osd: add comment to explain why EC pool is disallowed

Signed-off-by: Myoungwon Oh <myoungwon.oh@samsumg.com>

diff --git a/src/osd/PrimaryLogPG.cc b/src/osd/PrimaryLogPG.cc
index 47db8c5603d0e1a29b4087adc2e456fe5d42a58f..af6a5a8dfe76cced11bdd4aa12bc7dab8c3d4243 100644 (file)
--- a/src/osd/PrimaryLogPG.cc
+++ b/src/osd/PrimaryLogPG.cc
@@ -10125,7 +10125,12 @@ int PrimaryLogPG::do_cdc(const object_info_t& oi, bufferlist& bl, vector<pair<ui
   }
   while (cur_off < oi.size && cur_off < max_window_size) {
     bufferlist chunk_data;
-    // TODO: Do we need to support EC?
+    /**
+     * We disable EC pool as a base tier of distributed dedup.
+     * The reason why we disallow erasure code pool here is that the EC pool does not support objects_read_sync(). 
+     * Therefore, we should change the current implementation totally to make EC pool compatible. 
+     * As s result, we leave this as a future work.
+     */
     int r = pgbackend->objects_read_sync(
        oi.soid, cur_off, max_window_size, 0, &chunk_data);
     if (r < 0) {