dm thin: prepare to support discard
authorJoe Thornber <ejt@redhat.com>
Wed, 28 Mar 2012 17:41:28 +0000 (18:41 +0100)
committerAlasdair G Kergon <agk@redhat.com>
Wed, 28 Mar 2012 17:41:28 +0000 (18:41 +0100)
commiteb2aa48d4eb7aee63cba201bf47641dad3e92250
tree3e160010319f6c4eb30770d07d6fb089955f5704
parent6efd6e83092cd4a7532270bc843de90bb93f6683
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>
drivers/md/dm-thin.c