From: "J. Bruce Fields" <bfields@fieldses.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Karel Zak <kzak@redhat.com>,
Lennart Poettering <mzxreary@0pointer.de>,
Miklos Szeredi <miklos@szeredi.hu>, Ian Kent <raven@themaw.net>,
David Howells <dhowells@redhat.com>,
Christian Brauner <christian.brauner@ubuntu.com>,
Al Viro <viro@zeniv.linux.org.uk>,
dray@redhat.com, Miklos Szeredi <mszeredi@redhat.com>,
Steven Whitehouse <swhiteho@redhat.com>,
Jeff Layton <jlayton@redhat.com>,
andres@anarazel.de, keyrings@vger.kernel.org,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Aleksa Sarai <cyphar@cyphar.com>
Subject: Re: Upcoming: Notifications, FS notifications and fsinfo()
Date: Mon, 06 Apr 2020 18:46:26 +0000 [thread overview]
Message-ID: <20200406184626.GE2147@fieldses.org> (raw)
In-Reply-To: <CAHk-=wjW735UE+byK1xsM9UvpF2ubh7bCMaAOwz575U7hRCKyA@mail.gmail.com>
On Mon, Apr 06, 2020 at 09:34:08AM -0700, Linus Torvalds wrote:
> On Mon, Apr 6, 2020 at 2:17 AM Karel Zak <kzak@redhat.com> wrote:
> >
> > On Fri, Apr 03, 2020 at 04:30:24PM -0400, J. Bruce Fields wrote:
> > >
> > > nfs-utils/support/misc/mountpoint.c:check_is_mountpoint() stats the file
> > > and ".." and returns true if they have different st_dev or the same
> > > st_ino. Comparing mount ids sounds better.
> >
> > BTW, this traditional st_dev+st_ino way is not reliable for bind mounts.
> > For mountpoint(1) we search the directory in /proc/self/mountinfo.
>
> These days you should probably use openat2() with RESOLVE_NO_XDEV.
>
> No need for any mountinfo or anything like that. Just look up the
> pathname and say "don't cross mount-points", and you'll get an error
> if it's a mount crossing lookup.
OK, I can't see why that wouldn't work, thanks.
--b.
>
> So this kind of thing is _not_ an argument for another kernel querying
> interface. We got a new (and better) model for a lot of this.
>
> Linus
WARNING: multiple messages have this Message-ID (diff)
From: "J. Bruce Fields" <bfields@fieldses.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Karel Zak <kzak@redhat.com>,
Lennart Poettering <mzxreary@0pointer.de>,
Miklos Szeredi <miklos@szeredi.hu>, Ian Kent <raven@themaw.net>,
David Howells <dhowells@redhat.com>,
Christian Brauner <christian.brauner@ubuntu.com>,
Al Viro <viro@zeniv.linux.org.uk>,
dray@redhat.com, Miklos Szeredi <mszeredi@redhat.com>,
Steven Whitehouse <swhiteho@redhat.com>,
Jeff Layton <jlayton@redhat.com>,
andres@anarazel.de, keyrings@vger.kernel.org,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Aleksa Sarai <cyphar@cyphar.com>
Subject: Re: Upcoming: Notifications, FS notifications and fsinfo()
Date: Mon, 6 Apr 2020 14:46:26 -0400 [thread overview]
Message-ID: <20200406184626.GE2147@fieldses.org> (raw)
In-Reply-To: <CAHk-=wjW735UE+byK1xsM9UvpF2ubh7bCMaAOwz575U7hRCKyA@mail.gmail.com>
On Mon, Apr 06, 2020 at 09:34:08AM -0700, Linus Torvalds wrote:
> On Mon, Apr 6, 2020 at 2:17 AM Karel Zak <kzak@redhat.com> wrote:
> >
> > On Fri, Apr 03, 2020 at 04:30:24PM -0400, J. Bruce Fields wrote:
> > >
> > > nfs-utils/support/misc/mountpoint.c:check_is_mountpoint() stats the file
> > > and ".." and returns true if they have different st_dev or the same
> > > st_ino. Comparing mount ids sounds better.
> >
> > BTW, this traditional st_dev+st_ino way is not reliable for bind mounts.
> > For mountpoint(1) we search the directory in /proc/self/mountinfo.
>
> These days you should probably use openat2() with RESOLVE_NO_XDEV.
>
> No need for any mountinfo or anything like that. Just look up the
> pathname and say "don't cross mount-points", and you'll get an error
> if it's a mount crossing lookup.
OK, I can't see why that wouldn't work, thanks.
--b.
>
> So this kind of thing is _not_ an argument for another kernel querying
> interface. We got a new (and better) model for a lot of this.
>
> Linus
next prev parent reply other threads:[~2020-04-06 18:46 UTC|newest]
Thread overview: 199+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 13:58 Upcoming: Notifications, FS notifications and fsinfo() David Howells
2020-03-30 13:58 ` David Howells
2020-03-30 14:31 ` [GIT PULL] General notification queue and key notifications David Howells
2020-03-30 14:31 ` David Howells
2020-03-31 6:51 ` Stephen Rothwell
2020-03-31 6:51 ` Stephen Rothwell
2020-06-02 15:55 ` David Howells
2020-06-02 15:55 ` David Howells
2020-06-03 2:15 ` Ian Kent
2020-06-03 2:15 ` Ian Kent
2020-06-08 0:49 ` Ian Kent
2020-06-08 0:49 ` Ian Kent
2020-06-10 9:56 ` Christian Brauner
2020-06-10 9:56 ` Christian Brauner
2020-06-10 11:12 ` Karel Zak
2020-06-10 11:12 ` Karel Zak
2020-06-12 21:32 ` Linus Torvalds
2020-06-12 21:32 ` Linus Torvalds
2020-06-13 13:04 ` David Howells
2020-06-13 13:04 ` David Howells
2020-06-13 16:47 ` Linus Torvalds
2020-06-13 16:47 ` Linus Torvalds
2020-06-13 17:03 ` Linus Torvalds
2020-06-13 17:03 ` Linus Torvalds
2020-06-13 19:22 ` Miklos Szeredi
2020-06-13 19:22 ` Miklos Szeredi
2020-06-12 22:01 ` Linus Torvalds
2020-06-12 22:01 ` Linus Torvalds
2020-06-13 13:24 ` David Howells
2020-06-13 13:24 ` David Howells
2020-06-13 18:00 ` pr-tracker-bot
2020-06-13 18:00 ` pr-tracker-bot
2020-06-17 1:15 ` Williams, Dan J
2020-06-17 1:15 ` Williams, Dan J
2020-06-17 1:15 ` Williams, Dan J
2020-06-23 23:38 ` Dan Williams
2020-06-23 23:38 ` Dan Williams
2020-06-23 23:38 ` Dan Williams
2020-06-24 0:55 ` David Howells
2020-06-24 0:55 ` David Howells
2020-06-24 0:55 ` David Howells
2020-06-24 1:03 ` Dan Williams
2020-06-24 1:03 ` Dan Williams
2020-06-24 1:03 ` Dan Williams
2020-06-24 1:17 ` David Howells
2020-06-24 1:17 ` David Howells
2020-06-24 1:17 ` David Howells
2020-03-30 14:36 ` [GIT PULL] Mount and superblock notifications David Howells
2020-03-30 14:36 ` David Howells
2020-04-04 21:13 ` Linus Torvalds
2020-04-04 21:13 ` Linus Torvalds
2020-04-05 22:52 ` Andres Freund
2020-04-05 22:52 ` Andres Freund
2020-03-30 14:43 ` [GIT PULL] fsinfo: Filesystem information query David Howells
2020-03-30 14:43 ` David Howells
2020-03-30 20:28 ` Upcoming: Notifications, FS notifications and fsinfo() Miklos Szeredi
2020-03-30 20:28 ` Miklos Szeredi
2020-03-31 9:21 ` Karel Zak
2020-03-31 9:21 ` Karel Zak
2020-03-31 17:31 ` David Howells
2020-03-31 17:31 ` David Howells
2020-03-31 19:42 ` Miklos Szeredi
2020-03-31 19:42 ` Miklos Szeredi
2020-03-31 19:47 ` David Howells
2020-03-31 19:47 ` David Howells
2020-03-31 21:14 ` David Howells
2020-03-31 21:14 ` David Howells
2020-03-31 21:23 ` David Howells
2020-03-31 21:23 ` David Howells
2020-03-30 21:17 ` Christian Brauner
2020-03-30 21:17 ` Christian Brauner
2020-03-31 5:11 ` Miklos Szeredi
2020-03-31 5:11 ` Miklos Szeredi
2020-03-31 8:15 ` Christian Brauner
2020-03-31 8:15 ` Christian Brauner
2020-03-31 8:34 ` Miklos Szeredi
2020-03-31 8:34 ` Miklos Szeredi
2020-03-31 8:34 ` Karel Zak
2020-03-31 8:34 ` Karel Zak
2020-03-31 8:56 ` Miklos Szeredi
2020-03-31 8:56 ` Miklos Szeredi
2020-03-31 9:49 ` Karel Zak
2020-03-31 9:49 ` Karel Zak
2020-03-31 12:25 ` Lennart Poettering
2020-03-31 12:25 ` Lennart Poettering
2020-03-31 15:10 ` Miklos Szeredi
2020-03-31 15:10 ` Miklos Szeredi
2020-03-31 15:24 ` Lennart Poettering
2020-03-31 15:24 ` Lennart Poettering
2020-03-31 21:56 ` David Howells
2020-03-31 21:56 ` David Howells
2020-03-31 21:54 ` David Howells
2020-03-31 21:54 ` David Howells
2020-04-01 8:43 ` Karel Zak
2020-04-01 8:43 ` Karel Zak
2020-03-31 7:22 ` Lennart Poettering
2020-03-31 7:22 ` Lennart Poettering
2020-03-31 21:52 ` David Howells
2020-03-31 21:52 ` David Howells
2020-04-01 9:04 ` Karel Zak
2020-04-01 9:04 ` Karel Zak
2020-04-01 13:34 ` Miklos Szeredi
2020-04-01 13:34 ` Miklos Szeredi
2020-04-01 13:55 ` David Howells
2020-04-01 13:55 ` David Howells
2020-04-01 13:58 ` David Howells
2020-04-01 13:58 ` David Howells
2020-04-01 15:25 ` Miklos Szeredi
2020-04-01 15:25 ` Miklos Szeredi
2020-04-01 16:01 ` David Howells
2020-04-01 16:01 ` David Howells
2020-04-01 16:30 ` Miklos Szeredi
2020-04-01 16:30 ` Miklos Szeredi
2020-04-02 15:22 ` David Howells
2020-04-02 15:22 ` David Howells
2020-04-02 15:24 ` David Howells
2020-04-02 15:24 ` David Howells
2020-04-02 15:24 ` Miklos Szeredi
2020-04-02 15:24 ` Miklos Szeredi
2020-04-02 15:42 ` David Howells
2020-04-02 15:42 ` David Howells
2020-04-03 9:11 ` Karel Zak
2020-04-03 9:11 ` Karel Zak
2020-04-01 14:41 ` Lennart Poettering
2020-04-01 14:41 ` Lennart Poettering
2020-04-01 15:33 ` Miklos Szeredi
2020-04-01 15:33 ` Miklos Szeredi
2020-04-01 16:06 ` David Howells
2020-04-01 16:06 ` David Howells
2020-04-01 16:40 ` Miklos Szeredi
2020-04-01 16:40 ` Miklos Szeredi
2020-04-02 2:52 ` Ian Kent
2020-04-02 2:52 ` Ian Kent
2020-04-02 13:52 ` Miklos Szeredi
2020-04-02 13:52 ` Miklos Szeredi
2020-04-02 14:36 ` Lennart Poettering
2020-04-02 14:36 ` Lennart Poettering
2020-04-02 15:22 ` Miklos Szeredi
2020-04-02 15:22 ` Miklos Szeredi
2020-04-02 15:28 ` Lennart Poettering
2020-04-02 15:28 ` Lennart Poettering
2020-04-02 15:35 ` Miklos Szeredi
2020-04-02 15:35 ` Miklos Szeredi
2020-04-02 15:50 ` Lennart Poettering
2020-04-02 15:50 ` Lennart Poettering
2020-04-02 17:20 ` Miklos Szeredi
2020-04-02 17:20 ` Miklos Szeredi
2020-04-03 11:08 ` Lennart Poettering
2020-04-03 11:08 ` Lennart Poettering
2020-04-03 11:48 ` Miklos Szeredi
2020-04-03 11:48 ` Miklos Szeredi
2020-04-03 15:01 ` Lennart Poettering
2020-04-03 15:01 ` Lennart Poettering
2020-04-06 9:22 ` Miklos Szeredi
2020-04-06 9:22 ` Miklos Szeredi
2020-04-06 17:29 ` Lennart Poettering
2020-04-06 17:29 ` Lennart Poettering
2020-04-07 2:21 ` Ian Kent
2020-04-07 2:21 ` Ian Kent
2020-04-07 13:59 ` Miklos Szeredi
2020-04-07 13:59 ` Miklos Szeredi
2020-04-07 15:53 ` Lennart Poettering
2020-04-07 15:53 ` Lennart Poettering
2020-04-07 16:06 ` Miklos Szeredi
2020-04-07 16:06 ` Miklos Szeredi
2020-04-02 15:51 ` David Howells
2020-04-02 15:51 ` David Howells
2020-04-02 15:56 ` David Howells
2020-04-02 15:56 ` David Howells
2020-04-03 1:44 ` Ian Kent
2020-04-03 1:44 ` Ian Kent
2020-04-03 11:11 ` Lennart Poettering
2020-04-03 11:11 ` Lennart Poettering
2020-04-03 11:38 ` Miklos Szeredi
2020-04-03 11:38 ` Miklos Szeredi
2020-04-03 12:05 ` Richard Weinberger
2020-04-03 12:05 ` Richard Weinberger
2020-04-03 15:12 ` Lennart Poettering
2020-04-03 15:12 ` Lennart Poettering
2020-04-03 15:36 ` David Howells
2020-04-03 15:36 ` David Howells
2020-04-03 15:41 ` Lennart Poettering
2020-04-03 15:41 ` Lennart Poettering
2020-04-03 20:30 ` J. Bruce Fields
2020-04-03 20:30 ` J. Bruce Fields
2020-04-06 8:35 ` Miklos Szeredi
2020-04-06 8:35 ` Miklos Szeredi
2020-04-06 16:07 ` J. Bruce Fields
2020-04-06 16:07 ` J. Bruce Fields
2020-04-06 9:17 ` Karel Zak
2020-04-06 9:17 ` Karel Zak
2020-04-06 16:34 ` Linus Torvalds
2020-04-06 16:34 ` Linus Torvalds
2020-04-06 18:46 ` J. Bruce Fields [this message]
2020-04-06 18:46 ` J. Bruce Fields
2020-04-06 18:48 ` Lennart Poettering
2020-04-06 18:48 ` Lennart Poettering
2020-04-08 3:36 ` Linus Torvalds
2020-04-08 3:36 ` Linus Torvalds
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