Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
To:     Theodore Ts'o <tytso@mit.edu>
Cc:     linux-ext4@vger.kernel.org
References: <015c7506-7f33-3967-772a-1285b0f1052f@valdikss.org.ru>
 <YRCKG1V/OBuble40@mit.edu>
 <c984528b-03ce-f9e5-2cf2-4ae92e812367@valdikss.org.ru>
 <YRFzWGkBOHcugxGD@mit.edu>
From:   ValdikSS <iam@valdikss.org.ru>
Subject: Re: ext4lazyinit reads HDD data on mount since 5.13
Message-ID: <80f2ab1e-affb-5f31-e367-3f92b61d8ad9@valdikss.org.ru>
Date:   Mon, 9 Aug 2021 22:34:37 +0300
User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.5.0) Gecko/20100101,
 Thunderbird/78.5.0
MIME-Version: 1.0
In-Reply-To: <YRFzWGkBOHcugxGD@mit.edu>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 09.08.2021 21:26, Theodore Ts'o wrote:
> 
> It's not been tested, but it should be safe in terms that it shouldn't
> lead to any file system corruption or data loss.  However, it may
> result in non-optional block placement that might cause more file or
> free-space fragmentation that might otherwise be the case.  (This was
> true even before the latest optimizations, but it's more the case with
> the new optimizations.)
> 
> Can you say something about why you want to disable to block
> allocation prefetch?  How is it causing problems for you?

My old HDDs are now screeching their heads for 20 seconds after mount. 
That's secondary disks (internal and external drives) which are not 
fragmented, mostly idle and have plenty of free space. It's a bit 
annoying to hear the sounds and see strange load right after mounting, 
so I'd prefer old behavior.
Just aesthetics, not a technical issue per se.