Backported mainline commit 6ff38bd40230af35
("mm: cleancache: fix corruption on missed inode invalidation")
From: Pavel Tikhomirov <ptikhomirov@xxxxxxxxxxxxx>
Date: Fri, 30 Nov 2018 14:09:00 -0800
Subject: [PATCH] mm: cleancache: fix corruption on missed inode invalidation
If all pages are deleted from the mapping by memory reclaim and also
moved to the cleancache:
__delete_from_page_cache
(no shadow case)
unaccount_page_cache_page
cleancache_put_page
page_cache_delete
mapping->nrpages -= nr
(nrpages becomes 0)
We don't clean the cleancache for an inode after final file truncation
(removal).
truncate_inode_pages_final
check (nrpages || nrexceptional) is false
no truncate_inode_pages
no cleancache_invalidate_inode(mapping)
These way when reading the new file created with same inode we may get
these trash leftover pages from cleancache and see wrong data instead of
the contents of the new file.
Fix it by always doing truncate_inode_pages which is already ready for
nrpages == 0 && nrexceptional == 0 case and just invalidates inode.
[akpm@xxxxxxxxxxxxxxxxxxxx: add comment, per Jan]
Link: http://lkml.kernel.org/r/20181112095734.17979-1-ptikhomirov@xxxxxxxxxxxxx
Fixes: commit 91b0abe36a7b ("mm + fs: store shadow entries in page cache")
Signed-off-by: Pavel Tikhomirov <ptikhomirov@xxxxxxxxxxxxx>
Reviewed-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
---
mm/truncate.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/mm/truncate.c b/mm/truncate.c
index 2330223841fb..d3a2737cc188 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -471,9 +471,13 @@ void truncate_inode_pages_final(struct address_space *mapping)
*/
spin_lock_irq(&mapping->tree_lock);
spin_unlock_irq(&mapping->tree_lock);
-
- truncate_inode_pages(mapping, 0);
}
+
+ /*
+ * Cleancache needs notification even if there are no pages or shadow
+ * entries.
+ */
+ truncate_inode_pages(mapping, 0);
}
EXPORT_SYMBOL(truncate_inode_pages_final);
--
2.17.1
