Re: [PATCH] block: bios with an offset are always gappy

[Johannes Thumshirn]

On Thu, Apr 13, 2017 at 11:48:35AM +0200, Christoph Hellwig wrote:
> I think we should also turns this into a WARN_ON_ONCE + error return..
> 
> But do you have an exact btrfsprogs version and command line?  I do a lot
> of testing that involves mkfs.btrfs on nvme and haven't seen it..

Sure, it's:
mkfs.btrfs, part of btrfs-progs v4.5.3+20160729

Qemu is 2.6.2

[...]

> 
> I think the code in NVMe (and potentially the other drivers using
> virt_queue_boundary) is bogus.  All of them are actually fine with
> gaps in the protocol, as long as the gaps are aligned to said boundary.
> 
> So I suspect what we really need is to fix up NVMe, and after that
> we could even relax the above check, to not check for offset but
> offset & queue_virt_boundary(q).

That's what I tried doing the last two days but as we're rather late in the rc
cycle and it is a regression that came in with -rc1 I'd rather like to have it
fixed or at least have a band aid in place.

Byte,
	Johannes

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Johannes Thumshirn                                          Storage
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