rbd: remove old request handling code

Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

drivers/block/rbd.c

@@ -231,8 +231,6 @@ enum obj_operation_type {
 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 */
 };
 
 /*
@@ -271,27 +269,15 @@ struct rbd_obj_request {
 	 * 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;
@@ -480,8 +466,6 @@ static bool single_major = true;
 module_param(single_major, bool, S_IRUGO);
 MODULE_PARM_DESC(single_major, "Use a single major number for all rbd devices (default: true)");
 
-static int rbd_img_request_submit(struct rbd_img_request *img_request);
-
 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,
@@ -610,9 +594,6 @@ void rbd_warn(struct rbd_device *rbd_dev, const char *fmt, ...)
 #  define rbd_assert(expr)	((void) 0)
 #endif /* !RBD_DEBUG */
 
-static void rbd_osd_copyup_callback(struct rbd_obj_request *obj_request);
-static int rbd_img_obj_request_submit(struct rbd_obj_request *obj_request);
-static void rbd_img_parent_read(struct rbd_obj_request *obj_request);
 static void rbd_dev_remove_parent(struct rbd_device *rbd_dev);
 
 static int rbd_dev_refresh(struct rbd_device *rbd_dev);
@@ -1369,37 +1350,6 @@ static bool obj_request_done_test(struct rbd_obj_request *obj_request)
 	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 bool obj_request_overlaps_parent(struct rbd_obj_request *obj_request)
 {
 	struct rbd_device *rbd_dev = obj_request->img_request->rbd_dev;
@@ -1643,42 +1593,6 @@ static bool rbd_img_is_write(struct rbd_img_request *img_req)
 	}
 }
 
-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.  An error requires the whole
-	 * length of the request to be reported finished with an error
-	 * to the block layer.  In each case 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_bios(&obj_request->bio_pos, 0, length);
-		else
-			zero_bvecs(&obj_request->bvec_pos, 0, length);
-		obj_request->result = 0;
-	} else if (xferred < length && !obj_request->result) {
-		if (obj_request->type == OBJ_REQUEST_BIO)
-			zero_bios(&obj_request->bio_pos, xferred,
-				  length - xferred);
-		else
-			zero_bvecs(&obj_request->bvec_pos, xferred,
-				   length - xferred);
-	}
-	obj_request->xferred = length;
-	obj_request_done_set(obj_request);
-}
-
 static void rbd_obj_request_complete(struct rbd_obj_request *obj_request)
 {
 	dout("%s: obj %p cb %p\n", __func__, obj_request,
@@ -1686,93 +1600,6 @@ static void rbd_obj_request_complete(struct rbd_obj_request *obj_request)
 	obj_request->callback(obj_request);
 }
 
-static void rbd_obj_request_error(struct rbd_obj_request *obj_request, int err)
-{
-	obj_request->result = err;
-	obj_request->xferred = 0;
-	/*
-	 * kludge - mirror rbd_obj_request_submit() to match a put in
-	 * rbd_img_obj_callback()
-	 */
-	if (obj_request_img_data_test(obj_request)) {
-		WARN_ON(obj_request->callback != rbd_img_obj_callback);
-		rbd_img_request_get(obj_request->img_request);
-	}
-	obj_request_done_set(obj_request);
-	rbd_obj_request_complete(obj_request);
-}
-
-static void rbd_osd_read_callback(struct rbd_obj_request *obj_request)
-{
-	struct rbd_img_request *img_request = NULL;
-	struct rbd_device *rbd_dev = 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);
-		rbd_dev = img_request->rbd_dev;
-	}
-
-	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 &&
-			obj_request->img_offset < rbd_dev->parent_overlap)
-		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)
-{
-	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.  Set
-	 * it to our originally-requested length.
-	 */
-	obj_request->xferred = obj_request->length;
-	obj_request_done_set(obj_request);
-}
-
-static void rbd_osd_discard_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 discard.  Set
-	 * it to our originally-requested length.
-	 */
-	obj_request->xferred = obj_request->length;
-	/* discarding a non-existent object is not a problem */
-	if (obj_request->result == -ENOENT)
-		obj_request->result = 0;
-	obj_request_done_set(obj_request);
-}
-
-/*
- * For a simple stat call there's nothing to do.  We'll do more if
- * this is part of a write sequence for a layered image.
- */
-static void rbd_osd_stat_callback(struct rbd_obj_request *obj_request)
-{
-	dout("%s: obj %p\n", __func__, obj_request);
-	obj_request_done_set(obj_request);
-}
-
-static void rbd_osd_call_callback(struct rbd_obj_request *obj_request)
-{
-	dout("%s: obj %p\n", __func__, obj_request);
-
-	if (obj_request_img_data_test(obj_request))
-		rbd_osd_copyup_callback(obj_request);
-	else
-		obj_request_done_set(obj_request);
-}
-
 static void rbd_obj_handle_request(struct rbd_obj_request *obj_req);
 
 static void rbd_osd_req_callback(struct ceph_osd_request *osd_req)
@@ -1871,32 +1698,6 @@ static struct ceph_osd_request *rbd_osd_req_create(
 	    CEPH_OSD_FLAG_WRITE : CEPH_OSD_FLAG_READ, obj_request);
 }
 
-/*
- * Create a copyup osd request based on the information in the object
- * request supplied.  A copyup request has two or three osd ops, a
- * copyup method call, potentially a hint op, and a write or truncate
- * or zero op.
- */
-static struct ceph_osd_request *
-rbd_osd_req_create_copyup(struct rbd_obj_request *obj_request)
-{
-	struct rbd_img_request *img_request;
-	int num_osd_ops = 3;
-
-	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) ||
-			img_request_discard_test(img_request));
-
-	if (img_request_discard_test(img_request))
-		num_osd_ops = 2;
-
-	return __rbd_osd_req_create(img_request->rbd_dev,
-				    img_request->snapc, num_osd_ops,
-				    CEPH_OSD_FLAG_WRITE, obj_request);
-}
-
 static void rbd_osd_req_destroy(struct ceph_osd_request *osd_req)
 {
 	ceph_osdc_put_request(osd_req);
@@ -2217,73 +2018,6 @@ static void rbd_img_obj_callback(struct rbd_obj_request *obj_request)
 		rbd_img_request_complete(img_request);
 }
 
-/*
- * Add individual osd ops to the given ceph_osd_request and prepare
- * them for submission. num_ops is the current number of
- * osd operations already to the object request.
- */
-static void rbd_img_obj_request_fill(struct rbd_obj_request *obj_request,
-				struct ceph_osd_request *osd_request,
-				enum obj_operation_type op_type,
-				unsigned int num_ops)
-{
-	struct rbd_img_request *img_request = obj_request->img_request;
-	struct rbd_device *rbd_dev = img_request->rbd_dev;
-	u64 object_size = rbd_obj_bytes(&rbd_dev->header);
-	u64 offset = obj_request->offset;
-	u64 length = obj_request->length;
-	u64 img_end;
-	u16 opcode;
-
-	if (op_type == OBJ_OP_DISCARD) {
-		if (!offset && length == object_size &&
-		    (!img_request_layered_test(img_request) ||
-		     !obj_request_overlaps_parent(obj_request))) {
-			opcode = CEPH_OSD_OP_DELETE;
-		} else if ((offset + length == object_size)) {
-			opcode = CEPH_OSD_OP_TRUNCATE;
-		} else {
-			down_read(&rbd_dev->header_rwsem);
-			img_end = rbd_dev->header.image_size;
-			up_read(&rbd_dev->header_rwsem);
-
-			if (obj_request->img_offset + length == img_end)
-				opcode = CEPH_OSD_OP_TRUNCATE;
-			else
-				opcode = CEPH_OSD_OP_ZERO;
-		}
-	} else if (op_type == OBJ_OP_WRITE) {
-		if (!offset && length == object_size)
-			opcode = CEPH_OSD_OP_WRITEFULL;
-		else
-			opcode = CEPH_OSD_OP_WRITE;
-		osd_req_op_alloc_hint_init(osd_request, num_ops,
-					object_size, object_size);
-		num_ops++;
-	} else {
-		opcode = CEPH_OSD_OP_READ;
-	}
-
-	if (opcode == CEPH_OSD_OP_DELETE)
-		osd_req_op_init(osd_request, num_ops, opcode, 0);
-	else
-		osd_req_op_extent_init(osd_request, num_ops, opcode,
-				       offset, length, 0, 0);
-
-	if (obj_request->type == OBJ_REQUEST_BIO)
-		osd_req_op_extent_osd_data_bio(osd_request, num_ops,
-					&obj_request->bio_pos, length);
-	else if (obj_request->type == OBJ_REQUEST_BVECS)
-		osd_req_op_extent_osd_data_bvec_pos(osd_request, num_ops,
-					&obj_request->bvec_pos);
-
-	/* Discards are also writes */
-	if (op_type == OBJ_OP_WRITE || op_type == OBJ_OP_DISCARD)
-		rbd_osd_req_format_write(obj_request);
-	else
-		rbd_osd_req_format_read(obj_request);
-}
-
 static void rbd_osd_req_setup_data(struct rbd_obj_request *obj_req, u32 which)
 {
 	switch (obj_req->type) {
@@ -2568,366 +2302,6 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
 	return -ENOMEM;
 }
 
-static void
-rbd_osd_copyup_callback(struct rbd_obj_request *obj_request)
-{
-	struct rbd_img_request *img_request;
-	struct rbd_device *rbd_dev;
-
-	dout("%s: obj %p\n", __func__, obj_request);
-
-	rbd_assert(obj_request->type == OBJ_REQUEST_BIO ||
-		obj_request->type == OBJ_REQUEST_NODATA);
-	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);
-
-	/*
-	 * 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;
-
-	obj_request_done_set(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 rbd_device *rbd_dev;
-	enum obj_operation_type op_type;
-	int img_result;
-	u64 parent_length;
-
-	rbd_assert(img_request_child_test(img_request));
-
-	/* First get what we need from the image request */
-
-	orig_request = img_request->obj_request;
-	rbd_assert(orig_request != NULL);
-	rbd_assert(obj_request_type_valid(orig_request->type));
-	img_result = img_request->result;
-	parent_length = img_request->length;
-	rbd_assert(img_result || parent_length == img_request->xferred);
-	rbd_img_request_put(img_request);
-
-	rbd_assert(orig_request->img_request);
-	rbd_dev = orig_request->img_request->rbd_dev;
-	rbd_assert(rbd_dev);
-
-	/*
-	 * If the overlap has become 0 (most likely because the
-	 * image has been flattened) we need to free the pages
-	 * and re-submit the original write request.
-	 */
-	if (!rbd_dev->parent_overlap) {
-		rbd_obj_request_submit(orig_request);
-		return;
-	}
-
-	if (img_result)
-		goto out_err;
-
-	/*
-	 * The original osd request is of no use to use any more.
-	 * We need a new one that can hold the three ops in a copyup
-	 * request.  Allocate the new copyup osd request for the
-	 * original request, and release the old one.
-	 */
-	img_result = -ENOMEM;
-	osd_req = rbd_osd_req_create_copyup(orig_request);
-	if (!osd_req)
-		goto out_err;
-	rbd_osd_req_destroy(orig_request->osd_req);
-	orig_request->osd_req = osd_req;
-
-	/* Initialize the copyup op */
-
-	osd_req_op_cls_init(osd_req, 0, CEPH_OSD_OP_CALL, "rbd", "copyup");
-	osd_req_op_cls_request_data_bvecs(osd_req, 0, orig_request->copyup_bvecs,
-					  parent_length);
-
-	/* Add the other op(s) */
-
-	op_type = rbd_img_request_op_type(orig_request->img_request);
-	rbd_img_obj_request_fill(orig_request, osd_req, op_type, 1);
-
-	/* All set, send it off. */
-
-	rbd_obj_request_submit(orig_request);
-	return;
-
-out_err:
-	rbd_obj_request_error(orig_request, img_result);
-}
-
-static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap);
-
-/*
- * 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, it is recorded as the result of the original
- * object request in rbd_img_obj_exists_callback().
- */
-static int rbd_img_obj_parent_read_full(struct rbd_obj_request *obj_request)
-{
-	struct rbd_device *rbd_dev = obj_request->img_request->rbd_dev;
-	struct rbd_img_request *parent_request = NULL;
-	struct ceph_bvec_iter bvec_it = { 0 };
-	u64 img_offset;
-	u64 length;
-	int result;
-
-	rbd_assert(rbd_dev->parent != NULL);
-
-	/*
-	 * 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 = rbd_obj_bytes(&rbd_dev->header);
-
-	/*
-	 * There is no defined parent data beyond the parent
-	 * overlap, so limit what we read at that boundary if
-	 * necessary.
-	 */
-	if (img_offset + length > rbd_dev->parent_overlap) {
-		rbd_assert(img_offset < rbd_dev->parent_overlap);
-		length = rbd_dev->parent_overlap - img_offset;
-	}
-
-	/*
-	 * Allocate a page array big enough to receive the data read
-	 * from the parent.
-	 */
-	result = setup_copyup_bvecs(obj_request, length);
-	if (result)
-		goto out_err;
-
-	result = -ENOMEM;
-	parent_request = rbd_parent_request_create(obj_request,
-						img_offset, length);
-	if (!parent_request)
-		goto out_err;
-
-	bvec_it.bvecs = obj_request->copyup_bvecs;
-	bvec_it.iter.bi_size = length;
-	result = rbd_img_request_fill(parent_request, OBJ_REQUEST_BVECS,
-				      &bvec_it);
-	if (result)
-		goto out_err;
-
-	parent_request->callback = rbd_img_obj_parent_read_full_callback;
-
-	result = rbd_img_request_submit(parent_request);
-	if (!result)
-		return 0;
-
-out_err:
-	if (parent_request)
-		rbd_img_request_put(parent_request);
-	return result;
-}
-
-static void rbd_img_obj_exists_callback(struct rbd_obj_request *obj_request)
-{
-	struct rbd_obj_request *orig_request;
-	struct rbd_device *rbd_dev;
-	int result;
-
-	rbd_assert(!obj_request_img_data_test(obj_request));
-
-	/*
-	 * 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_obj_request_put(orig_request);
-	rbd_assert(orig_request);
-	rbd_assert(orig_request->img_request);
-
-	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);
-
-	/*
-	 * If the overlap has become 0 (most likely because the
-	 * image has been flattened) we need to re-submit the
-	 * original request.
-	 */
-	rbd_dev = orig_request->img_request->rbd_dev;
-	if (!rbd_dev->parent_overlap) {
-		rbd_obj_request_submit(orig_request);
-		return;
-	}
-
-	/*
-	 * 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 {
-		goto fail_orig_request;
-	}
-
-	/*
-	 * Resubmit the original request now that we have recorded
-	 * whether the target object exists.
-	 */
-	result = rbd_img_obj_request_submit(orig_request);
-	if (result)
-		goto fail_orig_request;
-
-	return;
-
-fail_orig_request:
-	rbd_obj_request_error(orig_request, result);
-}
-
-static int rbd_img_obj_exists_submit(struct rbd_obj_request *obj_request)
-{
-	struct rbd_device *rbd_dev = obj_request->img_request->rbd_dev;
-	struct rbd_obj_request *stat_request;
-	struct page **pages;
-	int ret;
-
-	stat_request = rbd_obj_request_create(OBJ_REQUEST_NODATA);
-	if (!stat_request)
-		return -ENOMEM;
-
-	stat_request->object_no = obj_request->object_no;
-
-	stat_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1,
-						   stat_request);
-	if (!stat_request->osd_req) {
-		ret = -ENOMEM;
-		goto fail_stat_request;
-	}
-
-	/*
-	 * The response data for a STAT call consists of:
-	 *     le64 length;
-	 *     struct {
-	 *         le32 tv_sec;
-	 *         le32 tv_nsec;
-	 *     } mtime;
-	 */
-	pages = ceph_alloc_page_vector(1, GFP_NOIO);
-	if (IS_ERR(pages)) {
-		ret = PTR_ERR(pages);
-		goto fail_stat_request;
-	}
-
-	osd_req_op_init(stat_request->osd_req, 0, CEPH_OSD_OP_STAT, 0);
-	osd_req_op_raw_data_in_pages(stat_request->osd_req, 0, pages,
-				     8 + sizeof(struct ceph_timespec),
-				     0, false, true);
-
-	rbd_obj_request_get(obj_request);
-	stat_request->obj_request = obj_request;
-	stat_request->callback = rbd_img_obj_exists_callback;
-
-	rbd_obj_request_submit(stat_request);
-	return 0;
-
-fail_stat_request:
-	rbd_obj_request_put(stat_request);
-	return ret;
-}
-
-static bool img_obj_request_simple(struct rbd_obj_request *obj_request)
-{
-	struct rbd_img_request *img_request = obj_request->img_request;
-	struct rbd_device *rbd_dev = img_request->rbd_dev;
-
-	/* Reads */
-	if (!img_request_write_test(img_request) &&
-	    !img_request_discard_test(img_request))
-		return true;
-
-	/* Non-layered writes */
-	if (!img_request_layered_test(img_request))
-		return true;
-
-	/*
-	 * Layered writes outside of the parent overlap range don't
-	 * share any data with the parent.
-	 */
-	if (!obj_request_overlaps_parent(obj_request))
-		return true;
-
-	/*
-	 * Entire-object layered writes - we will overwrite whatever
-	 * parent data there is anyway.
-	 */
-	if (!obj_request->offset &&
-	    obj_request->length == rbd_obj_bytes(&rbd_dev->header))
-		return true;
-
-	/*
-	 * If the object is known to already exist, its parent data has
-	 * already been copied.
-	 */
-	if (obj_request_known_test(obj_request) &&
-	    obj_request_exists_test(obj_request))
-		return true;
-
-	return false;
-}
-
-static int rbd_img_obj_request_submit(struct rbd_obj_request *obj_request)
-{
-	rbd_assert(obj_request_img_data_test(obj_request));
-	rbd_assert(obj_request_type_valid(obj_request->type));
-	rbd_assert(obj_request->img_request);
-
-	if (img_obj_request_simple(obj_request)) {
-		rbd_obj_request_submit(obj_request);
-		return 0;
-	}
-
-	/*
-	 * 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 (obj_request_known_test(obj_request))
-		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_obj_request *obj_request;
@@ -3131,106 +2505,6 @@ static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
 	return 0;
 }
 
-static void rbd_img_parent_read_callback(struct rbd_img_request *img_request)
-{
-	struct rbd_obj_request *obj_request;
-	struct rbd_device *rbd_dev;
-	u64 obj_end;
-	u64 img_xferred;
-	int img_result;
-
-	rbd_assert(img_request_child_test(img_request));
-
-	/* First get what we need from the image request and release it */
-
-	obj_request = img_request->obj_request;
-	img_xferred = img_request->xferred;
-	img_result = img_request->result;
-	rbd_img_request_put(img_request);
-
-	/*
-	 * If the overlap has become 0 (most likely because the
-	 * image has been flattened) we need to re-submit the
-	 * original request.
-	 */
-	rbd_assert(obj_request);
-	rbd_assert(obj_request->img_request);
-	rbd_dev = obj_request->img_request->rbd_dev;
-	if (!rbd_dev->parent_overlap) {
-		rbd_obj_request_submit(obj_request);
-		return;
-	}
-
-	obj_request->result = img_result;
-	if (obj_request->result)
-		goto out;
-
-	/*
-	 * We need to zero anything beyond the parent overlap
-	 * boundary.  Since rbd_img_obj_request_read_callback()
-	 * will zero anything beyond the end of a short read, an
-	 * easy way to do this is to pretend the data from the
-	 * parent came up short--ending at the overlap boundary.
-	 */
-	rbd_assert(obj_request->img_offset < U64_MAX - obj_request->length);
-	obj_end = obj_request->img_offset + obj_request->length;
-	if (obj_end > rbd_dev->parent_overlap) {
-		u64 xferred = 0;
-
-		if (obj_request->img_offset < rbd_dev->parent_overlap)
-			xferred = rbd_dev->parent_overlap -
-					obj_request->img_offset;
-
-		obj_request->xferred = min(img_xferred, xferred);
-	} else {
-		obj_request->xferred = img_xferred;
-	}
-out:
-	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_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_valid(obj_request->type));
-
-	/* rbd_read_finish(obj_request, obj_request->length); */
-	img_request = rbd_parent_request_create(obj_request,
-						obj_request->img_offset,
-						obj_request->length);
-	result = -ENOMEM;
-	if (!img_request)
-		goto out_err;
-
-	if (obj_request->type == OBJ_REQUEST_BIO)
-		result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO,
-						&obj_request->bio_pos);
-	else
-		result = rbd_img_request_fill(img_request, OBJ_REQUEST_BVECS,
-						&obj_request->bvec_pos);
-	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_handle_write_guard(struct rbd_obj_request *obj_req)
 {
 	struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;