Merge tag 'dm-3.5-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm

Pull device-mapper discard fixes from Alasdair G Kergon:
  - avoid a crash in dm-raid1 when discards coincide with mirror
    recovery;
  - avoid discarding shared data that's still needed in dm-thin;
  - don't guarantee that discarded blocks will be wiped in dm-raid1.

* tag 'dm-3.5-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
  dm raid1: set discard_zeroes_data_unsupported
  dm thin: do not send discards to shared blocks
  dm raid1: fix crash with mirror recovery and discard

3 files changed, 11 insertions, 3 deletions

diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index d039de8322f0..b58b7a33914a 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1084,6 +1084,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
         ti->split_io = dm_rh_get_region_size(ms->rh);
         ti->num_flush_requests = 1;
         ti->num_discard_requests = 1;
+        ti->discard_zeroes_data_unsupported = 1;
 
         ms->kmirrord_wq = alloc_workqueue("kmirrord",
                                           WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
@@ -1214,7 +1215,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
          * We need to dec pending if this was a write.
          */
         if (rw == WRITE) {
-                if (!(bio->bi_rw & REQ_FLUSH))
+                if (!(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD)))
                         dm_rh_dec(ms->rh, map_context->ll);
                 return error;
         }
diff --git a/drivers/md/dm-region-hash.c b/drivers/md/dm-region-hash.c
index 7771ed212182..69732e03eb34 100644
--- a/drivers/md/dm-region-hash.c
+++ b/drivers/md/dm-region-hash.c
@@ -404,6 +404,9 @@ void dm_rh_mark_nosync(struct dm_region_hash *rh, struct bio *bio)
                 return;
         }
 
+        if (bio->bi_rw & REQ_DISCARD)
+                return;
+
         /* We must inform the log that the sync count has changed. */
         log->type->set_region_sync(log, region, 0);
 
@@ -524,7 +527,7 @@ void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios)
         struct bio *bio;
 
         for (bio = bios->head; bio; bio = bio->bi_next) {
-                if (bio->bi_rw & REQ_FLUSH)
+                if (bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))
                         continue;
                 rh_inc(rh, dm_rh_bio_to_region(rh, bio));
         }
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index ce59824fb414..68694da0d21d 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1245,7 +1245,10 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 
                         cell_release_singleton(cell, bio);
                         cell_release_singleton(cell2, bio);
-                        remap_and_issue(tc, bio, lookup_result.block);
+                        if ((!lookup_result.shared) && pool->pf.discard_passdown)
+                                remap_and_issue(tc, bio, lookup_result.block);
+                        else
+                                bio_endio(bio, 0);
                 }
                 break;
 
@@ -2628,6 +2631,7 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
         if (tc->pool->pf.discard_enabled) {
                 ti->discards_supported = 1;
                 ti->num_discard_requests = 1;
+                ti->discard_zeroes_data_unsupported = 1;
         }
 
         dm_put(pool_md);