From: Avi Kivity <avi@redhat.com>
To: Nick Piggin <npiggin@suse.de>
Cc: Cesar Eduardo Barros <cesarb@cesarb.net>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] mm: Swap checksum
Date: Mon, 24 May 2010 13:51:43 +0300 [thread overview]
Message-ID: <4BFA5A3F.4040005@redhat.com> (raw)
In-Reply-To: <20100524073259.GW2516@laptop>
On 05/24/2010 10:32 AM, Nick Piggin wrote:
>
> I wonder, though. If we no longer trust block devices to give the
> correct data back, should we provide a meta block device to do error
> detection?
Some block devices do provide space for end-to-end checksums. For the
ones that don't, I see no efficient way of adding it (either we turn one
access into two, or we have a non-power-of-two block size).
> No production filesystem on Linux has checksums (well, ext4
> has a few). Of the ones that add checksumming, I'd say most will not do
> data checksumming (and for direct IO it is not done).
>
I believe btrfs checksums direct IO. Unfortunately it has some way to
go before it can be used in production.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: Nick Piggin <npiggin@suse.de>
Cc: Cesar Eduardo Barros <cesarb@cesarb.net>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] mm: Swap checksum
Date: Mon, 24 May 2010 13:51:43 +0300 [thread overview]
Message-ID: <4BFA5A3F.4040005@redhat.com> (raw)
In-Reply-To: <20100524073259.GW2516@laptop>
On 05/24/2010 10:32 AM, Nick Piggin wrote:
>
> I wonder, though. If we no longer trust block devices to give the
> correct data back, should we provide a meta block device to do error
> detection?
Some block devices do provide space for end-to-end checksums. For the
ones that don't, I see no efficient way of adding it (either we turn one
access into two, or we have a non-power-of-two block size).
> No production filesystem on Linux has checksums (well, ext4
> has a few). Of the ones that add checksumming, I'd say most will not do
> data checksumming (and for direct IO it is not done).
>
I believe btrfs checksums direct IO. Unfortunately it has some way to
go before it can be used in production.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
--
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next prev parent reply other threads:[~2010-05-24 10:51 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-22 18:08 [PATCH 0/3] mm: Swap checksum Cesar Eduardo Barros
2010-05-22 18:08 ` Cesar Eduardo Barros
2010-05-22 18:08 ` [PATCH 1/3] mm/swapfile.c: better messages for swap_info_get Cesar Eduardo Barros
2010-05-22 18:08 ` Cesar Eduardo Barros
2010-05-22 18:13 ` Borislav Petkov
2010-05-22 18:13 ` Borislav Petkov
2010-05-22 18:18 ` Cesar Eduardo Barros
2010-05-22 18:18 ` Cesar Eduardo Barros
2010-05-22 18:08 ` [PATCH 2/3] kernel/power/swap.c: do not use end_swap_bio_read Cesar Eduardo Barros
2010-05-22 18:08 ` Cesar Eduardo Barros
2010-05-22 18:08 ` [PATCH 3/3] mm: Swap checksum Cesar Eduardo Barros
2010-05-22 18:08 ` Cesar Eduardo Barros
2010-05-23 15:19 ` Avi Kivity
2010-05-23 15:19 ` Avi Kivity
2010-05-23 18:58 ` Cesar Eduardo Barros
2010-05-23 18:58 ` Cesar Eduardo Barros
2010-05-24 6:41 ` Avi Kivity
2010-05-24 6:41 ` Avi Kivity
2010-05-24 7:32 ` Nick Piggin
2010-05-24 7:32 ` Nick Piggin
2010-05-24 10:51 ` Avi Kivity [this message]
2010-05-24 10:51 ` Avi Kivity
2010-05-24 11:24 ` Cesar Eduardo Barros
2010-05-24 11:24 ` Cesar Eduardo Barros
2010-05-23 14:03 ` [PATCH 0/3] " Minchan Kim
2010-05-23 14:03 ` Minchan Kim
2010-05-23 18:32 ` Cesar Eduardo Barros
2010-05-23 18:32 ` Cesar Eduardo Barros
2010-05-24 0:09 ` Minchan Kim
2010-05-24 0:09 ` Minchan Kim
2010-05-24 0:57 ` Cesar Eduardo Barros
2010-05-24 0:57 ` Cesar Eduardo Barros
2010-05-24 2:05 ` Minchan Kim
2010-05-24 2:05 ` Minchan Kim
2010-05-24 10:50 ` Cesar Eduardo Barros
2010-05-24 10:50 ` Cesar Eduardo Barros
2010-05-25 23:52 ` Minchan Kim
2010-05-25 23:52 ` Minchan Kim
2010-05-26 10:21 ` Cesar Eduardo Barros
2010-05-26 10:21 ` Cesar Eduardo Barros
2010-05-26 15:31 ` Minchan Kim
2010-05-26 15:31 ` Minchan Kim
2010-05-26 21:28 ` Valdis.Kletnieks
2010-05-26 22:45 ` Minchan Kim
2010-05-26 22:45 ` Minchan Kim
2010-05-26 23:19 ` Cesar Eduardo Barros
2010-05-26 23:19 ` Cesar Eduardo Barros
2010-05-26 23:27 ` Minchan Kim
2010-05-26 23:27 ` Minchan Kim
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