- two stable fixes for corruption seen in a snapshot of thinp metadata;

metadata snapshots aren't widely used but help provide a consistent
   view of the metadata associated with an active thin-pool.
 
 - a dm-cache fix for the 4.2 "default" policy switch from "mq" to "smq"
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Merge tag 'dm-4.2-fixes-5' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - two stable fixes for corruption seen in a snapshot of thinp metadata;
   metadata snapshots aren't widely used but help provide a consistent
   view of the metadata associated with an active thin-pool.

 - a dm-cache fix for the 4.2 "default" policy switch from "mq" to "smq"

* tag 'dm-4.2-fixes-5' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache policy smq: move 'dm-cache-default' module alias to SMQ
  dm btree: add ref counting ops for the leaves of top level btrees
  dm thin metadata: delete btrees when releasing metadata snapshot

drivers/md/dm-cache-policy-mq.c

@@ -1471,5 +1471,3 @@ module_exit(mq_exit);
 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("mq cache policy");
-
-MODULE_ALIAS("dm-cache-default");

drivers/md/dm-cache-policy-smq.c

@@ -1789,3 +1789,5 @@ module_exit(smq_exit);
 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("smq cache policy");
+
+MODULE_ALIAS("dm-cache-default");

drivers/md/dm-thin-metadata.c

@@ -1293,8 +1293,8 @@ static int __release_metadata_snap(struct dm_pool_metadata *pmd)
 		return r;
 
 	disk_super = dm_block_data(copy);
-	dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->data_mapping_root));
+	dm_btree_del(&pmd->info, le64_to_cpu(disk_super->data_mapping_root));
-	dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->device_details_root));
+	dm_btree_del(&pmd->details_info, le64_to_cpu(disk_super->device_details_root));
 	dm_sm_dec_block(pmd->metadata_sm, held_root);
 
 	return dm_tm_unlock(pmd->tm, copy);

drivers/md/persistent-data/dm-btree-internal.h

@@ -138,4 +138,10 @@ int lower_bound(struct btree_node *n, uint64_t key);
 
 extern struct dm_block_validator btree_node_validator;
 
+/*
+ * Value type for upper levels of multi-level btrees.
+ */
+extern void init_le64_type(struct dm_transaction_manager *tm,
+			   struct dm_btree_value_type *vt);
+
 #endif	/* DM_BTREE_INTERNAL_H */

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

@@ -544,14 +544,6 @@ static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
 	return r;
 }
 
-static struct dm_btree_value_type le64_type = {
-	.context = NULL,
-	.size = sizeof(__le64),
-	.inc = NULL,
-	.dec = NULL,
-	.equal = NULL
-};
-
 int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
 		    uint64_t *keys, dm_block_t *new_root)
 {
@@ -559,12 +551,14 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
 	int index = 0, r = 0;
 	struct shadow_spine spine;
 	struct btree_node *n;
+	struct dm_btree_value_type le64_vt;
 
+	init_le64_type(info->tm, &le64_vt);
 	init_shadow_spine(&spine, info);
 	for (level = 0; level < info->levels; level++) {
 		r = remove_raw(&spine, info,
 			       (level == last_level ?
-				&info->value_type : &le64_type),
+				&info->value_type : &le64_vt),
 			       root, keys[level], (unsigned *)&index);
 		if (r < 0)
 			break;
@@ -654,11 +648,13 @@ static int remove_one(struct dm_btree_info *info, dm_block_t root,
 	int index = 0, r = 0;
 	struct shadow_spine spine;
 	struct btree_node *n;
+	struct dm_btree_value_type le64_vt;
 	uint64_t k;
 
+	init_le64_type(info->tm, &le64_vt);
 	init_shadow_spine(&spine, info);
 	for (level = 0; level < last_level; level++) {
-		r = remove_raw(&spine, info, &le64_type,
+		r = remove_raw(&spine, info, &le64_vt,
 			       root, keys[level], (unsigned *) &index);
 		if (r < 0)
 			goto out;

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

@@ -249,3 +249,40 @@ int shadow_root(struct shadow_spine *s)
 {
 	return s->root;
 }
+
+static void le64_inc(void *context, const void *value_le)
+{
+	struct dm_transaction_manager *tm = context;
+	__le64 v_le;
+
+	memcpy(&v_le, value_le, sizeof(v_le));
+	dm_tm_inc(tm, le64_to_cpu(v_le));
+}
+
+static void le64_dec(void *context, const void *value_le)
+{
+	struct dm_transaction_manager *tm = context;
+	__le64 v_le;
+
+	memcpy(&v_le, value_le, sizeof(v_le));
+	dm_tm_dec(tm, le64_to_cpu(v_le));
+}
+
+static int le64_equal(void *context, const void *value1_le, const void *value2_le)
+{
+	__le64 v1_le, v2_le;
+
+	memcpy(&v1_le, value1_le, sizeof(v1_le));
+	memcpy(&v2_le, value2_le, sizeof(v2_le));
+	return v1_le == v2_le;
+}
+
+void init_le64_type(struct dm_transaction_manager *tm,
+		    struct dm_btree_value_type *vt)
+{
+	vt->context = tm;
+	vt->size = sizeof(__le64);
+	vt->inc = le64_inc;
+	vt->dec = le64_dec;
+	vt->equal = le64_equal;
+}

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

@@ -667,12 +667,7 @@ static int insert(struct dm_btree_info *info, dm_block_t root,
 	struct btree_node *n;
 	struct dm_btree_value_type le64_type;
 
-	le64_type.context = NULL;
+	init_le64_type(info->tm, &le64_type);
-	le64_type.size = sizeof(__le64);
-	le64_type.inc = NULL;
-	le64_type.dec = NULL;
-	le64_type.equal = NULL;
-
 	init_shadow_spine(&spine, info);
 
 	for (level = 0; level < (info->levels - 1); level++) {