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Diffstat (limited to 'block/qcow2-threads.c')
| -rw-r--r-- | block/qcow2-threads.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c new file mode 100644 index 0000000000..85b8034fd2 --- /dev/null +++ b/block/qcow2-threads.c @@ -0,0 +1,201 @@ +/* + * 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); +} |