lock_duplicate_pbn(9)

💅 lock_duplicate_pbn(9) — the lock_duplicate_pbn(9) kernel API manual, but make it make sense

okay so bestie, welcome to the lock_duplicate_pbn(9) glow-up ✨ this is the section 9 kernel API page, and we're gonna get you comfy with it, no cap.

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🌸 NAME 🌸

lock_duplicate_pbn — grab a read lock on the PBN of the block that's holding your candidate duplicate data (could be compressed, could be not, either way we're locking it 💖).

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🎀 SYNOPSIS 🎀

void lock_duplicate_pbn (struct vdo_completion *completion );

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🦋 ARGUMENTS 🦋

• completion — the completion of the data_vio that's out here trying to acquire the physical block lock on behalf of its hash lock. like, it's doing the lock-acquiring errand for the hash lock, that's the whole vibe 🫶

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✨ DESCRIPTION ✨

so here's the tea ☕ — if the PBN is already locked for writing, the lock attempt gets abandoned, and is_duplicate is cleared before calling back. periodt, that's just how it goes.

also important: this continuation is launched from start_locking, and it calls back to finish_locking on the hash zone thread 🧚

ngl this is one of those tiny functions that's lowkey load-bearing — remember the abandon path, bestie, or the callback's gonna catch you off guard 😭

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🔥 SEE ALSO 🔥

• Kernel file ./drivers/md/dm-vdo/dedupe.c
• Introduction(9)
• return_hash_lock_to_pool(9)
• vdo_get_duplicate_lock(9)
• hash_lock_key(9)
• get_hash_lock_state_name(9)
• assert_hash_lock_agent(9)
• set_duplicate_lock(9)
• dequeue_lock_waiter(9)
• set_hash_lock(9)
• exit_hash_lock(9)
• set_duplicate_location(9)
• retire_lock_agent(9)
• wait_on_hash_lock(9)
• abort_waiter(9)
• start_bypassing(9)
• finish_unlocking(9)
• unlock_duplicate_pbn(9)
• start_unlocking(9)
• finish_updating(9)
• start_updating(9)
• finish_deduping(9)
• acquire_lock(9)
• enter_forked_lock(9)
• fork_hash_lock(9)
• launch_dedupe(9)
• start_deduping(9)
• increment_stat(9)
• finish_verifying(9)
• start_verifying(9)
• finish_locking(9)
• start_locking(9)
• finish_writing(9)
• select_writing_agent(9)
• start_writing(9)
• finish_querying(9)
• start_querying(9)
• report_bogus_lock_state(9)
• vdo_continue_hash_lock(9)
• is_hash_collision(9)
• vdo_acquire_hash_lock(9)
• vdo_release_hash_lock(9)
• transfer_allocation_lock(9)
• vdo_share_compressed_write_lock(9)
• report_dedupe_timeouts(9)
• finish_index_operation(9)
• check_for_drain_complete(9)
• vdo_make_hash_zones(9)
• vdo_free_hash_zones(9)
• suspend_index(9)
• resume_index(9)
• vdo_resume_hash_zones(9)
• get_hash_zone_statistics(9)
• vdo_get_dedupe_statistics(9)
• vdo_select_hash_zone(9)
• dump_hash_lock(9)
• dump_hash_zone(9)
• vdo_dump_hash_zones(9)
• acquire_context(9)

that's a lot of links and honestly? iconic. go read them, iykyk 👑

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🎀 ok that's the whole page, bestie! this lil gem lives in ./drivers/md/dm-vdo and it's dated October 2026 — so mark your calendar, screenshot it, whatever you gotta do 💜 slay, and happy locking!! 🦋💖