From patchwork Tue Mar 17 14:05:31 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonthan Brassow X-Patchwork-Id: 12621 Received: from hormel.redhat.com (hormel1.redhat.com [209.132.177.33]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n2HE5ZVm018730 for ; Tue, 17 Mar 2009 14:05:35 GMT Received: from listman.util.phx.redhat.com (listman.util.phx.redhat.com [10.8.4.110]) by hormel.redhat.com (Postfix) with ESMTP id D7795619B5A; Tue, 17 Mar 2009 10:05:35 -0400 (EDT) Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by listman.util.phx.redhat.com (8.13.1/8.13.1) with ESMTP id n2HE5XH8023687 for ; Tue, 17 Mar 2009 10:05:33 -0400 Received: from hydrogen.msp.redhat.com (hydrogen.msp.redhat.com [10.15.80.1]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n2HE5X4B007771 for ; Tue, 17 Mar 2009 10:05:33 -0400 Received: from hydrogen.msp.redhat.com (localhost.localdomain [127.0.0.1]) by hydrogen.msp.redhat.com (8.14.1/8.14.1) with ESMTP id n2HE5VGY017487 for ; Tue, 17 Mar 2009 09:05:31 -0500 Received: (from jbrassow@localhost) by hydrogen.msp.redhat.com (8.14.1/8.14.1/Submit) id n2HE5V27017485 for dm-devel@redhat.com; Tue, 17 Mar 2009 09:05:31 -0500 Date: Tue, 17 Mar 2009 09:05:31 -0500 From: Jonathan Brassow Message-Id: <200903171405.n2HE5V27017485@hydrogen.msp.redhat.com> To: dm-devel@redhat.com X-Scanned-By: MIMEDefang 2.58 on 172.16.52.254 X-loop: dm-devel@redhat.com Subject: [dm-devel] [PATCH 20 of 29] dm-exception-store-add-suspend-to-API.patch X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.5 Precedence: junk Reply-To: device-mapper development List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com Add [pre|post]suspend functions to the exception store API. These will become important for future exception stores. Current exception store implementations will not alter metadata after a 'commit_exception' completes. However, future stores may do journaling or other actions. They might return from 'commit_exception' when the request hits the journal, but continue flushing after. This could be bad, because we expect them to not do anything once a 'suspend' is issued. Adding these functions to the API allows them to finish what they are doing and conform to device-mapper requirements. (The above was just one example... Cluster-aware exception stores will also require the notification of when they need to suspend their activity.) RFC-by: Jonathan Brassow --- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel Index: linux-2.6/drivers/md/dm-exception-store.h =================================================================== --- linux-2.6.orig/drivers/md/dm-exception-store.h +++ linux-2.6/drivers/md/dm-exception-store.h @@ -32,6 +32,8 @@ struct dm_exception_store_type { void (*dtr) (struct dm_exception_store *store); int (*resume) (struct dm_exception_store *store); + void (*presuspend) (struct dm_exception_store *store); + void (*postsuspend) (struct dm_exception_store *store); /* * Find somewhere to store the next exception. Index: linux-2.6/drivers/md/dm-snap.c =================================================================== --- linux-2.6.orig/drivers/md/dm-snap.c +++ linux-2.6/drivers/md/dm-snap.c @@ -1001,6 +1001,22 @@ static void snapshot_resume(struct dm_ta up_write(&s->lock); } +static void snapshot_presuspend(struct dm_target *ti) +{ + struct dm_snapshot *s = ti->private; + + if(s->store->type->presuspend) + s->store->type->presuspend(s->store); +} + +static void snapshot_postsuspend(struct dm_target *ti) +{ + struct dm_snapshot *s = ti->private; + + if (s->store->type->postsuspend) + s->store->type->postsuspend(s->store); +} + static int snapshot_status(struct dm_target *ti, status_type_t type, char *result, unsigned int maxlen) { @@ -1280,6 +1296,8 @@ static struct target_type snapshot_targe .map = snapshot_map, .end_io = snapshot_end_io, .resume = snapshot_resume, + .presuspend = snapshot_presuspend, + .postsuspend = snapshot_postsuspend, .status = snapshot_status, };