NFS: Add nfs4_unique_id boot parameter

An optional boot parameter is introduced to allow client
administrators to specify a string that the Linux NFS client can
insert into its nfs_client_id4 id string, to make it both more
globally unique, and to ensure that it doesn't change even if the
client's nodename changes.

If this boot parameter is not specified, the client's nodename is
used, as before.

Client installation procedures can create a unique string (typically,
a UUID) which remains unchanged during the lifetime of that client
instance.  This works just like creating a UUID for the label of the
system's root and boot volumes.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ad7e2e5088c1..396a1e66e0ae 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1719,6 +1719,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         will be autodetected by the client, and it will fall
                         back to using the idmapper.
                         To turn off this behaviour, set the value to '0'.
+        nfs.nfs4_unique_id=
+                        [NFS4] Specify an additional fixed unique ident-
+                        ification string that NFSv4 clients can insert into
+                        their nfs_client_id4 string.  This is typically a
+                        UUID that is generated at system install time.
 
         nfs.send_implementation_id =
                         [NFSv4.1] Send client implementation identification