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

From: Dave Chinner <david@fromorbit.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>,
	Christoph Hellwig <hch@lst.de>,
	Goldwyn Rodrigues <rgoldwyn@suse.de>,
	linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org,
	fdmanana@gmail.com, dsterba@suse.cz, 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: Fri, 10 Jul 2020 08:59:36 +1000	[thread overview]
Message-ID: <20200709225936.GZ2005@dread.disaster.area> (raw)
In-Reply-To: <20200709171038.GE7625@magnolia>

On Thu, Jul 09, 2020 at 10:10:38AM -0700, Darrick J. Wong wrote:
> On Thu, Jul 09, 2020 at 06:05:19PM +0100, Matthew Wilcox wrote:
> > On Thu, Jul 09, 2020 at 09:09:26AM -0700, Darrick J. Wong wrote:
> > > On Thu, Jul 09, 2020 at 12:25:27PM +1000, Dave Chinner wrote:
> > > > -	 */
> > > > -	ret = invalidate_inode_pages2_range(mapping,
> > > > -			pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
> > > > -	if (ret)
> > > > -		dio_warn_stale_pagecache(iocb->ki_filp);
> > > > -	ret = 0;
> > > > +	if (iov_iter_rw(iter) == WRITE) {
> > > > +		/*
> > > > +		 * Try to invalidate cache pages for the range we're direct
> > > > +		 * writing.  If this invalidation fails, tough, the write will
> > > > +		 * still work, but racing two incompatible write paths is a
> > > > +		 * pretty crazy thing to do, so we don't support it 100%.
> > > > +		 */
> > > > +		ret = invalidate_inode_pages2_range(mapping,
> > > > +				pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
> > > > +		if (ret)
> > > > +			dio_warn_stale_pagecache(iocb->ki_filp);
> > > > +		ret = 0;
> > > >  
> > > > -	if (iov_iter_rw(iter) == WRITE && !wait_for_completion &&
> > > > -	    !inode->i_sb->s_dio_done_wq) {
> > > > -		ret = sb_init_dio_done_wq(inode->i_sb);
> > > > -		if (ret < 0)
> > > > -			goto out_free_dio;
> > > > +		if (!wait_for_completion &&
> > > > +		    !inode->i_sb->s_dio_done_wq) {
> > > > +			ret = sb_init_dio_done_wq(inode->i_sb);
> > > > +			if (ret < 0)
> > > > +				goto out_free_dio;
> 
> ...and yes I did add in the closing brace here. :P

Doh! I forgot to refresh the patch after fixing that. :/

Thanks!

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com