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Subject: Re: [PATCH] ext4: Don't set dioread_nolock by default for blocksize <
 pagesize
To:     stable@vger.kernel.org
Cc:     "Theodore Y. Ts'o" <tytso@mit.edu>, linux-ext4@vger.kernel.org,
        Jan Kara <jack@suse.cz>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        Sasha Levin <sashal@kernel.org>
References: <87pndagw7s.fsf@linux.ibm.com>
 <20200327200744.12473-1-riteshh@linux.ibm.com>
 <20200329021728.GI53396@mit.edu>
From:   Ritesh Harjani <ritesh.list@gmail.com>
Message-ID: <e61fe76d-687f-3e34-6091-c501071b8a9a@gmail.com>
Date:   Mon, 11 May 2020 13:37:59 +0530
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Hello stable-list,

I think this subjected patch [1] missed the below fixes tag.
I guess the subjected patch is only picked for 5.7. And
AFAIU, this patch will be needed for 5.6 as well.

Could you please do the needful.

Fixes: 244adf6426ee31a (ext4: make dioread_nolock the default)

[1]: 
https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit/?h=dev&id=626b035b816b61a7a7b4d2205a6807e2f11a18c1


-ritesh

On 3/29/20 7:47 AM, Theodore Y. Ts'o wrote:
> On Sat, Mar 28, 2020 at 01:37:44AM +0530, Ritesh Harjani wrote:
>> Currently on calling echo 3 > drop_caches on host machine, we see
>> FS corruption in the guest. This happens on Power machine where
>> blocksize < pagesize.
>>
>> So as a temporary workaound don't enable dioread_nolock by default
>> for blocksize < pagesize until we identify the root cause.
>>
>> Also emit a warning msg in case if this mount option is manually
>> enabled for blocksize < pagesize.
>>
>> Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
> 
> Thanks, applied.
> 
> 					- Ted
>