Messages in this thread | | | From | Kevin Corry <> | Subject | Re: [linux-lvm] Re: [PATCH] 2.5 version of device mapper submission | Date | Tue, 15 Oct 2002 10:06:09 -0500 |
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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/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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