159 lines
4.9 KiB
C
159 lines
4.9 KiB
C
/*
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* Compress filter block driver
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*
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* Copyright (c) 2019 Virtuozzo International GmbH
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*
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* Author:
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* Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
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* (based on block/copy-on-read.c by Max Reitz)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 or
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* (at your option) any later version of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "block/block_int.h"
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#include "qemu/module.h"
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#include "qapi/error.h"
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static int compress_open(BlockDriverState *bs, QDict *options, int flags,
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Error **errp)
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{
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bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
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BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
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false, errp);
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if (!bs->file) {
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return -EINVAL;
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}
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if (!bs->file->bs->drv || !block_driver_can_compress(bs->file->bs->drv)) {
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error_setg(errp,
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"Compression is not supported for underlying format: %s",
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bdrv_get_format_name(bs->file->bs) ?: "(no format)");
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return -ENOTSUP;
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}
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bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
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(BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
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bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
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((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
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bs->file->bs->supported_zero_flags);
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return 0;
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}
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static int64_t compress_getlength(BlockDriverState *bs)
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{
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return bdrv_getlength(bs->file->bs);
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}
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static int coroutine_fn compress_co_preadv_part(BlockDriverState *bs,
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uint64_t offset, uint64_t bytes,
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QEMUIOVector *qiov,
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size_t qiov_offset,
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int flags)
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{
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return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset,
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flags);
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}
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static int coroutine_fn compress_co_pwritev_part(BlockDriverState *bs,
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uint64_t offset,
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uint64_t bytes,
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QEMUIOVector *qiov,
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size_t qiov_offset, int flags)
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{
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return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset,
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flags | BDRV_REQ_WRITE_COMPRESSED);
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}
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static int coroutine_fn compress_co_pwrite_zeroes(BlockDriverState *bs,
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int64_t offset, int bytes,
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BdrvRequestFlags flags)
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{
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return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
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}
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static int coroutine_fn compress_co_pdiscard(BlockDriverState *bs,
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int64_t offset, int bytes)
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{
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return bdrv_co_pdiscard(bs->file, offset, bytes);
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}
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static void compress_refresh_limits(BlockDriverState *bs, Error **errp)
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{
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BlockDriverInfo bdi;
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int ret;
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if (!bs->file) {
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return;
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}
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ret = bdrv_get_info(bs->file->bs, &bdi);
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if (ret < 0 || bdi.cluster_size == 0) {
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return;
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}
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bs->bl.request_alignment = bdi.cluster_size;
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}
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static void compress_eject(BlockDriverState *bs, bool eject_flag)
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{
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bdrv_eject(bs->file->bs, eject_flag);
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}
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static void compress_lock_medium(BlockDriverState *bs, bool locked)
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{
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bdrv_lock_medium(bs->file->bs, locked);
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}
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static BlockDriver bdrv_compress = {
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.format_name = "compress",
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.bdrv_open = compress_open,
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.bdrv_child_perm = bdrv_default_perms,
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.bdrv_getlength = compress_getlength,
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.bdrv_co_preadv_part = compress_co_preadv_part,
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.bdrv_co_pwritev_part = compress_co_pwritev_part,
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.bdrv_co_pwrite_zeroes = compress_co_pwrite_zeroes,
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.bdrv_co_pdiscard = compress_co_pdiscard,
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.bdrv_refresh_limits = compress_refresh_limits,
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.bdrv_eject = compress_eject,
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.bdrv_lock_medium = compress_lock_medium,
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.has_variable_length = true,
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.is_filter = true,
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};
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static void bdrv_compress_init(void)
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{
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bdrv_register(&bdrv_compress);
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}
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block_init(bdrv_compress_init);
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