DLM_UNLOCK(3)						     Library Functions Manual						     DLM_UNLOCK(3)

NAME

       dlm_unlock - unlock a DLM lock

SYNOPSIS

       #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);

DESCRIPTION

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

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

       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
		       kernel
       If an error is returned in the AST, then lksb.sb_status is set to the one of the above numbers instead of zero.

EXAMPLE

       int status;
       struct dlm_lksb lksb;

       status = dlm_lock_wait(LKM_EXMODE,
			      &lksb,
			      LKF_NOQUEUE,
			      "MyLock",
			      strlen("MyLock"),
			      0,     // Parent,
			      NULL,  // bast arg
			      NULL,  // bast routine,
			      NULL); // Range

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

SEE ALSO

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

libdlm functions						   July 5, 2007 						     DLM_UNLOCK(3)