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/*
* Compress filter block driver
*
* Copyright (c) 2019 Virtuozzo International GmbH
*
* Author:
* Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
* (based on block/copy-on-read.c by Max Reitz)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 or
* (at your option) any later version of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "block/block_int.h"
#include "qemu/module.h"
#include "qapi/error.h"
static int compress_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
false, errp);
if (!bs->file) {
return -EINVAL;
}
if (!bs->file->bs->drv || !block_driver_can_compress(bs->file->bs->drv)) {
error_setg(errp,
"Compression is not supported for underlying format: %s",
bdrv_get_format_name(bs->file->bs) ?: "(no format)");
return -ENOTSUP;
}
bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
(BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
bs->file->bs->supported_zero_flags);
return 0;
}
static int64_t compress_getlength(BlockDriverState *bs)
{
return bdrv_getlength(bs->file->bs);
}
static int coroutine_fn compress_co_preadv_part(BlockDriverState *bs,
int64_t offset, int64_t bytes,
QEMUIOVector *qiov,
size_t qiov_offset,
BdrvRequestFlags flags)
{
return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset,
flags);
}
static int coroutine_fn compress_co_pwritev_part(BlockDriverState *bs,
int64_t offset,
int64_t bytes,
QEMUIOVector *qiov,
size_t qiov_offset,
BdrvRequestFlags flags)
{
return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset,
flags | BDRV_REQ_WRITE_COMPRESSED);
}
static int coroutine_fn compress_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int64_t bytes,
BdrvRequestFlags flags)
{
return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
}
static int coroutine_fn compress_co_pdiscard(BlockDriverState *bs,
int64_t offset, int64_t bytes)
{
return bdrv_co_pdiscard(bs->file, offset, bytes);
}
static void compress_refresh_limits(BlockDriverState *bs, Error **errp)
{
BlockDriverInfo bdi;
int ret;
if (!bs->file) {
return;
}
ret = bdrv_get_info(bs->file->bs, &bdi);
if (ret < 0 || bdi.cluster_size == 0) {
return;
}
bs->bl.request_alignment = bdi.cluster_size;
}
static void compress_eject(BlockDriverState *bs, bool eject_flag)
{
bdrv_eject(bs->file->bs, eject_flag);
}
static void compress_lock_medium(BlockDriverState *bs, bool locked)
{
bdrv_lock_medium(bs->file->bs, locked);
}
static BlockDriver bdrv_compress = {
.format_name = "compress",
.bdrv_open = compress_open,
.bdrv_child_perm = bdrv_default_perms,
.bdrv_getlength = compress_getlength,
.bdrv_co_preadv_part = compress_co_preadv_part,
.bdrv_co_pwritev_part = compress_co_pwritev_part,
.bdrv_co_pwrite_zeroes = compress_co_pwrite_zeroes,
.bdrv_co_pdiscard = compress_co_pdiscard,
.bdrv_refresh_limits = compress_refresh_limits,
.bdrv_eject = compress_eject,
.bdrv_lock_medium = compress_lock_medium,
.has_variable_length = true,
.is_filter = true,
};
static void bdrv_compress_init(void)
{
bdrv_register(&bdrv_compress);
}
block_init(bdrv_compress_init);
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