Re: [PATCH 12/16] GFS2: Mounting & sysfs interface

["Artem B. Bityutskiy" <dedekind@oktetlabs.ru>]

David Teigland wrote:
> On Tue, Apr 25, 2006 at 08:53:16PM +0400, Artem B. Bityutskiy wrote:
> 
>>Hello,
>>
>>last time I tried to use "bare" sysfs functions to create my sysfs 
>>hierarchy I ended up with a problem that the module refcount is not 
>>increased when those sysfs files are opened. So I could open a sysfs 
>>file from userspace, do rmmod and enjoy oops.
>>
>>Then I started using the class and class_device stuff, which have an 
>>.owner field, and all became fine.
>>
>>I'm not sure if this is a problem of sysfs, but I suspect it could take 
>>care of module refcount better.
>>
>>In your patch, I looked for THIS_MODULE pattern and did not find. I did 
>>not try, but I suspect your code is not devoid of the problem I 
>>described. So, this is just FYI and may be not the case.
> 
> 
> Others have also alluded to /sys/fs/ races that we'll probably need to
> resolve.  In this case the question is more about umount than rmmod since
> the mount should reference the module.
Right. I just thought you expose sysfs files even if you're not mounted. 
Sorry, I did not dig deeply.

-- 
Best regards, Artem B. Bityutskiy
Oktet Labs (St. Petersburg), Software Engineer.
+7 812 4286709 (office) +7 911 2449030 (mobile)
E-mail: dedekind@oktetlabs.ru, Web: www.oktetlabs.ru