From: Andrei Borzenkov <arvidjaar@gmail.com>
To: kreijack@inwind.it, linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: BUG: BTRFS and O_DIRECT could lead to wrong checksum and wrong data
Date: Fri, 15 Sep 2017 06:55:54 +0300 [thread overview]
Message-ID: <3fc175a8-a61b-6060-5c78-abbbe2e61037@gmail.com> (raw)
In-Reply-To: <cf8a733f-2c9d-7ffe-e865-4c13d99dfb60@libero.it>
15.09.2017 01:00, Goffredo Baroncelli пишет:
>
> 2) The second bug, is a more severe bug. If during a writing of a buffer with O_DIRECT, the buffer is updated at the same time by a second process, the checksum may be incorrect.
>
Is it btrfs specific? If buffer is updated before it was actually
consumed by kernel, this likely means data corruption on any filesystem.
I.e. there should be clear indication from kernel that buffer can be
reused by application, in your example - when pwrite returns. So when
data corruption happens - during pwrite or after? If data is corrupted
during pwrite, it is arguably application fault - it should disallow
concurrent access.
next prev parent reply other threads:[~2017-09-15 3:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-14 22:00 BUG: BTRFS and O_DIRECT could lead to wrong checksum and wrong data Goffredo Baroncelli
2017-09-14 22:18 ` Hugo Mills
2017-09-15 6:04 ` Goffredo Baroncelli
2017-09-15 8:26 ` Hugo Mills
2017-09-15 9:50 ` Marat Khalili
2017-09-15 10:12 ` Paul Jones
2017-09-15 17:37 ` Goffredo Baroncelli
2017-09-15 17:14 ` Goffredo Baroncelli
2017-09-15 3:55 ` Andrei Borzenkov [this message]
2017-09-15 5:50 ` Goffredo Baroncelli
2017-09-15 17:01 ` Andrei Borzenkov
2017-09-15 17:30 ` Goffredo Baroncelli
2017-09-15 17:01 ` Liu Bo
2017-09-15 18:57 ` Goffredo Baroncelli
2017-09-15 19:14 ` Liu Bo
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