diff --git a/opendkim/opendkim.c b/opendkim/opendkim.c
index fbfb8c0..b5ecd14 100644
--- a/opendkim/opendkim.c
+++ b/opendkim/opendkim.c
@@ -4710,17 +4710,27 @@ dkimf_checkfsnode(const char *path, uid_t myuid, char *myname, ino_t *ino)
 	if (status != 0)
 		return -1;
 
-	if ((s.st_mode & S_IFMT) == S_IFREG)
+syslog(LOG_DEBUG, "path %s, uid %u, gid %u, mode %08o, me %u", path, s.st_uid,
+       s.st_gid, s.st_mode, myuid);
+
+	if (S_ISREG(s.st_mode))
 	{
+syslog(LOG_DEBUG, "- regular file", path);
+
 		/* owned by root or by me */
 		if (s.st_uid != 0 && s.st_uid != myuid)
+{
+syslog(LOG_DEBUG, "- foreign owner");
 			return 0;
+}
 
 		/* if group read/write, the group is only me and/or root */
 		if ((s.st_mode & (S_IRGRP|S_IWGRP)) != 0)
 		{
 			int c;
 
+syslog(LOG_DEBUG, "- group read/write", path);
+
 			/* check if anyone else has this file's gid */
 			pthread_mutex_lock(&pwdb_lock);
 			setpwent();
@@ -4730,6 +4740,7 @@ dkimf_checkfsnode(const char *path, uid_t myuid, char *myname, ino_t *ino)
 				    pw->pw_uid != 0 &&
 				    s.st_gid == pw->pw_gid)
 				{
+syslog(LOG_DEBUG, "- user %s has same gid", pw->pw_name);
 					pthread_mutex_unlock(&pwdb_lock);
 					return 0;
 				}
@@ -4749,6 +4760,7 @@ dkimf_checkfsnode(const char *path, uid_t myuid, char *myname, ino_t *ino)
 				if (strcmp(gr->gr_mem[c], myname) != 0 &&
 				    strcmp(gr->gr_mem[c], SUPERUSER) != 0)
 				{
+syslog(LOG_DEBUG, "- user %s in same group %s", gr->gr_mem[c], gr->gr_name);
 					pthread_mutex_unlock(&pwdb_lock);
 					return 0;
 				}
@@ -4759,15 +4771,22 @@ dkimf_checkfsnode(const char *path, uid_t myuid, char *myname, ino_t *ino)
 
 		/* not read/write by others */
 		if ((s.st_mode & (S_IROTH|S_IWOTH)) != 0)
+{
+syslog(LOG_DEBUG, "- read/write by others");
 			return 0;
+}
 
 		*ino = s.st_ino;
 	}
-	else if ((s.st_mode & S_IFMT) == S_IFDIR)
+	else if (S_ISDIR(s.st_mode))
 	{
+syslog(LOG_DEBUG, "- directory", path);
 		/* other write needs to be off */
 		if ((s.st_mode & S_IWOTH) != 0)
+{
+syslog(LOG_DEBUG, "- writable by others", path);
 			return 0;
+}
 
 		/* group write needs to be super-user or me only */
 		if ((s.st_mode & S_IWGRP) != 0)
@@ -4783,6 +4802,7 @@ dkimf_checkfsnode(const char *path, uid_t myuid, char *myname, ino_t *ino)
 				    pw->pw_uid != 0 &&
 				    s.st_gid == pw->pw_gid)
 				{
+syslog(LOG_DEBUG, "- user %s has same gid", pw->pw_name);
 					pthread_mutex_unlock(&pwdb_lock);
 					return 0;
 				}
@@ -4801,6 +4821,7 @@ dkimf_checkfsnode(const char *path, uid_t myuid, char *myname, ino_t *ino)
 				if (strcmp(gr->gr_mem[c], myname) != 0 &&
 				    strcmp(gr->gr_mem[c], SUPERUSER) != 0)
 				{
+syslog(LOG_DEBUG, "- user %s in same group %s", gr->gr_mem[c], gr->gr_name);
 					pthread_mutex_unlock(&pwdb_lock);
 					return 0;
 				}
@@ -4812,7 +4833,10 @@ dkimf_checkfsnode(const char *path, uid_t myuid, char *myname, ino_t *ino)
 		/* owner write needs to be super-user or me only */
 		if ((s.st_mode & S_IWUSR) != 0 &&
 		    (s.st_uid != 0 && s.st_uid != myuid))
+{
+syslog(LOG_DEBUG, "- owner write for foreign uid");
 			return 0;
+}
 
 		/* if nobody else can execute below here, that's good enough */
 		if ((s.st_mode & (S_IXGRP|S_IXOTH)) == 0)