Re: [PATCH 01/29] xen/public: add some more 9pfs xenstore paths

[Jason Andryuk <jandryuk@xxxxxxxxx>]

On Wed, Nov 1, 2023 at 7:24 AM Juergen Gross <jgross@xxxxxxxx> wrote:
>
> Add some optional additional backend paths for 9pfs PV devices. Those
> paths will be supported by the new xenlogd 9pfs backend.
>
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> ---
>  xen/include/public/io/9pfs.h | 34 ++++++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
>
> diff --git a/xen/include/public/io/9pfs.h b/xen/include/public/io/9pfs.h
> index 9ad2773082..ac4bf0434b 100644
> --- a/xen/include/public/io/9pfs.h
> +++ b/xen/include/public/io/9pfs.h
> @@ -71,6 +71,40 @@
>   *                 created on the guest (no user ownership squash or remap)
>   *         Only "none" is supported in this version of the protocol.
>   *
> + *    max-files
> + *         Values:        <uint32_t>
> + *
> + *         The maximum number of files (including directories) allowed for
> + *         this device. Backend support of this node is optional. If the node
> + *         is not present or the value is zero the number of files is not
> + *         limited.
> + *
> + *    max-open-files
> + *         Values:        <uint32_t>
> + *
> + *         The maximum number of files the guest is allowed to have opened
> + *         concurrently. Multiple concurrent opens of the same file are 
> counted
> + *         individually. Backend support of this node is optional. If the 
> node
> + *         is not present or the value is zero a backend specific default is
> + *         applied.
> + *
> + *    max-space
> + *         Values:        <uint32_t>
> + *
> + *         The maximum file space in MiBs the guest is allowed to use for 
> this
> + *         device. Backend support of this node is optional. If the node is
> + *         not present or the value is zero the space is not limited.
> + *
> + *    auto-delete
> + *         Values:        <bool>
> + *
> + *         When set to "1" the backend will delete the file with the oldest
> + *         modification date below <path> in case the allowed maximum file
> + *         space (see <max-space>) or file number (see <max-files>) is being
> + *         exceeded due to guest activity (creation or extension of files).
> + *         Files currently opened by the guest won't be deleted. Backend
> + *         support of this node is optional.
> + *

These seem reasonable, but it looks like xenlogd only implements
max-open-files.  They are all marked optional, so I guess it's okay to
include them.  Is there a plan to implement them?  Maybe hold off
until an implementation comes along?

Regards,
Jason