__bread - reads a specified block and returns the bh
"struct buffer_head * __bread(struct block_device * " "bdev" ", sector_t " "block" ", unsigned " "size" ");"
bdev
the block_device to read fromblocknumber of block size size (in bytes) to read
Reads a specified block, and returns buffer head that contains it. It returns NULL if the block was unreadable.
