2017-10-13 01:10:47

by Yunlong Song

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

Hi, Jay,
I think it should not happen when need_gc == true but total_freed
==0, so I add it as bug_on to let it panic at once. And even CHECK_FS is
closed, this can also printk WARNING message for notice.

On 2017/10/13 7:23, Jaegeuk Kim wrote:
> Hi Yunlong,
>
> On 10/11, Yunlong Song wrote:
>> This can help us to debug on some corner case.
>>
>> Signed-off-by: Yunlong Song <[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..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;
>>
>> 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);
> How about this, if this is for debugging purpose?
>
> if (!total_freed && need_gc)
> f2fs_msg(...);
>
> It's not a good way to define a value for f2fs_bug_on(), since it is only
> activated by CHECK_FS config.
>
> Thanks,
>
>> ret = -ENODATA;
>> goto stop;
>> }
>> --
>> 1.8.5.2
> .
>

--
Thanks,
Yunlong Song



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