NFSv4 state management tries a root credential when no machine
credential is available, as can happen with kerberos.
It does this by replacing the cl_machine_cred with a root credential.
This means that any user of the machine credential needs to take
a lock while getting a reference to the machine credential, which is
a little cumbersome.
So introduce an explicit cl_root_cred, and never free either
credential until client shutdown. This means that no locking
is needed to reference these credentials. Future patches
will make use of this.
This is only a temporary addition. both cl_machine_cred and
cl_root_cred will disappear later in the series.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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