4 files changed, 30 insertions, 20 deletions

diff --git a/block.c b/block.c
index 6a1701a5ba..29f316e00c 100644
--- a/block.c
+++ b/block.c
@@ -45,6 +45,8 @@
 #define NO_THUNK_TYPE_SIZE
 #include "thunk.h"
 
+#include "cow.h"
+
 struct BlockDriverState {
     int fd; /* if -1, only COW mappings */
     int64_t total_sectors;
diff --git a/cow.h b/cow.h
new file mode 100644
index 0000000000..5b5f497ed3
--- /dev/null
+++ b/cow.h
@@ -0,0 +1,13 @@
+/* user mode linux compatible COW file */
+#define COW_MAGIC 0x4f4f4f4d  /* MOOO */
+#define COW_VERSION 2
+
+struct cow_header_v2 {
+    uint32_t magic;
+    uint32_t version;
+    char backing_file[1024];
+    int32_t mtime;
+    uint64_t size;
+    uint32_t sectorsize;
+};
+
diff --git a/qemu-mkcow.c b/qemu-mkcow.c
index 2cc6332e7f..7968bf9726 100644
--- a/qemu-mkcow.c
+++ b/qemu-mkcow.c
@@ -41,7 +41,7 @@
 #include <sys/stat.h>
 #include <netinet/in.h>
 
-#include "vl.h"
+#include "cow.h"
 
 #include "bswap.h"
 
@@ -101,13 +101,14 @@ void help(void)
 int main(int argc, char **argv)
 {
     const char *image_filename, *cow_filename;
-    int cow_fd, c, nb_args;
+    int cow_fd, c, nb_args, simple_image;
     int64_t image_size;
     
     image_filename = NULL;
     image_size = 0;
+    simple_image = 0;
     for(;;) {
-        c = getopt(argc, argv, "hf:");
+        c = getopt(argc, argv, "hf:s");
         if (c == -1)
             break;
         switch(c) {
@@ -117,6 +118,9 @@ int main(int argc, char **argv)
         case 'f':
             image_filename = optarg;
             break;
+        case 's':
+            simple_image = 1;
+            break;
         }
     }
     if (!image_filename)
@@ -131,12 +135,16 @@ int main(int argc, char **argv)
         image_size = (int64_t)atoi(argv[optind + 1]) * 2 * 1024;
     }
 
-    cow_fd = open(cow_filename, O_RDWR | O_CREAT | O_TRUNC, 0644);
+    cow_fd = open(cow_filename, O_RDWR | O_CREAT | O_TRUNC | O_LARGEFILE, 0644);
     if (!cow_fd < 0)
         return -1;
-    if (cow_create(cow_fd, image_filename, image_size) < 0) {
-        fprintf(stderr, "%s: error while formating\n", cow_filename);
-        exit(1);
+    if (simple_image) {
+        ftruncate64(cow_fd, image_size * 512);
+    } else {
+        if (cow_create(cow_fd, image_filename, image_size) < 0) {
+            fprintf(stderr, "%s: error while formating\n", cow_filename);
+            exit(1);
+        }
     }
     close(cow_fd);
     return 0;
diff --git a/vl.h b/vl.h
index c8c22ac397..35962d1985 100644
--- a/vl.h
+++ b/vl.h
@@ -58,19 +58,6 @@ void bdrv_get_geometry(BlockDriverState *bs, int64_t *nb_sectors_ptr);
 int bdrv_commit(BlockDriverState *bs);
 void bdrv_set_boot_sector(BlockDriverState *bs, const uint8_t *data, int size);
 
-/* user mode linux compatible COW file */
-#define COW_MAGIC 0x4f4f4f4d  /* MOOO */
-#define COW_VERSION 2
-
-struct cow_header_v2 {
-    uint32_t magic;
-    uint32_t version;
-    char backing_file[1024];
-    int32_t mtime;
-    uint64_t size;
-    uint32_t sectorsize;
-};
-
 /* vga.c */
 
 #define VGA_RAM_SIZE (4096 * 1024)