From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [BUG] ext2/3/4: dio reads stale data when we do some append dio writes Date: Tue, 19 Nov 2013 03:01:47 -0800 Message-ID: <20131119110147.GA3323@infradead.org> References: <20131119095302.GA4534@gmail.com> <20131119102235.GA5010@infradead.org> <20131119104508.GA4630@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org Return-path: Content-Disposition: inline In-Reply-To: <20131119104508.GA4630@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Tue, Nov 19, 2013 at 06:45:08PM +0800, Zheng Liu wrote: > BTW, that would be great if you could give me some comments about this > problem itself. Is it a generic problem in vfs? Or just a feature by > design? It seems like a fundamental issue with ext4 (and most older Linux filesystems) trying to do dio reads without locking out writers. If you have a shared/exclusive lock to protect dio reads against buffered or appending writers like XFS does this issue is properly prevented.