From: David Woodhouse <dwmw2@infradead.org>
To: Ricard Wanderlof <ricard.wanderlof@axis.com>
Cc: Marco Braga <marco.braga@gmail.com>,
"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>
Subject: Re: JFFS2 losing files on mount
Date: Thu, 22 Jan 2009 15:03:39 +1100 [thread overview]
Message-ID: <1232597019.3921.2.camel@macbook.infradead.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0901211603040.12232@lnxricardw.se.axis.com>
On Wed, 2009-01-21 at 16:05 +0100, Ricard Wanderlof wrote:
>
> On Wed, 21 Jan 2009, Marco Braga wrote:
>
> > I am doing some power failure tests on an ARM7 based device using
> > JFFS2 on NAND flash and I am a bit disappointed by the early results.
> > ...
> > I'd like to hear your experiences. What do you think?
>
> We use JFFS2 on both an ARM9-platform and on our own CRIS platform. We
> never unmount the device in preparation for power down; when someone pulls
> the plug, the system just dies. While we do occasionally see warning
> messages about incomplete nodes during the next boot-up, we have never
> experienced anything as severe as you mention, and we have not lost any
> files on the JFFS2 filesystem either.
Is this on NAND, or NOR flash? On NAND flash, you do actually have to
have non-buggy userspace; if you don't use sync() or fsync()
appropriately then there may be data which aren't yet flushed to the
flash.
On NOR flash, we're a whole lot more tolerant of buggy userspace. Which
is what >99% of reports like Marco's turn out to be. Although we're
always interested in the possibility that it _does_ turn out to be a
real JFFS2 bug...
--
David Woodhouse Open Source Technology Centre
David.Woodhouse@intel.com Intel Corporation
next prev parent reply other threads:[~2009-01-22 4:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-21 9:29 JFFS2 losing files on mount Marco Braga
2009-01-21 15:05 ` Ricard Wanderlof
2009-01-22 4:03 ` David Woodhouse [this message]
2009-01-22 6:33 ` Ricard Wanderlof
2009-01-22 6:36 ` David Woodhouse
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