From nobody Mon Feb 9 06:34:52 2026 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5B3FD2FDC5C; Fri, 30 Jan 2026 03:13:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769742806; cv=pass; b=sEMoPeX+Dg6scb7X6MJjmNRmh7ZGldj7/GQ1sTHfGcmIX1toHpf4ohZjEwx9MRLQpCqr9gP1B6iSnfvp+HDu7XwzF5c6pq/UM+DeIWLPQp0FWifU1F0/bre2p9cv6+Bd6dmyCqnAMpVSlkpAQPZDnXQ0MloP9aUDBNx3niWU4ZY= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769742806; c=relaxed/simple; bh=j/7YFkVlx9cqucXzcCMuVijXkSl7DCvIHMyg6bKq/Rg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NExq14ZRfsYyL1YuQonHlEKu+J6yDVwFg+w3emWEGqEOZik36PkxSdU5wHnjd4S4mQ0PWjm7k0zvEl/+zIXAhj45UaDZPW/OivPLvBvVw6uCwZrlrJGQT1Qc9o5+eHu567P8f4SKMbQv3Ck072Yhyf9cMCMBRkBOxxc0czv5Y/g= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=linux.beauty; spf=pass smtp.mailfrom=linux.beauty; dkim=pass (1024-bit key) header.d=linux.beauty header.i=me@linux.beauty header.b=RC0Gvuh4; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=linux.beauty Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.beauty Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.beauty header.i=me@linux.beauty header.b="RC0Gvuh4" ARC-Seal: i=1; a=rsa-sha256; t=1769742780; cv=none; d=zohomail.com; s=zohoarc; b=Uy540XI0jTOgxnBzThN7hEL1F8VkpkpGY4ZMGEwvTGxBDKL9DoFG66nM/1ltiSjfjXE06Vho58d0MjqDiwN7GJ18FdgdTMsE8aioBbIiHY9FJiKbiBcHEudO8E+TGN/IG5x3K4GvArT5Pld0hjj9jij75IpaeQml4FBZ0Hd8Cso= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1769742780; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=avd/AUZNm7D9+j9YRkdHx4VzxdkkFbvm2wfnuocDPVo=; b=DBQdyvAU+x6sQtJWDPSOIpn36jh2HQGRhObqgLCGbYQZwYa+k+UvF4JQeCeDdOvXBmINr2w/b93/TkbQ0bm/4hHZ9O+GXxazdVA9vYdWVyACnsIMSjjWH0uZxnYzVU2sqNDYgwasfFKEV+rn2mWnS9WMkFfoQc2gRgzJiOCZhjM= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=linux.beauty; spf=pass smtp.mailfrom=me@linux.beauty; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1769742780; s=zmail; d=linux.beauty; i=me@linux.beauty; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=avd/AUZNm7D9+j9YRkdHx4VzxdkkFbvm2wfnuocDPVo=; b=RC0Gvuh4MNWJZfwXsVBH5PbnA51XJddqMxkpo1mLYHfHRsbOTNmOnoFjkJ65AkIT sHsYaaCOe3tF+qlaZgDLq4vVk6x1b9CTD9UWno5GJ3qKNf4tmkuEago/cj8BmSOgFiV 7Fn2GjQh8BX5yXOlUGJ8CBCI157pQloE3z8qP3Kg= Received: by mx.zohomail.com with SMTPS id 1769742774598265.0356064896463; Thu, 29 Jan 2026 19:12:54 -0800 (PST) From: Li Chen To: "Theodore Ts'o" , Andreas Dilger , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jan Kara , Li Chen Subject: [PATCH 2/3] ext4: use READ_ONCE for lockless jinode reads Date: Fri, 30 Jan 2026 11:12:31 +0800 Message-ID: <20260130031232.60780-3-me@linux.beauty> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260130031232.60780-1-me@linux.beauty> References: <20260130031232.60780-1-me@linux.beauty> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMailClient: External Content-Type: text/plain; charset="utf-8" ext4 journal commit callbacks access jbd2_inode fields such as i_transaction and i_dirty_start/end without holding journal->j_list_lock. Use READ_ONCE() for these reads to correct the concurrency assumptions. Suggested-by: Jan Kara Signed-off-by: Li Chen Reviewed-by: Jan Kara --- fs/ext4/inode.c | 6 ++++-- fs/ext4/super.c | 13 ++++++++----- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index d99296d7315f..2d451388e080 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3033,11 +3033,13 @@ static int ext4_writepages(struct address_space *ma= pping, =20 int ext4_normal_submit_inode_data_buffers(struct jbd2_inode *jinode) { + loff_t dirty_start =3D READ_ONCE(jinode->i_dirty_start); + loff_t dirty_end =3D READ_ONCE(jinode->i_dirty_end); struct writeback_control wbc =3D { .sync_mode =3D WB_SYNC_ALL, .nr_to_write =3D LONG_MAX, - .range_start =3D jinode->i_dirty_start, - .range_end =3D jinode->i_dirty_end, + .range_start =3D dirty_start, + .range_end =3D dirty_end, }; struct mpage_da_data mpd =3D { .inode =3D jinode->i_vfs_inode, diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 5cf6c2b54bbb..acb2bc016fd4 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -521,6 +521,7 @@ static bool ext4_journalled_writepage_needs_redirty(str= uct jbd2_inode *jinode, { struct buffer_head *bh, *head; struct journal_head *jh; + transaction_t *trans =3D READ_ONCE(jinode->i_transaction); =20 bh =3D head =3D folio_buffers(folio); do { @@ -539,7 +540,7 @@ static bool ext4_journalled_writepage_needs_redirty(str= uct jbd2_inode *jinode, */ jh =3D bh2jh(bh); if (buffer_dirty(bh) || - (jh && (jh->b_transaction !=3D jinode->i_transaction || + (jh && (jh->b_transaction !=3D trans || jh->b_next_transaction))) return true; } while ((bh =3D bh->b_this_page) !=3D head); @@ -550,12 +551,14 @@ static bool ext4_journalled_writepage_needs_redirty(s= truct jbd2_inode *jinode, static int ext4_journalled_submit_inode_data_buffers(struct jbd2_inode *ji= node) { struct address_space *mapping =3D jinode->i_vfs_inode->i_mapping; + loff_t dirty_start =3D READ_ONCE(jinode->i_dirty_start); + loff_t dirty_end =3D READ_ONCE(jinode->i_dirty_end); struct writeback_control wbc =3D { - .sync_mode =3D WB_SYNC_ALL, + .sync_mode =3D WB_SYNC_ALL, .nr_to_write =3D LONG_MAX, - .range_start =3D jinode->i_dirty_start, - .range_end =3D jinode->i_dirty_end, - }; + .range_start =3D dirty_start, + .range_end =3D dirty_end, + }; struct folio *folio =3D NULL; int error; =20 --=20 2.52.0