[Storage] Fix file upload with Oauth issue (#24291)

* Fix issue #24289

* Respect the actualy bytes number read from file stream.

Author: blueww

src/Storage/Storage.Management/ChangeLog.md

@@ -18,6 +18,8 @@
         - Additional information about change #1
 -->
 ## Upcoming Release
+* Fixed upload file with OAuth authentication issue [#24289] 
+    - `Set-AzStorageFileContent`
 
 ## Version 6.1.2
 * Fixed parser logic when downloading blob from managed disk account with Sas Uri and bearer token on Linux and MacOS

src/Storage/Storage/File/Cmdlet/SetAzureStorageFileContent.cs

@@ -239,29 +239,27 @@ await DataMovementTransferHelper.DoTransfer(() =>
                         using (FileStream stream = File.OpenRead(localFile.FullName))
                         {
                             byte[] buffer = null;
-                            long lastBlockSize = 0;
-                            for (long offset = 0; offset < fileSize; offset += blockSize)
+                            for (long offset = 0; offset < fileSize;)
                             {
-                                long currentBlockSize = offset + blockSize < fileSize ? blockSize : fileSize - offset;
+                                long targetBlockSize = offset + blockSize < fileSize ? blockSize : fileSize - offset;
 
-                                // Only need to create new buffer when chunk size change
-                                if (currentBlockSize != lastBlockSize)
-                                {
-                                    buffer = new byte[currentBlockSize];
-                                    lastBlockSize = currentBlockSize;
-                                }
-                                await stream.ReadAsync(buffer: buffer, offset: 0, count: (int)currentBlockSize);
+                                // create new buffer, the old buffer will be GC
+                                buffer = new byte[targetBlockSize];
+
+                                int actualBlockSize = await stream.ReadAsync(buffer: buffer, offset: 0, count: (int)targetBlockSize);
                                 if (!fipsEnabled && hash != null)
                                 {
-                                    hash.AppendData(buffer);
+                                    hash.AppendData(buffer, 0, actualBlockSize);
                                 }
 
                                 Task task = UploadFileRangAsync(fileClient,
-                                    new HttpRange(offset, currentBlockSize),
-                                    new MemoryStream(buffer),
+                                    new HttpRange(offset, actualBlockSize),
+                                    new MemoryStream(buffer, 0, actualBlockSize),
                                     progressHandler);
                                 runningTasks.Add(task);
 
+                                offset += actualBlockSize;
+
                                 // Check if any of upload range tasks are still busy
                                 if (runningTasks.Count >= maxWorkers)
                                 {