filemap_fda..._keep_errors(9)

💖 filemap_fdatawait_keep_errors 💖

okay so this is a page straight out of the Kernel API Manual (yes, section 9, the big-leagues one) and honestly? it's a little baddie with a very specific job. let's get into it 🫶

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✨ NAME ✨

filemap_fdatawait_keep_errors — bestie, this one waits for writeback and does not clear your errors. that's the whole personality. 💅

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🌸 SYNOPSIS 🌸

int filemap_fdatawait_keep_errors (struct address_space *mapping );

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🎀 ARGUMENTS 🎀

• mapping — the address space structure you're waiting on. that's your girl right there, she's the one you're stalking (affectionately) until she's done. ✨

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🦋 DESCRIPTION 🦋

so what it actually does: it walks the list of under-writeback pages in the given address space and waits for all of them. all of them. every last one. no skipping, no shortcuts. 😭

but here's the plot twist, and it's giving main character energy: unlike filemap_fdatawait, this function does not clear the error status of the address space. it keeps those errors. it's literally in the name, iykyk. 💀

use this one if your callers don't handle errors themselves. like, they're not gonna deal with it, so you shouldn't be wiping the evidence. 🙈

expected call sites are the system-wide / filesystem-wide data flushers, for example sync(2) and fsfreeze(8). yes, those ones. the big flushy ones. 🔥

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💜 RETURN 💜

it returns the error status of the address space. that's it, that's the tea. ⭐

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👑 SEE ALSO 👑

first up, the kernel file itself: ./mm/filemap.c — that's where the magic lives. 🧚

and now the full friend group, everybody say hi:

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

like, that's the whole gc right there. go read them too. 🌈

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and that's the page!! brought to you by the ./mm crew, dated October 2026, and yeah the title's a little truncated in the header because apparently we ran out of room 😭 — filemap_fda..._keep_errors(9) forever, an icon, a legend, a shortened queen. 💖✨🎀