[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-block] RFC: Tweak the NBD_OPT_SET_META_CONTEXT layout

From: Eric Blake
Subject: [Qemu-block] RFC: Tweak the NBD_OPT_SET_META_CONTEXT layout
Date: Sat, 31 Mar 2018 07:24:42 -0500
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0

As mentioned in earlier email threads, I experimented with an alternative layout to the structs sent across the wire during NBD_OPT_{LIST,SET}_META_CONTEXT, on the grounds that having the namespace and leaf-name combined into one string that requires further parsing on each end is not as nice as having two separate fields. I'm replying to this mail with two RFC patches, one for the NBD spec, and one for the qemu implementation.

If we like the idea, this has to go into qemu 2.12, so we have less than a week. Or, we can ignore the RFC, keep qemu the way it is currently coded, and when it is released, it will be time to promote the NBD extension-blockstatus to current as there will be an existing implementation to be interoperable with.

Note that I intentionally changed the value of NBD_OPT_SET_META_CONTEXT so that the existing Virtuozzo of OPT 10 will not get confused by the new layout (both new server and old client, as well as old server and new client, will merely fail to negotiate block status, and then be unable to use NBD_CMD_BLOCK_STATUS). I didn't bother changing NBD_OPT_LIST_META_CONTEXT, as it looks like the existing Virtuozzo implementation did not use that option as a client.

Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

reply via email to

[Prev in Thread] Current Thread [Next in Thread]