From: Miklos Szeredi <mszeredi@suse.cz>

Register NFS' backing_dev_info under sysfs with the name "nfs-MAJOR:MINOR"

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/nfs/super.c |   27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff -puN fs/nfs/super.c~mm-bdi-expose-the-bdi-object-in-sysfs-for-nfs fs/nfs/super.c
--- a/fs/nfs/super.c~mm-bdi-expose-the-bdi-object-in-sysfs-for-nfs
+++ a/fs/nfs/super.c
@@ -1458,6 +1458,12 @@ static int nfs_compare_super(struct supe
 	return nfs_compare_mount_options(sb, server, mntflags);
 }
 
+static int nfs_bdi_register(struct nfs_server *server)
+{
+	return bdi_register(&server->backing_dev_info, NULL, "nfs-%u:%u",
+			    MAJOR(server->s_dev), MINOR(server->s_dev));
+}
+
 static int nfs_get_sb(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
 {
@@ -1498,6 +1504,10 @@ static int nfs_get_sb(struct file_system
 	if (s->s_fs_info != server) {
 		nfs_free_server(server);
 		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error)
+			goto error_splat_super;
 	}
 
 	if (!s->s_root) {
@@ -1538,6 +1548,7 @@ static void nfs_kill_super(struct super_
 {
 	struct nfs_server *server = NFS_SB(s);
 
+	bdi_unregister(&server->backing_dev_info);
 	kill_anon_super(s);
 	nfs_free_server(server);
 }
@@ -1582,6 +1593,10 @@ static int nfs_xdev_get_sb(struct file_s
 	if (s->s_fs_info != server) {
 		nfs_free_server(server);
 		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error)
+			goto error_splat_super;
 	}
 
 	if (!s->s_root) {
@@ -1872,6 +1887,10 @@ static int nfs4_get_sb(struct file_syste
 	if (s->s_fs_info != server) {
 		nfs_free_server(server);
 		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error)
+			goto error_splat_super;
 	}
 
 	if (!s->s_root) {
@@ -1957,6 +1976,10 @@ static int nfs4_xdev_get_sb(struct file_
 	if (s->s_fs_info != server) {
 		nfs_free_server(server);
 		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error)
+			goto error_splat_super;
 	}
 
 	if (!s->s_root) {
@@ -2036,6 +2059,10 @@ static int nfs4_referral_get_sb(struct f
 	if (s->s_fs_info != server) {
 		nfs_free_server(server);
 		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error)
+			goto error_splat_super;
 	}
 
 	if (!s->s_root) {
_