From patchwork Tue Aug 25 12:05:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 11735631 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3F21517C7 for ; Tue, 25 Aug 2020 12:06:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 317052074A for ; Tue, 25 Aug 2020 12:06:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729425AbgHYMGI (ORCPT ); Tue, 25 Aug 2020 08:06:08 -0400 Received: from mx2.suse.de ([195.135.220.15]:42078 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729131AbgHYMGF (ORCPT ); Tue, 25 Aug 2020 08:06:05 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 8430FACDF; Tue, 25 Aug 2020 12:06:34 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 1E91E1E1319; Tue, 25 Aug 2020 14:05:59 +0200 (CEST) From: Jan Kara To: Cc: yebin , Christoph Hellwig , , Jens Axboe , Jan Kara Subject: [PATCH RFC 2/2] block: Do not discard buffers under a mounted filesystem Date: Tue, 25 Aug 2020 14:05:54 +0200 Message-Id: <20200825120554.13070-3-jack@suse.cz> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200825120554.13070-1-jack@suse.cz> References: <20200825120554.13070-1-jack@suse.cz> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Discarding blocks and buffers under a mounted filesystem is hardly anything admin wants to do. Usually it will confuse the filesystem and sometimes the loss of buffer_head state (including b_private field) can even cause crashes like: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 PGD 0 P4D 0 Oops: 0002 [#1] SMP PTI CPU: 4 PID: 203778 Comm: jbd2/dm-3-8 Kdump: loaded Tainted: G O --------- - - 4.18.0-147.5.0.5.h126.eulerosv2r9.x86_64 #1 Hardware name: Huawei RH2288H V3/BC11HGSA0, BIOS 1.57 08/11/2015 RIP: 0010:jbd2_journal_grab_journal_head+0x1b/0x40 [jbd2] ... Call Trace: __jbd2_journal_insert_checkpoint+0x23/0x70 [jbd2] jbd2_journal_commit_transaction+0x155f/0x1b60 [jbd2] kjournald2+0xbd/0x270 [jbd2] So refuse fallocate(2) and BLKZEROOUT, BLKDISCARD, BLKSECDISCARD ioctls for a block device having filesystem mounted. Reported-by: Ye Bin Signed-off-by: Jan Kara --- block/ioctl.c | 19 ++++++++++++++++++- fs/block_dev.c | 9 +++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/block/ioctl.c b/block/ioctl.c index bdb3bbb253d9..0e3a46b0ffc8 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -113,7 +113,7 @@ static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode, uint64_t start, len; struct request_queue *q = bdev_get_queue(bdev); struct address_space *mapping = bdev->bd_inode->i_mapping; - + struct super_block *sb; if (!(mode & FMODE_WRITE)) return -EBADF; @@ -134,6 +134,14 @@ static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode, if (start + len > i_size_read(bdev->bd_inode)) return -EINVAL; + /* + * Don't mess with device with mounted filesystem. + */ + sb = get_super(bdev); + if (sb) { + drop_super(sb); + return -EBUSY; + } truncate_inode_pages_range(mapping, start, start + len - 1); return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL, flags); @@ -145,6 +153,7 @@ static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode, uint64_t range[2]; struct address_space *mapping; uint64_t start, end, len; + struct super_block *sb; if (!(mode & FMODE_WRITE)) return -EBADF; @@ -165,6 +174,14 @@ static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode, if (end < start) return -EINVAL; + /* + * Don't mess with device with mounted filesystem. + */ + sb = get_super(bdev); + if (sb) { + drop_super(sb); + return -EBUSY; + } /* Invalidate the page cache, including dirty pages */ mapping = bdev->bd_inode->i_mapping; truncate_inode_pages_range(mapping, start, end); diff --git a/fs/block_dev.c b/fs/block_dev.c index 8ae833e00443..5b398eb7c34c 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1973,6 +1973,7 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start, loff_t end = start + len - 1; loff_t isize; int error; + struct super_block *sb; /* Fail if we don't recognize the flags. */ if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) @@ -1996,6 +1997,14 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start, if ((start | len) & (bdev_logical_block_size(bdev) - 1)) return -EINVAL; + /* + * Don't mess with device with mounted filesystem. + */ + sb = get_super(bdev); + if (sb) { + drop_super(sb); + return -EBUSY; + } /* Invalidate the page cache, including dirty pages. */ mapping = bdev->bd_inode->i_mapping; truncate_inode_pages_range(mapping, start, end);