osdc: Make last missing bh to wake up the reader.

Avoid wakeup early and wait again.

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>

diff --git a/src/osdc/ObjectCacher.cc b/src/osdc/ObjectCacher.cc
index eef961ff560a0878f665d4034c5e67c093427576..0935fae16d22610793481b7d32f00b2abadfa19e 100644 (file)
--- a/src/osdc/ObjectCacher.cc
+++ b/src/osdc/ObjectCacher.cc
@@ -1142,6 +1142,7 @@ int ObjectCacher::_readx(OSDRead *rd, ObjectSet *oset, Context *onfinish,
 
     if (!missing.empty() || !rx.empty()) {
       // read missing
+      map<loff_t, BufferHead*>::iterator last = missing.end();
       for (map<loff_t, BufferHead*>::iterator bh_it = missing.begin();
            bh_it != missing.end();
            ++bh_it) {
@@ -1162,16 +1163,21 @@ int ObjectCacher::_readx(OSDRead *rd, ObjectSet *oset, Context *onfinish,
          delete bh_it->second;
        } else {
          bh_read(bh_it->second, rd->fadvise_flags);
-         if (success && onfinish) {
-           ldout(cct, 10) << "readx missed, waiting on " << *bh_it->second
-                          << " off " << bh_it->first << dendl;
-           bh_it->second->waitfor_read[bh_it->first].push_back( new C_RetryRead(this, rd, oset, onfinish) );
-         }
+         if ((success && onfinish) || last != missing.end())
+           last = bh_it;
        }
         bytes_not_in_cache += bh_it->second->length();
        success = false;
       }
 
+      //add wait in last bh avoid wakeup early. Because read is order
+      if (last != missing.end()) {
+       ldout(cct, 10) << "readx missed, waiting on " << *last->second
+         << " off " << last->first << dendl;
+       last->second->waitfor_read[last->first].push_back( new C_RetryRead(this, rd, oset, onfinish) );
+
+      }
+
       // bump rx
       for (map<loff_t, BufferHead*>::iterator bh_it = rx.begin();
            bh_it != rx.end();