generic_file_write_iter(9)

✨ generic_file_write_iter(9) ✨

okay bestie, welcome to the Kernel API Manual — this one's all about generic_file_write_iter, and it is literally the moment. 💅

---

🌸 NAME 🌸

generic_file_write_iter — write data to a file, no cap

---

🎀 SYNOPSIS 🎀

ssize_t generic_file_write_iter (struct kiocb *iocb , struct iov_iter
*from );

---

🦋 ARGUMENTS 🦋

• iocb — the IO state structure, aka the vibe check for your IO 🫶
• from — the iov_iter holding the data you wanna write ✨

---

💖 DESCRIPTION 💖

so basically this is a wrapper around __generic_file_write_iter, and it's the one most filesystems use. it's giving main character energy for sure. 🔥

it handles syncing the file when you're doing an O_SYNC file, and it acquires i_rwsem as needed. iconic behavior, honestly. 👑

---

⭐ RETURN ⭐

• negative error code if no data has been written at all, or if vfs_fsync_range failed for a synchronous write 😭
• number of bytes written — even for truncated writes, periodt 💀

---

🌈 SEE ALSO 🌈

the Kernel file ./mm/filemap.c is the source, and honestly the whole friend group is here. say hi to: filemap_remove_folio(9), filemap_fdatawrite_range(9), filemap_flush_range(9), filemap_flush(9), filemap_range_has_page(9), filemap_fdatawait_range(9), filemap_fdatawait_range_keep_errors(9), file_fdatawait_range(9), filemap_fdatawait_keep_errors(9), filemap_write_and_wait_range(9), file_check_and_advance_wb_err(9), file_write_and_wait_range(9), replace_page_cache_folio(9), softleaf_entry_wait_on_locked(9), folio_put_wait_locked(9), folio_unlock(9), folio_end_read(9), folio_end_private_2(9), folio_wait_private_2(9), folio_wait_private_2_killable(9), folio_end_writeback_no_dropbehind(9), folio_end_writeback(9), __folio_lock(9), page_cache_next_miss(9), page_cache_prev_miss(9), __filemap_get_folio_mpol(9), find_get_entries(9), find_lock_entries(9), filemap_get_folios(9), filemap_get_folios_contig(9), filemap_get_folios_tag(9), filemap_get_folios_dirty(9), filemap_read(9), generic_file_read_iter(9), filemap_splice_read(9), mapping_seek_hole_data(9), filemap_fault(9), read_cache_folio(9), mapping_read_folio_gfp(9), read_cache_page_gfp(9), __generic_file_write_iter(9), filemap_release_folio(9), filemap_invalidate_inode(9), and filemap_cachestat(9). the whole squad, fr fr 🧚‍♀️💜

---

and that's the page, bestie! this one's from ./mm, dated October 2026 — so yeah, it's fresh, it's relevant, and it ate. 🍓👑💫