Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756117AbZKTU3O (ORCPT ); Fri, 20 Nov 2009 15:29:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756050AbZKTU3H (ORCPT ); Fri, 20 Nov 2009 15:29:07 -0500 Received: from mx1.redhat.com ([209.132.183.28]:4535 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755921AbZKTU1x (ORCPT ); Fri, 20 Nov 2009 15:27:53 -0500 From: Mike Snitzer To: dm-devel@redhat.com Cc: linux-kernel@vger.kernel.org, Mikulas Patocka Subject: [PATCH v4 07/13] dm snapshot: do not allow more than one merging snapshot. Date: Fri, 20 Nov 2009 15:27:47 -0500 Message-Id: <1258748873-24185-8-git-send-email-snitzer@redhat.com> In-Reply-To: <1258748873-24185-1-git-send-email-snitzer@redhat.com> References: <1258748873-24185-1-git-send-email-snitzer@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2109 Lines: 84 From: Mikulas Patocka Merging more than one snapshot is not supported. __find_merging_snapshot() will find the merging snapshot for a given origin device. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- drivers/md/dm-snap.c | 35 +++++++++++++++++++++++++++++++++-- 1 files changed, 33 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index b8838e7..f4e9aa6 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -332,9 +332,29 @@ out: return count; } +static struct dm_snapshot *__find_merging_snapshot(struct block_device *origin) +{ + struct dm_snapshot *s, *merging_snap; + struct origin *o; + + o = __lookup_origin(origin); + if (!o) + return NULL; + + list_for_each_entry(s, &o->snapshots, list) { + if (is_merge(s->ti)) { + merging_snap = s; + break; + } + } + + return merging_snap; +} + static int __validate_exception_handover(struct dm_snapshot *snap) { struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; + struct block_device *bdev = snap->origin->bdev; int r = 0; /* Does snapshot need exceptions handed over to it? */ @@ -346,8 +366,19 @@ static int __validate_exception_handover(struct dm_snapshot *snap) goto out; } - if (snap_src) + if (snap_src) { + if (is_merge(snap->ti)) { + /* Do not allow more than one merging snapshot */ + if (__find_merging_snapshot(bdev)) { + snap->ti->error = "A snapshot is already " + "merging."; + r = -EINVAL; + goto out; + } + } + r = 1; + } out: return r; @@ -1325,7 +1356,7 @@ static int snapshot_merge_map(struct dm_target *ti, struct bio *bio, bio->bi_bdev = s->origin->bdev; if (bio_rw(bio) == WRITE) { - up_write(&s->lock); + up_read(&s->lock); return do_origin(s->origin, bio); } -- 1.6.5.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/