rbd: use semicolon to separate options from the pool/image spec

This format will better support future expansion of additional config
option overrides.

README.md

@@ -96,14 +96,14 @@ o- backstores .......................................................... [...]
 
 /backstores> cd user:rbd 
 
-/backstores/user:rbd> create cfgstring=pool/rbd1/osd_op_timeout=30 name=rbd0 size=1G
+/backstores/user:rbd> create cfgstring=pool/rbd1;osd_op_timeout=30 name=rbd0 size=1G
 Created user-backed storage object rbd0 size 1073741824.
 
 
 Note that the cfgstring is handler specific. The format is:
 
 (osd_op_timeout is optional and N is in seconds)
-rbd: /pool_name/image_name/osd_op_timeout=N
+rbd: /pool_name/image_name[;osd_op_timeout=N]
 qcow: /path_to_file
 glfs: /volume@hostname/filename
 

rbd.c

@@ -548,7 +548,7 @@ static int tcmu_rbd_open(struct tcmu_device *dev)
 		goto free_config;
 	}
 
-	name = strtok(NULL, "/");
+	name = strtok(NULL, ";");
 	if (!name) {
 		tcmu_dev_err(dev, "Could not get image name\n");
 		ret = -EINVAL;
@@ -563,7 +563,7 @@ static int tcmu_rbd_open(struct tcmu_device *dev)
 	}
 
 	/* The next options are optional */
-	next_opt = strtok(NULL, "/");
+	next_opt = strtok(NULL, ";");
 	if (next_opt) {
 		if (!strncmp(next_opt, "osd_op_timeout=", 15)) {
 			state->osd_op_timeout = strdup(next_opt + 15);