linux-kernel - Re: [PATCH] xfs: add missing cmap->br_state = XFS_EXT

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Message-ID: <Yh2Jc5DeF9D7jp8r@B-P7TQMD6M-0146.local>
Date:   Tue, 1 Mar 2022 10:48:19 +0800
From:   Gao Xiang <hsiangkao@...ux.alibaba.com>
To:     "Darrick J. Wong" <djwong@...nel.org>,
        xfs <linux-xfs@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] xfs: add missing cmap->br_state = XFS_EXT_NORM update

On Fri, Feb 18, 2022 at 07:30:42PM +0800, Gao Xiang wrote:
> On Fri, Feb 18, 2022 at 01:55:37PM +0800, Gao Xiang wrote:
> > Hi Darrick,
> > 
> > On Thu, Feb 17, 2022 at 09:40:32PM -0800, Darrick J. Wong wrote:
> > > On Thu, Feb 17, 2022 at 05:55:42PM +0800, Gao Xiang wrote:
> > > > COW extents are already converted into written real extents after
> > > > xfs_reflink_convert_cow_locked(), therefore cmap->br_state should
> > > > reflect it.
> > > > 
> > > > Otherwise, there is another necessary unwritten convertion
> > > > triggered in xfs_dio_write_end_io() for direct I/O cases.
> > > > 
> > > > Signed-off-by: Gao Xiang <hsiangkao@...ux.alibaba.com>
> > > 
> > > I /think/ this looks ok.  Does it test ok too?  AFAICT nothing in the
> > > iomap/writeback machinery cares the incorrect state because we always
> > > set IOMAP_F_SHARED (which triggers COW) so I think this is simply a fix
> > > for directio, like you said?
> > 
> > Yeah, I think so, from the code logic buffered i/o seems no impacted...
> > And the unnecessary unwritten convertion under direct i/o takes
> > noticeable extra overhead in our workloads...
> > 
> > I checked my last night xfstests, it seems it stops unexpectedly (maybe
> > due to some environmental problem). I will rerun tests today and
> > feedback later.
> 
> On my test environment machine, with linux 5.17-rc4,
> both w/ and w/o the patch, it fails:
> 
> generic/594 generic/600 xfs/158 xfs/160
> 
> I think no issue with this patch.

ping.. it seems a simple fix for direct I/O..

Thanks,
Gao Xiang

> 
> Thanks,
> Gao Xiang