From: Andy Adamson <andros@umich.edu>
Date: Fri, 18 May 2007 16:52:41 -0400
NFSv4: Add a helper to return the next untried security flavor

Helper function for NFS4ERR_WRONGSEC handler
Returns RPC_AUTH_MAXFLAVOR when all flavors have been tried.

Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---

 fs/nfs/client.c  |   29 +++++++++++++++++++++++++++++
 fs/nfs/nfs4_fs.h |    1 +
 2 files changed, 30 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 881fa49..eb03f5f 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -1102,6 +1102,35 @@ error:
 	return ERR_PTR(error);
 }
 
+/*
+ * Return the next untried security flavor or RPC_AUTH_MAXFLAVOR
+ * when all flavors have been tried.
+ */
+static rpc_authflavor_t nfs4_next_flavor(struct nfs4_exception *exc,
+			          rpc_authflavor_t cur_flavor)
+{
+	struct nfs4_secinfo_res *sec;
+	rpc_authflavor_t ret = RPC_AUTH_MAXFLAVOR;
+	int i;
+
+	dprintk("-->nfs4_next_flavor\n");
+	sec = exc->ex_list;
+	for (i = 0; i < sec->fl_num; i++){
+
+		/* Skip flavors that have been tried. */
+		if (sec->flavors[i] == RPC_AUTH_MAXFLAVOR)
+			continue;
+
+		/* Try this flavor */
+		ret = sec->flavors[i];
+		sec->flavors[i] = RPC_AUTH_MAXFLAVOR;
+		goto out;
+	}
+out:
+	dprintk("<-- nfs4_next_flavor() error %d\n", ret);
+	return ret;
+}
+
 #endif /* CONFIG_NFS_V4 */
 
 /*
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index cf3a17e..9215b66 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -143,6 +143,7 @@ struct nfs4_state {
 struct nfs4_exception {
 	long timeout;
 	int retry;
+	struct nfs4_secinfo_res *ex_list;
 };
 
 struct nfs4_state_recovery_ops {