is_hash_collision(9)

💖 is_hash_collision 💖

okay bestie, welcome to the Kernel API Manual page for is_hash_collision(9) — yes, we're doing kernel hash-lock lore today and it's lowkey iconic ✨

🌸 NAME 🌸

is_hash_collision — check to see if a hash collision has occurred. That's the whole vibe check, no cap 💅

✨ SYNOPSIS ✨

bool is_hash_collision (struct hash_lock *lock , struct data_vio
       *candidate );

💅 ARGUMENTS 💅

• lock — the lock to check, bestie.
• candidate — the data_vio seeking to share the lock; main character energy, but for lock-sharing 🫶

🦋 DESCRIPTION 🦋

Check whether the data in data_vios sharing a lock is different than in a data_vio seeking to share the lock. This should only be possible in the extremely unlikely case of a hash collision. It's giving rare edge case, highkey why we check 💀✨

🎀 RETURN 🎀

The return is true if the given data_vio must not share the lock because it doesn't have the same data as the lock holders. Periodt — that's the return value 🎀

🌈 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)
• lock_duplicate_pbn(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)
• 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)

xoxo, your kernel manual bestie 💖 — source/version: ./drivers/md/dm-vdo; date: October 2026; page: is_hash_collision(9) 🎀