• Joel Becker's avatar
    ocfs2: Negotiate locking protocol versions. · d24fbcda
    Joel Becker authored
    Currently, when ocfs2 nodes connect via TCP, they advertise their
    compatibility level.  If the versions do not match, two nodes cannot speak
    to each other and they disconnect. As a result, this provides no forward or
    backwards compatibility.
    This patch implements a simple protocol negotiation at the dlm level by
    introducing a major/minor version number scheme for entities that
    communicate.  Specifically, o2dlm has a major/minor version for interaction
    with o2dlm on other nodes, and ocfs2 itself has a major/minor version for
    interacting with the filesystem on other nodes.
    This will allow rolling upgrades of ocfs2 clusters when changes to the
    locking or network protocols can be done in a backwards compatible manner.
    In those cases, only the minor number is changed and the negotatied protocol
    minor is returned from dlm join. In the far less likely event that a
    required protocol change makes backwards compatibility impossible, we simply
    bump the major number.
    Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
    Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
ocfs2_lockingver.h 907 Bytes