4 files changed, 27 insertions, 19 deletions
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index d1de1626a9d2..17cb2170e9d8 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -291,6 +291,12 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
 	unsigned short logical_block_size = queue_logical_block_size(q);
 	sector_t num_sectors;
 
+	/* Reject unsupported discard requests */
+	if ((rw & REQ_DISCARD) && !blk_queue_discard(q)) {
+		dec_count(io, region, -EOPNOTSUPP);
+		return;
+	}
+
 	/*
 	 * where->count may be zero if rw holds a flush and we need to
 	 * send a zero-sized flush.
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 699b5be68d31..678556b8ee4d 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -604,6 +604,15 @@ static void write_callback(unsigned long error, void *context)
 		return;
 	}
 
+	/*
+	 * If the bio is discard, return an error, but do not
+	 * degrade the array.
+	 */
+	if (bio->bi_rw & REQ_DISCARD) {
+		bio_endio(bio, -EOPNOTSUPP);
+		return;
+	}
+
 	for (i = 0; i < ms->nr_mirrors; i++)
 		if (test_bit(i, &error))
 			fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 944690bafd93..d892a05c84f4 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1439,8 +1439,6 @@ out:
 		full_bio->bi_end_io = pe->full_bio_end_io;
 		full_bio->bi_private = pe->full_bio_private;
 	}
-	free_pending_exception(pe);
-
 	increment_pending_exceptions_done_count();
 
 	up_write(&s->lock);
@@ -1457,6 +1455,8 @@ out:
 	}
 
 	retry_origin_bios(s, origin_bios);
+
+	free_pending_exception(pe);
 }
 
 static void commit_callback(void *context, int success)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 204a59fd872f..a87f0c42cb8b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2270,7 +2270,7 @@ int dm_setup_md_queue(struct mapped_device *md)
 	return 0;
 }
 
-static struct mapped_device *dm_find_md(dev_t dev)
+struct mapped_device *dm_get_md(dev_t dev)
 {
 	struct mapped_device *md;
 	unsigned minor = MINOR(dev);
@@ -2281,12 +2281,15 @@ static struct mapped_device *dm_find_md(dev_t dev)
 	spin_lock(&_minor_lock);
 
 	md = idr_find(&_minor_idr, minor);
-	if (md && (md == MINOR_ALLOCED ||
-		   (MINOR(disk_devt(dm_disk(md))) != minor) ||
-		   dm_deleting_md(md) ||
-		   test_bit(DMF_FREEING, &md->flags))) {
-		md = NULL;
-		goto out;
+	if (md) {
+		if ((md == MINOR_ALLOCED ||
+		     (MINOR(disk_devt(dm_disk(md))) != minor) ||
+		     dm_deleting_md(md) ||
+		     test_bit(DMF_FREEING, &md->flags))) {
+			md = NULL;
+			goto out;
+		}
+		dm_get(md);
 	}
 
 out:
@@ -2294,16 +2297,6 @@ out:
 
 	return md;
 }
-
-struct mapped_device *dm_get_md(dev_t dev)
-{
-	struct mapped_device *md = dm_find_md(dev);
-
-	if (md)
-		dm_get(md);
-
-	return md;
-}
 EXPORT_SYMBOL_GPL(dm_get_md);
 
 void *dm_get_mdptr(struct mapped_device *md)