Re: [PATCH] btrfs: zoned: handle RAID profiles in btrfs_can_activate_zone()

[Boris Burkov <boris@bur.io>]

On Mon, Aug 24, 2026 at 06:19:10PM +0200, Johannes Thumshirn wrote:
> btrfs_can_activate_zone() only accounts for the single and DUP profiles.
> For a RAID0, RAID1, RAID1C3, RAID1C4 or RAID10 block group the profile
> switch matches no case, so 'ret' stays false and the function reports
> that no zone can be activated, even when the devices have plenty of
> active zones left.
> 
> As a side effect BTRFS_FS_NEED_ZONE_FINISH gets set and, since
> btrfs_can_activate_zone() bails out early once that bit is set, data
> allocations will fail permanently: writers loop on -EAGAIN and hang in
> btrfs_new_extent_direct() waiting for the bit to clear.
> 
> Each of these profiles needs one active zone per device, just like
> single, so handle them the same way.
> 
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Boris Burkov <boris@bur.io>
> ---
>  fs/btrfs/zoned.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> index 9d448cdd60c4..107833fcf2be 100644
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -2689,6 +2689,11 @@ bool btrfs_can_activate_zone(struct btrfs_fs_devices *fs_devices, u64 flags)
>  
>  		switch (flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
>  		case 0: /* single */
> +		case BTRFS_BLOCK_GROUP_RAID0:
> +		case BTRFS_BLOCK_GROUP_RAID1:
> +		case BTRFS_BLOCK_GROUP_RAID1C3:
> +		case BTRFS_BLOCK_GROUP_RAID1C4:
> +		case BTRFS_BLOCK_GROUP_RAID10:
>  			ret = (atomic_read(&zinfo->active_zones_left) >= (1 + reserved));
>  			break;
>  		case BTRFS_BLOCK_GROUP_DUP:
> -- 
> 2.55.0
>