This patchset includes the patches to cleanup get_node() I had sent earlier, with the Sign-off added. No other changes were made to those patches since I last sent.
--- Enable multiple mounts of devpts filesystem so each container can allocate ptys independently. User interface: Since supporting multiple mounts of devpts can break user-space, this feature is enabled only under a new mount option (-o newinstance). If this option is never specified, this patchset should not change any behavior. i.e existing single-namespace semantics are preserved across any remounts of /dev/pts (as long as none of them use the new option). So old startup scripts should continue to work. If the '-o newinstance' option is specified, then a new 'private' mount of devpts is created. Ptys in this private instance are independent of ptys created in other devpts instances. For this to be fully functional, /dev/ptmx must be a bind-mount of '/dev/pts/ptmx' i.e mount -t devpts -o newinstance lxcpts /dev/pts mount -o bind /dev/pts/ptmx /dev/ptmx See [PATCH 11/11] for more details on usage. Implementation notes: 1. To enable multiple mounts of /dev/pts, (most) devpts interfaces need to know which instance of devpts is being accessed. This patchset uses the 'struct inode' or 'struct tty_struct' of the device being accessed to identify the appropriate devpts instance. Hence the need for the /dev/pts/ptmx bind-mount. 2. See comments in get_sb_ref() in fs/super.c (could not find existing interfaces that accomplish it) Or is there a better way ? 3. Mount options must be parsed twice during mount (once to determine the mode of mount (single/multi-instance) and once to actually save the options. There does not seem to be an easy way to parse once and reuse (See 'safe_process_mount_opts()' in PATCH 11/11) [PATCH 1/11]: Move tty lookup/reopen to tty_open [PATCH 2/11]: Add an instance parameter to devpts interfaces [PATCH 3/11]: Simplify devpts_get_tty() [PATCH 4/11]: Simplify devpts_pty_new() [PATCH 5/11]: Simplify devpts_pty_kill [PATCH 6/11]: Remove devpts_root global [PATCH 7/11]: Per-mount allocated_ptys [PATCH 8/11]: Per-mount 'config' object [PATCH 9/11]: Extract option parsing to new function [PATCH 10/11]: Ability to internally create ptmx [PATCH 11/11]: Enable multiple instances of devpts Changelog [v3]: - Port to 2008-08-28 ttydev tree - Rename new mount options to 'ptmxmode' and 'newinstance'. - [Alan Cox] Use tty driver data to identify devpts (this is used to cleanup get_node() in devpts_pty_kill()). - [H. Peter Anvin] get_node() cleanup in devpts (which was enabled by the inode/tty parameter to devpts interfaces) - Bugfix in multi-mount mode (see Patch 11/11). - Executed pty tests in LTP (in both single-instance and multi-instance mode) - Should be bisect-safe :-) Changelog [v2]: - New mount option '-o newmnt' added (patch 8/8) - Support both single-mount and multi-mount semantics (patch 8/8) - Automatically create ptmx node when devpts is mounted (patch 7/8) - Extract option parsing code to new function (patch 6/8) - Make 'config' params per-mount variables (patch 5/8) - Slightly re-ordered existing patches in set (patches 1/8, 2/8) TODO: - Do we need a '-o ptmxuid' and '-o ptmxgid' options as well ? - Add a config option to enable multiple-mounts of devpts. - (Sometime in future) Remove even initial kernel mount of devpts - Any other good test suites to test this (besides LTP, sshd). _______________________________________________ Containers mailing list [EMAIL PROTECTED] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list Devel@openvz.org https://openvz.org/mailman/listinfo/devel