Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging

Block pull request

# gpg: Signature made Mon 23 Jun 2014 09:53:49 BST using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

* remotes/stefanha/tags/block-pull-request:
  block: asynchronously stop the VM on I/O errors
  vl: allow other threads to do qemu_system_vmstop_request
  sheepdog: fix NULL dereference in sd_create
  QemuOpts: check NULL opts in qemu_opt_get functions
  block: m25p80: Support read only bdrvs.
  block: m25p80: sync_page(): Deindent function body.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 19 insertions, 2 deletions

diff --git a/block.c b/block.c
index 43abe96db6..ff44e76c87 100644
--- a/block.c
+++ b/block.c
@@ -3626,10 +3626,27 @@ void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action,
                        bool is_read, int error)
 {
     assert(error >= 0);
-    bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read);
+
     if (action == BDRV_ACTION_STOP) {
-        vm_stop(RUN_STATE_IO_ERROR);
+        /* First set the iostatus, so that "info block" returns an iostatus
+         * that matches the events raised so far (an additional error iostatus
+         * is fine, but not a lost one).
+         */
         bdrv_iostatus_set_err(bs, error);
+
+        /* Then raise the request to stop the VM and the event.
+         * qemu_system_vmstop_request_prepare has two effects.  First,
+         * it ensures that the STOP event always comes after the
+         * BLOCK_IO_ERROR event.  Second, it ensures that even if management
+         * can observe the STOP event and do a "cont" before the STOP
+         * event is issued, the VM will not stop.  In this case, vm_start()
+         * also ensures that the STOP/RESUME pair of events is emitted.
+         */
+        qemu_system_vmstop_request_prepare();
+        bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read);
+        qemu_system_vmstop_request(RUN_STATE_IO_ERROR);
+    } else {
+        bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read);
     }
 }