On Thu, Jan 16, 2014 at 02:54:29PM -0200, Carlos Maiolino wrote: > > I'm not sure if the decision regarding which solution to use (restricted or > host-aware) was already made (I didn't find any doc specifying it, but in > either case, having these values properly exported and I'm not sure Ted, if you > had the idea to describe above all geometry information we'd like to have > exported, but if you did, one thing I believe to be very important to us is to > have a way to retrieve the specific location of the random write zones, so > filesystems can take advantage of this for some specific metadata workloads. At least initially, it will definitely be host-aware. Even if we can make all of our metadata be fully SMR-friendly, it's not going to deal with random read/write updates. So it's likely that for ext4, the first step is to make the metadata be SMR-friendly. The second step will be to tweak block allocation to be SMR-friendly. Only then would we try to support random writes where in a SMR-friendly way --- and it's not clear to me it makes sense for us to take things that far, and that would be a prereq before we could take ext4 to support restricted mode (aka host-managed SMR). Part of what we will need to support file systems will indeed be a way to export geometry information to userspace. As I noted, I'm also interested in exporting support for the ZBC commands to userspace, since there may be some use cases where the application will manage the SMR zones, either using a raw block device, or using ext4 to manage the large files which are aligned with SMR zones. Cheers, - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
