[RFC][PATCH 0/6] Enable multiple mounts of devpts
kyle at moffetthome.net
Tue Aug 5 20:32:33 PDT 2008
On Tue, Aug 5, 2008 at 2:15 AM, Eric W. Biederman <ebiederm at xmission.com> wrote:
>> There definitely needs to be a mount option (and possibly a config
>> option to forcibly enable the mount option). I personally have 5 or 6
>> different custom scripts that depend on being able to unmount and
>> remount devpts without losing access to the TTYs therein. Eventually
>> I will need to port those over to use "mount --move", but it would be
>> bad to have a random kernel upgrade just break my imaging/cloning
> An interesting point. What should the semantics be. If we unmount /dev/pts
> and people still have ptys open. -EBUSY? Except for lazy unmounts?
Well, even if it's unmounted you can still access your pty with
/dev/tty. As it stands right now it's possible to "umount /dev/pts"
from an SSH login and still have a mostly-functional system. The only
failure will be when somebody needs a pseudo-TTY and you have devpts
unmounted and UNIX98 ptys turned off.
So for the legacy case, the behavior should be exactly as it is now.
In the CONFIG_DEVPTY_FORCE_PERMOUNT/"permount"-option case, I agree
that you could easily go either way.
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