From d9adbeafd8f8b1c2417a208874b621fe3a8fdb26 Mon Sep 17 00:00:00 2001
From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Sun, 9 Aug 2009 23:17:32 -0700
Subject: [PATCH] NFS - Cleanly unmount NFS on halt/shutdown/reboot

* Abort any in-transit RPCs, disallow new RPCs, and disconnect the
  socket (aka if TCP) when doing a forced NFS unmount.

  This fixes left over TCP sockets when doing a normal halt/shutdown/reboot.

* Related user processes will also unblock, but the unmount code will
  still block trying to look up the path and this commit does not quite
  solve that problem.
---
 sys/kern/vfs_mount.c     | 11 ++++++++---
 sys/vfs/nfs/nfs.h        |  2 +-
 sys/vfs/nfs/nfs_socket.c | 10 ++++++++++
 sys/vfs/nfs/nfs_vfsops.c | 25 +++++++++++++++++++------
 4 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index 4e069a1657..e228de68d6 100644
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -1103,9 +1103,14 @@ vflush(struct mount *mp, int rootrefs, int flags)
 		 * Get the filesystem root vnode. We can vput() it
 		 * immediately, since with rootrefs > 0, it won't go away.
 		 */
-		if ((error = VFS_ROOT(mp, &rootvp)) != 0)
-			return (error);
-		vput(rootvp);
+		if ((error = VFS_ROOT(mp, &rootvp)) != 0) {
+			if ((flags & FORCECLOSE) == 0)
+				return (error);
+			rootrefs = 0;
+			/* continue anyway */
+		}
+		if (rootrefs)
+			vput(rootvp);
 	}
 
 	vflush_info.busy = 0;
diff --git a/sys/vfs/nfs/nfs.h b/sys/vfs/nfs/nfs.h
index a2284033c9..40c1795b4c 100644
--- a/sys/vfs/nfs/nfs.h
+++ b/sys/vfs/nfs/nfs.h
@@ -161,7 +161,7 @@ struct nfs_args {
 #define	NFSMNT_MAXGRPS		0x00000020  /* set maximum grouplist size */
 #define	NFSMNT_INT		0x00000040  /* allow interrupts on hard mount */
 #define	NFSMNT_NOCONN		0x00000080  /* Don't Connect the socket */
-#define	NFSMNT_UNUSED0100	0x00000100
+#define	NFSMNT_FORCE		0x00000100  /* Forced unmount */
 #define	NFSMNT_NFSV3		0x00000200  /* Use NFS Version 3 protocol */
 #define	NFSMNT_KERB		0x00000400  /* Use Kerberos authentication */
 #define	NFSMNT_DUMBTIMR		0x00000800  /* Don't estimate rtt dynamically */
diff --git a/sys/vfs/nfs/nfs_socket.c b/sys/vfs/nfs/nfs_socket.c
index f7460d7c3c..9a9048de7f 100644
--- a/sys/vfs/nfs/nfs_socket.c
+++ b/sys/vfs/nfs/nfs_socket.c
@@ -196,6 +196,8 @@ nfs_connect(struct nfsmount *nmp, struct nfsreq *rep)
 	struct thread *td = &thread0; /* only used for socreate and sobind */
 
 	nmp->nm_so = NULL;
+	if (nmp->nm_flag & NFSMNT_FORCE)
+		return (EINVAL);
 	saddr = nmp->nm_nam;
 	error = socreate(saddr->sa_family, &nmp->nm_so, nmp->nm_sotype,
 		nmp->nm_soproto, td);
@@ -354,6 +356,8 @@ nfs_reconnect(struct nfsmount *nmp, struct nfsreq *rep)
 	while ((error = nfs_connect(nmp, rep)) != 0) {
 		if (error == EINTR || error == ERESTART)
 			return (EINTR);
+		if (error == EINVAL)
+			return (error);
 		(void) tsleep((caddr_t)&lbolt, 0, "nfscon", 0);
 	}
 
@@ -1244,6 +1248,12 @@ nfs_request_try(struct nfsreq *rep)
 	 */
 	nfsstats.rpcrequests++;
 
+	if (nmp->nm_flag & NFSMNT_FORCE) {
+		rep->r_flags |= R_SOFTTERM;
+		rep->r_flags &= ~R_LOCKED;
+		return (0);
+	}
+
 	/*
 	 * Chain request into list of outstanding requests. Be sure
 	 * to put it LAST so timer finds oldest requests first.  Note
diff --git a/sys/vfs/nfs/nfs_vfsops.c b/sys/vfs/nfs/nfs_vfsops.c
index f2eb747e15..51e9f06f27 100644
--- a/sys/vfs/nfs/nfs_vfsops.c
+++ b/sys/vfs/nfs/nfs_vfsops.c
@@ -1047,9 +1047,12 @@ nfs_unmount(struct mount *mp, int mntflags)
 	struct nfsmount *nmp;
 	int error, flags = 0;
 
-	if (mntflags & MNT_FORCE)
-		flags |= FORCECLOSE;
 	nmp = VFSTONFS(mp);
+	if (mntflags & MNT_FORCE) {
+		flags |= FORCECLOSE;
+		nmp->nm_flag |= NFSMNT_FORCE;
+	}
+
 	/*
 	 * Goes something like this..
 	 * - Call vflush() to clear out vnodes for this file system
@@ -1059,19 +1062,29 @@ nfs_unmount(struct mount *mp, int mntflags)
 	/* In the forced case, cancel any outstanding requests. */
 	if (flags & FORCECLOSE) {
 		error = nfs_nmcancelreqs(nmp);
-		if (error)
-			return (error);
+		if (error) {
+			kprintf("NFS: %s: Unable to cancel all requests\n",
+				mp->mnt_stat.f_mntfromname);
+			/* continue anyway */
+		}
 	}
+
 	/*
 	 * Must handshake with nfs_clientd() if it is active. XXX
 	 */
 	nmp->nm_state |= NFSSTA_DISMINPROG;
 
-	/* We hold 1 extra ref on the root vnode; see comment in mountnfs(). */
+	/*
+	 * We hold 1 extra ref on the root vnode; see comment in mountnfs().
+	 *
+	 * If this doesn't work and we are doing a forced unmount we continue
+	 * anyway.
+	 */
 	error = vflush(mp, 1, flags);
 	if (error) {
 		nmp->nm_state &= ~NFSSTA_DISMINPROG;
-		return (error);
+		if ((flags & FORCECLOSE) == 0)
+			return (error);
 	}
 
 	/*
-- 
2.41.0