svn commit: r351778 - stable/12/sys/fs/unionfs

[Konstantin Belousov]

Author: kib
Date: Tue Sep  3 19:34:32 2019
New Revision: 351778
URL: https://svnweb.freebsd.org/changeset/base/351778

Log:
  MFC r350504:
  Try to decrease the number of bugs in unionfs after the VV_TEXT flag removal.

Modified:
  stable/12/sys/fs/unionfs/union_subr.c
  stable/12/sys/fs/unionfs/union_vnops.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/fs/unionfs/union_subr.c
==============================================================================
--- stable/12/sys/fs/unionfs/union_subr.c	Tue Sep  3 19:30:02 2019	(r351777)
+++ stable/12/sys/fs/unionfs/union_subr.c	Tue Sep  3 19:34:32 2019	(r351778)
@@ -348,6 +348,13 @@ unionfs_noderem(struct vnode *vp, struct thread *td)
 	vp->v_vnlock = &(vp->v_lock);
 	vp->v_data = NULL;
 	vp->v_object = NULL;
+	if (vp->v_writecount > 0) {
+		if (uvp != NULL)
+			VOP_ADD_WRITECOUNT(uvp, -vp->v_writecount);
+		else if (lvp != NULL)
+			VOP_ADD_WRITECOUNT(lvp, -vp->v_writecount);
+	} else if (vp->v_writecount < 0)
+		vp->v_writecount = 0;
 	VI_UNLOCK(vp);
 
 	if (lvp != NULLVP)

Modified: stable/12/sys/fs/unionfs/union_vnops.c
==============================================================================
--- stable/12/sys/fs/unionfs/union_vnops.c	Tue Sep  3 19:30:02 2019	(r351777)
+++ stable/12/sys/fs/unionfs/union_vnops.c	Tue Sep  3 19:34:32 2019	(r351778)
@@ -2511,6 +2511,33 @@ unionfs_vptofh(struct vop_vptofh_args *ap)
 	return (EOPNOTSUPP);
 }
 
+static int
+unionfs_add_writecount(struct vop_add_writecount_args *ap)
+{
+	struct vnode *tvp, *vp;
+	struct unionfs_node *unp;
+	int error;
+
+	vp = ap->a_vp;
+	unp = VTOUNIONFS(vp);
+	tvp = unp->un_uppervp != NULL ? unp->un_uppervp : unp->un_lowervp;
+	VI_LOCK(vp);
+	/* text refs are bypassed to lowervp */
+	VNASSERT(vp->v_writecount >= 0, vp, ("wrong null writecount"));
+	VNASSERT(vp->v_writecount + ap->a_inc >= 0, vp,
+	    ("wrong writecount inc %d", ap->a_inc));
+	if (tvp != NULL)
+		error = VOP_ADD_WRITECOUNT(tvp, ap->a_inc);
+	else if (vp->v_writecount < 0)
+		error = ETXTBSY;
+	else
+		error = 0;
+	if (error == 0)
+		vp->v_writecount += ap->a_inc;
+	VI_UNLOCK(vp);
+	return (error);
+}
+
 struct vop_vector unionfs_vnodeops = {
 	.vop_default =		&default_vnodeops,
 
@@ -2559,4 +2586,5 @@ struct vop_vector unionfs_vnodeops = {
 	.vop_whiteout =		unionfs_whiteout,
 	.vop_write =		unionfs_write,
 	.vop_vptofh =		unionfs_vptofh,
+	.vop_add_writecount =	unionfs_add_writecount,
 };