Message-ID: <54CF990A.8010807@gmail.com>
Date: Mon, 02 Feb 2015 16:34:34 +0100
From: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
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To: "Eric W. Biederman" <ebiederm@xmission.com>
CC: mtk.manpages@gmail.com, Andy Lutomirski <luto@amacapital.net>,
        Andrey Wagin <avagin@gmail.com>, linux-fsdevel@vger.kernel.org,
        Al Viro <viro@ZenIV.linux.org.uk>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] umount.2: Correct the description of MNT_DETACH
References: <87lhp12a2i.fsf@x220.int.ebiederm.org>
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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 <ebiederm@xmission.com>
> ---
>  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/
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