Description of problem:
With https://review.gluster.org/#/c/glusterfs/+/21783/, we have made changes to offload processing upcall notifications to synctask so as not to block epoll threads. However seems like the purpose wasnt fully resolved.
In "glfs_cbk_upcall_data" -> "synctask_new1" after creating synctask if there is no callback defined, the thread waits on synctask_join till the syncfn is finished. So that way even with those changes, epoll threads are blocked till the upcalls are processed.
Hence the right fix now is to define a callback function for that synctask "glfs_cbk_upcall_syncop" so as to unblock epoll/notify threads completely and the upcall processing can happen in parallel by synctask threads.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
Users have complained about nfs-ganesha process getting stuck here - https://github.com/nfs-ganesha/nfs-ganesha/issues/335
REVIEW: https://review.gluster.org/22436 (gfapi: Unblock epoll thread for upcall processing) posted (#1) for review on master by soumya k
REVIEW: https://review.gluster.org/22436 (gfapi: Unblock epoll thread for upcall processing) merged (#4) on master by Amar Tumballi