This fixes the "i_blocks went wrong when the disk filled up"

problem.

In ext3_new_block() we increment i_blocks early, so the
quota operation can be performed outside lock_super().
But if the block allocation ends up failing, we forget to
undo the allocation.  

This is not a serious bug, and probably does not warrant
an upgrade for production machines.  Its effects are:

1) errors are generated from e2fsck and

2) users could appear to be over quota when they really aren't.

The patch undoes the accounting operation if the allocation
ends up failing.

fs/ext3/balloc.c

@@ -542,6 +542,7 @@ int ext3_new_block (handle_t *handle, struct inode * inode,
 	int i, j, k, tmp, alloctmp;
 	int bitmap_nr;
 	int fatal = 0, err;
+	int performed_allocation = 0;
 	struct super_block * sb;
 	struct ext3_group_desc * gdp;
 	struct ext3_super_block * es;
@@ -644,8 +645,7 @@ int ext3_new_block (handle_t *handle, struct inode * inode,
 	}
 
 	/* No space left on the device */
-	unlock_super (sb);
-	return 0;
+	goto out;
 
 search_back:
 	/* 
@@ -694,6 +694,7 @@ int ext3_new_block (handle_t *handle, struct inode * inode,
 	J_ASSERT_BH(bh, !ext3_test_bit(j, bh->b_data));
 	BUFFER_TRACE(bh, "setting bitmap bit");
 	ext3_set_bit(j, bh->b_data);
+	performed_allocation = 1;
 
 #ifdef CONFIG_JBD_DEBUG
 	{
@@ -815,6 +816,11 @@ int ext3_new_block (handle_t *handle, struct inode * inode,
 		ext3_std_error(sb, fatal);
 	}
 	unlock_super (sb);
+	/*
+	 * Undo the block allocation
+	 */
+	if (!performed_allocation)
+		DQUOT_FREE_BLOCK(inode, 1);
 	return 0;
 	
 }