From: Greg Farnum <gfarnum@redhat.com>
Date: Mon, 23 May 2016 22:14:21 +0000 (-0700)
Subject: ObjectCacher: fix bh_read_finish offset logic
X-Git-Tag: ses5-milestone5~564^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=9ec6e7f608608088d51e449c9d375844631dcdde;p=ceph.git

ObjectCacher: fix bh_read_finish offset logic

If we have an incoming read split across multiple BufferHeads, we want to
line up the BufferHead's bl with the incoming OSDOp's bl at the right offset. We
were erroneously using this nonsense calculation (always equal to zero!) when
a much simpler comparison of the BufferHead's logical object offset to the
incoming OSDOp's logical offset will do the trick nicely.

Fixes: http://tracker.ceph.com/issues/16002

Signed-off-by: Greg Farnum <gfarnum@redhat.com>
---

diff --git a/src/osdc/ObjectCacher.cc b/src/osdc/ObjectCacher.cc
index 93b2412de53..90c8329a826 100644
--- a/src/osdc/ObjectCacher.cc
+++ b/src/osdc/ObjectCacher.cc
@@ -833,7 +833,6 @@ void ObjectCacher::bh_read_finish(int64_t poolid, sobject_t oid,
       if (bh->error < 0)
 	err = bh->error;
 
-      loff_t oldpos = opos;
       opos = bh->end();
 
       if (r == -ENOENT) {
@@ -853,7 +852,7 @@ void ObjectCacher::bh_read_finish(int64_t poolid, sobject_t oid,
 	mark_error(bh);
       } else {
 	bh->bl.substr_of(bl,
-			 oldpos-bh->start(),
+			 bh->start() - start,
 			 bh->length());
 	mark_clean(bh);
       }