staging/lustre/mdc: layout lock rpc must not take rpc_lock

When a client issue an RPC to get a layout lock, it
must not hold rpc_lock because in case of a restore
the rpc can be blocking for a long time

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3200
Lustre-change: http://review.whamcloud.com/6115Signed-off-by: NJC Lafoucriere <jacques-charles.lafoucriere@cea.fr>
Reviewed-by: NJinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: NJohann Lombardi <johann.lombardi@intel.com>
Signed-off-by: NPeng Tao <tao.peng@emc.com>
Signed-off-by: NAndreas Dilger <andreas.dilger@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/lustre_mdc.h

@@ -86,7 +86,8 @@ static inline void mdc_get_rpc_lock(struct mdc_rpc_lock *lck,
 {
 	ENTRY;
 
-	if (it != NULL && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP))
+	if (it != NULL && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
+			   it->it_op == IT_LAYOUT))
 		return;
 
 	/* This would normally block until the existing request finishes.
@@ -123,7 +124,8 @@ static inline void mdc_get_rpc_lock(struct mdc_rpc_lock *lck,
 static inline void mdc_put_rpc_lock(struct mdc_rpc_lock *lck,
 				    struct lookup_intent *it)
 {
-	if (it != NULL && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP))
+	if (it != NULL && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
+			   it->it_op == IT_LAYOUT))
 		goto out;
 
 	if (lck->rpcl_it == MDC_FAKE_RPCL_IT) { /* OBD_FAIL_MDC_RPCS_SEM */

drivers/staging/lustre/lustre/mdc/mdc_locks.c

@@ -884,7 +884,7 @@ static int mdc_finish_intent_lock(struct obd_export *exp,
 	struct mdt_body *mdt_body;
 	struct ldlm_lock *lock;
 	int rc;
-
+	ENTRY;
 
 	LASSERT(request != NULL);
 	LASSERT(request != LP_POISON);