Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
  dm snapshot: wait for chunks in destructor
  dm snapshot: fix register_snapshot deadlock
  dm raid1: fix do_failures

3 files changed, 28 insertions, 9 deletions

diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 92dcc06832a..9d7b53ed75b 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -656,9 +656,10 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures)
 		return;
 
 	if (!ms->log_failure) {
-		while ((bio = bio_list_pop(failures)))
+		while ((bio = bio_list_pop(failures))) {
 			ms->in_sync = 0;
 			dm_rh_mark_nosync(ms->rh, bio, bio->bi_size, 0);
+		}
 		return;
 	}
 
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index b2d9d1ac28a..6c96db26b87 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -229,19 +229,21 @@ static void __insert_origin(struct origin *o)
  */
 static int register_snapshot(struct dm_snapshot *snap)
 {
-	struct origin *o;
+	struct origin *o, *new_o;
 	struct block_device *bdev = snap->origin->bdev;
 
+	new_o = kmalloc(sizeof(*new_o), GFP_KERNEL);
+	if (!new_o)
+		return -ENOMEM;
+
 	down_write(&_origins_lock);
 	o = __lookup_origin(bdev);
 
-	if (!o) {
+	if (o)
+		kfree(new_o);
+	else {
 		/* New origin */
-		o = kmalloc(sizeof(*o), GFP_KERNEL);
-		if (!o) {
-			up_write(&_origins_lock);
-			return -ENOMEM;
-		}
+		o = new_o;
 
 		/* Initialise the struct */
 		INIT_LIST_HEAD(&o->snapshots);
@@ -368,6 +370,7 @@ static struct dm_snap_pending_exception *alloc_pending_exception(struct dm_snaps
 	struct dm_snap_pending_exception *pe = mempool_alloc(s->pending_pool,
 							     GFP_NOIO);
 
+	atomic_inc(&s->pending_exceptions_count);
 	pe->snap = s;
 
 	return pe;
@@ -375,7 +378,11 @@ static struct dm_snap_pending_exception *alloc_pending_exception(struct dm_snaps
 
 static void free_pending_exception(struct dm_snap_pending_exception *pe)
 {
-	mempool_free(pe, pe->snap->pending_pool);
+	struct dm_snapshot *s = pe->snap;
+
+	mempool_free(pe, s->pending_pool);
+	smp_mb__before_atomic_dec();
+	atomic_dec(&s->pending_exceptions_count);
 }
 
 static void insert_completed_exception(struct dm_snapshot *s,
@@ -600,6 +607,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	s->valid = 1;
 	s->active = 0;
+	atomic_set(&s->pending_exceptions_count, 0);
 	init_rwsem(&s->lock);
 	spin_lock_init(&s->pe_lock);
 	s->ti = ti;
@@ -726,6 +734,14 @@ static void snapshot_dtr(struct dm_target *ti)
 	/* After this returns there can be no new kcopyd jobs. */
 	unregister_snapshot(s);
 
+	while (atomic_read(&s->pending_exceptions_count))
+		yield();
+	/*
+	 * Ensure instructions in mempool_destroy aren't reordered
+	 * before atomic_read.
+	 */
+	smp_mb();
+
 #ifdef CONFIG_DM_DEBUG
 	for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++)
 		BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i]));
diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h
index f07315fe236..99c0106ede2 100644
--- a/drivers/md/dm-snap.h
+++ b/drivers/md/dm-snap.h
@@ -160,6 +160,8 @@ struct dm_snapshot {
 
 	mempool_t *pending_pool;
 
+	atomic_t pending_exceptions_count;
+
 	struct exception_table pending;
 	struct exception_table complete;