On 13 Aug 2025, at 5:00, Anthony Iliopoulos wrote:
> When the client max_resp_sz is larger than what the server encodes in
> its reply, the nfs4_verify_back_channel_attrs() check fails and this
> causes nfs4_proc_create_session() to fail, in cases where the client
> page size is larger than that of the server and the server does not want
> to negotiate upwards.
>
> While this is not a problem with the linux nfs server that will reflect
> the proposed value in its reply irrespective of the local page size,
> other nfs server implementations may insist on their own max_resp_sz
> value, which could be smaller.
>
> Fix this by accepting smaller max_resp_sz values from the server, as
> this does not violate the protocol. The server is allowed to decrease
> but not increase proposed the size, and as such values smaller than the
> client-proposed ones are valid.
>
> Fixes: 43c2e885be25 ("nfs4: fix channel attribute sanity-checks")
> Signed-off-by: Anthony Iliopoulos <ailiop@xxxxxxxx>
Reviewed-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
Ben
