From: Dave Chinner <david@fromorbit.com>
To: Lennart Poettering <mzxreary@0pointer.de>
Cc: Richard Weinberger <richard@nod.at>,
gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
"systemd-devel@lists.freedesktop.org"
<systemd-devel@lists.freedesktop.org>
Subject: Re: [PATCH] x86: defconfig: Enable CONFIG_FHANDLE
Date: Mon, 1 Dec 2014 14:54:26 +1100 [thread overview]
Message-ID: <20141201035426.GK9561@dastard> (raw)
In-Reply-To: <20141201010343.GB18495@gardel-login>
On Mon, Dec 01, 2014 at 02:03:43AM +0100, Lennart Poettering wrote:
> On Mon, 01.12.14 01:41, Richard Weinberger (richard@nod.at) wrote:
>
> > CC'ing systemd folks.
> >
> > Lennart, can you please explain why you need CONFIG_FHANDLE for systemd?
> > Maybe I'm reading the source horrible wrong.
>
> For two usecases:
>
> a) Being able to detect if something is a mount point. The traditional
> way to do this is by stat()ing the dir in question and its parent
> and comparing st_dev. That logic is not able to detect bind mounts
> however, if destination and the place the mount is at are actually
> on the same file system... Thus we check the mount id too, if we
> can get our hands on it.
So what you really want in the mount id in st_buf.st_dev, not the
underlying device number. i.e. fstatat(dirfd, path, buf,
AT_MOUNTID)?
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2014-12-01 3:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-25 23:36 [PATCH] x86: defconfig: Enable CONFIG_FHANDLE Richard Weinberger
2014-11-25 23:43 ` Dave Jones
2014-11-26 0:11 ` Richard Weinberger
2014-11-26 9:43 ` Paul Bolle
2014-11-25 23:51 ` Greg KH
2014-11-26 0:11 ` Richard Weinberger
2014-11-26 0:55 ` Greg KH
2014-11-26 8:13 ` Richard Weinberger
2014-11-26 9:30 ` Paul Bolle
2014-11-30 20:54 ` Dave Chinner
2014-11-30 21:08 ` Richard Weinberger
2014-12-01 0:18 ` Dave Chinner
2014-12-01 0:41 ` Richard Weinberger
2014-12-01 1:03 ` Lennart Poettering
2014-12-01 3:54 ` Dave Chinner [this message]
2014-12-01 12:42 ` Lennart Poettering
2014-12-09 10:18 ` [tip:x86/debug] x86/kconfig/defconfig: Enable CONFIG_FHANDLE=y tip-bot for Richard Weinberger
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