From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:51517 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932314AbcFCPnN (ORCPT ); Fri, 3 Jun 2016 11:43:13 -0400 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 250F3AC3D for ; Fri, 3 Jun 2016 15:43:12 +0000 (UTC) From: David Sterba To: stable@vger.kernel.org Subject: [PATCH 12/21] btrfs: add write protection to SET_FEATURES ioctl Date: Fri, 3 Jun 2016 17:42:33 +0200 Message-Id: <1464968553-6721-1-git-send-email-dsterba@suse.com> In-Reply-To: <20160603154006.GP29147@suse.cz> References: <20160603154006.GP29147@suse.cz> Sender: stable-owner@vger.kernel.org List-ID: From: David Sterba commit 7ab19625a911f7568ec85302e3aa7a64186006c8 upstream. Perform the want_write check if we get far enough to do any writes. Signed-off-by: David Sterba --- fs/btrfs/ioctl.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index ea21e588a839..14e291422ab1 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -5397,9 +5397,15 @@ static int btrfs_ioctl_set_features(struct file *file, void __user *arg) if (ret) return ret; + ret = mnt_want_write_file(file); + if (ret) + return ret; + trans = btrfs_start_transaction(root, 0); - if (IS_ERR(trans)) - return PTR_ERR(trans); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + goto out_drop_write; + } spin_lock(&root->fs_info->super_lock); newflags = btrfs_super_compat_flags(super_block); @@ -5418,7 +5424,11 @@ static int btrfs_ioctl_set_features(struct file *file, void __user *arg) btrfs_set_super_incompat_flags(super_block, newflags); spin_unlock(&root->fs_info->super_lock); - return btrfs_commit_transaction(trans, root); + ret = btrfs_commit_transaction(trans, root); +out_drop_write: + mnt_drop_write_file(file); + + return ret; } long btrfs_ioctl(struct file *file, unsigned int -- 2.7.1