Messages in this thread | | | Date | Fri, 30 Aug 2013 17:10:45 -0400 | From | Waiman Long <> | Subject | Re: [PATCH v7 1/4] spinlock: A new lockref structure for lockless update of refcount |
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On 08/30/2013 04:54 PM, Al Viro wrote: > On Fri, Aug 30, 2013 at 01:43:11PM -0700, Linus Torvalds wrote: >> On Fri, Aug 30, 2013 at 1:15 PM, Waiman Long<waiman.long@hp.com> wrote: >>> The prepend_path() isn't all due to getcwd. The correct profile should be >> Ugh. I really think that prepend_path() should just be rewritten to >> run entirely under RCU. >> >> Then we can remove *all* the stupid locking, and replace it with doing >> a read-lock on the rename sequence count, and repeating if requited. >> >> That shouldn't even be hard to do, it just requires mindless massaging >> and being careful. > Not really. Sure, you'll retry it if you race with d_move(); that's not > the real problem - access past the end of the object containing ->d_name.name > would screw you and that's what ->d_lock is preventing there. Delayed freeing > of what ->d_name is pointing into is fine, but it's not the only way to get > hurt there...
Actually, prepend_path() was called with rename_lock taken. So d_move() couldn't be run at the same time. Am I right?
Regards, Longman
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