Enable writing after the 2G boundary

This patch fixes a bug in readwrite.c which truncated the 'from' field
in nbd requests.  It was casting them down from an off64_t to an int.

src/client.c

@@ -136,7 +136,6 @@ void write_not_zeroes(struct client* client, uint64_t from, int len)
 				 */
 				if (zerobuffer[0] != 0 || 
 				    memcmp(zerobuffer, zerobuffer + 1, blockrun - 1)) {
-					debug("non-zero, writing from=%ld, blockrun=%d", from, blockrun);
 					memcpy(client->mapped+from, zerobuffer, blockrun);
 					bitset_set_range(map, from, blockrun);
 					server_dirty(client->serve, from, blockrun);
@@ -147,9 +146,7 @@ void write_not_zeroes(struct client* client, uint64_t from, int len)
 					 * sparseness as possible.
 					 */
 				}
-				else {
+
-					debug("all zero, skip write");
-				}
 				len  -= blockrun;
 				run  -= blockrun;
 				from += blockrun;
@@ -164,6 +161,7 @@ int fd_read_request( int fd, struct nbd_request_raw *out_request)
 	return readloop(fd, out_request, sizeof(struct nbd_request_raw));
 }
 
+
 /* Returns 1 if *request was filled with a valid request which we should
  * try to honour. 0 otherwise. */
 int client_read_request( struct client * client , struct nbd_request *out_request, int * disconnected )
@@ -318,7 +316,7 @@ int client_request_needs_reply( struct client * client,
 				"after an entrust message.");
 		/* check it's not out of range */
 		if ( request.from+request.len > client->serve->size) {
-			debug("request read %ld+%d out of range", 
+			debug("request read %llx+%ld out of range", 
 			  request.from, 
 			  request.len
 			);
@@ -495,7 +493,7 @@ void* client_serve(void* client_uncast)
 			NULL, 
 			(void**) &client->mapped
 		),
-		"Couldn't open/mmap file %s", client->serve->filename
+		"Couldn't open/mmap file %s: %s", client->serve->filename, strerror( errno )
 	);
 	debug("client: sending hello");
 	client_send_hello(client);

src/ioutil.c

@@ -55,6 +55,9 @@ struct bitset_mapping* build_allocation_map(int fd, uint64_t size, int resolutio
 		);
 	}
 	
+	/* This is pointlessly verbose for real discs, it's here as a
+	 * reference for pulling data out of the allocation map */
+	if ( 0 ) {
 		for (i=0; i<(size/resolution); i++) {
 			debug("map[%d] = %d%d%d%d%d%d%d%d",
 					i,
@@ -68,6 +71,7 @@ struct bitset_mapping* build_allocation_map(int fd, uint64_t size, int resolutio
 					(allocation_map->bits[i] & 128) == 128
 			     );
 		}
+	}
 	
 	
 	free(fiemap);

src/readwrite.c

@@ -56,7 +56,7 @@ fail:
 	return 0;
 }
 
-void fill_request(struct nbd_request *request, int type, int from, int len)
+void fill_request(struct nbd_request *request, int type, off64_t from, int len)
 {
 	request->magic  = htobe32(REQUEST_MAGIC);
 	request->type   = htobe32(type);

tests/acceptance/environment.rb

@@ -79,6 +79,10 @@ class Environment
   end
 
 
+  def truncate1( size )
+    system "truncate -s #{size} #{@filename1}"
+  end
+
 
   def listening_ports
     `netstat -ltn`.

tests/acceptance/test_happy_path.rb

@@ -81,4 +81,15 @@ class TestHappyPath < Test::Unit::TestCase
     assert @env.status2['has_control'], "destination didn't take control"
   end
 
+
+  def test_write_to_high_block
+    # Create a large file, then try to write to somewhere after the 2G boundary
+    @env.truncate1 "4G"
+    @env.serve1
+
+    @env.nbd1.write( 2**31+2**29, "12345678" )
+    sleep(1)
+    assert_equal "12345678", @env.nbd1.read( 2**31+2**29, 8 )
+  end
+
 end

tests/unit/check_nbdtypes.c

@@ -182,6 +182,24 @@ START_TEST(test_reply_handle)
 END_TEST
 
 
+START_TEST( test_convert_from )
+{
+	/* Check that we can correctly pull numbers out of an
+	 * nbd_request_raw */
+	struct nbd_request_raw request_raw;
+	struct nbd_request     request;
+	char readbuf[] = {0x80, 0, 0, 0, 0, 0, 0, 0};
+
+	memcpy( &request_raw.from, readbuf, 8 );
+
+	nbd_r2h_request( &request_raw, &request );
+
+	uint64_t target = 1;
+	target <<= 63;
+	fail_unless( target == request.from, "from was wrong" );
+}	
+END_TEST
+
 Suite *nbdtypes_suite(void) 
 {
 	Suite *s = suite_create( "nbdtypes" );
@@ -197,6 +215,7 @@ Suite *nbdtypes_suite(void)
 	tcase_add_test( tc_request, test_request_handle );
 	tcase_add_test( tc_request, test_request_from );
 	tcase_add_test( tc_request, test_request_len );
+	tcase_add_test( tc_request, test_convert_from );
 	tcase_add_test( tc_reply, test_reply_magic );
 	tcase_add_test( tc_reply, test_reply_error );
 	tcase_add_test( tc_reply, test_reply_handle );