Re: [PATCH v6 21/28] btrfs: disallow mixed-bg in HMZONED mode

Josef Bacik
2019-12-17T19:56:25Z

On 12/12/19 11:09 PM, Naohiro Aota wrote:
> Placing both data and metadata in a block group is impossible in HMZONED
> mode. For data, we can allocate a space for it and write it immediately
> after the allocation. For metadata, however, we cannot do so, because the
> logical addresses are recorded in other metadata buffers to build up the
> trees. As a result, a data buffer can be placed after a metadata buffer,
> which is not written yet. Writing out the data buffer will break the
> sequential write rule.
>
> This commit check and disallow MIXED_BG with HMZONED mode.
>
> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>

I would prefer it if you did all of the weird disallows early on so it's clear
as I go through that I don't have to think about certain cases. I remembered
from a previous look through that mixed_bg's were disallowed, but I had to go
look for some other cases.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef