From: Patrick Farrell <pfarrell@whamcloud.com>
Date: Tue, 16 Jul 2019 19:26:43 +0000 (-0400)
Subject: LU-12559 ptlrpc: Hold imp lock for idle reconnect
X-Git-Tag: 2.12.90~130
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=e9472c54ac820c3a0db2318a6ef894c3971e6e0b;ds=sidebyside

LU-12559 ptlrpc: Hold imp lock for idle reconnect

Idle reconnect sets import state to IMP_NEW, then releases
the import lock before calling ptlrpc_connect_import.  This
creates a gap where an import in IMP_NEW state is exposed,
which can cause new requests to fail with EIO.

Hold the lock across the call so as not to expose imports
in this state.

Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Change-Id: I9f8509d11c4d5a8917a313349534d98b964cd588
Reviewed-on: https://review.whamcloud.com/35530
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Wang Shilong <wshilong@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
---

diff --git a/lustre/include/lustre_net.h b/lustre/include/lustre_net.h
index 52e3ddf..fd1589a 100644
--- a/lustre/include/lustre_net.h
+++ b/lustre/include/lustre_net.h
@@ -2279,6 +2279,7 @@ void ptlrpc_hr_fini(void);
  * @{
  */
 int ptlrpc_connect_import(struct obd_import *imp);
+int ptlrpc_connect_import_locked(struct obd_import *imp);
 int ptlrpc_init_import(struct obd_import *imp);
 int ptlrpc_disconnect_import(struct obd_import *imp, int noclose);
 int ptlrpc_disconnect_and_idle_import(struct obd_import *imp);
diff --git a/lustre/ptlrpc/client.c b/lustre/ptlrpc/client.c
index 300ec30..48ade0f 100644
--- a/lustre/ptlrpc/client.c
+++ b/lustre/ptlrpc/client.c
@@ -894,7 +894,6 @@ ptlrpc_request_alloc_internal(struct obd_import *imp,
 			      const struct req_format *format)
 {
 	struct ptlrpc_request *request;
-	int connect = 0;
 
 	request = __ptlrpc_request_alloc(imp, pool);
 	if (!request)
@@ -915,17 +914,17 @@ ptlrpc_request_alloc_internal(struct obd_import *imp,
 		if (imp->imp_state == LUSTRE_IMP_IDLE) {
 			imp->imp_generation++;
 			imp->imp_initiated_at = imp->imp_generation;
-			imp->imp_state =  LUSTRE_IMP_NEW;
-			connect = 1;
-		}
-		spin_unlock(&imp->imp_lock);
-		if (connect) {
-			rc = ptlrpc_connect_import(imp);
+			imp->imp_state = LUSTRE_IMP_NEW;
+
+			/* connect_import_locked releases imp_lock */
+			rc = ptlrpc_connect_import_locked(imp);
 			if (rc < 0) {
 				ptlrpc_request_free(request);
 				return NULL;
 			}
 			ptlrpc_pinger_add_import(imp);
+		} else {
+			spin_unlock(&imp->imp_lock);
 		}
 	}
 
diff --git a/lustre/ptlrpc/import.c b/lustre/ptlrpc/import.c
index cc963df..b7ce038 100644
--- a/lustre/ptlrpc/import.c
+++ b/lustre/ptlrpc/import.c
@@ -658,13 +658,22 @@ static int ptlrpc_first_transno(struct obd_import *imp, __u64 *transno)
 	return 0;
 }
 
+int ptlrpc_connect_import(struct obd_import *imp)
+{
+	spin_lock(&imp->imp_lock);
+	return ptlrpc_connect_import_locked(imp);
+}
+
 /**
  * Attempt to (re)connect import \a imp. This includes all preparations,
  * initializing CONNECT RPC request and passing it to ptlrpcd for
  * actual sending.
+ *
+ * Assumes imp->imp_lock is held, and releases it.
+ *
  * Returns 0 on success or error code.
  */
-int ptlrpc_connect_import(struct obd_import *imp)
+int ptlrpc_connect_import_locked(struct obd_import *imp)
 {
 	struct obd_device *obd = imp->imp_obd;
 	int initial_connect = 0;
@@ -682,7 +691,8 @@ int ptlrpc_connect_import(struct obd_import *imp)
 	int rc;
 	ENTRY;
 
-	spin_lock(&imp->imp_lock);
+	assert_spin_locked(&imp->imp_lock);
+
 	if (imp->imp_state == LUSTRE_IMP_CLOSED) {
 		spin_unlock(&imp->imp_lock);
 		CERROR("can't connect to a closed import\n");
@@ -1770,12 +1780,13 @@ static int ptlrpc_disconnect_idle_interpret(const struct lu_env *env,
 			connect = 1;
 		}
 	}
-	spin_unlock(&imp->imp_lock);
 
 	if (connect) {
-		rc = ptlrpc_connect_import(imp);
+		rc = ptlrpc_connect_import_locked(imp);
 		if (rc >= 0)
 			ptlrpc_pinger_add_import(imp);
+	} else {
+		spin_unlock(&imp->imp_lock);
 	}
 
 	return 0;