Commit 29e9412b authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm/memory-failure: stop setting the folio error flag 

Nobody checks the error flag any more, so setting it accomplishes nothing.
Remove the obsolete parts of this comment; it hasn't been true since
errseq_t was used to track writeback errors in 2017.

Link: https://lkml.kernel.org/r/20240531032938.2712870-1-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarOscar Salvador <osalvador@suse.de>
Acked-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ba518f4d

mm/memory-failure.c

+0 −29
Original line number Diff line number Diff line
@@ -1112,7 +1112,6 @@ static int me_pagecache_dirty(struct page_state *ps, struct page *p) 
	struct folio *folio = page_folio(p);

	struct address_space *mapping = folio_mapping(folio);



	SetPageError(p);

	/* TBD: print more information about the file. */

	if (mapping) {

		/*
@@ -1120,34 +1119,6 @@ static int me_pagecache_dirty(struct page_state *ps, struct page *p) 
		 * who check the mapping.

		 * This way the application knows that something went

		 * wrong with its dirty file data.

		 *

		 * There's one open issue:

		 *

		 * The EIO will be only reported on the next IO

		 * operation and then cleared through the IO map.

		 * Normally Linux has two mechanisms to pass IO error

		 * first through the AS_EIO flag in the address space

		 * and then through the PageError flag in the page.

		 * Since we drop pages on memory failure handling the

		 * only mechanism open to use is through AS_AIO.

		 *

		 * This has the disadvantage that it gets cleared on

		 * the first operation that returns an error, while

		 * the PageError bit is more sticky and only cleared

		 * when the page is reread or dropped.  If an

		 * application assumes it will always get error on

		 * fsync, but does other operations on the fd before

		 * and the page is dropped between then the error

		 * will not be properly reported.

		 *

		 * This can already happen even without hwpoisoned

		 * pages: first on metadata IO errors (which only

		 * report through AS_EIO) or when the page is dropped

		 * at the wrong time.

		 *

		 * So right now we assume that the application DTRT on

		 * the first EIO, but we're not worse than other parts

		 * of the kernel.

		 */

		mapping_set_error(mapping, -EIO);

	}