Re: [PATCH v2] f2fs: fix max open zone constraints

[Wenjie Qi]

Hello Jaegeuk,

Thank you for your suggestions. I have split this patch into three patches.
Here is a link to the latest email list.
The [1] of these links is the patch for the third point above.

[1] https://lore.kernel.org/linux-f2fs-devel/CAGFpFsT6XyTNPRxrTg+=F_eQ_-cryhdYd-k7rXxy1oJn4F4oLA@xxxxxxxxxxxxxx/T/#t
[2] https://lore.kernel.org/linux-f2fs-devel/CAGFpFsTJAJXjrkRT2n9oFHCMW-V3BgVmouR_8-GD4ZqxC2n_nw@xxxxxxxxxxxxxx/T/#t
[3] https://lore.kernel.org/linux-f2fs-devel/cedb4875-5795-4789-a010-a9c66fa61707@xxxxxxxx/T/#t


On Sat, Jan 27, 2024 at 7:08 AM Jaegeuk Kim <jaegeuk@xxxxxxxxxx> wrote:
>
> On 01/09, Wenjie wrote:
> > From: Wenjie Qi <qwjhust@xxxxxxxxx>
> >
> > 1. If the max active zones of zoned devices are less than
> > the active logs of F2FS, the device may error due to
> > insufficient zone resources when multiple active logs are
> > being written at the same time.
> >
> > 2. We can get the number of remaining available zone
> > resources by subtracting the number of active logs from
> > the number of max active zones of zoned devices.  We can
> > use these available zone resources to reduce the number
> > of pending bio when switching zones.
> >
> > 3. The original code for determining zone end was
> > after "out":, which would have missed some fio's
> > where is_end_zone_blkaddr(sbi, fio->new_blkaddr)
> > was true. I've moved this code before "skip:" to
> > make sure it's done for each fio.
>
> Could you please keep #3 as a separate patch?
>
> >
> > Signed-off-by: Wenjie Qi <qwjhust@xxxxxxxxx>
> > ---
> >  fs/f2fs/data.c  | 38 ++++++++++++++++++++++++++++----------
> >  fs/f2fs/f2fs.h  |  2 ++
> >  fs/f2fs/super.c |  9 +++++++++
> >  3 files changed, 39 insertions(+), 10 deletions(-)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index dce8defdf4c7..6b11364e94b8 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -392,6 +392,19 @@ static void f2fs_zone_write_end_io(struct bio *bio)
> >       complete(&io->zone_wait);
> >       f2fs_write_end_io(bio);
> >  }
> > +
> > +static void f2fs_zone_write_end_io_nowait(struct bio *bio)
> > +{
> > +#ifdef CONFIG_F2FS_IOSTAT
> > +     struct bio_iostat_ctx *iostat_ctx = bio->bi_private;
> > +     struct f2fs_sb_info *sbi = iostat_ctx->sbi;
> > +#else
> > +     struct f2fs_sb_info *sbi = (struct f2fs_sb_info *)bio->bi_private;
> > +#endif
> > +
> > +     atomic_inc(&sbi->available_active_zones);
> > +     f2fs_write_end_io(bio);
> > +}
> >  #endif
> >
> >  struct block_device *f2fs_target_device(struct f2fs_sb_info *sbi,
> > @@ -1080,22 +1093,27 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> >       io->last_block_in_bio = fio->new_blkaddr;
> >
> >       trace_f2fs_submit_page_write(fio->page, fio);
> > -skip:
> > -     if (fio->in_list)
> > -             goto next;
> > -out:
> >  #ifdef CONFIG_BLK_DEV_ZONED
> >       if (f2fs_sb_has_blkzoned(sbi) && btype < META &&
> >                       is_end_zone_blkaddr(sbi, fio->new_blkaddr)) {
> > -             bio_get(io->bio);
> > -             reinit_completion(&io->zone_wait);
> > -             io->bi_private = io->bio->bi_private;
> > -             io->bio->bi_private = io;
> > -             io->bio->bi_end_io = f2fs_zone_write_end_io;
> > -             io->zone_pending_bio = io->bio;
> > +             if (!atomic_add_negative(-1, &sbi->available_active_zones)) {
> > +                     io->bio->bi_end_io = f2fs_zone_write_end_io_nowait;
> > +             } else {
> > +                     atomic_inc(&sbi->available_active_zones);
> > +                     bio_get(io->bio);
> > +                     reinit_completion(&io->zone_wait);
> > +                     io->bi_private = io->bio->bi_private;
> > +                     io->bio->bi_private = io;
> > +                     io->bio->bi_end_io = f2fs_zone_write_end_io;
> > +                     io->zone_pending_bio = io->bio;
> > +             }
> >               __submit_merged_bio(io);
> >       }
> >  #endif
> > +skip:
> > +     if (fio->in_list)
> > +             goto next;
> > +out:
> >       if (is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN) ||
> >                               !f2fs_is_checkpoint_ready(sbi))
> >               __submit_merged_bio(io);
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 65294e3b0bef..1b1833e1d10e 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1551,6 +1551,8 @@ struct f2fs_sb_info {
> >
> >  #ifdef CONFIG_BLK_DEV_ZONED
> >       unsigned int blocks_per_blkz;           /* F2FS blocks per zone */
> > +     unsigned int max_active_zones;          /* max zone resources of the zoned device */
> > +     atomic_t available_active_zones;                /* remaining zone resources */
> >  #endif
> >
> >       /* for node-related operations */
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 206d03c82d96..c79919425d63 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -3932,6 +3932,15 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
> >       if (!f2fs_sb_has_blkzoned(sbi))
> >               return 0;
> >
> > +     sbi->max_active_zones = bdev_max_active_zones(bdev);
> > +     if (sbi->max_active_zones && (sbi->max_active_zones < F2FS_OPTION(sbi).active_logs)) {
> > +             f2fs_err(sbi,
> > +                     "zoned: max active zones %u is too small, need at least %u active zones",
> > +                              sbi->max_active_zones, F2FS_OPTION(sbi).active_logs);
> > +             return -EINVAL;
> > +     }
> > +     atomic_set(&sbi->available_active_zones, sbi->max_active_zones - F2FS_OPTION(sbi).active_logs);
> > +
> >       zone_sectors = bdev_zone_sectors(bdev);
> >       if (!is_power_of_2(zone_sectors)) {
> >               f2fs_err(sbi, "F2FS does not support non power of 2 zone sizes\n");
> > --
> > 2.34.1