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From: Jann Horn <jannh@google.com>
To: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	raven@themaw.net, Miklos Szeredi <mszeredi@redhat.com>,
	Christian Brauner <christian@brauner.io>,
	Linux API <linux-api@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 13/19] vfs: Add a mount-notification facility [ver #16]
Date: Wed, 19 Feb 2020 23:55:26 +0100	[thread overview]
Message-ID: <CAG48ez3gtZPn9hC565J4L0yyjW521T8Pg7FX+7R1B3mAcmXfyA@mail.gmail.com> (raw)
In-Reply-To: <CAG48ez3ZMg4O5US3n=p1CYK-2AAgLRY+pjnUXp2p5hdwbjCRSA@mail.gmail.com>

On Wed, Feb 19, 2020 at 11:40 PM Jann Horn <jannh@google.com> wrote:
> On Tue, Feb 18, 2020 at 6:07 PM David Howells <dhowells@redhat.com> wrote:
[...]
> > +                       watch = NULL;
> > +               }
> > +               up_write(&m->mnt.mnt_sb->s_umount);
> > +       } else {
> > +               ret = -EBADSLT;
> > +               if (m->mnt_watchers) {
> > +                       down_write(&m->mnt.mnt_sb->s_umount);
> > +                       ret = remove_watch_from_object(m->mnt_watchers, wqueue,
> > +                                                      (unsigned long)path.dentry,
> > +                                                      false);
>
> What exactly is the implication of only using the dentry as key here
> (and not the mount)? Does this mean that if you watch install watches
> on two bind mounts of the same underlying filesystem, the notification
> mechanism gets confused?

Ah, nevermind, I understand this one now... this operation only
removes watches on this mount with that dentry, and so together, that
means it effectively removes watches by the full path.

  reply	other threads:[~2020-02-19 22:55 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-18 17:04 [PATCH 00/19] VFS: Filesystem information and notifications [ver #16] David Howells
2020-02-18 17:05 ` [PATCH 01/19] vfs: syscall: Add fsinfo() to query filesystem information " David Howells
2020-02-19 16:31   ` Darrick J. Wong
2020-02-19 20:07   ` Jann Horn
2020-02-20 10:34   ` David Howells
2020-02-20 15:48     ` Darrick J. Wong
2020-02-20 11:03   ` David Howells
2020-02-20 14:54     ` Jann Horn
2020-02-20 15:31       ` Darrick J. Wong
2020-02-18 17:05 ` [PATCH 02/19] fsinfo: Add syscalls to other arches " David Howells
2020-02-21 14:51   ` Christian Brauner
2020-02-21 18:10     ` Geert Uytterhoeven
2020-02-18 17:05 ` [PATCH 03/19] fsinfo: Provide a bitmap of supported features " David Howells
2020-02-19 16:37   ` Darrick J. Wong
2020-02-20 12:22   ` David Howells
2020-02-18 17:05 ` [PATCH 04/19] vfs: Add mount change counter " David Howells
2020-02-21 14:48   ` Christian Brauner
2020-02-18 17:05 ` [PATCH 05/19] vfs: Introduce a non-repeating system-unique superblock ID " David Howells
2020-02-19 16:53   ` Darrick J. Wong
2020-02-20 12:45   ` David Howells
2020-02-18 17:05 ` [PATCH 06/19] vfs: Allow fsinfo() to look up a mount object by " David Howells
2020-02-21 15:09   ` Christian Brauner
2020-02-18 17:05 ` [PATCH 07/19] vfs: Allow mount information to be queried by fsinfo() " David Howells
2020-02-18 17:05 ` [PATCH 08/19] vfs: fsinfo sample: Mount listing program " David Howells
2020-02-18 17:06 ` [PATCH 09/19] fsinfo: Allow the mount topology propogation flags to be retrieved " David Howells
2020-02-18 17:06 ` [PATCH 10/19] fsinfo: Add API documentation " David Howells
2020-02-18 17:06 ` [PATCH 11/19] afs: Support fsinfo() " David Howells
2020-02-19 21:01   ` Jann Horn
2020-02-20 12:58   ` David Howells
2020-02-20 14:58     ` Jann Horn
2020-02-21 13:26     ` David Howells
2020-02-18 17:06 ` [PATCH 12/19] security: Add hooks to rule on setting a superblock or mount watch " David Howells
2020-02-18 17:06 ` [PATCH 13/19] vfs: Add a mount-notification facility " David Howells
2020-02-19 22:40   ` Jann Horn
2020-02-19 22:55     ` Jann Horn [this message]
2020-02-21 12:24   ` David Howells
2020-02-21 15:49     ` Jann Horn
2020-02-21 17:06     ` David Howells
2020-02-21 17:36       ` seq_lock and lockdep_is_held() assertions Jann Horn
2020-02-21 18:02         ` John Stultz
2020-02-18 17:06 ` [PATCH 14/19] notifications: sample: Display mount tree change notifications [ver #16] David Howells
2020-02-18 17:06 ` [PATCH 15/19] vfs: Add superblock " David Howells
2020-02-19 23:08   ` Jann Horn
2020-02-21 14:23   ` David Howells
2020-02-21 15:44     ` Jann Horn
2020-02-21 16:33     ` David Howells
2020-02-21 16:41       ` Jann Horn
2020-02-21 17:11       ` David Howells
2020-02-18 17:06 ` [PATCH 16/19] fsinfo: Provide superblock notification counter " David Howells
2020-02-18 17:07 ` [PATCH 17/19] notifications: sample: Display superblock notifications " David Howells
2020-02-18 17:07 ` [PATCH 18/19] ext4: Add example fsinfo information " David Howells
2020-02-19 17:04   ` Darrick J. Wong
2020-02-20  0:53   ` kbuild test robot
2020-02-21 14:43   ` David Howells
2020-02-21 16:26     ` Darrick J. Wong
2020-02-18 17:07 ` [PATCH 19/19] nfs: Add example filesystem " David Howells
2020-02-20  2:13   ` kbuild test robot
2020-02-20  2:20   ` kbuild test robot
2020-02-18 18:12 ` David Howells
2020-02-19 10:23 ` [PATCH 00/19] VFS: Filesystem information and notifications " Stefan Metzmacher
2020-02-19 14:46 ` Christian Brauner
2020-02-19 15:50   ` Darrick J. Wong
2020-02-20  4:42   ` Ian Kent
2020-02-20  9:09     ` Christian Brauner
2020-02-20 11:30       ` Ian Kent
2020-02-19 16:16 ` David Howells
2020-02-21 12:57 ` David Howells

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