[10/37] migration: change has_error to contain errno values

diff --git a/arch_init.c b/arch_init.c
index a6c69c7..941d585 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -263,7 +263,7 @@  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);
+        qemu_file_set_error(f, -EINVAL);
         return 0;
     }

diff --git a/block-migration.c b/block-migration.c
index e2775ee..325c905 100644
--- a/block-migration.c
+++ b/block-migration.c
@@ -263,7 +263,7 @@  static int mig_save_device_bulk(Monitor *mon, QEMUFile *f,

 error:
     monitor_printf(mon, "Error reading sector %" PRId64 "\n", cur_sector);
-    qemu_file_set_error(f);
+    qemu_file_set_error(f, -EIO);
     g_free(blk->buf);
     g_free(blk);
     return 0;
@@ -383,6 +383,7 @@  static int mig_save_device_dirty(Monitor *mon, QEMUFile *f,
     int64_t total_sectors = bmds->total_sectors;
     int64_t sector;
     int nr_sectors;
+    int ret = -EIO;

     for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) {
         if (bmds_aio_inflight(bmds, sector)) {
@@ -418,8 +419,8 @@  static int mig_save_device_dirty(Monitor *mon, QEMUFile *f,
                 block_mig_state.submitted++;
                 bmds_set_aio_inflight(bmds, sector, nr_sectors, 1);
             } else {
-                if (bdrv_read(bmds->bs, sector, blk->buf,
-                              nr_sectors) < 0) {
+                ret = bdrv_read(bmds->bs, sector, blk->buf, nr_sectors);
+                if (ret < 0) {
                     goto error;
                 }
                 blk_send(f, blk);
@@ -439,7 +440,7 @@  static int mig_save_device_dirty(Monitor *mon, QEMUFile *f,

 error:
     monitor_printf(mon, "Error reading sector %" PRId64 "\n", sector);
-    qemu_file_set_error(f);
+    qemu_file_set_error(f, ret);
     g_free(blk->buf);
     g_free(blk);
     return 0;
@@ -473,7 +474,7 @@  static void flush_blks(QEMUFile* f)
             break;
         }
         if (blk->ret < 0) {
-            qemu_file_set_error(f);
+            qemu_file_set_error(f, blk->ret);
             break;
         }
         blk_send(f, blk);
diff --git a/buffered_file.c b/buffered_file.c
index 4f49763..94ca8d1 100644
--- a/buffered_file.c
+++ b/buffered_file.c
@@ -92,7 +92,7 @@  static void buffered_flush(QEMUFileBuffered *s)

         if (ret <= 0) {
             DPRINTF("error flushing data, %zd\n", ret);
-            qemu_file_set_error(s->file);
+            qemu_file_set_error(s->file, ret);
             break;
         } else {
             DPRINTF("flushed %zd byte(s)\n", ret);
@@ -138,7 +138,7 @@  static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, in

         if (ret <= 0) {
             DPRINTF("error putting\n");
-            qemu_file_set_error(s->file);
+            qemu_file_set_error(s->file, ret);
             offset = -EINVAL;
             break;
         }
diff --git a/hw/hw.h b/hw/hw.h
index a124da9..6cf8cd2 100644
--- a/hw/hw.h
+++ b/hw/hw.h
@@ -86,7 +86,7 @@  int qemu_file_rate_limit(QEMUFile *f);
 int64_t qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate);
 int64_t qemu_file_get_rate_limit(QEMUFile *f);
 int qemu_file_has_error(QEMUFile *f);
-void qemu_file_set_error(QEMUFile *f);
+void qemu_file_set_error(QEMUFile *f, int error);

 /* Try to send any outstanding data.  This function is useful when output is
  * halted due to rate limiting or EAGAIN errors occur as it can be used to
diff --git a/migration.c b/migration.c
index a682168..d5876a9 100644
--- a/migration.c
+++ b/migration.c
@@ -455,7 +455,7 @@  void migrate_fd_wait_for_unfreeze(void *opaque)
     } while (ret == -1 && (s->get_error(s)) == EINTR);

     if (ret == -1) {
-        qemu_file_set_error(s->file);
+        qemu_file_set_error(s->file, -s->get_error(s));
     }
 }

diff --git a/savevm.c b/savevm.c
index bf4d0e7..8f00f0c 100644
--- a/savevm.c
+++ b/savevm.c
@@ -430,9 +430,9 @@  int qemu_file_has_error(QEMUFile *f)
     return f->has_error;
 }

-void qemu_file_set_error(QEMUFile *f)
+void qemu_file_set_error(QEMUFile *f, int ret)
 {
-    f->has_error = 1;
+    f->has_error = ret;
 }

 void qemu_fflush(QEMUFile *f)
@@ -447,7 +447,7 @@  void qemu_fflush(QEMUFile *f)
         if (len > 0)
             f->buf_offset += f->buf_index;
         else
-            f->has_error = 1;
+            f->has_error = -EINVAL;
         f->buf_index = 0;
     }
 }
@@ -468,7 +468,7 @@  static void qemu_fill_buffer(QEMUFile *f)
         f->buf_size = len;
         f->buf_offset += len;
     } else if (len != -EAGAIN)
-        f->has_error = 1;
+        f->has_error = len;
 }

 int qemu_fclose(QEMUFile *f)