On Tue, 11 Aug 2015, Christoph Hellwig wrote:
This series adds support for a simplified Persistent Reservation API to the block layer. The intent is that both in-kernel and userspace consumers can use the API instead of having to hand craft SCSI or NVMe command through the various pass through interfaces. It also adds DM support as getting reservations through dm-multipath is a major pain with the current scheme. NVMe support currently isn't included as I don't have a multihost NVMe setup to test on, but Keith offered to test it and I'll have a patch for it shortly.
Hi Christoph, I wrote an nvme implementation and it seems to work as expected with your pr-tests (minor modification to open an nvme target). While API appears to work as designed, there are a few features of NVMe that are unreachable with it. For example, NVMe can ignore existing keys when acquiring a reservation in addition to registering a new key. NVMe can also specify if whether or not a reservation should persist through power-loss. Anyway, I don't think SCSI has these same options. Should this new IOCTL API accommodate the common subset to maintain its simplicity, or make it more expressive for all features? The more important question might be if there are any users requiring these features, and I honestly don't know that right now. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
