On Thu, Jan 09, 2020 at 12:03:01PM -0800, Dan Williams wrote:
> So I'd find two options reasonably consistent:
> 1) Keep status quo where partitions are created and support DAX.
> 2) Stop partition creation altogether, if anyones wants to split pmem
> device further, he can use dm-linear for that (i.e., kpartx).
> But I'm not sure if the ship hasn't already sailed for option 2) to be
> feasible without angry users and Linus reverting the change.
Christoph? I feel myself leaning more and more to the "keep pmem
I don't see "drop partition support" effort ending well given the long
standing "ext4 fails to mount when dax is not available" precedent.
Do we have any evidence of existing setups with DAX and partitions?
Can we just throw in a patch to reject that case for now before actually
removing the code and see if anyone screams. And fix ext4 up while
we are at it.
I think the next least bad option is to have a dax_get_by_host()
variant that passes an offset and length pair rather than requiring a
later bdev_dax_pgoff() to recall the offset. This also prevents
needing to add another dax-device object representation.
IFF we have to keep partition support, yes. But keeping it just seems
like a really bad idea.