From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org,
fdmanana@gmail.com, dsterba@suse.cz, david@fromorbit.com,
darrick.wong@oracle.com, cluster-devel@redhat.com,
linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org
Subject: Re: always fall back to buffered I/O after invalidation failures, was: Re: [PATCH 2/6] iomap: IOMAP_DIO_RWF_NO_STALE_PAGECACHE return if page invalidation fails
Date: Tue, 7 Jul 2020 07:43:46 -0500 [thread overview]
Message-ID: <20200707124346.xnr5gtcysuzehejq@fiona> (raw)
In-Reply-To: <20200701075310.GB29884@lst.de>
On 9:53 01/07, Christoph Hellwig wrote:
> On Mon, Jun 29, 2020 at 02:23:49PM -0500, Goldwyn Rodrigues wrote:
> > From: Goldwyn Rodrigues <rgoldwyn@suse.com>
> >
> > For direct I/O, add the flag IOMAP_DIO_RWF_NO_STALE_PAGECACHE to indicate
> > that if the page invalidation fails, return back control to the
> > filesystem so it may fallback to buffered mode.
> >
> > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
>
> I'd like to start a discussion of this shouldn't really be the
> default behavior. If we have page cache that can't be invalidated it
> actually makes a whole lot of sense to not do direct I/O, avoid the
> warnings, etc.
>
> Adding all the relevant lists.
Since no one responded so far, let me see if I can stir the cauldron :)
What error should be returned in case of such an error? I think the
userspace process must be immediately informed if it in unable to
invalidate the page cache and complete the direct I/O. Currently, the
iomap code treats this as a writeback error and continues with the
direct I/O and the userspace process comes to know only during file
closure.
If such a change is incorporated, are the current userspace applications
prepared for it?
--
Goldwyn
WARNING: multiple messages have this Message-ID (diff)
From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] always fall back to buffered I/O after invalidation failures, was: Re: [PATCH 2/6] iomap: IOMAP_DIO_RWF_NO_STALE_PAGECACHE return if page invalidation fails
Date: Tue, 7 Jul 2020 07:43:46 -0500 [thread overview]
Message-ID: <20200707124346.xnr5gtcysuzehejq@fiona> (raw)
In-Reply-To: <20200701075310.GB29884@lst.de>
On 9:53 01/07, Christoph Hellwig wrote:
> On Mon, Jun 29, 2020 at 02:23:49PM -0500, Goldwyn Rodrigues wrote:
> > From: Goldwyn Rodrigues <rgoldwyn@suse.com>
> >
> > For direct I/O, add the flag IOMAP_DIO_RWF_NO_STALE_PAGECACHE to indicate
> > that if the page invalidation fails, return back control to the
> > filesystem so it may fallback to buffered mode.
> >
> > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
>
> I'd like to start a discussion of this shouldn't really be the
> default behavior. If we have page cache that can't be invalidated it
> actually makes a whole lot of sense to not do direct I/O, avoid the
> warnings, etc.
>
> Adding all the relevant lists.
Since no one responded so far, let me see if I can stir the cauldron :)
What error should be returned in case of such an error? I think the
userspace process must be immediately informed if it in unable to
invalidate the page cache and complete the direct I/O. Currently, the
iomap code treats this as a writeback error and continues with the
direct I/O and the userspace process comes to know only during file
closure.
If such a change is incorporated, are the current userspace applications
prepared for it?
--
Goldwyn
next prev parent reply other threads:[~2020-07-07 12:43 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 19:23 [PATCH 0/6 v10] btrfs direct-io using iomap Goldwyn Rodrigues
2020-06-29 19:23 ` [PATCH 1/6] iomap: Convert wait_for_completion to flags Goldwyn Rodrigues
2020-06-29 23:03 ` David Sterba
2020-06-30 16:35 ` David Sterba
2020-07-01 7:34 ` Johannes Thumshirn
2020-07-01 7:50 ` Christoph Hellwig
2020-06-29 19:23 ` [PATCH 2/6] iomap: IOMAP_DIO_RWF_NO_STALE_PAGECACHE return if page invalidation fails Goldwyn Rodrigues
2020-07-01 7:53 ` always fall back to buffered I/O after invalidation failures, was: " Christoph Hellwig
2020-07-01 7:53 ` [Cluster-devel] " Christoph Hellwig
2020-07-07 12:43 ` Goldwyn Rodrigues [this message]
2020-07-07 12:43 ` Goldwyn Rodrigues
2020-07-07 12:57 ` Matthew Wilcox
2020-07-07 12:57 ` [Cluster-devel] " Matthew Wilcox
2020-07-07 13:00 ` Christoph Hellwig
2020-07-07 13:00 ` [Cluster-devel] " Christoph Hellwig
2020-07-08 6:51 ` Dave Chinner
2020-07-08 6:51 ` [Cluster-devel] " Dave Chinner
2020-07-08 13:54 ` Matthew Wilcox
2020-07-08 13:54 ` [Cluster-devel] " Matthew Wilcox
2020-07-08 16:54 ` Christoph Hellwig
2020-07-08 16:54 ` [Cluster-devel] " Christoph Hellwig
2020-07-08 17:11 ` Matthew Wilcox
2020-07-08 17:11 ` [Cluster-devel] " Matthew Wilcox
2020-07-09 8:26 ` Steven Whitehouse
2020-07-09 8:26 ` Steven Whitehouse
2020-07-09 2:25 ` Dave Chinner
2020-07-09 2:25 ` [Cluster-devel] " Dave Chinner
2020-07-09 16:09 ` Darrick J. Wong
2020-07-09 16:09 ` [Cluster-devel] " Darrick J. Wong
2020-07-09 17:05 ` Matthew Wilcox
2020-07-09 17:05 ` [Cluster-devel] " Matthew Wilcox
2020-07-09 17:10 ` Darrick J. Wong
2020-07-09 17:10 ` [Cluster-devel] " Darrick J. Wong
2020-07-09 22:59 ` Dave Chinner
2020-07-09 22:59 ` [Cluster-devel] " Dave Chinner
2020-07-10 16:03 ` Christoph Hellwig
2020-07-10 16:03 ` [Cluster-devel] " Christoph Hellwig
2020-07-12 11:36 ` Avi Kivity
2020-07-12 11:36 ` [Cluster-devel] " Avi Kivity
2020-07-07 13:49 ` Goldwyn Rodrigues
2020-07-07 13:49 ` [Cluster-devel] " Goldwyn Rodrigues
2020-07-07 14:01 ` Darrick J. Wong
2020-07-07 14:01 ` [Cluster-devel] " Darrick J. Wong
2020-07-07 14:30 ` Goldwyn Rodrigues
2020-07-07 14:30 ` [Cluster-devel] " Goldwyn Rodrigues
2020-06-29 19:23 ` [PATCH 3/6] btrfs: switch to iomap_dio_rw() for dio Goldwyn Rodrigues
2020-06-29 19:23 ` [PATCH 4/6] fs: remove dio_end_io() Goldwyn Rodrigues
2020-06-29 19:23 ` [PATCH 5/6] btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK Goldwyn Rodrigues
2020-06-29 19:23 ` [PATCH 6/6] btrfs: split btrfs_direct_IO to read and write part Goldwyn Rodrigues
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