Re: [GIT PULL] bcachefs changes for 6.17

From: Kent Overstreet
Date: Tue Aug 12 2025 - 16:05:34 EST


On Tue, Aug 12, 2025 at 01:35:56PM -0600, Keith Busch wrote:
> On Mon, Aug 11, 2025 at 10:26:03AM -0400, Kent Overstreet wrote:
> > On the other hand, for the only incidences I can remotely refer to in
> > the past year and a half, there has been:
> ...
>
> > - the block layer developer who went on a four email rant where he,
> > charitably, misread the spec or the patchset or both; all this over a
> > patch to simply bring a warning in line with the actual NVME and SCSI
> > specs.
>
> Are you talking about this thread?
>
> https://lore.kernel.org/linux-block/20250311201518.3573009-14-kent.overstreet@xxxxxxxxx/
>
> I try to closely follow those lists, and that's the only thread I recall
> that even slightly rings a bell from your description, however it's not
> an accurate description (you were the one who misread the specs there; I
> tried to help bridge the gap). I recall the interaction was pretty tame
> though, so maybe you're talking about something else. Perhaps a link for
> context if I got it wrong?

I've since seen a lot of actual test data from SCSI hard drives - fua
reads are definitely not cached, without exception across manufacturers.

On NVME the situation is much murkier.