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Commit 294e7e45 authored by tsutomu.owa@toshiba.co.jp's avatar tsutomu.owa@toshiba.co.jp Committed by David Teigland
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DLM: fix conversion deadlock when DLM_LKF_NODLCKWT flag is set 



When the DLM_LKF_NODLCKWT flag was set, even if conversion deadlock
was detected, the caller of can_be_granted() was unknown.
We change the behavior of can_be_granted() and change it to detect
conversion deadlock regardless of whether the DLM_LKF_NODLCKWT flag
is set or not. And depending on whether the DLM_LKF_NODLCKWT flag
is set or not, we change the behavior at the caller of can_be_granted().

This fix has no effect except when using DLM_LKF_NODLCKWT flag.
Currently, ocfs2 uses the DLM_LKF_NODLCKWT flag and does not expect a
cancel operation from conversion deadlock when calling dlm_lock().
ocfs2 is implemented to perform a cancel operation by requesting
BASTs (callback).

Signed-off-by: default avatarTadashi Miyauchi <miyauchi@toshiba-tops.co.jp>
Signed-off-by: default avatarTsutomu Owa <tsutomu.owa@toshiba.co.jp>
Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent 173a31fe

fs/dlm/lock.c

+23 −19
Original line number Original line Diff line number Diff line
@@ -2465,15 +2465,13 @@ static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now, 
		if (lkb->lkb_exflags & DLM_LKF_CONVDEADLK) {

		if (lkb->lkb_exflags & DLM_LKF_CONVDEADLK) {

			lkb->lkb_grmode = DLM_LOCK_NL;

			lkb->lkb_grmode = DLM_LOCK_NL;

			lkb->lkb_sbflags |= DLM_SBF_DEMOTED;

			lkb->lkb_sbflags |= DLM_SBF_DEMOTED;

		} else if (!(lkb->lkb_exflags & DLM_LKF_NODLCKWT)) {

		} else if (err) {

			if (err)

			*err = -EDEADLK;

			*err = -EDEADLK;

			else {

		} else {

			log_print("can_be_granted deadlock %x now %d",

			log_print("can_be_granted deadlock %x now %d",

				  lkb->lkb_id, now);

				  lkb->lkb_id, now);

			dlm_dump_rsb(r);

			dlm_dump_rsb(r);

		}

		}

		}

		goto out;

		goto out;

	}

	}
@@ -2501,13 +2499,6 @@ static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now, 
	return rv;

	return rv;

}

}





/* FIXME: I don't think that can_be_granted() can/will demote or find deadlock

   for locks pending on the convert list.  Once verified (watch for these

   log_prints), we should be able to just call _can_be_granted() and not

   bother with the demote/deadlk cases here (and there's no easy way to deal

   with a deadlk here, we'd have to generate something like grant_lock with

   the deadlk error.) */



/* Returns the highest requested mode of all blocked conversions; sets

/* Returns the highest requested mode of all blocked conversions; sets

   cw if there's a blocked conversion to DLM_LOCK_CW. */

   cw if there's a blocked conversion to DLM_LOCK_CW. */
@@ -2545,9 +2536,22 @@ static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw, 
		}

		}





		if (deadlk) {

		if (deadlk) {

			/*

			 * If DLM_LKB_NODLKWT flag is set and conversion

			 * deadlock is detected, we request blocking AST and

			 * down (or cancel) conversion.

			 */

			if (lkb->lkb_exflags & DLM_LKF_NODLCKWT) {

				if (lkb->lkb_highbast < lkb->lkb_rqmode) {

					queue_bast(r, lkb, lkb->lkb_rqmode);

					lkb->lkb_highbast = lkb->lkb_rqmode;

				}

			} else {

				log_print("WARN: pending deadlock %x node %d %s",

				log_print("WARN: pending deadlock %x node %d %s",

				  lkb->lkb_id, lkb->lkb_nodeid, r->res_name);

					  lkb->lkb_id, lkb->lkb_nodeid,

					  r->res_name);

				dlm_dump_rsb(r);

				dlm_dump_rsb(r);

			}

			continue;

			continue;

		}

		}
@@ -3123,7 +3127,7 @@ static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb) 
	   deadlock, so we leave it on the granted queue and return EDEADLK in

	   deadlock, so we leave it on the granted queue and return EDEADLK in

	   the ast for the convert. */

	   the ast for the convert. */





	if (deadlk) {

	if (deadlk && !(lkb->lkb_exflags & DLM_LKF_NODLCKWT)) {

		/* it's left on the granted queue */

		/* it's left on the granted queue */

		revert_lock(r, lkb);

		revert_lock(r, lkb);

		queue_cast(r, lkb, -EDEADLK);

		queue_cast(r, lkb, -EDEADLK);