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    GFS2: Don't enforce min hold time when two demotes occur in rapid succession · 7b5e3d5f
    Steven Whitehouse 提交于
    Due to the design of the VFS, it is quite usual for operations on GFS2
    to consist of a lookup (requiring a shared lock) followed by an
    operation requiring an exclusive lock. If a remote node has cached an
    exclusive lock, then it will receive two demote events in rapid succession
    firstly for a shared lock and then to unlocked. The existing min hold time
    code was triggering in this case, even if the node was otherwise idle
    since the state change time was being updated by the initial demote.
    
    This patch introduces logic to skip the min hold timer in the case that
    a "double demote" of this kind has occurred. The min hold timer will
    still be used in all other cases.
    
    A new glock flag is introduced which is used to keep track of whether
    there have been any newly queued holders since the last glock state
    change. The min hold time is only applied if the flag is set.
    Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
    Tested-by: NAbhijith Das <adas@redhat.com>
    7b5e3d5f
trace_gfs2.h 10.7 KB