+++ This bug was initially created as a clone of Bug #1693575 +++
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:
--- Additional comment from Soumya Koduri on 2019-03-28 09:28:58 UTC ---
Users have complained about nfs-ganesha process getting stuck here - https://github.com/nfs-ganesha/nfs-ganesha/issues/335
--- Additional comment from Worker Ant on 2019-03-28 09:34:11 UTC ---
REVIEW: https://review.gluster.org/22436 (gfapi: Unblock epoll thread for upcall processing) posted (#1) for review on master by soumya k
--- Additional comment from Worker Ant on 2019-03-29 07:25:10 UTC ---
REVIEW: https://review.gluster.org/22436 (gfapi: Unblock epoll thread for upcall processing) merged (#4) on master by Amar Tumballi
REVIEW: https://review.gluster.org/22461 (gfapi: Unblock epoll thread for upcall processing) posted (#1) for review on release-4.1 by soumya k
REVIEW: https://review.gluster.org/22461 (gfapi: Unblock epoll thread for upcall processing) merged (#2) on release-4.1 by Shyamsundar Ranganathan
This bug is getting closed because a release has been made available that should address the reported issue. In case the problem is still not fixed with glusterfs-4.1.9, please open a new bug report.
glusterfs-4.1.9 has been announced on the Gluster mailinglists , packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist  and the update infrastructure for your distribution.
Note that for this issue to be properly fixed the following patches need to be backported to glusterfs 4.1.x branch aswell:
"gfapi: fix incorrect initialization of upcall syncop arguments":
"Upcall: Avoid sending upcalls for invalid Inode":