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4899d10d14
qemu/block/qcow.c
Kevin Wolf 66f82ceed6 block: Open the underlying image file in generic code 
Format drivers shouldn't need to bother with things like file names, but rather
just get an open BlockDriverState for the underlying protocol. This patch
introduces this behaviour for bdrv_open implementation. For protocols which
need to access the filename to open their file/device/connection/... a new
callback bdrv_file_open is introduced which doesn't get an underlying file
opened.

For now, also some of the more obscure formats use bdrv_file_open because they
open() the file themselves instead of using the block.c functions. They need to
be fixed in later patches.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03 10:07:30 +02:00

975 lines
30 KiB
C
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/*
* Block driver for the QCOW format
*
* Copyright (c) 2004-2006 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu-common.h"
#include "block_int.h"
#include "module.h"
#include <zlib.h>
#include "aes.h"
/**************************************************************/
/* QEMU COW block driver with compression and encryption support */
#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
#define QCOW_VERSION 1
#define QCOW_CRYPT_NONE 0
#define QCOW_CRYPT_AES 1
#define QCOW_OFLAG_COMPRESSED (1LL << 63)
typedef struct QCowHeader {
uint32_t magic;
uint32_t version;
uint64_t backing_file_offset;
uint32_t backing_file_size;
uint32_t mtime;
uint64_t size; /* in bytes */
uint8_t cluster_bits;
uint8_t l2_bits;
uint32_t crypt_method;
uint64_t l1_table_offset;
} QCowHeader;
#define L2_CACHE_SIZE 16
typedef struct BDRVQcowState {
BlockDriverState *hd;
int cluster_bits;
int cluster_size;
int cluster_sectors;
int l2_bits;
int l2_size;
int l1_size;
uint64_t cluster_offset_mask;
uint64_t l1_table_offset;
uint64_t *l1_table;
uint64_t *l2_cache;
uint64_t l2_cache_offsets[L2_CACHE_SIZE];
uint32_t l2_cache_counts[L2_CACHE_SIZE];
uint8_t *cluster_cache;
uint8_t *cluster_data;
uint64_t cluster_cache_offset;
uint32_t crypt_method; /* current crypt method, 0 if no key yet */
uint32_t crypt_method_header;
AES_KEY aes_encrypt_key;
AES_KEY aes_decrypt_key;
} BDRVQcowState;
static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
{
const QCowHeader *cow_header = (const void *)buf;
if (buf_size >= sizeof(QCowHeader) &&
be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
be32_to_cpu(cow_header->version) == QCOW_VERSION)
return 100;
else
return 0;
}
static int qcow_open(BlockDriverState *bs, int flags)
{
BDRVQcowState *s = bs->opaque;
int len, i, shift;
QCowHeader header;
if (bdrv_pread(bs->file, 0, &header, sizeof(header)) != sizeof(header))
goto fail;
be32_to_cpus(&header.magic);
be32_to_cpus(&header.version);
be64_to_cpus(&header.backing_file_offset);
be32_to_cpus(&header.backing_file_size);
be32_to_cpus(&header.mtime);
be64_to_cpus(&header.size);
be32_to_cpus(&header.crypt_method);
be64_to_cpus(&header.l1_table_offset);
if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
goto fail;
if (header.size <= 1 || header.cluster_bits < 9)
goto fail;
if (header.crypt_method > QCOW_CRYPT_AES)
goto fail;
s->crypt_method_header = header.crypt_method;
if (s->crypt_method_header)
bs->encrypted = 1;
s->cluster_bits = header.cluster_bits;
s->cluster_size = 1 << s->cluster_bits;
s->cluster_sectors = 1 << (s->cluster_bits - 9);
s->l2_bits = header.l2_bits;
s->l2_size = 1 << s->l2_bits;
bs->total_sectors = header.size / 512;
s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
/* read the level 1 table */
shift = s->cluster_bits + s->l2_bits;
s->l1_size = (header.size + (1LL << shift) - 1) >> shift;
s->l1_table_offset = header.l1_table_offset;
s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
if (!s->l1_table)
goto fail;
if (bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
s->l1_size * sizeof(uint64_t))
goto fail;
for(i = 0;i < s->l1_size; i++) {
be64_to_cpus(&s->l1_table[i]);
}
/* alloc L2 cache */
s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
if (!s->l2_cache)
goto fail;
s->cluster_cache = qemu_malloc(s->cluster_size);
if (!s->cluster_cache)
goto fail;
s->cluster_data = qemu_malloc(s->cluster_size);
if (!s->cluster_data)
goto fail;
s->cluster_cache_offset = -1;
/* read the backing file name */
if (header.backing_file_offset != 0) {
len = header.backing_file_size;
if (len > 1023)
len = 1023;
if (bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len) != len)
goto fail;
bs->backing_file[len] = '\0';
}
return 0;
fail:
qemu_free(s->l1_table);
qemu_free(s->l2_cache);
qemu_free(s->cluster_cache);
qemu_free(s->cluster_data);
return -1;
}
static int qcow_set_key(BlockDriverState *bs, const char *key)
{
BDRVQcowState *s = bs->opaque;
uint8_t keybuf[16];
int len, i;
memset(keybuf, 0, 16);
len = strlen(key);
if (len > 16)
len = 16;
/* XXX: we could compress the chars to 7 bits to increase
entropy */
for(i = 0;i < len;i++) {
keybuf[i] = key[i];
}
s->crypt_method = s->crypt_method_header;
if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
return -1;
if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
return -1;
#if 0
/* test */
{
uint8_t in[16];
uint8_t out[16];
uint8_t tmp[16];
for(i=0;i<16;i++)
in[i] = i;
AES_encrypt(in, tmp, &s->aes_encrypt_key);
AES_decrypt(tmp, out, &s->aes_decrypt_key);
for(i = 0; i < 16; i++)
printf(" %02x", tmp[i]);
printf("\n");
for(i = 0; i < 16; i++)
printf(" %02x", out[i]);
printf("\n");
}
#endif
return 0;
}
/* The crypt function is compatible with the linux cryptoloop
algorithm for < 4 GB images. NOTE: out_buf == in_buf is
supported */
static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
uint8_t *out_buf, const uint8_t *in_buf,
int nb_sectors, int enc,
const AES_KEY *key)
{
union {
uint64_t ll[2];
uint8_t b[16];
} ivec;
int i;
for(i = 0; i < nb_sectors; i++) {
ivec.ll[0] = cpu_to_le64(sector_num);
ivec.ll[1] = 0;
AES_cbc_encrypt(in_buf, out_buf, 512, key,
ivec.b, enc);
sector_num++;
in_buf += 512;
out_buf += 512;
}
}
/* 'allocate' is:
*
* 0 to not allocate.
*
* 1 to allocate a normal cluster (for sector indexes 'n_start' to
* 'n_end')
*
* 2 to allocate a compressed cluster of size
* 'compressed_size'. 'compressed_size' must be > 0 and <
* cluster_size
*
* return 0 if not allocated.
*/
static uint64_t get_cluster_offset(BlockDriverState *bs,
uint64_t offset, int allocate,
int compressed_size,
int n_start, int n_end)
{
BDRVQcowState *s = bs->opaque;
int min_index, i, j, l1_index, l2_index;
uint64_t l2_offset, *l2_table, cluster_offset, tmp;
uint32_t min_count;
int new_l2_table;
l1_index = offset >> (s->l2_bits + s->cluster_bits);
l2_offset = s->l1_table[l1_index];
new_l2_table = 0;
if (!l2_offset) {
if (!allocate)
return 0;
/* allocate a new l2 entry */
l2_offset = bdrv_getlength(bs->file);
/* round to cluster size */
l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
/* update the L1 entry */
s->l1_table[l1_index] = l2_offset;
tmp = cpu_to_be64(l2_offset);
if (bdrv_pwrite(bs->file, s->l1_table_offset + l1_index * sizeof(tmp),
&tmp, sizeof(tmp)) != sizeof(tmp))
return 0;
new_l2_table = 1;
}
for(i = 0; i < L2_CACHE_SIZE; i++) {
if (l2_offset == s->l2_cache_offsets[i]) {
/* increment the hit count */
if (++s->l2_cache_counts[i] == 0xffffffff) {
for(j = 0; j < L2_CACHE_SIZE; j++) {
s->l2_cache_counts[j] >>= 1;
}
}
l2_table = s->l2_cache + (i << s->l2_bits);
goto found;
}
}
/* not found: load a new entry in the least used one */
min_index = 0;
min_count = 0xffffffff;
for(i = 0; i < L2_CACHE_SIZE; i++) {
if (s->l2_cache_counts[i] < min_count) {
min_count = s->l2_cache_counts[i];
min_index = i;
}
}
l2_table = s->l2_cache + (min_index << s->l2_bits);
if (new_l2_table) {
memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
if (bdrv_pwrite(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
s->l2_size * sizeof(uint64_t))
return 0;
} else {
if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
s->l2_size * sizeof(uint64_t))
return 0;
}
s->l2_cache_offsets[min_index] = l2_offset;
s->l2_cache_counts[min_index] = 1;
found:
l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
cluster_offset = be64_to_cpu(l2_table[l2_index]);
if (!cluster_offset ||
((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
if (!allocate)
return 0;
/* allocate a new cluster */
if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
(n_end - n_start) < s->cluster_sectors) {
/* if the cluster is already compressed, we must
decompress it in the case it is not completely
overwritten */
if (decompress_cluster(bs, cluster_offset) < 0)
return 0;
cluster_offset = bdrv_getlength(bs->file);
cluster_offset = (cluster_offset + s->cluster_size - 1) &
~(s->cluster_size - 1);
/* write the cluster content */
if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) !=
s->cluster_size)
return -1;
} else {
cluster_offset = bdrv_getlength(bs->file);
if (allocate == 1) {
/* round to cluster size */
cluster_offset = (cluster_offset + s->cluster_size - 1) &
~(s->cluster_size - 1);
bdrv_truncate(bs->file, cluster_offset + s->cluster_size);
/* if encrypted, we must initialize the cluster
content which won't be written */
if (s->crypt_method &&
(n_end - n_start) < s->cluster_sectors) {
uint64_t start_sect;
start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
memset(s->cluster_data + 512, 0x00, 512);
for(i = 0; i < s->cluster_sectors; i++) {
if (i < n_start || i >= n_end) {
encrypt_sectors(s, start_sect + i,
s->cluster_data,
s->cluster_data + 512, 1, 1,
&s->aes_encrypt_key);
if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
s->cluster_data, 512) != 512)
return -1;
}
}
}
} else if (allocate == 2) {
cluster_offset |= QCOW_OFLAG_COMPRESSED |
(uint64_t)compressed_size << (63 - s->cluster_bits);
}
}
/* update L2 table */
tmp = cpu_to_be64(cluster_offset);
l2_table[l2_index] = tmp;
if (bdrv_pwrite(bs->file,
l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
return 0;
}
return cluster_offset;
}
static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum)
{
BDRVQcowState *s = bs->opaque;
int index_in_cluster, n;
uint64_t cluster_offset;
cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
index_in_cluster = sector_num & (s->cluster_sectors - 1);
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors)
n = nb_sectors;
*pnum = n;
return (cluster_offset != 0);
}
static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
const uint8_t *buf, int buf_size)
{
z_stream strm1, *strm = &strm1;
int ret, out_len;
memset(strm, 0, sizeof(*strm));
strm->next_in = (uint8_t *)buf;
strm->avail_in = buf_size;
strm->next_out = out_buf;
strm->avail_out = out_buf_size;
ret = inflateInit2(strm, -12);
if (ret != Z_OK)
return -1;
ret = inflate(strm, Z_FINISH);
out_len = strm->next_out - out_buf;
if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
out_len != out_buf_size) {
inflateEnd(strm);
return -1;
}
inflateEnd(strm);
return 0;
}
static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
{
BDRVQcowState *s = bs->opaque;
int ret, csize;
uint64_t coffset;
coffset = cluster_offset & s->cluster_offset_mask;
if (s->cluster_cache_offset != coffset) {
csize = cluster_offset >> (63 - s->cluster_bits);
csize &= (s->cluster_size - 1);
ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
if (ret != csize)
return -1;
if (decompress_buffer(s->cluster_cache, s->cluster_size,
s->cluster_data, csize) < 0) {
return -1;
}
s->cluster_cache_offset = coffset;
}
return 0;
}
#if 0
static int qcow_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
BDRVQcowState *s = bs->opaque;
int ret, index_in_cluster, n;
uint64_t cluster_offset;
while (nb_sectors > 0) {
cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
index_in_cluster = sector_num & (s->cluster_sectors - 1);
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors)
n = nb_sectors;
if (!cluster_offset) {
if (bs->backing_hd) {
/* read from the base image */
ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
if (ret < 0)
return -1;
} else {
memset(buf, 0, 512 * n);
}
} else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
if (decompress_cluster(bs, cluster_offset) < 0)
return -1;
memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
} else {
ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512);
if (ret != n * 512)
return -1;
if (s->crypt_method) {
encrypt_sectors(s, sector_num, buf, buf, n, 0,
&s->aes_decrypt_key);
}
}
nb_sectors -= n;
sector_num += n;
buf += n * 512;
}
return 0;
}
#endif
typedef struct QCowAIOCB {
BlockDriverAIOCB common;
int64_t sector_num;
QEMUIOVector *qiov;
uint8_t *buf;
void *orig_buf;
int nb_sectors;
int n;
uint64_t cluster_offset;
uint8_t *cluster_data;
struct iovec hd_iov;
QEMUIOVector hd_qiov;
BlockDriverAIOCB *hd_aiocb;
} QCowAIOCB;
static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
{
QCowAIOCB *acb = (QCowAIOCB *)blockacb;
if (acb->hd_aiocb)
bdrv_aio_cancel(acb->hd_aiocb);
qemu_aio_release(acb);
}
static AIOPool qcow_aio_pool = {
.aiocb_size = sizeof(QCowAIOCB),
.cancel = qcow_aio_cancel,
};
static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque, int is_write)
{
QCowAIOCB *acb;
acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
if (!acb)
return NULL;
acb->hd_aiocb = NULL;
acb->sector_num = sector_num;
acb->qiov = qiov;
if (qiov->niov > 1) {
acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size);
if (is_write)
qemu_iovec_to_buffer(qiov, acb->buf);
} else {
acb->buf = (uint8_t *)qiov->iov->iov_base;
}
acb->nb_sectors = nb_sectors;
acb->n = 0;
acb->cluster_offset = 0;
return acb;
}
static void qcow_aio_read_cb(void *opaque, int ret)
{
QCowAIOCB *acb = opaque;
BlockDriverState *bs = acb->common.bs;
BDRVQcowState *s = bs->opaque;
int index_in_cluster;
acb->hd_aiocb = NULL;
if (ret < 0)
goto done;
redo:
/* post process the read buffer */
if (!acb->cluster_offset) {
/* nothing to do */
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
/* nothing to do */
} else {
if (s->crypt_method) {
encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
acb->n, 0,
&s->aes_decrypt_key);
}
}
acb->nb_sectors -= acb->n;
acb->sector_num += acb->n;
acb->buf += acb->n * 512;
if (acb->nb_sectors == 0) {
/* request completed */
ret = 0;
goto done;
}
/* prepare next AIO request */
acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9,
0, 0, 0, 0);
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
acb->n = s->cluster_sectors - index_in_cluster;
if (acb->n > acb->nb_sectors)
acb->n = acb->nb_sectors;
if (!acb->cluster_offset) {
if (bs->backing_hd) {
/* read from the base image */
acb->hd_iov.iov_base = (void *)acb->buf;
acb->hd_iov.iov_len = acb->n * 512;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
&acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
if (acb->hd_aiocb == NULL)
goto done;
} else {
/* Note: in this case, no need to wait */
memset(acb->buf, 0, 512 * acb->n);
goto redo;
}
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
/* add AIO support for compressed blocks ? */
if (decompress_cluster(bs, acb->cluster_offset) < 0)
goto done;
memcpy(acb->buf,
s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
goto redo;
} else {
if ((acb->cluster_offset & 511) != 0) {
ret = -EIO;
goto done;
}
acb->hd_iov.iov_base = (void *)acb->buf;
acb->hd_iov.iov_len = acb->n * 512;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_readv(bs->file,
(acb->cluster_offset >> 9) + index_in_cluster,
&acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
if (acb->hd_aiocb == NULL)
goto done;
}
return;
done:
if (acb->qiov->niov > 1) {
qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
qemu_vfree(acb->orig_buf);
}
acb->common.cb(acb->common.opaque, ret);
qemu_aio_release(acb);
}
static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
{
QCowAIOCB *acb;
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
if (!acb)
return NULL;
qcow_aio_read_cb(acb, 0);
return &acb->common;
}
static void qcow_aio_write_cb(void *opaque, int ret)
{
QCowAIOCB *acb = opaque;
BlockDriverState *bs = acb->common.bs;
BDRVQcowState *s = bs->opaque;
int index_in_cluster;
uint64_t cluster_offset;
const uint8_t *src_buf;
acb->hd_aiocb = NULL;
if (ret < 0)
goto done;
acb->nb_sectors -= acb->n;
acb->sector_num += acb->n;
acb->buf += acb->n * 512;
if (acb->nb_sectors == 0) {
/* request completed */
ret = 0;
goto done;
}
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
acb->n = s->cluster_sectors - index_in_cluster;
if (acb->n > acb->nb_sectors)
acb->n = acb->nb_sectors;
cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
index_in_cluster,
index_in_cluster + acb->n);
if (!cluster_offset || (cluster_offset & 511) != 0) {
ret = -EIO;
goto done;
}
if (s->crypt_method) {
if (!acb->cluster_data) {
acb->cluster_data = qemu_mallocz(s->cluster_size);
if (!acb->cluster_data) {
ret = -ENOMEM;
goto done;
}
}
encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
acb->n, 1, &s->aes_encrypt_key);
src_buf = acb->cluster_data;
} else {
src_buf = acb->buf;
}
acb->hd_iov.iov_base = (void *)src_buf;
acb->hd_iov.iov_len = acb->n * 512;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_writev(bs->file,
(cluster_offset >> 9) + index_in_cluster,
&acb->hd_qiov, acb->n,
qcow_aio_write_cb, acb);
if (acb->hd_aiocb == NULL)
goto done;
return;
done:
if (acb->qiov->niov > 1)
qemu_vfree(acb->orig_buf);
acb->common.cb(acb->common.opaque, ret);
qemu_aio_release(acb);
}
static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
{
BDRVQcowState *s = bs->opaque;
QCowAIOCB *acb;
s->cluster_cache_offset = -1; /* disable compressed cache */
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
if (!acb)
return NULL;
qcow_aio_write_cb(acb, 0);
return &acb->common;
}
static void qcow_close(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
qemu_free(s->l1_table);
qemu_free(s->l2_cache);
qemu_free(s->cluster_cache);
qemu_free(s->cluster_data);
}
static int qcow_create(const char *filename, QEMUOptionParameter *options)
{
int fd, header_size, backing_filename_len, l1_size, i, shift;
QCowHeader header;
uint64_t tmp;
int64_t total_size = 0;
const char *backing_file = NULL;
int flags = 0;
int ret;
/* Read out options */
while (options && options->name) {
if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
total_size = options->value.n / 512;
} else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
backing_file = options->value.s;
} else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
}
options++;
}
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
if (fd < 0)
return -errno;
memset(&header, 0, sizeof(header));
header.magic = cpu_to_be32(QCOW_MAGIC);
header.version = cpu_to_be32(QCOW_VERSION);
header.size = cpu_to_be64(total_size * 512);
header_size = sizeof(header);
backing_filename_len = 0;
if (backing_file) {
if (strcmp(backing_file, "fat:")) {
header.backing_file_offset = cpu_to_be64(header_size);
backing_filename_len = strlen(backing_file);
header.backing_file_size = cpu_to_be32(backing_filename_len);
header_size += backing_filename_len;
} else {
/* special backing file for vvfat */
backing_file = NULL;
}
header.cluster_bits = 9; /* 512 byte cluster to avoid copying
unmodifyed sectors */
header.l2_bits = 12; /* 32 KB L2 tables */
} else {
header.cluster_bits = 12; /* 4 KB clusters */
header.l2_bits = 9; /* 4 KB L2 tables */
}
header_size = (header_size + 7) & ~7;
shift = header.cluster_bits + header.l2_bits;
l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift;
header.l1_table_offset = cpu_to_be64(header_size);
if (flags & BLOCK_FLAG_ENCRYPT) {
header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
} else {
header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
}
/* write all the data */
ret = qemu_write_full(fd, &header, sizeof(header));
if (ret != sizeof(header)) {
ret = -errno;
goto exit;
}
if (backing_file) {
ret = qemu_write_full(fd, backing_file, backing_filename_len);
if (ret != backing_filename_len) {
ret = -errno;
goto exit;
}
}
lseek(fd, header_size, SEEK_SET);
tmp = 0;
for(i = 0;i < l1_size; i++) {
ret = qemu_write_full(fd, &tmp, sizeof(tmp));
if (ret != sizeof(tmp)) {
ret = -errno;
goto exit;
}
}
ret = 0;
exit:
close(fd);
return ret;
}
static int qcow_make_empty(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
uint32_t l1_length = s->l1_size * sizeof(uint64_t);
int ret;
memset(s->l1_table, 0, l1_length);
if (bdrv_pwrite(bs->file, s->l1_table_offset, s->l1_table, l1_length) < 0)
return -1;
ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
if (ret < 0)
return ret;
memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
return 0;
}
/* XXX: put compressed sectors first, then all the cluster aligned
tables to avoid losing bytes in alignment */
static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors)
{
BDRVQcowState *s = bs->opaque;
z_stream strm;
int ret, out_len;
uint8_t *out_buf;
uint64_t cluster_offset;
if (nb_sectors != s->cluster_sectors)
return -EINVAL;
out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
if (!out_buf)
return -1;
/* best compression, small window, no zlib header */
memset(&strm, 0, sizeof(strm));
ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
Z_DEFLATED, -12,
9, Z_DEFAULT_STRATEGY);
if (ret != 0) {
qemu_free(out_buf);
return -1;
}
strm.avail_in = s->cluster_size;
strm.next_in = (uint8_t *)buf;
strm.avail_out = s->cluster_size;
strm.next_out = out_buf;
ret = deflate(&strm, Z_FINISH);
if (ret != Z_STREAM_END && ret != Z_OK) {
qemu_free(out_buf);
deflateEnd(&strm);
return -1;
}
out_len = strm.next_out - out_buf;
deflateEnd(&strm);
if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
/* could not compress: write normal cluster */
bdrv_write(bs, sector_num, buf, s->cluster_sectors);
} else {
cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
out_len, 0, 0);
cluster_offset &= s->cluster_offset_mask;
if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
qemu_free(out_buf);
return -1;
}
}
qemu_free(out_buf);
return 0;
}
static void qcow_flush(BlockDriverState *bs)
{
bdrv_flush(bs->file);
}
static BlockDriverAIOCB *qcow_aio_flush(BlockDriverState *bs,
BlockDriverCompletionFunc *cb, void *opaque)
{
return bdrv_aio_flush(bs->file, cb, opaque);
}
static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVQcowState *s = bs->opaque;
bdi->cluster_size = s->cluster_size;
return 0;
}
static QEMUOptionParameter qcow_create_options[] = {
{
.name = BLOCK_OPT_SIZE,
.type = OPT_SIZE,
.help = "Virtual disk size"
},
{
.name = BLOCK_OPT_BACKING_FILE,
.type = OPT_STRING,
.help = "File name of a base image"
},
{
.name = BLOCK_OPT_ENCRYPT,
.type = OPT_FLAG,
.help = "Encrypt the image"
},
{ NULL }
};
static BlockDriver bdrv_qcow = {
.format_name = "qcow",
.instance_size = sizeof(BDRVQcowState),
.bdrv_probe = qcow_probe,
.bdrv_open = qcow_open,
.bdrv_close = qcow_close,
.bdrv_create = qcow_create,
.bdrv_flush = qcow_flush,
.bdrv_is_allocated = qcow_is_allocated,
.bdrv_set_key = qcow_set_key,
.bdrv_make_empty = qcow_make_empty,
.bdrv_aio_readv = qcow_aio_readv,
.bdrv_aio_writev = qcow_aio_writev,
.bdrv_aio_flush = qcow_aio_flush,
.bdrv_write_compressed = qcow_write_compressed,
.bdrv_get_info = qcow_get_info,
.create_options = qcow_create_options,
};
static void bdrv_qcow_init(void)
{
bdrv_register(&bdrv_qcow);
}
block_init(bdrv_qcow_init);
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