sanlock: Re-add lockspace unconditionally

Currently, if sanlock is already registering a lockspace other
libvirtd instances (from other hosts) obtain -EINPROGRESS. On
sufficiently new sanlock, sanlock_inq_lockspace() is called,
which suspend execution until lockspace state is changed. With
current libvirt implementation, we fail to retry adding the
lockspace again but continue in error path. Therefore we produce
meaningless error message:

virLockManagerSanlockSetupLockspace:363 : Unable to add lockspace
/var/lib/libvirt/sanlock/__LIBVIRT__DISKS__: Success
qemudLoadDriverConfig:558 : Failed to load lock manager sanlock

We should try to re-add the lockspace after its state change to
be sure it was added successfully. In fact, with sufficiently new
sanlock we can just avoid dummy usleep() which is used if there's
no inquire API.

src/locking/lock_driver_sanlock.c

@@ -197,9 +197,7 @@ static int virLockManagerSanlockSetupLockspace(void)
     struct sanlk_lockspace ls;
     char *path = NULL;
     char *dir = NULL;
-#ifndef HAVE_SANLOCK_INQ_LOCKSPACE
     int retries = LOCKSPACE_RETRIES;
-#endif
 
     if (virAsprintf(&path, "%s/%s",
                     driver->autoDiskLeasePath,
@@ -332,25 +330,23 @@ static int virLockManagerSanlockSetupLockspace(void)
      * either call a sanlock API that blocks us until lockspace changes state,
      * or we can fallback to polling.
      */
-#ifndef HAVE_SANLOCK_INQ_LOCKSPACE
 retry:
-#endif
     if ((rv = sanlock_add_lockspace(&ls, 0)) < 0) {
-        if (-rv == EINPROGRESS) {
+        if (-rv == EINPROGRESS && --retries) {
 #ifdef HAVE_SANLOCK_INQ_LOCKSPACE
             /* we have this function which blocks until lockspace change the
              * state. It returns 0 if lockspace has been added, -ENOENT if it
-             * hasn't. XXX should we goto retry? */
+             * hasn't. */
             VIR_DEBUG("Inquiring lockspace");
-            rv = sanlock_inq_lockspace(&ls, SANLK_INQ_WAIT);
+            if (sanlock_inq_lockspace(&ls, SANLK_INQ_WAIT) < 0)
+                VIR_DEBUG("Unable to inquire lockspace");
 #else
             /* fall back to polling */
-            if (retries--) {
-                usleep(LOCKSPACE_SLEEP * 1000);
-                VIR_DEBUG("Retrying to add lockspace (left %d)", retries);
-                goto retry;
-            }
+            VIR_DEBUG("Sleeping for %dms", LOCKSPACE_SLEEP);
+            usleep(LOCKSPACE_SLEEP * 1000);
 #endif
+            VIR_DEBUG("Retrying to add lockspace (left %d)", retries);
+            goto retry;
         }
         if (-rv != EEXIST) {
             if (rv <= -200)