Extend the blocker interface so that a blocker can be registered for
one or more migration modes. The existing interfaces register a
blocker for all modes, and the new interfaces take a varargs list
of modes.
Internally, maintain a separate blocker list per mode. The same Error
object may be added to multiple lists. When a block is deleted, it is
removed from every list, and the Error is freed.
No functional change until a new mode is added.
Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
---
include/migration/blocker.h | 45 ++++++++++++++++++++---
migration/migration.c | 87 +++++++++++++++++++++++++++++++++++++++------
stubs/migr-blocker.c | 5 +++
3 files changed, 123 insertions(+), 14 deletions(-)
diff --git a/include/migration/blocker.h b/include/migration/blocker.h
index 1483f5d..1a21937 100644
--- a/include/migration/blocker.h
+++ b/include/migration/blocker.h
@@ -14,8 +14,12 @@
#ifndef MIGRATION_BLOCKER_H
#define MIGRATION_BLOCKER_H
+#include "qapi/qapi-types-migration.h"
+
+#define MIG_MODE_ALL MIG_MODE__MAX
+
/**
- * @migrate_add_blocker - prevent migration from proceeding
+ * @migrate_add_blocker - prevent all modes of migration from proceeding
*
* @reasonp - address of an error to be returned whenever migration is
attempted
*
@@ -29,8 +33,41 @@
int migrate_add_blocker(Error **reasonp, Error **errp);
/**
+ * @migrate_add_blockers - prevent migration for specified modes from
proceeding
+ *
+ * @reasonp - address of an error to be returned whenever migration is
attempted
+ *
+ * @errp - [out] The reason (if any) we cannot block migration right now.
+ *
+ * @mode - one or more migration modes to be blocked. The list is terminated
+ * by -1 or MIG_MODE_ALL. For the latter, all modes are blocked.
+ *
+ * @returns - 0 on success, -EBUSY/-EACCES on failure, with errp set.
+ *
+ * *@reasonp is freed and set to NULL if failure is returned.
+ * On success, the caller must not free *@reasonp before the blocker is
removed.
+ */
+int migrate_add_blockers(Error **reasonp, Error **errp, MigMode mode, ...);
+
+/**
+ * @migrate_add_blocker_always - permanently prevent migration for specified
+ * modes from proceeding. The blocker cannot be deleted.
+ *
+ * @msg - text of error to be returned whenever migration is attempted
+ *
+ * @errp - [out] The reason (if any) we cannot block migration right now.
+ *
+ * @mode - one or more migration modes to be blocked. The list is terminated
+ * by -1 or MIG_MODE_ALL. For the latter, all modes are blocked.
+ *
+ * @returns - 0 on success, -EBUSY/-EACCES on failure, with errp set.
+ */
+int
+migrate_add_blocker_always(const char *msg, Error **errp, MigMode mode, ...);
+
+/**
* @migrate_add_blocker_internal - prevent migration from proceeding without
- * only-migrate implications
+ * only-migrate implications, for all modes
*
* @reasonp - address of an error to be returned whenever migration is
attempted
*
@@ -48,7 +85,7 @@ int migrate_add_blocker(Error **reasonp, Error **errp);
int migrate_add_blocker_internal(Error **reasonp, Error **errp);
/**
- * @migrate_del_blocker - remove a blocking error from migration and free it.
+ * @migrate_del_blocker - remove a migration blocker for all modes and free it.
*
* @reasonp - address of the error blocking migration
*
@@ -57,7 +94,7 @@ int migrate_add_blocker_internal(Error **reasonp, Error
**errp);
void migrate_del_blocker(Error **reasonp);
/**
- * @migrate_remove_blocker - remove a migration blocker.
+ * @migrate_remove_blocker - remove a migration blocker for all modes.
*
* @reason - the error blocking migration
*
diff --git a/migration/migration.c b/migration/migration.c
index 0d3bed5..0e62227 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -175,7 +175,7 @@ static MigrationState *current_migration;
static MigrationIncomingState *current_incoming;
static int migrate_enabled_modes = BIT(MIG_MODE_NORMAL);
-static GSList *migration_blockers;
+static GSList *migration_blockers[MIG_MODE__MAX];
static bool migration_object_check(MigrationState *ms, Error **errp);
static int migration_maybe_pause(MigrationState *s,
@@ -1123,7 +1123,7 @@ static void fill_source_migration_info(MigrationInfo
*info)
{
MigrationState *s = migrate_get_current();
int state = qatomic_read(&s->state);
- GSList *cur_blocker = migration_blockers;
+ GSList *cur_blocker = migration_blockers[migrate_mode()];
info->blocked_reasons = NULL;
@@ -2198,8 +2198,10 @@ void migrate_init(MigrationState *s)
s->threshold_size = 0;
}
-int migrate_add_blocker_internal(Error **reasonp, Error **errp)
+static int add_blockers(Error **reasonp, Error **errp, int modes)
{
+ MigMode mode;
+
/* Snapshots are similar to migrations, so check RUN_STATE_SAVE_VM too. */
if (runstate_check(RUN_STATE_SAVE_VM) || !migration_is_idle()) {
error_propagate_prepend(errp, *reasonp,
@@ -2209,13 +2211,20 @@ int migrate_add_blocker_internal(Error **reasonp, Error
**errp)
return -EBUSY;
}
- migration_blockers = g_slist_prepend(migration_blockers, *reasonp);
+ for (mode = 0; mode < MIG_MODE__MAX; mode++) {
+ if (modes & BIT(mode)) {
+ migration_blockers[mode] =
g_slist_prepend(migration_blockers[mode],
+ *reasonp);
+ }
+ }
return 0;
}
-int migrate_add_blocker(Error **reasonp, Error **errp)
+static int check_blockers(Error **reasonp, Error **errp, int modes)
{
- if (only_migratable) {
+ ERRP_GUARD();
+
+ if (only_migratable && (modes & BIT(MIG_MODE_NORMAL))) {
error_propagate_prepend(errp, *reasonp,
"disallowing migration blocker "
"(--only-migratable) for: ");
@@ -2223,7 +2232,60 @@ int migrate_add_blocker(Error **reasonp, Error **errp)
return -EACCES;
}
- return migrate_add_blocker_internal(reasonp, errp);
+ return add_blockers(reasonp, errp, modes);
+}
+
+int migrate_add_blocker(Error **reasonp, Error **errp)
+{
+ return migrate_add_blockers(reasonp, errp, MIG_MODE_ALL);
+}
+
+int migrate_add_blocker_internal(Error **reasonp, Error **errp)
+{
+ int modes = BIT(MIG_MODE__MAX) - 1;
+
+ return add_blockers(reasonp, errp, modes);
+}
+
+static int get_modes(MigMode mode, va_list ap)
+{
+ int modes = 0;
+
+ while (mode != -1 && mode != MIG_MODE_ALL) {
+ assert(mode >= MIG_MODE_NORMAL && mode < MIG_MODE__MAX);
+ modes |= BIT(mode);
+ mode = va_arg(ap, MigMode);
+ }
+ if (mode == MIG_MODE_ALL) {
+ modes = BIT(MIG_MODE__MAX) - 1;
+ }
+ return modes;
+}
+
+int migrate_add_blockers(Error **reasonp, Error **errp, MigMode mode, ...)
+{
+ int modes;
+ va_list ap;
+
+ va_start(ap, mode);
+ modes = get_modes(mode, ap);
+ va_end(ap);
+
+ return check_blockers(reasonp, errp, modes);
+}
+
+int migrate_add_blocker_always(const char *msg, Error **errp, MigMode mode,
...)
+{
+ int modes;
+ va_list ap;
+ Error *reason = NULL;
+
+ va_start(ap, mode);
+ modes = get_modes(mode, ap);
+ va_end(ap);
+
+ error_setg(&reason, "%s", msg);
+ return check_blockers(&reason, errp, modes);
}
void migrate_del_blocker(Error **reasonp)
@@ -2238,7 +2300,10 @@ void migrate_del_blocker(Error **reasonp)
void migrate_remove_blocker(Error *reason)
{
if (reason) {
- migration_blockers = g_slist_remove(migration_blockers, reason);
+ for (MigMode mode = 0; mode < MIG_MODE__MAX; mode++) {
+ migration_blockers[mode] = g_slist_remove(migration_blockers[mode],
+ reason);
+ }
}
}
@@ -2333,12 +2398,14 @@ void qmp_migrate_pause(Error **errp)
bool migration_is_blocked(Error **errp)
{
+ GSList *blockers = migration_blockers[migrate_mode()];
+
if (qemu_savevm_state_blocked(errp)) {
return true;
}
- if (migration_blockers) {
- error_propagate(errp, error_copy(migration_blockers->data));
+ if (blockers) {
+ error_propagate(errp, error_copy(blockers->data));
return true;
}
diff --git a/stubs/migr-blocker.c b/stubs/migr-blocker.c
index 17a5dbf..60769d8 100644
--- a/stubs/migr-blocker.c
+++ b/stubs/migr-blocker.c
@@ -6,6 +6,11 @@ int migrate_add_blocker(Error **reasonp, Error **errp)
return 0;
}
+int migrate_add_blockers(Error **reasonp, Error **errp, MigMode mode, ...)
+{
+ return 0;
+}
+
void migrate_del_blocker(Error **reasonp)
{
}
--
1.8.3.1
