From: Andrew Morton <akpm@linux-foundation.org>
To: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: 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>, Jan Kara <jack@suse.cz>,
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
Date: Thu, 15 Nov 2018 14:31:03 -0800 [thread overview]
Message-ID: <20181115143103.c6fa8fec343bb706b91f6c6c@linux-foundation.org> (raw)
In-Reply-To: <20181112095734.17979-1-ptikhomirov@virtuozzo.com>
On Mon, 12 Nov 2018 12:57:34 +0300 Pavel Tikhomirov <ptikhomirov@virtuozzo.com> wrote:
> 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.
>
Data corruption sounds serious. Shouldn't we backport this into
-stable kernels?
next prev parent reply other threads:[~2018-11-15 22:31 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-12 9:57 [PATCH] mm: cleancache: fix corruption on missed inode invalidation Pavel Tikhomirov
2018-11-12 11:31 ` Jan Kara
2018-11-12 11:40 ` Andrey Ryabinin
2018-11-12 11:54 ` Jan Kara
2018-11-12 12:00 ` [PATCH v2] " Pavel Tikhomirov
2018-11-15 22:29 ` [PATCH] " Andrew Morton
2018-11-15 22:31 ` Andrew Morton [this message]
2018-11-16 7:55 ` Vasily Averin
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