Commit 173a3dc0 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: assert the folio is locked in folio_start_writeback() 

The folio must be locked when we start writeback in order to prevent
writeback from being started twice on the same folio.  I don't expect this
to catch any problems, but it should be good documentation.

Link: https://lkml.kernel.org/r/20250226153614.3774896-1-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a58f3dcf

mm/page-writeback.c

+1 −0
Original line number Diff line number Diff line
@@ -3109,6 +3109,7 @@ void __folio_start_writeback(struct folio *folio, bool keep_write) 
	int access_ret;



	VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio);

	VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);



	if (mapping && mapping_use_writeback_tags(mapping)) {

		XA_STATE(xas, &mapping->i_pages, folio_index(folio));