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

From: Jaegeuk Kim
Date: Mon Nov 06 2017 - 21:38:43 EST


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 <yunlong.song@xxxxxxxxxx>
> > > Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> > > ---
> > > 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.

Thanks,

>
> >
> > f2fs_bug_on(sbi, !total_freed && !sync && gc_type == FG_GC);
> >
> > > ret = -ENODATA;
> > > goto stop;
> > > }
> > > --
> > > 1.8.5.2
> > .
> >
>
> --
> Thanks,
> Yunlong Song
>