new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/exofs/dir.c

@@ -242,7 +242,7 @@ static int
 exofs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 {
 	loff_t pos = filp->f_pos;
-	struct inode *inode = filp->f_path.dentry->d_inode;
+	struct inode *inode = file_inode(filp);
 	unsigned int offset = pos & ~PAGE_CACHE_MASK;
 	unsigned long n = pos >> PAGE_CACHE_SHIFT;
 	unsigned long npages = dir_pages(inode);