[PATCH v2 07/16] btrfs: remove btrfs_disk_cache_state

@@ -2448,8 +2448,7 @@ static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
 
 static int read_one_block_group(struct btrfs_fs_info *info,
 				struct btrfs_block_group_item_v2 *bgi,
-				const struct btrfs_key *key,
-				bool need_clear)
+				const struct btrfs_key *key)
 {
 	struct btrfs_block_group *cache;
 	const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS);

@@ -2475,20 +2474,6 @@ static int read_one_block_group(struct btrfs_fs_info *info,
 
 	btrfs_set_free_space_tree_thresholds(cache);
 
-	if (need_clear) {
-		/*
-		 * When we mount with old space cache, we need to
-		 * set BTRFS_DC_CLEAR and set dirty flag.
-		 *
-		 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
-		 *    truncate the old free space cache inode and
-		 *    setup a new one.
-		 * b) Setting 'dirty flag' makes sure that we flush
-		 *    the new space cache info onto disk.
-		 */
-		if (btrfs_test_opt(info, SPACE_CACHE))
-			cache->disk_cache_state = BTRFS_DC_CLEAR;
-	}
 	if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
 	    (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
 			btrfs_err(info,

@@ -2629,8 +2614,6 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
 	struct btrfs_block_group *cache;
 	struct btrfs_space_info *space_info;
 	struct btrfs_key key;
-	bool need_clear = false;
-	u64 cache_gen;
 
 	/*
 	 * Either no extent root (with ibadroots rescue option) or we have

@@ -2651,13 +2634,6 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
 	if (!path)
 		return -ENOMEM;
 
-	cache_gen = btrfs_super_cache_generation(info->super_copy);
-	if (btrfs_test_opt(info, SPACE_CACHE) &&
-	    btrfs_super_generation(info->super_copy) != cache_gen)
-		need_clear = true;
-	if (btrfs_test_opt(info, CLEAR_CACHE))
-		need_clear = true;
-
 	while (1) {
 		struct btrfs_block_group_item_v2 bgi;
 		struct extent_buffer *leaf;

@@ -2686,7 +2662,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
 
 		btrfs_item_key_to_cpu(leaf, &key, slot);
 		btrfs_release_path(path);
-		ret = read_one_block_group(info, &bgi, &key, need_clear);
+		ret = read_one_block_group(info, &bgi, &key);
 		if (ret < 0)
 			goto error;
 		key.objectid += key.offset;

@@ -3539,10 +3515,6 @@ int btrfs_update_block_group(struct btrfs_trans_handle *trans,
 	spin_lock(&space_info->lock);
 	spin_lock(&cache->lock);
 
-	if (btrfs_test_opt(info, SPACE_CACHE) &&
-	    cache->disk_cache_state < BTRFS_DC_CLEAR)
-		cache->disk_cache_state = BTRFS_DC_CLEAR;
-
 	old_val = cache->used;
 	if (alloc) {
 		old_val += num_bytes;

@@ -20,13 +20,6 @@ struct btrfs_fs_info;
 struct btrfs_inode;
 struct btrfs_trans_handle;
 
-enum btrfs_disk_cache_state {
-	BTRFS_DC_WRITTEN,
-	BTRFS_DC_ERROR,
-	BTRFS_DC_CLEAR,
-	BTRFS_DC_SETUP,
-};
-
 enum btrfs_block_group_size_class {
 	/* Unset */
 	BTRFS_BG_SZ_NONE,

@@ -131,7 +124,6 @@ struct btrfs_block_group {
 	u64 delalloc_bytes;
 	u64 bytes_super;
 	u64 flags;
-	u64 cache_generation;
 	u64 global_root_id;
 	u64 remap_bytes;
 	u32 identity_remap_count;

@@ -171,8 +163,6 @@ struct btrfs_block_group {
 	unsigned long full_stripe_len;
 	unsigned long runtime_flags;
 
-	enum btrfs_disk_cache_state disk_cache_state;
-
 	/* Cache tracking stuff */
 	enum btrfs_caching_type cached;
 	struct btrfs_caching_control *caching_ctl;

@@ -4864,10 +4864,6 @@ void btrfs_cleanup_dirty_bgs(struct btrfs_transaction *cur_trans,
 					 dirty_list);
 
 		list_del_init(&cache->dirty_list);
-		spin_lock(&cache->lock);
-		cache->disk_cache_state = BTRFS_DC_ERROR;
-		spin_unlock(&cache->lock);
-
 		spin_unlock(&cur_trans->dirty_bgs_lock);
 		btrfs_put_block_group(cache);
 		btrfs_dec_delayed_refs_rsv_bg_updates(fs_info);

@@ -143,7 +143,6 @@ struct inode *lookup_free_space_inode(struct btrfs_block_group *block_group,
 		btrfs_info(fs_info, "Old style space inode found, converting.");
 		BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 			BTRFS_INODE_NODATACOW;
-		block_group->disk_cache_state = BTRFS_DC_CLEAR;
 	}
 
 	if (!test_and_set_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags))