vfs: Convert configfs to use the new mount API

Convert the configfs filesystem to the new internal mount API as the old
one will be obsoleted and removed.  This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.

See Documentation/filesystems/mount_api.txt for more information.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Joel Becker <jlbec@evilplan.org>
cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/configfs/mount.c

@@ -27,6 +27,7 @@
 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/mount.h>
+#include <linux/fs_context.h>
 #include <linux/pagemap.h>
 #include <linux/init.h>
 #include <linux/slab.h>
@@ -66,7 +67,7 @@ static struct configfs_dirent configfs_root = {
 	.s_iattr	= NULL,
 };
 
-static int configfs_fill_super(struct super_block *sb, void *data, int silent)
+static int configfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct inode *inode;
 	struct dentry *root;
@@ -102,16 +103,25 @@ static int configfs_fill_super(struct super_block *sb, void *data, int silent)
 	return 0;
 }
 
-static struct dentry *configfs_do_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data)
+static int configfs_get_tree(struct fs_context *fc)
 {
-	return mount_single(fs_type, flags, data, configfs_fill_super);
+	return get_tree_single(fc, configfs_fill_super);
+}
+
+static const struct fs_context_operations configfs_context_ops = {
+	.get_tree	= configfs_get_tree,
+};
+
+static int configfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &configfs_context_ops;
+	return 0;
 }
 
 static struct file_system_type configfs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "configfs",
-	.mount		= configfs_do_mount,
+	.init_fs_context = configfs_init_fs_context,
 	.kill_sb	= kill_litter_super,
 };
 MODULE_ALIAS_FS("configfs");