Commit a534ecb0 authored by NeilBrown's avatar NeilBrown Committed by Anna Schumaker
Browse files

NFSv4: add cl_root_cred for use when machine cred is not available. 



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: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 1a80810f

fs/nfs/client.c

+2 −0
Original line number Diff line number Diff line
@@ -248,6 +248,8 @@ void nfs_free_client(struct nfs_client *clp) 


	if (clp->cl_machine_cred != NULL)

		put_rpccred(clp->cl_machine_cred);

	if (clp->cl_root_cred != NULL)

		put_rpccred(clp->cl_root_cred);



	put_net(clp->cl_net);

	put_nfs_version(clp->cl_nfs_mod);

fs/nfs/nfs4state.c

+12 −8
Original line number Diff line number Diff line
@@ -166,24 +166,28 @@ out: 


struct rpc_cred *nfs4_get_machine_cred_locked(struct nfs_client *clp)

{

	struct rpc_cred *cred = NULL;

	struct rpc_cred *cred = clp->cl_root_cred;



	if (clp->cl_machine_cred != NULL)

		cred = get_rpccred(clp->cl_machine_cred);

	if (!cred)

		cred = clp->cl_machine_cred;

	if (cred)

		return get_rpccred(cred);

	return cred;

}



static void nfs4_root_machine_cred(struct nfs_client *clp)

{

	struct rpc_cred *cred, *new;

	struct rpc_cred *new;



	new = rpc_lookup_machine_cred(NULL);

	spin_lock(&clp->cl_lock);

	cred = clp->cl_machine_cred;

	clp->cl_machine_cred = new;

	if (clp->cl_root_cred == NULL) {

		clp->cl_root_cred = new;

		new = NULL;

	}

	spin_unlock(&clp->cl_lock);

	if (cred != NULL)

		put_rpccred(cred);

	if (new != NULL)

		put_rpccred(new);

}



static struct rpc_cred *

include/linux/nfs_fs_sb.h

+1 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ struct nfs_client { 


	u32			cl_minorversion;/* NFSv4 minorversion */

	struct rpc_cred		*cl_machine_cred;

	struct rpc_cred		*cl_root_cred;	/* Use when machine_cred is ineffective */



#if IS_ENABLED(CONFIG_NFS_V4)

	struct list_head	cl_ds_clients; /* auth flavor data servers */

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