[RFD] diskfilter stale RAID member detection vs. lazy scanning

[Andrei Borzenkov]

I was looking at implementing detection of outdated RAID members.
Unfortunately it appears to be fundamentally incompatible with lazy
scanning as implemented currently by GRUB. We simply cannot stop
scanning for other copies of metadata once "enough" was seen. Because
any other disk may contain more actual copy which invalidates
everything seen up to this point.

So basically either we officially admit that GRUB is not able to detect
stale members or we drop lazy scanning.

Comments, ideas?