Re: [f2fs-dev] [PATCH v3] f2fs: fix zoned block device information initialization

[Chao Yu <chao@kernel.org>]

On 2024/1/23 17:18, Yongpeng Yang wrote:
> Hi Wenjie,
> It seems more reasonable to use bdev_max_open_zones instead of
> bdev_max_active_zones.

Hi all,

I guess it needs to be initialized w/ bdev_max_open_zones(), due
to the max of open zones of zoned device limits the number of
zones that a host software can simultaneously write [1], right?

[1] https://zonedstorage.io/docs/introduction/zoned-storage#active-zones-limit

Thanks,

> 
> If an NVMe device has multiple namespaces, and the device contains a
> total of 11 open zones, two of the namespaces, nvme0n1 and nvme0n2, each
> correspond to an instance of the F2FS filesystem, and both filesystem
> instances can be initialized successfully. Since multiple namespaces
> share all open zones, the number of open zones is not equal to the
> number of open zones available to F2FS in a multi-namespace scenario.
> This patch does not yet cover this scenario.
> 
> On 1/23/2024 4:12 PM, Wenjie Qi wrote:
>> 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. 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 | 18 ++++++++++++++++++
>>    2 files changed, 19 insertions(+)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 65294e3b0bef..669f84f6b0e5 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -1551,6 +1551,7 @@ 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 */
>>    #endif
>>    
>>    	/* for node-related operations */
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index 206d03c82d96..aef41b54098c 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -2385,6 +2385,16 @@ 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_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);
>> +		err = -EINVAL;
>> +		goto restore_opts;
>> +	}
>> +#endif
>> +
>>    	/* flush outstanding errors before changing fs state */
>>    	flush_work(&sbi->s_error_work);
>>    
>> @@ -3932,6 +3942,14 @@ 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;
>> +	}
>> +
>>    	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");