new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ext2/ioctl.c b/fs/ext2/ioctl.c
index 2de655f..5d46c09 100644
--- a/fs/ext2/ioctl.c
+++ b/fs/ext2/ioctl.c
@@ -19,7 +19,7 @@
 
 long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
-	struct inode *inode = filp->f_dentry->d_inode;
+	struct inode *inode = file_inode(filp);
 	struct ext2_inode_info *ei = EXT2_I(inode);
 	unsigned int flags;
 	unsigned short rsv_window_size;