[DRBD-cvs] svn commit by lars - r2289 - branches/drbd-0.7/drbd - don't look at the socket without holding the appropriat

[drbd-cvs at lists.linbit.com]

Author: lars
Date: 2006-07-20 14:12:42 +0200 (Thu, 20 Jul 2006)
New Revision: 2289

Modified:
   branches/drbd-0.7/drbd/drbd_int.h
   branches/drbd-0.7/drbd/drbd_main.c
Log:

don't look at the socket without holding the appropriate mutex



Modified: branches/drbd-0.7/drbd/drbd_int.h
===================================================================
--- branches/drbd-0.7/drbd/drbd_int.h	2006-07-20 10:57:56 UTC (rev 2288)
+++ branches/drbd-0.7/drbd/drbd_int.h	2006-07-20 12:12:42 UTC (rev 2289)
@@ -832,7 +832,9 @@
 extern int _drbd_send_cmd(drbd_dev *mdev, struct socket *sock,
 			  Drbd_Packet_Cmd cmd, Drbd_Header *h,
 			  size_t size, unsigned msg_flags);
-extern int drbd_send_cmd(drbd_dev *mdev, struct socket *sock,
+#define USE_DATA_SOCKET 1
+#define USE_META_SOCKET 0
+extern int drbd_send_cmd(drbd_dev *mdev, int use_data_socket,
 			  Drbd_Packet_Cmd cmd, Drbd_Header *h, size_t size);
 extern int drbd_send_sync_param(drbd_dev *mdev, struct syncer_config *sc);
 extern int drbd_send_b_ack(drbd_dev *mdev, u32 barrier_nr,
@@ -1271,19 +1273,19 @@
 static inline int drbd_send_short_cmd(drbd_dev *mdev, Drbd_Packet_Cmd cmd)
 {
 	Drbd_Header h;
-	return drbd_send_cmd(mdev,mdev->data.socket,cmd,&h,sizeof(h));
+	return drbd_send_cmd(mdev,USE_DATA_SOCKET,cmd,&h,sizeof(h));
 }
 
 static inline int drbd_send_ping(drbd_dev *mdev)
 {
 	Drbd_Header h;
-	return drbd_send_cmd(mdev,mdev->meta.socket,Ping,&h,sizeof(h));
+	return drbd_send_cmd(mdev,USE_META_SOCKET,Ping,&h,sizeof(h));
 }
 
 static inline int drbd_send_ping_ack(drbd_dev *mdev)
 {
 	Drbd_Header h;
-	return drbd_send_cmd(mdev,mdev->meta.socket,PingAck,&h,sizeof(h));
+	return drbd_send_cmd(mdev,USE_META_SOCKET,PingAck,&h,sizeof(h));
 }
 
 static inline void drbd_thread_stop(struct Drbd_thread *thi)

Modified: branches/drbd-0.7/drbd/drbd_main.c
===================================================================
--- branches/drbd-0.7/drbd/drbd_main.c	2006-07-20 10:57:56 UTC (rev 2288)
+++ branches/drbd-0.7/drbd/drbd_main.c	2006-07-20 12:12:42 UTC (rev 2289)
@@ -628,6 +628,7 @@
 	UNLOCK_SIGMASK(current,flags);
 }
 
+/* the appropriate socket mutex must be held already */
 int _drbd_send_cmd(drbd_dev *mdev, struct socket *sock,
 			  Drbd_Packet_Cmd cmd, Drbd_Header *h,
 			  size_t size, unsigned msg_flags)
@@ -652,32 +653,36 @@
 	return ok;
 }
 
-int drbd_send_cmd(drbd_dev *mdev, struct socket *sock,
+/* don't pass the socket. we may only look at it
+ * when we hold the appropriate socket mutex.
+ */
+int drbd_send_cmd(drbd_dev *mdev, int use_data_socket,
 		  Drbd_Packet_Cmd cmd, Drbd_Header* h, size_t size)
 {
-	int ok;
+	int ok = 0;
 	sigset_t old_blocked;
+	struct socket *sock;
 
-	if (sock == mdev->data.socket) {
+	if (use_data_socket) {
 		down(&mdev->data.mutex);
-		if (sock != mdev->data.socket) {
-			/* verify drbd_disconnect: drbd_free_sock may free this
-			 * socket while we have been waiting in down.
-			 */
-			up(&mdev->data.mutex);
-			return 0; /* not ok */
-		}
 		spin_lock(&mdev->send_task_lock);
 		mdev->send_task=current;
 		spin_unlock(&mdev->send_task_lock);
-	} else
+		sock = mdev->data.socket;
+	} else {
 		down(&mdev->meta.mutex);
+		sock = mdev->meta.socket;
+	}
 
-	old_blocked = drbd_block_all_signals();
-	ok = _drbd_send_cmd(mdev,sock,cmd,h,size,0);
-	restore_old_sigset(old_blocked);
+	/* drbd_disconnect() could have called drbd_free_sock()
+	 * while we were waiting in down()... */
+	if (likely(sock != NULL)) {
+		old_blocked = drbd_block_all_signals();
+		ok = _drbd_send_cmd(mdev, sock, cmd, h, size, 0);
+		restore_old_sigset(old_blocked);
+	}
 
-	if (sock == mdev->data.socket) {
+	if (use_data_socket) {
 		spin_lock(&mdev->send_task_lock);
 		mdev->send_task=NULL;
 		spin_unlock(&mdev->send_task_lock);
@@ -697,7 +702,7 @@
 	p.skip      = cpu_to_be32(sc->skip);
 	p.group     = cpu_to_be32(sc->group);
 
-	ok = drbd_send_cmd(mdev,mdev->data.socket,SyncParam,(Drbd_Header*)&p,sizeof(p));
+	ok = drbd_send_cmd(mdev,USE_DATA_SOCKET,SyncParam,(Drbd_Header*)&p,sizeof(p));
 	if ( ok
 	    && (mdev->cstate == SkippedSyncS || mdev->cstate == SkippedSyncT)
 	    && !sc->skip )
@@ -739,7 +744,7 @@
 	p.flags          = cpu_to_be32(flags);
 	p.magic          = BE_DRBD_MAGIC;
 
-	ok = drbd_send_cmd(mdev,mdev->data.socket,ReportParams,(Drbd_Header*)&p,sizeof(p));
+	ok = drbd_send_cmd(mdev,USE_DATA_SOCKET,ReportParams,(Drbd_Header*)&p,sizeof(p));
 	if (have_disk) dec_local(mdev);
 	return ok;
 }
@@ -827,7 +832,7 @@
 	p.barrier  = barrier_nr;
 	p.set_size = cpu_to_be32(set_size);
 
-	ok = drbd_send_cmd(mdev,mdev->meta.socket,BarrierAck,(Drbd_Header*)&p,sizeof(p));
+	ok = drbd_send_cmd(mdev,USE_META_SOCKET,BarrierAck,(Drbd_Header*)&p,sizeof(p));
 	return ok;
 }
 
@@ -842,7 +847,7 @@
 	p.blksize  = cpu_to_be32(drbd_ee_get_size(e));
 
 	if (!mdev->meta.socket || mdev->cstate < Connected) return FALSE;
-	ok = drbd_send_cmd(mdev,mdev->meta.socket,cmd,(Drbd_Header*)&p,sizeof(p));
+	ok = drbd_send_cmd(mdev,USE_META_SOCKET,cmd,(Drbd_Header*)&p,sizeof(p));
 	return ok;
 }
 
@@ -856,7 +861,7 @@
 	p.block_id = block_id;
 	p.blksize  = cpu_to_be32(size);
 
-	ok = drbd_send_cmd(mdev,mdev->data.socket,cmd,(Drbd_Header*)&p,sizeof(p));
+	ok = drbd_send_cmd(mdev,USE_DATA_SOCKET,cmd,(Drbd_Header*)&p,sizeof(p));
 	return ok;
 }
 
@@ -1151,7 +1156,7 @@
 */
 
 /*
- * you should have down()ed the appropriate [m]sock_mutex elsewhere!
+ * you must have down()ed the appropriate [m]sock_mutex elsewhere!
  */
 int drbd_send(drbd_dev *mdev, struct socket *sock,
 	      void* buf, size_t size, unsigned msg_flags)