Re: bio re-ordering

From: Peter Jeremy <>
Date: Wed, 02 Feb 2022 07:49:31 UTC
Thanks all for the very prompt responses.

On 2022-Jan-28 22:32:02 -0700, Warner Losh <> wrote:
>I think that ufs relies on two ordering primitives, both marked with
>That's what most of the drivers key off of. We always set BIO_ORDERED on
>all the BIO_FLUSH
>events as far as I Can tell.

Thanks for that warning.  I don't think geom_gate understands either
B_BARRIER or BIO_ORDERED.  I shall have a closer look.

>to it. b*barrierwrite() sets this, and that's used in the ffs_alloc code.

In my case, I'm interested in ZFS, rather than UFS and it doesn't seem
to set B_BARRIER or BIO_ORDERED or indirectly.

Peter Jeremy