[dm-devel] [PATCH 01/14] multipathd: return if dm_get_major_minor failed in, cli_add_map

[Martin Wilck]

On Fri, 2020-09-04 at 10:48 +0800, lixiaokeng wrote:
> 
> On 2020/9/4 1:26, Martin Wilck wrote:
> > Why not just quit the "do" loop in the error case
> > for dm_get_major_minor()?
> > 
> > Martin
> 
> If dm_get_major failed at first time, it will be executed again
> for some reason I don't know in the original code. Quiting the
> "do" loop in the error case for dm_get_major_minor() is against
> the twice attempt rule.

Right. 

Then, to solve the problem you're concerned about, it should be
sufficient to initialize both major and minor to -1, or simply refrain
from printing them in the log message in the first place.

At a closer look, the logic of the function is flawed; at least
if get_refwwid() doesn't return a usable refwwid, there's no point in
trying again.

Thanks,
Martin


> 
> Lixiaokeng
> > >  		else {
> > >  			sprintf(dev_path, "dm-%d", minor);
> > >  			alias = dm_mapname(major, minor);
> > > +			if (!alias)
> > > +				condlog(2, "%s: mapname not found for
> > > %d:%d",
> > > +					param, major, minor);
> > >  		}
> > >  		/*if there is no mapname found, we first create the
> > > device*/
> > >  		if (!alias && !count) {
> > > -			condlog(2, "%s: mapname not found for %d:%d",
> > > -				param, major, minor);
> > >  			get_refwwid(CMD_NONE, param, DEV_DEVMAP,
> > >  				    vecs->pathvec, &refwwid);
> > >  			if (refwwid) {
> > 
> > 
> > .
> >