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 <[email protected]>
> ---
> 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/