[Qemu-devel] [PATCH 15/37] migration: make *save_live return errors

[Juan Quintela]

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 <address@hidden>
---
 arch_init.c       |    9 +++++++--
 block-migration.c |   17 +++++++++++------
 savevm.c          |   14 +++++++++++---
 3 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index 98daaf3..a411fdf 100644
--- a/arch_init.c
+++ b/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;

diff --git a/block-migration.c b/block-migration.c
index b8d19a1..0bff075 100644
--- a/block-migration.c
+++ b/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");
diff --git a/savevm.c b/savevm.c
index f27f474..9a5a369 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1496,7 +1496,11 @@ 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) {
@@ -1527,7 +1531,7 @@ 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
@@ -1548,6 +1552,7 @@ 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();

@@ -1559,7 +1564,10 @@ 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) {
-- 
1.7.6.4