[ltt-dev] [PATCH 1/2] Make lttctl mount debugfs automatically

[zhaolei@cn.fujitsu.com (Zhaolei)]

* From: "Mathieu Desnoyers" <compudj@krystal.dyndns.org>
>* Zhaolei (zhaolei at cn.fujitsu.com) wrote:
>> * From: "Pierre-Marc Fournier" <pierre-marc.fournier@polymtl.ca>
>> > Zhaolei wrote:
>> >> lttctl need debugfs mounted,
>> >> This patch make lttctl mount debugfs automatically when it is not mounted.
>> >> 
>> > 
>> > Isn't having a utility such as lttctl mount filesystems against standard
>> > unix semantics? Can you give an example of another standard command that
>> > uses a filesystem and that tries to mount it if it isn't already
>> > mounted? 
>> Hello, Pierre-Marc,
>> 
>> I can give a an example.
>> It is SystemTap.
>> 
> 
> No offence, but can you find an example which is not explicitly
> described as "bad taste" example by many people in the Linux kernel
> community ?
Hello, Mathieu

I can't find another example of mounting debugfs automatically.
Maybe it is because debugfs is not widely used as others such as sysfs and
procfs.

sysfs and procfs are mounted in boot, and user-mode tools need not check and
mount then again. But debugfs is not too useful for normal user who just use
linux to edit text and browse internet, so mount debugfs in boot period is not
a good idea.
So, IMHO, debugfs's usage is not same as sysfs and procfs, we need not mount
sysfs and procfs in user-mode program, but maybe it is different for debugfs.

On the other hand, I also understand your opinion, mount a fs in program looks
strange(but can make user easy to use...), so you can feel free to ignore this
patch.
Same with [PATCH 2/2] Make lttctl load ltt-trace-control module automatically.

Regards
Zhaolei

> 
> Mathieu
> 
>> Regards
>> Zhaolei
>> 
>> > My guess is we should warn about the filesystem not being
>> > mounted, but not try to call mount() directly.
>> > 
>> >> Little cleanup also done(combile 2 getdebugfsmntdir() into one).
>> >> 
>> >> Applies on top of ltt-control-0.63-03012009.
>> >> 
>> > 
>> >
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>> 
> 
> -- 
> Mathieu Desnoyers
> OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
> 
>