Pull in FreeBSD r37363 and r37887:

--
Sync timestamp changes for inodes of special files to disk as late
as possible (when the inode is reclaimed).  Temporarily only do
this if option UFS_LAZYMOD configured and softupdates aren't enabled.
UFS_LAZYMOD is intentionally left out of /sys/conf/options.

This is mainly to avoid almost useless disk i/o on battery powered
machines.  It's silly to write to disk (on the next sync or when the
inode becomes inactive) just because someone hit a key or something
wrote to the screen or /dev/null.
--
Made lazy syncing of timestamps for special files non-optional.
--

Also, include support in 'pstat -v' to display the IN_LAZYMOD flag.

ok tedu@ millert@

4 files changed, 25 insertions, 9 deletions

diff --git a/sys/ufs/ffs/ffs_inode.c b/sys/ufs/ffs/ffs_inode.c
index 80a1b1c11e9..641e596e7dd 100644
--- a/sys/ufs/ffs/ffs_inode.c
+++ b/sys/ufs/ffs/ffs_inode.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ffs_inode.c,v 1.67 2014/01/25 23:31:12 guenther Exp $	*/
+/*	$OpenBSD: ffs_inode.c,v 1.68 2014/03/19 04:17:33 guenther Exp $	*/
 /*	$NetBSD: ffs_inode.c,v 1.10 1996/05/11 18:27:19 mycroft Exp $	*/
 
 /*
@@ -59,8 +59,11 @@ int ffs_indirtrunc(struct inode *, daddr_t, daddr_t, daddr_t, int, long *);
  * Update the access, modified, and inode change times as specified by the
  * IN_ACCESS, IN_UPDATE, and IN_CHANGE flags respectively. The IN_MODIFIED
  * flag is used to specify that the inode needs to be updated but that the
- * times have already been set.  If waitfor is set, then wait for
- * the disk write of the inode to complete.
+ * times have already been set.  The IN_LAZYMOD flag is used to specify
+ * that the inode needs to be updated at some point, by reclaim if not
+ * in the course of other changes; this is used to defer writes just to
+ * update device timestamps.  If waitfor is set, then wait for the disk
+ * write of the inode to complete.
  */
 int
 ffs_update(struct inode *ip, int waitfor)
@@ -76,7 +79,7 @@ ffs_update(struct inode *ip, int waitfor)
 	if ((ip->i_flag & IN_MODIFIED) == 0 && waitfor != MNT_WAIT)
 		return (0);
 
-	ip->i_flag &= ~IN_MODIFIED;
+	ip->i_flag &= ~(IN_MODIFIED | IN_LAZYMOD);
 	fs = ip->i_fs;
 
 	/*
diff --git a/sys/ufs/ufs/inode.h b/sys/ufs/ufs/inode.h
index 3b730c08254..ae721caad4d 100644
--- a/sys/ufs/ufs/inode.h
+++ b/sys/ufs/ufs/inode.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: inode.h,v 1.42 2014/01/26 02:02:26 tedu Exp $	*/
+/*	$OpenBSD: inode.h,v 1.43 2014/03/19 04:17:33 guenther Exp $	*/
 /*	$NetBSD: inode.h,v 1.8 1995/06/15 23:22:50 cgd Exp $	*/
 
 /*
@@ -250,6 +250,7 @@ struct inode_vtbl {
 #define	IN_RENAME	0x0010		/* Inode is being renamed. */
 #define IN_SHLOCK       0x0020          /* File has shared lock. */
 #define	IN_EXLOCK	0x0040		/* File has exclusive lock. */
+#define	IN_LAZYMOD	0x0080		/* Modified, but don't write yet. */
 
 #define	i_devvp i_ump->um_devvp
 
diff --git a/sys/ufs/ufs/ufs_inode.c b/sys/ufs/ufs/ufs_inode.c
index 0b14a34cf4d..df5f2681911 100644
--- a/sys/ufs/ufs/ufs_inode.c
+++ b/sys/ufs/ufs/ufs_inode.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ufs_inode.c,v 1.38 2009/08/14 20:55:05 jasper Exp $	*/
+/*	$OpenBSD: ufs_inode.c,v 1.39 2014/03/19 04:17:33 guenther Exp $	*/
 /*	$NetBSD: ufs_inode.c,v 1.7 1996/05/11 18:27:52 mycroft Exp $	*/
 
 /*
@@ -139,10 +139,19 @@ ufs_reclaim(struct vnode *vp, struct proc *p)
 		vprint("ufs_reclaim: pushing active", vp);
 #endif
 
+	ip = VTOI(vp);
+
+	/*
+	 * Stop deferring timestamp writes
+	 */
+	if (ip->i_flag & IN_LAZYMOD) {
+		ip->i_flag |= IN_MODIFIED;
+		UFS_UPDATE(ip, 0);
+	}
+
 	/*
 	 * Remove the inode from its hash chain.
 	 */
-	ip = VTOI(vp);
 	ufs_ihashrem(ip);
 	/*
 	 * Purge old data structures associated with the inode.
diff --git a/sys/ufs/ufs/ufs_vnops.c b/sys/ufs/ufs/ufs_vnops.c
index daf7b6ab9aa..5f9fa643686 100644
--- a/sys/ufs/ufs/ufs_vnops.c
+++ b/sys/ufs/ufs/ufs_vnops.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ufs_vnops.c,v 1.112 2014/01/25 23:31:13 guenther Exp $	*/
+/*	$OpenBSD: ufs_vnops.c,v 1.113 2014/03/19 04:17:33 guenther Exp $	*/
 /*	$NetBSD: ufs_vnops.c,v 1.18 1996/05/11 18:28:04 mycroft Exp $	*/
 
 /*
@@ -131,7 +131,10 @@ ufs_itimes(struct vnode *vp)
 	}
 #endif
 
-	ip->i_flag |= IN_MODIFIED;
+	if ((vp->v_type == VBLK || vp->v_type == VCHR) && !DOINGSOFTDEP(vp))
+		ip->i_flag |= IN_LAZYMOD;
+	else
+		ip->i_flag |= IN_MODIFIED;
 
 	getnanotime(&ts);
 	if (ip->i_flag & IN_ACCESS) {