Re: [f2fs-dev] [PATCH] f2fs: update dirty status for CURSEG as well

[Yunlong Song]

Correct, I will update the patch.

On 2017/10/13 19:08, Chao Yu wrote:
> Hi Yunlong,
>
> On 2017/10/11 21:25, Yunlong Song wrote:
> > Without this patch, it will cause all the free segments using up in some
> > corner case. For example, there are 100 segments, and 20 of them are
> > reserved for ovp. If 79 segments are full of data, segment 80 becomes
> > CURSEG segment, write 512 blocks and then delete 511 blocks. Since it is
> > CURSEG segment, the __locate_dirty_segment will not update its dirty
> > status. Then the dirty_segments(sbi) is 0, f2fs_gc will fail to
> > get_victim, and f2fs_balance_fs will fail to trigger gc action. After
> > f2fs_balance_fs returns, f2fs can continue to write data to segment 81.
> > Again, segment 81 becomes CURSEG segment, write 512 blocks and delete
> > 511 blocks, the dirty_segments(sbi) is 0 and f2fs_gc fail again. This
> > can finally use up all the free segments and cause panic.
> Should we also remove the check in locate_dirty_segment?
>
> Thanks,
>
> > Signed-off-by: Yunlong Song <yunlong.song@xxxxxxxxxx>
> > ---
> >   fs/f2fs/segment.c | 4 ----
> >   1 file changed, 4 deletions(-)
> >
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index bfbcff8..0ff52d5 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -686,10 +686,6 @@ static void __locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno,
> >   {
> >   	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
> >   
> > -	/* need not be added */
> > -	if (IS_CURSEG(sbi, segno))
> > -		return;
> > -
> >   	if (!test_and_set_bit(segno, dirty_i->dirty_segmap[dirty_type]))
> >   		dirty_i->nr_dirty[dirty_type]++;
> >   
> .

--
Thanks,
Yunlong Song