fs/udf/inode.c: fix a check after use

@@ -1948,28 +1948,30 @@
 	udf_release_data(obh);
 	return (elen >> 30);
 }
 
 int8_t inode_bmap(struct inode *inode, int block, kernel_lb_addr *bloc, uint32_t *extoffset,
 	kernel_lb_addr *eloc, uint32_t *elen, uint32_t *offset, struct buffer_head **bh)
 {
-	uint64_t lbcount = 0, bcount = (uint64_t)block << inode->i_sb->s_blocksize_bits;
+	uint64_t lbcount = 0, bcount;
 	int8_t etype;
 
 	if (block < 0)
 	{
 		printk(KERN_ERR "udf: inode_bmap: block < 0\n");
 		return -1;
 	}
 	if (!inode)
 	{
 		printk(KERN_ERR "udf: inode_bmap: NULL inode\n");
 		return -1;
 	}
 
+	bcount = (uint64_t)block << inode->i_sb->s_blocksize_bits;
+
 	*extoffset = 0;
 	*elen = 0;
 	*bloc = UDF_I_LOCATION(inode);
 
 	do
 	{
 		if ((etype = udf_next_aext(inode, bloc, extoffset, eloc, elen, bh, 1)) == -1)