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/*
* Threaded data processing for Qcow2: compression, encryption
*
* Copyright (c) 2004-2006 Fabrice Bellard
* Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved.
*
* 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"
#define ZLIB_CONST
#include <zlib.h>
#include "qcow2.h"
#include "block/thread-pool.h"
#define MAX_COMPRESS_THREADS 4
typedef ssize_t (*Qcow2CompressFunc)(void *dest, size_t dest_size,
const void *src, size_t src_size);
typedef struct Qcow2CompressData {
void *dest;
size_t dest_size;
const void *src;
size_t src_size;
ssize_t ret;
Qcow2CompressFunc func;
} Qcow2CompressData;
/*
* qcow2_compress()
*
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
*
* Returns: compressed size on success
* -ENOMEM destination buffer is not enough to store compressed data
* -EIO on any other error
*/
static ssize_t qcow2_compress(void *dest, size_t dest_size,
const void *src, size_t src_size)
{
ssize_t ret;
z_stream strm;
/* 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 != Z_OK) {
return -EIO;
}
/*
* strm.next_in is not const in old zlib versions, such as those used on
* OpenBSD/NetBSD, so cast the const away
*/
strm.avail_in = src_size;
strm.next_in = (void *) src;
strm.avail_out = dest_size;
strm.next_out = dest;
ret = deflate(&strm, Z_FINISH);
if (ret == Z_STREAM_END) {
ret = dest_size - strm.avail_out;
} else {
ret = (ret == Z_OK ? -ENOMEM : -EIO);
}
deflateEnd(&strm);
return ret;
}
/*
* qcow2_decompress()
*
* Decompress some data (not more than @src_size bytes) to produce exactly
* @dest_size bytes.
*
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
*
* Returns: 0 on success
* -1 on fail
*/
static ssize_t qcow2_decompress(void *dest, size_t dest_size,
const void *src, size_t src_size)
{
int ret = 0;
z_stream strm;
memset(&strm, 0, sizeof(strm));
strm.avail_in = src_size;
strm.next_in = (void *) src;
strm.avail_out = dest_size;
strm.next_out = dest;
ret = inflateInit2(&strm, -12);
if (ret != Z_OK) {
return -1;
}
ret = inflate(&strm, Z_FINISH);
if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || strm.avail_out != 0) {
/*
* We approve Z_BUF_ERROR because we need @dest buffer to be filled, but
* @src buffer may be processed partly (because in qcow2 we know size of
* compressed data with precision of one sector)
*/
ret = -1;
}
inflateEnd(&strm);
return ret;
}
static int qcow2_compress_pool_func(void *opaque)
{
Qcow2CompressData *data = opaque;
data->ret = data->func(data->dest, data->dest_size,
data->src, data->src_size);
return 0;
}
static void qcow2_compress_complete(void *opaque, int ret)
{
qemu_coroutine_enter(opaque);
}
static ssize_t coroutine_fn
qcow2_co_do_compress(BlockDriverState *bs, void *dest, size_t dest_size,
const void *src, size_t src_size, Qcow2CompressFunc func)
{
BDRVQcow2State *s = bs->opaque;
BlockAIOCB *acb;
ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
Qcow2CompressData arg = {
.dest = dest,
.dest_size = dest_size,
.src = src,
.src_size = src_size,
.func = func,
};
while (s->nb_compress_threads >= MAX_COMPRESS_THREADS) {
qemu_co_queue_wait(&s->compress_wait_queue, NULL);
}
s->nb_compress_threads++;
acb = thread_pool_submit_aio(pool, qcow2_compress_pool_func, &arg,
qcow2_compress_complete,
qemu_coroutine_self());
if (!acb) {
s->nb_compress_threads--;
return -EINVAL;
}
qemu_coroutine_yield();
s->nb_compress_threads--;
qemu_co_queue_next(&s->compress_wait_queue);
return arg.ret;
}
ssize_t coroutine_fn
qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
const void *src, size_t src_size)
{
return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
qcow2_compress);
}
ssize_t coroutine_fn
qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
const void *src, size_t src_size)
{
return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
qcow2_decompress);
}
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