Re: [PATCH V2] target: fix the pgr/alua_support_store functions

[Bodo Stroesser <bostroesser@gmail.com>]

On 06.09.21 17:18, Maurizio Lombardi wrote:
> Commit 356ba2a8bc8d ("scsi: target: tcmu: Make pgr_support and
> alua_support attributes writable")
> introduced support for changeable alua_support and pgr_support
> target attributes. They can only be changed
> if the backstore is user-backed, otherwise the kernel returns -EINVAL.
> 
> This triggers a warning in the targetcli/rtslib code when performing
> a target restore that includes non-userbacked backstores:
> 
> #targetctl restore
> Storage Object block/storage1: Cannot set attribute alua_support:
> [Errno 22] Invalid argument, skipped
> Storage Object block/storage1: Cannot set attribute pgr_support:
> [Errno 22] Invalid argument, skipped
> 
> Fix this warning by returning an error code only if we are really
> going to flip the PGR/ALUA bit in the transport_flags field,
> otherwise we'll do nothing and return success.
> 
> Return ENOSYS instead of EINVAL if the pgr/alua attributes
> can't be changed, this way it'll be possible for userspace to understand
> if the operation failed because an invalid value has been passed
> to strtobool() or because the attributes are fixed.
> 
> Fixes: 356ba2a8bc8d ("scsi: target: tcmu: Make pgr_support and alua_support attributes writable")
> 
> v2: replace EOPNOTSUPP with ENOSYS
> 
> Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
> ---

Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>