osdc: In _readx() only no error can tidy read result.

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>
(cherry picked from commit 540346d4a901d8041c9fd74641c98cdfd2e1ab32)

diff --git a/src/osdc/ObjectCacher.cc b/src/osdc/ObjectCacher.cc
index e7fa908e13d4b1b61959ea963f608bf8ea0410fc..3f52f55bdffcf989210564ab0a2f6c961d0f873a 100644 (file)
--- a/src/osdc/ObjectCacher.cc
+++ b/src/osdc/ObjectCacher.cc
@@ -1210,56 +1210,58 @@ int ObjectCacher::_readx(OSDRead *rd, ObjectSet *oset, Context *onfinish,
        }
       }
 
-      // create reverse map of buffer offset -> object for the eventual result.
-      // this is over a single ObjectExtent, so we know that
-      //  - the bh's are contiguous
-      //  - the buffer frags need not be (and almost certainly aren't)
-      loff_t opos = ex_it->offset;
-      map<loff_t, BufferHead*>::iterator bh_it = hits.begin();
-      assert(bh_it->second->start() <= opos);
-      uint64_t bhoff = opos - bh_it->second->start();
-      vector<pair<uint64_t,uint64_t> >::iterator f_it = ex_it->buffer_extents.begin();
-      uint64_t foff = 0;
-      while (1) {
-        BufferHead *bh = bh_it->second;
-        assert(opos == (loff_t)(bh->start() + bhoff));
-
-        uint64_t len = MIN(f_it->second - foff, bh->length() - bhoff);
-        ldout(cct, 10) << "readx rmap opos " << opos
-                      << ": " << *bh << " +" << bhoff
-                      << " frag " << f_it->first << "~" << f_it->second << " +" << foff << "~" << len
-                      << dendl;
+      if (!error) {
+       // create reverse map of buffer offset -> object for the eventual result.
+       // this is over a single ObjectExtent, so we know that
+       //  - the bh's are contiguous
+       //  - the buffer frags need not be (and almost certainly aren't)
+       loff_t opos = ex_it->offset;
+       map<loff_t, BufferHead*>::iterator bh_it = hits.begin();
+       assert(bh_it->second->start() <= opos);
+       uint64_t bhoff = opos - bh_it->second->start();
+       vector<pair<uint64_t,uint64_t> >::iterator f_it = ex_it->buffer_extents.begin();
+       uint64_t foff = 0;
+       while (1) {
+         BufferHead *bh = bh_it->second;
+         assert(opos == (loff_t)(bh->start() + bhoff));
+
+         uint64_t len = MIN(f_it->second - foff, bh->length() - bhoff);
+         ldout(cct, 10) << "readx rmap opos " << opos
+           << ": " << *bh << " +" << bhoff
+           << " frag " << f_it->first << "~" << f_it->second << " +" << foff << "~" << len
+           << dendl;
+
+         bufferlist bit;  // put substr here first, since substr_of clobbers, and
+         // we may get multiple bh's at this stripe_map position
+         if (bh->is_zero()) {
+           bufferptr bp(len);
+           bp.zero();
+           stripe_map[f_it->first].push_back(bp);
+         } else {
+           bit.substr_of(bh->bl,
+               opos - bh->start(),
+               len);
+           stripe_map[f_it->first].claim_append(bit);
+         }
 
-       bufferlist bit;  // put substr here first, since substr_of clobbers, and
-                        // we may get multiple bh's at this stripe_map position
-       if (bh->is_zero()) {
-         bufferptr bp(len);
-         bp.zero();
-         stripe_map[f_it->first].push_back(bp);
-       } else {
-         bit.substr_of(bh->bl,
-                       opos - bh->start(),
-                       len);
-         stripe_map[f_it->first].claim_append(bit);
+         opos += len;
+         bhoff += len;
+         foff += len;
+         if (opos == bh->end()) {
+           ++bh_it;
+           bhoff = 0;
+         }
+         if (foff == f_it->second) {
+           ++f_it;
+           foff = 0;
+         }
+         if (bh_it == hits.end()) break;
+         if (f_it == ex_it->buffer_extents.end())
+           break;
        }
-
-        opos += len;
-        bhoff += len;
-        foff += len;
-        if (opos == bh->end()) {
-          ++bh_it;
-          bhoff = 0;
-        }
-        if (foff == f_it->second) {
-          ++f_it;
-          foff = 0;
-        }
-        if (bh_it == hits.end()) break;
-        if (f_it == ex_it->buffer_extents.end())
-         break;
+       assert(f_it == ex_it->buffer_extents.end());
+       assert(opos == (loff_t)ex_it->offset + (loff_t)ex_it->length);
       }
-      assert(f_it == ex_it->buffer_extents.end());
-      assert(opos == (loff_t)ex_it->offset + (loff_t)ex_it->length);
 
       if (dontneed && o->include_all_cached_data(ex_it->offset, ex_it->length))
          bottouch_ob(o);
@@ -1303,7 +1305,7 @@ int ObjectCacher::_readx(OSDRead *rd, ObjectSet *oset, Context *onfinish,
       assert(rd->bl->length() == pos);
     }
     ldout(cct, 10) << "readx  result is " << rd->bl->length() << dendl;
-  } else {
+  } else if (!error) {
     ldout(cct, 10) << "readx  no bufferlist ptr (readahead?), done." << dendl;
     map<uint64_t,bufferlist>::reverse_iterator i = stripe_map.rbegin();
     pos = i->first + i->second.length();