From 96b7da5f03e8fd1722cb66ef3cb7fcc02d703860 Mon Sep 17 00:00:00 2001
From: Nickolai Zeldovich <nickolai@csail.mit.edu>
Date: Fri, 24 Jun 2011 05:26:57 -0400
Subject: [PATCH] do not run past the end of the disk! [ cherry-picked
 de6075ff0978108daea1d658425bcb37663a98a0 ]

Conflicts:

	fs.c
---
 fs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs.c b/fs.c
index 15a4d35..7c6d904 100644
--- a/fs.c
+++ b/fs.c
@@ -61,7 +61,7 @@ balloc(uint dev)
   readsb(dev, &sb);
   for(b = 0; b < sb.size; b += BPB){
     bp = bread(dev, BBLOCK(b, sb.ninodes));
-    for(bi = 0; bi < BPB; bi++){
+    for(bi = 0; bi < BPB && bi < (sb.size - b); bi++){
       m = 1 << (bi % 8);
       if((bp->data[bi/8] & m) == 0){  // Is block free?
         bp->data[bi/8] |= m;  // Mark block in use on disk.