Re: [PATCH v5 03/28] btrfs: Check and enable HMZONED mode

[Johannes Thumshirn <jthumshirn@suse.de>]

On Wed, Dec 04, 2019 at 05:17:10PM +0900, Naohiro Aota wrote:
> HMZONED mode cannot be used together with the RAID5/6 profile for now.
> Introduce the function btrfs_check_hmzoned_mode() to check this. This
> function will also check if HMZONED flag is enabled on the file system and
> if the file system consists of zoned devices with equal zone size.

I have a question, you wrote you check for a file system consisting of zoned
devices with equal zone size. What happens if you create a multi device file
system combining zoned and regular devices? Is this even supported and if no
where are the checks for it?

[...]

> +int btrfs_check_hmzoned_mode(struct btrfs_fs_info *fs_info)
> +{
> +	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
> +	struct btrfs_device *device;
> +	u64 hmzoned_devices = 0;
> +	u64 nr_devices = 0;
> +	u64 zone_size = 0;
> +	int incompat_hmzoned = btrfs_fs_incompat(fs_info, HMZONED);
> +	int ret = 0;
> +
> +	/* Count zoned devices */
> +	list_for_each_entry(device, &fs_devices->devices, dev_list) {
> +		if (!device->bdev)
> +			continue;

Nit:
		enum blk_zoned_model zone_model = blk_zoned_model(device->bdev);

		if (zone_model == BLK_ZONED_HM ||
		    zone_model == BLK_ZONED_HA &&
		    incompat_hmzoned) {

> +		if (bdev_zoned_model(device->bdev) == BLK_ZONED_HM ||
> +		    (bdev_zoned_model(device->bdev) == BLK_ZONED_HA &&
> +		     incompat_hmzoned)) {
> +			hmzoned_devices++;
> +			if (!zone_size) {
> +				zone_size = device->zone_info->zone_size;
> +			} else if (device->zone_info->zone_size != zone_size) {
> +				btrfs_err(fs_info,
> +					  "Zoned block devices must have equal zone sizes");
> +				ret = -EINVAL;
> +				goto out;
> +			}
> +		}
> +		nr_devices++;
> +	}