From: Andrew Morton Subject: Re: [RFC PATCH 0/3] Stop clearing uptodate flag on write IO error Date: Thu, 5 Jan 2012 14:16:06 -0800 Message-ID: <20120105141606.5e19a08b.akpm@linux-foundation.org> References: <1325774407-28531-1-git-send-email-jack@suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, Christoph Hellwig , Al Viro , LKML , Edward Shishkin , Linus Torvalds To: Jan Kara Return-path: In-Reply-To: <1325774407-28531-1-git-send-email-jack@suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, 5 Jan 2012 15:40:04 +0100 Jan Kara wrote: > > Hello, > > for mostly historical reasons we still clear buffer_uptodate flag on write > IO errors. I have long and strong memories of never being able to understand why we did that. > This is not only semantically wrong (buffer still has correct data > in it) but it also triggers warnings in mark_buffer_dirty when buffer is > written again which scares lots of users (as they tend to unplug USB sticks > too early). This patch series is an attempt to start solving the problem > by allowing filesystem to tell whether it wishes buffer_uptodate flag cleared > on write IO error. Ext2 is converted to use this as an example. Eventually > when all filesystems are converted, we can remove the condition. > > Do people think this is a desirable way to go? > Linus might have some thoughts.