nfs: merge xdev and remote file_system_type

they are identical now...
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/internal.h

@@ -388,7 +388,7 @@ extern int nfs_wait_atomic_killable(atomic_t *p, unsigned int mode);
 /* super.c */
 extern const struct super_operations nfs_sops;
 extern struct file_system_type nfs_fs_type;
-extern struct file_system_type nfs_xdev_fs_type;
+extern struct file_system_type nfs_prepared_fs_type;
 #if IS_ENABLED(CONFIG_NFS_V4)
 extern struct file_system_type nfs4_referral_fs_type;
 #endif

fs/nfs/namespace.c

@@ -257,7 +257,7 @@ struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh,
 	if (IS_ERR(devname))
 		mnt = ERR_CAST(devname);
 	else
-		mnt = vfs_submount(dentry, &nfs_xdev_fs_type, devname, &mount_info);
+		mnt = vfs_submount(dentry, &nfs_prepared_fs_type, devname, &mount_info);
 
 	if (mount_info.server)
 		nfs_free_server(mount_info.server);

fs/nfs/nfs4super.c

@@ -18,19 +18,9 @@
 
 static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
 static void nfs4_evict_inode(struct inode *inode);
-static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *raw_data);
 static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *raw_data);
 
-static struct file_system_type nfs4_remote_fs_type = {
-	.owner		= THIS_MODULE,
-	.name		= "nfs4",
-	.mount		= nfs4_remote_mount,
-	.kill_sb	= nfs_kill_super,
-	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
-};
-
 struct file_system_type nfs4_referral_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "nfs4",
@@ -91,16 +81,6 @@ static void nfs4_evict_inode(struct inode *inode)
 	nfs_clear_inode(inode);
 }
 
-/*
- * Get the superblock for the NFS4 root partition
- */
-static struct dentry *
-nfs4_remote_mount(struct file_system_type *fs_type, int flags,
-		  const char *dev_name, void *info)
-{
-	return nfs_fs_mount_common(flags, dev_name, info);
-}
-
 struct nfs_referral_count {
 	struct list_head list;
 	const struct task_struct *task;
@@ -194,7 +174,7 @@ static struct dentry *do_nfs4_mount(struct nfs_server *server, int flags,
 	else
 		snprintf(root_devname, len, "%s:/", hostname);
 	info->server = server;
-	root_mnt = vfs_kern_mount(&nfs4_remote_fs_type, flags, root_devname, info);
+	root_mnt = vfs_kern_mount(&nfs_prepared_fs_type, flags, root_devname, info);
 	if (info->server)
 		nfs_free_server(info->server);
 	info->server = NULL;

fs/nfs/super.c

@@ -293,7 +293,7 @@ static match_table_t nfs_vers_tokens = {
 	{ Opt_vers_err, NULL }
 };
 
-static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
+static struct dentry *nfs_prepared_mount(struct file_system_type *fs_type,
 		int flags, const char *dev_name, void *raw_data);
 
 struct file_system_type nfs_fs_type = {
@@ -306,13 +306,14 @@ struct file_system_type nfs_fs_type = {
 MODULE_ALIAS_FS("nfs");
 EXPORT_SYMBOL_GPL(nfs_fs_type);
 
-struct file_system_type nfs_xdev_fs_type = {
+struct file_system_type nfs_prepared_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "nfs",
-	.mount		= nfs_xdev_mount,
+	.mount		= nfs_prepared_mount,
 	.kill_sb	= nfs_kill_super,
 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
 };
+EXPORT_SYMBOL_GPL(nfs_prepared_fs_type);
 
 const struct super_operations nfs_sops = {
 	.alloc_inode	= nfs_alloc_inode,
@@ -2791,10 +2792,11 @@ void nfs_kill_super(struct super_block *s)
 EXPORT_SYMBOL_GPL(nfs_kill_super);
 
 /*
- * Clone an NFS2/3/4 server record on xdev traversal (FSID-change)
+ * Internal use only: mount_info is already set up by caller.
+ * Used for mountpoint crossings and for nfs4 root.
  */
 static struct dentry *
-nfs_xdev_mount(struct file_system_type *fs_type, int flags,
+nfs_prepared_mount(struct file_system_type *fs_type, int flags,
 		   const char *dev_name, void *raw_data)
 {
 	return nfs_fs_mount_common(flags, dev_name, raw_data);