linux-kernel - Re: [PATCH] dio: invalidate clean pages before dio write

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Date:	Fri, 9 Mar 2007 20:22:44 -0500
From:	Benjamin LaHaise <bcrl@...ck.org>
To:	Zach Brown <zach.brown@...cle.com>
Cc:	linux-aio@...ck.org, linux-kernel@...r.kernel.org,
	Jeff Moyer <jmoyer@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] dio: invalidate clean pages before dio write

On Fri, Mar 09, 2007 at 02:35:57PM -0800, Zach Brown wrote:
> +	if (rw == WRITE && mapping->nrpages) {
> +		int err = invalidate_inode_pages2_range(mapping,
> +					      offset >> PAGE_CACHE_SHIFT, end);
> +		if (err && retval >= 0)
> +			retval = err;
> +	}

I don't think reporting the error is the correct thing to do in the presense 
of the write having completed.  It's a race that the caller can do nothing 
about and is arguably a kernel bug, so I'd rather do something like:

		if (err) {
			if (!retval)
				retval = err;
			else
				printk_ratelimited(KERN_DEBUG
					"dio sucks and hit the race %ld %ld\n",
					retval, err);
		}

Aside from that, I much prefer this approach to fix the problem than going 
around and changing semantics.  Feel free to add my Signed-off-by.

		-ben
-- 
"Time is of no importance, Mr. President, only life is important."
Don't Email: <zyntrop@...ck.org>.
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