On 9/26/2024 8:37 PM, Keith Busch wrote: > On Thu, Feb 01, 2024 at 06:31:25PM +0530, Kanchan Joshi wrote: >> Block layer integrity processing assumes that protection information >> (PI) is placed in the first bytes of each metadata block. >> >> Remove this limitation and include the metadata before the PI in the >> calculation of the guard tag. > > Very late reply, but I am just now discovering the consequences of this > patch. > > We have drives with this format, 64b metadata with PI at the end. With > previous kernels, we had written data to these drives. Those kernel > versions disabled the GUARD generation, so the metadata was written > without it, and everything was fine. > > Now we upgrade to 6.9+, and this kernel enables the GUARD check. All the > data previously written to this drive is unreadable because the GUARD is > invalid. > > Not sure exactly what to do about this, but it is a broken kernel > upgrade path, so wanted to throw that information out there. > Ah, writing to the disk without any guard, but after that reading with the guard! I wish if there was a way to format the NVMe only to reset its pi type (from non-zero to 0). But there are kernel knobs too. Hope you are able to get to the same state (as nop profile) by clearing write_generate and read_verify: echo 0 > /sys/block/nvme0n1/integrity/read_verify
