Re: [PATCH v2] Incremental: remove obsoleted calls to udisks

[Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>]

On Fri, 26 May 2023 22:42:52 +0800
Coly Li <colyli@suse.de> wrote:

> On Fri, May 26, 2023 at 09:52:00AM +0200, Mariusz Tkaczyk wrote:
> > On Fri, 26 May 2023 01:08:43 +0800
> > Coly Li <colyli@suse.de> wrote:
> >   
> > > Utilility udisks is removed from udev upstream, calling this obsoleted
> > > command in run_udisks() doesn't make any sense now.
> > > 
> > > This patch removes the calls chain of udisks, which includes routines
> > > run_udisk(), force_remove(), and 2 locations where force_remove() are
> > > called. Considering force_remove() is removed with udisks util, it is
> > > fair to remove Manage_stop() inside force_remove() as well.
> > > 
> > > After force_remove() is not called anymore, if Manage_subdevs() returns
> > > failure due to a busy array, nothing else to do. If the failure is from
> > > a broken array and verbose information is wanted, a warning message will
> > > be printed by pr_err().
> > > 
> > > Signed-off-by: Coly Li <colyli@suse.de>
> > > Cc: Mariusz Tkaczyk <mariusz.tkaczyk@intel.com>
> > > Cc: Jes Sorensen <jes@trained-monkey.org>
> > > ---
> > > Changelog,
> > > v2: improve based on code review comments from Mariusz.
> > > v1: initial version.
> > > 
> > >  Incremental.c | 88 ++++++++++++++++++++++++---------------------------
> > >  1 file changed, 42 insertions(+), 46 deletions(-)
> > > 
> > > diff --git a/Incremental.c b/Incremental.c
> > > index f13ce02..d390a08 100644
> > > --- a/Incremental.c
> > > +++ b/Incremental.c
> > > @@ -1628,56 +1628,38 @@ release:
> > >  	return rv;
> > >  }
> > >  
> > > -static void run_udisks(char *arg1, char *arg2)
> > > -{
> > > -	int pid = fork();
> > > -	int status;
> > > -	if (pid == 0) {
> > > -		manage_fork_fds(1);
> > > -		execl("/usr/bin/udisks", "udisks", arg1, arg2, NULL);
> > > -		execl("/bin/udisks", "udisks", arg1, arg2, NULL);
> > > -		exit(1);
> > > -	}
> > > -	while (pid > 0 && wait(&status) != pid)
> > > -		;
> > > -}
> > > -
> > > -static int force_remove(char *devnm, int fd, struct mdinfo *mdi, int
> > > verbose) -{
> > > -	int rv;
> > > -	int devid = devnm2devid(devnm);
> > > -
> > > -	run_udisks("--unmount", map_dev(major(devid), minor(devid), 0));
> > > -	rv = Manage_stop(devnm, fd, verbose, 1);
> > > -	if (rv) {
> > > -		/* At least we can try to trigger a 'remove' */
> > > -		sysfs_uevent(mdi, "remove");
> > > -		if (verbose)
> > > -			pr_err("Fail to stop %s too.\n", devnm);
> > > -	}
> > > -	return rv;
> > > -}
> > > -
> > >  static void remove_from_member_array(struct mdstat_ent *memb,
> > >  				    struct mddev_dev *devlist, int
> > > verbose) {
> > >  	int rv;
> > >  	struct mdinfo mmdi;
> > > +	char buf[32];  
> > 
> > Another place where we hard-coding array size. We already
> > addressed it (patch is waiting for internal regression), so please left it
> > as is for now. Just to let everyone know.
> >  
> 
> Yes, I agree. It should be good to do one thing in each patch. The hard-coding
> array size should be addressed in another patch series.
> 
>  
> > >  	int subfd = open_dev(memb->devnm);
> > >  
> > > -	if (subfd >= 0) {
> > > -		rv = Manage_subdevs(memb->devnm, subfd, devlist, verbose,
> > > -				    0, UOPT_UNDEFINED, 0);
> > > -		if (rv & 2) {
> > > -			if (sysfs_init(&mmdi, -1, memb->devnm))
> > > -				pr_err("unable to initialize sysfs for:
> > > %s\n",
> > > -				       memb->devnm);
> > > -			else
> > > -				force_remove(memb->devnm, subfd, &mmdi,
> > > -					     verbose);
> > > +	if (subfd < 0)
> > > +		return;
> > > +
> > > +	rv = Manage_subdevs(memb->devnm, subfd, devlist, verbose,
> > > +			    0, UOPT_UNDEFINED, 0);
> > > +	if (rv) {
> > > +		/*
> > > +		 * If the array is busy or no verbose info
> > > +		 * desired, nonthing else to do.
> > > +		 */
> > > +		if ((rv & 2) || verbose <= 0)
> > > +			goto close;
> > > +
> > > +		/* Otherwise if failed due to a broken array, warn */
> > > +		if (sysfs_init(&mmdi, -1, memb->devnm) == 0 &&
> > > +		    sysfs_get_str(&mmdi, NULL, "array_state",
> > > +				  buf, sizeof(buf)) > 0 &&
> > > +		    strncmp(buf, "broken", 6) == 0) {
> > > +			pr_err("Fail to remove %s from broken array.\n",
> > > +			       memb->devnm);  
> > 
> > The codes above and below are almost the same now, can we move them to a
> > function?  
> 
> There is a little difference on calling sysfs_init(), the second location
> doesn’t call sysfs_init(). It is possible to use a condition variable to
> handle the difference, but that will be another extra complication and
> not worthy IMHO.
> 

what about initializing the sysfs earlier and passing mdi to function? That
should resolve our problem.(Probably not a case anymore after dropping the
message).
> 
> > >  		}
> > > -		close(subfd);
> > >  	}
> > > +close:
> > > +	close(subfd);
> > >  }
> > >  
> > >  /*
> > > @@ -1760,11 +1742,22 @@ int IncrementalRemove(char *devname, char
> > > *id_path, int verbose) } else {
> > >  		rv |= Manage_subdevs(ent->devnm, mdfd, &devlist,
> > >  				    verbose, 0, UOPT_UNDEFINED, 0);
> > > -		if (rv & 2) {
> > > -		/* Failed due to EBUSY, try to stop the array.
> > > -		 * Give udisks a chance to unmount it first.
> > > -		 */
> > > -			rv = force_remove(ent->devnm, mdfd, &mdi,
> > > verbose);
> > > +		if (rv) {  
> > I would prefer to reverse logic to make one indentation less (if that is
> > possible):
> > if (rv != 0)
> >     goto end;
> > but it is fine anyway.  
> 
> Indeed I tends to remove all the warning messages, and do nothing else more
> if rv != 0 from Manage_subdevs(). How do you think of this idea? Checking the
> array state indeed doesn't help too much.

LGTM. Incremental remove is designed to be system utility so the warning are
less important. User should use MISC --faulty and --remove.
> 
> >   
> > > +			/*
> > > +			 * If the array is busy or no verbose info
> > > +			 * desired, nothing else to do.
> > > +			 */
> > > +			if ((rv & 2) || verbose <= 0)
> > > +				goto end;
> > > +
> > > +			/* Otherwise if failed due to a broken array,
> > > warn */
> > > +			if (sysfs_get_str(&mdi, NULL, "array_state",
> > > +					  buf, sizeof(buf)) > 0 &&
> > > +			    strncmp(buf, "broken", 6) == 0) {  
> > 
> > Broken is defined in sysfs_array_states[], can we use it?
> > if (map_name(sysfs_array_states, buf) == ARRAY_BROKEN)
> > I know that it could looks like a little overhead but compiler should do
> > the job here.  
> 
> Yes, I am aware of this. But the existed coding style in this file is the hard
> coded strncmp(). So if we do want to print the warning for a broken array, it
> would be better to add the map_name() fixing in another patch. I mean, do one
> thing in single patch.

Not a case if we are going to drop the message, correct? Feel free to handle
the state comparing across code in the future.
> 
> > > +				pr_err("Fail to remove %s from broken
> > > array.\n",
> > > +				       ent->devnm);  
> > Not exactly, The broken may be raised even if disk is removed. It is a case
> > for raid456 and raid1/10 with fail_last_dev=1. I would say just "%s is in
> > broken state.\n" 
> > Should be exclude arrays which are already broken (broken was set before we
> > called mdadm -If)? I don't see printing this message everytime as a
> > problem, but it is something you should consider.
> >  
> 
> Indeed, I still suggest to remove all the pr_err() stuffs, they cannot help
> too much, and introduce extra complication.

Ack.
> 
>  
> > And I forgot to say it eariler, could you consider adding test/s for both
> > IMSM and native? It is something that should be tested.
> > Sorry, scope is growing :(  
> 
> Sure, it's good idea, let's do it later.

Ok, thanks.

Mariusz