On April 11, 2016 5:10:47 PM PDT, ebied...@xmission.com wrote: >Linus Torvalds <torva...@linux-foundation.org> writes: > >> On Mon, Apr 11, 2016 at 4:37 PM, Eric W. Biederman >> <ebied...@xmission.com> wrote: >>> >>> My practical concern if we worked through the implementation details >>> would be how would it interact with people who bind mount >/dev/pts/ptmx >>> on top of /dev/ptmx. We might get some strange new errors. >> >> Yes, please don't let's play "clever" games. The semantics should be >> fairly straightforward. > >Actually for me this is about keeping the semantics simpler, and coming >up with a higher performance implementation. > >A dentry that does an automount is already well defined. > >Making the rule that accessing /dev/ptmx causes an automount of >/dev/pts/ptmx on top of the device node at /dev/ptmx is really simple, >with no special games. It also makes it more obvious to userspace what >is going on. AKA allows userspace to know which superblock does an >open >ptmx master tty belongs to (and it happens in a backwards and forwards >compatible way). > >My only concern is with this very minor change in semantics will >anything care. I need to implement and test to find out. > >I think I see an implementation that Al won't grumble too loudly about. > >Anyway I am going to try this and see what I can see. > >Eric
Why bother with an automount? You can look up ../ptmx from the devpts get_super method and just do the bind mount once. No fuss, no muss. What's wrong with that? -- Sent from my Android device with K-9 Mail. Please excuse brevity and formatting.
