[tlug] strange , lseek64 vs blkgetsize64

[Mauro Sauco <mauro.sauco@example.com>]

folks, 

lseek64(tf, (off62_t)0, SEEK_END) doesn't return the true size of my 
device...(i'm trying to writing a driver for a memory device)  
blkgetsize64 does very well .... why ????

I'm confused, shouldn't iseek return the same for a block device too? 

Thanks,

//mauro//