filemap_fdatawrite_range(9)

💖 filemap_fdatawrite_range — Kernel API Manual ✨

okay so bestie, welcome to the Kernel API Manual entry for filemap_fdatawrite_range(9) — the function that literally tells your dirty pages to go get written out, but only the ones chilling in a specific byte range. no cap, it's a whole thing. 🎀

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✨ NAME ✨

filemap_fdatawrite_range — start writeback on mapping dirty pages in range 🦋

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🌸 SYNOPSIS 🌸

int filemap_fdatawrite_range (struct address_space *mapping , loff_t start , loff_t end );

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💜 ARGUMENTS 💜

• mapping — the address space structure to write, bestie. this is the thing that owns all the pages we're about to poke. 👑
• start — offset in bytes where the range starts 📍
• end — offset in bytes where the range ends (inclusive!) — yes, inclusive, don't forget that part 🙈

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🔥 DESCRIPTION 🔥

Start writeback against all of a mapping's dirty pages that lie within the byte offsets <start, end> inclusive. so like, the boundaries are in the club too. 💅

This is a data integrity operation that waits upon dirty or in writeback pages. it's giving "i'm not leaving until everybody's sorted" energy, fr fr. 😭✨

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⭐ RETURN ⭐

0 on success, negative error code otherwise. slay when it's zero, sad when it's negative. 🫶

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🌈 SEE ALSO 🌈

Kernel file ./mm/filemap.c, plus literally this whole friend group:

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

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bestie this list is LONG but every single one of them is iconic in their own way 💀 don't skip a single name, they all matter.

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and that's the whole page!! sign-off time: this one lives under ./mm, dated October 2026, and it's filemap_fdatawrite_range(9) — go forth and write back those pages, queen 👑💖✨