From: Karel Zak <kzak@redhat.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: 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>,
Linus Torvalds <torvalds@linux-foundation.org>,
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@vger.kernel.org, linux-kernel@vger.kernel.org,
Aleksa Sarai <cyphar@cyphar.com>
Subject: Re: Upcoming: Notifications, FS notifications and fsinfo()
Date: Mon, 06 Apr 2020 09:17:01 +0000 [thread overview]
Message-ID: <20200406091701.q7ctdek2grzryiu3@ws.net.home> (raw)
In-Reply-To: <20200403203024.GB27105@fieldses.org>
On Fri, Apr 03, 2020 at 04:30:24PM -0400, J. Bruce Fields wrote:
> On Fri, Apr 03, 2020 at 05:12:23PM +0200, Lennart Poettering wrote:
> > BTW, while we are at it: one more thing I'd love to see exposed by
> > statx() is a simple flag whether the inode is a mount point. There's
> > plenty code that implements a test like this all over the place, and
> > it usually isn't very safe. There's one implementation in util-linux
> > for example (in the /usr/bin/mountpoint binary), and another one in
> > systemd. Would be awesome to just have a statx() return flag for that,
> > that would make things *so* much easier and more robust. because in
> > fact most code isn't very good that implements this, as much of it
> > just compares st_dev of the specified file and its parent. Better code
> > compares the mount ID, but as mentioned that's not as pretty as it
> > could be so far...
>
> 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.
> So anyway, yes, everybody reinvents the wheel here, and this would be
> useful.
+1
Karel
--
Karel Zak <kzak@redhat.com>
http://karelzak.blogspot.com
next prev parent reply other threads:[~2020-04-06 9:17 UTC|newest]
Thread overview: 97+ 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 14:31 ` [GIT PULL] General notification queue and key notifications David Howells
2020-03-31 6:51 ` Stephen Rothwell
2020-06-02 15:55 ` David Howells
2020-06-03 2:15 ` Ian Kent
2020-06-08 0:49 ` Ian Kent
2020-06-10 9:56 ` Christian Brauner
2020-06-10 11:12 ` Karel Zak
2020-06-12 21:32 ` Linus Torvalds
2020-06-12 22:01 ` Linus Torvalds
2020-06-13 13:04 ` David Howells
2020-06-13 16:47 ` Linus Torvalds
2020-06-13 17:03 ` Linus Torvalds
2020-06-13 19:22 ` Miklos Szeredi
2020-06-13 13:24 ` David Howells
2020-06-13 18:00 ` pr-tracker-bot
2020-06-17 1:15 ` Williams, Dan J
2020-06-23 23:38 ` Dan Williams
2020-06-24 0:55 ` David Howells
2020-06-24 1:03 ` Dan Williams
2020-06-24 1:17 ` David Howells
2020-03-30 14:36 ` [GIT PULL] Mount and superblock notifications David Howells
2020-04-04 21:13 ` Linus Torvalds
2020-04-05 22:52 ` Andres Freund
2020-03-30 14:43 ` [GIT PULL] fsinfo: Filesystem information query David Howells
2020-03-30 20:28 ` Upcoming: Notifications, FS notifications and fsinfo() Miklos Szeredi
2020-03-31 9:21 ` Karel Zak
2020-03-30 21:17 ` Christian Brauner
2020-03-31 5:11 ` Miklos Szeredi
2020-03-31 8:15 ` Christian Brauner
2020-03-31 8:34 ` Miklos Szeredi
2020-03-31 8:34 ` Karel Zak
2020-03-31 8:56 ` Miklos Szeredi
2020-03-31 9:49 ` Karel Zak
2020-03-31 12:25 ` Lennart Poettering
2020-03-31 15:10 ` Miklos Szeredi
2020-03-31 15:24 ` Lennart Poettering
2020-03-31 21:56 ` David Howells
2020-03-31 21:54 ` David Howells
2020-04-01 8:43 ` Karel Zak
2020-03-31 7:22 ` Lennart Poettering
2020-03-31 17:31 ` David Howells
2020-03-31 19:42 ` Miklos Szeredi
2020-03-31 19:47 ` David Howells
2020-03-31 21:14 ` David Howells
2020-03-31 21:23 ` David Howells
2020-03-31 21:52 ` David Howells
2020-04-01 9:04 ` Karel Zak
2020-04-01 13:34 ` Miklos Szeredi
2020-04-01 13:55 ` David Howells
2020-04-01 13:58 ` David Howells
2020-04-01 15:25 ` Miklos Szeredi
2020-04-03 9:11 ` Karel Zak
2020-04-01 16:01 ` David Howells
2020-04-01 16:30 ` Miklos Szeredi
2020-04-02 15:22 ` David Howells
2020-04-02 15:24 ` Miklos Szeredi
2020-04-02 15:42 ` David Howells
2020-04-02 15:24 ` David Howells
2020-04-01 14:41 ` Lennart Poettering
2020-04-01 15:33 ` Miklos Szeredi
2020-04-01 16:06 ` David Howells
2020-04-01 16:40 ` Miklos Szeredi
2020-04-02 2:52 ` Ian Kent
2020-04-02 13:52 ` Miklos Szeredi
2020-04-02 14:36 ` Lennart Poettering
2020-04-02 15:22 ` Miklos Szeredi
2020-04-02 15:28 ` Lennart Poettering
2020-04-02 15:35 ` Miklos Szeredi
2020-04-02 15:50 ` Lennart Poettering
2020-04-02 17:20 ` Miklos Szeredi
2020-04-03 11:08 ` Lennart Poettering
2020-04-03 11:48 ` Miklos Szeredi
2020-04-03 15:01 ` Lennart Poettering
2020-04-06 9:22 ` Miklos Szeredi
2020-04-06 17:29 ` Lennart Poettering
2020-04-07 2:21 ` Ian Kent
2020-04-07 13:59 ` Miklos Szeredi
2020-04-07 15:53 ` Lennart Poettering
2020-04-07 16:06 ` Miklos Szeredi
2020-04-02 15:51 ` David Howells
2020-04-02 15:56 ` David Howells
2020-04-03 1:44 ` Ian Kent
2020-04-03 11:11 ` Lennart Poettering
2020-04-03 11:38 ` Miklos Szeredi
2020-04-03 12:05 ` Richard Weinberger
2020-04-03 15:12 ` Lennart Poettering
2020-04-03 20:30 ` J. Bruce Fields
2020-04-06 8:35 ` Miklos Szeredi
2020-04-06 16:07 ` J. Bruce Fields
2020-04-06 9:17 ` Karel Zak [this message]
2020-04-06 16:34 ` Linus Torvalds
2020-04-06 18:46 ` J. Bruce Fields
2020-04-06 18:48 ` Lennart Poettering
2020-04-08 3:36 ` Linus Torvalds
2020-04-03 15:36 ` David Howells
2020-04-03 15:41 ` Lennart Poettering
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