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qemu/block/qcow.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/osdep.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "block/block_int.h"
#include "block/qdict.h"
#include "sysemu/block-backend.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qemu/bswap.h"
#include <zlib.h>
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/qapi-visit-block-core.h"
#include "crypto/block.h"
#include "migration/blocker.h"
#include "crypto.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;
uint16_t padding;
uint32_t crypt_method;
uint64_t l1_table_offset;
} QEMU_PACKED QCowHeader;
#define L2_CACHE_SIZE 16
typedef struct BDRVQcowState {
int cluster_bits;
int cluster_size;
int l2_bits;
int l2_size;
unsigned 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;
QCryptoBlock *crypto; /* Disk encryption format driver */
uint32_t crypt_method_header;
CoMutex lock;
Error *migration_blocker;
} BDRVQcowState;
static QemuOptsList qcow_create_opts;
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 QemuOptsList qcow_runtime_opts = {
.name = "qcow",
.head = QTAILQ_HEAD_INITIALIZER(qcow_runtime_opts.head),
.desc = {
BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
{ /* end of list */ }
},
};
static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVQcowState *s = bs->opaque;
unsigned int len, i, shift;
int ret;
QCowHeader header;
Error *local_err = NULL;
QCryptoBlockOpenOptions *crypto_opts = NULL;
unsigned int cflags = 0;
QDict *encryptopts = NULL;
const char *encryptfmt;
qdict_extract_subqdict(options, &encryptopts, "encrypt.");
encryptfmt = qdict_get_try_str(encryptopts, "format");
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
false, errp);
if (!bs->file) {
ret = -EINVAL;
goto fail;
}
ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
if (ret < 0) {
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) {
error_setg(errp, "Image not in qcow format");
ret = -EINVAL;
goto fail;
}
if (header.version != QCOW_VERSION) {
error_setg(errp, "Unsupported qcow version %" PRIu32, header.version);
ret = -ENOTSUP;
goto fail;
}
if (header.size <= 1) {
error_setg(errp, "Image size is too small (must be at least 2 bytes)");
ret = -EINVAL;
goto fail;
}
if (header.cluster_bits < 9 || header.cluster_bits > 16) {
error_setg(errp, "Cluster size must be between 512 and 64k");
ret = -EINVAL;
goto fail;
}
/* l2_bits specifies number of entries; storing a uint64_t in each entry,
* so bytes = num_entries << 3. */
if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
error_setg(errp, "L2 table size must be between 512 and 64k");
ret = -EINVAL;
goto fail;
}
s->crypt_method_header = header.crypt_method;
if (s->crypt_method_header) {
if (bdrv_uses_whitelist() &&
s->crypt_method_header == QCOW_CRYPT_AES) {
error_setg(errp,
"Use of AES-CBC encrypted qcow images is no longer "
"supported in system emulators");
error_append_hint(errp,
"You can use 'qemu-img convert' to convert your "
"image to an alternative supported format, such "
"as unencrypted qcow, or raw with the LUKS "
"format instead.\n");
ret = -ENOSYS;
goto fail;
}
if (s->crypt_method_header == QCOW_CRYPT_AES) {
if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
error_setg(errp,
"Header reported 'aes' encryption format but "
"options specify '%s'", encryptfmt);
ret = -EINVAL;
goto fail;
}
qdict_put_str(encryptopts, "format", "qcow");
crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
if (!crypto_opts) {
ret = -EINVAL;
goto fail;
}
if (flags & BDRV_O_NO_IO) {
cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
}
s->crypto = qcrypto_block_open(crypto_opts, "encrypt.",
NULL, NULL, cflags, errp);
if (!s->crypto) {
ret = -EINVAL;
goto fail;
}
} else {
error_setg(errp, "invalid encryption method in qcow header");
ret = -EINVAL;
goto fail;
}
bs->encrypted = true;
} else {
if (encryptfmt) {
error_setg(errp, "No encryption in image header, but options "
"specified format '%s'", encryptfmt);
ret = -EINVAL;
goto fail;
}
}
s->cluster_bits = header.cluster_bits;
s->cluster_size = 1 << s->cluster_bits;
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;
if (header.size > UINT64_MAX - (1LL << shift)) {
error_setg(errp, "Image too large");
ret = -EINVAL;
goto fail;
} else {
uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
if (l1_size > INT_MAX / sizeof(uint64_t)) {
error_setg(errp, "Image too large");
ret = -EINVAL;
goto fail;
}
s->l1_size = l1_size;
}
s->l1_table_offset = header.l1_table_offset;
s->l1_table = g_try_new(uint64_t, s->l1_size);
if (s->l1_table == NULL) {
error_setg(errp, "Could not allocate memory for L1 table");
ret = -ENOMEM;
goto fail;
}
ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
s->l1_size * sizeof(uint64_t));
if (ret < 0) {
goto fail;
}
for(i = 0;i < s->l1_size; i++) {
be64_to_cpus(&s->l1_table[i]);
}
/* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
s->l2_cache =
qemu_try_blockalign(bs->file->bs,
s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
if (s->l2_cache == NULL) {
error_setg(errp, "Could not allocate L2 table cache");
ret = -ENOMEM;
goto fail;
}
s->cluster_cache = g_malloc(s->cluster_size);
s->cluster_data = g_malloc(s->cluster_size);
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 >= sizeof(bs->backing_file)) {
error_setg(errp, "Backing file name too long");
ret = -EINVAL;
goto fail;
}
ret = bdrv_pread(bs->file, header.backing_file_offset,
bs->backing_file, len);
if (ret < 0) {
goto fail;
}
bs->backing_file[len] = '\0';
}
/* Disable migration when qcow images are used */
error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
ret = migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
error_free(s->migration_blocker);
goto fail;
}
qobject_unref(encryptopts);
qapi_free_QCryptoBlockOpenOptions(crypto_opts);
qemu_co_mutex_init(&s->lock);
return 0;
fail:
g_free(s->l1_table);
qemu_vfree(s->l2_cache);
g_free(s->cluster_cache);
g_free(s->cluster_data);
qcrypto_block_free(s->crypto);
qobject_unref(encryptopts);
qapi_free_QCryptoBlockOpenOptions(crypto_opts);
return ret;
}
/* We have nothing to do for QCOW reopen, stubs just return
* success */
static int qcow_reopen_prepare(BDRVReopenState *state,
BlockReopenQueue *queue, Error **errp)
{
return 0;
}
/* 'allocate' is:
*
* 0 to not allocate.
*
* 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start'
* to 'n_end' within the cluster)
*
* 2 to allocate a compressed cluster of size
* 'compressed_size'. 'compressed_size' must be > 0 and <
* cluster_size
*
* return 0 if not allocated, 1 if *result is assigned, and negative
* errno on failure.
*/
static int get_cluster_offset(BlockDriverState *bs,
uint64_t offset, int allocate,
int compressed_size,
int n_start, int n_end, uint64_t *result)
{
BDRVQcowState *s = bs->opaque;
int min_index, i, j, l1_index, l2_index, ret;
int64_t l2_offset;
uint64_t *l2_table, cluster_offset, tmp;
uint32_t min_count;
int new_l2_table;
*result = 0;
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->bs);
if (l2_offset < 0) {
return l2_offset;
}
/* round to cluster size */
l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size);
/* update the L1 entry */
s->l1_table[l1_index] = l2_offset;
tmp = cpu_to_be64(l2_offset);
BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
ret = bdrv_pwrite_sync(bs->file,
s->l1_table_offset + l1_index * sizeof(tmp),
&tmp, sizeof(tmp));
if (ret < 0) {
return ret;
}
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);
BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
if (new_l2_table) {
memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
s->l2_size * sizeof(uint64_t));
if (ret < 0) {
return ret;
}
} else {
ret = bdrv_pread(bs->file, l2_offset, l2_table,
s->l2_size * sizeof(uint64_t));
if (ret < 0) {
return ret;
}
}
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;
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE));
/* allocate a new cluster */
if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
(n_end - n_start) < s->cluster_size) {
/* 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 -EIO;
}
cluster_offset = bdrv_getlength(bs->file->bs);
if ((int64_t) cluster_offset < 0) {
return cluster_offset;
}
cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
/* write the cluster content */
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache,
s->cluster_size);
if (ret < 0) {
return ret;
}
} else {
cluster_offset = bdrv_getlength(bs->file->bs);
if ((int64_t) cluster_offset < 0) {
return cluster_offset;
}
if (allocate == 1) {
/* round to cluster size */
cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
if (cluster_offset + s->cluster_size > INT64_MAX) {
return -E2BIG;
}
ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size,
PREALLOC_MODE_OFF, NULL);
if (ret < 0) {
return ret;
}
/* if encrypted, we must initialize the cluster
content which won't be written */
if (bs->encrypted &&
(n_end - n_start) < s->cluster_size) {
uint64_t start_offset;
assert(s->crypto);
start_offset = offset & ~(s->cluster_size - 1);
for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) {
if (i < n_start || i >= n_end) {
memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE);
if (qcrypto_block_encrypt(s->crypto,
start_offset + i,
s->cluster_data,
BDRV_SECTOR_SIZE,
NULL) < 0) {
return -EIO;
}
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
ret = bdrv_pwrite(bs->file,
cluster_offset + i,
s->cluster_data,
BDRV_SECTOR_SIZE);
if (ret < 0) {
return ret;
}
}
}
}
} 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 (allocate == 2) {
BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
} else {
BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
}
ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
&tmp, sizeof(tmp));
if (ret < 0) {
return ret;
}
}
*result = cluster_offset;
return 1;
}
static int coroutine_fn qcow_co_block_status(BlockDriverState *bs,
bool want_zero,
int64_t offset, int64_t bytes,
int64_t *pnum, int64_t *map,
BlockDriverState **file)
{
BDRVQcowState *s = bs->opaque;
int index_in_cluster, ret;
int64_t n;
uint64_t cluster_offset;
qemu_co_mutex_lock(&s->lock);
ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
qemu_co_mutex_unlock(&s->lock);
if (ret < 0) {
return ret;
}
index_in_cluster = offset & (s->cluster_size - 1);
n = s->cluster_size - index_in_cluster;
if (n > bytes) {
n = bytes;
}
*pnum = n;
if (!cluster_offset) {
return 0;
}
if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) {
return BDRV_BLOCK_DATA;
}
*map = cluster_offset | index_in_cluster;
*file = bs->file->bs;
return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
}
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);
BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
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;
}
static void qcow_refresh_limits(BlockDriverState *bs, Error **errp)
{
/* At least encrypted images require 512-byte alignment. Apply the
* limit universally, rather than just on encrypted images, as
* it's easier to let the block layer handle rounding than to
* audit this code further. */
bs->bl.request_alignment = BDRV_SECTOR_SIZE;
}
static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
BDRVQcowState *s = bs->opaque;
int offset_in_cluster;
int ret = 0, n;
uint64_t cluster_offset;
struct iovec hd_iov;
QEMUIOVector hd_qiov;
uint8_t *buf;
void *orig_buf;
assert(!flags);
if (qiov->niov > 1) {
buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
if (buf == NULL) {
return -ENOMEM;
}
} else {
orig_buf = NULL;
buf = (uint8_t *)qiov->iov->iov_base;
}
qemu_co_mutex_lock(&s->lock);
while (bytes != 0) {
/* prepare next request */
ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
if (ret < 0) {
break;
}
offset_in_cluster = offset & (s->cluster_size - 1);
n = s->cluster_size - offset_in_cluster;
if (n > bytes) {
n = bytes;
}
if (!cluster_offset) {
if (bs->backing) {
/* read from the base image */
hd_iov.iov_base = (void *)buf;
hd_iov.iov_len = n;
qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
qemu_co_mutex_unlock(&s->lock);
/* qcow2 emits this on bs->file instead of bs->backing */
BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
ret = bdrv_co_preadv(bs->backing, offset, n, &hd_qiov, 0);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
break;
}
} else {
/* Note: in this case, no need to wait */
memset(buf, 0, n);
}
} else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
/* add AIO support for compressed blocks ? */
if (decompress_cluster(bs, cluster_offset) < 0) {
ret = -EIO;
break;
}
memcpy(buf, s->cluster_cache + offset_in_cluster, n);
} else {
if ((cluster_offset & 511) != 0) {
ret = -EIO;
break;
}
hd_iov.iov_base = (void *)buf;
hd_iov.iov_len = n;
qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
qemu_co_mutex_unlock(&s->lock);
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
ret = bdrv_co_preadv(bs->file, cluster_offset + offset_in_cluster,
n, &hd_qiov, 0);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
break;
}
if (bs->encrypted) {
assert(s->crypto);
if (qcrypto_block_decrypt(s->crypto,
offset, buf, n, NULL) < 0) {
ret = -EIO;
break;
}
}
}
ret = 0;
bytes -= n;
offset += n;
buf += n;
}
qemu_co_mutex_unlock(&s->lock);
if (qiov->niov > 1) {
qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
qemu_vfree(orig_buf);
}
return ret;
}
static coroutine_fn int qcow_co_pwritev(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
BDRVQcowState *s = bs->opaque;
int offset_in_cluster;
uint64_t cluster_offset;
int ret = 0, n;
struct iovec hd_iov;
QEMUIOVector hd_qiov;
uint8_t *buf;
void *orig_buf;
assert(!flags);
s->cluster_cache_offset = -1; /* disable compressed cache */
/* We must always copy the iov when encrypting, so we
* don't modify the original data buffer during encryption */
if (bs->encrypted || qiov->niov > 1) {
buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
if (buf == NULL) {
return -ENOMEM;
}
qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
} else {
orig_buf = NULL;
buf = (uint8_t *)qiov->iov->iov_base;
}
qemu_co_mutex_lock(&s->lock);
while (bytes != 0) {
offset_in_cluster = offset & (s->cluster_size - 1);
n = s->cluster_size - offset_in_cluster;
if (n > bytes) {
n = bytes;
}
ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster,
offset_in_cluster + n, &cluster_offset);
if (ret < 0) {
break;
}
if (!cluster_offset || (cluster_offset & 511) != 0) {
ret = -EIO;
break;
}
if (bs->encrypted) {
assert(s->crypto);
if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) {
ret = -EIO;
break;
}
}
hd_iov.iov_base = (void *)buf;
hd_iov.iov_len = n;
qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
qemu_co_mutex_unlock(&s->lock);
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
ret = bdrv_co_pwritev(bs->file, cluster_offset + offset_in_cluster,
n, &hd_qiov, 0);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
break;
}
ret = 0;
bytes -= n;
offset += n;
buf += n;
}
qemu_co_mutex_unlock(&s->lock);
qemu_vfree(orig_buf);
return ret;
}
static void qcow_close(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
qcrypto_block_free(s->crypto);
s->crypto = NULL;
g_free(s->l1_table);
qemu_vfree(s->l2_cache);
g_free(s->cluster_cache);
g_free(s->cluster_data);
migrate_del_blocker(s->migration_blocker);
error_free(s->migration_blocker);
}
static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts,
Error **errp)
{
BlockdevCreateOptionsQcow *qcow_opts;
int header_size, backing_filename_len, l1_size, shift, i;
QCowHeader header;
uint8_t *tmp;
int64_t total_size = 0;
int ret;
BlockDriverState *bs;
BlockBackend *qcow_blk;
QCryptoBlock *crypto = NULL;
assert(opts->driver == BLOCKDEV_DRIVER_QCOW);
qcow_opts = &opts->u.qcow;
/* Sanity checks */
total_size = qcow_opts->size;
if (total_size == 0) {
error_setg(errp, "Image size is too small, cannot be zero length");
return -EINVAL;
}
if (qcow_opts->has_encrypt &&
qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW)
{
error_setg(errp, "Unsupported encryption format");
return -EINVAL;
}
/* Create BlockBackend to write to the image */
bs = bdrv_open_blockdev_ref(qcow_opts->file, errp);
if (bs == NULL) {
return -EIO;
}
qcow_blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
ret = blk_insert_bs(qcow_blk, bs, errp);
if (ret < 0) {
goto exit;
}
blk_set_allow_write_beyond_eof(qcow_blk, true);
/* Create image format */
ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp);
if (ret < 0) {
goto exit;
}
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);
header_size = sizeof(header);
backing_filename_len = 0;
if (qcow_opts->has_backing_file) {
if (strcmp(qcow_opts->backing_file, "fat:")) {
header.backing_file_offset = cpu_to_be64(header_size);
backing_filename_len = strlen(qcow_opts->backing_file);
header.backing_file_size = cpu_to_be32(backing_filename_len);
header_size += backing_filename_len;
} else {
/* special backing file for vvfat */
qcow_opts->has_backing_file = false;
}
header.cluster_bits = 9; /* 512 byte cluster to avoid copying
unmodified 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 + (1LL << shift) - 1) >> shift;
header.l1_table_offset = cpu_to_be64(header_size);
if (qcow_opts->has_encrypt) {
header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.",
NULL, NULL, NULL, errp);
if (!crypto) {
ret = -EINVAL;
goto exit;
}
} else {
header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
}
/* write all the data */
ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0);
if (ret != sizeof(header)) {
goto exit;
}
if (qcow_opts->has_backing_file) {
ret = blk_pwrite(qcow_blk, sizeof(header),
qcow_opts->backing_file, backing_filename_len, 0);
if (ret != backing_filename_len) {
goto exit;
}
}
tmp = g_malloc0(BDRV_SECTOR_SIZE);
for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
i++) {
ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
tmp, BDRV_SECTOR_SIZE, 0);
if (ret != BDRV_SECTOR_SIZE) {
g_free(tmp);
goto exit;
}
}
g_free(tmp);
ret = 0;
exit:
blk_unref(qcow_blk);
qcrypto_block_free(crypto);
return ret;
}
static int coroutine_fn qcow_co_create_opts(const char *filename,
QemuOpts *opts, Error **errp)
{
BlockdevCreateOptions *create_options = NULL;
BlockDriverState *bs = NULL;
QDict *qdict;
Visitor *v;
const char *val;
Error *local_err = NULL;
int ret;
static const QDictRenames opt_renames[] = {
{ BLOCK_OPT_BACKING_FILE, "backing-file" },
{ BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
{ NULL, NULL },
};
/* Parse options and convert legacy syntax */
qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);
val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
if (val && !strcmp(val, "on")) {
qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
} else if (val && !strcmp(val, "off")) {
qdict_del(qdict, BLOCK_OPT_ENCRYPT);
}
val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
if (val && !strcmp(val, "aes")) {
qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
}
if (!qdict_rename_keys(qdict, opt_renames, errp)) {
ret = -EINVAL;
goto fail;
}
/* Create and open the file (protocol layer) */
ret = bdrv_create_file(filename, opts, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
goto fail;
}
bs = bdrv_open(filename, NULL, NULL,
BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
if (bs == NULL) {
ret = -EIO;
goto fail;
}
/* Now get the QAPI type BlockdevCreateOptions */
qdict_put_str(qdict, "driver", "qcow");
qdict_put_str(qdict, "file", bs->node_name);
v = qobject_input_visitor_new_flat_confused(qdict, errp);
if (!v) {
ret = -EINVAL;
goto fail;
}
visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err);
visit_free(v);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
/* Silently round up size */
assert(create_options->driver == BLOCKDEV_DRIVER_QCOW);
create_options->u.qcow.size =
ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE);
/* Create the qcow image (format layer) */
ret = qcow_co_create(create_options, errp);
if (ret < 0) {
goto fail;
}
ret = 0;
fail:
qobject_unref(qdict);
bdrv_unref(bs);
qapi_free_BlockdevCreateOptions(create_options);
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_sync(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,
PREALLOC_MODE_OFF, NULL);
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 coroutine_fn int
qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov)
{
BDRVQcowState *s = bs->opaque;
QEMUIOVector hd_qiov;
struct iovec iov;
z_stream strm;
int ret, out_len;
uint8_t *buf, *out_buf;
uint64_t cluster_offset;
buf = qemu_blockalign(bs, s->cluster_size);
if (bytes != s->cluster_size) {
if (bytes > s->cluster_size ||
offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
{
qemu_vfree(buf);
return -EINVAL;
}
/* Zero-pad last write if image size is not cluster aligned */
memset(buf + bytes, 0, s->cluster_size - bytes);
}
qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
out_buf = g_malloc(s->cluster_size);
/* 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) {
ret = -EINVAL;
goto fail;
}
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) {
deflateEnd(&strm);
ret = -EINVAL;
goto fail;
}
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 */
ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0);
if (ret < 0) {
goto fail;
}
goto success;
}
qemu_co_mutex_lock(&s->lock);
ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
qemu_co_mutex_unlock(&s->lock);
if (ret < 0) {
goto fail;
}
if (cluster_offset == 0) {
ret = -EIO;
goto fail;
}
cluster_offset &= s->cluster_offset_mask;
iov = (struct iovec) {
.iov_base = out_buf,
.iov_len = out_len,
};
qemu_iovec_init_external(&hd_qiov, &iov, 1);
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0);
if (ret < 0) {
goto fail;
}
success:
ret = 0;
fail:
qemu_vfree(buf);
g_free(out_buf);
return ret;
}
static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVQcowState *s = bs->opaque;
bdi->cluster_size = s->cluster_size;
return 0;
}
static QemuOptsList qcow_create_opts = {
.name = "qcow-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{
.name = BLOCK_OPT_BACKING_FILE,
.type = QEMU_OPT_STRING,
.help = "File name of a base image"
},
{
.name = BLOCK_OPT_ENCRYPT,
.type = QEMU_OPT_BOOL,
.help = "Encrypt the image with format 'aes'. (Deprecated "
"in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
},
{
.name = BLOCK_OPT_ENCRYPT_FORMAT,
.type = QEMU_OPT_STRING,
.help = "Encrypt the image, format choices: 'aes'",
},
BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
{ /* end of list */ }
}
};
static BlockDriver bdrv_qcow = {
.format_name = "qcow",
.instance_size = sizeof(BDRVQcowState),
.bdrv_probe = qcow_probe,
.bdrv_open = qcow_open,
.bdrv_close = qcow_close,
.bdrv_child_perm = bdrv_format_default_perms,
.bdrv_reopen_prepare = qcow_reopen_prepare,
.bdrv_co_create = qcow_co_create,
.bdrv_co_create_opts = qcow_co_create_opts,
.bdrv_has_zero_init = bdrv_has_zero_init_1,
.supports_backing = true,
.bdrv_refresh_limits = qcow_refresh_limits,
.bdrv_co_preadv = qcow_co_preadv,
.bdrv_co_pwritev = qcow_co_pwritev,
.bdrv_co_block_status = qcow_co_block_status,
.bdrv_make_empty = qcow_make_empty,
.bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
.bdrv_get_info = qcow_get_info,
.create_opts = &qcow_create_opts,
};
static void bdrv_qcow_init(void)
{
bdrv_register(&bdrv_qcow);
}
block_init(bdrv_qcow_init);
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