From 543bbfd1a149e9545e0d134f03954ee902476e1a Mon Sep 17 00:00:00 2001
From: alex <alex>
Date: Sat, 31 Jul 2004 14:43:41 +0000
Subject: [PATCH] b=4049 r=adilger

- fix lock inversion by removing DLM lock acquiring in mdt_obj_create()
  instead just mark request difficult explicitly
---
 lustre/include/linux/lustre_net.h |  1 +
 lustre/mds/handler.c              | 21 ++-------------------
 lustre/ptlrpc/ptlrpc_module.c     |  1 +
 lustre/ptlrpc/service.c           | 11 +++++++++++
 4 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/lustre/include/linux/lustre_net.h b/lustre/include/linux/lustre_net.h
index 4890358..03d9ab3 100644
--- a/lustre/include/linux/lustre_net.h
+++ b/lustre/include/linux/lustre_net.h
@@ -639,6 +639,7 @@ void ptlrpc_retain_replayable_request(struct ptlrpc_request *req,
 __u64 ptlrpc_next_xid(void);
 
 /* ptlrpc/service.c */
+void ptlrpc_require_repack (struct ptlrpc_request *req);
 void ptlrpc_save_lock (struct ptlrpc_request *req, 
                        struct lustre_handle *lock, int mode);
 void ptlrpc_save_llog_lock (struct ptlrpc_request *req, 
diff --git a/lustre/mds/handler.c b/lustre/mds/handler.c
index a52583b..b3057b5 100644
--- a/lustre/mds/handler.c
+++ b/lustre/mds/handler.c
@@ -1338,14 +1338,11 @@ static void reconstruct_create(struct ptlrpc_request *req)
 static int mdt_obj_create(struct ptlrpc_request *req)
 {
         struct obd_device *obd = req->rq_export->exp_obd;
-        struct ldlm_res_id res_id = { .name = {0} };
         struct mds_obd *mds = &obd->u.mds;
         struct ost_body *body, *repbody;
         char fidname[LL_FID_NAMELEN];
         struct inode *parent_inode;
-        struct lustre_handle lockh;
         struct lvfs_run_ctxt saved;
-        ldlm_policy_data_t policy;
         struct dentry *new = NULL;
         struct dentry_params dp;
         int mealen, flags = 0, rc, size = sizeof(*repbody), cleanup_phase = 0;
@@ -1465,18 +1462,6 @@ repeat:
                         GOTO(cleanup, rc);
                 }
                         
-                /* this lock should be taken to serialize MDS modifications
-                 * in failure case */
-                res_id.name[0] = new->d_inode->i_ino;
-                res_id.name[1] = new->d_inode->i_generation;
-                policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
-                rc = ldlm_cli_enqueue(NULL, NULL, obd->obd_namespace,
-                                res_id, LDLM_IBITS, &policy,
-                                LCK_EX, &flags, mds_blocking_ast,
-                                ldlm_completion_ast, NULL, NULL,
-                                NULL, 0, NULL, &lockh);
-                if (rc != ELDLM_OK)
-                        GOTO(cleanup, rc);
                 cleanup_phase = 2; /* valid lockh */
 
                 CDEBUG(D_OTHER, "created dirobj: %lu/%lu mode %o\n",
@@ -1515,11 +1500,9 @@ repeat:
 
 cleanup:
         switch (cleanup_phase) {
-        case 2: /* valid lockh */
+        case 2: /* object has been created, but we'll may want to replay it later */
                 if (rc == 0)
-                        ptlrpc_save_lock(req, &lockh, LCK_EX);
-                else
-                        ldlm_lock_decref(&lockh, LCK_EX);
+                        ptlrpc_require_repack(req);
         case 1: /* transaction */
                 rc = mds_finish_transno(mds, parent_inode, handle, req, rc, 0);
         }
diff --git a/lustre/ptlrpc/ptlrpc_module.c b/lustre/ptlrpc/ptlrpc_module.c
index 9e3a0c7..cfd1ad2 100644
--- a/lustre/ptlrpc/ptlrpc_module.c
+++ b/lustre/ptlrpc/ptlrpc_module.c
@@ -133,6 +133,7 @@ EXPORT_SYMBOL(ptlrpc_fail_import);
 EXPORT_SYMBOL(ptlrpc_disconnect_import);
 
 /* service.c */
+EXPORT_SYMBOL(ptlrpc_require_repack);
 EXPORT_SYMBOL(ptlrpc_save_lock);
 EXPORT_SYMBOL(ptlrpc_save_llog_lock);
 EXPORT_SYMBOL(ptlrpc_schedule_difficult_reply);
diff --git a/lustre/ptlrpc/service.c b/lustre/ptlrpc/service.c
index 692c929..3cea525 100644
--- a/lustre/ptlrpc/service.c
+++ b/lustre/ptlrpc/service.c
@@ -129,6 +129,14 @@ ptlrpc_save_llog_lock (struct ptlrpc_request *req,
 }
 
 void
+ptlrpc_require_repack(struct ptlrpc_request *req)
+{
+        struct ptlrpc_reply_state *rs = req->rq_reply_state;
+        LASSERT (rs != NULL);
+        rs->rs_difficult = 1;
+}
+
+void
 ptlrpc_save_lock (struct ptlrpc_request *req, 
                   struct lustre_handle *lock, int mode)
 {
@@ -577,12 +585,15 @@ ptlrpc_server_handle_reply (struct ptlrpc_service *svc)
         if (nlocks == 0 && !been_handled) {
                 /* If we see this, we should already have seen the warning
                  * in mds_steal_ack_locks()  */
+#if 0   
+                /* CMD may ask to save request with no DLM locks -bzzz */
                 CWARN("All locks stolen from rs %p x"LPD64".t"LPD64
                       " o%d NID %s\n",
                       rs, 
                       rs->rs_xid, rs->rs_transno,
                       rs->rs_msg.opc, 
                       ptlrpc_peernid2str(&exp->exp_connection->c_peer, str));
+#endif
         }
 
         if ((!been_handled && rs->rs_on_net) || 
-- 
1.8.3.1