From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f179.google.com (mail-pf1-f179.google.com [209.85.210.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB2BB2581 for ; Mon, 12 Jun 2023 06:20:54 +0000 (UTC) Received: by mail-pf1-f179.google.com with SMTP id d2e1a72fcca58-655d1fc8ad8so3244689b3a.1 for ; Sun, 11 Jun 2023 23:20:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1686550854; x=1689142854; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=/JK3TU7YFRj/e68GIZTEHv4xrVfCyD4VBzaHU6EBRGQ=; b=aUa5nt3Z+69SyeNiK7yPDV0XLk7GzaJ1aQBLWuPOPiCkiHgSpgXDzPNOHeCh9WQ35P UnmhQvm7XbQ+BnkZ5dGabdJ294JCp/che7tA/nTi8LYdcg43Bdh3PIrYmU4HnfXeXVmP SEECUNPfPr/ykHDt06HStvFyW7V8em8Nd+0UvtAc/3TSZ0THzXUbVKVRUlsNZODhtFsE B+mIXMupQqcdg03n2AyO+emkN8tutn0xSdS3C/CSARL1xYniDF+n5IBpIS1NwRwtI0Gr Y2rwTzpuptPqwTV1S708H0LQUZLjrFtQ/XfO3w+BGpYDq67lLliKdvPxfd8Vinv/hEt9 CQHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686550854; x=1689142854; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=/JK3TU7YFRj/e68GIZTEHv4xrVfCyD4VBzaHU6EBRGQ=; b=koWznRY5pHoaxU9qBNQzei8U2CPOPlwR2icJfsGkgCmn0mxt4eliw0FfD5DNf2Bqut EYzyxO65fdQ1VXzUD6qom27yEGXoMJs5byYOv1WcaIMG02/P9305Ps3if0oBjMNAo5aX gXYK6lFB6pNJ5nmcslhmFWoY6LTWgTFOB+EOzs0hru85lPoWwyQ7cfu/exg7w/TOkOjW mAtzwVLe/xIaL/StD4TBG6DQ1lUPv4LiUhD1bBEto31GC+rt20s4spCMIXHSFtse0qaj nc7JZ8JzSNo4j7bSOVMrXwz5NE55Zoxj6h6Ss6KPdGV+nxfsIcfrjGitpVQ47rX4LiMn lVgA== X-Gm-Message-State: AC+VfDyNEMGyyaTGv1tXJRelyKSqhKkWcmsEpGSFcd0GRCXOyAwgGsu9 gGuDhuBDVmWTaS15uN3/yAk= X-Google-Smtp-Source: ACHHUZ47hq6fy+3dOE/9k3HLlR5J6NXUjY5+c8Xdb8hoek4U+8usGCZMz9GYBPy/DFFGlsARY+FkSA== X-Received: by 2002:a05:6a21:6da3:b0:10a:be5c:6e2d with SMTP id wl35-20020a056a216da300b0010abe5c6e2dmr9208618pzb.39.1686550854098; Sun, 11 Jun 2023 23:20:54 -0700 (PDT) Received: from debian.me ([103.124.138.155]) by smtp.gmail.com with ESMTPSA id c14-20020aa7880e000000b0063d46ec5777sm6162834pfo.158.2023.06.11.23.20.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 11 Jun 2023 23:20:53 -0700 (PDT) Received: by debian.me (Postfix, from userid 1000) id 4DE28106C10; Mon, 12 Jun 2023 13:20:48 +0700 (WIB) Date: Mon, 12 Jun 2023 13:20:47 +0700 From: Bagas Sanjaya To: Sean Greenslade , linux-ext4@vger.kernel.org, Ye Bin , Theodore Ts'o Cc: Linux Kernel Mailing List , Linux Regressions Subject: Re: RO mount of ext4 filesystem causes writes Message-ID: References: Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="oXjBG6aBq0cIy8y4" Content-Disposition: inline In-Reply-To: --oXjBG6aBq0cIy8y4 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Jun 11, 2023 at 10:32:53PM -0700, Sean Greenslade wrote: > Hello, folks. >=20 > I noticed a change in behavior of ext4 in recent kernels. I make use of > several luks loopback images formatted as ext4 that I mount read-only > most of the time. I use rsync to synchronize the backing images between > machines. In the past, mouning the images as read-only would not touch > the backing image contents at all, but recently this changed. Every > mount, even ones that are RO from the start, will cause some small > writes to the backing image and thus force rsync to scan the whole file. >=20 > I confirmed that the issue is still present on v6.4.rc6, so I performed > a bisect and landed on the following commit: >=20 > > eee00237fa5ec8f704f7323b54e48cc34e2d9168 is the first bad commit > > commit eee00237fa5ec8f704f7323b54e48cc34e2d9168 > > Author: Ye Bin > > Date: Tue Mar 7 14:17:02 2023 +0800 > >=20 > > ext4: commit super block if fs record error when journal record wit= hout error >=20 > That certainly looks like a likely cause of my issue, but I'm not > familiar enough with the ext4 code to diagnose any further. Please let > me know if you need any additional information, or if you would like me > to test anything. >=20 Can you show dmesg when regression happens? Ye: It looks like this regression is caused by your commit. Would you like to take a look on it? Anyway, thanks for the bug report. I'm adding it to regzbot: #regzbot ^introduced: eee00237fa5ec8 #regzbot title: commit super block writes even in read-only filesystems Thanks. --=20 An old man doll... just what I always wanted! - Clara --oXjBG6aBq0cIy8y4 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQSSYQ6Cy7oyFNCHrUH2uYlJVVFOowUCZIa5OAAKCRD2uYlJVVFO ow0cAQC7IbRS13IAEmBezzjzEsFelZvVP5CenQsOEP8upCcnJgD9F7Q7Prz3KHjS cfIlPECSx7tGH7s1tiQymT3LZ/C78w0= =/u+c -----END PGP SIGNATURE----- --oXjBG6aBq0cIy8y4--