btrfs: convert btrfs_block_group::needs_free_space to runtime flag

[ Upstream commit 0d7764f ]

We already have flags in block group to track various status bits,
convert needs_free_space as well and reduce size of btrfs_block_group.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 0657b20 ("btrfs: fix use-after-free of new block group that became unused")
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/btrfs/block-group.c

@@ -2543,7 +2543,7 @@ struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *tran
 	cache->global_root_id = calculate_global_root_id(fs_info, cache->start);
 
 	if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
-		cache->needs_free_space = 1;
+		set_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &cache->runtime_flags);
 
 	ret = btrfs_load_block_group_zone_info(cache, true);
 	if (ret) {

fs/btrfs/block-group.h

@@ -55,6 +55,8 @@ enum btrfs_block_group_flags {
 	BLOCK_GROUP_FLAG_CHUNK_ITEM_INSERTED,
 	BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE,
 	BLOCK_GROUP_FLAG_ZONED_DATA_RELOC,
+	/* Does the block group need to be added to the free space tree? */
+	BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE,
 };
 
 enum btrfs_caching_type {
@@ -204,12 +206,6 @@ struct btrfs_block_group {
 	/* Lock for free space tree operations. */
 	struct mutex free_space_lock;
 
-	/*
-	 * Does the block group need to be added to the free space tree?
-	 * Protected by free_space_lock.
-	 */
-	int needs_free_space;
-
 	/* Flag indicating this block group is placed on a sequential zone */
 	bool seq_zone;
 

fs/btrfs/free-space-tree.c

@@ -803,7 +803,7 @@ int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
 	u32 flags;
 	int ret;
 
-	if (block_group->needs_free_space) {
+	if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) {
 		ret = __add_block_group_free_space(trans, block_group, path);
 		if (ret)
 			return ret;
@@ -996,7 +996,7 @@ int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
 	u32 flags;
 	int ret;
 
-	if (block_group->needs_free_space) {
+	if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) {
 		ret = __add_block_group_free_space(trans, block_group, path);
 		if (ret)
 			return ret;
@@ -1350,7 +1350,7 @@ static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
 {
 	int ret;
 
-	block_group->needs_free_space = 0;
+	clear_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags);
 
 	ret = add_new_free_space_info(trans, block_group, path);
 	if (ret)
@@ -1372,7 +1372,7 @@ int add_block_group_free_space(struct btrfs_trans_handle *trans,
 		return 0;
 
 	mutex_lock(&block_group->free_space_lock);
-	if (!block_group->needs_free_space)
+	if (!test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags))
 		goto out;
 
 	path = btrfs_alloc_path();
@@ -1405,7 +1405,7 @@ int remove_block_group_free_space(struct btrfs_trans_handle *trans,
 	if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
 		return 0;
 
-	if (block_group->needs_free_space) {
+	if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) {
 		/* We never added this block group to the free space tree. */
 		return 0;
 	}

fs/btrfs/tests/free-space-tree-tests.c

@@ -470,7 +470,7 @@ static int run_test(test_func_t test_func, int bitmaps, u32 sectorsize,
 	}
 	cache->bitmap_low_thresh = 0;
 	cache->bitmap_high_thresh = (u32)-1;
-	cache->needs_free_space = 1;
+	set_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &cache->runtime_flags);
 	cache->fs_info = root->fs_info;
 
 	btrfs_init_dummy_trans(&trans, root->fs_info);