Thanks for your quick reply! >>Without looking at this case in detail: >>Delegations are granted at the server's discretion, so this certainly >>isn't a bug. Got it. >>It might be suboptimal behavior. If there's evidence that this causes >>significant regressions on some important workload, then we'd want to >>look into fixing it. If I understand the case correctly, the most common workload it influences like: One nfs client opens a file with flag O_WRONLY/O_RDWR, close it. Then some nfs clients open the file with O_RDONLY right now then it will prevent server to give any delegation to other clients. It may cause many unnecessary requests from clients because lack of delegations. -- Su >>--b. ________________________________________ From: J. Bruce Fields <bfields@xxxxxxxxxxxx> Sent: Tuesday, December 14, 2021 5:55 To: Su, Yue/苏 越 Cc: linux-nfs@xxxxxxxxxxxxxxx; jlayton@xxxxxxxxxx; trond.myklebust@xxxxxxxxxxxxxxx; bfields@xxxxxxxxxx Subject: Re: [bug report] nfs clients fail to get read delegations after file open with O_RDWR On Mon, Dec 13, 2021 at 03:39:26AM +0000, suy.fnst@xxxxxxxxxxx wrote: > So I wonder if it's a real regression/bug or an expected "cost" of speedup on > nfsd file caches? Without looking at this case in detail: Delegations are granted at the server's discretion, so this certainly isn't a bug. It might be suboptimal behavior. If there's evidence that this causes significant regressions on some important workload, then we'd want to look into fixing it. --b.
