From 9a9a13418894f4200c21943984d95c326ea6823a Mon Sep 17 00:00:00 2001
From: Ivan Andreev <ivandeex@gmail.com>
Date: Fri, 18 Sep 2020 17:58:44 +0300
Subject: [PATCH] Merge pull request #4608 from ivandeex/pr-chunker-crypt

chunker: fix upload over crypt (fixes #4570)
---
 backend/chunker/chunker.go  | 8 +++++++-
 fstest/test_all/config.yaml | 4 ++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/backend/chunker/chunker.go b/backend/chunker/chunker.go
index 5bdfa7a4d..a8ee098f3 100644
--- a/backend/chunker/chunker.go
+++ b/backend/chunker/chunker.go
@@ -958,6 +958,8 @@ func (f *Fs) put(ctx context.Context, in io.Reader, src fs.ObjectInfo, remote st
 		}
 		info := f.wrapInfo(src, chunkRemote, size)
 
+		// Refill chunkLimit and let basePut repeatedly call chunkingReader.Read()
+		c.chunkLimit = c.chunkSize
 		// TODO: handle range/limit options
 		chunk, errChunk := basePut(ctx, wrapIn, info, options...)
 		if errChunk != nil {
@@ -1166,10 +1168,14 @@ func (c *chunkingReader) updateHashes() {
 func (c *chunkingReader) Read(buf []byte) (bytesRead int, err error) {
 	if c.chunkLimit <= 0 {
 		// Chunk complete - switch to next one.
+		// Note #1:
 		// We might not get here because some remotes (eg. box multi-uploader)
 		// read the specified size exactly and skip the concluding EOF Read.
 		// Then a check in the put loop will kick in.
-		c.chunkLimit = c.chunkSize
+		// Note #2:
+		// The crypt backend after receiving EOF here will call Read again
+		// and we must insist on returning EOF, so we postpone refilling
+		// chunkLimit to the main loop.
 		return 0, io.EOF
 	}
 	if int64(len(buf)) > c.chunkLimit {
diff --git a/fstest/test_all/config.yaml b/fstest/test_all/config.yaml
index 6d9cd3a63..9581d3b5e 100644
--- a/fstest/test_all/config.yaml
+++ b/fstest/test_all/config.yaml
@@ -71,6 +71,10 @@ backends:
    remote:   "TestChunkerChunk50bSHA1HashS3:"
    fastlist: true
    maxfile:  1k
+ - backend:  "chunker"
+   remote:   "TestChunkerOverCrypt:"
+   fastlist: true
+   maxfile:  6k
  - backend:  "chunker"
    remote:   "TestChunkerChunk50bMD5QuickS3:"
    fastlist: true