Re: [dm-devel] [PATCH 0/8] Use block pr_ops in LIO

[Bart Van Assche <bvanassche@acm.org>]

On 6/2/22 23:55, Mike Christie wrote:
> The following patches were built over Linus's tree. They allow us to use
> the block pr_ops with LIO's target_core_iblock module to support cluster
> applications in VMs.
> 
> Currently, to use something like windows clustering in VMs with LIO and
> vhost-scsi, you have to use tcmu or pscsi or use a cluster aware
> FS/framework for the LIO pr file. Setting up a cluster FS/framework is
> pain and waste when your real backend device is already a distributed
> device, and pscsi and tcmu are nice for specific use cases, but iblock
> gives you the best performance and allows you to use stacked devices
> like dm-multipath. So these patches allow iblock to work like pscsi/tcmu
> where they can pass a PR command to the backend module. And then iblock
> will use the pr_ops to pass the PR command to the real devices similar
> to what we do for unmap today.
> 
> Note that this is patchset does not attempt to support every PR SCSI
> feature in iblock. It has the same limitations as tcmu and pscsi where
> you can have a single I_T nexus per device and only supports what is
> needed for windows clustering right now.

How has this patch series been tested? Does LIO pass the libiscsi 
persistent reservation tests with this patch series applied?

Thanks,

Bart.