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Date: Tue, 20 Jun 2017 05:43:55 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>, linux-fsdevel@vger.kernel.org,
	linux-block@vger.kernel.org, adilger@dilger.ca,
	martin.petersen@oracle.com
Subject: Re: [PATCH 04/11] fs: add support for allowing applications to pass
 in write life time hints
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On Tue, Jun 20, 2017 at 06:43:10AM -0600, Jens Axboe wrote:
> > Question:  IFF we can get the per-file hints to propagate to the
> > writeback code (which I think is pretty easy for ext4/xfs/bdev, not
> > sure about btrfs) do we even need the per-inode ones at all?
> 
> How is that possible, the file could be long gone by the time
> the writeback kicks in?

each time a page/buffer is dirtied we can propagate the hint.