From: semarie <semarie@openbsd.org>
Date: Tue, 12 Apr 2022 14:34:11 +0000 (+0000)
Subject: struct vnode: document the protection required for manipulating v_numoutput
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=7499e163a17c87df9f7edde994decd7bd0fdebf3;p=openbsd

struct vnode: document the protection required for manipulating v_numoutput

correct sr_rw() and sr_ccb_rw() to properly manipulate v_numoutput under splbio.

ok visa@
---

diff --git a/sys/dev/softraid.c b/sys/dev/softraid.c
index 735a61e078e..607989f7069 100644
--- a/sys/dev/softraid.c
+++ b/sys/dev/softraid.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: softraid.c,v 1.423 2022/04/06 18:59:27 naddy Exp $ */
+/* $OpenBSD: softraid.c,v 1.424 2022/04/12 14:34:11 semarie Exp $ */
 /*
  * Copyright (c) 2007, 2008, 2009 Marco Peereboom <marco@peereboom.us>
  * Copyright (c) 2008 Chris Kuethe <ckuethe@openbsd.org>
@@ -404,6 +404,7 @@ sr_rw(struct sr_softc *sc, dev_t dev, char *buf, size_t size, daddr_t blkno,
 	size_t			bufsize, dma_bufsize;
 	int			rv = 1;
 	char			*dma_buf;
+	int			s;
 
 	DNPRINTF(SR_D_MISC, "%s: sr_rw(0x%x, %p, %zu, %lld 0x%lx)\n",
 	    DEVNAME(sc), dev, buf, size, (long long)blkno, flags);
@@ -437,8 +438,11 @@ sr_rw(struct sr_softc *sc, dev_t dev, char *buf, size_t size, daddr_t blkno,
 		b.b_resid = bufsize;
 		b.b_vp = vp;
 
-		if ((b.b_flags & B_READ) == 0)
+		if ((b.b_flags & B_READ) == 0) {
+			s = splbio();
 			vp->v_numoutput++;
+			splx(s);
+		}
 
 		LIST_INIT(&b.b_dep);
 		VOP_STRATEGY(vp, &b);
@@ -1980,6 +1984,7 @@ sr_ccb_rw(struct sr_discipline *sd, int chunk, daddr_t blkno,
 {
 	struct sr_chunk		*sc = sd->sd_vol.sv_chunks[chunk];
 	struct sr_ccb		*ccb = NULL;
+	int			s;
 
 	ccb = sr_ccb_get(sd);
 	if (ccb == NULL)
@@ -2006,8 +2011,11 @@ sr_ccb_rw(struct sr_discipline *sd, int chunk, daddr_t blkno,
 	ccb->ccb_buf.b_vp = sc->src_vn;
 	ccb->ccb_buf.b_bq = NULL;
 
-	if (!ISSET(ccb->ccb_buf.b_flags, B_READ))
+	if (!ISSET(ccb->ccb_buf.b_flags, B_READ)) {
+		s = splbio();
 		ccb->ccb_buf.b_vp->v_numoutput++;
+		splx(s);
+	}
 
 	LIST_INIT(&ccb->ccb_buf.b_dep);
 
diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h
index f7dc8d8bc36..0ba69cdb12e 100644
--- a/sys/sys/vnode.h
+++ b/sys/sys/vnode.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vnode.h,v 1.164 2022/03/27 16:19:39 semarie Exp $	*/
+/*	$OpenBSD: vnode.h,v 1.165 2022/04/12 14:34:11 semarie Exp $	*/
 /*	$NetBSD: vnode.h,v 1.38 1996/02/29 20:59:05 cgd Exp $	*/
 
 /*
@@ -89,6 +89,7 @@ RBT_HEAD(namecache_rb_cache, namecache);
  * Locks used to protect struct members in struct vnode:
  *	a	atomic
  *	V	vnode_mtx
+ *	B	IPL_BIO
  */
 struct uvm_vnode;
 struct vnode {
@@ -113,7 +114,7 @@ struct vnode {
 	struct	buf_rb_bufs v_bufs_tree;	/* lookup of all bufs */
 	struct	buflists v_cleanblkhd;		/* clean blocklist head */
 	struct	buflists v_dirtyblkhd;		/* dirty blocklist head */
-	u_int   v_numoutput;			/* num of writes in progress */
+	u_int   v_numoutput;		/* [B] num of writes in progress */
 	LIST_ENTRY(vnode) v_synclist;		/* vnode with dirty buffers */
 	union {
 		struct mount	*vu_mountedhere;/* ptr to mounted vfs (VDIR) */