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@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.
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.