Hi, On Fri, Sep 09, 2016 at 10:02:03PM +0200, Wouter Verhelst wrote: > I see some practical problems with this: [...] One more that I didn't think about earlier: A while back, we spent quite some time defining the semantics of the various commands in the face of the NBD_CMD_FLUSH and NBD_CMD_FLAG_FUA write barriers. At the time, we decided that it would be unreasonable to expect servers to make these write barriers effective across different connections. Since my knowledge of kernel internals is limited, I tried finding some documentation on this, but I guess that either it doesn't exist or I'm looking in the wrong place; therefore, am I correct in assuming that blk-mq knows about such semantics, and will handle them correctly (by either sending a write barrier to all queues, or not making assumptions about write barriers that were sent over a different queue)? If not, this may be something that needs to be taken care of. Thanks, -- < ron> I mean, the main *practical* problem with C++, is there's like a dozen people in the world who think they really understand all of its rules, and pretty much all of them are just lying to themselves too. -- #debian-devel, OFTC, 2016-02-12 -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html