[PATCH 03/14] libxl: suspend: Return correct error from callbacks

[Ian Jackson <ian.jackson@eu.citrix.com>]

If a suspend callback fails, it has a libxl error code in its hand.
However we must return to libxc the values that libxc expects.  So we
stash the libxl error code in dss->rc and fish it out again after
libxc returns from the suspend call.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
---
 tools/libxl/libxl_dom.c      |   14 +++++++++++++-
 tools/libxl/libxl_internal.h |    1 +
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 65a88c2..0fda9a4 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -869,6 +869,7 @@ static void domain_suspend_switch_qemu_xen_logdirty
         libxl__xc_domain_saverestore_async_callback_done(egc, shs, 0);
     } else {
         LOG(ERROR,"logdirty switch failed (rc=%d), aborting suspend",rc);
+        dss->rc = rc;
         libxl__xc_domain_saverestore_async_callback_done(egc, shs, -1);
     }
 }
@@ -891,6 +892,7 @@ void libxl__domain_suspend_common_switch_qemu_logdirty
     default:
         LOG(ERROR,"logdirty switch failed"
             ", no valid device model version found, aborting suspend");
+        dss->rc = ERROR_FAIL;
         libxl__xc_domain_saverestore_async_callback_done(egc, shs, -1);
     }
 }
@@ -972,6 +974,7 @@ static void switch_logdirty_done(libxl__egc *egc,
     int broke;
     if (rc) {
         broke = -1;
+        dss->rc = rc;
     } else {
         broke = 0;
     }
@@ -1414,6 +1417,7 @@ static void libxl__domain_suspend_callback(void *data)
 static void domain_suspend_callback_common_done(libxl__egc *egc,
                                 libxl__domain_suspend_state *dss, int rc)
 {
+    dss->rc = rc;
     libxl__xc_domain_saverestore_async_callback_done(egc, &dss->shs, !rc);
 }    
 
@@ -1433,6 +1437,7 @@ static void remus_domain_suspend_callback_common_done(libxl__egc *egc,
                                 libxl__domain_suspend_state *dss, int rc)
 {
     /* REMUS TODO: Issue disk and network checkpoint reqs. */
+    dss->rc = rc;
     libxl__xc_domain_saverestore_async_callback_done(egc, &dss->shs, !rc);
 }    
 
@@ -1441,10 +1446,14 @@ static int libxl__remus_domain_resume_callback(void *data)
     libxl__save_helper_state *shs = data;
     libxl__domain_suspend_state *dss = CONTAINER_OF(shs, *dss, shs);
     STATE_AO_GC(dss->ao);
+    int rc;
 
     /* Resumes the domain and the device model */
-    if (libxl__domain_resume(gc, dss->domid, /* Fast Suspend */1))
+    rc = libxl__domain_resume(gc, dss->domid, /* Fast Suspend */1);
+    if (rc) {
+        dss->rc = rc;
         return 0;
+    }
 
     /* REMUS TODO: Deal with disk. Start a new network output buffer */
     return 1;
@@ -1498,6 +1507,7 @@ void libxl__domain_suspend(libxl__egc *egc, libxl__domain_suspend_state *dss)
     libxl__srm_save_autogen_callbacks *const callbacks =
         &dss->shs.callbacks.save.a;
 
+    dss->rc = 0;
     logdirty_init(&dss->logdirty);
     libxl__xswait_init(&dss->pvcontrol);
     libxl__ev_evtchn_init(&dss->guest_evtchn);
@@ -1591,6 +1601,8 @@ void libxl__xc_domain_save_done(libxl__egc *egc, void *dss_void,
                          "domain did not respond to suspend request");
         if ( !dss->guest_responded )
             rc = ERROR_GUEST_TIMEDOUT;
+        else if (dss->rc)
+            rc = dss->rc;
         else
             rc = ERROR_FAIL;
         goto out;
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 7c98d5b..1ad2516 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -2404,6 +2404,7 @@ struct libxl__domain_suspend_state {
     int debug;
     const libxl_domain_remus_info *remus;
     /* private */
+    int rc;
     libxl__ev_evtchn guest_evtchn;
     int guest_evtchn_lockfd;
     int hvm;
-- 
1.7.10.4