From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nick Piggin <npiggin@suse.de>
Subject: [rfc][patch] fs: mntput might sleep
Date: Thu, 18 Mar 2010 00:28:20 +1100
Message-ID: <20100317132820.GH2869@laptop>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: Al Viro <viro@ZenIV.linux.org.uk>
To: linux-fsdevel@vger.kernel.org
Return-path: <linux-fsdevel-owner@vger.kernel.org>
Received: from cantor2.suse.de ([195.135.220.15]:42276 "EHLO mx2.suse.de"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1751011Ab0CQN2Y (ORCPT <rfc822;linux-fsdevel@vger.kernel.org>);
	Wed, 17 Mar 2010 09:28:24 -0400
Content-Disposition: inline
Sender: linux-fsdevel-owner@vger.kernel.org
List-ID: <linux-fsdevel.vger.kernel.org>

I missed this once or twice, so can we put might_sleep check into
mntput?  Or does anyone call it from atomic context to drop a known
not-last reference? (if so then maybe the caller could be rewritten).
--
Index: linux-2.6/include/linux/mount.h
===================================================================
--- linux-2.6.orig/include/linux/mount.h
+++ linux-2.6/include/linux/mount.h
@@ -113,6 +113,8 @@ extern int __mnt_is_readonly(struct vfsm
 static inline void mntput(struct vfsmount *mnt)
 {
 	if (mnt) {
+		might_sleep();
+
 		mnt->mnt_expiry_mark = 0;
 		mntput_no_expire(mnt);
 	}