2 * Block driver for the QCOW format
4 * Copyright (c) 2004-2006 Fabrice Bellard
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 #include "qemu/osdep.h"
26 #include "qapi/error.h"
27 #include "qemu/error-report.h"
28 #include "block/block_int.h"
29 #include "block/qdict.h"
30 #include "sysemu/block-backend.h"
31 #include "qemu/module.h"
32 #include "qemu/option.h"
33 #include "qemu/bswap.h"
34 #include "qemu/cutils.h"
35 #include "qemu/memalign.h"
37 #include "qapi/qmp/qdict.h"
38 #include "qapi/qmp/qstring.h"
39 #include "qapi/qobject-input-visitor.h"
40 #include "qapi/qapi-visit-block-core.h"
41 #include "crypto/block.h"
42 #include "migration/blocker.h"
45 /**************************************************************/
46 /* QEMU COW block driver with compression and encryption support */
48 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
49 #define QCOW_VERSION 1
51 #define QCOW_CRYPT_NONE 0
52 #define QCOW_CRYPT_AES 1
54 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
56 typedef struct QCowHeader {
59 uint64_t backing_file_offset;
60 uint32_t backing_file_size;
62 uint64_t size; /* in bytes */
66 uint32_t crypt_method;
67 uint64_t l1_table_offset;
68 } QEMU_PACKED QCowHeader;
70 #define L2_CACHE_SIZE 16
72 typedef struct BDRVQcowState {
78 uint64_t cluster_offset_mask;
79 uint64_t l1_table_offset;
82 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
83 uint32_t l2_cache_counts[L2_CACHE_SIZE];
84 uint8_t *cluster_cache;
85 uint8_t *cluster_data;
86 uint64_t cluster_cache_offset;
87 QCryptoBlock *crypto; /* Disk encryption format driver */
88 uint32_t crypt_method_header;
90 Error *migration_blocker;
93 static QemuOptsList qcow_create_opts;
95 static int coroutine_fn GRAPH_RDLOCK
96 decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
98 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
100 const QCowHeader *cow_header = (const void *)buf;
102 if (buf_size >= sizeof(QCowHeader) &&
103 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
104 be32_to_cpu(cow_header->version) == QCOW_VERSION)
110 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
113 BDRVQcowState *s = bs->opaque;
114 unsigned int len, i, shift;
117 QCryptoBlockOpenOptions *crypto_opts = NULL;
118 unsigned int cflags = 0;
119 QDict *encryptopts = NULL;
120 const char *encryptfmt;
122 qdict_extract_subqdict(options, &encryptopts, "encrypt.");
123 encryptfmt = qdict_get_try_str(encryptopts, "format");
125 ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
130 ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0);
134 header.magic = be32_to_cpu(header.magic);
135 header.version = be32_to_cpu(header.version);
136 header.backing_file_offset = be64_to_cpu(header.backing_file_offset);
137 header.backing_file_size = be32_to_cpu(header.backing_file_size);
138 header.mtime = be32_to_cpu(header.mtime);
139 header.size = be64_to_cpu(header.size);
140 header.crypt_method = be32_to_cpu(header.crypt_method);
141 header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
143 if (header.magic != QCOW_MAGIC) {
144 error_setg(errp, "Image not in qcow format");
148 if (header.version != QCOW_VERSION) {
149 error_setg(errp, "qcow (v%d) does not support qcow version %" PRIu32,
150 QCOW_VERSION, header.version);
151 if (header.version == 2 || header.version == 3) {
152 error_append_hint(errp, "Try the 'qcow2' driver instead.\n");
159 if (header.size <= 1) {
160 error_setg(errp, "Image size is too small (must be at least 2 bytes)");
164 if (header.cluster_bits < 9 || header.cluster_bits > 16) {
165 error_setg(errp, "Cluster size must be between 512 and 64k");
170 /* l2_bits specifies number of entries; storing a uint64_t in each entry,
171 * so bytes = num_entries << 3. */
172 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
173 error_setg(errp, "L2 table size must be between 512 and 64k");
178 s->crypt_method_header = header.crypt_method;
179 if (s->crypt_method_header) {
180 if (bdrv_uses_whitelist() &&
181 s->crypt_method_header == QCOW_CRYPT_AES) {
183 "Use of AES-CBC encrypted qcow images is no longer "
184 "supported in system emulators");
185 error_append_hint(errp,
186 "You can use 'qemu-img convert' to convert your "
187 "image to an alternative supported format, such "
188 "as unencrypted qcow, or raw with the LUKS "
189 "format instead.\n");
193 if (s->crypt_method_header == QCOW_CRYPT_AES) {
194 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
196 "Header reported 'aes' encryption format but "
197 "options specify '%s'", encryptfmt);
201 qdict_put_str(encryptopts, "format", "qcow");
202 crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
208 if (flags & BDRV_O_NO_IO) {
209 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
211 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.",
212 NULL, NULL, cflags, 1, errp);
218 error_setg(errp, "invalid encryption method in qcow header");
222 bs->encrypted = true;
225 error_setg(errp, "No encryption in image header, but options "
226 "specified format '%s'", encryptfmt);
231 s->cluster_bits = header.cluster_bits;
232 s->cluster_size = 1 << s->cluster_bits;
233 s->l2_bits = header.l2_bits;
234 s->l2_size = 1 << s->l2_bits;
235 bs->total_sectors = header.size / 512;
236 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
238 /* read the level 1 table */
239 shift = s->cluster_bits + s->l2_bits;
240 if (header.size > UINT64_MAX - (1LL << shift)) {
241 error_setg(errp, "Image too large");
245 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
246 if (l1_size > INT_MAX / sizeof(uint64_t)) {
247 error_setg(errp, "Image too large");
251 s->l1_size = l1_size;
254 s->l1_table_offset = header.l1_table_offset;
255 s->l1_table = g_try_new(uint64_t, s->l1_size);
256 if (s->l1_table == NULL) {
257 error_setg(errp, "Could not allocate memory for L1 table");
262 ret = bdrv_pread(bs->file, s->l1_table_offset,
263 s->l1_size * sizeof(uint64_t), s->l1_table, 0);
268 for(i = 0;i < s->l1_size; i++) {
269 s->l1_table[i] = be64_to_cpu(s->l1_table[i]);
272 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
274 qemu_try_blockalign(bs->file->bs,
275 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
276 if (s->l2_cache == NULL) {
277 error_setg(errp, "Could not allocate L2 table cache");
281 s->cluster_cache = g_malloc(s->cluster_size);
282 s->cluster_data = g_malloc(s->cluster_size);
283 s->cluster_cache_offset = -1;
285 /* read the backing file name */
286 if (header.backing_file_offset != 0) {
287 len = header.backing_file_size;
288 if (len > 1023 || len >= sizeof(bs->backing_file)) {
289 error_setg(errp, "Backing file name too long");
293 ret = bdrv_pread(bs->file, header.backing_file_offset, len,
294 bs->auto_backing_file, 0);
298 bs->auto_backing_file[len] = '\0';
299 pstrcpy(bs->backing_file, sizeof(bs->backing_file),
300 bs->auto_backing_file);
303 /* Disable migration when qcow images are used */
304 bdrv_graph_rdlock_main_loop();
305 error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
306 "does not support live migration",
307 bdrv_get_device_or_node_name(bs));
308 bdrv_graph_rdunlock_main_loop();
310 ret = migrate_add_blocker_normal(&s->migration_blocker, errp);
315 qobject_unref(encryptopts);
316 qapi_free_QCryptoBlockOpenOptions(crypto_opts);
317 qemu_co_mutex_init(&s->lock);
322 qemu_vfree(s->l2_cache);
323 g_free(s->cluster_cache);
324 g_free(s->cluster_data);
325 qcrypto_block_free(s->crypto);
326 qobject_unref(encryptopts);
327 qapi_free_QCryptoBlockOpenOptions(crypto_opts);
332 /* We have nothing to do for QCOW reopen, stubs just return
334 static int qcow_reopen_prepare(BDRVReopenState *state,
335 BlockReopenQueue *queue, Error **errp)
345 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start'
346 * to 'n_end' within the cluster)
348 * 2 to allocate a compressed cluster of size
349 * 'compressed_size'. 'compressed_size' must be > 0 and <
352 * return 0 if not allocated, 1 if *result is assigned, and negative
355 static int coroutine_fn GRAPH_RDLOCK
356 get_cluster_offset(BlockDriverState *bs, uint64_t offset, int allocate,
357 int compressed_size, int n_start, int n_end,
360 BDRVQcowState *s = bs->opaque;
361 int min_index, i, j, l1_index, l2_index, ret;
363 uint64_t *l2_table, cluster_offset, tmp;
368 l1_index = offset >> (s->l2_bits + s->cluster_bits);
369 l2_offset = s->l1_table[l1_index];
374 /* allocate a new l2 entry */
375 l2_offset = bdrv_co_getlength(bs->file->bs);
379 /* round to cluster size */
380 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size);
381 /* update the L1 entry */
382 s->l1_table[l1_index] = l2_offset;
383 tmp = cpu_to_be64(l2_offset);
384 BLKDBG_CO_EVENT(bs->file, BLKDBG_L1_UPDATE);
385 ret = bdrv_co_pwrite_sync(bs->file,
386 s->l1_table_offset + l1_index * sizeof(tmp),
387 sizeof(tmp), &tmp, 0);
393 for(i = 0; i < L2_CACHE_SIZE; i++) {
394 if (l2_offset == s->l2_cache_offsets[i]) {
395 /* increment the hit count */
396 if (++s->l2_cache_counts[i] == 0xffffffff) {
397 for(j = 0; j < L2_CACHE_SIZE; j++) {
398 s->l2_cache_counts[j] >>= 1;
401 l2_table = s->l2_cache + (i << s->l2_bits);
405 /* not found: load a new entry in the least used one */
407 min_count = 0xffffffff;
408 for(i = 0; i < L2_CACHE_SIZE; i++) {
409 if (s->l2_cache_counts[i] < min_count) {
410 min_count = s->l2_cache_counts[i];
414 l2_table = s->l2_cache + (min_index << s->l2_bits);
415 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_LOAD);
417 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
418 ret = bdrv_co_pwrite_sync(bs->file, l2_offset,
419 s->l2_size * sizeof(uint64_t), l2_table, 0);
424 ret = bdrv_co_pread(bs->file, l2_offset,
425 s->l2_size * sizeof(uint64_t), l2_table, 0);
430 s->l2_cache_offsets[min_index] = l2_offset;
431 s->l2_cache_counts[min_index] = 1;
433 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
434 cluster_offset = be64_to_cpu(l2_table[l2_index]);
435 if (!cluster_offset ||
436 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
439 BLKDBG_CO_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
440 assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE));
441 /* allocate a new cluster */
442 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
443 (n_end - n_start) < s->cluster_size) {
444 /* if the cluster is already compressed, we must
445 decompress it in the case it is not completely
447 if (decompress_cluster(bs, cluster_offset) < 0) {
450 cluster_offset = bdrv_co_getlength(bs->file->bs);
451 if ((int64_t) cluster_offset < 0) {
452 return cluster_offset;
454 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
455 /* write the cluster content */
456 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
457 ret = bdrv_co_pwrite(bs->file, cluster_offset, s->cluster_size,
458 s->cluster_cache, 0);
463 cluster_offset = bdrv_co_getlength(bs->file->bs);
464 if ((int64_t) cluster_offset < 0) {
465 return cluster_offset;
468 /* round to cluster size */
469 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
470 if (cluster_offset + s->cluster_size > INT64_MAX) {
473 ret = bdrv_co_truncate(bs->file,
474 cluster_offset + s->cluster_size,
475 false, PREALLOC_MODE_OFF, 0, NULL);
479 /* if encrypted, we must initialize the cluster
480 content which won't be written */
482 (n_end - n_start) < s->cluster_size) {
483 uint64_t start_offset;
485 start_offset = offset & ~(s->cluster_size - 1);
486 for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) {
487 if (i < n_start || i >= n_end) {
488 memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE);
489 if (qcrypto_block_encrypt(s->crypto,
496 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
497 ret = bdrv_co_pwrite(bs->file, cluster_offset + i,
506 } else if (allocate == 2) {
507 cluster_offset |= QCOW_OFLAG_COMPRESSED |
508 (uint64_t)compressed_size << (63 - s->cluster_bits);
511 /* update L2 table */
512 tmp = cpu_to_be64(cluster_offset);
513 l2_table[l2_index] = tmp;
515 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
517 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE);
519 ret = bdrv_co_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
520 sizeof(tmp), &tmp, 0);
525 *result = cluster_offset;
529 static int coroutine_fn GRAPH_RDLOCK
530 qcow_co_block_status(BlockDriverState *bs, bool want_zero,
531 int64_t offset, int64_t bytes, int64_t *pnum,
532 int64_t *map, BlockDriverState **file)
534 BDRVQcowState *s = bs->opaque;
535 int index_in_cluster, ret;
537 uint64_t cluster_offset;
539 qemu_co_mutex_lock(&s->lock);
540 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
541 qemu_co_mutex_unlock(&s->lock);
545 index_in_cluster = offset & (s->cluster_size - 1);
546 n = s->cluster_size - index_in_cluster;
551 if (!cluster_offset) {
554 if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
555 return BDRV_BLOCK_DATA | BDRV_BLOCK_COMPRESSED;
558 return BDRV_BLOCK_DATA;
560 *map = cluster_offset | index_in_cluster;
561 *file = bs->file->bs;
562 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
565 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
566 const uint8_t *buf, int buf_size)
568 z_stream strm1, *strm = &strm1;
571 memset(strm, 0, sizeof(*strm));
573 strm->next_in = (uint8_t *)buf;
574 strm->avail_in = buf_size;
575 strm->next_out = out_buf;
576 strm->avail_out = out_buf_size;
578 ret = inflateInit2(strm, -12);
581 ret = inflate(strm, Z_FINISH);
582 out_len = strm->next_out - out_buf;
583 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
584 out_len != out_buf_size) {
592 static int coroutine_fn GRAPH_RDLOCK
593 decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
595 BDRVQcowState *s = bs->opaque;
599 coffset = cluster_offset & s->cluster_offset_mask;
600 if (s->cluster_cache_offset != coffset) {
601 csize = cluster_offset >> (63 - s->cluster_bits);
602 csize &= (s->cluster_size - 1);
603 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
604 ret = bdrv_co_pread(bs->file, coffset, csize, s->cluster_data, 0);
607 if (decompress_buffer(s->cluster_cache, s->cluster_size,
608 s->cluster_data, csize) < 0) {
611 s->cluster_cache_offset = coffset;
616 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp)
618 /* At least encrypted images require 512-byte alignment. Apply the
619 * limit universally, rather than just on encrypted images, as
620 * it's easier to let the block layer handle rounding than to
621 * audit this code further. */
622 bs->bl.request_alignment = BDRV_SECTOR_SIZE;
625 static int coroutine_fn GRAPH_RDLOCK
626 qcow_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
627 QEMUIOVector *qiov, BdrvRequestFlags flags)
629 BDRVQcowState *s = bs->opaque;
630 int offset_in_cluster;
632 uint64_t cluster_offset;
636 if (qiov->niov > 1) {
637 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
643 buf = (uint8_t *)qiov->iov->iov_base;
646 qemu_co_mutex_lock(&s->lock);
649 /* prepare next request */
650 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
654 offset_in_cluster = offset & (s->cluster_size - 1);
655 n = s->cluster_size - offset_in_cluster;
660 if (!cluster_offset) {
662 /* read from the base image */
663 qemu_co_mutex_unlock(&s->lock);
664 /* qcow2 emits this on bs->file instead of bs->backing */
665 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
666 ret = bdrv_co_pread(bs->backing, offset, n, buf, 0);
667 qemu_co_mutex_lock(&s->lock);
672 /* Note: in this case, no need to wait */
675 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
676 /* add AIO support for compressed blocks ? */
677 if (decompress_cluster(bs, cluster_offset) < 0) {
681 memcpy(buf, s->cluster_cache + offset_in_cluster, n);
683 if ((cluster_offset & 511) != 0) {
687 qemu_co_mutex_unlock(&s->lock);
688 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_AIO);
689 ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster,
691 qemu_co_mutex_lock(&s->lock);
697 if (qcrypto_block_decrypt(s->crypto,
698 offset, buf, n, NULL) < 0) {
711 qemu_co_mutex_unlock(&s->lock);
713 if (qiov->niov > 1) {
714 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
715 qemu_vfree(orig_buf);
721 static int coroutine_fn GRAPH_RDLOCK
722 qcow_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
723 QEMUIOVector *qiov, BdrvRequestFlags flags)
725 BDRVQcowState *s = bs->opaque;
726 int offset_in_cluster;
727 uint64_t cluster_offset;
732 s->cluster_cache_offset = -1; /* disable compressed cache */
734 /* We must always copy the iov when encrypting, so we
735 * don't modify the original data buffer during encryption */
736 if (bs->encrypted || qiov->niov > 1) {
737 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
741 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
744 buf = (uint8_t *)qiov->iov->iov_base;
747 qemu_co_mutex_lock(&s->lock);
750 offset_in_cluster = offset & (s->cluster_size - 1);
751 n = s->cluster_size - offset_in_cluster;
755 ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster,
756 offset_in_cluster + n, &cluster_offset);
760 if (!cluster_offset || (cluster_offset & 511) != 0) {
766 if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) {
772 qemu_co_mutex_unlock(&s->lock);
773 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
774 ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster,
776 qemu_co_mutex_lock(&s->lock);
786 qemu_co_mutex_unlock(&s->lock);
788 qemu_vfree(orig_buf);
793 static void qcow_close(BlockDriverState *bs)
795 BDRVQcowState *s = bs->opaque;
797 qcrypto_block_free(s->crypto);
800 qemu_vfree(s->l2_cache);
801 g_free(s->cluster_cache);
802 g_free(s->cluster_data);
804 migrate_del_blocker(&s->migration_blocker);
807 static int coroutine_fn GRAPH_UNLOCKED
808 qcow_co_create(BlockdevCreateOptions *opts, Error **errp)
810 BlockdevCreateOptionsQcow *qcow_opts;
811 int header_size, backing_filename_len, l1_size, shift, i;
814 int64_t total_size = 0;
816 BlockDriverState *bs;
817 BlockBackend *qcow_blk;
818 QCryptoBlock *crypto = NULL;
820 assert(opts->driver == BLOCKDEV_DRIVER_QCOW);
821 qcow_opts = &opts->u.qcow;
824 total_size = qcow_opts->size;
825 if (total_size == 0) {
826 error_setg(errp, "Image size is too small, cannot be zero length");
830 if (qcow_opts->encrypt &&
831 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW)
833 error_setg(errp, "Unsupported encryption format");
837 /* Create BlockBackend to write to the image */
838 bs = bdrv_co_open_blockdev_ref(qcow_opts->file, errp);
843 qcow_blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE,
849 blk_set_allow_write_beyond_eof(qcow_blk, true);
851 /* Create image format */
852 memset(&header, 0, sizeof(header));
853 header.magic = cpu_to_be32(QCOW_MAGIC);
854 header.version = cpu_to_be32(QCOW_VERSION);
855 header.size = cpu_to_be64(total_size);
856 header_size = sizeof(header);
857 backing_filename_len = 0;
858 if (qcow_opts->backing_file) {
859 if (strcmp(qcow_opts->backing_file, "fat:")) {
860 header.backing_file_offset = cpu_to_be64(header_size);
861 backing_filename_len = strlen(qcow_opts->backing_file);
862 header.backing_file_size = cpu_to_be32(backing_filename_len);
863 header_size += backing_filename_len;
865 /* special backing file for vvfat */
866 qcow_opts->backing_file = NULL;
868 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
869 unmodified sectors */
870 header.l2_bits = 12; /* 32 KB L2 tables */
872 header.cluster_bits = 12; /* 4 KB clusters */
873 header.l2_bits = 9; /* 4 KB L2 tables */
875 header_size = (header_size + 7) & ~7;
876 shift = header.cluster_bits + header.l2_bits;
877 l1_size = (total_size + (1LL << shift) - 1) >> shift;
879 header.l1_table_offset = cpu_to_be64(header_size);
881 if (qcow_opts->encrypt) {
882 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
884 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.",
885 NULL, NULL, NULL, errp);
891 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
894 /* write all the data */
895 ret = blk_co_pwrite(qcow_blk, 0, sizeof(header), &header, 0);
900 if (qcow_opts->backing_file) {
901 ret = blk_co_pwrite(qcow_blk, sizeof(header), backing_filename_len,
902 qcow_opts->backing_file, 0);
908 tmp = g_malloc0(BDRV_SECTOR_SIZE);
909 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
911 ret = blk_co_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
912 BDRV_SECTOR_SIZE, tmp, 0);
922 blk_co_unref(qcow_blk);
924 qcrypto_block_free(crypto);
928 static int coroutine_fn GRAPH_UNLOCKED
929 qcow_co_create_opts(BlockDriver *drv, const char *filename,
930 QemuOpts *opts, Error **errp)
932 BlockdevCreateOptions *create_options = NULL;
933 BlockDriverState *bs = NULL;
940 static const QDictRenames opt_renames[] = {
941 { BLOCK_OPT_BACKING_FILE, "backing-file" },
942 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
947 * We can't actually store a backing format, but can check that
948 * the user's request made sense.
950 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
951 if (backing_fmt && !bdrv_find_format(backing_fmt)) {
952 error_setg(errp, "unrecognized backing format '%s'", backing_fmt);
957 /* Parse options and convert legacy syntax */
958 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);
960 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
961 if (val && !strcmp(val, "on")) {
962 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
963 } else if (val && !strcmp(val, "off")) {
964 qdict_del(qdict, BLOCK_OPT_ENCRYPT);
967 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
968 if (val && !strcmp(val, "aes")) {
969 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
972 if (!qdict_rename_keys(qdict, opt_renames, errp)) {
977 /* Create and open the file (protocol layer) */
978 ret = bdrv_co_create_file(filename, opts, errp);
983 bs = bdrv_co_open(filename, NULL, NULL,
984 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
990 /* Now get the QAPI type BlockdevCreateOptions */
991 qdict_put_str(qdict, "driver", "qcow");
992 qdict_put_str(qdict, "file", bs->node_name);
994 v = qobject_input_visitor_new_flat_confused(qdict, errp);
1000 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
1002 if (!create_options) {
1007 /* Silently round up size */
1008 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW);
1009 create_options->u.qcow.size =
1010 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE);
1012 /* Create the qcow image (format layer) */
1013 ret = qcow_co_create(create_options, errp);
1020 g_free(backing_fmt);
1021 qobject_unref(qdict);
1023 qapi_free_BlockdevCreateOptions(create_options);
1027 static int qcow_make_empty(BlockDriverState *bs)
1029 BDRVQcowState *s = bs->opaque;
1030 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1033 memset(s->l1_table, 0, l1_length);
1034 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, l1_length, s->l1_table,
1037 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, false,
1038 PREALLOC_MODE_OFF, 0, NULL);
1042 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
1043 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
1044 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
1049 /* XXX: put compressed sectors first, then all the cluster aligned
1050 tables to avoid losing bytes in alignment */
1051 static int coroutine_fn GRAPH_RDLOCK
1052 qcow_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes,
1055 BDRVQcowState *s = bs->opaque;
1058 uint8_t *buf, *out_buf;
1059 uint64_t cluster_offset;
1061 buf = qemu_blockalign(bs, s->cluster_size);
1062 if (bytes != s->cluster_size) {
1063 if (bytes > s->cluster_size ||
1064 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
1069 /* Zero-pad last write if image size is not cluster aligned */
1070 memset(buf + bytes, 0, s->cluster_size - bytes);
1072 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
1074 out_buf = g_malloc(s->cluster_size);
1076 /* best compression, small window, no zlib header */
1077 memset(&strm, 0, sizeof(strm));
1078 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1080 9, Z_DEFAULT_STRATEGY);
1086 strm.avail_in = s->cluster_size;
1087 strm.next_in = (uint8_t *)buf;
1088 strm.avail_out = s->cluster_size;
1089 strm.next_out = out_buf;
1091 ret = deflate(&strm, Z_FINISH);
1092 if (ret != Z_STREAM_END && ret != Z_OK) {
1097 out_len = strm.next_out - out_buf;
1101 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1102 /* could not compress: write normal cluster */
1103 ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0);
1109 qemu_co_mutex_lock(&s->lock);
1110 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
1111 qemu_co_mutex_unlock(&s->lock);
1115 if (cluster_offset == 0) {
1119 cluster_offset &= s->cluster_offset_mask;
1121 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1122 ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0);
1134 static int coroutine_fn
1135 qcow_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1137 BDRVQcowState *s = bs->opaque;
1138 bdi->cluster_size = s->cluster_size;
1142 static QemuOptsList qcow_create_opts = {
1143 .name = "qcow-create-opts",
1144 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1147 .name = BLOCK_OPT_SIZE,
1148 .type = QEMU_OPT_SIZE,
1149 .help = "Virtual disk size"
1152 .name = BLOCK_OPT_BACKING_FILE,
1153 .type = QEMU_OPT_STRING,
1154 .help = "File name of a base image"
1157 .name = BLOCK_OPT_BACKING_FMT,
1158 .type = QEMU_OPT_STRING,
1159 .help = "Format of the backing image",
1162 .name = BLOCK_OPT_ENCRYPT,
1163 .type = QEMU_OPT_BOOL,
1164 .help = "Encrypt the image with format 'aes'. (Deprecated "
1165 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
1168 .name = BLOCK_OPT_ENCRYPT_FORMAT,
1169 .type = QEMU_OPT_STRING,
1170 .help = "Encrypt the image, format choices: 'aes'",
1172 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1173 { /* end of list */ }
1177 static const char *const qcow_strong_runtime_opts[] = {
1178 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
1183 static BlockDriver bdrv_qcow = {
1184 .format_name = "qcow",
1185 .instance_size = sizeof(BDRVQcowState),
1186 .bdrv_probe = qcow_probe,
1187 .bdrv_open = qcow_open,
1188 .bdrv_close = qcow_close,
1189 .bdrv_child_perm = bdrv_default_perms,
1190 .bdrv_reopen_prepare = qcow_reopen_prepare,
1191 .bdrv_co_create = qcow_co_create,
1192 .bdrv_co_create_opts = qcow_co_create_opts,
1193 .bdrv_has_zero_init = bdrv_has_zero_init_1,
1195 .supports_backing = true,
1196 .bdrv_refresh_limits = qcow_refresh_limits,
1198 .bdrv_co_preadv = qcow_co_preadv,
1199 .bdrv_co_pwritev = qcow_co_pwritev,
1200 .bdrv_co_block_status = qcow_co_block_status,
1202 .bdrv_make_empty = qcow_make_empty,
1203 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
1204 .bdrv_co_get_info = qcow_co_get_info,
1206 .create_opts = &qcow_create_opts,
1207 .strong_runtime_opts = qcow_strong_runtime_opts,
1210 static void bdrv_qcow_init(void)
1212 bdrv_register(&bdrv_qcow);
1215 block_init(bdrv_qcow_init);