> On May 17, 2023, at 7:38 PM, Dai Ngo <dai.ngo@xxxxxxxxxx> wrote:
>
> This patch grants write delegation for OPEN with NFS4_SHARE_ACCESS_WRITE
> if there is no conflict with other OPENs.
>
> Write delegation conflict with another OPEN, REMOVE, RENAME and SETATTR
> are handled the same as read delegation using notify_change,
> try_break_deleg.
Very clean. A couple of suggestions, one is down below, and here is
the other:
I was thinking we should add one or two counters in fs/nfsd/stats.c
to track how often read and write delegations are offered, and
perhaps one to count the number of DELEGRETURN operations. What do
you think makes sense?
> Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4state.c | 24 ++++++++++++++++--------
> 1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 6e61fa3acaf1..09a9e16407f9 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1144,7 +1144,7 @@ static void block_delegations(struct knfsd_fh *fh)
>
> static struct nfs4_delegation *
> alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
> - struct nfs4_clnt_odstate *odstate)
> + struct nfs4_clnt_odstate *odstate, u32 dl_type)
> {
> struct nfs4_delegation *dp;
> long n;
> @@ -1170,7 +1170,7 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
> INIT_LIST_HEAD(&dp->dl_recall_lru);
> dp->dl_clnt_odstate = odstate;
> get_clnt_odstate(odstate);
> - dp->dl_type = NFS4_OPEN_DELEGATE_READ;
> + dp->dl_type = dl_type;
> dp->dl_retries = 1;
> dp->dl_recalled = false;
> nfsd4_init_cb(&dp->dl_recall, dp->dl_stid.sc_client,
> @@ -5451,6 +5451,7 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> struct nfs4_delegation *dp;
> struct nfsd_file *nf;
> struct file_lock *fl;
> + u32 deleg;
>
> /*
> * The fi_had_conflict and nfs_get_existing_delegation checks
> @@ -5460,7 +5461,13 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> if (fp->fi_had_conflict)
> return ERR_PTR(-EAGAIN);
>
> - nf = find_readable_file(fp);
> + if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
> + nf = find_writeable_file(fp);
> + deleg = NFS4_OPEN_DELEGATE_WRITE;
> + } else {
> + nf = find_readable_file(fp);
> + deleg = NFS4_OPEN_DELEGATE_READ;
> + }
> if (!nf) {
> /*
> * We probably could attempt another open and get a read
> @@ -5491,11 +5498,11 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> return ERR_PTR(status);
>
> status = -ENOMEM;
> - dp = alloc_init_deleg(clp, fp, odstate);
> + dp = alloc_init_deleg(clp, fp, odstate, deleg);
> if (!dp)
> goto out_delegees;
>
> - fl = nfs4_alloc_init_lease(dp, NFS4_OPEN_DELEGATE_READ);
> + fl = nfs4_alloc_init_lease(dp, deleg);
> if (!fl)
> goto out_clnt_odstate;
>
> @@ -5583,6 +5590,7 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> struct svc_fh *parent = NULL;
> int cb_up;
> int status = 0;
> + u32 wdeleg = false;
>
> cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
> open->op_recall = 0;
> @@ -5590,8 +5598,6 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> case NFS4_OPEN_CLAIM_PREVIOUS:
> if (!cb_up)
> open->op_recall = 1;
> - if (open->op_delegate_type != NFS4_OPEN_DELEGATE_READ)
> - goto out_no_deleg;
> break;
> case NFS4_OPEN_CLAIM_NULL:
> parent = currentfh;
> @@ -5617,7 +5623,9 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
>
> trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
I'd like you to add a trace_nfsd_deleg_write(), and invoke
it here instead of trace_nfsd_deleg_read when NFSD hands out
a write delegation.
> - open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
> + wdeleg = open->op_share_access & NFS4_SHARE_ACCESS_WRITE;
> + open->op_delegate_type = wdeleg ?
> + NFS4_OPEN_DELEGATE_WRITE : NFS4_OPEN_DELEGATE_READ;
> nfs4_put_stid(&dp->dl_stid);
> return;
> out_no_deleg:
> --
> 2.9.5
>
--
Chuck Lever
