Re: [PATCH v2 1/2] btrfs: zoned: do not remove unwritten non-data block group

[Johannes Thumshirn <Johannes.Thumshirn@wdc.com>]

On 11.07.25 09:12, Naohiro Aota wrote:
> There are some reports of "unable to find chunk map for logical 2147483648
> length 16384" error message appears in the dmesg. This means some IOs are
                                   s/the// ~^
> occurring after a block group is removed.
> 
> When a metadata tree node is cleaned on the zoned setup, we keep that node
                                       s/the/a ~^
> still dirty and write it out not to create a write hole. However, this can
> make a block group's used bytes == 0 while there is dirty region left.
                                        a dirty region ~^
> 
> Such unused block group is moved into the unused_bg list and processed for
Such an unused

> the removal. When the removal succeeds, the block group is removed from the
   ^~ s/the//
> transaction->dirty_bgs list, so the unused dirty nodes in the block group
> are not sent at the transaction commit time. It will be written at some
> later time e.g, sync or umount, and causes the "unable to find chunk map"

s/the// ~^

> errors.
> 
> This can happen relatively easier on SMR whose zone size is 256MB. However,
s/easier/easy/

> calling do_zone_finish() on such block group returns -EAGAIN and keep that
> block group intact, which is why the issue is hidden until now.
> 
> Fixes: afba2bc036b0 ("btrfs: zoned: implement active zone tracking")
> CC: stable@vger.kernel.org # 6.1+
> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>

Sorry for not spotting these in v1. But I think they can be fixed up 
when applying.

Otherwise looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>