libceph: support for sending notifies

Implement ceph_osdc_notify() for sending notifies.

Due to the fact that the current messenger can't do read-in into
pagelists (it can only do write-out from them), I had to go with a page
vector for a NOTIFY_COMPLETE payload, for now.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

include/linux/ceph/osd_client.h

@@ -114,6 +114,11 @@ struct ceph_osd_req_op {
 		struct {
 			struct ceph_osd_data request_data;
 		} notify_ack;
+		struct {
+			u64 cookie;
+			struct ceph_osd_data request_data;
+			struct ceph_osd_data response_data;
+		} notify;
 		struct {
 			u64 expected_object_size;
 			u64 expected_write_size;
@@ -202,6 +207,7 @@ struct ceph_osd_linger_request {
 	struct ceph_osd_client *osdc;
 	u64 linger_id;
 	bool committed;
+	bool is_watch;                  /* watch or notify */
 
 	struct ceph_osd *osd;
 	struct ceph_osd_request *reg_req;
@@ -220,14 +226,20 @@ struct ceph_osd_linger_request {
 	struct list_head scan_item;
 
 	struct completion reg_commit_wait;
+	struct completion notify_finish_wait;
 	int reg_commit_error;
+	int notify_finish_error;
 	int last_error;
 
 	u32 register_gen;
+	u64 notify_id;
 
 	rados_watchcb2_t wcb;
 	rados_watcherrcb_t errcb;
 	void *data;
+
+	struct page ***preply_pages;
+	size_t *preply_len;
 };
 
 struct ceph_osd_client {
@@ -397,5 +409,13 @@ int ceph_osdc_notify_ack(struct ceph_osd_client *osdc,
 			 u64 cookie,
 			 void *payload,
 			 size_t payload_len);
+int ceph_osdc_notify(struct ceph_osd_client *osdc,
+		     struct ceph_object_id *oid,
+		     struct ceph_object_locator *oloc,
+		     void *payload,
+		     size_t payload_len,
+		     u32 timeout,
+		     struct page ***preply_pages,
+		     size_t *preply_len);
 #endif
 

include/linux/ceph/rados.h

@@ -476,6 +476,9 @@ struct ceph_osd_op {
 			__u8 op;	/* CEPH_OSD_WATCH_OP_* */
 			__le32 gen;     /* registration generation */
 		} __attribute__ ((packed)) watch;
+		struct {
+			__le64 cookie;
+		} __attribute__ ((packed)) notify;
 		struct {
 			__le64 offset, length;
 			__le64 src_offset;

net/ceph/debugfs.c

@@ -206,8 +206,9 @@ static void dump_linger_request(struct seq_file *s,
 	seq_printf(s, "%llu\t", lreq->linger_id);
 	dump_target(s, &lreq->t);
 
-	seq_printf(s, "\t%u\t%s/%d\n", lreq->register_gen,
-		   lreq->committed ? "C" : "", lreq->last_error);
+	seq_printf(s, "\t%u\t%s%s/%d\n", lreq->register_gen,
+		   lreq->is_watch ? "W" : "N", lreq->committed ? "C" : "",
+		   lreq->last_error);
 }
 
 static void dump_linger_requests(struct seq_file *s, struct ceph_osd *osd)