From e96a60dd2786961389241d23ed0a7339ad562315 Mon Sep 17 00:00:00 2001
From: des <des@FreeBSD.org>
Date: Tue, 2 Oct 2001 22:22:42 +0000
Subject: Add a PFS_DISABLED flag; pfs_visible() automatically returns 0 if it
 is set on the node in question.  Also add two API functions for setting and
 clearing this flag; setting it also reclaims all vnodes associated with the
 node.

---
 sys/fs/pseudofs/pseudofs.h         |  7 +++++++
 sys/fs/pseudofs/pseudofs_vncache.c | 38 ++++++++++++++++++++++++++++++++++++++
 sys/fs/pseudofs/pseudofs_vnops.c   | 22 ++++++++++++----------
 3 files changed, 57 insertions(+), 10 deletions(-)

diff --git a/sys/fs/pseudofs/pseudofs.h b/sys/fs/pseudofs/pseudofs.h
index e925d92..8a6f918 100644
--- a/sys/fs/pseudofs/pseudofs.h
+++ b/sys/fs/pseudofs/pseudofs.h
@@ -57,6 +57,7 @@ typedef enum {
 #define PFS_RAWRD	0x0004	/* raw reader */
 #define	PFS_RAWWR	0x0008	/* raw writer */
 #define PFS_RAW		(PFS_RAWRD|PFS_RAWWR)
+#define PFS_DISABLED	0x8000	/* node is disabled */
 
 /*
  * Data structures
@@ -165,6 +166,12 @@ int	 pfs_init		(struct pfs_info *pi, struct vfsconf *vfc);
 int	 pfs_uninit		(struct pfs_info *pi, struct vfsconf *vfc);
 
 /*
+ * Other utility functions
+ */
+int	 pfs_disable		(struct pfs_node *pn);
+int	 pfs_enable		(struct pfs_node *pn);
+
+/*
  * Now for some initialization magic...
  */
 #define PSEUDOFS(name, root, version)					\
diff --git a/sys/fs/pseudofs/pseudofs_vncache.c b/sys/fs/pseudofs/pseudofs_vncache.c
index 191f85c..d040b08 100644
--- a/sys/fs/pseudofs/pseudofs_vncache.c
+++ b/sys/fs/pseudofs/pseudofs_vncache.c
@@ -92,6 +92,9 @@ void
 pfs_vncache_unload(void)
 {
 	rm_at_exit(pfs_exit);
+	if (pfs_vncache_entries != 0)
+		printf("pfs_vncache_unload(): %d entries remaining\n",
+		    pfs_vncache_entries);
 	mtx_destroy(&pfs_vncache_mutex);
 }
 
@@ -217,3 +220,38 @@ pfs_exit(struct proc *p)
 	}
 	mtx_unlock(&pfs_vncache_mutex);
 }
+
+/*
+ * Disable a pseudofs node, and free all vnodes associated with it
+ */
+int
+pfs_disable(struct pfs_node *pn)
+{
+	struct pfs_vdata *pvd, *prev;
+	
+	if (pn->pn_flags & PFS_DISABLED)
+		return (0);
+	mtx_lock(&pfs_vncache_mutex);
+	pn->pn_flags |= PFS_DISABLED;
+	/* see the comment about the double loop in pfs_exit() */
+	/* XXX linear search... not very efficient */
+	for (pvd = pfs_vncache; pvd != NULL; pvd = pvd->pvd_next) {
+		while (pvd != NULL && pvd->pvd_pn == pn) {
+			prev = pvd->pvd_prev;
+			vgone(pvd->pvd_vnode);
+			pvd = prev ? prev->pvd_next : pfs_vncache;
+		}
+	}
+	mtx_unlock(&pfs_vncache_mutex);
+	return (0);
+}
+
+/*
+ * Re-enable a disabled pseudofs node
+ */
+int
+pfs_enable(struct pfs_node *pn)
+{
+	pn->pn_flags &= ~PFS_DISABLED;
+	return (0);
+}
diff --git a/sys/fs/pseudofs/pseudofs_vnops.c b/sys/fs/pseudofs/pseudofs_vnops.c
index 305ed21..5a29b0c 100644
--- a/sys/fs/pseudofs/pseudofs_vnops.c
+++ b/sys/fs/pseudofs/pseudofs_vnops.c
@@ -77,17 +77,20 @@ pfs_visible(struct thread *td, struct pfs_node *pn, pid_t pid)
 	
 	PFS_TRACE(("%s (pid: %d, req: %d)",
 	    pn->pn_name, pid, td->td_proc->p_pid));
-	if (pid == NO_PID)
-		PFS_RETURN (1);
+
+	if (pn->pn_flags & PFS_DISABLED)
+		PFS_RETURN (0);
 	
 	r = 1;
-	if ((proc = pfind(pid)) == NULL)
-		PFS_RETURN (0);
-	/* XXX should lock td->td_proc? */
-	if (p_cansee(td->td_proc, proc) != 0 ||
-	    (pn->pn_vis != NULL && !(pn->pn_vis)(td, proc, pn)))
-		r = 0;
-	PROC_UNLOCK(proc);
+	if (pid != NO_PID) {
+		if ((proc = pfind(pid)) == NULL)
+			PFS_RETURN (0);
+		/* XXX should lock td->td_proc? */
+		if (p_cansee(td->td_proc, proc) != 0 ||
+		    (pn->pn_vis != NULL && !(pn->pn_vis)(td, proc, pn)))
+			r = 0;
+		PROC_UNLOCK(proc);
+	}
 	PFS_RETURN (r);
 }
 
@@ -150,7 +153,6 @@ pfs_getattr(struct vop_getattr_args *va)
 
 	switch (pn->pn_type) {
 	case pfstype_procdir:
-		/* XXX needs p_cansee */
 	case pfstype_root:
 	case pfstype_dir:
 		vap->va_mode = 0555;
-- 
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