From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:37564 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755101AbcI2Ud2 (ORCPT ); Thu, 29 Sep 2016 16:33:28 -0400 Date: Thu, 29 Sep 2016 13:33:20 -0700 From: "Darrick J. Wong" To: Christoph Hellwig Cc: xfs@oss.sgi.com, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org Subject: Re: aio completions vs file_accessed race, was: Re: [PATCH 7/8] xfs: split direct I/O and DAX path Message-ID: <20160929203320.GE14092@birch.djwong.org> References: <1466609236-23801-1-git-send-email-hch@lst.de> <1466609236-23801-8-git-send-email-hch@lst.de> <20160929025351.GB4901@birch.djwong.org> <20160929083824.GA12799@lst.de> <20160929201834.GA5872@lst.de> <20160929201849.GB5872@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160929201849.GB5872@lst.de> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Sep 29, 2016 at 10:18:49PM +0200, Christoph Hellwig wrote: > On Thu, Sep 29, 2016 at 10:18:34PM +0200, Christoph Hellwig wrote: > > Can you try the patch below? That just moves the file_accessed call > > before the I/O, similar to how we handle timestamp updates on the write > > side. generic_file_read_iter will also need a similar update. > > And now with patch: > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 349f328..6919412 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -270,6 +270,8 @@ xfs_file_dio_aio_read( > return -EINVAL; > } > > + file_accessed(iocb->ki_filp); > + > /* > * Locking is a bit tricky here. If we take an exclusive lock for direct > * IO, we effectively serialise all new concurrent read IO to this file > @@ -324,7 +326,6 @@ xfs_file_dio_aio_read( > } > xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED); > > - file_accessed(iocb->ki_filp); > return ret; > } > I noticed that g/323 only breaks when the XFS is on a real disk; on pmem it works fine with or without the patch. That said, it makes the crash go away and the patch looks ok, so: Reviewed-by: Darrick J. Wong Tested-by: Darrick J. Wong --D