From: Samuel Just <sjust@redhat.com>
Date: Fri, 19 Jun 2020 22:22:19 +0000 (-0700)
Subject: PrimaryLogPG: simplify dec_all_refcount_manifest
X-Git-Tag: v16.1.0~1738^2~4
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=47f42300f0d3270c59eb190e9a331e9d76eec707;p=ceph.git

PrimaryLogPG: simplify dec_all_refcount_manifest

We should only need one path with calc_refs_to_drop_on_removal to
handle all manifest cases.

Signed-off-by: Samuel Just <sjust@redhat.com>
---

diff --git a/src/osd/PrimaryLogPG.cc b/src/osd/PrimaryLogPG.cc
index d90bf01364f..51f37adb47a 100644
--- a/src/osd/PrimaryLogPG.cc
+++ b/src/osd/PrimaryLogPG.cc
@@ -3462,6 +3462,7 @@ void PrimaryLogPG::dec_refcount(ObjectContextRef obc, const object_ref_delta_t&
 {
   for (auto p = refs.begin(); p != refs.end(); ++p) {
     int dec_ref_count = p->second;
+    ceph_assert(dec_ref_count < 0);
     while (dec_ref_count < 0) {
       dout(10) << __func__ << ": decrement reference on offset oid: " << p->first << dendl;
       refcount_manifest(obc->obs.oi.soid, p->first, 
@@ -3472,80 +3473,60 @@ void PrimaryLogPG::dec_refcount(ObjectContextRef obc, const object_ref_delta_t&
 }
 
 
-void PrimaryLogPG::dec_all_refcount_manifest(object_info_t& oi, OpContext* ctx)
+void PrimaryLogPG::dec_all_refcount_manifest(const object_info_t& oi, OpContext* ctx)
 {
-  SnapSetContext* ssc = ctx->obc->ssc;
   ceph_assert(oi.has_manifest());
-  // has snapshot
-  if (ssc && ssc->snapset.clones.size() > 0) {
-    ceph_assert(ssc);
-    dout(15) << __func__ <<  " has snapset " << dendl;
-    object_ref_delta_t refs;
-    ceph_assert(oi.manifest.is_chunked());
-    ceph_assert(!oi.manifest.is_redirect());
-
-    SnapSet& snapset = ssc->snapset;
+  ceph_assert(ctx->obc->ssc);
 
-    // check adjacent clones
-    auto s = std::find(snapset.clones.begin(), snapset.clones.end(), oi.soid.snap);
-    int index = std::distance(snapset.clones.begin(), s);
-    snapid_t l = *snapset.clones.begin(), g = CEPH_NOSNAP;
-    object_manifest_t* manifest_g = nullptr, * manifest_l = nullptr;
-    hobject_t t_oid = oi.soid;
+  if (oi.manifest.is_chunked()) {
+    const SnapSet& snapset = ctx->obc->ssc->snapset;
 
-    auto get_context = [this](const hobject_t & oid) 
+    auto get_context = [this, &oi, &snapset](auto iter)
       -> ObjectContextRef {
-      ObjectContextRef obc = get_object_context(oid, false, NULL);
+      hobject_t cid = oi.soid;
+      cid.snap = (iter == snapset.clones.end()) ? snapid_t(CEPH_NOSNAP) : *iter;
+      ObjectContextRef obc = get_object_context(cid, false, NULL);
       ceph_assert(obc);
       ceph_assert(obc->obs.oi.has_manifest());
       ceph_assert(obc->obs.oi.manifest.is_chunked());
       return obc;
     };
+    ObjectContextRef obc_l, obc_g;
 
-    if (index) {
-      l = snapset.clones[index - 1];
-      t_oid.snap = l;
-      manifest_l = &get_context(t_oid)->obs.oi.manifest;
-    } 
+    // check adjacent clones
+    auto s = std::find(snapset.clones.begin(), snapset.clones.end(), oi.soid.snap);
 
-    if (snapset.clones.size() != 0 && s != snapset.clones.end() 
-	&& *s != snapset.clones.back()) {
-      g = snapset.clones[index + 1];
-      t_oid.snap = g;
-      manifest_g = &get_context(t_oid)->obs.oi.manifest;
-    } else if (*s == snapset.clones.back()) {
-      manifest_g = &get_context(oi.soid.get_head())->obs.oi.manifest;
+    // We *must* find the clone iff it's not head,
+    // let s == snapset.clones.end() mean head
+    ceph_assert((s == snapset.clones.end()) == oi.soid.is_head()); 
+
+    if (s != snapset.clones.begin()) {
+      obc_l = get_context(s - 1);
     }
-    
-    
-    oi.manifest.calc_refs_to_drop_on_removal(manifest_g, manifest_l, refs);
+
+    if (s != snapset.clones.end()) {
+      obc_g = get_context(s + 1);
+    }
+
+    object_ref_delta_t refs;
+    oi.manifest.calc_refs_to_drop_on_removal(
+      obc_l ? &(obc_l->obs.oi.manifest) : nullptr,
+      obc_g ? &(obc_g->obs.oi.manifest) : nullptr,
+      refs);
 
     if (!refs.is_empty()) {
       ctx->register_on_commit(
 	[ctx, this, refs](){
 	  dec_refcount(ctx->obc, refs);
-      });
+	});
     }
-    return;
-  }
-
-  // no snapshot
-  if ((oi.flags & object_info_t::FLAG_REDIRECT_HAS_REFERENCE) && oi.manifest.is_redirect()) {
+  } else if (oi.manifest.is_redirect()) {
+    ceph_assert(oi.flags & object_info_t::FLAG_REDIRECT_HAS_REFERENCE);
     ctx->register_on_commit(
       [oi, this](){
-      refcount_manifest(oi.soid, oi.manifest.redirect_target, 
-			refcount_t::DECREMENT_REF, NULL);
-    });
-  } else if (oi.manifest.is_chunked()) {
-    ctx->register_on_commit(
-      [oi, this](){
-      for (auto p : oi.manifest.chunk_map) {
-	if (p.second.has_reference()) {
-	  refcount_manifest(oi.soid, p.second.oid, 
-			    refcount_t::DECREMENT_REF, NULL);
-	}
-      }
-    });
+	refcount_manifest(oi.soid, oi.manifest.redirect_target, 
+			  refcount_t::DECREMENT_REF, NULL);
+      });
   } else {
     ceph_abort_msg("unrecognized manifest type");
   }
diff --git a/src/osd/PrimaryLogPG.h b/src/osd/PrimaryLogPG.h
index 4864f217e1a..78663bddafb 100644
--- a/src/osd/PrimaryLogPG.h
+++ b/src/osd/PrimaryLogPG.h
@@ -1501,7 +1501,7 @@ protected:
   void cancel_manifest_ops(bool requeue, vector<ceph_tid_t> *tids);
   void refcount_manifest(hobject_t src_soid, hobject_t tgt_soid, refcount_t type,
 			 RefCountCallback* cb);
-  void dec_all_refcount_manifest(object_info_t& oi, OpContext* ctx);
+  void dec_all_refcount_manifest(const object_info_t& oi, OpContext* ctx);
   void dec_refcount(ObjectContextRef obc, const object_ref_delta_t& refs);
 
   friend struct C_ProxyChunkRead;