diff --git a/Network/Wai/Handler/Warp/Buffer.hs b/Network/Wai/Handler/Warp/Buffer.hs
--- a/Network/Wai/Handler/Warp/Buffer.hs
+++ b/Network/Wai/Handler/Warp/Buffer.hs
@@ -12,7 +12,6 @@
   , bufferIO
   ) where
 
-import Control.Monad (when)
 import qualified Data.ByteString as BS
 import Data.ByteString.Internal (ByteString(..), memcpy)
 import Data.ByteString.Unsafe (unsafeTake, unsafeDrop)
@@ -69,7 +68,7 @@
 {-# INLINE getBuffer #-}
 
 putBuffer :: BufferPool -> ByteString -> IO ()
-putBuffer pool buffer = when (usefulBuffer buffer) $ writeIORef pool buffer
+putBuffer pool buffer = writeIORef pool buffer
 {-# INLINE putBuffer #-}
 
 withForeignBuffer :: ByteString -> ((Buffer, BufSize) -> IO Int) -> IO Int
diff --git a/Network/Wai/Handler/Warp/HTTP2/Receiver.hs b/Network/Wai/Handler/Warp/HTTP2/Receiver.hs
--- a/Network/Wai/Handler/Warp/HTTP2/Receiver.hs
+++ b/Network/Wai/Handler/Warp/HTTP2/Receiver.hs
@@ -142,7 +142,7 @@
                  Just strm0 -> do
                      when (ftyp == FrameHeaders) $ do
                          st <- readIORef $ streamState strm0
-                         when (isHalfClosed st) $ E.throwIO $ ConnectionError ProtocolError "header must not be sent to half closed"
+                         when (isHalfClosed st) $ E.throwIO $ ConnectionError StreamClosed "header must not be sent to half closed"
                      return strm0
                  Nothing    -> do
                      when (ftyp `notElem` [FrameHeaders,FramePriority]) $
@@ -154,8 +154,17 @@
                            else
                              writeIORef currentStreamId streamId
                          cnt <- readIORef concurrency
-                         when (cnt >= recommendedConcurrency) $
-                             E.throwIO $ ConnectionError RefusedStream "over max concurrency"
+                         when (cnt >= recommendedConcurrency) $ do
+                             -- Record that the stream is closed, rather than
+                             -- idle, so that receiving frames on it is only a
+                             -- stream error.
+                             consume payloadLength
+                             strm <- newStream streamId 0
+                             writeIORef (streamState strm) $ Closed $
+                                 ResetByMe $ E.toException $
+                                     StreamError RefusedStream streamId
+                             insert streamTable streamId strm
+                             E.throwIO $ StreamError RefusedStream streamId
                      ws <- initialWindowSize <$> readIORef http2settings
                      newstrm <- newStream streamId (fromIntegral ws)
                      when (ftyp == FrameHeaders) $ opened ctx newstrm
@@ -291,8 +300,6 @@
       else
         return $ Open $ Continued rfrags' siz' n' endOfStream pri
 
-stream FrameContinuation _ _ _ _ _ = E.throwIO $ ConnectionError ProtocolError "continue frame cannot come here"
-
 stream FrameWindowUpdate header@FrameHeader{streamId} bs _ s Stream{streamWindow} = do
     WindowUpdateFrame n <- guardIt $ decodeWindowUpdateFrame header bs
     w <- (n +) <$> atomically (readTVar streamWindow)
@@ -314,6 +321,9 @@
     return s
 
 -- this ordering is important
+stream FrameContinuation _ _ _ _ _ = E.throwIO $ ConnectionError ProtocolError "continue frame cannot come here"
 stream _ _ _ _ (Open Continued{}) _ = E.throwIO $ ConnectionError ProtocolError "an illegal frame follows header/continuation frames"
+-- Ignore frames to streams we have just reset, per section 5.1.
+stream _ _ _ _ st@(Closed (ResetByMe _)) _ = return st
 stream FrameData FrameHeader{streamId} _ _ _ _ = E.throwIO $ StreamError StreamClosed streamId
 stream _ FrameHeader{streamId} _ _ _ _ = E.throwIO $ StreamError ProtocolError streamId
diff --git a/Network/Wai/Handler/Warp/HTTP2/Sender.hs b/Network/Wai/Handler/Warp/HTTP2/Sender.hs
--- a/Network/Wai/Handler/Warp/HTTP2/Sender.hs
+++ b/Network/Wai/Handler/Warp/HTTP2/Sender.hs
@@ -23,6 +23,7 @@
 import Network.Wai.Handler.Warp.HTTP2.Types
 import Network.Wai.Handler.Warp.IORef
 import qualified Network.Wai.Handler.Warp.Settings as S
+import qualified Network.Wai.Handler.Warp.Timeout as T
 import Network.Wai.Handler.Warp.Types
 import Network.Wai.Internal (Response(..))
 import qualified System.PosixCompat.Files as P
@@ -32,6 +33,7 @@
 #else
 import Network.Wai.Handler.Warp.FdCache
 import Network.Wai.Handler.Warp.SendFile (positionRead)
+import System.Posix.IO (openFd, OpenFileFlags(..), defaultFileFlags, OpenMode(ReadOnly), closeFd)
 import System.Posix.Types
 #endif
 
@@ -230,8 +232,12 @@
 #else
 fillResponseBodyGetNext Connection{connWriteBuffer,connBufferSize}
                         ii off lim (ResponseFile _ _ path mpart) = do
-    let Just fdcache = fdCacher ii
-    (fd, refresh) <- getFd fdcache path
+    (fd, refresh) <- case fdCacher ii of
+        Just fdcache -> getFd fdcache path
+        Nothing      -> do
+            fd' <- openFd path ReadOnly Nothing defaultFileFlags{nonBlock=True}
+            th <- T.register (timeoutManager ii) (closeFd fd')
+            return (fd', T.tickle th)
     let datBuf = connWriteBuffer `plusPtr` off
         room = min (connBufferSize - off) lim
     (start, bytes) <- fileStartEnd path mpart
diff --git a/Network/Wai/Handler/Warp/HTTP2/Worker.hs b/Network/Wai/Handler/Warp/HTTP2/Worker.hs
--- a/Network/Wai/Handler/Warp/HTTP2/Worker.hs
+++ b/Network/Wai/Handler/Warp/HTTP2/Worker.hs
@@ -73,7 +73,7 @@
         _ -> do
             setThreadContinue tconf True
             let hasBody = requestMethod req /= H.methodHead
-                       || R.hasBody (responseStatus rsp)
+                       && R.hasBody (responseStatus rsp)
             enqueue outputQ (OResponse strm rsp (Oneshot hasBody)) pri
     return ResponseReceived
 
diff --git a/Network/Wai/Handler/Warp/Response.hs b/Network/Wai/Handler/Warp/Response.hs
--- a/Network/Wai/Handler/Warp/Response.hs
+++ b/Network/Wai/Handler/Warp/Response.hs
@@ -252,7 +252,7 @@
                     hook' = hook
 #else
                 (mfd, hook') <- case mfdc of
-                   -- Windows or settingsFdCacheDuration is 0
+                   -- settingsFdCacheDuration is 0
                    Nothing  -> return (Nothing, hook)
                    Just fdc -> do
                       (fd, fresher) <- F.getFd fdc path
diff --git a/test/BufferPoolSpec.hs b/test/BufferPoolSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/BufferPoolSpec.hs
@@ -0,0 +1,47 @@
+module BufferPoolSpec where
+
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Internal as B (ByteString(PS))
+import Foreign.ForeignPtr (withForeignPtr)
+import Foreign.Marshal.Utils (copyBytes)
+import Foreign.Ptr (plusPtr)
+
+import Test.Hspec (Spec, hspec, shouldBe, describe, it)
+
+import Network.Wai.Handler.Warp.Buffer
+    ( bufferSize
+    , newBufferPool
+    , withBufferPool
+    )
+import Network.Wai.Handler.Warp.Types (Buffer, BufSize)
+
+main :: IO ()
+main = hspec spec
+
+-- Two ByteStrings each big enough to fill a 'bufferSize' buffer (16K).
+wantData, otherData :: B.ByteString
+wantData = B.replicate bufferSize 0xac
+otherData = B.replicate bufferSize 0x77
+
+spec :: Spec
+spec = describe "withBufferPool" $ do
+    it "does not clobber buffers" $ do
+        pool <- newBufferPool
+        -- 'pool' contains B.empty; prime it to contain a real buffer.
+        _ <- withBufferPool pool $ const $ return 0
+        -- 'pool' contains a 16K buffer; fill it with \xac and keep the result.
+        got <- withBufferPool pool $ blitBuffer wantData
+        got `shouldBe` wantData
+        -- 'pool' should now be empty and reallocate, rather than clobber the
+        -- previous buffer.
+        _ <- withBufferPool pool $ blitBuffer otherData
+        got `shouldBe` wantData
+
+-- Fill the Buffer with the contents of the ByteString and return the number of
+-- bytes written.  To be used with 'withBufferPool'.
+blitBuffer :: B.ByteString -> (Buffer, BufSize) -> IO Int
+blitBuffer (B.PS fp off len) (dst, len') = withForeignPtr fp $ \ptr -> do
+    let src = ptr `plusPtr` off
+        n = min len len'
+    copyBytes dst src n
+    return n
diff --git a/warp.cabal b/warp.cabal
--- a/warp.cabal
+++ b/warp.cabal
@@ -1,5 +1,5 @@
 Name:                warp
-Version:             3.1.0
+Version:             3.1.1
 Synopsis:            A fast, light-weight web server for WAI applications.
 License:             MIT
 License-file:        LICENSE
@@ -122,7 +122,8 @@
 
 Test-Suite spec
     Main-Is:         Spec.hs
-    Other-modules:   ConduitSpec
+    Other-modules:   BufferPoolSpec
+                     ConduitSpec
                      ExceptionSpec
                      FdCacheSpec
                      MultiMapSpec