--- /n/sources/plan9/sys/src/cmd/fossil/cache.c	Mon Nov 14 16:09:31 2016
+++ /sys/src/cmd/fossil/cache.c	Tue Oct  6 12:00:00 2020
@@ -144,14 +144,13 @@
  * Allocate the memory cache.
  */
 Cache *
-cacheAlloc(Disk *disk, VtConn *z, ulong nblocks, int mode)
+cacheAlloc(Disk *disk, VtConn *z, uvlong nblocks, int mode)
 {
-	int i;
+	uvlong i, nbl;
 	Cache *c;
 	Block *b;
 	BList *bl;
 	u8int *p;
-	int nbl;
 
 	c = vtmallocz(sizeof(Cache));
 
@@ -283,7 +282,6 @@
 {
 	u32int size, now;
 	int i, k, refed;
-	static uchar zero[VtScoreSize];
 	Block *b;
 
 	size = c->size;
@@ -305,7 +303,7 @@
 	refed = 0;
 	for(i = 0; i < c->nblocks; i++){
 		b = &c->blocks[i];
-		if(b->data != &c->mem[i * size])
+		if(b->data != &c->mem[(uintptr)i * size])
 			sysfatal("mis-blocked at %d", i);
 		if(b->ref && b->heap == BadHeap){
 			refed++;
@@ -851,7 +849,6 @@
 	*used = nused;
 	*total = fl->end;
 	qunlock(&fl->lk);
-	return;
 }
 
 static FreeList *
@@ -1209,7 +1206,7 @@
 			fprint(2, "%s: %d:%x:%d iostate is %d in blockWrite\n",
 				argv0, bb->part, bb->addr, bb->l.type, bb->iostate);
 			/* probably BioWriting if it happens? */
-			if(bb->iostate == BioClean){
+			if(bb->iostate == BioClean) {
 				blockPut(bb);
 				goto ignblock;
 			}
--- /n/sources/plan9/sys/src/cmd/fossil/dat.h	Mon Nov 14 16:09:31 2016
+++ /sys/src/cmd/fossil/dat.h	Tue Oct  6 12:00:00 2020
@@ -59,6 +59,11 @@
 	UserTag = 32,		/* all other tags should be >= UserTag */
 };
 
+/*
+ * use of u32int for block numbers here limits fossil write buffer partitions
+ * to 32TB.  using wider integers will invalidate any existing superblocks.
+ * see also superPack and superUnpack.
+ */
 struct Super {
 	u16int version;
 	u32int epochLow;
@@ -235,7 +240,7 @@
 	QLock	lk;
 
 	int 	part;
-	u32int	addr;
+	u32int	addr;			/* should be uvlong */
 	uchar	score[VtScoreSize];	/* score */
 	Label	l;
 
--- /n/sources/plan9/sys/src/cmd/fossil/file.c	Wed Apr  7 19:24:25 2021
+++ /sys/src/cmd/fossil/file.c	Wed Apr 28 12:00:00 2021
@@ -1569,7 +1569,7 @@
 		b = sourceBlock(ms, bo, OReadWrite);
 		if(b == nil)
 			goto Err;
-		sourceSetSize(ms, (nb+1)*ms->dsize);
+		sourceSetSize(ms, ((uvlong)nb+1)*ms->dsize);
 		mbInit(&mb, b->data, ms->dsize, ms->dsize/BytesPerEntry);
 	}
 
--- /n/sources/plan9/sys/src/cmd/fossil/fns.h	Mon Nov 14 16:09:31 2016
+++ /sys/src/cmd/fossil/fns.h	Tue Oct  6 12:00:00 2020
@@ -18,7 +18,7 @@
 void	sourceUnlock(Source*);
 
 Block*	cacheAllocBlock(Cache*, int, u32int, u32int, u32int);
-Cache*	cacheAlloc(Disk*, VtConn*, ulong, int);
+Cache*	cacheAlloc(Disk*, VtConn*, uvlong, int);
 void	cacheCountUsed(Cache*, u32int, u32int*, u32int*, u32int*);
 int	cacheDirty(Cache*);
 void	cacheFlush(Cache*, int);
--- /n/sources/plan9/sys/src/cmd/fossil/fs.c	Mon Nov 14 16:09:31 2016
+++ /sys/src/cmd/fossil/fs.c	Tue Oct  6 12:00:00 2020
@@ -8,7 +8,7 @@
 static void snapClose(Snap*);
 
 Fs *
-fsOpen(char *file, VtConn *z, long ncache, int mode)
+fsOpen(char *file, VtConn *z, vlong ncache, int mode)
 {
 	int fd, m;
 	uchar oscore[VtScoreSize];
@@ -432,7 +432,6 @@
 		return 0;
 	}
 
-	if(0) fprint(2, "%s: snapshot root from %d to %d\n", argv0, oldaddr, b->addr);
 	entryPack(&e, b->data, 1);
 	blockDirty(b);
 
@@ -451,6 +450,8 @@
 	super.active = b->addr;
 	if(doarchive)
 		super.next = oldaddr;
+	if(0) fprint(2, "%s: snapshot root from %d to %d\n",
+		argv0, oldaddr, b->addr);
 
 	/*
 	 * Record that the new super.active can't get written out until
--- /n/sources/plan9/sys/src/cmd/fossil/fs.h	Mon Nov 14 16:09:31 2016
+++ /sys/src/cmd/fossil/fs.h	Tue Oct  6 12:00:00 2020
@@ -26,7 +26,7 @@
 int	fsEpochLow(Fs*, u32int);
 File	*fsGetRoot(Fs*);
 int	fsHalt(Fs*);
-Fs	*fsOpen(char*, VtConn*, long, int);
+Fs	*fsOpen(char*, VtConn*, vlong, int);
 int	fsRedial(Fs*, char*);
 void	fsSnapshotCleanup(Fs*, u32int);
 int	fsSnapshot(Fs*, char*, char*, int);