(400) Bad Request - The specified block list is invalid. ErrorCode:InvalidBlockList

Which service(blob, file, queue, table) does this issue concern?

Blob

Which version of the SDK was used?

WindowsAzure.Storage 6.2.0

Which platform are you using? (ex: .NET Core 2.1)

.Net Framework 4.5.1

What problem was encountered?

Getting this 400 Bad Request with message in transient fashion randomly.

The specified block list is invalid. 

ErrorCode: InvalidBlockList

API being used:

public virtual void UploadFromByteArray(byte[] buffer, int index, int count, AccessCondition accessCondition = null, BlobRequestOptions options = null, OperationContext operationContext = null);

How can we reproduce the problem in the simplest way?

Execute this scenario and run multiple times with different threads uploading together 100MB or so type of data.

Have you found a mitigation/solution?

Not Yet

[moroz-slavomir]

We are also facing the same issue and have done a little bit of an investigation in the application insights. Here is what we have found.

Trivia

The Put Block operation creates a new block to be committed as part of a blob.

The Put Block List operation writes a blob by specifying the list of block IDs that make up the blob. In order to be written as part of a blob, a block must have been successfully written to the server in a prior Put Block operation.

Successful upload

Consists of 1-n Put Block operations and final Put Block List operation.

Failed upload

In the failed upload the final Put Block List fails with message The specified block list is invalid.

Possible cause

It seems that storage SDK is executing the Put Block List in parallel with the Put Block and does not wait for the Put Block to finish.

Successful upload timeline Upload #1 - 1 block 2020-12-07T12:53:09.8442922Z + 0.01 2020-12-07T12:53:09.854617Z

Upload #2 - many blocks 2020-12-07T13:17:51.3556283Z + 0.371 2020-12-07T13:17:51.7276951Z

Failed upload timeline Upload #3 - 2 blocks 2020-11-27T13:27:44.3833279Z + 0.03 2020-11-27T13:27:44.3835717Z

Upload #4 - 2 blocks 2020-11-27T13:38:11.1370163Z + 0.105 2020-11-27T13:38:11.1372083Z

We are also using OpenWriteAsync() as was @angelcalvasp in their example, so my guess is the problem lies in the BlobWriteStream.

CommitAsync is calling PutBlockListAsync (the final operation) and before that it runs FlushAsync. It appears the FlushAsync should block until all pending block writes are finished, but I guess it doesn’t work properly.

Edited: SDK Version: 11.2.2 Platform: .Net Framework 4.7.2

[kasobol-msft]

The fix is available on Nuget. Version 11.2.3.