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 <20121025164350.GL10679@twin.jikos.cz>
From: Rock Lee <zimilo@code-trick.com>
Date: Fri, 26 Oct 2012 07:36:58 +0800
Message-ID: <CAMRmmpJ9R2xPE-ppoyD+9N53eWH0CO1DB8HLCZPdtsb=SaMLeg@mail.gmail.com>
Subject: Re: [PATCH V2][BTRFS-PROGS] [BUG] Fix Bug to corrupt the img file
 Reply-To: dave@jikos.cz
To: Rock Lee <zimilo@code-trick.com>, linux-btrfs@vger.kernel.org
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Thanks for your review.

Sorry for the problem line wrapped, I will resend the patch.


Thanks
-Rock

2012/10/26 David Sterba <dave@jikos.cz>:
> On Fri, Oct 26, 2012 at 12:12:24AM +0800, Rock Lee wrote:
>> Fix Bug to corrupt the img file
>>
>> Reproduce steps:
>>   > dd if=/dev/zero of=btrfs-small.img bs=1M count=1
>>   > ls -lh btrfs-small.img
>>   -rw-rw-r--. 1 rock rock 1.0M Oct 24 09:51 btrfs-small.img
>>                                       ^^^
>>   > mkfs.btrfs btrfs-small.img
>>   -rw-rw-r--. 1 rock rock 2.0M Oct 24 09:53 btrfs-small.img
>>                                       ^^^
>>
>> Here you can see the original img file's size goes larger to 2Mb.
>
> Thanks, fixes this particular bug; although it crashes later at
>
>   mkfs.btrfs: volumes.c:796: btrfs_alloc_chunk: Assertion `!(ret)' failed
>
> but this is a separate issue and you've sent patches for that IIRC.
>
>> --- a/utils.c
>> +++ b/utils.c
>> @@ -557,6 +557,12 @@ int btrfs_prepare_device(int fd, char *file, int
>> zero_end, u64 *block_count_ret,
>>         }
>>         if (max_block_count)
>>                 block_count = min(block_count, max_block_count);
>> +
>> +       if (block_count < 2 * 1024 * 1024) {
>> +               fprintf(stderr, "size of %s is too small(less than
>> 2Mb)\n", file);
>
> line wrapped, please check your mailer (easy to fix but additional
> unnecessary work)
>
>> +               exit(1);
>> +       }
>> +
>
> Otherwise ack from me.
>
> david