vfs: Convert apparmorfs to use the new mount API

Convert the apparmorfs 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: John Johansen <john.johansen@canonical.com>
cc: apparmor@lists.ubuntu.com
cc: linux-security-module@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

security/apparmor/apparmorfs.c

@@ -23,6 +23,7 @@
 #include <linux/capability.h>
 #include <linux/rcupdate.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
 #include <linux/poll.h>
 #include <uapi/linux/major.h>
 #include <uapi/linux/magic.h>
@@ -136,7 +137,7 @@ static const struct super_operations aafs_super_ops = {
 	.show_path = aafs_show_path,
 };
 
-static int fill_super(struct super_block *sb, void *data, int silent)
+static int apparmorfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	static struct tree_descr files[] = { {""} };
 	int error;
@@ -149,16 +150,25 @@ static int fill_super(struct super_block *sb, void *data, int silent)
 	return 0;
 }
 
-static struct dentry *aafs_mount(struct file_system_type *fs_type,
-				 int flags, const char *dev_name, void *data)
+static int apparmorfs_get_tree(struct fs_context *fc)
 {
-	return mount_single(fs_type, flags, data, fill_super);
+	return get_tree_single(fc, apparmorfs_fill_super);
+}
+
+static const struct fs_context_operations apparmorfs_context_ops = {
+	.get_tree	= apparmorfs_get_tree,
+};
+
+static int apparmorfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &apparmorfs_context_ops;
+	return 0;
 }
 
 static struct file_system_type aafs_ops = {
 	.owner = THIS_MODULE,
 	.name = AAFS_NAME,
-	.mount = aafs_mount,
+	.init_fs_context = apparmorfs_init_fs_context,
 	.kill_sb = kill_anon_super,
 };