[NFS-Ganesha-Devel] Re: Race between reusing MDCACHE entry of the parent and chunk_lru_run()

On 4/11/19, Frank Filz <ffilzlnx(a)mindspring.com&gt; wrote: >> From: Daniel Gryniewicz [mailto:dang@redhat.com] >> Sent: Thursday, April 11, 2019 5:28 AM >> >> Okay, I misunderstood the situation. That fix won't work, because >> mdcache_lru_unref_chunk() takes the qlane lock, and it also takes the >> content >> lock, which must be taken before the qlane lock. >> >> The problem here is that the parent has a pointer to the chunk and a ref >> on it, >> and the chunk has a pointer to the parent but no ref on it. >> This means that the parent refcount can go to zero while the chunk has a >> pointer. I think we need to force remove all the chunks when we recycle >> the >> parent, and null out the parent pointer in the chunk as well. We'll have >> to audit >> all the uses of the parent pointer and make sure the call path has a ref >> to the >> parent, or that it can handle a null parent pointer. Hi Daniel, By force cleaning, did you have something like this in mind? https://review.gerrithub.io/c/ffilz/nfs-ganesha/+/451311/1/src/FSAL/Stack...