2010/3/26, Aneesh Kumar K. V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>:
> On Fri, 26 Mar 2010 21:44:33 +0800, jing zhang <zj.barak@xxxxxxxxx> wrote:
>> 2010/3/26, Aneesh Kumar K. V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>:
>> > On Thu, 25 Mar 2010 22:54:21 +0800, jing zhang <zj.barak@xxxxxxxxx>
>> > wrote:
>> >> From: Jing Zhang <zj.barak@xxxxxxxxx>
>> >>
>> >> Date: Wed Mar 25 22:55:04 2010
>> >>
>> >> Checking bug seems not at right place, and the function itself should
>> >> be inlined.
>> >>
>> >> Cc: Theodore Ts'o <tytso@xxxxxxx>
>> >> Cc: Andreas Dilger <adilger@xxxxxxx>
>> >> Cc: Dave Kleikamp <shaggy@xxxxxxxxxxxxxxxxxx>
>> >> Cc: "Aneesh Kumar K. V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>> >> Signed-off-by: Jing Zhang <zj.barak@xxxxxxxxx>
>> >>
>> >> ---
>> >>
>> >> --- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800
>> >> +++ ext4_mm_leak/mballoc-10.c 2010-03-25 22:44:00.000000000 +0800
>> >> @@ -2786,9 +2786,7 @@ out_err:
>> >> static void ext4_mb_normalize_group_request(struct
>> >> ext4_allocation_context *ac)
>> >> {
>> >> struct super_block *sb = ac->ac_sb;
>> >> - struct ext4_locality_group *lg = ac->ac_lg;
>> >>
>> >> - BUG_ON(lg == NULL);
>> >> if (EXT4_SB(sb)->s_stripe)
>> >> ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_stripe;
>> >> else
>> >
>> > That BUG_ON is to ensure that the allocation context is actually having
>> > a locality group which is needed for group allocation request.
>> >
>> > -aneesh
>> >
>>
>> Please check
>> 1, the 3 lines at the end of ext4_mb_group_or_file()
>> 2, the function name of this patch
>>
>
> What i wanted to mention was the BUG_ON is there to ensure that we don't
> call ext4_mb_normalize_group_request on non group enabled allocation
> context by programming mistake. Doing that would cause ac_g_ex.fe_len
> to change. So that BUG_ON is there to capture a programming error.
>
> -aneesh
>
Thank you, Aneesh, for good explanation in patience.
Again, good weekend.
Still in work?
- zj
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