new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index 9f68a37..743c7c2 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -159,7 +159,7 @@
 	struct inode *inode;
 
 	if (f) {
-		inode = f->f_path.dentry->d_inode;
+		inode = file_inode(f);
 		sbi = autofs4_sbi(inode->i_sb);
 	}
 	return sbi;