crank up the statfs numbers to the max for those systems (e.g., OS X)
that pay attention to them.  cp on OS X will refuse to copy into
an nfs partition that appears to not have enough space.

Reference: /n/sources/patch/applied/nfsserver-more-free
Date: Sun Apr 16 03:56:29 CES 2006
Signed-off-by: geoff@collyer.net

--- /sys/src/cmd/9nfs/nfsserver.c	Sun Apr 16 03:55:29 2006
+++ /sys/src/cmd/9nfs/nfsserver.c	Sun Apr 16 03:55:26 2006
@@ -629,17 +629,22 @@
 nfsstatfs(int n, Rpccall *cmd, Rpccall *reply)
 {
 	uchar *dataptr = reply->results;
+	enum {
+		Xfersize = 2048,
+		Maxlong = (long)((1ULL<<31) - 1),
+		Maxfreeblks = Maxlong / Xfersize,
+	};
 
 	chat("statfs...");
 	showauth(&cmd->cred);
 	if(n != FHSIZE)
 		return garbage(reply, "bad count");
 	PLONG(NFS_OK);
-	PLONG(4096);	/* tsize */
-	PLONG(2048);	/* bsize */
-	PLONG(100000);	/* blocks */
-	PLONG(50000);	/* bfree */
-	PLONG(40000);	/* bavail */
+	PLONG(4096);		/* tsize (fs block size) */
+	PLONG(Xfersize);	/* bsize (optimal transfer size) */
+	PLONG(Maxfreeblks);	/* blocks in fs */
+	PLONG(Maxfreeblks);	/* bfree to root*/
+	PLONG(Maxfreeblks);	/* bavail (free to mortals) */
 	chat("OK\n");
 	/*conftime = 0;
 	readunixidmaps(config);*/