From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F41BC433EF for ; Thu, 23 Sep 2021 02:37:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC5BD60F70 for ; Thu, 23 Sep 2021 02:37:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238899AbhIWCjR (ORCPT ); Wed, 22 Sep 2021 22:39:17 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:25318 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238859AbhIWCjR (ORCPT ); Wed, 22 Sep 2021 22:39:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632364666; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=ABiN1/rr46NBTE/MYp4WucHHrl7YR7Bbsi69wTtcSFM=; b=XAS0UhW0LOIzRK+dnAW5WVgkvAUgxTNk6tKh8GucsIR3vnIlKKX0TE7St7huiisaPhPqON XnFIIAuBwQNEtWEmBDaK9y70ga12G4RaXagY0zXBUAtymfhBqnERl6TRXyGRCWXGrQLbhy OQLfWBBV8yENCH+8idCJcgNQhgPf89Y= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-593-DYbtqsSPMd2e7tH_E81cFQ-1; Wed, 22 Sep 2021 22:37:44 -0400 X-MC-Unique: DYbtqsSPMd2e7tH_E81cFQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 93E11801E72; Thu, 23 Sep 2021 02:37:43 +0000 (UTC) Received: from localhost (ovpn-8-17.pek2.redhat.com [10.72.8.17]) by smtp.corp.redhat.com (Postfix) with ESMTP id C64A360C2B; Thu, 23 Sep 2021 02:37:38 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Ming Lei , Jan Kara Subject: [PATCH V2] block: hold ->invalidate_lock in blkdev_fallocate Date: Thu, 23 Sep 2021 10:37:51 +0800 Message-Id: <20210923023751.1441091-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org When running ->fallocate(), blkdev_fallocate() should hold mapping->invalidate_lock to prevent page cache from being accessed, otherwise stale data may be read in page cache. Without this patch, blktests block/009 fails sometimes. With this patch, block/009 can pass always. Also as Jan pointed out, no pages can be created in the discarded area while you are holding the invalidate_lock, so remove the 2nd truncate_bdev_range(). Cc: Jan Kara Signed-off-by: Ming Lei --- V2: - include for avoiding implicit declaration of function filemap_invalidate_lock - remove 2nd truncate_bdev_range() as suggested by Jan block/fops.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/block/fops.c b/block/fops.c index ffce6f6c68dd..1e970c247e0e 100644 --- a/block/fops.c +++ b/block/fops.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "blk.h" static struct inode *bdev_file_inode(struct file *file) @@ -553,7 +554,8 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) static long blkdev_fallocate(struct file *file, int mode, loff_t start, loff_t len) { - struct block_device *bdev = I_BDEV(bdev_file_inode(file)); + struct inode *inode = bdev_file_inode(file); + struct block_device *bdev = I_BDEV(inode); loff_t end = start + len - 1; loff_t isize; int error; @@ -580,10 +582,12 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start, if ((start | len) & (bdev_logical_block_size(bdev) - 1)) return -EINVAL; + filemap_invalidate_lock(inode->i_mapping); + /* Invalidate the page cache, including dirty pages. */ error = truncate_bdev_range(bdev, file->f_mode, start, end); if (error) - return error; + goto fail; switch (mode) { case FALLOC_FL_ZERO_RANGE: @@ -600,17 +604,12 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start, GFP_KERNEL, 0); break; default: - return -EOPNOTSUPP; + error = -EOPNOTSUPP; } - if (error) - return error; - /* - * Invalidate the page cache again; if someone wandered in and dirtied - * a page, we just discard it - userspace has no way of knowing whether - * the write happened before or after discard completing... - */ - return truncate_bdev_range(bdev, file->f_mode, start, end); + fail: + filemap_invalidate_unlock(inode->i_mapping); + return error; } const struct file_operations def_blk_fops = { -- 2.31.1