file-win32: Support .bdrv_co_create

This adds the .bdrv_co_create driver callback to file-win32, which
enables image creation over QMP.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

block/file-win32.c

@@ -553,10 +553,40 @@ static int64_t raw_get_allocated_file_size(BlockDriverState *bs)
     return st.st_size;
 }
 
+static int raw_co_create(BlockdevCreateOptions *options, Error **errp)
+{
+    BlockdevCreateOptionsFile *file_opts;
+    int fd;
+
+    assert(options->driver == BLOCKDEV_DRIVER_FILE);
+    file_opts = &options->u.file;
+
+    if (file_opts->has_preallocation) {
+        error_setg(errp, "Preallocation is not supported on Windows");
+        return -EINVAL;
+    }
+    if (file_opts->has_nocow) {
+        error_setg(errp, "nocow is not supported on Windows");
+        return -EINVAL;
+    }
+
+    fd = qemu_open(file_opts->filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
+                   0644);
+    if (fd < 0) {
+        error_setg_errno(errp, errno, "Could not create file");
+        return -EIO;
+    }
+    set_sparse(fd);
+    ftruncate(fd, file_opts->size);
+    qemu_close(fd);
+
+    return 0;
+}
+
 static int coroutine_fn raw_co_create_opts(const char *filename, QemuOpts *opts,
                                            Error **errp)
 {
-    int fd;
+    BlockdevCreateOptions options;
     int64_t total_size = 0;
 
     strstart(filename, "file:", &filename);
@@ -565,19 +595,18 @@ static int coroutine_fn raw_co_create_opts(const char *filename, QemuOpts *opts,
     total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
                           BDRV_SECTOR_SIZE);
 
-    fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
+    options = (BlockdevCreateOptions) {
-                   0644);
+        .driver     = BLOCKDEV_DRIVER_FILE,
-    if (fd < 0) {
+        .u.file     = {
-        error_setg_errno(errp, errno, "Could not create file");
+            .filename           = (char *) filename,
-        return -EIO;
+            .size               = total_size,
-    }
+            .has_preallocation  = false,
-    set_sparse(fd);
+            .has_nocow          = false,
-    ftruncate(fd, total_size);
+        },
-    qemu_close(fd);
+    };
-    return 0;
+    return raw_co_create(&options, errp);
 }
 
-
 static QemuOptsList raw_create_opts = {
     .name = "raw-create-opts",
     .head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),