Re: [Bug 1884831] Re: qemu-nbd fails to discard bigger chunks

[Eric Blake]

On 6/23/20 4:35 PM, Eric Blake wrote:
> Let's get nbd.ko out of the picture.  The problem can be reproduced in
> user space (here, where I built qemu-nbd to log trace messages to
> stderr):
>
> $ truncate --size=3G file
> $ qemu-nbd -f raw file --trace=nbd_\*
> $ nbdsh -u nbd://localhost:10810 -c 'h.trim(3*1024*1024*1024,0)'

> nbd.Error: nbd_trim: trim: command failed: Input/output error (EIO)

> so this is definitely a case of qemu as NBD server NOT honoring requests
> between 2G and 4G.  I'll have a patch posted soon.

https://lists.gnu.org/archive/html/qemu-devel/2020-07/msg06592.html

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org