• Steven Whitehouse's avatar
    GFS2: Wait for journal id on mount if not specified on mount command line · ba6e9364
    Steven Whitehouse authored
    This patch implements a wait for the journal id in the case that it has
    not been specified on the command line. This is to allow the future
    removal of the mount.gfs2 helper. The journal id would instead be
    directly communicated by gfs_controld to the file system. Here is a
    comparison of the two systems:
    
    Current:
    1. mount calls mount.gfs2
    2. mount.gfs2 connects to gfs_controld to retrieve the journal id
    3. mount.gfs2 adds the journal id to the mount command line and calls
    the mount system call
    4. gfs_controld receives the status of the mount request via a uevent
    
    Proposed:
    1. mount calls the mount system call (no mount.gfs2 helper)
    2. gfs_controld receives a uevent for a gfs2 fs which it doesn't know
    about already
    3. gfs_controld assigns a journal id to it via sysfs
    4. the mount system call then completes as normal (sending a uevent
    according to status)
    
    The advantage of the proposed system is that it is completely backward
    compatible with the current system both at the kernel and at the
    userland levels. The "first" parameter can also be set the same way,
    with the restriction that it must be set before the journal id is
    assigned.
    
    In addition, if mount becomes stuck waiting for a reply from
    gfs_controld which never arrives, then it is killable and will abort the
    mount gracefully.
    Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
    ba6e9364
incore.h 16.2 KB