I need to know if both the clients are mounting the share in rw mode.
??? Yes of course!
The 2 clients have the same fstab; it is in the line concerning the server, I have worked many: actimeo=0, transport=tcp, and many other tests!
I don't remember. The only effect is theses flags degrade the perf.
Basicly, the /ext/exports contains only the share disk name
/NFS_SHARE
or
/NFS_SHARE sync
None of the flags I have tried, did solve the problem
and i am on this pb from many months