Re: [Ocfs2-devel] [RFC][PATCH 0/3] configfs: Make nested defaultgroups lockdep-friendly

[Joel Becker]

On Tue, May 20, 2008 at 06:33:20PM +0200, Louis Rilling wrote:
> The following patches fix lockdep warnings resulting from (correct) recursive
> locking in configfs.
> 
> Current lockdep annotations for inode mutexes in configfs are lockdep-friendly
> provided that:
> 1/ config_groups have at most one level of default groups (see
>    configfs_attach_group()),
> 2/ config_groups having default groups are never removed (see
>    configfs_detach_prep()).
> 
> Since lockdep does not handle such correct recursion, the idea is to insert
> lockdep_off()/lockdep_on() for inode mutexes as soon as the level of recursion
> of the I_MUTEX_PARENT -> I_MUTEX_CHILD dependency pattern increases.

	Hmm, this is definitely a more readable solution than the
previous, but I'm also with Arjan that it's scary :-)

Joel

-- 

"Ninety feet between bases is perhaps as close as man has ever come
 to perfection."
	- Red Smith

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@xxxxxxxxxx
Phone: (650) 506-8127
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