NFS mount option rdirplus

Hello Trond,

A customer is experiencing significant performance degradation after switching from Rocky Linux 8.7 clients to a 6.12 upstream kernel. The clients with the newer kernel are seeing a dramatic increase in GETATTR/LOOKUP operations. Their workload primarily involves traversing a read-only directory tree and reading or retrieving file attributes.

This issue is related to changes made to add heuristics to READDIRPLUS. We have been testing on RHEL 9.7 using the mount option 'rdirplus=force' to reduce the number of GETATTR/LOOKUP operations. However, this option introduces other issues.

Is it possible to add a mount option to completely bypass the readdir heuristics, such as 'rdirplus=legacy'? Alternatively, could a mount option be added to make the client less aggressive in sending READDIRPLUS requests, such as 'rdirplus=eager'?


--Jorge