From: Chris Snook <csnook@redhat.com>
Subject: [RHEL 5.1 PATCH] BZ 230171 fix dasd reservations
Date: Tue, 20 Mar 2007 00:36:28 -0400
Bugzilla: 230171
Message-Id: <45FF64CC.7060306@redhat.com>
Changelog: [s390] fix dasd reservations


Hey folks --

	The DASD reservation feature is currently broken because it bails 
	out on a non-fatal error which will always be returned if another guest has 
previously reserved it.  The attached patch, written and tested by IBM, 
enables retries, which are always successful unless the device is really 
already reserved by another guest.

	Fixes BZ 230171.  Please ack.

	-- Chris

diff -Naurp linux-2.6.18.s390x/drivers/s390/block/dasd.c linux-2.6.18.s390x-new/drivers/s390/block/dasd.c
--- linux-2.6.18.s390x/drivers/s390/block/dasd.c	2006-09-20 05:42:06.000000000 +0200
+++ linux-2.6.18.s390x-new/drivers/s390/block/dasd.c	2007-01-31 17:23:38.000000000 +0100
@@ -1023,8 +1023,6 @@ dasd_int_handler(struct ccw_device *cdev
 		 irb->scsw.cstat == 0 &&
 		 !irb->esw.esw0.erw.cons)
 		era = dasd_era_none;
-	else if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags))
- 	        era = dasd_era_fatal; /* don't recover this request */
 	else if (irb->esw.esw0.erw.cons)
 		era = device->discipline->examine_error(cqr, irb);
 	else
@@ -1128,7 +1126,9 @@ restart:
 				cqr->status = DASD_CQR_FAILED;
 				cqr->stopclk = get_clock();
 			} else {
-				if (cqr->irb.esw.esw0.erw.cons) {
+				if (cqr->irb.esw.esw0.erw.cons &&
+				    test_bit(DASD_CQR_FLAGS_USE_ERP,
+					     &cqr->flags)) {
 					erp_fn = device->discipline->
 						erp_action(cqr);
 					erp_fn(cqr);
diff -Naurp linux-2.6.18.s390x/drivers/s390/block/dasd_eckd.c linux-2.6.18.s390x-new/drivers/s390/block/dasd_eckd.c
--- linux-2.6.18.s390x/drivers/s390/block/dasd_eckd.c	2006-09-20 05:42:06.000000000 +0200
+++ linux-2.6.18.s390x-new/drivers/s390/block/dasd_eckd.c	2007-01-31 17:24:21.000000000 +0100
@@ -1380,7 +1380,7 @@ dasd_eckd_release(struct dasd_device *de
 	cqr->device = device;
 	clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 	set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
-	cqr->retries = 0;
+	cqr->retries = 2;	/* set retry counter to enable basic ERP */
 	cqr->expires = 2 * HZ;
 	cqr->buildclk = get_clock();
 	cqr->status = DASD_CQR_FILLED;
@@ -1420,7 +1420,7 @@ dasd_eckd_reserve(struct dasd_device *de
 	cqr->device = device;
 	clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 	set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
-	cqr->retries = 0;
+	cqr->retries = 2;	/* set retry counter to enable basic ERP */
 	cqr->expires = 2 * HZ;
 	cqr->buildclk = get_clock();
 	cqr->status = DASD_CQR_FILLED;
@@ -1459,7 +1459,7 @@ dasd_eckd_steal_lock(struct dasd_device 
 	cqr->device = device;
 	clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 	set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
-	cqr->retries = 0;
+	cqr->retries = 2;	/* set retry counter to enable basic ERP */
 	cqr->expires = 2 * HZ;
 	cqr->buildclk = get_clock();
 	cqr->status = DASD_CQR_FILLED;