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Date: Tue, 5 Aug 2014 14:32:14 -0700
From: Zach Brown <zab@zabbo.net>
To: Fabian Frederick <fabf@skynet.be>
Cc: linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 1/1] Btrfs: fix sparse warning
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> > > Hello Zach,
> > >
> > >     Here's an untested patch which
> >
> > Try testing it.  It's easy with virtualization and xfstests.
> >
> > You'll find that sending to a file fails because each individual file
> > write call that makes up a send starts at offset 0 -- at the start of
> > the file.
> >
> > Getting this right means getting the semantics around updating the send
> > descriptors f_pos right.  It requires having a bit of a think about send
> > semantics and f_pos update locking.
> 
> Thanks for those informations Zach,
> 
> I've tried btrfs test scripts related to ioctl in xfstests (tests/btrfs/025,
> 035, 052, 055)
> but was not able to trigger that problem. Do I have to create another script,
> use some generic one
> or maybe use big test/scratch devices ?

No idea, sorry.  Maybe your patch is fine and I'm a dummy.  Maybe you
didn't test the kernel you thought you were testing.  Maybe the test
doesn't test what you changed.  You'll have to do some investigating to
find out.

- z