From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: Re: [PATCH] umount.2: Correct the description of MNT_DETACH Date: Mon, 02 Feb 2015 16:34:34 +0100 Message-ID: <54CF990A.8010807@gmail.com> References: <87lhp12a2i.fsf@x220.int.ebiederm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: mtk.manpages@gmail.com, Andy Lutomirski , Andrey Wagin , linux-fsdevel@vger.kernel.org, Al Viro , linux-kernel@vger.kernel.org To: "Eric W. Biederman" Return-path: In-Reply-To: <87lhp12a2i.fsf@x220.int.ebiederm.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 09/30/2014 03:04 AM, Eric W. Biederman wrote: > > I recently realized that I had been reasoning improperly about what > umount(MNT_DETACH) did based on an insufficient description in > the umount.2 man page, that matched my intuition but not the > implementation. > > When there are no submounts MNT_DETACH is essentially harmless to > applications. Where there are submounts MNT_DETACH changes what > is visible to applications using the detach directories. Thanks, Eric, and sorry for the delay. I've applied this now. Cheers, Michael > Signed-off-by: Eric W. Biederman > --- > man2/umount.2 | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/man2/umount.2 b/man2/umount.2 > index 5ff88152c738..aea39d8306fe 100644 > --- a/man2/umount.2 > +++ b/man2/umount.2 > @@ -66,9 +66,10 @@ This can cause data loss. > (Only for NFS mounts.) > .TP > .BR MNT_DETACH " (since Linux 2.4.11)" > -Perform a lazy unmount: make the mount point unavailable for > -new accesses, and actually perform the unmount when the mount point > -ceases to be busy. > +Perform a lazy unmount: make the mount point unavailable for new > +accesses, immediately disconnect the filesystem and all filesystems > +mounted below it from each other and from the mount table, and > +actually perform the unmount when the mount point ceases to be busy. > .TP > .BR MNT_EXPIRE " (since Linux 2.6.8)" > Mark the mount point as expired. > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/