Re: [PATCH] Interpret "removable" and "info" flags correctly

["Durrant, Paul" <xadimgnik@xxxxxxxxx>]

On 30/11/2021 08:06, Owen Smith wrote:
> "removable" relates to the ability to remove the device (not media)
>
>    "removable" = "1" is used to indicate the device can be hot unplugged, as
>    PV devices should support hot plug/unplug in the majority of cases.
>    "removable" = "0" is used to indicate that the device is being prevented
>    from hot unplug by the tool stack. This will allow XenVbd to report the
>    correct device capabilities to the OS to indicate that this disk is not
>    capable of being removed. This will allow certain policies to be applied
>    which restrict access to removable disks (for security and to prevent data
>    exfiltration)
>
> "info" contains various flags for the media (not device)
>
>    VDISK_CDROM implies RemovableMedia (a specific case of VDISK_REMOVABLE)
>    VDISK_REMOVABLE imples RemovableMedia (underlying disk has 
> GENHD_FL_REMOVABLE)
>    VDISK_READONLY implies a READ_ONLY_DIRECT_ACCESS_DEVICE
>
>    'Standard' disks usually set no flags (i.e. media is RW and not removable)
>    A CDROM will set VDISK_CDROM | VDISK_READONLY, to indicate the media is RO
>    and removable.
>
> STOR_FEATURE_FULL_PNP_DEVICE_CAPABILITIES must be set, otherwise StorPort will
> not use the values provided for EjectSupported and SurpriseRemovalOK in the
> STOR_DEVICE_CAPABILITIES_EX structure. Without this, CM_DEVCAP_EJECTSUPPORTED
> and CM_DEVCAP_SURPRISEREMOVALOK are left unchanged, and prevents a non-removable
> device from identifying correctly as non-removable.
>
> Signed-off-by: Owen Smith <owen.smith@xxxxxxxxxx>
Acked-by: Paul Durrant <paul@xxxxxxx>