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

Johannes Thumshirn
2019-12-04T16:07:45Z

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++;
> + }