NFSv4 reduce attribute requests for open reclaim

We currently make no distinction in attribute requests between normal OPENs
and OPEN with CLAIM_PREVIOUS.  This offers more possibility of failures in
the GETATTR response which foils OPEN reclaim attempts.

Reduce the requested attributes to the bare minimum needed to update the
reclaim open stateid and split nfs4_opendata_to_nfs4_state processing
accordingly.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4proc.c

@@ -152,6 +152,12 @@ static const u32 nfs4_pnfs_open_bitmap[3] = {
 	FATTR4_WORD2_MDSTHRESHOLD
 };
 
+static const u32 nfs4_open_noattr_bitmap[3] = {
+	FATTR4_WORD0_TYPE
+	| FATTR4_WORD0_CHANGE
+	| FATTR4_WORD0_FILEID,
+};
+
 const u32 nfs4_statfs_bitmap[2] = {
 	FATTR4_WORD0_FILES_AVAIL
 	| FATTR4_WORD0_FILES_FREE
@@ -1126,35 +1132,15 @@ static struct nfs4_state *nfs4_try_open_cached(struct nfs4_opendata *opendata)
 	return state;
 }
 
-static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
+static void
+nfs4_opendata_check_deleg(struct nfs4_opendata *data, struct nfs4_state *state)
 {
-	struct inode *inode;
-	struct nfs4_state *state = NULL;
+	struct nfs_client *clp = NFS_SERVER(state->inode)->nfs_client;
 	struct nfs_delegation *delegation;
-	int ret;
-
-	if (!data->rpc_done) {
-		state = nfs4_try_open_cached(data);
-		goto out;
-	}
-
-	ret = -EAGAIN;
-	if (!(data->f_attr.valid & NFS_ATTR_FATTR))
-		goto err;
-	inode = nfs_fhget(data->dir->d_sb, &data->o_res.fh, &data->f_attr);
-	ret = PTR_ERR(inode);
-	if (IS_ERR(inode))
-		goto err;
-	ret = -ENOMEM;
-	state = nfs4_get_open_state(inode, data->owner);
-	if (state == NULL)
-		goto err_put_inode;
-	if (data->o_res.delegation_type != 0) {
-		struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 	int delegation_flags = 0;
 
 	rcu_read_lock();
-		delegation = rcu_dereference(NFS_I(inode)->delegation);
+	delegation = rcu_dereference(NFS_I(state->inode)->delegation);
 	if (delegation)
 		delegation_flags = delegation->flags;
 	rcu_read_unlock();
@@ -1171,8 +1157,75 @@ static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data
 		nfs_inode_reclaim_delegation(state->inode,
 					     data->owner->so_cred,
 					     &data->o_res);
+}
+
+/*
+ * Check the inode attributes against the CLAIM_PREVIOUS returned attributes
+ * and update the nfs4_state.
+ */
+static struct nfs4_state *
+_nfs4_opendata_reclaim_to_nfs4_state(struct nfs4_opendata *data)
+{
+	struct inode *inode = data->state->inode;
+	struct nfs4_state *state = data->state;
+	int ret;
+
+	if (!data->rpc_done) {
+		ret = data->rpc_status;
+		goto err;
 	}
 
+	ret = -ESTALE;
+	if (!(data->f_attr.valid & NFS_ATTR_FATTR_TYPE) ||
+	    !(data->f_attr.valid & NFS_ATTR_FATTR_FILEID) ||
+	    !(data->f_attr.valid & NFS_ATTR_FATTR_CHANGE))
+		goto err;
+
+	ret = -ENOMEM;
+	state = nfs4_get_open_state(inode, data->owner);
+	if (state == NULL)
+		goto err;
+
+	ret = nfs_refresh_inode(inode, &data->f_attr);
+	if (ret)
+		goto err;
+
+	if (data->o_res.delegation_type != 0)
+		nfs4_opendata_check_deleg(data, state);
+	update_open_stateid(state, &data->o_res.stateid, NULL,
+			    data->o_arg.fmode);
+
+	return state;
+err:
+	return ERR_PTR(ret);
+
+}
+
+static struct nfs4_state *
+_nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
+{
+	struct inode *inode;
+	struct nfs4_state *state = NULL;
+	int ret;
+
+	if (!data->rpc_done) {
+		state = nfs4_try_open_cached(data);
+		goto out;
+	}
+
+	ret = -EAGAIN;
+	if (!(data->f_attr.valid & NFS_ATTR_FATTR))
+		goto err;
+	inode = nfs_fhget(data->dir->d_sb, &data->o_res.fh, &data->f_attr);
+	ret = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto err;
+	ret = -ENOMEM;
+	state = nfs4_get_open_state(inode, data->owner);
+	if (state == NULL)
+		goto err_put_inode;
+	if (data->o_res.delegation_type != 0)
+		nfs4_opendata_check_deleg(data, state);
 	update_open_stateid(state, &data->o_res.stateid, NULL,
 			data->o_arg.fmode);
 	iput(inode);
@@ -1184,6 +1237,14 @@ static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data
 	return ERR_PTR(ret);
 }
 
+static struct nfs4_state *
+nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
+{
+	if (data->o_arg.claim == NFS4_OPEN_CLAIM_PREVIOUS)
+		return _nfs4_opendata_reclaim_to_nfs4_state(data);
+	return _nfs4_opendata_to_nfs4_state(data);
+}
+
 static struct nfs_open_context *nfs4_state_find_open_context(struct nfs4_state *state)
 {
 	struct nfs_inode *nfsi = NFS_I(state->inode);
@@ -1505,6 +1566,7 @@ static void nfs4_open_prepare(struct rpc_task *task, void *calldata)
 	data->o_arg.clientid = sp->so_server->nfs_client->cl_clientid;
 	if (data->o_arg.claim == NFS4_OPEN_CLAIM_PREVIOUS) {
 		task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_NOATTR];
+		data->o_arg.open_bitmap = &nfs4_open_noattr_bitmap[0];
 		nfs_copy_fh(&data->o_res.fh, data->o_arg.fh);
 	}
 	data->timestamp = jiffies;

fs/nfs/nfs4xdr.c

@@ -2264,7 +2264,7 @@ static void nfs4_xdr_enc_open_noattr(struct rpc_rqst *req,
 	encode_open(xdr, args, &hdr);
 	if (args->access)
 		encode_access(xdr, args->access, &hdr);
-	encode_getfattr(xdr, args->bitmask, &hdr);
+	encode_getfattr_open(xdr, args->bitmask, args->open_bitmap, &hdr);
 	encode_nops(&hdr);
 }