cramfs crc?

the cramfs_info structure contains a u32 crc field, but it is never used in the kernel. the mkcramfs tool calculates a crc on the whole fs image and then embeddeds this crc into the image file.

why is this never checked in the kernel? it could be recalculated at mount time and compared the the embedded crc. if a mismatch is detected, the mount could simply fail.

is there a reason this isn't done, or is it that nobody thought it would be useful?

thx,
jb