Module Name:    src
Committed By:   riastradh
Date:           Mon Mar 28 12:37:46 UTC 2022

Modified Files:
        src/sys/coda: coda_vfsops.c
        src/sys/kern: vfs_mount.c vfs_subr.c vfs_vnode.c
        src/sys/miscfs/specfs: spec_vnops.c specdev.h

Log Message:
specfs: Let spec_node_lookup_by_dev wait for reclaim to finish.

vdevgone relies on this to ensure that if there is a concurrent
revoke in progress, it will wait for that revoke to finish -- that
way, it can guarantee all I/O operations have completed and the
device is closed.


To generate a diff of this commit:
cvs rdiff -u -r1.89 -r1.90 src/sys/coda/coda_vfsops.c
cvs rdiff -u -r1.91 -r1.92 src/sys/kern/vfs_mount.c
cvs rdiff -u -r1.491 -r1.492 src/sys/kern/vfs_subr.c
cvs rdiff -u -r1.139 -r1.140 src/sys/kern/vfs_vnode.c
cvs rdiff -u -r1.207 -r1.208 src/sys/miscfs/specfs/spec_vnops.c
cvs rdiff -u -r1.50 -r1.51 src/sys/miscfs/specfs/specdev.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/coda/coda_vfsops.c
diff -u src/sys/coda/coda_vfsops.c:1.89 src/sys/coda/coda_vfsops.c:1.90
--- src/sys/coda/coda_vfsops.c:1.89	Fri Nov 20 10:08:47 2020
+++ src/sys/coda/coda_vfsops.c	Mon Mar 28 12:37:46 2022
@@ -1,4 +1,4 @@
-/*	$NetBSD: coda_vfsops.c,v 1.89 2020/11/20 10:08:47 hannken Exp $	*/
+/*	$NetBSD: coda_vfsops.c,v 1.90 2022/03/28 12:37:46 riastradh Exp $	*/
 
 /*
  *
@@ -45,7 +45,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: coda_vfsops.c,v 1.89 2020/11/20 10:08:47 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: coda_vfsops.c,v 1.90 2022/03/28 12:37:46 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -636,7 +636,7 @@ struct mount *devtomp(dev_t dev)
     struct mount *mp;
     struct vnode *vp;
 
-    if (spec_node_lookup_by_dev(VBLK, dev, &vp) == 0) {
+    if (spec_node_lookup_by_dev(VBLK, dev, VDEAD_NOWAIT, &vp) == 0) {
 	mp = spec_node_getmountedfs(vp);
 	vrele(vp);
     } else {

Index: src/sys/kern/vfs_mount.c
diff -u src/sys/kern/vfs_mount.c:1.91 src/sys/kern/vfs_mount.c:1.92
--- src/sys/kern/vfs_mount.c:1.91	Thu Mar 24 12:59:56 2022
+++ src/sys/kern/vfs_mount.c	Mon Mar 28 12:37:46 2022
@@ -1,4 +1,4 @@
-/*	$NetBSD: vfs_mount.c,v 1.91 2022/03/24 12:59:56 riastradh Exp $	*/
+/*	$NetBSD: vfs_mount.c,v 1.92 2022/03/28 12:37:46 riastradh Exp $	*/
 
 /*-
  * Copyright (c) 1997-2020 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.91 2022/03/24 12:59:56 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.92 2022/03/28 12:37:46 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -1376,7 +1376,8 @@ vfs_mountedon(vnode_t *vp)
 		return ENOTBLK;
 	if (spec_node_getmountedfs(vp) != NULL)
 		return EBUSY;
-	if (spec_node_lookup_by_dev(vp->v_type, vp->v_rdev, &vq) == 0) {
+	if (spec_node_lookup_by_dev(vp->v_type, vp->v_rdev, VDEAD_NOWAIT, &vq)
+	    == 0) {
 		if (spec_node_getmountedfs(vq) != NULL)
 			error = EBUSY;
 		vrele(vq);

Index: src/sys/kern/vfs_subr.c
diff -u src/sys/kern/vfs_subr.c:1.491 src/sys/kern/vfs_subr.c:1.492
--- src/sys/kern/vfs_subr.c:1.491	Sat Oct 16 07:12:01 2021
+++ src/sys/kern/vfs_subr.c	Mon Mar 28 12:37:46 2022
@@ -1,4 +1,4 @@
-/*	$NetBSD: vfs_subr.c,v 1.491 2021/10/16 07:12:01 simonb Exp $	*/
+/*	$NetBSD: vfs_subr.c,v 1.492 2022/03/28 12:37:46 riastradh Exp $	*/
 
 /*-
  * Copyright (c) 1997, 1998, 2004, 2005, 2007, 2008, 2019, 2020
@@ -69,7 +69,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.491 2021/10/16 07:12:01 simonb Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.492 2022/03/28 12:37:46 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddb.h"
@@ -495,7 +495,7 @@ int
 vfinddev(dev_t dev, enum vtype type, vnode_t **vpp)
 {
 
-	return (spec_node_lookup_by_dev(type, dev, vpp) == 0);
+	return (spec_node_lookup_by_dev(type, dev, VDEAD_NOWAIT, vpp) == 0);
 }
 
 /*
@@ -511,7 +511,12 @@ vdevgone(int maj, int minl, int minh, en
 
 	for (mn = minl; mn <= minh; mn++) {
 		dev = makedev(maj, mn);
-		while (spec_node_lookup_by_dev(type, dev, &vp) == 0) {
+		/*
+		 * Passing 0 as flags, instead of VDEAD_NOWAIT, means
+		 * spec_node_lookup_by_dev will wait for vnodes it
+		 * finds concurrently being revoked before returning.
+		 */
+		while (spec_node_lookup_by_dev(type, dev, 0, &vp) == 0) {
 			VOP_REVOKE(vp, REVOKEALL);
 			vrele(vp);
 		}

Index: src/sys/kern/vfs_vnode.c
diff -u src/sys/kern/vfs_vnode.c:1.139 src/sys/kern/vfs_vnode.c:1.140
--- src/sys/kern/vfs_vnode.c:1.139	Sat Mar 19 13:53:32 2022
+++ src/sys/kern/vfs_vnode.c	Mon Mar 28 12:37:46 2022
@@ -1,4 +1,4 @@
-/*	$NetBSD: vfs_vnode.c,v 1.139 2022/03/19 13:53:32 hannken Exp $	*/
+/*	$NetBSD: vfs_vnode.c,v 1.140 2022/03/28 12:37:46 riastradh Exp $	*/
 
 /*-
  * Copyright (c) 1997-2011, 2019, 2020 The NetBSD Foundation, Inc.
@@ -148,7 +148,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.139 2022/03/19 13:53:32 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.140 2022/03/28 12:37:46 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_pax.h"
@@ -1231,7 +1231,8 @@ vrevoke(vnode_t *vp)
 		type = vp->v_type;
 		mutex_exit(vp->v_interlock);
 
-		while (spec_node_lookup_by_dev(type, dev, &vq) == 0) {
+		while (spec_node_lookup_by_dev(type, dev, VDEAD_NOWAIT, &vq)
+		    == 0) {
 			mp = vrevoke_suspend_next(mp, vq->v_mount);
 			vgone(vq);
 		}

Index: src/sys/miscfs/specfs/spec_vnops.c
diff -u src/sys/miscfs/specfs/spec_vnops.c:1.207 src/sys/miscfs/specfs/spec_vnops.c:1.208
--- src/sys/miscfs/specfs/spec_vnops.c:1.207	Mon Mar 28 12:37:35 2022
+++ src/sys/miscfs/specfs/spec_vnops.c	Mon Mar 28 12:37:46 2022
@@ -1,4 +1,4 @@
-/*	$NetBSD: spec_vnops.c,v 1.207 2022/03/28 12:37:35 riastradh Exp $	*/
+/*	$NetBSD: spec_vnops.c,v 1.208 2022/03/28 12:37:46 riastradh Exp $	*/
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -58,7 +58,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: spec_vnops.c,v 1.207 2022/03/28 12:37:35 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: spec_vnops.c,v 1.208 2022/03/28 12:37:46 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -424,18 +424,35 @@ spec_node_init(vnode_t *vp, dev_t rdev)
  * Lookup a vnode by device number and return it referenced.
  */
 int
-spec_node_lookup_by_dev(enum vtype type, dev_t dev, vnode_t **vpp)
+spec_node_lookup_by_dev(enum vtype type, dev_t dev, int flags, vnode_t **vpp)
 {
 	int error;
 	vnode_t *vp;
 
-	mutex_enter(&device_lock);
+top:	mutex_enter(&device_lock);
 	for (vp = specfs_hash[SPECHASH(dev)]; vp; vp = vp->v_specnext) {
 		if (type == vp->v_type && dev == vp->v_rdev) {
 			mutex_enter(vp->v_interlock);
 			/* If clean or being cleaned, then ignore it. */
 			if (vdead_check(vp, VDEAD_NOWAIT) == 0)
 				break;
+			if ((flags & VDEAD_NOWAIT) == 0) {
+				mutex_exit(&device_lock);
+				/*
+				 * It may be being revoked as we speak,
+				 * and the caller wants to wait until
+				 * all revocation has completed.  Let
+				 * vcache_vget wait for it to finish
+				 * dying; as a side effect, vcache_vget
+				 * releases vp->v_interlock.  Note that
+				 * vcache_vget cannot succeed at this
+				 * point because vdead_check already
+				 * failed.
+				 */
+				error = vcache_vget(vp);
+				KASSERT(error);
+				goto top;
+			}
 			mutex_exit(vp->v_interlock);
 		}
 	}

Index: src/sys/miscfs/specfs/specdev.h
diff -u src/sys/miscfs/specfs/specdev.h:1.50 src/sys/miscfs/specfs/specdev.h:1.51
--- src/sys/miscfs/specfs/specdev.h:1.50	Mon Mar 28 12:37:09 2022
+++ src/sys/miscfs/specfs/specdev.h	Mon Mar 28 12:37:46 2022
@@ -1,4 +1,4 @@
-/*	$NetBSD: specdev.h,v 1.50 2022/03/28 12:37:09 riastradh Exp $	*/
+/*	$NetBSD: specdev.h,v 1.51 2022/03/28 12:37:46 riastradh Exp $	*/
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -95,7 +95,7 @@ typedef struct specdev {
  */
 void	spec_node_init(vnode_t *, dev_t);
 void	spec_node_destroy(vnode_t *);
-int	spec_node_lookup_by_dev(enum vtype, dev_t, vnode_t **);
+int	spec_node_lookup_by_dev(enum vtype, dev_t, int, vnode_t **);
 int	spec_node_lookup_by_mount(struct mount *, vnode_t **);
 struct mount *spec_node_getmountedfs(vnode_t *);
 void	spec_node_setmountedfs(vnode_t *, struct mount *);

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