new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3d4fb81..4df78dd 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -553,7 +553,7 @@
 	va_list args;
 	struct va_format vaf;
 	struct ext4_super_block *es;
-	struct inode *inode = file->f_dentry->d_inode;
+	struct inode *inode = file_inode(file);
 	char pathname[80], *path;
 
 	es = EXT4_SB(inode->i_sb)->s_es;