Re: [PATCH v4] f2fs: fix zoned block device information initialization

[Chao Yu <chao@kernel.org>]

On 2024/2/3 23:24, 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. If this value is 0,
> there is no limit.
> 
> Signed-off-by: Wenjie Qi <qwjhust@gmail.com>
> ---
>   fs/f2fs/f2fs.h  |  1 +
>   fs/f2fs/super.c | 21 +++++++++++++++++++++
>   2 files changed, 22 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 resources of the zoned device */
>   #endif
>   
>   	/* for node-related operations */
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 1b718bebfaa1..45e82d6016fc 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 && sbi->max_open_zones < F2FS_OPTION(sbi).active_logs) {
> +		f2fs_err(sbi,
> +			"zoned: max open zones %u is too small, need at least %u open zones",
> +				 sbi->max_open_zones, F2FS_OPTION(sbi).active_logs);
> +		err = -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 = 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 = bdev_max_open_zones(bdev);

Wenjie,

max_open_zones can always be zero? then sbi->max_open_zones will be zero,
is this a valid case?

Thanks,

> +	if (max_open_zones && (max_open_zones < sbi->max_open_zones || !sbi->max_open_zones))
> +		sbi->max_open_zones = max_open_zones;
> +	if (sbi->max_open_zones && sbi->max_open_zones < F2FS_OPTION(sbi).active_logs) {
> +		f2fs_err(sbi,
> +			"zoned: max open zones %u is too small, need at least %u open zones",
> +				 sbi->max_open_zones, F2FS_OPTION(sbi).active_logs);
> +		return -EINVAL;
> +	}
> +
>   	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");