Re: [PATCH] mkfs.ubifs: remove the check for UBIFS_MAX_LEB_SZ

[Artem Bityutskiy <dedekind1@gmail.com>]

On Mon, 2015-08-24 at 14:37 +0800, Dongsheng Yang wrote:
> On 08/24/2015 02:32 PM, Artem Bityutskiy wrote:
> > On Mon, 2015-08-24 at 09:07 +0800, Dongsheng Yang wrote:
> > > On 08/18/2015 04:52 PM, Artem Bityutskiy wrote:
> > > > On Tue, 2015-08-18 at 12:52 +0800, Dongsheng Yang wrote:
> > > > > There is a commit 92ed6c0 to increase UBIFS_MAX_LEB_SZ
> > > > > to 2MiB. But recently, as the leb size become larger and
> > > > > larger, 2MiB is not a suitable limit any more.
> > > > > 
> > > > > Then remove this check in mkfs.ubifs
> > > > > 
> > > > > Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
> > > > > ---
> > > > > NOTE:
> > > > > 	I am not sure the reason why we have to
> > > > > limit the leb size in mkfs.ubifs. Because
> > > > > I did not find any reason for it, I send
> > > > > this patch out. It's very possible I am
> > > > > mising something.
> > > > 
> > > > Well, this is sanity check for the user input. If you
> > > > accidentally
> > > > added few zeroes, we want to spot this and inform you, and you
> > > > may
> > > > appreciate that we did not just created a bugus image for you.
> > > > That's
> > > > the idea.
> > > 
> > > Sorry, Artem, I was trying to understand it, but I did not got
> > > the
> > > point. Could you give me some more information about the idea?
> > > Maybe
> > > an example?
> > 
> > Well, this is defensive programming concept.
> 
> Ha, okey, got it. That's good.
> 
> But I got a device with ped_size=32M. (Although that would affect
> ubi/ubifs performance negatively, that's another topic) I am
> not sure increasing the MAX_LEB_SIZE to 32M is a good idea, at least
> I don't think it's convincing to others that "I have a device with
> 32M
> peb, so I will increase it to 32M". Could you give me some more
> suggestion?

Well, defensive programming is just a generally useful concept, it
helps to reveal problems, rather than help them hide.

But sometimes it stands on your way, in which case you need to relax
the defense. I already suggested to change the constant to the size you
need. I'd appreciate also a comment telling about the system which
needs 32MiB, if possible.

Artem.