From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: [RFC][PATCH 1/4][cr]: Add uid, euid params to f_modown() Date: Wed, 12 May 2010 18:05:13 +0100 Message-ID: <20100512170513.GD19314@shareable.org> References: <1273617500-13653-1-git-send-email-sukadev@linux.vnet.ibm.com> <1273617500-13653-2-git-send-email-sukadev@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Oren Laadan , Matt Helsley , serue@us.ibm.com, Containers , linux-fsdevel@vger.kernel.org To: Sukadev Bhattiprolu Return-path: Received: from mail2.shareable.org ([80.68.89.115]:47893 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751508Ab0ELRF1 (ORCPT ); Wed, 12 May 2010 13:05:27 -0400 Content-Disposition: inline In-Reply-To: <1273617500-13653-2-git-send-email-sukadev@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Sukadev Bhattiprolu wrote: > Checkpoint/restart of file-owner. > > Add uid, euid parameters to f_modown(). These parameters will be needed > when restarting an application (and hence restoring the file information), > from a checkpoint image. This is used to make sure I/O signals on sockets, ttys, devices and so on are delivered to a particular process. If any of those signals are lost when an event happens around the same time as c/r (for example, more data arriving on a pipe, a device becomes readable/writable, or room becoming available to write, or urgent data on a socket), a process depending on it can get stuck - unless the process knows that c/r happened, so it knows to call select() on all those fds after the c/r. Can you say if the c/r avoids that kind of race condition? Thanks, -- Jamie