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: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-23-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Peter Xu 2018-05-02 18:47:38 +08:00 committed by Juan Quintela
parent 3b563c4be0
commit 62df066fff
3 changed files with 27 additions and 4 deletions

View file

@ -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);

View file

@ -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);
}
/*

View file

@ -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;