named pipes memory leak?

[Don Lewis]

On 10 Nov, Lukas Ertl wrote:
> Hi,
> 
> is there a known problem with named pipes in -CURRENT?
> 
> The following shell script freezes a machine in several minutes and needs
> a power cycle.  You can see the increasing memory in vmstat -z (unpcb) and
> netstat -u.  The kernel is FreeBSD 5.1-CURRENT Tue Nov 4 14:08:23 CET 2003.
> 
> ---8<---
> #/bin/sh
> 
> FIFO=/tmp/foo
> 
> for i in `jot 50000 1`; do
>    mkfifo ${FIFO}
>    echo blubb > ${FIFO} &
>    kill $!
>    rm ${FIFO}
> done
> ---8<---

If fifo_open() is interrupted, fifo_close() never gets called, and the
resources are not recovered.  I wish doing the resource recovery in
fifo_inactive() would have worked ...

Try this patch:

Index: sys/fs/fifofs/fifo_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/fs/fifofs/fifo_vnops.c,v
retrieving revision 1.89
diff -u -r1.89 fifo_vnops.c
--- sys/fs/fifofs/fifo_vnops.c	16 Jun 2003 17:17:09 -0000	1.89
+++ sys/fs/fifofs/fifo_vnops.c	10 Nov 2003 19:11:00 -0000
@@ -154,6 +154,26 @@
 }
 
 /*
+ * Dispose of fifo resources.
+ * Should be called with vnode locked
+ */
+static void
+fifo_cleanup(struct vnode *vp)
+{
+	struct fifoinfo *fip = vp->v_fifoinfo;
+
+	VI_LOCK(vp);
+	if (vp->v_usecount == 1) {
+		vp->v_fifoinfo = NULL;
+		VI_UNLOCK(vp);
+		(void)soclose(fip->fi_readsock);
+		(void)soclose(fip->fi_writesock);
+		FREE(fip, M_VNODE);
+	} else
+		VI_UNLOCK(vp);
+}
+
+/*
  * Open called to set up a new instance of a fifo or
  * to find an active instance of a fifo.
  */
@@ -249,6 +269,7 @@
 				fip->fi_readers--;
 				if (fip->fi_readers == 0)
 					socantsendmore(fip->fi_writesock);
+				fifo_cleanup(vp);
 				return (error);
 			}
 			VI_LOCK(vp);
@@ -268,6 +289,7 @@
 				fip->fi_writers--;
 				if (fip->fi_writers == 0)
 					socantrcvmore(fip->fi_readsock);
+				fifo_cleanup(vp);
 				return (error);
 			}
 			/*
@@ -554,15 +576,7 @@
 		if (fip->fi_writers == 0)
 			socantrcvmore(fip->fi_readsock);
 	}
-	VI_LOCK(vp);
-	if (vp->v_usecount == 1) {
-		vp->v_fifoinfo = NULL;
-		VI_UNLOCK(vp);
-		(void)soclose(fip->fi_readsock);
-		(void)soclose(fip->fi_writesock);
-		FREE(fip, M_VNODE);
-	} else
-		VI_UNLOCK(vp);
+	fifo_cleanup(vp);
 	VOP_UNLOCK(vp, 0, td);
 	return (0);
 }