Re: [RESEND PATCH] dm-ebs: Mark full buffer dirty even on partial write

From: Christoph Hellwig

Date: Fri Nov 21 2025 - 02:24:27 EST


On Thu, Nov 20, 2025 at 01:08:57PM +0100, Uladzislau Rezki wrote:
> Could you please check below? Is the last one is correctly reported?

The latter looks unexpected, but is is becase qemu is not passing through
the qemu physical_block_size attribute to any of the nvme settings Linux
interprets as such for NVMe (NVMe doesn't actually have the concept of
a physical block size, unlike SCSI/ATA):

root@testvm:~# nvme id-ns -H /dev/nvme0n1 | grep npw
npwg : 0
npwa : 0
root@testvm:~# nvme id-ns -H /dev/nvme0n1 | grep naw
nawun : 0
nawupf : 0
root@testvm:~# nvme id-ctrl -H /dev/nvme0 | grep awupf
awupf : 0

but as said multiple times, that should not really matter - the logical
block size is the granularity of I/O, the physical block size is just
a performance hint.