Add support for mapping NFSv4 remote user/group names into local

unix-style uid/gids.

Note that this makes use of the RPC client upcall mechanism
(rpc_pipefs) to notify a userland daemon that does the actual mapping.
The results are then cached in the kernel.
The userland daemon can be downloaded from the CITI NFSv4 page at

     http://www.citi.umich.edu/projects/nfsv4/

fs/nfs/Makefile

@@ -8,6 +8,7 @@ nfs-y 			:= dir.o file.o inode.o nfs2xdr.o pagelist.o \
 			   proc.o read.o symlink.o unlink.o write.o
 nfs-$(CONFIG_ROOT_NFS)	+= nfsroot.o mount_clnt.o      
 nfs-$(CONFIG_NFS_V3)	+= nfs3proc.o nfs3xdr.o
-nfs-$(CONFIG_NFS_V4)	+= nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o
+nfs-$(CONFIG_NFS_V4)	+= nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \
+			   idmap.o
 nfs-$(CONFIG_NFS_DIRECTIO) += direct.o
 nfs-objs		:= $(nfs-y)

fs/nfs/inode.c

@@ -33,6 +33,7 @@
 #include <linux/smp_lock.h>
 #include <linux/seq_file.h>
 #include <linux/mount.h>
+#include <linux/nfs_idmap.h>
 #include <linux/vfs.h>
 
 #include <asm/system.h>
@@ -152,6 +153,11 @@ nfs_put_super(struct super_block *sb)
 	struct nfs_server *server = NFS_SB(sb);
 	struct rpc_clnt	*rpc;
 
+#ifdef CONFIG_NFS_V4
+	if (server->idmap != NULL)
+		nfs_idmap_delete(server);
+#endif /* CONFIG_NFS_V4 */
+
 	if ((rpc = server->client) != NULL)
 		rpc_shutdown_client(rpc);
 
@@ -160,6 +166,7 @@ nfs_put_super(struct super_block *sb)
 	rpciod_down();		/* release rpciod */
 
 	destroy_nfsv4_state(server);
+
 	kfree(server->hostname);
 }
 
@@ -1362,11 +1369,16 @@ static int nfs4_fill_super(struct super_block *sb, struct nfs4_mount_data *data,
 	if (create_nfsv4_state(server, data))
 		goto out_shutdown;
 
+	if ((server->idmap = nfs_idmap_new(server)) == NULL)
+		printk(KERN_WARNING "NFS: couldn't start IDmap\n");
+
 	err = nfs_sb_init(sb);
 	if (err == 0)
 		return 0;
 	rpciod_down();
 	destroy_nfsv4_state(server);
+	if (server->idmap != NULL)
+		nfs_idmap_delete(server);
 out_shutdown:
 	rpc_shutdown_client(server->client);
 out_fail:

include/linux/nfs_fs_sb.h

@@ -36,6 +36,7 @@ struct nfs_server {
 	struct nfs4_client *	nfs4_state;	/* all NFSv4 state starts here */
 	unsigned long		lease_time;	/* in jiffies */
 	unsigned long		last_renewal;	/* in jiffies */
+	void                   *idmap;
 #endif
 };
 

include/linux/nfs_idmap.h

+/*
+ * include/linux/nfs_idmap.h
+ *
+ *  UID and GID to name mapping for clients.
+ *
+ *  Copyright (c) 2002 The Regents of the University of Michigan.
+ *  All rights reserved.
+ *
+ *  Marius Aamodt Eriksen <marius@umich.edu>
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions
+ *  are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *  3. Neither the name of the University nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef NFS_IDMAP_H
+#define NFS_IDMAP_H
+
+/* XXX from bits/utmp.h  */
+#define IDMAP_NAMESZ  128
+
+#define IDMAP_TYPE_USER  0
+#define IDMAP_TYPE_GROUP 1
+
+#define IDMAP_CONV_IDTONAME 0
+#define IDMAP_CONV_NAMETOID 1
+
+#define IDMAP_STATUS_INVALIDMSG 0x01
+#define IDMAP_STATUS_AGAIN      0x02
+#define IDMAP_STATUS_LOOKUPFAIL 0x04
+#define IDMAP_STATUS_SUCCESS    0x08
+
+struct idmap_msg {
+	u_int8_t  im_type;
+	u_int8_t  im_conv;
+	char      im_name[IDMAP_NAMESZ];
+	u_int32_t im_id;
+	u_int8_t  im_status;
+};
+
+#ifdef __KERNEL__
+void      *nfs_idmap_new(struct nfs_server *);
+void       nfs_idmap_delete(struct nfs_server *);
+int        nfs_idmap_id(struct nfs_server *, u_int8_t, char *, u_int,  uid_t *);
+int        nfs_idmap_name(struct nfs_server *, u_int8_t, uid_t, char *, u_int *);
+#endif /* __KERNEL__ */
+
+#endif /* NFS_IDMAP_H */