On Mon, Sep 25, 2017 at 04:05:17PM +0200, Hannes Reinecke wrote: > On 09/25/2017 03:50 PM, Christoph Hellwig wrote: > > On Mon, Sep 25, 2017 at 03:47:43PM +0200, Hannes Reinecke wrote: > >> Can't we make the multipath support invisible to the host? > >> IE check the shared namespaces before creating the device node, and just > >> move them under the existing namespaces if one exists? > > > > That was what my first version did, but various people talked me > > out of it. Unfortunately just multiplexing breaks a few things, > > including the userspace passthrough ioctls. > > > Care to give some specifics? > How would userspace passthrough be affected? Ioctls aside, if you've only one disk handle, it's a little difficult to compare iostats on each path, which can be useful for diagnosing issues. > I would've thought that we're sending the ioctl down one path, and we'd > be getting the completion back on the same path/queue/whatever. > (Unless we're talking multi-command ioctls, but those are evil anyway)
