[PATCH RFC v3 RESEND 11/12] Migration with Local Disks Mirroring: libxl write stream support for stream phase type

[Bruno Alvisio <bruno.alvisio@gmail.com>]

The libxl stream write receives stream phase type (DEFAULT, PRE_MIRROR_DISKS or
POST_MIRROR_DISKS) and registers the appropiate callback to the
libxl_save_helper. If the stream phase == PRE_MIRROR_DISKS the stream skips
writing the context record since it is written at a later time by the
POST_MIRROR_DISKS libxl stream.

Signed-off-by: Bruno Alvisio <bruno.alvisio@gmail.com>
---
 tools/libxc/include/xenguest.h   |  3 +-
 tools/libxc/xc_nomigrate.c       |  3 +-
 tools/libxc/xc_sr_save.c         |  3 +-
 tools/libxl/libxl_internal.h     | 12 +++++--
 tools/libxl/libxl_save_callout.c | 10 ++++--
 tools/libxl/libxl_save_helper.c  |  3 +-
 tools/libxl/libxl_stream_write.c | 67 +++++++++++++++++++++++++++++-----------
 7 files changed, 73 insertions(+), 28 deletions(-)

diff --git a/tools/libxc/include/xenguest.h b/tools/libxc/include/xenguest.h
index 014dee0..743294b 100644
--- a/tools/libxc/include/xenguest.h
+++ b/tools/libxc/include/xenguest.h
@@ -134,7 +134,8 @@ typedef enum {
 int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom,
                    uint32_t flags /* XCFLAGS_xxx */,
                    struct save_callbacks* callbacks, int hvm,
-                   xc_migration_stream_t stream_type, int recv_fd);
+                   xc_migration_stream_t stream_type, int recv_fd,
+                   int stream_phase);
 
 /* callbacks provided by xc_domain_restore */
 struct restore_callbacks {
diff --git a/tools/libxc/xc_nomigrate.c b/tools/libxc/xc_nomigrate.c
index 75fe560..ab2d744 100644
--- a/tools/libxc/xc_nomigrate.c
+++ b/tools/libxc/xc_nomigrate.c
@@ -22,7 +22,8 @@
 
 int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t flags,
                    struct save_callbacks* callbacks, int hvm,
-                   xc_migration_stream_t stream_type, int recv_fd)
+                   xc_migration_stream_t stream_type, int recv_fd,
+                   int stream_phase)
 {
     errno = ENOSYS;
     return -1;
diff --git a/tools/libxc/xc_sr_save.c b/tools/libxc/xc_sr_save.c
index 5a40e58..b7498e3 100644
--- a/tools/libxc/xc_sr_save.c
+++ b/tools/libxc/xc_sr_save.c
@@ -967,7 +967,8 @@ static int save(struct xc_sr_context *ctx, uint16_t guest_type)
 
 int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom,
                    uint32_t flags, struct save_callbacks* callbacks,
-                   int hvm, xc_migration_stream_t stream_type, int recv_fd)
+                   int hvm, xc_migration_stream_t stream_type, int recv_fd,
+                   int stream_phase)
 {
     struct xc_sr_context ctx =
         {
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 0a3215f..320c97d 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -3799,12 +3799,18 @@ _hidden void libxl__domain_save(libxl__egc *egc,
 /* calls libxl__xc_domain_suspend_done when done */
 _hidden void libxl__xc_domain_save(libxl__egc *egc,
                                    libxl__domain_save_state *dss,
-                                   libxl__save_helper_state *shs);
+                                   libxl__save_helper_state *shs,
+                                   int stream_phase);
 /* If rc==0 then retval is the return value from xc_domain_save
  * and errnoval is the errno value it provided.
  * If rc!=0, retval and errnoval are undefined. */
-_hidden void libxl__xc_domain_save_done(libxl__egc*, void *dss_void,
-                                        int rc, int retval, int errnoval);
+_hidden void libxl__xc_domain_save_returned(libxl__egc*, void *dss_void,
+                                            int rc, int retval, int errnoval);
+
+_hidden void libxl__xc_mirror_disks_save_returned(libxl__egc *egc,
+                                                  void *dss_void,
+                                                  int rc, int retval,
+                                                  int errnoval);
 
 /* Used by asynchronous callbacks: ie ones which xc regards as
  * returning a value, but which we want to handle asynchronously.
diff --git a/tools/libxl/libxl_save_callout.c b/tools/libxl/libxl_save_callout.c
index 0ff9a01..090d50b 100644
--- a/tools/libxl/libxl_save_callout.c
+++ b/tools/libxl/libxl_save_callout.c
@@ -86,7 +86,7 @@ void libxl__xc_domain_restore(libxl__egc *egc, libxl__domain_create_state *dcs,
 }
 
 void libxl__xc_domain_save(libxl__egc *egc, libxl__domain_save_state *dss,
-                           libxl__save_helper_state *shs)
+                           libxl__save_helper_state *shs, int stream_phase)
 {
     STATE_AO_GC(dss->ao);
 
@@ -95,13 +95,17 @@ void libxl__xc_domain_save(libxl__egc *egc, libxl__domain_save_state *dss,
 
     const unsigned long argnums[] = {
         dss->domid, dss->xcflags, dss->hvm, cbflags,
-        dss->checkpointed_stream,
+        dss->checkpointed_stream, stream_phase,
     };
 
     shs->ao = ao;
     shs->domid = dss->domid;
     shs->recv_callback = libxl__srm_callout_received_save;
-    shs->completion_callback = libxl__xc_domain_save_done;
+    if ( stream_phase != LIBXL_STREAM_PHASE_PRE_MIRROR_DISKS )
+        shs->completion_callback = libxl__xc_domain_save_returned;
+    else
+        shs->completion_callback = libxl__xc_mirror_disks_save_returned;
+
     shs->caller_state = dss;
     shs->need_results = 0;
 
diff --git a/tools/libxl/libxl_save_helper.c b/tools/libxl/libxl_save_helper.c
index f1e8dca..53b4d78 100644
--- a/tools/libxl/libxl_save_helper.c
+++ b/tools/libxl/libxl_save_helper.c
@@ -255,6 +255,7 @@ int main(int argc, char **argv)
         int hvm =                           atoi(NEXTARG);
         unsigned cbflags =                  strtoul(NEXTARG,0,10);
         xc_migration_stream_t stream_type = strtoul(NEXTARG,0,10);
+        int stream_phase =                  atoi(NEXTARG);
         assert(!*++argv);
 
         helper_setcallbacks_save(&helper_save_callbacks, cbflags);
@@ -263,7 +264,7 @@ int main(int argc, char **argv)
         setup_signals(save_signal_handler);
 
         r = xc_domain_save(xch, io_fd, dom, flags, &helper_save_callbacks,
-                           hvm, stream_type, recv_fd);
+                           hvm, stream_type, recv_fd, stream_phase);
         complete(r);
 
     } else if (!strcmp(mode,"--restore-domain")) {
diff --git a/tools/libxl/libxl_stream_write.c b/tools/libxl/libxl_stream_write.c
index 634f324..0ff096a 100644
--- a/tools/libxl/libxl_stream_write.c
+++ b/tools/libxl/libxl_stream_write.c
@@ -330,31 +330,43 @@ static void stream_header_done(libxl__egc *egc,
 static void libxc_header_done(libxl__egc *egc,
                               libxl__stream_write_state *stream)
 {
-    libxl__xc_domain_save(egc, stream->dss, &stream->shs);
+    int save_mirror_disks = stream->dss->mirror_disks;
+    libxl__xc_domain_save(egc, stream->dss, &stream->shs,
+                          save_mirror_disks + stream->mirror_disks);
 }
 
-void libxl__xc_domain_save_done(libxl__egc *egc, void *dss_void,
-                                int rc, int retval, int errnoval)
+static void libxl__xc_domain_save_done(libxl__egc *egc, void *dss_void,
+                                       libxl__stream_write_state *stream,
+                                       int rc, int retval, int errnoval)
 {
     libxl__domain_save_state *dss = dss_void;
-    libxl__stream_write_state *stream = &dss->sws;
     STATE_AO_GC(dss->ao);
 
     if (rc)
         goto err;
 
     if (retval) {
-        LOGEVD(ERROR, errnoval, dss->domid, "saving domain: %s",
-              dss->dsps.guest_responded ?
-              "domain responded to suspend request" :
-              "domain did not respond to suspend request");
-        if (!dss->dsps.guest_responded)
-            rc = ERROR_GUEST_TIMEDOUT;
-        else if (dss->rc)
-            rc = dss->rc;
-        else
-            rc = ERROR_FAIL;
-        goto err;
+        if (!stream->mirror_disks) {
+            LOGEVD(ERROR, errnoval, dss->domid, "saving domain: %s",
+                   dss->dsps.guest_responded ?
+                   "domain responded to suspend request" :
+                   "domain did not respond to suspend request");
+            if (!dss->dsps.guest_responded)
+                rc = ERROR_GUEST_TIMEDOUT;
+            else if (dss->rc)
+                rc = dss->rc;
+            else
+                rc = ERROR_FAIL;
+            goto err;
+        } else {
+            LOGEVD(ERROR, errnoval, dss->domid, "saving domain: Error occurred "
+                   "in libxc pre mirror phase stream");
+            if (dss->rc)
+                rc = dss->rc;
+            else
+                rc = ERROR_FAIL;
+            goto err;
+        }
     }
 
  err:
@@ -380,6 +392,22 @@ void libxl__xc_domain_save_done(libxl__egc *egc, void *dss_void,
     }
 }
 
+void libxl__xc_mirror_disks_save_returned(libxl__egc *egc, void *dss_void,
+                                          int rc, int retval, int errnoval)
+{
+    libxl__domain_save_state *dss = dss_void;
+    libxl__stream_write_state *stream = &dss->sws_mirror_disks;
+    libxl__xc_domain_save_done(egc, dss_void, stream, rc, retval, errnoval);
+}
+
+void libxl__xc_domain_save_returned(libxl__egc *egc, void *dss_void,
+                                    int rc, int retval, int errnoval)
+{
+    libxl__domain_save_state *dss = dss_void;
+    libxl__stream_write_state *stream = &dss->sws;
+    libxl__xc_domain_save_done(egc, dss_void, stream, rc, retval, errnoval);
+}
+
 static void write_emulator_xenstore_record(libxl__egc *egc,
                                            libxl__stream_write_state *stream)
 {
@@ -424,9 +452,12 @@ static void emulator_xenstore_record_done(libxl__egc *egc,
 {
     libxl__domain_save_state *dss = stream->dss;
 
-    if (dss->type == LIBXL_DOMAIN_TYPE_HVM)
-        write_emulator_context_record(egc, stream);
-    else {
+    if (dss->type == LIBXL_DOMAIN_TYPE_HVM) {
+        if (!stream->mirror_disks)
+            write_emulator_context_record(egc, stream);
+        else
+            write_end_record(egc, stream);
+    } else {
         if (stream->in_checkpoint)
             write_checkpoint_end_record(egc, stream);
         else
-- 
2.3.2 (Apple Git-55)


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