[Qemu-stable] [PATCH 34/56] cpus: Let vm_stop[_force_state]() always flush block devices

[Michael Roth]

From: Kevin Wolf <address@hidden>

Even if the VM is already stopped, we cannot assume that all data has
already been successfully flushed to disk. The flush during the previous
vm_stop() could have failed.

Run bdrv_flush_all() unconditionally so that we get an error each time
if the block device isn't really flushed.

Signed-off-by: Kevin Wolf <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
(cherry picked from commit 594a45ce64dbef1829996403506a1154eb2fd1cc)

Signed-off-by: Michael Roth <address@hidden>
---
 cpus.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/cpus.c b/cpus.c
index 2a2f633..65b0b0e 100644
--- a/cpus.c
+++ b/cpus.c
@@ -446,11 +446,12 @@ static int do_vm_stop(RunState state)
         pause_all_vcpus();
         runstate_set(state);
         vm_state_notify(0, state);
-        bdrv_drain_all();
-        ret = bdrv_flush_all();
         monitor_protocol_event(QEVENT_STOP, NULL);
     }
 
+    bdrv_drain_all();
+    ret = bdrv_flush_all();
+
     return ret;
 }
 
@@ -1120,7 +1121,9 @@ int vm_stop_force_state(RunState state)
         return vm_stop(state);
     } else {
         runstate_set(state);
-        return 0;
+        /* Make sure to return an error if the flush in a previous vm_stop()
+         * failed. */
+        return bdrv_flush_all();
     }
 }
 
-- 
1.7.9.5