nfsd4: clean up nfs4_open_delegation

The nfs4_open_delegation logic is unecessarily baroque.

Also stop pretending we support write delegations in several places.

Some day we will support write delegations, but when that happens adding
back in these flag parameters will be the easy part.  For now they're
just confusing.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -364,19 +364,12 @@ static struct nfs4_ol_stateid * nfs4_alloc_stateid(struct nfs4_client *clp)
 }
 
 static struct nfs4_delegation *
-alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct svc_fh *current_fh, u32 type)
+alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct svc_fh *current_fh)
 {
 	struct nfs4_delegation *dp;
 	struct nfs4_file *fp = stp->st_file;
 
 	dprintk("NFSD alloc_init_deleg\n");
-	/*
-	 * Major work on the lease subsystem (for example, to support
-	 * calbacks on stat) will be required before we can support
-	 * write delegations properly.
-	 */
-	if (type != NFS4_OPEN_DELEGATE_READ)
-		return NULL;
 	if (fp->fi_had_conflict)
 		return NULL;
 	if (num_delegations > max_delegations)
@@ -397,7 +390,7 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv
 	INIT_LIST_HEAD(&dp->dl_recall_lru);
 	get_nfs4_file(fp);
 	dp->dl_file = fp;
-	dp->dl_type = type;
+	dp->dl_type = NFS4_OPEN_DELEGATE_READ;
 	fh_copy_shallow(&dp->dl_fh, &current_fh->fh_handle);
 	dp->dl_time = 0;
 	atomic_set(&dp->dl_count, 1);
@@ -3020,13 +3013,13 @@ static struct file_lock *nfs4_alloc_init_lease(struct nfs4_delegation *dp, int f
 	return fl;
 }
 
-static int nfs4_setlease(struct nfs4_delegation *dp, int flag)
+static int nfs4_setlease(struct nfs4_delegation *dp)
 {
 	struct nfs4_file *fp = dp->dl_file;
 	struct file_lock *fl;
 	int status;
 
-	fl = nfs4_alloc_init_lease(dp, flag);
+	fl = nfs4_alloc_init_lease(dp, NFS4_OPEN_DELEGATE_READ);
 	if (!fl)
 		return -ENOMEM;
 	fl->fl_file = find_readable_file(fp);
@@ -3044,12 +3037,12 @@ static int nfs4_setlease(struct nfs4_delegation *dp, int flag)
 	return 0;
 }
 
-static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag)
+static int nfs4_set_delegation(struct nfs4_delegation *dp)
 {
 	struct nfs4_file *fp = dp->dl_file;
 
 	if (!fp->fi_lease)
-		return nfs4_setlease(dp, flag);
+		return nfs4_setlease(dp);
 	spin_lock(&recall_lock);
 	if (fp->fi_had_conflict) {
 		spin_unlock(&recall_lock);
@@ -3085,6 +3078,9 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
 
 /*
  * Attempt to hand out a delegation.
+ *
+ * Note we don't support write delegations, and won't until the vfs has
+ * proper support for them.
  */
 static void
 nfs4_open_delegation(struct net *net, struct svc_fh *fh,
@@ -3093,26 +3089,26 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
 	struct nfs4_delegation *dp;
 	struct nfs4_openowner *oo = container_of(stp->st_stateowner, struct nfs4_openowner, oo_owner);
 	int cb_up;
-	int status = 0, flag = 0;
+	int status = 0;
 
 	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
-	flag = NFS4_OPEN_DELEGATE_NONE;
 	open->op_recall = 0;
 	switch (open->op_claim_type) {
 		case NFS4_OPEN_CLAIM_PREVIOUS:
 			if (!cb_up)
 				open->op_recall = 1;
-			flag = open->op_delegate_type;
-			if (flag == NFS4_OPEN_DELEGATE_NONE)
-				goto out;
+			if (open->op_delegate_type != NFS4_OPEN_DELEGATE_READ)
+				goto out_no_deleg;
 			break;
 		case NFS4_OPEN_CLAIM_NULL:
-			/* Let's not give out any delegations till everyone's
-			 * had the chance to reclaim theirs.... */
+			/*
+			 * Let's not give out any delegations till everyone's
+			 * had the chance to reclaim theirs....
+			 */
 			if (locks_in_grace(net))
-				goto out;
+				goto out_no_deleg;
 			if (!cb_up || !(oo->oo_flags & NFS4_OO_CONFIRMED))
-				goto out;
+				goto out_no_deleg;
 			/*
 			 * Also, if the file was opened for write or
 			 * create, there's a good chance the client's
@@ -3121,20 +3117,17 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
 			 * write delegations):
 			 */
 			if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
-				flag = NFS4_OPEN_DELEGATE_WRITE;
-			else if (open->op_create == NFS4_OPEN_CREATE)
-				flag = NFS4_OPEN_DELEGATE_WRITE;
-			else
-				flag = NFS4_OPEN_DELEGATE_READ;
+				goto out_no_deleg;
+			if (open->op_create == NFS4_OPEN_CREATE)
+				goto out_no_deleg;
 			break;
 		default:
-			goto out;
+			goto out_no_deleg;
 	}
-
-	dp = alloc_init_deleg(oo->oo_owner.so_client, stp, fh, flag);
+	dp = alloc_init_deleg(oo->oo_owner.so_client, stp, fh);
 	if (dp == NULL)
 		goto out_no_deleg;
-	status = nfs4_set_delegation(dp, flag);
+	status = nfs4_set_delegation(dp);
 	if (status)
 		goto out_free;
 
@@ -3142,9 +3135,13 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
 
 	dprintk("NFSD: delegation stateid=" STATEID_FMT "\n",
 		STATEID_VAL(&dp->dl_stid.sc_stateid));
-out:
-	open->op_delegate_type = flag;
-	if (flag == NFS4_OPEN_DELEGATE_NONE) {
+	open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
+	return;
+out_free:
+	unhash_stid(&dp->dl_stid);
+	nfs4_put_delegation(dp);
+out_no_deleg:
+	open->op_delegate_type = 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");
@@ -3152,14 +3149,7 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
 	/* 4.1 client asking for a delegation? */
 	if (open->op_deleg_want)
 		nfsd4_open_deleg_none_ext(open, status);
-	}
 	return;
-out_free:
-	unhash_stid(&dp->dl_stid);
-	nfs4_put_delegation(dp);
-out_no_deleg:
-	flag = NFS4_OPEN_DELEGATE_NONE;
-	goto out;
 }
 
 static void nfsd4_deleg_xgrade_none_ext(struct nfsd4_open *open,