Hi All!
Need help!
I have tried to implement a block layered device driver which performs transparent encryption/decryption of data by interception WRITE/READ request ...
Now I have tried to resolve problem with incorrect data buffers content when more then one process performs I/O on block device like /dev/sda.
A part of driver is placed for review at :
http://codepad.org/IEqHY9er
Code:
static void __dua_bio_endio (
struct bio * iob
)
{
IOB_ARGS *iob_args = NULL;
struct bio *orig_bio = NULL;
iob_args = iob->bi_private;
if ( bio_data_dir(iob) == READ )
{
/* Restore has been replaced fields ... */
iob->bi_end_io = iob_args->bi_end_io;
iob->bi_private = iob_args->bi_private;
iob->bi_iter = iob_args->bi_iter;
/*
* In case of READ request - we getting original READ BIO,
* so we should decrypt data buffer right now at the place
*/
__dua_bio_enc_dec(iob, iob_args->bi_sector, DUDRV$K_DECRYPT);
/* Decrement reference count to original BIO */
bio_put(iob);
/* Call Complete I/O for original BIO */
bio_endio (iob);
}
...
}
As u can see data decrypted on the place.
