Add support for sparse ext4 image creation.

[android-x86/system-extras.git] / ext4_utils / ext4_utils.c

diff --git a/ext4_utils/ext4_utils.c b/ext4_utils/ext4_utils.c
index cd82827..f34985f 100644 (file)
--- a/ext4_utils/ext4_utils.c
+++ b/ext4_utils/ext4_utils.c
@@ -14,22 +14,12 @@
  * limitations under the License.
  */
 
-#include "ext4_utils.h"
-#include "output_file.h"
-#include "backed_block.h"
-#include "uuid.h"
-#include "allocate.h"
-#include "indirect.h"
-#include "extent.h"
-
-#include "ext4.h"
-#include "jbd2.h"
-
 #include <fcntl.h>
 #include <arpa/inet.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <string.h>
 
 #if defined(__linux__)
 #include <linux/fs.h>
@@ -37,6 +27,17 @@
 #include <sys/disk.h>
 #endif
 
+#include "ext4_utils.h"
+#include "output_file.h"
+#include "backed_block.h"
+#include "uuid.h"
+#include "allocate.h"
+#include "indirect.h"
+#include "extent.h"
+
+#include "ext4.h"
+#include "jbd2.h"
+
 int force = 0;
 struct fs_info info;
 struct fs_aux_info aux_info;
@@ -73,24 +74,36 @@ int ext4_bg_has_super_block(int bg)
 }
 
 /* Write the filesystem image to a file */
-void write_ext4_image(const char *filename, int gz)
+void write_ext4_image(const char *filename, int gz, int sparse)
 {
        int ret = 0;
-       struct output_file *out = open_output_file(filename, gz);
+       struct output_file *out = open_output_file(filename, gz, sparse);
        off_t off;
 
        if (!out)
                return;
 
-       write_data_block(out, 1024, (u8*)aux_info.sb, 1024);
+       /* The write_data* functions expect only block aligned calls.
+        * This is not an issue, except when we write out the super
+        * block on a system with a block size > 1K.  So, we need to
+        * deal with that here.
+        */
+       if (info.block_size > 1024) {
+               u8 buf[4096] = { 0 };   /* The larget supported ext4 block size */
+               memcpy(buf + 1024, (u8*)aux_info.sb, 1024);
+               write_data_block(out, 0, buf, info.block_size);
+
+       } else {
+               write_data_block(out, 1024, (u8*)aux_info.sb, 1024);
+       }
 
-       write_data_block(out, (aux_info.first_data_block + 1) * info.block_size,
+       write_data_block(out, (u64)(aux_info.first_data_block + 1) * info.block_size,
                         (u8*)aux_info.bg_desc,
                         aux_info.bg_desc_blocks * info.block_size);
 
        for_each_data_block(write_data_block, write_data_file, out);
 
-       write_data_block(out, info.len - 1, (u8*)"", 1);
+       pad_output_file(out, info.len);
 
        close_output_file(out);
 }