(lock_superlock): Delete superlock file if it stayed

locked for 20 seconds.

diff --git a/src/filelock.c b/src/filelock.c
index 5393867063c96d4e84889806e3f9fec53d4dd0f8..6c1b6b2a1c4dfee6c5c613ed54ea42bed173cf09 100644 (file)
--- a/src/filelock.c
+++ b/src/filelock.c
@@ -353,32 +353,64 @@ lock_superlock (lfname)
 {
   register int i, fd;
   DIR *lockdir;
+  struct stat first_stat, last_stat;
 
-  for (i = -20; i < 0 && (fd = open (superlock_file,
-                                    O_WRONLY | O_EXCL | O_CREAT, 0666)) < 0;
+  for (i = -20; i < 0;
        i++)
     {
+      fd = open (superlock_file,
+                O_WRONLY | O_EXCL | O_CREAT, 0666);
+
+      /* If we succeeded in creating the superlock, we win.
+        Fill in our info and return.  */
+      if (fd >= 0)
+       {
+#ifdef USG
+         chmod (superlock_file, 0666);
+#else
+         fchmod (fd, 0666);
+#endif
+         write (fd, lfname, strlen (lfname));
+         close (fd);
+         return;
+       }
+
+      /* If the problem is not just that it is already locked,
+        give up.  */
       if (errno != EEXIST)
        return;
 
+      message ("Superlock file exists, retrying...");
+
+      if (i == -20)
+       stat (superlock_file, &first_stat);
+
+      if (i == -1)
+       stat (superlock_file, &last_stat);
+
       /* This seems to be necessary to prevent Emacs from hanging when the
         competing process has already deleted the superlock, but it's still
         in the NFS cache.  So we force NFS to synchronize the cache.  */
-      if (lockdir = opendir (lock_dir))
+      lockdir = opendir (lock_dir);
+
+      if (lockdir)
        closedir (lockdir);
 
       sleep (1);
     }
-  if (fd >= 0)
+
+  if (first_stat.st_ctime == last_stat.st_ctime)
     {
-#ifdef USG
-      chmod (superlock_file, 0666);
-#else
-      fchmod (fd, 0666);
-#endif
-      write (fd, lfname, strlen (lfname));
-      close (fd);
+      int value;
+      value = unlink (superlock_file);
+
+      if (value != -1)
+       message ("Superlock file deleted");
+      else
+       message ("Failed to delete superlock file");
     }
+  else
+    message ("Giving up on the superlock file");
 }
 
 void