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Re: [Qemu-block] [PATCH 2/3] file: Expose some protocol-specific informa
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
Re: [Qemu-block] [PATCH 2/3] file: Expose some protocol-specific information |
Date: |
Fri, 18 Jan 2019 14:08:45 +0000 |
17.01.2019 18:33, Eric Blake wrote:
> When analyzing performance, it might be nice to let 'qemu-img info'
> expose details that it learned from the underlying file or block
> device. Start the process by picking a few useful items determined
> during raw_open_common().
>
> Signed-off-by: Eric Blake <address@hidden>
> ---
> qapi/block-core.json | 24 +++++++++++++++++++++++-
> block/file-posix.c | 21 +++++++++++++++++++++
> 2 files changed, 44 insertions(+), 1 deletion(-)
>
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index f28d5f5fc76..296c22a1003 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -101,6 +101,25 @@
> 'extents': ['ImageInfo']
> } }
>
> +##
> +# @ImageInfoSpecificFile:
> +#
> +# Details about a file protocol BDS.
> +#
> +# @align: Alignment in use
> +#
> +# @discard: True if discard operations can be attempted
> +#
> +# @write-zero: True if efficient write zero operations can be attempted
> +#
> +# @discard-zero: True if discarding is known to read back as zero
> +#
> +# Since: 4.0
> +##
> +{ 'struct': 'ImageInfoSpecificFile',
> + 'data': { 'align': 'int', 'discard': 'bool', 'write-zero': 'bool',
> + '*discard-zero': 'bool' } }
Not sure if this works, as I remember raw-posix will adjust these fields
on first failed write, and without this first write, we will not actually
know are they supported.
> +
> ##
> # @ImageInfoSpecific:
> #
> @@ -110,12 +129,15 @@
> ##
> { 'union': 'ImageInfoSpecific',
> 'data': {
> + # Format drivers:
> 'qcow2': 'ImageInfoSpecificQCow2',
> 'vmdk': 'ImageInfoSpecificVmdk',
> # If we need to add block driver specific parameters for
> # LUKS in future, then we'll subclass QCryptoBlockInfoLUKS
> # to define a ImageInfoSpecificLUKS
> - 'luks': 'QCryptoBlockInfoLUKS'
> + 'luks': 'QCryptoBlockInfoLUKS',
> + # Protocol drivers:
> + 'file': 'ImageInfoSpecificFile'
> } }
>
> ##
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 8aee7a3fb8b..d4ce0e9116c 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -1079,6 +1079,23 @@ static void raw_refresh_limits(BlockDriverState *bs,
> Error **errp)
> bs->bl.opt_mem_alignment = MAX(s->buf_align, getpagesize());
> }
>
> +static ImageInfoSpecific *raw_get_specific_info(BlockDriverState *bs)
> +{
> + BDRVRawState *s = bs->opaque;
> + ImageInfoSpecific *info = g_new0(ImageInfoSpecific, 1);
> + ImageInfoSpecificFile *infofile = g_new0(ImageInfoSpecificFile, 1);
> +
> + info->type = IMAGE_INFO_SPECIFIC_KIND_FILE;
> + info->u.file.data = infofile;
> + infofile->align = s->buf_align;
> + infofile->discard = s->has_discard;
> + infofile->write_zero = s->has_write_zeroes;
> + infofile->has_discard_zero = s->has_discard;
> + infofile->discard_zero = s->discard_zeroes;
> +
> + return info;
> +}
> +
> static int check_for_dasd(int fd)
> {
> #ifdef BIODASDINFO2
> @@ -2765,6 +2782,7 @@ BlockDriver bdrv_file = {
> .bdrv_co_copy_range_from = raw_co_copy_range_from,
> .bdrv_co_copy_range_to = raw_co_copy_range_to,
> .bdrv_refresh_limits = raw_refresh_limits,
> + .bdrv_get_specific_info = raw_get_specific_info,
> .bdrv_io_plug = raw_aio_plug,
> .bdrv_io_unplug = raw_aio_unplug,
> .bdrv_attach_aio_context = raw_aio_attach_aio_context,
> @@ -3240,6 +3258,7 @@ static BlockDriver bdrv_host_device = {
> .bdrv_co_copy_range_from = raw_co_copy_range_from,
> .bdrv_co_copy_range_to = raw_co_copy_range_to,
> .bdrv_refresh_limits = raw_refresh_limits,
> + .bdrv_get_specific_info = raw_get_specific_info,
> .bdrv_io_plug = raw_aio_plug,
> .bdrv_io_unplug = raw_aio_unplug,
> .bdrv_attach_aio_context = raw_aio_attach_aio_context,
> @@ -3363,6 +3382,7 @@ static BlockDriver bdrv_host_cdrom = {
> .bdrv_co_pwritev = raw_co_pwritev,
> .bdrv_co_flush_to_disk = raw_co_flush_to_disk,
> .bdrv_refresh_limits = raw_refresh_limits,
> + .bdrv_get_specific_info = raw_get_specific_info,
> .bdrv_io_plug = raw_aio_plug,
> .bdrv_io_unplug = raw_aio_unplug,
> .bdrv_attach_aio_context = raw_aio_attach_aio_context,
> @@ -3494,6 +3514,7 @@ static BlockDriver bdrv_host_cdrom = {
> .bdrv_co_pwritev = raw_co_pwritev,
> .bdrv_co_flush_to_disk = raw_co_flush_to_disk,
> .bdrv_refresh_limits = raw_refresh_limits,
> + .bdrv_get_specific_info = raw_get_specific_info,
> .bdrv_io_plug = raw_aio_plug,
> .bdrv_io_unplug = raw_aio_unplug,
> .bdrv_attach_aio_context = raw_aio_attach_aio_context,
>
--
Best regards,
Vladimir