• Chuck Lever's avatar
    nfsd: Lower NFSv4.1 callback message size limit · 4500632f
    Chuck Lever authored
    The maximum size of a backchannel message on RPC-over-RDMA depends
    on the connection's inline threshold. Today that threshold is
    typically 1024 bytes, making the maximum message size 996 bytes.
    
    The Linux server's CREATE_SESSION operation checks that the size
    of callback Calls can be as large as 1044 bytes, to accommodate
    RPCSEC_GSS. Thus CREATE_SESSION fails if a client advertises the
    true message size maximum of 996 bytes.
    
    But the server's backchannel currently does not support RPCSEC_GSS.
    The actual maximum size it needs is much smaller. It is safe to
    reduce the limit to enable NFSv4.1 on RDMA backchannel operation.
    Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
    Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
    4500632f
auth_unix.c 5.68 KB