From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Jenkins Subject: Re: [PATCH 31/34] vfs: syscall: Add fspick() to select a superblock for reconfiguration [ver #12] Date: Wed, 17 Oct 2018 15:31:26 +0100 Message-ID: References: <19866.1539782101@warthog.procyon.org.uk> <68a2107f-bf70-055b-86cf-1ba2ba9422bf@gmail.com> <153754740781.17872.7869536526927736855.stgit@warthog.procyon.org.uk> <153754766004.17872.9829232103614083565.stgit@warthog.procyon.org.uk> <9b8bf436-65de-13b9-0002-0479d11c18ca@gmail.com> <20181013061141.GR32577@ZenIV.linux.org.uk> <28710.1539782412@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <28710.1539782412@warthog.procyon.org.uk> Content-Language: en-GB Sender: linux-kernel-owner@vger.kernel.org To: David Howells Cc: Al Viro , linux-api@vger.kernel.org, torvalds@linux-foundation.org, ebiederm@xmission.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mszeredi@redhat.com List-Id: linux-api@vger.kernel.org On 17/10/2018 14:20, David Howells wrote: > David Howells wrote: > >> I should probably check that the picked point is actually a mountpoint. > The root of the mount object at the path specified, that is, perhaps with > something like the attached. > > David I agree.  I'm happy to see this is using the same check as do_remount(). * change filesystem flags. dir should be a physical root of filesystem. * If you've mounted a non-root directory somewhere and want to do remount * on it - tough luck. */ Thanks Alan > --- > diff --git a/fs/fsopen.c b/fs/fsopen.c > index f673e93ac456..aaaaa17a233c 100644 > --- a/fs/fsopen.c > +++ b/fs/fsopen.c > @@ -186,6 +186,10 @@ SYSCALL_DEFINE3(fspick, int, dfd, const char __user *, path, unsigned int, flags > if (ret < 0) > goto err; > > + ret = -EINVAL; > + if (target.mnt->mnt_root != target.dentry) > + goto err_path; > + > fc = vfs_new_fs_context(target.dentry->d_sb->s_type, target.dentry, > 0, 0, FS_CONTEXT_FOR_RECONFIGURE); > if (IS_ERR(fc)) { >