migration: disallow migrate_add_blocker during migration

If a migration is already in progress and somebody attempts
to add a migration blocker, this should rightly fail.

Add an errp parameter and a retcode return value to migrate_add_blocker.

Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Message-Id: <1484566314-3987-5-git-send-email-ashijeetacharya@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  Merged with recent 'Allow invtsc migration' change
This commit is contained in:
Ashijeet Acharya 2017-01-16 17:01:53 +05:30 committed by Dr. David Alan Gilbert
parent a3a3d8c738
commit fe44dc9180
18 changed files with 222 additions and 81 deletions

View file

@ -979,6 +979,7 @@ static void coroutine_fn v9fs_attach(void *opaque)
size_t offset = 7;
V9fsQID qid;
ssize_t err;
Error *local_err = NULL;
v9fs_string_init(&uname);
v9fs_string_init(&aname);
@ -1007,26 +1008,36 @@ static void coroutine_fn v9fs_attach(void *opaque)
clunk_fid(s, fid);
goto out;
}
/*
* disable migration if we haven't done already.
* attach could get called multiple times for the same export.
*/
if (!s->migration_blocker) {
error_setg(&s->migration_blocker,
"Migration is disabled when VirtFS export path '%s' is mounted in the guest using mount_tag '%s'",
s->ctx.fs_root ? s->ctx.fs_root : "NULL", s->tag);
err = migrate_add_blocker(s->migration_blocker, &local_err);
if (local_err) {
error_free(local_err);
error_free(s->migration_blocker);
s->migration_blocker = NULL;
clunk_fid(s, fid);
goto out;
}
s->root_fid = fid;
}
err = pdu_marshal(pdu, offset, "Q", &qid);
if (err < 0) {
clunk_fid(s, fid);
goto out;
}
err += offset;
memcpy(&s->root_qid, &qid, sizeof(qid));
trace_v9fs_attach_return(pdu->tag, pdu->id,
qid.type, qid.version, qid.path);
/*
* disable migration if we haven't done already.
* attach could get called multiple times for the same export.
*/
if (!s->migration_blocker) {
s->root_fid = fid;
error_setg(&s->migration_blocker,
"Migration is disabled when VirtFS export path '%s' is mounted in the guest using mount_tag '%s'",
s->ctx.fs_root ? s->ctx.fs_root : "NULL", s->tag);
migrate_add_blocker(s->migration_blocker);
}
out:
put_fid(pdu, fidp);
out_nofid: