diff -Nru /n/sources/plan9/sys/src/cmd/fossil/9fsys.c /sys/src/cmd/fossil/9fsys.c
--- /n/sources/plan9/sys/src/cmd/fossil/9fsys.c	Thu Jun 16 19:58:17 2011
+++ /sys/src/cmd/fossil/9fsys.c	Sat Dec  3 00:00:00 2011
@@ -1543,12 +1543,12 @@
 {
 	char *p, *host;
 	Fsys *fsys;
-	int noauth, noventi, noperm, rflag, wstatallow, noatimeupd;
+	int noauth, noventi, noperm, rflag, wstatallow, noatimeupd, nomtimeupd;
 	long ncache;
 	char *usage = "usage: fsys name open [-APVWr] [-c ncache]";
 
 	ncache = 1000;
-	noauth = noperm = wstatallow = noventi = noatimeupd = 0;
+	noauth = noperm = wstatallow = noventi = noatimeupd = nomtimeupd = 0;
 	rflag = OReadWrite;
 
 	ARGBEGIN{
@@ -1569,6 +1569,9 @@
 	case 'a':
 		noatimeupd = 1;
 		break;
+	case 'm':
+		nomtimeupd = 1;
+		break;
 	case 'c':
 		p = ARGF();
 		if(p == nil)
@@ -1629,6 +1632,7 @@
 	fsys->noperm = noperm;
 	fsys->wstatallow = wstatallow;
 	fsys->fs->noatimeupd = noatimeupd;
+	fsys->fs->nomtimeupd = nomtimeupd;
 	qunlock(&fsys->lock);
 	fsysPut(fsys);
 
diff -Nru /n/sources/plan9/sys/src/cmd/fossil/dat.h /sys/src/cmd/fossil/dat.h
--- /n/sources/plan9/sys/src/cmd/fossil/dat.h	Thu May 19 18:40:10 2011
+++ /sys/src/cmd/fossil/dat.h	Sat Dec  3 00:00:00 2011
@@ -75,6 +75,7 @@
 	Cache	*cache;		/* immutable */
 	int	mode;		/* immutable */
 	int	noatimeupd;	/* immutable */
+	int	nomtimeupd;	/* immutable */
 	int	blockSize;	/* immutable */
 	VtSession *z;		/* immutable */
 	Snap	*snap;		/* immutable */
diff -Nru /n/sources/plan9/sys/src/cmd/fossil/file.c /sys/src/cmd/fossil/file.c
--- /n/sources/plan9/sys/src/cmd/fossil/file.c	Thu Jun 16 00:00:00 2011
+++ /sys/src/cmd/fossil/file.c	Sat Dec  3 19:42:27 2011
@@ -471,7 +471,7 @@
 	dir->mtime = time(0L);
 	dir->mcount = 0;
 	dir->ctime = dir->mtime;
-	dir->atime = dir->mtime;
+	dir->atime = 0L;
 	dir->mode = mode;
 
 	ff->boff = fileMetaAlloc(f, dir, 0);
@@ -1685,7 +1685,7 @@
 static void
 fileWAccess(File* f, char *mid)
 {
-	if(f->mode == OReadOnly)
+	if(f->mode == OReadOnly || f->fs->nomtimeupd)
 		return;
 
 	fileMetaLock(f);
--- /n/sources/plan9/sys/man/8/fossilcons	Thu Jun 30 16:30:12 2011
+++ /sys/man/8/fossilcons	Sat Dec  3 00:00:00 2011
@@ -750,6 +750,9 @@
 do not update file access times;
 primarily to avoid wear on flash memories
 .TP
+.B -m
+do not update file modification times
+.TP
 .B -r
 open the file system read-only
 .TP