On 09/03/2010 12:29 PM, Tejun Heo wrote:
> +++ b/drivers/md/dm-crypt.c
> @@ -1278,7 +1278,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
> struct dm_crypt_io *io;
> struct crypt_config *cc;
>
> - if (unlikely(bio_empty_barrier(bio))) {
> + if (bio->bi_rw & REQ_FLUSH) {
> cc = ti->private;
> bio->bi_bdev = cc->dev->bdev;
> return DM_MAPIO_REMAPPED;
...
> +++ b/drivers/md/dm.c
> @@ -1400,14 +1391,22 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
> ci.io->md = md;
> spin_lock_init(&ci.io->endio_lock);
> ci.sector = bio->bi_sector;
> - ci.sector_count = bio_sectors(bio);
> - if (unlikely(bio_empty_barrier(bio)))
> + if (!(bio->bi_rw & REQ_FLUSH))
> + ci.sector_count = bio_sectors(bio);
> + else {
> + /* all FLUSH bio's reaching here should be empty */
> + WARN_ON_ONCE(bio_has_data(bio));
> ci.sector_count = 1;
> + }
I would add BUG_ON(bio_has_data(bio)) either to dm-crypt target or directly to DM core
in this path.
Note that empty barrier request bypass encryption layer now in dm-crypt, so if some bio
with data payload reach it after the change, it causes data corruption
(moreover plain data reach the disk directly).
Milan
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