linux-ext4 - Re: [PATCH 03/12] ext4: prevent a fs without journal from being resized

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Message-ID: <CAGBYx2aVuYu1tDe-_=YWL4xZRpx8b+m3JO4ujdfDbGau+y8Pew@mail.gmail.com>
Date:	Mon, 18 Jul 2011 11:28:10 +0800
From:	Yongqiang Yang <xiaoqiangnk@...il.com>
To:	Tao Ma <tm@....ma>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 03/12] ext4: prevent a fs without journal from being resized

On Mon, Jul 18, 2011 at 11:17 AM, Tao Ma <tm@....ma> wrote:
> On 07/18/2011 10:52 AM, Yongqiang Yang wrote:
>> This patch prevents a fs without journal from being resized, because
>> it is easy to detroy the fs.
> Why you want to do this?  You see any corruption?
> At least in our product system, no-journal mode is heavily used and we
> really don't want to disable this feature.
I did not see any corruption.  If there is no journal in a fs, then if
an error happens during online resizing, the filesystem will be
destroyed easily, I thought.  Just my thought:-)  It needs much more
feedbacks.

Thanks,
Yongqiang.
>
> Thanks
> Tao
>>
>> Signed-off-by: Yongqiang Yang <xiaoqiangnk@...il.com>
>> ---
>>  fs/ext4/resize.c |   10 ++++++++++
>>  1 files changed, 10 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
>> index 53d9795..33ab40d 100644
>> --- a/fs/ext4/resize.c
>> +++ b/fs/ext4/resize.c
>> @@ -33,6 +33,16 @@ int ext4_resize_begin(struct super_block *sb)
>>               return -EPERM;
>>       }
>>
>> +     /*
>> +      * We are not allowed to do online-resizing on a filesystem without
>> +      * journal, otherwise, it is easy to destroy the filesystem.
>> +      */
>> +     if (!EXT4_SB(sb)->s_journal) {
>> +             ext4_warning(sb, "There is no journal for the filesystem, "
>> +                          "so online resizing is not allowed\n");
>> +             return -EPERM;
>> +     }
>> +
>>       if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
>>               ret = -EBUSY;
>>
>
>



-- 
Best Wishes
Yongqiang Yang
--
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