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Date:   Thu, 15 Nov 2018 14:29:59 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Jan Kara <jack@suse.cz>
Cc:     Pavel Tikhomirov <ptikhomirov@virtuozzo.com>,
        Vasily Averin <vvs@virtuozzo.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Konstantin Khorenko <khorenko@virtuozzo.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Mel Gorman <mgorman@techsingularity.net>,
        Matthew Wilcox <willy@infradead.org>,
        Andi Kleen <ak@linux.intel.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: cleancache: fix corruption on missed inode
 invalidation
Message-Id: <20181115142959.89ecdb6b4f24a1427062d861@linux-foundation.org>
In-Reply-To: <20181112113153.GC7175@quack2.suse.cz>
References: <20181112095734.17979-1-ptikhomirov@virtuozzo.com>
        <20181112113153.GC7175@quack2.suse.cz>
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On Mon, 12 Nov 2018 12:31:53 +0100 Jan Kara <jack@suse.cz> wrote:

> >  mm/truncate.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> The patch looks good but can you add a short comment before the
> truncate_inode_pages() call explaining why it needs to be called always?
> Something like:
> 
> 	 /*
> 	  * Cleancache needs notification even if there are no pages or
> 	  * shadow entries...
> 	  */

--- a/mm/truncate.c~mm-cleancache-fix-corruption-on-missed-inode-invalidation-fix
+++ a/mm/truncate.c
@@ -519,6 +519,10 @@ void truncate_inode_pages_final(struct a
 		xa_unlock_irq(&mapping->i_pages);
 	}
 
+	/*
+	 * Cleancache needs notification even if there are no pages or shadow
+	 * entries.
+	 */
 	truncate_inode_pages(mapping, 0);
 }
 EXPORT_SYMBOL(truncate_inode_pages_final);
_