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diff --git a/doc/dev/osd_internals/refcount.rst b/doc/dev/osd_internals/refcount.rst new file mode 100644 index 000000000..4d75ae019 --- /dev/null +++ b/doc/dev/osd_internals/refcount.rst @@ -0,0 +1,45 @@ +======== +Refcount +======== + + +Introduction +============ + +Dedupliation, as described in ../deduplication.rst, needs a way to +maintain a target pool of deduplicated chunks with atomic ref +refcounting. To that end, there exists an osd object class +refcount responsible for using the object class machinery to +maintain refcounts on deduped chunks and ultimately remove them +as the refcount hits 0. + +Class Interface +=============== + +See cls/refcount/cls_refcount_client* + +* cls_refcount_get + + Atomically increments the refcount with specified tag :: + + void cls_refcount_get(librados::ObjectWriteOperation& op, const string& tag, bool implicit_ref = false); + +* cls_refcount_put + + Atomically decrements the refcount specified by passed tag :: + + void cls_refcount_put(librados::ObjectWriteOperation& op, const string& tag, bool implicit_ref = false); + +* cls_refcount_Set + + Atomically sets the set of refcounts with passed list of tags :: + + void cls_refcount_set(librados::ObjectWriteOperation& op, list<string>& refs); + +* cls_refcount_read + + Dumps the current set of ref tags for the object :: + + int cls_refcount_read(librados::IoCtx& io_ctx, string& oid, list<string> *refs, bool implicit_ref = false); + + |