From nobody Mon Feb 9 01:46:24 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 4EDF4335564; Fri, 30 Jan 2026 03:13:19 +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=1769742800; cv=pass; b=Vh8TgrgeVKU7IRMmVRlwg+HH0gAhbXXfksqblShC08RFeLqUqf58c1gzVoeI9EyEMlhMI5zkKREwIRqqb30kSWrfEEALVhXbhKaKWGrfEfN/hX44keOBkPxsMIrJeOfHQ9Y4+K70ApovIz6o8GkI34c1KerO8YN4VjAUml7xHlY= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769742800; c=relaxed/simple; bh=Ih/Yu+mlwJPfIPjUeTHwNZR8KkUMEJ4helas/CIo8IA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MY+g5R+1CHP2GXqHfxxVmEP5GQO22GYPclarn0w2c0aSB5LKhHeyG/9/AWEh024MTHMT1BlX8kJ+sVdLNGaBb/geOyflsd0LRwg1tVZUPdsMdgBsjnDptjTlq5nVFzNg1REr5aFOMT4W8nMEQuAPwyMM6DjGwBP6RSfwX6UyGPg= 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=BqtTZLPG; 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="BqtTZLPG" ARC-Seal: i=1; a=rsa-sha256; t=1769742778; cv=none; d=zohomail.com; s=zohoarc; b=nv9ZtKaTMdQmEPld7A9ErB8HHEuiTYR5t7viN9zbFwNuXEXXpqp5ZOEaeSpau37WiN1oK70/2d34mT7pB8U4sS3Dtut+UiAi+Q7ld111HP+QacEgmt/3n+SKNRVU+RmWpJrpOGrzIFUQrJIvF63N4KsNgMKtUxiCFuP6Vr57X9g= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1769742778; 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=flqovzkqjGriKlWs8tgUbIAnm7IIBuluTOQuNQzOASc=; b=HPCoxWPB+TsgyIVmKsbFzUfjcUiH+Kn43z8YGG7OHLswiztiC97GN3L+zSI+EggvalBiRLsyKszWaleNStEfwETEI/3tVv9YRrqWQUxVw0/Br1zX0m10iI1PUsb5UkAPqfhslxkL6rsGSIg+2lr6O3Pui7IEfaCLXwmKRX17as8= 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=1769742778; 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=flqovzkqjGriKlWs8tgUbIAnm7IIBuluTOQuNQzOASc=; b=BqtTZLPGaO5claLf1CBC1TambgYd8F3h8P56GlMmGLJcq6b5imWkesdGx0jGaDJb B44F0NSTlmS3mUgA7+nufY5xhfo1i9uKeG1pjCCksNr53TY6Et/ol2o+6uOuFr4T4zt xcw/CHiJO5o5mFlRgcIFy5RbUrmuEasOTjwinXQw= Received: by mx.zohomail.com with SMTPS id 1769742772159561.7457286538283; Thu, 29 Jan 2026 19:12:52 -0800 (PST) From: Li Chen To: "Theodore Ts'o" , Jan Kara , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Li Chen Subject: [PATCH 1/3] jbd2: use READ_ONCE for lockless jinode reads Date: Fri, 30 Jan 2026 11:12:30 +0800 Message-ID: <20260130031232.60780-2-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" jbd2_inode fields are updated under journal->j_list_lock, but some paths read them without holding the lock (e.g. fast commit helpers and the ordered truncate fast path). Use READ_ONCE() for these lockless reads to correct the concurrency assumptions. Suggested-by: Jan Kara Signed-off-by: Li Chen Reviewed-by: Jan Kara --- fs/jbd2/commit.c | 39 ++++++++++++++++++++++++++++++++------- fs/jbd2/transaction.c | 2 +- 2 files changed, 33 insertions(+), 8 deletions(-) diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 7203d2d2624d..3347d75da2f8 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -180,7 +180,13 @@ static int journal_wait_on_commit_record(journal_t *jo= urnal, /* Send all the data buffers related to an inode */ int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode) { - if (!jinode || !(jinode->i_flags & JI_WRITE_DATA)) + unsigned long flags; + + if (!jinode) + return 0; + + flags =3D READ_ONCE(jinode->i_flags); + if (!(flags & JI_WRITE_DATA)) return 0; =20 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); @@ -191,12 +197,30 @@ EXPORT_SYMBOL(jbd2_submit_inode_data); =20 int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode) { - if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) || - !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping) + struct address_space *mapping; + struct inode *inode; + unsigned long flags; + loff_t start, end; + + if (!jinode) + return 0; + + flags =3D READ_ONCE(jinode->i_flags); + if (!(flags & JI_WAIT_DATA)) + return 0; + + inode =3D READ_ONCE(jinode->i_vfs_inode); + if (!inode) + return 0; + + mapping =3D inode->i_mapping; + start =3D READ_ONCE(jinode->i_dirty_start); + end =3D READ_ONCE(jinode->i_dirty_end); + + if (!mapping) return 0; return filemap_fdatawait_range_keep_errors( - jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start, - jinode->i_dirty_end); + mapping, start, end); } EXPORT_SYMBOL(jbd2_wait_inode_data); =20 @@ -240,10 +264,11 @@ static int journal_submit_data_buffers(journal_t *jou= rnal, int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode) { struct address_space *mapping =3D jinode->i_vfs_inode->i_mapping; + loff_t start =3D READ_ONCE(jinode->i_dirty_start); + loff_t end =3D READ_ONCE(jinode->i_dirty_end); =20 return filemap_fdatawait_range_keep_errors(mapping, - jinode->i_dirty_start, - jinode->i_dirty_end); + start, end); } =20 /* diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index dca4b5d8aaaa..302b2090eea7 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -2739,7 +2739,7 @@ int jbd2_journal_begin_ordered_truncate(journal_t *jo= urnal, int ret =3D 0; =20 /* This is a quick check to avoid locking if not necessary */ - if (!jinode->i_transaction) + if (!READ_ONCE(jinode->i_transaction)) goto out; /* Locks are here just to force reading of recent values, it is * enough that the transaction was not committing before we started --=20 2.52.0