diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h
index 9f9cadbfbd7a..64f693d355ad 100644
--- a/fs/autofs/autofs_i.h
+++ b/fs/autofs/autofs_i.h
@@ -42,6 +42,8 @@
 #endif
 #define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__
 
+extern struct file_system_type autofs_fs_type;
+
 /*
  * Unified info structure.  This is pointed to by both the dentry and
  * inode structures.  Each file in the filesystem has an instance of this
@@ -126,8 +128,7 @@ struct autofs_sb_info {
 
 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
 {
-	return sb->s_magic != AUTOFS_SUPER_MAGIC ?
-		NULL : (struct autofs_sb_info *)(sb->s_fs_info);
+	return (struct autofs_sb_info *)(sb->s_fs_info);
 }
 
 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)
diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c
index 86eafda4a652..752983aafb84 100644
--- a/fs/autofs/dev-ioctl.c
+++ b/fs/autofs/dev-ioctl.c
@@ -151,22 +151,6 @@ out:
 	return err;
 }
 
-/*
- * Get the autofs super block info struct from the file opened on
- * the autofs mount point.
- */
-static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f)
-{
-	struct autofs_sb_info *sbi = NULL;
-	struct inode *inode;
-
-	if (f) {
-		inode = file_inode(f);
-		sbi = autofs_sbi(inode->i_sb);
-	}
-	return sbi;
-}
-
 /* Return autofs dev ioctl version */
 static int autofs_dev_ioctl_version(struct file *fp,
 				    struct autofs_sb_info *sbi,
@@ -658,6 +642,8 @@ static int _autofs_dev_ioctl(unsigned int command,
 	if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
 	    cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
 	    cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
+		struct super_block *sb;
+
 		fp = fget(param->ioctlfd);
 		if (!fp) {
 			if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
@@ -666,12 +652,13 @@ static int _autofs_dev_ioctl(unsigned int command,
 			goto out;
 		}
 
-		sbi = autofs_dev_ioctl_sbi(fp);
-		if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
+		sb = file_inode(fp)->i_sb;
+		if (sb->s_type != &autofs_fs_type) {
 			err = -EINVAL;
 			fput(fp);
 			goto out;
 		}
+		sbi = autofs_sbi(sb);
 
 		/*
 		 * Admin needs to be able to set the mount catatonic in
diff --git a/fs/autofs/init.c b/fs/autofs/init.c
index 79ae07d9592f..c0c1db2cc6ea 100644
--- a/fs/autofs/init.c
+++ b/fs/autofs/init.c
@@ -16,7 +16,7 @@ static struct dentry *autofs_mount(struct file_system_type *fs_type,
 	return mount_nodev(fs_type, flags, data, autofs_fill_super);
 }
 
-static struct file_system_type autofs_fs_type = {
+struct file_system_type autofs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "autofs",
 	.mount		= autofs_mount,