[illumos-Developer] Can only use "rdsk" for COMSTAR UNMAP support...

[Dan McDonald]

If I use the COMSTAR tools to use the block zvol device, UNMAP/DKIOCFREE
fails because spec_ioctl() fails on this check:

   1266 	if (vp->v_type != VCHR)
   1267 		return (ENOTTY);

If I use the character device (rdsk), everything works just fine.

It begs the higher-level question: Should there be an alternate DKIOCFREE
path for block devices?

Curious,
Dan