From 19cce9a57310677693d1b0cbc5255b22c520f442 Mon Sep 17 00:00:00 2001
From: Matan Breizman <mbreizma@redhat.com>
Date: Tue, 28 May 2024 13:23:10 +0000
Subject: [PATCH] crimson/osd/object_context: await in-progress loading
 (per-obc)

```
  // obc loading is a concurrent phase. In case this obc is being loaded,
  // make other useres of this obc to await for the loading to complete.
```

Since we now await for loading to finish (in-case in progress), we can
also assert is_loaded().

Fixes: https://tracker.ceph.com/issues/65451

Co-authored-by: Xuehan Xu <xuxuehan@qianxin.com>
Signed-off-by: Matan Breizman <mbreizma@redhat.com>
(cherry picked from commit e456bd7cdd1ad1cd68026cebedd5b1d9d01001f7)
---
 src/crimson/common/interruptible_future.h | 11 ++++++++
 src/crimson/osd/object_context.h          |  4 +++
 src/crimson/osd/object_context_loader.cc  | 31 +++++++++++++----------
 src/crimson/osd/object_context_loader.h   |  3 +++
 4 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/src/crimson/common/interruptible_future.h b/src/crimson/common/interruptible_future.h
index 27467f2396265..0e2a238edd08f 100644
--- a/src/crimson/common/interruptible_future.h
+++ b/src/crimson/common/interruptible_future.h
@@ -1218,6 +1218,17 @@ public:
 	    };
   }
 
+  template <typename Lock, typename Func>
+  [[gnu::always_inline]]
+  static auto with_lock(Lock& lock, Func&& func) {
+    return seastar::with_lock(
+      lock,
+      [func=std::move(func),
+       interrupt_condition=interrupt_cond<InterruptCond>.interrupt_cond]() mutable {
+      return call_with_interruption(interrupt_condition, func);
+    });
+  }
+
   template <typename Iterator,
 	    InvokeReturnsInterruptibleFuture<typename Iterator::reference> AsyncAction>
   [[gnu::always_inline]]
diff --git a/src/crimson/osd/object_context.h b/src/crimson/osd/object_context.h
index d651dc912fd52..9aa5d60a80039 100644
--- a/src/crimson/osd/object_context.h
+++ b/src/crimson/osd/object_context.h
@@ -70,6 +70,10 @@ public:
   using watch_key_t = std::pair<uint64_t, entity_name_t>;
   std::map<watch_key_t, seastar::shared_ptr<crimson::osd::Watch>> watchers;
 
+  // obc loading is a concurrent phase. In case this obc is being loaded,
+  // make other users of this obc to await for the loading to complete.
+  seastar::shared_mutex loading_mutex;
+
   ObjectContext(hobject_t hoid) : obs(std::move(hoid)) {}
 
   const hobject_t &get_oid() const {
diff --git a/src/crimson/osd/object_context_loader.cc b/src/crimson/osd/object_context_loader.cc
index d8035b440ea1f..9af927806d568 100644
--- a/src/crimson/osd/object_context_loader.cc
+++ b/src/crimson/osd/object_context_loader.cc
@@ -149,20 +149,23 @@ using crimson::common::local_conf;
              dpp, obc->get_oid(),
              obc->fully_loaded,
              obc->invalidated_by_interval_change);
-    auto loaded =
-      load_obc_iertr::make_ready_future<ObjectContextRef>(obc);
-    if (existed && obc->is_loaded()) {
-      ceph_assert(obc->is_valid());
-      DEBUGDPP("cache hit on {}", dpp, obc->get_oid());
-    } else {
-      DEBUGDPP("cache miss on {}", dpp, obc->get_oid());
-      loaded =
-        obc->template with_promoted_lock<State, IOInterruptCondition>(
-        [obc, this] {
-        return load_obc(obc);
-      });
-    }
-    return loaded;
+    return interruptor::with_lock(obc->loading_mutex,
+    [this, obc, existed, FNAME] {
+      auto loaded =
+        load_obc_iertr::make_ready_future<ObjectContextRef>(obc);
+      if (existed) {
+        ceph_assert(obc->is_valid() && obc->is_loaded());
+        DEBUGDPP("cache hit on {}", dpp, obc->get_oid());
+      } else {
+        DEBUGDPP("cache miss on {}", dpp, obc->get_oid());
+        loaded =
+          obc->template with_promoted_lock<State, IOInterruptCondition>(
+          [obc, this] {
+          return load_obc(obc);
+        });
+      }
+      return loaded;
+    });
   }
 
   ObjectContextLoader::load_obc_iertr::future<>
diff --git a/src/crimson/osd/object_context_loader.h b/src/crimson/osd/object_context_loader.h
index 77805e11bc167..b51e10caf77e8 100644
--- a/src/crimson/osd/object_context_loader.h
+++ b/src/crimson/osd/object_context_loader.h
@@ -29,6 +29,9 @@ public:
       ::crimson::osd::IOInterruptCondition,
       load_obc_ertr>;
 
+  using interruptor = ::crimson::interruptible::interruptor<
+    ::crimson::osd::IOInterruptCondition>;
+
   using with_obc_func_t =
     std::function<load_obc_iertr::future<> (ObjectContextRef, ObjectContextRef)>;
 
-- 
2.39.5