[Qemu-devel] [PATCH] migration: Fix block failure cases

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

This fixes a couple of cases where the block migration capability
doesn't get cleared when a migration failed.

1) When block migration is compiled out:
  (qemu) migrate -d -b  "exec:cat > /dev/null"
  QEMU compiled without old-style (blk/-b, inc/-i) block migration
  Use drive_mirror+NBD instead.
  (qemu) migrate_set_capability xbzrle off
  QEMU compiled without old-style (blk/-b, inc/-i) block migration
  Use drive_mirror+NBD instead.

  This corresponds to https://bugzilla.redhat.com/show_bug.cgi?id=1550022

2) When a migration with a bad protocol is tried:
  (qemu) migrate -d -b "foo:bah"
  Parameter 'uri' expects a valid migration protocol
  (qemu) info migrate_capabilities
  xbzrle: off
  rdma-pin-all: off
  auto-converge: off
  zero-blocks: off
  compress: off
  events: off
  postcopy-ram: off
  x-colo: off
  release-ram: off
  block: on   <<<<<<-----
  return-path: off
  pause-before-switchover: off
  x-multifd: off

Fixes: 2833c59b947
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/migration.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index b913b98803..da0e4a1f56 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1391,11 +1391,12 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
             return;
         }
         migrate_set_block_enabled(true, &local_err);
+        s->must_remove_block_options = true;
         if (local_err) {
             error_propagate(errp, local_err);
+            block_cleanup_parameters(s);
             return;
         }
-        s->must_remove_block_options = true;
     }
 
     if (has_inc && inc) {
@@ -1417,11 +1418,10 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
     } else if (strstart(uri, "fd:", &p)) {
         fd_start_outgoing_migration(s, p, &local_err);
     } else {
-        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
+        error_setg(&local_err, QERR_INVALID_PARAMETER_VALUE, "uri",
                    "a valid migration protocol");
         migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
                           MIGRATION_STATUS_FAILED);
-        return;
     }
 
     if (local_err) {
-- 
2.14.3