[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v8 1/9] block: add bdrv_measure() API
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH v8 1/9] block: add bdrv_measure() API |
Date: |
Fri, 30 Jun 2017 15:51:09 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 |
On 2017-06-14 17:35, Stefan Hajnoczi wrote:
> bdrv_measure() provides a conservative maximum for the size of a new
> image. This information is handy if storage needs to be allocated (e.g.
> a SAN or an LVM volume) ahead of time.
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> Reviewed-by: Alberto Garcia <address@hidden>
> ---
> v6:
> * Change bdrv_measure() return type to BlockMeasureInfo * [Eric]
> * Clarify that holes in sparse POSIX files are still counted [Eric]
> ---
> qapi/block-core.json | 25 +++++++++++++++++++++++++
> include/block/block.h | 2 ++
> include/block/block_int.h | 2 ++
> block.c | 35 +++++++++++++++++++++++++++++++++++
> 4 files changed, 64 insertions(+)
[...]
> diff --git a/block.c b/block.c
> index fa1d06d..056400a 100644
> --- a/block.c
> +++ b/block.c
> @@ -3446,6 +3446,41 @@ int64_t bdrv_get_allocated_file_size(BlockDriverState
> *bs)
> return -ENOTSUP;
> }
>
> +/*
> + * bdrv_measure:
> + * @drv: Format driver
> + * @opts: Creation options for new image
> + * @in_bs: Existing image containing data for new image (may be NULL)
> + * @errp: Error object
> + * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
> + * or NULL on error
> + *
> + * Calculate file size required to create a new image.
> + *
> + * If @in_bs is given then space for allocated clusters and zero clusters
> + * from that image are included in the calculation. If @opts contains a
> + * backing file that is shared by @in_bs then backing clusters are omitted
> + * from the calculation.
Well, it's a bit weird that qcow2 just doesn't do this, then. :-)
I'm not really complaining (I think it's the best for qcow2 to ignore
this, at least for now), but maybe an s/are/may be/ would be more
appropriate...
(I wouldn't have complained if I hadn't replied to patch 7 anyway.)
Max
> + *
> + * If @in_bs is NULL then the calculation includes no allocated clusters
> + * unless a preallocation option is given in @opts.
> + *
> + * Note that @in_bs may use a different BlockDriver from @drv.
> + *
> + * If an error occurs the @errp pointer is set.
> + */
> +BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
> + BlockDriverState *in_bs, Error **errp)
> +{
> + if (!drv->bdrv_measure) {
> + error_setg(errp, "Block driver '%s' does not support size
> measurement",
> + drv->format_name);
> + return NULL;
> + }
> +
> + return drv->bdrv_measure(opts, in_bs, errp);
> +}
> +
> /**
> * Return number of sectors on success, -errno on error.
> */
>
signature.asc
Description: OpenPGP digital signature
- [Qemu-devel] [PATCH v8 0/9] qemu-img: add measure sub-command, Stefan Hajnoczi, 2017/06/14
- [Qemu-devel] [PATCH v8 1/9] block: add bdrv_measure() API, Stefan Hajnoczi, 2017/06/14
- Re: [Qemu-devel] [PATCH v8 1/9] block: add bdrv_measure() API,
Max Reitz <=
- [Qemu-devel] [PATCH v8 2/9] raw-format: add bdrv_measure() support, Stefan Hajnoczi, 2017/06/14
- [Qemu-devel] [PATCH v8 3/9] qcow2: extract preallocation calculation function, Stefan Hajnoczi, 2017/06/14
- [Qemu-devel] [PATCH v8 4/9] qcow2: make refcount size calculation conservative, Stefan Hajnoczi, 2017/06/14
- [Qemu-devel] [PATCH v8 5/9] qcow2: extract image creation option parsing, Stefan Hajnoczi, 2017/06/14
- [Qemu-devel] [PATCH v8 6/9] qcow2: add bdrv_measure() support, Stefan Hajnoczi, 2017/06/14
- [Qemu-devel] [PATCH v8 7/9] qemu-img: add measure subcommand, Stefan Hajnoczi, 2017/06/14
- [Qemu-devel] [PATCH v8 8/9] qemu-iotests: support per-format golden output files, Stefan Hajnoczi, 2017/06/14