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 bdrv_graph_rdlock_main_loop();
132 ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0);
136 header.magic = be32_to_cpu(header.magic);
137 header.version = be32_to_cpu(header.version);
138 header.backing_file_offset = be64_to_cpu(header.backing_file_offset);
139 header.backing_file_size = be32_to_cpu(header.backing_file_size);
140 header.mtime = be32_to_cpu(header.mtime);
141 header.size = be64_to_cpu(header.size);
142 header.crypt_method = be32_to_cpu(header.crypt_method);
143 header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
145 if (header.magic != QCOW_MAGIC) {
146 error_setg(errp, "Image not in qcow format");
150 if (header.version != QCOW_VERSION) {
151 error_setg(errp, "qcow (v%d) does not support qcow version %" PRIu32,
152 QCOW_VERSION, header.version);
153 if (header.version == 2 || header.version == 3) {
154 error_append_hint(errp, "Try the 'qcow2' driver instead.\n");
161 if (header.size <= 1) {
162 error_setg(errp, "Image size is too small (must be at least 2 bytes)");
166 if (header.cluster_bits < 9 || header.cluster_bits > 16) {
167 error_setg(errp, "Cluster size must be between 512 and 64k");
172 /* l2_bits specifies number of entries; storing a uint64_t in each entry,
173 * so bytes = num_entries << 3. */
174 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
175 error_setg(errp, "L2 table size must be between 512 and 64k");
180 s->crypt_method_header = header.crypt_method;
181 if (s->crypt_method_header) {
182 if (bdrv_uses_whitelist() &&
183 s->crypt_method_header == QCOW_CRYPT_AES) {
185 "Use of AES-CBC encrypted qcow images is no longer "
186 "supported in system emulators");
187 error_append_hint(errp,
188 "You can use 'qemu-img convert' to convert your "
189 "image to an alternative supported format, such "
190 "as unencrypted qcow, or raw with the LUKS "
191 "format instead.\n");
195 if (s->crypt_method_header == QCOW_CRYPT_AES) {
196 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
198 "Header reported 'aes' encryption format but "
199 "options specify '%s'", encryptfmt);
203 qdict_put_str(encryptopts, "format", "qcow");
204 crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
210 if (flags & BDRV_O_NO_IO) {
211 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
213 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.",
214 NULL, NULL, cflags, 1, errp);
220 error_setg(errp, "invalid encryption method in qcow header");
224 bs->encrypted = true;
227 error_setg(errp, "No encryption in image header, but options "
228 "specified format '%s'", encryptfmt);
233 s->cluster_bits = header.cluster_bits;
234 s->cluster_size = 1 << s->cluster_bits;
235 s->l2_bits = header.l2_bits;
236 s->l2_size = 1 << s->l2_bits;
237 bs->total_sectors = header.size / 512;
238 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
240 /* read the level 1 table */
241 shift = s->cluster_bits + s->l2_bits;
242 if (header.size > UINT64_MAX - (1LL << shift)) {
243 error_setg(errp, "Image too large");
247 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
248 if (l1_size > INT_MAX / sizeof(uint64_t)) {
249 error_setg(errp, "Image too large");
253 s->l1_size = l1_size;
256 s->l1_table_offset = header.l1_table_offset;
257 s->l1_table = g_try_new(uint64_t, s->l1_size);
258 if (s->l1_table == NULL) {
259 error_setg(errp, "Could not allocate memory for L1 table");
264 ret = bdrv_pread(bs->file, s->l1_table_offset,
265 s->l1_size * sizeof(uint64_t), s->l1_table, 0);
270 for(i = 0;i < s->l1_size; i++) {
271 s->l1_table[i] = be64_to_cpu(s->l1_table[i]);
274 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
276 qemu_try_blockalign(bs->file->bs,
277 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
278 if (s->l2_cache == NULL) {
279 error_setg(errp, "Could not allocate L2 table cache");
283 s->cluster_cache = g_malloc(s->cluster_size);
284 s->cluster_data = g_malloc(s->cluster_size);
285 s->cluster_cache_offset = -1;
287 /* read the backing file name */
288 if (header.backing_file_offset != 0) {
289 len = header.backing_file_size;
290 if (len > 1023 || len >= sizeof(bs->backing_file)) {
291 error_setg(errp, "Backing file name too long");
295 ret = bdrv_pread(bs->file, header.backing_file_offset, len,
296 bs->auto_backing_file, 0);
300 bs->auto_backing_file[len] = '\0';
301 pstrcpy(bs->backing_file, sizeof(bs->backing_file),
302 bs->auto_backing_file);
305 /* Disable migration when qcow images are used */
306 error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
307 "does not support live migration",
308 bdrv_get_device_or_node_name(bs));
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);
318 bdrv_graph_rdunlock_main_loop();
322 bdrv_graph_rdunlock_main_loop();
325 qemu_vfree(s->l2_cache);
326 g_free(s->cluster_cache);
327 g_free(s->cluster_data);
328 qcrypto_block_free(s->crypto);
329 qobject_unref(encryptopts);
330 qapi_free_QCryptoBlockOpenOptions(crypto_opts);
335 /* We have nothing to do for QCOW reopen, stubs just return
337 static int qcow_reopen_prepare(BDRVReopenState *state,
338 BlockReopenQueue *queue, Error **errp)
348 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start'
349 * to 'n_end' within the cluster)
351 * 2 to allocate a compressed cluster of size
352 * 'compressed_size'. 'compressed_size' must be > 0 and <
355 * return 0 if not allocated, 1 if *result is assigned, and negative
358 static int coroutine_fn GRAPH_RDLOCK
359 get_cluster_offset(BlockDriverState *bs, uint64_t offset, int allocate,
360 int compressed_size, int n_start, int n_end,
363 BDRVQcowState *s = bs->opaque;
364 int min_index, i, j, l1_index, l2_index, ret;
366 uint64_t *l2_table, cluster_offset, tmp;
371 l1_index = offset >> (s->l2_bits + s->cluster_bits);
372 l2_offset = s->l1_table[l1_index];
377 /* allocate a new l2 entry */
378 l2_offset = bdrv_co_getlength(bs->file->bs);
382 /* round to cluster size */
383 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size);
384 /* update the L1 entry */
385 s->l1_table[l1_index] = l2_offset;
386 tmp = cpu_to_be64(l2_offset);
387 BLKDBG_CO_EVENT(bs->file, BLKDBG_L1_UPDATE);
388 ret = bdrv_co_pwrite_sync(bs->file,
389 s->l1_table_offset + l1_index * sizeof(tmp),
390 sizeof(tmp), &tmp, 0);
396 for(i = 0; i < L2_CACHE_SIZE; i++) {
397 if (l2_offset == s->l2_cache_offsets[i]) {
398 /* increment the hit count */
399 if (++s->l2_cache_counts[i] == 0xffffffff) {
400 for(j = 0; j < L2_CACHE_SIZE; j++) {
401 s->l2_cache_counts[j] >>= 1;
404 l2_table = s->l2_cache + (i << s->l2_bits);
408 /* not found: load a new entry in the least used one */
410 min_count = 0xffffffff;
411 for(i = 0; i < L2_CACHE_SIZE; i++) {
412 if (s->l2_cache_counts[i] < min_count) {
413 min_count = s->l2_cache_counts[i];
417 l2_table = s->l2_cache + (min_index << s->l2_bits);
418 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_LOAD);
420 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
421 ret = bdrv_co_pwrite_sync(bs->file, l2_offset,
422 s->l2_size * sizeof(uint64_t), l2_table, 0);
427 ret = bdrv_co_pread(bs->file, l2_offset,
428 s->l2_size * sizeof(uint64_t), l2_table, 0);
433 s->l2_cache_offsets[min_index] = l2_offset;
434 s->l2_cache_counts[min_index] = 1;
436 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
437 cluster_offset = be64_to_cpu(l2_table[l2_index]);
438 if (!cluster_offset ||
439 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
442 BLKDBG_CO_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
443 assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE));
444 /* allocate a new cluster */
445 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
446 (n_end - n_start) < s->cluster_size) {
447 /* if the cluster is already compressed, we must
448 decompress it in the case it is not completely
450 if (decompress_cluster(bs, cluster_offset) < 0) {
453 cluster_offset = bdrv_co_getlength(bs->file->bs);
454 if ((int64_t) cluster_offset < 0) {
455 return cluster_offset;
457 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
458 /* write the cluster content */
459 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
460 ret = bdrv_co_pwrite(bs->file, cluster_offset, s->cluster_size,
461 s->cluster_cache, 0);
466 cluster_offset = bdrv_co_getlength(bs->file->bs);
467 if ((int64_t) cluster_offset < 0) {
468 return cluster_offset;
471 /* round to cluster size */
472 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
473 if (cluster_offset + s->cluster_size > INT64_MAX) {
476 ret = bdrv_co_truncate(bs->file,
477 cluster_offset + s->cluster_size,
478 false, PREALLOC_MODE_OFF, 0, NULL);
482 /* if encrypted, we must initialize the cluster
483 content which won't be written */
485 (n_end - n_start) < s->cluster_size) {
486 uint64_t start_offset;
488 start_offset = offset & ~(s->cluster_size - 1);
489 for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) {
490 if (i < n_start || i >= n_end) {
491 memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE);
492 if (qcrypto_block_encrypt(s->crypto,
499 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
500 ret = bdrv_co_pwrite(bs->file, cluster_offset + i,
509 } else if (allocate == 2) {
510 cluster_offset |= QCOW_OFLAG_COMPRESSED |
511 (uint64_t)compressed_size << (63 - s->cluster_bits);
514 /* update L2 table */
515 tmp = cpu_to_be64(cluster_offset);
516 l2_table[l2_index] = tmp;
518 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
520 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE);
522 ret = bdrv_co_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
523 sizeof(tmp), &tmp, 0);
528 *result = cluster_offset;
532 static int coroutine_fn GRAPH_RDLOCK
533 qcow_co_block_status(BlockDriverState *bs, bool want_zero,
534 int64_t offset, int64_t bytes, int64_t *pnum,
535 int64_t *map, BlockDriverState **file)
537 BDRVQcowState *s = bs->opaque;
538 int index_in_cluster, ret;
540 uint64_t cluster_offset;
542 qemu_co_mutex_lock(&s->lock);
543 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
544 qemu_co_mutex_unlock(&s->lock);
548 index_in_cluster = offset & (s->cluster_size - 1);
549 n = s->cluster_size - index_in_cluster;
554 if (!cluster_offset) {
557 if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
558 return BDRV_BLOCK_DATA | BDRV_BLOCK_COMPRESSED;
561 return BDRV_BLOCK_DATA;
563 *map = cluster_offset | index_in_cluster;
564 *file = bs->file->bs;
565 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
568 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
569 const uint8_t *buf, int buf_size)
571 z_stream strm1, *strm = &strm1;
574 memset(strm, 0, sizeof(*strm));
576 strm->next_in = (uint8_t *)buf;
577 strm->avail_in = buf_size;
578 strm->next_out = out_buf;
579 strm->avail_out = out_buf_size;
581 ret = inflateInit2(strm, -12);
584 ret = inflate(strm, Z_FINISH);
585 out_len = strm->next_out - out_buf;
586 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
587 out_len != out_buf_size) {
595 static int coroutine_fn GRAPH_RDLOCK
596 decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
598 BDRVQcowState *s = bs->opaque;
602 coffset = cluster_offset & s->cluster_offset_mask;
603 if (s->cluster_cache_offset != coffset) {
604 csize = cluster_offset >> (63 - s->cluster_bits);
605 csize &= (s->cluster_size - 1);
606 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
607 ret = bdrv_co_pread(bs->file, coffset, csize, s->cluster_data, 0);
610 if (decompress_buffer(s->cluster_cache, s->cluster_size,
611 s->cluster_data, csize) < 0) {
614 s->cluster_cache_offset = coffset;
619 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp)
621 /* At least encrypted images require 512-byte alignment. Apply the
622 * limit universally, rather than just on encrypted images, as
623 * it's easier to let the block layer handle rounding than to
624 * audit this code further. */
625 bs->bl.request_alignment = BDRV_SECTOR_SIZE;
628 static int coroutine_fn GRAPH_RDLOCK
629 qcow_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
630 QEMUIOVector *qiov, BdrvRequestFlags flags)
632 BDRVQcowState *s = bs->opaque;
633 int offset_in_cluster;
635 uint64_t cluster_offset;
639 if (qiov->niov > 1) {
640 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
646 buf = (uint8_t *)qiov->iov->iov_base;
649 qemu_co_mutex_lock(&s->lock);
652 /* prepare next request */
653 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
657 offset_in_cluster = offset & (s->cluster_size - 1);
658 n = s->cluster_size - offset_in_cluster;
663 if (!cluster_offset) {
665 /* read from the base image */
666 qemu_co_mutex_unlock(&s->lock);
667 /* qcow2 emits this on bs->file instead of bs->backing */
668 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
669 ret = bdrv_co_pread(bs->backing, offset, n, buf, 0);
670 qemu_co_mutex_lock(&s->lock);
675 /* Note: in this case, no need to wait */
678 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
679 /* add AIO support for compressed blocks ? */
680 if (decompress_cluster(bs, cluster_offset) < 0) {
684 memcpy(buf, s->cluster_cache + offset_in_cluster, n);
686 if ((cluster_offset & 511) != 0) {
690 qemu_co_mutex_unlock(&s->lock);
691 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_AIO);
692 ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster,
694 qemu_co_mutex_lock(&s->lock);
700 if (qcrypto_block_decrypt(s->crypto,
701 offset, buf, n, NULL) < 0) {
714 qemu_co_mutex_unlock(&s->lock);
716 if (qiov->niov > 1) {
717 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
718 qemu_vfree(orig_buf);
724 static int coroutine_fn GRAPH_RDLOCK
725 qcow_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
726 QEMUIOVector *qiov, BdrvRequestFlags flags)
728 BDRVQcowState *s = bs->opaque;
729 int offset_in_cluster;
730 uint64_t cluster_offset;
735 s->cluster_cache_offset = -1; /* disable compressed cache */
737 /* We must always copy the iov when encrypting, so we
738 * don't modify the original data buffer during encryption */
739 if (bs->encrypted || qiov->niov > 1) {
740 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
744 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
747 buf = (uint8_t *)qiov->iov->iov_base;
750 qemu_co_mutex_lock(&s->lock);
753 offset_in_cluster = offset & (s->cluster_size - 1);
754 n = s->cluster_size - offset_in_cluster;
758 ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster,
759 offset_in_cluster + n, &cluster_offset);
763 if (!cluster_offset || (cluster_offset & 511) != 0) {
769 if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) {
775 qemu_co_mutex_unlock(&s->lock);
776 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
777 ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster,
779 qemu_co_mutex_lock(&s->lock);
789 qemu_co_mutex_unlock(&s->lock);
791 qemu_vfree(orig_buf);
796 static void qcow_close(BlockDriverState *bs)
798 BDRVQcowState *s = bs->opaque;
800 qcrypto_block_free(s->crypto);
803 qemu_vfree(s->l2_cache);
804 g_free(s->cluster_cache);
805 g_free(s->cluster_data);
807 migrate_del_blocker(&s->migration_blocker);
810 static int coroutine_fn GRAPH_UNLOCKED
811 qcow_co_create(BlockdevCreateOptions *opts, Error **errp)
813 BlockdevCreateOptionsQcow *qcow_opts;
814 int header_size, backing_filename_len, l1_size, shift, i;
817 int64_t total_size = 0;
819 BlockDriverState *bs;
820 BlockBackend *qcow_blk;
821 QCryptoBlock *crypto = NULL;
823 assert(opts->driver == BLOCKDEV_DRIVER_QCOW);
824 qcow_opts = &opts->u.qcow;
827 total_size = qcow_opts->size;
828 if (total_size == 0) {
829 error_setg(errp, "Image size is too small, cannot be zero length");
833 if (qcow_opts->encrypt &&
834 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW)
836 error_setg(errp, "Unsupported encryption format");
840 /* Create BlockBackend to write to the image */
841 bs = bdrv_co_open_blockdev_ref(qcow_opts->file, errp);
846 qcow_blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE,
852 blk_set_allow_write_beyond_eof(qcow_blk, true);
854 /* Create image format */
855 memset(&header, 0, sizeof(header));
856 header.magic = cpu_to_be32(QCOW_MAGIC);
857 header.version = cpu_to_be32(QCOW_VERSION);
858 header.size = cpu_to_be64(total_size);
859 header_size = sizeof(header);
860 backing_filename_len = 0;
861 if (qcow_opts->backing_file) {
862 if (strcmp(qcow_opts->backing_file, "fat:")) {
863 header.backing_file_offset = cpu_to_be64(header_size);
864 backing_filename_len = strlen(qcow_opts->backing_file);
865 header.backing_file_size = cpu_to_be32(backing_filename_len);
866 header_size += backing_filename_len;
868 /* special backing file for vvfat */
869 qcow_opts->backing_file = NULL;
871 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
872 unmodified sectors */
873 header.l2_bits = 12; /* 32 KB L2 tables */
875 header.cluster_bits = 12; /* 4 KB clusters */
876 header.l2_bits = 9; /* 4 KB L2 tables */
878 header_size = (header_size + 7) & ~7;
879 shift = header.cluster_bits + header.l2_bits;
880 l1_size = (total_size + (1LL << shift) - 1) >> shift;
882 header.l1_table_offset = cpu_to_be64(header_size);
884 if (qcow_opts->encrypt) {
885 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
887 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.",
888 NULL, NULL, NULL, errp);
894 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
897 /* write all the data */
898 ret = blk_co_pwrite(qcow_blk, 0, sizeof(header), &header, 0);
903 if (qcow_opts->backing_file) {
904 ret = blk_co_pwrite(qcow_blk, sizeof(header), backing_filename_len,
905 qcow_opts->backing_file, 0);
911 tmp = g_malloc0(BDRV_SECTOR_SIZE);
912 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
914 ret = blk_co_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
915 BDRV_SECTOR_SIZE, tmp, 0);
925 blk_co_unref(qcow_blk);
927 qcrypto_block_free(crypto);
931 static int coroutine_fn GRAPH_UNLOCKED
932 qcow_co_create_opts(BlockDriver *drv, const char *filename,
933 QemuOpts *opts, Error **errp)
935 BlockdevCreateOptions *create_options = NULL;
936 BlockDriverState *bs = NULL;
943 static const QDictRenames opt_renames[] = {
944 { BLOCK_OPT_BACKING_FILE, "backing-file" },
945 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
950 * We can't actually store a backing format, but can check that
951 * the user's request made sense.
953 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
954 if (backing_fmt && !bdrv_find_format(backing_fmt)) {
955 error_setg(errp, "unrecognized backing format '%s'", backing_fmt);
960 /* Parse options and convert legacy syntax */
961 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);
963 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
964 if (val && !strcmp(val, "on")) {
965 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
966 } else if (val && !strcmp(val, "off")) {
967 qdict_del(qdict, BLOCK_OPT_ENCRYPT);
970 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
971 if (val && !strcmp(val, "aes")) {
972 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
975 if (!qdict_rename_keys(qdict, opt_renames, errp)) {
980 /* Create and open the file (protocol layer) */
981 ret = bdrv_co_create_file(filename, opts, errp);
986 bs = bdrv_co_open(filename, NULL, NULL,
987 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
993 /* Now get the QAPI type BlockdevCreateOptions */
994 qdict_put_str(qdict, "driver", "qcow");
995 qdict_put_str(qdict, "file", bs->node_name);
997 v = qobject_input_visitor_new_flat_confused(qdict, errp);
1003 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
1005 if (!create_options) {
1010 /* Silently round up size */
1011 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW);
1012 create_options->u.qcow.size =
1013 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE);
1015 /* Create the qcow image (format layer) */
1016 ret = qcow_co_create(create_options, errp);
1023 g_free(backing_fmt);
1024 qobject_unref(qdict);
1026 qapi_free_BlockdevCreateOptions(create_options);
1030 static int GRAPH_RDLOCK qcow_make_empty(BlockDriverState *bs)
1032 BDRVQcowState *s = bs->opaque;
1033 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1036 memset(s->l1_table, 0, l1_length);
1037 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, l1_length, s->l1_table,
1040 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, false,
1041 PREALLOC_MODE_OFF, 0, NULL);
1045 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
1046 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
1047 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
1052 /* XXX: put compressed sectors first, then all the cluster aligned
1053 tables to avoid losing bytes in alignment */
1054 static int coroutine_fn GRAPH_RDLOCK
1055 qcow_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes,
1058 BDRVQcowState *s = bs->opaque;
1061 uint8_t *buf, *out_buf;
1062 uint64_t cluster_offset;
1064 buf = qemu_blockalign(bs, s->cluster_size);
1065 if (bytes != s->cluster_size) {
1066 if (bytes > s->cluster_size ||
1067 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
1072 /* Zero-pad last write if image size is not cluster aligned */
1073 memset(buf + bytes, 0, s->cluster_size - bytes);
1075 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
1077 out_buf = g_malloc(s->cluster_size);
1079 /* best compression, small window, no zlib header */
1080 memset(&strm, 0, sizeof(strm));
1081 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1083 9, Z_DEFAULT_STRATEGY);
1089 strm.avail_in = s->cluster_size;
1090 strm.next_in = (uint8_t *)buf;
1091 strm.avail_out = s->cluster_size;
1092 strm.next_out = out_buf;
1094 ret = deflate(&strm, Z_FINISH);
1095 if (ret != Z_STREAM_END && ret != Z_OK) {
1100 out_len = strm.next_out - out_buf;
1104 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1105 /* could not compress: write normal cluster */
1106 ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0);
1112 qemu_co_mutex_lock(&s->lock);
1113 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
1114 qemu_co_mutex_unlock(&s->lock);
1118 if (cluster_offset == 0) {
1122 cluster_offset &= s->cluster_offset_mask;
1124 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1125 ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0);
1137 static int coroutine_fn
1138 qcow_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1140 BDRVQcowState *s = bs->opaque;
1141 bdi->cluster_size = s->cluster_size;
1145 static QemuOptsList qcow_create_opts = {
1146 .name = "qcow-create-opts",
1147 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1150 .name = BLOCK_OPT_SIZE,
1151 .type = QEMU_OPT_SIZE,
1152 .help = "Virtual disk size"
1155 .name = BLOCK_OPT_BACKING_FILE,
1156 .type = QEMU_OPT_STRING,
1157 .help = "File name of a base image"
1160 .name = BLOCK_OPT_BACKING_FMT,
1161 .type = QEMU_OPT_STRING,
1162 .help = "Format of the backing image",
1165 .name = BLOCK_OPT_ENCRYPT,
1166 .type = QEMU_OPT_BOOL,
1167 .help = "Encrypt the image with format 'aes'. (Deprecated "
1168 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
1171 .name = BLOCK_OPT_ENCRYPT_FORMAT,
1172 .type = QEMU_OPT_STRING,
1173 .help = "Encrypt the image, format choices: 'aes'",
1175 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1176 { /* end of list */ }
1180 static const char *const qcow_strong_runtime_opts[] = {
1181 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
1186 static BlockDriver bdrv_qcow = {
1187 .format_name = "qcow",
1188 .instance_size = sizeof(BDRVQcowState),
1189 .bdrv_probe = qcow_probe,
1190 .bdrv_open = qcow_open,
1191 .bdrv_close = qcow_close,
1192 .bdrv_child_perm = bdrv_default_perms,
1193 .bdrv_reopen_prepare = qcow_reopen_prepare,
1194 .bdrv_co_create = qcow_co_create,
1195 .bdrv_co_create_opts = qcow_co_create_opts,
1196 .bdrv_has_zero_init = bdrv_has_zero_init_1,
1198 .supports_backing = true,
1199 .bdrv_refresh_limits = qcow_refresh_limits,
1201 .bdrv_co_preadv = qcow_co_preadv,
1202 .bdrv_co_pwritev = qcow_co_pwritev,
1203 .bdrv_co_block_status = qcow_co_block_status,
1205 .bdrv_make_empty = qcow_make_empty,
1206 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
1207 .bdrv_co_get_info = qcow_co_get_info,
1209 .create_opts = &qcow_create_opts,
1210 .strong_runtime_opts = qcow_strong_runtime_opts,
1213 static void bdrv_qcow_init(void)
1215 bdrv_register(&bdrv_qcow);
1218 block_init(bdrv_qcow_init);