netfs_writeback_single(9)

✨ netfs_writeback_single — a Kernel API Manual moment ✨

okay so bestie, welcome to netfs_writeback_single(9) 💅 this is a kernel API manual page, section 9, and it's literally about writing back a monolithic payload. yes that's the whole vibe. no cap. 🦋

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🌸 NAME 🌸

netfs_writeback_single — write back a monolithic payload. that's it, that's the function, and honestly? iconic. 🎀

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⭐ SYNOPSIS ⭐

int netfs_writeback_single (struct address_space *mapping , struct
writeback_control *wbc , struct iov_iter *iter );

three arguments, one int coming back at you. main character energy fr fr 🔥

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🫶 ARGUMENTS 🫶

• mapping — the mapping you're writing from, bestie. it's a struct address_space *. that's your source, your origin story, your whole thing 💖
• wbc — hints from the VM, passed in as a struct writeback_control *. the VM is basically sliding into your DMs with advice and you're like "noted 👑"
• iter — the data to write, as a struct iov_iter *. and hear me out: it must be ITER_FOLIOQ. not a suggestion. not a vibe. a requirement. it's giving non-negotiable 💀

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🧚 DESCRIPTION 🧚

so what does it actually do? it writes a monolithic, non-pagecache object back to the server and/or the cache. that's the assignment, and it ate. ✨

like, this thing is not fiddling around with pagecache. it's monolithic. it's one big payload. it goes back to the server, and/or to the cache, and it slays while doing it 🌈

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💜 RETURN 💜

what comes back, you ask? three possibilities, bestie, and you gotta know them all:

• 0 — successful. we love to see it 🎉
• 1 — skipped due to lock conflict, but only when it's WB_SYNC_NONE. like, the lock was busy and you said "not today" 🙈
• a negative error code — something went sideways. 😭 not the vibe, but it's information, and information is power, periodt.

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👑 SEE ALSO 👑

• the Kernel file ./fs/netfs/write_issue.c — go read it, iykyk 📖
• netfs_prepare_write_failed(9) — the other one you'll wanna know about, lowkey important 🍓

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and that's the page, bestie!! 💖 this little gem lives in ./fs/netfs, dated October 2026, from the Kernel API Manual — so go forth, write back your monolithic payloads, and remember: ITER_FOLIOQ or it didn't happen. mwah. 💅🎀🦋🌸🫶