hw/arm: QOM'ify musicpal.c
[qemu/ar7.git] / block / qcow2.c
blobe11c7c9d1608ac3cb6f3cacd21d13ab9f9c1bd75
1 /*
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
22 * THE SOFTWARE.
24 #include "qemu/osdep.h"
25 #include "block/block_int.h"
26 #include "sysemu/block-backend.h"
27 #include "qemu/module.h"
28 #include <zlib.h>
29 #include "block/qcow2.h"
30 #include "qemu/error-report.h"
31 #include "qapi/qmp/qerror.h"
32 #include "qapi/qmp/qbool.h"
33 #include "qapi/util.h"
34 #include "qapi/qmp/types.h"
35 #include "qapi-event.h"
36 #include "trace.h"
37 #include "qemu/option_int.h"
38 #include "qemu/cutils.h"
39 #include "qemu/bswap.h"
42 Differences with QCOW:
44 - Support for multiple incremental snapshots.
45 - Memory management by reference counts.
46 - Clusters which have a reference count of one have the bit
47 QCOW_OFLAG_COPIED to optimize write performance.
48 - Size of compressed clusters is stored in sectors to reduce bit usage
49 in the cluster offsets.
50 - Support for storing additional data (such as the VM state) in the
51 snapshots.
52 - If a backing store is used, the cluster size is not constrained
53 (could be backported to QCOW).
54 - L2 tables have always a size of one cluster.
58 typedef struct {
59 uint32_t magic;
60 uint32_t len;
61 } QEMU_PACKED QCowExtension;
63 #define QCOW2_EXT_MAGIC_END 0
64 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
65 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
67 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
69 const QCowHeader *cow_header = (const void *)buf;
71 if (buf_size >= sizeof(QCowHeader) &&
72 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
73 be32_to_cpu(cow_header->version) >= 2)
74 return 100;
75 else
76 return 0;
80 /*
81 * read qcow2 extension and fill bs
82 * start reading from start_offset
83 * finish reading upon magic of value 0 or when end_offset reached
84 * unknown magic is skipped (future extension this version knows nothing about)
85 * return 0 upon success, non-0 otherwise
87 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
88 uint64_t end_offset, void **p_feature_table,
89 Error **errp)
91 BDRVQcow2State *s = bs->opaque;
92 QCowExtension ext;
93 uint64_t offset;
94 int ret;
96 #ifdef DEBUG_EXT
97 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
98 #endif
99 offset = start_offset;
100 while (offset < end_offset) {
102 #ifdef DEBUG_EXT
103 /* Sanity check */
104 if (offset > s->cluster_size)
105 printf("qcow2_read_extension: suspicious offset %lu\n", offset);
107 printf("attempting to read extended header in offset %lu\n", offset);
108 #endif
110 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext));
111 if (ret < 0) {
112 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: "
113 "pread fail from offset %" PRIu64, offset);
114 return 1;
116 be32_to_cpus(&ext.magic);
117 be32_to_cpus(&ext.len);
118 offset += sizeof(ext);
119 #ifdef DEBUG_EXT
120 printf("ext.magic = 0x%x\n", ext.magic);
121 #endif
122 if (offset > end_offset || ext.len > end_offset - offset) {
123 error_setg(errp, "Header extension too large");
124 return -EINVAL;
127 switch (ext.magic) {
128 case QCOW2_EXT_MAGIC_END:
129 return 0;
131 case QCOW2_EXT_MAGIC_BACKING_FORMAT:
132 if (ext.len >= sizeof(bs->backing_format)) {
133 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32
134 " too large (>=%zu)", ext.len,
135 sizeof(bs->backing_format));
136 return 2;
138 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len);
139 if (ret < 0) {
140 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: "
141 "Could not read format name");
142 return 3;
144 bs->backing_format[ext.len] = '\0';
145 s->image_backing_format = g_strdup(bs->backing_format);
146 #ifdef DEBUG_EXT
147 printf("Qcow2: Got format extension %s\n", bs->backing_format);
148 #endif
149 break;
151 case QCOW2_EXT_MAGIC_FEATURE_TABLE:
152 if (p_feature_table != NULL) {
153 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature));
154 ret = bdrv_pread(bs->file, offset , feature_table, ext.len);
155 if (ret < 0) {
156 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: "
157 "Could not read table");
158 return ret;
161 *p_feature_table = feature_table;
163 break;
165 default:
166 /* unknown magic - save it in case we need to rewrite the header */
168 Qcow2UnknownHeaderExtension *uext;
170 uext = g_malloc0(sizeof(*uext) + ext.len);
171 uext->magic = ext.magic;
172 uext->len = ext.len;
173 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next);
175 ret = bdrv_pread(bs->file, offset , uext->data, uext->len);
176 if (ret < 0) {
177 error_setg_errno(errp, -ret, "ERROR: unknown extension: "
178 "Could not read data");
179 return ret;
182 break;
185 offset += ((ext.len + 7) & ~7);
188 return 0;
191 static void cleanup_unknown_header_ext(BlockDriverState *bs)
193 BDRVQcow2State *s = bs->opaque;
194 Qcow2UnknownHeaderExtension *uext, *next;
196 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) {
197 QLIST_REMOVE(uext, next);
198 g_free(uext);
202 static void report_unsupported_feature(Error **errp, Qcow2Feature *table,
203 uint64_t mask)
205 char *features = g_strdup("");
206 char *old;
208 while (table && table->name[0] != '\0') {
209 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) {
210 if (mask & (1ULL << table->bit)) {
211 old = features;
212 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "",
213 table->name);
214 g_free(old);
215 mask &= ~(1ULL << table->bit);
218 table++;
221 if (mask) {
222 old = features;
223 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64,
224 old, *old ? ", " : "", mask);
225 g_free(old);
228 error_setg(errp, "Unsupported qcow2 feature(s): %s", features);
229 g_free(features);
233 * Sets the dirty bit and flushes afterwards if necessary.
235 * The incompatible_features bit is only set if the image file header was
236 * updated successfully. Therefore it is not required to check the return
237 * value of this function.
239 int qcow2_mark_dirty(BlockDriverState *bs)
241 BDRVQcow2State *s = bs->opaque;
242 uint64_t val;
243 int ret;
245 assert(s->qcow_version >= 3);
247 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
248 return 0; /* already dirty */
251 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY);
252 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features),
253 &val, sizeof(val));
254 if (ret < 0) {
255 return ret;
257 ret = bdrv_flush(bs->file->bs);
258 if (ret < 0) {
259 return ret;
262 /* Only treat image as dirty if the header was updated successfully */
263 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY;
264 return 0;
268 * Clears the dirty bit and flushes before if necessary. Only call this
269 * function when there are no pending requests, it does not guard against
270 * concurrent requests dirtying the image.
272 static int qcow2_mark_clean(BlockDriverState *bs)
274 BDRVQcow2State *s = bs->opaque;
276 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
277 int ret;
279 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY;
281 ret = bdrv_flush(bs);
282 if (ret < 0) {
283 return ret;
286 return qcow2_update_header(bs);
288 return 0;
292 * Marks the image as corrupt.
294 int qcow2_mark_corrupt(BlockDriverState *bs)
296 BDRVQcow2State *s = bs->opaque;
298 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT;
299 return qcow2_update_header(bs);
303 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
304 * before if necessary.
306 int qcow2_mark_consistent(BlockDriverState *bs)
308 BDRVQcow2State *s = bs->opaque;
310 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
311 int ret = bdrv_flush(bs);
312 if (ret < 0) {
313 return ret;
316 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT;
317 return qcow2_update_header(bs);
319 return 0;
322 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result,
323 BdrvCheckMode fix)
325 int ret = qcow2_check_refcounts(bs, result, fix);
326 if (ret < 0) {
327 return ret;
330 if (fix && result->check_errors == 0 && result->corruptions == 0) {
331 ret = qcow2_mark_clean(bs);
332 if (ret < 0) {
333 return ret;
335 return qcow2_mark_consistent(bs);
337 return ret;
340 static int validate_table_offset(BlockDriverState *bs, uint64_t offset,
341 uint64_t entries, size_t entry_len)
343 BDRVQcow2State *s = bs->opaque;
344 uint64_t size;
346 /* Use signed INT64_MAX as the maximum even for uint64_t header fields,
347 * because values will be passed to qemu functions taking int64_t. */
348 if (entries > INT64_MAX / entry_len) {
349 return -EINVAL;
352 size = entries * entry_len;
354 if (INT64_MAX - size < offset) {
355 return -EINVAL;
358 /* Tables must be cluster aligned */
359 if (offset & (s->cluster_size - 1)) {
360 return -EINVAL;
363 return 0;
366 static QemuOptsList qcow2_runtime_opts = {
367 .name = "qcow2",
368 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head),
369 .desc = {
371 .name = QCOW2_OPT_LAZY_REFCOUNTS,
372 .type = QEMU_OPT_BOOL,
373 .help = "Postpone refcount updates",
376 .name = QCOW2_OPT_DISCARD_REQUEST,
377 .type = QEMU_OPT_BOOL,
378 .help = "Pass guest discard requests to the layer below",
381 .name = QCOW2_OPT_DISCARD_SNAPSHOT,
382 .type = QEMU_OPT_BOOL,
383 .help = "Generate discard requests when snapshot related space "
384 "is freed",
387 .name = QCOW2_OPT_DISCARD_OTHER,
388 .type = QEMU_OPT_BOOL,
389 .help = "Generate discard requests when other clusters are freed",
392 .name = QCOW2_OPT_OVERLAP,
393 .type = QEMU_OPT_STRING,
394 .help = "Selects which overlap checks to perform from a range of "
395 "templates (none, constant, cached, all)",
398 .name = QCOW2_OPT_OVERLAP_TEMPLATE,
399 .type = QEMU_OPT_STRING,
400 .help = "Selects which overlap checks to perform from a range of "
401 "templates (none, constant, cached, all)",
404 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER,
405 .type = QEMU_OPT_BOOL,
406 .help = "Check for unintended writes into the main qcow2 header",
409 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1,
410 .type = QEMU_OPT_BOOL,
411 .help = "Check for unintended writes into the active L1 table",
414 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2,
415 .type = QEMU_OPT_BOOL,
416 .help = "Check for unintended writes into an active L2 table",
419 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
420 .type = QEMU_OPT_BOOL,
421 .help = "Check for unintended writes into the refcount table",
424 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
425 .type = QEMU_OPT_BOOL,
426 .help = "Check for unintended writes into a refcount block",
429 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
430 .type = QEMU_OPT_BOOL,
431 .help = "Check for unintended writes into the snapshot table",
434 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1,
435 .type = QEMU_OPT_BOOL,
436 .help = "Check for unintended writes into an inactive L1 table",
439 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2,
440 .type = QEMU_OPT_BOOL,
441 .help = "Check for unintended writes into an inactive L2 table",
444 .name = QCOW2_OPT_CACHE_SIZE,
445 .type = QEMU_OPT_SIZE,
446 .help = "Maximum combined metadata (L2 tables and refcount blocks) "
447 "cache size",
450 .name = QCOW2_OPT_L2_CACHE_SIZE,
451 .type = QEMU_OPT_SIZE,
452 .help = "Maximum L2 table cache size",
455 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE,
456 .type = QEMU_OPT_SIZE,
457 .help = "Maximum refcount block cache size",
460 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL,
461 .type = QEMU_OPT_NUMBER,
462 .help = "Clean unused cache entries after this time (in seconds)",
464 { /* end of list */ }
468 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = {
469 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER,
470 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1,
471 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2,
472 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
473 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
474 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
475 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1,
476 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2,
479 static void cache_clean_timer_cb(void *opaque)
481 BlockDriverState *bs = opaque;
482 BDRVQcow2State *s = bs->opaque;
483 qcow2_cache_clean_unused(bs, s->l2_table_cache);
484 qcow2_cache_clean_unused(bs, s->refcount_block_cache);
485 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
486 (int64_t) s->cache_clean_interval * 1000);
489 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context)
491 BDRVQcow2State *s = bs->opaque;
492 if (s->cache_clean_interval > 0) {
493 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL,
494 SCALE_MS, cache_clean_timer_cb,
495 bs);
496 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
497 (int64_t) s->cache_clean_interval * 1000);
501 static void cache_clean_timer_del(BlockDriverState *bs)
503 BDRVQcow2State *s = bs->opaque;
504 if (s->cache_clean_timer) {
505 timer_del(s->cache_clean_timer);
506 timer_free(s->cache_clean_timer);
507 s->cache_clean_timer = NULL;
511 static void qcow2_detach_aio_context(BlockDriverState *bs)
513 cache_clean_timer_del(bs);
516 static void qcow2_attach_aio_context(BlockDriverState *bs,
517 AioContext *new_context)
519 cache_clean_timer_init(bs, new_context);
522 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
523 uint64_t *l2_cache_size,
524 uint64_t *refcount_cache_size, Error **errp)
526 BDRVQcow2State *s = bs->opaque;
527 uint64_t combined_cache_size;
528 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set;
530 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE);
531 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE);
532 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
534 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0);
535 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0);
536 *refcount_cache_size = qemu_opt_get_size(opts,
537 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0);
539 if (combined_cache_size_set) {
540 if (l2_cache_size_set && refcount_cache_size_set) {
541 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE
542 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set "
543 "the same time");
544 return;
545 } else if (*l2_cache_size > combined_cache_size) {
546 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed "
547 QCOW2_OPT_CACHE_SIZE);
548 return;
549 } else if (*refcount_cache_size > combined_cache_size) {
550 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed "
551 QCOW2_OPT_CACHE_SIZE);
552 return;
555 if (l2_cache_size_set) {
556 *refcount_cache_size = combined_cache_size - *l2_cache_size;
557 } else if (refcount_cache_size_set) {
558 *l2_cache_size = combined_cache_size - *refcount_cache_size;
559 } else {
560 *refcount_cache_size = combined_cache_size
561 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1);
562 *l2_cache_size = combined_cache_size - *refcount_cache_size;
564 } else {
565 if (!l2_cache_size_set && !refcount_cache_size_set) {
566 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE,
567 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS
568 * s->cluster_size);
569 *refcount_cache_size = *l2_cache_size
570 / DEFAULT_L2_REFCOUNT_SIZE_RATIO;
571 } else if (!l2_cache_size_set) {
572 *l2_cache_size = *refcount_cache_size
573 * DEFAULT_L2_REFCOUNT_SIZE_RATIO;
574 } else if (!refcount_cache_size_set) {
575 *refcount_cache_size = *l2_cache_size
576 / DEFAULT_L2_REFCOUNT_SIZE_RATIO;
581 typedef struct Qcow2ReopenState {
582 Qcow2Cache *l2_table_cache;
583 Qcow2Cache *refcount_block_cache;
584 bool use_lazy_refcounts;
585 int overlap_check;
586 bool discard_passthrough[QCOW2_DISCARD_MAX];
587 uint64_t cache_clean_interval;
588 } Qcow2ReopenState;
590 static int qcow2_update_options_prepare(BlockDriverState *bs,
591 Qcow2ReopenState *r,
592 QDict *options, int flags,
593 Error **errp)
595 BDRVQcow2State *s = bs->opaque;
596 QemuOpts *opts = NULL;
597 const char *opt_overlap_check, *opt_overlap_check_template;
598 int overlap_check_template = 0;
599 uint64_t l2_cache_size, refcount_cache_size;
600 int i;
601 Error *local_err = NULL;
602 int ret;
604 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort);
605 qemu_opts_absorb_qdict(opts, options, &local_err);
606 if (local_err) {
607 error_propagate(errp, local_err);
608 ret = -EINVAL;
609 goto fail;
612 /* get L2 table/refcount block cache size from command line options */
613 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size,
614 &local_err);
615 if (local_err) {
616 error_propagate(errp, local_err);
617 ret = -EINVAL;
618 goto fail;
621 l2_cache_size /= s->cluster_size;
622 if (l2_cache_size < MIN_L2_CACHE_SIZE) {
623 l2_cache_size = MIN_L2_CACHE_SIZE;
625 if (l2_cache_size > INT_MAX) {
626 error_setg(errp, "L2 cache size too big");
627 ret = -EINVAL;
628 goto fail;
631 refcount_cache_size /= s->cluster_size;
632 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) {
633 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE;
635 if (refcount_cache_size > INT_MAX) {
636 error_setg(errp, "Refcount cache size too big");
637 ret = -EINVAL;
638 goto fail;
641 /* alloc new L2 table/refcount block cache, flush old one */
642 if (s->l2_table_cache) {
643 ret = qcow2_cache_flush(bs, s->l2_table_cache);
644 if (ret) {
645 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache");
646 goto fail;
650 if (s->refcount_block_cache) {
651 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
652 if (ret) {
653 error_setg_errno(errp, -ret,
654 "Failed to flush the refcount block cache");
655 goto fail;
659 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size);
660 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size);
661 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) {
662 error_setg(errp, "Could not allocate metadata caches");
663 ret = -ENOMEM;
664 goto fail;
667 /* New interval for cache cleanup timer */
668 r->cache_clean_interval =
669 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL,
670 s->cache_clean_interval);
671 if (r->cache_clean_interval > UINT_MAX) {
672 error_setg(errp, "Cache clean interval too big");
673 ret = -EINVAL;
674 goto fail;
677 /* lazy-refcounts; flush if going from enabled to disabled */
678 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
679 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
680 if (r->use_lazy_refcounts && s->qcow_version < 3) {
681 error_setg(errp, "Lazy refcounts require a qcow2 image with at least "
682 "qemu 1.1 compatibility level");
683 ret = -EINVAL;
684 goto fail;
687 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) {
688 ret = qcow2_mark_clean(bs);
689 if (ret < 0) {
690 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts");
691 goto fail;
695 /* Overlap check options */
696 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP);
697 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE);
698 if (opt_overlap_check_template && opt_overlap_check &&
699 strcmp(opt_overlap_check_template, opt_overlap_check))
701 error_setg(errp, "Conflicting values for qcow2 options '"
702 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
703 "' ('%s')", opt_overlap_check, opt_overlap_check_template);
704 ret = -EINVAL;
705 goto fail;
707 if (!opt_overlap_check) {
708 opt_overlap_check = opt_overlap_check_template ?: "cached";
711 if (!strcmp(opt_overlap_check, "none")) {
712 overlap_check_template = 0;
713 } else if (!strcmp(opt_overlap_check, "constant")) {
714 overlap_check_template = QCOW2_OL_CONSTANT;
715 } else if (!strcmp(opt_overlap_check, "cached")) {
716 overlap_check_template = QCOW2_OL_CACHED;
717 } else if (!strcmp(opt_overlap_check, "all")) {
718 overlap_check_template = QCOW2_OL_ALL;
719 } else {
720 error_setg(errp, "Unsupported value '%s' for qcow2 option "
721 "'overlap-check'. Allowed are any of the following: "
722 "none, constant, cached, all", opt_overlap_check);
723 ret = -EINVAL;
724 goto fail;
727 r->overlap_check = 0;
728 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) {
729 /* overlap-check defines a template bitmask, but every flag may be
730 * overwritten through the associated boolean option */
731 r->overlap_check |=
732 qemu_opt_get_bool(opts, overlap_bool_option_names[i],
733 overlap_check_template & (1 << i)) << i;
736 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
737 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
738 r->discard_passthrough[QCOW2_DISCARD_REQUEST] =
739 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST,
740 flags & BDRV_O_UNMAP);
741 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
742 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true);
743 r->discard_passthrough[QCOW2_DISCARD_OTHER] =
744 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false);
746 ret = 0;
747 fail:
748 qemu_opts_del(opts);
749 opts = NULL;
750 return ret;
753 static void qcow2_update_options_commit(BlockDriverState *bs,
754 Qcow2ReopenState *r)
756 BDRVQcow2State *s = bs->opaque;
757 int i;
759 if (s->l2_table_cache) {
760 qcow2_cache_destroy(bs, s->l2_table_cache);
762 if (s->refcount_block_cache) {
763 qcow2_cache_destroy(bs, s->refcount_block_cache);
765 s->l2_table_cache = r->l2_table_cache;
766 s->refcount_block_cache = r->refcount_block_cache;
768 s->overlap_check = r->overlap_check;
769 s->use_lazy_refcounts = r->use_lazy_refcounts;
771 for (i = 0; i < QCOW2_DISCARD_MAX; i++) {
772 s->discard_passthrough[i] = r->discard_passthrough[i];
775 if (s->cache_clean_interval != r->cache_clean_interval) {
776 cache_clean_timer_del(bs);
777 s->cache_clean_interval = r->cache_clean_interval;
778 cache_clean_timer_init(bs, bdrv_get_aio_context(bs));
782 static void qcow2_update_options_abort(BlockDriverState *bs,
783 Qcow2ReopenState *r)
785 if (r->l2_table_cache) {
786 qcow2_cache_destroy(bs, r->l2_table_cache);
788 if (r->refcount_block_cache) {
789 qcow2_cache_destroy(bs, r->refcount_block_cache);
793 static int qcow2_update_options(BlockDriverState *bs, QDict *options,
794 int flags, Error **errp)
796 Qcow2ReopenState r = {};
797 int ret;
799 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp);
800 if (ret >= 0) {
801 qcow2_update_options_commit(bs, &r);
802 } else {
803 qcow2_update_options_abort(bs, &r);
806 return ret;
809 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
810 Error **errp)
812 BDRVQcow2State *s = bs->opaque;
813 unsigned int len, i;
814 int ret = 0;
815 QCowHeader header;
816 Error *local_err = NULL;
817 uint64_t ext_end;
818 uint64_t l1_vm_state_index;
820 ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
821 if (ret < 0) {
822 error_setg_errno(errp, -ret, "Could not read qcow2 header");
823 goto fail;
825 be32_to_cpus(&header.magic);
826 be32_to_cpus(&header.version);
827 be64_to_cpus(&header.backing_file_offset);
828 be32_to_cpus(&header.backing_file_size);
829 be64_to_cpus(&header.size);
830 be32_to_cpus(&header.cluster_bits);
831 be32_to_cpus(&header.crypt_method);
832 be64_to_cpus(&header.l1_table_offset);
833 be32_to_cpus(&header.l1_size);
834 be64_to_cpus(&header.refcount_table_offset);
835 be32_to_cpus(&header.refcount_table_clusters);
836 be64_to_cpus(&header.snapshots_offset);
837 be32_to_cpus(&header.nb_snapshots);
839 if (header.magic != QCOW_MAGIC) {
840 error_setg(errp, "Image is not in qcow2 format");
841 ret = -EINVAL;
842 goto fail;
844 if (header.version < 2 || header.version > 3) {
845 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version);
846 ret = -ENOTSUP;
847 goto fail;
850 s->qcow_version = header.version;
852 /* Initialise cluster size */
853 if (header.cluster_bits < MIN_CLUSTER_BITS ||
854 header.cluster_bits > MAX_CLUSTER_BITS) {
855 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32,
856 header.cluster_bits);
857 ret = -EINVAL;
858 goto fail;
861 s->cluster_bits = header.cluster_bits;
862 s->cluster_size = 1 << s->cluster_bits;
863 s->cluster_sectors = 1 << (s->cluster_bits - 9);
865 /* Initialise version 3 header fields */
866 if (header.version == 2) {
867 header.incompatible_features = 0;
868 header.compatible_features = 0;
869 header.autoclear_features = 0;
870 header.refcount_order = 4;
871 header.header_length = 72;
872 } else {
873 be64_to_cpus(&header.incompatible_features);
874 be64_to_cpus(&header.compatible_features);
875 be64_to_cpus(&header.autoclear_features);
876 be32_to_cpus(&header.refcount_order);
877 be32_to_cpus(&header.header_length);
879 if (header.header_length < 104) {
880 error_setg(errp, "qcow2 header too short");
881 ret = -EINVAL;
882 goto fail;
886 if (header.header_length > s->cluster_size) {
887 error_setg(errp, "qcow2 header exceeds cluster size");
888 ret = -EINVAL;
889 goto fail;
892 if (header.header_length > sizeof(header)) {
893 s->unknown_header_fields_size = header.header_length - sizeof(header);
894 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size);
895 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields,
896 s->unknown_header_fields_size);
897 if (ret < 0) {
898 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header "
899 "fields");
900 goto fail;
904 if (header.backing_file_offset > s->cluster_size) {
905 error_setg(errp, "Invalid backing file offset");
906 ret = -EINVAL;
907 goto fail;
910 if (header.backing_file_offset) {
911 ext_end = header.backing_file_offset;
912 } else {
913 ext_end = 1 << header.cluster_bits;
916 /* Handle feature bits */
917 s->incompatible_features = header.incompatible_features;
918 s->compatible_features = header.compatible_features;
919 s->autoclear_features = header.autoclear_features;
921 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
922 void *feature_table = NULL;
923 qcow2_read_extensions(bs, header.header_length, ext_end,
924 &feature_table, NULL);
925 report_unsupported_feature(errp, feature_table,
926 s->incompatible_features &
927 ~QCOW2_INCOMPAT_MASK);
928 ret = -ENOTSUP;
929 g_free(feature_table);
930 goto fail;
933 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
934 /* Corrupt images may not be written to unless they are being repaired
936 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
937 error_setg(errp, "qcow2: Image is corrupt; cannot be opened "
938 "read/write");
939 ret = -EACCES;
940 goto fail;
944 /* Check support for various header values */
945 if (header.refcount_order > 6) {
946 error_setg(errp, "Reference count entry width too large; may not "
947 "exceed 64 bits");
948 ret = -EINVAL;
949 goto fail;
951 s->refcount_order = header.refcount_order;
952 s->refcount_bits = 1 << s->refcount_order;
953 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1);
954 s->refcount_max += s->refcount_max - 1;
956 if (header.crypt_method > QCOW_CRYPT_AES) {
957 error_setg(errp, "Unsupported encryption method: %" PRIu32,
958 header.crypt_method);
959 ret = -EINVAL;
960 goto fail;
962 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128,
963 QCRYPTO_CIPHER_MODE_CBC)) {
964 error_setg(errp, "AES cipher not available");
965 ret = -EINVAL;
966 goto fail;
968 s->crypt_method_header = header.crypt_method;
969 if (s->crypt_method_header) {
970 if (bdrv_uses_whitelist() &&
971 s->crypt_method_header == QCOW_CRYPT_AES) {
972 error_setg(errp,
973 "Use of AES-CBC encrypted qcow2 images is no longer "
974 "supported in system emulators");
975 error_append_hint(errp,
976 "You can use 'qemu-img convert' to convert your "
977 "image to an alternative supported format, such "
978 "as unencrypted qcow2, or raw with the LUKS "
979 "format instead.\n");
980 ret = -ENOSYS;
981 goto fail;
984 bs->encrypted = true;
987 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
988 s->l2_size = 1 << s->l2_bits;
989 /* 2^(s->refcount_order - 3) is the refcount width in bytes */
990 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3);
991 s->refcount_block_size = 1 << s->refcount_block_bits;
992 bs->total_sectors = header.size / 512;
993 s->csize_shift = (62 - (s->cluster_bits - 8));
994 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
995 s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
997 s->refcount_table_offset = header.refcount_table_offset;
998 s->refcount_table_size =
999 header.refcount_table_clusters << (s->cluster_bits - 3);
1001 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) {
1002 error_setg(errp, "Reference count table too large");
1003 ret = -EINVAL;
1004 goto fail;
1007 ret = validate_table_offset(bs, s->refcount_table_offset,
1008 s->refcount_table_size, sizeof(uint64_t));
1009 if (ret < 0) {
1010 error_setg(errp, "Invalid reference count table offset");
1011 goto fail;
1014 /* Snapshot table offset/length */
1015 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) {
1016 error_setg(errp, "Too many snapshots");
1017 ret = -EINVAL;
1018 goto fail;
1021 ret = validate_table_offset(bs, header.snapshots_offset,
1022 header.nb_snapshots,
1023 sizeof(QCowSnapshotHeader));
1024 if (ret < 0) {
1025 error_setg(errp, "Invalid snapshot table offset");
1026 goto fail;
1029 /* read the level 1 table */
1030 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
1031 error_setg(errp, "Active L1 table too large");
1032 ret = -EFBIG;
1033 goto fail;
1035 s->l1_size = header.l1_size;
1037 l1_vm_state_index = size_to_l1(s, header.size);
1038 if (l1_vm_state_index > INT_MAX) {
1039 error_setg(errp, "Image is too big");
1040 ret = -EFBIG;
1041 goto fail;
1043 s->l1_vm_state_index = l1_vm_state_index;
1045 /* the L1 table must contain at least enough entries to put
1046 header.size bytes */
1047 if (s->l1_size < s->l1_vm_state_index) {
1048 error_setg(errp, "L1 table is too small");
1049 ret = -EINVAL;
1050 goto fail;
1053 ret = validate_table_offset(bs, header.l1_table_offset,
1054 header.l1_size, sizeof(uint64_t));
1055 if (ret < 0) {
1056 error_setg(errp, "Invalid L1 table offset");
1057 goto fail;
1059 s->l1_table_offset = header.l1_table_offset;
1062 if (s->l1_size > 0) {
1063 s->l1_table = qemu_try_blockalign(bs->file->bs,
1064 align_offset(s->l1_size * sizeof(uint64_t), 512));
1065 if (s->l1_table == NULL) {
1066 error_setg(errp, "Could not allocate L1 table");
1067 ret = -ENOMEM;
1068 goto fail;
1070 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
1071 s->l1_size * sizeof(uint64_t));
1072 if (ret < 0) {
1073 error_setg_errno(errp, -ret, "Could not read L1 table");
1074 goto fail;
1076 for(i = 0;i < s->l1_size; i++) {
1077 be64_to_cpus(&s->l1_table[i]);
1081 /* Parse driver-specific options */
1082 ret = qcow2_update_options(bs, options, flags, errp);
1083 if (ret < 0) {
1084 goto fail;
1087 s->cluster_cache = g_malloc(s->cluster_size);
1088 /* one more sector for decompressed data alignment */
1089 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS
1090 * s->cluster_size + 512);
1091 if (s->cluster_data == NULL) {
1092 error_setg(errp, "Could not allocate temporary cluster buffer");
1093 ret = -ENOMEM;
1094 goto fail;
1097 s->cluster_cache_offset = -1;
1098 s->flags = flags;
1100 ret = qcow2_refcount_init(bs);
1101 if (ret != 0) {
1102 error_setg_errno(errp, -ret, "Could not initialize refcount handling");
1103 goto fail;
1106 QLIST_INIT(&s->cluster_allocs);
1107 QTAILQ_INIT(&s->discards);
1109 /* read qcow2 extensions */
1110 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL,
1111 &local_err)) {
1112 error_propagate(errp, local_err);
1113 ret = -EINVAL;
1114 goto fail;
1117 /* read the backing file name */
1118 if (header.backing_file_offset != 0) {
1119 len = header.backing_file_size;
1120 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) ||
1121 len >= sizeof(bs->backing_file)) {
1122 error_setg(errp, "Backing file name too long");
1123 ret = -EINVAL;
1124 goto fail;
1126 ret = bdrv_pread(bs->file, header.backing_file_offset,
1127 bs->backing_file, len);
1128 if (ret < 0) {
1129 error_setg_errno(errp, -ret, "Could not read backing file name");
1130 goto fail;
1132 bs->backing_file[len] = '\0';
1133 s->image_backing_file = g_strdup(bs->backing_file);
1136 /* Internal snapshots */
1137 s->snapshots_offset = header.snapshots_offset;
1138 s->nb_snapshots = header.nb_snapshots;
1140 ret = qcow2_read_snapshots(bs);
1141 if (ret < 0) {
1142 error_setg_errno(errp, -ret, "Could not read snapshots");
1143 goto fail;
1146 /* Clear unknown autoclear feature bits */
1147 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) {
1148 s->autoclear_features = 0;
1149 ret = qcow2_update_header(bs);
1150 if (ret < 0) {
1151 error_setg_errno(errp, -ret, "Could not update qcow2 header");
1152 goto fail;
1156 /* Initialise locks */
1157 qemu_co_mutex_init(&s->lock);
1159 /* Repair image if dirty */
1160 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only &&
1161 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) {
1162 BdrvCheckResult result = {0};
1164 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS);
1165 if (ret < 0) {
1166 error_setg_errno(errp, -ret, "Could not repair dirty image");
1167 goto fail;
1171 #ifdef DEBUG_ALLOC
1173 BdrvCheckResult result = {0};
1174 qcow2_check_refcounts(bs, &result, 0);
1176 #endif
1177 return ret;
1179 fail:
1180 g_free(s->unknown_header_fields);
1181 cleanup_unknown_header_ext(bs);
1182 qcow2_free_snapshots(bs);
1183 qcow2_refcount_close(bs);
1184 qemu_vfree(s->l1_table);
1185 /* else pre-write overlap checks in cache_destroy may crash */
1186 s->l1_table = NULL;
1187 cache_clean_timer_del(bs);
1188 if (s->l2_table_cache) {
1189 qcow2_cache_destroy(bs, s->l2_table_cache);
1191 if (s->refcount_block_cache) {
1192 qcow2_cache_destroy(bs, s->refcount_block_cache);
1194 g_free(s->cluster_cache);
1195 qemu_vfree(s->cluster_data);
1196 return ret;
1199 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp)
1201 BDRVQcow2State *s = bs->opaque;
1203 if (bs->encrypted) {
1204 /* Encryption works on a sector granularity */
1205 bs->bl.request_alignment = BDRV_SECTOR_SIZE;
1207 bs->bl.pwrite_zeroes_alignment = s->cluster_size;
1210 static int qcow2_set_key(BlockDriverState *bs, const char *key)
1212 BDRVQcow2State *s = bs->opaque;
1213 uint8_t keybuf[16];
1214 int len, i;
1215 Error *err = NULL;
1217 memset(keybuf, 0, 16);
1218 len = strlen(key);
1219 if (len > 16)
1220 len = 16;
1221 /* XXX: we could compress the chars to 7 bits to increase
1222 entropy */
1223 for(i = 0;i < len;i++) {
1224 keybuf[i] = key[i];
1226 assert(bs->encrypted);
1228 qcrypto_cipher_free(s->cipher);
1229 s->cipher = qcrypto_cipher_new(
1230 QCRYPTO_CIPHER_ALG_AES_128,
1231 QCRYPTO_CIPHER_MODE_CBC,
1232 keybuf, G_N_ELEMENTS(keybuf),
1233 &err);
1235 if (!s->cipher) {
1236 /* XXX would be nice if errors in this method could
1237 * be properly propagate to the caller. Would need
1238 * the bdrv_set_key() API signature to be fixed. */
1239 error_free(err);
1240 return -1;
1242 return 0;
1245 static int qcow2_reopen_prepare(BDRVReopenState *state,
1246 BlockReopenQueue *queue, Error **errp)
1248 Qcow2ReopenState *r;
1249 int ret;
1251 r = g_new0(Qcow2ReopenState, 1);
1252 state->opaque = r;
1254 ret = qcow2_update_options_prepare(state->bs, r, state->options,
1255 state->flags, errp);
1256 if (ret < 0) {
1257 goto fail;
1260 /* We need to write out any unwritten data if we reopen read-only. */
1261 if ((state->flags & BDRV_O_RDWR) == 0) {
1262 ret = bdrv_flush(state->bs);
1263 if (ret < 0) {
1264 goto fail;
1267 ret = qcow2_mark_clean(state->bs);
1268 if (ret < 0) {
1269 goto fail;
1273 return 0;
1275 fail:
1276 qcow2_update_options_abort(state->bs, r);
1277 g_free(r);
1278 return ret;
1281 static void qcow2_reopen_commit(BDRVReopenState *state)
1283 qcow2_update_options_commit(state->bs, state->opaque);
1284 g_free(state->opaque);
1287 static void qcow2_reopen_abort(BDRVReopenState *state)
1289 qcow2_update_options_abort(state->bs, state->opaque);
1290 g_free(state->opaque);
1293 static void qcow2_join_options(QDict *options, QDict *old_options)
1295 bool has_new_overlap_template =
1296 qdict_haskey(options, QCOW2_OPT_OVERLAP) ||
1297 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE);
1298 bool has_new_total_cache_size =
1299 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE);
1300 bool has_all_cache_options;
1302 /* New overlap template overrides all old overlap options */
1303 if (has_new_overlap_template) {
1304 qdict_del(old_options, QCOW2_OPT_OVERLAP);
1305 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE);
1306 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER);
1307 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1);
1308 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2);
1309 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE);
1310 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK);
1311 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE);
1312 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1);
1313 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2);
1316 /* New total cache size overrides all old options */
1317 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) {
1318 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE);
1319 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
1322 qdict_join(options, old_options, false);
1325 * If after merging all cache size options are set, an old total size is
1326 * overwritten. Do keep all options, however, if all three are new. The
1327 * resulting error message is what we want to happen.
1329 has_all_cache_options =
1330 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) ||
1331 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) ||
1332 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
1334 if (has_all_cache_options && !has_new_total_cache_size) {
1335 qdict_del(options, QCOW2_OPT_CACHE_SIZE);
1339 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs,
1340 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file)
1342 BDRVQcow2State *s = bs->opaque;
1343 uint64_t cluster_offset;
1344 int index_in_cluster, ret;
1345 unsigned int bytes;
1346 int64_t status = 0;
1348 bytes = MIN(INT_MAX, nb_sectors * BDRV_SECTOR_SIZE);
1349 qemu_co_mutex_lock(&s->lock);
1350 ret = qcow2_get_cluster_offset(bs, sector_num << 9, &bytes,
1351 &cluster_offset);
1352 qemu_co_mutex_unlock(&s->lock);
1353 if (ret < 0) {
1354 return ret;
1357 *pnum = bytes >> BDRV_SECTOR_BITS;
1359 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED &&
1360 !s->cipher) {
1361 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1362 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
1363 *file = bs->file->bs;
1364 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset;
1366 if (ret == QCOW2_CLUSTER_ZERO) {
1367 status |= BDRV_BLOCK_ZERO;
1368 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) {
1369 status |= BDRV_BLOCK_DATA;
1371 return status;
1374 /* handle reading after the end of the backing file */
1375 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
1376 int64_t offset, int bytes)
1378 uint64_t bs_size = bs->total_sectors * BDRV_SECTOR_SIZE;
1379 int n1;
1381 if ((offset + bytes) <= bs_size) {
1382 return bytes;
1385 if (offset >= bs_size) {
1386 n1 = 0;
1387 } else {
1388 n1 = bs_size - offset;
1391 qemu_iovec_memset(qiov, n1, 0, bytes - n1);
1393 return n1;
1396 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
1397 uint64_t bytes, QEMUIOVector *qiov,
1398 int flags)
1400 BDRVQcow2State *s = bs->opaque;
1401 int offset_in_cluster, n1;
1402 int ret;
1403 unsigned int cur_bytes; /* number of bytes in current iteration */
1404 uint64_t cluster_offset = 0;
1405 uint64_t bytes_done = 0;
1406 QEMUIOVector hd_qiov;
1407 uint8_t *cluster_data = NULL;
1409 qemu_iovec_init(&hd_qiov, qiov->niov);
1411 qemu_co_mutex_lock(&s->lock);
1413 while (bytes != 0) {
1415 /* prepare next request */
1416 cur_bytes = MIN(bytes, INT_MAX);
1417 if (s->cipher) {
1418 cur_bytes = MIN(cur_bytes,
1419 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
1422 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset);
1423 if (ret < 0) {
1424 goto fail;
1427 offset_in_cluster = offset_into_cluster(s, offset);
1429 qemu_iovec_reset(&hd_qiov);
1430 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
1432 switch (ret) {
1433 case QCOW2_CLUSTER_UNALLOCATED:
1435 if (bs->backing) {
1436 /* read from the base image */
1437 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov,
1438 offset, cur_bytes);
1439 if (n1 > 0) {
1440 QEMUIOVector local_qiov;
1442 qemu_iovec_init(&local_qiov, hd_qiov.niov);
1443 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, n1);
1445 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
1446 qemu_co_mutex_unlock(&s->lock);
1447 ret = bdrv_co_preadv(bs->backing, offset, n1,
1448 &local_qiov, 0);
1449 qemu_co_mutex_lock(&s->lock);
1451 qemu_iovec_destroy(&local_qiov);
1453 if (ret < 0) {
1454 goto fail;
1457 } else {
1458 /* Note: in this case, no need to wait */
1459 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
1461 break;
1463 case QCOW2_CLUSTER_ZERO:
1464 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
1465 break;
1467 case QCOW2_CLUSTER_COMPRESSED:
1468 /* add AIO support for compressed blocks ? */
1469 ret = qcow2_decompress_cluster(bs, cluster_offset);
1470 if (ret < 0) {
1471 goto fail;
1474 qemu_iovec_from_buf(&hd_qiov, 0,
1475 s->cluster_cache + offset_in_cluster,
1476 cur_bytes);
1477 break;
1479 case QCOW2_CLUSTER_NORMAL:
1480 if ((cluster_offset & 511) != 0) {
1481 ret = -EIO;
1482 goto fail;
1485 if (bs->encrypted) {
1486 assert(s->cipher);
1489 * For encrypted images, read everything into a temporary
1490 * contiguous buffer on which the AES functions can work.
1492 if (!cluster_data) {
1493 cluster_data =
1494 qemu_try_blockalign(bs->file->bs,
1495 QCOW_MAX_CRYPT_CLUSTERS
1496 * s->cluster_size);
1497 if (cluster_data == NULL) {
1498 ret = -ENOMEM;
1499 goto fail;
1503 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
1504 qemu_iovec_reset(&hd_qiov);
1505 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
1508 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
1509 qemu_co_mutex_unlock(&s->lock);
1510 ret = bdrv_co_preadv(bs->file,
1511 cluster_offset + offset_in_cluster,
1512 cur_bytes, &hd_qiov, 0);
1513 qemu_co_mutex_lock(&s->lock);
1514 if (ret < 0) {
1515 goto fail;
1517 if (bs->encrypted) {
1518 assert(s->cipher);
1519 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
1520 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
1521 Error *err = NULL;
1522 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS,
1523 cluster_data, cluster_data,
1524 cur_bytes >> BDRV_SECTOR_BITS,
1525 false, &err) < 0) {
1526 error_free(err);
1527 ret = -EIO;
1528 goto fail;
1530 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes);
1532 break;
1534 default:
1535 g_assert_not_reached();
1536 ret = -EIO;
1537 goto fail;
1540 bytes -= cur_bytes;
1541 offset += cur_bytes;
1542 bytes_done += cur_bytes;
1544 ret = 0;
1546 fail:
1547 qemu_co_mutex_unlock(&s->lock);
1549 qemu_iovec_destroy(&hd_qiov);
1550 qemu_vfree(cluster_data);
1552 return ret;
1555 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
1556 uint64_t bytes, QEMUIOVector *qiov,
1557 int flags)
1559 BDRVQcow2State *s = bs->opaque;
1560 int offset_in_cluster;
1561 int ret;
1562 unsigned int cur_bytes; /* number of sectors in current iteration */
1563 uint64_t cluster_offset;
1564 QEMUIOVector hd_qiov;
1565 uint64_t bytes_done = 0;
1566 uint8_t *cluster_data = NULL;
1567 QCowL2Meta *l2meta = NULL;
1569 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes);
1571 qemu_iovec_init(&hd_qiov, qiov->niov);
1573 s->cluster_cache_offset = -1; /* disable compressed cache */
1575 qemu_co_mutex_lock(&s->lock);
1577 while (bytes != 0) {
1579 l2meta = NULL;
1581 trace_qcow2_writev_start_part(qemu_coroutine_self());
1582 offset_in_cluster = offset_into_cluster(s, offset);
1583 cur_bytes = MIN(bytes, INT_MAX);
1584 if (bs->encrypted) {
1585 cur_bytes = MIN(cur_bytes,
1586 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
1587 - offset_in_cluster);
1590 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes,
1591 &cluster_offset, &l2meta);
1592 if (ret < 0) {
1593 goto fail;
1596 assert((cluster_offset & 511) == 0);
1598 qemu_iovec_reset(&hd_qiov);
1599 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
1601 if (bs->encrypted) {
1602 Error *err = NULL;
1603 assert(s->cipher);
1604 if (!cluster_data) {
1605 cluster_data = qemu_try_blockalign(bs->file->bs,
1606 QCOW_MAX_CRYPT_CLUSTERS
1607 * s->cluster_size);
1608 if (cluster_data == NULL) {
1609 ret = -ENOMEM;
1610 goto fail;
1614 assert(hd_qiov.size <=
1615 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
1616 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
1618 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS,
1619 cluster_data, cluster_data,
1620 cur_bytes >>BDRV_SECTOR_BITS,
1621 true, &err) < 0) {
1622 error_free(err);
1623 ret = -EIO;
1624 goto fail;
1627 qemu_iovec_reset(&hd_qiov);
1628 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
1631 ret = qcow2_pre_write_overlap_check(bs, 0,
1632 cluster_offset + offset_in_cluster, cur_bytes);
1633 if (ret < 0) {
1634 goto fail;
1637 qemu_co_mutex_unlock(&s->lock);
1638 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
1639 trace_qcow2_writev_data(qemu_coroutine_self(),
1640 cluster_offset + offset_in_cluster);
1641 ret = bdrv_co_pwritev(bs->file,
1642 cluster_offset + offset_in_cluster,
1643 cur_bytes, &hd_qiov, 0);
1644 qemu_co_mutex_lock(&s->lock);
1645 if (ret < 0) {
1646 goto fail;
1649 while (l2meta != NULL) {
1650 QCowL2Meta *next;
1652 ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
1653 if (ret < 0) {
1654 goto fail;
1657 /* Take the request off the list of running requests */
1658 if (l2meta->nb_clusters != 0) {
1659 QLIST_REMOVE(l2meta, next_in_flight);
1662 qemu_co_queue_restart_all(&l2meta->dependent_requests);
1664 next = l2meta->next;
1665 g_free(l2meta);
1666 l2meta = next;
1669 bytes -= cur_bytes;
1670 offset += cur_bytes;
1671 bytes_done += cur_bytes;
1672 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes);
1674 ret = 0;
1676 fail:
1677 qemu_co_mutex_unlock(&s->lock);
1679 while (l2meta != NULL) {
1680 QCowL2Meta *next;
1682 if (l2meta->nb_clusters != 0) {
1683 QLIST_REMOVE(l2meta, next_in_flight);
1685 qemu_co_queue_restart_all(&l2meta->dependent_requests);
1687 next = l2meta->next;
1688 g_free(l2meta);
1689 l2meta = next;
1692 qemu_iovec_destroy(&hd_qiov);
1693 qemu_vfree(cluster_data);
1694 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
1696 return ret;
1699 static int qcow2_inactivate(BlockDriverState *bs)
1701 BDRVQcow2State *s = bs->opaque;
1702 int ret, result = 0;
1704 ret = qcow2_cache_flush(bs, s->l2_table_cache);
1705 if (ret) {
1706 result = ret;
1707 error_report("Failed to flush the L2 table cache: %s",
1708 strerror(-ret));
1711 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
1712 if (ret) {
1713 result = ret;
1714 error_report("Failed to flush the refcount block cache: %s",
1715 strerror(-ret));
1718 if (result == 0) {
1719 qcow2_mark_clean(bs);
1722 return result;
1725 static void qcow2_close(BlockDriverState *bs)
1727 BDRVQcow2State *s = bs->opaque;
1728 qemu_vfree(s->l1_table);
1729 /* else pre-write overlap checks in cache_destroy may crash */
1730 s->l1_table = NULL;
1732 if (!(s->flags & BDRV_O_INACTIVE)) {
1733 qcow2_inactivate(bs);
1736 cache_clean_timer_del(bs);
1737 qcow2_cache_destroy(bs, s->l2_table_cache);
1738 qcow2_cache_destroy(bs, s->refcount_block_cache);
1740 qcrypto_cipher_free(s->cipher);
1741 s->cipher = NULL;
1743 g_free(s->unknown_header_fields);
1744 cleanup_unknown_header_ext(bs);
1746 g_free(s->image_backing_file);
1747 g_free(s->image_backing_format);
1749 g_free(s->cluster_cache);
1750 qemu_vfree(s->cluster_data);
1751 qcow2_refcount_close(bs);
1752 qcow2_free_snapshots(bs);
1755 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp)
1757 BDRVQcow2State *s = bs->opaque;
1758 int flags = s->flags;
1759 QCryptoCipher *cipher = NULL;
1760 QDict *options;
1761 Error *local_err = NULL;
1762 int ret;
1765 * Backing files are read-only which makes all of their metadata immutable,
1766 * that means we don't have to worry about reopening them here.
1769 cipher = s->cipher;
1770 s->cipher = NULL;
1772 qcow2_close(bs);
1774 memset(s, 0, sizeof(BDRVQcow2State));
1775 options = qdict_clone_shallow(bs->options);
1777 flags &= ~BDRV_O_INACTIVE;
1778 ret = qcow2_open(bs, options, flags, &local_err);
1779 QDECREF(options);
1780 if (local_err) {
1781 error_propagate(errp, local_err);
1782 error_prepend(errp, "Could not reopen qcow2 layer: ");
1783 bs->drv = NULL;
1784 return;
1785 } else if (ret < 0) {
1786 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer");
1787 bs->drv = NULL;
1788 return;
1791 s->cipher = cipher;
1794 static size_t header_ext_add(char *buf, uint32_t magic, const void *s,
1795 size_t len, size_t buflen)
1797 QCowExtension *ext_backing_fmt = (QCowExtension*) buf;
1798 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7);
1800 if (buflen < ext_len) {
1801 return -ENOSPC;
1804 *ext_backing_fmt = (QCowExtension) {
1805 .magic = cpu_to_be32(magic),
1806 .len = cpu_to_be32(len),
1809 if (len) {
1810 memcpy(buf + sizeof(QCowExtension), s, len);
1813 return ext_len;
1817 * Updates the qcow2 header, including the variable length parts of it, i.e.
1818 * the backing file name and all extensions. qcow2 was not designed to allow
1819 * such changes, so if we run out of space (we can only use the first cluster)
1820 * this function may fail.
1822 * Returns 0 on success, -errno in error cases.
1824 int qcow2_update_header(BlockDriverState *bs)
1826 BDRVQcow2State *s = bs->opaque;
1827 QCowHeader *header;
1828 char *buf;
1829 size_t buflen = s->cluster_size;
1830 int ret;
1831 uint64_t total_size;
1832 uint32_t refcount_table_clusters;
1833 size_t header_length;
1834 Qcow2UnknownHeaderExtension *uext;
1836 buf = qemu_blockalign(bs, buflen);
1838 /* Header structure */
1839 header = (QCowHeader*) buf;
1841 if (buflen < sizeof(*header)) {
1842 ret = -ENOSPC;
1843 goto fail;
1846 header_length = sizeof(*header) + s->unknown_header_fields_size;
1847 total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
1848 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
1850 *header = (QCowHeader) {
1851 /* Version 2 fields */
1852 .magic = cpu_to_be32(QCOW_MAGIC),
1853 .version = cpu_to_be32(s->qcow_version),
1854 .backing_file_offset = 0,
1855 .backing_file_size = 0,
1856 .cluster_bits = cpu_to_be32(s->cluster_bits),
1857 .size = cpu_to_be64(total_size),
1858 .crypt_method = cpu_to_be32(s->crypt_method_header),
1859 .l1_size = cpu_to_be32(s->l1_size),
1860 .l1_table_offset = cpu_to_be64(s->l1_table_offset),
1861 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset),
1862 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters),
1863 .nb_snapshots = cpu_to_be32(s->nb_snapshots),
1864 .snapshots_offset = cpu_to_be64(s->snapshots_offset),
1866 /* Version 3 fields */
1867 .incompatible_features = cpu_to_be64(s->incompatible_features),
1868 .compatible_features = cpu_to_be64(s->compatible_features),
1869 .autoclear_features = cpu_to_be64(s->autoclear_features),
1870 .refcount_order = cpu_to_be32(s->refcount_order),
1871 .header_length = cpu_to_be32(header_length),
1874 /* For older versions, write a shorter header */
1875 switch (s->qcow_version) {
1876 case 2:
1877 ret = offsetof(QCowHeader, incompatible_features);
1878 break;
1879 case 3:
1880 ret = sizeof(*header);
1881 break;
1882 default:
1883 ret = -EINVAL;
1884 goto fail;
1887 buf += ret;
1888 buflen -= ret;
1889 memset(buf, 0, buflen);
1891 /* Preserve any unknown field in the header */
1892 if (s->unknown_header_fields_size) {
1893 if (buflen < s->unknown_header_fields_size) {
1894 ret = -ENOSPC;
1895 goto fail;
1898 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size);
1899 buf += s->unknown_header_fields_size;
1900 buflen -= s->unknown_header_fields_size;
1903 /* Backing file format header extension */
1904 if (s->image_backing_format) {
1905 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT,
1906 s->image_backing_format,
1907 strlen(s->image_backing_format),
1908 buflen);
1909 if (ret < 0) {
1910 goto fail;
1913 buf += ret;
1914 buflen -= ret;
1917 /* Feature table */
1918 if (s->qcow_version >= 3) {
1919 Qcow2Feature features[] = {
1921 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
1922 .bit = QCOW2_INCOMPAT_DIRTY_BITNR,
1923 .name = "dirty bit",
1926 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
1927 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR,
1928 .name = "corrupt bit",
1931 .type = QCOW2_FEAT_TYPE_COMPATIBLE,
1932 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
1933 .name = "lazy refcounts",
1937 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
1938 features, sizeof(features), buflen);
1939 if (ret < 0) {
1940 goto fail;
1942 buf += ret;
1943 buflen -= ret;
1946 /* Keep unknown header extensions */
1947 QLIST_FOREACH(uext, &s->unknown_header_ext, next) {
1948 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen);
1949 if (ret < 0) {
1950 goto fail;
1953 buf += ret;
1954 buflen -= ret;
1957 /* End of header extensions */
1958 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen);
1959 if (ret < 0) {
1960 goto fail;
1963 buf += ret;
1964 buflen -= ret;
1966 /* Backing file name */
1967 if (s->image_backing_file) {
1968 size_t backing_file_len = strlen(s->image_backing_file);
1970 if (buflen < backing_file_len) {
1971 ret = -ENOSPC;
1972 goto fail;
1975 /* Using strncpy is ok here, since buf is not NUL-terminated. */
1976 strncpy(buf, s->image_backing_file, buflen);
1978 header->backing_file_offset = cpu_to_be64(buf - ((char*) header));
1979 header->backing_file_size = cpu_to_be32(backing_file_len);
1982 /* Write the new header */
1983 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size);
1984 if (ret < 0) {
1985 goto fail;
1988 ret = 0;
1989 fail:
1990 qemu_vfree(header);
1991 return ret;
1994 static int qcow2_change_backing_file(BlockDriverState *bs,
1995 const char *backing_file, const char *backing_fmt)
1997 BDRVQcow2State *s = bs->opaque;
1999 if (backing_file && strlen(backing_file) > 1023) {
2000 return -EINVAL;
2003 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
2004 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
2006 g_free(s->image_backing_file);
2007 g_free(s->image_backing_format);
2009 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL;
2010 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL;
2012 return qcow2_update_header(bs);
2015 static int preallocate(BlockDriverState *bs)
2017 uint64_t bytes;
2018 uint64_t offset;
2019 uint64_t host_offset = 0;
2020 unsigned int cur_bytes;
2021 int ret;
2022 QCowL2Meta *meta;
2024 bytes = bdrv_getlength(bs);
2025 offset = 0;
2027 while (bytes) {
2028 cur_bytes = MIN(bytes, INT_MAX);
2029 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes,
2030 &host_offset, &meta);
2031 if (ret < 0) {
2032 return ret;
2035 while (meta) {
2036 QCowL2Meta *next = meta->next;
2038 ret = qcow2_alloc_cluster_link_l2(bs, meta);
2039 if (ret < 0) {
2040 qcow2_free_any_clusters(bs, meta->alloc_offset,
2041 meta->nb_clusters, QCOW2_DISCARD_NEVER);
2042 return ret;
2045 /* There are no dependent requests, but we need to remove our
2046 * request from the list of in-flight requests */
2047 QLIST_REMOVE(meta, next_in_flight);
2049 g_free(meta);
2050 meta = next;
2053 /* TODO Preallocate data if requested */
2055 bytes -= cur_bytes;
2056 offset += cur_bytes;
2060 * It is expected that the image file is large enough to actually contain
2061 * all of the allocated clusters (otherwise we get failing reads after
2062 * EOF). Extend the image to the last allocated sector.
2064 if (host_offset != 0) {
2065 uint8_t data = 0;
2066 ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1,
2067 &data, 1);
2068 if (ret < 0) {
2069 return ret;
2073 return 0;
2076 static int qcow2_create2(const char *filename, int64_t total_size,
2077 const char *backing_file, const char *backing_format,
2078 int flags, size_t cluster_size, PreallocMode prealloc,
2079 QemuOpts *opts, int version, int refcount_order,
2080 Error **errp)
2082 int cluster_bits;
2083 QDict *options;
2085 /* Calculate cluster_bits */
2086 cluster_bits = ctz32(cluster_size);
2087 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
2088 (1 << cluster_bits) != cluster_size)
2090 error_setg(errp, "Cluster size must be a power of two between %d and "
2091 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
2092 return -EINVAL;
2096 * Open the image file and write a minimal qcow2 header.
2098 * We keep things simple and start with a zero-sized image. We also
2099 * do without refcount blocks or a L1 table for now. We'll fix the
2100 * inconsistency later.
2102 * We do need a refcount table because growing the refcount table means
2103 * allocating two new refcount blocks - the seconds of which would be at
2104 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
2105 * size for any qcow2 image.
2107 BlockBackend *blk;
2108 QCowHeader *header;
2109 uint64_t* refcount_table;
2110 Error *local_err = NULL;
2111 int ret;
2113 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
2114 /* Note: The following calculation does not need to be exact; if it is a
2115 * bit off, either some bytes will be "leaked" (which is fine) or we
2116 * will need to increase the file size by some bytes (which is fine,
2117 * too, as long as the bulk is allocated here). Therefore, using
2118 * floating point arithmetic is fine. */
2119 int64_t meta_size = 0;
2120 uint64_t nreftablee, nrefblocke, nl1e, nl2e;
2121 int64_t aligned_total_size = align_offset(total_size, cluster_size);
2122 int refblock_bits, refblock_size;
2123 /* refcount entry size in bytes */
2124 double rces = (1 << refcount_order) / 8.;
2126 /* see qcow2_open() */
2127 refblock_bits = cluster_bits - (refcount_order - 3);
2128 refblock_size = 1 << refblock_bits;
2130 /* header: 1 cluster */
2131 meta_size += cluster_size;
2133 /* total size of L2 tables */
2134 nl2e = aligned_total_size / cluster_size;
2135 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
2136 meta_size += nl2e * sizeof(uint64_t);
2138 /* total size of L1 tables */
2139 nl1e = nl2e * sizeof(uint64_t) / cluster_size;
2140 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t));
2141 meta_size += nl1e * sizeof(uint64_t);
2143 /* total size of refcount blocks
2145 * note: every host cluster is reference-counted, including metadata
2146 * (even refcount blocks are recursively included).
2147 * Let:
2148 * a = total_size (this is the guest disk size)
2149 * m = meta size not including refcount blocks and refcount tables
2150 * c = cluster size
2151 * y1 = number of refcount blocks entries
2152 * y2 = meta size including everything
2153 * rces = refcount entry size in bytes
2154 * then,
2155 * y1 = (y2 + a)/c
2156 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m
2157 * we can get y1:
2158 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c)
2160 nrefblocke = (aligned_total_size + meta_size + cluster_size)
2161 / (cluster_size - rces - rces * sizeof(uint64_t)
2162 / cluster_size);
2163 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size;
2165 /* total size of refcount tables */
2166 nreftablee = nrefblocke / refblock_size;
2167 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t));
2168 meta_size += nreftablee * sizeof(uint64_t);
2170 qemu_opt_set_number(opts, BLOCK_OPT_SIZE,
2171 aligned_total_size + meta_size, &error_abort);
2172 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc],
2173 &error_abort);
2176 ret = bdrv_create_file(filename, opts, &local_err);
2177 if (ret < 0) {
2178 error_propagate(errp, local_err);
2179 return ret;
2182 blk = blk_new_open(filename, NULL, NULL,
2183 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
2184 if (blk == NULL) {
2185 error_propagate(errp, local_err);
2186 return -EIO;
2189 blk_set_allow_write_beyond_eof(blk, true);
2191 /* Write the header */
2192 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header));
2193 header = g_malloc0(cluster_size);
2194 *header = (QCowHeader) {
2195 .magic = cpu_to_be32(QCOW_MAGIC),
2196 .version = cpu_to_be32(version),
2197 .cluster_bits = cpu_to_be32(cluster_bits),
2198 .size = cpu_to_be64(0),
2199 .l1_table_offset = cpu_to_be64(0),
2200 .l1_size = cpu_to_be32(0),
2201 .refcount_table_offset = cpu_to_be64(cluster_size),
2202 .refcount_table_clusters = cpu_to_be32(1),
2203 .refcount_order = cpu_to_be32(refcount_order),
2204 .header_length = cpu_to_be32(sizeof(*header)),
2207 if (flags & BLOCK_FLAG_ENCRYPT) {
2208 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
2209 } else {
2210 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
2213 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) {
2214 header->compatible_features |=
2215 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS);
2218 ret = blk_pwrite(blk, 0, header, cluster_size, 0);
2219 g_free(header);
2220 if (ret < 0) {
2221 error_setg_errno(errp, -ret, "Could not write qcow2 header");
2222 goto out;
2225 /* Write a refcount table with one refcount block */
2226 refcount_table = g_malloc0(2 * cluster_size);
2227 refcount_table[0] = cpu_to_be64(2 * cluster_size);
2228 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0);
2229 g_free(refcount_table);
2231 if (ret < 0) {
2232 error_setg_errno(errp, -ret, "Could not write refcount table");
2233 goto out;
2236 blk_unref(blk);
2237 blk = NULL;
2240 * And now open the image and make it consistent first (i.e. increase the
2241 * refcount of the cluster that is occupied by the header and the refcount
2242 * table)
2244 options = qdict_new();
2245 qdict_put(options, "driver", qstring_from_str("qcow2"));
2246 blk = blk_new_open(filename, NULL, options,
2247 BDRV_O_RDWR | BDRV_O_NO_FLUSH, &local_err);
2248 if (blk == NULL) {
2249 error_propagate(errp, local_err);
2250 ret = -EIO;
2251 goto out;
2254 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size);
2255 if (ret < 0) {
2256 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 "
2257 "header and refcount table");
2258 goto out;
2260 } else if (ret != 0) {
2261 error_report("Huh, first cluster in empty image is already in use?");
2262 abort();
2265 /* Create a full header (including things like feature table) */
2266 ret = qcow2_update_header(blk_bs(blk));
2267 if (ret < 0) {
2268 error_setg_errno(errp, -ret, "Could not update qcow2 header");
2269 goto out;
2272 /* Okay, now that we have a valid image, let's give it the right size */
2273 ret = blk_truncate(blk, total_size);
2274 if (ret < 0) {
2275 error_setg_errno(errp, -ret, "Could not resize image");
2276 goto out;
2279 /* Want a backing file? There you go.*/
2280 if (backing_file) {
2281 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format);
2282 if (ret < 0) {
2283 error_setg_errno(errp, -ret, "Could not assign backing file '%s' "
2284 "with format '%s'", backing_file, backing_format);
2285 goto out;
2289 /* And if we're supposed to preallocate metadata, do that now */
2290 if (prealloc != PREALLOC_MODE_OFF) {
2291 BDRVQcow2State *s = blk_bs(blk)->opaque;
2292 qemu_co_mutex_lock(&s->lock);
2293 ret = preallocate(blk_bs(blk));
2294 qemu_co_mutex_unlock(&s->lock);
2295 if (ret < 0) {
2296 error_setg_errno(errp, -ret, "Could not preallocate metadata");
2297 goto out;
2301 blk_unref(blk);
2302 blk = NULL;
2304 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */
2305 options = qdict_new();
2306 qdict_put(options, "driver", qstring_from_str("qcow2"));
2307 blk = blk_new_open(filename, NULL, options,
2308 BDRV_O_RDWR | BDRV_O_NO_BACKING, &local_err);
2309 if (blk == NULL) {
2310 error_propagate(errp, local_err);
2311 ret = -EIO;
2312 goto out;
2315 ret = 0;
2316 out:
2317 if (blk) {
2318 blk_unref(blk);
2320 return ret;
2323 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
2325 char *backing_file = NULL;
2326 char *backing_fmt = NULL;
2327 char *buf = NULL;
2328 uint64_t size = 0;
2329 int flags = 0;
2330 size_t cluster_size = DEFAULT_CLUSTER_SIZE;
2331 PreallocMode prealloc;
2332 int version = 3;
2333 uint64_t refcount_bits = 16;
2334 int refcount_order;
2335 Error *local_err = NULL;
2336 int ret;
2338 /* Read out options */
2339 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
2340 BDRV_SECTOR_SIZE);
2341 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
2342 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
2343 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
2344 flags |= BLOCK_FLAG_ENCRYPT;
2346 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
2347 DEFAULT_CLUSTER_SIZE);
2348 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
2349 prealloc = qapi_enum_parse(PreallocMode_lookup, buf,
2350 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF,
2351 &local_err);
2352 if (local_err) {
2353 error_propagate(errp, local_err);
2354 ret = -EINVAL;
2355 goto finish;
2357 g_free(buf);
2358 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL);
2359 if (!buf) {
2360 /* keep the default */
2361 } else if (!strcmp(buf, "0.10")) {
2362 version = 2;
2363 } else if (!strcmp(buf, "1.1")) {
2364 version = 3;
2365 } else {
2366 error_setg(errp, "Invalid compatibility level: '%s'", buf);
2367 ret = -EINVAL;
2368 goto finish;
2371 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) {
2372 flags |= BLOCK_FLAG_LAZY_REFCOUNTS;
2375 if (backing_file && prealloc != PREALLOC_MODE_OFF) {
2376 error_setg(errp, "Backing file and preallocation cannot be used at "
2377 "the same time");
2378 ret = -EINVAL;
2379 goto finish;
2382 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) {
2383 error_setg(errp, "Lazy refcounts only supported with compatibility "
2384 "level 1.1 and above (use compat=1.1 or greater)");
2385 ret = -EINVAL;
2386 goto finish;
2389 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS,
2390 refcount_bits);
2391 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) {
2392 error_setg(errp, "Refcount width must be a power of two and may not "
2393 "exceed 64 bits");
2394 ret = -EINVAL;
2395 goto finish;
2398 if (version < 3 && refcount_bits != 16) {
2399 error_setg(errp, "Different refcount widths than 16 bits require "
2400 "compatibility level 1.1 or above (use compat=1.1 or "
2401 "greater)");
2402 ret = -EINVAL;
2403 goto finish;
2406 refcount_order = ctz32(refcount_bits);
2408 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags,
2409 cluster_size, prealloc, opts, version, refcount_order,
2410 &local_err);
2411 error_propagate(errp, local_err);
2413 finish:
2414 g_free(backing_file);
2415 g_free(backing_fmt);
2416 g_free(buf);
2417 return ret;
2421 static bool is_zero_sectors(BlockDriverState *bs, int64_t start,
2422 uint32_t count)
2424 int nr;
2425 BlockDriverState *file;
2426 int64_t res;
2428 if (!count) {
2429 return true;
2431 res = bdrv_get_block_status_above(bs, NULL, start, count,
2432 &nr, &file);
2433 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count;
2436 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
2437 int64_t offset, int count, BdrvRequestFlags flags)
2439 int ret;
2440 BDRVQcow2State *s = bs->opaque;
2442 uint32_t head = offset % s->cluster_size;
2443 uint32_t tail = (offset + count) % s->cluster_size;
2445 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, count);
2447 if (head || tail) {
2448 int64_t cl_start = (offset - head) >> BDRV_SECTOR_BITS;
2449 uint64_t off;
2450 unsigned int nr;
2452 assert(head + count <= s->cluster_size);
2454 /* check whether remainder of cluster already reads as zero */
2455 if (!(is_zero_sectors(bs, cl_start,
2456 DIV_ROUND_UP(head, BDRV_SECTOR_SIZE)) &&
2457 is_zero_sectors(bs, (offset + count) >> BDRV_SECTOR_BITS,
2458 DIV_ROUND_UP(-tail & (s->cluster_size - 1),
2459 BDRV_SECTOR_SIZE)))) {
2460 return -ENOTSUP;
2463 qemu_co_mutex_lock(&s->lock);
2464 /* We can have new write after previous check */
2465 offset = cl_start << BDRV_SECTOR_BITS;
2466 count = s->cluster_size;
2467 nr = s->cluster_size;
2468 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off);
2469 if (ret != QCOW2_CLUSTER_UNALLOCATED && ret != QCOW2_CLUSTER_ZERO) {
2470 qemu_co_mutex_unlock(&s->lock);
2471 return -ENOTSUP;
2473 } else {
2474 qemu_co_mutex_lock(&s->lock);
2477 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, count);
2479 /* Whatever is left can use real zero clusters */
2480 ret = qcow2_zero_clusters(bs, offset, count >> BDRV_SECTOR_BITS);
2481 qemu_co_mutex_unlock(&s->lock);
2483 return ret;
2486 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs,
2487 int64_t offset, int count)
2489 int ret;
2490 BDRVQcow2State *s = bs->opaque;
2492 qemu_co_mutex_lock(&s->lock);
2493 ret = qcow2_discard_clusters(bs, offset, count >> BDRV_SECTOR_BITS,
2494 QCOW2_DISCARD_REQUEST, false);
2495 qemu_co_mutex_unlock(&s->lock);
2496 return ret;
2499 static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
2501 BDRVQcow2State *s = bs->opaque;
2502 int64_t new_l1_size;
2503 int ret;
2505 if (offset & 511) {
2506 error_report("The new size must be a multiple of 512");
2507 return -EINVAL;
2510 /* cannot proceed if image has snapshots */
2511 if (s->nb_snapshots) {
2512 error_report("Can't resize an image which has snapshots");
2513 return -ENOTSUP;
2516 /* shrinking is currently not supported */
2517 if (offset < bs->total_sectors * 512) {
2518 error_report("qcow2 doesn't support shrinking images yet");
2519 return -ENOTSUP;
2522 new_l1_size = size_to_l1(s, offset);
2523 ret = qcow2_grow_l1_table(bs, new_l1_size, true);
2524 if (ret < 0) {
2525 return ret;
2528 /* write updated header.size */
2529 offset = cpu_to_be64(offset);
2530 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
2531 &offset, sizeof(uint64_t));
2532 if (ret < 0) {
2533 return ret;
2536 s->l1_vm_state_index = new_l1_size;
2537 return 0;
2540 /* XXX: put compressed sectors first, then all the cluster aligned
2541 tables to avoid losing bytes in alignment */
2542 static coroutine_fn int
2543 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
2544 uint64_t bytes, QEMUIOVector *qiov)
2546 BDRVQcow2State *s = bs->opaque;
2547 QEMUIOVector hd_qiov;
2548 struct iovec iov;
2549 z_stream strm;
2550 int ret, out_len;
2551 uint8_t *buf, *out_buf;
2552 uint64_t cluster_offset;
2554 if (bytes == 0) {
2555 /* align end of file to a sector boundary to ease reading with
2556 sector based I/Os */
2557 cluster_offset = bdrv_getlength(bs->file->bs);
2558 return bdrv_truncate(bs->file->bs, cluster_offset);
2561 buf = qemu_blockalign(bs, s->cluster_size);
2562 if (bytes != s->cluster_size) {
2563 if (bytes > s->cluster_size ||
2564 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
2566 qemu_vfree(buf);
2567 return -EINVAL;
2569 /* Zero-pad last write if image size is not cluster aligned */
2570 memset(buf + bytes, 0, s->cluster_size - bytes);
2572 qemu_iovec_to_buf(qiov, 0, buf, bytes);
2574 out_buf = g_malloc(s->cluster_size);
2576 /* best compression, small window, no zlib header */
2577 memset(&strm, 0, sizeof(strm));
2578 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
2579 Z_DEFLATED, -12,
2580 9, Z_DEFAULT_STRATEGY);
2581 if (ret != 0) {
2582 ret = -EINVAL;
2583 goto fail;
2586 strm.avail_in = s->cluster_size;
2587 strm.next_in = (uint8_t *)buf;
2588 strm.avail_out = s->cluster_size;
2589 strm.next_out = out_buf;
2591 ret = deflate(&strm, Z_FINISH);
2592 if (ret != Z_STREAM_END && ret != Z_OK) {
2593 deflateEnd(&strm);
2594 ret = -EINVAL;
2595 goto fail;
2597 out_len = strm.next_out - out_buf;
2599 deflateEnd(&strm);
2601 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
2602 /* could not compress: write normal cluster */
2603 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0);
2604 if (ret < 0) {
2605 goto fail;
2607 goto success;
2610 qemu_co_mutex_lock(&s->lock);
2611 cluster_offset =
2612 qcow2_alloc_compressed_cluster_offset(bs, offset, out_len);
2613 if (!cluster_offset) {
2614 qemu_co_mutex_unlock(&s->lock);
2615 ret = -EIO;
2616 goto fail;
2618 cluster_offset &= s->cluster_offset_mask;
2620 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len);
2621 qemu_co_mutex_unlock(&s->lock);
2622 if (ret < 0) {
2623 goto fail;
2626 iov = (struct iovec) {
2627 .iov_base = out_buf,
2628 .iov_len = out_len,
2630 qemu_iovec_init_external(&hd_qiov, &iov, 1);
2632 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
2633 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0);
2634 if (ret < 0) {
2635 goto fail;
2637 success:
2638 ret = 0;
2639 fail:
2640 qemu_vfree(buf);
2641 g_free(out_buf);
2642 return ret;
2645 static int make_completely_empty(BlockDriverState *bs)
2647 BDRVQcow2State *s = bs->opaque;
2648 int ret, l1_clusters;
2649 int64_t offset;
2650 uint64_t *new_reftable = NULL;
2651 uint64_t rt_entry, l1_size2;
2652 struct {
2653 uint64_t l1_offset;
2654 uint64_t reftable_offset;
2655 uint32_t reftable_clusters;
2656 } QEMU_PACKED l1_ofs_rt_ofs_cls;
2658 ret = qcow2_cache_empty(bs, s->l2_table_cache);
2659 if (ret < 0) {
2660 goto fail;
2663 ret = qcow2_cache_empty(bs, s->refcount_block_cache);
2664 if (ret < 0) {
2665 goto fail;
2668 /* Refcounts will be broken utterly */
2669 ret = qcow2_mark_dirty(bs);
2670 if (ret < 0) {
2671 goto fail;
2674 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
2676 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
2677 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t);
2679 /* After this call, neither the in-memory nor the on-disk refcount
2680 * information accurately describe the actual references */
2682 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset,
2683 l1_clusters * s->cluster_size, 0);
2684 if (ret < 0) {
2685 goto fail_broken_refcounts;
2687 memset(s->l1_table, 0, l1_size2);
2689 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE);
2691 /* Overwrite enough clusters at the beginning of the sectors to place
2692 * the refcount table, a refcount block and the L1 table in; this may
2693 * overwrite parts of the existing refcount and L1 table, which is not
2694 * an issue because the dirty flag is set, complete data loss is in fact
2695 * desired and partial data loss is consequently fine as well */
2696 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size,
2697 (2 + l1_clusters) * s->cluster_size, 0);
2698 /* This call (even if it failed overall) may have overwritten on-disk
2699 * refcount structures; in that case, the in-memory refcount information
2700 * will probably differ from the on-disk information which makes the BDS
2701 * unusable */
2702 if (ret < 0) {
2703 goto fail_broken_refcounts;
2706 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
2707 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE);
2709 /* "Create" an empty reftable (one cluster) directly after the image
2710 * header and an empty L1 table three clusters after the image header;
2711 * the cluster between those two will be used as the first refblock */
2712 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size);
2713 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size);
2714 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1);
2715 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset),
2716 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls));
2717 if (ret < 0) {
2718 goto fail_broken_refcounts;
2721 s->l1_table_offset = 3 * s->cluster_size;
2723 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t));
2724 if (!new_reftable) {
2725 ret = -ENOMEM;
2726 goto fail_broken_refcounts;
2729 s->refcount_table_offset = s->cluster_size;
2730 s->refcount_table_size = s->cluster_size / sizeof(uint64_t);
2732 g_free(s->refcount_table);
2733 s->refcount_table = new_reftable;
2734 new_reftable = NULL;
2736 /* Now the in-memory refcount information again corresponds to the on-disk
2737 * information (reftable is empty and no refblocks (the refblock cache is
2738 * empty)); however, this means some clusters (e.g. the image header) are
2739 * referenced, but not refcounted, but the normal qcow2 code assumes that
2740 * the in-memory information is always correct */
2742 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
2744 /* Enter the first refblock into the reftable */
2745 rt_entry = cpu_to_be64(2 * s->cluster_size);
2746 ret = bdrv_pwrite_sync(bs->file, s->cluster_size,
2747 &rt_entry, sizeof(rt_entry));
2748 if (ret < 0) {
2749 goto fail_broken_refcounts;
2751 s->refcount_table[0] = 2 * s->cluster_size;
2753 s->free_cluster_index = 0;
2754 assert(3 + l1_clusters <= s->refcount_block_size);
2755 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2);
2756 if (offset < 0) {
2757 ret = offset;
2758 goto fail_broken_refcounts;
2759 } else if (offset > 0) {
2760 error_report("First cluster in emptied image is in use");
2761 abort();
2764 /* Now finally the in-memory information corresponds to the on-disk
2765 * structures and is correct */
2766 ret = qcow2_mark_clean(bs);
2767 if (ret < 0) {
2768 goto fail;
2771 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size);
2772 if (ret < 0) {
2773 goto fail;
2776 return 0;
2778 fail_broken_refcounts:
2779 /* The BDS is unusable at this point. If we wanted to make it usable, we
2780 * would have to call qcow2_refcount_close(), qcow2_refcount_init(),
2781 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
2782 * again. However, because the functions which could have caused this error
2783 * path to be taken are used by those functions as well, it's very likely
2784 * that that sequence will fail as well. Therefore, just eject the BDS. */
2785 bs->drv = NULL;
2787 fail:
2788 g_free(new_reftable);
2789 return ret;
2792 static int qcow2_make_empty(BlockDriverState *bs)
2794 BDRVQcow2State *s = bs->opaque;
2795 uint64_t start_sector;
2796 int sector_step = INT_MAX / BDRV_SECTOR_SIZE;
2797 int l1_clusters, ret = 0;
2799 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
2801 if (s->qcow_version >= 3 && !s->snapshots &&
2802 3 + l1_clusters <= s->refcount_block_size) {
2803 /* The following function only works for qcow2 v3 images (it requires
2804 * the dirty flag) and only as long as there are no snapshots (because
2805 * it completely empties the image). Furthermore, the L1 table and three
2806 * additional clusters (image header, refcount table, one refcount
2807 * block) have to fit inside one refcount block. */
2808 return make_completely_empty(bs);
2811 /* This fallback code simply discards every active cluster; this is slow,
2812 * but works in all cases */
2813 for (start_sector = 0; start_sector < bs->total_sectors;
2814 start_sector += sector_step)
2816 /* As this function is generally used after committing an external
2817 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
2818 * default action for this kind of discard is to pass the discard,
2819 * which will ideally result in an actually smaller image file, as
2820 * is probably desired. */
2821 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE,
2822 MIN(sector_step,
2823 bs->total_sectors - start_sector),
2824 QCOW2_DISCARD_SNAPSHOT, true);
2825 if (ret < 0) {
2826 break;
2830 return ret;
2833 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs)
2835 BDRVQcow2State *s = bs->opaque;
2836 int ret;
2838 qemu_co_mutex_lock(&s->lock);
2839 ret = qcow2_cache_write(bs, s->l2_table_cache);
2840 if (ret < 0) {
2841 qemu_co_mutex_unlock(&s->lock);
2842 return ret;
2845 if (qcow2_need_accurate_refcounts(s)) {
2846 ret = qcow2_cache_write(bs, s->refcount_block_cache);
2847 if (ret < 0) {
2848 qemu_co_mutex_unlock(&s->lock);
2849 return ret;
2852 qemu_co_mutex_unlock(&s->lock);
2854 return 0;
2857 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
2859 BDRVQcow2State *s = bs->opaque;
2860 bdi->unallocated_blocks_are_zero = true;
2861 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3);
2862 bdi->cluster_size = s->cluster_size;
2863 bdi->vm_state_offset = qcow2_vm_state_offset(s);
2864 return 0;
2867 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs)
2869 BDRVQcow2State *s = bs->opaque;
2870 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1);
2872 *spec_info = (ImageInfoSpecific){
2873 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2,
2874 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1),
2876 if (s->qcow_version == 2) {
2877 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
2878 .compat = g_strdup("0.10"),
2879 .refcount_bits = s->refcount_bits,
2881 } else if (s->qcow_version == 3) {
2882 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
2883 .compat = g_strdup("1.1"),
2884 .lazy_refcounts = s->compatible_features &
2885 QCOW2_COMPAT_LAZY_REFCOUNTS,
2886 .has_lazy_refcounts = true,
2887 .corrupt = s->incompatible_features &
2888 QCOW2_INCOMPAT_CORRUPT,
2889 .has_corrupt = true,
2890 .refcount_bits = s->refcount_bits,
2892 } else {
2893 /* if this assertion fails, this probably means a new version was
2894 * added without having it covered here */
2895 assert(false);
2898 return spec_info;
2901 #if 0
2902 static void dump_refcounts(BlockDriverState *bs)
2904 BDRVQcow2State *s = bs->opaque;
2905 int64_t nb_clusters, k, k1, size;
2906 int refcount;
2908 size = bdrv_getlength(bs->file->bs);
2909 nb_clusters = size_to_clusters(s, size);
2910 for(k = 0; k < nb_clusters;) {
2911 k1 = k;
2912 refcount = get_refcount(bs, k);
2913 k++;
2914 while (k < nb_clusters && get_refcount(bs, k) == refcount)
2915 k++;
2916 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount,
2917 k - k1);
2920 #endif
2922 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
2923 int64_t pos)
2925 BDRVQcow2State *s = bs->opaque;
2927 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
2928 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos,
2929 qiov->size, qiov, 0);
2932 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
2933 int64_t pos)
2935 BDRVQcow2State *s = bs->opaque;
2937 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
2938 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos,
2939 qiov->size, qiov, 0);
2943 * Downgrades an image's version. To achieve this, any incompatible features
2944 * have to be removed.
2946 static int qcow2_downgrade(BlockDriverState *bs, int target_version,
2947 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
2949 BDRVQcow2State *s = bs->opaque;
2950 int current_version = s->qcow_version;
2951 int ret;
2953 if (target_version == current_version) {
2954 return 0;
2955 } else if (target_version > current_version) {
2956 return -EINVAL;
2957 } else if (target_version != 2) {
2958 return -EINVAL;
2961 if (s->refcount_order != 4) {
2962 error_report("compat=0.10 requires refcount_bits=16");
2963 return -ENOTSUP;
2966 /* clear incompatible features */
2967 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
2968 ret = qcow2_mark_clean(bs);
2969 if (ret < 0) {
2970 return ret;
2974 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
2975 * the first place; if that happens nonetheless, returning -ENOTSUP is the
2976 * best thing to do anyway */
2978 if (s->incompatible_features) {
2979 return -ENOTSUP;
2982 /* since we can ignore compatible features, we can set them to 0 as well */
2983 s->compatible_features = 0;
2984 /* if lazy refcounts have been used, they have already been fixed through
2985 * clearing the dirty flag */
2987 /* clearing autoclear features is trivial */
2988 s->autoclear_features = 0;
2990 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque);
2991 if (ret < 0) {
2992 return ret;
2995 s->qcow_version = target_version;
2996 ret = qcow2_update_header(bs);
2997 if (ret < 0) {
2998 s->qcow_version = current_version;
2999 return ret;
3001 return 0;
3004 typedef enum Qcow2AmendOperation {
3005 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be
3006 * statically initialized to so that the helper CB can discern the first
3007 * invocation from an operation change */
3008 QCOW2_NO_OPERATION = 0,
3010 QCOW2_CHANGING_REFCOUNT_ORDER,
3011 QCOW2_DOWNGRADING,
3012 } Qcow2AmendOperation;
3014 typedef struct Qcow2AmendHelperCBInfo {
3015 /* The code coordinating the amend operations should only modify
3016 * these four fields; the rest will be managed by the CB */
3017 BlockDriverAmendStatusCB *original_status_cb;
3018 void *original_cb_opaque;
3020 Qcow2AmendOperation current_operation;
3022 /* Total number of operations to perform (only set once) */
3023 int total_operations;
3025 /* The following fields are managed by the CB */
3027 /* Number of operations completed */
3028 int operations_completed;
3030 /* Cumulative offset of all completed operations */
3031 int64_t offset_completed;
3033 Qcow2AmendOperation last_operation;
3034 int64_t last_work_size;
3035 } Qcow2AmendHelperCBInfo;
3037 static void qcow2_amend_helper_cb(BlockDriverState *bs,
3038 int64_t operation_offset,
3039 int64_t operation_work_size, void *opaque)
3041 Qcow2AmendHelperCBInfo *info = opaque;
3042 int64_t current_work_size;
3043 int64_t projected_work_size;
3045 if (info->current_operation != info->last_operation) {
3046 if (info->last_operation != QCOW2_NO_OPERATION) {
3047 info->offset_completed += info->last_work_size;
3048 info->operations_completed++;
3051 info->last_operation = info->current_operation;
3054 assert(info->total_operations > 0);
3055 assert(info->operations_completed < info->total_operations);
3057 info->last_work_size = operation_work_size;
3059 current_work_size = info->offset_completed + operation_work_size;
3061 /* current_work_size is the total work size for (operations_completed + 1)
3062 * operations (which includes this one), so multiply it by the number of
3063 * operations not covered and divide it by the number of operations
3064 * covered to get a projection for the operations not covered */
3065 projected_work_size = current_work_size * (info->total_operations -
3066 info->operations_completed - 1)
3067 / (info->operations_completed + 1);
3069 info->original_status_cb(bs, info->offset_completed + operation_offset,
3070 current_work_size + projected_work_size,
3071 info->original_cb_opaque);
3074 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
3075 BlockDriverAmendStatusCB *status_cb,
3076 void *cb_opaque)
3078 BDRVQcow2State *s = bs->opaque;
3079 int old_version = s->qcow_version, new_version = old_version;
3080 uint64_t new_size = 0;
3081 const char *backing_file = NULL, *backing_format = NULL;
3082 bool lazy_refcounts = s->use_lazy_refcounts;
3083 const char *compat = NULL;
3084 uint64_t cluster_size = s->cluster_size;
3085 bool encrypt;
3086 int refcount_bits = s->refcount_bits;
3087 int ret;
3088 QemuOptDesc *desc = opts->list->desc;
3089 Qcow2AmendHelperCBInfo helper_cb_info;
3091 while (desc && desc->name) {
3092 if (!qemu_opt_find(opts, desc->name)) {
3093 /* only change explicitly defined options */
3094 desc++;
3095 continue;
3098 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) {
3099 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL);
3100 if (!compat) {
3101 /* preserve default */
3102 } else if (!strcmp(compat, "0.10")) {
3103 new_version = 2;
3104 } else if (!strcmp(compat, "1.1")) {
3105 new_version = 3;
3106 } else {
3107 error_report("Unknown compatibility level %s", compat);
3108 return -EINVAL;
3110 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) {
3111 error_report("Cannot change preallocation mode");
3112 return -ENOTSUP;
3113 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) {
3114 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
3115 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) {
3116 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
3117 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) {
3118 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
3119 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) {
3120 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT,
3121 !!s->cipher);
3123 if (encrypt != !!s->cipher) {
3124 error_report("Changing the encryption flag is not supported");
3125 return -ENOTSUP;
3127 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) {
3128 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE,
3129 cluster_size);
3130 if (cluster_size != s->cluster_size) {
3131 error_report("Changing the cluster size is not supported");
3132 return -ENOTSUP;
3134 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) {
3135 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS,
3136 lazy_refcounts);
3137 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) {
3138 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS,
3139 refcount_bits);
3141 if (refcount_bits <= 0 || refcount_bits > 64 ||
3142 !is_power_of_2(refcount_bits))
3144 error_report("Refcount width must be a power of two and may "
3145 "not exceed 64 bits");
3146 return -EINVAL;
3148 } else {
3149 /* if this point is reached, this probably means a new option was
3150 * added without having it covered here */
3151 abort();
3154 desc++;
3157 helper_cb_info = (Qcow2AmendHelperCBInfo){
3158 .original_status_cb = status_cb,
3159 .original_cb_opaque = cb_opaque,
3160 .total_operations = (new_version < old_version)
3161 + (s->refcount_bits != refcount_bits)
3164 /* Upgrade first (some features may require compat=1.1) */
3165 if (new_version > old_version) {
3166 s->qcow_version = new_version;
3167 ret = qcow2_update_header(bs);
3168 if (ret < 0) {
3169 s->qcow_version = old_version;
3170 return ret;
3174 if (s->refcount_bits != refcount_bits) {
3175 int refcount_order = ctz32(refcount_bits);
3176 Error *local_error = NULL;
3178 if (new_version < 3 && refcount_bits != 16) {
3179 error_report("Different refcount widths than 16 bits require "
3180 "compatibility level 1.1 or above (use compat=1.1 or "
3181 "greater)");
3182 return -EINVAL;
3185 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER;
3186 ret = qcow2_change_refcount_order(bs, refcount_order,
3187 &qcow2_amend_helper_cb,
3188 &helper_cb_info, &local_error);
3189 if (ret < 0) {
3190 error_report_err(local_error);
3191 return ret;
3195 if (backing_file || backing_format) {
3196 ret = qcow2_change_backing_file(bs,
3197 backing_file ?: s->image_backing_file,
3198 backing_format ?: s->image_backing_format);
3199 if (ret < 0) {
3200 return ret;
3204 if (s->use_lazy_refcounts != lazy_refcounts) {
3205 if (lazy_refcounts) {
3206 if (new_version < 3) {
3207 error_report("Lazy refcounts only supported with compatibility "
3208 "level 1.1 and above (use compat=1.1 or greater)");
3209 return -EINVAL;
3211 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
3212 ret = qcow2_update_header(bs);
3213 if (ret < 0) {
3214 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
3215 return ret;
3217 s->use_lazy_refcounts = true;
3218 } else {
3219 /* make image clean first */
3220 ret = qcow2_mark_clean(bs);
3221 if (ret < 0) {
3222 return ret;
3224 /* now disallow lazy refcounts */
3225 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
3226 ret = qcow2_update_header(bs);
3227 if (ret < 0) {
3228 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
3229 return ret;
3231 s->use_lazy_refcounts = false;
3235 if (new_size) {
3236 ret = bdrv_truncate(bs, new_size);
3237 if (ret < 0) {
3238 return ret;
3242 /* Downgrade last (so unsupported features can be removed before) */
3243 if (new_version < old_version) {
3244 helper_cb_info.current_operation = QCOW2_DOWNGRADING;
3245 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb,
3246 &helper_cb_info);
3247 if (ret < 0) {
3248 return ret;
3252 return 0;
3256 * If offset or size are negative, respectively, they will not be included in
3257 * the BLOCK_IMAGE_CORRUPTED event emitted.
3258 * fatal will be ignored for read-only BDS; corruptions found there will always
3259 * be considered non-fatal.
3261 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
3262 int64_t size, const char *message_format, ...)
3264 BDRVQcow2State *s = bs->opaque;
3265 const char *node_name;
3266 char *message;
3267 va_list ap;
3269 fatal = fatal && !bs->read_only;
3271 if (s->signaled_corruption &&
3272 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
3274 return;
3277 va_start(ap, message_format);
3278 message = g_strdup_vprintf(message_format, ap);
3279 va_end(ap);
3281 if (fatal) {
3282 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further "
3283 "corruption events will be suppressed\n", message);
3284 } else {
3285 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal "
3286 "corruption events will be suppressed\n", message);
3289 node_name = bdrv_get_node_name(bs);
3290 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs),
3291 *node_name != '\0', node_name,
3292 message, offset >= 0, offset,
3293 size >= 0, size,
3294 fatal, &error_abort);
3295 g_free(message);
3297 if (fatal) {
3298 qcow2_mark_corrupt(bs);
3299 bs->drv = NULL; /* make BDS unusable */
3302 s->signaled_corruption = true;
3305 static QemuOptsList qcow2_create_opts = {
3306 .name = "qcow2-create-opts",
3307 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head),
3308 .desc = {
3310 .name = BLOCK_OPT_SIZE,
3311 .type = QEMU_OPT_SIZE,
3312 .help = "Virtual disk size"
3315 .name = BLOCK_OPT_COMPAT_LEVEL,
3316 .type = QEMU_OPT_STRING,
3317 .help = "Compatibility level (0.10 or 1.1)"
3320 .name = BLOCK_OPT_BACKING_FILE,
3321 .type = QEMU_OPT_STRING,
3322 .help = "File name of a base image"
3325 .name = BLOCK_OPT_BACKING_FMT,
3326 .type = QEMU_OPT_STRING,
3327 .help = "Image format of the base image"
3330 .name = BLOCK_OPT_ENCRYPT,
3331 .type = QEMU_OPT_BOOL,
3332 .help = "Encrypt the image",
3333 .def_value_str = "off"
3336 .name = BLOCK_OPT_CLUSTER_SIZE,
3337 .type = QEMU_OPT_SIZE,
3338 .help = "qcow2 cluster size",
3339 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE)
3342 .name = BLOCK_OPT_PREALLOC,
3343 .type = QEMU_OPT_STRING,
3344 .help = "Preallocation mode (allowed values: off, metadata, "
3345 "falloc, full)"
3348 .name = BLOCK_OPT_LAZY_REFCOUNTS,
3349 .type = QEMU_OPT_BOOL,
3350 .help = "Postpone refcount updates",
3351 .def_value_str = "off"
3354 .name = BLOCK_OPT_REFCOUNT_BITS,
3355 .type = QEMU_OPT_NUMBER,
3356 .help = "Width of a reference count entry in bits",
3357 .def_value_str = "16"
3359 { /* end of list */ }
3363 BlockDriver bdrv_qcow2 = {
3364 .format_name = "qcow2",
3365 .instance_size = sizeof(BDRVQcow2State),
3366 .bdrv_probe = qcow2_probe,
3367 .bdrv_open = qcow2_open,
3368 .bdrv_close = qcow2_close,
3369 .bdrv_reopen_prepare = qcow2_reopen_prepare,
3370 .bdrv_reopen_commit = qcow2_reopen_commit,
3371 .bdrv_reopen_abort = qcow2_reopen_abort,
3372 .bdrv_join_options = qcow2_join_options,
3373 .bdrv_create = qcow2_create,
3374 .bdrv_has_zero_init = bdrv_has_zero_init_1,
3375 .bdrv_co_get_block_status = qcow2_co_get_block_status,
3376 .bdrv_set_key = qcow2_set_key,
3378 .bdrv_co_preadv = qcow2_co_preadv,
3379 .bdrv_co_pwritev = qcow2_co_pwritev,
3380 .bdrv_co_flush_to_os = qcow2_co_flush_to_os,
3382 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes,
3383 .bdrv_co_pdiscard = qcow2_co_pdiscard,
3384 .bdrv_truncate = qcow2_truncate,
3385 .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed,
3386 .bdrv_make_empty = qcow2_make_empty,
3388 .bdrv_snapshot_create = qcow2_snapshot_create,
3389 .bdrv_snapshot_goto = qcow2_snapshot_goto,
3390 .bdrv_snapshot_delete = qcow2_snapshot_delete,
3391 .bdrv_snapshot_list = qcow2_snapshot_list,
3392 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp,
3393 .bdrv_get_info = qcow2_get_info,
3394 .bdrv_get_specific_info = qcow2_get_specific_info,
3396 .bdrv_save_vmstate = qcow2_save_vmstate,
3397 .bdrv_load_vmstate = qcow2_load_vmstate,
3399 .supports_backing = true,
3400 .bdrv_change_backing_file = qcow2_change_backing_file,
3402 .bdrv_refresh_limits = qcow2_refresh_limits,
3403 .bdrv_invalidate_cache = qcow2_invalidate_cache,
3404 .bdrv_inactivate = qcow2_inactivate,
3406 .create_opts = &qcow2_create_opts,
3407 .bdrv_check = qcow2_check,
3408 .bdrv_amend_options = qcow2_amend_options,
3410 .bdrv_detach_aio_context = qcow2_detach_aio_context,
3411 .bdrv_attach_aio_context = qcow2_attach_aio_context,
3414 static void bdrv_qcow2_init(void)
3416 bdrv_register(&bdrv_qcow2);
3419 block_init(bdrv_qcow2_init);