linux-ext4 - Re: [RFC PATCH 10/17] signed int -> blk64_t to fix bugs at 2^31

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Date:	Thu, 13 Nov 2008 22:04:58 -0600
From:	Eric Sandeen <sandeen@...hat.com>
To:	Valerie Aurora Henson <vaurora@...hat.com>
CC:	Andreas Dilger <adilger@....com>, "Theodore Ts'o" <tytso@....edu>,
	linux-ext4@...r.kernel.org
Subject: Re: [RFC PATCH 10/17] signed int -> blk64_t to fix bugs at 2^31 -
 2^32 blocks

Valerie Aurora Henson wrote:
> On Thu, Nov 13, 2008 at 09:42:52PM -0600, Eric Sandeen wrote:
>> Valerie Aurora Henson wrote:
>>> On Thu, Nov 13, 2008 at 12:57:42PM -0700, Andreas Dilger wrote:
>>>> On Nov 11, 2008  19:43 -0800, Valerie Aurora Henson wrote:
>>>>> diff --git a/lib/ext2fs/alloc_tables.c b/lib/ext2fs/alloc_tables.c
>>>>> index 7235f7d..71ad445 100644
>>>>> --- a/lib/ext2fs/alloc_tables.c
>>>>> +++ b/lib/ext2fs/alloc_tables.c
>>>>> @@ -147,7 +147,7 @@ errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
>>>>> -		int prev_block = 0;
>>>>> +		blk64_t prev_block = 0;
>>>>> @@ -178,7 +178,7 @@ errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
>>>>>  	if (flexbg_size) {
>>>>> -		int prev_block = 0;
>>>>> +		blk64_t prev_block = 0;
>>>> These appear to be defects in the base code and should be landed ASAP
>>>> (as int -> blk_t) independently of this patch series.
>>> Agreed.  Ted, is this a good format for you or do you want me to
>>> regenerate against something?
>> Is it?
>>
>>         if (flexbg_size) {
>>                 int prev_block = 0;
>>                 if (group && fs->group_desc[group-1].bg_block_bitmap)
>>                         prev_block =
>> fs->group_desc[group-1].bg_block_bitmap;
>>                 start_blk = flexbg_offset(fs, group, prev_block, bmap,
>>                                                  0, rem_grps, 1);
>>                 last_blk = ext2fs_group_last_block(fs, last_grp);
>>         }
>>
>> bg_block_bitmap is only a __u32, and that's what we assign to prev_block.
> 
> It's a signed/unsigned bug (int vs. blk_t) - it shows up at > 2^31
> blocks.

oh, sigh, I was thinking of blk_t as a 64 bit here already :)

-Eric
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