linux-kernel - Re: [PATCH] vfs: allow FILE_EXTENT_SAME (dedupe_file

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Message-ID: <20160718195147.GD17171@wotan.suse.de>
Date:	Mon, 18 Jul 2016 12:51:47 -0700
From:	Mark Fasheh <mfasheh@...e.de>
To:	Adam Borowski <kilobyte@...band.pl>
Cc:	Alexander Viro <viro@...iv.linux.org.uk>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-btrfs@...r.kernel.org,
	"Darrick J . Wong" <darrick.wong@...cle.com>
Subject: Re: [PATCH] vfs: allow FILE_EXTENT_SAME (dedupe_file_range) on a
 file opened ro

On Mon, Jul 18, 2016 at 12:13:38AM +0200, Adam Borowski wrote:
> Instead of checking the mode of the file descriptor, let's check whether it
> could have been opened rw.  This allows fixing intermittent exec failures
> when deduping a live system: anyone trying to exec a file currently being
> deduped gets ETXTBSY.
> 
> Issuing this ioctl on a ro file was already allowed for root/cap.
> 
> Tested on btrfs and not-yet-merged xfs, as only them implement this ioctl.
> 
> Signed-off-by: Adam Borowski <kilobyte@...band.pl>

Reviewed-by: Mark Fasheh <mfasheh@...e.de>
	--Mark

--
Mark Fasheh