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

[Chao Yu <chao@kernel.org>]

On 2017/10/13 19:20, Yunlong Song wrote:
> Yep, both are OK, since I do not care it is foreground or background. Here it just needs to do gc.

But you only set need_gc as true for foreground GC case.

Thanks,

> 
> On 2017/10/13 19:09, Chao Yu wrote:
>> On 2017/10/11 21:51, Yunlong Song wrote:
>>> This can help us to debug on some corner case.
>>>
>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>>> ---
>>>   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..960503e 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_gc = false;
>> How about changing variable name to need_fggc for better readability?
>>
>> Thanks,
>>
>>>         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_gc = 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_gc);
>>>           ret = -ENODATA;
>>>           goto stop;
>>>       }
>>>
>> .
>>
>