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From: NeilBrown <neilb@suse.de>
To: Song Liu <songliubraving@fb.com>
Cc: Coly Li <colyli@suse.de>, NeilBrown <neilb@suse.com>,
	"linux-block\@vger.kernel.org" <linux-block@vger.kernel.org>,
	linux-raid <linux-raid@vger.kernel.org>
Subject: Re: [PATCH] md/raid0: avoid RAID0 data corruption due to layout confusion.
Date: Tue, 10 Sep 2019 09:33:46 +1000	[thread overview]
Message-ID: <87ftl5avtx.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <242E3FBD-C969-44E1-8DC7-BFE9E7CBE7FD@fb.com>

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On Mon, Sep 09 2019, Song Liu wrote:

> Hi Neil,
>
>> On Sep 9, 2019, at 7:57 AM, NeilBrown <neilb@suse.de> wrote:
>> 
>> 
>> If the drives in a RAID0 are not all the same size, the array is
>> divided into zones.
>> The first zone covers all drives, to the size of the smallest.
>> The second zone covers all drives larger than the smallest, up to
>> the size of the second smallest - etc.
>> 
>> A change in Linux 3.14 unintentionally changed the layout for the
>> second and subsequent zones.  All the correct data is still stored, but
>> each chunk may be assigned to a different device than in pre-3.14 kernels.
>> This can lead to data corruption.
>> 
>> It is not possible to determine what layout to use - it depends which
>> kernel the data was written by.
>> So we add a module parameter to allow the old (0) or new (1) layout to be
>> specified, and refused to assemble an affected array if that parameter is
>> not set.
>> 
>> Fixes: 20d0189b1012 ("block: Introduce new bio_split()")
>> cc: stable@vger.kernel.org (3.14+)
>> Signed-off-by: NeilBrown <neilb@suse.de>
>
> Thanks for the patches. They look great. However, I am having problem
> apply them (not sure whether it is a problem on my side). Could you 
> please push it somewhere so I can use cherry-pick instead?

I rebased them on block/for-next, fixed the problems that Guoqing found,
and pushed them to 
  https://github.com/neilbrown/linux md/raid0

NeilBrown

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  reply	other threads:[~2019-09-09 23:33 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-22 10:38 [RFC] How to handle an ugly md raid0 sector map bug ? Coly Li
2019-08-23  0:02 ` NeilBrown
2019-08-23 16:37   ` Song Liu
2019-08-23 17:03     ` Coly Li
2019-08-23 17:17       ` Song Liu
2019-08-23 17:47         ` Coly Li
2019-09-09  6:57           ` [PATCH] md/raid0: avoid RAID0 data corruption due to layout confusion NeilBrown
2019-09-09  6:58             ` [PATCH 2/2] md: add feature flag MD_FEATURE_RAID0_LAYOUT NeilBrown
2019-09-09 15:33               ` Guoqing Jiang
2019-09-09 23:26                 ` NeilBrown
2019-09-09 14:56             ` [PATCH] md/raid0: avoid RAID0 data corruption due to layout confusion Song Liu
2019-09-09 23:33               ` NeilBrown [this message]
2019-09-10 15:45                 ` Song Liu
2019-09-10 16:01                   ` Guoqing Jiang
2019-09-10 23:08                     ` NeilBrown
2019-09-11  9:56                       ` Song Liu
2019-09-11 22:48                         ` NeilBrown
2019-09-09 15:09             ` Guoqing Jiang
2019-09-09 23:34               ` NeilBrown

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