+static __be32
+nfsd4_verify_open_stid(struct nfs4_stid *s)
+{
+ __be32 ret = nfs_ok;
+
+ switch (s->sc_type) {
+ default:
+ break;
+ case NFS4_CLOSED_STID:
+ case NFS4_CLOSED_DELEG_STID:
+ ret = nfserr_bad_stateid;
+ break;
+ case NFS4_REVOKED_DELEG_STID:
+ ret = nfserr_deleg_revoked;
+ }
+ return ret;
+}
+
+/* Lock the stateid st_mutex, and deal with races with CLOSE */
+static __be32
+nfsd4_lock_ol_stateid(struct nfs4_ol_stateid *stp)
+{
+ __be32 ret;
+
+ mutex_lock(&stp->st_mutex);
+ ret = nfsd4_verify_open_stid(&stp->st_stid);
+ if (ret != nfs_ok)
+ mutex_unlock(&stp->st_mutex);
+ return ret;
+}
+
+static struct nfs4_ol_stateid *
+nfsd4_find_and_lock_existing_open(struct nfs4_file *fp, struct nfsd4_open *open)
+{
+ struct nfs4_ol_stateid *stp;
+ for (;;) {
+ spin_lock(&fp->fi_lock);
+ stp = nfsd4_find_existing_open(fp, open);
+ spin_unlock(&fp->fi_lock);
+ if (!stp || nfsd4_lock_ol_stateid(stp) == nfs_ok)
+ break;
+ nfs4_put_stid(&stp->st_stid);
+ }
+ return stp;
+}
+