From 04a5b259296a8739534a7c75669bd449e2849c28 Mon Sep 17 00:00:00 2001
From: Krishna Srinivas <krishna@minio.io>
Date: Mon, 9 May 2016 12:19:49 +0530
Subject: [PATCH] Multipart: Minimum part size limit does not apply to the last
 part during CompleteMultipartUpload. (#1518) (#1538)

---
 fs-objects-multipart.go | 14 +++++++++++++-
 server_test.go          | 16 +++++++++++++---
 server_xl_test.go       |  7 +++++++
 xl-objects-multipart.go |  5 +++--
 4 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/fs-objects-multipart.go b/fs-objects-multipart.go
index 0c042c84b..fe0df802b 100644
--- a/fs-objects-multipart.go
+++ b/fs-objects-multipart.go
@@ -73,10 +73,22 @@ func (fs fsObjects) CompleteMultipartUpload(bucket string, object string, upload
 	}
 
 	// Loop through all parts, validate them and then commit to disk.
-	for _, part := range parts {
+	for i, part := range parts {
 		// Construct part suffix.
 		partSuffix := fmt.Sprintf("%.5d.%s", part.PartNumber, part.ETag)
 		multipartPartFile := path.Join(mpartMetaPrefix, bucket, object, uploadID, partSuffix)
+		var fi FileInfo
+		fi, err = fs.storage.StatFile(minioMetaBucket, multipartPartFile)
+		if err != nil {
+			if err == errFileNotFound {
+				return "", InvalidPart{}
+			}
+			return "", err
+		}
+		// All parts except the last part has to be atleast 5MB.
+		if (i < len(parts)-1) && !isMinAllowedPartSize(fi.Size) {
+			return "", PartTooSmall{}
+		}
 		var fileReader io.ReadCloser
 		fileReader, err = fs.storage.ReadFile(minioMetaBucket, multipartPartFile, 0)
 		if err != nil {
diff --git a/server_test.go b/server_test.go
index b43b8dff5..d7e30de3e 100644
--- a/server_test.go
+++ b/server_test.go
@@ -1244,11 +1244,14 @@ func (s *MyAPISuite) TestObjectMultipart(c *C) {
 	c.Assert(len(newResponse.UploadID) > 0, Equals, true)
 	uploadID := newResponse.UploadID
 
+	// Create a byte array of 5MB.
+	data := bytes.Repeat([]byte("0123456789abcdef"), 5*1024*1024/16)
+
 	hasher := md5.New()
-	hasher.Write([]byte("hello world"))
+	hasher.Write(data)
 	md5Sum := hasher.Sum(nil)
 
-	buffer1 := bytes.NewReader([]byte("hello world"))
+	buffer1 := bytes.NewReader(data)
 	request, err = s.newRequest("PUT", testAPIFSCacheServer.URL+"/objectmultiparts/object?uploadId="+uploadID+"&partNumber=1", int64(buffer1.Len()), buffer1)
 	request.Header.Set("Content-Md5", base64.StdEncoding.EncodeToString(md5Sum))
 	c.Assert(err, IsNil)
@@ -1258,7 +1261,14 @@ func (s *MyAPISuite) TestObjectMultipart(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(response1.StatusCode, Equals, http.StatusOK)
 
-	buffer2 := bytes.NewReader([]byte("hello world"))
+	// Byte array one 1 byte.
+	data = []byte("0")
+
+	hasher = md5.New()
+	hasher.Write(data)
+	md5Sum = hasher.Sum(nil)
+
+	buffer2 := bytes.NewReader(data)
 	request, err = s.newRequest("PUT", testAPIFSCacheServer.URL+"/objectmultiparts/object?uploadId="+uploadID+"&partNumber=2", int64(buffer2.Len()), buffer2)
 	request.Header.Set("Content-Md5", base64.StdEncoding.EncodeToString(md5Sum))
 	c.Assert(err, IsNil)
diff --git a/server_xl_test.go b/server_xl_test.go
index d852a03de..cbe07bc3d 100644
--- a/server_xl_test.go
+++ b/server_xl_test.go
@@ -1279,6 +1279,13 @@ func (s *MyAPIXLSuite) TestObjectMultipart(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(response1.StatusCode, Equals, http.StatusOK)
 
+	// Create a byte array of 1 byte.
+	data = []byte("0")
+
+	hasher = md5.New()
+	hasher.Write(data)
+	md5Sum = hasher.Sum(nil)
+
 	buffer2 := bytes.NewReader(data)
 	request, err = s.newRequest("PUT", testAPIXLServer.URL+"/objectmultiparts/object?uploadId="+uploadID+"&partNumber=2", int64(buffer2.Len()), buffer2)
 	request.Header.Set("Content-Md5", base64.StdEncoding.EncodeToString(md5Sum))
diff --git a/xl-objects-multipart.go b/xl-objects-multipart.go
index b3f8ea81c..9fa356334 100644
--- a/xl-objects-multipart.go
+++ b/xl-objects-multipart.go
@@ -124,7 +124,7 @@ func (xl xlObjects) CompleteMultipartUpload(bucket string, object string, upload
 	var wg = &sync.WaitGroup{}
 
 	// Loop through all parts, validate them and then commit to disk.
-	for _, part := range parts {
+	for i, part := range parts {
 		// Construct part suffix.
 		partSuffix := fmt.Sprintf("%.5d.%s", part.PartNumber, part.ETag)
 		multipartPartFile := path.Join(mpartMetaPrefix, bucket, object, uploadID, partSuffix)
@@ -136,7 +136,8 @@ func (xl xlObjects) CompleteMultipartUpload(bucket string, object string, upload
 			}
 			return "", err
 		}
-		if !isMinAllowedPartSize(fi.Size) {
+		// All parts except the last part has to be atleast 5MB.
+		if (i < len(parts)-1) && !isMinAllowedPartSize(fi.Size) {
 			return "", PartTooSmall{}
 		}
 		// Update metadata parts.