From: Jamie Lokier <jamie@shareable.org>
To: Matt Helsley <matthltc@us.ibm.com>
Cc: Andreas Dilger <adilger@sun.com>,
Oren Laadan <orenl@cs.columbia.edu>,
linux-fsdevel@vger.kernel.org,
containers@lists.linux-foundation.org
Subject: Re: [C/R v20][PATCH 38/96] c/r: dump open file descriptors
Date: Sun, 21 Mar 2010 17:27:03 +0000 [thread overview]
Message-ID: <20100321172703.GC4174@shareable.org> (raw)
In-Reply-To: <20100320044310.GC2887@count0.beaverton.ibm.com>
Matt Helsley wrote:
> > That said, if the intent is to allow the restore to be done on
> > another node with a "similar" filesystem (e.g. created by rsync/node
> > image), instead of having a coherent distributed filesystem on all
> > of the nodes then the filename makes sense.
>
> Yes, this is the intent.
I would worry about programs which are using files which have been
deleted, renamed, or (very common) renamed-over by another process
after being opened, as there's a good chance they will successfully
open the wrong file after c/r, and corrupt state from then on.
This can be avoided by ensuring every checkpointed application is
specially "c/r aware", but that makes the feature a lot less
attractive, as well as uncomfortably unsafe to use on arbitrary
processes. Ideally, c/r would fail on some types of process
(e.g. using sockets), but at least fail in a safe way that does not
lead to quiet data corruption.
-- Jamie
next prev parent reply other threads:[~2010-03-21 17:27 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-19 0:59 [C/R v20][PATCH 00/96] Linux Checkpoint-Restart - v20 Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 20/96] c/r: make file_pos_read/write() public Oren Laadan
2010-03-22 6:31 ` Nick Piggin
2010-03-23 0:12 ` Oren Laadan
2010-03-23 0:43 ` Nick Piggin
2010-03-23 0:56 ` Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 37/96] c/r: introduce new 'file_operations': ->checkpoint, ->collect() Oren Laadan
2010-03-22 6:34 ` Nick Piggin
2010-03-22 10:16 ` Matt Helsley
2010-03-22 11:00 ` Nick Piggin
2010-03-19 0:59 ` [C/R v20][PATCH 38/96] c/r: dump open file descriptors Oren Laadan
2010-03-19 23:19 ` Andreas Dilger
2010-03-20 4:43 ` Matt Helsley
2010-03-21 17:27 ` Jamie Lokier [this message]
2010-03-21 19:40 ` Serge E. Hallyn
2010-03-21 20:58 ` Daniel Lezcano
2010-03-21 21:36 ` Oren Laadan
[not found] ` <4BA6914D.8040007-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2010-03-21 23:31 ` xing lin
2010-03-22 8:40 ` Daniel Lezcano
2010-03-22 2:12 ` Matt Helsley
2010-03-22 13:51 ` Jamie Lokier
2010-03-22 23:18 ` Andreas Dilger
2010-03-22 1:06 ` Matt Helsley
2010-03-22 2:20 ` Jamie Lokier
2010-03-22 3:37 ` Matt Helsley
2010-03-22 14:13 ` Jamie Lokier
2010-03-22 2:55 ` Serge E. Hallyn
[not found] ` <1268960401-16680-4-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2010-03-22 10:30 ` Nick Piggin
2010-03-22 13:22 ` Matt Helsley
2010-03-22 13:38 ` Nick Piggin
2010-03-19 0:59 ` [C/R v20][PATCH 39/96] c/r: restore " Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 40/96] c/r: introduce method '->checkpoint()' in struct vm_operations_struct Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 44/96] c/r: add generic '->checkpoint' f_op to ext fses Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 45/96] c/r: add generic '->checkpoint()' f_op to simple devices Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 46/96] c/r: add checkpoint operation for opened files of generic filesystems Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 50/96] splice: export pipe/file-to-pipe/file functionality Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 51/96] c/r: support for open pipes Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 52/96] c/r: checkpoint and restore FIFOs Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 53/96] c/r: refuse to checkpoint if monitoring directories with dnotify Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 66/96] c/r: restore file->f_cred Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 82/96] c/r: checkpoint/restart epoll sets Oren Laadan
2010-03-19 0:59 ` [C/R v20][PATCH 83/96] c/r: checkpoint/restart eventfd Oren Laadan
2010-03-19 1:00 ` [C/R v20][PATCH 84/96] c/r: restore task fs_root and pwd (v3) Oren Laadan
2010-03-19 1:00 ` [C/R v20][PATCH 85/96] c/r: preliminary support mounts namespace Oren Laadan
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