coredump: accept any write method

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

fs/coredump.c

@@ -657,7 +657,7 @@ void do_coredump(const siginfo_t *siginfo)
 		 */
 		if (!uid_eq(inode->i_uid, current_fsuid()))
 			goto close_fail;
-		if (!cprm.file->f_op->write)
+		if (!(cprm.file->f_mode & FMODE_CAN_WRITE))
 			goto close_fail;
 		if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
 			goto close_fail;