[PATCH 06/14] sysfs: Rewrite sysfs_get_dentry
htejun at gmail.com
Wed Aug 1 10:51:19 PDT 2007
Eric W. Biederman wrote:
> Tejun Heo <htejun at gmail.com> writes:
>> Hmmm... I think we can live with a bit of complexity in
>> sysfs_get_dentry(). It's very well localized and not even long. I have
>> been trying hard to untangle sysfs internals from vfs and have a bit of
>> resistance against going back. But, then again, if we can achieve
>> something better and simpler, why not?
> Right now my real challenge is untangling sysfs_move_dir. In the
> case of multiple mounts of the sysfs tree.
OIC. Yeah, I guess moving a sd with multiple dentries attached could be
> My practical problem is that I need to hold a lock for the sysfs
> dirents and while that lock is held I need to call sysfs_get_dentry
> for the destination directory once for each superblock.
> It might be that some kind of reader-writer lock strategy is what
> I need to untangle this mess. Rather then making changing to i_mutex.
> All I know is at the moment it is taking a lot of code reading and
> brain storm to come of with something that is easy to maintain.
Just in case, sysfs used to have sysfs_rename_rwsem to protect
move/rename against tree walking, which became unnecessary after i_mutex
-> sysfs_mutex conversion. Move/rename can use stupid big fat locks if
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