Additional Fixes and comments

Summary:

Test Plan:

Reviewers:

Subscribers:

Tasks:

Tags:

file/file_prefetch_buffer.cc

@@ -685,7 +685,6 @@ Status FilePrefetchBuffer::PrefetchAsyncInternal(const IOOptions& opts,
     UpdateStats(/*found_in_buffer=*/false,
                 /*length_found=*/original_length - length);
   } else {
-    end_offset1 = buf->offset_ + buf->buffer_.CurrentSize();
     UpdateStats(/*found_in_buffer=*/true, original_length);
   }
 

file/file_prefetch_buffer.h

@@ -162,6 +162,14 @@ class FilePrefetchBuffer {
         Status s = fs_->AbortIO(handles);
         assert(s.ok());
       }
+
+      for (auto& buf : bufs_) {
+        if (buf->io_handle_ != nullptr) {
+          DestroyAndClearIOHandle(buf);
+          buf->async_read_in_progress_ = false;
+          buf->ClearBuffer();
+        }
+      }
     }
 
     // Prefetch buffer bytes discarded.
@@ -195,6 +203,11 @@ class FilePrefetchBuffer {
       delete buf;
       buf = nullptr;
     }
+
+    for (auto& buf : overlap_bufs_) {
+      delete buf;
+      buf = nullptr;
+    }
   }
 
   bool Enabled() const { return enable_; }
@@ -274,6 +287,10 @@ class FilePrefetchBuffer {
     //   - block is sequential with the previous read and,
     //   - num_file_reads_ + 1 (including this read) >
     //   num_file_reads_for_auto_readahead_
+    if (bufs_.empty()) {
+      return;
+    }
+
     size_t curr_size = bufs_.front()->async_read_in_progress_
                            ? bufs_.front()->async_req_len_
                            : bufs_.front()->buffer_.CurrentSize();