The patch titled
Subject: writeback: don't call mapping_set_error on AOP_WRITEPAGE_ACTIVATE
has been added to the -mm mm-unstable branch. Its filename is
writeback-dont-call-mapping_set_error-on-aop_writepage_activate.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/writeback-dont-call-mapping_set_error-on-aop_writepage_activate.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: writeback: don't call mapping_set_error on AOP_WRITEPAGE_ACTIVATE
Date: Thu, 15 Feb 2024 07:36:36 +0100
Patch series "convert write_cache_pages() to an iterator", v8.
This is an evolution of the series Matthew Wilcox originally sent in June
2023, which has changed quite a bit since and now has a while based
iterator.
This patch (of 14):
mapping_set_error should only be called on 0 returns (which it ignores) or
a negative error code.
writepage_cb ends up being able to call writepage_cb on the magic
AOP_WRITEPAGE_ACTIVATE return value from ->writepage which means success
but the caller needs to unlock the page. Ignore that and just call
mapping_set_error on negative errors.
(no fixes tag as this goes back more than 20 years over various renames
and refactors so I've given up chasing down the original introduction)
Link: https://lkml.kernel.org/r/20240215063649.2164017-1-hch@xxxxxx
Link: https://lkml.kernel.org/r/20240215063649.2164017-2-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Dave Chinner <dchinner@xxxxxxxxxx>
Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page-writeback.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/page-writeback.c~writeback-dont-call-mapping_set_error-on-aop_writepage_activate
+++ a/mm/page-writeback.c
@@ -2535,7 +2535,9 @@ static int writepage_cb(struct folio *fo
{
struct address_space *mapping = data;
int ret = mapping->a_ops->writepage(&folio->page, wbc);
- mapping_set_error(mapping, ret);
+
+ if (ret < 0)
+ mapping_set_error(mapping, ret);
return ret;
}
_
Patches currently in -mm which might be from hch@xxxxxx are
writeback-dont-call-mapping_set_error-on-aop_writepage_activate.patch
writeback-fix-done_index-when-hitting-the-wbc-nr_to_write.patch
writeback-also-update-wbc-nr_to_write-on-writeback-failure.patch
writeback-only-update-writeback_index-for-range_cyclic-writeback.patch
writeback-rework-the-loop-termination-condition-in-write_cache_pages.patch
writeback-add-a-writeback-iterator.patch
