From: Samuel Just <sam.just@inktank.com>
Date: Tue, 9 Sep 2014 19:35:52 +0000 (-0700)
Subject: Revert "ReplicatedPG:start_flush send a second delete"
X-Git-Tag: v0.86~110^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=937d2b0e487115f34265731d867eb6f47efdd746;p=ceph.git

Revert "ReplicatedPG:start_flush send a second delete"

This reverts commit a525bf3190a712fdceb018267a0aa08e90c44e62.

Conflicts:
	src/osd/ReplicatedPG.cc
---

diff --git a/src/osd/ReplicatedPG.cc b/src/osd/ReplicatedPG.cc
index 8ba1bdcaeef12..433f18705fec9 100644
--- a/src/osd/ReplicatedPG.cc
+++ b/src/osd/ReplicatedPG.cc
@@ -6398,19 +6398,7 @@ int ReplicatedPG::start_flush(
     cancel_flush(fop, false);
   }
 
-  /**
-   * In general, we need to send two deletes and a copyfrom.
-   * Consider snapc 10:[10, 9, 8, 4, 3, 2]:[10(10, 9), 4(4,3,2)]
-   * where 4 is marked as clean.  To flush 10, we have to:
-   * 1) delete 4:[4,3,2] -- ensure head is created at cloneid 4
-   * 2) delete (8-1):[4,3,2] -- ensure that the object does not exist at 8
-   * 3) copyfrom 8:[8,4,3,2] -- flush object excluding snap 8
-   *
-   * The second delete is required in case at some point in the past
-   * there had been a clone 7(7,6), which we had flushed.  Without
-   * the second delete, the object would appear in the base pool to
-   * have existed.
-   */
+  // construct a SnapContext appropriate for this clone/head
   SnapContext dsnapc;
   dsnapc.seq = 0;
   SnapContext snapc;
@@ -6442,15 +6430,17 @@ int ReplicatedPG::start_flush(
     vector<snapid_t>::iterator dnewest = p;
 
     // we may need to send a delete first
-    if (prev_snapc + 1 < *dnewest) {
-      while (p != snapset.snaps.end() && *p > prev_snapc)
-	++p;
-      dsnapc.snaps = vector<snapid_t>(p, snapset.snaps.end());
+    while (p != snapset.snaps.end() && *p > prev_snapc)
+      ++p;
+    dsnapc.snaps = vector<snapid_t>(p, snapset.snaps.end());
 
+    if (p == dnewest) {
+      // no snaps between the oldest in this clone and prev_snapc
+      snapc.seq = prev_snapc;
+    } else {
+      // snaps between oldest in this clone and prev_snapc, send delete
       dsnapc.seq = prev_snapc;
       snapc.seq = oi.snaps.back() - 1;
-    } else {
-      snapc.seq = prev_snapc;
     }
   }
 
@@ -6471,38 +6461,6 @@ int ReplicatedPG::start_flush(
        CEPH_OSD_FLAG_ENFORCE_SNAPC),
       NULL,
       NULL /* no callback, we'll rely on the ordering w.r.t the next op */);
-
-    // do we need to send the second delete?
-    SnapContext dsnapc2;
-    vector<snapid_t>::reverse_iterator rp = snapset.snaps.rbegin();
-
-    // advance rp to the smallest snap not contained by the last flushed clone
-    while (rp != snapset.snaps.rend() && *rp <= dsnapc.seq)
-      ++rp;
-
-    // set dnsnapc2.seq to be the snap prior to that snap (the object did not
-    // exist at *rq, so it must have been deleted prior to that).
-    dsnapc2.seq = (rp == snapset.snaps.rend()) ? snapset.seq : *rp;
-    if (dsnapc2.seq > 0)
-      dsnapc2.seq.val -= 1;
-
-    if (dsnapc2.seq != dsnapc.seq) {
-      dsnapc2.snaps = dsnapc.snaps;
-
-      ObjectOperation o2;
-      o2.remove();
-      osd->objecter->mutate(
-	soid.oid,
-	base_oloc,
-	o2,
-	dsnapc2,
-	oi.mtime,
-	(CEPH_OSD_FLAG_IGNORE_OVERLAY |
-	 CEPH_OSD_FLAG_ORDERSNAP |
-	 CEPH_OSD_FLAG_ENFORCE_SNAPC),
-	NULL,
-	NULL /* no callback, we'll rely on the ordering w.r.t the next op */);
-    }
   }
 
   FlushOpRef fop(new FlushOp);