Better

src/Common/FileSegment.cpp

@@ -115,8 +115,7 @@ String FileSegment::getOrSetDownloader()
 {
     std::lock_guard segment_lock(mutex);
 
-    if (detached)
-        throw Exception(ErrorCodes::REMOTE_FS_OBJECT_CACHE_ERROR, "Cannot set downloader for a detached file segment");
+    assertNotDetached(segment_lock);
 
     if (downloader_id.empty())
     {
@@ -140,6 +139,8 @@ void FileSegment::resetDownloader()
 {
     std::lock_guard segment_lock(mutex);
 
+    assertNotDetached(segment_lock);
+
     if (downloader_id.empty())
         throw Exception(ErrorCodes::REMOTE_FS_OBJECT_CACHE_ERROR, "There is no downloader");
 
@@ -168,6 +169,7 @@ String FileSegment::getDownloader() const
 bool FileSegment::isDownloader() const
 {
     std::lock_guard segment_lock(mutex);
+
     return getCallerId() == downloader_id;
 }
 
@@ -232,8 +234,12 @@ void FileSegment::write(const char * from, size_t size, size_t offset_)
                         "Attempt to write {} bytes to offset: {}, but current download offset is {}",
                         size, offset_, download_offset);
 
+    std::unique_lock detach_lock(detach_mutex, std::defer_lock);
+
     {
         std::lock_guard segment_lock(mutex);
+        detach_lock.lock();
+
         assertNotDetached(segment_lock);
     }
 
@@ -278,6 +284,9 @@ FileSegment::State FileSegment::wait()
 {
     std::unique_lock segment_lock(mutex);
 
+    if (detached)
+        throwDetached();
+
     if (downloader_id.empty())
         return download_state;
 
@@ -302,8 +311,11 @@ bool FileSegment::reserve(size_t size)
     if (!size)
         throw Exception(ErrorCodes::REMOTE_FS_OBJECT_CACHE_ERROR, "Zero space reservation is not allowed");
 
+    std::unique_lock detach_lock(detach_mutex, std::defer_lock);
+
     {
         std::lock_guard segment_lock(mutex);
+        detach_lock.lock();
 
         assertNotDetached(segment_lock);
 
@@ -437,6 +449,9 @@ void FileSegment::complete(State state)
 void FileSegment::complete(std::lock_guard<std::mutex> & cache_lock)
 {
     std::lock_guard segment_lock(mutex);
+
+    assertNotDetached(segment_lock);
+
     completeUnlocked(cache_lock, segment_lock);
 }
 
@@ -585,16 +600,19 @@ void FileSegment::assertCorrectnessImpl(std::lock_guard<std::mutex> & /* segment
     assert(download_state != FileSegment::State::DOWNLOADED || std::filesystem::file_size(cache->getPathInLocalCache(key(), offset())) > 0);
 }
 
-void FileSegment::assertNotDetached(std::lock_guard<std::mutex> & /* segment_lock */) const
+void FileSegment::throwDetached()
 {
-    if (detached)
-    {
     throw Exception(
         ErrorCodes::REMOTE_FS_OBJECT_CACHE_ERROR,
         "Cache file segment is in detached state, operation not allowed. "
         "It can happen when cache was concurrently dropped with SYSTEM DROP FILESYSTEM CACHE FORCE. "
         "Please, retry");
-    }
+}
+
+void FileSegment::assertNotDetached(std::lock_guard<std::mutex> & /* segment_lock */) const
+{
+    if (detached)
+        throwDetached();
 }
 
 void FileSegment::assertDetachedStatus(std::lock_guard<std::mutex> & segment_lock) const
@@ -635,6 +653,8 @@ void FileSegment::detach(std::lock_guard<std::mutex> & /* cache_lock */, std::lo
     if (detached)
         return;
 
+    std::lock_guard detach_lock(detach_mutex);
+
     detached = true;
     download_state = State::PARTIALLY_DOWNLOADED_NO_CONTINUATION;
     downloader_id.clear();
@@ -658,14 +678,17 @@ FileSegmentsHolder::~FileSegmentsHolder()
         if (!cache)
             cache = file_segment->cache;
 
+        try
         {
             bool detached = false;
+
             {
                 std::lock_guard segment_lock(file_segment->mutex);
                 detached = file_segment->isDetached(segment_lock);
                 if (detached)
                     file_segment->assertDetachedStatus(segment_lock);
             }
+
             if (detached)
             {
                 /// This file segment is not owned by cache, so it will be destructed
@@ -674,10 +697,6 @@ FileSegmentsHolder::~FileSegmentsHolder()
                 continue;
             }
 
-        }
-
-        try
-        {
             /// File segment pointer must be reset right after calling complete() and
             /// under the same mutex, because complete() checks for segment pointers.
             std::lock_guard cache_lock(cache->mutex);
@@ -689,7 +708,6 @@ FileSegmentsHolder::~FileSegmentsHolder()
         catch (...)
         {
             tryLogCurrentException(__PRETTY_FUNCTION__);
-            assert(false);
         }
     }
 }

src/Common/FileSegment.h

@@ -158,6 +158,7 @@ private:
     void assertDetachedStatus(std::lock_guard<std::mutex> & segment_lock) const;
     bool hasFinalizedState() const;
     bool isDetached(std::lock_guard<std::mutex> & /* segment_lock */) const { return detached; }
+    [[noreturn]] static void throwDetached();
 
     void setDownloaded(std::lock_guard<std::mutex> & segment_lock);
     void setDownloadFailed(std::lock_guard<std::mutex> & segment_lock);
@@ -218,6 +219,7 @@ private:
     std::atomic<size_t> ref_count = 0; /// Used for getting snapshot state
 
     bool is_write_through_cache = false;
+    std::mutex detach_mutex;
 };
 
 struct FileSegmentsHolder : private boost::noncopyable

src/IO/WriteBufferFromS3.cpp

@@ -171,6 +171,9 @@ void WriteBufferFromS3::finalizeImpl()
 
     if (!multipart_upload_id.empty())
         completeMultipartUpload();
+
+    if (cacheEnabled())
+        cache_writer.finalize();
 }
 
 void WriteBufferFromS3::createMultipartUpload()