aliasing (or renaming) kern.geom.debugflags
Benjamin Kaduk
kaduk at MIT.EDU
Fri Oct 7 17:51:50 UTC 2011
On Fri, 7 Oct 2011, Garrett Cooper wrote:
> On Fri, Oct 7, 2011 at 10:42 AM, Benjamin Kaduk <kaduk at mit.edu> wrote:
>> Dear all,
>>
>> I feel like this has come up before, but a quick search didn't reveal
>> anything terribly recent, at least.
>>
>> The new installation chapter of the handbook for 9.0 (that Warren and Glen
>> and Garrett and Gavin and more people I am probably missing have sunk huge
>> amounts of time into) has instructions on (e.g.) preparing a USB stick
>> install image:
>> http://www.glenbarber.us/FreeBSD9/doc/en_US.ISO8859-1/books/handbook/install-pre.html
>> (scroll down most of the way). But in order to do so, the instructions
>> include 'sysctl kern.geom.debugflags=16'! Now, an ordinary user who is
>> doing this for the first time might ask, "why do I need to do something with
>> 'debugflags' in order to make a USB stick? I'm not debugging anything, this
>> is a standard operation!".
>>
>> I can't really advocate for changing the geom logic at this point in the
>> release cycle (though it's not really clear why rank 1 geom providers need
>> to be so special), but I think it would be nice to have a user-visible
>> interface to it that does not have "debug" in the name, since the actual
>> flags are apparently here for the long haul. I could certainly imagine
>> aliasing the debugflags to just "flags", which seems more
>> innocuous-sounding.
>>
>> Does this sound crazy?
>
> Yes. From geom(4):
>
> DIAGNOSTICS
> Several flags are provided for tracing GEOM operations and unlocking pro-
> tection mechanisms via the kern.geom.debugflags sysctl. All of these
> flags are off by default, and great care should be taken in turning them
> on.
>
> geom(4) has more details about what they do.
I'm not sure I follow your point. Yes, geom(4) describes what they do; my
objection is to the use of "debug" to describe the one in particular that
we tell new users to blindly set. A hypothetical kern.geom.flags need not
allow setting (e.g.) "0x01 (G_T_TOPOLOGY) Provide tracing of topology
change events" if we don't want it to.
-Ben
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