On Tue, 2024-10-08 at 09:57 -0700, Dai Ngo wrote:
> After the delegation is returned to the NFS server remove it
> from the server's delegations list to reduce the time it takes
> to scan this list.
>
> Piggyback the state manager's run to return marked delegations
> for this job.
>
> Network trace captured while running the below script shows the
> time taken to service the CB_RECALL increases gradually due to
> the overhead of traversing the delegation list in
> nfs_delegation_find_inode_server.
>
> The NFS server in this test is a Solaris server which issues
> CB_RECALL when receiving the all-zero stateid in the SETATTR.
>
> #!/bin/sh
>
> mount=/mnt/data
> for i in $(seq 1 20)
> do
> echo $i
> mkdir $mount/testtarfile$i
> time tar -C $mount/testtarfile$i -xf 5000_files.tar
> done
>
> Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> ---
> fs/nfs/delegation.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
> index 20cb2008f9e4..65b10f7ea232 100644
> --- a/fs/nfs/delegation.c
> +++ b/fs/nfs/delegation.c
> @@ -642,6 +642,17 @@ static int
> nfs_server_return_marked_delegations(struct nfs_server *server,
>
> if (test_bit(NFS_DELEGATION_INODE_FREEING,
> &delegation->flags))
> continue;
> + if (test_bit(NFS_DELEGATION_REVOKED, &delegation-
> >flags)) {
> + inode =
> nfs_delegation_grab_inode(delegation);
> + if (inode) {
> + rcu_read_unlock();
> + if
> (nfs_detach_delegation(NFS_I(inode), delegation, server))
> + nfs_put_delegation(delegatio
> n);
> + iput(inode);
> + cond_resched();
> + goto restart;
> + }
> + }
> if (!nfs_delegation_need_return(delegation)) {
> if (nfs4_is_valid_delegation(delegation, 0))
> prev = delegation;
This is not the right place to garbage collect revoked delegations.
We can do something like the above in nfs_revoke_delegation() and in
nfs_delegation_mark_returned() instead.
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx
