libceph: introduce and start using oid abstraction

In preparation for tiering support, which would require having two
(base and target) object names for each osd request and also copying
those names around, introduce struct ceph_object_id (oid) and a couple
helpers to facilitate those copies and encapsulate the fact that object
name is not necessarily a NUL-terminated string.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

drivers/block/rbd.c

@@ -1809,10 +1809,7 @@ static struct ceph_osd_request *rbd_osd_req_create(
 	osd_req->r_priv = obj_request;
 
 	osd_req->r_oloc.pool = ceph_file_layout_pg_pool(rbd_dev->layout);
-
-	osd_req->r_oid_len = strlen(obj_request->object_name);
-	rbd_assert(osd_req->r_oid_len < sizeof (osd_req->r_oid));
-	memcpy(osd_req->r_oid, obj_request->object_name, osd_req->r_oid_len);
+	ceph_oid_set_name(&osd_req->r_oid, obj_request->object_name);
 
 	return osd_req;
 }
@@ -1850,10 +1847,7 @@ rbd_osd_req_create_copyup(struct rbd_obj_request *obj_request)
 	osd_req->r_priv = obj_request;
 
 	osd_req->r_oloc.pool = ceph_file_layout_pg_pool(rbd_dev->layout);
-
-	osd_req->r_oid_len = strlen(obj_request->object_name);
-	rbd_assert(osd_req->r_oid_len < sizeof (osd_req->r_oid));
-	memcpy(osd_req->r_oid, obj_request->object_name, osd_req->r_oid_len);
+	ceph_oid_set_name(&osd_req->r_oid, obj_request->object_name);
 
 	return osd_req;
 }

include/linux/ceph/osd_client.h

@@ -12,12 +12,6 @@
 #include <linux/ceph/auth.h>
 #include <linux/ceph/pagelist.h>
 
-/* 
- * Maximum object name size 
- * (must be at least as big as RBD_MAX_MD_NAME_LEN -- currently 100) 
- */
-#define CEPH_MAX_OID_NAME_LEN 100
-
 struct ceph_msg;
 struct ceph_snap_context;
 struct ceph_osd_request;
@@ -160,9 +154,8 @@ struct ceph_osd_request {
 	void *r_priv;			      /* ditto */
 
 	struct ceph_object_locator r_oloc;
+	struct ceph_object_id r_oid;
 
-	char              r_oid[CEPH_MAX_OID_NAME_LEN];      /* object name */
-	int               r_oid_len;
 	u64               r_snapid;
 	unsigned long     r_stamp;            /* send OR check time */
 

include/linux/ceph/osdmap.h

@@ -43,6 +43,18 @@ struct ceph_object_locator {
 	s64 pool;
 };
 
+/*
+ * Maximum supported by kernel client object name length
+ *
+ * (probably outdated: must be >= RBD_MAX_MD_NAME_LEN -- currently 100)
+ */
+#define CEPH_MAX_OID_NAME_LEN 100
+
+struct ceph_object_id {
+	char name[CEPH_MAX_OID_NAME_LEN];
+	int name_len;
+};
+
 struct ceph_pg_mapping {
 	struct rb_node node;
 	struct ceph_pg pgid;
@@ -72,6 +84,30 @@ struct ceph_osdmap {
 	struct crush_map *crush;
 };
 
+static inline void ceph_oid_set_name(struct ceph_object_id *oid,
+				     const char *name)
+{
+	int len;
+
+	len = strlen(name);
+	if (len > sizeof(oid->name)) {
+		WARN(1, "ceph_oid_set_name '%s' len %d vs %zu, truncating\n",
+		     name, len, sizeof(oid->name));
+		len = sizeof(oid->name);
+	}
+
+	memcpy(oid->name, name, len);
+	oid->name_len = len;
+}
+
+static inline void ceph_oid_copy(struct ceph_object_id *dest,
+				 struct ceph_object_id *src)
+{
+	BUG_ON(src->name_len > sizeof(dest->name));
+	memcpy(dest->name, src->name, src->name_len);
+	dest->name_len = src->name_len;
+}
+
 static inline int ceph_osd_is_up(struct ceph_osdmap *map, int osd)
 {
 	return (osd < map->max_osd) && (map->osd_state[osd] & CEPH_OSD_UP);

net/ceph/debugfs.c

@@ -132,7 +132,8 @@ static int osdc_show(struct seq_file *s, void *pp)
 			   req->r_osd ? req->r_osd->o_osd : -1,
 			   req->r_pgid.pool, req->r_pgid.seed);
 
-		seq_printf(s, "%.*s", req->r_oid_len, req->r_oid);
+		seq_printf(s, "%.*s", req->r_oid.name_len,
+			   req->r_oid.name);
 
 		if (req->r_reassert_version.epoch)
 			seq_printf(s, "\t%u'%llu",

net/ceph/osd_client.c

@@ -765,9 +765,9 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 
 	req->r_oloc.pool = ceph_file_layout_pg_pool(*layout);
 
-	snprintf(req->r_oid, sizeof(req->r_oid), "%llx.%08llx",
-		vino.ino, objnum);
-	req->r_oid_len = strlen(req->r_oid);
+	snprintf(req->r_oid.name, sizeof(req->r_oid.name),
+		 "%llx.%08llx", vino.ino, objnum);
+	req->r_oid.name_len = strlen(req->r_oid.name);
 
 	return req;
 }
@@ -1269,7 +1269,7 @@ static int __map_request(struct ceph_osd_client *osdc,
 	bool was_paused;
 
 	dout("map_request %p tid %lld\n", req, req->r_tid);
-	err = ceph_calc_ceph_pg(&pgid, req->r_oid, osdc->osdmap,
+	err = ceph_calc_ceph_pg(&pgid, req->r_oid.name, osdc->osdmap,
 				req->r_oloc.pool);
 	if (err) {
 		list_move(&req->r_req_lru_item, &osdc->req_notarget);
@@ -2118,10 +2118,11 @@ void ceph_osdc_build_request(struct ceph_osd_request *req, u64 off,
 	ceph_encode_32(&p, -1);  /* preferred */
 
 	/* oid */
-	ceph_encode_32(&p, req->r_oid_len);
-	memcpy(p, req->r_oid, req->r_oid_len);
-	dout("oid '%.*s' len %d\n", req->r_oid_len, req->r_oid, req->r_oid_len);
-	p += req->r_oid_len;
+	ceph_encode_32(&p, req->r_oid.name_len);
+	memcpy(p, req->r_oid.name, req->r_oid.name_len);
+	dout("oid '%.*s' len %d\n", req->r_oid.name_len,
+	     req->r_oid.name, req->r_oid.name_len);
+	p += req->r_oid.name_len;
 
 	/* ops--can imply data */
 	ceph_encode_16(&p, (u16)req->r_num_ops);