On Tuesday 15 October 2002 09:52, Kevin Corry wrote: > Also, am I correct in assuming that for merge_bvec_fn() to work properly, a > driver's merge_bvec_fn() must also call the merge_bvec_fn() of the driver > below it? For example, lets say we have a DM linear device that maps to two > underlying devices (or in LVM-speak, a linear LV that spans two PVs), both > of which are MD RAID-1 devices. For a given large request, DM may decide > that it is fully contained within one of its two target devices, and allow > all the requested pages to be added to the bio. However, it also needs to > ask MD what its limits are for that request, or MD would still have to go > through the trouble to split up the bio after it has been submitted. This example actually should have been RAID-0 (striping), not RAID-1 (mirroring). Sorry if this caused any confusion. -- Kevin Corry corryk@us.ibm.com http://evms.sourceforge.net/ _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
