>>>>>>>> My new laptop uses /dev/nvme0n1 instead of /dev/sda which conflicts
>>>>>>>> with the script I use to manage about 12 similar laptops running
>>>>>>>> Gentoo. Is there a udev method for renaming the disk that will work
>>>>>>>> well with any USB disks that happen to also be attached?
>>>>>>>
>>>>>>> I'm not certain what you mean by that, but I would guess that you want
>>>>>>> the nvme disk to show up as /dev/sda, and the USB disk(s) to show up
>>>>>>> as /dev/sd[b-z].
>>>>>>>
>>>>>>> It is not possible to accomplish this using udev; the kernel owns the
>>>>>>> /dev/sdX device namespace, and will sequentially create devices nodes
>>>>>>> for SCSI-like block devices using that namespace. There is no way to
>>>>>>> change that using a udev rule.
>>>>>>
>>>>>>
>>>>>> Can I rename /dev/sda to /dev/sd[b-z] if it's attached via USB, and
>>>>>> then rename /dev/nvme0n1 to /dev/sda if /dev/nvme0n1 exists?
>>>>>>
>>>>>> Alternatively, can I rename /dev/sda to /dev/sd[b-z] if /dev/sda and
>>>>>> /dev/nvme0n1 exist, and then rename /dev/nvme0n1 to /dev/sda if
>>>>>> /dev/nvme0n1 exists?
>>>>>
>>>>> You might technically be able to do it, but I would guess it would
>>>>> cause some nasty race conditions between the kernel and udev. It's a
>>>>> bad idea.
>>>>
>>>>
>>>> Is it the conditionals that cause this to be a bad idea? Because I
>>>> believe udev has functionality designed to rename devices exactly like
>>>> this.
>>>
>>> udev doesn't provide any functionality to rename device nodes. You can
>>> adjust their permissions, and create symlinks, but there is no direct
>>> way to rename them.
>>
>>
>> I use stuff like this to rename my USB devices and it works perfectly:
>>
>> SUBSYSTEM=="net", ACTION=="add", ENV{ID_NET_NAME_PATH}=="enp0s20u2u1",
>> NAME="net0"
>>
>> Isn't this a true rename of the device node?
>
> Network devices don't have device nodes. They have interface names,
> which are a different concept entirely.
OK I'll take your advice and change the script to detect /dev/nvme0n1.
- Grant
