file.h

@@ -21,7 +21,7 @@ struct inode {
   short minor;
   short nlink;
   uint size;
-  uint addrs[NDIRECT+3];
+  uint addrs[NDIRECT+1];
 };
 #define I_BUSY 0x1
 #define I_VALID 0x2

fs.c

@@ -356,25 +356,18 @@ iunlockput(struct inode *ip)
 static uint
 bmap(struct inode *ip, uint bn)
 {
-  uint addr, *a, i;
+  uint addr, *a;
   struct buf *bp;
 
-  // We use 10 direct, two indirect and one double indirect pointer
   if(bn < NDIRECT){
-    // If block number is less than direct pointers available
-    // allocate a disk block if not allocated/available
-    // then return the address of the block
     if((addr = ip->addrs[bn]) == 0)
       ip->addrs[bn] = addr = balloc(ip->dev);
     return addr;
   }
-  // The block number does not fall in the first 10 direct blocks
-  // Substract the number from the passed block number
   bn -= NDIRECT;
 
   if(bn < NINDIRECT){
     // Load indirect block, allocating if necessary.
-    // This is the first indirect block range
     if((addr = ip->addrs[NDIRECT]) == 0)
       ip->addrs[NDIRECT] = addr = balloc(ip->dev);
     bp = bread(ip->dev, addr);
@@ -385,39 +378,6 @@ bmap(struct inode *ip, uint bn)
     }
     brelse(bp);
     return addr;
-  } else if(bn < NINDIRECT * 2){
-    bn -= NINDIRECT;
-    // Load indirect block, allocating if necessary.
-    // This is the second indirect block range
-    if((addr = ip->addrs[NDIRECT+1]) == 0)
-      ip->addrs[NDIRECT+1] = addr = balloc(ip->dev);
-    bp = bread(ip->dev, addr);
-    a = (uint*)bp->data;
-    if((addr = a[bn]) == 0){
-      a[bn] = addr = balloc(ip->dev);
-      log_write(bp);
-    }
-    brelse(bp);
-    return addr;
-  } else {
-    // We are now in the double indirect block range
-    bn -= NINDIRECT * 2;
-    // Load indirect block, allocating if necessary.
-    if((addr = ip->addrs[NDIRECT+2]) == 0)
-      ip->addrs[NDIRECT+2] = addr = balloc(ip->dev);
-    bp = bread(ip->dev, addr);
-    a = (uint*)bp->data;
-    // This last double indirect block should contain addresses to
-    // other blocks and not data. Fig 6.4 of xv6 booklet
-    for (i = 0; i < BSIZE/4; i++){
-      if((addr = a[i]) == 0){
-        a[bn] = addr = balloc(ip->dev);
-        log_write(bp);
-        break;
-      }
-    }
-    brelse(bp);
-    return addr;
   }
 
   panic("bmap: out of range");
@@ -441,7 +401,7 @@ itrunc(struct inode *ip)
       ip->addrs[i] = 0;
     }
   }
-
+  
   if(ip->addrs[NDIRECT]){
     bp = bread(ip->dev, ip->addrs[NDIRECT]);
     a = (uint*)bp->data;

fs.h

@@ -19,9 +19,9 @@ struct superblock {
   uint nlog;         // Number of log blocks
 };
 
-#define NDIRECT 10
+#define NDIRECT 12
 #define NINDIRECT (BSIZE / sizeof(uint))
-#define MAXFILE (NDIRECT + 2 * NINDIRECT + NINDIRECT * NINDIRECT)
+#define MAXFILE (NDIRECT + NINDIRECT)
 
 // On-disk inode structure
 struct dinode {
@@ -30,7 +30,7 @@ struct dinode {
   short minor;          // Minor device number (T_DEV only)
   short nlink;          // Number of links to inode in file system
   uint size;            // Size of file (bytes)
-  uint addrs[NDIRECT+3];   // Data block addresses
+  uint addrs[NDIRECT+1];   // Data block addresses
 };
 
 // Inodes per block.