From: Sage Weil <sage@redhat.com>
Date: Tue, 16 Dec 2014 01:04:32 +0000 (-0800)
Subject: osd: handle no-op write with snapshot case
X-Git-Tag: v0.92~102^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=02fae9fc54c10b5a932102bac43f32199d4cb612;p=ceph.git

osd: handle no-op write with snapshot case

If we have a transaction that does something to the object but it !exists
both before and after, we will continue through the write path.  If the
snapdir object already exists, and we try to create it again, we will
leak a snapdir obc and lock and later crash on an assert when the obc
is destroyed:

0> 2014-12-06 01:49:51.750163 7f08d6ade700 -1 osd/osd_types.h: In function 'ObjectContext::~ObjectContext()' thread 7f08d6ade700 time 2014-12-06 01:49:51.605411
osd/osd_types.h: 2944: FAILED assert(rwstate.empty())

Fix is to not recreated the snapdir if it already exists.

Fixes: #10262
Signed-off-by: Sage Weil <sage@redhat.com>
---

diff --git a/src/osd/ReplicatedPG.cc b/src/osd/ReplicatedPG.cc
index 5f3a7117a86..841b488dac2 100644
--- a/src/osd/ReplicatedPG.cc
+++ b/src/osd/ReplicatedPG.cc
@@ -5539,7 +5539,8 @@ void ReplicatedPG::finish_ctx(OpContext *ctx, int log_op_type, bool maintain_ssc
 	}
       }
     } else if (ctx->new_snapset.clones.size() &&
-	       !ctx->cache_evict) {
+	       !ctx->cache_evict &&
+	       (!ctx->snapset_obc || !ctx->snapset_obc->obs.exists)) {
       // save snapset on _snap
       hobject_t snapoid(soid.oid, soid.get_key(), CEPH_SNAPDIR, soid.hash,
 			info.pgid.pool(), soid.get_namespace());
@@ -5550,7 +5551,8 @@ void ReplicatedPG::finish_ctx(OpContext *ctx, int log_op_type, bool maintain_ssc
 	                                eversion_t(),
 					0, osd_reqid_t(), ctx->mtime));
 
-      ctx->snapset_obc = get_object_context(snapoid, true);
+      if (!ctx->snapset_obc)
+	ctx->snapset_obc = get_object_context(snapoid, true);
       bool got = ctx->snapset_obc->get_write_greedy(ctx->op);
       assert(got);
       dout(20) << " got greedy write on snapset_obc " << *ctx->snapset_obc << dendl;
diff --git a/src/test/librados/snapshots.cc b/src/test/librados/snapshots.cc
index e9c566a711d..2431495eee9 100644
--- a/src/test/librados/snapshots.cc
+++ b/src/test/librados/snapshots.cc
@@ -145,6 +145,24 @@ TEST_F(LibRadosSnapshotsPP, SnapGetNamePP) {
   EXPECT_EQ(0, ioctx.snap_remove("snapfoo"));
 }
 
+TEST_F(LibRadosSnapshotsPP, SnapCreateRemovePP) {
+  // reproduces http://tracker.ceph.com/issues/10262
+  bufferlist bl;
+  bl.append("foo");
+  ASSERT_EQ(0, ioctx.write("foo", bl, bl.length(), 0));
+  ASSERT_EQ(0, ioctx.snap_create("snapfoo"));
+  ASSERT_EQ(0, ioctx.remove("foo"));
+  ASSERT_EQ(0, ioctx.snap_create("snapbar"));
+
+  librados::ObjectWriteOperation *op = new librados::ObjectWriteOperation();
+  op->create(false);
+  op->remove();
+  ASSERT_EQ(0, ioctx.operate("foo", op));
+
+  EXPECT_EQ(0, ioctx.snap_remove("snapfoo"));
+  EXPECT_EQ(0, ioctx.snap_remove("snapbar"));
+}
+
 TEST_F(LibRadosSnapshotsSelfManaged, Snap) {
   std::vector<uint64_t> my_snaps;
   my_snaps.push_back(-2);