dm thin: prepare to support discard
This patch contains the ground work needed for dm-thin to support discard.
- Adds endio function that replaces shared_read_endio.
- Introduce an explicit 'quiesced' flag into the new_mapping structure.
Before, this was implicitly indicated by m->list being empty.
- The map_info->ptr remains constant for the duration of a bio's trip
through the thin target. Make it easier to reason about it.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1 file changed