From 7eb287308c5f19be5e130e3d3511eaca8242eed4 Mon Sep 17 00:00:00 2001
From: Samuel Just <samuel.just@dreamhost.com>
Date: Tue, 20 Dec 2011 16:52:38 -0800
Subject: [PATCH] PG: add some documentation

Signed-off-by: Samuel Just <samuel.just@dreamhost.com>
---
 src/osd/PG.cc | 8 ++++++++
 src/osd/PG.h  | 9 +++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/osd/PG.cc b/src/osd/PG.cc
index 33599002d7641..ebb5dfb109f70 100644
--- a/src/osd/PG.cc
+++ b/src/osd/PG.cc
@@ -880,6 +880,14 @@ void PG::clear_primary_state()
   osd->snap_trim_wq.dequeue(this);
 }
 
+/**
+ * find_best_info
+ *
+ * Returns an iterator to the best info in infos sorted by:
+ *  1) Prefer newer last_update
+ *  2) Prefer longer tail if it brings another info into contiguity
+ *  3) Prefer current primary
+ */
 map<int, PG::Info>::const_iterator PG::find_best_info(const map<int, Info> &infos) const
 {
   map<int, Info>::const_iterator best = infos.end();
diff --git a/src/osd/PG.h b/src/osd/PG.h
index 703217106009a..39bf1d91ad881 100644
--- a/src/osd/PG.h
+++ b/src/osd/PG.h
@@ -1388,6 +1388,15 @@ protected:
 
   epoch_t last_peering_reset;
 
+  /**
+   * BackfillInterval
+   *
+   * Represents the objects in a range [begin, end)
+   *
+   * Possible states:
+   * 1) begin == end == hobject_t() indicates the the interval is unpopulated
+   * 2) Else, objects contains all objects in [begin, end)
+   */
   struct BackfillInterval {
     // info about a backfill interval on a peer
     map<hobject_t,eversion_t> objects;
-- 
2.39.5