Re: [PATCH v2] f2fs: collect prefree segments to avoild write checkpoint fail

[Yunlong Song]

So I use CHECK_FS config to control it. When CHECK_FS is off, all the 
other f2fs_bug_on also
only printk WARNING info rather than trigger BUG_ON.

On 2017/10/31 9:59, Chao Yu wrote:
> On 2017/10/31 9:33, Yunlong Song wrote:
> > ping...
> >
> > On 2017/9/1 20:00, Yunlong Song wrote:
> > > In come corner case, the reserved segments are used to do gc, and there are
> > > not enough free segments for write checkpoint to finish its job, then the
> > > gc process will fail to change the prefree segments to free segments.
> I agreed to use this in production for robustness, but for upstream, it's better
> to investigate and fix this issue rather than covering up it.
>
> Thanks,
>
> > > Signed-off-by: Yunlong Song <yunlong.song@xxxxxxxxxx>
> > > ---
> > >    fs/f2fs/gc.c | 10 ++++++++++
> > >    1 file changed, 10 insertions(+)
> > >
> > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > > index cd147e7..6552b04 100644
> > > --- a/fs/f2fs/gc.c
> > > +++ b/fs/f2fs/gc.c
> > > @@ -1056,6 +1056,16 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
> > >    	if (!sync) {
> > >    		if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
> > >    			segno = NULL_SEGNO;
> > > +#ifndef CONFIG_F2FS_CHECK_FS
> > > +			if (prefree_segments(sbi) &&
> > > +				has_not_enough_free_secs(sbi,
> > > +					reserved_sections(sbi), 0)) {
> > > +				ret = write_checkpoint(sbi, &cpc);
> > > +				if (ret)
> > > +					goto stop;
> > > +				sec_freed = 0;
> > > +			}
> > > +#endif
> > >    			goto gc_more;
> > >    		}
> > >    
>
> .

--
Thanks,
Yunlong Song