bh_submit(9)

💅 bh_submit(9) — like, the buffer head I/O starter pack

okay bestie, so this is a kernel API manual page, section 9 (that's the kernel API section, iykyk), and the star of the show is bh_submit. grab a snack, we're doing I/O 💖

---

✨ NAME ✨

bh_submit — start I/O against a buffer head. that's it, that's the vibe 🦋

---

✨ SYNOPSIS ✨

void bh_submit (struct buffer_head *bh , blk_opf_t opf , bio_end_io_t
end_io );

like, it returns void, so don't go looking for a return value, there isn't one, periodt 💅

---

✨ ARGUMENTS ✨

• bh — the buffer head you're doing the I/O on. this is literally the main character of the whole function 👑
• opf — the operation and flags for the bio. all the "what are we even doing here" energy lives in this one 🎀
• end_io — the routine that gets called when the I/O has completed. your little callback bestie that shows up once the work is done 🫶

---

✨ DESCRIPTION ✨

so here's the tea 🍓 — if you need to do I/O on an individual bh, instead of letting the page cache do the I/O on the folio that it's in, then you call this function. that's the whole thing. no cap, that's the entire description, and honestly? iconic. short, sweet, slays 💖

lowkey important: it's bh on its own, not the folio it lives inside. keep that distinction in your head, bestie, it's giving main character energy 🌸

---

✨ SEE ALSO ✨

all the related lore, straight from the kernel files under ./fs/buffer.c — go read these next, they're the friend group 🧚

• bio_endio_bh(9)
• end_buffer_read_sync(9)
• bh_end_read(9)
• bh_end_write(9)
• bh_end_async_write(9)
• mmb_sync(9)
• block_dirty_folio(9)
• mark_buffer_dirty(9)
• __brelse(9)
• __bforget(9)
• bdev_getblk(9)
• __bread_gfp(9)
• block_invalidate_folio(9)
• clean_bdev_aliases(9)
• try_to_free_buffers(9)
• bh_uptodate_or_lock(9)
• __bh_read(9)
• __bh_read_batch(9)

---

and that's the page, bestie!! 🎀 this one's from the ./fs corner of the kernel, dated October 2026 — so go forth, submit that buffer head I/O, and slay ✨💜🔥