aborted SCSI commands while discarding/unmapping via mkfs.xfs

[Stefan Priebe <s.priebe@xxxxxxxxxxxx>]

Hello list,

i'm testing KVM with qemu, libiscsi, virtio-scsi-pci and scsi-general on 
top of a nexenta storage solution. While doing mkfs.xfs on an already 
used LUN / block device i discovered that the unmapping / discard 
commands mkfs.xfs sends take a long time which results in a lot of 
aborted scsi commands.
Would it make sense to let mkfs.xfs send these unmapping commands in 
small portations (f.e. 100MB) or is there another problem in the patch 
to the block device? Any suggestions or ideas?
Thanks!

Greets,
Stefan