From: Oleg Nesterov <oleg@redhat.com>
To: Alexey Gladkov <gladkov.alexey@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Vasiliy Kulikov <segoon@openwall.com>,
Al Viro <viro@zeniv.linux.org.uk>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Pavel Emelyanov <xemul@parallels.com>,
James Bottomley <James.Bottomley@HansenPartnership.com>
Subject: Re: [RFC] Add option to mount only a pids subset
Date: Tue, 7 Mar 2017 18:49:09 +0100 [thread overview]
Message-ID: <20170307174909.GA24112@redhat.com> (raw)
In-Reply-To: <20170306230515.GA3453@comp-core-i7-2640m-0182e6>
I can't really review this... but in any case I think you should split
this patch to separate the vfs and proc changes.
On 03/07, Alexey Gladkov wrote:
>
> @@ -962,6 +963,14 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
> mnt->mnt.mnt_sb = root->d_sb;
> mnt->mnt_mountpoint = mnt->mnt.mnt_root;
> mnt->mnt_parent = mnt;
> +
> + err = do_mount_sb(&mnt->mnt, flags, data);
> + if(err) {
> + mnt_free_id(mnt);
> + free_vfsmnt(mnt);
> + return ERR_PTR(err);
> + }
This duplicates the error handling, we do the same if mount_fs() fails.
Perhaps you should move these 2 lines into cleanup block and add goto's.
> +int proc_getattrfs(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
> +{
> + struct inode *inode = d_inode(dentry);
> + struct pid *pid = proc_pid(dentry->d_inode);
> + struct proc_options *opts = mnt->fs_data;
> +
> + if (opts && opts->pid_only && mnt->mnt_root != dentry && !pid)
> + return -ENOENT;
Hmm. I don't quite understand why do we need this, and how this should work.
Yes, "/bin/ls /pidonly-proc/sys" or opendir(/pidonly-proc/sys) should fail,
but only because they both do stat() ?
Afaics you still can do open("/pidonly-proc/sys") + getdents() and this should
work ?
I still think proc_dir_operations.open() makes more sense. Yes, as you pointed
out we also need to update proc_sys_dir_file_operations too and may be something
else...
> +
> + if (!inode->i_op->getattr) {
> + generic_fillattr(inode, stat);
> + return 0;
> + }
> +
> + return inode->i_op->getattr(mnt, dentry, stat);
> +}
Oh, it would be nice to not duplicate the code from the caller, imo.
Oleg.
next prev parent reply other threads:[~2017-03-07 17:52 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-18 22:53 [PATCH] Add pidfs filesystem Alexey Gladkov
2017-02-18 23:34 ` kbuild test robot
2017-02-18 23:34 ` kbuild test robot
2017-02-20 4:05 ` Eric W. Biederman
2017-02-20 10:36 ` Alexey Gladkov
2017-02-22 20:11 ` Richard Weinberger
2017-02-21 14:57 ` Oleg Nesterov
2017-02-22 7:40 ` Pavel Emelyanov
2017-02-22 12:04 ` Alexey Gladkov
2017-02-22 13:08 ` Pavel Emelyanov
2017-02-22 11:53 ` Alexey Gladkov
2017-02-22 15:37 ` Dmitry V. Levin
2017-02-22 17:48 ` Oleg Nesterov
2017-02-22 19:56 ` Alexey Gladkov
2017-03-06 23:05 ` [RFC] Add option to mount only a pids subset Alexey Gladkov
2017-03-07 16:24 ` Andy Lutomirski
2017-03-09 11:26 ` Djalal Harouni
2017-03-09 20:52 ` Eric W. Biederman
2017-03-11 21:51 ` Alexey Gladkov
2017-03-11 0:05 ` Alexey Gladkov
2017-03-07 17:49 ` Oleg Nesterov [this message]
2017-03-10 23:46 ` Alexey Gladkov
2017-03-12 1:54 ` Al Viro
2017-03-12 2:13 ` Al Viro
2017-03-13 3:19 ` Andy Lutomirski
2017-03-13 13:27 ` Al Viro
2017-03-13 15:24 ` Andy Lutomirski
2017-03-23 15:59 ` [PATCH] proc: allow to change proc mount options per mount Djalal Harouni
2017-03-20 12:58 ` [RFC] Add option to mount only a pids subset Alexey Gladkov
2017-03-23 16:05 ` Oleg Nesterov
2017-03-23 22:57 ` Alexey Gladkov
2017-03-23 16:06 ` Djalal Harouni
2017-03-23 22:07 ` Alexey Gladkov
2017-03-26 7:03 ` Djalal Harouni
2017-03-30 21:45 ` Alexey Gladkov
2017-02-27 18:56 ` [PATCH] Add pidfs filesystem Michael Kerrisk
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