2017-11-07 16:39:34

by Yunlong Song

Subject: Re: [PATCH v2] f2fs: add bug_on when f2fs_gc even fails to get one victim

Because I find that some out-of-free problem is caused by the failure
of get victim target. For example, chao has pointed out that he has
found out a bug when adding this bug_on last week.

On 2017/11/7 10:40, Jaegeuk Kim wrote:
> On 11/06, Jaegeuk Kim wrote:
>> On 11/06, Yunlong Song wrote:
>>> Agree.
>>>
>>> On 2017/11/3 11:44, Jaegeuk Kim wrote:
>>>> On 10/13, Yunlong Song wrote:
>>>>> This can help us to debug on some corner case.
>>>>>
>>>>> Signed-off-by: Yunlong Song <[email protected]>
>>>>> Signed-off-by: Chao Yu <[email protected]>
>>>>> ---
>>>>> fs/f2fs/gc.c | 6 +++++-
>>>>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>>>>> index 197ebf4..2b03202 100644
>>>>> --- a/fs/f2fs/gc.c
>>>>> +++ b/fs/f2fs/gc.c
>>>>> @@ -986,6 +986,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
>>>>> .ilist = LIST_HEAD_INIT(gc_list.ilist),
>>>>> .iroot = RADIX_TREE_INIT(GFP_NOFS),
>>>>> };
>>>>> + bool need_fggc = false;
>>>>> trace_f2fs_gc_begin(sbi->sb, sync, background,
>>>>> get_pages(sbi, F2FS_DIRTY_NODES),
>>>>> @@ -1018,8 +1019,10 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
>>>>> if (ret)
>>>>> goto stop;
>>>>> }
>>>>> - if (has_not_enough_free_secs(sbi, 0, 0))
>>>>> + if (has_not_enough_free_secs(sbi, 0, 0)) {
>>>>> gc_type = FG_GC;
>>>>> + need_fggc = true;
>>>>> + }
>>>>> }
>>>>> /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
>>>>> @@ -1028,6 +1031,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
>>>>> goto stop;
>>>>> }
>>>>> if (!__get_victim(sbi, &segno, gc_type)) {
>>>>> + f2fs_bug_on(sbi, !total_freed && need_fggc);
>>>> Just like this?
>>> That's OK.
>> I'm not quite sure whether this is really a bug_on case.
>> Let me make it WARN_ON() for debugging purpose first.
> BTW, why is this the special case where BG_GC detects FG_GC?
>
>> Thanks,
>>
>>>> f2fs_bug_on(sbi, !total_freed && !sync && gc_type == FG_GC);
>>>>
>>>>> ret = -ENODATA;
>>>>> goto stop;
>>>>> }
>>>>> --
>>>>> 1.8.5.2
>>>> .
>>>>
>>> --
>>> Thanks,
>>> Yunlong Song
>>>
> .
>

--
Thanks,
Yunlong Song



From 1583426060503316386@xxx Tue Nov 07 16:39:25 +0000 2017
X-GM-THRID: 1580969854381445046
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2017-11-07 16:39:25

by Jaegeuk Kim

Subject: Re: [PATCH v2] f2fs: add bug_on when f2fs_gc even fails to get one victim

On 11/07, Yunlong Song wrote:
> Because I find that some out-of-free problem is caused by the failure
> of get victim target. For example, chao has pointed out that he has
> found out a bug when adding this bug_on last week.

That's NOT what I asked. Why not checking FG_GC all the time like this?

f2fs_bug_on(sbi, !total_freed && gc_type == FG_GC);

>
> On 2017/11/7 10:40, Jaegeuk Kim wrote:
> > On 11/06, Jaegeuk Kim wrote:
> > > On 11/06, Yunlong Song wrote:
> > > > Agree.
> > > >
> > > > On 2017/11/3 11:44, Jaegeuk Kim wrote:
> > > > > On 10/13, Yunlong Song wrote:
> > > > > > This can help us to debug on some corner case.
> > > > > >
> > > > > > Signed-off-by: Yunlong Song <[email protected]>
> > > > > > Signed-off-by: Chao Yu <[email protected]>
> > > > > > ---
> > > > > > fs/f2fs/gc.c | 6 +++++-
> > > > > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > > > > > index 197ebf4..2b03202 100644
> > > > > > --- a/fs/f2fs/gc.c
> > > > > > +++ b/fs/f2fs/gc.c
> > > > > > @@ -986,6 +986,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
> > > > > > .ilist = LIST_HEAD_INIT(gc_list.ilist),
> > > > > > .iroot = RADIX_TREE_INIT(GFP_NOFS),
> > > > > > };
> > > > > > + bool need_fggc = false;
> > > > > > trace_f2fs_gc_begin(sbi->sb, sync, background,
> > > > > > get_pages(sbi, F2FS_DIRTY_NODES),
> > > > > > @@ -1018,8 +1019,10 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
> > > > > > if (ret)
> > > > > > goto stop;
> > > > > > }
> > > > > > - if (has_not_enough_free_secs(sbi, 0, 0))
> > > > > > + if (has_not_enough_free_secs(sbi, 0, 0)) {
> > > > > > gc_type = FG_GC;
> > > > > > + need_fggc = true;
> > > > > > + }
> > > > > > }
> > > > > > /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
> > > > > > @@ -1028,6 +1031,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
> > > > > > goto stop;
> > > > > > }
> > > > > > if (!__get_victim(sbi, &segno, gc_type)) {
> > > > > > + f2fs_bug_on(sbi, !total_freed && need_fggc);
> > > > > Just like this?
> > > > That's OK.
> > > I'm not quite sure whether this is really a bug_on case.
> > > Let me make it WARN_ON() for debugging purpose first.
> > BTW, why is this the special case where BG_GC detects FG_GC?
> >
> > > Thanks,
> > >
> > > > > f2fs_bug_on(sbi, !total_freed && !sync && gc_type == FG_GC);
> > > > >
> > > > > > ret = -ENODATA;
> > > > > > goto stop;
> > > > > > }
> > > > > > --
> > > > > > 1.8.5.2
> > > > > .
> > > > >
> > > > --
> > > > Thanks,
> > > > Yunlong Song
> > > >
> > .
> >
>
> --
> Thanks,
> Yunlong Song
>

From 1583422272466936677@xxx Tue Nov 07 15:39:13 +0000 2017
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