Date: Fri, 20 Nov 2009 18:11:07 +0100
From: Jan Blunck <jblunck@suse.de>
To: Jamie Lokier <jamie@shareable.org>
Cc: linux-fsdevel@vger.kernel.org, Christoph Hellwig <hch@infradead.org>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Linux-Kernel Mailinglist <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>, jkacur@redhat.com,
       Arnd Bergmann <arnd@arndb.de>,
       =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>,
       Alexander Viro <viro@zeniv.linux.org.uk>,
       Matthew Wilcox <matthew@wil.cx>
Subject: Re: [PATCH 01/15] Introduce noop_llseek()
Message-ID: <20091120171107.GZ21750@bolzano.suse.de>
References: <1258735245-25826-1-git-send-email-jblunck@suse.de> <1258735245-25826-2-git-send-email-jblunck@suse.de> <20091120170547.GF20634@shareable.org>
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On Fri, Nov 20, Jamie Lokier wrote:

> Jan Blunck wrote:
> > The noop_llseek() is a llseek() operation that filesystems can use that
> > don't want to support seeking (leave the file->f_pos untouched) but still
> > want to let the syscall itself to succeed.
> 
> This is weird behaviour: if you want to allow llseek() to succeed but
> don't really support seeking, why does the device even care about the
> value of file->f_pos?

The device itself does not care about it but it is userspace that is expecting
the seek to succeed. There is a comment in osst that at least there seems to
be a borken version of tar that wants to seek on the device even it that does
not have any effect.

Regards,
	Jan

-- 
Jan Blunck <jblunck@suse.de>
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