Re: [PATCH] fs/ext4/super.c: Let 'counters' switched by SMP

From: Chen Gang
Date: Tue Jul 15 2014 - 06:07:03 EST

On 07/15/2014 05:31 PM, Theodore Ts'o wrote:
> On Tue, Jul 15, 2014 at 09:05:29AM +0800, Chen Gang wrote:
>> When SMP is disabled, 'struct percpu_counter' has no 'counters' member,
>> so need skip it when in !SMP.
>> The related git commit:
>> "feab139 ext4: rearrange initialization to fix EXT4FS_DEBUG".
>> The related error (with allmodconfig under score):
>> CC [M] fs/ext4/super.o
>> fs/ext4/super.c: In function 'ext4_commit_super':
>> fs/ext4/super.c:4546:41: error: 'struct percpu_counter' has no member named 'counters'
>> if (EXT4_SB(sb)->s_freeclusters_counter.counters)
>> ^
>> fs/ext4/super.c:4550:39: error: 'struct percpu_counter' has no member named 'counters'
>> if (EXT4_SB(sb)->s_freeinodes_counter.counters)
> Thanks for the pointing out the problem. I though think the right way
> of fixing this problem, though, instead of using the #ifdef
> CONFIG_SMP, is to do this:
> if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeclusters_counter))
> ...

That sounds fine to me (unlike my ugly fix, your fix is common and
standard), thanks.

> I'll respin the "ext4: rearrange initialization to fix EXT4FS_DEBUG"
> commit to include this fix and give you credit in the commit logs for
> pointing out this issue.

Thank you for your work.

Chen Gang

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