On Mon, Jun 17, 2019 at 1:45 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > Again, I'd like to see SIGLOST sent to the application here. Are there > > any objections to reviving whatever patchset was in flight to add > > that? Or just writeup a new one? > > > > I think SIGLOST's utility is somewhat questionable. Applications will > need to be custom-written to handle it. If you're going to do that, then > it may be better to consider other async notification mechanisms. > inotify or fanotify, perhaps? Those may be simpler to implement and get > merged. The utility of SIGLOST is not well understood from the viewpoint of a local file system. The problem uniquely applies to distributed file systems. There simply is no way to recover from a lost lock for an application through POSIX mechanisms. We really need a new signal to just kill the application (by default) because recovery cannot be automatically performed even through system call errors. I don't see how inotify/fanotify (not POSIX interfaces!) helps here as it assumes the application will even use those system calls to monitor for lost locks when POSIX has no provision for that to happen. It's worth noting as well that the current behavior of the mount freezing on blacklist is not an acceptable status quo. The application will just silently stall the next time it tries to access the mount, if it ever does. -- Patrick Donnelly, Ph.D. He / Him / His Senior Software Engineer Red Hat Sunnyvale, CA GPG: 19F28A586F808C2402351B93C3301A3E258DD79D
