On 2011-10-20 08:47, J. Bruce Fields wrote:
> On Thu, Oct 20, 2011 at 12:36:25PM +0000, Benny Halevy wrote:
>> OK, I read you. Just please take note that WANT_NO_DELEG flag is important to simplified clients that do not support delegations, like the one I was testing against in the BAT, and it is the only one in use that I could tell.
>
> If you can suggest an implementation that meets the minimum required by
> the spec, I'd happily take it....
>
> It might not be much harder: it's probably just a matter of returrning
> the right OPEN_DELEGATE_NONE_EXT?
>
> Though unfortunately there's not a "why" for "I just didn't feel like
> giving you one", so we probably would have to make an effort to detect
> the different case.
Agreed. It could have been a good to have such a reason.
>
> Also, I wonder if it's wise for a client to depend on this--it really is
> an optional feature as far as I can tell. It would be safer to teach
> the client just to handle delegations in the simplest way possible
> (possibly just return them immediately?).
>
That's true.
How about the following? (untested squashme over this patch)
>From ab9e79564fee05a0f3f369fc134bbace1543ac4d Mon Sep 17 00:00:00 2001
From: Benny Halevy <bhalevy@xxxxxxxxxx>
Date: Thu, 20 Oct 2011 08:00:03 -0700
Subject: [PATCH] SQUASHME: nfsd4: implement why_no_deleg
Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 50 +++++++++++++++++++++++++++++++++++++++++++++-----
fs/nfsd/nfs4xdr.c | 7 ++++++-
fs/nfsd/xdr4.h | 1 +
3 files changed, 52 insertions(+), 6 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index d00c246..2cdd2b3 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2914,7 +2914,7 @@ static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag)
struct nfs4_delegation *dp;
struct nfs4_openowner *oo = container_of(stp->st_stateowner, struct nfs4_openowner, oo_owner);
int cb_up;
- int status, flag = 0;
+ int status = 0, flag = 0;
cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
flag = NFS4_OPEN_DELEGATE_NONE;
@@ -2955,11 +2955,32 @@ static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag)
dprintk("NFSD: delegation stateid=" STATEID_FMT "\n",
STATEID_VAL(&dp->dl_stid.sc_stateid));
out:
- if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS
- && flag == NFS4_OPEN_DELEGATE_NONE
- && open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE)
- dprintk("NFSD: WARNING: refusing delegation reclaim\n");
open->op_delegate_type = flag;
+ if (flag == NFS4_OPEN_DELEGATE_NONE) {
+ if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS &&
+ open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE)
+ dprintk("NFSD: WARNING: refusing delegation reclaim\n");
+
+ if (open->op_deleg_want) {
+ open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+ if (status == -EAGAIN)
+ open->op_why_no_deleg = WND4_CONTENTION;
+ else {
+ open->op_why_no_deleg = WND4_RESOURCE;
+ switch (open->op_deleg_want) {
+ case NFS4_SHARE_WANT_READ_DELEG:
+ case NFS4_SHARE_WANT_WRITE_DELEG:
+ case NFS4_SHARE_WANT_ANY_DELEG:
+ break;
+ case NFS4_SHARE_WANT_CANCEL:
+ open->op_why_no_deleg = WND4_CANCELLED;
+ break;
+ case NFS4_SHARE_WANT_NO_DELEG:
+ BUG(); /* not supposed to get here */
+ }
+ }
+ }
+ }
return;
out_free:
nfs4_put_delegation(dp);
@@ -3036,6 +3057,7 @@ static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag)
if (open->op_deleg_want & NFS4_SHARE_WANT_NO_DELEG) {
open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+ open->op_why_no_deleg = WND4_NOT_WANTED;
goto nodeleg;
}
}
@@ -3051,6 +3073,24 @@ static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag)
dprintk("%s: stateid=" STATEID_FMT "\n", __func__,
STATEID_VAL(&stp->st_stid.sc_stateid));
out:
+ /* 4.1 client trying to upgrade/downgrade delegation? */
+ if (open->op_delegate_type == NFS4_OPEN_DELEGATE_NONE && dp &&
+ open->op_deleg_want) {
+ if (open->op_deleg_want == NFS4_SHARE_WANT_READ_DELEG &&
+ dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
+ open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+ open->op_why_no_deleg = WND4_NOT_SUPP_DOWNGRADE;
+ } else if (open->op_deleg_want == NFS4_SHARE_WANT_WRITE_DELEG &&
+ dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
+ open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+ open->op_why_no_deleg = WND4_NOT_SUPP_DOWNGRADE;
+ }
+ /* Otherwise the client must be confused wanting a delegation
+ * it already has, therefore we don't return
+ * NFS4_OPEN_DELEGATE_NONE_EXT and reason.
+ */
+ }
+
if (fp)
put_nfs4_file(fp);
if (status == 0 && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 9b838e9..f2c1338 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3035,7 +3035,12 @@ static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp,
ADJUST_ARGS();
break;
case NFS4_OPEN_DELEGATE_NONE_EXT: /* 4.1 */
- WRITE32(WND4_NOT_WANTED); /* only reason for now */
+ WRITE32(open->op_why_no_deleg);
+ switch (open->op_why_no_deleg) {
+ case WND4_CONTENTION:
+ case WND4_RESOURCE:
+ WRITE32(0); /* deleg signaling not supported yet */
+ }
break;
default:
BUG();
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 1e5ca95..d20d87e 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -214,6 +214,7 @@ struct nfsd4_open {
struct xdr_netobj op_fname; /* request - everything but CLAIM_PREV */
u32 op_delegate_type; /* request - CLAIM_PREV only */
stateid_t op_delegate_stateid; /* request - response */
+ u32 op_why_no_deleg; /* response - DELEG_NONE_EXT only */
u32 op_create; /* request */
u32 op_createmode; /* request */
u32 op_bmval[3]; /* request */
--
1.7.6
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