[dm-devel] [PATCH 0/4] Add "reconfigure all" multipath command

[Benjamin Marzinski]

On Fri, Sep 24, 2021 at 10:44:46PM +0200, Xose Vazquez Perez wrote:
> On 9/21/21 01:21, Benjamin Marzinski wrote:
> 
> >This patchset is supposed to replace Martin's
> >
> >multipathd: add "force_reconfigure" option
> >
> >patch from his uxlsnr overhaul patchset. It also makes the default
> >reconfigure be a weak reconfigure, but instead of adding a configuration
> >option to control this, it adds a new multipathd command,
> >"reconfigure all", to do a full reconfigure. The HUP signal is left
> >doing only weak reconfigures.
> >In order to keep from having two states that are handled nearly
> >identically, the code adds an extra variable to track the type of
> >configuration that was selected, but this could easily be switch to
> >use a new DAEMON_CONFIGURE_ALL state instead.
> >The final patch, that added the new command, is meant to apply on top of
> >Martin's changed client handler code. I can send one that works with the
> >current client handler code, if people would rather review that.
> 
> This change is going to affect some places, raw search:

Yes. I specifically broke the code that actually changes how multipathd
operates from a user' point of view into a seperate patch (4/4) because
distributions might need to revert in, if they want to pull in recent
upstream changes, but don't what this kind of change in multipathd's
behavior.

I admit, this patchset needs to include documentation to mention the
changed behavior. I'll add that.  But I'm not sure what to make of the
list below.  I don't see any code in it that I didn't think about.  We
can disagree as to whether, for instance, dmmp_reconfig() should do a
full or a weak reconfig. But without some more information, I'm not sure
what you are asking of me.

-Ben

> $ git grep reconfigure
> libdmmp/libdmmp.c:      snprintf(cmd, _IPC_MAX_CMD_LEN, "%s", "reconfigure");
> libmultipath/configure.c:        * If we are in this code path (startup or forced reconfigure),
> libmultipath/foreign.h:  * don't support it. "multipathd reconfigure" starts foreign device
> libmultipath/foreign.h:  * This is called if multipathd reconfigures itself.
> multipath/main.c:               p += snprintf(p, n, "reconfigure");
> multipathd/cli.c:       r += add_key(keys, "reconfigure", RECONFIGURE, 0);
> multipathd/cli_handlers.c:cli_reconfigure(void * v, char ** reply, int * len, void * data)
> multipathd/cli_handlers.c:      condlog(2, "reconfigure (operator)");
> multipathd/cli_handlers.h:int cli_reconfigure(void * v, char ** reply, int * len, void * data);
> multipathd/main.c:                              condlog(2, "reconfigure (delayed)");
> multipathd/main.c:      set_unlocked_handler_callback(RECONFIGURE, cli_reconfigure);
> multipathd/main.c:              condlog(2, "reconfigure (delayed)");
> multipathd/main.c:reconfigure (struct vectors * vecs)
> multipathd/main.c:              condlog(2, "reconfigure (signal)");
> multipathd/main.c:                              reconfigure(vecs);
> multipathd/main.h:int reconfigure (struct vectors *);
> multipathd/multipathd.8:happens, it will reconfigure the multipath map the path belongs to, so that this
> multipathd/multipathd.8:.B reconfigure
> multipathd/multipathd.service:ExecReload=/sbin/multipathd reconfigure
> multipathd/uxlsnr.c:     * do it once per reconfigure */