is_slab_journal_blank(9)

🌸 is_slab_journal_blank(9) 🌸

okay so bestie, welcome to the Kernel API Manual, section 9 — yes we're in the big-kid kernel docs now, and honestly? it's giving main character energy. this one's a lil function, but she's important, so let's get into it 💅

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✨ NAME ✨

is_slab_journal_blank — check whether a slab's journal is blank. that's it, that's the whole vibe check 🎀

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🦋 SYNOPSIS 🦋

bool is_slab_journal_blank (const struct vdo_slab *slab );

like, she takes one thing and she hands you back a bool. no cap, that's the whole signature 🫶

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💖 ARGUMENTS 💖

• slab — the slab you wanna check. that's the one. the only one. give her the slab and she'll tell you what's up ✨

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🌸 DESCRIPTION 🌸

so a slab journal is considered blank if it has never had any entries recorded in it. like, never ever. not a single one. pristine. untouched. brand new journal energy 💀

that's literally the whole definition — nothing mysterious going on here, she's just asking "has this thing ever been written to?" 🙈

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⭐ RETURN ⭐

returns True if the slab's journal has never been modified. lowkey the simplest return value ever and we love that for us 👑

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🔥 SEE ALSO 🔥

okay so this is the part where the manpage goes absolutely feral — we're talking the whole friend group. all of these live in the kernel file ./drivers/md/dm-vdo/slab-depot.c, and they're all section 9:

get_lock(9), must_make_entries_to_flush(9), is_reaping(9), initialize_tail_block(9), initialize_journal_state(9), block_is_full(9), mark_slab_journal_dirty(9), compute_fullness_hint(9), check_summary_drain_complete(9), notify_summary_waiters(9), finish_updating_slab_summary_block(9), finish_update(9), handle_write_error(9), launch_write(9), update_slab_summary_entry(9), finish_reaping(9), complete_reaping(9), handle_flush_error(9), flush_for_reaping(9), reap_slab_journal(9), adjust_slab_journal_block_reference(9), release_journal_locks(9), update_tail_block_location(9), reopen_slab_journal(9), complete_write(9), write_slab_journal_block(9), commit_tail(9), encode_slab_journal_entry(9), expand_journal_point(9), add_entry(9), vdo_attempt_replay_into_slab(9), requires_reaping(9), launch_reference_block_write(9), finish_reference_block_write(9), get_reference_counters_for_block(9), pack_reference_block(9), handle_io_error(9), write_reference_block(9), reference_count_to_status(9), dirty_block(9), get_reference_block(9), slab_block_number_from_pbn(9), get_reference_counter(9), adjust_free_block_count(9), increment_for_data(9), decrement_for_data(9), increment_for_block_map(9), update_reference_count(9), add_entry_from_waiter(9), is_next_entry_a_block_map_increment(9), add_entries(9), reset_search_cursor(9), advance_search_cursor(9), vdo_adjust_reference_count_for_rebuild(9), replay_reference_count_change(9), find_zero_byte_in_word(9), find_free_block(9), search_current_reference_block(9), search_reference_blocks(9), make_provisional_reference(9), dirty_all_reference_blocks(9), match_bytes(9), count_valid_references(9), unpack_reference_block(9), finish_reference_block_load(9), load_reference_block_group(9), load_reference_blocks(9), drain_slab(9), read_slab_journal_tail(9), load_slab_journal(9), get_next_slab(9), has_slabs_to_scrub(9), uninitialize_scrubber_vio(9), finish_scrubbing(9), slab_scrubbed(9), abort_scrubbing(9), handle_scrubber_error(9), apply_block_entries(9), apply_journal_entries(9), start_scrubbing(9), scrub_next_slab(9), scrub_slabs(9), get_depot_slab_iterator(9), next_slab(9), abort_waiter(9), vdo_acquire_provisional_reference(9), open_slab(9), vdo_enqueue_clean_slab_waiter(9), vdo_modify_reference_count(9), vdo_notify_slab_journals_are_recovered(9), make_slab(9), allocate_slabs(9), vdo_abandon_new_slabs(9), release_recovery_journal_lock(9), prepare_for_tail_block_commit(9), schedule_tail_block_commit(9), initialize_slab_scrubber(9), initialize_slab_summary_block(9), vdo_decode_slab_depot(9), vdo_free_slab_depot(9), vdo_record_slab_depot(9), vdo_allocate_reference_counters(9), get_slab_number(9), vdo_get_slab(9), vdo_get_increment_limit(9), vdo_is_physical_data_block(9), vdo_get_slab_depot_allocated_blocks(9), vdo_get_slab_depot_data_blocks(9), finish_combining_zones(9), combine_summaries(9), finish_loading_summary(9), load_slab_summary(9), vdo_load_slab_depot(9), vdo_prepare_slab_depot_to_allocate(9), vdo_update_slab_depot_size(9), vdo_prepare_to_grow_slab_depot(9), finish_registration(9), vdo_use_new_slabs(9), stop_scrubbing(9), vdo_drain_slab_depot(9), resume_scrubbing(9), vdo_resume_slab_depot(9), vdo_commit_oldest_slab_journal_tail_blocks(9), vdo_scrub_all_unrecovered_slabs(9), get_block_allocator_statistics(9), get_ref_counts_statistics(9), get_slab_journal_statistics(9), vdo_get_slab_depot_statistics(9), vdo_dump_slab_depot(9)

fr fr that's the entire squad — 100+ functions and not one of them skipped, because we don't do half-finished SEE ALSO lists around here 💜

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anyway bestie, that's the page!! source is ./drivers/md/dm-vdo, dated October 2026 — go forth and check those slab journals, you absolute icon 🌈👑💅