[src/trunk]: src/sys/miscfs Handle v_writecount from layer_open(), layer_clos...

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

details:   https://anonhg.NetBSD.org/src/rev/3e2ff3a8b981
branches:  trunk
changeset: 821180:3e2ff3a8b981
user:      hannken <hannken%NetBSD.org@localhost>
date:      Fri Jan 27 10:47:13 2017 +0000

description:
Handle v_writecount from layer_open(), layer_close() and layer_revoke()
so lower file system vnodes get marked as open for writing.

diffstat:

 sys/miscfs/genfs/layer_extern.h    |   3 +-
 sys/miscfs/genfs/layer_vnops.c     |  50 ++++++++++++++++++++++++++++++++++---
 sys/miscfs/nullfs/null_vnops.c     |   5 ++-
 sys/miscfs/overlay/overlay_vnops.c |   7 +++--
 sys/miscfs/umapfs/umap_vnops.c     |   5 ++-
 5 files changed, 57 insertions(+), 13 deletions(-)

diffs (202 lines):

diff -r ce48695e6e36 -r 3e2ff3a8b981 sys/miscfs/genfs/layer_extern.h
--- a/sys/miscfs/genfs/layer_extern.h   Fri Jan 27 10:46:18 2017 +0000
+++ b/sys/miscfs/genfs/layer_extern.h   Fri Jan 27 10:47:13 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: layer_extern.h,v 1.36 2014/05/25 13:51:25 hannken Exp $        */
+/*     $NetBSD: layer_extern.h,v 1.37 2017/01/27 10:47:13 hannken Exp $        */
 
 /*
  * Copyright (c) 1999 National Aeronautics & Space Administration
@@ -106,6 +106,7 @@
 int    layer_setattr(void *);
 int    layer_access(void *);
 int    layer_open(void *);
+int    layer_close(void *);
 int    layer_remove(void *);
 int    layer_rename(void *);
 int    layer_revoke(void *);
diff -r ce48695e6e36 -r 3e2ff3a8b981 sys/miscfs/genfs/layer_vnops.c
--- a/sys/miscfs/genfs/layer_vnops.c    Fri Jan 27 10:46:18 2017 +0000
+++ b/sys/miscfs/genfs/layer_vnops.c    Fri Jan 27 10:47:13 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: layer_vnops.c,v 1.59 2016/08/20 12:37:09 hannken Exp $ */
+/*     $NetBSD: layer_vnops.c,v 1.60 2017/01/27 10:47:13 hannken Exp $ */
 
 /*
  * Copyright (c) 1999 National Aeronautics & Space Administration
@@ -170,7 +170,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: layer_vnops.c,v 1.59 2016/08/20 12:37:09 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: layer_vnops.c,v 1.60 2017/01/27 10:47:13 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -182,6 +182,7 @@
 #include <sys/kmem.h>
 #include <sys/buf.h>
 #include <sys/kauth.h>
+#include <sys/fcntl.h>
 
 #include <miscfs/genfs/layer.h>
 #include <miscfs/genfs/layer_extern.h>
@@ -491,7 +492,8 @@
 }
 
 /*
- * We must handle open to be able to catch MNT_NODEV and friends.
+ * We must handle open to be able to catch MNT_NODEV and friends
+ * and increment the lower v_writecount.
  */
 int
 layer_open(void *v)
@@ -503,12 +505,43 @@
                kauth_cred_t a_cred;
        } */ *ap = v;
        struct vnode *vp = ap->a_vp;
-       enum vtype lower_type = LAYERVPTOLOWERVP(vp)->v_type;
+       struct vnode *lvp = LAYERVPTOLOWERVP(vp);
+       int error;
 
-       if (((lower_type == VBLK) || (lower_type == VCHR)) &&
+       if (((lvp->v_type == VBLK) || (lvp->v_type == VCHR)) &&
            (vp->v_mount->mnt_flag & MNT_NODEV))
                return ENXIO;
 
+       error = LAYERFS_DO_BYPASS(vp, ap);
+       if (error == 0 && (ap->a_mode & FWRITE)) {
+               mutex_enter(lvp->v_interlock);
+               lvp->v_writecount++;
+               mutex_exit(lvp->v_interlock);
+       }
+       return error;
+}
+
+/*
+ * We must handle close to decrement the lower v_writecount.
+ */
+int
+layer_close(void *v)
+{
+       struct vop_close_args /* {
+               const struct vnodeop_desc *a_desc;
+               struct vnode *a_vp;
+               int a_fflag;
+               kauth_cred_t a_cred;
+       } */ *ap = v;
+       struct vnode *vp = ap->a_vp;
+       struct vnode *lvp = LAYERVPTOLOWERVP(vp);
+
+       if ((ap->a_fflag & FWRITE)) {
+               mutex_enter(lvp->v_interlock);
+               KASSERT(lvp->v_writecount > 0);
+               lvp->v_writecount--;
+               mutex_exit(lvp->v_interlock);
+       }
        return LAYERFS_DO_BYPASS(vp, ap);
 }
 
@@ -660,8 +693,15 @@
         * We will most likely end up in vclean which uses the v_usecount
         * to determine if a vnode is active.  Take an extra reference on
         * the lower vnode so it will always close and inactivate.
+        * Remove our writecount from the lower vnode.
         */
        vref(lvp);
+
+       mutex_enter(vp->v_interlock);
+       KASSERT(vp->v_interlock == lvp->v_interlock);
+       lvp->v_writecount -= vp->v_writecount;
+       mutex_exit(vp->v_interlock);
+
        error = LAYERFS_DO_BYPASS(vp, ap);
        vrele(lvp);
 
diff -r ce48695e6e36 -r 3e2ff3a8b981 sys/miscfs/nullfs/null_vnops.c
--- a/sys/miscfs/nullfs/null_vnops.c    Fri Jan 27 10:46:18 2017 +0000
+++ b/sys/miscfs/nullfs/null_vnops.c    Fri Jan 27 10:47:13 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: null_vnops.c,v 1.39 2014/02/27 16:51:38 hannken Exp $  */
+/*     $NetBSD: null_vnops.c,v 1.40 2017/01/27 10:47:13 hannken Exp $  */
 
 /*
  * Copyright (c) 1999 National Aeronautics & Space Administration
@@ -80,7 +80,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: null_vnops.c,v 1.39 2014/02/27 16:51:38 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: null_vnops.c,v 1.40 2017/01/27 10:47:13 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -114,6 +114,7 @@
        { &vop_rmdir_desc,      layer_rmdir },
 
        { &vop_open_desc,       layer_open },   /* mount option handling */
+       { &vop_close_desc,      layer_close },
 
        { &vop_bmap_desc,       layer_bmap },
        { &vop_getpages_desc,   layer_getpages },
diff -r ce48695e6e36 -r 3e2ff3a8b981 sys/miscfs/overlay/overlay_vnops.c
--- a/sys/miscfs/overlay/overlay_vnops.c        Fri Jan 27 10:46:18 2017 +0000
+++ b/sys/miscfs/overlay/overlay_vnops.c        Fri Jan 27 10:47:13 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: overlay_vnops.c,v 1.21 2014/11/10 18:46:33 maxv Exp $  */
+/*     $NetBSD: overlay_vnops.c,v 1.22 2017/01/27 10:47:13 hannken Exp $       */
 
 /*
  * Copyright (c) 1999, 2000 National Aeronautics & Space Administration
@@ -67,7 +67,7 @@
  *
  * Ancestors:
  *     @(#)lofs_vnops.c        1.2 (Berkeley) 6/18/92
- *     $Id: overlay_vnops.c,v 1.21 2014/11/10 18:46:33 maxv Exp $
+ *     $Id: overlay_vnops.c,v 1.22 2017/01/27 10:47:13 hannken Exp $
  *     ...and...
  *     @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project
  */
@@ -126,7 +126,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: overlay_vnops.c,v 1.21 2014/11/10 18:46:33 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: overlay_vnops.c,v 1.22 2017/01/27 10:47:13 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -162,6 +162,7 @@
        { &vop_rmdir_desc,    layer_rmdir },
 
        { &vop_open_desc,     layer_open },     /* mount option handling */
+       { &vop_close_desc,    layer_close },
 
        { &vop_bmap_desc,     layer_bmap },
        { &vop_getpages_desc, layer_getpages },
diff -r ce48695e6e36 -r 3e2ff3a8b981 sys/miscfs/umapfs/umap_vnops.c
--- a/sys/miscfs/umapfs/umap_vnops.c    Fri Jan 27 10:46:18 2017 +0000
+++ b/sys/miscfs/umapfs/umap_vnops.c    Fri Jan 27 10:47:13 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: umap_vnops.c,v 1.57 2014/11/09 18:08:07 maxv Exp $     */
+/*     $NetBSD: umap_vnops.c,v 1.58 2017/01/27 10:47:13 hannken Exp $  */
 
 /*
  * Copyright (c) 1992, 1993
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: umap_vnops.c,v 1.57 2014/11/09 18:08:07 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: umap_vnops.c,v 1.58 2017/01/27 10:47:13 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -90,6 +90,7 @@
        { &vop_reclaim_desc,    layer_reclaim },
        { &vop_lock_desc,       layer_lock },
        { &vop_open_desc,       layer_open },
+       { &vop_close_desc,      layer_close },
        { &vop_setattr_desc,    layer_setattr },
        { &vop_access_desc,     layer_access },
        { &vop_remove_desc,     layer_remove },