notify_vdo_o...ad_only_mode(9)

💅 notify_vdo_of_read_only_mode — like, the dm-vdo kernel API manual, bestie

Okay so we are diving into notify_vdo_of_read_only_mode(9) from the Kernel API Manual (it's a whole (9) situation, very section-9 of it) — and honestly? It's giving "tiny function, big reputation." Let's get into it 🫶

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✨ NAME ✨

notify_vdo_of_read_only_mode — the moment where you gently tell a vdo that it's going read-only. Like a soft launch, but for write protection 💀

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🌸 SYNOPSIS 🌸

void notify_vdo_of_read_only_mode (void *listener , struct
     vdo_completion *parent );

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🎀 ARGUMENTS 🎀

• listener — the vdo itself. Yes bestie, it's typed as a void *, we don't ask questions, we just vibe 💜
• parent — the completion you notify so it can, y'know, acknowledge that the notification happened. It's the "seen ✅" of the kernel world, no cap.

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🦋 DESCRIPTION 🦋

So what does this actually do? It saves the read-only state to the super block. That's it, that's the whole main character moment ✨

It also implements vdo_read_only_notification_fn. Periodt. 🔥

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👑 SEE ALSO 👑

Kernel file ./drivers/md/dm-vdo/vdo.c — plus, like, the entire extended friend group:

Introduction(9), vdo_initialize_device_registry_once(9), filter_vdos_locked(9), vdo_find_matching(9), initialize_thread_config(9), get_thread_name(9), vdo_make_thread(9), register_vdo(9), vdo_format(9), initialize_vdo(9), vdo_make(9), free_listeners(9), unregister_vdo(9), vdo_destroy(9), finish_reading_super_block(9), handle_super_block_read_error(9), vdo_load_super_block(9), vdo_get_backing_device(9), vdo_get_device_name(9), vdo_synchronous_flush(9), vdo_get_state(9), vdo_set_state(9), vdo_get_admin_state(9), record_vdo(9), continue_parent(9), handle_geometry_block_save_error(9), vdo_save_geometry_block(9), handle_super_block_save_error(9), vdo_save_super_block(9), vdo_save_components(9), vdo_register_read_only_listener(9), vdo_enable_read_only_entry(9), vdo_wait_until_not_entering_read_only_mode(9), as_notifier(9), finish_entering_read_only_mode(9), make_thread_read_only(9), vdo_allow_read_only_mode_entry(9), vdo_enter_read_only_mode(9), vdo_is_read_only(9), vdo_in_read_only_mode(9), vdo_in_recovery_mode(9), vdo_enter_recovery_mode(9), complete_synchronous_action(9), perform_synchronous_action(9), set_compression_callback(9), vdo_set_compressing(9), vdo_get_compressing(9), vdo_get_physical_blocks_allocated(9), vdo_get_physical_blocks_overhead(9), get_vdo_statistics(9), vdo_fetch_statistics_callback(9), vdo_fetch_statistics(9), vdo_get_callback_thread_id(9), vdo_dump_status(9), vdo_assert_on_admin_thread(9), vdo_assert_on_logical_zone_thread(9), vdo_assert_on_physical_zone_thread(9), vdo_get_physical_zone(9) 🧚

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That's the whole page, bestie — short, sweet, and lowkey iconic 🌈

Sourced from ./drivers/md/dm-vdo, dated October 2026, and yeah the title up top is still notify_vdo_o...ad_only_mode(9) because the header truncation said "we're not fixing it, we're slaying it" 💅✨