folio_end_writeback(9)

💅 folio_end_writeback — from the Kernel API Manual, bestie ✨

okay so real talk, this one is a tiny little function with a big responsibility, and the manpage is short enough that we can absolutely devour it in one sitting 🫶

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✨ NAME ✨

folio_end_writeback — literally just: end writeback against a folio. that's the whole vibe. 💫

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🎀 SYNOPSIS 🎀

void folio_end_writeback (struct folio *folio );

one function, one arg, returns nothing. no notes. 👑

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🌸 ARGUMENTS 🌸

• folio — the folio. yes that's the entire description. she's mysterious, she's iconic, she contains multitudes 💅

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🦋 DESCRIPTION 🦋

k so here's the one thing you cannot fumble: the folio must actually be under writeback. like, for real. it's not a "close enough" situation, it's not a "we'll figure it out" situation. it has to genuinely be in writeback rn or this is not it, bestie 😭

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🧚 CONTEXT 🧚

the good news?? you can call this from process context or interrupt context. flexible queen. no cap. ✨

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🔥 SEE ALSO 🔥

this list is long and honestly kinda giving "she knows everybody at the party" energy, so buckle up, we're going through the whole guest list 💖

all of these live in the kernel file ./mm/filemap.c:

• 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_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)
• generic_file_write_iter(9)
• filemap_release_folio(9)
• filemap_invalidate_inode(9)
• filemap_cachestat(9)

like… 45 entries. she said "I have a support system" and she meant it 💀💖

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⭐ friendly reminder from your girl: that "the folio must actually be under writeback" line is the whole personality of this function. don't skip it, don't soften it, don't pretend you didn't read it 🙈

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and that's the page, bestie!! this one came from ./mm and it's dated October 2026 🗓️✨ mwah, go forth and end that writeback correctly 🎀💜🦋