From: Andy Adamson <andros@umich.edu>
Date: Fri, 18 May 2007 16:52:46 -0400
NFSv4: Handle NFS4ERR_WRONGSEC in nfs4_proc_lookup

The first time through the wrongsec handler, setup the ex_list via a secinfo
call. The existance of ex_list signals to skip setup and try the next flavor
on the list, which will only occur if the server secinfo list is incorret, or
if we are trying a list of flavors (from mount) on a PUTROOTFH/PUTFH WRONGSEC.

Free the wrongsec handler resources upon success. NOTE: future patches will
pass a successful flavor to nfs_clone_server() for new fsid nfs_server setup.

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

 fs/nfs/nfs4_fs.h  |    3 +++
 fs/nfs/nfs4proc.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 fs/nfs/nfs4xdr.c  |    4 ----
 3 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 3ff47de..f85f2b2 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -168,6 +168,9 @@ extern ssize_t nfs4_getxattr(struct dentry *, const char *, void *, size_t);
 extern int nfs4_setxattr(struct dentry *, const char *, const void *, size_t, int);
 extern ssize_t nfs4_listxattr(struct dentry *, char *, size_t);
 
+/* client.c */
+extern void nfs4_shutdown_wrongsec(struct nfs4_exception *);
+extern int nfs4_clnt_try_next_flavor(struct nfs_server *, struct nfs4_exception *);
 
 /* nfs4proc.c */
 extern int nfs4_map_errors(int err);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 8df5c0e..afeb5bf 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -65,6 +65,8 @@ static int nfs4_async_handle_error(struct rpc_task *, const struct nfs_server *)
 static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry);
 static int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct nfs4_exception *exception);
 static int nfs4_wait_clnt_recover(struct rpc_clnt *clnt, struct nfs_client *clp);
+int nfs4_proc_secinfo(struct nfs_server *, struct nfs_fh *, struct qstr *, struct nfs4_secinfo_res *);
+
 
 /* Prevent leaks of NFSv4 errors into userland */
 int nfs4_map_errors(int err)
@@ -1601,6 +1603,8 @@ static int _nfs4_proc_lookup(struct inode *dir, struct qstr *name,
 		.rpc_resp = &res,
 	};
 	
+	if (exc->ex_cred)
+		msg.rpc_cred = exc->ex_cred;
 	nfs_fattr_init(fattr);
 	
 	dprintk("NFS call  lookup %s\n", name->name);
@@ -2752,6 +2756,37 @@ static int nfs4_delay(struct rpc_clnt *clnt, long *timeout)
 	return res;
 }
 
+static int nfs4_wrongsec(struct nfs4_exception *exc, struct nfs_server *server)
+{
+	int err = -EACCES;
+
+	dprintk("--> nfs4_wrongsec\n");
+
+	if (exc->ex_list)
+		goto try;
+	switch(exc->ex_info.op) {
+		case OP_LOOKUP:
+			err = -ENOMEM;
+			exc->ex_list = kzalloc(sizeof(*exc->ex_list), GFP_KERNEL);
+			if (!exc->ex_list)
+				goto out;
+			err = nfs4_proc_secinfo(server, exc->ex_info.fh,
+						exc->ex_info.name,
+						exc->ex_list);
+			break;
+		default:
+			printk("ERROR: %s() don't know what to do for op=%d\n",                                __FUNCTION__, exc->ex_info.op);
+			break;
+	}
+	if (err != 0)
+		goto out;
+try:
+	err = nfs4_clnt_try_next_flavor(server, exc);
+out:
+	dprintk("<-- nfs4_wrongsec error %d\n", err);
+	return err;
+}
+
 /* This is the error handling routine for processes that are allowed
  * to sleep.
  */
@@ -2763,6 +2798,8 @@ static int nfs4_handle_exception(const struct nfs_server *server, int errorcode,
 	exception->retry = 0;
 	switch(errorcode) {
 		case 0:
+			if (exception->ex_list)
+				nfs4_shutdown_wrongsec(exception);
 			return 0;
 		case -NFS4ERR_STALE_CLIENTID:
 		case -NFS4ERR_STALE_STATEID:
@@ -2780,6 +2817,11 @@ static int nfs4_handle_exception(const struct nfs_server *server, int errorcode,
 				break;
 		case -NFS4ERR_OLD_STATEID:
 			exception->retry = 1;
+			break;
+		case -NFS4ERR_WRONGSEC:
+			ret = nfs4_wrongsec(exception, (struct nfs_server *)server);
+			if (ret == 0)
+				exception->retry = 1;
 	}
 	/* We failed to handle the error */
 	return nfs4_map_errors(ret);
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index e561cc8..4eb8a59 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -4636,10 +4636,6 @@ static struct {
 	{ NFS4ERR_SYMLINK,	ELOOP		},
 	{ NFS4ERR_OP_ILLEGAL,	EOPNOTSUPP	},
 	{ NFS4ERR_DEADLOCK,	EDEADLK		},
-	{ NFS4ERR_WRONGSEC,	EPERM		}, /* FIXME: this needs
-						    * to be handled by a
-						    * middle-layer.
-						    */
 	{ -1,			EIO		}
 };