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>

1 files changed, 36 insertions, 0 deletions

diff --git a/include/linux/ceph/osdmap.h b/include/linux/ceph/osdmap.h
index f2679c38462..c85f7d43b86 100644
--- a/include/linux/ceph/osdmap.h
+++ b/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+ * (probably outdated: must be 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);