On Mar 28 09:57, Michael Tokarev wrote:
> On 26.03.2026 11:23, Klaus Jensen wrote:
> > From: Pankaj Raghav <[email protected]>
> > 
> > dlfeat was changed from 0x9 to 0x1 when PI support was added.
> > It was removed because we can't rely on unmap and have to physically
> > clear it to get the checksums right but that doesnt mean that we do not
> > support the bit.
> > 
> > The spec says that if wzds is enabled, then the controller supports
> > deallocate (DEAC) on write zeroes. But DEAC bit in write zeroes command
> > is only a hint, the controller might choose to physically write zeroes in
> > those areas.
> > 
> > As we are sending write zeroes command with BDRV_REQ_MAY_UNMAP to the
> > underlying block device anyway (if the unmap operation is supported),
> > change the dlfeat value back to 0x9.
> > 
> > A new flag FALLOC_FL_WRITE_ZEROES has been introduced in linux for
> > fallocate which will use the wzds bit in dlfeat to quickly zeroout extents
> > using unmap operation whenever possible[1].
> > 
> > [1] 
> > https://lore.kernel.org/linux-fsdevel/[email protected]/
> > 
> > Fixes: 146f720c55 ("hw/block/nvme: end-to-end data protection")
> 
> Shouldn't this one be picked up for current qemu stable releases too?
> 
> I'm picking it up for 10.0 and 10.2 series, please let me know
> if I shouldn't.
> 

Michael,

Yes, please include in stable.

As always, thanks for being vigilant and picking this up!


Thanks,
Klaus

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