Messages in this thread | | | Date | Thu, 21 Feb 2019 18:40:58 -0800 | From | Jaegeuk Kim <> | Subject | Re: [f2fs-dev] [PATCH] f2fs: don't clear CP_QUOTA_NEED_FSCK_FLAG |
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On 02/20, Chao Yu wrote: > On 2019/2/20 15:25, Chao Yu wrote: > > On 2019/2/20 15:08, Jaegeuk Kim wrote: > >> On 02/18, Chao Yu wrote: > >>> On 2019/2/16 12:55, Jaegeuk Kim wrote: > >>>> On 02/13, Chao Yu wrote: > >>>>> On 2019/2/12 10:33, Jaegeuk Kim wrote: > >>>>>> If we met this once, let fsck.f2fs clear this only. > >>>>>> Note that, this addresses all the subtle fault injection test. > >>>>>> > >>>>>> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > >>>>>> --- > >>>>>> fs/f2fs/checkpoint.c | 2 -- > >>>>>> 1 file changed, 2 deletions(-) > >>>>>> > >>>>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > >>>>>> index 03fea4efd64b..10a3ada28715 100644 > >>>>>> --- a/fs/f2fs/checkpoint.c > >>>>>> +++ b/fs/f2fs/checkpoint.c > >>>>>> @@ -1267,8 +1267,6 @@ static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc) > >>>>>> > >>>>>> if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH)) > >>>>>> __set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); > >>>>>> - else > >>>>>> - __clear_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); > >>>>> > >>>>> I didn't get it, previously, if we didn't persist all quota file's data in > >>>>> checkpoint, then we will tag CP_QUOTA_NEED_FSCK_FLAG in CP area, but in current > >>>>> checkpoint, we have persisted all quota file's data, quota files are consistent > >>>>> with all other files in filesystem, why we can't remove this NEED_FSCK flag..? > >>>> > >>>> I said it's subtle. So, I guessed 1) set CP_QUOTA_NEED_FSCK_FLAG, 2) clear > >>> > >>> I know it's subtle... and I agreed we can fix it like this in upstream > >>> first, but in our product, it's not rare that we hit the > >>> QUOTA_SKIP_FLUSH(its value is 4) case, later we may encounter long latency > >>> caused by quota repairing of fsck. > >>> > >>>> SBI_QUOTA_SKIP_FLUSH by checkpoint, 3) clear CP_QUOTA_NEED_FSCK_FLAG by another > >>>> checkpoint? > >>> > >>> But later if QUOTA_NEED_REPAIR is set, we will set QUOTA_NEED_FSCK_FLAG > >>> again, right? > >>> > >>> if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR)) > >>> __set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); > >>> > >>> > >>> So in order to figure out whether this is caused by out-of-order execution > >>> of below assignments: > >>> > >>> if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH)) > >>> __set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); > >>> else > >>> __clear_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); --- clear flag later > >>> > >>> if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR)) > >>> __set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); --- set flag first > >>> > >>> > >>> Could you have a try: > >>> > >>> if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR) || > >>> is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH)) > >>> __set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); > >>> else > >>> __clear_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); > >> > >> What does this mean? I'm in doubt we have a missing case where we clear this > > > > Cpu pipeline / compiler can make code out-of-order execution, which means: > > > > a = 1; > > b = 2; > > > > may actually be executed as the order of: > > > > b = 2; > > a = 1; > > > > So I doubt that below two line codes can be executed out-of-order: > > > > else > > __clear_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); --- clear flag later > > > > if () > > __set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); --- set flag first
In spin_lock_irqsave()?
> > > >> flag, CP_QUOTA_NEED_FSCK_FLAG. > > > > Agreed, I've checked each operation in f2fs_quota_operations yesterday, and > > didn't find any missing places yet... > > Oh, I mean the place where set SBI_QUOTA_NEED_REPAIR, I also doubt we > missed to set the flag.
So, I may need to keep this patch untill we find the missing case. I'll keep an eye on this.
> > Thanks, > > > > > Thanks, > > > >> > >>> > >>> Thanks, > >>> > >>>> > >>>>> > >>>>> Thanks, > >>>>> > >>>>>> > >>>>>> if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR)) > >>>>>> __set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); > >>>>>> > >>>> > >>>> . > >>>> > >> > >> . > >> > > > > > > > > _______________________________________________ > > Linux-f2fs-devel mailing list > > Linux-f2fs-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > > > > . > >
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