Commit 62df066f authored by Peter Xu's avatar Peter Xu Committed by Juan Quintela
Browse files

migration: introduce lock for to_dst_file 



Let's introduce a lock for that QEMUFile since we are going to operate
on it in multiple threads.

Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-23-peterx@redhat.com>
Signed-off-by: default avatarJuan Quintela <quintela@redhat.com>
parent 3b563c4b

migration/channel.c

+2 −1
Original line number Diff line number Diff line
@@ -74,8 +74,9 @@ void migration_channel_connect(MigrationState *s, 
        } else {

            QEMUFile *f = qemu_fopen_channel_output(ioc);



            qemu_mutex_lock(&s->qemu_file_lock);

            s->to_dst_file = f;



            qemu_mutex_unlock(&s->qemu_file_lock);

        }

    }

    migrate_fd_connect(s, error);

migration/migration.c

+19 −3
Original line number Diff line number Diff line
@@ -1234,6 +1234,7 @@ static void migrate_fd_cleanup(void *opaque) 


    if (s->to_dst_file) {

        Error *local_err = NULL;

        QEMUFile *tmp;



        trace_migrate_fd_cleanup();

        qemu_mutex_unlock_iothread();
@@ -1246,8 +1247,15 @@ static void migrate_fd_cleanup(void *opaque) 
        if (multifd_save_cleanup(&local_err) != 0) {

            error_report_err(local_err);

        }

        qemu_fclose(s->to_dst_file);

        qemu_mutex_lock(&s->qemu_file_lock);

        tmp = s->to_dst_file;

        s->to_dst_file = NULL;

        qemu_mutex_unlock(&s->qemu_file_lock);

        /*

         * Close the file handle without the lock to make sure the

         * critical section won't block for long.

         */

        qemu_fclose(tmp);

    }



    assert((s->state != MIGRATION_STATUS_ACTIVE) &&
@@ -2531,14 +2539,20 @@ static MigThrError postcopy_pause(MigrationState *s) 
    assert(s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE);



    while (true) {

        QEMUFile *file;



        migrate_set_state(&s->state, s->state,

                          MIGRATION_STATUS_POSTCOPY_PAUSED);



        /* Current channel is possibly broken. Release it. */

        assert(s->to_dst_file);

        qemu_file_shutdown(s->to_dst_file);

        qemu_fclose(s->to_dst_file);

        qemu_mutex_lock(&s->qemu_file_lock);

        file = s->to_dst_file;

        s->to_dst_file = NULL;

        qemu_mutex_unlock(&s->qemu_file_lock);



        qemu_file_shutdown(file);

        qemu_fclose(file);



        error_report("Detected IO failure for postcopy. "

                     "Migration paused.");
@@ -3007,6 +3021,7 @@ static void migration_instance_finalize(Object *obj) 
    MigrationParameters *params = &ms->parameters;



    qemu_mutex_destroy(&ms->error_mutex);

    qemu_mutex_destroy(&ms->qemu_file_lock);

    g_free(params->tls_hostname);

    g_free(params->tls_creds);

    qemu_sem_destroy(&ms->pause_sem);
@@ -3046,6 +3061,7 @@ static void migration_instance_init(Object *obj) 
    qemu_sem_init(&ms->postcopy_pause_sem, 0);

    qemu_sem_init(&ms->postcopy_pause_rp_sem, 0);

    qemu_sem_init(&ms->rp_state.rp_sem, 0);

    qemu_mutex_init(&ms->qemu_file_lock);

}



/*

migration/migration.h

+6 −0
Original line number Diff line number Diff line
@@ -114,6 +114,12 @@ struct MigrationState 
    QemuThread thread;

    QEMUBH *cleanup_bh;

    QEMUFile *to_dst_file;

    /*

     * Protects to_dst_file pointer.  We need to make sure we won't

     * yield or hang during the critical section, since this lock will

     * be used in OOB command handler.

     */

    QemuMutex qemu_file_lock;



    /* bytes already send at the beggining of current interation */

    uint64_t iteration_initial_bytes;