static int ubd_open_dev()

in drivers/ubd_kern.c [741:813]

• 65 lines of code
• 12 McCabe index (conditional complexity)

static int ubd_open_dev(struct ubd *ubd_dev)
{
	struct openflags flags;
	char **back_ptr;
	int err, create_cow, *create_ptr;
	int fd;

	ubd_dev->openflags = ubd_dev->boot_openflags;
	create_cow = 0;
	create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL;
	back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file;

	fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared,
				back_ptr, &ubd_dev->cow.bitmap_offset,
				&ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset,
				create_ptr);

	if((fd == -ENOENT) && create_cow){
		fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file,
					  ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE,
					  &ubd_dev->cow.bitmap_offset,
					  &ubd_dev->cow.bitmap_len,
					  &ubd_dev->cow.data_offset);
		if(fd >= 0){
			printk(KERN_INFO "Creating \"%s\" as COW file for "
			       "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file);
		}
	}

	if(fd < 0){
		printk("Failed to open '%s', errno = %d\n", ubd_dev->file,
		       -fd);
		return fd;
	}
	ubd_dev->fd = fd;

	if(ubd_dev->cow.file != NULL){
		blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long));

		err = -ENOMEM;
		ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len);
		if(ubd_dev->cow.bitmap == NULL){
			printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
			goto error;
		}
		flush_tlb_kernel_vm();

		err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap,
				      ubd_dev->cow.bitmap_offset,
				      ubd_dev->cow.bitmap_len);
		if(err < 0)
			goto error;

		flags = ubd_dev->openflags;
		flags.w = 0;
		err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL,
				    NULL, NULL, NULL, NULL);
		if(err < 0) goto error;
		ubd_dev->cow.fd = err;
	}
	if (ubd_dev->no_trim == 0) {
		ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE;
		ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE;
		blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
		blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
		blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue);
	}
	blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue);
	return 0;
 error:
	os_close_file(ubd_dev->fd);
	return err;
}