From patchwork Tue Nov 17 16:12:16 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Snitzer X-Patchwork-Id: 60703 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 nAHGCgfG001731 for ; Tue, 17 Nov 2009 16:12:42 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 49C2661B0DA; Tue, 17 Nov 2009 11:12:32 -0500 (EST) Received: from int-mx04.intmail.prod.int.phx2.redhat.com (nat-pool.util.phx.redhat.com [10.8.5.200]) by listman.util.phx.redhat.com (8.13.1/8.13.1) with ESMTP id nAHGCRGG030011 for ; Tue, 17 Nov 2009 11:12:27 -0500 Received: from localhost (dhcp-100-19-150.bos.redhat.com [10.16.19.150]) by int-mx04.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id nAHGCRHS025527 for ; Tue, 17 Nov 2009 11:12:27 -0500 From: Mike Snitzer To: dm-devel@redhat.com Date: Tue, 17 Nov 2009 11:12:16 -0500 Message-Id: <1258474344-10886-5-git-send-email-snitzer@redhat.com> In-Reply-To: <1258474344-10886-1-git-send-email-snitzer@redhat.com> References: <1258474344-10886-1-git-send-email-snitzer@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.17 X-loop: dm-devel@redhat.com Subject: [dm-devel] [PATCH v3 04/12] dm snapshot: merge target should not allocate new exceptions 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 diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 51bc74f..5fd7055 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -143,6 +143,11 @@ static int bdev_equal(struct block_device *lhs, struct block_device *rhs) return lhs == rhs; } +static int snapshot_merge_map(struct dm_target *ti, struct bio *bio, + union map_info *map_context); + +#define is_merge(ti) ((ti)->type->map == snapshot_merge_map) + struct dm_snap_pending_exception { struct dm_exception e; @@ -1256,6 +1261,40 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, return r; } +static int snapshot_merge_map(struct dm_target *ti, struct bio *bio, + union map_info *map_context) +{ + struct dm_exception *e; + struct dm_snapshot *s = ti->private; + int r = DM_MAPIO_REMAPPED; + chunk_t chunk; + + chunk = sector_to_chunk(s->store, bio->bi_sector); + + down_read(&s->lock); + + /* Full snapshots are not usable */ + if (!s->valid) { + r = -EIO; + goto out_unlock; + } + + /* If the block is already remapped - use that */ + e = dm_lookup_exception(&s->complete, chunk); + if (e) { + remap_exception(s, e, bio, chunk); + goto out_unlock; + } + + bio->bi_bdev = s->origin->bdev; + + out_unlock: + up_read(&s->lock); + + return r; +} + + static int snapshot_end_io(struct dm_target *ti, struct bio *bio, int error, union map_info *map_context) { @@ -1425,6 +1464,11 @@ static int __origin_write(struct list_head *snapshots, /* Do all the snapshots on this origin */ list_for_each_entry (snap, snapshots, list) { + /* If the snapshot is merging, don't make new exceptions in it + - but in this case no one should be writing to the origin */ + if (is_merge(snap->ti)) + continue; + down_write(&snap->lock); /* Only deal with valid and active snapshots */ @@ -1653,7 +1697,7 @@ static struct target_type merge_target = { .module = THIS_MODULE, .ctr = snapshot_ctr, .dtr = snapshot_dtr, - .map = snapshot_map, + .map = snapshot_merge_map, .end_io = snapshot_end_io, .postsuspend = snapshot_postsuspend, .preresume = snapshot_preresume,