It was allowed in the past to even cancel a postcopy migration, but it
does not really make sense, and no one should be using it, since
cancelling a migration during postcopy means crashing the VM at no time.
Let's just use re-use this command as a way to pause the postcopy
migration when we detected that we are in postcopy migration. This can
be used when we want to trigger the postcopy recovery manually.
Signed-off-by: Peter Xu <pet...@redhat.com>
---
hmp-commands.hx | 8 ++++++--
migration/migration.c | 18 +++++++++++++++++-
qapi/migration.json | 3 ++-
3 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/hmp-commands.hx b/hmp-commands.hx
index ffcdc34652..32fdd52212 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -952,14 +952,18 @@ ETEXI
.name = "migrate_cancel",
.args_type = "",
.params = "",
- .help = "cancel the current VM migration",
+ .help = "cancel the current VM precopy migration, or "
+ "pause the migration if it's in postcopy state, "
+ "so that a postcopy recovery can be carried out later.",
.cmd = hmp_migrate_cancel,
},
STEXI
@item migrate_cancel
@findex migrate_cancel
-Cancel the current VM migration.
+If during a precopy, this command cancels the migration. If during
+postcopy, this command pauses the migration (so that a postcopy
+recovery can be carried out afterward).
ETEXI
{
diff --git a/migration/migration.c b/migration/migration.c
index 8762fad9be..0c1a783df2 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1535,7 +1535,23 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
void qmp_migrate_cancel(Error **errp)
{
- migrate_fd_cancel(migrate_get_current());
+ MigrationState *ms = migrate_get_current();
+ int ret;
+
+ if (ms->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
+ /*
+ * Cancelling a postcopy migration does not really make sense.
+ * Here instead we pause the migration only, so another
+ * recovery can take place if needed.
+ */
+ ret = qemu_file_shutdown(ms->to_dst_file);
+ if (ret) {
+ error_setg(errp, "Failed to pause migration stream.");
+ }
+ return;
+ }
+
+ migrate_fd_cancel(ms);
}
void qmp_migrate_continue(MigrationStatus state, Error **errp)
diff --git a/qapi/migration.json b/qapi/migration.json
index 5dfac0681d..e15bb516cd 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -881,7 +881,8 @@
##
# @migrate_cancel:
#
-# Cancel the current executing migration process.
+# Cancel the current executing migration process for precopy. For
+# postcopy, it'll pause the migration instead.
#
# Returns: nothing on success
#
--
2.14.3
