Re: No /dev/root with devtmpfs?

From: Kay Sievers
Date: Mon Feb 06 2012 - 14:45:42 EST

On Mon, Feb 6, 2012 at 12:18, Kirill Smelkov <kirr@xxxxxxxxxx> wrote:
> Recently I've reworked my system not to use udev, but use devtmpfs
> instead and discovered there is no /dev/root symlink in devtmpfs case.
> My setup uses /dev/root early to know what is the boot device and then
> do some operations on it like checksumming, etc...
> Now when /dev/root is gone the best workaround I could come up with is
> to  grep /proc/partitions for '[hs]d[a-z]1' Âbut it's ugly and will
> break when there are several block devices attached.
> Is it somehow possible to add /dev/root to devtmpfs?

No, devtmpfs has no business in knowing anything about the rootfs or
who mounted what ans where. I can not create such links.

The entire concept of /dev/root is flawed anyway, and nothing should
really depend on that.

Modern filesystems will not offer a direct relation to a single block
device, they allocate an superblock which has a major == 0, so there
can be by definition never such a link. Better get rid of all uses of
/dev/root, it will just fail in the future.

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