The error correction can fix even problem with root hash.
For now, always return fail if initial check of root hash failed.
FIXME: The FEC verify code need to be rewritten to repair only
blocks where hash is wrong and the re-check hash after recovery,
inclkuding root hash.
Now we do not check hash after FEC recovery. The Reed-Solomon
decoder can then "repair" code wrongly if parity is too damaged.
For now, the information about FEC repaired errors is only
advisory, it does not mean device is fully repaireable.
If FEC was enabled, the error for bad root hash was replaced
by error correction (datga were ok, only root hash was wrong).
Do not run recovery test if root hash is incorrect.
Other APIs use the root hash in place of keys when using verity
devices, so do the same for crypt_volume_key_get to allow users
to retrieve the root hash of an active verity device.
Use it in veritysetup status to print the root hash.
[Patch slightly modified by Milan Broz]
This includes crypto, loopaes, tcrypt handling code I have written myself
and verity code written originally by Mikulas Patocka and modified by me,
copyright by Red Hat.
Other part of library have to stay GPLv2+ only for now
(no agreement from all authors).
Allocate loop device late (only when real block device needed).
Rework underlying device/file access functions.
Move all device (and ioctl) access to utils_device.c.
Allows using file where appropriate without allocation loop device.
