1 files changed, 491 insertions, 47 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index e1e38b11f48..9712fad82bc 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -31,6 +31,7 @@
 #include <linux/ceph/osd_client.h>
 #include <linux/ceph/mon_client.h>
 #include <linux/ceph/decode.h>
+#include <linux/parser.h>
 
 #include <linux/kernel.h>
 #include <linux/device.h>
@@ -54,6 +55,8 @@
 
 #define DEV_NAME_LEN		32
 
+#define RBD_NOTIFY_TIMEOUT_DEFAULT 10
+
 /*
  * block device image metadata (in-memory version)
  */
@@ -71,6 +74,12 @@ struct rbd_image_header {
 
 	char *snap_names;
 	u64 *snap_sizes;
+
+	u64 obj_version;
+};
+
+struct rbd_options {
+	int	notify_timeout;
 };
 
 /*
@@ -78,10 +87,13 @@ struct rbd_image_header {
  */
 struct rbd_client {
 	struct ceph_client	*client;
+	struct rbd_options	*rbd_opts;
 	struct kref		kref;
 	struct list_head	node;
 };
 
+struct rbd_req_coll;
+
 /*
  * a single io request
  */
@@ -90,6 +102,24 @@ struct rbd_request {
 	struct bio		*bio;		/* cloned bio */
 	struct page		**pages;	/* list of used pages */
 	u64			len;
+	int			coll_index;
+	struct rbd_req_coll	*coll;
+};
+
+struct rbd_req_status {
+	int done;
+	int rc;
+	u64 bytes;
+};
+
+/*
+ * a collection of requests
+ */
+struct rbd_req_coll {
+	int			total;
+	int			num_done;
+	struct kref		kref;
+	struct rbd_req_status	status[0];
 };
 
 struct rbd_snap {
@@ -124,6 +154,9 @@ struct rbd_device {
 	char			pool_name[RBD_MAX_POOL_NAME_LEN];
 	int			poolid;
 
+	struct ceph_osd_event   *watch_event;
+	struct ceph_osd_request *watch_request;
+
 	char                    snap_name[RBD_MAX_SNAP_NAME_LEN];
 	u32 cur_snap;	/* index+1 of current snapshot within snap context
 			   0 - for the head */
@@ -177,6 +210,8 @@ static void rbd_put_dev(struct rbd_device *rbd_dev)
 	put_device(&rbd_dev->dev);
 }
 
+static int __rbd_update_snaps(struct rbd_device *rbd_dev);
+
 static int rbd_open(struct block_device *bdev, fmode_t mode)
 {
 	struct gendisk *disk = bdev->bd_disk;
@@ -211,7 +246,8 @@ static const struct block_device_operations rbd_bd_ops = {
  * Initialize an rbd client instance.
  * We own *opt.
  */
-static struct rbd_client *rbd_client_create(struct ceph_options *opt)
+static struct rbd_client *rbd_client_create(struct ceph_options *opt,
+					    struct rbd_options *rbd_opts)
 {
 	struct rbd_client *rbdc;
 	int ret = -ENOMEM;
@@ -233,6 +269,8 @@ static struct rbd_client *rbd_client_create(struct ceph_options *opt)
 	if (ret < 0)
 		goto out_err;
 
+	rbdc->rbd_opts = rbd_opts;
+
 	spin_lock(&node_lock);
 	list_add_tail(&rbdc->node, &rbd_client_list);
 	spin_unlock(&node_lock);
@@ -267,6 +305,59 @@ static struct rbd_client *__rbd_client_find(struct ceph_options *opt)
 }
 
 /*
+ * mount options
+ */
+enum {
+	Opt_notify_timeout,
+	Opt_last_int,
+	/* int args above */
+	Opt_last_string,
+	/* string args above */
+};
+
+static match_table_t rbdopt_tokens = {
+	{Opt_notify_timeout, "notify_timeout=%d"},
+	/* int args above */
+	/* string args above */
+	{-1, NULL}
+};
+
+static int parse_rbd_opts_token(char *c, void *private)
+{
+	struct rbd_options *rbdopt = private;
+	substring_t argstr[MAX_OPT_ARGS];
+	int token, intval, ret;
+
+	token = match_token((char *)c, rbdopt_tokens, argstr);
+	if (token < 0)
+		return -EINVAL;
+
+	if (token < Opt_last_int) {
+		ret = match_int(&argstr[0], &intval);
+		if (ret < 0) {
+			pr_err("bad mount option arg (not int) "
+			       "at '%s'\n", c);
+			return ret;
+		}
+		dout("got int token %d val %d\n", token, intval);
+	} else if (token > Opt_last_int && token < Opt_last_string) {
+		dout("got string token %d val %s\n", token,
+		     argstr[0].from);
+	} else {
+		dout("got token %d\n", token);
+	}
+
+	switch (token) {
+	case Opt_notify_timeout:
+		rbdopt->notify_timeout = intval;
+		break;
+	default:
+		BUG_ON(token);
+	}
+	return 0;
+}
+
+/*
  * Get a ceph client with specific addr and configuration, if one does
  * not exist create it.
  */
@@ -276,11 +367,18 @@ static int rbd_get_client(struct rbd_device *rbd_dev, const char *mon_addr,
 	struct rbd_client *rbdc;
 	struct ceph_options *opt;
 	int ret;
+	struct rbd_options *rbd_opts;
+
+	rbd_opts = kzalloc(sizeof(*rbd_opts), GFP_KERNEL);
+	if (!rbd_opts)
+		return -ENOMEM;
+
+	rbd_opts->notify_timeout = RBD_NOTIFY_TIMEOUT_DEFAULT;
 
 	ret = ceph_parse_options(&opt, options, mon_addr,
-				 mon_addr + strlen(mon_addr), NULL, NULL);
+				 mon_addr + strlen(mon_addr), parse_rbd_opts_token, rbd_opts);
 	if (ret < 0)
-		return ret;
+		goto done_err;
 
 	spin_lock(&node_lock);
 	rbdc = __rbd_client_find(opt);
@@ -296,13 +394,18 @@ static int rbd_get_client(struct rbd_device *rbd_dev, const char *mon_addr,
 	}
 	spin_unlock(&node_lock);
 
-	rbdc = rbd_client_create(opt);
-	if (IS_ERR(rbdc))
-		return PTR_ERR(rbdc);
+	rbdc = rbd_client_create(opt, rbd_opts);
+	if (IS_ERR(rbdc)) {
+		ret = PTR_ERR(rbdc);
+		goto done_err;
+	}
 
 	rbd_dev->rbd_client = rbdc;
 	rbd_dev->client = rbdc->client;
 	return 0;
+done_err:
+	kfree(rbd_opts);
+	return ret;
 }
 
 /*
@@ -318,6 +421,7 @@ static void rbd_client_release(struct kref *kref)
 	spin_unlock(&node_lock);
 
 	ceph_destroy_client(rbdc->client);
+	kfree(rbdc->rbd_opts);
 	kfree(rbdc);
 }
 
@@ -332,6 +436,17 @@ static void rbd_put_client(struct rbd_device *rbd_dev)
 	rbd_dev->client = NULL;
 }
 
+/*
+ * Destroy requests collection
+ */
+static void rbd_coll_release(struct kref *kref)
+{
+	struct rbd_req_coll *coll =
+		container_of(kref, struct rbd_req_coll, kref);
+
+	dout("rbd_coll_release %p\n", coll);
+	kfree(coll);
+}
 
 /*
  * Create a new header structure, translate header format from the on-disk
@@ -506,6 +621,14 @@ static u64 rbd_get_segment(struct rbd_image_header *header,
 	return len;
 }
 
+static int rbd_get_num_segments(struct rbd_image_header *header,
+				u64 ofs, u64 len)
+{
+	u64 start_seg = ofs >> header->obj_order;
+	u64 end_seg = (ofs + len - 1) >> header->obj_order;
+	return end_seg - start_seg + 1;
+}
+
 /*
  * bio helpers
  */
@@ -651,6 +774,50 @@ static void rbd_destroy_ops(struct ceph_osd_req_op *ops)
 	kfree(ops);
 }
 
+static void rbd_coll_end_req_index(struct request *rq,
+				   struct rbd_req_coll *coll,
+				   int index,
+				   int ret, u64 len)
+{
+	struct request_queue *q;
+	int min, max, i;
+
+	dout("rbd_coll_end_req_index %p index %d ret %d len %lld\n",
+	     coll, index, ret, len);
+
+	if (!rq)
+		return;
+
+	if (!coll) {
+		blk_end_request(rq, ret, len);
+		return;
+	}
+
+	q = rq->q;
+
+	spin_lock_irq(q->queue_lock);
+	coll->status[index].done = 1;
+	coll->status[index].rc = ret;
+	coll->status[index].bytes = len;
+	max = min = coll->num_done;
+	while (max < coll->total && coll->status[max].done)
+		max++;
+
+	for (i = min; i<max; i++) {
+		__blk_end_request(rq, coll->status[i].rc,
+				  coll->status[i].bytes);
+		coll->num_done++;
+		kref_put(&coll->kref, rbd_coll_release);
+	}
+	spin_unlock_irq(q->queue_lock);
+}
+
+static void rbd_coll_end_req(struct rbd_request *req,
+			     int ret, u64 len)
+{
+	rbd_coll_end_req_index(req->rq, req->coll, req->coll_index, ret, len);
+}
+
 /*
  * Send ceph osd request
  */
@@ -665,8 +832,12 @@ static int rbd_do_request(struct request *rq,
 			  int flags,
 			  struct ceph_osd_req_op *ops,
 			  int num_reply,
+			  struct rbd_req_coll *coll,
+			  int coll_index,
 			  void (*rbd_cb)(struct ceph_osd_request *req,
-					 struct ceph_msg *msg))
+					 struct ceph_msg *msg),
+			  struct ceph_osd_request **linger_req,
+			  u64 *ver)
 {
 	struct ceph_osd_request *req;
 	struct ceph_file_layout *layout;
@@ -677,12 +848,20 @@ static int rbd_do_request(struct request *rq,
 	struct ceph_osd_request_head *reqhead;
 	struct rbd_image_header *header = &dev->header;
 
-	ret = -ENOMEM;
 	req_data = kzalloc(sizeof(*req_data), GFP_NOIO);
-	if (!req_data)
-		goto done;
+	if (!req_data) {
+		if (coll)
+			rbd_coll_end_req_index(rq, coll, coll_index,
+					       -ENOMEM, len);
+		return -ENOMEM;
+	}
+
+	if (coll) {
+		req_data->coll = coll;
+		req_data->coll_index = coll_index;
+	}
 
-	dout("rbd_do_request len=%lld ofs=%lld\n", len, ofs);
+	dout("rbd_do_request obj=%s ofs=%lld len=%lld\n", obj, len, ofs);
 
 	down_read(&header->snap_rwsem);
 
@@ -691,9 +870,9 @@ static int rbd_do_request(struct request *rq,
 				      ops,
 				      false,
 				      GFP_NOIO, pages, bio);
-	if (IS_ERR(req)) {
+	if (!req) {
 		up_read(&header->snap_rwsem);
-		ret = PTR_ERR(req);
+		ret = -ENOMEM;
 		goto done_pages;
 	}
 
@@ -729,12 +908,21 @@ static int rbd_do_request(struct request *rq,
 				req->r_oid, req->r_oid_len);
 	up_read(&header->snap_rwsem);
 
+	if (linger_req) {
+		ceph_osdc_set_request_linger(&dev->client->osdc, req);
+		*linger_req = req;
+	}
+
 	ret = ceph_osdc_start_request(&dev->client->osdc, req, false);
 	if (ret < 0)
 		goto done_err;
 
 	if (!rbd_cb) {
 		ret = ceph_osdc_wait_request(&dev->client->osdc, req);
+		if (ver)
+			*ver = le64_to_cpu(req->r_reassert_version.version);
+		dout("reassert_ver=%lld\n",
+		     le64_to_cpu(req->r_reassert_version.version));
 		ceph_osdc_put_request(req);
 	}
 	return ret;
@@ -743,10 +931,8 @@ done_err:
 	bio_chain_put(req_data->bio);
 	ceph_osdc_put_request(req);
 done_pages:
+	rbd_coll_end_req(req_data, ret, len);
 	kfree(req_data);
-done:
-	if (rq)
-		blk_end_request(rq, ret, len);
 	return ret;
 }
 
@@ -780,7 +966,7 @@ static void rbd_req_cb(struct ceph_osd_request *req, struct ceph_msg *msg)
 		bytes = req_data->len;
 	}
 
-	blk_end_request(req_data->rq, rc, bytes);
+	rbd_coll_end_req(req_data, rc, bytes);
 
 	if (req_data->bio)
 		bio_chain_put(req_data->bio);
@@ -789,6 +975,11 @@ static void rbd_req_cb(struct ceph_osd_request *req, struct ceph_msg *msg)
 	kfree(req_data);
 }
 
+static void rbd_simple_req_cb(struct ceph_osd_request *req, struct ceph_msg *msg)
+{
+	ceph_osdc_put_request(req);
+}
+
 /*
  * Do a synchronous ceph osd operation
  */
@@ -801,7 +992,9 @@ static int rbd_req_sync_op(struct rbd_device *dev,
 			   int num_reply,
 			   const char *obj,
 			   u64 ofs, u64 len,
-			   char *buf)
+			   char *buf,
+			   struct ceph_osd_request **linger_req,
+			   u64 *ver)
 {
 	int ret;
 	struct page **pages;
@@ -833,7 +1026,9 @@ static int rbd_req_sync_op(struct rbd_device *dev,
 			  flags,
 			  ops,
 			  2,
-			  NULL);
+			  NULL, 0,
+			  NULL,
+			  linger_req, ver);
 	if (ret < 0)
 		goto done_ops;
 
@@ -857,7 +1052,9 @@ static int rbd_do_op(struct request *rq,
 		     u64 snapid,
 		     int opcode, int flags, int num_reply,
 		     u64 ofs, u64 len,
-		     struct bio *bio)
+		     struct bio *bio,
+		     struct rbd_req_coll *coll,
+		     int coll_index)
 {
 	char *seg_name;
 	u64 seg_ofs;
@@ -893,7 +1090,10 @@ static int rbd_do_op(struct request *rq,
 			     flags,
 			     ops,
 			     num_reply,
-			     rbd_req_cb);
+			     coll, coll_index,
+			     rbd_req_cb, 0, NULL);
+
+	rbd_destroy_ops(ops);
 done:
 	kfree(seg_name);
 	return ret;
@@ -906,13 +1106,15 @@ static int rbd_req_write(struct request *rq,
 			 struct rbd_device *rbd_dev,
 			 struct ceph_snap_context *snapc,
 			 u64 ofs, u64 len,
-			 struct bio *bio)
+			 struct bio *bio,
+			 struct rbd_req_coll *coll,
+			 int coll_index)
 {
 	return rbd_do_op(rq, rbd_dev, snapc, CEPH_NOSNAP,
 			 CEPH_OSD_OP_WRITE,
 			 CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
 			 2,
-			 ofs, len, bio);
+			 ofs, len, bio, coll, coll_index);
 }
 
 /*
@@ -922,14 +1124,16 @@ static int rbd_req_read(struct request *rq,
 			 struct rbd_device *rbd_dev,
 			 u64 snapid,
 			 u64 ofs, u64 len,
-			 struct bio *bio)
+			 struct bio *bio,
+			 struct rbd_req_coll *coll,
+			 int coll_index)
 {
 	return rbd_do_op(rq, rbd_dev, NULL,
 			 (snapid ? snapid : CEPH_NOSNAP),
 			 CEPH_OSD_OP_READ,
 			 CEPH_OSD_FLAG_READ,
 			 2,
-			 ofs, len, bio);
+			 ofs, len, bio, coll, coll_index);
 }
 
 /*
@@ -940,18 +1144,177 @@ static int rbd_req_sync_read(struct rbd_device *dev,
 			  u64 snapid,
 			  const char *obj,
 			  u64 ofs, u64 len,
-			  char *buf)
+			  char *buf,
+			  u64 *ver)
 {
 	return rbd_req_sync_op(dev, NULL,
 			       (snapid ? snapid : CEPH_NOSNAP),
 			       CEPH_OSD_OP_READ,
 			       CEPH_OSD_FLAG_READ,
 			       NULL,
-			       1, obj, ofs, len, buf);
+			       1, obj, ofs, len, buf, NULL, ver);
 }
 
 /*
- * Request sync osd read
+ * Request sync osd watch
+ */
+static int rbd_req_sync_notify_ack(struct rbd_device *dev,
+				   u64 ver,
+				   u64 notify_id,
+				   const char *obj)
+{
+	struct ceph_osd_req_op *ops;
+	struct page **pages = NULL;
+	int ret;
+
+	ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_NOTIFY_ACK, 0);
+	if (ret < 0)
+		return ret;
+
+	ops[0].watch.ver = cpu_to_le64(dev->header.obj_version);
+	ops[0].watch.cookie = notify_id;
+	ops[0].watch.flag = 0;
+
+	ret = rbd_do_request(NULL, dev, NULL, CEPH_NOSNAP,
+			  obj, 0, 0, NULL,
+			  pages, 0,
+			  CEPH_OSD_FLAG_READ,
+			  ops,
+			  1,
+			  NULL, 0,
+			  rbd_simple_req_cb, 0, NULL);
+
+	rbd_destroy_ops(ops);
+	return ret;
+}
+
+static void rbd_watch_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
+{
+	struct rbd_device *dev = (struct rbd_device *)data;
+	if (!dev)
+		return;
+
+	dout("rbd_watch_cb %s notify_id=%lld opcode=%d\n", dev->obj_md_name,
+		notify_id, (int)opcode);
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+	__rbd_update_snaps(dev);
+	mutex_unlock(&ctl_mutex);
+
+	rbd_req_sync_notify_ack(dev, ver, notify_id, dev->obj_md_name);
+}
+
+/*
+ * Request sync osd watch
+ */
+static int rbd_req_sync_watch(struct rbd_device *dev,
+			      const char *obj,
+			      u64 ver)
+{
+	struct ceph_osd_req_op *ops;
+	struct ceph_osd_client *osdc = &dev->client->osdc;
+
+	int ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_WATCH, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = ceph_osdc_create_event(osdc, rbd_watch_cb, 0,
+				     (void *)dev, &dev->watch_event);
+	if (ret < 0)
+		goto fail;
+
+	ops[0].watch.ver = cpu_to_le64(ver);
+	ops[0].watch.cookie = cpu_to_le64(dev->watch_event->cookie);
+	ops[0].watch.flag = 1;
+
+	ret = rbd_req_sync_op(dev, NULL,
+			      CEPH_NOSNAP,
+			      0,
+			      CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
+			      ops,
+			      1, obj, 0, 0, NULL,
+			      &dev->watch_request, NULL);
+
+	if (ret < 0)
+		goto fail_event;
+
+	rbd_destroy_ops(ops);
+	return 0;
+
+fail_event:
+	ceph_osdc_cancel_event(dev->watch_event);
+	dev->watch_event = NULL;
+fail:
+	rbd_destroy_ops(ops);
+	return ret;
+}
+
+struct rbd_notify_info {
+	struct rbd_device *dev;
+};
+
+static void rbd_notify_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
+{
+	struct rbd_device *dev = (struct rbd_device *)data;
+	if (!dev)
+		return;
+
+	dout("rbd_notify_cb %s notify_id=%lld opcode=%d\n", dev->obj_md_name,
+		notify_id, (int)opcode);
+}
+
+/*
+ * Request sync osd notify
+ */
+static int rbd_req_sync_notify(struct rbd_device *dev,
+		          const char *obj)
+{
+	struct ceph_osd_req_op *ops;
+	struct ceph_osd_client *osdc = &dev->client->osdc;
+	struct ceph_osd_event *event;
+	struct rbd_notify_info info;
+	int payload_len = sizeof(u32) + sizeof(u32);
+	int ret;
+
+	ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_NOTIFY, payload_len);
+	if (ret < 0)
+		return ret;
+
+	info.dev = dev;
+
+	ret = ceph_osdc_create_event(osdc, rbd_notify_cb, 1,
+				     (void *)&info, &event);
+	if (ret < 0)
+		goto fail;
+
+	ops[0].watch.ver = 1;
+	ops[0].watch.flag = 1;
+	ops[0].watch.cookie = event->cookie;
+	ops[0].watch.prot_ver = RADOS_NOTIFY_VER;
+	ops[0].watch.timeout = 12;
+
+	ret = rbd_req_sync_op(dev, NULL,
+			       CEPH_NOSNAP,
+			       0,
+			       CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
+			       ops,
+			       1, obj, 0, 0, NULL, NULL, NULL);
+	if (ret < 0)
+		goto fail_event;
+
+	ret = ceph_osdc_wait_event(event, CEPH_OSD_TIMEOUT_DEFAULT);
+	dout("ceph_osdc_wait_event returned %d\n", ret);
+	rbd_destroy_ops(ops);
+	return 0;
+
+fail_event:
+	ceph_osdc_cancel_event(event);
+fail:
+	rbd_destroy_ops(ops);
+	return ret;
+}
+
+/*
+ * Request sync osd rollback
  */
 static int rbd_req_sync_rollback_obj(struct rbd_device *dev,
 				     u64 snapid,
@@ -969,13 +1332,10 @@ static int rbd_req_sync_rollback_obj(struct rbd_device *dev,
 			       0,
 			       CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
 			       ops,
-			       1, obj, 0, 0, NULL);
+			       1, obj, 0, 0, NULL, NULL, NULL);
 
 	rbd_destroy_ops(ops);
 
-	if (ret < 0)
-		return ret;
-
 	return ret;
 }
 
@@ -987,7 +1347,8 @@ static int rbd_req_sync_exec(struct rbd_device *dev,
 			     const char *cls,
 			     const char *method,
 			     const char *data,
-			     int len)
+			     int len,
+			     u64 *ver)
 {
 	struct ceph_osd_req_op *ops;
 	int cls_len = strlen(cls);
@@ -1010,7 +1371,7 @@ static int rbd_req_sync_exec(struct rbd_device *dev,
 			       0,
 			       CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
 			       ops,
-			       1, obj, 0, 0, NULL);
+			       1, obj, 0, 0, NULL, NULL, ver);
 
 	rbd_destroy_ops(ops);
 
@@ -1018,6 +1379,20 @@ static int rbd_req_sync_exec(struct rbd_device *dev,
 	return ret;
 }
 
+static struct rbd_req_coll *rbd_alloc_coll(int num_reqs)
+{
+	struct rbd_req_coll *coll =
+			kzalloc(sizeof(struct rbd_req_coll) +
+			        sizeof(struct rbd_req_status) * num_reqs,
+				GFP_ATOMIC);
+
+	if (!coll)
+		return NULL;
+	coll->total = num_reqs;
+	kref_init(&coll->kref);
+	return coll;
+}
+
 /*
  * block device queue callback
  */
@@ -1035,6 +1410,8 @@ static void rbd_rq_fn(struct request_queue *q)
 		bool do_write;
 		int size, op_size = 0;
 		u64 ofs;
+		int num_segs, cur_seg = 0;
+		struct rbd_req_coll *coll;
 
 		/* peek at request from block layer */
 		if (!rq)
@@ -1065,6 +1442,14 @@ static void rbd_rq_fn(struct request_queue *q)
 		     do_write ? "write" : "read",
 		     size, blk_rq_pos(rq) * 512ULL);
 
+		num_segs = rbd_get_num_segments(&rbd_dev->header, ofs, size);
+		coll = rbd_alloc_coll(num_segs);
+		if (!coll) {
+			spin_lock_irq(q->queue_lock);
+			__blk_end_request_all(rq, -ENOMEM);
+			goto next;
+		}
+
 		do {
 			/* a bio clone to be passed down to OSD req */
 			dout("rq->bio->bi_vcnt=%d\n", rq->bio->bi_vcnt);
@@ -1072,35 +1457,41 @@ static void rbd_rq_fn(struct request_queue *q)
 						  rbd_dev->header.block_name,
 						  ofs, size,
 						  NULL, NULL);
+			kref_get(&coll->kref);
 			bio = bio_chain_clone(&rq_bio, &next_bio, &bp,
 					      op_size, GFP_ATOMIC);
 			if (!bio) {
-				spin_lock_irq(q->queue_lock);
-				__blk_end_request_all(rq, -ENOMEM);
-				goto next;
+				rbd_coll_end_req_index(rq, coll, cur_seg,
+						       -ENOMEM, op_size);
+				goto next_seg;
 			}
 
+
 			/* init OSD command: write or read */
 			if (do_write)
 				rbd_req_write(rq, rbd_dev,
 					      rbd_dev->header.snapc,
 					      ofs,
-					      op_size, bio);
+					      op_size, bio,
+					      coll, cur_seg);
 			else
 				rbd_req_read(rq, rbd_dev,
 					     cur_snap_id(rbd_dev),
 					     ofs,
-					     op_size, bio);
+					     op_size, bio,
+					     coll, cur_seg);
 
+next_seg:
 			size -= op_size;
 			ofs += op_size;
 
+			cur_seg++;
 			rq_bio = next_bio;
 		} while (size > 0);
+		kref_put(&coll->kref, rbd_coll_release);
 
 		if (bp)
 			bio_pair_release(bp);
-
 		spin_lock_irq(q->queue_lock);
 next:
 		rq = blk_fetch_request(q);
@@ -1156,6 +1547,7 @@ static int rbd_read_header(struct rbd_device *rbd_dev,
 	struct rbd_image_header_ondisk *dh;
 	int snap_count = 0;
 	u64 snap_names_len = 0;
+	u64 ver;
 
 	while (1) {
 		int len = sizeof(*dh) +
@@ -1171,7 +1563,7 @@ static int rbd_read_header(struct rbd_device *rbd_dev,
 				       NULL, CEPH_NOSNAP,
 				       rbd_dev->obj_md_name,
 				       0, len,
-				       (char *)dh);
+				       (char *)dh, &ver);
 		if (rc < 0)
 			goto out_dh;
 
@@ -1188,6 +1580,7 @@ static int rbd_read_header(struct rbd_device *rbd_dev,
 		}
 		break;
 	}
+	header->obj_version = ver;
 
 out_dh:
 	kfree(dh);
@@ -1205,6 +1598,7 @@ static int rbd_header_add_snap(struct rbd_device *dev,
 	u64 new_snapid;
 	int ret;
 	void *data, *data_start, *data_end;
+	u64 ver;
 
 	/* we should create a snapshot only if we're pointing at the head */
 	if (dev->cur_snap)
@@ -1227,7 +1621,7 @@ static int rbd_header_add_snap(struct rbd_device *dev,
 	ceph_encode_64_safe(&data, data_end, new_snapid, bad);
 
 	ret = rbd_req_sync_exec(dev, dev->obj_md_name, "rbd", "snap_add",
-				data_start, data - data_start);
+				data_start, data - data_start, &ver);
 
 	kfree(data_start);
 
@@ -1259,6 +1653,7 @@ static int __rbd_update_snaps(struct rbd_device *rbd_dev)
 	int ret;
 	struct rbd_image_header h;
 	u64 snap_seq;
+	int follow_seq = 0;
 
 	ret = rbd_read_header(rbd_dev, &h);
 	if (ret < 0)
@@ -1267,6 +1662,11 @@ static int __rbd_update_snaps(struct rbd_device *rbd_dev)
 	down_write(&rbd_dev->header.snap_rwsem);
 
 	snap_seq = rbd_dev->header.snapc->seq;
+	if (rbd_dev->header.total_snaps &&
+	    rbd_dev->header.snapc->snaps[0] == snap_seq)
+		/* pointing at the head, will need to follow that
+		   if head moves */
+		follow_seq = 1;
 
 	kfree(rbd_dev->header.snapc);
 	kfree(rbd_dev->header.snap_names);
@@ -1277,7 +1677,10 @@ static int __rbd_update_snaps(struct rbd_device *rbd_dev)
 	rbd_dev->header.snap_names = h.snap_names;
 	rbd_dev->header.snap_names_len = h.snap_names_len;
 	rbd_dev->header.snap_sizes = h.snap_sizes;
-	rbd_dev->header.snapc->seq = snap_seq;
+	if (follow_seq)
+		rbd_dev->header.snapc->seq = rbd_dev->header.snapc->snaps[0];
+	else
+		rbd_dev->header.snapc->seq = snap_seq;
 
 	ret = __rbd_init_snaps_header(rbd_dev);
 
@@ -1699,7 +2102,28 @@ static void rbd_bus_del_dev(struct rbd_device *rbd_dev)
 	device_unregister(&rbd_dev->dev);
 }
 
-static ssize_t rbd_add(struct bus_type *bus, const char *buf, size_t count)
+static int rbd_init_watch_dev(struct rbd_device *rbd_dev)
+{
+	int ret, rc;
+
+	do {
+		ret = rbd_req_sync_watch(rbd_dev, rbd_dev->obj_md_name,
+					 rbd_dev->header.obj_version);
+		if (ret == -ERANGE) {
+			mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+			rc = __rbd_update_snaps(rbd_dev);
+			mutex_unlock(&ctl_mutex);
+			if (rc < 0)
+				return rc;
+		}
+	} while (ret == -ERANGE);
+
+	return ret;
+}
+
+static ssize_t rbd_add(struct bus_type *bus,
+		       const char *buf,
+		       size_t count)
 {
 	struct ceph_osd_client *osdc;
 	struct rbd_device *rbd_dev;
@@ -1797,6 +2221,10 @@ static ssize_t rbd_add(struct bus_type *bus, const char *buf, size_t count)
 	if (rc)
 		goto err_out_bus;
 
+	rc = rbd_init_watch_dev(rbd_dev);
+	if (rc)
+		goto err_out_bus;
+
 	return count;
 
 err_out_bus:
@@ -1849,6 +2277,12 @@ static void rbd_dev_release(struct device *dev)
 	struct rbd_device *rbd_dev =
 			container_of(dev, struct rbd_device, dev);
 
+	if (rbd_dev->watch_request)
+		ceph_osdc_unregister_linger_request(&rbd_dev->client->osdc,
+						    rbd_dev->watch_request);
+	if (rbd_dev->watch_event)
+		ceph_osdc_cancel_event(rbd_dev->watch_event);
+
 	rbd_put_client(rbd_dev);
 
 	/* clean up and free blkdev */
@@ -1914,14 +2348,24 @@ static ssize_t rbd_snap_add(struct device *dev,
 	ret = rbd_header_add_snap(rbd_dev,
 				  name, GFP_KERNEL);
 	if (ret < 0)
-		goto done_unlock;
+		goto err_unlock;
 
 	ret = __rbd_update_snaps(rbd_dev);
 	if (ret < 0)
-		goto done_unlock;
+		goto err_unlock;
+
+	/* shouldn't hold ctl_mutex when notifying.. notify might
+	   trigger a watch callback that would need to get that mutex */
+	mutex_unlock(&ctl_mutex);
+
+	/* make a best effort, don't error if failed */
+	rbd_req_sync_notify(rbd_dev, rbd_dev->obj_md_name);
 
 	ret = count;
-done_unlock:
+	kfree(name);
+	return ret;
+
+err_unlock:
 	mutex_unlock(&ctl_mutex);
 	kfree(name);
 	return ret;