Add a sentinal value for devices that have been removed, but don't want
to reuse their index until a fsck has completed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Previously, device options had their superblock option field listed
separately, which was weird and easy to miss when defining options.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Create a sentinal value for "invalid device".
This is needed for removing devices that have stripes on them (force
removing, without evacuating); we need a sentinal value for the stripe
pointers to the device being removed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
