Revert "DAOS-14969 container: retry IV might cause deadlock (#13632)"

This reverts commit 1946ef3.

Conflicts:
  src/engine/server_iv.c

Required-githooks: true

src/cart/crt_iv.c

@@ -3509,8 +3509,8 @@ crt_iv_update_internal(crt_iv_namespace_t ivns, uint32_t class_id,
 
 		D_GOTO(exit, rc);
 	} else {
-		DL_CDEBUG(rc == -DER_NONEXIST || rc == -DER_NOTLEADER || rc == -DER_BUSY,
-			  DLOG_INFO, DLOG_ERR, rc, "ivo_on_update failed");
+		DL_CDEBUG(rc == -DER_NONEXIST || rc == -DER_NOTLEADER, DLOG_INFO, DLOG_ERR, rc,
+			  "ivo_on_update failed");
 
 		update_comp_cb(ivns, class_id, iv_key, NULL,
 			       iv_value, rc, cb_arg);

src/container/oid_iv.c

@@ -31,7 +31,6 @@ struct oid_iv_entry {
 	struct oid_iv_range	rg;
 	/** protect the entry */
 	ABT_mutex		lock;
-	void			*current_req;
 };
 
 /** Priv data in the iv layer */
@@ -131,14 +130,7 @@ oid_iv_ent_update(struct ds_iv_entry *ns_entry, struct ds_iv_key *iv_key,
 	D_ASSERT(priv != NULL);
 
 	entry = ns_entry->iv_value.sg_iovs[0].iov_buf;
-	rc = ABT_mutex_trylock(entry->lock);
-	/* For retry requests, from _iv_op(), the lock may not be released
-	 * in some cases.
-	 */
-	if (rc == ABT_ERR_MUTEX_LOCKED && entry->current_req != src)
-		return -DER_BUSY;
-
-	entry->current_req = src;
+	ABT_mutex_lock(entry->lock);
 	avail = &entry->rg;
 
 	oids = src->sg_iovs[0].iov_buf;

src/engine/server_iv.c

@@ -1,5 +1,5 @@
 /**
- * (C) Copyright 2017-2024 Intel Corporation.
+ * (C) Copyright 2017-2023 Intel Corporation.
  *
  * SPDX-License-Identifier: BSD-2-Clause-Patent
  */
@@ -1067,7 +1067,7 @@ _iv_op(struct ds_iv_ns *ns, struct ds_iv_key *key, d_sg_list_t *value,
 retry:
 	rc = iv_op_internal(ns, key, value, sync, shortcut, opc);
 	if (retry && !ns->iv_stop &&
-	    (daos_rpc_retryable_rc(rc) || rc == -DER_NOTLEADER || rc == -DER_BUSY)) {
+	    (daos_rpc_retryable_rc(rc) || rc == -DER_NOTLEADER)) {
 		if (rc == -DER_GRPVER && engine_in_check()) {
 			/*
 			 * Under check mode, the pool shard on peer rank/target does
@@ -1094,7 +1094,7 @@ _iv_op(struct ds_iv_ns *ns, struct ds_iv_key *key, d_sg_list_t *value,
 		 * but in-flight fetch request return IVCB_FORWARD, then queued RPC will
 		 * reply IVCB_FORWARD.
 		 */
-		D_INFO("ns %u retry for class %d opc %d rank %u/%u: " DF_RC "\n", ns->iv_ns_id,
+		D_WARN("ns %u retry for class %d opc %d rank %u/%u: " DF_RC "\n", ns->iv_ns_id,
 		       key->class_id, opc, key->rank, ns->iv_master_rank, DP_RC(rc));
 		/* sleep 1sec and retry */
 		dss_sleep(1000);