X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=drivers%2Fblock%2Frbd.c;h=f556f8a8b3f9b476949c6133f39778c49502e380;hb=0eefd470f034cc18349fa1a9e4fda000e963c4e3;hp=6c81a4c040b987e75d4a8b0bb5e4ff65e2108dba;hpb=527c680f7c36ff17d49efc99632232dba3549c51;p=karo-tx-linux.git

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 6c81a4c040b9..c34719c917b1 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -52,13 +52,6 @@
 #define	SECTOR_SHIFT	9
 #define	SECTOR_SIZE	(1ULL << SECTOR_SHIFT)
 
-/* It might be useful to have these defined elsewhere */
-
-#define	U8_MAX	((u8)	(~0U))
-#define	U16_MAX	((u16)	(~0U))
-#define	U32_MAX	((u32)	(~0U))
-#define	U64_MAX	((u64)	(~0ULL))
-
 #define RBD_DRV_NAME "rbd"
 #define RBD_DRV_NAME_LONG "rbd (rados block device)"
 
@@ -80,11 +73,14 @@
 
 /* Feature bits */
 
-#define RBD_FEATURE_LAYERING      1
+#define RBD_FEATURE_LAYERING	(1<<0)
+#define RBD_FEATURE_STRIPINGV2	(1<<1)
+#define RBD_FEATURES_ALL \
+	    (RBD_FEATURE_LAYERING | RBD_FEATURE_STRIPINGV2)
 
 /* Features supported by this (client software) implementation. */
 
-#define RBD_FEATURES_ALL          (0)
+#define RBD_FEATURES_SUPPORTED	(0)
 
 /*
  * An RBD device name will be "rbd#", where the "rbd" comes from
@@ -174,13 +170,44 @@ enum obj_request_type {
 	OBJ_REQUEST_NODATA, OBJ_REQUEST_BIO, OBJ_REQUEST_PAGES
 };
 
+enum obj_req_flags {
+	OBJ_REQ_DONE,		/* completion flag: not done = 0, done = 1 */
+	OBJ_REQ_IMG_DATA,	/* object usage: standalone = 0, image = 1 */
+	OBJ_REQ_KNOWN,		/* EXISTS flag valid: no = 0, yes = 1 */
+	OBJ_REQ_EXISTS,		/* target exists: no = 0, yes = 1 */
+};
+
 struct rbd_obj_request {
 	const char		*object_name;
 	u64			offset;		/* object start byte */
 	u64			length;		/* bytes from offset */
+	unsigned long		flags;
 
-	struct rbd_img_request	*img_request;
-	struct list_head	links;		/* img_request->obj_requests */
+	/*
+	 * An object request associated with an image will have its
+	 * img_data flag set; a standalone object request will not.
+	 *
+	 * A standalone object request will have which == BAD_WHICH
+	 * and a null obj_request pointer.
+	 *
+	 * An object request initiated in support of a layered image
+	 * object (to check for its existence before a write) will
+	 * have which == BAD_WHICH and a non-null obj_request pointer.
+	 *
+	 * Finally, an object request for rbd image data will have
+	 * which != BAD_WHICH, and will have a non-null img_request
+	 * pointer.  The value of which will be in the range
+	 * 0..(img_request->obj_request_count-1).
+	 */
+	union {
+		struct rbd_obj_request	*obj_request;	/* STAT op */
+		struct {
+			struct rbd_img_request	*img_request;
+			u64			img_offset;
+			/* links for img_request->obj_requests list */
+			struct list_head	links;
+		};
+	};
 	u32			which;		/* posn image request list */
 
 	enum obj_request_type	type;
@@ -191,13 +218,13 @@ struct rbd_obj_request {
 			u32		page_count;
 		};
 	};
+	struct page		**copyup_pages;
 
 	struct ceph_osd_request	*osd_req;
 
 	u64			xferred;	/* bytes transferred */
 	u64			version;
 	int			result;
-	atomic_t		done;
 
 	rbd_obj_callback_t	callback;
 	struct completion	completion;
@@ -205,19 +232,31 @@ struct rbd_obj_request {
 	struct kref		kref;
 };
 
+enum img_req_flags {
+	IMG_REQ_WRITE,		/* I/O direction: read = 0, write = 1 */
+	IMG_REQ_CHILD,		/* initiator: block = 0, child image = 1 */
+	IMG_REQ_LAYERED,	/* ENOENT handling: normal = 0, layered = 1 */
+};
+
 struct rbd_img_request {
-	struct request		*rq;
 	struct rbd_device	*rbd_dev;
 	u64			offset;	/* starting image byte offset */
 	u64			length;	/* byte count from offset */
-	bool			write_request;	/* false for read */
+	unsigned long		flags;
 	union {
+		u64			snap_id;	/* for reads */
 		struct ceph_snap_context *snapc;	/* for writes */
-		u64		snap_id;		/* for reads */
 	};
+	union {
+		struct request		*rq;		/* block request */
+		struct rbd_obj_request	*obj_request;	/* obj req initiator */
+	};
+	struct page		**copyup_pages;
 	spinlock_t		completion_lock;/* protects next_completion */
 	u32			next_completion;
 	rbd_img_callback_t	callback;
+	u64			xferred;/* aggregate bytes transferred */
+	int			result;	/* first nonzero obj_request result */
 
 	u32			obj_request_count;
 	struct list_head	obj_requests;	/* rbd_obj_request structs */
@@ -276,6 +315,7 @@ struct rbd_device {
 
 	struct rbd_spec		*parent_spec;
 	u64			parent_overlap;
+	struct rbd_device	*parent;
 
 	/* protects updating the header */
 	struct rw_semaphore     header_rwsem;
@@ -312,6 +352,8 @@ static DEFINE_SPINLOCK(rbd_dev_list_lock);
 static LIST_HEAD(rbd_client_list);		/* clients */
 static DEFINE_SPINLOCK(rbd_client_list_lock);
 
+static int rbd_img_request_submit(struct rbd_img_request *img_request);
+
 static int rbd_dev_snaps_update(struct rbd_device *rbd_dev);
 static int rbd_dev_snaps_register(struct rbd_device *rbd_dev);
 
@@ -322,6 +364,7 @@ static ssize_t rbd_add(struct bus_type *bus, const char *buf,
 		       size_t count);
 static ssize_t rbd_remove(struct bus_type *bus, const char *buf,
 			  size_t count);
+static int rbd_dev_probe(struct rbd_device *rbd_dev);
 
 static struct bus_attribute rbd_bus_attrs[] = {
 	__ATTR(add, S_IWUSR, NULL, rbd_add),
@@ -383,6 +426,9 @@ void rbd_warn(struct rbd_device *rbd_dev, const char *fmt, ...)
 #  define rbd_assert(expr)	((void) 0)
 #endif /* !RBD_DEBUG */
 
+static void rbd_img_parent_read(struct rbd_obj_request *obj_request);
+static int rbd_img_obj_request_submit(struct rbd_obj_request *obj_request);
+
 static int rbd_dev_refresh(struct rbd_device *rbd_dev, u64 *hver);
 static int rbd_dev_v2_refresh(struct rbd_device *rbd_dev, u64 *hver);
 
@@ -484,6 +530,13 @@ out_opt:
 	return ERR_PTR(ret);
 }
 
+static struct rbd_client *__rbd_get_client(struct rbd_client *rbdc)
+{
+	kref_get(&rbdc->kref);
+
+	return rbdc;
+}
+
 /*
  * Find a ceph client with specific addr and configuration.  If
  * found, bump its reference count.
@@ -499,7 +552,8 @@ static struct rbd_client *rbd_client_find(struct ceph_options *ceph_opts)
 	spin_lock(&rbd_client_list_lock);
 	list_for_each_entry(client_node, &rbd_client_list, node) {
 		if (!ceph_compare_options(ceph_opts, client_node->client)) {
-			kref_get(&client_node->kref);
+			__rbd_get_client(client_node);
+
 			found = true;
 			break;
 		}
@@ -920,6 +974,37 @@ static void zero_bio_chain(struct bio *chain, int start_ofs)
 	}
 }
 
+/*
+ * similar to zero_bio_chain(), zeros data defined by a page array,
+ * starting at the given byte offset from the start of the array and
+ * continuing up to the given end offset.  The pages array is
+ * assumed to be big enough to hold all bytes up to the end.
+ */
+static void zero_pages(struct page **pages, u64 offset, u64 end)
+{
+	struct page **page = &pages[offset >> PAGE_SHIFT];
+
+	rbd_assert(end > offset);
+	rbd_assert(end - offset <= (u64)SIZE_MAX);
+	while (offset < end) {
+		size_t page_offset;
+		size_t length;
+		unsigned long flags;
+		void *kaddr;
+
+		page_offset = (size_t)(offset & ~PAGE_MASK);
+		length = min(PAGE_SIZE - page_offset, (size_t)(end - offset));
+		local_irq_save(flags);
+		kaddr = kmap_atomic(*page);
+		memset(kaddr + page_offset, 0, length);
+		kunmap_atomic(kaddr);
+		local_irq_restore(flags);
+
+		offset += length;
+		page++;
+	}
+}
+
 /*
  * Clone a portion of a bio, starting at the given byte offset
  * and continuing for the number of bytes indicated.
@@ -1064,6 +1149,77 @@ out_err:
 	return NULL;
 }
 
+/*
+ * The default/initial value for all object request flags is 0.  For
+ * each flag, once its value is set to 1 it is never reset to 0
+ * again.
+ */
+static void obj_request_img_data_set(struct rbd_obj_request *obj_request)
+{
+	if (test_and_set_bit(OBJ_REQ_IMG_DATA, &obj_request->flags)) {
+		struct rbd_device *rbd_dev;
+
+		rbd_dev = obj_request->img_request->rbd_dev;
+		rbd_warn(rbd_dev, "obj_request %p already marked img_data\n",
+			obj_request);
+	}
+}
+
+static bool obj_request_img_data_test(struct rbd_obj_request *obj_request)
+{
+	smp_mb();
+	return test_bit(OBJ_REQ_IMG_DATA, &obj_request->flags) != 0;
+}
+
+static void obj_request_done_set(struct rbd_obj_request *obj_request)
+{
+	if (test_and_set_bit(OBJ_REQ_DONE, &obj_request->flags)) {
+		struct rbd_device *rbd_dev = NULL;
+
+		if (obj_request_img_data_test(obj_request))
+			rbd_dev = obj_request->img_request->rbd_dev;
+		rbd_warn(rbd_dev, "obj_request %p already marked done\n",
+			obj_request);
+	}
+}
+
+static bool obj_request_done_test(struct rbd_obj_request *obj_request)
+{
+	smp_mb();
+	return test_bit(OBJ_REQ_DONE, &obj_request->flags) != 0;
+}
+
+/*
+ * This sets the KNOWN flag after (possibly) setting the EXISTS
+ * flag.  The latter is set based on the "exists" value provided.
+ *
+ * Note that for our purposes once an object exists it never goes
+ * away again.  It's possible that the response from two existence
+ * checks are separated by the creation of the target object, and
+ * the first ("doesn't exist") response arrives *after* the second
+ * ("does exist").  In that case we ignore the second one.
+ */
+static void obj_request_existence_set(struct rbd_obj_request *obj_request,
+				bool exists)
+{
+	if (exists)
+		set_bit(OBJ_REQ_EXISTS, &obj_request->flags);
+	set_bit(OBJ_REQ_KNOWN, &obj_request->flags);
+	smp_mb();
+}
+
+static bool obj_request_known_test(struct rbd_obj_request *obj_request)
+{
+	smp_mb();
+	return test_bit(OBJ_REQ_KNOWN, &obj_request->flags) != 0;
+}
+
+static bool obj_request_exists_test(struct rbd_obj_request *obj_request)
+{
+	smp_mb();
+	return test_bit(OBJ_REQ_EXISTS, &obj_request->flags) != 0;
+}
+
 static void rbd_obj_request_get(struct rbd_obj_request *obj_request)
 {
 	dout("%s: obj %p (was %d)\n", __func__, obj_request,
@@ -1101,9 +1257,11 @@ static inline void rbd_img_obj_request_add(struct rbd_img_request *img_request,
 {
 	rbd_assert(obj_request->img_request == NULL);
 
-	rbd_obj_request_get(obj_request);
+	/* Image request now owns object's original reference */
 	obj_request->img_request = img_request;
 	obj_request->which = img_request->obj_request_count;
+	rbd_assert(!obj_request_img_data_test(obj_request));
+	obj_request_img_data_set(obj_request);
 	rbd_assert(obj_request->which != BAD_WHICH);
 	img_request->obj_request_count++;
 	list_add_tail(&obj_request->links, &img_request->obj_requests);
@@ -1123,6 +1281,7 @@ static inline void rbd_img_obj_request_del(struct rbd_img_request *img_request,
 	img_request->obj_request_count--;
 	rbd_assert(obj_request->which == img_request->obj_request_count);
 	obj_request->which = BAD_WHICH;
+	rbd_assert(obj_request_img_data_test(obj_request));
 	rbd_assert(obj_request->img_request == img_request);
 	obj_request->img_request = NULL;
 	obj_request->callback = NULL;
@@ -1141,76 +1300,6 @@ static bool obj_request_type_valid(enum obj_request_type type)
 	}
 }
 
-static struct ceph_osd_req_op *rbd_osd_req_op_create(u16 opcode, ...)
-{
-	struct ceph_osd_req_op *op;
-	va_list args;
-	size_t size;
-
-	op = kzalloc(sizeof (*op), GFP_NOIO);
-	if (!op)
-		return NULL;
-	op->op = opcode;
-	va_start(args, opcode);
-	switch (opcode) {
-	case CEPH_OSD_OP_READ:
-	case CEPH_OSD_OP_WRITE:
-		/* rbd_osd_req_op_create(READ, offset, length) */
-		/* rbd_osd_req_op_create(WRITE, offset, length) */
-		op->extent.offset = va_arg(args, u64);
-		op->extent.length = va_arg(args, u64);
-		if (opcode == CEPH_OSD_OP_WRITE)
-			op->payload_len = op->extent.length;
-		break;
-	case CEPH_OSD_OP_STAT:
-		break;
-	case CEPH_OSD_OP_CALL:
-		/* rbd_osd_req_op_create(CALL, class, method, data, datalen) */
-		op->cls.class_name = va_arg(args, char *);
-		size = strlen(op->cls.class_name);
-		rbd_assert(size <= (size_t) U8_MAX);
-		op->cls.class_len = size;
-		op->payload_len = size;
-
-		op->cls.method_name = va_arg(args, char *);
-		size = strlen(op->cls.method_name);
-		rbd_assert(size <= (size_t) U8_MAX);
-		op->cls.method_len = size;
-		op->payload_len += size;
-
-		op->cls.argc = 0;
-		op->cls.indata = va_arg(args, void *);
-		size = va_arg(args, size_t);
-		rbd_assert(size <= (size_t) U32_MAX);
-		op->cls.indata_len = (u32) size;
-		op->payload_len += size;
-		break;
-	case CEPH_OSD_OP_NOTIFY_ACK:
-	case CEPH_OSD_OP_WATCH:
-		/* rbd_osd_req_op_create(NOTIFY_ACK, cookie, version) */
-		/* rbd_osd_req_op_create(WATCH, cookie, version, flag) */
-		op->watch.cookie = va_arg(args, u64);
-		op->watch.ver = va_arg(args, u64);
-		op->watch.ver = cpu_to_le64(op->watch.ver);
-		if (opcode == CEPH_OSD_OP_WATCH && va_arg(args, int))
-			op->watch.flag = (u8) 1;
-		break;
-	default:
-		rbd_warn(NULL, "unsupported opcode %hu\n", opcode);
-		kfree(op);
-		op = NULL;
-		break;
-	}
-	va_end(args);
-
-	return op;
-}
-
-static void rbd_osd_req_op_destroy(struct ceph_osd_req_op *op)
-{
-	kfree(op);
-}
-
 static int rbd_obj_request_submit(struct ceph_osd_client *osdc,
 				struct rbd_obj_request *obj_request)
 {
@@ -1221,7 +1310,24 @@ static int rbd_obj_request_submit(struct ceph_osd_client *osdc,
 
 static void rbd_img_request_complete(struct rbd_img_request *img_request)
 {
+
 	dout("%s: img %p\n", __func__, img_request);
+
+	/*
+	 * If no error occurred, compute the aggregate transfer
+	 * count for the image request.  We could instead use
+	 * atomic64_cmpxchg() to update it as each object request
+	 * completes; not clear which way is better off hand.
+	 */
+	if (!img_request->result) {
+		struct rbd_obj_request *obj_request;
+		u64 xferred = 0;
+
+		for_each_obj_request(img_request, obj_request)
+			xferred += obj_request->xferred;
+		img_request->xferred = xferred;
+	}
+
 	if (img_request->callback)
 		img_request->callback(img_request);
 	else
@@ -1237,31 +1343,79 @@ static int rbd_obj_request_wait(struct rbd_obj_request *obj_request)
 	return wait_for_completion_interruptible(&obj_request->completion);
 }
 
-static void obj_request_done_init(struct rbd_obj_request *obj_request)
+/*
+ * The default/initial value for all image request flags is 0.  Each
+ * is conditionally set to 1 at image request initialization time
+ * and currently never change thereafter.
+ */
+static void img_request_write_set(struct rbd_img_request *img_request)
 {
-	atomic_set(&obj_request->done, 0);
-	smp_wmb();
+	set_bit(IMG_REQ_WRITE, &img_request->flags);
+	smp_mb();
 }
 
-static void obj_request_done_set(struct rbd_obj_request *obj_request)
+static bool img_request_write_test(struct rbd_img_request *img_request)
 {
-	int done;
+	smp_mb();
+	return test_bit(IMG_REQ_WRITE, &img_request->flags) != 0;
+}
 
-	done = atomic_inc_return(&obj_request->done);
-	if (done > 1) {
-		struct rbd_img_request *img_request = obj_request->img_request;
-		struct rbd_device *rbd_dev;
+static void img_request_child_set(struct rbd_img_request *img_request)
+{
+	set_bit(IMG_REQ_CHILD, &img_request->flags);
+	smp_mb();
+}
 
-		rbd_dev = img_request ? img_request->rbd_dev : NULL;
-		rbd_warn(rbd_dev, "obj_request %p was already done\n",
-			obj_request);
-	}
+static bool img_request_child_test(struct rbd_img_request *img_request)
+{
+	smp_mb();
+	return test_bit(IMG_REQ_CHILD, &img_request->flags) != 0;
 }
 
-static bool obj_request_done_test(struct rbd_obj_request *obj_request)
+static void img_request_layered_set(struct rbd_img_request *img_request)
+{
+	set_bit(IMG_REQ_LAYERED, &img_request->flags);
+	smp_mb();
+}
+
+static bool img_request_layered_test(struct rbd_img_request *img_request)
 {
 	smp_mb();
-	return atomic_read(&obj_request->done) != 0;
+	return test_bit(IMG_REQ_LAYERED, &img_request->flags) != 0;
+}
+
+static void
+rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request)
+{
+	u64 xferred = obj_request->xferred;
+	u64 length = obj_request->length;
+
+	dout("%s: obj %p img %p result %d %llu/%llu\n", __func__,
+		obj_request, obj_request->img_request, obj_request->result,
+		xferred, length);
+	/*
+	 * ENOENT means a hole in the image.  We zero-fill the
+	 * entire length of the request.  A short read also implies
+	 * zero-fill to the end of the request.  Either way we
+	 * update the xferred count to indicate the whole request
+	 * was satisfied.
+	 */
+	rbd_assert(obj_request->type != OBJ_REQUEST_NODATA);
+	if (obj_request->result == -ENOENT) {
+		if (obj_request->type == OBJ_REQUEST_BIO)
+			zero_bio_chain(obj_request->bio_list, 0);
+		else
+			zero_pages(obj_request->pages, 0, length);
+		obj_request->result = 0;
+		obj_request->xferred = length;
+	} else if (xferred < length && !obj_request->result) {
+		if (obj_request->type == OBJ_REQUEST_BIO)
+			zero_bio_chain(obj_request->bio_list, xferred);
+		else
+			zero_pages(obj_request->pages, xferred, length);
+		obj_request->xferred = length;
+	}
+	obj_request_done_set(obj_request);
 }
 
 static void rbd_obj_request_complete(struct rbd_obj_request *obj_request)
@@ -1282,25 +1436,26 @@ static void rbd_osd_trivial_callback(struct rbd_obj_request *obj_request)
 
 static void rbd_osd_read_callback(struct rbd_obj_request *obj_request)
 {
-	dout("%s: obj %p result %d %llu/%llu\n", __func__, obj_request,
-		obj_request->result, obj_request->xferred, obj_request->length);
-	/*
-	 * ENOENT means a hole in the object.  We zero-fill the
-	 * entire length of the request.  A short read also implies
-	 * zero-fill to the end of the request.  Either way we
-	 * update the xferred count to indicate the whole request
-	 * was satisfied.
-	 */
-	if (obj_request->result == -ENOENT) {
-		zero_bio_chain(obj_request->bio_list, 0);
-		obj_request->result = 0;
-		obj_request->xferred = obj_request->length;
-	} else if (obj_request->xferred < obj_request->length &&
-			!obj_request->result) {
-		zero_bio_chain(obj_request->bio_list, obj_request->xferred);
-		obj_request->xferred = obj_request->length;
+	struct rbd_img_request *img_request = NULL;
+	bool layered = false;
+
+	if (obj_request_img_data_test(obj_request)) {
+		img_request = obj_request->img_request;
+		layered = img_request && img_request_layered_test(img_request);
+	} else {
+		img_request = NULL;
+		layered = false;
 	}
-	obj_request_done_set(obj_request);
+
+	dout("%s: obj %p img %p result %d %llu/%llu\n", __func__,
+		obj_request, img_request, obj_request->result,
+		obj_request->xferred, obj_request->length);
+	if (layered && obj_request->result == -ENOENT)
+		rbd_img_parent_read(obj_request);
+	else if (img_request)
+		rbd_img_obj_request_read_callback(obj_request);
+	else
+		obj_request_done_set(obj_request);
 }
 
 static void rbd_osd_write_callback(struct rbd_obj_request *obj_request)
@@ -1308,9 +1463,8 @@ static void rbd_osd_write_callback(struct rbd_obj_request *obj_request)
 	dout("%s: obj %p result %d %llu\n", __func__, obj_request,
 		obj_request->result, obj_request->length);
 	/*
-	 * There is no such thing as a successful short write.
-	 * Our xferred value is the number of bytes transferred
-	 * back.  Set it to our originally-requested length.
+	 * There is no such thing as a successful short write.  Set
+	 * it to our originally-requested length.
 	 */
 	obj_request->xferred = obj_request->length;
 	obj_request_done_set(obj_request);
@@ -1334,22 +1488,26 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req,
 
 	dout("%s: osd_req %p msg %p\n", __func__, osd_req, msg);
 	rbd_assert(osd_req == obj_request->osd_req);
-	rbd_assert(!!obj_request->img_request ^
-				(obj_request->which == BAD_WHICH));
+	if (obj_request_img_data_test(obj_request)) {
+		rbd_assert(obj_request->img_request);
+		rbd_assert(obj_request->which != BAD_WHICH);
+	} else {
+		rbd_assert(obj_request->which == BAD_WHICH);
+	}
 
 	if (osd_req->r_result < 0)
 		obj_request->result = osd_req->r_result;
 	obj_request->version = le64_to_cpu(osd_req->r_reassert_version.version);
 
-	WARN_ON(osd_req->r_num_ops != 1);	/* For now */
+	BUG_ON(osd_req->r_num_ops > 2);
 
 	/*
 	 * We support a 64-bit length, but ultimately it has to be
 	 * passed to blk_end_request(), which takes an unsigned int.
 	 */
 	obj_request->xferred = osd_req->r_reply_op_len[0];
-	rbd_assert(obj_request->xferred < (u64) UINT_MAX);
-	opcode = osd_req->r_request_ops[0].op;
+	rbd_assert(obj_request->xferred < (u64)UINT_MAX);
+	opcode = osd_req->r_ops[0].op;
 	switch (opcode) {
 	case CEPH_OSD_OP_READ:
 		rbd_osd_read_callback(obj_request);
@@ -1375,28 +1533,49 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req,
 		rbd_obj_request_complete(obj_request);
 }
 
+static void rbd_osd_req_format_read(struct rbd_obj_request *obj_request)
+{
+	struct rbd_img_request *img_request = obj_request->img_request;
+	struct ceph_osd_request *osd_req = obj_request->osd_req;
+	u64 snap_id;
+
+	rbd_assert(osd_req != NULL);
+
+	snap_id = img_request ? img_request->snap_id : CEPH_NOSNAP;
+	ceph_osdc_build_request(osd_req, obj_request->offset,
+			NULL, snap_id, NULL);
+}
+
+static void rbd_osd_req_format_write(struct rbd_obj_request *obj_request)
+{
+	struct rbd_img_request *img_request = obj_request->img_request;
+	struct ceph_osd_request *osd_req = obj_request->osd_req;
+	struct ceph_snap_context *snapc;
+	struct timespec mtime = CURRENT_TIME;
+
+	rbd_assert(osd_req != NULL);
+
+	snapc = img_request ? img_request->snapc : NULL;
+	ceph_osdc_build_request(osd_req, obj_request->offset,
+			snapc, CEPH_NOSNAP, &mtime);
+}
+
 static struct ceph_osd_request *rbd_osd_req_create(
 					struct rbd_device *rbd_dev,
 					bool write_request,
-					struct rbd_obj_request *obj_request,
-					struct ceph_osd_req_op *op)
+					struct rbd_obj_request *obj_request)
 {
-	struct rbd_img_request *img_request = obj_request->img_request;
 	struct ceph_snap_context *snapc = NULL;
 	struct ceph_osd_client *osdc;
 	struct ceph_osd_request *osd_req;
-	struct timespec now;
-	struct timespec *mtime;
-	u64 snap_id = CEPH_NOSNAP;
-	u64 offset = obj_request->offset;
-	u64 length = obj_request->length;
 
-	if (img_request) {
-		rbd_assert(img_request->write_request == write_request);
-		if (img_request->write_request)
+	if (obj_request_img_data_test(obj_request)) {
+		struct rbd_img_request *img_request = obj_request->img_request;
+
+		rbd_assert(write_request ==
+				img_request_write_test(img_request));
+		if (write_request)
 			snapc = img_request->snapc;
-		else
-			snap_id = img_request->snap_id;
 	}
 
 	/* Allocate and initialize the request, for the single op */
@@ -1406,31 +1585,10 @@ static struct ceph_osd_request *rbd_osd_req_create(
 	if (!osd_req)
 		return NULL;	/* ENOMEM */
 
-	rbd_assert(obj_request_type_valid(obj_request->type));
-	switch (obj_request->type) {
-	case OBJ_REQUEST_NODATA:
-		break;		/* Nothing to do */
-	case OBJ_REQUEST_BIO:
-		rbd_assert(obj_request->bio_list != NULL);
-		osd_req->r_bio = obj_request->bio_list;
-		break;
-	case OBJ_REQUEST_PAGES:
-		osd_req->r_pages = obj_request->pages;
-		osd_req->r_num_pages = obj_request->page_count;
-		osd_req->r_page_alignment = offset & ~PAGE_MASK;
-		break;
-	}
-
-	if (write_request) {
+	if (write_request)
 		osd_req->r_flags = CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK;
-		now = CURRENT_TIME;
-		mtime = &now;
-	} else {
+	else
 		osd_req->r_flags = CEPH_OSD_FLAG_READ;
-		mtime = NULL;	/* not needed for reads */
-		offset = 0;	/* These are not used... */
-		length = 0;	/* ...for osd read requests */
-	}
 
 	osd_req->r_callback = rbd_osd_req_callback;
 	osd_req->r_priv = obj_request;
@@ -1441,14 +1599,51 @@ static struct ceph_osd_request *rbd_osd_req_create(
 
 	osd_req->r_file_layout = rbd_dev->layout;	/* struct */
 
-	/* osd_req will get its own reference to snapc (if non-null) */
+	return osd_req;
+}
 
-	ceph_osdc_build_request(osd_req, offset, length, 1, op,
-				snapc, snap_id, mtime);
+/*
+ * Create a copyup osd request based on the information in the
+ * object request supplied.  A copyup request has two osd ops,
+ * a copyup method call, and a "normal" write request.
+ */
+static struct ceph_osd_request *
+rbd_osd_req_create_copyup(struct rbd_obj_request *obj_request)
+{
+	struct rbd_img_request *img_request;
+	struct ceph_snap_context *snapc;
+	struct rbd_device *rbd_dev;
+	struct ceph_osd_client *osdc;
+	struct ceph_osd_request *osd_req;
+
+	rbd_assert(obj_request_img_data_test(obj_request));
+	img_request = obj_request->img_request;
+	rbd_assert(img_request);
+	rbd_assert(img_request_write_test(img_request));
+
+	/* Allocate and initialize the request, for the two ops */
+
+	snapc = img_request->snapc;
+	rbd_dev = img_request->rbd_dev;
+	osdc = &rbd_dev->rbd_client->client->osdc;
+	osd_req = ceph_osdc_alloc_request(osdc, snapc, 2, false, GFP_ATOMIC);
+	if (!osd_req)
+		return NULL;	/* ENOMEM */
+
+	osd_req->r_flags = CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK;
+	osd_req->r_callback = rbd_osd_req_callback;
+	osd_req->r_priv = obj_request;
+
+	osd_req->r_oid_len = strlen(obj_request->object_name);
+	rbd_assert(osd_req->r_oid_len < sizeof (osd_req->r_oid));
+	memcpy(osd_req->r_oid, obj_request->object_name, osd_req->r_oid_len);
+
+	osd_req->r_file_layout = rbd_dev->layout;	/* struct */
 
 	return osd_req;
 }
 
+
 static void rbd_osd_req_destroy(struct ceph_osd_request *osd_req)
 {
 	ceph_osdc_put_request(osd_req);
@@ -1475,10 +1670,10 @@ static struct rbd_obj_request *rbd_obj_request_create(const char *object_name,
 	obj_request->object_name = memcpy(name, object_name, size);
 	obj_request->offset = offset;
 	obj_request->length = length;
+	obj_request->flags = 0;
 	obj_request->which = BAD_WHICH;
 	obj_request->type = type;
 	INIT_LIST_HEAD(&obj_request->links);
-	obj_request_done_init(obj_request);
 	init_completion(&obj_request->completion);
 	kref_init(&obj_request->kref);
 
@@ -1528,7 +1723,8 @@ static void rbd_obj_request_destroy(struct kref *kref)
 static struct rbd_img_request *rbd_img_request_create(
 					struct rbd_device *rbd_dev,
 					u64 offset, u64 length,
-					bool write_request)
+					bool write_request,
+					bool child_request)
 {
 	struct rbd_img_request *img_request;
 	struct ceph_snap_context *snapc = NULL;
@@ -1545,216 +1741,712 @@ static struct rbd_img_request *rbd_img_request_create(
 			kfree(img_request);
 			return NULL;	/* Shouldn't happen */
 		}
+
 	}
 
 	img_request->rq = NULL;
 	img_request->rbd_dev = rbd_dev;
 	img_request->offset = offset;
 	img_request->length = length;
-	img_request->write_request = write_request;
-	if (write_request)
+	img_request->flags = 0;
+	if (write_request) {
+		img_request_write_set(img_request);
 		img_request->snapc = snapc;
-	else
+	} else {
 		img_request->snap_id = rbd_dev->spec->snap_id;
+	}
+	if (child_request)
+		img_request_child_set(img_request);
+	if (rbd_dev->parent_spec)
+		img_request_layered_set(img_request);
 	spin_lock_init(&img_request->completion_lock);
 	img_request->next_completion = 0;
 	img_request->callback = NULL;
+	img_request->result = 0;
 	img_request->obj_request_count = 0;
 	INIT_LIST_HEAD(&img_request->obj_requests);
 	kref_init(&img_request->kref);
 
-	rbd_img_request_get(img_request);	/* Avoid a warning */
-	rbd_img_request_put(img_request);	/* TEMPORARY */
+	rbd_img_request_get(img_request);	/* Avoid a warning */
+	rbd_img_request_put(img_request);	/* TEMPORARY */
+
+	dout("%s: rbd_dev %p %s %llu/%llu -> img %p\n", __func__, rbd_dev,
+		write_request ? "write" : "read", offset, length,
+		img_request);
+
+	return img_request;
+}
+
+static void rbd_img_request_destroy(struct kref *kref)
+{
+	struct rbd_img_request *img_request;
+	struct rbd_obj_request *obj_request;
+	struct rbd_obj_request *next_obj_request;
+
+	img_request = container_of(kref, struct rbd_img_request, kref);
+
+	dout("%s: img %p\n", __func__, img_request);
+
+	for_each_obj_request_safe(img_request, obj_request, next_obj_request)
+		rbd_img_obj_request_del(img_request, obj_request);
+	rbd_assert(img_request->obj_request_count == 0);
+
+	if (img_request_write_test(img_request))
+		ceph_put_snap_context(img_request->snapc);
+
+	if (img_request_child_test(img_request))
+		rbd_obj_request_put(img_request->obj_request);
+
+	kfree(img_request);
+}
+
+static bool rbd_img_obj_end_request(struct rbd_obj_request *obj_request)
+{
+	struct rbd_img_request *img_request;
+	unsigned int xferred;
+	int result;
+	bool more;
+
+	rbd_assert(obj_request_img_data_test(obj_request));
+	img_request = obj_request->img_request;
+
+	rbd_assert(obj_request->xferred <= (u64)UINT_MAX);
+	xferred = (unsigned int)obj_request->xferred;
+	result = obj_request->result;
+	if (result) {
+		struct rbd_device *rbd_dev = img_request->rbd_dev;
+
+		rbd_warn(rbd_dev, "%s %llx at %llx (%llx)\n",
+			img_request_write_test(img_request) ? "write" : "read",
+			obj_request->length, obj_request->img_offset,
+			obj_request->offset);
+		rbd_warn(rbd_dev, "  result %d xferred %x\n",
+			result, xferred);
+		if (!img_request->result)
+			img_request->result = result;
+	}
+
+	/* Image object requests don't own their page array */
+
+	if (obj_request->type == OBJ_REQUEST_PAGES) {
+		obj_request->pages = NULL;
+		obj_request->page_count = 0;
+	}
+
+	if (img_request_child_test(img_request)) {
+		rbd_assert(img_request->obj_request != NULL);
+		more = obj_request->which < img_request->obj_request_count - 1;
+	} else {
+		rbd_assert(img_request->rq != NULL);
+		more = blk_end_request(img_request->rq, result, xferred);
+	}
+
+	return more;
+}
+
+static void rbd_img_obj_callback(struct rbd_obj_request *obj_request)
+{
+	struct rbd_img_request *img_request;
+	u32 which = obj_request->which;
+	bool more = true;
+
+	rbd_assert(obj_request_img_data_test(obj_request));
+	img_request = obj_request->img_request;
+
+	dout("%s: img %p obj %p\n", __func__, img_request, obj_request);
+	rbd_assert(img_request != NULL);
+	rbd_assert(img_request->obj_request_count > 0);
+	rbd_assert(which != BAD_WHICH);
+	rbd_assert(which < img_request->obj_request_count);
+	rbd_assert(which >= img_request->next_completion);
+
+	spin_lock_irq(&img_request->completion_lock);
+	if (which != img_request->next_completion)
+		goto out;
+
+	for_each_obj_request_from(img_request, obj_request) {
+		rbd_assert(more);
+		rbd_assert(which < img_request->obj_request_count);
+
+		if (!obj_request_done_test(obj_request))
+			break;
+		more = rbd_img_obj_end_request(obj_request);
+		which++;
+	}
+
+	rbd_assert(more ^ (which == img_request->obj_request_count));
+	img_request->next_completion = which;
+out:
+	spin_unlock_irq(&img_request->completion_lock);
+
+	if (!more)
+		rbd_img_request_complete(img_request);
+}
+
+/*
+ * Split up an image request into one or more object requests, each
+ * to a different object.  The "type" parameter indicates whether
+ * "data_desc" is the pointer to the head of a list of bio
+ * structures, or the base of a page array.  In either case this
+ * function assumes data_desc describes memory sufficient to hold
+ * all data described by the image request.
+ */
+static int rbd_img_request_fill(struct rbd_img_request *img_request,
+					enum obj_request_type type,
+					void *data_desc)
+{
+	struct rbd_device *rbd_dev = img_request->rbd_dev;
+	struct rbd_obj_request *obj_request = NULL;
+	struct rbd_obj_request *next_obj_request;
+	bool write_request = img_request_write_test(img_request);
+	struct bio *bio_list;
+	unsigned int bio_offset = 0;
+	struct page **pages;
+	u64 img_offset;
+	u64 resid;
+	u16 opcode;
+
+	dout("%s: img %p type %d data_desc %p\n", __func__, img_request,
+		(int)type, data_desc);
+
+	opcode = write_request ? CEPH_OSD_OP_WRITE : CEPH_OSD_OP_READ;
+	img_offset = img_request->offset;
+	resid = img_request->length;
+	rbd_assert(resid > 0);
+
+	if (type == OBJ_REQUEST_BIO) {
+		bio_list = data_desc;
+		rbd_assert(img_offset == bio_list->bi_sector << SECTOR_SHIFT);
+	} else {
+		rbd_assert(type == OBJ_REQUEST_PAGES);
+		pages = data_desc;
+	}
+
+	while (resid) {
+		struct ceph_osd_request *osd_req;
+		const char *object_name;
+		u64 offset;
+		u64 length;
+
+		object_name = rbd_segment_name(rbd_dev, img_offset);
+		if (!object_name)
+			goto out_unwind;
+		offset = rbd_segment_offset(rbd_dev, img_offset);
+		length = rbd_segment_length(rbd_dev, img_offset, resid);
+		obj_request = rbd_obj_request_create(object_name,
+						offset, length, type);
+		kfree(object_name);	/* object request has its own copy */
+		if (!obj_request)
+			goto out_unwind;
+
+		if (type == OBJ_REQUEST_BIO) {
+			unsigned int clone_size;
+
+			rbd_assert(length <= (u64)UINT_MAX);
+			clone_size = (unsigned int)length;
+			obj_request->bio_list =
+					bio_chain_clone_range(&bio_list,
+								&bio_offset,
+								clone_size,
+								GFP_ATOMIC);
+			if (!obj_request->bio_list)
+				goto out_partial;
+		} else {
+			unsigned int page_count;
+
+			obj_request->pages = pages;
+			page_count = (u32)calc_pages_for(offset, length);
+			obj_request->page_count = page_count;
+			if ((offset + length) & ~PAGE_MASK)
+				page_count--;	/* more on last page */
+			pages += page_count;
+		}
+
+		osd_req = rbd_osd_req_create(rbd_dev, write_request,
+						obj_request);
+		if (!osd_req)
+			goto out_partial;
+		obj_request->osd_req = osd_req;
+		obj_request->callback = rbd_img_obj_callback;
+
+		osd_req_op_extent_init(osd_req, 0, opcode, offset, length,
+						0, 0);
+		if (type == OBJ_REQUEST_BIO)
+			osd_req_op_extent_osd_data_bio(osd_req, 0,
+					obj_request->bio_list, length);
+		else
+			osd_req_op_extent_osd_data_pages(osd_req, 0,
+					obj_request->pages, length,
+					offset & ~PAGE_MASK, false, false);
+
+		if (write_request)
+			rbd_osd_req_format_write(obj_request);
+		else
+			rbd_osd_req_format_read(obj_request);
+
+		obj_request->img_offset = img_offset;
+		rbd_img_obj_request_add(img_request, obj_request);
+
+		img_offset += length;
+		resid -= length;
+	}
+
+	return 0;
+
+out_partial:
+	rbd_obj_request_put(obj_request);
+out_unwind:
+	for_each_obj_request_safe(img_request, obj_request, next_obj_request)
+		rbd_obj_request_put(obj_request);
+
+	return -ENOMEM;
+}
+
+static void
+rbd_img_obj_copyup_callback(struct rbd_obj_request *obj_request)
+{
+	struct rbd_img_request *img_request;
+	struct rbd_device *rbd_dev;
+	u64 length;
+	u32 page_count;
+
+	rbd_assert(obj_request->type == OBJ_REQUEST_BIO);
+	rbd_assert(obj_request_img_data_test(obj_request));
+	img_request = obj_request->img_request;
+	rbd_assert(img_request);
+
+	rbd_dev = img_request->rbd_dev;
+	rbd_assert(rbd_dev);
+	length = (u64)1 << rbd_dev->header.obj_order;
+	page_count = (u32)calc_pages_for(0, length);
+
+	rbd_assert(obj_request->copyup_pages);
+	ceph_release_page_vector(obj_request->copyup_pages, page_count);
+	obj_request->copyup_pages = NULL;
+
+	/*
+	 * We want the transfer count to reflect the size of the
+	 * original write request.  There is no such thing as a
+	 * successful short write, so if the request was successful
+	 * we can just set it to the originally-requested length.
+	 */
+	if (!obj_request->result)
+		obj_request->xferred = obj_request->length;
+
+	/* Finish up with the normal image object callback */
+
+	rbd_img_obj_callback(obj_request);
+}
+
+static void
+rbd_img_obj_parent_read_full_callback(struct rbd_img_request *img_request)
+{
+	struct rbd_obj_request *orig_request;
+	struct ceph_osd_request *osd_req;
+	struct ceph_osd_client *osdc;
+	struct rbd_device *rbd_dev;
+	struct page **pages;
+	int result;
+	u64 obj_size;
+	u64 xferred;
+
+	rbd_assert(img_request_child_test(img_request));
+
+	/* First get what we need from the image request */
+
+	pages = img_request->copyup_pages;
+	rbd_assert(pages != NULL);
+	img_request->copyup_pages = NULL;
+
+	orig_request = img_request->obj_request;
+	rbd_assert(orig_request != NULL);
+	rbd_assert(orig_request->type == OBJ_REQUEST_BIO);
+	result = img_request->result;
+	obj_size = img_request->length;
+	xferred = img_request->xferred;
+
+	rbd_dev = img_request->rbd_dev;
+	rbd_assert(rbd_dev);
+	rbd_assert(obj_size == (u64)1 << rbd_dev->header.obj_order);
+
+	rbd_img_request_put(img_request);
+
+	if (result)
+		goto out_err;
+
+	/* Allocate the new copyup osd request for the original request */
 
-	dout("%s: rbd_dev %p %s %llu/%llu -> img %p\n", __func__, rbd_dev,
-		write_request ? "write" : "read", offset, length,
-		img_request);
+	result = -ENOMEM;
+	rbd_assert(!orig_request->osd_req);
+	osd_req = rbd_osd_req_create_copyup(orig_request);
+	if (!osd_req)
+		goto out_err;
+	orig_request->osd_req = osd_req;
+	orig_request->copyup_pages = pages;
 
-	return img_request;
-}
+	/* Initialize the copyup op */
 
-static void rbd_img_request_destroy(struct kref *kref)
-{
-	struct rbd_img_request *img_request;
-	struct rbd_obj_request *obj_request;
-	struct rbd_obj_request *next_obj_request;
+	osd_req_op_cls_init(osd_req, 0, CEPH_OSD_OP_CALL, "rbd", "copyup");
+	osd_req_op_cls_request_data_pages(osd_req, 0, pages, obj_size, 0,
+						false, false);
 
-	img_request = container_of(kref, struct rbd_img_request, kref);
+	/* Then the original write request op */
 
-	dout("%s: img %p\n", __func__, img_request);
+	osd_req_op_extent_init(osd_req, 1, CEPH_OSD_OP_WRITE,
+					orig_request->offset,
+					orig_request->length, 0, 0);
+	osd_req_op_extent_osd_data_bio(osd_req, 1, orig_request->bio_list,
+					orig_request->length);
 
-	for_each_obj_request_safe(img_request, obj_request, next_obj_request)
-		rbd_img_obj_request_del(img_request, obj_request);
-	rbd_assert(img_request->obj_request_count == 0);
+	rbd_osd_req_format_write(orig_request);
 
-	if (img_request->write_request)
-		ceph_put_snap_context(img_request->snapc);
+	/* All set, send it off. */
 
-	kfree(img_request);
+	orig_request->callback = rbd_img_obj_copyup_callback;
+	osdc = &rbd_dev->rbd_client->client->osdc;
+	result = rbd_obj_request_submit(osdc, orig_request);
+	if (!result)
+		return;
+out_err:
+	/* Record the error code and complete the request */
+
+	orig_request->result = result;
+	orig_request->xferred = 0;
+	obj_request_done_set(orig_request);
+	rbd_obj_request_complete(orig_request);
 }
 
-static int rbd_img_request_fill_bio(struct rbd_img_request *img_request,
-					struct bio *bio_list)
+/*
+ * Read from the parent image the range of data that covers the
+ * entire target of the given object request.  This is used for
+ * satisfying a layered image write request when the target of an
+ * object request from the image request does not exist.
+ *
+ * A page array big enough to hold the returned data is allocated
+ * and supplied to rbd_img_request_fill() as the "data descriptor."
+ * When the read completes, this page array will be transferred to
+ * the original object request for the copyup operation.
+ *
+ * If an error occurs, record it as the result of the original
+ * object request and mark it done so it gets completed.
+ */
+static int rbd_img_obj_parent_read_full(struct rbd_obj_request *obj_request)
 {
-	struct rbd_device *rbd_dev = img_request->rbd_dev;
-	struct rbd_obj_request *obj_request = NULL;
-	struct rbd_obj_request *next_obj_request;
-	unsigned int bio_offset;
-	u64 image_offset;
-	u64 resid;
-	u16 opcode;
+	struct rbd_img_request *img_request = NULL;
+	struct rbd_img_request *parent_request = NULL;
+	struct rbd_device *rbd_dev;
+	u64 img_offset;
+	u64 length;
+	struct page **pages = NULL;
+	u32 page_count;
+	int result;
 
-	dout("%s: img %p bio %p\n", __func__, img_request, bio_list);
+	rbd_assert(obj_request_img_data_test(obj_request));
+	rbd_assert(obj_request->type == OBJ_REQUEST_BIO);
 
-	opcode = img_request->write_request ? CEPH_OSD_OP_WRITE
-					      : CEPH_OSD_OP_READ;
-	bio_offset = 0;
-	image_offset = img_request->offset;
-	rbd_assert(image_offset == bio_list->bi_sector << SECTOR_SHIFT);
-	resid = img_request->length;
-	rbd_assert(resid > 0);
-	while (resid) {
-		const char *object_name;
-		unsigned int clone_size;
-		struct ceph_osd_req_op *op;
-		u64 offset;
-		u64 length;
+	img_request = obj_request->img_request;
+	rbd_assert(img_request != NULL);
+	rbd_dev = img_request->rbd_dev;
+	rbd_assert(rbd_dev->parent != NULL);
 
-		object_name = rbd_segment_name(rbd_dev, image_offset);
-		if (!object_name)
-			goto out_unwind;
-		offset = rbd_segment_offset(rbd_dev, image_offset);
-		length = rbd_segment_length(rbd_dev, image_offset, resid);
-		obj_request = rbd_obj_request_create(object_name,
-						offset, length,
-						OBJ_REQUEST_BIO);
-		kfree(object_name);	/* object request has its own copy */
-		if (!obj_request)
-			goto out_unwind;
+	/*
+	 * First things first.  The original osd request is of no
+	 * use to use any more, we'll need a new one that can hold
+	 * the two ops in a copyup request.  We'll get that later,
+	 * but for now we can release the old one.
+	 */
+	rbd_osd_req_destroy(obj_request->osd_req);
+	obj_request->osd_req = NULL;
 
-		rbd_assert(length <= (u64) UINT_MAX);
-		clone_size = (unsigned int) length;
-		obj_request->bio_list = bio_chain_clone_range(&bio_list,
-						&bio_offset, clone_size,
-						GFP_ATOMIC);
-		if (!obj_request->bio_list)
-			goto out_partial;
+	/*
+	 * Determine the byte range covered by the object in the
+	 * child image to which the original request was to be sent.
+	 */
+	img_offset = obj_request->img_offset - obj_request->offset;
+	length = (u64)1 << rbd_dev->header.obj_order;
 
-		/*
-		 * Build up the op to use in building the osd
-		 * request.  Note that the contents of the op are
-		 * copied by rbd_osd_req_create().
-		 */
-		op = rbd_osd_req_op_create(opcode, offset, length);
-		if (!op)
-			goto out_partial;
-		obj_request->osd_req = rbd_osd_req_create(rbd_dev,
-						img_request->write_request,
-						obj_request, op);
-		rbd_osd_req_op_destroy(op);
-		if (!obj_request->osd_req)
-			goto out_partial;
-		/* status and version are initially zero-filled */
+	/*
+	 * Allocate a page array big enough to receive the data read
+	 * from the parent.
+	 */
+	page_count = (u32)calc_pages_for(0, length);
+	pages = ceph_alloc_page_vector(page_count, GFP_KERNEL);
+	if (IS_ERR(pages)) {
+		result = PTR_ERR(pages);
+		pages = NULL;
+		goto out_err;
+	}
 
-		rbd_img_obj_request_add(img_request, obj_request);
+	result = -ENOMEM;
+	parent_request = rbd_img_request_create(rbd_dev->parent,
+						img_offset, length,
+						false, true);
+	if (!parent_request)
+		goto out_err;
+	rbd_obj_request_get(obj_request);
+	parent_request->obj_request = obj_request;
 
-		image_offset += length;
-		resid -= length;
-	}
+	result = rbd_img_request_fill(parent_request, OBJ_REQUEST_PAGES, pages);
+	if (result)
+		goto out_err;
+	parent_request->copyup_pages = pages;
 
-	return 0;
+	parent_request->callback = rbd_img_obj_parent_read_full_callback;
+	result = rbd_img_request_submit(parent_request);
+	if (!result)
+		return 0;
 
-out_partial:
+	parent_request->copyup_pages = NULL;
+	parent_request->obj_request = NULL;
 	rbd_obj_request_put(obj_request);
-out_unwind:
-	for_each_obj_request_safe(img_request, obj_request, next_obj_request)
-		rbd_obj_request_put(obj_request);
+out_err:
+	if (pages)
+		ceph_release_page_vector(pages, page_count);
+	if (parent_request)
+		rbd_img_request_put(parent_request);
+	obj_request->result = result;
+	obj_request->xferred = 0;
+	obj_request_done_set(obj_request);
 
-	return -ENOMEM;
+	return result;
 }
 
-static void rbd_img_obj_callback(struct rbd_obj_request *obj_request)
+static void rbd_img_obj_exists_callback(struct rbd_obj_request *obj_request)
 {
-	struct rbd_img_request *img_request;
-	u32 which = obj_request->which;
-	bool more = true;
+	struct rbd_obj_request *orig_request;
+	int result;
 
-	img_request = obj_request->img_request;
+	rbd_assert(!obj_request_img_data_test(obj_request));
 
-	dout("%s: img %p obj %p\n", __func__, img_request, obj_request);
-	rbd_assert(img_request != NULL);
-	rbd_assert(img_request->rq != NULL);
-	rbd_assert(img_request->obj_request_count > 0);
-	rbd_assert(which != BAD_WHICH);
-	rbd_assert(which < img_request->obj_request_count);
-	rbd_assert(which >= img_request->next_completion);
+	/*
+	 * All we need from the object request is the original
+	 * request and the result of the STAT op.  Grab those, then
+	 * we're done with the request.
+	 */
+	orig_request = obj_request->obj_request;
+	obj_request->obj_request = NULL;
+	rbd_assert(orig_request);
+	rbd_assert(orig_request->img_request);
 
-	spin_lock_irq(&img_request->completion_lock);
-	if (which != img_request->next_completion)
+	result = obj_request->result;
+	obj_request->result = 0;
+
+	dout("%s: obj %p for obj %p result %d %llu/%llu\n", __func__,
+		obj_request, orig_request, result,
+		obj_request->xferred, obj_request->length);
+	rbd_obj_request_put(obj_request);
+
+	rbd_assert(orig_request);
+	rbd_assert(orig_request->img_request);
+
+	/*
+	 * Our only purpose here is to determine whether the object
+	 * exists, and we don't want to treat the non-existence as
+	 * an error.  If something else comes back, transfer the
+	 * error to the original request and complete it now.
+	 */
+	if (!result) {
+		obj_request_existence_set(orig_request, true);
+	} else if (result == -ENOENT) {
+		obj_request_existence_set(orig_request, false);
+	} else if (result) {
+		orig_request->result = result;
 		goto out;
+	}
 
-	for_each_obj_request_from(img_request, obj_request) {
-		unsigned int xferred;
-		int result;
+	/*
+	 * Resubmit the original request now that we have recorded
+	 * whether the target object exists.
+	 */
+	orig_request->result = rbd_img_obj_request_submit(orig_request);
+out:
+	if (orig_request->result)
+		rbd_obj_request_complete(orig_request);
+	rbd_obj_request_put(orig_request);
+}
 
-		rbd_assert(more);
-		rbd_assert(which < img_request->obj_request_count);
+static int rbd_img_obj_exists_submit(struct rbd_obj_request *obj_request)
+{
+	struct rbd_obj_request *stat_request;
+	struct rbd_device *rbd_dev;
+	struct ceph_osd_client *osdc;
+	struct page **pages = NULL;
+	u32 page_count;
+	size_t size;
+	int ret;
 
-		if (!obj_request_done_test(obj_request))
-			break;
+	/*
+	 * The response data for a STAT call consists of:
+	 *     le64 length;
+	 *     struct {
+	 *         le32 tv_sec;
+	 *         le32 tv_nsec;
+	 *     } mtime;
+	 */
+	size = sizeof (__le64) + sizeof (__le32) + sizeof (__le32);
+	page_count = (u32)calc_pages_for(0, size);
+	pages = ceph_alloc_page_vector(page_count, GFP_KERNEL);
+	if (IS_ERR(pages))
+		return PTR_ERR(pages);
 
-		rbd_assert(obj_request->xferred <= (u64) UINT_MAX);
-		xferred = (unsigned int) obj_request->xferred;
-		result = (int) obj_request->result;
-		if (result)
-			rbd_warn(NULL, "obj_request %s result %d xferred %u\n",
-				img_request->write_request ? "write" : "read",
-				result, xferred);
+	ret = -ENOMEM;
+	stat_request = rbd_obj_request_create(obj_request->object_name, 0, 0,
+							OBJ_REQUEST_PAGES);
+	if (!stat_request)
+		goto out;
 
-		more = blk_end_request(img_request->rq, result, xferred);
-		which++;
-	}
+	rbd_obj_request_get(obj_request);
+	stat_request->obj_request = obj_request;
+	stat_request->pages = pages;
+	stat_request->page_count = page_count;
+
+	rbd_assert(obj_request->img_request);
+	rbd_dev = obj_request->img_request->rbd_dev;
+	stat_request->osd_req = rbd_osd_req_create(rbd_dev, false,
+						stat_request);
+	if (!stat_request->osd_req)
+		goto out;
+	stat_request->callback = rbd_img_obj_exists_callback;
 
-	rbd_assert(more ^ (which == img_request->obj_request_count));
-	img_request->next_completion = which;
+	osd_req_op_init(stat_request->osd_req, 0, CEPH_OSD_OP_STAT);
+	osd_req_op_raw_data_in_pages(stat_request->osd_req, 0, pages, size, 0,
+					false, false);
+	rbd_osd_req_format_read(stat_request);
+
+	osdc = &rbd_dev->rbd_client->client->osdc;
+	ret = rbd_obj_request_submit(osdc, stat_request);
 out:
-	spin_unlock_irq(&img_request->completion_lock);
+	if (ret)
+		rbd_obj_request_put(obj_request);
 
-	if (!more)
-		rbd_img_request_complete(img_request);
+	return ret;
+}
+
+static int rbd_img_obj_request_submit(struct rbd_obj_request *obj_request)
+{
+	struct rbd_img_request *img_request;
+	bool known;
+
+	rbd_assert(obj_request_img_data_test(obj_request));
+
+	img_request = obj_request->img_request;
+	rbd_assert(img_request);
+
+	/*
+	 * Only layered writes need special handling.  If it's not a
+	 * layered write, or it is a layered write but we know the
+	 * target object exists, it's no different from any other
+	 * object request.
+	 */
+	if (!img_request_write_test(img_request) ||
+		!img_request_layered_test(img_request) ||
+		((known = obj_request_known_test(obj_request)) &&
+			obj_request_exists_test(obj_request))) {
+
+		struct rbd_device *rbd_dev;
+		struct ceph_osd_client *osdc;
+
+		rbd_dev = obj_request->img_request->rbd_dev;
+		osdc = &rbd_dev->rbd_client->client->osdc;
+
+		return rbd_obj_request_submit(osdc, obj_request);
+	}
+
+	/*
+	 * It's a layered write.  The target object might exist but
+	 * we may not know that yet.  If we know it doesn't exist,
+	 * start by reading the data for the full target object from
+	 * the parent so we can use it for a copyup to the target.
+	 */
+	if (known)
+		return rbd_img_obj_parent_read_full(obj_request);
+
+	/* We don't know whether the target exists.  Go find out. */
+
+	return rbd_img_obj_exists_submit(obj_request);
 }
 
 static int rbd_img_request_submit(struct rbd_img_request *img_request)
 {
-	struct rbd_device *rbd_dev = img_request->rbd_dev;
-	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
 	struct rbd_obj_request *obj_request;
+	struct rbd_obj_request *next_obj_request;
 
 	dout("%s: img %p\n", __func__, img_request);
-	for_each_obj_request(img_request, obj_request) {
+	for_each_obj_request_safe(img_request, obj_request, next_obj_request) {
 		int ret;
 
-		obj_request->callback = rbd_img_obj_callback;
-		ret = rbd_obj_request_submit(osdc, obj_request);
+		ret = rbd_img_obj_request_submit(obj_request);
 		if (ret)
 			return ret;
-		/*
-		 * The image request has its own reference to each
-		 * of its object requests, so we can safely drop the
-		 * initial one here.
-		 */
-		rbd_obj_request_put(obj_request);
 	}
 
 	return 0;
 }
 
+static void rbd_img_parent_read_callback(struct rbd_img_request *img_request)
+{
+	struct rbd_obj_request *obj_request;
+
+	rbd_assert(img_request_child_test(img_request));
+
+	obj_request = img_request->obj_request;
+	rbd_assert(obj_request != NULL);
+	obj_request->result = img_request->result;
+	obj_request->xferred = img_request->xferred;
+
+	rbd_img_obj_request_read_callback(obj_request);
+	rbd_obj_request_complete(obj_request);
+}
+
+static void rbd_img_parent_read(struct rbd_obj_request *obj_request)
+{
+	struct rbd_device *rbd_dev;
+	struct rbd_img_request *img_request;
+	int result;
+
+	rbd_assert(obj_request_img_data_test(obj_request));
+	rbd_assert(obj_request->img_request != NULL);
+	rbd_assert(obj_request->result == (s32) -ENOENT);
+	rbd_assert(obj_request->type == OBJ_REQUEST_BIO);
+
+	rbd_dev = obj_request->img_request->rbd_dev;
+	rbd_assert(rbd_dev->parent != NULL);
+	/* rbd_read_finish(obj_request, obj_request->length); */
+	img_request = rbd_img_request_create(rbd_dev->parent,
+						obj_request->img_offset,
+						obj_request->length,
+						false, true);
+	result = -ENOMEM;
+	if (!img_request)
+		goto out_err;
+
+	rbd_obj_request_get(obj_request);
+	img_request->obj_request = obj_request;
+
+	result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO,
+					obj_request->bio_list);
+	if (result)
+		goto out_err;
+
+	img_request->callback = rbd_img_parent_read_callback;
+	result = rbd_img_request_submit(img_request);
+	if (result)
+		goto out_err;
+
+	return;
+out_err:
+	if (img_request)
+		rbd_img_request_put(img_request);
+	obj_request->result = result;
+	obj_request->xferred = 0;
+	obj_request_done_set(obj_request);
+}
+
 static int rbd_obj_notify_ack(struct rbd_device *rbd_dev,
 				   u64 ver, u64 notify_id)
 {
 	struct rbd_obj_request *obj_request;
-	struct ceph_osd_req_op *op;
-	struct ceph_osd_client *osdc;
+	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
 	int ret;
 
 	obj_request = rbd_obj_request_create(rbd_dev->header_name, 0, 0,
@@ -1763,17 +2455,15 @@ static int rbd_obj_notify_ack(struct rbd_device *rbd_dev,
 		return -ENOMEM;
 
 	ret = -ENOMEM;
-	op = rbd_osd_req_op_create(CEPH_OSD_OP_NOTIFY_ACK, notify_id, ver);
-	if (!op)
-		goto out;
-	obj_request->osd_req = rbd_osd_req_create(rbd_dev, false,
-						obj_request, op);
-	rbd_osd_req_op_destroy(op);
+	obj_request->osd_req = rbd_osd_req_create(rbd_dev, false, obj_request);
 	if (!obj_request->osd_req)
 		goto out;
-
-	osdc = &rbd_dev->rbd_client->client->osdc;
 	obj_request->callback = rbd_obj_request_put;
+
+	osd_req_op_watch_init(obj_request->osd_req, 0, CEPH_OSD_OP_NOTIFY_ACK,
+					notify_id, ver, 0);
+	rbd_osd_req_format_read(obj_request);
+
 	ret = rbd_obj_request_submit(osdc, obj_request);
 out:
 	if (ret)
@@ -1810,7 +2500,6 @@ static int rbd_dev_header_watch_sync(struct rbd_device *rbd_dev, int start)
 {
 	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
 	struct rbd_obj_request *obj_request;
-	struct ceph_osd_req_op *op;
 	int ret;
 
 	rbd_assert(start ^ !!rbd_dev->watch_event);
@@ -1830,14 +2519,7 @@ static int rbd_dev_header_watch_sync(struct rbd_device *rbd_dev, int start)
 	if (!obj_request)
 		goto out_cancel;
 
-	op = rbd_osd_req_op_create(CEPH_OSD_OP_WATCH,
-				rbd_dev->watch_event->cookie,
-				rbd_dev->header.obj_version, start);
-	if (!op)
-		goto out_cancel;
-	obj_request->osd_req = rbd_osd_req_create(rbd_dev, true,
-							obj_request, op);
-	rbd_osd_req_op_destroy(op);
+	obj_request->osd_req = rbd_osd_req_create(rbd_dev, true, obj_request);
 	if (!obj_request->osd_req)
 		goto out_cancel;
 
@@ -1846,6 +2528,12 @@ static int rbd_dev_header_watch_sync(struct rbd_device *rbd_dev, int start)
 	else
 		ceph_osdc_unregister_linger_request(osdc,
 					rbd_dev->watch_request->osd_req);
+
+	osd_req_op_watch_init(obj_request->osd_req, 0, CEPH_OSD_OP_WATCH,
+				rbd_dev->watch_event->cookie,
+				rbd_dev->header.obj_version, start);
+	rbd_osd_req_format_write(obj_request);
+
 	ret = rbd_obj_request_submit(osdc, obj_request);
 	if (ret)
 		goto out_cancel;
@@ -1897,20 +2585,18 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
 			     size_t inbound_size,
 			     u64 *version)
 {
+	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
 	struct rbd_obj_request *obj_request;
-	struct ceph_osd_client *osdc;
-	struct ceph_osd_req_op *op;
 	struct page **pages;
 	u32 page_count;
 	int ret;
 
 	/*
-	 * Method calls are ultimately read operations but they
-	 * don't involve object data (so no offset or length).
-	 * The result should placed into the inbound buffer
-	 * provided.  They also supply outbound data--parameters for
-	 * the object method.  Currently if this is present it will
-	 * be a snapshot id.
+	 * Method calls are ultimately read operations.  The result
+	 * should placed into the inbound buffer provided.  They
+	 * also supply outbound data--parameters for the object
+	 * method.  Currently if this is present it will be a
+	 * snapshot id.
 	 */
 	page_count = (u32) calc_pages_for(0, inbound_size);
 	pages = ceph_alloc_page_vector(page_count, GFP_KERNEL);
@@ -1918,7 +2604,7 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
 		return PTR_ERR(pages);
 
 	ret = -ENOMEM;
-	obj_request = rbd_obj_request_create(object_name, 0, 0,
+	obj_request = rbd_obj_request_create(object_name, 0, inbound_size,
 							OBJ_REQUEST_PAGES);
 	if (!obj_request)
 		goto out;
@@ -1926,17 +2612,29 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
 	obj_request->pages = pages;
 	obj_request->page_count = page_count;
 
-	op = rbd_osd_req_op_create(CEPH_OSD_OP_CALL, class_name,
-					method_name, outbound, outbound_size);
-	if (!op)
-		goto out;
-	obj_request->osd_req = rbd_osd_req_create(rbd_dev, false,
-						obj_request, op);
-	rbd_osd_req_op_destroy(op);
+	obj_request->osd_req = rbd_osd_req_create(rbd_dev, false, obj_request);
 	if (!obj_request->osd_req)
 		goto out;
 
-	osdc = &rbd_dev->rbd_client->client->osdc;
+	osd_req_op_cls_init(obj_request->osd_req, 0, CEPH_OSD_OP_CALL,
+					class_name, method_name);
+	if (outbound_size) {
+		struct ceph_pagelist *pagelist;
+
+		pagelist = kmalloc(sizeof (*pagelist), GFP_NOFS);
+		if (!pagelist)
+			goto out;
+
+		ceph_pagelist_init(pagelist);
+		ceph_pagelist_append(pagelist, outbound, outbound_size);
+		osd_req_op_cls_request_data_pagelist(obj_request->osd_req, 0,
+						pagelist);
+	}
+	osd_req_op_cls_response_data_pages(obj_request->osd_req, 0,
+					obj_request->pages, inbound_size,
+					0, false, false);
+	rbd_osd_req_format_read(obj_request);
+
 	ret = rbd_obj_request_submit(osdc, obj_request);
 	if (ret)
 		goto out;
@@ -2025,13 +2723,14 @@ static void rbd_request_fn(struct request_queue *q)
 
 		result = -ENOMEM;
 		img_request = rbd_img_request_create(rbd_dev, offset, length,
-							write_request);
+							write_request, false);
 		if (!img_request)
 			goto end_request;
 
 		img_request->rq = rq;
 
-		result = rbd_img_request_fill_bio(img_request, rq->bio);
+		result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO,
+						rq->bio);
 		if (!result)
 			result = rbd_img_request_submit(img_request);
 		if (result)
@@ -2039,8 +2738,10 @@ static void rbd_request_fn(struct request_queue *q)
 end_request:
 		spin_lock_irq(q->queue_lock);
 		if (result < 0) {
-			rbd_warn(rbd_dev, "obj_request %s result %d\n",
-				write_request ? "write" : "read", result);
+			rbd_warn(rbd_dev, "%s %llx at %llx result %d\n",
+				write_request ? "write" : "read",
+				length, offset, result);
+
 			__blk_end_request_all(rq, result);
 		}
 	}
@@ -2112,9 +2813,8 @@ static int rbd_obj_read_sync(struct rbd_device *rbd_dev,
 				char *buf, u64 *version)
 
 {
-	struct ceph_osd_req_op *op;
+	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
 	struct rbd_obj_request *obj_request;
-	struct ceph_osd_client *osdc;
 	struct page **pages = NULL;
 	u32 page_count;
 	size_t size;
@@ -2134,16 +2834,19 @@ static int rbd_obj_read_sync(struct rbd_device *rbd_dev,
 	obj_request->pages = pages;
 	obj_request->page_count = page_count;
 
-	op = rbd_osd_req_op_create(CEPH_OSD_OP_READ, offset, length);
-	if (!op)
-		goto out;
-	obj_request->osd_req = rbd_osd_req_create(rbd_dev, false,
-						obj_request, op);
-	rbd_osd_req_op_destroy(op);
+	obj_request->osd_req = rbd_osd_req_create(rbd_dev, false, obj_request);
 	if (!obj_request->osd_req)
 		goto out;
 
-	osdc = &rbd_dev->rbd_client->client->osdc;
+	osd_req_op_extent_init(obj_request->osd_req, 0, CEPH_OSD_OP_READ,
+					offset, length, 0, 0);
+	osd_req_op_extent_osd_data_pages(obj_request->osd_req, 0,
+					obj_request->pages,
+					obj_request->length,
+					obj_request->offset & ~PAGE_MASK,
+					false, false);
+	rbd_osd_req_format_read(obj_request);
+
 	ret = rbd_obj_request_submit(osdc, obj_request);
 	if (ret)
 		goto out;
@@ -2337,6 +3040,7 @@ static int rbd_dev_refresh(struct rbd_device *rbd_dev, u64 *hver)
 	else
 		ret = rbd_dev_v2_refresh(rbd_dev, hver);
 	mutex_unlock(&ctl_mutex);
+	revalidate_disk(rbd_dev->disk);
 
 	return ret;
 }
@@ -2680,8 +3384,6 @@ static struct rbd_spec *rbd_spec_alloc(void)
 		return NULL;
 	kref_init(&spec->kref);
 
-	rbd_spec_put(rbd_spec_get(spec));	/* TEMPORARY */
-
 	return spec;
 }
 
@@ -2913,7 +3615,7 @@ static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
 		return ret;
 
 	incompat = le64_to_cpu(features_buf.incompat);
-	if (incompat & ~RBD_FEATURES_ALL)
+	if (incompat & ~RBD_FEATURES_SUPPORTED)
 		return -ENXIO;
 
 	*snap_features = le64_to_cpu(features_buf.features);
@@ -3776,6 +4478,11 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
 	void *response;
 	void *p;
 
+	/* If we already have it we don't need to look it up */
+
+	if (rbd_dev->spec->image_id)
+		return 0;
+
 	/*
 	 * When probing a parent image, the image id is already
 	 * known (and the image name likely is not).  There's no
@@ -3953,6 +4660,9 @@ out_err:
 
 static int rbd_dev_probe_finish(struct rbd_device *rbd_dev)
 {
+	struct rbd_device *parent = NULL;
+	struct rbd_spec *parent_spec = NULL;
+	struct rbd_client *rbdc = NULL;
 	int ret;
 
 	/* no need to lock here, as rbd_dev is not registered yet */
@@ -3997,6 +4707,31 @@ static int rbd_dev_probe_finish(struct rbd_device *rbd_dev)
 	 * At this point cleanup in the event of an error is the job
 	 * of the sysfs code (initiated by rbd_bus_del_dev()).
 	 */
+	/* Probe the parent if there is one */
+
+	if (rbd_dev->parent_spec) {
+		/*
+		 * We need to pass a reference to the client and the
+		 * parent spec when creating the parent rbd_dev.
+		 * Images related by parent/child relationships
+		 * always share both.
+		 */
+		parent_spec = rbd_spec_get(rbd_dev->parent_spec);
+		rbdc = __rbd_get_client(rbd_dev->rbd_client);
+
+		parent = rbd_dev_create(rbdc, parent_spec);
+		if (!parent) {
+			ret = -ENOMEM;
+			goto err_out_spec;
+		}
+		rbdc = NULL;		/* parent now owns reference */
+		parent_spec = NULL;	/* parent now owns reference */
+		ret = rbd_dev_probe(parent);
+		if (ret < 0)
+			goto err_out_parent;
+		rbd_dev->parent = parent;
+	}
+
 	down_write(&rbd_dev->header_rwsem);
 	ret = rbd_dev_snaps_register(rbd_dev);
 	up_write(&rbd_dev->header_rwsem);
@@ -4015,6 +4750,12 @@ static int rbd_dev_probe_finish(struct rbd_device *rbd_dev)
 		(unsigned long long) rbd_dev->mapping.size);
 
 	return ret;
+
+err_out_parent:
+	rbd_dev_destroy(parent);
+err_out_spec:
+	rbd_spec_put(parent_spec);
+	rbd_put_client(rbdc);
 err_out_bus:
 	/* this will also clean up rest of rbd_dev stuff */
 
@@ -4178,6 +4919,12 @@ static void rbd_dev_release(struct device *dev)
 	module_put(THIS_MODULE);
 }
 
+static void __rbd_remove(struct rbd_device *rbd_dev)
+{
+	rbd_remove_all_snaps(rbd_dev);
+	rbd_bus_del_dev(rbd_dev);
+}
+
 static ssize_t rbd_remove(struct bus_type *bus,
 			  const char *buf,
 			  size_t count)
@@ -4213,8 +4960,26 @@ static ssize_t rbd_remove(struct bus_type *bus,
 	if (ret < 0)
 		goto done;
 
-	rbd_remove_all_snaps(rbd_dev);
-	rbd_bus_del_dev(rbd_dev);
+	while (rbd_dev->parent_spec) {
+		struct rbd_device *first = rbd_dev;
+		struct rbd_device *second = first->parent;
+		struct rbd_device *third;
+
+		/*
+		 * Follow to the parent with no grandparent and
+		 * remove it.
+		 */
+		while (second && (third = second->parent)) {
+			first = second;
+			second = third;
+		}
+		__rbd_remove(second);
+		rbd_spec_put(first->parent_spec);
+		first->parent_spec = NULL;
+		first->parent_overlap = 0;
+		first->parent = NULL;
+	}
+	__rbd_remove(rbd_dev);
 
 done:
 	mutex_unlock(&ctl_mutex);