nfsv4/pnfs: use the MDS authflavor for data server connections

When a pNFS client connects to an NFSv4.1 data server, the EXCHANGE_ID
is always attempted with RPCSEC_GSS krb5i first, even if the auth flavor
with the MDS is AUTH_SYS. On a host that runs rpc.gssd but has no usable
machine credential, every first contact with a data server therefore
upcalls to rpc.gssd before falling back to AUTH_SYS.

As nfs4_discover_server_trunking is serialized by nfs_clid_init_mutex
such an extra upcall creates a backlog of DS connections when many files
accessed in parallel.

Pass the authflavor of the MDS lease to nfs4_alloc_client() and skip
the krb5i attempt if the MDS already ended up with AUTH_SYS. Nothing
changes for the MDS itself, or for data servers of an MDS whose lease
was established with krb5i.

Fixes: 4edaa308888b ("NFS: Use "krb5i" to establish NFSv4 state whenever possible")
Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: Anna Schumaker <anna.schumaker@hammerspace.com>

0 files changed, 0 insertions, 0 deletions