Merge tag 'dm-3.14-fixes-4' of git://git.kernel.org/pub/scm/linux/ker…

…nel/git/device-mapper/linux-dm

Pull device-mapper fixes form Mike Snitzer:
 "Two small fixes for the DM cache target:

   - fix corruption with >2TB fast device due to truncation bug
   - fix access beyond end of origin device due to a partial block"

* tag 'dm-3.14-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache: fix access beyond end of origin device
  dm cache: fix truncation bug when copying a block to/from >2TB fast device

drivers/md/dm-cache-target.c

@@ -979,12 +979,13 @@ static void issue_copy_real(struct dm_cache_migration *mg)
 	int r;
 	struct dm_io_region o_region, c_region;
 	struct cache *cache = mg->cache;
+	sector_t cblock = from_cblock(mg->cblock);
 
 	o_region.bdev = cache->origin_dev->bdev;
 	o_region.count = cache->sectors_per_block;
 
 	c_region.bdev = cache->cache_dev->bdev;
-	c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block;
+	c_region.sector = cblock * cache->sectors_per_block;
 	c_region.count = cache->sectors_per_block;
 
 	if (mg->writeback || mg->demote) {
@@ -2464,20 +2465,18 @@ static int cache_map(struct dm_target *ti, struct bio *bio)
 	bool discarded_block;
 	struct dm_bio_prison_cell *cell;
 	struct policy_result lookup_result;
-	struct per_bio_data *pb;
+	struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size);
 
-	if (from_oblock(block) > from_oblock(cache->origin_blocks)) {
+	if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) {
 		/*
 		 * This can only occur if the io goes to a partial block at
 		 * the end of the origin device.  We don't cache these.
 		 * Just remap to the origin and carry on.
 		 */
-		remap_to_origin_clear_discard(cache, bio, block);
+		remap_to_origin(cache, bio);
 		return DM_MAPIO_REMAPPED;
 	}
 
-	pb = init_per_bio_data(bio, pb_data_size);
-
 	if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) {
 		defer_bio(cache, bio);
 		return DM_MAPIO_SUBMITTED;