• Mark Fasheh's avatar
    ocfs2: allocation reservations · d02f00cc
    Mark Fasheh authored
    
    
    This patch improves Ocfs2 allocation policy by allowing an inode to
    reserve a portion of the local alloc bitmap for itself. The reserved
    portion (allocation window) is advisory in that other allocation
    windows might steal it if the local alloc bitmap becomes
    full. Otherwise, the reservations are honored and guaranteed to be
    free. When the local alloc window is moved to a different portion of
    the bitmap, existing reservations are discarded.
    
    Reservation windows are represented internally by a red-black
    tree. Within that tree, each node represents the reservation window of
    one inode. An LRU of active reservations is also maintained. When new
    data is written, we allocate it from the inodes window. When all bits
    in a window are exhausted, we allocate a new one as close to the
    previous one as possible. Should we not find free space, an existing
    reservation is pulled off the LRU and cannibalized.
    Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
    d02f00cc
masklog.c 4.19 KB