Re: [stable][PATCH < 2.6.19] Fix data corruption with dm-crypt over RAID5

[Piet Delaney <piet@bluelane.com>]

Christophe Saout wrote:

> Fix corruption issue with dm-crypt on top of software raid5. Cancelled
> readahead bio's that report no error, just have BIO_UPTODATE cleared
> were reported as successful reads to the higher layers (and leaving
> random content in the buffer cache). Already fixed in 2.6.19.
> 
> Signed-off-by: Christophe Saout <christophe@saout.de>
> 
> 
> --- linux-2.6.18.orig/drivers/md/dm-crypt.c   2006-09-20 05:42:06.000000000
> +0200
> +++ linux-2.6.18/drivers/md/dm-crypt.c        2006-12-02 03:03:36.000000000 +0100
> @@ -717,13 +717,15 @@
>  if (bio->bi_size)
>  return 1;
>  
> +     if (!bio_flagged(bio, BIO_UPTODATE) && !error)
> +             error = -EIO;
> +
>  bio_put(bio);
>  
>  /*
>  * successful reads are decrypted by the worker thread
>  */
> -     if ((bio_data_dir(bio) == READ)
> -         && bio_flagged(bio, BIO_UPTODATE)) {
> +     if (bio_data_dir(io->bio) == READ && !error) {
>  kcryptd_queue_io(io);

Why doesn't kcryptd_queue_io() check the return value from queue_work()?


    476 static void kcryptd_queue_io(struct crypt_io *io)
    477 {
    478         INIT_WORK(&io->work, kcryptd_do_work, io);
    479         queue_work(_kcryptd_workqueue, &io->work);
    480 }

-piet

>  return 0;
>  }