From: Yang Sheng <ys@whamcloud.com>
Date: Thu, 14 Nov 2024 20:54:22 +0000 (-0800)
Subject: LU-18214 ldlm: change flock deadlock detection
X-Git-Tag: 2.15.7-RC1~36
X-Git-Url: https://git.whamcloud.com/gitweb?a=commitdiff_plain;h=refs%2Fchanges%2F84%2F56984%2F5;p=fs%2Flustre-release.git

LU-18214 ldlm: change flock deadlock detection

The flock deadlock detection code thought request lock
same as blocking lock is a bug. In fact, this is a case
of cycling chain. So we should treat it as a deadlock
case. Also clean up the reprocess code.

Lustre-change: https://review.whamcloud.com/56319
Lustre-commit: c2e6fa41aac428222770a4fc2826567a74a6dbc6
Signed-off-by: Yang Sheng <ys@whamcloud.com>
Change-Id: Icf0df4ac281c2cdb6cc57cb79db137d39ecef9e6
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56984
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Mikhail Pershin <mpershin@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
---

diff --git a/lustre/ldlm/ldlm_flock.c b/lustre/ldlm/ldlm_flock.c
index 745c1ea..e447378 100644
--- a/lustre/ldlm/ldlm_flock.c
+++ b/lustre/ldlm/ldlm_flock.c
@@ -212,14 +212,11 @@ ldlm_flock_deadlock(struct ldlm_lock *req, struct ldlm_lock *bl_lock)
 
 		bl_exp_conn = bl_exp->exp_connection;
 		if (bl_exp->exp_flock_hash != NULL) {
-			int found;
-
-			found = obd_nid_export_for_each(bl_exp->exp_obd,
-							&bl_exp_conn->c_peer.nid,
-							ldlm_flock_lookup_cb,
-							&cb_data);
-			if (found)
-				lock = cb_data.lock;
+			obd_nid_export_for_each(bl_exp->exp_obd,
+						&bl_exp_conn->c_peer.nid,
+						ldlm_flock_lookup_cb,
+						&cb_data);
+			lock = cb_data.lock;
 		}
 		if (lock == NULL)
 			break;
@@ -227,7 +224,6 @@ ldlm_flock_deadlock(struct ldlm_lock *req, struct ldlm_lock *bl_lock)
 		class_export_put(bl_exp);
 		bl_exp = cb_data.exp;
 
-		LASSERT(req != lock);
 		flock = &lock->l_policy_data.l_flock;
 		LASSERT(flock->owner == bl_owner);
 		bl_owner = flock->blocking_owner;
@@ -237,12 +233,16 @@ ldlm_flock_deadlock(struct ldlm_lock *req, struct ldlm_lock *bl_lock)
 		cfs_hash_put(bl_exp->exp_flock_hash, &lock->l_exp_flock_hash);
 		bl_exp = bl_exp_new;
 
+		if (req == lock) {
+			class_export_put(bl_exp);
+			return 1;
+		}
 		if (bl_exp->exp_failed)
 			break;
 
 		if (bl_owner == req_owner &&
 		    nid_same(&bl_exp_conn->c_peer.nid,
-			      &req_exp->exp_connection->c_peer.nid)) {
+			     &req_exp->exp_connection->c_peer.nid)) {
 			class_export_put(bl_exp);
 			return 1;
 		}