• Mark Fasheh's avatar
    ocfs2: Remove i_generation from inode lock names · 24c19ef4
    Mark Fasheh authored
    OCFS2 puts inode meta data in the "lock value block" provided by the DLM.
    Typically, i_generation is encoded in the lock name so that a deleted inode
    on and a new one in the same block don't share the same lvb.
    
    Unfortunately, that scheme means that the read in ocfs2_read_locked_inode()
    is potentially thrown away as soon as the meta data lock is taken - we
    cannot encode the lock name without first knowing i_generation, which
    requires a disk read.
    
    This patch encodes i_generation in the inode meta data lvb, and removes the
    value from the inode meta data lock name. This way, the read can be covered
    by a lock, and at the same time we can distinguish between an up to date and
    a stale LVB.
    
    This will help cold-cache stat(2) performance in particular.
    
    Since this patch changes the protocol version, we take the opportunity to do
    a minor re-organization of two of the LVB fields.
    Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
    24c19ef4
super.c 42.2 KB