The kernel is yet unable to use the linux extended partition (type 0x85). The
linux extended partition is just a dos extended partition with a different
identifier, as not to confuse dos.
Implementing the use of the linux extended partition requires the partition
type to be known, and a check for its presence.
Fix: Following is a diff of the original to a patched /sys/kern/subr_diskmbr.c:
I'll commit something close to this once it's made it
through a kernel build. :-)
I seem to remember either bde or msmith being unhappy with the change for
some reason. Shame on me for not copying the message to the audit trail.
Anyway, I can't follow it up now, so throw it open to the peanut gallery. :-)
The patch is too old and doesn't apply (the file doesn't exist anymore).
In any case I haven't heard of problems mounting modern ext2/3/4.