small bits from sources.  NB: this difference from sources remails
*surely* they don't mean to memset 4 bytes on 32-bit machines, and
8 bytes on 64-bit machines.  buf is a ptr.

/n/dump/2014/0320/sys/src/cmd/venti/srv/fixarenas.c:130,141 - srv/fixarenas.c:130,141
  	int i, j, k, n;
  
  	if(offset >= partend){
- 		memset(buf, 0xFB, sizeof buf);
+ 		memset(buf, 0xFB, len);
  		return buf;
  	}
  	
  	if(offset+len > partend){
- 		memset(buf, 0xFB, sizeof buf);
+ 		memset(buf, 0xFB, len);
  		len = partend - offset;
  	}
  

Reference: /n/atom/patch/applied/ventiemergency
Date: Thu Mar 20 15:45:02 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/venti/srv/arenas.c	Thu Mar 20 15:43:32 2014
+++ /sys/src/cmd/venti/srv/arenas.c	Thu Mar 20 15:43:32 2014
@@ -15,7 +15,8 @@
 
 enum
 {
-	AHashSize	= 512
+	AHashSize	= 512,
+	Emergency	= 0,		/* flag: performing emergency surgery */
 };
 
 static AHash	*ahash[AHashSize];
@@ -142,8 +143,11 @@
 	ap->narenas = amn.n;
 	ap->map = amn.map;
 	if(okamap(ap->map, ap->narenas, ap->arenabase, ap->size, "arena table") < 0){
-		freearenapart(ap, 0);
-		return nil;
+		if(!Emergency){
+			freearenapart(ap, 0);
+			return nil;
+		}
+		/* else keep on, for emergency use */
 	}
 
 	ap->arenas = MKNZ(Arena*, ap->narenas);
@@ -152,8 +156,14 @@
 		ap->arenas[i] = initarena(part, ap->map[i].start, ap->map[i].stop - ap->map[i].start, ap->blocksize);
 		if(ap->arenas[i] == nil){
 			seterr(ECorrupt, "%s: %r", ap->map[i].name);
-			freearenapart(ap, 1);
-			return nil;
+			if(!Emergency){
+				freearenapart(ap, 1);
+				return nil;
+			}else{
+				/* keep on, for emergency use */
+				ap->narenas = i;
+				break;
+			}
 		}
 		if(namecmp(ap->map[i].name, ap->arenas[i]->name) != 0){
 			seterr(ECorrupt, "arena name mismatches with expected name: %s vs. %s",
--- /sys/src/cmd/venti/copy.c	Thu Mar 20 15:43:32 2014
+++ /sys/src/cmd/venti/copy.c	Thu Mar 20 15:43:32 2014
@@ -37,13 +37,9 @@
 	b = (ScoreTree*)vb;
 
 	i = memcmp(a->score, b->score, VtScoreSize);
-	if(i == 0)
-		i = a->type - b->type;
-	if(i > 0)
-		i = 1;
-	if(i < 0)
-		i = -1;
-	return i;
+	if(i != 0)
+		return i;
+	return a->type - b->type;
 }
 
 static int