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Re: [PATCH v10 1/3] block: introduce compress filter driver
From: |
Andrey Shinkevich |
Subject: |
Re: [PATCH v10 1/3] block: introduce compress filter driver |
Date: |
Mon, 2 Dec 2019 09:53:52 +0000 |
On 28/11/2019 17:37, Vladimir Sementsov-Ogievskiy wrote:
> 28.11.2019 12:36, Andrey Shinkevich wrote:
>> Allow writing all the data compressed through the filter driver.
>> The written data will be aligned by the cluster size.
>> Based on the QEMU current implementation, that data can be written to
>> unallocated clusters only. May be used for a backup job.
>>
>> Suggested-by: Max Reitz <address@hidden>
>> Signed-off-by: Andrey Shinkevich <address@hidden>
>> ---
>> block/Makefile.objs | 1 +
>> block/filter-compress.c | 166
>> ++++++++++++++++++++++++++++++++++++++++++++++++
>> qapi/block-core.json | 10 +--
>> 3 files changed, 173 insertions(+), 4 deletions(-)
>> create mode 100644 block/filter-compress.c
>>
>> diff --git a/block/Makefile.objs b/block/Makefile.objs
>> index e394fe0..330529b 100644
>> --- a/block/Makefile.objs
>> +++ b/block/Makefile.objs
>> @@ -43,6 +43,7 @@ block-obj-y += crypto.o
>>
>> block-obj-y += aio_task.o
>> block-obj-y += backup-top.o
>> +block-obj-y += filter-compress.o
>>
>> common-obj-y += stream.o
>>
>> diff --git a/block/filter-compress.c b/block/filter-compress.c
>> new file mode 100644
>> index 0000000..4aa189b
>> --- /dev/null
>> +++ b/block/filter-compress.c
>> @@ -0,0 +1,166 @@
>> +/*
>> + * Compress filter block driver
>> + *
>> + * Copyright (c) 2019 Virtuozzo International GmbH
>> + *
>> + * Author:
>> + * Andrey Shinkevich <address@hidden>
>> + * (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_file,
>> 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 with this drive %s",
>> + bdrv_get_device_name(bs->file->bs));
>
> I think we should rollback bdrv_open_child in this case.
>
It is processed in the 'open_failed' section of the bdrv_open_driver()
Andrey
> Also I doubt that bdrv_get_device_name will work properly here. I think better
> something like
> "Compression is not supported for underlying format: %s",
> bdrv_get_format_name(bs)
>
>> + 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,
>> + uint64_t offset, uint64_t
>> bytes,
>> + QEMUIOVector *qiov,
>> + size_t qiov_offset,
>> + int flags)
>> +{
>> + return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset,
>> + flags);
>> +}
>> +
>> +
>> +static int coroutine_fn compress_co_pwritev_part(BlockDriverState *bs,
>> + uint64_t offset,
>> + uint64_t bytes,
>> + QEMUIOVector *qiov,
>> + size_t qiov_offset, int
>> 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, int 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, int 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 bool compress_recurse_is_first_non_filter(BlockDriverState *bs,
>> + BlockDriverState
>> *candidate)
>> +{
>> + return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate);
>> +}
>> +
>> +
>> +static BlockDriver bdrv_compress = {
>> + .format_name = "compress",
>> +
>> + .bdrv_open = compress_open,
>> + .bdrv_child_perm = bdrv_filter_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,
>> +
>> + .bdrv_co_block_status = bdrv_co_block_status_from_backing,
>> +
>> + .bdrv_recurse_is_first_non_filter =
>> compress_recurse_is_first_non_filter,
>> +
>> + .has_variable_length = true,
>> + .is_filter = true,
>> +};
>> +
>> +static void bdrv_compress_init(void)
>> +{
>> + bdrv_register(&bdrv_compress);
>> +}
>> +
>> +block_init(bdrv_compress_init);
>> diff --git a/qapi/block-core.json b/qapi/block-core.json
>> index 0cf68fe..93ee04e 100644
>> --- a/qapi/block-core.json
>> +++ b/qapi/block-core.json
>> @@ -2884,15 +2884,16 @@
>> # @copy-on-read: Since 3.0
>> # @blklogwrites: Since 3.0
>> # @blkreplay: Since 4.2
>> +# @compress: Since 5.0
>> #
>> # Since: 2.9
>> ##
>> { 'enum': 'BlockdevDriver',
>> 'data': [ 'blkdebug', 'blklogwrites', 'blkreplay', 'blkverify', 'bochs',
>> - 'cloop', 'copy-on-read', 'dmg', 'file', 'ftp', 'ftps',
>> 'gluster',
>> - 'host_cdrom', 'host_device', 'http', 'https', 'iscsi', 'luks',
>> - 'nbd', 'nfs', 'null-aio', 'null-co', 'nvme', 'parallels',
>> 'qcow',
>> - 'qcow2', 'qed', 'quorum', 'raw', 'rbd',
>> + 'cloop', 'compress', 'copy-on-read', 'dmg', 'file', 'ftp',
>> 'ftps',
>> + 'gluster', 'host_cdrom', 'host_device', 'http', 'https',
>> 'iscsi',
>> + 'luks', 'nbd', 'nfs', 'null-aio', 'null-co', 'nvme',
>> 'parallels',
>> + 'qcow', 'qcow2', 'qed', 'quorum', 'raw', 'rbd',
>> { 'name': 'replication', 'if': 'defined(CONFIG_REPLICATION)'
>> },
>> 'sheepdog',
>> 'ssh', 'throttle', 'vdi', 'vhdx', 'vmdk', 'vpc', 'vvfat',
>> 'vxhs' ] }
>> @@ -4044,6 +4045,7 @@
>> 'blkreplay': 'BlockdevOptionsBlkreplay',
>> 'bochs': 'BlockdevOptionsGenericFormat',
>> 'cloop': 'BlockdevOptionsGenericFormat',
>> + 'compress': 'BlockdevOptionsGenericFormat',
>> 'copy-on-read':'BlockdevOptionsGenericFormat',
>> 'dmg': 'BlockdevOptionsGenericFormat',
>> 'file': 'BlockdevOptionsFile',
>>
>
>
--
With the best regards,
Andrey Shinkevich
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