drbd_queue_bitmap_io(9)

📦 version 7.3.1, in nixpkgs unstable

💫 drbd_queue_bitmap_io(9) 💫

okay so bestie, welcome to the drbd_queue_bitmap_io(9) page from the Kernel API Manual — this is the one that queues up an IO operation across the whole bitmap, and honestly? kind of iconic of it. 🎀

✨ NAME ✨

drbd_queue_bitmap_io — the function that queues an IO operation on the entire bitmap, no cap. 🌈

🦋 SYNOPSIS 🦋

void drbd_queue_bitmap_io (struct drbd_device *device , int
(*io_fn)(struct drbd_device *, struct drbd_peer_device *) , void
(*done)(struct drbd_device *, int) , char *why , enum bm_flag flags ,
struct drbd_peer_device *peer_device );

like, that's the whole signature, copy it exactly bestie, do not come for me about the line breaks 😭

🌸 ARGUMENTS 🌸

  • device — the DRBD device. the main character of this whole situation tbh 👑
  • io_fn — the IO callback. this is the one that gets called when bitmap IO is actually possible, so it's lowkey the star of the show ⭐
  • done — the callback that's called after the bitmap IO was performed. the afterparty, if you will 🎉
  • why — descriptive text explaining the reason for doing the IO. literally just your receipts, keep them 💅
  • flags — bitmap flags. enum bm_flag energy 🧚
  • peer_device — the peer DRBD device. every main character needs their bestie 🫶

💜 DESCRIPTION 💜

so here's the vibe: while IO on the bitmap is happening, we freeze application IO, which means we make sure drbd_set_out_of_sync can not be called. yeah. that's the whole point. 🔥

⚠️ okay this part matters, bestie, listen up: this function MAY ONLY be called from worker context. like, that's not a suggestion, that's the rule. and it MUST NOT be used while a previous such work is still pending! no stacking, no overlapping, none of that 🙈

and for the nerdy details: its worker function encloses the call of io_fn by get_ldev and put_ldev. so io_fn is literally wrapped up all cozy in there 🎀✨

💀 SEE ALSO 💀

all the related lore, in the kernel file ./drivers/block/drbd/drbd_main.c:

and that's the whole page, bestie!! it lives in ./drivers/block/drbd, dated October 2026 — so yeah, mark your calendar, screenshot it, send it to the group chat, this one's a keeper 💖✨🦋💅

mwah, go freeze some application IO responsibly 🍓

📦 where this page comes from