Fix metaserver deadlock caused by bthread coroutine switching

Signed-off-by: Hanqing Wu <[email protected]>

Author: wu-hanqing

curvefs/src/metaserver/partition.cpp

@@ -29,6 +29,7 @@
 #include <memory>
 #include <string>
 #include <utility>
+#include <future>
 
 #include "curvefs/proto/metaserver.pb.h"
 #include "curvefs/src/metaserver/copyset/copyset_node_manager.h"
@@ -537,54 +538,68 @@ MetaStatusCode Partition::GetAllBlockGroup(
 }
 
 void Partition::StartS3Compact() {
-    S3CompactManager::GetInstance().Register(
-        S3Compact{inodeManager_, partitionInfo_});
+    // register s3 compaction task in a separate thread, since the caller may
+    // holds a pthread wrlock when calling this function, and create `S3Compact`
+    // will acquire a bthread rwlock, may cause thread switching, thus causing a
+    // deadlock.
+    // FIXME(wuhanqing): handle it in a more elegant way
+    auto handle = std::async(std::launch::async, [this]() {
+        S3CompactManager::GetInstance().Register(
+            S3Compact{inodeManager_, partitionInfo_});
+    });
+
+    handle.wait();
 }
 
 void Partition::CancelS3Compact() {
     S3CompactManager::GetInstance().Cancel(partitionInfo_.partitionid());
 }
 
 void Partition::StartVolumeDeallocate() {
-    FsInfo fsInfo;
-    bool ok =
-        FsInfoManager::GetInstance().GetFsInfo(partitionInfo_.fsid(), &fsInfo);
-    if (!ok) {
-        LOG(ERROR)
-            << "Partition start volume deallocate fail, get fsinfo fail. fsid="
-            << partitionInfo_.fsid();
-        return;
-    }
-
-    if (!fsInfo.detail().has_volume()) {
-        LOG(INFO) << "Partition not belong to volume, do not need start "
-                     "deallocate. partitionInfo="
-                  << partitionInfo_.DebugString();
-        return;
-    }
-
-    VolumeDeallocateCalOption calOpt;
-    calOpt.kvStorage = kvStorage_;
-    calOpt.inodeStorage = inodeStorage_;
-    calOpt.nameGen = nameGen_;
-    auto copysetNode =
-        copyset::CopysetNodeManager::GetInstance().GetSharedCopysetNode(
-            partitionInfo_.poolid(), partitionInfo_.copysetid());
-    if (copysetNode == nullptr) {
-        LOG(ERROR) << "Partition get copyset node failed. poolid="
-                   << partitionInfo_.poolid()
-                   << ", copysetid=" << partitionInfo_.copysetid();
-        return;
-    }
-
-    InodeVolumeSpaceDeallocate task(partitionInfo_.fsid(),
-                                    partitionInfo_.partitionid(), copysetNode);
-    task.Init(calOpt);
-
-    VolumeDeallocateManager::GetInstance().Register(std::move(task));
-
-    VLOG(3) << "Partition start volume deallocate success. partitionInfo="
-            << partitionInfo_.DebugString();
+    // FIXME(wuhanqing): same as `StartS3Compact`
+    auto handle = std::async(std::launch::async, [this]() {
+        FsInfo fsInfo;
+        bool ok = FsInfoManager::GetInstance().GetFsInfo(partitionInfo_.fsid(),
+                                                         &fsInfo);
+        if (!ok) {
+            LOG(ERROR) << "Partition start volume deallocate fail, get fsinfo "
+                          "fail. fsid="
+                       << partitionInfo_.fsid();
+            return;
+        }
+
+        if (!fsInfo.detail().has_volume()) {
+            LOG(INFO) << "Partition not belong to volume, do not need start "
+                         "deallocate. partitionInfo="
+                      << partitionInfo_.DebugString();
+            return;
+        }
+
+        VolumeDeallocateCalOption calOpt;
+        calOpt.kvStorage = kvStorage_;
+        calOpt.inodeStorage = inodeStorage_;
+        calOpt.nameGen = nameGen_;
+        auto copysetNode =
+            copyset::CopysetNodeManager::GetInstance().GetSharedCopysetNode(
+                partitionInfo_.poolid(), partitionInfo_.copysetid());
+        if (copysetNode == nullptr) {
+            LOG(ERROR) << "Partition get copyset node failed. poolid="
+                       << partitionInfo_.poolid()
+                       << ", copysetid=" << partitionInfo_.copysetid();
+            return;
+        }
+
+        InodeVolumeSpaceDeallocate task(
+            partitionInfo_.fsid(), partitionInfo_.partitionid(), copysetNode);
+        task.Init(calOpt);
+
+        VolumeDeallocateManager::GetInstance().Register(std::move(task));
+
+        VLOG(3) << "Partition start volume deallocate success. partitionInfo="
+                << partitionInfo_.DebugString();
+    });
+
+    handle.wait();
 }
 
 void Partition::CancelVolumeDeallocate() {

src/common/concurrent/rw_lock.h

@@ -23,13 +23,31 @@
 #ifndef SRC_COMMON_CONCURRENT_RW_LOCK_H_
 #define SRC_COMMON_CONCURRENT_RW_LOCK_H_
 
-#include <pthread.h>
 #include <assert.h>
-#include <glog/logging.h>
 #include <bthread/bthread.h>
+#include <glog/logging.h>
+#include <pthread.h>
+#include <sys/types.h>  // gettid
 
+#include "include/curve_compiler_specific.h"
 #include "src/common/uncopyable.h"
 
+// Due to the mixed use of bthread and pthread in some cases, acquiring another
+// bthread lock(mutex/rwlock) after acquiring a write lock on a pthread rwlock
+// may result in switching the bthread coroutine, and then the operation of
+// releasing the previous write lock in the other pthread will not take effect
+// (implying that the write lock is still held), thus causing a deadlock.
+
+// Check pthread rwlock tid between wrlock and unlock
+#if defined(ENABLE_CHECK_PTHREAD_WRLOCK_TID) && \
+    (ENABLE_CHECK_PTHREAD_WRLOCK_TID == 1)
+#define CURVE_CHECK_PTHREAD_WRLOCK_TID 1
+#elif !defined(ENABLE_CHECK_PTHREAD_WRLOCK_TID)
+#define CURVE_CHECK_PTHREAD_WRLOCK_TID 1
+#else
+#define CURVE_CHECK_PTHREAD_WRLOCK_TID 0
+#endif
+
 namespace curve {
 namespace common {
 
@@ -51,10 +69,21 @@ class PthreadRWLockBase : public RWLockBase {
     void WRLock() override {
         int ret = pthread_rwlock_wrlock(&rwlock_);
         CHECK(0 == ret) << "wlock failed: " << ret << ", " << strerror(ret);
+#if CURVE_CHECK_PTHREAD_WRLOCK_TID
+        tid_ = gettid();
+#endif
     }
 
     int TryWRLock() override {
-        return pthread_rwlock_trywrlock(&rwlock_);
+        int ret = pthread_rwlock_trywrlock(&rwlock_);
+        if (CURVE_UNLIKELY(ret != 0)) {
+            return ret;
+        }
+
+#if CURVE_CHECK_PTHREAD_WRLOCK_TID
+        tid_ = gettid();
+#endif
+        return 0;
     }
 
     void RDLock() override {
@@ -67,6 +96,19 @@ class PthreadRWLockBase : public RWLockBase {
     }
 
     void Unlock() override {
+#if CURVE_CHECK_PTHREAD_WRLOCK_TID
+        if (tid_ != 0) {
+            const pid_t current = gettid();
+            // If CHECK here is triggered, please look at the comments at the
+            // beginning of the file.
+            // In the meantime, the simplest solution might be to use
+            // `BthreadRWLock` locks everywhere.
+            CHECK(tid_ == current)
+                << ", tid has changed, previous tid: " << tid_
+                << ", current tid: " << current;
+            tid_ = 0;
+        }
+#endif
         pthread_rwlock_unlock(&rwlock_);
     }
 
@@ -76,8 +118,14 @@ class PthreadRWLockBase : public RWLockBase {
 
     pthread_rwlock_t rwlock_;
     pthread_rwlockattr_t rwlockAttr_;
+
+#if CURVE_CHECK_PTHREAD_WRLOCK_TID
+    pid_t tid_ = 0;
+#endif
 };
 
+#undef CURVE_CHECK_PTHREAD_WRLOCK_TID
+
 class RWLock : public PthreadRWLockBase {
  public:
     RWLock() {
@@ -122,7 +170,7 @@ class BthreadRWLock : public RWLockBase {
     }
 
     int TryWRLock() override {
-        // not support yet
+        LOG(WARNING) << "TryWRLock not support yet";
         return EINVAL;
     }
 
@@ -132,7 +180,7 @@ class BthreadRWLock : public RWLockBase {
     }
 
     int TryRDLock() override {
-        // not support yet
+        LOG(WARNING) << "TryRDLock not support yet";
         return EINVAL;
     }