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Message-ID: <4a818d7e-bddd-f44c-d115-a7e81301983a@kernel.org>
Date:   Fri, 3 Feb 2023 16:54:18 +0800
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Subject: Re: [f2fs-dev] [PATCH] f2fs: fix cgroup writeback accounting with
 fs-layer encryption
Content-Language: en-US
To:     Eric Biggers <ebiggers@kernel.org>,
        linux-f2fs-devel@lists.sourceforge.net
Cc:     stable@vger.kernel.org, Tejun Heo <tj@kernel.org>,
        linux-fscrypt@vger.kernel.org,
        Matthew Wilcox <willy@infradead.org>,
        linux-fsdevel@vger.kernel.org
References: <20230203010239.216421-1-ebiggers@kernel.org>
From:   Chao Yu <chao@kernel.org>
In-Reply-To: <20230203010239.216421-1-ebiggers@kernel.org>
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On 2023/2/3 9:02, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> When writing a page from an encrypted file that is using
> filesystem-layer encryption (not inline encryption), f2fs encrypts the
> pagecache page into a bounce page, then writes the bounce page.
> 
> It also passes the bounce page to wbc_account_cgroup_owner().  That's
> incorrect, because the bounce page is a newly allocated temporary page
> that doesn't have the memory cgroup of the original pagecache page.
> This makes wbc_account_cgroup_owner() not account the I/O to the owner
> of the pagecache page as it should.
> 
> Fix this by always passing the pagecache page to
> wbc_account_cgroup_owner().
> 
> Fixes: 578c647879f7 ("f2fs: implement cgroup writeback support")
> Cc: stable@vger.kernel.org
> Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,