));
627 error_setg(errp
, "Invalid reference count table offset");
631 /* Snapshot table offset/length */
632 if (header
.nb_snapshots
> QCOW_MAX_SNAPSHOTS
) {
633 error_setg(errp
, "Too many snapshots");
638 ret
= validate_table_offset(bs
, header
.snapshots_offset
,
640 sizeof(QCowSnapshotHeader
));
642 error_setg(errp
, "Invalid snapshot table offset");
646 /* read the level 1 table */
647 if (header
.l1_size
> QCOW_MAX_L1_SIZE
) {
648 error_setg(errp
, "Active L1 table too large");
652 s
->l1_size
= header
.l1_size
;
654 l1_vm_state_index
= size_to_l1(s
, header
.size
);
655 if (l1_vm_state_index
> INT_MAX
) {
656 error_setg(errp
, "Image is too big");
660 s
->l1_vm_state_index
= l1_vm_state_index
;
662 /* the L1 table must contain at least enough entries to put
664 if (s
->l1_size
< s
->l1_vm_state_index
) {
665 error_setg(errp
, "L1 table is too small");
670 ret
= validate_table_offset(bs
, header
.l1_table_offset
,
671 header
.l1_size
, sizeof(uint64_t));
673 error_setg(errp
, "Invalid L1 table offset");
676 s
->l1_table_offset
= header
.l1_table_offset
;
679 if (s
->l1_size
> 0) {
680 s
->l1_table
= g_malloc0(
681 align_offset(s
->l1_size
* sizeof(uint64_t), 512));
682 ret
= bdrv_pread(bs
->file
, s
->l1_table_offset
, s
->l1_table
,
683 s
->l1_size
* sizeof(uint64_t));
685 error_setg_errno(errp
, -ret
, "Could not read L1 table");
688 for(i
= 0;i
< s
->l1_size
; i
++) {
689 be64_to_cpus(&s
->l1_table
[i
]);
693 /* alloc L2 table/refcount block cache */
694 s
->l2_table_cache
= qcow2_cache_create(bs
, L2_CACHE_SIZE
);
695 s
->refcount_block_cache
= qcow2_cache_create(bs
, REFCOUNT_CACHE_SIZE
);
697 s
->cluster_cache
= g_malloc(s
->cluster_size
);
698 /* one more sector for decompressed data alignment */
699 s
->cluster_data
= qemu_blockalign(bs
, QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
701 s
->cluster_cache_offset
= -1;
704 ret
= qcow2_refcount_init(bs
);
706 error_setg_errno(errp
, -ret
, "Could not initialize refcount handling");
710 QLIST_INIT(&s
->cluster_allocs
);
711 QTAILQ_INIT(&s
->discards
);
713 /* read qcow2 extensions */
714 if (qcow2_read_extensions(bs
, header
.header_length
, ext_end
, NULL
,
716 error_propagate(errp
, local_err
);
721 /* read the backing file name */
722 if (header
.backing_file_offset
!= 0) {
723 len
= header
.backing_file_size
;
724 if (len
> MIN(1023, s
->cluster_size
- header
.backing_file_offset
)) {
725 error_setg(errp
, "Backing file name too long");
729 ret
= bdrv_pread(bs
->file
, header
.backing_file_offset
,
730 bs
->backing_file
, len
);
732 error_setg_errno(errp
, -ret
, "Could not read backing file name");
735 bs
->backing_file
[len
] = '\0';
738 /* Internal snapshots */
739 s
->snapshots_offset
= header
.snapshots_offset
;
740 s
->nb_snapshots
= header
.nb_snapshots
;
742 ret
= qcow2_read_snapshots(bs
);
744 error_setg_errno(errp
, -ret
, "Could not read snapshots");
748 /* Clear unknown autoclear feature bits */
749 if (!bs
->read_only
&& !(flags
& BDRV_O_INCOMING
) && s
->autoclear_features
) {
750 s
->autoclear_features
= 0;
751 ret
= qcow2_update_header(bs
);
753 error_setg_errno(errp
, -ret
, "Could not update qcow2 header");
758 /* Initialise locks */
759 qemu_co_mutex_init(&s
->lock
);
761 /* Repair image if dirty */
762 if (!(flags
& (BDRV_O_CHECK
| BDRV_O_INCOMING
)) && !bs
->read_only
&&
763 (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
)) {
764 BdrvCheckResult result
= {0};
766 ret
= qcow2_check(bs
, &result
, BDRV_FIX_ERRORS
);
768 error_setg_errno(errp
, -ret
, "Could not repair dirty image");
773 /* Enable lazy_refcounts according to image and command line options */
774 opts
= qemu_opts_create(&qcow2_runtime_opts
, NULL
, 0, &error_abort
);
775 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
777 error_propagate(errp
, local_err
);
782 s
->use_lazy_refcounts
= qemu_opt_get_bool(opts
, QCOW2_OPT_LAZY_REFCOUNTS
,
783 (s
->compatible_features
& QCOW2_COMPAT_LAZY_REFCOUNTS
));
785 s
->discard_passthrough
[QCOW2_DISCARD_NEVER
] = false;
786 s
->discard_passthrough
[QCOW2_DISCARD_ALWAYS
] = true;
787 s
->discard_passthrough
[QCOW2_DISCARD_REQUEST
] =
788 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_REQUEST
,
789 flags
& BDRV_O_UNMAP
);
790 s
->discard_passthrough
[QCOW2_DISCARD_SNAPSHOT
] =
791 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_SNAPSHOT
, true);
792 s
->discard_passthrough
[QCOW2_DISCARD_OTHER
] =
793 qemu_opt_get_bool(opts
, QCOW2_OPT_DISCARD_OTHER
, false);
795 opt_overlap_check
= qemu_opt_get(opts
, "overlap-check") ?: "cached";
796 if (!strcmp(opt_overlap_check
, "none")) {
797 overlap_check_template
= 0;
798 } else if (!strcmp(opt_overlap_check
, "constant")) {
799 overlap_check_template
= QCOW2_OL_CONSTANT
;
800 } else if (!strcmp(opt_overlap_check
, "cached")) {
801 overlap_check_template
= QCOW2_OL_CACHED
;
802 } else if (!strcmp(opt_overlap_check
, "all")) {
803 overlap_check_template
= QCOW2_OL_ALL
;
805 error_setg(errp
, "Unsupported value '%s' for qcow2 option "
806 "'overlap-check'. Allowed are either of the following: "
807 "none, constant, cached, all", opt_overlap_check
);
813 s
->overlap_check
= 0;
814 for (i
= 0; i
< QCOW2_OL_MAX_BITNR
; i
++) {
815 /* overlap-check defines a template bitmask, but every flag may be
816 * overwritten through the associated boolean option */
818 qemu_opt_get_bool(opts
, overlap_bool_option_names
[i
],
819 overlap_check_template
& (1 << i
)) << i
;
824 if (s
->use_lazy_refcounts
&& s
->qcow_version
< 3) {
825 error_setg(errp
, "Lazy refcounts require a qcow2 image with at least "
826 "qemu 1.1 compatibility level");
833 BdrvCheckResult result
= {0};
834 qcow2_check_refcounts(bs
, &result
, 0);
840 g_free(s
->unknown_header_fields
);
841 cleanup_unknown_header_ext(bs
);
842 qcow2_free_snapshots(bs
);
843 qcow2_refcount_close(bs
);
845 /* else pre-write overlap checks in cache_destroy may crash */
847 if (s
->l2_table_cache
) {
848 qcow2_cache_destroy(bs
, s
->l2_table_cache
);
850 if (s
->refcount_block_cache
) {
851 qcow2_cache_destroy(bs
, s
->refcount_block_cache
);
853 g_free(s
->cluster_cache
);
854 qemu_vfree(s
->cluster_data
);
858 static int qcow2_refresh_limits(BlockDriverState
*bs
)
860 BDRVQcowState
*s
= bs
->opaque
;
862 bs
->bl
.write_zeroes_alignment
= s
->cluster_sectors
;
867 static int qcow2_set_key(BlockDriverState
*bs
, const char *key
)
869 BDRVQcowState
*s
= bs
->opaque
;
873 memset(keybuf
, 0, 16);
877 /* XXX: we could compress the chars to 7 bits to increase
879 for(i
= 0;i
< len
;i
++) {
882 s
->crypt_method
= s
->crypt_method_header
;
884 if (AES_set_encrypt_key(keybuf
, 128, &s
->aes_encrypt_key
) != 0)
886 if (AES_set_decrypt_key(keybuf
, 128, &s
->aes_decrypt_key
) != 0)
896 AES_encrypt(in
, tmp
, &s
->aes_encrypt_key
);
897 AES_decrypt(tmp
, out
, &s
->aes_decrypt_key
);
898 for(i
= 0; i
< 16; i
++)
899 printf(" %02x", tmp
[i
]);
901 for(i
= 0; i
< 16; i
++)
902 printf(" %02x", out
[i
]);
909 /* We have no actual commit/abort logic for qcow2, but we need to write out any
910 * unwritten data if we reopen read-only. */
911 static int qcow2_reopen_prepare(BDRVReopenState
*state
,
912 BlockReopenQueue
*queue
, Error
**errp
)
916 if ((state
->flags
& BDRV_O_RDWR
) == 0) {
917 ret
= bdrv_flush(state
->bs
);
922 ret
= qcow2_mark_clean(state
->bs
);
931 static int64_t coroutine_fn
qcow2_co_get_block_status(BlockDriverState
*bs
,
932 int64_t sector_num
, int nb_sectors
, int *pnum
)
934 BDRVQcowState
*s
= bs
->opaque
;
935 uint64_t cluster_offset
;
936 int index_in_cluster
, ret
;
940 qemu_co_mutex_lock(&s
->lock
);
941 ret
= qcow2_get_cluster_offset(bs
, sector_num
<< 9, pnum
, &cluster_offset
);
942 qemu_co_mutex_unlock(&s
->lock
);
947 if (cluster_offset
!= 0 && ret
!= QCOW2_CLUSTER_COMPRESSED
&&
949 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
950 cluster_offset
|= (index_in_cluster
<< BDRV_SECTOR_BITS
);
951 status
|= BDRV_BLOCK_OFFSET_VALID
| cluster_offset
;
953 if (ret
== QCOW2_CLUSTER_ZERO
) {
954 status
|= BDRV_BLOCK_ZERO
;
955 } else if (ret
!= QCOW2_CLUSTER_UNALLOCATED
) {
956 status
|= BDRV_BLOCK_DATA
;
961 /* handle reading after the end of the backing file */
962 int qcow2_backing_read1(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
963 int64_t sector_num
, int nb_sectors
)
966 if ((sector_num
+ nb_sectors
) <= bs
->total_sectors
)
968 if (sector_num
>= bs
->total_sectors
)
971 n1
= bs
->total_sectors
- sector_num
;
973 qemu_iovec_memset(qiov
, 512 * n1
, 0, 512 * (nb_sectors
- n1
));
978 static coroutine_fn
int qcow2_co_readv(BlockDriverState
*bs
, int64_t sector_num
,
979 int remaining_sectors
, QEMUIOVector
*qiov
)
981 BDRVQcowState
*s
= bs
->opaque
;
982 int index_in_cluster
, n1
;
984 int cur_nr_sectors
; /* number of sectors in current iteration */
985 uint64_t cluster_offset
= 0;
986 uint64_t bytes_done
= 0;
987 QEMUIOVector hd_qiov
;
988 uint8_t *cluster_data
= NULL
;
990 qemu_iovec_init(&hd_qiov
, qiov
->niov
);
992 qemu_co_mutex_lock(&s
->lock
);
994 while (remaining_sectors
!= 0) {
996 /* prepare next request */
997 cur_nr_sectors
= remaining_sectors
;
998 if (s
->crypt_method
) {
999 cur_nr_sectors
= MIN(cur_nr_sectors
,
1000 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
);
1003 ret
= qcow2_get_cluster_offset(bs
, sector_num
<< 9,
1004 &cur_nr_sectors
, &cluster_offset
);
1009 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1011 qemu_iovec_reset(&hd_qiov
);
1012 qemu_iovec_concat(&hd_qiov
, qiov
, bytes_done
,
1013 cur_nr_sectors
* 512);
1016 case QCOW2_CLUSTER_UNALLOCATED
:
1018 if (bs
->backing_hd
) {
1019 /* read from the base image */
1020 n1
= qcow2_backing_read1(bs
->backing_hd
, &hd_qiov
,
1021 sector_num
, cur_nr_sectors
);
1023 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_BACKING_AIO
);
1024 qemu_co_mutex_unlock(&s
->lock
);
1025 ret
= bdrv_co_readv(bs
->backing_hd
, sector_num
,
1027 qemu_co_mutex_lock(&s
->lock
);
1033 /* Note: in this case, no need to wait */
1034 qemu_iovec_memset(&hd_qiov
, 0, 0, 512 * cur_nr_sectors
);
1038 case QCOW2_CLUSTER_ZERO
:
1039 qemu_iovec_memset(&hd_qiov
, 0, 0, 512 * cur_nr_sectors
);
1042 case QCOW2_CLUSTER_COMPRESSED
:
1043 /* add AIO support for compressed blocks ? */
1044 ret
= qcow2_decompress_cluster(bs
, cluster_offset
);
1049 qemu_iovec_from_buf(&hd_qiov
, 0,
1050 s
->cluster_cache
+ index_in_cluster
* 512,
1051 512 * cur_nr_sectors
);
1054 case QCOW2_CLUSTER_NORMAL
:
1055 if ((cluster_offset
& 511) != 0) {
1060 if (s
->crypt_method
) {
1062 * For encrypted images, read everything into a temporary
1063 * contiguous buffer on which the AES functions can work.
1065 if (!cluster_data
) {
1067 qemu_blockalign(bs
, QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
1070 assert(cur_nr_sectors
<=
1071 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
);
1072 qemu_iovec_reset(&hd_qiov
);
1073 qemu_iovec_add(&hd_qiov
, cluster_data
,
1074 512 * cur_nr_sectors
);
1077 BLKDBG_EVENT(bs
->file
, BLKDBG_READ_AIO
);
1078 qemu_co_mutex_unlock(&s
->lock
);
1079 ret
= bdrv_co_readv(bs
->file
,
1080 (cluster_offset
>> 9) + index_in_cluster
,
1081 cur_nr_sectors
, &hd_qiov
);
1082 qemu_co_mutex_lock(&s
->lock
);
1086 if (s
->crypt_method
) {
1087 qcow2_encrypt_sectors(s
, sector_num
, cluster_data
,
1088 cluster_data
, cur_nr_sectors
, 0, &s
->aes_decrypt_key
);
1089 qemu_iovec_from_buf(qiov
, bytes_done
,
1090 cluster_data
, 512 * cur_nr_sectors
);
1095 g_assert_not_reached();
1100 remaining_sectors
-= cur_nr_sectors
;
1101 sector_num
+= cur_nr_sectors
;
1102 bytes_done
+= cur_nr_sectors
* 512;
1107 qemu_co_mutex_unlock(&s
->lock
);
1109 qemu_iovec_destroy(&hd_qiov
);
1110 qemu_vfree(cluster_data
);
1115 static coroutine_fn
int qcow2_co_writev(BlockDriverState
*bs
,
1117 int remaining_sectors
,
1120 BDRVQcowState
*s
= bs
->opaque
;
1121 int index_in_cluster
;
1123 int cur_nr_sectors
; /* number of sectors in current iteration */
1124 uint64_t cluster_offset
;
1125 QEMUIOVector hd_qiov
;
1126 uint64_t bytes_done
= 0;
1127 uint8_t *cluster_data
= NULL
;
1128 QCowL2Meta
*l2meta
= NULL
;
1130 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num
,
1133 qemu_iovec_init(&hd_qiov
, qiov
->niov
);
1135 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1137 qemu_co_mutex_lock(&s
->lock
);
1139 while (remaining_sectors
!= 0) {
1143 trace_qcow2_writev_start_part(qemu_coroutine_self());
1144 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1145 cur_nr_sectors
= remaining_sectors
;
1146 if (s
->crypt_method
&&
1148 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
- index_in_cluster
) {
1150 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
- index_in_cluster
;
1153 ret
= qcow2_alloc_cluster_offset(bs
, sector_num
<< 9,
1154 &cur_nr_sectors
, &cluster_offset
, &l2meta
);
1159 assert((cluster_offset
& 511) == 0);
1161 qemu_iovec_reset(&hd_qiov
);
1162 qemu_iovec_concat(&hd_qiov
, qiov
, bytes_done
,
1163 cur_nr_sectors
* 512);
1165 if (s
->crypt_method
) {
1166 if (!cluster_data
) {
1167 cluster_data
= qemu_blockalign(bs
, QCOW_MAX_CRYPT_CLUSTERS
*
1171 assert(hd_qiov
.size
<=
1172 QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
);
1173 qemu_iovec_to_buf(&hd_qiov
, 0, cluster_data
, hd_qiov
.size
);
1175 qcow2_encrypt_sectors(s
, sector_num
, cluster_data
,
1176 cluster_data
, cur_nr_sectors
, 1, &s
->aes_encrypt_key
);
1178 qemu_iovec_reset(&hd_qiov
);
1179 qemu_iovec_add(&hd_qiov
, cluster_data
,
1180 cur_nr_sectors
* 512);
1183 ret
= qcow2_pre_write_overlap_check(bs
, 0,
1184 cluster_offset
+ index_in_cluster
* BDRV_SECTOR_SIZE
,
1185 cur_nr_sectors
* BDRV_SECTOR_SIZE
);
1190 qemu_co_mutex_unlock(&s
->lock
);
1191 BLKDBG_EVENT(bs
->file
, BLKDBG_WRITE_AIO
);
1192 trace_qcow2_writev_data(qemu_coroutine_self(),
1193 (cluster_offset
>> 9) + index_in_cluster
);
1194 ret
= bdrv_co_writev(bs
->file
,
1195 (cluster_offset
>> 9) + index_in_cluster
,
1196 cur_nr_sectors
, &hd_qiov
);
1197 qemu_co_mutex_lock(&s
->lock
);
1202 while (l2meta
!= NULL
) {
1205 ret
= qcow2_alloc_cluster_link_l2(bs
, l2meta
);
1210 /* Take the request off the list of running requests */
1211 if (l2meta
->nb_clusters
!= 0) {
1212 QLIST_REMOVE(l2meta
, next_in_flight
);
1215 qemu_co_queue_restart_all(&l2meta
->dependent_requests
);
1217 next
= l2meta
->next
;
1222 remaining_sectors
-= cur_nr_sectors
;
1223 sector_num
+= cur_nr_sectors
;
1224 bytes_done
+= cur_nr_sectors
* 512;
1225 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors
);
1230 qemu_co_mutex_unlock(&s
->lock
);
1232 while (l2meta
!= NULL
) {
1235 if (l2meta
->nb_clusters
!= 0) {
1236 QLIST_REMOVE(l2meta
, next_in_flight
);
1238 qemu_co_queue_restart_all(&l2meta
->dependent_requests
);
1240 next
= l2meta
->next
;
1245 qemu_iovec_destroy(&hd_qiov
);
1246 qemu_vfree(cluster_data
);
1247 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret
);
1252 static void qcow2_close(BlockDriverState
*bs
)
1254 BDRVQcowState
*s
= bs
->opaque
;
1255 g_free(s
->l1_table
);
1256 /* else pre-write overlap checks in cache_destroy may crash */
1259 if (!(bs
->open_flags
& BDRV_O_INCOMING
)) {
1260 qcow2_cache_flush(bs
, s
->l2_table_cache
);
1261 qcow2_cache_flush(bs
, s
->refcount_block_cache
);
1263 qcow2_mark_clean(bs
);
1266 qcow2_cache_destroy(bs
, s
->l2_table_cache
);
1267 qcow2_cache_destroy(bs
, s
->refcount_block_cache
);
1269 g_free(s
->unknown_header_fields
);
1270 cleanup_unknown_header_ext(bs
);
1272 g_free(s
->cluster_cache
);
1273 qemu_vfree(s
->cluster_data
);
1274 qcow2_refcount_close(bs
);
1275 qcow2_free_snapshots(bs
);
1278 static void qcow2_invalidate_cache(BlockDriverState
*bs
, Error
**errp
)
1280 BDRVQcowState
*s
= bs
->opaque
;
1281 int flags
= s
->flags
;
1282 AES_KEY aes_encrypt_key
;
1283 AES_KEY aes_decrypt_key
;
1284 uint32_t crypt_method
= 0;
1286 Error
*local_err
= NULL
;
1290 * Backing files are read-only which makes all of their metadata immutable,
1291 * that means we don't have to worry about reopening them here.
1294 if (s
->crypt_method
) {
1295 crypt_method
= s
->crypt_method
;
1296 memcpy(&aes_encrypt_key
, &s
->aes_encrypt_key
, sizeof(aes_encrypt_key
));
1297 memcpy(&aes_decrypt_key
, &s
->aes_decrypt_key
, sizeof(aes_decrypt_key
));
1302 bdrv_invalidate_cache(bs
->file
, &local_err
);
1304 error_propagate(errp
, local_err
);
1308 memset(s
, 0, sizeof(BDRVQcowState
));
1309 options
= qdict_clone_shallow(bs
->options
);
1311 ret
= qcow2_open(bs
, options
, flags
, &local_err
);
1314 error_setg(errp
, "Could not reopen qcow2 layer: %s",
1315 error_get_pretty(local_err
));
1316 error_free(local_err
);
1318 } else if (ret
< 0) {
1319 error_setg_errno(errp
, -ret
, "Could not reopen qcow2 layer");
1324 s
->crypt_method
= crypt_method
;
1325 memcpy(&s
->aes_encrypt_key
, &aes_encrypt_key
, sizeof(aes_encrypt_key
));
1326 memcpy(&s
->aes_decrypt_key
, &aes_decrypt_key
, sizeof(aes_decrypt_key
));
1330 static size_t header_ext_add(char *buf
, uint32_t magic
, const void *s
,
1331 size_t len
, size_t buflen
)
1333 QCowExtension
*ext_backing_fmt
= (QCowExtension
*) buf
;
1334 size_t ext_len
= sizeof(QCowExtension
) + ((len
+ 7) & ~7);
1336 if (buflen
< ext_len
) {
1340 *ext_backing_fmt
= (QCowExtension
) {
1341 .magic
= cpu_to_be32(magic
),
1342 .len
= cpu_to_be32(len
),
1344 memcpy(buf
+ sizeof(QCowExtension
), s
, len
);
1350 * Updates the qcow2 header, including the variable length parts of it, i.e.
1351 * the backing file name and all extensions. qcow2 was not designed to allow
1352 * such changes, so if we run out of space (we can only use the first cluster)
1353 * this function may fail.
1355 * Returns 0 on success, -errno in error cases.
1357 int qcow2_update_header(BlockDriverState
*bs
)
1359 BDRVQcowState
*s
= bs
->opaque
;
1362 size_t buflen
= s
->cluster_size
;
1364 uint64_t total_size
;
1365 uint32_t refcount_table_clusters
;
1366 size_t header_length
;
1367 Qcow2UnknownHeaderExtension
*uext
;
1369 buf
= qemu_blockalign(bs
, buflen
);
1371 /* Header structure */
1372 header
= (QCowHeader
*) buf
;
1374 if (buflen
< sizeof(*header
)) {
1379 header_length
= sizeof(*header
) + s
->unknown_header_fields_size
;
1380 total_size
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
1381 refcount_table_clusters
= s
->refcount_table_size
>> (s
->cluster_bits
- 3);
1383 *header
= (QCowHeader
) {
1384 /* Version 2 fields */
1385 .magic
= cpu_to_be32(QCOW_MAGIC
),
1386 .version
= cpu_to_be32(s
->qcow_version
),
1387 .backing_file_offset
= 0,
1388 .backing_file_size
= 0,
1389 .cluster_bits
= cpu_to_be32(s
->cluster_bits
),
1390 .size
= cpu_to_be64(total_size
),
1391 .crypt_method
= cpu_to_be32(s
->crypt_method_header
),
1392 .l1_size
= cpu_to_be32(s
->l1_size
),
1393 .l1_table_offset
= cpu_to_be64(s
->l1_table_offset
),
1394 .refcount_table_offset
= cpu_to_be64(s
->refcount_table_offset
),
1395 .refcount_table_clusters
= cpu_to_be32(refcount_table_clusters
),
1396 .nb_snapshots
= cpu_to_be32(s
->nb_snapshots
),
1397 .snapshots_offset
= cpu_to_be64(s
->snapshots_offset
),
1399 /* Version 3 fields */
1400 .incompatible_features
= cpu_to_be64(s
->incompatible_features
),
1401 .compatible_features
= cpu_to_be64(s
->compatible_features
),
1402 .autoclear_features
= cpu_to_be64(s
->autoclear_features
),
1403 .refcount_order
= cpu_to_be32(s
->refcount_order
),
1404 .header_length
= cpu_to_be32(header_length
),
1407 /* For older versions, write a shorter header */
1408 switch (s
->qcow_version
) {
1410 ret
= offsetof(QCowHeader
, incompatible_features
);
1413 ret
= sizeof(*header
);
1422 memset(buf
, 0, buflen
);
1424 /* Preserve any unknown field in the header */
1425 if (s
->unknown_header_fields_size
) {
1426 if (buflen
< s
->unknown_header_fields_size
) {
1431 memcpy(buf
, s
->unknown_header_fields
, s
->unknown_header_fields_size
);
1432 buf
+= s
->unknown_header_fields_size
;
1433 buflen
-= s
->unknown_header_fields_size
;
1436 /* Backing file format header extension */
1437 if (*bs
->backing_format
) {
1438 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_BACKING_FORMAT
,
1439 bs
->backing_format
, strlen(bs
->backing_format
),
1450 Qcow2Feature features
[] = {
1452 .type
= QCOW2_FEAT_TYPE_INCOMPATIBLE
,
1453 .bit
= QCOW2_INCOMPAT_DIRTY_BITNR
,
1454 .name
= "dirty bit",
1457 .type
= QCOW2_FEAT_TYPE_INCOMPATIBLE
,
1458 .bit
= QCOW2_INCOMPAT_CORRUPT_BITNR
,
1459 .name
= "corrupt bit",
1462 .type
= QCOW2_FEAT_TYPE_COMPATIBLE
,
1463 .bit
= QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR
,
1464 .name
= "lazy refcounts",
1468 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_FEATURE_TABLE
,
1469 features
, sizeof(features
), buflen
);
1476 /* Keep unknown header extensions */
1477 QLIST_FOREACH(uext
, &s
->unknown_header_ext
, next
) {
1478 ret
= header_ext_add(buf
, uext
->magic
, uext
->data
, uext
->len
, buflen
);
1487 /* End of header extensions */
1488 ret
= header_ext_add(buf
, QCOW2_EXT_MAGIC_END
, NULL
, 0, buflen
);
1496 /* Backing file name */
1497 if (*bs
->backing_file
) {
1498 size_t backing_file_len
= strlen(bs
->backing_file
);
1500 if (buflen
< backing_file_len
) {
1505 /* Using strncpy is ok here, since buf is not NUL-terminated. */
1506 strncpy(buf
, bs
->backing_file
, buflen
);
1508 header
->backing_file_offset
= cpu_to_be64(buf
- ((char*) header
));
1509 header
->backing_file_size
= cpu_to_be32(backing_file_len
);
1512 /* Write the new header */
1513 ret
= bdrv_pwrite(bs
->file
, 0, header
, s
->cluster_size
);
1524 static int qcow2_change_backing_file(BlockDriverState
*bs
,
1525 const char *backing_file
, const char *backing_fmt
)
1527 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
1528 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
1530 return qcow2_update_header(bs
);
1533 static int preallocate(BlockDriverState
*bs
)
1535 uint64_t nb_sectors
;
1537 uint64_t host_offset
= 0;
1542 nb_sectors
= bdrv_getlength(bs
) >> BDRV_SECTOR_BITS
;
1545 while (nb_sectors
) {
1546 num
= MIN(nb_sectors
, INT_MAX
>> BDRV_SECTOR_BITS
);
1547 ret
= qcow2_alloc_cluster_offset(bs
, offset
, &num
,
1548 &host_offset
, &meta
);
1554 QCowL2Meta
*next
= meta
->next
;
1556 ret
= qcow2_alloc_cluster_link_l2(bs
, meta
);
1558 qcow2_free_any_clusters(bs
, meta
->alloc_offset
,
1559 meta
->nb_clusters
, QCOW2_DISCARD_NEVER
);
1563 /* There are no dependent requests, but we need to remove our
1564 * request from the list of in-flight requests */
1565 QLIST_REMOVE(meta
, next_in_flight
);
1571 /* TODO Preallocate data if requested */
1574 offset
+= num
<< BDRV_SECTOR_BITS
;
1578 * It is expected that the image file is large enough to actually contain
1579 * all of the allocated clusters (otherwise we get failing reads after
1580 * EOF). Extend the image to the last allocated sector.
1582 if (host_offset
!= 0) {
1583 uint8_t buf
[BDRV_SECTOR_SIZE
];
1584 memset(buf
, 0, BDRV_SECTOR_SIZE
);
1585 ret
= bdrv_write(bs
->file
, (host_offset
>> BDRV_SECTOR_BITS
) + num
- 1,
1595 static int qcow2_create2(const char *filename
, int64_t total_size
,
1596 const char *backing_file
, const char *backing_format
,
1597 int flags
, size_t cluster_size
, int prealloc
,
1598 QemuOpts
*opts
, int version
,
1601 /* Calculate cluster_bits */
1603 cluster_bits
= ffs(cluster_size
) - 1;
1604 if (cluster_bits
< MIN_CLUSTER_BITS
|| cluster_bits
> MAX_CLUSTER_BITS
||
1605 (1 << cluster_bits
) != cluster_size
)
1607 error_setg(errp
, "Cluster size must be a power of two between %d and "
1608 "%dk", 1 << MIN_CLUSTER_BITS
, 1 << (MAX_CLUSTER_BITS
- 10));
1613 * Open the image file and write a minimal qcow2 header.
1615 * We keep things simple and start with a zero-sized image. We also
1616 * do without refcount blocks or a L1 table for now. We'll fix the
1617 * inconsistency later.
1619 * We do need a refcount table because growing the refcount table means
1620 * allocating two new refcount blocks - the seconds of which would be at
1621 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
1622 * size for any qcow2 image.
1624 BlockDriverState
* bs
;
1626 uint64_t* refcount_table
;
1627 Error
*local_err
= NULL
;
1630 ret
= bdrv_create_file(filename
, opts
, &local_err
);
1632 error_propagate(errp
, local_err
);
1637 ret
= bdrv_open(&bs
, filename
, NULL
, NULL
, BDRV_O_RDWR
| BDRV_O_PROTOCOL
,
1640 error_propagate(errp
, local_err
);
1644 /* Write the header */
1645 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS
) < sizeof(*header
));
1646 header
= g_malloc0(cluster_size
);
1647 *header
= (QCowHeader
) {
1648 .magic
= cpu_to_be32(QCOW_MAGIC
),
1649 .version
= cpu_to_be32(version
),
1650 .cluster_bits
= cpu_to_be32(cluster_bits
),
1651 .size
= cpu_to_be64(0),
1652 .l1_table_offset
= cpu_to_be64(0),
1653 .l1_size
= cpu_to_be32(0),
1654 .refcount_table_offset
= cpu_to_be64(cluster_size
),
1655 .refcount_table_clusters
= cpu_to_be32(1),
1656 .refcount_order
= cpu_to_be32(3 + REFCOUNT_SHIFT
),
1657 .header_length
= cpu_to_be32(sizeof(*header
)),
1660 if (flags
& BLOCK_FLAG_ENCRYPT
) {
1661 header
->crypt_method
= cpu_to_be32(QCOW_CRYPT_AES
);
1663 header
->crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
1666 if (flags
& BLOCK_FLAG_LAZY_REFCOUNTS
) {
1667 header
->compatible_features
|=
1668 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS
);
1671 ret
= bdrv_pwrite(bs
, 0, header
, cluster_size
);
1674 error_setg_errno(errp
, -ret
, "Could not write qcow2 header");
1678 /* Write a refcount table with one refcount block */
1679 refcount_table
= g_malloc0(2 * cluster_size
);
1680 refcount_table
[0] = cpu_to_be64(2 * cluster_size
);
1681 ret
= bdrv_pwrite(bs
, cluster_size
, refcount_table
, 2 * cluster_size
);
1682 g_free(refcount_table
);
1685 error_setg_errno(errp
, -ret
, "Could not write refcount table");
1693 * And now open the image and make it consistent first (i.e. increase the
1694 * refcount of the cluster that is occupied by the header and the refcount
1697 BlockDriver
* drv
= bdrv_find_format("qcow2");
1698 assert(drv
!= NULL
);
1699 ret
= bdrv_open(&bs
, filename
, NULL
, NULL
,
1700 BDRV_O_RDWR
| BDRV_O_CACHE_WB
| BDRV_O_NO_FLUSH
, drv
, &local_err
);
1702 error_propagate(errp
, local_err
);
1706 ret
= qcow2_alloc_clusters(bs
, 3 * cluster_size
);
1708 error_setg_errno(errp
, -ret
, "Could not allocate clusters for qcow2 "
1709 "header and refcount table");
1712 } else if (ret
!= 0) {
1713 error_report("Huh, first cluster in empty image is already in use?");
1717 /* Okay, now that we have a valid image, let's give it the right size */
1718 ret
= bdrv_truncate(bs
, total_size
* BDRV_SECTOR_SIZE
);
1720 error_setg_errno(errp
, -ret
, "Could not resize image");
1724 /* Want a backing file? There you go.*/
1726 ret
= bdrv_change_backing_file(bs
, backing_file
, backing_format
);
1728 error_setg_errno(errp
, -ret
, "Could not assign backing file '%s' "
1729 "with format '%s'", backing_file
, backing_format
);
1734 /* And if we're supposed to preallocate metadata, do that now */
1736 BDRVQcowState
*s
= bs
->opaque
;
1737 qemu_co_mutex_lock(&s
->lock
);
1738 ret
= preallocate(bs
);
1739 qemu_co_mutex_unlock(&s
->lock
);
1741 error_setg_errno(errp
, -ret
, "Could not preallocate metadata");
1749 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */
1750 ret
= bdrv_open(&bs
, filename
, NULL
, NULL
,
1751 BDRV_O_RDWR
| BDRV_O_CACHE_WB
| BDRV_O_NO_BACKING
,
1754 error_propagate(errp
, local_err
);
1766 static int qcow2_create(const char *filename
, QemuOpts
*opts
, Error
**errp
)
1768 char *backing_file
= NULL
;
1769 char *backing_fmt
= NULL
;
1771 uint64_t sectors
= 0;
1773 size_t cluster_size
= DEFAULT_CLUSTER_SIZE
;
1776 Error
*local_err
= NULL
;
1779 /* Read out options */
1780 sectors
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0) / 512;
1781 backing_file
= qemu_opt_get_del(opts
, BLOCK_OPT_BACKING_FILE
);
1782 backing_fmt
= qemu_opt_get_del(opts
, BLOCK_OPT_BACKING_FMT
);
1783 if (qemu_opt_get_bool_del(opts
, BLOCK_OPT_ENCRYPT
, false)) {
1784 flags
|= BLOCK_FLAG_ENCRYPT
;
1786 cluster_size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_CLUSTER_SIZE
,
1787 DEFAULT_CLUSTER_SIZE
);
1788 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
1789 if (!buf
|| !strcmp(buf
, "off")) {
1791 } else if (!strcmp(buf
, "metadata")) {
1794 error_setg(errp
, "Invalid preallocation mode: '%s'", buf
);
1799 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_COMPAT_LEVEL
);
1801 /* keep the default */
1802 } else if (!strcmp(buf
, "0.10")) {
1804 } else if (!strcmp(buf
, "1.1")) {
1807 error_setg(errp
, "Invalid compatibility level: '%s'", buf
);
1812 if (qemu_opt_get_bool_del(opts
, BLOCK_OPT_LAZY_REFCOUNTS
, false)) {
1813 flags
|= BLOCK_FLAG_LAZY_REFCOUNTS
;
1816 if (backing_file
&& prealloc
) {
1817 error_setg(errp
, "Backing file and preallocation cannot be used at "
1823 if (version
< 3 && (flags
& BLOCK_FLAG_LAZY_REFCOUNTS
)) {
1824 error_setg(errp
, "Lazy refcounts only supported with compatibility "
1825 "level 1.1 and above (use compat=1.1 or greater)");
1830 ret
= qcow2_create2(filename
, sectors
, backing_file
, backing_fmt
, flags
,
1831 cluster_size
, prealloc
, opts
, version
, &local_err
);
1833 error_propagate(errp
, local_err
);
1837 g_free(backing_file
);
1838 g_free(backing_fmt
);
1843 static coroutine_fn
int qcow2_co_write_zeroes(BlockDriverState
*bs
,
1844 int64_t sector_num
, int nb_sectors
, BdrvRequestFlags flags
)
1847 BDRVQcowState
*s
= bs
->opaque
;
1849 /* Emulate misaligned zero writes */
1850 if (sector_num
% s
->cluster_sectors
|| nb_sectors
% s
->cluster_sectors
) {
1854 /* Whatever is left can use real zero clusters */
1855 qemu_co_mutex_lock(&s
->lock
);
1856 ret
= qcow2_zero_clusters(bs
, sector_num
<< BDRV_SECTOR_BITS
,
1858 qemu_co_mutex_unlock(&s
->lock
);
1863 static coroutine_fn
int qcow2_co_discard(BlockDriverState
*bs
,
1864 int64_t sector_num
, int nb_sectors
)
1867 BDRVQcowState
*s
= bs
->opaque
;
1869 qemu_co_mutex_lock(&s
->lock
);
1870 ret
= qcow2_discard_clusters(bs
, sector_num
<< BDRV_SECTOR_BITS
,
1871 nb_sectors
, QCOW2_DISCARD_REQUEST
);
1872 qemu_co_mutex_unlock(&s
->lock
);
1876 static int qcow2_truncate(BlockDriverState
*bs
, int64_t offset
)
1878 BDRVQcowState
*s
= bs
->opaque
;
1879 int64_t new_l1_size
;
1883 error_report("The new size must be a multiple of 512");
1887 /* cannot proceed if image has snapshots */
1888 if (s
->nb_snapshots
) {
1889 error_report("Can't resize an image which has snapshots");
1893 /* shrinking is currently not supported */
1894 if (offset
< bs
->total_sectors
* 512) {
1895 error_report("qcow2 doesn't support shrinking images yet");
1899 new_l1_size
= size_to_l1(s
, offset
);
1900 ret
= qcow2_grow_l1_table(bs
, new_l1_size
, true);
1905 /* write updated header.size */
1906 offset
= cpu_to_be64(offset
);
1907 ret
= bdrv_pwrite_sync(bs
->file
, offsetof(QCowHeader
, size
),
1908 &offset
, sizeof(uint64_t));
1913 s
->l1_vm_state_index
= new_l1_size
;
1917 /* XXX: put compressed sectors first, then all the cluster aligned
1918 tables to avoid losing bytes in alignment */
1919 static int qcow2_write_compressed(BlockDriverState
*bs
, int64_t sector_num
,
1920 const uint8_t *buf
, int nb_sectors
)
1922 BDRVQcowState
*s
= bs
->opaque
;
1926 uint64_t cluster_offset
;
1928 if (nb_sectors
== 0) {
1929 /* align end of file to a sector boundary to ease reading with
1930 sector based I/Os */
1931 cluster_offset
= bdrv_getlength(bs
->file
);
1932 cluster_offset
= (cluster_offset
+ 511) & ~511;
1933 bdrv_truncate(bs
->file
, cluster_offset
);
1937 if (nb_sectors
!= s
->cluster_sectors
) {
1940 /* Zero-pad last write if image size is not cluster aligned */
1941 if (sector_num
+ nb_sectors
== bs
->total_sectors
&&
1942 nb_sectors
< s
->cluster_sectors
) {
1943 uint8_t *pad_buf
= qemu_blockalign(bs
, s
->cluster_size
);
1944 memset(pad_buf
, 0, s
->cluster_size
);
1945 memcpy(pad_buf
, buf
, nb_sectors
* BDRV_SECTOR_SIZE
);
1946 ret
= qcow2_write_compressed(bs
, sector_num
,
1947 pad_buf
, s
->cluster_sectors
);
1948 qemu_vfree(pad_buf
);
1953 out_buf
= g_malloc(s
->cluster_size
+ (s
->cluster_size
/ 1000) + 128);
1955 /* best compression, small window, no zlib header */
1956 memset(&strm
, 0, sizeof(strm
));
1957 ret
= deflateInit2(&strm
, Z_DEFAULT_COMPRESSION
,
1959 9, Z_DEFAULT_STRATEGY
);
1965 strm
.avail_in
= s
->cluster_size
;
1966 strm
.next_in
= (uint8_t *)buf
;
1967 strm
.avail_out
= s
->cluster_size
;
1968 strm
.next_out
= out_buf
;
1970 ret
= deflate(&strm
, Z_FINISH
);
1971 if (ret
!= Z_STREAM_END
&& ret
!= Z_OK
) {
1976 out_len
= strm
.next_out
- out_buf
;
1980 if (ret
!= Z_STREAM_END
|| out_len
>= s
->cluster_size
) {
1981 /* could not compress: write normal cluster */
1982 ret
= bdrv_write(bs
, sector_num
, buf
, s
->cluster_sectors
);
1987 cluster_offset
= qcow2_alloc_compressed_cluster_offset(bs
,
1988 sector_num
<< 9, out_len
);
1989 if (!cluster_offset
) {
1993 cluster_offset
&= s
->cluster_offset_mask
;
1995 ret
= qcow2_pre_write_overlap_check(bs
, 0, cluster_offset
, out_len
);
2000 BLKDBG_EVENT(bs
->file
, BLKDBG_WRITE_COMPRESSED
);
2001 ret
= bdrv_pwrite(bs
->file
, cluster_offset
, out_buf
, out_len
);
2013 static coroutine_fn
int qcow2_co_flush_to_os(BlockDriverState
*bs
)
2015 BDRVQcowState
*s
= bs
->opaque
;
2018 qemu_co_mutex_lock(&s
->lock
);
2019 ret
= qcow2_cache_flush(bs
, s
->l2_table_cache
);
2021 qemu_co_mutex_unlock(&s
->lock
);
2025 if (qcow2_need_accurate_refcounts(s
)) {
2026 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
2028 qemu_co_mutex_unlock(&s
->lock
);
2032 qemu_co_mutex_unlock(&s
->lock
);
2037 static int qcow2_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
2039 BDRVQcowState
*s
= bs
->opaque
;
2040 bdi
->unallocated_blocks_are_zero
= true;
2041 bdi
->can_write_zeroes_with_unmap
= (s
->qcow_version
>= 3);
2042 bdi
->cluster_size
= s
->cluster_size
;
2043 bdi
->vm_state_offset
= qcow2_vm_state_offset(s
);
2047 static ImageInfoSpecific
*qcow2_get_specific_info(BlockDriverState
*bs
)
2049 BDRVQcowState
*s
= bs
->opaque
;
2050 ImageInfoSpecific
*spec_info
= g_new(ImageInfoSpecific
, 1);
2052 *spec_info
= (ImageInfoSpecific
){
2053 .kind
= IMAGE_INFO_SPECIFIC_KIND_QCOW2
,
2055 .qcow2
= g_new(ImageInfoSpecificQCow2
, 1),
2058 if (s
->qcow_version
== 2) {
2059 *spec_info
->qcow2
= (ImageInfoSpecificQCow2
){
2060 .compat
= g_strdup("0.10"),
2062 } else if (s
->qcow_version
== 3) {
2063 *spec_info
->qcow2
= (ImageInfoSpecificQCow2
){
2064 .compat
= g_strdup("1.1"),
2065 .lazy_refcounts
= s
->compatible_features
&
2066 QCOW2_COMPAT_LAZY_REFCOUNTS
,
2067 .has_lazy_refcounts
= true,
2075 static void dump_refcounts(BlockDriverState
*bs
)
2077 BDRVQcowState
*s
= bs
->opaque
;
2078 int64_t nb_clusters
, k
, k1
, size
;
2081 size
= bdrv_getlength(bs
->file
);
2082 nb_clusters
= size_to_clusters(s
, size
);
2083 for(k
= 0; k
< nb_clusters
;) {
2085 refcount
= get_refcount(bs
, k
);
2087 while (k
< nb_clusters
&& get_refcount(bs
, k
) == refcount
)
2089 printf("%" PRId64
": refcount=%d nb=%" PRId64
"\n", k
, refcount
,
2095 static int qcow2_save_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
2098 BDRVQcowState
*s
= bs
->opaque
;
2099 int64_t total_sectors
= bs
->total_sectors
;
2100 int growable
= bs
->growable
;
2101 bool zero_beyond_eof
= bs
->zero_beyond_eof
;
2104 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_SAVE
);
2106 bs
->zero_beyond_eof
= false;
2107 ret
= bdrv_pwritev(bs
, qcow2_vm_state_offset(s
) + pos
, qiov
);
2108 bs
->growable
= growable
;
2109 bs
->zero_beyond_eof
= zero_beyond_eof
;
2111 /* bdrv_co_do_writev will have increased the total_sectors value to include
2112 * the VM state - the VM state is however not an actual part of the block
2113 * device, therefore, we need to restore the old value. */
2114 bs
->total_sectors
= total_sectors
;
2119 static int qcow2_load_vmstate(BlockDriverState
*bs
, uint8_t *buf
,
2120 int64_t pos
, int size
)
2122 BDRVQcowState
*s
= bs
->opaque
;
2123 int growable
= bs
->growable
;
2124 bool zero_beyond_eof
= bs
->zero_beyond_eof
;
2127 BLKDBG_EVENT(bs
->file
, BLKDBG_VMSTATE_LOAD
);
2129 bs
->zero_beyond_eof
= false;
2130 ret
= bdrv_pread(bs
, qcow2_vm_state_offset(s
) + pos
, buf
, size
);
2131 bs
->growable
= growable
;
2132 bs
->zero_beyond_eof
= zero_beyond_eof
;
2138 * Downgrades an image's version. To achieve this, any incompatible features
2139 * have to be removed.
2141 static int qcow2_downgrade(BlockDriverState
*bs
, int target_version
)
2143 BDRVQcowState
*s
= bs
->opaque
;
2144 int current_version
= s
->qcow_version
;
2147 if (target_version
== current_version
) {
2149 } else if (target_version
> current_version
) {
2151 } else if (target_version
!= 2) {
2155 if (s
->refcount_order
!= 4) {
2156 /* we would have to convert the image to a refcount_order == 4 image
2157 * here; however, since qemu (at the time of writing this) does not
2158 * support anything different than 4 anyway, there is no point in doing
2159 * so right now; however, we should error out (if qemu supports this in
2160 * the future and this code has not been adapted) */
2161 error_report("qcow2_downgrade: Image refcount orders other than 4 are "
2162 "currently not supported.");
2166 /* clear incompatible features */
2167 if (s
->incompatible_features
& QCOW2_INCOMPAT_DIRTY
) {
2168 ret
= qcow2_mark_clean(bs
);
2174 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
2175 * the first place; if that happens nonetheless, returning -ENOTSUP is the
2176 * best thing to do anyway */
2178 if (s
->incompatible_features
) {
2182 /* since we can ignore compatible features, we can set them to 0 as well */
2183 s
->compatible_features
= 0;
2184 /* if lazy refcounts have been used, they have already been fixed through
2185 * clearing the dirty flag */
2187 /* clearing autoclear features is trivial */
2188 s
->autoclear_features
= 0;
2190 ret
= qcow2_expand_zero_clusters(bs
);
2195 s
->qcow_version
= target_version
;
2196 ret
= qcow2_update_header(bs
);
2198 s
->qcow_version
= current_version
;
2204 static int qcow2_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
)
2206 BDRVQcowState
*s
= bs
->opaque
;
2207 int old_version
= s
->qcow_version
, new_version
= old_version
;
2208 uint64_t new_size
= 0;
2209 const char *backing_file
= NULL
, *backing_format
= NULL
;
2210 bool lazy_refcounts
= s
->use_lazy_refcounts
;
2211 const char *compat
= NULL
;
2212 uint64_t cluster_size
= s
->cluster_size
;
2215 QemuOptDesc
*desc
= opts
->list
->desc
;
2217 while (desc
&& desc
->name
) {
2218 if (!qemu_opt_find(opts
, desc
->name
)) {
2219 /* only change explicitly defined options */
2224 if (!strcmp(desc
->name
, "compat")) {
2225 compat
= qemu_opt_get(opts
, "compat");
2227 /* preserve default */
2228 } else if (!strcmp(compat
, "0.10")) {
2230 } else if (!strcmp(compat
, "1.1")) {
2233 fprintf(stderr
, "Unknown compatibility level %s.\n", compat
);
2236 } else if (!strcmp(desc
->name
, "preallocation")) {
2237 fprintf(stderr
, "Cannot change preallocation mode.\n");
2239 } else if (!strcmp(desc
->name
, "size")) {
2240 new_size
= qemu_opt_get_size(opts
, "size", 0);
2241 } else if (!strcmp(desc
->name
, "backing_file")) {
2242 backing_file
= qemu_opt_get(opts
, "backing_file");
2243 } else if (!strcmp(desc
->name
, "backing_fmt")) {
2244 backing_format
= qemu_opt_get(opts
, "backing_fmt");
2245 } else if (!strcmp(desc
->name
, "encryption")) {
2246 encrypt
= qemu_opt_get_bool(opts
, "encryption", s
->crypt_method
);
2247 if (encrypt
!= !!s
->crypt_method
) {
2248 fprintf(stderr
, "Changing the encryption flag is not "
2252 } else if (!strcmp(desc
->name
, "cluster_size")) {
2253 cluster_size
= qemu_opt_get_size(opts
, "cluster_size",
2255 if (cluster_size
!= s
->cluster_size
) {
2256 fprintf(stderr
, "Changing the cluster size is not "
2260 } else if (!strcmp(desc
->name
, "lazy_refcounts")) {
2261 lazy_refcounts
= qemu_opt_get_bool(opts
, "lazy_refcounts",
2264 /* if this assertion fails, this probably means a new option was
2265 * added without having it covered here */
2272 if (new_version
!= old_version
) {
2273 if (new_version
> old_version
) {
2275 s
->qcow_version
= new_version
;
2276 ret
= qcow2_update_header(bs
);
2278 s
->qcow_version
= old_version
;
2282 ret
= qcow2_downgrade(bs
, new_version
);
2289 if (backing_file
|| backing_format
) {
2290 ret
= qcow2_change_backing_file(bs
, backing_file
?: bs
->backing_file
,
2291 backing_format
?: bs
->backing_format
);
2297 if (s
->use_lazy_refcounts
!= lazy_refcounts
) {
2298 if (lazy_refcounts
) {
2299 if (s
->qcow_version
< 3) {
2300 fprintf(stderr
, "Lazy refcounts only supported with compatibility "
2301 "level 1.1 and above (use compat=1.1 or greater)\n");
2304 s
->compatible_features
|= QCOW2_COMPAT_LAZY_REFCOUNTS
;
2305 ret
= qcow2_update_header(bs
);
2307 s
->compatible_features
&= ~QCOW2_COMPAT_LAZY_REFCOUNTS
;
2310 s
->use_lazy_refcounts
= true;
2312 /* make image clean first */
2313 ret
= qcow2_mark_clean(bs
);
2317 /* now disallow lazy refcounts */
2318 s
->compatible_features
&= ~QCOW2_COMPAT_LAZY_REFCOUNTS
;
2319 ret
= qcow2_update_header(bs
);
2321 s
->compatible_features
|= QCOW2_COMPAT_LAZY_REFCOUNTS
;
2324 s
->use_lazy_refcounts
= false;
2329 ret
= bdrv_truncate(bs
, new_size
);
2338 static QemuOptsList qcow2_create_opts
= {
2339 .name
= "qcow2-create-opts",
2340 .head
= QTAILQ_HEAD_INITIALIZER(qcow2_create_opts
.head
),
2343 .name
= BLOCK_OPT_SIZE
,
2344 .type
= QEMU_OPT_SIZE
,
2345 .help
= "Virtual disk size"
2348 .name
= BLOCK_OPT_COMPAT_LEVEL
,
2349 .type
= QEMU_OPT_STRING
,
2350 .help
= "Compatibility level (0.10 or 1.1)"
2353 .name
= BLOCK_OPT_BACKING_FILE
,
2354 .type
= QEMU_OPT_STRING
,
2355 .help
= "File name of a base image"
2358 .name
= BLOCK_OPT_BACKING_FMT
,
2359 .type
= QEMU_OPT_STRING
,
2360 .help
= "Image format of the base image"
2363 .name
= BLOCK_OPT_ENCRYPT
,
2364 .type
= QEMU_OPT_BOOL
,
2365 .help
= "Encrypt the image",
2366 .def_value_str
= "off"
2369 .name
= BLOCK_OPT_CLUSTER_SIZE
,
2370 .type
= QEMU_OPT_SIZE
,
2371 .help
= "qcow2 cluster size",
2372 .def_value_str
= stringify(DEFAULT_CLUSTER_SIZE
)
2375 .name
= BLOCK_OPT_PREALLOC
,
2376 .type
= QEMU_OPT_STRING
,
2377 .help
= "Preallocation mode (allowed values: off, metadata)"
2380 .name
= BLOCK_OPT_LAZY_REFCOUNTS
,
2381 .type
= QEMU_OPT_BOOL
,
2382 .help
= "Postpone refcount updates",
2383 .def_value_str
= "off"
2385 { /* end of list */ }
2389 static BlockDriver bdrv_qcow2
= {
2390 .format_name
= "qcow2",
2391 .instance_size
= sizeof(BDRVQcowState
),
2392 .bdrv_probe
= qcow2_probe
,
2393 .bdrv_open
= qcow2_open
,
2394 .bdrv_close
= qcow2_close
,
2395 .bdrv_reopen_prepare
= qcow2_reopen_prepare
,
2396 .bdrv_create
= qcow2_create
,
2397 .bdrv_has_zero_init
= bdrv_has_zero_init_1
,
2398 .bdrv_co_get_block_status
= qcow2_co_get_block_status
,
2399 .bdrv_set_key
= qcow2_set_key
,
2401 .bdrv_co_readv
= qcow2_co_readv
,
2402 .bdrv_co_writev
= qcow2_co_writev
,
2403 .bdrv_co_flush_to_os
= qcow2_co_flush_to_os
,
2405 .bdrv_co_write_zeroes
= qcow2_co_write_zeroes
,
2406 .bdrv_co_discard
= qcow2_co_discard
,
2407 .bdrv_truncate
= qcow2_truncate
,
2408 .bdrv_write_compressed
= qcow2_write_compressed
,
2410 .bdrv_snapshot_create
= qcow2_snapshot_create
,
2411 .bdrv_snapshot_goto
= qcow2_snapshot_goto
,
2412 .bdrv_snapshot_delete
= qcow2_snapshot_delete
,
2413 .bdrv_snapshot_list
= qcow2_snapshot_list
,
2414 .bdrv_snapshot_load_tmp
= qcow2_snapshot_load_tmp
,
2415 .bdrv_get_info
= qcow2_get_info
,
2416 .bdrv_get_specific_info
= qcow2_get_specific_info
,
2418 .bdrv_save_vmstate
= qcow2_save_vmstate
,
2419 .bdrv_load_vmstate
= qcow2_load_vmstate
,
2421 .supports_backing
= true,
2422 .bdrv_change_backing_file
= qcow2_change_backing_file
,
2424 .bdrv_refresh_limits
= qcow2_refresh_limits
,
2425 .bdrv_invalidate_cache
= qcow2_invalidate_cache
,
2427 .create_opts
= &qcow2_create_opts
,
2428 .bdrv_check
= qcow2_check
,
2429 .bdrv_amend_options
= qcow2_amend_options
,
2432 static void bdrv_qcow2_init(void)
2434 bdrv_register(&bdrv_qcow2
);
2437 block_init(bdrv_qcow2_init
);