[U-Boot] [PATCH v2 3/4] ubifs: Add generic fs support

Stephen Warren
2015-09-01T20:03:06Z

On 08/22/2015 11:04 AM, Hans de Goede wrote:
> Add generic fs support, so that commands like ls, load and test -e can be
> used on ubifs.

> @@ -530,6 +531,28 @@ int get_device_and_partition(const char *ifname, const char *dev_part_str,
> return 0;
> }
>
> +#ifdef CONFIG_CMD_UBIFS
> + /*
> + * Special-case ubi, ubi goes through a mtd, rathen then through
> + * a regular block device.
> + */
> + if (0 == strcmp(ifname, "ubi")) {
> + if (!ubifs_mounted) {
> + printf("UBIFS not mounted, use ubifsmount to mount volume first!\n");
> + return -1;
> + }
> +
> + *dev_desc = NULL;
> + memset(info, 0, sizeof(*info));
> + strcpy((char *)info->type, BOOT_PART_TYPE);
> + strcpy((char *)info->name, "UBI");
> +#ifdef CONFIG_PARTITION_UUIDS
> + info->uuid[0] = 0;
> +#endif
> + return 0;
> + }
> +#endif

We now have two paths through this function that can "Return" a NULL
dev_desc. This makes it impossible for sandbox and ubifs to successfully
co-exist in the same U-Boot binary, since the sandbox and ubifs fs probe
functions won't be able to tell if "hostfs" or "ubifs" was passed to
get_device_and_partition(). Perhaps there's no ubifs support in sandbox
right now, so there's no issue?

If this is an issue that needs to be solved now, I think the best
solution would be for the two special cases in
get_device_and_partition() to "return" a real dev_desc rather than NULL.
Since there's nothing meaningful to put there, how about returning a
hard-coded value that can then be checked in the fs probe functions to
make sure it matches:

get_device_and_partition():

if (hostfs) {
...
*dev_desc = &hostfs_fake_dev_desc;
...
return 0;
}
if (ubi) {
...
*dev_desc = &ubifs_fake_dev_desc;
...
return 0;
}

ubifs_set_blk_dev():

if (rbdd != &ubifs_fake_dev_desc)
return -1;
...
return 0;

... that said, I wonder if the ubifs special case in
get_device_and_partition() shouldn't actually perform the ubifs_mount()
call itself, based on the user-supplied parameters?