+ mm-cleancache-fix-corruption-on-missed-inode-invalidation.patch added to -mm tree

+ mm-cleancache-fix-corruption-on-missed-inode-invalidation.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: cleancache: fix corruption on missed inode invalidation
has been added to the -mm tree.  Its filename is
     mm-cleancache-fix-corruption-on-missed-inode-invalidation.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-cleancache-fix-corruption-on-missed-inode-invalidation.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-cleancache-fix-corruption-on-missed-inode-invalidation.patch

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------------------------------------------------------
From: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Subject: 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.

Link: http://lkml.kernel.org/r/20181112095734.17979-1-ptikhomirov@virtuozzo.com
Fixes: commit 91b0abe36a7b ("mm + fs: store shadow entries in page cache")
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Reviewed-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/truncate.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/truncate.c~mm-cleancache-fix-corruption-on-missed-inode-invalidation
+++ a/mm/truncate.c
@@ -517,9 +517,9 @@ void truncate_inode_pages_final(struct a
 		 */
 		xa_lock_irq(&mapping->i_pages);
 		xa_unlock_irq(&mapping->i_pages);
-
-		truncate_inode_pages(mapping, 0);
 	}
+
+	truncate_inode_pages(mapping, 0);
 }
 EXPORT_SYMBOL(truncate_inode_pages_final);
 
_

Patches currently in -mm which might be from ptikhomirov@virtuozzo.com are

mm-cleancache-fix-corruption-on-missed-inode-invalidation.patch