Re: Suggestion for better manpage.

[Ian Kent <raven@themaw.net>]

On Tue, 2008-06-17 at 12:57 +0200, Stef Bon wrote:
> Hello,
> 
> reading the manpage of automount, I would like to change the section in the 
> manpage about how the daemon reacts on signals.

Send a patch.

> 
> It is now:
> 
> 
> If  the  automount  daemon  catches  a  USR1  signal, it will umount all 
> currently unused autofs managed mounted file systems and continue running
>        (forced expire).  If it catches the TERM signal it will umount all 
> unused autofs managed mounted file systems and exit if there are  no  
> remaining
>        busy  file systems. If autofs has been compiled with the option to 
> ignore busy mounts on exit it will exit leaving any busy mounts in place 
> other-
>        wise busy file systems will not be umounted and autofs will not exit.  
> Alternatively, if autofs has been compiled with the option to enable forced
>        shutdown then a USR2 signal to the daemon will cause all mounts to be 
> umounted and any busy mounts to be forcibly umounted, including autofs mount
>        point directories (summary execution). Note that the forced umount is 
> an unlink operation and the actual umount will not happen in the kernel  un-
>        til active file handles are released.  The daemon also responds to a 
> HUP signal which triggers an update of the maps for each mount point.
> 
>        If any autofs mount point directories are busy when the daemon is sent 
> an exit signal the daemon will not exit. The exception to this is if autofs
>        has been built with configure options to either ignore busy mounts at 
> exit or force umount at exit. If the ignore busy mounts at  exit  option  is
>        used  the filesystems will be left in a catatonic (non-functional) 
> state and can be manually umounted when they become unused. If the force 
> umount
>        at exit option is used the filesystems will be umounted but the mount 
> will not be released by the kernel until they are no longer in  use  by  the
>        processes that held them busy.  If automount managed filesystems are 
> found mounted when autofs is started they will be recoverd unless they are no
>        longer present in the map in which case they need to umounted manually.
> 
> I would like to suggest:
> 
> The automount daemon can react on a few signals. Some of them are standard, 
> others are less standard and/or need compiletime options.
> 
> TERM
> 
> If it catches the TERM signal it will umount all unused autofs managed mounted 
> filesystems, and exit if there are no remaining mounts left. It will keep on 
> running (till??)

You eventually send a TERM signal and no mounts are in use.

> If compiled with the "ignore busy mounts" option, it will exit here, and leave 
> any mountpoint in place.
> 
> USR2
> This only applies when the automounter is compiled with the "enable forced 
> shudown". When it catches the USR2, it will umount all mounts, busy or not. 
> Note: umounting a busy mountpoint  is actually an unlink operation. The actual 
> umount will be done later, when all active file handleds are released. (this 
> id done by??)

Kernel.

> 
> USR1
> With the USR1 signal it will umount all currently unused mounts, and continue 
> running (forced expire).
> 
> HUP
> This signal triggers an update of the maps for each mountpoint.
> 
> 
>  I've left out some parts, but mostly rearranged the information. I've left 
> out the text "summary execution" Is it important?
> 
> But what do you think. Is it better this way?
> 
> Stef Bon
> 
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