aspeed/smc: Remove 'num_cs' field
[qemu.git] / block / qcow2.c
blobc8115e1cba0f8ed09254f7889d38a338430a9ab5
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.
25 #include "qemu/osdep.h"
27 #include "block/qdict.h"
28 #include "sysemu/block-backend.h"
29 #include "qemu/main-loop.h"
30 #include "qemu/module.h"
31 #include "qcow2.h"
32 #include "qemu/error-report.h"
33 #include "qapi/error.h"
34 #include "qapi/qapi-events-block-core.h"
35 #include "qapi/qmp/qdict.h"
36 #include "qapi/qmp/qstring.h"
37 #include "trace.h"
38 #include "qemu/option_int.h"
39 #include "qemu/cutils.h"
40 #include "qemu/bswap.h"
41 #include "qapi/qobject-input-visitor.h"
42 #include "qapi/qapi-visit-block-core.h"
43 #include "crypto.h"
44 #include "block/aio_task.h"
47 Differences with QCOW:
49 - Support for multiple incremental snapshots.
50 - Memory management by reference counts.
51 - Clusters which have a reference count of one have the bit
52 QCOW_OFLAG_COPIED to optimize write performance.
53 - Size of compressed clusters is stored in sectors to reduce bit usage
54 in the cluster offsets.
55 - Support for storing additional data (such as the VM state) in the
56 snapshots.
57 - If a backing store is used, the cluster size is not constrained
58 (could be backported to QCOW).
59 - L2 tables have always a size of one cluster.
63 typedef struct {
64 uint32_t magic;
65 uint32_t len;
66 } QEMU_PACKED QCowExtension;
68 #define QCOW2_EXT_MAGIC_END 0
69 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xe2792aca
70 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
71 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77
72 #define QCOW2_EXT_MAGIC_BITMAPS 0x23852875
73 #define QCOW2_EXT_MAGIC_DATA_FILE 0x44415441
75 static int coroutine_fn
76 qcow2_co_preadv_compressed(BlockDriverState *bs,
77 uint64_t l2_entry,
78 uint64_t offset,
79 uint64_t bytes,
80 QEMUIOVector *qiov,
81 size_t qiov_offset);
83 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
85 const QCowHeader *cow_header = (const void *)buf;
87 if (buf_size >= sizeof(QCowHeader) &&
88 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
89 be32_to_cpu(cow_header->version) >= 2)
90 return 100;
91 else
92 return 0;
96 static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset,
97 uint8_t *buf, size_t buflen,
98 void *opaque, Error **errp)
100 BlockDriverState *bs = opaque;
101 BDRVQcow2State *s = bs->opaque;
102 ssize_t ret;
104 if ((offset + buflen) > s->crypto_header.length) {
105 error_setg(errp, "Request for data outside of extension header");
106 return -1;
109 ret = bdrv_pread(bs->file,
110 s->crypto_header.offset + offset, buf, buflen);
111 if (ret < 0) {
112 error_setg_errno(errp, -ret, "Could not read encryption header");
113 return -1;
115 return ret;
119 static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen,
120 void *opaque, Error **errp)
122 BlockDriverState *bs = opaque;
123 BDRVQcow2State *s = bs->opaque;
124 int64_t ret;
125 int64_t clusterlen;
127 ret = qcow2_alloc_clusters(bs, headerlen);
128 if (ret < 0) {
129 error_setg_errno(errp, -ret,
130 "Cannot allocate cluster for LUKS header size %zu",
131 headerlen);
132 return -1;
135 s->crypto_header.length = headerlen;
136 s->crypto_header.offset = ret;
139 * Zero fill all space in cluster so it has predictable
140 * content, as we may not initialize some regions of the
141 * header (eg only 1 out of 8 key slots will be initialized)
143 clusterlen = size_to_clusters(s, headerlen) * s->cluster_size;
144 assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen, false) == 0);
145 ret = bdrv_pwrite_zeroes(bs->file,
146 ret,
147 clusterlen, 0);
148 if (ret < 0) {
149 error_setg_errno(errp, -ret, "Could not zero fill encryption header");
150 return -1;
153 return ret;
157 static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset,
158 const uint8_t *buf, size_t buflen,
159 void *opaque, Error **errp)
161 BlockDriverState *bs = opaque;
162 BDRVQcow2State *s = bs->opaque;
163 ssize_t ret;
165 if ((offset + buflen) > s->crypto_header.length) {
166 error_setg(errp, "Request for data outside of extension header");
167 return -1;
170 ret = bdrv_pwrite(bs->file,
171 s->crypto_header.offset + offset, buf, buflen);
172 if (ret < 0) {
173 error_setg_errno(errp, -ret, "Could not read encryption header");
174 return -1;
176 return ret;
179 static QDict*
180 qcow2_extract_crypto_opts(QemuOpts *opts, const char *fmt, Error **errp)
182 QDict *cryptoopts_qdict;
183 QDict *opts_qdict;
185 /* Extract "encrypt." options into a qdict */
186 opts_qdict = qemu_opts_to_qdict(opts, NULL);
187 qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt.");
188 qobject_unref(opts_qdict);
189 qdict_put_str(cryptoopts_qdict, "format", fmt);
190 return cryptoopts_qdict;
194 * read qcow2 extension and fill bs
195 * start reading from start_offset
196 * finish reading upon magic of value 0 or when end_offset reached
197 * unknown magic is skipped (future extension this version knows nothing about)
198 * return 0 upon success, non-0 otherwise
200 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
201 uint64_t end_offset, void **p_feature_table,
202 int flags, bool *need_update_header,
203 Error **errp)
205 BDRVQcow2State *s = bs->opaque;
206 QCowExtension ext;
207 uint64_t offset;
208 int ret;
209 Qcow2BitmapHeaderExt bitmaps_ext;
211 if (need_update_header != NULL) {
212 *need_update_header = false;
215 #ifdef DEBUG_EXT
216 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
217 #endif
218 offset = start_offset;
219 while (offset < end_offset) {
221 #ifdef DEBUG_EXT
222 /* Sanity check */
223 if (offset > s->cluster_size)
224 printf("qcow2_read_extension: suspicious offset %lu\n", offset);
226 printf("attempting to read extended header in offset %lu\n", offset);
227 #endif
229 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext));
230 if (ret < 0) {
231 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: "
232 "pread fail from offset %" PRIu64, offset);
233 return 1;
235 ext.magic = be32_to_cpu(ext.magic);
236 ext.len = be32_to_cpu(ext.len);
237 offset += sizeof(ext);
238 #ifdef DEBUG_EXT
239 printf("ext.magic = 0x%x\n", ext.magic);
240 #endif
241 if (offset > end_offset || ext.len > end_offset - offset) {
242 error_setg(errp, "Header extension too large");
243 return -EINVAL;
246 switch (ext.magic) {
247 case QCOW2_EXT_MAGIC_END:
248 return 0;
250 case QCOW2_EXT_MAGIC_BACKING_FORMAT:
251 if (ext.len >= sizeof(bs->backing_format)) {
252 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32
253 " too large (>=%zu)", ext.len,
254 sizeof(bs->backing_format));
255 return 2;
257 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len);
258 if (ret < 0) {
259 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: "
260 "Could not read format name");
261 return 3;
263 bs->backing_format[ext.len] = '\0';
264 s->image_backing_format = g_strdup(bs->backing_format);
265 #ifdef DEBUG_EXT
266 printf("Qcow2: Got format extension %s\n", bs->backing_format);
267 #endif
268 break;
270 case QCOW2_EXT_MAGIC_FEATURE_TABLE:
271 if (p_feature_table != NULL) {
272 void *feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature));
273 ret = bdrv_pread(bs->file, offset , feature_table, ext.len);
274 if (ret < 0) {
275 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: "
276 "Could not read table");
277 return ret;
280 *p_feature_table = feature_table;
282 break;
284 case QCOW2_EXT_MAGIC_CRYPTO_HEADER: {
285 unsigned int cflags = 0;
286 if (s->crypt_method_header != QCOW_CRYPT_LUKS) {
287 error_setg(errp, "CRYPTO header extension only "
288 "expected with LUKS encryption method");
289 return -EINVAL;
291 if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) {
292 error_setg(errp, "CRYPTO header extension size %u, "
293 "but expected size %zu", ext.len,
294 sizeof(Qcow2CryptoHeaderExtension));
295 return -EINVAL;
298 ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len);
299 if (ret < 0) {
300 error_setg_errno(errp, -ret,
301 "Unable to read CRYPTO header extension");
302 return ret;
304 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset);
305 s->crypto_header.length = be64_to_cpu(s->crypto_header.length);
307 if ((s->crypto_header.offset % s->cluster_size) != 0) {
308 error_setg(errp, "Encryption header offset '%" PRIu64 "' is "
309 "not a multiple of cluster size '%u'",
310 s->crypto_header.offset, s->cluster_size);
311 return -EINVAL;
314 if (flags & BDRV_O_NO_IO) {
315 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
317 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.",
318 qcow2_crypto_hdr_read_func,
319 bs, cflags, QCOW2_MAX_THREADS, errp);
320 if (!s->crypto) {
321 return -EINVAL;
323 } break;
325 case QCOW2_EXT_MAGIC_BITMAPS:
326 if (ext.len != sizeof(bitmaps_ext)) {
327 error_setg_errno(errp, -ret, "bitmaps_ext: "
328 "Invalid extension length");
329 return -EINVAL;
332 if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) {
333 if (s->qcow_version < 3) {
334 /* Let's be a bit more specific */
335 warn_report("This qcow2 v2 image contains bitmaps, but "
336 "they may have been modified by a program "
337 "without persistent bitmap support; so now "
338 "they must all be considered inconsistent");
339 } else {
340 warn_report("a program lacking bitmap support "
341 "modified this file, so all bitmaps are now "
342 "considered inconsistent");
344 error_printf("Some clusters may be leaked, "
345 "run 'qemu-img check -r' on the image "
346 "file to fix.");
347 if (need_update_header != NULL) {
348 /* Updating is needed to drop invalid bitmap extension. */
349 *need_update_header = true;
351 break;
354 ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len);
355 if (ret < 0) {
356 error_setg_errno(errp, -ret, "bitmaps_ext: "
357 "Could not read ext header");
358 return ret;
361 if (bitmaps_ext.reserved32 != 0) {
362 error_setg_errno(errp, -ret, "bitmaps_ext: "
363 "Reserved field is not zero");
364 return -EINVAL;
367 bitmaps_ext.nb_bitmaps = be32_to_cpu(bitmaps_ext.nb_bitmaps);
368 bitmaps_ext.bitmap_directory_size =
369 be64_to_cpu(bitmaps_ext.bitmap_directory_size);
370 bitmaps_ext.bitmap_directory_offset =
371 be64_to_cpu(bitmaps_ext.bitmap_directory_offset);
373 if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) {
374 error_setg(errp,
375 "bitmaps_ext: Image has %" PRIu32 " bitmaps, "
376 "exceeding the QEMU supported maximum of %d",
377 bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS);
378 return -EINVAL;
381 if (bitmaps_ext.nb_bitmaps == 0) {
382 error_setg(errp, "found bitmaps extension with zero bitmaps");
383 return -EINVAL;
386 if (offset_into_cluster(s, bitmaps_ext.bitmap_directory_offset)) {
387 error_setg(errp, "bitmaps_ext: "
388 "invalid bitmap directory offset");
389 return -EINVAL;
392 if (bitmaps_ext.bitmap_directory_size >
393 QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
394 error_setg(errp, "bitmaps_ext: "
395 "bitmap directory size (%" PRIu64 ") exceeds "
396 "the maximum supported size (%d)",
397 bitmaps_ext.bitmap_directory_size,
398 QCOW2_MAX_BITMAP_DIRECTORY_SIZE);
399 return -EINVAL;
402 s->nb_bitmaps = bitmaps_ext.nb_bitmaps;
403 s->bitmap_directory_offset =
404 bitmaps_ext.bitmap_directory_offset;
405 s->bitmap_directory_size =
406 bitmaps_ext.bitmap_directory_size;
408 #ifdef DEBUG_EXT
409 printf("Qcow2: Got bitmaps extension: "
410 "offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n",
411 s->bitmap_directory_offset, s->nb_bitmaps);
412 #endif
413 break;
415 case QCOW2_EXT_MAGIC_DATA_FILE:
417 s->image_data_file = g_malloc0(ext.len + 1);
418 ret = bdrv_pread(bs->file, offset, s->image_data_file, ext.len);
419 if (ret < 0) {
420 error_setg_errno(errp, -ret,
421 "ERROR: Could not read data file name");
422 return ret;
424 #ifdef DEBUG_EXT
425 printf("Qcow2: Got external data file %s\n", s->image_data_file);
426 #endif
427 break;
430 default:
431 /* unknown magic - save it in case we need to rewrite the header */
432 /* If you add a new feature, make sure to also update the fast
433 * path of qcow2_make_empty() to deal with it. */
435 Qcow2UnknownHeaderExtension *uext;
437 uext = g_malloc0(sizeof(*uext) + ext.len);
438 uext->magic = ext.magic;
439 uext->len = ext.len;
440 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next);
442 ret = bdrv_pread(bs->file, offset , uext->data, uext->len);
443 if (ret < 0) {
444 error_setg_errno(errp, -ret, "ERROR: unknown extension: "
445 "Could not read data");
446 return ret;
449 break;
452 offset += ((ext.len + 7) & ~7);
455 return 0;
458 static void cleanup_unknown_header_ext(BlockDriverState *bs)
460 BDRVQcow2State *s = bs->opaque;
461 Qcow2UnknownHeaderExtension *uext, *next;
463 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) {
464 QLIST_REMOVE(uext, next);
465 g_free(uext);
469 static void report_unsupported_feature(Error **errp, Qcow2Feature *table,
470 uint64_t mask)
472 g_autoptr(GString) features = g_string_sized_new(60);
474 while (table && table->name[0] != '\0') {
475 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) {
476 if (mask & (1ULL << table->bit)) {
477 if (features->len > 0) {
478 g_string_append(features, ", ");
480 g_string_append_printf(features, "%.46s", table->name);
481 mask &= ~(1ULL << table->bit);
484 table++;
487 if (mask) {
488 if (features->len > 0) {
489 g_string_append(features, ", ");
491 g_string_append_printf(features,
492 "Unknown incompatible feature: %" PRIx64, mask);
495 error_setg(errp, "Unsupported qcow2 feature(s): %s", features->str);
499 * Sets the dirty bit and flushes afterwards if necessary.
501 * The incompatible_features bit is only set if the image file header was
502 * updated successfully. Therefore it is not required to check the return
503 * value of this function.
505 int qcow2_mark_dirty(BlockDriverState *bs)
507 BDRVQcow2State *s = bs->opaque;
508 uint64_t val;
509 int ret;
511 assert(s->qcow_version >= 3);
513 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
514 return 0; /* already dirty */
517 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY);
518 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features),
519 &val, sizeof(val));
520 if (ret < 0) {
521 return ret;
523 ret = bdrv_flush(bs->file->bs);
524 if (ret < 0) {
525 return ret;
528 /* Only treat image as dirty if the header was updated successfully */
529 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY;
530 return 0;
534 * Clears the dirty bit and flushes before if necessary. Only call this
535 * function when there are no pending requests, it does not guard against
536 * concurrent requests dirtying the image.
538 static int qcow2_mark_clean(BlockDriverState *bs)
540 BDRVQcow2State *s = bs->opaque;
542 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
543 int ret;
545 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY;
547 ret = qcow2_flush_caches(bs);
548 if (ret < 0) {
549 return ret;
552 return qcow2_update_header(bs);
554 return 0;
558 * Marks the image as corrupt.
560 int qcow2_mark_corrupt(BlockDriverState *bs)
562 BDRVQcow2State *s = bs->opaque;
564 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT;
565 return qcow2_update_header(bs);
569 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
570 * before if necessary.
572 int qcow2_mark_consistent(BlockDriverState *bs)
574 BDRVQcow2State *s = bs->opaque;
576 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
577 int ret = qcow2_flush_caches(bs);
578 if (ret < 0) {
579 return ret;
582 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT;
583 return qcow2_update_header(bs);
585 return 0;
588 static void qcow2_add_check_result(BdrvCheckResult *out,
589 const BdrvCheckResult *src,
590 bool set_allocation_info)
592 out->corruptions += src->corruptions;
593 out->leaks += src->leaks;
594 out->check_errors += src->check_errors;
595 out->corruptions_fixed += src->corruptions_fixed;
596 out->leaks_fixed += src->leaks_fixed;
598 if (set_allocation_info) {
599 out->image_end_offset = src->image_end_offset;
600 out->bfi = src->bfi;
604 static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs,
605 BdrvCheckResult *result,
606 BdrvCheckMode fix)
608 BdrvCheckResult snapshot_res = {};
609 BdrvCheckResult refcount_res = {};
610 int ret;
612 memset(result, 0, sizeof(*result));
614 ret = qcow2_check_read_snapshot_table(bs, &snapshot_res, fix);
615 if (ret < 0) {
616 qcow2_add_check_result(result, &snapshot_res, false);
617 return ret;
620 ret = qcow2_check_refcounts(bs, &refcount_res, fix);
621 qcow2_add_check_result(result, &refcount_res, true);
622 if (ret < 0) {
623 qcow2_add_check_result(result, &snapshot_res, false);
624 return ret;
627 ret = qcow2_check_fix_snapshot_table(bs, &snapshot_res, fix);
628 qcow2_add_check_result(result, &snapshot_res, false);
629 if (ret < 0) {
630 return ret;
633 if (fix && result->check_errors == 0 && result->corruptions == 0) {
634 ret = qcow2_mark_clean(bs);
635 if (ret < 0) {
636 return ret;
638 return qcow2_mark_consistent(bs);
640 return ret;
643 static int coroutine_fn qcow2_co_check(BlockDriverState *bs,
644 BdrvCheckResult *result,
645 BdrvCheckMode fix)
647 BDRVQcow2State *s = bs->opaque;
648 int ret;
650 qemu_co_mutex_lock(&s->lock);
651 ret = qcow2_co_check_locked(bs, result, fix);
652 qemu_co_mutex_unlock(&s->lock);
653 return ret;
656 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset,
657 uint64_t entries, size_t entry_len,
658 int64_t max_size_bytes, const char *table_name,
659 Error **errp)
661 BDRVQcow2State *s = bs->opaque;
663 if (entries > max_size_bytes / entry_len) {
664 error_setg(errp, "%s too large", table_name);
665 return -EFBIG;
668 /* Use signed INT64_MAX as the maximum even for uint64_t header fields,
669 * because values will be passed to qemu functions taking int64_t. */
670 if ((INT64_MAX - entries * entry_len < offset) ||
671 (offset_into_cluster(s, offset) != 0)) {
672 error_setg(errp, "%s offset invalid", table_name);
673 return -EINVAL;
676 return 0;
679 static const char *const mutable_opts[] = {
680 QCOW2_OPT_LAZY_REFCOUNTS,
681 QCOW2_OPT_DISCARD_REQUEST,
682 QCOW2_OPT_DISCARD_SNAPSHOT,
683 QCOW2_OPT_DISCARD_OTHER,
684 QCOW2_OPT_OVERLAP,
685 QCOW2_OPT_OVERLAP_TEMPLATE,
686 QCOW2_OPT_OVERLAP_MAIN_HEADER,
687 QCOW2_OPT_OVERLAP_ACTIVE_L1,
688 QCOW2_OPT_OVERLAP_ACTIVE_L2,
689 QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
690 QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
691 QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
692 QCOW2_OPT_OVERLAP_INACTIVE_L1,
693 QCOW2_OPT_OVERLAP_INACTIVE_L2,
694 QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY,
695 QCOW2_OPT_CACHE_SIZE,
696 QCOW2_OPT_L2_CACHE_SIZE,
697 QCOW2_OPT_L2_CACHE_ENTRY_SIZE,
698 QCOW2_OPT_REFCOUNT_CACHE_SIZE,
699 QCOW2_OPT_CACHE_CLEAN_INTERVAL,
700 NULL
703 static QemuOptsList qcow2_runtime_opts = {
704 .name = "qcow2",
705 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head),
706 .desc = {
708 .name = QCOW2_OPT_LAZY_REFCOUNTS,
709 .type = QEMU_OPT_BOOL,
710 .help = "Postpone refcount updates",
713 .name = QCOW2_OPT_DISCARD_REQUEST,
714 .type = QEMU_OPT_BOOL,
715 .help = "Pass guest discard requests to the layer below",
718 .name = QCOW2_OPT_DISCARD_SNAPSHOT,
719 .type = QEMU_OPT_BOOL,
720 .help = "Generate discard requests when snapshot related space "
721 "is freed",
724 .name = QCOW2_OPT_DISCARD_OTHER,
725 .type = QEMU_OPT_BOOL,
726 .help = "Generate discard requests when other clusters are freed",
729 .name = QCOW2_OPT_OVERLAP,
730 .type = QEMU_OPT_STRING,
731 .help = "Selects which overlap checks to perform from a range of "
732 "templates (none, constant, cached, all)",
735 .name = QCOW2_OPT_OVERLAP_TEMPLATE,
736 .type = QEMU_OPT_STRING,
737 .help = "Selects which overlap checks to perform from a range of "
738 "templates (none, constant, cached, all)",
741 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER,
742 .type = QEMU_OPT_BOOL,
743 .help = "Check for unintended writes into the main qcow2 header",
746 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1,
747 .type = QEMU_OPT_BOOL,
748 .help = "Check for unintended writes into the active L1 table",
751 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2,
752 .type = QEMU_OPT_BOOL,
753 .help = "Check for unintended writes into an active L2 table",
756 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
757 .type = QEMU_OPT_BOOL,
758 .help = "Check for unintended writes into the refcount table",
761 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
762 .type = QEMU_OPT_BOOL,
763 .help = "Check for unintended writes into a refcount block",
766 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
767 .type = QEMU_OPT_BOOL,
768 .help = "Check for unintended writes into the snapshot table",
771 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1,
772 .type = QEMU_OPT_BOOL,
773 .help = "Check for unintended writes into an inactive L1 table",
776 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2,
777 .type = QEMU_OPT_BOOL,
778 .help = "Check for unintended writes into an inactive L2 table",
781 .name = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY,
782 .type = QEMU_OPT_BOOL,
783 .help = "Check for unintended writes into the bitmap directory",
786 .name = QCOW2_OPT_CACHE_SIZE,
787 .type = QEMU_OPT_SIZE,
788 .help = "Maximum combined metadata (L2 tables and refcount blocks) "
789 "cache size",
792 .name = QCOW2_OPT_L2_CACHE_SIZE,
793 .type = QEMU_OPT_SIZE,
794 .help = "Maximum L2 table cache size",
797 .name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE,
798 .type = QEMU_OPT_SIZE,
799 .help = "Size of each entry in the L2 cache",
802 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE,
803 .type = QEMU_OPT_SIZE,
804 .help = "Maximum refcount block cache size",
807 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL,
808 .type = QEMU_OPT_NUMBER,
809 .help = "Clean unused cache entries after this time (in seconds)",
811 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.",
812 "ID of secret providing qcow2 AES key or LUKS passphrase"),
813 { /* end of list */ }
817 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = {
818 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER,
819 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1,
820 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2,
821 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
822 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
823 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
824 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1,
825 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2,
826 [QCOW2_OL_BITMAP_DIRECTORY_BITNR] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY,
829 static void cache_clean_timer_cb(void *opaque)
831 BlockDriverState *bs = opaque;
832 BDRVQcow2State *s = bs->opaque;
833 qcow2_cache_clean_unused(s->l2_table_cache);
834 qcow2_cache_clean_unused(s->refcount_block_cache);
835 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
836 (int64_t) s->cache_clean_interval * 1000);
839 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context)
841 BDRVQcow2State *s = bs->opaque;
842 if (s->cache_clean_interval > 0) {
843 s->cache_clean_timer =
844 aio_timer_new_with_attrs(context, QEMU_CLOCK_VIRTUAL,
845 SCALE_MS, QEMU_TIMER_ATTR_EXTERNAL,
846 cache_clean_timer_cb, bs);
847 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
848 (int64_t) s->cache_clean_interval * 1000);
852 static void cache_clean_timer_del(BlockDriverState *bs)
854 BDRVQcow2State *s = bs->opaque;
855 if (s->cache_clean_timer) {
856 timer_free(s->cache_clean_timer);
857 s->cache_clean_timer = NULL;
861 static void qcow2_detach_aio_context(BlockDriverState *bs)
863 cache_clean_timer_del(bs);
866 static void qcow2_attach_aio_context(BlockDriverState *bs,
867 AioContext *new_context)
869 cache_clean_timer_init(bs, new_context);
872 static bool read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
873 uint64_t *l2_cache_size,
874 uint64_t *l2_cache_entry_size,
875 uint64_t *refcount_cache_size, Error **errp)
877 BDRVQcow2State *s = bs->opaque;
878 uint64_t combined_cache_size, l2_cache_max_setting;
879 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set;
880 bool l2_cache_entry_size_set;
881 int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size;
882 uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
883 uint64_t max_l2_entries = DIV_ROUND_UP(virtual_disk_size, s->cluster_size);
884 /* An L2 table is always one cluster in size so the max cache size
885 * should be a multiple of the cluster size. */
886 uint64_t max_l2_cache = ROUND_UP(max_l2_entries * l2_entry_size(s),
887 s->cluster_size);
889 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE);
890 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE);
891 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
892 l2_cache_entry_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE);
894 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0);
895 l2_cache_max_setting = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE,
896 DEFAULT_L2_CACHE_MAX_SIZE);
897 *refcount_cache_size = qemu_opt_get_size(opts,
898 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0);
900 *l2_cache_entry_size = qemu_opt_get_size(
901 opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size);
903 *l2_cache_size = MIN(max_l2_cache, l2_cache_max_setting);
905 if (combined_cache_size_set) {
906 if (l2_cache_size_set && refcount_cache_size_set) {
907 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE
908 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set "
909 "at the same time");
910 return false;
911 } else if (l2_cache_size_set &&
912 (l2_cache_max_setting > combined_cache_size)) {
913 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed "
914 QCOW2_OPT_CACHE_SIZE);
915 return false;
916 } else if (*refcount_cache_size > combined_cache_size) {
917 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed "
918 QCOW2_OPT_CACHE_SIZE);
919 return false;
922 if (l2_cache_size_set) {
923 *refcount_cache_size = combined_cache_size - *l2_cache_size;
924 } else if (refcount_cache_size_set) {
925 *l2_cache_size = combined_cache_size - *refcount_cache_size;
926 } else {
927 /* Assign as much memory as possible to the L2 cache, and
928 * use the remainder for the refcount cache */
929 if (combined_cache_size >= max_l2_cache + min_refcount_cache) {
930 *l2_cache_size = max_l2_cache;
931 *refcount_cache_size = combined_cache_size - *l2_cache_size;
932 } else {
933 *refcount_cache_size =
934 MIN(combined_cache_size, min_refcount_cache);
935 *l2_cache_size = combined_cache_size - *refcount_cache_size;
941 * If the L2 cache is not enough to cover the whole disk then
942 * default to 4KB entries. Smaller entries reduce the cost of
943 * loads and evictions and increase I/O performance.
945 if (*l2_cache_size < max_l2_cache && !l2_cache_entry_size_set) {
946 *l2_cache_entry_size = MIN(s->cluster_size, 4096);
949 /* l2_cache_size and refcount_cache_size are ensured to have at least
950 * their minimum values in qcow2_update_options_prepare() */
952 if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) ||
953 *l2_cache_entry_size > s->cluster_size ||
954 !is_power_of_2(*l2_cache_entry_size)) {
955 error_setg(errp, "L2 cache entry size must be a power of two "
956 "between %d and the cluster size (%d)",
957 1 << MIN_CLUSTER_BITS, s->cluster_size);
958 return false;
961 return true;
964 typedef struct Qcow2ReopenState {
965 Qcow2Cache *l2_table_cache;
966 Qcow2Cache *refcount_block_cache;
967 int l2_slice_size; /* Number of entries in a slice of the L2 table */
968 bool use_lazy_refcounts;
969 int overlap_check;
970 bool discard_passthrough[QCOW2_DISCARD_MAX];
971 uint64_t cache_clean_interval;
972 QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */
973 } Qcow2ReopenState;
975 static int qcow2_update_options_prepare(BlockDriverState *bs,
976 Qcow2ReopenState *r,
977 QDict *options, int flags,
978 Error **errp)
980 BDRVQcow2State *s = bs->opaque;
981 QemuOpts *opts = NULL;
982 const char *opt_overlap_check, *opt_overlap_check_template;
983 int overlap_check_template = 0;
984 uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size;
985 int i;
986 const char *encryptfmt;
987 QDict *encryptopts = NULL;
988 int ret;
990 qdict_extract_subqdict(options, &encryptopts, "encrypt.");
991 encryptfmt = qdict_get_try_str(encryptopts, "format");
993 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort);
994 if (!qemu_opts_absorb_qdict(opts, options, errp)) {
995 ret = -EINVAL;
996 goto fail;
999 /* get L2 table/refcount block cache size from command line options */
1000 if (!read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size,
1001 &refcount_cache_size, errp)) {
1002 ret = -EINVAL;
1003 goto fail;
1006 l2_cache_size /= l2_cache_entry_size;
1007 if (l2_cache_size < MIN_L2_CACHE_SIZE) {
1008 l2_cache_size = MIN_L2_CACHE_SIZE;
1010 if (l2_cache_size > INT_MAX) {
1011 error_setg(errp, "L2 cache size too big");
1012 ret = -EINVAL;
1013 goto fail;
1016 refcount_cache_size /= s->cluster_size;
1017 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) {
1018 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE;
1020 if (refcount_cache_size > INT_MAX) {
1021 error_setg(errp, "Refcount cache size too big");
1022 ret = -EINVAL;
1023 goto fail;
1026 /* alloc new L2 table/refcount block cache, flush old one */
1027 if (s->l2_table_cache) {
1028 ret = qcow2_cache_flush(bs, s->l2_table_cache);
1029 if (ret) {
1030 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache");
1031 goto fail;
1035 if (s->refcount_block_cache) {
1036 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
1037 if (ret) {
1038 error_setg_errno(errp, -ret,
1039 "Failed to flush the refcount block cache");
1040 goto fail;
1044 r->l2_slice_size = l2_cache_entry_size / l2_entry_size(s);
1045 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size,
1046 l2_cache_entry_size);
1047 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size,
1048 s->cluster_size);
1049 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) {
1050 error_setg(errp, "Could not allocate metadata caches");
1051 ret = -ENOMEM;
1052 goto fail;
1055 /* New interval for cache cleanup timer */
1056 r->cache_clean_interval =
1057 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL,
1058 DEFAULT_CACHE_CLEAN_INTERVAL);
1059 #ifndef CONFIG_LINUX
1060 if (r->cache_clean_interval != 0) {
1061 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL
1062 " not supported on this host");
1063 ret = -EINVAL;
1064 goto fail;
1066 #endif
1067 if (r->cache_clean_interval > UINT_MAX) {
1068 error_setg(errp, "Cache clean interval too big");
1069 ret = -EINVAL;
1070 goto fail;
1073 /* lazy-refcounts; flush if going from enabled to disabled */
1074 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
1075 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
1076 if (r->use_lazy_refcounts && s->qcow_version < 3) {
1077 error_setg(errp, "Lazy refcounts require a qcow2 image with at least "
1078 "qemu 1.1 compatibility level");
1079 ret = -EINVAL;
1080 goto fail;
1083 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) {
1084 ret = qcow2_mark_clean(bs);
1085 if (ret < 0) {
1086 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts");
1087 goto fail;
1091 /* Overlap check options */
1092 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP);
1093 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE);
1094 if (opt_overlap_check_template && opt_overlap_check &&
1095 strcmp(opt_overlap_check_template, opt_overlap_check))
1097 error_setg(errp, "Conflicting values for qcow2 options '"
1098 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
1099 "' ('%s')", opt_overlap_check, opt_overlap_check_template);
1100 ret = -EINVAL;
1101 goto fail;
1103 if (!opt_overlap_check) {
1104 opt_overlap_check = opt_overlap_check_template ?: "cached";
1107 if (!strcmp(opt_overlap_check, "none")) {
1108 overlap_check_template = 0;
1109 } else if (!strcmp(opt_overlap_check, "constant")) {
1110 overlap_check_template = QCOW2_OL_CONSTANT;
1111 } else if (!strcmp(opt_overlap_check, "cached")) {
1112 overlap_check_template = QCOW2_OL_CACHED;
1113 } else if (!strcmp(opt_overlap_check, "all")) {
1114 overlap_check_template = QCOW2_OL_ALL;
1115 } else {
1116 error_setg(errp, "Unsupported value '%s' for qcow2 option "
1117 "'overlap-check'. Allowed are any of the following: "
1118 "none, constant, cached, all", opt_overlap_check);
1119 ret = -EINVAL;
1120 goto fail;
1123 r->overlap_check = 0;
1124 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) {
1125 /* overlap-check defines a template bitmask, but every flag may be
1126 * overwritten through the associated boolean option */
1127 r->overlap_check |=
1128 qemu_opt_get_bool(opts, overlap_bool_option_names[i],
1129 overlap_check_template & (1 << i)) << i;
1132 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
1133 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
1134 r->discard_passthrough[QCOW2_DISCARD_REQUEST] =
1135 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST,
1136 flags & BDRV_O_UNMAP);
1137 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
1138 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true);
1139 r->discard_passthrough[QCOW2_DISCARD_OTHER] =
1140 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false);
1142 switch (s->crypt_method_header) {
1143 case QCOW_CRYPT_NONE:
1144 if (encryptfmt) {
1145 error_setg(errp, "No encryption in image header, but options "
1146 "specified format '%s'", encryptfmt);
1147 ret = -EINVAL;
1148 goto fail;
1150 break;
1152 case QCOW_CRYPT_AES:
1153 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
1154 error_setg(errp,
1155 "Header reported 'aes' encryption format but "
1156 "options specify '%s'", encryptfmt);
1157 ret = -EINVAL;
1158 goto fail;
1160 qdict_put_str(encryptopts, "format", "qcow");
1161 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
1162 if (!r->crypto_opts) {
1163 ret = -EINVAL;
1164 goto fail;
1166 break;
1168 case QCOW_CRYPT_LUKS:
1169 if (encryptfmt && !g_str_equal(encryptfmt, "luks")) {
1170 error_setg(errp,
1171 "Header reported 'luks' encryption format but "
1172 "options specify '%s'", encryptfmt);
1173 ret = -EINVAL;
1174 goto fail;
1176 qdict_put_str(encryptopts, "format", "luks");
1177 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
1178 if (!r->crypto_opts) {
1179 ret = -EINVAL;
1180 goto fail;
1182 break;
1184 default:
1185 error_setg(errp, "Unsupported encryption method %d",
1186 s->crypt_method_header);
1187 ret = -EINVAL;
1188 goto fail;
1191 ret = 0;
1192 fail:
1193 qobject_unref(encryptopts);
1194 qemu_opts_del(opts);
1195 opts = NULL;
1196 return ret;
1199 static void qcow2_update_options_commit(BlockDriverState *bs,
1200 Qcow2ReopenState *r)
1202 BDRVQcow2State *s = bs->opaque;
1203 int i;
1205 if (s->l2_table_cache) {
1206 qcow2_cache_destroy(s->l2_table_cache);
1208 if (s->refcount_block_cache) {
1209 qcow2_cache_destroy(s->refcount_block_cache);
1211 s->l2_table_cache = r->l2_table_cache;
1212 s->refcount_block_cache = r->refcount_block_cache;
1213 s->l2_slice_size = r->l2_slice_size;
1215 s->overlap_check = r->overlap_check;
1216 s->use_lazy_refcounts = r->use_lazy_refcounts;
1218 for (i = 0; i < QCOW2_DISCARD_MAX; i++) {
1219 s->discard_passthrough[i] = r->discard_passthrough[i];
1222 if (s->cache_clean_interval != r->cache_clean_interval) {
1223 cache_clean_timer_del(bs);
1224 s->cache_clean_interval = r->cache_clean_interval;
1225 cache_clean_timer_init(bs, bdrv_get_aio_context(bs));
1228 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts);
1229 s->crypto_opts = r->crypto_opts;
1232 static void qcow2_update_options_abort(BlockDriverState *bs,
1233 Qcow2ReopenState *r)
1235 if (r->l2_table_cache) {
1236 qcow2_cache_destroy(r->l2_table_cache);
1238 if (r->refcount_block_cache) {
1239 qcow2_cache_destroy(r->refcount_block_cache);
1241 qapi_free_QCryptoBlockOpenOptions(r->crypto_opts);
1244 static int qcow2_update_options(BlockDriverState *bs, QDict *options,
1245 int flags, Error **errp)
1247 Qcow2ReopenState r = {};
1248 int ret;
1250 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp);
1251 if (ret >= 0) {
1252 qcow2_update_options_commit(bs, &r);
1253 } else {
1254 qcow2_update_options_abort(bs, &r);
1257 return ret;
1260 static int validate_compression_type(BDRVQcow2State *s, Error **errp)
1262 switch (s->compression_type) {
1263 case QCOW2_COMPRESSION_TYPE_ZLIB:
1264 #ifdef CONFIG_ZSTD
1265 case QCOW2_COMPRESSION_TYPE_ZSTD:
1266 #endif
1267 break;
1269 default:
1270 error_setg(errp, "qcow2: unknown compression type: %u",
1271 s->compression_type);
1272 return -ENOTSUP;
1276 * if the compression type differs from QCOW2_COMPRESSION_TYPE_ZLIB
1277 * the incompatible feature flag must be set
1279 if (s->compression_type == QCOW2_COMPRESSION_TYPE_ZLIB) {
1280 if (s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION) {
1281 error_setg(errp, "qcow2: Compression type incompatible feature "
1282 "bit must not be set");
1283 return -EINVAL;
1285 } else {
1286 if (!(s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION)) {
1287 error_setg(errp, "qcow2: Compression type incompatible feature "
1288 "bit must be set");
1289 return -EINVAL;
1293 return 0;
1296 /* Called with s->lock held. */
1297 static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
1298 int flags, Error **errp)
1300 ERRP_GUARD();
1301 BDRVQcow2State *s = bs->opaque;
1302 unsigned int len, i;
1303 int ret = 0;
1304 QCowHeader header;
1305 uint64_t ext_end;
1306 uint64_t l1_vm_state_index;
1307 bool update_header = false;
1309 ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
1310 if (ret < 0) {
1311 error_setg_errno(errp, -ret, "Could not read qcow2 header");
1312 goto fail;
1314 header.magic = be32_to_cpu(header.magic);
1315 header.version = be32_to_cpu(header.version);
1316 header.backing_file_offset = be64_to_cpu(header.backing_file_offset);
1317 header.backing_file_size = be32_to_cpu(header.backing_file_size);
1318 header.size = be64_to_cpu(header.size);
1319 header.cluster_bits = be32_to_cpu(header.cluster_bits);
1320 header.crypt_method = be32_to_cpu(header.crypt_method);
1321 header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
1322 header.l1_size = be32_to_cpu(header.l1_size);
1323 header.refcount_table_offset = be64_to_cpu(header.refcount_table_offset);
1324 header.refcount_table_clusters =
1325 be32_to_cpu(header.refcount_table_clusters);
1326 header.snapshots_offset = be64_to_cpu(header.snapshots_offset);
1327 header.nb_snapshots = be32_to_cpu(header.nb_snapshots);
1329 if (header.magic != QCOW_MAGIC) {
1330 error_setg(errp, "Image is not in qcow2 format");
1331 ret = -EINVAL;
1332 goto fail;
1334 if (header.version < 2 || header.version > 3) {
1335 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version);
1336 ret = -ENOTSUP;
1337 goto fail;
1340 s->qcow_version = header.version;
1342 /* Initialise cluster size */
1343 if (header.cluster_bits < MIN_CLUSTER_BITS ||
1344 header.cluster_bits > MAX_CLUSTER_BITS) {
1345 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32,
1346 header.cluster_bits);
1347 ret = -EINVAL;
1348 goto fail;
1351 s->cluster_bits = header.cluster_bits;
1352 s->cluster_size = 1 << s->cluster_bits;
1354 /* Initialise version 3 header fields */
1355 if (header.version == 2) {
1356 header.incompatible_features = 0;
1357 header.compatible_features = 0;
1358 header.autoclear_features = 0;
1359 header.refcount_order = 4;
1360 header.header_length = 72;
1361 } else {
1362 header.incompatible_features =
1363 be64_to_cpu(header.incompatible_features);
1364 header.compatible_features = be64_to_cpu(header.compatible_features);
1365 header.autoclear_features = be64_to_cpu(header.autoclear_features);
1366 header.refcount_order = be32_to_cpu(header.refcount_order);
1367 header.header_length = be32_to_cpu(header.header_length);
1369 if (header.header_length < 104) {
1370 error_setg(errp, "qcow2 header too short");
1371 ret = -EINVAL;
1372 goto fail;
1376 if (header.header_length > s->cluster_size) {
1377 error_setg(errp, "qcow2 header exceeds cluster size");
1378 ret = -EINVAL;
1379 goto fail;
1382 if (header.header_length > sizeof(header)) {
1383 s->unknown_header_fields_size = header.header_length - sizeof(header);
1384 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size);
1385 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields,
1386 s->unknown_header_fields_size);
1387 if (ret < 0) {
1388 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header "
1389 "fields");
1390 goto fail;
1394 if (header.backing_file_offset > s->cluster_size) {
1395 error_setg(errp, "Invalid backing file offset");
1396 ret = -EINVAL;
1397 goto fail;
1400 if (header.backing_file_offset) {
1401 ext_end = header.backing_file_offset;
1402 } else {
1403 ext_end = 1 << header.cluster_bits;
1406 /* Handle feature bits */
1407 s->incompatible_features = header.incompatible_features;
1408 s->compatible_features = header.compatible_features;
1409 s->autoclear_features = header.autoclear_features;
1412 * Handle compression type
1413 * Older qcow2 images don't contain the compression type header.
1414 * Distinguish them by the header length and use
1415 * the only valid (default) compression type in that case
1417 if (header.header_length > offsetof(QCowHeader, compression_type)) {
1418 s->compression_type = header.compression_type;
1419 } else {
1420 s->compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
1423 ret = validate_compression_type(s, errp);
1424 if (ret) {
1425 goto fail;
1428 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
1429 void *feature_table = NULL;
1430 qcow2_read_extensions(bs, header.header_length, ext_end,
1431 &feature_table, flags, NULL, NULL);
1432 report_unsupported_feature(errp, feature_table,
1433 s->incompatible_features &
1434 ~QCOW2_INCOMPAT_MASK);
1435 ret = -ENOTSUP;
1436 g_free(feature_table);
1437 goto fail;
1440 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
1441 /* Corrupt images may not be written to unless they are being repaired
1443 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
1444 error_setg(errp, "qcow2: Image is corrupt; cannot be opened "
1445 "read/write");
1446 ret = -EACCES;
1447 goto fail;
1451 s->subclusters_per_cluster =
1452 has_subclusters(s) ? QCOW_EXTL2_SUBCLUSTERS_PER_CLUSTER : 1;
1453 s->subcluster_size = s->cluster_size / s->subclusters_per_cluster;
1454 s->subcluster_bits = ctz32(s->subcluster_size);
1456 if (s->subcluster_size < (1 << MIN_CLUSTER_BITS)) {
1457 error_setg(errp, "Unsupported subcluster size: %d", s->subcluster_size);
1458 ret = -EINVAL;
1459 goto fail;
1462 /* Check support for various header values */
1463 if (header.refcount_order > 6) {
1464 error_setg(errp, "Reference count entry width too large; may not "
1465 "exceed 64 bits");
1466 ret = -EINVAL;
1467 goto fail;
1469 s->refcount_order = header.refcount_order;
1470 s->refcount_bits = 1 << s->refcount_order;
1471 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1);
1472 s->refcount_max += s->refcount_max - 1;
1474 s->crypt_method_header = header.crypt_method;
1475 if (s->crypt_method_header) {
1476 if (bdrv_uses_whitelist() &&
1477 s->crypt_method_header == QCOW_CRYPT_AES) {
1478 error_setg(errp,
1479 "Use of AES-CBC encrypted qcow2 images is no longer "
1480 "supported in system emulators");
1481 error_append_hint(errp,
1482 "You can use 'qemu-img convert' to convert your "
1483 "image to an alternative supported format, such "
1484 "as unencrypted qcow2, or raw with the LUKS "
1485 "format instead.\n");
1486 ret = -ENOSYS;
1487 goto fail;
1490 if (s->crypt_method_header == QCOW_CRYPT_AES) {
1491 s->crypt_physical_offset = false;
1492 } else {
1493 /* Assuming LUKS and any future crypt methods we
1494 * add will all use physical offsets, due to the
1495 * fact that the alternative is insecure... */
1496 s->crypt_physical_offset = true;
1499 bs->encrypted = true;
1502 s->l2_bits = s->cluster_bits - ctz32(l2_entry_size(s));
1503 s->l2_size = 1 << s->l2_bits;
1504 /* 2^(s->refcount_order - 3) is the refcount width in bytes */
1505 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3);
1506 s->refcount_block_size = 1 << s->refcount_block_bits;
1507 bs->total_sectors = header.size / BDRV_SECTOR_SIZE;
1508 s->csize_shift = (62 - (s->cluster_bits - 8));
1509 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
1510 s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
1512 s->refcount_table_offset = header.refcount_table_offset;
1513 s->refcount_table_size =
1514 header.refcount_table_clusters << (s->cluster_bits - 3);
1516 if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) {
1517 error_setg(errp, "Image does not contain a reference count table");
1518 ret = -EINVAL;
1519 goto fail;
1522 ret = qcow2_validate_table(bs, s->refcount_table_offset,
1523 header.refcount_table_clusters,
1524 s->cluster_size, QCOW_MAX_REFTABLE_SIZE,
1525 "Reference count table", errp);
1526 if (ret < 0) {
1527 goto fail;
1530 if (!(flags & BDRV_O_CHECK)) {
1532 * The total size in bytes of the snapshot table is checked in
1533 * qcow2_read_snapshots() because the size of each snapshot is
1534 * variable and we don't know it yet.
1535 * Here we only check the offset and number of snapshots.
1537 ret = qcow2_validate_table(bs, header.snapshots_offset,
1538 header.nb_snapshots,
1539 sizeof(QCowSnapshotHeader),
1540 sizeof(QCowSnapshotHeader) *
1541 QCOW_MAX_SNAPSHOTS,
1542 "Snapshot table", errp);
1543 if (ret < 0) {
1544 goto fail;
1548 /* read the level 1 table */
1549 ret = qcow2_validate_table(bs, header.l1_table_offset,
1550 header.l1_size, L1E_SIZE,
1551 QCOW_MAX_L1_SIZE, "Active L1 table", errp);
1552 if (ret < 0) {
1553 goto fail;
1555 s->l1_size = header.l1_size;
1556 s->l1_table_offset = header.l1_table_offset;
1558 l1_vm_state_index = size_to_l1(s, header.size);
1559 if (l1_vm_state_index > INT_MAX) {
1560 error_setg(errp, "Image is too big");
1561 ret = -EFBIG;
1562 goto fail;
1564 s->l1_vm_state_index = l1_vm_state_index;
1566 /* the L1 table must contain at least enough entries to put
1567 header.size bytes */
1568 if (s->l1_size < s->l1_vm_state_index) {
1569 error_setg(errp, "L1 table is too small");
1570 ret = -EINVAL;
1571 goto fail;
1574 if (s->l1_size > 0) {
1575 s->l1_table = qemu_try_blockalign(bs->file->bs, s->l1_size * L1E_SIZE);
1576 if (s->l1_table == NULL) {
1577 error_setg(errp, "Could not allocate L1 table");
1578 ret = -ENOMEM;
1579 goto fail;
1581 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
1582 s->l1_size * L1E_SIZE);
1583 if (ret < 0) {
1584 error_setg_errno(errp, -ret, "Could not read L1 table");
1585 goto fail;
1587 for(i = 0;i < s->l1_size; i++) {
1588 s->l1_table[i] = be64_to_cpu(s->l1_table[i]);
1592 /* Parse driver-specific options */
1593 ret = qcow2_update_options(bs, options, flags, errp);
1594 if (ret < 0) {
1595 goto fail;
1598 s->flags = flags;
1600 ret = qcow2_refcount_init(bs);
1601 if (ret != 0) {
1602 error_setg_errno(errp, -ret, "Could not initialize refcount handling");
1603 goto fail;
1606 QLIST_INIT(&s->cluster_allocs);
1607 QTAILQ_INIT(&s->discards);
1609 /* read qcow2 extensions */
1610 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL,
1611 flags, &update_header, errp)) {
1612 ret = -EINVAL;
1613 goto fail;
1616 /* Open external data file */
1617 s->data_file = bdrv_open_child(NULL, options, "data-file", bs,
1618 &child_of_bds, BDRV_CHILD_DATA,
1619 true, errp);
1620 if (*errp) {
1621 ret = -EINVAL;
1622 goto fail;
1625 if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) {
1626 if (!s->data_file && s->image_data_file) {
1627 s->data_file = bdrv_open_child(s->image_data_file, options,
1628 "data-file", bs, &child_of_bds,
1629 BDRV_CHILD_DATA, false, errp);
1630 if (!s->data_file) {
1631 ret = -EINVAL;
1632 goto fail;
1635 if (!s->data_file) {
1636 error_setg(errp, "'data-file' is required for this image");
1637 ret = -EINVAL;
1638 goto fail;
1641 /* No data here */
1642 bs->file->role &= ~BDRV_CHILD_DATA;
1644 /* Must succeed because we have given up permissions if anything */
1645 bdrv_child_refresh_perms(bs, bs->file, &error_abort);
1646 } else {
1647 if (s->data_file) {
1648 error_setg(errp, "'data-file' can only be set for images with an "
1649 "external data file");
1650 ret = -EINVAL;
1651 goto fail;
1654 s->data_file = bs->file;
1656 if (data_file_is_raw(bs)) {
1657 error_setg(errp, "data-file-raw requires a data file");
1658 ret = -EINVAL;
1659 goto fail;
1663 /* qcow2_read_extension may have set up the crypto context
1664 * if the crypt method needs a header region, some methods
1665 * don't need header extensions, so must check here
1667 if (s->crypt_method_header && !s->crypto) {
1668 if (s->crypt_method_header == QCOW_CRYPT_AES) {
1669 unsigned int cflags = 0;
1670 if (flags & BDRV_O_NO_IO) {
1671 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
1673 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.",
1674 NULL, NULL, cflags,
1675 QCOW2_MAX_THREADS, errp);
1676 if (!s->crypto) {
1677 ret = -EINVAL;
1678 goto fail;
1680 } else if (!(flags & BDRV_O_NO_IO)) {
1681 error_setg(errp, "Missing CRYPTO header for crypt method %d",
1682 s->crypt_method_header);
1683 ret = -EINVAL;
1684 goto fail;
1688 /* read the backing file name */
1689 if (header.backing_file_offset != 0) {
1690 len = header.backing_file_size;
1691 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) ||
1692 len >= sizeof(bs->backing_file)) {
1693 error_setg(errp, "Backing file name too long");
1694 ret = -EINVAL;
1695 goto fail;
1697 ret = bdrv_pread(bs->file, header.backing_file_offset,
1698 bs->auto_backing_file, len);
1699 if (ret < 0) {
1700 error_setg_errno(errp, -ret, "Could not read backing file name");
1701 goto fail;
1703 bs->auto_backing_file[len] = '\0';
1704 pstrcpy(bs->backing_file, sizeof(bs->backing_file),
1705 bs->auto_backing_file);
1706 s->image_backing_file = g_strdup(bs->auto_backing_file);
1710 * Internal snapshots; skip reading them in check mode, because
1711 * we do not need them then, and we do not want to abort because
1712 * of a broken table.
1714 if (!(flags & BDRV_O_CHECK)) {
1715 s->snapshots_offset = header.snapshots_offset;
1716 s->nb_snapshots = header.nb_snapshots;
1718 ret = qcow2_read_snapshots(bs, errp);
1719 if (ret < 0) {
1720 goto fail;
1724 /* Clear unknown autoclear feature bits */
1725 update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK;
1726 update_header = update_header && bdrv_is_writable(bs);
1727 if (update_header) {
1728 s->autoclear_features &= QCOW2_AUTOCLEAR_MASK;
1731 /* == Handle persistent dirty bitmaps ==
1733 * We want load dirty bitmaps in three cases:
1735 * 1. Normal open of the disk in active mode, not related to invalidation
1736 * after migration.
1738 * 2. Invalidation of the target vm after pre-copy phase of migration, if
1739 * bitmaps are _not_ migrating through migration channel, i.e.
1740 * 'dirty-bitmaps' capability is disabled.
1742 * 3. Invalidation of source vm after failed or canceled migration.
1743 * This is a very interesting case. There are two possible types of
1744 * bitmaps:
1746 * A. Stored on inactivation and removed. They should be loaded from the
1747 * image.
1749 * B. Not stored: not-persistent bitmaps and bitmaps, migrated through
1750 * the migration channel (with dirty-bitmaps capability).
1752 * On the other hand, there are two possible sub-cases:
1754 * 3.1 disk was changed by somebody else while were inactive. In this
1755 * case all in-RAM dirty bitmaps (both persistent and not) are
1756 * definitely invalid. And we don't have any method to determine
1757 * this.
1759 * Simple and safe thing is to just drop all the bitmaps of type B on
1760 * inactivation. But in this case we lose bitmaps in valid 4.2 case.
1762 * On the other hand, resuming source vm, if disk was already changed
1763 * is a bad thing anyway: not only bitmaps, the whole vm state is
1764 * out of sync with disk.
1766 * This means, that user or management tool, who for some reason
1767 * decided to resume source vm, after disk was already changed by
1768 * target vm, should at least drop all dirty bitmaps by hand.
1770 * So, we can ignore this case for now, but TODO: "generation"
1771 * extension for qcow2, to determine, that image was changed after
1772 * last inactivation. And if it is changed, we will drop (or at least
1773 * mark as 'invalid' all the bitmaps of type B, both persistent
1774 * and not).
1776 * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved
1777 * to disk ('dirty-bitmaps' capability disabled), or not saved
1778 * ('dirty-bitmaps' capability enabled), but we don't need to care
1779 * of: let's load bitmaps as always: stored bitmaps will be loaded,
1780 * and not stored has flag IN_USE=1 in the image and will be skipped
1781 * on loading.
1783 * One remaining possible case when we don't want load bitmaps:
1785 * 4. Open disk in inactive mode in target vm (bitmaps are migrating or
1786 * will be loaded on invalidation, no needs try loading them before)
1789 if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) {
1790 /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */
1791 bool header_updated;
1792 if (!qcow2_load_dirty_bitmaps(bs, &header_updated, errp)) {
1793 ret = -EINVAL;
1794 goto fail;
1797 update_header = update_header && !header_updated;
1800 if (update_header) {
1801 ret = qcow2_update_header(bs);
1802 if (ret < 0) {
1803 error_setg_errno(errp, -ret, "Could not update qcow2 header");
1804 goto fail;
1808 bs->supported_zero_flags = header.version >= 3 ?
1809 BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK : 0;
1810 bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
1812 /* Repair image if dirty */
1813 if (!(flags & BDRV_O_CHECK) && bdrv_is_writable(bs) &&
1814 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) {
1815 BdrvCheckResult result = {0};
1817 ret = qcow2_co_check_locked(bs, &result,
1818 BDRV_FIX_ERRORS | BDRV_FIX_LEAKS);
1819 if (ret < 0 || result.check_errors) {
1820 if (ret >= 0) {
1821 ret = -EIO;
1823 error_setg_errno(errp, -ret, "Could not repair dirty image");
1824 goto fail;
1828 #ifdef DEBUG_ALLOC
1830 BdrvCheckResult result = {0};
1831 qcow2_check_refcounts(bs, &result, 0);
1833 #endif
1835 qemu_co_queue_init(&s->thread_task_queue);
1837 return ret;
1839 fail:
1840 g_free(s->image_data_file);
1841 if (has_data_file(bs)) {
1842 bdrv_unref_child(bs, s->data_file);
1843 s->data_file = NULL;
1845 g_free(s->unknown_header_fields);
1846 cleanup_unknown_header_ext(bs);
1847 qcow2_free_snapshots(bs);
1848 qcow2_refcount_close(bs);
1849 qemu_vfree(s->l1_table);
1850 /* else pre-write overlap checks in cache_destroy may crash */
1851 s->l1_table = NULL;
1852 cache_clean_timer_del(bs);
1853 if (s->l2_table_cache) {
1854 qcow2_cache_destroy(s->l2_table_cache);
1856 if (s->refcount_block_cache) {
1857 qcow2_cache_destroy(s->refcount_block_cache);
1859 qcrypto_block_free(s->crypto);
1860 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts);
1861 return ret;
1864 typedef struct QCow2OpenCo {
1865 BlockDriverState *bs;
1866 QDict *options;
1867 int flags;
1868 Error **errp;
1869 int ret;
1870 } QCow2OpenCo;
1872 static void coroutine_fn qcow2_open_entry(void *opaque)
1874 QCow2OpenCo *qoc = opaque;
1875 BDRVQcow2State *s = qoc->bs->opaque;
1877 qemu_co_mutex_lock(&s->lock);
1878 qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp);
1879 qemu_co_mutex_unlock(&s->lock);
1882 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
1883 Error **errp)
1885 BDRVQcow2State *s = bs->opaque;
1886 QCow2OpenCo qoc = {
1887 .bs = bs,
1888 .options = options,
1889 .flags = flags,
1890 .errp = errp,
1891 .ret = -EINPROGRESS
1894 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
1895 BDRV_CHILD_IMAGE, false, errp);
1896 if (!bs->file) {
1897 return -EINVAL;
1900 /* Initialise locks */
1901 qemu_co_mutex_init(&s->lock);
1903 if (qemu_in_coroutine()) {
1904 /* From bdrv_co_create. */
1905 qcow2_open_entry(&qoc);
1906 } else {
1907 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
1908 qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc));
1909 BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS);
1911 return qoc.ret;
1914 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp)
1916 BDRVQcow2State *s = bs->opaque;
1918 if (bs->encrypted) {
1919 /* Encryption works on a sector granularity */
1920 bs->bl.request_alignment = qcrypto_block_get_sector_size(s->crypto);
1922 bs->bl.pwrite_zeroes_alignment = s->subcluster_size;
1923 bs->bl.pdiscard_alignment = s->cluster_size;
1926 static int qcow2_reopen_prepare(BDRVReopenState *state,
1927 BlockReopenQueue *queue, Error **errp)
1929 BDRVQcow2State *s = state->bs->opaque;
1930 Qcow2ReopenState *r;
1931 int ret;
1933 r = g_new0(Qcow2ReopenState, 1);
1934 state->opaque = r;
1936 ret = qcow2_update_options_prepare(state->bs, r, state->options,
1937 state->flags, errp);
1938 if (ret < 0) {
1939 goto fail;
1942 /* We need to write out any unwritten data if we reopen read-only. */
1943 if ((state->flags & BDRV_O_RDWR) == 0) {
1944 ret = qcow2_reopen_bitmaps_ro(state->bs, errp);
1945 if (ret < 0) {
1946 goto fail;
1949 ret = bdrv_flush(state->bs);
1950 if (ret < 0) {
1951 goto fail;
1954 ret = qcow2_mark_clean(state->bs);
1955 if (ret < 0) {
1956 goto fail;
1961 * Without an external data file, s->data_file points to the same BdrvChild
1962 * as bs->file. It needs to be resynced after reopen because bs->file may
1963 * be changed. We can't use it in the meantime.
1965 if (!has_data_file(state->bs)) {
1966 assert(s->data_file == state->bs->file);
1967 s->data_file = NULL;
1970 return 0;
1972 fail:
1973 qcow2_update_options_abort(state->bs, r);
1974 g_free(r);
1975 return ret;
1978 static void qcow2_reopen_commit(BDRVReopenState *state)
1980 BDRVQcow2State *s = state->bs->opaque;
1982 qcow2_update_options_commit(state->bs, state->opaque);
1983 if (!s->data_file) {
1985 * If we don't have an external data file, s->data_file was cleared by
1986 * qcow2_reopen_prepare() and needs to be updated.
1988 s->data_file = state->bs->file;
1990 g_free(state->opaque);
1993 static void qcow2_reopen_commit_post(BDRVReopenState *state)
1995 if (state->flags & BDRV_O_RDWR) {
1996 Error *local_err = NULL;
1998 if (qcow2_reopen_bitmaps_rw(state->bs, &local_err) < 0) {
2000 * This is not fatal, bitmaps just left read-only, so all following
2001 * writes will fail. User can remove read-only bitmaps to unblock
2002 * writes or retry reopen.
2004 error_reportf_err(local_err,
2005 "%s: Failed to make dirty bitmaps writable: ",
2006 bdrv_get_node_name(state->bs));
2011 static void qcow2_reopen_abort(BDRVReopenState *state)
2013 BDRVQcow2State *s = state->bs->opaque;
2015 if (!s->data_file) {
2017 * If we don't have an external data file, s->data_file was cleared by
2018 * qcow2_reopen_prepare() and needs to be restored.
2020 s->data_file = state->bs->file;
2022 qcow2_update_options_abort(state->bs, state->opaque);
2023 g_free(state->opaque);
2026 static void qcow2_join_options(QDict *options, QDict *old_options)
2028 bool has_new_overlap_template =
2029 qdict_haskey(options, QCOW2_OPT_OVERLAP) ||
2030 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE);
2031 bool has_new_total_cache_size =
2032 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE);
2033 bool has_all_cache_options;
2035 /* New overlap template overrides all old overlap options */
2036 if (has_new_overlap_template) {
2037 qdict_del(old_options, QCOW2_OPT_OVERLAP);
2038 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE);
2039 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER);
2040 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1);
2041 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2);
2042 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE);
2043 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK);
2044 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE);
2045 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1);
2046 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2);
2049 /* New total cache size overrides all old options */
2050 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) {
2051 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE);
2052 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
2055 qdict_join(options, old_options, false);
2058 * If after merging all cache size options are set, an old total size is
2059 * overwritten. Do keep all options, however, if all three are new. The
2060 * resulting error message is what we want to happen.
2062 has_all_cache_options =
2063 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) ||
2064 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) ||
2065 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
2067 if (has_all_cache_options && !has_new_total_cache_size) {
2068 qdict_del(options, QCOW2_OPT_CACHE_SIZE);
2072 static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs,
2073 bool want_zero,
2074 int64_t offset, int64_t count,
2075 int64_t *pnum, int64_t *map,
2076 BlockDriverState **file)
2078 BDRVQcow2State *s = bs->opaque;
2079 uint64_t host_offset;
2080 unsigned int bytes;
2081 QCow2SubclusterType type;
2082 int ret, status = 0;
2084 qemu_co_mutex_lock(&s->lock);
2086 if (!s->metadata_preallocation_checked) {
2087 ret = qcow2_detect_metadata_preallocation(bs);
2088 s->metadata_preallocation = (ret == 1);
2089 s->metadata_preallocation_checked = true;
2092 bytes = MIN(INT_MAX, count);
2093 ret = qcow2_get_host_offset(bs, offset, &bytes, &host_offset, &type);
2094 qemu_co_mutex_unlock(&s->lock);
2095 if (ret < 0) {
2096 return ret;
2099 *pnum = bytes;
2101 if ((type == QCOW2_SUBCLUSTER_NORMAL ||
2102 type == QCOW2_SUBCLUSTER_ZERO_ALLOC ||
2103 type == QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC) && !s->crypto) {
2104 *map = host_offset;
2105 *file = s->data_file->bs;
2106 status |= BDRV_BLOCK_OFFSET_VALID;
2108 if (type == QCOW2_SUBCLUSTER_ZERO_PLAIN ||
2109 type == QCOW2_SUBCLUSTER_ZERO_ALLOC) {
2110 status |= BDRV_BLOCK_ZERO;
2111 } else if (type != QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN &&
2112 type != QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC) {
2113 status |= BDRV_BLOCK_DATA;
2115 if (s->metadata_preallocation && (status & BDRV_BLOCK_DATA) &&
2116 (status & BDRV_BLOCK_OFFSET_VALID))
2118 status |= BDRV_BLOCK_RECURSE;
2120 return status;
2123 static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs,
2124 QCowL2Meta **pl2meta,
2125 bool link_l2)
2127 int ret = 0;
2128 QCowL2Meta *l2meta = *pl2meta;
2130 while (l2meta != NULL) {
2131 QCowL2Meta *next;
2133 if (link_l2) {
2134 ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
2135 if (ret) {
2136 goto out;
2138 } else {
2139 qcow2_alloc_cluster_abort(bs, l2meta);
2142 /* Take the request off the list of running requests */
2143 QLIST_REMOVE(l2meta, next_in_flight);
2145 qemu_co_queue_restart_all(&l2meta->dependent_requests);
2147 next = l2meta->next;
2148 g_free(l2meta);
2149 l2meta = next;
2151 out:
2152 *pl2meta = l2meta;
2153 return ret;
2156 static coroutine_fn int
2157 qcow2_co_preadv_encrypted(BlockDriverState *bs,
2158 uint64_t host_offset,
2159 uint64_t offset,
2160 uint64_t bytes,
2161 QEMUIOVector *qiov,
2162 uint64_t qiov_offset)
2164 int ret;
2165 BDRVQcow2State *s = bs->opaque;
2166 uint8_t *buf;
2168 assert(bs->encrypted && s->crypto);
2169 assert(bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
2172 * For encrypted images, read everything into a temporary
2173 * contiguous buffer on which the AES functions can work.
2174 * Also, decryption in a separate buffer is better as it
2175 * prevents the guest from learning information about the
2176 * encrypted nature of the virtual disk.
2179 buf = qemu_try_blockalign(s->data_file->bs, bytes);
2180 if (buf == NULL) {
2181 return -ENOMEM;
2184 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
2185 ret = bdrv_co_pread(s->data_file, host_offset, bytes, buf, 0);
2186 if (ret < 0) {
2187 goto fail;
2190 if (qcow2_co_decrypt(bs, host_offset, offset, buf, bytes) < 0)
2192 ret = -EIO;
2193 goto fail;
2195 qemu_iovec_from_buf(qiov, qiov_offset, buf, bytes);
2197 fail:
2198 qemu_vfree(buf);
2200 return ret;
2203 typedef struct Qcow2AioTask {
2204 AioTask task;
2206 BlockDriverState *bs;
2207 QCow2SubclusterType subcluster_type; /* only for read */
2208 uint64_t host_offset; /* or l2_entry for compressed read */
2209 uint64_t offset;
2210 uint64_t bytes;
2211 QEMUIOVector *qiov;
2212 uint64_t qiov_offset;
2213 QCowL2Meta *l2meta; /* only for write */
2214 } Qcow2AioTask;
2216 static coroutine_fn int qcow2_co_preadv_task_entry(AioTask *task);
2217 static coroutine_fn int qcow2_add_task(BlockDriverState *bs,
2218 AioTaskPool *pool,
2219 AioTaskFunc func,
2220 QCow2SubclusterType subcluster_type,
2221 uint64_t host_offset,
2222 uint64_t offset,
2223 uint64_t bytes,
2224 QEMUIOVector *qiov,
2225 size_t qiov_offset,
2226 QCowL2Meta *l2meta)
2228 Qcow2AioTask local_task;
2229 Qcow2AioTask *task = pool ? g_new(Qcow2AioTask, 1) : &local_task;
2231 *task = (Qcow2AioTask) {
2232 .task.func = func,
2233 .bs = bs,
2234 .subcluster_type = subcluster_type,
2235 .qiov = qiov,
2236 .host_offset = host_offset,
2237 .offset = offset,
2238 .bytes = bytes,
2239 .qiov_offset = qiov_offset,
2240 .l2meta = l2meta,
2243 trace_qcow2_add_task(qemu_coroutine_self(), bs, pool,
2244 func == qcow2_co_preadv_task_entry ? "read" : "write",
2245 subcluster_type, host_offset, offset, bytes,
2246 qiov, qiov_offset);
2248 if (!pool) {
2249 return func(&task->task);
2252 aio_task_pool_start_task(pool, &task->task);
2254 return 0;
2257 static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs,
2258 QCow2SubclusterType subc_type,
2259 uint64_t host_offset,
2260 uint64_t offset, uint64_t bytes,
2261 QEMUIOVector *qiov,
2262 size_t qiov_offset)
2264 BDRVQcow2State *s = bs->opaque;
2266 switch (subc_type) {
2267 case QCOW2_SUBCLUSTER_ZERO_PLAIN:
2268 case QCOW2_SUBCLUSTER_ZERO_ALLOC:
2269 /* Both zero types are handled in qcow2_co_preadv_part */
2270 g_assert_not_reached();
2272 case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN:
2273 case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC:
2274 assert(bs->backing); /* otherwise handled in qcow2_co_preadv_part */
2276 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
2277 return bdrv_co_preadv_part(bs->backing, offset, bytes,
2278 qiov, qiov_offset, 0);
2280 case QCOW2_SUBCLUSTER_COMPRESSED:
2281 return qcow2_co_preadv_compressed(bs, host_offset,
2282 offset, bytes, qiov, qiov_offset);
2284 case QCOW2_SUBCLUSTER_NORMAL:
2285 if (bs->encrypted) {
2286 return qcow2_co_preadv_encrypted(bs, host_offset,
2287 offset, bytes, qiov, qiov_offset);
2290 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
2291 return bdrv_co_preadv_part(s->data_file, host_offset,
2292 bytes, qiov, qiov_offset, 0);
2294 default:
2295 g_assert_not_reached();
2298 g_assert_not_reached();
2301 static coroutine_fn int qcow2_co_preadv_task_entry(AioTask *task)
2303 Qcow2AioTask *t = container_of(task, Qcow2AioTask, task);
2305 assert(!t->l2meta);
2307 return qcow2_co_preadv_task(t->bs, t->subcluster_type,
2308 t->host_offset, t->offset, t->bytes,
2309 t->qiov, t->qiov_offset);
2312 static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs,
2313 int64_t offset, int64_t bytes,
2314 QEMUIOVector *qiov,
2315 size_t qiov_offset,
2316 BdrvRequestFlags flags)
2318 BDRVQcow2State *s = bs->opaque;
2319 int ret = 0;
2320 unsigned int cur_bytes; /* number of bytes in current iteration */
2321 uint64_t host_offset = 0;
2322 QCow2SubclusterType type;
2323 AioTaskPool *aio = NULL;
2325 while (bytes != 0 && aio_task_pool_status(aio) == 0) {
2326 /* prepare next request */
2327 cur_bytes = MIN(bytes, INT_MAX);
2328 if (s->crypto) {
2329 cur_bytes = MIN(cur_bytes,
2330 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
2333 qemu_co_mutex_lock(&s->lock);
2334 ret = qcow2_get_host_offset(bs, offset, &cur_bytes,
2335 &host_offset, &type);
2336 qemu_co_mutex_unlock(&s->lock);
2337 if (ret < 0) {
2338 goto out;
2341 if (type == QCOW2_SUBCLUSTER_ZERO_PLAIN ||
2342 type == QCOW2_SUBCLUSTER_ZERO_ALLOC ||
2343 (type == QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN && !bs->backing) ||
2344 (type == QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC && !bs->backing))
2346 qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
2347 } else {
2348 if (!aio && cur_bytes != bytes) {
2349 aio = aio_task_pool_new(QCOW2_MAX_WORKERS);
2351 ret = qcow2_add_task(bs, aio, qcow2_co_preadv_task_entry, type,
2352 host_offset, offset, cur_bytes,
2353 qiov, qiov_offset, NULL);
2354 if (ret < 0) {
2355 goto out;
2359 bytes -= cur_bytes;
2360 offset += cur_bytes;
2361 qiov_offset += cur_bytes;
2364 out:
2365 if (aio) {
2366 aio_task_pool_wait_all(aio);
2367 if (ret == 0) {
2368 ret = aio_task_pool_status(aio);
2370 g_free(aio);
2373 return ret;
2376 /* Check if it's possible to merge a write request with the writing of
2377 * the data from the COW regions */
2378 static bool merge_cow(uint64_t offset, unsigned bytes,
2379 QEMUIOVector *qiov, size_t qiov_offset,
2380 QCowL2Meta *l2meta)
2382 QCowL2Meta *m;
2384 for (m = l2meta; m != NULL; m = m->next) {
2385 /* If both COW regions are empty then there's nothing to merge */
2386 if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) {
2387 continue;
2390 /* If COW regions are handled already, skip this too */
2391 if (m->skip_cow) {
2392 continue;
2396 * The write request should start immediately after the first
2397 * COW region. This does not always happen because the area
2398 * touched by the request can be larger than the one defined
2399 * by @m (a single request can span an area consisting of a
2400 * mix of previously unallocated and allocated clusters, that
2401 * is why @l2meta is a list).
2403 if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) {
2404 /* In this case the request starts before this region */
2405 assert(offset < l2meta_cow_start(m));
2406 assert(m->cow_start.nb_bytes == 0);
2407 continue;
2410 /* The write request should end immediately before the second
2411 * COW region (see above for why it does not always happen) */
2412 if (m->offset + m->cow_end.offset != offset + bytes) {
2413 assert(offset + bytes > m->offset + m->cow_end.offset);
2414 assert(m->cow_end.nb_bytes == 0);
2415 continue;
2418 /* Make sure that adding both COW regions to the QEMUIOVector
2419 * does not exceed IOV_MAX */
2420 if (qemu_iovec_subvec_niov(qiov, qiov_offset, bytes) > IOV_MAX - 2) {
2421 continue;
2424 m->data_qiov = qiov;
2425 m->data_qiov_offset = qiov_offset;
2426 return true;
2429 return false;
2433 * Return 1 if the COW regions read as zeroes, 0 if not, < 0 on error.
2434 * Note that returning 0 does not guarantee non-zero data.
2436 static int is_zero_cow(BlockDriverState *bs, QCowL2Meta *m)
2439 * This check is designed for optimization shortcut so it must be
2440 * efficient.
2441 * Instead of is_zero(), use bdrv_co_is_zero_fast() as it is
2442 * faster (but not as accurate and can result in false negatives).
2444 int ret = bdrv_co_is_zero_fast(bs, m->offset + m->cow_start.offset,
2445 m->cow_start.nb_bytes);
2446 if (ret <= 0) {
2447 return ret;
2450 return bdrv_co_is_zero_fast(bs, m->offset + m->cow_end.offset,
2451 m->cow_end.nb_bytes);
2454 static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta)
2456 BDRVQcow2State *s = bs->opaque;
2457 QCowL2Meta *m;
2459 if (!(s->data_file->bs->supported_zero_flags & BDRV_REQ_NO_FALLBACK)) {
2460 return 0;
2463 if (bs->encrypted) {
2464 return 0;
2467 for (m = l2meta; m != NULL; m = m->next) {
2468 int ret;
2469 uint64_t start_offset = m->alloc_offset + m->cow_start.offset;
2470 unsigned nb_bytes = m->cow_end.offset + m->cow_end.nb_bytes -
2471 m->cow_start.offset;
2473 if (!m->cow_start.nb_bytes && !m->cow_end.nb_bytes) {
2474 continue;
2477 ret = is_zero_cow(bs, m);
2478 if (ret < 0) {
2479 return ret;
2480 } else if (ret == 0) {
2481 continue;
2485 * instead of writing zero COW buffers,
2486 * efficiently zero out the whole clusters
2489 ret = qcow2_pre_write_overlap_check(bs, 0, start_offset, nb_bytes,
2490 true);
2491 if (ret < 0) {
2492 return ret;
2495 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_SPACE);
2496 ret = bdrv_co_pwrite_zeroes(s->data_file, start_offset, nb_bytes,
2497 BDRV_REQ_NO_FALLBACK);
2498 if (ret < 0) {
2499 if (ret != -ENOTSUP && ret != -EAGAIN) {
2500 return ret;
2502 continue;
2505 trace_qcow2_skip_cow(qemu_coroutine_self(), m->offset, m->nb_clusters);
2506 m->skip_cow = true;
2508 return 0;
2512 * qcow2_co_pwritev_task
2513 * Called with s->lock unlocked
2514 * l2meta - if not NULL, qcow2_co_pwritev_task() will consume it. Caller must
2515 * not use it somehow after qcow2_co_pwritev_task() call
2517 static coroutine_fn int qcow2_co_pwritev_task(BlockDriverState *bs,
2518 uint64_t host_offset,
2519 uint64_t offset, uint64_t bytes,
2520 QEMUIOVector *qiov,
2521 uint64_t qiov_offset,
2522 QCowL2Meta *l2meta)
2524 int ret;
2525 BDRVQcow2State *s = bs->opaque;
2526 void *crypt_buf = NULL;
2527 QEMUIOVector encrypted_qiov;
2529 if (bs->encrypted) {
2530 assert(s->crypto);
2531 assert(bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
2532 crypt_buf = qemu_try_blockalign(bs->file->bs, bytes);
2533 if (crypt_buf == NULL) {
2534 ret = -ENOMEM;
2535 goto out_unlocked;
2537 qemu_iovec_to_buf(qiov, qiov_offset, crypt_buf, bytes);
2539 if (qcow2_co_encrypt(bs, host_offset, offset, crypt_buf, bytes) < 0) {
2540 ret = -EIO;
2541 goto out_unlocked;
2544 qemu_iovec_init_buf(&encrypted_qiov, crypt_buf, bytes);
2545 qiov = &encrypted_qiov;
2546 qiov_offset = 0;
2549 /* Try to efficiently initialize the physical space with zeroes */
2550 ret = handle_alloc_space(bs, l2meta);
2551 if (ret < 0) {
2552 goto out_unlocked;
2556 * If we need to do COW, check if it's possible to merge the
2557 * writing of the guest data together with that of the COW regions.
2558 * If it's not possible (or not necessary) then write the
2559 * guest data now.
2561 if (!merge_cow(offset, bytes, qiov, qiov_offset, l2meta)) {
2562 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
2563 trace_qcow2_writev_data(qemu_coroutine_self(), host_offset);
2564 ret = bdrv_co_pwritev_part(s->data_file, host_offset,
2565 bytes, qiov, qiov_offset, 0);
2566 if (ret < 0) {
2567 goto out_unlocked;
2571 qemu_co_mutex_lock(&s->lock);
2573 ret = qcow2_handle_l2meta(bs, &l2meta, true);
2574 goto out_locked;
2576 out_unlocked:
2577 qemu_co_mutex_lock(&s->lock);
2579 out_locked:
2580 qcow2_handle_l2meta(bs, &l2meta, false);
2581 qemu_co_mutex_unlock(&s->lock);
2583 qemu_vfree(crypt_buf);
2585 return ret;
2588 static coroutine_fn int qcow2_co_pwritev_task_entry(AioTask *task)
2590 Qcow2AioTask *t = container_of(task, Qcow2AioTask, task);
2592 assert(!t->subcluster_type);
2594 return qcow2_co_pwritev_task(t->bs, t->host_offset,
2595 t->offset, t->bytes, t->qiov, t->qiov_offset,
2596 t->l2meta);
2599 static coroutine_fn int qcow2_co_pwritev_part(
2600 BlockDriverState *bs, int64_t offset, int64_t bytes,
2601 QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags)
2603 BDRVQcow2State *s = bs->opaque;
2604 int offset_in_cluster;
2605 int ret;
2606 unsigned int cur_bytes; /* number of sectors in current iteration */
2607 uint64_t host_offset;
2608 QCowL2Meta *l2meta = NULL;
2609 AioTaskPool *aio = NULL;
2611 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes);
2613 while (bytes != 0 && aio_task_pool_status(aio) == 0) {
2615 l2meta = NULL;
2617 trace_qcow2_writev_start_part(qemu_coroutine_self());
2618 offset_in_cluster = offset_into_cluster(s, offset);
2619 cur_bytes = MIN(bytes, INT_MAX);
2620 if (bs->encrypted) {
2621 cur_bytes = MIN(cur_bytes,
2622 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
2623 - offset_in_cluster);
2626 qemu_co_mutex_lock(&s->lock);
2628 ret = qcow2_alloc_host_offset(bs, offset, &cur_bytes,
2629 &host_offset, &l2meta);
2630 if (ret < 0) {
2631 goto out_locked;
2634 ret = qcow2_pre_write_overlap_check(bs, 0, host_offset,
2635 cur_bytes, true);
2636 if (ret < 0) {
2637 goto out_locked;
2640 qemu_co_mutex_unlock(&s->lock);
2642 if (!aio && cur_bytes != bytes) {
2643 aio = aio_task_pool_new(QCOW2_MAX_WORKERS);
2645 ret = qcow2_add_task(bs, aio, qcow2_co_pwritev_task_entry, 0,
2646 host_offset, offset,
2647 cur_bytes, qiov, qiov_offset, l2meta);
2648 l2meta = NULL; /* l2meta is consumed by qcow2_co_pwritev_task() */
2649 if (ret < 0) {
2650 goto fail_nometa;
2653 bytes -= cur_bytes;
2654 offset += cur_bytes;
2655 qiov_offset += cur_bytes;
2656 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes);
2658 ret = 0;
2660 qemu_co_mutex_lock(&s->lock);
2662 out_locked:
2663 qcow2_handle_l2meta(bs, &l2meta, false);
2665 qemu_co_mutex_unlock(&s->lock);
2667 fail_nometa:
2668 if (aio) {
2669 aio_task_pool_wait_all(aio);
2670 if (ret == 0) {
2671 ret = aio_task_pool_status(aio);
2673 g_free(aio);
2676 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
2678 return ret;
2681 static int qcow2_inactivate(BlockDriverState *bs)
2683 BDRVQcow2State *s = bs->opaque;
2684 int ret, result = 0;
2685 Error *local_err = NULL;
2687 qcow2_store_persistent_dirty_bitmaps(bs, true, &local_err);
2688 if (local_err != NULL) {
2689 result = -EINVAL;
2690 error_reportf_err(local_err, "Lost persistent bitmaps during "
2691 "inactivation of node '%s': ",
2692 bdrv_get_device_or_node_name(bs));
2695 ret = qcow2_cache_flush(bs, s->l2_table_cache);
2696 if (ret) {
2697 result = ret;
2698 error_report("Failed to flush the L2 table cache: %s",
2699 strerror(-ret));
2702 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
2703 if (ret) {
2704 result = ret;
2705 error_report("Failed to flush the refcount block cache: %s",
2706 strerror(-ret));
2709 if (result == 0) {
2710 qcow2_mark_clean(bs);
2713 return result;
2716 static void qcow2_close(BlockDriverState *bs)
2718 BDRVQcow2State *s = bs->opaque;
2719 qemu_vfree(s->l1_table);
2720 /* else pre-write overlap checks in cache_destroy may crash */
2721 s->l1_table = NULL;
2723 if (!(s->flags & BDRV_O_INACTIVE)) {
2724 qcow2_inactivate(bs);
2727 cache_clean_timer_del(bs);
2728 qcow2_cache_destroy(s->l2_table_cache);
2729 qcow2_cache_destroy(s->refcount_block_cache);
2731 qcrypto_block_free(s->crypto);
2732 s->crypto = NULL;
2733 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts);
2735 g_free(s->unknown_header_fields);
2736 cleanup_unknown_header_ext(bs);
2738 g_free(s->image_data_file);
2739 g_free(s->image_backing_file);
2740 g_free(s->image_backing_format);
2742 if (has_data_file(bs)) {
2743 bdrv_unref_child(bs, s->data_file);
2744 s->data_file = NULL;
2747 qcow2_refcount_close(bs);
2748 qcow2_free_snapshots(bs);
2751 static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs,
2752 Error **errp)
2754 ERRP_GUARD();
2755 BDRVQcow2State *s = bs->opaque;
2756 int flags = s->flags;
2757 QCryptoBlock *crypto = NULL;
2758 QDict *options;
2759 int ret;
2762 * Backing files are read-only which makes all of their metadata immutable,
2763 * that means we don't have to worry about reopening them here.
2766 crypto = s->crypto;
2767 s->crypto = NULL;
2769 qcow2_close(bs);
2771 memset(s, 0, sizeof(BDRVQcow2State));
2772 options = qdict_clone_shallow(bs->options);
2774 flags &= ~BDRV_O_INACTIVE;
2775 qemu_co_mutex_lock(&s->lock);
2776 ret = qcow2_do_open(bs, options, flags, errp);
2777 qemu_co_mutex_unlock(&s->lock);
2778 qobject_unref(options);
2779 if (ret < 0) {
2780 error_prepend(errp, "Could not reopen qcow2 layer: ");
2781 bs->drv = NULL;
2782 return;
2785 s->crypto = crypto;
2788 static size_t header_ext_add(char *buf, uint32_t magic, const void *s,
2789 size_t len, size_t buflen)
2791 QCowExtension *ext_backing_fmt = (QCowExtension*) buf;
2792 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7);
2794 if (buflen < ext_len) {
2795 return -ENOSPC;
2798 *ext_backing_fmt = (QCowExtension) {
2799 .magic = cpu_to_be32(magic),
2800 .len = cpu_to_be32(len),
2803 if (len) {
2804 memcpy(buf + sizeof(QCowExtension), s, len);
2807 return ext_len;
2811 * Updates the qcow2 header, including the variable length parts of it, i.e.
2812 * the backing file name and all extensions. qcow2 was not designed to allow
2813 * such changes, so if we run out of space (we can only use the first cluster)
2814 * this function may fail.
2816 * Returns 0 on success, -errno in error cases.
2818 int qcow2_update_header(BlockDriverState *bs)
2820 BDRVQcow2State *s = bs->opaque;
2821 QCowHeader *header;
2822 char *buf;
2823 size_t buflen = s->cluster_size;
2824 int ret;
2825 uint64_t total_size;
2826 uint32_t refcount_table_clusters;
2827 size_t header_length;
2828 Qcow2UnknownHeaderExtension *uext;
2830 buf = qemu_blockalign(bs, buflen);
2832 /* Header structure */
2833 header = (QCowHeader*) buf;
2835 if (buflen < sizeof(*header)) {
2836 ret = -ENOSPC;
2837 goto fail;
2840 header_length = sizeof(*header) + s->unknown_header_fields_size;
2841 total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
2842 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
2844 ret = validate_compression_type(s, NULL);
2845 if (ret) {
2846 goto fail;
2849 *header = (QCowHeader) {
2850 /* Version 2 fields */
2851 .magic = cpu_to_be32(QCOW_MAGIC),
2852 .version = cpu_to_be32(s->qcow_version),
2853 .backing_file_offset = 0,
2854 .backing_file_size = 0,
2855 .cluster_bits = cpu_to_be32(s->cluster_bits),
2856 .size = cpu_to_be64(total_size),
2857 .crypt_method = cpu_to_be32(s->crypt_method_header),
2858 .l1_size = cpu_to_be32(s->l1_size),
2859 .l1_table_offset = cpu_to_be64(s->l1_table_offset),
2860 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset),
2861 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters),
2862 .nb_snapshots = cpu_to_be32(s->nb_snapshots),
2863 .snapshots_offset = cpu_to_be64(s->snapshots_offset),
2865 /* Version 3 fields */
2866 .incompatible_features = cpu_to_be64(s->incompatible_features),
2867 .compatible_features = cpu_to_be64(s->compatible_features),
2868 .autoclear_features = cpu_to_be64(s->autoclear_features),
2869 .refcount_order = cpu_to_be32(s->refcount_order),
2870 .header_length = cpu_to_be32(header_length),
2871 .compression_type = s->compression_type,
2874 /* For older versions, write a shorter header */
2875 switch (s->qcow_version) {
2876 case 2:
2877 ret = offsetof(QCowHeader, incompatible_features);
2878 break;
2879 case 3:
2880 ret = sizeof(*header);
2881 break;
2882 default:
2883 ret = -EINVAL;
2884 goto fail;
2887 buf += ret;
2888 buflen -= ret;
2889 memset(buf, 0, buflen);
2891 /* Preserve any unknown field in the header */
2892 if (s->unknown_header_fields_size) {
2893 if (buflen < s->unknown_header_fields_size) {
2894 ret = -ENOSPC;
2895 goto fail;
2898 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size);
2899 buf += s->unknown_header_fields_size;
2900 buflen -= s->unknown_header_fields_size;
2903 /* Backing file format header extension */
2904 if (s->image_backing_format) {
2905 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT,
2906 s->image_backing_format,
2907 strlen(s->image_backing_format),
2908 buflen);
2909 if (ret < 0) {
2910 goto fail;
2913 buf += ret;
2914 buflen -= ret;
2917 /* External data file header extension */
2918 if (has_data_file(bs) && s->image_data_file) {
2919 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_DATA_FILE,
2920 s->image_data_file, strlen(s->image_data_file),
2921 buflen);
2922 if (ret < 0) {
2923 goto fail;
2926 buf += ret;
2927 buflen -= ret;
2930 /* Full disk encryption header pointer extension */
2931 if (s->crypto_header.offset != 0) {
2932 s->crypto_header.offset = cpu_to_be64(s->crypto_header.offset);
2933 s->crypto_header.length = cpu_to_be64(s->crypto_header.length);
2934 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER,
2935 &s->crypto_header, sizeof(s->crypto_header),
2936 buflen);
2937 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset);
2938 s->crypto_header.length = be64_to_cpu(s->crypto_header.length);
2939 if (ret < 0) {
2940 goto fail;
2942 buf += ret;
2943 buflen -= ret;
2947 * Feature table. A mere 8 feature names occupies 392 bytes, and
2948 * when coupled with the v3 minimum header of 104 bytes plus the
2949 * 8-byte end-of-extension marker, that would leave only 8 bytes
2950 * for a backing file name in an image with 512-byte clusters.
2951 * Thus, we choose to omit this header for cluster sizes 4k and
2952 * smaller.
2954 if (s->qcow_version >= 3 && s->cluster_size > 4096) {
2955 static const Qcow2Feature features[] = {
2957 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
2958 .bit = QCOW2_INCOMPAT_DIRTY_BITNR,
2959 .name = "dirty bit",
2962 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
2963 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR,
2964 .name = "corrupt bit",
2967 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
2968 .bit = QCOW2_INCOMPAT_DATA_FILE_BITNR,
2969 .name = "external data file",
2972 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
2973 .bit = QCOW2_INCOMPAT_COMPRESSION_BITNR,
2974 .name = "compression type",
2977 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
2978 .bit = QCOW2_INCOMPAT_EXTL2_BITNR,
2979 .name = "extended L2 entries",
2982 .type = QCOW2_FEAT_TYPE_COMPATIBLE,
2983 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
2984 .name = "lazy refcounts",
2987 .type = QCOW2_FEAT_TYPE_AUTOCLEAR,
2988 .bit = QCOW2_AUTOCLEAR_BITMAPS_BITNR,
2989 .name = "bitmaps",
2992 .type = QCOW2_FEAT_TYPE_AUTOCLEAR,
2993 .bit = QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR,
2994 .name = "raw external data",
2998 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
2999 features, sizeof(features), buflen);
3000 if (ret < 0) {
3001 goto fail;
3003 buf += ret;
3004 buflen -= ret;
3007 /* Bitmap extension */
3008 if (s->nb_bitmaps > 0) {
3009 Qcow2BitmapHeaderExt bitmaps_header = {
3010 .nb_bitmaps = cpu_to_be32(s->nb_bitmaps),
3011 .bitmap_directory_size =
3012 cpu_to_be64(s->bitmap_directory_size),
3013 .bitmap_directory_offset =
3014 cpu_to_be64(s->bitmap_directory_offset)
3016 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS,
3017 &bitmaps_header, sizeof(bitmaps_header),
3018 buflen);
3019 if (ret < 0) {
3020 goto fail;
3022 buf += ret;
3023 buflen -= ret;
3026 /* Keep unknown header extensions */
3027 QLIST_FOREACH(uext, &s->unknown_header_ext, next) {
3028 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen);
3029 if (ret < 0) {
3030 goto fail;
3033 buf += ret;
3034 buflen -= ret;
3037 /* End of header extensions */
3038 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen);
3039 if (ret < 0) {
3040 goto fail;
3043 buf += ret;
3044 buflen -= ret;
3046 /* Backing file name */
3047 if (s->image_backing_file) {
3048 size_t backing_file_len = strlen(s->image_backing_file);
3050 if (buflen < backing_file_len) {
3051 ret = -ENOSPC;
3052 goto fail;
3055 /* Using strncpy is ok here, since buf is not NUL-terminated. */
3056 strncpy(buf, s->image_backing_file, buflen);
3058 header->backing_file_offset = cpu_to_be64(buf - ((char*) header));
3059 header->backing_file_size = cpu_to_be32(backing_file_len);
3062 /* Write the new header */
3063 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size);
3064 if (ret < 0) {
3065 goto fail;
3068 ret = 0;
3069 fail:
3070 qemu_vfree(header);
3071 return ret;
3074 static int qcow2_change_backing_file(BlockDriverState *bs,
3075 const char *backing_file, const char *backing_fmt)
3077 BDRVQcow2State *s = bs->opaque;
3079 /* Adding a backing file means that the external data file alone won't be
3080 * enough to make sense of the content */
3081 if (backing_file && data_file_is_raw(bs)) {
3082 return -EINVAL;
3085 if (backing_file && strlen(backing_file) > 1023) {
3086 return -EINVAL;
3089 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
3090 backing_file ?: "");
3091 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
3092 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
3094 g_free(s->image_backing_file);
3095 g_free(s->image_backing_format);
3097 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL;
3098 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL;
3100 return qcow2_update_header(bs);
3103 static int qcow2_set_up_encryption(BlockDriverState *bs,
3104 QCryptoBlockCreateOptions *cryptoopts,
3105 Error **errp)
3107 BDRVQcow2State *s = bs->opaque;
3108 QCryptoBlock *crypto = NULL;
3109 int fmt, ret;
3111 switch (cryptoopts->format) {
3112 case Q_CRYPTO_BLOCK_FORMAT_LUKS:
3113 fmt = QCOW_CRYPT_LUKS;
3114 break;
3115 case Q_CRYPTO_BLOCK_FORMAT_QCOW:
3116 fmt = QCOW_CRYPT_AES;
3117 break;
3118 default:
3119 error_setg(errp, "Crypto format not supported in qcow2");
3120 return -EINVAL;
3123 s->crypt_method_header = fmt;
3125 crypto = qcrypto_block_create(cryptoopts, "encrypt.",
3126 qcow2_crypto_hdr_init_func,
3127 qcow2_crypto_hdr_write_func,
3128 bs, errp);
3129 if (!crypto) {
3130 return -EINVAL;
3133 ret = qcow2_update_header(bs);
3134 if (ret < 0) {
3135 error_setg_errno(errp, -ret, "Could not write encryption header");
3136 goto out;
3139 ret = 0;
3140 out:
3141 qcrypto_block_free(crypto);
3142 return ret;
3146 * Preallocates metadata structures for data clusters between @offset (in the
3147 * guest disk) and @new_length (which is thus generally the new guest disk
3148 * size).
3150 * Returns: 0 on success, -errno on failure.
3152 static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset,
3153 uint64_t new_length, PreallocMode mode,
3154 Error **errp)
3156 BDRVQcow2State *s = bs->opaque;
3157 uint64_t bytes;
3158 uint64_t host_offset = 0;
3159 int64_t file_length;
3160 unsigned int cur_bytes;
3161 int ret;
3162 QCowL2Meta *meta = NULL, *m;
3164 assert(offset <= new_length);
3165 bytes = new_length - offset;
3167 while (bytes) {
3168 cur_bytes = MIN(bytes, QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size));
3169 ret = qcow2_alloc_host_offset(bs, offset, &cur_bytes,
3170 &host_offset, &meta);
3171 if (ret < 0) {
3172 error_setg_errno(errp, -ret, "Allocating clusters failed");
3173 goto out;
3176 for (m = meta; m != NULL; m = m->next) {
3177 m->prealloc = true;
3180 ret = qcow2_handle_l2meta(bs, &meta, true);
3181 if (ret < 0) {
3182 error_setg_errno(errp, -ret, "Mapping clusters failed");
3183 goto out;
3186 /* TODO Preallocate data if requested */
3188 bytes -= cur_bytes;
3189 offset += cur_bytes;
3193 * It is expected that the image file is large enough to actually contain
3194 * all of the allocated clusters (otherwise we get failing reads after
3195 * EOF). Extend the image to the last allocated sector.
3197 file_length = bdrv_getlength(s->data_file->bs);
3198 if (file_length < 0) {
3199 error_setg_errno(errp, -file_length, "Could not get file size");
3200 ret = file_length;
3201 goto out;
3204 if (host_offset + cur_bytes > file_length) {
3205 if (mode == PREALLOC_MODE_METADATA) {
3206 mode = PREALLOC_MODE_OFF;
3208 ret = bdrv_co_truncate(s->data_file, host_offset + cur_bytes, false,
3209 mode, 0, errp);
3210 if (ret < 0) {
3211 goto out;
3215 ret = 0;
3217 out:
3218 qcow2_handle_l2meta(bs, &meta, false);
3219 return ret;
3222 /* qcow2_refcount_metadata_size:
3223 * @clusters: number of clusters to refcount (including data and L1/L2 tables)
3224 * @cluster_size: size of a cluster, in bytes
3225 * @refcount_order: refcount bits power-of-2 exponent
3226 * @generous_increase: allow for the refcount table to be 1.5x as large as it
3227 * needs to be
3229 * Returns: Number of bytes required for refcount blocks and table metadata.
3231 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size,
3232 int refcount_order, bool generous_increase,
3233 uint64_t *refblock_count)
3236 * Every host cluster is reference-counted, including metadata (even
3237 * refcount metadata is recursively included).
3239 * An accurate formula for the size of refcount metadata size is difficult
3240 * to derive. An easier method of calculation is finding the fixed point
3241 * where no further refcount blocks or table clusters are required to
3242 * reference count every cluster.
3244 int64_t blocks_per_table_cluster = cluster_size / REFTABLE_ENTRY_SIZE;
3245 int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order);
3246 int64_t table = 0; /* number of refcount table clusters */
3247 int64_t blocks = 0; /* number of refcount block clusters */
3248 int64_t last;
3249 int64_t n = 0;
3251 do {
3252 last = n;
3253 blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block);
3254 table = DIV_ROUND_UP(blocks, blocks_per_table_cluster);
3255 n = clusters + blocks + table;
3257 if (n == last && generous_increase) {
3258 clusters += DIV_ROUND_UP(table, 2);
3259 n = 0; /* force another loop */
3260 generous_increase = false;
3262 } while (n != last);
3264 if (refblock_count) {
3265 *refblock_count = blocks;
3268 return (blocks + table) * cluster_size;
3272 * qcow2_calc_prealloc_size:
3273 * @total_size: virtual disk size in bytes
3274 * @cluster_size: cluster size in bytes
3275 * @refcount_order: refcount bits power-of-2 exponent
3276 * @extended_l2: true if the image has extended L2 entries
3278 * Returns: Total number of bytes required for the fully allocated image
3279 * (including metadata).
3281 static int64_t qcow2_calc_prealloc_size(int64_t total_size,
3282 size_t cluster_size,
3283 int refcount_order,
3284 bool extended_l2)
3286 int64_t meta_size = 0;
3287 uint64_t nl1e, nl2e;
3288 int64_t aligned_total_size = ROUND_UP(total_size, cluster_size);
3289 size_t l2e_size = extended_l2 ? L2E_SIZE_EXTENDED : L2E_SIZE_NORMAL;
3291 /* header: 1 cluster */
3292 meta_size += cluster_size;
3294 /* total size of L2 tables */
3295 nl2e = aligned_total_size / cluster_size;
3296 nl2e = ROUND_UP(nl2e, cluster_size / l2e_size);
3297 meta_size += nl2e * l2e_size;
3299 /* total size of L1 tables */
3300 nl1e = nl2e * l2e_size / cluster_size;
3301 nl1e = ROUND_UP(nl1e, cluster_size / L1E_SIZE);
3302 meta_size += nl1e * L1E_SIZE;
3304 /* total size of refcount table and blocks */
3305 meta_size += qcow2_refcount_metadata_size(
3306 (meta_size + aligned_total_size) / cluster_size,
3307 cluster_size, refcount_order, false, NULL);
3309 return meta_size + aligned_total_size;
3312 static bool validate_cluster_size(size_t cluster_size, bool extended_l2,
3313 Error **errp)
3315 int cluster_bits = ctz32(cluster_size);
3316 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
3317 (1 << cluster_bits) != cluster_size)
3319 error_setg(errp, "Cluster size must be a power of two between %d and "
3320 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
3321 return false;
3324 if (extended_l2) {
3325 unsigned min_cluster_size =
3326 (1 << MIN_CLUSTER_BITS) * QCOW_EXTL2_SUBCLUSTERS_PER_CLUSTER;
3327 if (cluster_size < min_cluster_size) {
3328 error_setg(errp, "Extended L2 entries are only supported with "
3329 "cluster sizes of at least %u bytes", min_cluster_size);
3330 return false;
3334 return true;
3337 static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, bool extended_l2,
3338 Error **errp)
3340 size_t cluster_size;
3342 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
3343 DEFAULT_CLUSTER_SIZE);
3344 if (!validate_cluster_size(cluster_size, extended_l2, errp)) {
3345 return 0;
3347 return cluster_size;
3350 static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp)
3352 char *buf;
3353 int ret;
3355 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL);
3356 if (!buf) {
3357 ret = 3; /* default */
3358 } else if (!strcmp(buf, "0.10")) {
3359 ret = 2;
3360 } else if (!strcmp(buf, "1.1")) {
3361 ret = 3;
3362 } else {
3363 error_setg(errp, "Invalid compatibility level: '%s'", buf);
3364 ret = -EINVAL;
3366 g_free(buf);
3367 return ret;
3370 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version,
3371 Error **errp)
3373 uint64_t refcount_bits;
3375 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16);
3376 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) {
3377 error_setg(errp, "Refcount width must be a power of two and may not "
3378 "exceed 64 bits");
3379 return 0;
3382 if (version < 3 && refcount_bits != 16) {
3383 error_setg(errp, "Different refcount widths than 16 bits require "
3384 "compatibility level 1.1 or above (use compat=1.1 or "
3385 "greater)");
3386 return 0;
3389 return refcount_bits;
3392 static int coroutine_fn
3393 qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
3395 BlockdevCreateOptionsQcow2 *qcow2_opts;
3396 QDict *options;
3399 * Open the image file and write a minimal qcow2 header.
3401 * We keep things simple and start with a zero-sized image. We also
3402 * do without refcount blocks or a L1 table for now. We'll fix the
3403 * inconsistency later.
3405 * We do need a refcount table because growing the refcount table means
3406 * allocating two new refcount blocks - the second of which would be at
3407 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
3408 * size for any qcow2 image.
3410 BlockBackend *blk = NULL;
3411 BlockDriverState *bs = NULL;
3412 BlockDriverState *data_bs = NULL;
3413 QCowHeader *header;
3414 size_t cluster_size;
3415 int version;
3416 int refcount_order;
3417 uint64_t *refcount_table;
3418 int ret;
3419 uint8_t compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
3421 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2);
3422 qcow2_opts = &create_options->u.qcow2;
3424 bs = bdrv_open_blockdev_ref(qcow2_opts->file, errp);
3425 if (bs == NULL) {
3426 return -EIO;
3429 /* Validate options and set default values */
3430 if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) {
3431 error_setg(errp, "Image size must be a multiple of %u bytes",
3432 (unsigned) BDRV_SECTOR_SIZE);
3433 ret = -EINVAL;
3434 goto out;
3437 if (qcow2_opts->has_version) {
3438 switch (qcow2_opts->version) {
3439 case BLOCKDEV_QCOW2_VERSION_V2:
3440 version = 2;
3441 break;
3442 case BLOCKDEV_QCOW2_VERSION_V3:
3443 version = 3;
3444 break;
3445 default:
3446 g_assert_not_reached();
3448 } else {
3449 version = 3;
3452 if (qcow2_opts->has_cluster_size) {
3453 cluster_size = qcow2_opts->cluster_size;
3454 } else {
3455 cluster_size = DEFAULT_CLUSTER_SIZE;
3458 if (!qcow2_opts->has_extended_l2) {
3459 qcow2_opts->extended_l2 = false;
3461 if (qcow2_opts->extended_l2) {
3462 if (version < 3) {
3463 error_setg(errp, "Extended L2 entries are only supported with "
3464 "compatibility level 1.1 and above (use version=v3 or "
3465 "greater)");
3466 ret = -EINVAL;
3467 goto out;
3471 if (!validate_cluster_size(cluster_size, qcow2_opts->extended_l2, errp)) {
3472 ret = -EINVAL;
3473 goto out;
3476 if (!qcow2_opts->has_preallocation) {
3477 qcow2_opts->preallocation = PREALLOC_MODE_OFF;
3479 if (qcow2_opts->has_backing_file &&
3480 qcow2_opts->preallocation != PREALLOC_MODE_OFF &&
3481 !qcow2_opts->extended_l2)
3483 error_setg(errp, "Backing file and preallocation can only be used at "
3484 "the same time if extended_l2 is on");
3485 ret = -EINVAL;
3486 goto out;
3488 if (qcow2_opts->has_backing_fmt && !qcow2_opts->has_backing_file) {
3489 error_setg(errp, "Backing format cannot be used without backing file");
3490 ret = -EINVAL;
3491 goto out;
3494 if (!qcow2_opts->has_lazy_refcounts) {
3495 qcow2_opts->lazy_refcounts = false;
3497 if (version < 3 && qcow2_opts->lazy_refcounts) {
3498 error_setg(errp, "Lazy refcounts only supported with compatibility "
3499 "level 1.1 and above (use version=v3 or greater)");
3500 ret = -EINVAL;
3501 goto out;
3504 if (!qcow2_opts->has_refcount_bits) {
3505 qcow2_opts->refcount_bits = 16;
3507 if (qcow2_opts->refcount_bits > 64 ||
3508 !is_power_of_2(qcow2_opts->refcount_bits))
3510 error_setg(errp, "Refcount width must be a power of two and may not "
3511 "exceed 64 bits");
3512 ret = -EINVAL;
3513 goto out;
3515 if (version < 3 && qcow2_opts->refcount_bits != 16) {
3516 error_setg(errp, "Different refcount widths than 16 bits require "
3517 "compatibility level 1.1 or above (use version=v3 or "
3518 "greater)");
3519 ret = -EINVAL;
3520 goto out;
3522 refcount_order = ctz32(qcow2_opts->refcount_bits);
3524 if (qcow2_opts->data_file_raw && !qcow2_opts->data_file) {
3525 error_setg(errp, "data-file-raw requires data-file");
3526 ret = -EINVAL;
3527 goto out;
3529 if (qcow2_opts->data_file_raw && qcow2_opts->has_backing_file) {
3530 error_setg(errp, "Backing file and data-file-raw cannot be used at "
3531 "the same time");
3532 ret = -EINVAL;
3533 goto out;
3535 if (qcow2_opts->data_file_raw &&
3536 qcow2_opts->preallocation == PREALLOC_MODE_OFF)
3539 * data-file-raw means that "the external data file can be
3540 * read as a consistent standalone raw image without looking
3541 * at the qcow2 metadata." It does not say that the metadata
3542 * must be ignored, though (and the qcow2 driver in fact does
3543 * not ignore it), so the L1/L2 tables must be present and
3544 * give a 1:1 mapping, so you get the same result regardless
3545 * of whether you look at the metadata or whether you ignore
3546 * it.
3548 qcow2_opts->preallocation = PREALLOC_MODE_METADATA;
3551 * Cannot use preallocation with backing files, but giving a
3552 * backing file when specifying data_file_raw is an error
3553 * anyway.
3555 assert(!qcow2_opts->has_backing_file);
3558 if (qcow2_opts->data_file) {
3559 if (version < 3) {
3560 error_setg(errp, "External data files are only supported with "
3561 "compatibility level 1.1 and above (use version=v3 or "
3562 "greater)");
3563 ret = -EINVAL;
3564 goto out;
3566 data_bs = bdrv_open_blockdev_ref(qcow2_opts->data_file, errp);
3567 if (data_bs == NULL) {
3568 ret = -EIO;
3569 goto out;
3573 if (qcow2_opts->has_compression_type &&
3574 qcow2_opts->compression_type != QCOW2_COMPRESSION_TYPE_ZLIB) {
3576 ret = -EINVAL;
3578 if (version < 3) {
3579 error_setg(errp, "Non-zlib compression type is only supported with "
3580 "compatibility level 1.1 and above (use version=v3 or "
3581 "greater)");
3582 goto out;
3585 switch (qcow2_opts->compression_type) {
3586 #ifdef CONFIG_ZSTD
3587 case QCOW2_COMPRESSION_TYPE_ZSTD:
3588 break;
3589 #endif
3590 default:
3591 error_setg(errp, "Unknown compression type");
3592 goto out;
3595 compression_type = qcow2_opts->compression_type;
3598 /* Create BlockBackend to write to the image */
3599 blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL,
3600 errp);
3601 if (!blk) {
3602 ret = -EPERM;
3603 goto out;
3605 blk_set_allow_write_beyond_eof(blk, true);
3607 /* Write the header */
3608 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header));
3609 header = g_malloc0(cluster_size);
3610 *header = (QCowHeader) {
3611 .magic = cpu_to_be32(QCOW_MAGIC),
3612 .version = cpu_to_be32(version),
3613 .cluster_bits = cpu_to_be32(ctz32(cluster_size)),
3614 .size = cpu_to_be64(0),
3615 .l1_table_offset = cpu_to_be64(0),
3616 .l1_size = cpu_to_be32(0),
3617 .refcount_table_offset = cpu_to_be64(cluster_size),
3618 .refcount_table_clusters = cpu_to_be32(1),
3619 .refcount_order = cpu_to_be32(refcount_order),
3620 /* don't deal with endianness since compression_type is 1 byte long */
3621 .compression_type = compression_type,
3622 .header_length = cpu_to_be32(sizeof(*header)),
3625 /* We'll update this to correct value later */
3626 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
3628 if (qcow2_opts->lazy_refcounts) {
3629 header->compatible_features |=
3630 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS);
3632 if (data_bs) {
3633 header->incompatible_features |=
3634 cpu_to_be64(QCOW2_INCOMPAT_DATA_FILE);
3636 if (qcow2_opts->data_file_raw) {
3637 header->autoclear_features |=
3638 cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW);
3640 if (compression_type != QCOW2_COMPRESSION_TYPE_ZLIB) {
3641 header->incompatible_features |=
3642 cpu_to_be64(QCOW2_INCOMPAT_COMPRESSION);
3645 if (qcow2_opts->extended_l2) {
3646 header->incompatible_features |=
3647 cpu_to_be64(QCOW2_INCOMPAT_EXTL2);
3650 ret = blk_pwrite(blk, 0, header, cluster_size, 0);
3651 g_free(header);
3652 if (ret < 0) {
3653 error_setg_errno(errp, -ret, "Could not write qcow2 header");
3654 goto out;
3657 /* Write a refcount table with one refcount block */
3658 refcount_table = g_malloc0(2 * cluster_size);
3659 refcount_table[0] = cpu_to_be64(2 * cluster_size);
3660 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0);
3661 g_free(refcount_table);
3663 if (ret < 0) {
3664 error_setg_errno(errp, -ret, "Could not write refcount table");
3665 goto out;
3668 blk_unref(blk);
3669 blk = NULL;
3672 * And now open the image and make it consistent first (i.e. increase the
3673 * refcount of the cluster that is occupied by the header and the refcount
3674 * table)
3676 options = qdict_new();
3677 qdict_put_str(options, "driver", "qcow2");
3678 qdict_put_str(options, "file", bs->node_name);
3679 if (data_bs) {
3680 qdict_put_str(options, "data-file", data_bs->node_name);
3682 blk = blk_new_open(NULL, NULL, options,
3683 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH,
3684 errp);
3685 if (blk == NULL) {
3686 ret = -EIO;
3687 goto out;
3690 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size);
3691 if (ret < 0) {
3692 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 "
3693 "header and refcount table");
3694 goto out;
3696 } else if (ret != 0) {
3697 error_report("Huh, first cluster in empty image is already in use?");
3698 abort();
3701 /* Set the external data file if necessary */
3702 if (data_bs) {
3703 BDRVQcow2State *s = blk_bs(blk)->opaque;
3704 s->image_data_file = g_strdup(data_bs->filename);
3707 /* Create a full header (including things like feature table) */
3708 ret = qcow2_update_header(blk_bs(blk));
3709 if (ret < 0) {
3710 error_setg_errno(errp, -ret, "Could not update qcow2 header");
3711 goto out;
3714 /* Okay, now that we have a valid image, let's give it the right size */
3715 ret = blk_truncate(blk, qcow2_opts->size, false, qcow2_opts->preallocation,
3716 0, errp);
3717 if (ret < 0) {
3718 error_prepend(errp, "Could not resize image: ");
3719 goto out;
3722 /* Want a backing file? There you go. */
3723 if (qcow2_opts->has_backing_file) {
3724 const char *backing_format = NULL;
3726 if (qcow2_opts->has_backing_fmt) {
3727 backing_format = BlockdevDriver_str(qcow2_opts->backing_fmt);
3730 ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file,
3731 backing_format, false);
3732 if (ret < 0) {
3733 error_setg_errno(errp, -ret, "Could not assign backing file '%s' "
3734 "with format '%s'", qcow2_opts->backing_file,
3735 backing_format);
3736 goto out;
3740 /* Want encryption? There you go. */
3741 if (qcow2_opts->has_encrypt) {
3742 ret = qcow2_set_up_encryption(blk_bs(blk), qcow2_opts->encrypt, errp);
3743 if (ret < 0) {
3744 goto out;
3748 blk_unref(blk);
3749 blk = NULL;
3751 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning.
3752 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to
3753 * have to setup decryption context. We're not doing any I/O on the top
3754 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does
3755 * not have effect.
3757 options = qdict_new();
3758 qdict_put_str(options, "driver", "qcow2");
3759 qdict_put_str(options, "file", bs->node_name);
3760 if (data_bs) {
3761 qdict_put_str(options, "data-file", data_bs->node_name);
3763 blk = blk_new_open(NULL, NULL, options,
3764 BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO,
3765 errp);
3766 if (blk == NULL) {
3767 ret = -EIO;
3768 goto out;
3771 ret = 0;
3772 out:
3773 blk_unref(blk);
3774 bdrv_unref(bs);
3775 bdrv_unref(data_bs);
3776 return ret;
3779 static int coroutine_fn qcow2_co_create_opts(BlockDriver *drv,
3780 const char *filename,
3781 QemuOpts *opts,
3782 Error **errp)
3784 BlockdevCreateOptions *create_options = NULL;
3785 QDict *qdict;
3786 Visitor *v;
3787 BlockDriverState *bs = NULL;
3788 BlockDriverState *data_bs = NULL;
3789 const char *val;
3790 int ret;
3792 /* Only the keyval visitor supports the dotted syntax needed for
3793 * encryption, so go through a QDict before getting a QAPI type. Ignore
3794 * options meant for the protocol layer so that the visitor doesn't
3795 * complain. */
3796 qdict = qemu_opts_to_qdict_filtered(opts, NULL, bdrv_qcow2.create_opts,
3797 true);
3799 /* Handle encryption options */
3800 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
3801 if (val && !strcmp(val, "on")) {
3802 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
3803 } else if (val && !strcmp(val, "off")) {
3804 qdict_del(qdict, BLOCK_OPT_ENCRYPT);
3807 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
3808 if (val && !strcmp(val, "aes")) {
3809 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
3812 /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into
3813 * version=v2/v3 below. */
3814 val = qdict_get_try_str(qdict, BLOCK_OPT_COMPAT_LEVEL);
3815 if (val && !strcmp(val, "0.10")) {
3816 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v2");
3817 } else if (val && !strcmp(val, "1.1")) {
3818 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3");
3821 /* Change legacy command line options into QMP ones */
3822 static const QDictRenames opt_renames[] = {
3823 { BLOCK_OPT_BACKING_FILE, "backing-file" },
3824 { BLOCK_OPT_BACKING_FMT, "backing-fmt" },
3825 { BLOCK_OPT_CLUSTER_SIZE, "cluster-size" },
3826 { BLOCK_OPT_LAZY_REFCOUNTS, "lazy-refcounts" },
3827 { BLOCK_OPT_EXTL2, "extended-l2" },
3828 { BLOCK_OPT_REFCOUNT_BITS, "refcount-bits" },
3829 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
3830 { BLOCK_OPT_COMPAT_LEVEL, "version" },
3831 { BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" },
3832 { BLOCK_OPT_COMPRESSION_TYPE, "compression-type" },
3833 { NULL, NULL },
3836 if (!qdict_rename_keys(qdict, opt_renames, errp)) {
3837 ret = -EINVAL;
3838 goto finish;
3841 /* Create and open the file (protocol layer) */
3842 ret = bdrv_create_file(filename, opts, errp);
3843 if (ret < 0) {
3844 goto finish;
3847 bs = bdrv_open(filename, NULL, NULL,
3848 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
3849 if (bs == NULL) {
3850 ret = -EIO;
3851 goto finish;
3854 /* Create and open an external data file (protocol layer) */
3855 val = qdict_get_try_str(qdict, BLOCK_OPT_DATA_FILE);
3856 if (val) {
3857 ret = bdrv_create_file(val, opts, errp);
3858 if (ret < 0) {
3859 goto finish;
3862 data_bs = bdrv_open(val, NULL, NULL,
3863 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL,
3864 errp);
3865 if (data_bs == NULL) {
3866 ret = -EIO;
3867 goto finish;
3870 qdict_del(qdict, BLOCK_OPT_DATA_FILE);
3871 qdict_put_str(qdict, "data-file", data_bs->node_name);
3874 /* Set 'driver' and 'node' options */
3875 qdict_put_str(qdict, "driver", "qcow2");
3876 qdict_put_str(qdict, "file", bs->node_name);
3878 /* Now get the QAPI type BlockdevCreateOptions */
3879 v = qobject_input_visitor_new_flat_confused(qdict, errp);
3880 if (!v) {
3881 ret = -EINVAL;
3882 goto finish;
3885 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
3886 visit_free(v);
3887 if (!create_options) {
3888 ret = -EINVAL;
3889 goto finish;
3892 /* Silently round up size */
3893 create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size,
3894 BDRV_SECTOR_SIZE);
3896 /* Create the qcow2 image (format layer) */
3897 ret = qcow2_co_create(create_options, errp);
3898 finish:
3899 if (ret < 0) {
3900 bdrv_co_delete_file_noerr(bs);
3901 bdrv_co_delete_file_noerr(data_bs);
3902 } else {
3903 ret = 0;
3906 qobject_unref(qdict);
3907 bdrv_unref(bs);
3908 bdrv_unref(data_bs);
3909 qapi_free_BlockdevCreateOptions(create_options);
3910 return ret;
3914 static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)
3916 int64_t nr;
3917 int res;
3919 /* Clamp to image length, before checking status of underlying sectors */
3920 if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) {
3921 bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset;
3924 if (!bytes) {
3925 return true;
3929 * bdrv_block_status_above doesn't merge different types of zeros, for
3930 * example, zeros which come from the region which is unallocated in
3931 * the whole backing chain, and zeros which come because of a short
3932 * backing file. So, we need a loop.
3934 do {
3935 res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL);
3936 offset += nr;
3937 bytes -= nr;
3938 } while (res >= 0 && (res & BDRV_BLOCK_ZERO) && nr && bytes);
3940 return res >= 0 && (res & BDRV_BLOCK_ZERO) && bytes == 0;
3943 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
3944 int64_t offset, int64_t bytes, BdrvRequestFlags flags)
3946 int ret;
3947 BDRVQcow2State *s = bs->opaque;
3949 uint32_t head = offset_into_subcluster(s, offset);
3950 uint32_t tail = ROUND_UP(offset + bytes, s->subcluster_size) -
3951 (offset + bytes);
3953 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes);
3954 if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) {
3955 tail = 0;
3958 if (head || tail) {
3959 uint64_t off;
3960 unsigned int nr;
3961 QCow2SubclusterType type;
3963 assert(head + bytes + tail <= s->subcluster_size);
3965 /* check whether remainder of cluster already reads as zero */
3966 if (!(is_zero(bs, offset - head, head) &&
3967 is_zero(bs, offset + bytes, tail))) {
3968 return -ENOTSUP;
3971 qemu_co_mutex_lock(&s->lock);
3972 /* We can have new write after previous check */
3973 offset -= head;
3974 bytes = s->subcluster_size;
3975 nr = s->subcluster_size;
3976 ret = qcow2_get_host_offset(bs, offset, &nr, &off, &type);
3977 if (ret < 0 ||
3978 (type != QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN &&
3979 type != QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC &&
3980 type != QCOW2_SUBCLUSTER_ZERO_PLAIN &&
3981 type != QCOW2_SUBCLUSTER_ZERO_ALLOC)) {
3982 qemu_co_mutex_unlock(&s->lock);
3983 return ret < 0 ? ret : -ENOTSUP;
3985 } else {
3986 qemu_co_mutex_lock(&s->lock);
3989 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes);
3991 /* Whatever is left can use real zero subclusters */
3992 ret = qcow2_subcluster_zeroize(bs, offset, bytes, flags);
3993 qemu_co_mutex_unlock(&s->lock);
3995 return ret;
3998 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs,
3999 int64_t offset, int64_t bytes)
4001 int ret;
4002 BDRVQcow2State *s = bs->opaque;
4004 /* If the image does not support QCOW_OFLAG_ZERO then discarding
4005 * clusters could expose stale data from the backing file. */
4006 if (s->qcow_version < 3 && bs->backing) {
4007 return -ENOTSUP;
4010 if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) {
4011 assert(bytes < s->cluster_size);
4012 /* Ignore partial clusters, except for the special case of the
4013 * complete partial cluster at the end of an unaligned file */
4014 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) ||
4015 offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) {
4016 return -ENOTSUP;
4020 qemu_co_mutex_lock(&s->lock);
4021 ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST,
4022 false);
4023 qemu_co_mutex_unlock(&s->lock);
4024 return ret;
4027 static int coroutine_fn
4028 qcow2_co_copy_range_from(BlockDriverState *bs,
4029 BdrvChild *src, int64_t src_offset,
4030 BdrvChild *dst, int64_t dst_offset,
4031 int64_t bytes, BdrvRequestFlags read_flags,
4032 BdrvRequestFlags write_flags)
4034 BDRVQcow2State *s = bs->opaque;
4035 int ret;
4036 unsigned int cur_bytes; /* number of bytes in current iteration */
4037 BdrvChild *child = NULL;
4038 BdrvRequestFlags cur_write_flags;
4040 assert(!bs->encrypted);
4041 qemu_co_mutex_lock(&s->lock);
4043 while (bytes != 0) {
4044 uint64_t copy_offset = 0;
4045 QCow2SubclusterType type;
4046 /* prepare next request */
4047 cur_bytes = MIN(bytes, INT_MAX);
4048 cur_write_flags = write_flags;
4050 ret = qcow2_get_host_offset(bs, src_offset, &cur_bytes,
4051 &copy_offset, &type);
4052 if (ret < 0) {
4053 goto out;
4056 switch (type) {
4057 case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN:
4058 case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC:
4059 if (bs->backing && bs->backing->bs) {
4060 int64_t backing_length = bdrv_getlength(bs->backing->bs);
4061 if (src_offset >= backing_length) {
4062 cur_write_flags |= BDRV_REQ_ZERO_WRITE;
4063 } else {
4064 child = bs->backing;
4065 cur_bytes = MIN(cur_bytes, backing_length - src_offset);
4066 copy_offset = src_offset;
4068 } else {
4069 cur_write_flags |= BDRV_REQ_ZERO_WRITE;
4071 break;
4073 case QCOW2_SUBCLUSTER_ZERO_PLAIN:
4074 case QCOW2_SUBCLUSTER_ZERO_ALLOC:
4075 cur_write_flags |= BDRV_REQ_ZERO_WRITE;
4076 break;
4078 case QCOW2_SUBCLUSTER_COMPRESSED:
4079 ret = -ENOTSUP;
4080 goto out;
4082 case QCOW2_SUBCLUSTER_NORMAL:
4083 child = s->data_file;
4084 break;
4086 default:
4087 abort();
4089 qemu_co_mutex_unlock(&s->lock);
4090 ret = bdrv_co_copy_range_from(child,
4091 copy_offset,
4092 dst, dst_offset,
4093 cur_bytes, read_flags, cur_write_flags);
4094 qemu_co_mutex_lock(&s->lock);
4095 if (ret < 0) {
4096 goto out;
4099 bytes -= cur_bytes;
4100 src_offset += cur_bytes;
4101 dst_offset += cur_bytes;
4103 ret = 0;
4105 out:
4106 qemu_co_mutex_unlock(&s->lock);
4107 return ret;
4110 static int coroutine_fn
4111 qcow2_co_copy_range_to(BlockDriverState *bs,
4112 BdrvChild *src, int64_t src_offset,
4113 BdrvChild *dst, int64_t dst_offset,
4114 int64_t bytes, BdrvRequestFlags read_flags,
4115 BdrvRequestFlags write_flags)
4117 BDRVQcow2State *s = bs->opaque;
4118 int ret;
4119 unsigned int cur_bytes; /* number of sectors in current iteration */
4120 uint64_t host_offset;
4121 QCowL2Meta *l2meta = NULL;
4123 assert(!bs->encrypted);
4125 qemu_co_mutex_lock(&s->lock);
4127 while (bytes != 0) {
4129 l2meta = NULL;
4131 cur_bytes = MIN(bytes, INT_MAX);
4133 /* TODO:
4134 * If src->bs == dst->bs, we could simply copy by incrementing
4135 * the refcnt, without copying user data.
4136 * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */
4137 ret = qcow2_alloc_host_offset(bs, dst_offset, &cur_bytes,
4138 &host_offset, &l2meta);
4139 if (ret < 0) {
4140 goto fail;
4143 ret = qcow2_pre_write_overlap_check(bs, 0, host_offset, cur_bytes,
4144 true);
4145 if (ret < 0) {
4146 goto fail;
4149 qemu_co_mutex_unlock(&s->lock);
4150 ret = bdrv_co_copy_range_to(src, src_offset, s->data_file, host_offset,
4151 cur_bytes, read_flags, write_flags);
4152 qemu_co_mutex_lock(&s->lock);
4153 if (ret < 0) {
4154 goto fail;
4157 ret = qcow2_handle_l2meta(bs, &l2meta, true);
4158 if (ret) {
4159 goto fail;
4162 bytes -= cur_bytes;
4163 src_offset += cur_bytes;
4164 dst_offset += cur_bytes;
4166 ret = 0;
4168 fail:
4169 qcow2_handle_l2meta(bs, &l2meta, false);
4171 qemu_co_mutex_unlock(&s->lock);
4173 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
4175 return ret;
4178 static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset,
4179 bool exact, PreallocMode prealloc,
4180 BdrvRequestFlags flags, Error **errp)
4182 BDRVQcow2State *s = bs->opaque;
4183 uint64_t old_length;
4184 int64_t new_l1_size;
4185 int ret;
4186 QDict *options;
4188 if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA &&
4189 prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL)
4191 error_setg(errp, "Unsupported preallocation mode '%s'",
4192 PreallocMode_str(prealloc));
4193 return -ENOTSUP;
4196 if (!QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)) {
4197 error_setg(errp, "The new size must be a multiple of %u",
4198 (unsigned) BDRV_SECTOR_SIZE);
4199 return -EINVAL;
4202 qemu_co_mutex_lock(&s->lock);
4205 * Even though we store snapshot size for all images, it was not
4206 * required until v3, so it is not safe to proceed for v2.
4208 if (s->nb_snapshots && s->qcow_version < 3) {
4209 error_setg(errp, "Can't resize a v2 image which has snapshots");
4210 ret = -ENOTSUP;
4211 goto fail;
4214 /* See qcow2-bitmap.c for which bitmap scenarios prevent a resize. */
4215 if (qcow2_truncate_bitmaps_check(bs, errp)) {
4216 ret = -ENOTSUP;
4217 goto fail;
4220 old_length = bs->total_sectors * BDRV_SECTOR_SIZE;
4221 new_l1_size = size_to_l1(s, offset);
4223 if (offset < old_length) {
4224 int64_t last_cluster, old_file_size;
4225 if (prealloc != PREALLOC_MODE_OFF) {
4226 error_setg(errp,
4227 "Preallocation can't be used for shrinking an image");
4228 ret = -EINVAL;
4229 goto fail;
4232 ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size),
4233 old_length - ROUND_UP(offset,
4234 s->cluster_size),
4235 QCOW2_DISCARD_ALWAYS, true);
4236 if (ret < 0) {
4237 error_setg_errno(errp, -ret, "Failed to discard cropped clusters");
4238 goto fail;
4241 ret = qcow2_shrink_l1_table(bs, new_l1_size);
4242 if (ret < 0) {
4243 error_setg_errno(errp, -ret,
4244 "Failed to reduce the number of L2 tables");
4245 goto fail;
4248 ret = qcow2_shrink_reftable(bs);
4249 if (ret < 0) {
4250 error_setg_errno(errp, -ret,
4251 "Failed to discard unused refblocks");
4252 goto fail;
4255 old_file_size = bdrv_getlength(bs->file->bs);
4256 if (old_file_size < 0) {
4257 error_setg_errno(errp, -old_file_size,
4258 "Failed to inquire current file length");
4259 ret = old_file_size;
4260 goto fail;
4262 last_cluster = qcow2_get_last_cluster(bs, old_file_size);
4263 if (last_cluster < 0) {
4264 error_setg_errno(errp, -last_cluster,
4265 "Failed to find the last cluster");
4266 ret = last_cluster;
4267 goto fail;
4269 if ((last_cluster + 1) * s->cluster_size < old_file_size) {
4270 Error *local_err = NULL;
4273 * Do not pass @exact here: It will not help the user if
4274 * we get an error here just because they wanted to shrink
4275 * their qcow2 image (on a block device) with qemu-img.
4276 * (And on the qcow2 layer, the @exact requirement is
4277 * always fulfilled, so there is no need to pass it on.)
4279 bdrv_co_truncate(bs->file, (last_cluster + 1) * s->cluster_size,
4280 false, PREALLOC_MODE_OFF, 0, &local_err);
4281 if (local_err) {
4282 warn_reportf_err(local_err,
4283 "Failed to truncate the tail of the image: ");
4286 } else {
4287 ret = qcow2_grow_l1_table(bs, new_l1_size, true);
4288 if (ret < 0) {
4289 error_setg_errno(errp, -ret, "Failed to grow the L1 table");
4290 goto fail;
4293 if (data_file_is_raw(bs) && prealloc == PREALLOC_MODE_OFF) {
4295 * When creating a qcow2 image with data-file-raw, we enforce
4296 * at least prealloc=metadata, so that the L1/L2 tables are
4297 * fully allocated and reading from the data file will return
4298 * the same data as reading from the qcow2 image. When the
4299 * image is grown, we must consequently preallocate the
4300 * metadata structures to cover the added area.
4302 prealloc = PREALLOC_MODE_METADATA;
4306 switch (prealloc) {
4307 case PREALLOC_MODE_OFF:
4308 if (has_data_file(bs)) {
4310 * If the caller wants an exact resize, the external data
4311 * file should be resized to the exact target size, too,
4312 * so we pass @exact here.
4314 ret = bdrv_co_truncate(s->data_file, offset, exact, prealloc, 0,
4315 errp);
4316 if (ret < 0) {
4317 goto fail;
4320 break;
4322 case PREALLOC_MODE_METADATA:
4323 ret = preallocate_co(bs, old_length, offset, prealloc, errp);
4324 if (ret < 0) {
4325 goto fail;
4327 break;
4329 case PREALLOC_MODE_FALLOC:
4330 case PREALLOC_MODE_FULL:
4332 int64_t allocation_start, host_offset, guest_offset;
4333 int64_t clusters_allocated;
4334 int64_t old_file_size, last_cluster, new_file_size;
4335 uint64_t nb_new_data_clusters, nb_new_l2_tables;
4336 bool subclusters_need_allocation = false;
4338 /* With a data file, preallocation means just allocating the metadata
4339 * and forwarding the truncate request to the data file */
4340 if (has_data_file(bs)) {
4341 ret = preallocate_co(bs, old_length, offset, prealloc, errp);
4342 if (ret < 0) {
4343 goto fail;
4345 break;
4348 old_file_size = bdrv_getlength(bs->file->bs);
4349 if (old_file_size < 0) {
4350 error_setg_errno(errp, -old_file_size,
4351 "Failed to inquire current file length");
4352 ret = old_file_size;
4353 goto fail;
4356 last_cluster = qcow2_get_last_cluster(bs, old_file_size);
4357 if (last_cluster >= 0) {
4358 old_file_size = (last_cluster + 1) * s->cluster_size;
4359 } else {
4360 old_file_size = ROUND_UP(old_file_size, s->cluster_size);
4363 nb_new_data_clusters = (ROUND_UP(offset, s->cluster_size) -
4364 start_of_cluster(s, old_length)) >> s->cluster_bits;
4366 /* This is an overestimation; we will not actually allocate space for
4367 * these in the file but just make sure the new refcount structures are
4368 * able to cover them so we will not have to allocate new refblocks
4369 * while entering the data blocks in the potentially new L2 tables.
4370 * (We do not actually care where the L2 tables are placed. Maybe they
4371 * are already allocated or they can be placed somewhere before
4372 * @old_file_size. It does not matter because they will be fully
4373 * allocated automatically, so they do not need to be covered by the
4374 * preallocation. All that matters is that we will not have to allocate
4375 * new refcount structures for them.) */
4376 nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters,
4377 s->cluster_size / l2_entry_size(s));
4378 /* The cluster range may not be aligned to L2 boundaries, so add one L2
4379 * table for a potential head/tail */
4380 nb_new_l2_tables++;
4382 allocation_start = qcow2_refcount_area(bs, old_file_size,
4383 nb_new_data_clusters +
4384 nb_new_l2_tables,
4385 true, 0, 0);
4386 if (allocation_start < 0) {
4387 error_setg_errno(errp, -allocation_start,
4388 "Failed to resize refcount structures");
4389 ret = allocation_start;
4390 goto fail;
4393 clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start,
4394 nb_new_data_clusters);
4395 if (clusters_allocated < 0) {
4396 error_setg_errno(errp, -clusters_allocated,
4397 "Failed to allocate data clusters");
4398 ret = clusters_allocated;
4399 goto fail;
4402 assert(clusters_allocated == nb_new_data_clusters);
4404 /* Allocate the data area */
4405 new_file_size = allocation_start +
4406 nb_new_data_clusters * s->cluster_size;
4408 * Image file grows, so @exact does not matter.
4410 * If we need to zero out the new area, try first whether the protocol
4411 * driver can already take care of this.
4413 if (flags & BDRV_REQ_ZERO_WRITE) {
4414 ret = bdrv_co_truncate(bs->file, new_file_size, false, prealloc,
4415 BDRV_REQ_ZERO_WRITE, NULL);
4416 if (ret >= 0) {
4417 flags &= ~BDRV_REQ_ZERO_WRITE;
4418 /* Ensure that we read zeroes and not backing file data */
4419 subclusters_need_allocation = true;
4421 } else {
4422 ret = -1;
4424 if (ret < 0) {
4425 ret = bdrv_co_truncate(bs->file, new_file_size, false, prealloc, 0,
4426 errp);
4428 if (ret < 0) {
4429 error_prepend(errp, "Failed to resize underlying file: ");
4430 qcow2_free_clusters(bs, allocation_start,
4431 nb_new_data_clusters * s->cluster_size,
4432 QCOW2_DISCARD_OTHER);
4433 goto fail;
4436 /* Create the necessary L2 entries */
4437 host_offset = allocation_start;
4438 guest_offset = old_length;
4439 while (nb_new_data_clusters) {
4440 int64_t nb_clusters = MIN(
4441 nb_new_data_clusters,
4442 s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset));
4443 unsigned cow_start_length = offset_into_cluster(s, guest_offset);
4444 QCowL2Meta allocation;
4445 guest_offset = start_of_cluster(s, guest_offset);
4446 allocation = (QCowL2Meta) {
4447 .offset = guest_offset,
4448 .alloc_offset = host_offset,
4449 .nb_clusters = nb_clusters,
4450 .cow_start = {
4451 .offset = 0,
4452 .nb_bytes = cow_start_length,
4454 .cow_end = {
4455 .offset = nb_clusters << s->cluster_bits,
4456 .nb_bytes = 0,
4458 .prealloc = !subclusters_need_allocation,
4460 qemu_co_queue_init(&allocation.dependent_requests);
4462 ret = qcow2_alloc_cluster_link_l2(bs, &allocation);
4463 if (ret < 0) {
4464 error_setg_errno(errp, -ret, "Failed to update L2 tables");
4465 qcow2_free_clusters(bs, host_offset,
4466 nb_new_data_clusters * s->cluster_size,
4467 QCOW2_DISCARD_OTHER);
4468 goto fail;
4471 guest_offset += nb_clusters * s->cluster_size;
4472 host_offset += nb_clusters * s->cluster_size;
4473 nb_new_data_clusters -= nb_clusters;
4475 break;
4478 default:
4479 g_assert_not_reached();
4482 if ((flags & BDRV_REQ_ZERO_WRITE) && offset > old_length) {
4483 uint64_t zero_start = QEMU_ALIGN_UP(old_length, s->subcluster_size);
4486 * Use zero clusters as much as we can. qcow2_subcluster_zeroize()
4487 * requires a subcluster-aligned start. The end may be unaligned if
4488 * it is at the end of the image (which it is here).
4490 if (offset > zero_start) {
4491 ret = qcow2_subcluster_zeroize(bs, zero_start, offset - zero_start,
4493 if (ret < 0) {
4494 error_setg_errno(errp, -ret, "Failed to zero out new clusters");
4495 goto fail;
4499 /* Write explicit zeros for the unaligned head */
4500 if (zero_start > old_length) {
4501 uint64_t len = MIN(zero_start, offset) - old_length;
4502 uint8_t *buf = qemu_blockalign0(bs, len);
4503 QEMUIOVector qiov;
4504 qemu_iovec_init_buf(&qiov, buf, len);
4506 qemu_co_mutex_unlock(&s->lock);
4507 ret = qcow2_co_pwritev_part(bs, old_length, len, &qiov, 0, 0);
4508 qemu_co_mutex_lock(&s->lock);
4510 qemu_vfree(buf);
4511 if (ret < 0) {
4512 error_setg_errno(errp, -ret, "Failed to zero out the new area");
4513 goto fail;
4518 if (prealloc != PREALLOC_MODE_OFF) {
4519 /* Flush metadata before actually changing the image size */
4520 ret = qcow2_write_caches(bs);
4521 if (ret < 0) {
4522 error_setg_errno(errp, -ret,
4523 "Failed to flush the preallocated area to disk");
4524 goto fail;
4528 bs->total_sectors = offset / BDRV_SECTOR_SIZE;
4530 /* write updated header.size */
4531 offset = cpu_to_be64(offset);
4532 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
4533 &offset, sizeof(offset));
4534 if (ret < 0) {
4535 error_setg_errno(errp, -ret, "Failed to update the image size");
4536 goto fail;
4539 s->l1_vm_state_index = new_l1_size;
4541 /* Update cache sizes */
4542 options = qdict_clone_shallow(bs->options);
4543 ret = qcow2_update_options(bs, options, s->flags, errp);
4544 qobject_unref(options);
4545 if (ret < 0) {
4546 goto fail;
4548 ret = 0;
4549 fail:
4550 qemu_co_mutex_unlock(&s->lock);
4551 return ret;
4554 static coroutine_fn int
4555 qcow2_co_pwritev_compressed_task(BlockDriverState *bs,
4556 uint64_t offset, uint64_t bytes,
4557 QEMUIOVector *qiov, size_t qiov_offset)
4559 BDRVQcow2State *s = bs->opaque;
4560 int ret;
4561 ssize_t out_len;
4562 uint8_t *buf, *out_buf;
4563 uint64_t cluster_offset;
4565 assert(bytes == s->cluster_size || (bytes < s->cluster_size &&
4566 (offset + bytes == bs->total_sectors << BDRV_SECTOR_BITS)));
4568 buf = qemu_blockalign(bs, s->cluster_size);
4569 if (bytes < s->cluster_size) {
4570 /* Zero-pad last write if image size is not cluster aligned */
4571 memset(buf + bytes, 0, s->cluster_size - bytes);
4573 qemu_iovec_to_buf(qiov, qiov_offset, buf, bytes);
4575 out_buf = g_malloc(s->cluster_size);
4577 out_len = qcow2_co_compress(bs, out_buf, s->cluster_size - 1,
4578 buf, s->cluster_size);
4579 if (out_len == -ENOMEM) {
4580 /* could not compress: write normal cluster */
4581 ret = qcow2_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset, 0);
4582 if (ret < 0) {
4583 goto fail;
4585 goto success;
4586 } else if (out_len < 0) {
4587 ret = -EINVAL;
4588 goto fail;
4591 qemu_co_mutex_lock(&s->lock);
4592 ret = qcow2_alloc_compressed_cluster_offset(bs, offset, out_len,
4593 &cluster_offset);
4594 if (ret < 0) {
4595 qemu_co_mutex_unlock(&s->lock);
4596 goto fail;
4599 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len, true);
4600 qemu_co_mutex_unlock(&s->lock);
4601 if (ret < 0) {
4602 goto fail;
4605 BLKDBG_EVENT(s->data_file, BLKDBG_WRITE_COMPRESSED);
4606 ret = bdrv_co_pwrite(s->data_file, cluster_offset, out_len, out_buf, 0);
4607 if (ret < 0) {
4608 goto fail;
4610 success:
4611 ret = 0;
4612 fail:
4613 qemu_vfree(buf);
4614 g_free(out_buf);
4615 return ret;
4618 static coroutine_fn int qcow2_co_pwritev_compressed_task_entry(AioTask *task)
4620 Qcow2AioTask *t = container_of(task, Qcow2AioTask, task);
4622 assert(!t->subcluster_type && !t->l2meta);
4624 return qcow2_co_pwritev_compressed_task(t->bs, t->offset, t->bytes, t->qiov,
4625 t->qiov_offset);
4629 * XXX: put compressed sectors first, then all the cluster aligned
4630 * tables to avoid losing bytes in alignment
4632 static coroutine_fn int
4633 qcow2_co_pwritev_compressed_part(BlockDriverState *bs,
4634 int64_t offset, int64_t bytes,
4635 QEMUIOVector *qiov, size_t qiov_offset)
4637 BDRVQcow2State *s = bs->opaque;
4638 AioTaskPool *aio = NULL;
4639 int ret = 0;
4641 if (has_data_file(bs)) {
4642 return -ENOTSUP;
4645 if (bytes == 0) {
4647 * align end of file to a sector boundary to ease reading with
4648 * sector based I/Os
4650 int64_t len = bdrv_getlength(bs->file->bs);
4651 if (len < 0) {
4652 return len;
4654 return bdrv_co_truncate(bs->file, len, false, PREALLOC_MODE_OFF, 0,
4655 NULL);
4658 if (offset_into_cluster(s, offset)) {
4659 return -EINVAL;
4662 if (offset_into_cluster(s, bytes) &&
4663 (offset + bytes) != (bs->total_sectors << BDRV_SECTOR_BITS)) {
4664 return -EINVAL;
4667 while (bytes && aio_task_pool_status(aio) == 0) {
4668 uint64_t chunk_size = MIN(bytes, s->cluster_size);
4670 if (!aio && chunk_size != bytes) {
4671 aio = aio_task_pool_new(QCOW2_MAX_WORKERS);
4674 ret = qcow2_add_task(bs, aio, qcow2_co_pwritev_compressed_task_entry,
4675 0, 0, offset, chunk_size, qiov, qiov_offset, NULL);
4676 if (ret < 0) {
4677 break;
4679 qiov_offset += chunk_size;
4680 offset += chunk_size;
4681 bytes -= chunk_size;
4684 if (aio) {
4685 aio_task_pool_wait_all(aio);
4686 if (ret == 0) {
4687 ret = aio_task_pool_status(aio);
4689 g_free(aio);
4692 return ret;
4695 static int coroutine_fn
4696 qcow2_co_preadv_compressed(BlockDriverState *bs,
4697 uint64_t l2_entry,
4698 uint64_t offset,
4699 uint64_t bytes,
4700 QEMUIOVector *qiov,
4701 size_t qiov_offset)
4703 BDRVQcow2State *s = bs->opaque;
4704 int ret = 0, csize;
4705 uint64_t coffset;
4706 uint8_t *buf, *out_buf;
4707 int offset_in_cluster = offset_into_cluster(s, offset);
4709 qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize);
4711 buf = g_try_malloc(csize);
4712 if (!buf) {
4713 return -ENOMEM;
4716 out_buf = qemu_blockalign(bs, s->cluster_size);
4718 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
4719 ret = bdrv_co_pread(bs->file, coffset, csize, buf, 0);
4720 if (ret < 0) {
4721 goto fail;
4724 if (qcow2_co_decompress(bs, out_buf, s->cluster_size, buf, csize) < 0) {
4725 ret = -EIO;
4726 goto fail;
4729 qemu_iovec_from_buf(qiov, qiov_offset, out_buf + offset_in_cluster, bytes);
4731 fail:
4732 qemu_vfree(out_buf);
4733 g_free(buf);
4735 return ret;
4738 static int make_completely_empty(BlockDriverState *bs)
4740 BDRVQcow2State *s = bs->opaque;
4741 Error *local_err = NULL;
4742 int ret, l1_clusters;
4743 int64_t offset;
4744 uint64_t *new_reftable = NULL;
4745 uint64_t rt_entry, l1_size2;
4746 struct {
4747 uint64_t l1_offset;
4748 uint64_t reftable_offset;
4749 uint32_t reftable_clusters;
4750 } QEMU_PACKED l1_ofs_rt_ofs_cls;
4752 ret = qcow2_cache_empty(bs, s->l2_table_cache);
4753 if (ret < 0) {
4754 goto fail;
4757 ret = qcow2_cache_empty(bs, s->refcount_block_cache);
4758 if (ret < 0) {
4759 goto fail;
4762 /* Refcounts will be broken utterly */
4763 ret = qcow2_mark_dirty(bs);
4764 if (ret < 0) {
4765 goto fail;
4768 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
4770 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / L1E_SIZE);
4771 l1_size2 = (uint64_t)s->l1_size * L1E_SIZE;
4773 /* After this call, neither the in-memory nor the on-disk refcount
4774 * information accurately describe the actual references */
4776 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset,
4777 l1_clusters * s->cluster_size, 0);
4778 if (ret < 0) {
4779 goto fail_broken_refcounts;
4781 memset(s->l1_table, 0, l1_size2);
4783 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE);
4785 /* Overwrite enough clusters at the beginning of the sectors to place
4786 * the refcount table, a refcount block and the L1 table in; this may
4787 * overwrite parts of the existing refcount and L1 table, which is not
4788 * an issue because the dirty flag is set, complete data loss is in fact
4789 * desired and partial data loss is consequently fine as well */
4790 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size,
4791 (2 + l1_clusters) * s->cluster_size, 0);
4792 /* This call (even if it failed overall) may have overwritten on-disk
4793 * refcount structures; in that case, the in-memory refcount information
4794 * will probably differ from the on-disk information which makes the BDS
4795 * unusable */
4796 if (ret < 0) {
4797 goto fail_broken_refcounts;
4800 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
4801 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE);
4803 /* "Create" an empty reftable (one cluster) directly after the image
4804 * header and an empty L1 table three clusters after the image header;
4805 * the cluster between those two will be used as the first refblock */
4806 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size);
4807 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size);
4808 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1);
4809 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset),
4810 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls));
4811 if (ret < 0) {
4812 goto fail_broken_refcounts;
4815 s->l1_table_offset = 3 * s->cluster_size;
4817 new_reftable = g_try_new0(uint64_t, s->cluster_size / REFTABLE_ENTRY_SIZE);
4818 if (!new_reftable) {
4819 ret = -ENOMEM;
4820 goto fail_broken_refcounts;
4823 s->refcount_table_offset = s->cluster_size;
4824 s->refcount_table_size = s->cluster_size / REFTABLE_ENTRY_SIZE;
4825 s->max_refcount_table_index = 0;
4827 g_free(s->refcount_table);
4828 s->refcount_table = new_reftable;
4829 new_reftable = NULL;
4831 /* Now the in-memory refcount information again corresponds to the on-disk
4832 * information (reftable is empty and no refblocks (the refblock cache is
4833 * empty)); however, this means some clusters (e.g. the image header) are
4834 * referenced, but not refcounted, but the normal qcow2 code assumes that
4835 * the in-memory information is always correct */
4837 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
4839 /* Enter the first refblock into the reftable */
4840 rt_entry = cpu_to_be64(2 * s->cluster_size);
4841 ret = bdrv_pwrite_sync(bs->file, s->cluster_size,
4842 &rt_entry, sizeof(rt_entry));
4843 if (ret < 0) {
4844 goto fail_broken_refcounts;
4846 s->refcount_table[0] = 2 * s->cluster_size;
4848 s->free_cluster_index = 0;
4849 assert(3 + l1_clusters <= s->refcount_block_size);
4850 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2);
4851 if (offset < 0) {
4852 ret = offset;
4853 goto fail_broken_refcounts;
4854 } else if (offset > 0) {
4855 error_report("First cluster in emptied image is in use");
4856 abort();
4859 /* Now finally the in-memory information corresponds to the on-disk
4860 * structures and is correct */
4861 ret = qcow2_mark_clean(bs);
4862 if (ret < 0) {
4863 goto fail;
4866 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, false,
4867 PREALLOC_MODE_OFF, 0, &local_err);
4868 if (ret < 0) {
4869 error_report_err(local_err);
4870 goto fail;
4873 return 0;
4875 fail_broken_refcounts:
4876 /* The BDS is unusable at this point. If we wanted to make it usable, we
4877 * would have to call qcow2_refcount_close(), qcow2_refcount_init(),
4878 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
4879 * again. However, because the functions which could have caused this error
4880 * path to be taken are used by those functions as well, it's very likely
4881 * that that sequence will fail as well. Therefore, just eject the BDS. */
4882 bs->drv = NULL;
4884 fail:
4885 g_free(new_reftable);
4886 return ret;
4889 static int qcow2_make_empty(BlockDriverState *bs)
4891 BDRVQcow2State *s = bs->opaque;
4892 uint64_t offset, end_offset;
4893 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size);
4894 int l1_clusters, ret = 0;
4896 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / L1E_SIZE);
4898 if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps &&
4899 3 + l1_clusters <= s->refcount_block_size &&
4900 s->crypt_method_header != QCOW_CRYPT_LUKS &&
4901 !has_data_file(bs)) {
4902 /* The following function only works for qcow2 v3 images (it
4903 * requires the dirty flag) and only as long as there are no
4904 * features that reserve extra clusters (such as snapshots,
4905 * LUKS header, or persistent bitmaps), because it completely
4906 * empties the image. Furthermore, the L1 table and three
4907 * additional clusters (image header, refcount table, one
4908 * refcount block) have to fit inside one refcount block. It
4909 * only resets the image file, i.e. does not work with an
4910 * external data file. */
4911 return make_completely_empty(bs);
4914 /* This fallback code simply discards every active cluster; this is slow,
4915 * but works in all cases */
4916 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE;
4917 for (offset = 0; offset < end_offset; offset += step) {
4918 /* As this function is generally used after committing an external
4919 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
4920 * default action for this kind of discard is to pass the discard,
4921 * which will ideally result in an actually smaller image file, as
4922 * is probably desired. */
4923 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset),
4924 QCOW2_DISCARD_SNAPSHOT, true);
4925 if (ret < 0) {
4926 break;
4930 return ret;
4933 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs)
4935 BDRVQcow2State *s = bs->opaque;
4936 int ret;
4938 qemu_co_mutex_lock(&s->lock);
4939 ret = qcow2_write_caches(bs);
4940 qemu_co_mutex_unlock(&s->lock);
4942 return ret;
4945 static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
4946 Error **errp)
4948 Error *local_err = NULL;
4949 BlockMeasureInfo *info;
4950 uint64_t required = 0; /* bytes that contribute to required size */
4951 uint64_t virtual_size; /* disk size as seen by guest */
4952 uint64_t refcount_bits;
4953 uint64_t l2_tables;
4954 uint64_t luks_payload_size = 0;
4955 size_t cluster_size;
4956 int version;
4957 char *optstr;
4958 PreallocMode prealloc;
4959 bool has_backing_file;
4960 bool has_luks;
4961 bool extended_l2;
4962 size_t l2e_size;
4964 /* Parse image creation options */
4965 extended_l2 = qemu_opt_get_bool_del(opts, BLOCK_OPT_EXTL2, false);
4967 cluster_size = qcow2_opt_get_cluster_size_del(opts, extended_l2,
4968 &local_err);
4969 if (local_err) {
4970 goto err;
4973 version = qcow2_opt_get_version_del(opts, &local_err);
4974 if (local_err) {
4975 goto err;
4978 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err);
4979 if (local_err) {
4980 goto err;
4983 optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
4984 prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr,
4985 PREALLOC_MODE_OFF, &local_err);
4986 g_free(optstr);
4987 if (local_err) {
4988 goto err;
4991 optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
4992 has_backing_file = !!optstr;
4993 g_free(optstr);
4995 optstr = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT);
4996 has_luks = optstr && strcmp(optstr, "luks") == 0;
4997 g_free(optstr);
4999 if (has_luks) {
5000 g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL;
5001 QDict *cryptoopts = qcow2_extract_crypto_opts(opts, "luks", errp);
5002 size_t headerlen;
5004 create_opts = block_crypto_create_opts_init(cryptoopts, errp);
5005 qobject_unref(cryptoopts);
5006 if (!create_opts) {
5007 goto err;
5010 if (!qcrypto_block_calculate_payload_offset(create_opts,
5011 "encrypt.",
5012 &headerlen,
5013 &local_err)) {
5014 goto err;
5017 luks_payload_size = ROUND_UP(headerlen, cluster_size);
5020 virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
5021 virtual_size = ROUND_UP(virtual_size, cluster_size);
5023 /* Check that virtual disk size is valid */
5024 l2e_size = extended_l2 ? L2E_SIZE_EXTENDED : L2E_SIZE_NORMAL;
5025 l2_tables = DIV_ROUND_UP(virtual_size / cluster_size,
5026 cluster_size / l2e_size);
5027 if (l2_tables * L1E_SIZE > QCOW_MAX_L1_SIZE) {
5028 error_setg(&local_err, "The image size is too large "
5029 "(try using a larger cluster size)");
5030 goto err;
5033 /* Account for input image */
5034 if (in_bs) {
5035 int64_t ssize = bdrv_getlength(in_bs);
5036 if (ssize < 0) {
5037 error_setg_errno(&local_err, -ssize,
5038 "Unable to get image virtual_size");
5039 goto err;
5042 virtual_size = ROUND_UP(ssize, cluster_size);
5044 if (has_backing_file) {
5045 /* We don't how much of the backing chain is shared by the input
5046 * image and the new image file. In the worst case the new image's
5047 * backing file has nothing in common with the input image. Be
5048 * conservative and assume all clusters need to be written.
5050 required = virtual_size;
5051 } else {
5052 int64_t offset;
5053 int64_t pnum = 0;
5055 for (offset = 0; offset < ssize; offset += pnum) {
5056 int ret;
5058 ret = bdrv_block_status_above(in_bs, NULL, offset,
5059 ssize - offset, &pnum, NULL,
5060 NULL);
5061 if (ret < 0) {
5062 error_setg_errno(&local_err, -ret,
5063 "Unable to get block status");
5064 goto err;
5067 if (ret & BDRV_BLOCK_ZERO) {
5068 /* Skip zero regions (safe with no backing file) */
5069 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) ==
5070 (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) {
5071 /* Extend pnum to end of cluster for next iteration */
5072 pnum = ROUND_UP(offset + pnum, cluster_size) - offset;
5074 /* Count clusters we've seen */
5075 required += offset % cluster_size + pnum;
5081 /* Take into account preallocation. Nothing special is needed for
5082 * PREALLOC_MODE_METADATA since metadata is always counted.
5084 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
5085 required = virtual_size;
5088 info = g_new0(BlockMeasureInfo, 1);
5089 info->fully_allocated = luks_payload_size +
5090 qcow2_calc_prealloc_size(virtual_size, cluster_size,
5091 ctz32(refcount_bits), extended_l2);
5094 * Remove data clusters that are not required. This overestimates the
5095 * required size because metadata needed for the fully allocated file is
5096 * still counted. Show bitmaps only if both source and destination
5097 * would support them.
5099 info->required = info->fully_allocated - virtual_size + required;
5100 info->has_bitmaps = version >= 3 && in_bs &&
5101 bdrv_supports_persistent_dirty_bitmap(in_bs);
5102 if (info->has_bitmaps) {
5103 info->bitmaps = qcow2_get_persistent_dirty_bitmap_size(in_bs,
5104 cluster_size);
5106 return info;
5108 err:
5109 error_propagate(errp, local_err);
5110 return NULL;
5113 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
5115 BDRVQcow2State *s = bs->opaque;
5116 bdi->cluster_size = s->cluster_size;
5117 bdi->vm_state_offset = qcow2_vm_state_offset(s);
5118 bdi->is_dirty = s->incompatible_features & QCOW2_INCOMPAT_DIRTY;
5119 return 0;
5122 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs,
5123 Error **errp)
5125 BDRVQcow2State *s = bs->opaque;
5126 ImageInfoSpecific *spec_info;
5127 QCryptoBlockInfo *encrypt_info = NULL;
5129 if (s->crypto != NULL) {
5130 encrypt_info = qcrypto_block_get_info(s->crypto, errp);
5131 if (!encrypt_info) {
5132 return NULL;
5136 spec_info = g_new(ImageInfoSpecific, 1);
5137 *spec_info = (ImageInfoSpecific){
5138 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2,
5139 .u.qcow2.data = g_new0(ImageInfoSpecificQCow2, 1),
5141 if (s->qcow_version == 2) {
5142 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
5143 .compat = g_strdup("0.10"),
5144 .refcount_bits = s->refcount_bits,
5146 } else if (s->qcow_version == 3) {
5147 Qcow2BitmapInfoList *bitmaps;
5148 if (!qcow2_get_bitmap_info_list(bs, &bitmaps, errp)) {
5149 qapi_free_ImageInfoSpecific(spec_info);
5150 qapi_free_QCryptoBlockInfo(encrypt_info);
5151 return NULL;
5153 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
5154 .compat = g_strdup("1.1"),
5155 .lazy_refcounts = s->compatible_features &
5156 QCOW2_COMPAT_LAZY_REFCOUNTS,
5157 .has_lazy_refcounts = true,
5158 .corrupt = s->incompatible_features &
5159 QCOW2_INCOMPAT_CORRUPT,
5160 .has_corrupt = true,
5161 .has_extended_l2 = true,
5162 .extended_l2 = has_subclusters(s),
5163 .refcount_bits = s->refcount_bits,
5164 .has_bitmaps = !!bitmaps,
5165 .bitmaps = bitmaps,
5166 .has_data_file = !!s->image_data_file,
5167 .data_file = g_strdup(s->image_data_file),
5168 .has_data_file_raw = has_data_file(bs),
5169 .data_file_raw = data_file_is_raw(bs),
5170 .compression_type = s->compression_type,
5172 } else {
5173 /* if this assertion fails, this probably means a new version was
5174 * added without having it covered here */
5175 assert(false);
5178 if (encrypt_info) {
5179 ImageInfoSpecificQCow2Encryption *qencrypt =
5180 g_new(ImageInfoSpecificQCow2Encryption, 1);
5181 switch (encrypt_info->format) {
5182 case Q_CRYPTO_BLOCK_FORMAT_QCOW:
5183 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES;
5184 break;
5185 case Q_CRYPTO_BLOCK_FORMAT_LUKS:
5186 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS;
5187 qencrypt->u.luks = encrypt_info->u.luks;
5188 break;
5189 default:
5190 abort();
5192 /* Since we did shallow copy above, erase any pointers
5193 * in the original info */
5194 memset(&encrypt_info->u, 0, sizeof(encrypt_info->u));
5195 qapi_free_QCryptoBlockInfo(encrypt_info);
5197 spec_info->u.qcow2.data->has_encrypt = true;
5198 spec_info->u.qcow2.data->encrypt = qencrypt;
5201 return spec_info;
5204 static int qcow2_has_zero_init(BlockDriverState *bs)
5206 BDRVQcow2State *s = bs->opaque;
5207 bool preallocated;
5209 if (qemu_in_coroutine()) {
5210 qemu_co_mutex_lock(&s->lock);
5213 * Check preallocation status: Preallocated images have all L2
5214 * tables allocated, nonpreallocated images have none. It is
5215 * therefore enough to check the first one.
5217 preallocated = s->l1_size > 0 && s->l1_table[0] != 0;
5218 if (qemu_in_coroutine()) {
5219 qemu_co_mutex_unlock(&s->lock);
5222 if (!preallocated) {
5223 return 1;
5224 } else if (bs->encrypted) {
5225 return 0;
5226 } else {
5227 return bdrv_has_zero_init(s->data_file->bs);
5232 * Check the request to vmstate. On success return
5233 * qcow2_vm_state_offset(bs) + @pos
5235 static int64_t qcow2_check_vmstate_request(BlockDriverState *bs,
5236 QEMUIOVector *qiov, int64_t pos)
5238 BDRVQcow2State *s = bs->opaque;
5239 int64_t vmstate_offset = qcow2_vm_state_offset(s);
5240 int ret;
5242 /* Incoming requests must be OK */
5243 bdrv_check_qiov_request(pos, qiov->size, qiov, 0, &error_abort);
5245 if (INT64_MAX - pos < vmstate_offset) {
5246 return -EIO;
5249 pos += vmstate_offset;
5250 ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL);
5251 if (ret < 0) {
5252 return ret;
5255 return pos;
5258 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
5259 int64_t pos)
5261 int64_t offset = qcow2_check_vmstate_request(bs, qiov, pos);
5262 if (offset < 0) {
5263 return offset;
5266 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
5267 return bs->drv->bdrv_co_pwritev_part(bs, offset, qiov->size, qiov, 0, 0);
5270 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
5271 int64_t pos)
5273 int64_t offset = qcow2_check_vmstate_request(bs, qiov, pos);
5274 if (offset < 0) {
5275 return offset;
5278 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
5279 return bs->drv->bdrv_co_preadv_part(bs, offset, qiov->size, qiov, 0, 0);
5282 static int qcow2_has_compressed_clusters(BlockDriverState *bs)
5284 int64_t offset = 0;
5285 int64_t bytes = bdrv_getlength(bs);
5287 if (bytes < 0) {
5288 return bytes;
5291 while (bytes != 0) {
5292 int ret;
5293 QCow2SubclusterType type;
5294 unsigned int cur_bytes = MIN(INT_MAX, bytes);
5295 uint64_t host_offset;
5297 ret = qcow2_get_host_offset(bs, offset, &cur_bytes, &host_offset,
5298 &type);
5299 if (ret < 0) {
5300 return ret;
5303 if (type == QCOW2_SUBCLUSTER_COMPRESSED) {
5304 return 1;
5307 offset += cur_bytes;
5308 bytes -= cur_bytes;
5311 return 0;
5315 * Downgrades an image's version. To achieve this, any incompatible features
5316 * have to be removed.
5318 static int qcow2_downgrade(BlockDriverState *bs, int target_version,
5319 BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
5320 Error **errp)
5322 BDRVQcow2State *s = bs->opaque;
5323 int current_version = s->qcow_version;
5324 int ret;
5325 int i;
5327 /* This is qcow2_downgrade(), not qcow2_upgrade() */
5328 assert(target_version < current_version);
5330 /* There are no other versions (now) that you can downgrade to */
5331 assert(target_version == 2);
5333 if (s->refcount_order != 4) {
5334 error_setg(errp, "compat=0.10 requires refcount_bits=16");
5335 return -ENOTSUP;
5338 if (has_data_file(bs)) {
5339 error_setg(errp, "Cannot downgrade an image with a data file");
5340 return -ENOTSUP;
5344 * If any internal snapshot has a different size than the current
5345 * image size, or VM state size that exceeds 32 bits, downgrading
5346 * is unsafe. Even though we would still use v3-compliant output
5347 * to preserve that data, other v2 programs might not realize
5348 * those optional fields are important.
5350 for (i = 0; i < s->nb_snapshots; i++) {
5351 if (s->snapshots[i].vm_state_size > UINT32_MAX ||
5352 s->snapshots[i].disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) {
5353 error_setg(errp, "Internal snapshots prevent downgrade of image");
5354 return -ENOTSUP;
5358 /* clear incompatible features */
5359 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
5360 ret = qcow2_mark_clean(bs);
5361 if (ret < 0) {
5362 error_setg_errno(errp, -ret, "Failed to make the image clean");
5363 return ret;
5367 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
5368 * the first place; if that happens nonetheless, returning -ENOTSUP is the
5369 * best thing to do anyway */
5371 if (s->incompatible_features & ~QCOW2_INCOMPAT_COMPRESSION) {
5372 error_setg(errp, "Cannot downgrade an image with incompatible features "
5373 "0x%" PRIx64 " set",
5374 s->incompatible_features & ~QCOW2_INCOMPAT_COMPRESSION);
5375 return -ENOTSUP;
5378 /* since we can ignore compatible features, we can set them to 0 as well */
5379 s->compatible_features = 0;
5380 /* if lazy refcounts have been used, they have already been fixed through
5381 * clearing the dirty flag */
5383 /* clearing autoclear features is trivial */
5384 s->autoclear_features = 0;
5386 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque);
5387 if (ret < 0) {
5388 error_setg_errno(errp, -ret, "Failed to turn zero into data clusters");
5389 return ret;
5392 if (s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION) {
5393 ret = qcow2_has_compressed_clusters(bs);
5394 if (ret < 0) {
5395 error_setg(errp, "Failed to check block status");
5396 return -EINVAL;
5398 if (ret) {
5399 error_setg(errp, "Cannot downgrade an image with zstd compression "
5400 "type and existing compressed clusters");
5401 return -ENOTSUP;
5404 * No compressed clusters for now, so just chose default zlib
5405 * compression.
5407 s->incompatible_features &= ~QCOW2_INCOMPAT_COMPRESSION;
5408 s->compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
5411 assert(s->incompatible_features == 0);
5413 s->qcow_version = target_version;
5414 ret = qcow2_update_header(bs);
5415 if (ret < 0) {
5416 s->qcow_version = current_version;
5417 error_setg_errno(errp, -ret, "Failed to update the image header");
5418 return ret;
5420 return 0;
5424 * Upgrades an image's version. While newer versions encompass all
5425 * features of older versions, some things may have to be presented
5426 * differently.
5428 static int qcow2_upgrade(BlockDriverState *bs, int target_version,
5429 BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
5430 Error **errp)
5432 BDRVQcow2State *s = bs->opaque;
5433 bool need_snapshot_update;
5434 int current_version = s->qcow_version;
5435 int i;
5436 int ret;
5438 /* This is qcow2_upgrade(), not qcow2_downgrade() */
5439 assert(target_version > current_version);
5441 /* There are no other versions (yet) that you can upgrade to */
5442 assert(target_version == 3);
5444 status_cb(bs, 0, 2, cb_opaque);
5447 * In v2, snapshots do not need to have extra data. v3 requires
5448 * the 64-bit VM state size and the virtual disk size to be
5449 * present.
5450 * qcow2_write_snapshots() will always write the list in the
5451 * v3-compliant format.
5453 need_snapshot_update = false;
5454 for (i = 0; i < s->nb_snapshots; i++) {
5455 if (s->snapshots[i].extra_data_size <
5456 sizeof_field(QCowSnapshotExtraData, vm_state_size_large) +
5457 sizeof_field(QCowSnapshotExtraData, disk_size))
5459 need_snapshot_update = true;
5460 break;
5463 if (need_snapshot_update) {
5464 ret = qcow2_write_snapshots(bs);
5465 if (ret < 0) {
5466 error_setg_errno(errp, -ret, "Failed to update the snapshot table");
5467 return ret;
5470 status_cb(bs, 1, 2, cb_opaque);
5472 s->qcow_version = target_version;
5473 ret = qcow2_update_header(bs);
5474 if (ret < 0) {
5475 s->qcow_version = current_version;
5476 error_setg_errno(errp, -ret, "Failed to update the image header");
5477 return ret;
5479 status_cb(bs, 2, 2, cb_opaque);
5481 return 0;
5484 typedef enum Qcow2AmendOperation {
5485 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be
5486 * statically initialized to so that the helper CB can discern the first
5487 * invocation from an operation change */
5488 QCOW2_NO_OPERATION = 0,
5490 QCOW2_UPGRADING,
5491 QCOW2_UPDATING_ENCRYPTION,
5492 QCOW2_CHANGING_REFCOUNT_ORDER,
5493 QCOW2_DOWNGRADING,
5494 } Qcow2AmendOperation;
5496 typedef struct Qcow2AmendHelperCBInfo {
5497 /* The code coordinating the amend operations should only modify
5498 * these four fields; the rest will be managed by the CB */
5499 BlockDriverAmendStatusCB *original_status_cb;
5500 void *original_cb_opaque;
5502 Qcow2AmendOperation current_operation;
5504 /* Total number of operations to perform (only set once) */
5505 int total_operations;
5507 /* The following fields are managed by the CB */
5509 /* Number of operations completed */
5510 int operations_completed;
5512 /* Cumulative offset of all completed operations */
5513 int64_t offset_completed;
5515 Qcow2AmendOperation last_operation;
5516 int64_t last_work_size;
5517 } Qcow2AmendHelperCBInfo;
5519 static void qcow2_amend_helper_cb(BlockDriverState *bs,
5520 int64_t operation_offset,
5521 int64_t operation_work_size, void *opaque)
5523 Qcow2AmendHelperCBInfo *info = opaque;
5524 int64_t current_work_size;
5525 int64_t projected_work_size;
5527 if (info->current_operation != info->last_operation) {
5528 if (info->last_operation != QCOW2_NO_OPERATION) {
5529 info->offset_completed += info->last_work_size;
5530 info->operations_completed++;
5533 info->last_operation = info->current_operation;
5536 assert(info->total_operations > 0);
5537 assert(info->operations_completed < info->total_operations);
5539 info->last_work_size = operation_work_size;
5541 current_work_size = info->offset_completed + operation_work_size;
5543 /* current_work_size is the total work size for (operations_completed + 1)
5544 * operations (which includes this one), so multiply it by the number of
5545 * operations not covered and divide it by the number of operations
5546 * covered to get a projection for the operations not covered */
5547 projected_work_size = current_work_size * (info->total_operations -
5548 info->operations_completed - 1)
5549 / (info->operations_completed + 1);
5551 info->original_status_cb(bs, info->offset_completed + operation_offset,
5552 current_work_size + projected_work_size,
5553 info->original_cb_opaque);
5556 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
5557 BlockDriverAmendStatusCB *status_cb,
5558 void *cb_opaque,
5559 bool force,
5560 Error **errp)
5562 BDRVQcow2State *s = bs->opaque;
5563 int old_version = s->qcow_version, new_version = old_version;
5564 uint64_t new_size = 0;
5565 const char *backing_file = NULL, *backing_format = NULL, *data_file = NULL;
5566 bool lazy_refcounts = s->use_lazy_refcounts;
5567 bool data_file_raw = data_file_is_raw(bs);
5568 const char *compat = NULL;
5569 int refcount_bits = s->refcount_bits;
5570 int ret;
5571 QemuOptDesc *desc = opts->list->desc;
5572 Qcow2AmendHelperCBInfo helper_cb_info;
5573 bool encryption_update = false;
5575 while (desc && desc->name) {
5576 if (!qemu_opt_find(opts, desc->name)) {
5577 /* only change explicitly defined options */
5578 desc++;
5579 continue;
5582 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) {
5583 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL);
5584 if (!compat) {
5585 /* preserve default */
5586 } else if (!strcmp(compat, "0.10") || !strcmp(compat, "v2")) {
5587 new_version = 2;
5588 } else if (!strcmp(compat, "1.1") || !strcmp(compat, "v3")) {
5589 new_version = 3;
5590 } else {
5591 error_setg(errp, "Unknown compatibility level %s", compat);
5592 return -EINVAL;
5594 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) {
5595 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
5596 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) {
5597 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
5598 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) {
5599 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
5600 } else if (g_str_has_prefix(desc->name, "encrypt.")) {
5601 if (!s->crypto) {
5602 error_setg(errp,
5603 "Can't amend encryption options - encryption not present");
5604 return -EINVAL;
5606 if (s->crypt_method_header != QCOW_CRYPT_LUKS) {
5607 error_setg(errp,
5608 "Only LUKS encryption options can be amended");
5609 return -ENOTSUP;
5611 encryption_update = true;
5612 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) {
5613 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS,
5614 lazy_refcounts);
5615 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) {
5616 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS,
5617 refcount_bits);
5619 if (refcount_bits <= 0 || refcount_bits > 64 ||
5620 !is_power_of_2(refcount_bits))
5622 error_setg(errp, "Refcount width must be a power of two and "
5623 "may not exceed 64 bits");
5624 return -EINVAL;
5626 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE)) {
5627 data_file = qemu_opt_get(opts, BLOCK_OPT_DATA_FILE);
5628 if (data_file && !has_data_file(bs)) {
5629 error_setg(errp, "data-file can only be set for images that "
5630 "use an external data file");
5631 return -EINVAL;
5633 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE_RAW)) {
5634 data_file_raw = qemu_opt_get_bool(opts, BLOCK_OPT_DATA_FILE_RAW,
5635 data_file_raw);
5636 if (data_file_raw && !data_file_is_raw(bs)) {
5637 error_setg(errp, "data-file-raw cannot be set on existing "
5638 "images");
5639 return -EINVAL;
5641 } else {
5642 /* if this point is reached, this probably means a new option was
5643 * added without having it covered here */
5644 abort();
5647 desc++;
5650 helper_cb_info = (Qcow2AmendHelperCBInfo){
5651 .original_status_cb = status_cb,
5652 .original_cb_opaque = cb_opaque,
5653 .total_operations = (new_version != old_version)
5654 + (s->refcount_bits != refcount_bits) +
5655 (encryption_update == true)
5658 /* Upgrade first (some features may require compat=1.1) */
5659 if (new_version > old_version) {
5660 helper_cb_info.current_operation = QCOW2_UPGRADING;
5661 ret = qcow2_upgrade(bs, new_version, &qcow2_amend_helper_cb,
5662 &helper_cb_info, errp);
5663 if (ret < 0) {
5664 return ret;
5668 if (encryption_update) {
5669 QDict *amend_opts_dict;
5670 QCryptoBlockAmendOptions *amend_opts;
5672 helper_cb_info.current_operation = QCOW2_UPDATING_ENCRYPTION;
5673 amend_opts_dict = qcow2_extract_crypto_opts(opts, "luks", errp);
5674 if (!amend_opts_dict) {
5675 return -EINVAL;
5677 amend_opts = block_crypto_amend_opts_init(amend_opts_dict, errp);
5678 qobject_unref(amend_opts_dict);
5679 if (!amend_opts) {
5680 return -EINVAL;
5682 ret = qcrypto_block_amend_options(s->crypto,
5683 qcow2_crypto_hdr_read_func,
5684 qcow2_crypto_hdr_write_func,
5686 amend_opts,
5687 force,
5688 errp);
5689 qapi_free_QCryptoBlockAmendOptions(amend_opts);
5690 if (ret < 0) {
5691 return ret;
5695 if (s->refcount_bits != refcount_bits) {
5696 int refcount_order = ctz32(refcount_bits);
5698 if (new_version < 3 && refcount_bits != 16) {
5699 error_setg(errp, "Refcount widths other than 16 bits require "
5700 "compatibility level 1.1 or above (use compat=1.1 or "
5701 "greater)");
5702 return -EINVAL;
5705 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER;
5706 ret = qcow2_change_refcount_order(bs, refcount_order,
5707 &qcow2_amend_helper_cb,
5708 &helper_cb_info, errp);
5709 if (ret < 0) {
5710 return ret;
5714 /* data-file-raw blocks backing files, so clear it first if requested */
5715 if (data_file_raw) {
5716 s->autoclear_features |= QCOW2_AUTOCLEAR_DATA_FILE_RAW;
5717 } else {
5718 s->autoclear_features &= ~QCOW2_AUTOCLEAR_DATA_FILE_RAW;
5721 if (data_file) {
5722 g_free(s->image_data_file);
5723 s->image_data_file = *data_file ? g_strdup(data_file) : NULL;
5726 ret = qcow2_update_header(bs);
5727 if (ret < 0) {
5728 error_setg_errno(errp, -ret, "Failed to update the image header");
5729 return ret;
5732 if (backing_file || backing_format) {
5733 if (g_strcmp0(backing_file, s->image_backing_file) ||
5734 g_strcmp0(backing_format, s->image_backing_format)) {
5735 error_setg(errp, "Cannot amend the backing file");
5736 error_append_hint(errp,
5737 "You can use 'qemu-img rebase' instead.\n");
5738 return -EINVAL;
5742 if (s->use_lazy_refcounts != lazy_refcounts) {
5743 if (lazy_refcounts) {
5744 if (new_version < 3) {
5745 error_setg(errp, "Lazy refcounts only supported with "
5746 "compatibility level 1.1 and above (use compat=1.1 "
5747 "or greater)");
5748 return -EINVAL;
5750 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
5751 ret = qcow2_update_header(bs);
5752 if (ret < 0) {
5753 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
5754 error_setg_errno(errp, -ret, "Failed to update the image header");
5755 return ret;
5757 s->use_lazy_refcounts = true;
5758 } else {
5759 /* make image clean first */
5760 ret = qcow2_mark_clean(bs);
5761 if (ret < 0) {
5762 error_setg_errno(errp, -ret, "Failed to make the image clean");
5763 return ret;
5765 /* now disallow lazy refcounts */
5766 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
5767 ret = qcow2_update_header(bs);
5768 if (ret < 0) {
5769 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
5770 error_setg_errno(errp, -ret, "Failed to update the image header");
5771 return ret;
5773 s->use_lazy_refcounts = false;
5777 if (new_size) {
5778 BlockBackend *blk = blk_new_with_bs(bs, BLK_PERM_RESIZE, BLK_PERM_ALL,
5779 errp);
5780 if (!blk) {
5781 return -EPERM;
5785 * Amending image options should ensure that the image has
5786 * exactly the given new values, so pass exact=true here.
5788 ret = blk_truncate(blk, new_size, true, PREALLOC_MODE_OFF, 0, errp);
5789 blk_unref(blk);
5790 if (ret < 0) {
5791 return ret;
5795 /* Downgrade last (so unsupported features can be removed before) */
5796 if (new_version < old_version) {
5797 helper_cb_info.current_operation = QCOW2_DOWNGRADING;
5798 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb,
5799 &helper_cb_info, errp);
5800 if (ret < 0) {
5801 return ret;
5805 return 0;
5808 static int coroutine_fn qcow2_co_amend(BlockDriverState *bs,
5809 BlockdevAmendOptions *opts,
5810 bool force,
5811 Error **errp)
5813 BlockdevAmendOptionsQcow2 *qopts = &opts->u.qcow2;
5814 BDRVQcow2State *s = bs->opaque;
5815 int ret = 0;
5817 if (qopts->has_encrypt) {
5818 if (!s->crypto) {
5819 error_setg(errp, "image is not encrypted, can't amend");
5820 return -EOPNOTSUPP;
5823 if (qopts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_LUKS) {
5824 error_setg(errp,
5825 "Amend can't be used to change the qcow2 encryption format");
5826 return -EOPNOTSUPP;
5829 if (s->crypt_method_header != QCOW_CRYPT_LUKS) {
5830 error_setg(errp,
5831 "Only LUKS encryption options can be amended for qcow2 with blockdev-amend");
5832 return -EOPNOTSUPP;
5835 ret = qcrypto_block_amend_options(s->crypto,
5836 qcow2_crypto_hdr_read_func,
5837 qcow2_crypto_hdr_write_func,
5839 qopts->encrypt,
5840 force,
5841 errp);
5843 return ret;
5847 * If offset or size are negative, respectively, they will not be included in
5848 * the BLOCK_IMAGE_CORRUPTED event emitted.
5849 * fatal will be ignored for read-only BDS; corruptions found there will always
5850 * be considered non-fatal.
5852 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
5853 int64_t size, const char *message_format, ...)
5855 BDRVQcow2State *s = bs->opaque;
5856 const char *node_name;
5857 char *message;
5858 va_list ap;
5860 fatal = fatal && bdrv_is_writable(bs);
5862 if (s->signaled_corruption &&
5863 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
5865 return;
5868 va_start(ap, message_format);
5869 message = g_strdup_vprintf(message_format, ap);
5870 va_end(ap);
5872 if (fatal) {
5873 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further "
5874 "corruption events will be suppressed\n", message);
5875 } else {
5876 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal "
5877 "corruption events will be suppressed\n", message);
5880 node_name = bdrv_get_node_name(bs);
5881 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs),
5882 *node_name != '\0', node_name,
5883 message, offset >= 0, offset,
5884 size >= 0, size,
5885 fatal);
5886 g_free(message);
5888 if (fatal) {
5889 qcow2_mark_corrupt(bs);
5890 bs->drv = NULL; /* make BDS unusable */
5893 s->signaled_corruption = true;
5896 #define QCOW_COMMON_OPTIONS \
5898 .name = BLOCK_OPT_SIZE, \
5899 .type = QEMU_OPT_SIZE, \
5900 .help = "Virtual disk size" \
5901 }, \
5903 .name = BLOCK_OPT_COMPAT_LEVEL, \
5904 .type = QEMU_OPT_STRING, \
5905 .help = "Compatibility level (v2 [0.10] or v3 [1.1])" \
5906 }, \
5908 .name = BLOCK_OPT_BACKING_FILE, \
5909 .type = QEMU_OPT_STRING, \
5910 .help = "File name of a base image" \
5911 }, \
5913 .name = BLOCK_OPT_BACKING_FMT, \
5914 .type = QEMU_OPT_STRING, \
5915 .help = "Image format of the base image" \
5916 }, \
5918 .name = BLOCK_OPT_DATA_FILE, \
5919 .type = QEMU_OPT_STRING, \
5920 .help = "File name of an external data file" \
5921 }, \
5923 .name = BLOCK_OPT_DATA_FILE_RAW, \
5924 .type = QEMU_OPT_BOOL, \
5925 .help = "The external data file must stay valid " \
5926 "as a raw image" \
5927 }, \
5929 .name = BLOCK_OPT_LAZY_REFCOUNTS, \
5930 .type = QEMU_OPT_BOOL, \
5931 .help = "Postpone refcount updates", \
5932 .def_value_str = "off" \
5933 }, \
5935 .name = BLOCK_OPT_REFCOUNT_BITS, \
5936 .type = QEMU_OPT_NUMBER, \
5937 .help = "Width of a reference count entry in bits", \
5938 .def_value_str = "16" \
5941 static QemuOptsList qcow2_create_opts = {
5942 .name = "qcow2-create-opts",
5943 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head),
5944 .desc = {
5946 .name = BLOCK_OPT_ENCRYPT, \
5947 .type = QEMU_OPT_BOOL, \
5948 .help = "Encrypt the image with format 'aes'. (Deprecated " \
5949 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", \
5950 }, \
5952 .name = BLOCK_OPT_ENCRYPT_FORMAT, \
5953 .type = QEMU_OPT_STRING, \
5954 .help = "Encrypt the image, format choices: 'aes', 'luks'", \
5955 }, \
5956 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", \
5957 "ID of secret providing qcow AES key or LUKS passphrase"), \
5958 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), \
5959 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), \
5960 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), \
5961 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), \
5962 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), \
5963 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), \
5965 .name = BLOCK_OPT_CLUSTER_SIZE, \
5966 .type = QEMU_OPT_SIZE, \
5967 .help = "qcow2 cluster size", \
5968 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) \
5969 }, \
5971 .name = BLOCK_OPT_EXTL2, \
5972 .type = QEMU_OPT_BOOL, \
5973 .help = "Extended L2 tables", \
5974 .def_value_str = "off" \
5975 }, \
5977 .name = BLOCK_OPT_PREALLOC, \
5978 .type = QEMU_OPT_STRING, \
5979 .help = "Preallocation mode (allowed values: off, " \
5980 "metadata, falloc, full)" \
5981 }, \
5983 .name = BLOCK_OPT_COMPRESSION_TYPE, \
5984 .type = QEMU_OPT_STRING, \
5985 .help = "Compression method used for image cluster " \
5986 "compression", \
5987 .def_value_str = "zlib" \
5989 QCOW_COMMON_OPTIONS,
5990 { /* end of list */ }
5994 static QemuOptsList qcow2_amend_opts = {
5995 .name = "qcow2-amend-opts",
5996 .head = QTAILQ_HEAD_INITIALIZER(qcow2_amend_opts.head),
5997 .desc = {
5998 BLOCK_CRYPTO_OPT_DEF_LUKS_STATE("encrypt."),
5999 BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT("encrypt."),
6000 BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET("encrypt."),
6001 BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET("encrypt."),
6002 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."),
6003 QCOW_COMMON_OPTIONS,
6004 { /* end of list */ }
6008 static const char *const qcow2_strong_runtime_opts[] = {
6009 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
6011 NULL
6014 BlockDriver bdrv_qcow2 = {
6015 .format_name = "qcow2",
6016 .instance_size = sizeof(BDRVQcow2State),
6017 .bdrv_probe = qcow2_probe,
6018 .bdrv_open = qcow2_open,
6019 .bdrv_close = qcow2_close,
6020 .bdrv_reopen_prepare = qcow2_reopen_prepare,
6021 .bdrv_reopen_commit = qcow2_reopen_commit,
6022 .bdrv_reopen_commit_post = qcow2_reopen_commit_post,
6023 .bdrv_reopen_abort = qcow2_reopen_abort,
6024 .bdrv_join_options = qcow2_join_options,
6025 .bdrv_child_perm = bdrv_default_perms,
6026 .bdrv_co_create_opts = qcow2_co_create_opts,
6027 .bdrv_co_create = qcow2_co_create,
6028 .bdrv_has_zero_init = qcow2_has_zero_init,
6029 .bdrv_co_block_status = qcow2_co_block_status,
6031 .bdrv_co_preadv_part = qcow2_co_preadv_part,
6032 .bdrv_co_pwritev_part = qcow2_co_pwritev_part,
6033 .bdrv_co_flush_to_os = qcow2_co_flush_to_os,
6035 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes,
6036 .bdrv_co_pdiscard = qcow2_co_pdiscard,
6037 .bdrv_co_copy_range_from = qcow2_co_copy_range_from,
6038 .bdrv_co_copy_range_to = qcow2_co_copy_range_to,
6039 .bdrv_co_truncate = qcow2_co_truncate,
6040 .bdrv_co_pwritev_compressed_part = qcow2_co_pwritev_compressed_part,
6041 .bdrv_make_empty = qcow2_make_empty,
6043 .bdrv_snapshot_create = qcow2_snapshot_create,
6044 .bdrv_snapshot_goto = qcow2_snapshot_goto,
6045 .bdrv_snapshot_delete = qcow2_snapshot_delete,
6046 .bdrv_snapshot_list = qcow2_snapshot_list,
6047 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp,
6048 .bdrv_measure = qcow2_measure,
6049 .bdrv_get_info = qcow2_get_info,
6050 .bdrv_get_specific_info = qcow2_get_specific_info,
6052 .bdrv_save_vmstate = qcow2_save_vmstate,
6053 .bdrv_load_vmstate = qcow2_load_vmstate,
6055 .is_format = true,
6056 .supports_backing = true,
6057 .bdrv_change_backing_file = qcow2_change_backing_file,
6059 .bdrv_refresh_limits = qcow2_refresh_limits,
6060 .bdrv_co_invalidate_cache = qcow2_co_invalidate_cache,
6061 .bdrv_inactivate = qcow2_inactivate,
6063 .create_opts = &qcow2_create_opts,
6064 .amend_opts = &qcow2_amend_opts,
6065 .strong_runtime_opts = qcow2_strong_runtime_opts,
6066 .mutable_opts = mutable_opts,
6067 .bdrv_co_check = qcow2_co_check,
6068 .bdrv_amend_options = qcow2_amend_options,
6069 .bdrv_co_amend = qcow2_co_amend,
6071 .bdrv_detach_aio_context = qcow2_detach_aio_context,
6072 .bdrv_attach_aio_context = qcow2_attach_aio_context,
6074 .bdrv_supports_persistent_dirty_bitmap =
6075 qcow2_supports_persistent_dirty_bitmap,
6076 .bdrv_co_can_store_new_dirty_bitmap = qcow2_co_can_store_new_dirty_bitmap,
6077 .bdrv_co_remove_persistent_dirty_bitmap =
6078 qcow2_co_remove_persistent_dirty_bitmap,
6081 static void bdrv_qcow2_init(void)
6083 bdrv_register(&bdrv_qcow2);
6086 block_init(bdrv_qcow2_init);