In some specific situation we do not want to read the devices
before initialization.
Here it is integrity checking that will produce warning, because
the device is not yet initialized.
Used only in wipe function (here we must use direct-io anyway)
and expect the device is capable of direct-io.
This error code means invalid value, no point in repeating the whole sequence.
(If there is a situation that requires repeat, it should not return EINVAL.)
Initially cryptsetup expected underlying device that was, by definition,
always aligned to a sector size (and length was always multiple of sectors).
For the images in file, we can now access the image directly.
Expecting that the image is always aligned to the whole block is now false
(the last block in file image can be incomplete).
Moreover, we cannot easily detect underlying block device sector (block) size
(the storage stack can be complex with various RAID and loop block sizes),
so code uses systyem PAGE_SIZE in this situation (should be the safest way).
Unfortunately, PAGE_SIZE can be bigger (1MB) than device sector (4k) and
the blockwise functions then fails because the image in file is not
aligned to PAGE_SIZE multiple..
Fix it by checking that read/write for the last part of an image is
the exact requested size and not a full block.
(The problem is for example for an unaligned hidden Truecrypt header
on PPC64LE systems, where page size is 64k.)
With big page size and image in file this can actually happen.
The command works in this situation but the code will be quite
ineffective (due to blockwise handling).
This call is required for deferred removal of device.
Morever, if the system reports that udev is running, we should not
try to "fix" problems by creating or removing nodes directly through libdevmapper.
(Non-udev case should still work.)
this patches improves two areas:
1) it checks for keyslot areas overlaping each other
2) it checks if all keyslot areas fit in header area of device
(pre-data-offset area) or if it can fit file (detached header)
it's being loaded from. Those new checks are based on real data
found in header (offsets) rather than based on assumption calculated
from key length
