migration: make *save_live return errors

Make *save_live() return negative values when there is one error, and
updates all callers to check for the error.
Signed-off-by: Juan Quintela <quintela@redhat.com>

arch_init.c

@@ -256,6 +256,7 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
     uint64_t bytes_transferred_last;
     double bwidth = 0;
     uint64_t expected_time = 0;
+    int ret;
 
     if (stage < 0) {
         cpu_physical_memory_set_dirty_tracking(0);
@@ -264,7 +265,7 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
 
     if (cpu_physical_sync_dirty_bitmap(0, TARGET_PHYS_ADDR_MAX) != 0) {
         qemu_file_set_error(f, -EINVAL);
-        return 0;
+        return -EINVAL;
     }
 
     if (stage == 1) {
@@ -300,7 +301,7 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
     bytes_transferred_last = bytes_transferred;
     bwidth = qemu_get_clock_ns(rt_clock);
 
-    while (!qemu_file_rate_limit(f)) {
+    while ((ret = qemu_file_rate_limit(f)) == 0) {
         int bytes_sent;
 
         bytes_sent = ram_save_block(f);
@@ -310,6 +311,10 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
         }
     }
 
+    if (ret < 0) {
+        return ret;
+    }
+
     bwidth = qemu_get_clock_ns(rt_clock) - bwidth;
     bwidth = (bytes_transferred - bytes_transferred_last) / bwidth;
 

block-migration.c

@@ -557,6 +557,8 @@ static void blk_mig_cleanup(Monitor *mon)
 
 static int block_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
 {
+    int ret;
+
     DPRINTF("Enter save live stage %d submitted %d transferred %d\n",
             stage, block_mig_state.submitted, block_mig_state.transferred);
 
@@ -580,9 +582,10 @@ static int block_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
 
     flush_blks(f);
 
-    if (qemu_file_get_error(f)) {
+    ret = qemu_file_get_error(f);
+    if (ret) {
         blk_mig_cleanup(mon);
-        return 0;
+        return ret;
     }
 
     blk_mig_reset_dirty_cursor();
@@ -608,9 +611,10 @@ static int block_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
 
         flush_blks(f);
 
-        if (qemu_file_get_error(f)) {
+        ret = qemu_file_get_error(f);
+        if (ret) {
             blk_mig_cleanup(mon);
-            return 0;
+            return ret;
         }
     }
 
@@ -625,8 +629,9 @@ static int block_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
         /* report completion */
         qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS);
 
-        if (qemu_file_get_error(f)) {
-            return 0;
+        ret = qemu_file_get_error(f);
+        if (ret) {
+            return ret;
         }
 
         monitor_printf(mon, "Block migration completed\n");

savevm.c

@@ -1534,7 +1534,11 @@ int qemu_savevm_state_begin(Monitor *mon, QEMUFile *f, int blk_enable,
         qemu_put_be32(f, se->instance_id);
         qemu_put_be32(f, se->version_id);
 
-        se->save_live_state(mon, f, QEMU_VM_SECTION_START, se->opaque);
+        ret = se->save_live_state(mon, f, QEMU_VM_SECTION_START, se->opaque);
+        if (ret < 0) {
+            qemu_savevm_state_cancel(mon, f);
+            return ret;
+        }
     }
     ret = qemu_file_get_error(f);
     if (ret != 0) {
@@ -1565,7 +1569,7 @@ int qemu_savevm_state_iterate(Monitor *mon, QEMUFile *f)
         qemu_put_be32(f, se->section_id);
 
         ret = se->save_live_state(mon, f, QEMU_VM_SECTION_PART, se->opaque);
-        if (!ret) {
+        if (ret <= 0) {
             /* Do not proceed to the next vmstate before this one reported
                completion of the current stage. This serializes the migration
                and reduces the probability that a faster changing state is
@@ -1586,6 +1590,7 @@ int qemu_savevm_state_iterate(Monitor *mon, QEMUFile *f)
 int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f)
 {
     SaveStateEntry *se;
+    int ret;
 
     cpu_synchronize_all_states();
 
@@ -1597,7 +1602,10 @@ int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f)
         qemu_put_byte(f, QEMU_VM_SECTION_END);
         qemu_put_be32(f, se->section_id);
 
-        se->save_live_state(mon, f, QEMU_VM_SECTION_END, se->opaque);
+        ret = se->save_live_state(mon, f, QEMU_VM_SECTION_END, se->opaque);
+        if (ret < 0) {
+            return ret;
+        }
     }
 
     QTAILQ_FOREACH(se, &savevm_handlers, entry) {