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From: Wenjie Qi <qwjhust@gmail.com>
Date: Sun, 4 Feb 2024 15:29:16 +0800
Message-ID: <CAGFpFsQevfTzirUyn7=5UOwrbwWo3SKnS_Sa7TQWXi3O6KSzMw@mail.gmail.com>
Subject: Re: [PATCH v5] f2fs: fix zoned block device information initialization
To: Yongpeng Yang <yangyongpeng1@oppo.com>
Cc: jaegeuk@kernel.org, chao@kernel.org, 
	linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, 
	hustqwj@hust.edu.cn
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On Sun, Feb 4, 2024 at 12:53=E2=80=AFPM Yongpeng Yang <yangyongpeng1@oppo.c=
om> wrote:
>
> 1. f2fs_scan_devices call init_blkz_info for each zoned device, is it
> reasonable that every device need to have 6 open zones at least?

Because it is possible for all active logs to write to the same zoned
device at the same time,
each zoned device must have at least the same number of open zone
resources as active logs.

> 2. we should add all open_zones of every zoned device to
> sbi->max_open_zones, sbi->max_open_zones will be UINT_MAX or accumulated
> open_zones. Is it more reasonable?

I don't think that's right.
sbi->max_open_zone is the number of resources that are the least of
all zoned devices.

Thanks.

>
>
> On 2/4/2024 11:10 AM, Wenjie Qi wrote:
> > If the max open 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.
> >
> > Signed-off-by: Wenjie Qi <qwjhust@gmail.com>
> > ---
> >   fs/f2fs/f2fs.h  |  1 +
> >   fs/f2fs/super.c | 24 ++++++++++++++++++++++++
> >   2 files changed, 25 insertions(+)
> >
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 543898482f8b..161107f2d3bd 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1558,6 +1558,7 @@ struct f2fs_sb_info {
> >
> >   #ifdef CONFIG_BLK_DEV_ZONED
> >       unsigned int blocks_per_blkz;           /* F2FS blocks per zone *=
/
> > +     unsigned int max_open_zones;            /* max open zone resource=
s of the zoned device */
> >   #endif
> >
> >       /* for node-related operations */
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 1b718bebfaa1..c6709efbc294 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -2388,6 +2388,16 @@ static int f2fs_remount(struct super_block *sb, =
int *flags, char *data)
> >       if (err)
> >               goto restore_opts;
> >
> > +#ifdef CONFIG_BLK_DEV_ZONED
> > +     if (sbi->max_open_zones < F2FS_OPTION(sbi).active_logs) {
> > +             f2fs_err(sbi,
> > +                     "zoned: max open zones %u is too small, need at l=
east %u open zones",
> > +                              sbi->max_open_zones, F2FS_OPTION(sbi).ac=
tive_logs);
> > +             err =3D -EINVAL;
> > +             goto restore_opts;
> > +     }
> > +#endif
> > +
> >       /* flush outstanding errors before changing fs state */
> >       flush_work(&sbi->s_error_work);
> >
> > @@ -3930,11 +3940,22 @@ static int init_blkz_info(struct f2fs_sb_info *=
sbi, int devi)
> >       sector_t nr_sectors =3D bdev_nr_sectors(bdev);
> >       struct f2fs_report_zones_args rep_zone_arg;
> >       u64 zone_sectors;
> > +     unsigned int max_open_zones;
> >       int ret;
> >
> >       if (!f2fs_sb_has_blkzoned(sbi))
> >               return 0;
> >
> > +     max_open_zones =3D bdev_max_open_zones(bdev);
> > +     if (max_open_zones && (max_open_zones < sbi->max_open_zones))
> > +             sbi->max_open_zones =3D max_open_zones;
> > +     if (sbi->max_open_zones < F2FS_OPTION(sbi).active_logs) {
> > +             f2fs_err(sbi,
> > +                     "zoned: max open zones %u is too small, need at l=
east %u open zones",
> > +                              sbi->max_open_zones, F2FS_OPTION(sbi).ac=
tive_logs);
> > +             return -EINVAL;
> > +     }
> > +
> >       zone_sectors =3D 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");
> > @@ -4253,6 +4274,9 @@ static int f2fs_scan_devices(struct f2fs_sb_info =
*sbi)
> >
> >       logical_blksize =3D bdev_logical_block_size(sbi->sb->s_