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 "block_int.h"
29 /**************************************************************/
30 /* QEMU COW block driver with compression and encryption support */
32 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
33 #define QCOW_VERSION 1
35 #define QCOW_CRYPT_NONE 0
36 #define QCOW_CRYPT_AES 1
38 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
40 typedef struct QCowHeader {
43 uint64_t backing_file_offset;
44 uint32_t backing_file_size;
46 uint64_t size; /* in bytes */
49 uint32_t crypt_method;
50 uint64_t l1_table_offset;
53 #define L2_CACHE_SIZE 16
55 typedef struct BDRVQcowState {
63 uint64_t cluster_offset_mask;
64 uint64_t l1_table_offset;
67 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
68 uint32_t l2_cache_counts[L2_CACHE_SIZE];
69 uint8_t *cluster_cache;
70 uint8_t *cluster_data;
71 uint64_t cluster_cache_offset;
72 uint32_t crypt_method; /* current crypt method, 0 if no key yet */
73 uint32_t crypt_method_header;
74 AES_KEY aes_encrypt_key;
75 AES_KEY aes_decrypt_key;
78 static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
80 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
82 const QCowHeader *cow_header = (const void *)buf;
84 if (buf_size >= sizeof(QCowHeader) &&
85 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
86 be32_to_cpu(cow_header->version) == QCOW_VERSION)
92 static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
94 BDRVQcowState *s = bs->opaque;
95 int len, i, shift, ret;
98 ret = bdrv_file_open(&s->hd, filename, flags);
101 if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
103 be32_to_cpus(&header.magic);
104 be32_to_cpus(&header.version);
105 be64_to_cpus(&header.backing_file_offset);
106 be32_to_cpus(&header.backing_file_size);
107 be32_to_cpus(&header.mtime);
108 be64_to_cpus(&header.size);
109 be32_to_cpus(&header.crypt_method);
110 be64_to_cpus(&header.l1_table_offset);
112 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
114 if (header.size <= 1 || header.cluster_bits < 9)
116 if (header.crypt_method > QCOW_CRYPT_AES)
118 s->crypt_method_header = header.crypt_method;
119 if (s->crypt_method_header)
121 s->cluster_bits = header.cluster_bits;
122 s->cluster_size = 1 << s->cluster_bits;
123 s->cluster_sectors = 1 << (s->cluster_bits - 9);
124 s->l2_bits = header.l2_bits;
125 s->l2_size = 1 << s->l2_bits;
126 bs->total_sectors = header.size / 512;
127 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
129 /* read the level 1 table */
130 shift = s->cluster_bits + s->l2_bits;
131 s->l1_size = (header.size + (1LL << shift) - 1) >> shift;
133 s->l1_table_offset = header.l1_table_offset;
134 s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
137 if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
138 s->l1_size * sizeof(uint64_t))
140 for(i = 0;i < s->l1_size; i++) {
141 be64_to_cpus(&s->l1_table[i]);
144 s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
147 s->cluster_cache = qemu_malloc(s->cluster_size);
148 if (!s->cluster_cache)
150 s->cluster_data = qemu_malloc(s->cluster_size);
151 if (!s->cluster_data)
153 s->cluster_cache_offset = -1;
155 /* read the backing file name */
156 if (header.backing_file_offset != 0) {
157 len = header.backing_file_size;
160 if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
162 bs->backing_file[len] = '\0';
167 qemu_free(s->l1_table);
168 qemu_free(s->l2_cache);
169 qemu_free(s->cluster_cache);
170 qemu_free(s->cluster_data);
175 static int qcow_set_key(BlockDriverState *bs, const char *key)
177 BDRVQcowState *s = bs->opaque;
181 memset(keybuf, 0, 16);
185 /* XXX: we could compress the chars to 7 bits to increase
187 for(i = 0;i < len;i++) {
190 s->crypt_method = s->crypt_method_header;
192 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
194 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
204 AES_encrypt(in, tmp, &s->aes_encrypt_key);
205 AES_decrypt(tmp, out, &s->aes_decrypt_key);
206 for(i = 0; i < 16; i++)
207 printf(" %02x", tmp[i]);
209 for(i = 0; i < 16; i++)
210 printf(" %02x", out[i]);
217 /* The crypt function is compatible with the linux cryptoloop
218 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
220 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
221 uint8_t *out_buf, const uint8_t *in_buf,
222 int nb_sectors, int enc,
231 for(i = 0; i < nb_sectors; i++) {
232 ivec.ll[0] = cpu_to_le64(sector_num);
234 AES_cbc_encrypt(in_buf, out_buf, 512, key,
246 * 1 to allocate a normal cluster (for sector indexes 'n_start' to
249 * 2 to allocate a compressed cluster of size
250 * 'compressed_size'. 'compressed_size' must be > 0 and <
253 * return 0 if not allocated.
255 static uint64_t get_cluster_offset(BlockDriverState *bs,
256 uint64_t offset, int allocate,
258 int n_start, int n_end)
260 BDRVQcowState *s = bs->opaque;
261 int min_index, i, j, l1_index, l2_index;
262 uint64_t l2_offset, *l2_table, cluster_offset, tmp;
266 l1_index = offset >> (s->l2_bits + s->cluster_bits);
267 l2_offset = s->l1_table[l1_index];
272 /* allocate a new l2 entry */
273 l2_offset = bdrv_getlength(s->hd);
274 /* round to cluster size */
275 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
276 /* update the L1 entry */
277 s->l1_table[l1_index] = l2_offset;
278 tmp = cpu_to_be64(l2_offset);
279 if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
280 &tmp, sizeof(tmp)) != sizeof(tmp))
284 for(i = 0; i < L2_CACHE_SIZE; i++) {
285 if (l2_offset == s->l2_cache_offsets[i]) {
286 /* increment the hit count */
287 if (++s->l2_cache_counts[i] == 0xffffffff) {
288 for(j = 0; j < L2_CACHE_SIZE; j++) {
289 s->l2_cache_counts[j] >>= 1;
292 l2_table = s->l2_cache + (i << s->l2_bits);
296 /* not found: load a new entry in the least used one */
298 min_count = 0xffffffff;
299 for(i = 0; i < L2_CACHE_SIZE; i++) {
300 if (s->l2_cache_counts[i] < min_count) {
301 min_count = s->l2_cache_counts[i];
305 l2_table = s->l2_cache + (min_index << s->l2_bits);
307 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
308 if (bdrv_pwrite(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
309 s->l2_size * sizeof(uint64_t))
312 if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
313 s->l2_size * sizeof(uint64_t))
316 s->l2_cache_offsets[min_index] = l2_offset;
317 s->l2_cache_counts[min_index] = 1;
319 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
320 cluster_offset = be64_to_cpu(l2_table[l2_index]);
321 if (!cluster_offset ||
322 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
325 /* allocate a new cluster */
326 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
327 (n_end - n_start) < s->cluster_sectors) {
328 /* if the cluster is already compressed, we must
329 decompress it in the case it is not completely
331 if (decompress_cluster(s, cluster_offset) < 0)
333 cluster_offset = bdrv_getlength(s->hd);
334 cluster_offset = (cluster_offset + s->cluster_size - 1) &
335 ~(s->cluster_size - 1);
336 /* write the cluster content */
337 if (bdrv_pwrite(s->hd, cluster_offset, s->cluster_cache, s->cluster_size) !=
341 cluster_offset = bdrv_getlength(s->hd);
343 /* round to cluster size */
344 cluster_offset = (cluster_offset + s->cluster_size - 1) &
345 ~(s->cluster_size - 1);
346 bdrv_truncate(s->hd, cluster_offset + s->cluster_size);
347 /* if encrypted, we must initialize the cluster
348 content which won't be written */
349 if (s->crypt_method &&
350 (n_end - n_start) < s->cluster_sectors) {
352 start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
353 memset(s->cluster_data + 512, 0xaa, 512);
354 for(i = 0; i < s->cluster_sectors; i++) {
355 if (i < n_start || i >= n_end) {
356 encrypt_sectors(s, start_sect + i,
358 s->cluster_data + 512, 1, 1,
359 &s->aes_encrypt_key);
360 if (bdrv_pwrite(s->hd, cluster_offset + i * 512,
361 s->cluster_data, 512) != 512)
367 cluster_offset |= QCOW_OFLAG_COMPRESSED |
368 (uint64_t)compressed_size << (63 - s->cluster_bits);
371 /* update L2 table */
372 tmp = cpu_to_be64(cluster_offset);
373 l2_table[l2_index] = tmp;
374 if (bdrv_pwrite(s->hd,
375 l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
378 return cluster_offset;
381 static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
382 int nb_sectors, int *pnum)
384 BDRVQcowState *s = bs->opaque;
385 int index_in_cluster, n;
386 uint64_t cluster_offset;
388 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
389 index_in_cluster = sector_num & (s->cluster_sectors - 1);
390 n = s->cluster_sectors - index_in_cluster;
394 return (cluster_offset != 0);
397 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
398 const uint8_t *buf, int buf_size)
400 z_stream strm1, *strm = &strm1;
403 memset(strm, 0, sizeof(*strm));
405 strm->next_in = (uint8_t *)buf;
406 strm->avail_in = buf_size;
407 strm->next_out = out_buf;
408 strm->avail_out = out_buf_size;
410 ret = inflateInit2(strm, -12);
413 ret = inflate(strm, Z_FINISH);
414 out_len = strm->next_out - out_buf;
415 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
416 out_len != out_buf_size) {
424 static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
429 coffset = cluster_offset & s->cluster_offset_mask;
430 if (s->cluster_cache_offset != coffset) {
431 csize = cluster_offset >> (63 - s->cluster_bits);
432 csize &= (s->cluster_size - 1);
433 ret = bdrv_pread(s->hd, coffset, s->cluster_data, csize);
436 if (decompress_buffer(s->cluster_cache, s->cluster_size,
437 s->cluster_data, csize) < 0) {
440 s->cluster_cache_offset = coffset;
447 static int qcow_read(BlockDriverState *bs, int64_t sector_num,
448 uint8_t *buf, int nb_sectors)
450 BDRVQcowState *s = bs->opaque;
451 int ret, index_in_cluster, n;
452 uint64_t cluster_offset;
454 while (nb_sectors > 0) {
455 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
456 index_in_cluster = sector_num & (s->cluster_sectors - 1);
457 n = s->cluster_sectors - index_in_cluster;
460 if (!cluster_offset) {
461 if (bs->backing_hd) {
462 /* read from the base image */
463 ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
467 memset(buf, 0, 512 * n);
469 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
470 if (decompress_cluster(s, cluster_offset) < 0)
472 memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
474 ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
477 if (s->crypt_method) {
478 encrypt_sectors(s, sector_num, buf, buf, n, 0,
479 &s->aes_decrypt_key);
490 static int qcow_write(BlockDriverState *bs, int64_t sector_num,
491 const uint8_t *buf, int nb_sectors)
493 BDRVQcowState *s = bs->opaque;
494 int ret, index_in_cluster, n;
495 uint64_t cluster_offset;
497 while (nb_sectors > 0) {
498 index_in_cluster = sector_num & (s->cluster_sectors - 1);
499 n = s->cluster_sectors - index_in_cluster;
502 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
504 index_in_cluster + n);
507 if (s->crypt_method) {
508 encrypt_sectors(s, sector_num, s->cluster_data, buf, n, 1,
509 &s->aes_encrypt_key);
510 ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512,
511 s->cluster_data, n * 512);
513 ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
521 s->cluster_cache_offset = -1; /* disable compressed cache */
530 uint64_t cluster_offset;
531 uint8_t *cluster_data;
532 BlockDriverAIOCB *hd_aiocb;
533 BlockDriverAIOCB *backing_hd_aiocb;
536 static void qcow_aio_delete(BlockDriverAIOCB *acb);
538 static int qcow_aio_new(BlockDriverAIOCB *acb)
540 BlockDriverState *bs = acb->bs;
541 BDRVQcowState *s = bs->opaque;
543 acb1 = qemu_mallocz(sizeof(QCowAIOCB));
547 acb1->hd_aiocb = bdrv_aio_new(s->hd);
550 if (bs->backing_hd) {
551 acb1->backing_hd_aiocb = bdrv_aio_new(bs->backing_hd);
552 if (!acb1->backing_hd_aiocb)
557 qcow_aio_delete(acb);
561 static void qcow_aio_read_cb(void *opaque, int ret)
563 BlockDriverAIOCB *acb = opaque;
564 BlockDriverState *bs = acb->bs;
565 BDRVQcowState *s = bs->opaque;
566 QCowAIOCB *acb1 = acb->opaque;
567 int index_in_cluster;
571 acb->cb(acb->cb_opaque, ret);
576 /* post process the read buffer */
577 if (!acb1->cluster_offset) {
579 } else if (acb1->cluster_offset & QCOW_OFLAG_COMPRESSED) {
582 if (s->crypt_method) {
583 encrypt_sectors(s, acb1->sector_num, acb1->buf, acb1->buf,
585 &s->aes_decrypt_key);
589 acb1->nb_sectors -= acb1->n;
590 acb1->sector_num += acb1->n;
591 acb1->buf += acb1->n * 512;
593 if (acb1->nb_sectors == 0) {
594 /* request completed */
595 acb->cb(acb->cb_opaque, 0);
599 /* prepare next AIO request */
600 acb1->cluster_offset = get_cluster_offset(bs,
601 acb1->sector_num << 9,
603 index_in_cluster = acb1->sector_num & (s->cluster_sectors - 1);
604 acb1->n = s->cluster_sectors - index_in_cluster;
605 if (acb1->n > acb1->nb_sectors)
606 acb1->n = acb1->nb_sectors;
608 if (!acb1->cluster_offset) {
609 if (bs->backing_hd) {
610 /* read from the base image */
611 ret = bdrv_aio_read(acb1->backing_hd_aiocb, acb1->sector_num,
612 acb1->buf, acb1->n, qcow_aio_read_cb, acb);
616 /* Note: in this case, no need to wait */
617 memset(acb1->buf, 0, 512 * acb1->n);
620 } else if (acb1->cluster_offset & QCOW_OFLAG_COMPRESSED) {
621 /* add AIO support for compressed blocks ? */
622 if (decompress_cluster(s, acb1->cluster_offset) < 0)
625 s->cluster_cache + index_in_cluster * 512, 512 * acb1->n);
628 if ((acb1->cluster_offset & 511) != 0) {
632 ret = bdrv_aio_read(acb1->hd_aiocb,
633 (acb1->cluster_offset >> 9) + index_in_cluster,
634 acb1->buf, acb1->n, qcow_aio_read_cb, acb);
640 static int qcow_aio_read(BlockDriverAIOCB *acb, int64_t sector_num,
641 uint8_t *buf, int nb_sectors)
643 QCowAIOCB *acb1 = acb->opaque;
645 acb1->sector_num = sector_num;
647 acb1->nb_sectors = nb_sectors;
649 acb1->cluster_offset = 0;
651 qcow_aio_read_cb(acb, 0);
655 static void qcow_aio_write_cb(void *opaque, int ret)
657 BlockDriverAIOCB *acb = opaque;
658 BlockDriverState *bs = acb->bs;
659 BDRVQcowState *s = bs->opaque;
660 QCowAIOCB *acb1 = acb->opaque;
661 int index_in_cluster;
662 uint64_t cluster_offset;
663 const uint8_t *src_buf;
667 acb->cb(acb->cb_opaque, ret);
671 acb1->nb_sectors -= acb1->n;
672 acb1->sector_num += acb1->n;
673 acb1->buf += acb1->n * 512;
675 if (acb1->nb_sectors == 0) {
676 /* request completed */
677 acb->cb(acb->cb_opaque, 0);
681 index_in_cluster = acb1->sector_num & (s->cluster_sectors - 1);
682 acb1->n = s->cluster_sectors - index_in_cluster;
683 if (acb1->n > acb1->nb_sectors)
684 acb1->n = acb1->nb_sectors;
685 cluster_offset = get_cluster_offset(bs, acb1->sector_num << 9, 1, 0,
687 index_in_cluster + acb1->n);
688 if (!cluster_offset || (cluster_offset & 511) != 0) {
692 if (s->crypt_method) {
693 if (!acb1->cluster_data) {
694 acb1->cluster_data = qemu_mallocz(s->cluster_size);
695 if (!acb1->cluster_data) {
700 encrypt_sectors(s, acb1->sector_num, acb1->cluster_data, acb1->buf,
701 acb1->n, 1, &s->aes_encrypt_key);
702 src_buf = acb1->cluster_data;
706 ret = bdrv_aio_write(acb1->hd_aiocb,
707 (cluster_offset >> 9) + index_in_cluster,
709 qcow_aio_write_cb, acb);
714 static int qcow_aio_write(BlockDriverAIOCB *acb, int64_t sector_num,
715 const uint8_t *buf, int nb_sectors)
717 QCowAIOCB *acb1 = acb->opaque;
718 BlockDriverState *bs = acb->bs;
719 BDRVQcowState *s = bs->opaque;
721 s->cluster_cache_offset = -1; /* disable compressed cache */
723 acb1->sector_num = sector_num;
724 acb1->buf = (uint8_t *)buf;
725 acb1->nb_sectors = nb_sectors;
728 qcow_aio_write_cb(acb, 0);
732 static void qcow_aio_cancel(BlockDriverAIOCB *acb)
734 QCowAIOCB *acb1 = acb->opaque;
736 bdrv_aio_cancel(acb1->hd_aiocb);
737 if (acb1->backing_hd_aiocb)
738 bdrv_aio_cancel(acb1->backing_hd_aiocb);
741 static void qcow_aio_delete(BlockDriverAIOCB *acb)
743 QCowAIOCB *acb1 = acb->opaque;
745 bdrv_aio_delete(acb1->hd_aiocb);
746 if (acb1->backing_hd_aiocb)
747 bdrv_aio_delete(acb1->backing_hd_aiocb);
748 qemu_free(acb1->cluster_data);
752 static void qcow_close(BlockDriverState *bs)
754 BDRVQcowState *s = bs->opaque;
755 qemu_free(s->l1_table);
756 qemu_free(s->l2_cache);
757 qemu_free(s->cluster_cache);
758 qemu_free(s->cluster_data);
762 static int qcow_create(const char *filename, int64_t total_size,
763 const char *backing_file, int flags)
765 int fd, header_size, backing_filename_len, l1_size, i, shift;
769 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
772 memset(&header, 0, sizeof(header));
773 header.magic = cpu_to_be32(QCOW_MAGIC);
774 header.version = cpu_to_be32(QCOW_VERSION);
775 header.size = cpu_to_be64(total_size * 512);
776 header_size = sizeof(header);
777 backing_filename_len = 0;
779 header.backing_file_offset = cpu_to_be64(header_size);
780 backing_filename_len = strlen(backing_file);
781 header.backing_file_size = cpu_to_be32(backing_filename_len);
782 header_size += backing_filename_len;
783 header.mtime = cpu_to_be32(0);
784 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
785 unmodifyed sectors */
786 header.l2_bits = 12; /* 32 KB L2 tables */
788 header.cluster_bits = 12; /* 4 KB clusters */
789 header.l2_bits = 9; /* 4 KB L2 tables */
791 header_size = (header_size + 7) & ~7;
792 shift = header.cluster_bits + header.l2_bits;
793 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift;
795 header.l1_table_offset = cpu_to_be64(header_size);
797 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
799 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
802 /* write all the data */
803 write(fd, &header, sizeof(header));
805 write(fd, backing_file, backing_filename_len);
807 lseek(fd, header_size, SEEK_SET);
809 for(i = 0;i < l1_size; i++) {
810 write(fd, &tmp, sizeof(tmp));
816 int qcow_make_empty(BlockDriverState *bs)
818 BDRVQcowState *s = bs->opaque;
819 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
822 memset(s->l1_table, 0, l1_length);
823 if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
825 ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
829 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
830 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
831 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
836 int qcow_get_cluster_size(BlockDriverState *bs)
838 BDRVQcowState *s = bs->opaque;
839 if (bs->drv != &bdrv_qcow)
841 return s->cluster_size;
844 /* XXX: put compressed sectors first, then all the cluster aligned
845 tables to avoid losing bytes in alignment */
846 int qcow_compress_cluster(BlockDriverState *bs, int64_t sector_num,
849 BDRVQcowState *s = bs->opaque;
853 uint64_t cluster_offset;
855 if (bs->drv != &bdrv_qcow)
858 out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
862 /* best compression, small window, no zlib header */
863 memset(&strm, 0, sizeof(strm));
864 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
866 9, Z_DEFAULT_STRATEGY);
872 strm.avail_in = s->cluster_size;
873 strm.next_in = (uint8_t *)buf;
874 strm.avail_out = s->cluster_size;
875 strm.next_out = out_buf;
877 ret = deflate(&strm, Z_FINISH);
878 if (ret != Z_STREAM_END && ret != Z_OK) {
883 out_len = strm.next_out - out_buf;
887 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
888 /* could not compress: write normal cluster */
889 qcow_write(bs, sector_num, buf, s->cluster_sectors);
891 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
893 cluster_offset &= s->cluster_offset_mask;
894 if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
904 static void qcow_flush(BlockDriverState *bs)
906 BDRVQcowState *s = bs->opaque;
910 BlockDriver bdrv_qcow = {
912 sizeof(BDRVQcowState),
924 .bdrv_aio_new = qcow_aio_new,
925 .bdrv_aio_read = qcow_aio_read,
926 .bdrv_aio_write = qcow_aio_write,
927 .bdrv_aio_cancel = qcow_aio_cancel,
928 .bdrv_aio_delete = qcow_aio_delete,