Re: [f2fs-dev] [PATCH] f2fs-tools: allocate logs after conventional area for HM zoned devices

[Chao Yu]

On 2024/1/26 0:25, Daeho Jeong wrote:
> On Wed, Jan 24, 2024 at 7:34 PM Chao Yu <chao@xxxxxxxxxx> wrote:
> > +Cc Yongpeng Yang
> >
> > Daeho,
> >
> > Yongpeng reports a potential issue: if c.devices[0].total_segments is
> > larger than segments of mainarea, c.cur_seg[CURSEG_HOT_NODE] will exceed
> > end boundary of mainarea. Could you please check that? though it's a corner
> > case.
>
> Can you elaborate more?

Since c.cur_seg[CURSEG_HOT_NODE] is an offset started from main_blkaddr.
If c.cur_seg[CURSEG_HOT_NODE] was assigned w/ c.devices[0].total_segments,
and c.devices[0].total_segments is larger than segments of mainare,
c.cur_seg[CURSEG_HOT_NODE] will exceed the end boundary of mainarea.

	c.cur_seg[CURSEG_HOT_NODE] = c.zoned_model == F2FS_ZONED_HM ?
			c.devices[0].total_segments : 0;

> In the case of F2FS_ZONED_HM, we have the devices[1].
> Do you mean the case we format the filesystem intentionally smaller
> than what devices have?

I mean blew case:
device[0]: conventional device size = 10240 MB
device[1]: zone device size = 2 MB

Thanks,

> > On 2024/1/18 7:00, Daeho Jeong wrote:
> > > From: Daeho Jeong <daehojeong@xxxxxxxxxx>
> > >
> > > Make to allocate logs after conventional area for HM zoned devices to
> > > spare them for file pinning support.
> > >
> > > Signed-off-by: Daeho Jeong <daehojeong@xxxxxxxxxx>
> > > ---
> > >    mkfs/f2fs_format.c | 3 ++-
> > >    1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c
> > > index f2840c8..91a7f4b 100644
> > > --- a/mkfs/f2fs_format.c
> > > +++ b/mkfs/f2fs_format.c
> > > @@ -557,7 +557,8 @@ static int f2fs_prepare_super_block(void)
> > >                c.cur_seg[CURSEG_COLD_DATA] = 0;
> > >                c.cur_seg[CURSEG_WARM_DATA] = next_zone(CURSEG_COLD_DATA);
> > >        } else if (c.zoned_mode) {
> > > -             c.cur_seg[CURSEG_HOT_NODE] = 0;
> > > +             c.cur_seg[CURSEG_HOT_NODE] = c.zoned_model == F2FS_ZONED_HM ?
> > > +                     c.devices[0].total_segments : 0;
> > >                c.cur_seg[CURSEG_WARM_NODE] = next_zone(CURSEG_HOT_NODE);
> > >                c.cur_seg[CURSEG_COLD_NODE] = next_zone(CURSEG_WARM_NODE);
> > >                c.cur_seg[CURSEG_HOT_DATA] = next_zone(CURSEG_COLD_NODE);