make_forest(9)

🌲 make_forest(9) — the kernel API manual, bestie edition 🫶

Okay so this is make_forest(9) from the Kernel API Manual — yes, that's the whole vibe, kernel-API-manual-core 💅 — and today we're learning how to grow a whole lil forest of trees for a block map. Sit down, hydrate, let's go ✨

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🌸 NAME 🌸

make_forest — Make a collection of trees for a block_map, expanding the existing forest if there is one.

Like. It literally plants trees. For a block map. And if a forest is already chilling there, it just makes it bigger instead of starting over — respectful, efficient, main character energy honestly 👑

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✨ SYNOPSIS ✨

int make_forest (struct block_map *map , block_count_t entries );

That's the whole thing. Two args, one int back. Iconic. Short. Ate. 🎀

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🦋 ARGUMENTS 🦋

• map — The block map. That's it, that's the whole description. She's the block map, she's the moment, the forest gets planted inside her 🌈
• entries — The number of entries the block map will hold. So like, how much room bestie needs. This number decides how big the forest situation gets 🌸

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💜 RETURN 💜

VDO_SUCCESS — or an error 😭

That's the deal. You either slay or you don't, there's genuinely no in-between, no cap 🔥

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🧚 SEE ALSO 🧚

Kernel file ./drivers/md/dm-vdo/block-map.c

Block map — the extended universe, and listen, it's a whole friend group, we're listing every single one of them because none of them are getting left out 🫶:

• eras(9)
• initialize_info(9)
• allocate_cache_components(9)
• assert_on_cache_thread(9)
• get_page_state_name(9)
• update_counter(9)
• set_info_state(9)
• find_free_page(9)
• find_page(9)
• select_lru_page(9)
• complete_with_page(9)
• complete_waiter_with_error(9)
• complete_waiter_with_page(9)
• distribute_page_over_waitq(9)
• set_persistent_error(9)
• validate_completed_page(9)
• handle_load_error(9)
• page_is_loaded(9)
• handle_rebuild_read_error(9)
• launch_page_load(9)
• schedule_page_save(9)
• launch_page_save(9)
• completion_needs_page(9)
• allocate_free_page(9)
• discard_a_page(9)
• discard_page_if_needed(9)
• write_has_finished(9)
• handle_page_write_error(9)
• page_is_written_out(9)
• write_pages(9)
• vdo_release_page_completion(9)
• vdo_get_page(9)
• vdo_request_page_write(9)
• vdo_get_cached_page(9)
• vdo_invalidate_page_cache(9)
• get_tree_page_by_index(9)
• in_cyclic_range(9)
• is_not_older(9)
• add_to_dirty_lists(9)
• vdo_find_block_map_slot(9)
• replace_forest(9)
• finish_cursor(9)
• continue_traversal(9)
• finish_traversal_load(9)
• traverse(9)
• launch_cursor(9)
• compute_boundary(9)
• vdo_traverse_forest(9)
• initialize_block_map_zone(9)
• clear_mapped_location(9)
• set_mapped_location(9)

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Fr fr, read the neighbors too — replace_forest(9) and vdo_traverse_forest(9) are literally right there and they're obsessed with you 💖

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Okay that's the page!! Sourced from ./drivers/md/dm-vdo, dated October 2026 — and hey, don't forget to check in on make_forest(9) again next time, she's got trees to grow 🌳✨💅