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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Dave Jones <davej@codemonkey.org.uk>, Chris Mason <clm@fb.com>,
	Josef Bacik <jbacik@fb.com>, David Sterba <dsterba@suse.com>,
	linux-btrfs@vger.kernel.org,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: btrfs_direct_IO oops
Date: Sat, 8 Oct 2016 19:29:03 +0100	[thread overview]
Message-ID: <20161008182903.GU19539@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20161008180806.fmpwtw4vcc7lzd36@codemonkey.org.uk>

On Sat, Oct 08, 2016 at 02:08:06PM -0400, Dave Jones wrote:
> That code: matches this dissembly:
> 
>                 for (i = seg + 1; i < iter->nr_segs; i++) {

*whoa*

OK, that loop in check_direct_IO() should be done *ONLY* for
iovec iter - even for a bvec one it's completely bogus, and
for pipe ones it blows up immediately.

Sorry, I'd missed that bogosity - replace
        if (iov_iter_rw(iter) == WRITE)
		return 0;
with
	if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
		return 0;
in there; that should fix the damn thing.

  reply	other threads:[~2016-10-08 18:30 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-08 18:08 btrfs_direct_IO oops Dave Jones
2016-10-08 18:29 ` Al Viro [this message]
2016-10-08 23:20   ` Dave Jones
2016-10-09 15:11     ` Dave Jones
2016-10-10  3:43       ` Al Viro
2016-10-10 13:11         ` Dave Jones
2016-10-10 15:55           ` Al Viro
2016-10-10 17:17             ` Dave Jones

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