From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tao Ma Subject: Re: [PATCH 1/2] ext4: let mpage_submit_io works well when blocksize < pagesize Date: Sat, 26 Nov 2011 23:08:24 +0800 Message-ID: <4ED100E8.109@tao.ma> References: <1322039726-3587-1-git-send-email-xiaoqiangnk@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, achender@linux.vnet.ibm.com, tytso@mit.edu To: Yongqiang Yang Return-path: Received: from oproxy3-pub.bluehost.com ([69.89.21.8]:34402 "HELO oproxy3-pub.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752621Ab1KZPIf (ORCPT ); Sat, 26 Nov 2011 10:08:35 -0500 In-Reply-To: <1322039726-3587-1-git-send-email-xiaoqiangnk@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi Yongqiang, On 11/23/2011 05:15 PM, Yongqiang Yang wrote: > If there is a unwritten but clean buffer in a page and there is a dirty buffer > after the buffer, then mpage_submit_io does not write the dirty buffer out. > As a result, da_writepages loops forever. Did you ever meet with this bug or just find it to be a possible bug by skimming the code? Actually, I can't find a proper way to get a buffer which can satisfy the check. Thanks Tao > > This patch fixes the problem by checking dirty flag. > > Signed-off-by: Yongqiang Yang > --- > fs/ext4/inode.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 755f6c7..20a1d17 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -1339,8 +1339,11 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd, > clear_buffer_unwritten(bh); > } > > - /* skip page if block allocation undone */ > - if (buffer_delay(bh) || buffer_unwritten(bh)) > + /* > + * skip page if block allocation undone and > + * block is dirty > + */ > + if (ext4_bh_delay_or_unwritten(NULL, bh)) > skip_page = 1; > bh = bh->b_this_page; > block_start += bh->b_size;