Commit aef06085 authored by zhanghailiang's avatar zhanghailiang Committed by Amit Shah
Browse files

COLO: Introduce state to record failover process 



When handling failover, COLO processes differently according to
the different stage of failover process, here we introduce a global
atomic variable to record the status of failover.

We add four failover status to indicate the different stage of failover process.
You should use the helpers to get and set the value.

Signed-off-by: default avatarzhanghailiang <zhang.zhanghailiang@huawei.com>
Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarAmit Shah <amit@amitshah.net>
parent d89e666e

include/migration/failover.h

+5 −0
Original line number Diff line number Diff line
@@ -14,7 +14,12 @@ 
#define QEMU_FAILOVER_H



#include "qemu-common.h"

#include "qapi-types.h"



void failover_init_state(void);

FailoverStatus failover_set_state(FailoverStatus old_state,

                                     FailoverStatus new_state);

FailoverStatus failover_get_state(void);

void failover_request_active(Error **errp);



#endif

migration/colo-failover.c

+41 −0
Original line number Diff line number Diff line
@@ -15,22 +15,63 @@ 
#include "migration/failover.h"

#include "qmp-commands.h"

#include "qapi/qmp/qerror.h"

#include "qemu/error-report.h"

#include "trace.h"



static QEMUBH *failover_bh;

static FailoverStatus failover_state;



static void colo_failover_bh(void *opaque)

{

    int old_state;



    qemu_bh_delete(failover_bh);

    failover_bh = NULL;



    old_state = failover_set_state(FAILOVER_STATUS_REQUIRE,

                                   FAILOVER_STATUS_ACTIVE);

    if (old_state != FAILOVER_STATUS_REQUIRE) {

        error_report("Unknown error for failover, old_state = %s",

                    FailoverStatus_lookup[old_state]);

        return;

    }



    /* TODO: Do failover work */

}



void failover_request_active(Error **errp)

{

   if (failover_set_state(FAILOVER_STATUS_NONE,

        FAILOVER_STATUS_REQUIRE) != FAILOVER_STATUS_NONE) {

        error_setg(errp, "COLO failover is already actived");

        return;

    }

    failover_bh = qemu_bh_new(colo_failover_bh, NULL);

    qemu_bh_schedule(failover_bh);

}



void failover_init_state(void)

{

    failover_state = FAILOVER_STATUS_NONE;

}



FailoverStatus failover_set_state(FailoverStatus old_state,

                    FailoverStatus new_state)

{

    FailoverStatus old;



    old = atomic_cmpxchg(&failover_state, old_state, new_state);

    if (old == old_state) {

        trace_colo_failover_set_state(FailoverStatus_lookup[new_state]);

    }

    return old;

}



FailoverStatus failover_get_state(void)

{

    return atomic_read(&failover_state);

}



void qmp_x_colo_lost_heartbeat(Error **errp)

{

    if (get_colo_mode() == COLO_MODE_UNKNOWN) {

migration/colo.c

+4 −0
Original line number Diff line number Diff line
@@ -232,6 +232,8 @@ static void colo_process_checkpoint(MigrationState *s) 
    Error *local_err = NULL;

    int ret;



    failover_init_state();



    s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file);

    if (!s->rp_state.from_dst_file) {

        error_report("Open QEMUFile from_dst_file failed");
@@ -332,6 +334,8 @@ void *colo_process_incoming_thread(void *opaque) 
    migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,

                      MIGRATION_STATUS_COLO);



    failover_init_state();



    mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);

    if (!mis->to_src_file) {

        error_report("COLO incoming thread: Open QEMUFile to_src_file failed");

migration/trace-events

+1 −0
Original line number Diff line number Diff line
@@ -212,3 +212,4 @@ migration_tls_incoming_handshake_complete(void) "" 
colo_vm_state_change(const char *old, const char *new) "Change '%s' => '%s'"

colo_send_message(const char *msg) "Send '%s' message"

colo_receive_message(const char *msg) "Receive '%s' message"

colo_failover_set_state(const char *new_state) "new state %s"

qapi-schema.json

+18 −0
Original line number Diff line number Diff line
@@ -839,6 +839,24 @@ 
{ 'enum': 'COLOMode',

  'data': [ 'unknown', 'primary', 'secondary'] }



##

# @FailoverStatus

#

# An enumeration of COLO failover status

#

# @none: no failover has ever happened

#

# @require: got failover requirement but not handled

#

# @active: in the process of doing failover

#

# @completed: finish the process of failover

#

# Since: 2.8

##

{ 'enum': 'FailoverStatus',

  'data': [ 'none', 'require', 'active', 'completed'] }



##

# @x-colo-lost-heartbeat

#