From: claudio <claudio@openbsd.org>
Date: Mon, 25 Oct 2021 10:24:54 +0000 (+0000)
Subject: Revert commitid: ufM9BcSbXqfLpzBH;
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=8e49fb4c2a30057c387ac447b5598aa90b4ad4fa;p=openbsd

Revert commitid: ufM9BcSbXqfLpzBH;
Move vfs_stall_barrier() from the fd layer into vn_lock() and the vfs layer.
In some cases it can result in a deadlock while suspending.
Discussed with mpi@ and deraadt@
---

diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index ea3e3399ce0..17d9deaf54d 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_descrip.c,v 1.203 2021/10/21 09:59:13 claudio Exp $	*/
+/*	$OpenBSD: kern_descrip.c,v 1.204 2021/10/25 10:24:54 claudio Exp $	*/
 /*	$NetBSD: kern_descrip.c,v 1.42 1996/03/30 22:24:38 christos Exp $	*/
 
 /*
@@ -232,6 +232,8 @@ fd_getfile(struct filedesc *fdp, int fd)
 {
 	struct file *fp;
 
+	vfs_stall_barrier();
+
 	if ((u_int)fd >= fdp->fd_nfiles)
 		return (NULL);
 
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index f8a300a3007..43a7cbd4ae9 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vfs_subr.c,v 1.312 2021/10/24 00:02:25 jsg Exp $	*/
+/*	$OpenBSD: vfs_subr.c,v 1.313 2021/10/25 10:24:54 claudio Exp $	*/
 /*	$NetBSD: vfs_subr.c,v 1.53 1996/04/22 01:39:13 christos Exp $	*/
 
 /*
@@ -1705,10 +1705,8 @@ void
 vfs_stall_barrier(void)
 {
 	if (__predict_false(vfs_stalling)) {
-		if (curproc != RWLOCK_OWNER(&vfs_stall_lock)) {
-			rw_enter_read(&vfs_stall_lock);
-			rw_exit_read(&vfs_stall_lock);
-		}
+		rw_enter_read(&vfs_stall_lock);
+		rw_exit_read(&vfs_stall_lock);
 	}
 }
 
diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index de6d7593b14..5f89a6c2ef8 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vfs_vnops.c,v 1.117 2021/10/21 09:59:14 claudio Exp $	*/
+/*	$OpenBSD: vfs_vnops.c,v 1.118 2021/10/25 10:24:54 claudio Exp $	*/
 /*	$NetBSD: vfs_vnops.c,v 1.20 1996/02/04 02:18:41 christos Exp $	*/
 
 /*
@@ -565,8 +565,6 @@ vn_lock(struct vnode *vp, int flags)
 {
 	int error, xlocked, do_wakeup;
 
-	vfs_stall_barrier();
-
 	do {
 		mtx_enter(&vnode_mtx);
 		if (vp->v_lflag & VXLOCK) {
diff --git a/sys/sys/file.h b/sys/sys/file.h
index b440e1275c5..19136100ed8 100644
--- a/sys/sys/file.h
+++ b/sys/sys/file.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: file.h,v 1.63 2021/10/21 09:59:14 claudio Exp $	*/
+/*	$OpenBSD: file.h,v 1.64 2021/10/25 10:24:54 claudio Exp $	*/
 /*	$NetBSD: file.h,v 1.11 1995/03/26 20:24:13 jtc Exp $	*/
 
 /*
@@ -106,7 +106,11 @@ struct file {
 #define FIF_INSERTED		0x80	/* present in `filehead' */
 
 #define FREF(fp) \
-	atomic_inc_int(&(fp)->f_count)
+	do { \
+		extern void vfs_stall_barrier(void); \
+		vfs_stall_barrier(); \
+		atomic_inc_int(&(fp)->f_count); \
+	} while (0)
 
 #define FRELE(fp,p) \
 	(atomic_dec_int_nv(&fp->f_count) == 0 ? fdrop(fp, p) : 0)