On Fri, Aug 25, 2017 at 11:01:55AM +1000, Dave Chinner wrote: > On Thu, Aug 24, 2017 at 08:04:41PM +0200, Luis R. Rodriguez wrote: > > While all this is nice, I'm sure we're all aware of the dangers of setting > > things in stone through sysfs, its likely already decided for the above > > tunables, but adding a uevent *is* yet another layer of user interface > > which userspace can *expect* and we should be certain we want this so > > we won't regress userspace later. > > > > Just saying, we better damn be sure this is the way we want to go. > > I'm not sure what you are trying to warn us about? :/ > > These are events on an XFS specific kobj, it's not a generic VFS > filesystem event we are generating here. It's no different from a > hardware device generating it's own uevents to tell userspace > something changed in the device. I meant that once its sent even if it is XFS specific, it will be something that some userspace can expect and then we'd always have to send it later. > A quick grep would have told you that GFS2 already has it's own > online/offline uevents (e.g. gfs2_online_uevent()), as does the > DLM code. Orangefs seems to use quite a few of uevent notifications, > too. So it's not like we're doing something controversial or unique > here, nor something that locks us out of a non-existent VFS event > notification mechanism. I don't think its controversial *at all*. Just that a mount uevent, with uuid, sounds like something we could at least agree is pretty generic. Regardless of what we end up doing with it or how. Luis
