writeback_inodes_sb(9)

💖 writeback_inodes_sb(9) 💖

okay so real talk bestie, welcome to the writeback_inodes_sb(9) page — it lives in the Kernel API Manual and it's like, short but important, yk? grab a lil snack and let's get into it 🍓

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✨ NAME ✨

writeback_inodes_sb — writeback dirty inodes from given super_block 💅

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✨ SYNOPSIS ✨

void writeback_inodes_sb (struct super_block *sb , enum wb_reason reason
);

literally that's the whole signature. no cap, it's a void function so it doesn't hand anything back to you 🫶

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✨ ARGUMENTS ✨

• sb — the superblock. that's the one. the main character. 👑
• reason — the reason why some writeback work was initiated. like, why are we doing this, bestie? now it's on the record ✨

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✨ DESCRIPTION ✨

So what it does: it starts writeback on some inodes on this super_block. that's the vibe. 🌈

And here's the part you gotta internalize, fr fr — no guarantees are made on how many (if any) will be written. could be a bunch, could be zero, could be one sad little inode. the universe decides. 💀

Also, and this is the big one: this function does not wait for IO completion of submitted IO. so like, it kicks things off and then dips. it's giving "seen at 2:47 AM" energy. if you were expecting it to hang around until the IO is done, sorry bestie, that's not this function 😭

lowkey important: non-waiting = you can't assume anything is flushed to disk when it returns. that's the whole caveat, don't sleep on it 🙈

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✨ SEE ALSO ✨

Kernel file ./fs/fs-writeback.c — and honestly the whole squad shows up here, go say hi to all of them:

• inode_io_list_move_locked(9)
• wb_wait_for_completion(9)
• inode_cgwb_move_to_attached(9)
• locked_inode_to_wb_and_lock_list(9)
• inode_to_wb_and_lock_list(9)
• inode_switch_wbs(9)
• cleanup_offline_cgwb(9)
• wbc_attach_and_unlock_inode(9)
• wbc_attach_fdatawrite_inode(9)
• wbc_detach_inode(9)
• wbc_account_cgroup_owner(9)
• wb_split_bdi_pages(9)
• bdi_split_work_to_wbs(9)
• cgroup_writeback_by_id(9)
• cgroup_writeback_umount(9)
• wb_start_background_writeback(9)
• filemap_dontcache_kick_writeback(9)
• __mark_inode_dirty(9)
• writeback_inodes_sb_nr(9)
• try_to_writeback_inodes_sb(9)
• sync_inodes_sb(9)
• write_inode_now(9)
• sync_inode_metadata(9)

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and that's the page!! 🦋 lil sign-off for you: this one came out of ./fs, dated October 2026, and it's filed under writeback_inodes_sb(9) — so if you ever forget where you read it, now you know 💜✨ periodt.