<SNIP>
What I did:
- in /etc/fstab, I changed LABEL= to /dev/sda*
- I did rebuild the initramfs with that.
That still didn't do it.
Finally, I did this: from the grub2 boot menu, I edited the kernel line so that instead of reading ... root=LABEL=/, it read root=/dev/sda3, and it booted with zero issues.
There is, therefore, a bug in grub2? the handoff to systemd? where it does not handle LABEL correctly.
One more bit of information, which I added to the bug report: using e2label, I relabeled /boot and / to boot and root, and edited /etc/fstab and /etc/grub2.cfg to reflect that... and it booted with no trouble. I believe that a month ago, I neglected to edit grub2.cfg.
Note that /dev/sdd1 and /dev/sde1, which both have labels that begin with a leading slash, mounted correctly. This, to me, indicates the bug is with grub2's handling of LABEL=.
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