Index: sys/kern/vfs_subr.c
===================================================================
--- sys/kern/vfs_subr.c
+++ sys/kern/vfs_subr.c
@@ -50,6 +50,7 @@
 #include <sys/systm.h>
 #include <sys/bio.h>
 #include <sys/buf.h>
+#include <sys/capsicum.h>
 #include <sys/condvar.h>
 #include <sys/conf.h>
 #include <sys/counter.h>
@@ -338,6 +339,93 @@
 static int vnlru_nowhere;
 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
     &vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
+
+static int
+sysctl_try_reclaim_vnode(SYSCTL_HANDLER_ARGS)
+{
+	struct vnode *vp;
+	struct nameidata nd;
+	char *buf;
+	unsigned long ndflags;
+	int error;
+
+	if (req->newptr == NULL)
+		return (EINVAL);
+	if (req->newlen > PATH_MAX)
+		return (E2BIG);
+
+	buf = malloc(PATH_MAX + 1, M_TEMP, M_WAITOK);
+	error = SYSCTL_IN(req, buf, req->newlen);
+	if (error != 0)
+		goto out;
+
+	buf[req->newlen] = '\0';
+
+	ndflags = LOCKLEAF | NOFOLLOW | AUDITVNODE1 | NOCACHE | SAVENAME;
+	NDINIT(&nd, LOOKUP, ndflags, UIO_SYSSPACE, buf, curthread);
+	if ((error = namei(&nd)) != 0)
+		goto out;
+	vp = nd.ni_vp;
+
+	if ((vp->v_iflag & VI_DOOMED) != 0) {
+		/*
+		 * This vnode is being recycled.  Return != 0 to let the caller
+		 * know that the sysctl had no effect.  Return EAGAIN because a
+		 * subsequent call will likely succeed (since namei will create
+		 * a new vnode if necessary)
+		 */
+		error = EAGAIN;
+		goto putvnode;
+	}
+
+	counter_u64_add(recycles_count, 1);
+	vgone(vp);
+putvnode:
+	NDFREE(&nd, 0);
+out:
+	free(buf, M_TEMP);
+	return (error);
+}
+
+static int
+sysctl_ftry_reclaim_vnode(SYSCTL_HANDLER_ARGS)
+{
+	struct thread *td = curthread;
+	struct vnode *vp;
+	struct file *fp;
+	int error;
+	int fd = -1;
+
+	if (req->newptr == NULL)
+		return (EBADF);
+
+        error = sysctl_handle_int(oidp, &fd, 0, req);
+        if (error != 0)
+                return (error);
+	error = getvnode(curthread, fd, &cap_fcntl_rights, &fp);
+	if (error != 0)
+		return (error);
+	vp = fp->f_vnode;
+
+	error = vn_lock(vp, LK_EXCLUSIVE);
+	if (error != 0)
+		goto drop;
+
+	counter_u64_add(recycles_count, 1);
+	vgone(vp);
+	VOP_UNLOCK(vp, 0);
+drop:
+	fdrop(fp, td);
+	return (error);
+}
+
+SYSCTL_PROC(_debug, OID_AUTO, try_reclaim_vnode,
+    CTLTYPE_STRING | CTLFLAG_MPSAFE | CTLFLAG_WR, NULL, 0,
+    sysctl_try_reclaim_vnode, "A", "Try to reclaim a vnode by its pathname");
+SYSCTL_PROC(_debug, OID_AUTO, ftry_reclaim_vnode,
+    CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_WR, NULL, 0,
+    sysctl_ftry_reclaim_vnode, "I",
+    "Try to reclaim a vnode by its file descriptor");
 
 /* Shift count for (uintptr_t)vp to initialize vp->v_hash. */
 static int vnsz2log;