From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Dave Chinner <david@fromorbit.com>
Cc: Jiri Kosina <jikos@kernel.org>,
Alan Stern <stern@rowland.harvard.edu>,
Pavel Machek <pavel@ucw.cz>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@lst.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>, Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-pm@vger.kernel.org
Subject: Re: [PATCH 0/3] PM, vfs: use filesystem freezing instead of kthread freezer
Date: Tue, 03 Nov 2015 05:06:01 +0100 [thread overview]
Message-ID: <2254911.sCQ2smOA47@vostro.rjw.lan> (raw)
In-Reply-To: <20151103001053.GL10656@dastard>
On Tuesday, November 03, 2015 11:10:53 AM Dave Chinner wrote:
> On Mon, Nov 02, 2015 at 03:43:07AM +0100, Rafael J. Wysocki wrote:
> > I guess it may also helps to address the case when a device is removed from a
> > suspended system, written to on another system in the meantime and inserted
> > back into the (still suspended) original system which then is resumed. Today
> > this is an almost guaranteed data corruption scenario, but if the filesystem in
> > question is properly frozen during suspend, the driver should be able to detect
> > superblock changes during unfreeze.
>
> Never going to work. There is no guarantee that a write to a
> filesystem by a third party device is going to change the superblock
> (or any metadata in the rest of the filesystem) in any detectable
> way. Hence freezing filesystems will not prevent Bad Things
> Happening if you do this while your system is suspended.
OK, thanks for the clarification.
Cheers,
Rafael
next prev parent reply other threads:[~2015-11-03 3:36 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-30 13:47 Jiri Kosina
2015-10-30 13:47 ` [PATCH 1/3] power, vfs: move away from PF_KTHREAD freezing in favor of fs freezing Jiri Kosina
2015-10-30 14:04 ` kbuild test robot
2015-10-31 8:55 ` Oliver Neukum
2015-11-02 3:01 ` Neil Brown
2015-11-02 7:54 ` yalin wang
2015-11-02 11:05 ` Jiri Kosina
2015-10-30 13:47 ` [PATCH 2/3] freezer: get rid of the kthread freezer Jiri Kosina
2015-10-30 14:08 ` kbuild test robot
2015-10-30 14:12 ` kbuild test robot
2015-10-30 13:48 ` [PATCH 3/3] freezer: warn if anyone is trying to use freezer on kthreads Jiri Kosina
2015-10-30 15:29 ` [PATCH 0/3] PM, vfs: use filesystem freezing instead of kthread freezer Alan Stern
2015-10-30 17:44 ` Pavel Machek
2015-10-30 19:40 ` Jiri Kosina
2015-10-30 20:41 ` Alan Stern
2015-10-30 21:17 ` Jiri Kosina
2015-10-31 3:15 ` Rafael J. Wysocki
2015-10-31 8:19 ` Jiri Kosina
2015-11-02 2:43 ` Rafael J. Wysocki
2015-11-02 10:45 ` Jiri Kosina
2015-11-02 11:00 ` Oliver Neukum
2015-11-02 15:18 ` Alan Stern
2015-11-03 0:10 ` Dave Chinner
2015-11-03 4:06 ` Rafael J. Wysocki [this message]
2015-11-03 9:31 ` Jan Kara
2015-11-03 21:33 ` Rafael J. Wysocki
2015-10-31 16:01 ` Alan Stern
2015-10-31 15:56 ` Alan Stern
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