From 6214d7c945b5d32222d83259740290bae75a8f33 Mon Sep 17 00:00:00 2001
From: Kefu Chai <kchai@redhat.com>
Date: Mon, 21 Dec 2020 00:12:41 +0800
Subject: [PATCH] crimson/osd: extract read_metadata_for_push_op() out

for better readability

Signed-off-by: Kefu Chai <kchai@redhat.com>
---
 .../osd/replicated_recovery_backend.cc        | 82 +++++++++++--------
 src/crimson/osd/replicated_recovery_backend.h | 10 +++
 2 files changed, 60 insertions(+), 32 deletions(-)

diff --git a/src/crimson/osd/replicated_recovery_backend.cc b/src/crimson/osd/replicated_recovery_backend.cc
index 644c51eb9e120..c68661fffed28 100644
--- a/src/crimson/osd/replicated_recovery_backend.cc
+++ b/src/crimson/osd/replicated_recovery_backend.cc
@@ -352,44 +352,20 @@ seastar::future<PushOp> ReplicatedRecoveryBackend::build_push_op(
   logger().debug("{} {} @{}",
 		 __func__, recovery_info.soid, recovery_info.version);
   return seastar::do_with(ObjectRecoveryProgress(progress),
-			  object_info_t(),
 			  uint64_t(crimson::common::local_conf()
 			    ->osd_recovery_max_chunk),
 			  eversion_t(),
 			  PushOp(),
     [this, &recovery_info, &progress, stat]
-    (auto& new_progress, auto& oi, auto& available, auto& v, auto& pop) {
-    return [this, &recovery_info, &progress, &new_progress, &oi, &v, pop=&pop] {
-      v = recovery_info.version;
-      if (progress.first) {
-        return seastar::when_all_succeed(
-          backend->omap_get_header(coll, ghobject_t(recovery_info.soid)).safe_then(
-            [&pop](auto bl) {
-            pop->omap_header.claim_append(bl);
-          }, crimson::os::FuturizedStore::read_errorator::all_same_way(
-            [] (const std::error_code& e) {
-            return seastar::make_exception_future<>(e);
-          })),
-          store->get_attrs(coll, ghobject_t(recovery_info.soid)).safe_then(
-            [&oi, pop, &v](auto attrs) mutable {
-            for (auto& [key, val] : attrs) {
-              pop->attrset[std::move(key)].push_back(std::move(val));
-            }
-            logger().debug("build_push_op: {}", pop->attrset[OI_ATTR]);
-            oi.decode(pop->attrset[OI_ATTR]);
-            if (v == eversion_t()) {
-              v = oi.version;
-            }
-          }, crimson::os::FuturizedStore::read_errorator::all_same_way(
-            [] (const std::error_code& e) {
-            return seastar::make_exception_future<>(e);
-          }))
-        ).then_unpack([&new_progress] {
-          new_progress.first = false;
-        });
+    (auto& new_progress, auto& available, auto& v, auto& pop) {
+    v = recovery_info.version;
+    return read_metadata_for_push_op(recovery_info.soid,
+                                     progress, new_progress,
+                                     v, &pop).then([&](eversion_t local_ver) mutable {
+      // If requestor didn't know the version, use ours
+      if (v == eversion_t()) {
+        v = local_ver;
       }
-      return seastar::make_ready_future<>();
-    }().then([this, &recovery_info, &progress, &new_progress, &available, &pop]() mutable {
       return read_omap_for_push_op(recovery_info.soid,
                                    progress,
                                    new_progress,
@@ -429,6 +405,48 @@ seastar::future<PushOp> ReplicatedRecoveryBackend::build_push_op(
   });
 }
 
+seastar::future<eversion_t>
+ReplicatedRecoveryBackend::read_metadata_for_push_op(
+    const hobject_t& oid,
+    const ObjectRecoveryProgress& progress,
+    ObjectRecoveryProgress& new_progress,
+    eversion_t ver,
+    PushOp* push_op)
+{
+  if (!progress.first) {
+    return seastar::make_ready_future<eversion_t>(ver);
+  }
+  return seastar::when_all_succeed(
+    backend->omap_get_header(coll, ghobject_t(oid)).handle_error(
+      crimson::os::FuturizedStore::read_errorator::all_same_way(
+        [] (const std::error_code& e) {
+        return seastar::make_ready_future<bufferlist>();
+      })),
+    store->get_attrs(coll, ghobject_t(oid)).handle_error(
+      crimson::os::FuturizedStore::get_attrs_ertr::all_same_way(
+        [] (const std::error_code& e) {
+        return seastar::make_ready_future<crimson::os::FuturizedStore::attrs_t>();
+      }))
+  ).then_unpack([&new_progress, push_op](auto bl, auto attrs) {
+    if (bl.length() == 0) {
+      logger().error("read_metadata_for_push_op: fail to read omap header");
+      return eversion_t{};
+    } else if (attrs.empty()) {
+      logger().error("read_metadata_for_push_op: fail to read attrs");
+      return eversion_t{};
+    }
+    push_op->omap_header.claim_append(std::move(bl));
+    for (auto&& [key, val] : std::move(attrs)) {
+      push_op->attrset[key].push_back(val);
+    }
+    logger().debug("read_metadata_for_push_op: {}", push_op->attrset[OI_ATTR]);
+    object_info_t oi;
+    oi.decode(push_op->attrset[OI_ATTR]);
+    new_progress.first = false;
+    return oi.version;
+  });
+}
+
 seastar::future<uint64_t>
 ReplicatedRecoveryBackend::read_object_for_push_op(
     const hobject_t& oid,
diff --git a/src/crimson/osd/replicated_recovery_backend.h b/src/crimson/osd/replicated_recovery_backend.h
index 6a4ed9802ab1d..d99538a759b21 100644
--- a/src/crimson/osd/replicated_recovery_backend.h
+++ b/src/crimson/osd/replicated_recovery_backend.h
@@ -119,6 +119,16 @@ private:
     const hobject_t& soid,
     eversion_t need);
 
+  /// read the data attached to given object. the size of them is supposed to
+  /// be relatively small.
+  ///
+  /// @return @c oi.version
+  seastar::future<eversion_t> read_metadata_for_push_op(
+    const hobject_t& oid,
+    const ObjectRecoveryProgress& progress,
+    ObjectRecoveryProgress& new_progress,
+    eversion_t ver,
+    PushOp* push_op);
   /// read the remaining extents of object to be recovered and fill push_op
   /// with them
   ///
-- 
2.39.5