This is a note to let you know that I've just added the patch titled
mm: do not reclaim private data from pinned page
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-do-not-reclaim-private-data-from-pinned-page.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d824ec2a154677f63c56cc71ffe4578274f6e32e Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@xxxxxxx>
Date: Fri, 28 Apr 2023 14:41:40 +0200
Subject: mm: do not reclaim private data from pinned page
From: Jan Kara <jack@xxxxxxx>
commit d824ec2a154677f63c56cc71ffe4578274f6e32e upstream.
If the page is pinned, there's no point in trying to reclaim it.
Furthermore if the page is from the page cache we don't want to reclaim
fs-private data from the page because the pinning process may be writing
to the page at any time and reclaiming fs private info on a dirty page can
upset the filesystem (see link below).
Link: https://lore.kernel.org/linux-mm/20180103100430.GE4911@xxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20230428124140.30166-1-jack@xxxxxxx
Signed-off-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1887,6 +1887,16 @@ retry:
}
}
+ /*
+ * Folio is unmapped now so it cannot be newly pinned anymore.
+ * No point in trying to reclaim folio if it is pinned.
+ * Furthermore we don't want to reclaim underlying fs metadata
+ * if the folio is pinned and thus potentially modified by the
+ * pinning process as that may upset the filesystem.
+ */
+ if (folio_maybe_dma_pinned(folio))
+ goto activate_locked;
+
mapping = folio_mapping(folio);
if (folio_test_dirty(folio)) {
/*
Patches currently in stable-queue which might be from jack@xxxxxxx are
queue-6.1/ext4-fix-i_disksize-exceeding-i_size-problem-in-pari.patch
queue-6.1/ext4-fix-use-after-free-read-in-ext4_find_extent-for.patch
queue-6.1/jdb2-don-t-refuse-invalidation-of-already-invalidate.patch
queue-6.1/mm-do-not-reclaim-private-data-from-pinned-page.patch
