migration/savevm: respect qemu_fclose() error code in save_snapshot()

qemu_fclose() could return error, f.e. if bdrv_co_flush() will return
the error.

This validation will become more important once we will start waiting of
asynchronous IO operations, started from bdrv_write_vmstate(), which are
coming soon.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Fam Zheng <fam@euphon.net>
CC: Juan Quintela <quintela@redhat.com>
CC: Denis Plotnikov <dplotnikov@virtuozzo.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/migration/savevm.c b/migration/savevm.c
index 6e01724605..45c9dd9d8a 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2635,7 +2635,7 @@ int save_snapshot(const char *name, Error **errp)
 {
     BlockDriverState *bs, *bs1;
     QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
-    int ret = -1;
+    int ret = -1, ret2;
     QEMUFile *f;
     int saved_vm_running;
     uint64_t vm_state_size;
@@ -2719,10 +2719,14 @@ int save_snapshot(const char *name, Error **errp)
     }
     ret = qemu_savevm_state(f, errp);
     vm_state_size = qemu_ftell(f);
-    qemu_fclose(f);
+    ret2 = qemu_fclose(f);
     if (ret < 0) {
         goto the_end;
     }
+    if (ret2 < 0) {
+        ret = ret2;
+        goto the_end;
+    }
 
     /* The bdrv_all_create_snapshot() call that follows acquires the AioContext
      * for itself.  BDRV_POLL_WHILE() does not support nested locking because