os/ObjectStore: clarify clone_range semantics

Signed-off-by: Sage Weil <sage@redhat.com>

diff --git a/src/os/ObjectStore.h b/src/os/ObjectStore.h
index c3e3fa5ba498635e8fca95057826c43ccac2101c..f714e771c89f82b7672653a99577cbdc60dbcfcf 100644 (file)
--- a/src/os/ObjectStore.h
+++ b/src/os/ObjectStore.h
@@ -1338,6 +1338,11 @@ public:
      * The data portion of the destination object receives a copy of a
      * portion of the data from the source object. None of the other
      * three parts of an object is copied from the source.
+     *
+     * The destination object size may be extended to the dstoff + len.
+     *
+     * The source range *must* overlap with the source object data. If it does
+     * not the result is undefined.
      */
     void clone_range(const coll_t& cid, const ghobject_t& oid, ghobject_t noid,
                     uint64_t srcoff, uint64_t srclen, uint64_t dstoff) {