From 35eb8c635db726772adee86a8d0fdc5892424fae Mon Sep 17 00:00:00 2001
From: Alasdair G Kergon <agk@redhat.com>
Date: Wed, 1 Feb 2006 03:04:50 -0800
Subject: [PATCH] --- yaml --- r: 19325 b: refs/heads/master c:
 aa14edeb994f8f7e223d02ad14780bf2fa719f6d h: refs/heads/master i:   19323:
 c1d658503ee3b8c22d42e4ba7a6b428e2c0a574c v: v3

---
 [refs]                     |  2 +-
 trunk/drivers/md/dm-snap.c | 23 ++++++++++++-----------
 trunk/drivers/md/dm-snap.h |  4 +++-
 3 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/[refs] b/[refs]
index daa4d0dd615c..15ba7b7be708 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: cb82a6cdf994d6656ad0a25ed28395af3416a27c
+refs/heads/master: aa14edeb994f8f7e223d02ad14780bf2fa719f6d
diff --git a/trunk/drivers/md/dm-snap.c b/trunk/drivers/md/dm-snap.c
index 87727d84dbba..ad9b61f16c5e 100644
--- a/trunk/drivers/md/dm-snap.c
+++ b/trunk/drivers/md/dm-snap.c
@@ -373,16 +373,11 @@ static inline ulong round_up(ulong n, ulong size)
 
 static void read_snapshot_metadata(struct dm_snapshot *s)
 {
-	if (s->have_metadata)
-		return;
-
 	if (s->store.read_metadata(&s->store)) {
 		down_write(&s->lock);
 		s->valid = 0;
 		up_write(&s->lock);
 	}
-
-	s->have_metadata = 1;
 }
 
 /*
@@ -471,7 +466,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	s->chunk_shift = ffs(chunk_size) - 1;
 
 	s->valid = 1;
-	s->have_metadata = 0;
+	s->active = 0;
 	s->last_percent = 0;
 	init_rwsem(&s->lock);
 	s->table = ti->table;
@@ -506,7 +501,11 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad5;
 	}
 
+	/* Metadata must only be loaded into one table at once */
+	read_snapshot_metadata(s);
+
 	/* Add snapshot to the list of snapshots for this origin */
+	/* Exceptions aren't triggered till snapshot_resume() is called */
 	if (register_snapshot(s)) {
 		r = -EINVAL;
 		ti->error = "Cannot register snapshot origin";
@@ -862,7 +861,9 @@ static void snapshot_resume(struct dm_target *ti)
 {
 	struct dm_snapshot *s = (struct dm_snapshot *) ti->private;
 
-	read_snapshot_metadata(s);
+	down_write(&s->lock);
+	s->active = 1;
+	up_write(&s->lock);
 }
 
 static int snapshot_status(struct dm_target *ti, status_type_t type,
@@ -932,8 +933,8 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
 	/* Do all the snapshots on this origin */
 	list_for_each_entry (snap, snapshots, list) {
 
-		/* Only deal with valid snapshots */
-		if (!snap->valid)
+		/* Only deal with valid and active snapshots */
+		if (!snap->valid || !snap->active)
 			continue;
 
 		/* Nothing to do if writing beyond end of snapshot */
@@ -1104,7 +1105,7 @@ static int origin_status(struct dm_target *ti, status_type_t type, char *result,
 
 static struct target_type origin_target = {
 	.name    = "snapshot-origin",
-	.version = {1, 0, 1},
+	.version = {1, 1, 0},
 	.module  = THIS_MODULE,
 	.ctr     = origin_ctr,
 	.dtr     = origin_dtr,
@@ -1115,7 +1116,7 @@ static struct target_type origin_target = {
 
 static struct target_type snapshot_target = {
 	.name    = "snapshot",
-	.version = {1, 0, 1},
+	.version = {1, 1, 0},
 	.module  = THIS_MODULE,
 	.ctr     = snapshot_ctr,
 	.dtr     = snapshot_dtr,
diff --git a/trunk/drivers/md/dm-snap.h b/trunk/drivers/md/dm-snap.h
index 375aa24d4d7d..fdec1e2dc871 100644
--- a/trunk/drivers/md/dm-snap.h
+++ b/trunk/drivers/md/dm-snap.h
@@ -99,7 +99,9 @@ struct dm_snapshot {
 
 	/* You can't use a snapshot if this is 0 (e.g. if full) */
 	int valid;
-	int have_metadata;
+
+	/* Origin writes don't trigger exceptions until this is set */
+	int active;
 
 	/* Used for display of table */
 	char type;