[src/trunk]: src/sys/dev/dkwedge Copy mode of open wedges with the same paren...

[mlelstv <mlelstv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b67e52d182ec
branches:  trunk
changeset: 1021515:b67e52d182ec
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Wed Jun 02 15:59:08 2021 +0000

description:
Copy mode of open wedges with the same parent and validate it.
Remove race on mode value when closing.

diffstat:

 sys/dev/dkwedge/dk.c |  36 ++++++++++++++++++++++++++----------
 1 files changed, 26 insertions(+), 10 deletions(-)

diffs (89 lines):

diff -r 942c483264da -r b67e52d182ec sys/dev/dkwedge/dk.c
--- a/sys/dev/dkwedge/dk.c      Wed Jun 02 15:45:28 2021 +0000
+++ b/sys/dev/dkwedge/dk.c      Wed Jun 02 15:59:08 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: dk.c,v 1.103 2021/05/22 13:43:50 mlelstv Exp $ */
+/*     $NetBSD: dk.c,v 1.104 2021/06/02 15:59:08 mlelstv Exp $ */
 
 /*-
  * Copyright (c) 2004, 2005, 2006, 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.103 2021/05/22 13:43:50 mlelstv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.104 2021/06/02 15:59:08 mlelstv Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_dkwedge.h"
@@ -1137,6 +1137,7 @@
 dkopen(dev_t dev, int flags, int fmt, struct lwp *l)
 {
        struct dkwedge_softc *sc = dkwedge_lookup(dev);
+       struct dkwedge_softc *nsc;
        struct vnode *vp;
        int error = 0;
        int mode;
@@ -1169,13 +1170,24 @@
                        }
                        if (error)
                                goto popen_fail;
-                       /* remember open mode */
-                       sc->sc_mode = mode;
                        sc->sc_parent->dk_rawvp = vp;
+               } else {
+                       /*
+                        * Retrieve mode from an already opened wedge.
+                        */
+                       mode = 0;
+                       LIST_FOREACH(nsc, &sc->sc_parent->dk_wedges, sc_plink) {
+                               if (nsc == sc || nsc->sc_dk.dk_openmask == 0)
+                                       continue;
+                               mode = nsc->sc_mode;
+                               break;
+                       }
                }
+               sc->sc_mode = mode;
                sc->sc_parent->dk_rawopens++;
-       } else if (flags & ~sc->sc_mode & FWRITE) {
-               /* parent is opened read-only, cannot open read-write */
+       }
+       KASSERT(sc->sc_mode != 0);
+       if (flags & ~sc->sc_mode & FWRITE) {
                error = EROFS;
                goto popen_fail;
        }
@@ -1199,7 +1211,9 @@
 dklastclose(struct dkwedge_softc *sc)
 {
        struct vnode *vp;
-       int error = 0;
+       int error = 0, mode;
+
+       mode = sc->sc_mode;
 
        vp = NULL;
        if (sc->sc_parent->dk_rawopens > 0) {
@@ -1214,7 +1228,7 @@
        mutex_exit(&sc->sc_dk.dk_openlock);
 
        if (vp) {
-               dk_close_parent(vp, sc->sc_mode);
+               dk_close_parent(vp, mode);
        }
 
        return error;
@@ -1248,9 +1262,11 @@
        sc->sc_dk.dk_openmask =
            sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
 
-       if (sc->sc_dk.dk_openmask == 0)
+       if (sc->sc_dk.dk_openmask == 0) {
                error = dklastclose(sc); /* releases locks */
-       else {
+               sc->sc_mode = 0;
+       } else {
+               sc->sc_mode = 0;
                mutex_exit(&sc->sc_parent->dk_rawlock);
                mutex_exit(&sc->sc_dk.dk_openlock);
        }