mapping_set_error(9)

okay bestie, welcome to mapping_set_error(9) from the Kernel API Manual — it's literally about recording a writeback error in the address_space, no cap. 💅

💖 NAME 💖

• mapping_set_error — record a writeback error in the address_space.

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✨ SYNOPSIS ✨

void mapping_set_error (struct address_space *mapping , int error );

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🎀 ARGUMENTS 🎀

• mapping — the mapping where an error should be set. that's the spot, bestie.
• error — the error to set in the mapping. yes, that exact one.

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🦋 DESCRIPTION 🦋

okay so picture this: when writeback fails in some way, we must record that error so userspace can be informed when fsync and the like are called. We endeavor to report errors on any file that was open at the time of the error. Some internal callers also need to know when writeback errors have occurred. iykyk.

When a writeback error occurs, most filesystems will want to call mapping_set_error to record the error in the mapping so that it can be reported when the application calls fsync(2). that's the whole vibe: record it in the mapping, let fsync(2) spill the tea later. 🫖✨

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🌈 SEE ALSO 🌈

bestie, the Kernel file ./include/linux/pagemap.h has a whole entourage. here's the full squad, exactly as listed:

• filemap_set_wb_err(9)
• filemap_check_wb_err(9)
• filemap_sample_wb_err(9)
• file_sample_sb_err(9)
• mapping_set_large_folios(9)
• mapping_align_index(9)
• mapping_pmd_folio_support(9)
• folio_flush_mapping(9)
• folio_inode(9)
• folio_attach_private(9)
• folio_change_private(9)
• folio_detach_private(9)
• fgf_t(9)
• fgf_set_order(9)
• write_begin_get_folio(9)
• filemap_get_folio(9)
• filemap_lock_folio(9)
• filemap_grab_folio(9)
• find_get_page(9)
• find_lock_page(9)
• find_or_create_page(9)
• grab_cache_page_nowait(9)
• folio_next_index(9)
• folio_next_pos(9)
• folio_file_page(9)
• folio_contains(9)
• page_pgoff(9)
• folio_pos(9)
• linear_page_delta(9)
• linear_page_index(9)
• linear_anon_page_index(9)
• folio_trylock(9)
• folio_lock(9)
• lock_page(9)
• folio_lock_killable(9)
• filemap_range_needs_writeback(9)
• struct readahead_control(9)
• page_cache_sync_readahead(9)
• page_cache_async_readahead(9)
• readahead_folio(9)
• readahead_pos(9)
• readahead_length(9)
• readahead_index(9)
• readahead_count(9)
• readahead_batch_length(9)
• folio_mkwrite_check_truncate(9)
• i_blocks_per_folio(9)

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mwah 💋 this lil page lives at source/version ./include/linux, dated October 2026, and it's the mapping_set_error(9) glow-up. byeee 🫶🌸