1 files changed, 49 insertions, 71 deletions

diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index a143921feaf6..c0e07026a8d1 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -79,7 +79,6 @@ struct dm_snapshot {
 
 	/* Chunks with outstanding reads */
 	spinlock_t tracked_chunk_lock;
-	mempool_t *tracked_chunk_pool;
 	struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
 
 	/* The on disk metadata handler */
@@ -125,6 +124,9 @@ struct dm_snapshot {
 #define RUNNING_MERGE          0
 #define SHUTDOWN_MERGE         1
 
+DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
+		"A percentage of time allocated for copy on write");
+
 struct dm_dev *dm_snap_origin(struct dm_snapshot *s)
 {
 	return s->origin;
@@ -191,46 +193,48 @@ struct dm_snap_tracked_chunk {
 	chunk_t chunk;
 };
 
-static struct kmem_cache *tracked_chunk_cache;
+static void init_tracked_chunk(struct bio *bio)
+{
+	struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk));
+	INIT_HLIST_NODE(&c->node);
+}
 
-static struct dm_snap_tracked_chunk *track_chunk(struct dm_snapshot *s,
-						 chunk_t chunk)
+static bool is_bio_tracked(struct bio *bio)
 {
-	struct dm_snap_tracked_chunk *c = mempool_alloc(s->tracked_chunk_pool,
-							GFP_NOIO);
-	unsigned long flags;
+	struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk));
+	return !hlist_unhashed(&c->node);
+}
+
+static void track_chunk(struct dm_snapshot *s, struct bio *bio, chunk_t chunk)
+{
+	struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk));
 
 	c->chunk = chunk;
 
-	spin_lock_irqsave(&s->tracked_chunk_lock, flags);
+	spin_lock_irq(&s->tracked_chunk_lock);
 	hlist_add_head(&c->node,
 		       &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)]);
-	spin_unlock_irqrestore(&s->tracked_chunk_lock, flags);
-
-	return c;
+	spin_unlock_irq(&s->tracked_chunk_lock);
 }
 
-static void stop_tracking_chunk(struct dm_snapshot *s,
-				struct dm_snap_tracked_chunk *c)
+static void stop_tracking_chunk(struct dm_snapshot *s, struct bio *bio)
 {
+	struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk));
 	unsigned long flags;
 
 	spin_lock_irqsave(&s->tracked_chunk_lock, flags);
 	hlist_del(&c->node);
 	spin_unlock_irqrestore(&s->tracked_chunk_lock, flags);
-
-	mempool_free(c, s->tracked_chunk_pool);
 }
 
 static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk)
 {
 	struct dm_snap_tracked_chunk *c;
-	struct hlist_node *hn;
 	int found = 0;
 
 	spin_lock_irq(&s->tracked_chunk_lock);
 
-	hlist_for_each_entry(c, hn,
+	hlist_for_each_entry(c,
 	    &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)], node) {
 		if (c->chunk == chunk) {
 			found = 1;
@@ -1036,7 +1040,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	int i;
 	int r = -EINVAL;
 	char *origin_path, *cow_path;
-	unsigned args_used, num_flush_requests = 1;
+	unsigned args_used, num_flush_bios = 1;
 	fmode_t origin_mode = FMODE_READ;
 
 	if (argc != 4) {
@@ -1046,7 +1050,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 
 	if (dm_target_is_snapshot_merge(ti)) {
-		num_flush_requests = 2;
+		num_flush_bios = 2;
 		origin_mode = FMODE_WRITE;
 	}
 
@@ -1107,7 +1111,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad_hash_tables;
 	}
 
-	s->kcopyd_client = dm_kcopyd_client_create();
+	s->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle);
 	if (IS_ERR(s->kcopyd_client)) {
 		r = PTR_ERR(s->kcopyd_client);
 		ti->error = "Could not create kcopyd client";
@@ -1120,21 +1124,14 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad_pending_pool;
 	}
 
-	s->tracked_chunk_pool = mempool_create_slab_pool(MIN_IOS,
-							 tracked_chunk_cache);
-	if (!s->tracked_chunk_pool) {
-		ti->error = "Could not allocate tracked_chunk mempool for "
-			    "tracking reads";
-		goto bad_tracked_chunk_pool;
-	}
-
 	for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++)
 		INIT_HLIST_HEAD(&s->tracked_chunk_hash[i]);
 
 	spin_lock_init(&s->tracked_chunk_lock);
 
 	ti->private = s;
-	ti->num_flush_requests = num_flush_requests;
+	ti->num_flush_bios = num_flush_bios;
+	ti->per_bio_data_size = sizeof(struct dm_snap_tracked_chunk);
 
 	/* Add snapshot to the list of snapshots for this origin */
 	/* Exceptions aren't triggered till snapshot_resume() is called */
@@ -1183,9 +1180,6 @@ bad_read_metadata:
 	unregister_snapshot(s);
 
 bad_load_and_register:
-	mempool_destroy(s->tracked_chunk_pool);
-
-bad_tracked_chunk_pool:
 	mempool_destroy(s->pending_pool);
 
 bad_pending_pool:
@@ -1290,8 +1284,6 @@ static void snapshot_dtr(struct dm_target *ti)
 		BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i]));
 #endif
 
-	mempool_destroy(s->tracked_chunk_pool);
-
 	__free_exceptions(s);
 
 	mempool_destroy(s->pending_pool);
@@ -1577,8 +1569,7 @@ static void remap_exception(struct dm_snapshot *s, struct dm_exception *e,
 					  s->store->chunk_mask);
 }
 
-static int snapshot_map(struct dm_target *ti, struct bio *bio,
-			union map_info *map_context)
+static int snapshot_map(struct dm_target *ti, struct bio *bio)
 {
 	struct dm_exception *e;
 	struct dm_snapshot *s = ti->private;
@@ -1586,6 +1577,8 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
 	chunk_t chunk;
 	struct dm_snap_pending_exception *pe = NULL;
 
+	init_tracked_chunk(bio);
+
 	if (bio->bi_rw & REQ_FLUSH) {
 		bio->bi_bdev = s->cow->bdev;
 		return DM_MAPIO_REMAPPED;
@@ -1670,7 +1663,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
 		}
 	} else {
 		bio->bi_bdev = s->origin->bdev;
-		map_context->ptr = track_chunk(s, chunk);
+		track_chunk(s, bio, chunk);
 	}
 
 out_unlock:
@@ -1691,20 +1684,20 @@ out:
  * If merging is currently taking place on the chunk in question, the
  * I/O is deferred by adding it to s->bios_queued_during_merge.
  */
-static int snapshot_merge_map(struct dm_target *ti, struct bio *bio,
-			      union map_info *map_context)
+static int snapshot_merge_map(struct dm_target *ti, struct bio *bio)
 {
 	struct dm_exception *e;
 	struct dm_snapshot *s = ti->private;
 	int r = DM_MAPIO_REMAPPED;
 	chunk_t chunk;
 
+	init_tracked_chunk(bio);
+
 	if (bio->bi_rw & REQ_FLUSH) {
-		if (!map_context->target_request_nr)
+		if (!dm_bio_get_target_bio_nr(bio))
 			bio->bi_bdev = s->origin->bdev;
 		else
 			bio->bi_bdev = s->cow->bdev;
-		map_context->ptr = NULL;
 		return DM_MAPIO_REMAPPED;
 	}
 
@@ -1733,7 +1726,7 @@ static int snapshot_merge_map(struct dm_target *ti, struct bio *bio,
 		remap_exception(s, e, bio, chunk);
 
 		if (bio_rw(bio) == WRITE)
-			map_context->ptr = track_chunk(s, chunk);
+			track_chunk(s, bio, chunk);
 		goto out_unlock;
 	}
 
@@ -1751,14 +1744,12 @@ out_unlock:
 	return r;
 }
 
-static int snapshot_end_io(struct dm_target *ti, struct bio *bio,
-			   int error, union map_info *map_context)
+static int snapshot_end_io(struct dm_target *ti, struct bio *bio, int error)
 {
 	struct dm_snapshot *s = ti->private;
-	struct dm_snap_tracked_chunk *c = map_context->ptr;
 
-	if (c)
-		stop_tracking_chunk(s, c);
+	if (is_bio_tracked(bio))
+		stop_tracking_chunk(s, bio);
 
 	return 0;
 }
@@ -1848,8 +1839,8 @@ static void snapshot_merge_resume(struct dm_target *ti)
 	start_merge(s);
 }
 
-static int snapshot_status(struct dm_target *ti, status_type_t type,
-			   unsigned status_flags, char *result, unsigned maxlen)
+static void snapshot_status(struct dm_target *ti, status_type_t type,
+			    unsigned status_flags, char *result, unsigned maxlen)
 {
 	unsigned sz = 0;
 	struct dm_snapshot *snap = ti->private;
@@ -1895,8 +1886,6 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
 					  maxlen - sz);
 		break;
 	}
-
-	return 0;
 }
 
 static int snapshot_iterate_devices(struct dm_target *ti,
@@ -2116,7 +2105,7 @@ static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 
 	ti->private = dev;
-	ti->num_flush_requests = 1;
+	ti->num_flush_bios = 1;
 
 	return 0;
 }
@@ -2127,8 +2116,7 @@ static void origin_dtr(struct dm_target *ti)
 	dm_put_device(ti, dev);
 }
 
-static int origin_map(struct dm_target *ti, struct bio *bio,
-		      union map_info *map_context)
+static int origin_map(struct dm_target *ti, struct bio *bio)
 {
 	struct dm_dev *dev = ti->private;
 	bio->bi_bdev = dev->bdev;
@@ -2151,8 +2139,8 @@ static void origin_resume(struct dm_target *ti)
 	ti->max_io_len = get_origin_minimum_chunksize(dev->bdev);
 }
 
-static int origin_status(struct dm_target *ti, status_type_t type,
-			 unsigned status_flags, char *result, unsigned maxlen)
+static void origin_status(struct dm_target *ti, status_type_t type,
+			  unsigned status_flags, char *result, unsigned maxlen)
 {
 	struct dm_dev *dev = ti->private;
 
@@ -2165,8 +2153,6 @@ static int origin_status(struct dm_target *ti, status_type_t type,
 		snprintf(result, maxlen, "%s", dev->name);
 		break;
 	}
-
-	return 0;
 }
 
 static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
@@ -2193,7 +2179,7 @@ static int origin_iterate_devices(struct dm_target *ti,
 
 static struct target_type origin_target = {
 	.name    = "snapshot-origin",
-	.version = {1, 7, 1},
+	.version = {1, 8, 1},
 	.module  = THIS_MODULE,
 	.ctr     = origin_ctr,
 	.dtr     = origin_dtr,
@@ -2206,7 +2192,7 @@ static struct target_type origin_target = {
 
 static struct target_type snapshot_target = {
 	.name    = "snapshot",
-	.version = {1, 10, 0},
+	.version = {1, 11, 1},
 	.module  = THIS_MODULE,
 	.ctr     = snapshot_ctr,
 	.dtr     = snapshot_dtr,
@@ -2220,7 +2206,7 @@ static struct target_type snapshot_target = {
 
 static struct target_type merge_target = {
 	.name    = dm_snapshot_merge_target_name,
-	.version = {1, 1, 0},
+	.version = {1, 2, 0},
 	.module  = THIS_MODULE,
 	.ctr     = snapshot_ctr,
 	.dtr     = snapshot_dtr,
@@ -2281,17 +2267,8 @@ static int __init dm_snapshot_init(void)
 		goto bad_pending_cache;
 	}
 
-	tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0);
-	if (!tracked_chunk_cache) {
-		DMERR("Couldn't create cache to track chunks in use.");
-		r = -ENOMEM;
-		goto bad_tracked_chunk_cache;
-	}
-
 	return 0;
 
-bad_tracked_chunk_cache:
-	kmem_cache_destroy(pending_cache);
 bad_pending_cache:
 	kmem_cache_destroy(exception_cache);
 bad_exception_cache:
@@ -2317,7 +2294,6 @@ static void __exit dm_snapshot_exit(void)
 	exit_origin_hash();
 	kmem_cache_destroy(pending_cache);
 	kmem_cache_destroy(exception_cache);
-	kmem_cache_destroy(tracked_chunk_cache);
 
 	dm_exception_store_exit();
 }
@@ -2329,3 +2305,5 @@ module_exit(dm_snapshot_exit);
 MODULE_DESCRIPTION(DM_NAME " snapshot target");
 MODULE_AUTHOR("Joe Thornber");
 MODULE_LICENSE("GPL");
+MODULE_ALIAS("dm-snapshot-origin");
+MODULE_ALIAS("dm-snapshot-merge");