1 files changed, 49 insertions, 11 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index f8d50817fafc..61dfb33f0559 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4576,6 +4576,9 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
 static struct file *
 nfs4_find_file(struct nfs4_stid *s, int flags)
 {
+	if (!s)
+		return NULL;
+
 	switch (s->sc_type) {
 	case NFS4_DELEG_STID:
 		if (WARN_ON_ONCE(!s->sc_file->fi_deleg_file))
@@ -4607,27 +4610,63 @@ nfs4_check_olstateid(struct svc_fh *fhp, struct nfs4_ol_stateid *ols, int flags)
 	return nfs4_check_openmode(ols, flags);
 }
 
+static __be32
+nfs4_check_file(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfs4_stid *s,
+		struct file **filpp, bool *tmp_file, int flags)
+{
+	int acc = (flags & RD_STATE) ? NFSD_MAY_READ : NFSD_MAY_WRITE;
+	struct file *file;
+	__be32 status;
+
+	file = nfs4_find_file(s, flags);
+	if (file) {
+		status = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
+				acc | NFSD_MAY_OWNER_OVERRIDE);
+		if (status) {
+			fput(file);
+			return status;
+		}
+
+		*filpp = file;
+	} else {
+		status = nfsd_open(rqstp, fhp, S_IFREG, acc, filpp);
+		if (status)
+			return status;
+
+		if (tmp_file)
+			*tmp_file = true;
+	}
+
+	return 0;
+}
+
 /*
  * Checks for stateid operations
  */
 __be32
-nfs4_preprocess_stateid_op(struct net *net, struct nfsd4_compound_state *cstate,
-			   stateid_t *stateid, int flags, struct file **filpp)
+nfs4_preprocess_stateid_op(struct svc_rqst *rqstp,
+		struct nfsd4_compound_state *cstate, stateid_t *stateid,
+		int flags, struct file **filpp, bool *tmp_file)
 {
 	struct svc_fh *fhp = &cstate->current_fh;
 	struct inode *ino = d_inode(fhp->fh_dentry);
+	struct net *net = SVC_NET(rqstp);
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
-	struct nfs4_stid *s;
+	struct nfs4_stid *s = NULL;
 	__be32 status;
 
 	if (filpp)
 		*filpp = NULL;
+	if (tmp_file)
+		*tmp_file = false;
 
 	if (grace_disallows_io(net, ino))
 		return nfserr_grace;
 
-	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
-		return check_special_stateids(net, fhp, stateid, flags);
+	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid)) {
+		status = check_special_stateids(net, fhp, stateid, flags);
+		goto done;
+	}
 
 	status = nfsd4_lookup_stateid(cstate, stateid,
 				NFS4_DELEG_STID|NFS4_OPEN_STID|NFS4_LOCK_STID,
@@ -4652,13 +4691,12 @@ nfs4_preprocess_stateid_op(struct net *net, struct nfsd4_compound_state *cstate,
 		break;
 	}
 
-	if (!status && filpp) {
-		*filpp = nfs4_find_file(s, flags);
-		if (!*filpp)
-			status = nfserr_serverfault;
-	}
+done:
+	if (!status && filpp)
+		status = nfs4_check_file(rqstp, fhp, s, filpp, tmp_file, flags);
 out:
-	nfs4_put_stid(s);
+	if (s)
+		nfs4_put_stid(s);
 	return status;
 }