Re: [PATCH 4/6] fs: xfs: Support atomic write for statx

From: Ojaswin Mujoo
Date: Mon Feb 12 2024 - 07:11:30 EST

On Fri, Feb 09, 2024 at 05:30:50PM +0000, John Garry wrote:
> The same goes for atomic write boundary in NVMe. Currently we say that it
> needs to be a power-of-2. However, it really just needs to be a multiple of
> awu_max. So if some HW did report a !power-of-2 atomic write boundary, we

Hey John, sorry for double reply but can you point out where this
requrement is stated in the spec?

For example in NVME Command Set spec I can see that

> The boundary size shall be greater than or equal to the corresponding
> atomic write size

However I'm not able to find the multiple-of-unit-max reqirement in the
spec. Maybe I'm missing something?


> could reduce awu_max reported until to fits the power-of-2 rule and also is
> cleanly divisible into atomic write boundary. But that is just not what HW
> will report (I expect). We live in a power-of-2 data granularity world.