From: Matthew Bobrowski <mbobrowski@mbobrowski.org>
To: Dave Chinner <david@fromorbit.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
Christoph Hellwig <hch@lst.de>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Andreas Gruenbacher <agruenba@redhat.com>,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, Dave Chinner <dchinner@redhat.com>
Subject: Re: [PATCH 01/14] iomap: iomap that extends beyond EOF should be marked dirty
Date: Fri, 18 Oct 2019 10:08:14 +1100 [thread overview]
Message-ID: <20191017230814.GB31874@bobrowski> (raw)
In-Reply-To: <20191017215613.GN16973@dread.disaster.area>
On Fri, Oct 18, 2019 at 08:56:13AM +1100, Dave Chinner wrote:
> On Thu, Oct 17, 2019 at 11:39:17AM -0700, Darrick J. Wong wrote:
> > On Thu, Oct 17, 2019 at 07:56:11PM +0200, Christoph Hellwig wrote:
> > > From: Dave Chinner <dchinner@redhat.com>
> > >
> > > When doing a direct IO that spans the current EOF, and there are
> > > written blocks beyond EOF that extend beyond the current write, the
> > > only metadata update that needs to be done is a file size extension.
> > >
> > > However, we don't mark such iomaps as IOMAP_F_DIRTY to indicate that
> > > there is IO completion metadata updates required, and hence we may
> > > fail to correctly sync file size extensions made in IO completion
> > > when O_DSYNC writes are being used and the hardware supports FUA.
> > >
> > > Hence when setting IOMAP_F_DIRTY, we need to also take into account
> > > whether the iomap spans the current EOF. If it does, then we need to
> > > mark it dirty so that IO completion will call generic_write_sync()
> > > to flush the inode size update to stable storage correctly.
> > >
> > > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> > > Signed-off-by: Christoph Hellwig <hch@lst.de>
> >
> > Looks ok, but need fixes tag. Also, might it be wise to split off the
> > ext4 section into a separate patch so that it can be backported
> > separately?
>
> I 've done a bit more digging on this, and the ext4 part is not
> needed for DAX as IOMAP_F_DIRTY is only used in the page fault path
> and hence can't change the file size. As such, this only affects
> direct IO. Hence the ext4 hunk can be added to the ext4 iomap-dio
> patchset that is being developed rather than being in this patch.
Noted, thanks Dave. I've incorporated the ext4 related change into my patch
series.
--<M>--
next prev parent reply other threads:[~2019-10-17 23:08 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-17 17:56 lift the xfs writepage code into iomap v8 Christoph Hellwig
2019-10-17 17:56 ` [PATCH 01/14] iomap: iomap that extends beyond EOF should be marked dirty Christoph Hellwig
2019-10-17 18:39 ` Darrick J. Wong
2019-10-17 21:56 ` Dave Chinner
2019-10-17 23:08 ` Matthew Bobrowski [this message]
2019-10-18 1:02 ` Darrick J. Wong
2019-10-18 7:20 ` Christoph Hellwig
2019-10-17 17:56 ` [PATCH 02/14] xfs: initialize iomap->flags in xfs_bmbt_to_iomap Christoph Hellwig
2019-10-17 17:56 ` [PATCH 03/14] xfs: set IOMAP_F_NEW more carefully Christoph Hellwig
2019-10-17 17:56 ` [PATCH 04/14] xfs: use a struct iomap in xfs_writepage_ctx Christoph Hellwig
2019-10-17 17:56 ` [PATCH 05/14] xfs: refactor the ioend merging code Christoph Hellwig
2019-10-17 18:40 ` Darrick J. Wong
2019-10-17 17:56 ` [PATCH 06/14] xfs: turn io_append_trans into an io_private void pointer Christoph Hellwig
2019-10-17 17:56 ` [PATCH 07/14] xfs: remove the fork fields in the writepage_ctx and ioend Christoph Hellwig
2019-10-17 17:56 ` [PATCH 08/14] iomap: zero newly allocated mapped blocks Christoph Hellwig
2019-10-17 17:56 ` [PATCH 09/14] iomap: lift common tracing code from xfs to iomap Christoph Hellwig
2019-10-17 17:56 ` [PATCH 10/14] iomap: lift the xfs writeback code " Christoph Hellwig
2019-10-17 18:48 ` Darrick J. Wong
2019-10-17 22:01 ` Dave Chinner
2019-10-17 17:56 ` [PATCH 11/14] iomap: warn on inline maps in iomap_writepage_map Christoph Hellwig
2019-10-17 17:56 ` [PATCH 12/14] iomap: move struct iomap_page out of iomap.h Christoph Hellwig
2019-10-17 17:56 ` [PATCH 13/14] iomap: cleanup iomap_ioend_compare Christoph Hellwig
2019-10-17 17:56 ` [PATCH 14/14] iomap: pass a struct page to iomap_finish_page_writeback Christoph Hellwig
2019-10-17 18:41 ` Darrick J. Wong
2019-10-17 20:49 ` lift the xfs writepage code into iomap v8 Darrick J. Wong
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