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 ea3e339..17d9dea 100644 (file)
--- 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 f8a300a..43a7cbd 100644 (file)
--- 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 de6d759..5f89a6c 100644 (file)
--- 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 b440e12..1913610 100644 (file)
--- 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)