zstd_alloc_workspace
case BTRFS_COMPRESS_ZSTD: return zstd_alloc_workspace(fs_info, level);
struct list_head *zstd_alloc_workspace(struct btrfs_fs_info *fs_info, int level);
ws = zstd_alloc_workspace(fs_info, ZSTD_BTRFS_MAX_LEVEL);
ws = zstd_alloc_workspace(fs_info, level);