Three stable fixes (two in btree code used by DM thinp and one to

properly store flags in DM cache metadata's superblock).
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Merge tag 'dm-4.3-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "Three stable fixes (two in btree code used by DM thinp and one to
  properly store flags in DM cache metadata's superblock)"

* tag 'dm-4.3-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache: the CLEAN_SHUTDOWN flag was not being set
  dm btree: fix leak of bufio-backed block in btree_split_beneath error path
  dm btree remove: fix a bug when rebalancing nodes after removal

drivers/md/dm-cache-metadata.c

@@ -634,10 +634,10 @@ static int __commit_transaction(struct dm_cache_metadata *cmd,
 
 	disk_super = dm_block_data(sblock);
 
+	disk_super->flags = cpu_to_le32(cmd->flags);
 	if (mutator)
 		update_flags(disk_super, mutator);
 
-	disk_super->flags = cpu_to_le32(cmd->flags);
 	disk_super->mapping_root = cpu_to_le64(cmd->root);
 	disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 	disk_super->discard_root = cpu_to_le64(cmd->discard_root);

drivers/md/persistent-data/dm-btree-remove.c

@@ -301,11 +301,16 @@ static void redistribute3(struct dm_btree_info *info, struct btree_node *parent,
 {
 	int s;
 	uint32_t max_entries = le32_to_cpu(left->header.max_entries);
-	unsigned target = (nr_left + nr_center + nr_right) / 3;
-	BUG_ON(target > max_entries);
+	unsigned total = nr_left + nr_center + nr_right;
+	unsigned target_right = total / 3;
+	unsigned remainder = (target_right * 3) != total;
+	unsigned target_left = target_right + remainder;
+
+	BUG_ON(target_left > max_entries);
+	BUG_ON(target_right > max_entries);
 
 	if (nr_left < nr_right) {
-		s = nr_left - target;
+		s = nr_left - target_left;
 
 		if (s < 0 && nr_center < -s) {
 			/* not enough in central node */
@@ -316,10 +321,10 @@ static void redistribute3(struct dm_btree_info *info, struct btree_node *parent,
 		} else
 			shift(left, center, s);
 
-		shift(center, right, target - nr_right);
+		shift(center, right, target_right - nr_right);
 
 	} else {
-		s = target - nr_right;
+		s = target_right - nr_right;
 		if (s > 0 && nr_center < s) {
 			/* not enough in central node */
 			shift(center, right, nr_center);
@@ -329,7 +334,7 @@ static void redistribute3(struct dm_btree_info *info, struct btree_node *parent,
 		} else
 			shift(center, right, s);
 
-		shift(left, center, nr_left - target);
+		shift(left, center, nr_left - target_left);
 	}
 
 	*key_ptr(parent, c->index) = center->keys[0];

drivers/md/persistent-data/dm-btree.c

@@ -523,7 +523,7 @@ static int btree_split_beneath(struct shadow_spine *s, uint64_t key)
 
 	r = new_block(s->info, &right);
 	if (r < 0) {
-		/* FIXME: put left */
+		unlock_block(s->info, left);
 		return r;
 	}