From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.4]) (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 522A338A73C for ; Sat, 26 Sep 2026 07:26:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790407613; cv=none; b=MdIoWz4747pGlsxciQCs80C0oWRz5ps+F7+kGTyMwCpNaDDvhPwl9gNtl6zMt1VHqPJdpY7PkENhvFXn0U0nnZjeMY8lBx1j2ezGKSDKHAjDGKyIXTXcP+ufFOwMW4036JI38zS/ucoSmLEIZ9MsUvDE15ZM6BnwRb4GQQPqZF4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790407613; c=relaxed/simple; bh=VCOUBmSvA08OLSZZ0QUtRpBpXc4RIeX5lNww1zeNj+w=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=pFfUV1hInKXnP+YiVlkTBcVgG6Mgg3u8U1AexXJSruZuUGFqRTJNeW1+sVwz0MlyDkwC006gq/za15kO5Z2ARBBO5jsqx7KA4BuOFw4UuobxPlvsG4h8IDx4C2Ge3SERC111/FZDpqN51d3dzucPcqoYpdUJg9CJXPc21qFLyFQ= 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=IfIfn20M; arc=none smtp.client-ip=220.197.31.4 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="IfIfn20M" 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=Gb iQVEWtVb+Jbk8/U09Tj0Cxmmbe6xVeYJInM/aCluU=; b=IfIfn20MO5DPeXFGaK TwPGlM2/noyA3Joho5XpvFM2yaOb3DdZyWQ9T/AAr3BMHIO8XcTYgYHxIU4tMUt3 Da1r2AhJOxBJ/LdFi/E2DY7inHL55WccLxvXqP3EL1TPH4pf30zrI37WR5oI181D r/sRUPYDChNNvpcxjKlg9XM0I= Received: from pc.localdomain (unknown []) by gzga-smtp-mtada-g1-3 (Coremail) with SMTP id _____wD3v62dc7dqbEDbAw--.41165S5; Sat, 26 Sep 2026 15:26:27 +0800 (CST) From: Jiale Yao To: Namjae Jeon , Sungjong Seo , Yuezhang Mo , "Darrick J. Wong" , exfat@lists.linux.dev, linux-kernel@vger.kernel.org Cc: Jiale Yao Subject: [PATCH v2 3/3] exfat: drain in-flight DIO before buffered write fallback Date: Sat, 26 Sep 2026 15:26:12 +0800 Message-Id: <20260926072612.3022680-4-yaojiale02@163.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260926072612.3022680-1-yaojiale02@163.com> References: <20260926072612.3022680-1-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:_____wD3v62dc7dqbEDbAw--.41165S5 X-Coremail-Antispam: 1Uf129KBjvJXoW7tF4kGFy5AFykKF47tr1rXrb_yoW8ZF43pr Z0ga45JryDt397XwnruF48W3WFk395A3y3ZrWvv3WDCrWUWr4vga1ktr1YvF43JanrGr4j qa109rykAr1DCaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zRW89_UUUUU= X-CM-SenderInfo: x1dryxhdohiji6rwjhhfrp/xtbCzgONx2q3c6O7KgAA3b 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, iomap_file_buffered_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. ExFAT 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 iomap_file_buffered_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: 867b9c96dc83 ("exfat: add iomap direct I/O support") Link: https://lore.kernel.org/r/20260629113827.4074335-3-libaokun@linux.alibaba.com Signed-off-by: Jiale Yao --- fs/exfat/file.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/exfat/file.c b/fs/exfat/file.c index a2a9ee1a2004..cf5ccbd54823 100644 --- a/fs/exfat/file.c +++ b/fs/exfat/file.c @@ -807,6 +807,12 @@ static ssize_t exfat_fallback_buffered_write(struct kiocb *iocb, 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(file_inode(iocb->ki_filp)); + written = iomap_file_buffered_write(iocb, from, &exfat_write_iomap_ops, NULL, NULL); if (written < 0) -- 2.34.1