Fix for a bug in halt
that could cause it not to wait until the changes were
written if there was an ongoing write at the time halt was
issued. 

Reference: /n/patches.lsub.org/patch/creepyhalt
Date: Tue Apr 17 10:59:19 CES 2012
Signed-off-by: nemo@lsub.org

--- /sys/src/cmd/creepy/9p.c	Wed Apr 11 18:41:53 2012
+++ /sys/src/cmd/creepy/9p.c	Tue Apr 17 10:45:14 2012
@@ -761,10 +761,6 @@
 			rpcworker9p(rpc, aux);
 		else
 			getworker(rpcworker9p, rpc, nil);
-		if(fs->halt){
-			warn("halted");
-			threadexitsall(nil);
-		}
 		rpc = nil;
 	}
 	putcli(cli);
--- /sys/src/cmd/creepy/cfg.c	Fri Mar 30 14:03:12 2012
+++ /sys/src/cmd/creepy/cfg.c	Tue Apr 17 10:45:27 2012
@@ -539,8 +539,8 @@
 static void
 chalt(int, char**)
 {
-	fssync();
 	fs->halt = 1;
+	fssync();
 }
 
 static void
--- /sys/src/cmd/creepy/fsys.c	Wed Apr 11 22:41:22 2012
+++ /sys/src/cmd/creepy/fsys.c	Tue Apr 17 10:54:07 2012
@@ -12,21 +12,6 @@
 	Nfsops,
 };
 
-
-
-BUG:
-issuing a halt calls a freeze and starts the write but does NOT
-wait for the write to complete before killing all threads, so data
-is lost because not everything is written.
-
-Check out that halt indeed waits for the write to complete!!
-
-freezing fs...
-freezing fs...
-fs frozen
-writing fs...
-creepy/9pix: /dev/sdC0/creepy: halted
-
 Fsys *fs;
 uvlong maxfsz;
 
@@ -606,6 +591,10 @@
 	fs->wtime = fstime(nsec());
 	xqunlock(&fs->fzlk);
 	dZprint("fs written (2*%ld refs %ld data)\n", nr, nb);
+	if(fs->halt){
+		warn("halted. exiting.");
+		threadexitsall(nil);
+	}
 }
 
 static void
--- /sys/src/cmd/creepy/ix.c	Wed Apr 11 18:42:56 2012
+++ /sys/src/cmd/creepy/ix.c	Tue Apr 17 10:45:37 2012
@@ -641,10 +641,6 @@
 			rpcworkerix(rpc->c, aux);
 		else
 			getworker(rpcworkerix, rpc->c, nil);
-		if(fs->halt){
-			fprint(2, "%s: halted\n", argv0);
-			threadexitsall(nil);
-		}
 	}
 	putcli(cli);
 	dPprint("%s exiting\n", threadgetname());