From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.5]) (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 49056364EB8; Mon, 28 Sep 2026 08:54:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790585672; cv=none; b=ctkSp6IKs7hLxb82pe25QJPQxUwqVxy8m8f8YT13Yq4aIMPtHtYcJt9p7V4CgRuWGJfjHsDAWY34zF6ZsZRbLKbjYwPQpqYw5bm+he1YcvZRBBMj2ld6lDTnReQpvBjNUMnHTD3vzxai5a+NyA3T/6O1DRMj/hRSUNO1xE3OeA4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790585672; c=relaxed/simple; bh=5gW3H/1yVOxL00jh4JY44hYMcfiOVXML9SuZIS61MNk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=hvzgU6faaa5B0gYuH5v7qannbCLH5kY7a2ErO1ZX3Iv7n6ZS28uIVCp4tn57pBVHij08bk/Nys1wY2A2gE8sCsP8TuN8K0JEVJEtYtoX9Z/8KRa5e3XBgMb6re2GmyGjzI7MuvZpbAqbT1/ugYhOaJFfW6AK2/uIMwTAMib99xM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=AkuKIMfe; arc=none smtp.client-ip=220.197.31.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="AkuKIMfe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=2C SflERWiIEUtHIYwYt7AZ8Vjsf1CeCsPdvuomIllHU=; b=AkuKIMfefAeDzcrSzh K97jzq9oF0lcUjL5stJxR7APUWu9D5/bXjOIYFkvjxbC/hALlrPLMXC2UlF0bO76 VJQAZO3uKRFaPW12b/JxpyulpHnFvig5Mm7SX6jjLSgmkYcKC8sQx3/zXPsvhfHF 4BtmbrKvqcNJofkccWvVl1pmQ= Received: from pc.localdomain (unknown []) by gzga-smtp-mtada-g0-0 (Coremail) with SMTP id _____wD3t582K7pqm5HnBA--.52401S3; Mon, 28 Sep 2026 16:54:16 +0800 (CST) From: Jiale Yao To: Jan Kara , "Ritesh Harjani (IBM)" , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jiale Yao Subject: [PATCH v3 1/3] ext2: drain in-flight DIO before buffered write fallback Date: Mon, 28 Sep 2026 16:54:10 +0800 Message-Id: <20260928085412.2221055-2-yaojiale02@163.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260928085412.2221055-1-yaojiale02@163.com> References: <20260928085412.2221055-1-yaojiale02@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wD3t582K7pqm5HnBA--.52401S3 X-Coremail-Antispam: 1Uf129KBjvJXoW7tFyUuryxtFyDXr47tF1DJrb_yoW8Zrykpr Z093W5JryqyrZ7Wwn7Wa18ur1fK398ArW3XrWvv3WDCry5Gws0gF4ktr1jvF1fGFsrJw4Y qan29r97u3W0yaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zinYFJUUUUU= X-CM-SenderInfo: x1dryxhdohiji6rwjhhfrp/xtbCzhkiXGq6KzmQFAAA3v An asynchronous direct write can remain in flight after the inode lock is released. If another direct write falls back to buffered I/O while the first write is still pending, generic_perform_write() can dirty pages before the first write completes its post-I/O page cache invalidation. The invalidation then finds dirty pages, reports a page cache invalidation failure, and records -EIO in the mapping error sequence. A later fsync() therefore returns -EIO. Commit 15cdefd0c0522f9d5e12d947fa04f4c11649b699 ("ext4: drain in-flight DIO before buffered write fallback") fixed the same race in ext4. Ext2 has an equivalent fallback after iomap_dio_rw() returns -ENOTBLK or a short write, but does not drain other in-flight DIO before dirtying the page cache. Wait for in-flight DIO before calling generic_perform_write() in the fallback path. A reproducer using concurrent AIO direct writes and buffered fallback triggered the following warning and made a subsequent fsync() return -EIO: Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O! Fixes: fb5de4358e1a ("ext2: Move direct-io to use iomap") Link: https://lore.kernel.org/r/20260629113827.4074335-3-libaokun@linux.alibaba.com Signed-off-by: Jiale Yao --- fs/ext2/file.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/ext2/file.c b/fs/ext2/file.c index b9020df7d89e..67fe423c3828 100644 --- a/fs/ext2/file.c +++ b/fs/ext2/file.c @@ -135,6 +135,13 @@ static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) int ret2; iocb->ki_flags &= ~IOCB_DIRECT; + + /* + * Prevent concurrent direct I/O and buffered I/O to the same file + * range. Wait for in-flight DIO to finish before dirtying pages. + */ + inode_dio_wait(inode); + pos = iocb->ki_pos; status = generic_perform_write(iocb, from); if (unlikely(status < 0)) { -- 2.34.1