1 files changed, 225 insertions, 187 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 3de11f077144..a999b698b131 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -632,9 +632,8 @@ void rbd_warn(struct rbd_device *rbd_dev, const char *fmt, ...)
 static void rbd_dev_remove_parent(struct rbd_device *rbd_dev);
 
 static int rbd_dev_refresh(struct rbd_device *rbd_dev);
-static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev);
-static int rbd_dev_header_info(struct rbd_device *rbd_dev);
-static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev);
+static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev,
+				     struct rbd_image_header *header);
 static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,
 					u64 snap_id);
 static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
@@ -995,15 +994,24 @@ static void rbd_init_layout(struct rbd_device *rbd_dev)
 	RCU_INIT_POINTER(rbd_dev->layout.pool_ns, NULL);
 }
 
+static void rbd_image_header_cleanup(struct rbd_image_header *header)
+{
+	kfree(header->object_prefix);
+	ceph_put_snap_context(header->snapc);
+	kfree(header->snap_sizes);
+	kfree(header->snap_names);
+
+	memset(header, 0, sizeof(*header));
+}
+
 /*
  * Fill an rbd image header with information from the given format 1
  * on-disk header.
  */
-static int rbd_header_from_disk(struct rbd_device *rbd_dev,
-				 struct rbd_image_header_ondisk *ondisk)
+static int rbd_header_from_disk(struct rbd_image_header *header,
+				struct rbd_image_header_ondisk *ondisk,
+				bool first_time)
 {
-	struct rbd_image_header *header = &rbd_dev->header;
-	bool first_time = header->object_prefix == NULL;
 	struct ceph_snap_context *snapc;
 	char *object_prefix = NULL;
 	char *snap_names = NULL;
@@ -1070,11 +1078,6 @@ static int rbd_header_from_disk(struct rbd_device *rbd_dev,
 	if (first_time) {
 		header->object_prefix = object_prefix;
 		header->obj_order = ondisk->options.order;
-		rbd_init_layout(rbd_dev);
-	} else {
-		ceph_put_snap_context(header->snapc);
-		kfree(header->snap_names);
-		kfree(header->snap_sizes);
 	}
 
 	/* The remaining fields always get updated (when we refresh) */
@@ -4859,7 +4862,9 @@ out_req:
  * return, the rbd_dev->header field will contain up-to-date
  * information about the image.
  */
-static int rbd_dev_v1_header_info(struct rbd_device *rbd_dev)
+static int rbd_dev_v1_header_info(struct rbd_device *rbd_dev,
+				  struct rbd_image_header *header,
+				  bool first_time)
 {
 	struct rbd_image_header_ondisk *ondisk = NULL;
 	u32 snap_count = 0;
@@ -4907,7 +4912,7 @@ static int rbd_dev_v1_header_info(struct rbd_device *rbd_dev)
 		snap_count = le32_to_cpu(ondisk->snap_count);
 	} while (snap_count != want_count);
 
-	ret = rbd_header_from_disk(rbd_dev, ondisk);
+	ret = rbd_header_from_disk(header, ondisk, first_time);
 out:
 	kfree(ondisk);
 
@@ -4931,39 +4936,6 @@ static void rbd_dev_update_size(struct rbd_device *rbd_dev)
 	}
 }
 
-static int rbd_dev_refresh(struct rbd_device *rbd_dev)
-{
-	u64 mapping_size;
-	int ret;
-
-	down_write(&rbd_dev->header_rwsem);
-	mapping_size = rbd_dev->mapping.size;
-
-	ret = rbd_dev_header_info(rbd_dev);
-	if (ret)
-		goto out;
-
-	/*
-	 * If there is a parent, see if it has disappeared due to the
-	 * mapped image getting flattened.
-	 */
-	if (rbd_dev->parent) {
-		ret = rbd_dev_v2_parent_info(rbd_dev);
-		if (ret)
-			goto out;
-	}
-
-	rbd_assert(!rbd_is_snap(rbd_dev));
-	rbd_dev->mapping.size = rbd_dev->header.image_size;
-
-out:
-	up_write(&rbd_dev->header_rwsem);
-	if (!ret && mapping_size != rbd_dev->mapping.size)
-		rbd_dev_update_size(rbd_dev);
-
-	return ret;
-}
-
 static const struct blk_mq_ops rbd_mq_ops = {
 	.queue_rq	= rbd_queue_rq,
 };
@@ -5503,17 +5475,12 @@ static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
 	return 0;
 }
 
-static int rbd_dev_v2_image_size(struct rbd_device *rbd_dev)
-{
-	return _rbd_dev_v2_snap_size(rbd_dev, CEPH_NOSNAP,
-					&rbd_dev->header.obj_order,
-					&rbd_dev->header.image_size);
-}
-
-static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev)
+static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev,
+				    char **pobject_prefix)
 {
 	size_t size;
 	void *reply_buf;
+	char *object_prefix;
 	int ret;
 	void *p;
 
@@ -5531,16 +5498,16 @@ static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev)
 		goto out;
 
 	p = reply_buf;
-	rbd_dev->header.object_prefix = ceph_extract_encoded_string(&p,
-						p + ret, NULL, GFP_NOIO);
+	object_prefix = ceph_extract_encoded_string(&p, p + ret, NULL,
+						    GFP_NOIO);
+	if (IS_ERR(object_prefix)) {
+		ret = PTR_ERR(object_prefix);
+		goto out;
+	}
 	ret = 0;
 
-	if (IS_ERR(rbd_dev->header.object_prefix)) {
-		ret = PTR_ERR(rbd_dev->header.object_prefix);
-		rbd_dev->header.object_prefix = NULL;
-	} else {
-		dout("  object_prefix = %s\n", rbd_dev->header.object_prefix);
-	}
+	*pobject_prefix = object_prefix;
+	dout("  object_prefix = %s\n", object_prefix);
 out:
 	kfree(reply_buf);
 
@@ -5591,13 +5558,6 @@ static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
 	return 0;
 }
 
-static int rbd_dev_v2_features(struct rbd_device *rbd_dev)
-{
-	return _rbd_dev_v2_snap_features(rbd_dev, CEPH_NOSNAP,
-					 rbd_is_ro(rbd_dev),
-					 &rbd_dev->header.features);
-}
-
 /*
  * These are generic image flags, but since they are used only for
  * object map, store them in rbd_dev->object_map_flags.
@@ -5634,6 +5594,14 @@ struct parent_image_info {
 	u64		overlap;
 };
 
+static void rbd_parent_info_cleanup(struct parent_image_info *pii)
+{
+	kfree(pii->pool_ns);
+	kfree(pii->image_id);
+
+	memset(pii, 0, sizeof(*pii));
+}
+
 /*
  * The caller is responsible for @pii.
  */
@@ -5703,6 +5671,9 @@ static int __get_parent_info(struct rbd_device *rbd_dev,
 	if (pii->has_overlap)
 		ceph_decode_64_safe(&p, end, pii->overlap, e_inval);
 
+	dout("%s pool_id %llu pool_ns %s image_id %s snap_id %llu has_overlap %d overlap %llu\n",
+	     __func__, pii->pool_id, pii->pool_ns, pii->image_id, pii->snap_id,
+	     pii->has_overlap, pii->overlap);
 	return 0;
 
 e_inval:
@@ -5741,14 +5712,17 @@ static int __get_parent_info_legacy(struct rbd_device *rbd_dev,
 	pii->has_overlap = true;
 	ceph_decode_64_safe(&p, end, pii->overlap, e_inval);
 
+	dout("%s pool_id %llu pool_ns %s image_id %s snap_id %llu has_overlap %d overlap %llu\n",
+	     __func__, pii->pool_id, pii->pool_ns, pii->image_id, pii->snap_id,
+	     pii->has_overlap, pii->overlap);
 	return 0;
 
 e_inval:
 	return -EINVAL;
 }
 
-static int get_parent_info(struct rbd_device *rbd_dev,
-			   struct parent_image_info *pii)
+static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev,
+				  struct parent_image_info *pii)
 {
 	struct page *req_page, *reply_page;
 	void *p;
@@ -5776,7 +5750,7 @@ static int get_parent_info(struct rbd_device *rbd_dev,
 	return ret;
 }
 
-static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
+static int rbd_dev_setup_parent(struct rbd_device *rbd_dev)
 {
 	struct rbd_spec *parent_spec;
 	struct parent_image_info pii = { 0 };
@@ -5786,37 +5760,12 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
 	if (!parent_spec)
 		return -ENOMEM;
 
-	ret = get_parent_info(rbd_dev, &pii);
+	ret = rbd_dev_v2_parent_info(rbd_dev, &pii);
 	if (ret)
 		goto out_err;
 
-	dout("%s pool_id %llu pool_ns %s image_id %s snap_id %llu has_overlap %d overlap %llu\n",
-	     __func__, pii.pool_id, pii.pool_ns, pii.image_id, pii.snap_id,
-	     pii.has_overlap, pii.overlap);
-
-	if (pii.pool_id == CEPH_NOPOOL || !pii.has_overlap) {
-		/*
-		 * Either the parent never existed, or we have
-		 * record of it but the image got flattened so it no
-		 * longer has a parent.  When the parent of a
-		 * layered image disappears we immediately set the
-		 * overlap to 0.  The effect of this is that all new
-		 * requests will be treated as if the image had no
-		 * parent.
-		 *
-		 * If !pii.has_overlap, the parent image spec is not
-		 * applicable.  It's there to avoid duplication in each
-		 * snapshot record.
-		 */
-		if (rbd_dev->parent_overlap) {
-			rbd_dev->parent_overlap = 0;
-			rbd_dev_parent_put(rbd_dev);
-			pr_info("%s: clone image has been flattened\n",
-				rbd_dev->disk->disk_name);
-		}
-
+	if (pii.pool_id == CEPH_NOPOOL || !pii.has_overlap)
 		goto out;	/* No parent?  No problem. */
-	}
 
 	/* The ceph file layout needs to fit pool id in 32 bits */
 
@@ -5828,58 +5777,46 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
 	}
 
 	/*
-	 * The parent won't change (except when the clone is
-	 * flattened, already handled that).  So we only need to
-	 * record the parent spec we have not already done so.
+	 * The parent won't change except when the clone is flattened,
+	 * so we only need to record the parent image spec once.
 	 */
-	if (!rbd_dev->parent_spec) {
-		parent_spec->pool_id = pii.pool_id;
-		if (pii.pool_ns && *pii.pool_ns) {
-			parent_spec->pool_ns = pii.pool_ns;
-			pii.pool_ns = NULL;
-		}
-		parent_spec->image_id = pii.image_id;
-		pii.image_id = NULL;
-		parent_spec->snap_id = pii.snap_id;
-
-		rbd_dev->parent_spec = parent_spec;
-		parent_spec = NULL;	/* rbd_dev now owns this */
+	parent_spec->pool_id = pii.pool_id;
+	if (pii.pool_ns && *pii.pool_ns) {
+		parent_spec->pool_ns = pii.pool_ns;
+		pii.pool_ns = NULL;
 	}
+	parent_spec->image_id = pii.image_id;
+	pii.image_id = NULL;
+	parent_spec->snap_id = pii.snap_id;
+
+	rbd_assert(!rbd_dev->parent_spec);
+	rbd_dev->parent_spec = parent_spec;
+	parent_spec = NULL;	/* rbd_dev now owns this */
 
 	/*
-	 * We always update the parent overlap.  If it's zero we issue
-	 * a warning, as we will proceed as if there was no parent.
+	 * Record the parent overlap.  If it's zero, issue a warning as
+	 * we will proceed as if there is no parent.
 	 */
-	if (!pii.overlap) {
-		if (parent_spec) {
-			/* refresh, careful to warn just once */
-			if (rbd_dev->parent_overlap)
-				rbd_warn(rbd_dev,
-				    "clone now standalone (overlap became 0)");
-		} else {
-			/* initial probe */
-			rbd_warn(rbd_dev, "clone is standalone (overlap 0)");
-		}
-	}
+	if (!pii.overlap)
+		rbd_warn(rbd_dev, "clone is standalone (overlap 0)");
 	rbd_dev->parent_overlap = pii.overlap;
 
 out:
 	ret = 0;
 out_err:
-	kfree(pii.pool_ns);
-	kfree(pii.image_id);
+	rbd_parent_info_cleanup(&pii);
 	rbd_spec_put(parent_spec);
 	return ret;
 }
 
-static int rbd_dev_v2_striping_info(struct rbd_device *rbd_dev)
+static int rbd_dev_v2_striping_info(struct rbd_device *rbd_dev,
+				    u64 *stripe_unit, u64 *stripe_count)
 {
 	struct {
 		__le64 stripe_unit;
 		__le64 stripe_count;
 	} __attribute__ ((packed)) striping_info_buf = { 0 };
 	size_t size = sizeof (striping_info_buf);
-	void *p;
 	int ret;
 
 	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
@@ -5891,27 +5828,33 @@ static int rbd_dev_v2_striping_info(struct rbd_device *rbd_dev)
 	if (ret < size)
 		return -ERANGE;
 
-	p = &striping_info_buf;
-	rbd_dev->header.stripe_unit = ceph_decode_64(&p);
-	rbd_dev->header.stripe_count = ceph_decode_64(&p);
+	*stripe_unit = le64_to_cpu(striping_info_buf.stripe_unit);
+	*stripe_count = le64_to_cpu(striping_info_buf.stripe_count);
+	dout("  stripe_unit = %llu stripe_count = %llu\n", *stripe_unit,
+	     *stripe_count);
+
 	return 0;
 }
 
-static int rbd_dev_v2_data_pool(struct rbd_device *rbd_dev)
+static int rbd_dev_v2_data_pool(struct rbd_device *rbd_dev, s64 *data_pool_id)
 {
-	__le64 data_pool_id;
+	__le64 data_pool_buf;
 	int ret;
 
 	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
 				  &rbd_dev->header_oloc, "get_data_pool",
-				  NULL, 0, &data_pool_id, sizeof(data_pool_id));
+				  NULL, 0, &data_pool_buf,
+				  sizeof(data_pool_buf));
+	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret < 0)
 		return ret;
-	if (ret < sizeof(data_pool_id))
+	if (ret < sizeof(data_pool_buf))
 		return -EBADMSG;
 
-	rbd_dev->header.data_pool_id = le64_to_cpu(data_pool_id);
-	WARN_ON(rbd_dev->header.data_pool_id == CEPH_NOPOOL);
+	*data_pool_id = le64_to_cpu(data_pool_buf);
+	dout("  data_pool_id = %lld\n", *data_pool_id);
+	WARN_ON(*data_pool_id == CEPH_NOPOOL);
+
 	return 0;
 }
 
@@ -6103,7 +6046,8 @@ out_err:
 	return ret;
 }
 
-static int rbd_dev_v2_snap_context(struct rbd_device *rbd_dev)
+static int rbd_dev_v2_snap_context(struct rbd_device *rbd_dev,
+				   struct ceph_snap_context **psnapc)
 {
 	size_t size;
 	int ret;
@@ -6164,9 +6108,7 @@ static int rbd_dev_v2_snap_context(struct rbd_device *rbd_dev)
 	for (i = 0; i < snap_count; i++)
 		snapc->snaps[i] = ceph_decode_64(&p);
 
-	ceph_put_snap_context(rbd_dev->header.snapc);
-	rbd_dev->header.snapc = snapc;
-
+	*psnapc = snapc;
 	dout("  snap context seq = %llu, snap_count = %u\n",
 		(unsigned long long)seq, (unsigned int)snap_count);
 out:
@@ -6215,38 +6157,42 @@ out:
 	return snap_name;
 }
 
-static int rbd_dev_v2_header_info(struct rbd_device *rbd_dev)
+static int rbd_dev_v2_header_info(struct rbd_device *rbd_dev,
+				  struct rbd_image_header *header,
+				  bool first_time)
 {
-	bool first_time = rbd_dev->header.object_prefix == NULL;
 	int ret;
 
-	ret = rbd_dev_v2_image_size(rbd_dev);
+	ret = _rbd_dev_v2_snap_size(rbd_dev, CEPH_NOSNAP,
+				    first_time ? &header->obj_order : NULL,
+				    &header->image_size);
 	if (ret)
 		return ret;
 
 	if (first_time) {
-		ret = rbd_dev_v2_header_onetime(rbd_dev);
+		ret = rbd_dev_v2_header_onetime(rbd_dev, header);
 		if (ret)
 			return ret;
 	}
 
-	ret = rbd_dev_v2_snap_context(rbd_dev);
-	if (ret && first_time) {
-		kfree(rbd_dev->header.object_prefix);
-		rbd_dev->header.object_prefix = NULL;
-	}
+	ret = rbd_dev_v2_snap_context(rbd_dev, &header->snapc);
+	if (ret)
+		return ret;
 
-	return ret;
+	return 0;
 }
 
-static int rbd_dev_header_info(struct rbd_device *rbd_dev)
+static int rbd_dev_header_info(struct rbd_device *rbd_dev,
+			       struct rbd_image_header *header,
+			       bool first_time)
 {
 	rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
+	rbd_assert(!header->object_prefix && !header->snapc);
 
 	if (rbd_dev->image_format == 1)
-		return rbd_dev_v1_header_info(rbd_dev);
+		return rbd_dev_v1_header_info(rbd_dev, header, first_time);
 
-	return rbd_dev_v2_header_info(rbd_dev);
+	return rbd_dev_v2_header_info(rbd_dev, header, first_time);
 }
 
 /*
@@ -6734,60 +6680,49 @@ out:
  */
 static void rbd_dev_unprobe(struct rbd_device *rbd_dev)
 {
-	struct rbd_image_header	*header;
-
 	rbd_dev_parent_put(rbd_dev);
 	rbd_object_map_free(rbd_dev);
 	rbd_dev_mapping_clear(rbd_dev);
 
 	/* Free dynamic fields from the header, then zero it out */
 
-	header = &rbd_dev->header;
-	ceph_put_snap_context(header->snapc);
-	kfree(header->snap_sizes);
-	kfree(header->snap_names);
-	kfree(header->object_prefix);
-	memset(header, 0, sizeof (*header));
+	rbd_image_header_cleanup(&rbd_dev->header);
 }
 
-static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev)
+static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev,
+				     struct rbd_image_header *header)
 {
 	int ret;
 
-	ret = rbd_dev_v2_object_prefix(rbd_dev);
+	ret = rbd_dev_v2_object_prefix(rbd_dev, &header->object_prefix);
 	if (ret)
-		goto out_err;
+		return ret;
 
 	/*
 	 * Get the and check features for the image.  Currently the
 	 * features are assumed to never change.
 	 */
-	ret = rbd_dev_v2_features(rbd_dev);
+	ret = _rbd_dev_v2_snap_features(rbd_dev, CEPH_NOSNAP,
+					rbd_is_ro(rbd_dev), &header->features);
 	if (ret)
-		goto out_err;
+		return ret;
 
 	/* If the image supports fancy striping, get its parameters */
 
-	if (rbd_dev->header.features & RBD_FEATURE_STRIPINGV2) {
-		ret = rbd_dev_v2_striping_info(rbd_dev);
-		if (ret < 0)
-			goto out_err;
+	if (header->features & RBD_FEATURE_STRIPINGV2) {
+		ret = rbd_dev_v2_striping_info(rbd_dev, &header->stripe_unit,
+					       &header->stripe_count);
+		if (ret)
+			return ret;
 	}
 
-	if (rbd_dev->header.features & RBD_FEATURE_DATA_POOL) {
-		ret = rbd_dev_v2_data_pool(rbd_dev);
+	if (header->features & RBD_FEATURE_DATA_POOL) {
+		ret = rbd_dev_v2_data_pool(rbd_dev, &header->data_pool_id);
 		if (ret)
-			goto out_err;
+			return ret;
 	}
 
-	rbd_init_layout(rbd_dev);
 	return 0;
-
-out_err:
-	rbd_dev->header.features = 0;
-	kfree(rbd_dev->header.object_prefix);
-	rbd_dev->header.object_prefix = NULL;
-	return ret;
 }
 
 /*
@@ -6982,13 +6917,15 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
 	if (!depth)
 		down_write(&rbd_dev->header_rwsem);
 
-	ret = rbd_dev_header_info(rbd_dev);
+	ret = rbd_dev_header_info(rbd_dev, &rbd_dev->header, true);
 	if (ret) {
 		if (ret == -ENOENT && !need_watch)
 			rbd_print_dne(rbd_dev, false);
 		goto err_out_probe;
 	}
 
+	rbd_init_layout(rbd_dev);
+
 	/*
 	 * If this image is the one being mapped, we have pool name and
 	 * id, image name and id, and snap name - need to fill snap id.
@@ -7017,7 +6954,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
 	}
 
 	if (rbd_dev->header.features & RBD_FEATURE_LAYERING) {
-		ret = rbd_dev_v2_parent_info(rbd_dev);
+		ret = rbd_dev_setup_parent(rbd_dev);
 		if (ret)
 			goto err_out_probe;
 	}
@@ -7043,6 +6980,107 @@ err_out_format:
 	return ret;
 }
 
+static void rbd_dev_update_header(struct rbd_device *rbd_dev,
+				  struct rbd_image_header *header)
+{
+	rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
+	rbd_assert(rbd_dev->header.object_prefix); /* !first_time */
+
+	if (rbd_dev->header.image_size != header->image_size) {
+		rbd_dev->header.image_size = header->image_size;
+
+		if (!rbd_is_snap(rbd_dev)) {
+			rbd_dev->mapping.size = header->image_size;
+			rbd_dev_update_size(rbd_dev);
+		}
+	}
+
+	ceph_put_snap_context(rbd_dev->header.snapc);
+	rbd_dev->header.snapc = header->snapc;
+	header->snapc = NULL;
+
+	if (rbd_dev->image_format == 1) {
+		kfree(rbd_dev->header.snap_names);
+		rbd_dev->header.snap_names = header->snap_names;
+		header->snap_names = NULL;
+
+		kfree(rbd_dev->header.snap_sizes);
+		rbd_dev->header.snap_sizes = header->snap_sizes;
+		header->snap_sizes = NULL;
+	}
+}
+
+static void rbd_dev_update_parent(struct rbd_device *rbd_dev,
+				  struct parent_image_info *pii)
+{
+	if (pii->pool_id == CEPH_NOPOOL || !pii->has_overlap) {
+		/*
+		 * Either the parent never existed, or we have
+		 * record of it but the image got flattened so it no
+		 * longer has a parent.  When the parent of a
+		 * layered image disappears we immediately set the
+		 * overlap to 0.  The effect of this is that all new
+		 * requests will be treated as if the image had no
+		 * parent.
+		 *
+		 * If !pii.has_overlap, the parent image spec is not
+		 * applicable.  It's there to avoid duplication in each
+		 * snapshot record.
+		 */
+		if (rbd_dev->parent_overlap) {
+			rbd_dev->parent_overlap = 0;
+			rbd_dev_parent_put(rbd_dev);
+			pr_info("%s: clone has been flattened\n",
+				rbd_dev->disk->disk_name);
+		}
+	} else {
+		rbd_assert(rbd_dev->parent_spec);
+
+		/*
+		 * Update the parent overlap.  If it became zero, issue
+		 * a warning as we will proceed as if there is no parent.
+		 */
+		if (!pii->overlap && rbd_dev->parent_overlap)
+			rbd_warn(rbd_dev,
+				 "clone has become standalone (overlap 0)");
+		rbd_dev->parent_overlap = pii->overlap;
+	}
+}
+
+static int rbd_dev_refresh(struct rbd_device *rbd_dev)
+{
+	struct rbd_image_header	header = { 0 };
+	struct parent_image_info pii = { 0 };
+	int ret;
+
+	dout("%s rbd_dev %p\n", __func__, rbd_dev);
+
+	ret = rbd_dev_header_info(rbd_dev, &header, false);
+	if (ret)
+		goto out;
+
+	/*
+	 * If there is a parent, see if it has disappeared due to the
+	 * mapped image getting flattened.
+	 */
+	if (rbd_dev->parent) {
+		ret = rbd_dev_v2_parent_info(rbd_dev, &pii);
+		if (ret)
+			goto out;
+	}
+
+	down_write(&rbd_dev->header_rwsem);
+	rbd_dev_update_header(rbd_dev, &header);
+	if (rbd_dev->parent)
+		rbd_dev_update_parent(rbd_dev, &pii);
+	up_write(&rbd_dev->header_rwsem);
+
+out:
+	rbd_parent_info_cleanup(&pii);
+	rbd_image_header_cleanup(&header);
+	return ret;
+}
+
 static ssize_t do_rbd_add(const char *buf, size_t count)
 {
 	struct rbd_device *rbd_dev = NULL;