NFSv4: Send unmapped uid/gids to the server if the idmapper fails

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/idmap.c

@@ -52,6 +52,11 @@ static int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *re
 	return 1;
 }
 
+static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
+{
+	return snprintf(buf, buflen, "%u", id);
+}
+
 #ifdef CONFIG_NFS_USE_NEW_IDMAPPER
 
 #include <linux/slab.h>
@@ -252,11 +257,20 @@ int nfs_map_group_to_gid(struct nfs_client *clp, const char *name, size_t namele
 
 int nfs_map_uid_to_name(struct nfs_client *clp, __u32 uid, char *buf, size_t buflen)
 {
-	return nfs_idmap_lookup_name(uid, "user", buf, buflen);
+	int ret;
+	ret = nfs_idmap_lookup_name(uid, "user", buf, buflen);
+	if (ret < 0)
+		ret = nfs_map_numeric_to_string(uid, buf, buflen);
+	return ret;
 }
 int nfs_map_gid_to_group(struct nfs_client *clp, __u32 gid, char *buf, size_t buflen)
 {
-	return nfs_idmap_lookup_name(gid, "group", buf, buflen);
+	int ret;
+
+	ret = nfs_idmap_lookup_name(gid, "group", buf, buflen);
+	if (ret < 0)
+		ret = nfs_map_numeric_to_string(gid, buf, buflen);
+	return ret;
 }
 
 #else  /* CONFIG_NFS_USE_NEW_IDMAPPER not defined */
@@ -736,14 +750,22 @@ int nfs_map_group_to_gid(struct nfs_client *clp, const char *name, size_t namele
 int nfs_map_uid_to_name(struct nfs_client *clp, __u32 uid, char *buf, size_t buflen)
 {
 	struct idmap *idmap = clp->cl_idmap;
+	int ret;
 
-	return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
+	ret = nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
+	if (ret < 0)
+		ret = nfs_map_numeric_to_string(uid, buf, buflen);
+	return ret;
 }
 int nfs_map_gid_to_group(struct nfs_client *clp, __u32 uid, char *buf, size_t buflen)
 {
 	struct idmap *idmap = clp->cl_idmap;
+	int ret;
 
-	return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
+	ret = nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
+	if (ret < 0)
+		ret = nfs_map_numeric_to_string(uid, buf, buflen);
+	return ret;
 }
 
 #endif /* CONFIG_NFS_USE_NEW_IDMAPPER */