[U-Boot] [PATCH] fs: make it possible to read the filesystem UUID

[Christian Gmeiner]

Hi


2014-11-03 22:00 GMT+01:00 Stephen Warren <swarren at wwwdotorg.org>:
> On 10/31/2014 09:08 AM, Christian Gmeiner wrote:
>>
>> Some filesystems have a UUID stored in its superblock. To
>> allow using root=UUID=... for the kernel command line we
>> need a way to read-out the filesystem UUID.
>>
>> Hit any key to stop autoboot:  0
>> => fsuuid
>> fsuuid - Look up a filesystem UUID
>>
>> Usage:
>> fsuuid <interface> <dev>:<part>
>>      - print filesystem UUID
>> fsuuid <interface> <dev>:<part> <varname>
>>      - set environment variable to filesystem UUID
>>
>> => fsuuid mmc 0:1
>> d9f9fc05-45ae-4a36-a616-fccce0e4f887
>> => fsuuid mmc 0:2
>> eb3db83c-7b28-499f-95ce-9e0bb21cda81
>> => fsuuid mmc 0:1 uuid1
>> => fsuuid mmc 0:2 uuid2
>> => printenv uuid1
>> uuid1=d9f9fc05-45ae-4a36-a616-fccce0e4f887
>> => printenv uuid2
>> uuid2=eb3db83c-7b28-499f-95ce-9e0bb21cda81
>> =>
>
>
> Acked-by: Stephen Warren <swarren at nvidia.com>
>
> It'd be nice if you could implement fat_uuid() too, and plumb that in. That
> could be a separate commit though I suppose.
>
> IIRC, the kernel accepts the format NNNNNNNN-MM where NNNNNNNN is the 32-bit
> FAT disk ID (I don't recall the exact correct term) in 0-filled hex and MM
> is the partition number in 0-filled decimal.
>

Lets see if I can find the motivation to look into fat :)

>> diff --git a/fs/fs.c b/fs/fs.c
>
>
>> +int fs_uuid(char *uuid_str)
>> +{
>> +       struct fstype_info *info = fs_get_info(fs_type);
>> +       int ret = -ENOSYS;
>> +
>> +       if (info->uuid)
>> +               ret = info->uuid(uuid_str);
>> +
>> +       return ret;
>> +}
>
>
> Actually, that might be better as:
>
> return info->uuid(uuid_str);
>
> To make that work, you'd need to implement a fs_uuid_unsuported() function
> and fill it in for all the fs types in fstypes[]. That would be more
> consistent with the way other optional functionality works in this file.

I will do it that way - looks more consistent.

greets
--
Christian Gmeiner, MSc

https://soundcloud.com/christian-gmeiner