From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 1/6] xfs: mmap write/read leaves bad state on pages Date: Thu, 21 Aug 2014 06:08:12 -0700 Message-ID: <20140821130812.GC1567@infradead.org> References: <1408597754-13526-1-git-send-email-david@fromorbit.com> <1408597754-13526-2-git-send-email-david@fromorbit.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, clm@fb.com, xfs@oss.sgi.com To: Dave Chinner Return-path: Content-Disposition: inline In-Reply-To: <1408597754-13526-2-git-send-email-david@fromorbit.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com List-Id: linux-fsdevel.vger.kernel.org On Thu, Aug 21, 2014 at 03:09:09PM +1000, Dave Chinner wrote: > From: Dave Chinner > > generic/263 is failing fsx at this point with a page spanning > EOF that cannot be invalidated. The operations are: > > 1190 mapwrite 0x52c00 thru 0x5e569 (0xb96a bytes) > 1191 mapread 0x5c000 thru 0x5d636 (0x1637 bytes) > 1192 write 0x5b600 thru 0x771ff (0x1bc00 bytes) > > where 1190 extents EOF from 0x54000 to 0x5e569. When the direct IO > write attempts to invalidate the cached page over this range, it > fails with -EBUSY and so we fire this assert: > > XFS: Assertion failed: ret < 0 || ret == count, file: fs/xfs/xfs_file.c, line: 676 > > because the kernel is trying to fall back to buffered IO on the > direct IO path (which XFS does not do). > > The real question is this: Why can't that page be invalidated after > it has been written to disk an cleaned? > > Well, there's data on the first two buffers in the page (1k block > size, 4k page), but the third buffer on the page (i.e. beyond EOF) > is failing drop_buffers because it's bh->b_state == 0x3, which is > BH_Uptodate | BH_Dirty. IOWs, there's dirty buffers beyond EOF. Say > what? > > OK, set_buffer_dirty() is called on all buffers from > __set_page_buffers_dirty(), regardless of whether the buffer is > beyond EOF or not, which means that when we get to ->writepage, > we have buffers marked dirty beyond EOF that we need to clean. > So, we need to implement our own .set_page_dirty method that > doesn't dirty buffers beyond EOF. Shouldn't this be fixed in __set_page_buffers_dirty itself? This doesn't seem an XFS-specific issue. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs