From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 2C7707F51 for ; Thu, 21 Aug 2014 08:08:57 -0500 (CDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay2.corp.sgi.com (Postfix) with ESMTP id F24DD304048 for ; Thu, 21 Aug 2014 06:08:53 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id eCRsWUL89heUrWLY (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Thu, 21 Aug 2014 06:08:53 -0700 (PDT) Date: Thu, 21 Aug 2014 09:08:47 -0400 From: Brian Foster Subject: Re: [PATCH 2/6] xfs: don't zero partial page cache pages during O_DIRECT writes Message-ID: <20140821130847.GC64112@bfoster.bfoster> References: <1408597754-13526-1-git-send-email-david@fromorbit.com> <1408597754-13526-3-git-send-email-david@fromorbit.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1408597754-13526-3-git-send-email-david@fromorbit.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: clm@fb.com, xfs@oss.sgi.com On Thu, Aug 21, 2014 at 03:09:10PM +1000, Dave Chinner wrote: > From: Chris Mason > > xfs is using truncate_pagecache_range to invalidate the page cache > during DIO reads. This is different from the other filesystems who > only invalidate pages during DIO writes. > > truncate_pagecache_range is meant to be used when we are freeing the > underlying data structs from disk, so it will zero any partial > ranges in the page. This means a DIO read can zero out part of the > page cache page, and it is possible the page will stay in cache. > > buffered reads will find an up to date page with zeros instead of > the data actually on disk. > > This patch fixes things by using invalidate_inode_pages2_range > instead. It preserves the page cache invalidation, but won't zero > any pages. > > [dchinner: catch error and warn if it fails. Comment.] > > cc: stable@vger.kernel.org > Signed-off-by: Chris Mason > Reviewed-by: Dave Chinner > Signed-off-by: Dave Chinner > --- Reviewed-by: Brian Foster > fs/xfs/xfs_file.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 076b170..827cfb2 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -296,7 +296,16 @@ xfs_file_read_iter( > xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL); > return ret; > } > - truncate_pagecache_range(VFS_I(ip), pos, -1); > + > + /* > + * Invalidate whole pages. This can return an error if > + * we fail to invalidate a page, but this should never > + * happen on XFS. Warn if it does fail. > + */ > + ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, > + pos >> PAGE_CACHE_SHIFT, -1); > + WARN_ON_ONCE(ret); > + ret = 0; > } > xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL); > } > -- > 2.0.0 > > _______________________________________________ > xfs mailing list > xfs@oss.sgi.com > http://oss.sgi.com/mailman/listinfo/xfs _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs