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       dlm_unlock - unlock a DLM lock


       #include <libdlm.h>

       int dlm_unlock(uint32_t lkid,
                      uint32_t flags, struct dlm_lksb *lksb, void *astarg);

       int dlm_unlock_wait(uint32_t lkid,
                           uint32_t flags, struct dlm_lksb *lksb);


       dlm_unlock()  unlocks  a  lock  previously acquired by dlm_lock and its

       Unless dlm_unlock_wait() is used unlocks are also asynchronous. The AST
       routine  is  called  when  the  resource  is successfully unlocked (see

       lkid Lock ID as returned in the lksb

       flags flags affecting the unlock operation:
         LKF_CANCEL       Cancel a pending lock or conversion.
                          This returns the lock to it’s previously
                          granted mode (in case of a conversion) or
                          unlocks it (in case of a waiting lock).
         LKF_IVVALBLK     Invalidate value block
         LKF_FORCEUNLOCK  Unlock the lock even if it’s waiting.

       lksb LKSB to return status and value block information.

       astarg  New  parameter  to  be  passed  to  the  completion  AST.   The
       completion  AST routine is the last completion AST routine specified in
       a dlm_lock call.  If dlm_lock_wait() was the last routine  to  issue  a
       lock, dlm_unlock_wait() must be used to release the lock. If dlm_lock()
       was the last routine to  issue  a  lock  then  either  dlm_unlock()  or
       dlm_unlock_wait() may be called.

   Return values
       0  is  returned  if  the  call  completed  successfully.  If not, -1 is
       returned and errno is set to one of the following:

       EINVAL          An invalid parameter was passed to the call (eg bad
                       lock mode or flag)
       EINPROGRESS     The lock is already being unlocked
       EBUSY           The lock is currently being locked or converted
       ENOTEMPTY       An attempt to made to unlock a parent lock that still has
                       child locks.
       ECANCEL         A lock conversion was successfully cancelled
       EUNLOCK         An unlock operation completed successfully
                       (sb_status only)
       EFAULT          The userland buffer could not be read/written by the
       If an error is returned in the AST, then lksb.sb_status is set  to  the
       one of the above numbers instead of zero.


       int status;
       struct dlm_lksb lksb;

       status = dlm_lock_wait(LKM_EXMODE,
                              0,     // Parent,
                              NULL,  // bast arg
                              NULL,  // bast routine,
                              NULL); // Range

       if (status == 0)
            dlm_unlock_wait(lksb.sb_lkid, 0, &lksb);


       libdlm(3), dlm_lock(3), dlm_open_lockspace(3), dlm_create_lockspace(3),
       dlm_close_lockspace(3), dlm_release_lockspace(3)