diff --git a/servers/vfs/dmap.c b/servers/vfs/dmap.c
index 54235e29d..ed83553e2 100644
--- a/servers/vfs/dmap.c
+++ b/servers/vfs/dmap.c
@@ -87,9 +87,10 @@ int flags;			/* device flags */
  * NONE, we're supposed to unmap it.
  */
 
-  int slot;
+  int slot, s;
   size_t len;
   struct dmap *dp;
+  struct fproc *rfp;
 
   /* Get pointer to device entry in the dmap table. */
   if (major < 0 || major >= NR_DEVICES) return(ENODEV);
@@ -105,12 +106,12 @@ int flags;			/* device flags */
   }
 
   /* Check process number of new driver if it was alive before mapping */
-  if (! (flags & DRV_FORCED)) {
-	struct fproc *rfp;
-
-	if (isokendpt(proc_nr_e, &slot) != OK)
+  s = isokendpt(proc_nr_e, &slot);
+  if (s != OK) {
+	/* This is not a problem only when we force this driver mapping */
+	if (! (flags & DRV_FORCED))
 		return(EINVAL);
-
+  } else {
 	rfp = &fproc[slot];
 	rfp->fp_flags |= FP_SYS_PROC;	/* Process is a driver */
   }
diff --git a/servers/vfs/main.c b/servers/vfs/main.c
index 97883d3f1..863691890 100644
--- a/servers/vfs/main.c
+++ b/servers/vfs/main.c
@@ -147,31 +147,36 @@ static void handle_work(void *(*func)(void *arg))
 
   proc_e = m_in.m_source;
 
-  if ((vmp = find_vmnt(proc_e)) != NULL) {
-	/* A call back or dev result from an FS endpoint */
-
-	/* Set call back flag. We assume that an FS does only one call back
-	 * at a time */
-	vmp->m_flags |= VMNT_CALLBACK;
-
-	/* When an FS point has to make a call back in order to mount, force
-	 * its device to a "none device" so block reads/writes will be handled
-	 * by ROOT_FS_E.
-	 */
-	if (vmp->m_flags & VMNT_MOUNTING)
-		vmp->m_flags |= VMNT_FORCEROOTBSF;
-
+  if (fp->fp_flags & FP_SYS_PROC) {
 	if (worker_available() == 0) {
-		/* No worker threads available to handle call */
-		if (deadlock_resolving) {
-			/* Already trying to resolve a deadlock, can't
-			 * handle more, sorry */
-			vmp->m_flags &= ~VMNT_CALLBACK;
-			reply(proc_e, EAGAIN);
+		if (!deadlock_resolving) {
+			if ((vmp = find_vmnt(proc_e)) != NULL) {
+				/* A call back or dev result from an FS
+				 * endpoint. Set call back flag. Can do only
+				 * one call back at a time.
+				 */
+				if (vmp->m_flags & VMNT_CALLBACK) {
+					reply(proc_e, EAGAIN);
+					return;
+				}
+				vmp->m_flags |= VMNT_CALLBACK;
+
+				/* When an FS endpoint has to make a call back
+				 * in order to mount, force its device to a
+				 * "none device" so block reads/writes will be
+				 * handled by ROOT_FS_E.
+				 */
+				if (vmp->m_flags & VMNT_MOUNTING)
+					vmp->m_flags |= VMNT_FORCEROOTBSF;
+			}
+			deadlock_resolving = 1;
+			dl_worker_start(func);
 			return;
 		}
-		deadlock_resolving = 1;
-		dl_worker_start(func);
+		/* Already trying to resolve a deadlock, can't
+		 * handle more, sorry */
+
+		reply(proc_e, EAGAIN);
 		return;
 	}
   }
diff --git a/servers/vfs/proto.h b/servers/vfs/proto.h
index 3689c6c29..6cde7927c 100644
--- a/servers/vfs/proto.h
+++ b/servers/vfs/proto.h
@@ -62,7 +62,6 @@ struct dmap *get_dmap(endpoint_t proc_e);
 int do_mapdriver(void);
 int map_service(struct rprocpub *rpub);
 void dmap_unmap_by_endpt(int proc_nr);
-struct dmap *get_dmap(endpoint_t proc_e);
 int map_driver(const char *label, int major, endpoint_t proc_nr, int
 	dev_style, int flags);
 int map_service(struct rprocpub *rpub);