From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37195) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0Sna-0008Qy-3J for qemu-devel@nongnu.org; Wed, 11 May 2016 07:59:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b0SnV-0004ix-Sr for qemu-devel@nongnu.org; Wed, 11 May 2016 07:59:29 -0400 Received: from mail-wm0-x244.google.com ([2a00:1450:400c:c09::244]:34523) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0SnV-0004io-C3 for qemu-devel@nongnu.org; Wed, 11 May 2016 07:59:25 -0400 Received: by mail-wm0-x244.google.com with SMTP id n129so8993710wmn.1 for ; Wed, 11 May 2016 04:59:25 -0700 (PDT) Sender: Paolo Bonzini References: <146239057139.11271.9011797645454781543.stgit@bahia.huguette.org> From: Paolo Bonzini Message-ID: <57331E97.8050205@redhat.com> Date: Wed, 11 May 2016 13:59:19 +0200 MIME-Version: 1.0 In-Reply-To: <146239057139.11271.9011797645454781543.stgit@bahia.huguette.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] migration: introduce migrate_is_blocked() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Greg Kurz , Juan Quintela Cc: Peter Maydell , "Dr. David Alan Gilbert" , qemu-devel@nongnu.org On 04/05/2016 21:44, Greg Kurz wrote: > QEMU has currently two ways to prevent migration to occur: > - migration blocker when it depends on runtime state > - VMStateDescription.unmigratable when migration is not supported at all > > This patch gathers all the logic into a single function to be called from > both the savevm and the migrate paths. > > This fixes a bug with 9p, at least, where savevm would succeed and the > following would happen in the guest after loadvm: > > $ ls /host > ls: cannot access /host: Protocol error > > With this patch: > > (qemu) savevm foo > Migration is disabled when VirtFS export path '/' is mounted in the guest > using mount_tag 'host' > > Signed-off-by: Greg Kurz > --- > > Since there has been some activity on 9p again since a few weeks, maybe it > is not too late for 2.6, if everybody agrees the fix is ok ? The patch is good, but I think the subject should be savevm: fail if migration blockers are present The subject you used would be good for the include/migration and migration/migration.c parts alone (where you introduce the function without any semantic change). Apart from this, Reviewed-by: Paolo Bonzini Thanks, Paolo > include/migration/migration.h | 1 + > migration/migration.c | 21 +++++++++++++++------ > migration/savevm.c | 2 +- > 3 files changed, 17 insertions(+), 7 deletions(-) > > diff --git a/include/migration/migration.h b/include/migration/migration.h > index ac2c12c2a518..9e36a97fc5e5 100644 > --- a/include/migration/migration.h > +++ b/include/migration/migration.h > @@ -210,6 +210,7 @@ int migrate_fd_close(MigrationState *s); > void add_migration_state_change_notifier(Notifier *notify); > void remove_migration_state_change_notifier(Notifier *notify); > MigrationState *migrate_init(const MigrationParams *params); > +bool migration_is_blocked(Error **errp); > bool migration_in_setup(MigrationState *); > bool migration_has_finished(MigrationState *); > bool migration_has_failed(MigrationState *); > diff --git a/migration/migration.c b/migration/migration.c > index 991313a8629a..afd883b78179 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -992,6 +992,20 @@ void qmp_migrate_incoming(const char *uri, Error **errp) > once = false; > } > > +bool migration_is_blocked(Error **errp) > +{ > + if (qemu_savevm_state_blocked(errp)) { > + return true; > + } > + > + if (migration_blockers) { > + *errp = error_copy(migration_blockers->data); > + return true; > + } > + > + return false; > +} > + > void qmp_migrate(const char *uri, bool has_blk, bool blk, > bool has_inc, bool inc, bool has_detach, bool detach, > Error **errp) > @@ -1014,12 +1028,7 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk, > return; > } > > - if (qemu_savevm_state_blocked(errp)) { > - return; > - } > - > - if (migration_blockers) { > - *errp = error_copy(migration_blockers->data); > + if (migration_is_blocked(errp)) { > return; > } > > diff --git a/migration/savevm.c b/migration/savevm.c > index 16ba44379870..834664936dfc 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -1169,7 +1169,7 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp) > MigrationState *ms = migrate_init(¶ms); > ms->to_dst_file = f; > > - if (qemu_savevm_state_blocked(errp)) { > + if (migration_is_blocked(errp)) { > return -EINVAL; > } > > > >