• David Howells's avatar
    afs: Lay the groundwork for supporting network namespaces · f044c884
    David Howells authored
    Lay the groundwork for supporting network namespaces (netns) to the AFS
    filesystem by moving various global features to a network-namespace struct
    (afs_net) and providing an instance of this as a temporary global variable
    that everything uses via accessor functions for the moment.
    The following changes have been made:
     (1) Store the netns in the superblock info.  This will be obtained from
         the mounter's nsproxy on a manual mount and inherited from the parent
         superblock on an automount.
     (2) The cell list is made per-netns.  It can be viewed through
         /proc/net/afs/cells and also be modified by writing commands to that
     (3) The local workstation cell is set per-ns in /proc/net/afs/rootcell.
         This is unset by default.
     (4) The 'rootcell' module parameter, which sets a cell and VL server list
         modifies the init net namespace, thereby allowing an AFS root fs to be
         theoretically used.
     (5) The volume location lists and the file lock manager are made
     (6) The AF_RXRPC socket and associated I/O bits are made per-ns.
    The various workqueues remain global for the moment.
    Changes still to be made:
     (1) /proc/fs/afs/ should be moved to /proc/net/afs/ and a symlink emplaced
         from the old name.
     (2) A per-netns subsys needs to be registered for AFS into which it can
         store its per-netns data.
     (3) Rather than the AF_RXRPC socket being opened on module init, it needs
         to be opened on the creation of a superblock in that netns.
     (4) The socket needs to be closed when the last superblock using it is
         destroyed and all outstanding client calls on it have been completed.
         This prevents a reference loop on the namespace.
     (5) It is possible that several namespaces will want to use AFS, in which
         case each one will need its own UDP port.  These can either be set
         through /proc/net/afs/cm_port or the kernel can pick one at random.
         The init_ns gets 7001 by default.
    Other issues that need resolving:
     (1) The DNS keyring needs net-namespacing.
     (2) Where do upcalls go (eg. DNS request-key upcall)?
     (3) Need something like open_socket_in_file_ns() syscall so that AFS
         command line tools attempting to operate on an AFS file/volume have
         their RPC calls go to the right place.
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
volume.c 9.8 KB