Merge tag 'ceph-for-5.1-rc1' of git://github.com/ceph/ceph-client

Pull ceph updates from Ilya Dryomov:
 "The highlights are:

   - rbd will now ignore discards that aren't aligned and big enough to
     actually free up some space (myself). This is controlled by the new
     alloc_size map option and can be disabled if needed.

   - support for rbd deep-flatten feature (myself). Deep-flatten allows
     "rbd flatten" to fully disconnect the clone image and its snapshots
     from the parent and make the parent snapshot removable.

   - a new round of cap handling improvements (Zheng Yan). The kernel
     client should now be much more prompt about releasing its caps and
     it is possible to put a limit on the number of caps held.

   - support for getting ceph.dir.pin extended attribute (Zheng Yan)"

* tag 'ceph-for-5.1-rc1' of git://github.com/ceph/ceph-client: (26 commits)
  Documentation: modern versions of ceph are not backed by btrfs
  rbd: advertise support for RBD_FEATURE_DEEP_FLATTEN
  rbd: whole-object write and zeroout should copyup when snapshots exist
  rbd: copyup with an empty snapshot context (aka deep-copyup)
  rbd: introduce rbd_obj_issue_copyup_ops()
  rbd: stop copying num_osd_ops in rbd_obj_issue_copyup()
  rbd: factor out __rbd_osd_req_create()
  rbd: clear ->xferred on error from rbd_obj_issue_copyup()
  rbd: remove experimental designation from kernel layering
  ceph: add mount option to limit caps count
  ceph: periodically trim stale dentries
  ceph: delete stale dentry when last reference is dropped
  ceph: remove dentry_lru file from debugfs
  ceph: touch existing cap when handling reply
  ceph: pass inclusive lend parameter to filemap_write_and_wait_range()
  rbd: round off and ignore discards that are too small
  rbd: handle DISCARD and WRITE_ZEROES separately
  rbd: get rid of obj_req->obj_request_count
  libceph: use struct_size() for kmalloc() in crush_decode()
  ceph: send cap releases more aggressively
  ...

1 files changed, 297 insertions, 103 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 74088d8dbaf3..4ba967d65cf9 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -115,12 +115,14 @@ static int atomic_dec_return_safe(atomic_t *v)
 #define RBD_FEATURE_LAYERING		(1ULL<<0)
 #define RBD_FEATURE_STRIPINGV2		(1ULL<<1)
 #define RBD_FEATURE_EXCLUSIVE_LOCK	(1ULL<<2)
+#define RBD_FEATURE_DEEP_FLATTEN	(1ULL<<5)
 #define RBD_FEATURE_DATA_POOL		(1ULL<<7)
 #define RBD_FEATURE_OPERATIONS		(1ULL<<8)
 
 #define RBD_FEATURES_ALL	(RBD_FEATURE_LAYERING |		\
 				 RBD_FEATURE_STRIPINGV2 |	\
 				 RBD_FEATURE_EXCLUSIVE_LOCK |	\
+				 RBD_FEATURE_DEEP_FLATTEN |	\
 				 RBD_FEATURE_DATA_POOL |	\
 				 RBD_FEATURE_OPERATIONS)
 
@@ -214,28 +216,40 @@ enum obj_operation_type {
 	OBJ_OP_READ = 1,
 	OBJ_OP_WRITE,
 	OBJ_OP_DISCARD,
+	OBJ_OP_ZEROOUT,
 };
 
 /*
  * Writes go through the following state machine to deal with
  * layering:
  *
- *                       need copyup
- * RBD_OBJ_WRITE_GUARD ---------------> RBD_OBJ_WRITE_COPYUP
- *        |     ^                              |
- *        v     \------------------------------/
- *      done
- *        ^
- *        |
- * RBD_OBJ_WRITE_FLAT
+ *            . . . . . RBD_OBJ_WRITE_GUARD. . . . . . . . . . . . . .
+ *            .                 |                                    .
+ *            .                 v                                    .
+ *            .    RBD_OBJ_WRITE_READ_FROM_PARENT. . .               .
+ *            .                 |                    .               .
+ *            .                 v                    v (deep-copyup  .
+ *    (image  .   RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC   .  not needed)  .
+ * flattened) v                 |                    .               .
+ *            .                 v                    .               .
+ *            . . . .RBD_OBJ_WRITE_COPYUP_OPS. . . . .      (copyup  .
+ *                              |                        not needed) v
+ *                              v                                    .
+ *                            done . . . . . . . . . . . . . . . . . .
+ *                              ^
+ *                              |
+ *                     RBD_OBJ_WRITE_FLAT
  *
  * Writes start in RBD_OBJ_WRITE_GUARD or _FLAT, depending on whether
- * there is a parent or not.
+ * assert_exists guard is needed or not (in some cases it's not needed
+ * even if there is a parent).
  */
 enum rbd_obj_write_state {
 	RBD_OBJ_WRITE_FLAT = 1,
 	RBD_OBJ_WRITE_GUARD,
-	RBD_OBJ_WRITE_COPYUP,
+	RBD_OBJ_WRITE_READ_FROM_PARENT,
+	RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC,
+	RBD_OBJ_WRITE_COPYUP_OPS,
 };
 
 struct rbd_obj_request {
@@ -291,7 +305,6 @@ struct rbd_img_request {
 	int			result;	/* first nonzero obj_request result */
 
 	struct list_head	object_extents;	/* obj_req.ex structs */
-	u32			obj_request_count;
 	u32			pending_count;
 
 	struct kref		kref;
@@ -421,6 +434,10 @@ static DEFINE_IDA(rbd_dev_id_ida);
 
 static struct workqueue_struct *rbd_wq;
 
+static struct ceph_snap_context rbd_empty_snapc = {
+	.nref = REFCOUNT_INIT(1),
+};
+
 /*
  * single-major requires >= 0.75 version of userspace rbd utility.
  */
@@ -732,6 +749,7 @@ static struct rbd_client *rbd_client_find(struct ceph_options *ceph_opts)
  */
 enum {
 	Opt_queue_depth,
+	Opt_alloc_size,
 	Opt_lock_timeout,
 	Opt_last_int,
 	/* int args above */
@@ -748,6 +766,7 @@ enum {
 
 static match_table_t rbd_opts_tokens = {
 	{Opt_queue_depth, "queue_depth=%d"},
+	{Opt_alloc_size, "alloc_size=%d"},
 	{Opt_lock_timeout, "lock_timeout=%d"},
 	/* int args above */
 	{Opt_pool_ns, "_pool_ns=%s"},
@@ -764,6 +783,7 @@ static match_table_t rbd_opts_tokens = {
 
 struct rbd_options {
 	int	queue_depth;
+	int	alloc_size;
 	unsigned long	lock_timeout;
 	bool	read_only;
 	bool	lock_on_read;
@@ -772,6 +792,7 @@ struct rbd_options {
 };
 
 #define RBD_QUEUE_DEPTH_DEFAULT	BLKDEV_MAX_RQ
+#define RBD_ALLOC_SIZE_DEFAULT	(64 * 1024)
 #define RBD_LOCK_TIMEOUT_DEFAULT 0  /* no timeout */
 #define RBD_READ_ONLY_DEFAULT	false
 #define RBD_LOCK_ON_READ_DEFAULT false
@@ -811,6 +832,17 @@ static int parse_rbd_opts_token(char *c, void *private)
 		}
 		pctx->opts->queue_depth = intval;
 		break;
+	case Opt_alloc_size:
+		if (intval < 1) {
+			pr_err("alloc_size out of range\n");
+			return -EINVAL;
+		}
+		if (!is_power_of_2(intval)) {
+			pr_err("alloc_size must be a power of 2\n");
+			return -EINVAL;
+		}
+		pctx->opts->alloc_size = intval;
+		break;
 	case Opt_lock_timeout:
 		/* 0 is "wait forever" (i.e. infinite timeout) */
 		if (intval < 0 || intval > INT_MAX / 1000) {
@@ -857,6 +889,8 @@ static char* obj_op_name(enum obj_operation_type op_type)
 		return "write";
 	case OBJ_OP_DISCARD:
 		return "discard";
+	case OBJ_OP_ZEROOUT:
+		return "zeroout";
 	default:
 		return "???";
 	}
@@ -1344,7 +1378,6 @@ static inline void rbd_img_obj_request_add(struct rbd_img_request *img_request,
 
 	/* Image request now owns object's original reference */
 	obj_request->img_request = img_request;
-	img_request->obj_request_count++;
 	img_request->pending_count++;
 	dout("%s: img %p obj %p\n", __func__, img_request, obj_request);
 }
@@ -1354,8 +1387,6 @@ static inline void rbd_img_obj_request_del(struct rbd_img_request *img_request,
 {
 	dout("%s: img %p obj %p\n", __func__, img_request, obj_request);
 	list_del(&obj_request->ex.oe_item);
-	rbd_assert(img_request->obj_request_count > 0);
-	img_request->obj_request_count--;
 	rbd_assert(obj_request->img_request == img_request);
 	rbd_obj_request_put(obj_request);
 }
@@ -1409,6 +1440,19 @@ static bool rbd_obj_is_tail(struct rbd_obj_request *obj_req)
 					rbd_dev->layout.object_size;
 }
 
+/*
+ * Must be called after rbd_obj_calc_img_extents().
+ */
+static bool rbd_obj_copyup_enabled(struct rbd_obj_request *obj_req)
+{
+	if (!obj_req->num_img_extents ||
+	    (rbd_obj_is_entire(obj_req) &&
+	     !obj_req->img_request->snapc->num_snaps))
+		return false;
+
+	return true;
+}
+
 static u64 rbd_obj_img_extents_bytes(struct rbd_obj_request *obj_req)
 {
 	return ceph_file_extents_bytes(obj_req->img_extents,
@@ -1422,6 +1466,7 @@ static bool rbd_img_is_write(struct rbd_img_request *img_req)
 		return false;
 	case OBJ_OP_WRITE:
 	case OBJ_OP_DISCARD:
+	case OBJ_OP_ZEROOUT:
 		return true;
 	default:
 		BUG();
@@ -1470,18 +1515,16 @@ static void rbd_osd_req_format_write(struct rbd_obj_request *obj_request)
 }
 
 static struct ceph_osd_request *
-rbd_osd_req_create(struct rbd_obj_request *obj_req, unsigned int num_ops)
+__rbd_osd_req_create(struct rbd_obj_request *obj_req,
+		     struct ceph_snap_context *snapc, unsigned int num_ops)
 {
-	struct rbd_img_request *img_req = obj_req->img_request;
-	struct rbd_device *rbd_dev = img_req->rbd_dev;
+	struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
 	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
 	struct ceph_osd_request *req;
 	const char *name_format = rbd_dev->image_format == 1 ?
 				      RBD_V1_DATA_FORMAT : RBD_V2_DATA_FORMAT;
 
-	req = ceph_osdc_alloc_request(osdc,
-			(rbd_img_is_write(img_req) ? img_req->snapc : NULL),
-			num_ops, false, GFP_NOIO);
+	req = ceph_osdc_alloc_request(osdc, snapc, num_ops, false, GFP_NOIO);
 	if (!req)
 		return NULL;
 
@@ -1506,6 +1549,13 @@ err_req:
 	return NULL;
 }
 
+static struct ceph_osd_request *
+rbd_osd_req_create(struct rbd_obj_request *obj_req, unsigned int num_ops)
+{
+	return __rbd_osd_req_create(obj_req, obj_req->img_request->snapc,
+				    num_ops);
+}
+
 static void rbd_osd_req_destroy(struct ceph_osd_request *osd_req)
 {
 	ceph_osdc_put_request(osd_req);
@@ -1671,7 +1721,6 @@ static void rbd_img_request_destroy(struct kref *kref)
 
 	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_layered_test(img_request)) {
 		img_request_layered_clear(img_request);
@@ -1754,7 +1803,7 @@ static void rbd_osd_req_setup_data(struct rbd_obj_request *obj_req, u32 which)
 
 static int rbd_obj_setup_read(struct rbd_obj_request *obj_req)
 {
-	obj_req->osd_req = rbd_osd_req_create(obj_req, 1);
+	obj_req->osd_req = __rbd_osd_req_create(obj_req, NULL, 1);
 	if (!obj_req->osd_req)
 		return -ENOMEM;
 
@@ -1790,6 +1839,11 @@ static int __rbd_obj_setup_stat(struct rbd_obj_request *obj_req,
 	return 0;
 }
 
+static int count_write_ops(struct rbd_obj_request *obj_req)
+{
+	return 2; /* setallochint + write/writefull */
+}
+
 static void __rbd_obj_setup_write(struct rbd_obj_request *obj_req,
 				  unsigned int which)
 {
@@ -1816,6 +1870,7 @@ static void __rbd_obj_setup_write(struct rbd_obj_request *obj_req,
 static int rbd_obj_setup_write(struct rbd_obj_request *obj_req)
 {
 	unsigned int num_osd_ops, which = 0;
+	bool need_guard;
 	int ret;
 
 	/* reverse map the entire object onto the parent */
@@ -1823,47 +1878,112 @@ static int rbd_obj_setup_write(struct rbd_obj_request *obj_req)
 	if (ret)
 		return ret;
 
-	if (obj_req->num_img_extents) {
-		obj_req->write_state = RBD_OBJ_WRITE_GUARD;
-		num_osd_ops = 3; /* stat + setallochint + write/writefull */
-	} else {
-		obj_req->write_state = RBD_OBJ_WRITE_FLAT;
-		num_osd_ops = 2; /* setallochint + write/writefull */
-	}
+	need_guard = rbd_obj_copyup_enabled(obj_req);
+	num_osd_ops = need_guard + count_write_ops(obj_req);
 
 	obj_req->osd_req = rbd_osd_req_create(obj_req, num_osd_ops);
 	if (!obj_req->osd_req)
 		return -ENOMEM;
 
-	if (obj_req->num_img_extents) {
+	if (need_guard) {
 		ret = __rbd_obj_setup_stat(obj_req, which++);
 		if (ret)
 			return ret;
+
+		obj_req->write_state = RBD_OBJ_WRITE_GUARD;
+	} else {
+		obj_req->write_state = RBD_OBJ_WRITE_FLAT;
 	}
 
 	__rbd_obj_setup_write(obj_req, which);
 	return 0;
 }
 
-static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req,
+static u16 truncate_or_zero_opcode(struct rbd_obj_request *obj_req)
+{
+	return rbd_obj_is_tail(obj_req) ? CEPH_OSD_OP_TRUNCATE :
+					  CEPH_OSD_OP_ZERO;
+}
+
+static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
+{
+	struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
+	u64 off = obj_req->ex.oe_off;
+	u64 next_off = obj_req->ex.oe_off + obj_req->ex.oe_len;
+	int ret;
+
+	/*
+	 * Align the range to alloc_size boundary and punt on discards
+	 * that are too small to free up any space.
+	 *
+	 * alloc_size == object_size && is_tail() is a special case for
+	 * filestore with filestore_punch_hole = false, needed to allow
+	 * truncate (in addition to delete).
+	 */
+	if (rbd_dev->opts->alloc_size != rbd_dev->layout.object_size ||
+	    !rbd_obj_is_tail(obj_req)) {
+		off = round_up(off, rbd_dev->opts->alloc_size);
+		next_off = round_down(next_off, rbd_dev->opts->alloc_size);
+		if (off >= next_off)
+			return 1;
+	}
+
+	/* reverse map the entire object onto the parent */
+	ret = rbd_obj_calc_img_extents(obj_req, true);
+	if (ret)
+		return ret;
+
+	obj_req->osd_req = rbd_osd_req_create(obj_req, 1);
+	if (!obj_req->osd_req)
+		return -ENOMEM;
+
+	if (rbd_obj_is_entire(obj_req) && !obj_req->num_img_extents) {
+		osd_req_op_init(obj_req->osd_req, 0, CEPH_OSD_OP_DELETE, 0);
+	} else {
+		dout("%s %p %llu~%llu -> %llu~%llu\n", __func__,
+		     obj_req, obj_req->ex.oe_off, obj_req->ex.oe_len,
+		     off, next_off - off);
+		osd_req_op_extent_init(obj_req->osd_req, 0,
+				       truncate_or_zero_opcode(obj_req),
+				       off, next_off - off, 0, 0);
+	}
+
+	obj_req->write_state = RBD_OBJ_WRITE_FLAT;
+	rbd_osd_req_format_write(obj_req);
+	return 0;
+}
+
+static int count_zeroout_ops(struct rbd_obj_request *obj_req)
+{
+	int num_osd_ops;
+
+	if (rbd_obj_is_entire(obj_req) && obj_req->num_img_extents &&
+	    !rbd_obj_copyup_enabled(obj_req))
+		num_osd_ops = 2; /* create + truncate */
+	else
+		num_osd_ops = 1; /* delete/truncate/zero */
+
+	return num_osd_ops;
+}
+
+static void __rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req,
 				    unsigned int which)
 {
 	u16 opcode;
 
 	if (rbd_obj_is_entire(obj_req)) {
 		if (obj_req->num_img_extents) {
-			osd_req_op_init(obj_req->osd_req, which++,
-					CEPH_OSD_OP_CREATE, 0);
+			if (!rbd_obj_copyup_enabled(obj_req))
+				osd_req_op_init(obj_req->osd_req, which++,
+						CEPH_OSD_OP_CREATE, 0);
 			opcode = CEPH_OSD_OP_TRUNCATE;
 		} else {
 			osd_req_op_init(obj_req->osd_req, which++,
 					CEPH_OSD_OP_DELETE, 0);
 			opcode = 0;
 		}
-	} else if (rbd_obj_is_tail(obj_req)) {
-		opcode = CEPH_OSD_OP_TRUNCATE;
 	} else {
-		opcode = CEPH_OSD_OP_ZERO;
+		opcode = truncate_or_zero_opcode(obj_req);
 	}
 
 	if (opcode)
@@ -1875,9 +1995,10 @@ static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req,
 	rbd_osd_req_format_write(obj_req);
 }
 
-static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
+static int rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req)
 {
 	unsigned int num_osd_ops, which = 0;
+	bool need_guard;
 	int ret;
 
 	/* reverse map the entire object onto the parent */
@@ -1885,33 +2006,24 @@ static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
 	if (ret)
 		return ret;
 
-	if (rbd_obj_is_entire(obj_req)) {
-		obj_req->write_state = RBD_OBJ_WRITE_FLAT;
-		if (obj_req->num_img_extents)
-			num_osd_ops = 2; /* create + truncate */
-		else
-			num_osd_ops = 1; /* delete */
-	} else {
-		if (obj_req->num_img_extents) {
-			obj_req->write_state = RBD_OBJ_WRITE_GUARD;
-			num_osd_ops = 2; /* stat + truncate/zero */
-		} else {
-			obj_req->write_state = RBD_OBJ_WRITE_FLAT;
-			num_osd_ops = 1; /* truncate/zero */
-		}
-	}
+	need_guard = rbd_obj_copyup_enabled(obj_req);
+	num_osd_ops = need_guard + count_zeroout_ops(obj_req);
 
 	obj_req->osd_req = rbd_osd_req_create(obj_req, num_osd_ops);
 	if (!obj_req->osd_req)
 		return -ENOMEM;
 
-	if (!rbd_obj_is_entire(obj_req) && obj_req->num_img_extents) {
+	if (need_guard) {
 		ret = __rbd_obj_setup_stat(obj_req, which++);
 		if (ret)
 			return ret;
+
+		obj_req->write_state = RBD_OBJ_WRITE_GUARD;
+	} else {
+		obj_req->write_state = RBD_OBJ_WRITE_FLAT;
 	}
 
-	__rbd_obj_setup_discard(obj_req, which);
+	__rbd_obj_setup_zeroout(obj_req, which);
 	return 0;
 }
 
@@ -1922,10 +2034,10 @@ static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
  */
 static int __rbd_img_fill_request(struct rbd_img_request *img_req)
 {
-	struct rbd_obj_request *obj_req;
+	struct rbd_obj_request *obj_req, *next_obj_req;
 	int ret;
 
-	for_each_obj_request(img_req, obj_req) {
+	for_each_obj_request_safe(img_req, obj_req, next_obj_req) {
 		switch (img_req->op_type) {
 		case OBJ_OP_READ:
 			ret = rbd_obj_setup_read(obj_req);
@@ -1936,11 +2048,20 @@ static int __rbd_img_fill_request(struct rbd_img_request *img_req)
 		case OBJ_OP_DISCARD:
 			ret = rbd_obj_setup_discard(obj_req);
 			break;
+		case OBJ_OP_ZEROOUT:
+			ret = rbd_obj_setup_zeroout(obj_req);
+			break;
 		default:
 			rbd_assert(0);
 		}
-		if (ret)
+		if (ret < 0)
 			return ret;
+		if (ret > 0) {
+			img_req->xferred += obj_req->ex.oe_len;
+			img_req->pending_count--;
+			rbd_img_obj_request_del(img_req, obj_req);
+			continue;
+		}
 
 		ret = ceph_osdc_alloc_messages(obj_req->osd_req, GFP_NOIO);
 		if (ret)
@@ -2356,21 +2477,19 @@ static bool is_zero_bvecs(struct bio_vec *bvecs, u32 bytes)
 	return true;
 }
 
-static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes)
+#define MODS_ONLY	U32_MAX
+
+static int rbd_obj_issue_copyup_empty_snapc(struct rbd_obj_request *obj_req,
+					    u32 bytes)
 {
-	unsigned int num_osd_ops = obj_req->osd_req->r_num_ops;
 	int ret;
 
 	dout("%s obj_req %p bytes %u\n", __func__, obj_req, bytes);
 	rbd_assert(obj_req->osd_req->r_ops[0].op == CEPH_OSD_OP_STAT);
+	rbd_assert(bytes > 0 && bytes != MODS_ONLY);
 	rbd_osd_req_destroy(obj_req->osd_req);
 
-	/*
-	 * Create a copyup request with the same number of OSD ops as
-	 * the original request.  The original request was stat + op(s),
-	 * the new copyup request will be copyup + the same op(s).
-	 */
-	obj_req->osd_req = rbd_osd_req_create(obj_req, num_osd_ops);
+	obj_req->osd_req = __rbd_osd_req_create(obj_req, &rbd_empty_snapc, 1);
 	if (!obj_req->osd_req)
 		return -ENOMEM;
 
@@ -2378,27 +2497,65 @@ static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes)
 	if (ret)
 		return ret;
 
-	/*
-	 * Only send non-zero copyup data to save some I/O and network
-	 * bandwidth -- zero copyup data is equivalent to the object not
-	 * existing.
-	 */
-	if (is_zero_bvecs(obj_req->copyup_bvecs, bytes)) {
-		dout("%s obj_req %p detected zeroes\n", __func__, obj_req);
-		bytes = 0;
-	}
 	osd_req_op_cls_request_data_bvecs(obj_req->osd_req, 0,
 					  obj_req->copyup_bvecs,
 					  obj_req->copyup_bvec_count,
 					  bytes);
+	rbd_osd_req_format_write(obj_req);
 
-	switch (obj_req->img_request->op_type) {
+	ret = ceph_osdc_alloc_messages(obj_req->osd_req, GFP_NOIO);
+	if (ret)
+		return ret;
+
+	rbd_obj_request_submit(obj_req);
+	return 0;
+}
+
+static int rbd_obj_issue_copyup_ops(struct rbd_obj_request *obj_req, u32 bytes)
+{
+	struct rbd_img_request *img_req = obj_req->img_request;
+	unsigned int num_osd_ops = (bytes != MODS_ONLY);
+	unsigned int which = 0;
+	int ret;
+
+	dout("%s obj_req %p bytes %u\n", __func__, obj_req, bytes);
+	rbd_assert(obj_req->osd_req->r_ops[0].op == CEPH_OSD_OP_STAT ||
+		   obj_req->osd_req->r_ops[0].op == CEPH_OSD_OP_CALL);
+	rbd_osd_req_destroy(obj_req->osd_req);
+
+	switch (img_req->op_type) {
 	case OBJ_OP_WRITE:
-		__rbd_obj_setup_write(obj_req, 1);
+		num_osd_ops += count_write_ops(obj_req);
 		break;
-	case OBJ_OP_DISCARD:
-		rbd_assert(!rbd_obj_is_entire(obj_req));
-		__rbd_obj_setup_discard(obj_req, 1);
+	case OBJ_OP_ZEROOUT:
+		num_osd_ops += count_zeroout_ops(obj_req);
+		break;
+	default:
+		rbd_assert(0);
+	}
+
+	obj_req->osd_req = rbd_osd_req_create(obj_req, num_osd_ops);
+	if (!obj_req->osd_req)
+		return -ENOMEM;
+
+	if (bytes != MODS_ONLY) {
+		ret = osd_req_op_cls_init(obj_req->osd_req, which, "rbd",
+					  "copyup");
+		if (ret)
+			return ret;
+
+		osd_req_op_cls_request_data_bvecs(obj_req->osd_req, which++,
+						  obj_req->copyup_bvecs,
+						  obj_req->copyup_bvec_count,
+						  bytes);
+	}
+
+	switch (img_req->op_type) {
+	case OBJ_OP_WRITE:
+		__rbd_obj_setup_write(obj_req, which);
+		break;
+	case OBJ_OP_ZEROOUT:
+		__rbd_obj_setup_zeroout(obj_req, which);
 		break;
 	default:
 		rbd_assert(0);
@@ -2412,6 +2569,33 @@ static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes)
 	return 0;
 }
 
+static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes)
+{
+	/*
+	 * Only send non-zero copyup data to save some I/O and network
+	 * bandwidth -- zero copyup data is equivalent to the object not
+	 * existing.
+	 */
+	if (is_zero_bvecs(obj_req->copyup_bvecs, bytes)) {
+		dout("%s obj_req %p detected zeroes\n", __func__, obj_req);
+		bytes = 0;
+	}
+
+	if (obj_req->img_request->snapc->num_snaps && bytes > 0) {
+		/*
+		 * Send a copyup request with an empty snapshot context to
+		 * deep-copyup the object through all existing snapshots.
+		 * A second request with the current snapshot context will be
+		 * sent for the actual modification.
+		 */
+		obj_req->write_state = RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC;
+		return rbd_obj_issue_copyup_empty_snapc(obj_req, bytes);
+	}
+
+	obj_req->write_state = RBD_OBJ_WRITE_COPYUP_OPS;
+	return rbd_obj_issue_copyup_ops(obj_req, bytes);
+}
+
 static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
 {
 	u32 i;
@@ -2451,22 +2635,19 @@ static int rbd_obj_handle_write_guard(struct rbd_obj_request *obj_req)
 	if (!obj_req->num_img_extents) {
 		/*
 		 * The overlap has become 0 (most likely because the
-		 * image has been flattened).  Use rbd_obj_issue_copyup()
-		 * to re-submit the original write request -- the copyup
-		 * operation itself will be a no-op, since someone must
-		 * have populated the child object while we weren't
-		 * looking.  Move to WRITE_FLAT state as we'll be done
-		 * with the operation once the null copyup completes.
+		 * image has been flattened).  Re-submit the original write
+		 * request -- pass MODS_ONLY since the copyup isn't needed
+		 * anymore.
 		 */
-		obj_req->write_state = RBD_OBJ_WRITE_FLAT;
-		return rbd_obj_issue_copyup(obj_req, 0);
+		obj_req->write_state = RBD_OBJ_WRITE_COPYUP_OPS;
+		return rbd_obj_issue_copyup_ops(obj_req, MODS_ONLY);
 	}
 
 	ret = setup_copyup_bvecs(obj_req, rbd_obj_img_extents_bytes(obj_req));
 	if (ret)
 		return ret;
 
-	obj_req->write_state = RBD_OBJ_WRITE_COPYUP;
+	obj_req->write_state = RBD_OBJ_WRITE_READ_FROM_PARENT;
 	return rbd_obj_read_from_parent(obj_req);
 }
 
@@ -2474,7 +2655,6 @@ static bool rbd_obj_handle_write(struct rbd_obj_request *obj_req)
 {
 	int ret;
 
-again:
 	switch (obj_req->write_state) {
 	case RBD_OBJ_WRITE_GUARD:
 		rbd_assert(!obj_req->xferred);
@@ -2493,6 +2673,7 @@ again:
 		}
 		/* fall through */
 	case RBD_OBJ_WRITE_FLAT:
+	case RBD_OBJ_WRITE_COPYUP_OPS:
 		if (!obj_req->result)
 			/*
 			 * There is no such thing as a successful short
@@ -2500,15 +2681,26 @@ again:
 			 */
 			obj_req->xferred = obj_req->ex.oe_len;
 		return true;
-	case RBD_OBJ_WRITE_COPYUP:
-		obj_req->write_state = RBD_OBJ_WRITE_GUARD;
+	case RBD_OBJ_WRITE_READ_FROM_PARENT:
 		if (obj_req->result)
-			goto again;
+			return true;
 
 		rbd_assert(obj_req->xferred);
 		ret = rbd_obj_issue_copyup(obj_req, obj_req->xferred);
 		if (ret) {
 			obj_req->result = ret;
+			obj_req->xferred = 0;
+			return true;
+		}
+		return false;
+	case RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC:
+		if (obj_req->result)
+			return true;
+
+		obj_req->write_state = RBD_OBJ_WRITE_COPYUP_OPS;
+		ret = rbd_obj_issue_copyup_ops(obj_req, MODS_ONLY);
+		if (ret) {
+			obj_req->result = ret;
 			return true;
 		}
 		return false;
@@ -2528,6 +2720,7 @@ static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req)
 	case OBJ_OP_WRITE:
 		return rbd_obj_handle_write(obj_req);
 	case OBJ_OP_DISCARD:
+	case OBJ_OP_ZEROOUT:
 		if (rbd_obj_handle_write(obj_req)) {
 			/*
 			 * Hide -ENOENT from delete/truncate/zero -- discarding
@@ -3640,9 +3833,11 @@ static void rbd_queue_workfn(struct work_struct *work)
 
 	switch (req_op(rq)) {
 	case REQ_OP_DISCARD:
-	case REQ_OP_WRITE_ZEROES:
 		op_type = OBJ_OP_DISCARD;
 		break;
+	case REQ_OP_WRITE_ZEROES:
+		op_type = OBJ_OP_ZEROOUT;
+		break;
 	case REQ_OP_WRITE:
 		op_type = OBJ_OP_WRITE;
 		break;
@@ -3722,12 +3917,12 @@ static void rbd_queue_workfn(struct work_struct *work)
 	img_request->rq = rq;
 	snapc = NULL; /* img_request consumes a ref */
 
-	if (op_type == OBJ_OP_DISCARD)
+	if (op_type == OBJ_OP_DISCARD || op_type == OBJ_OP_ZEROOUT)
 		result = rbd_img_fill_nodata(img_request, offset, length);
 	else
 		result = rbd_img_fill_from_bio(img_request, offset, length,
 					       rq->bio);
-	if (result)
+	if (result || !img_request->pending_count)
 		goto err_img_request;
 
 	rbd_img_request_submit(img_request);
@@ -5388,6 +5583,7 @@ static int rbd_add_parse_args(const char *buf,
 
 	pctx.opts->read_only = RBD_READ_ONLY_DEFAULT;
 	pctx.opts->queue_depth = RBD_QUEUE_DEPTH_DEFAULT;
+	pctx.opts->alloc_size = RBD_ALLOC_SIZE_DEFAULT;
 	pctx.opts->lock_timeout = RBD_LOCK_TIMEOUT_DEFAULT;
 	pctx.opts->lock_on_read = RBD_LOCK_ON_READ_DEFAULT;
 	pctx.opts->exclusive = RBD_EXCLUSIVE_DEFAULT;
@@ -5795,14 +5991,6 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
 		ret = rbd_dev_v2_parent_info(rbd_dev);
 		if (ret)
 			goto err_out_probe;
-
-		/*
-		 * Need to warn users if this image is the one being
-		 * mapped and has a parent.
-		 */
-		if (!depth && rbd_dev->parent_spec)
-			rbd_warn(rbd_dev,
-				 "WARNING: kernel layering is EXPERIMENTAL!");
 	}
 
 	ret = rbd_dev_probe_parent(rbd_dev, depth);
@@ -5885,6 +6073,12 @@ static ssize_t do_rbd_add(struct bus_type *bus,
 	if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
 		rbd_dev->opts->read_only = true;
 
+	if (rbd_dev->opts->alloc_size > rbd_dev->layout.object_size) {
+		rbd_warn(rbd_dev, "alloc_size adjusted to %u",
+			 rbd_dev->layout.object_size);
+		rbd_dev->opts->alloc_size = rbd_dev->layout.object_size;
+	}
+
 	rc = rbd_dev_device_setup(rbd_dev);
 	if (rc)
 		goto err_out_image_probe;