When mounted through a FUSE implementation (we're using puniverse/javafs), trying to write a new file always fails with NoSuchFileException but creates an empty file

[guss77]

As explained in [this StackOverflow answer[(https://stackoverflow.com/questions/32212121/fuse-open-system-call-mechanism#), the way FUSE handles open(..,O_CREAT) (write to a file, creating if needed) is to call getattr() (which is implemented in puniverse/javafs as FileSystemProvider.readAttributes()) and if that fails to call create() (implemented in puniverse/javafs as FileSystemProvider.newByteChannel()) followed by fgetattr() - to check that the file was created correctly and it has the requested permissions.

Unfortunately, in Amazon-S3-FileSystem-NIO2, calling FileSystemProvider.newByteChannel() does not create a real object in S3 (at least not if multipart upload is disabled, which it is by default - I didn't check what happens with multipart upload). Instead it creates a new temporary file and an S3SeekableByteChannel instance that is not recorded anywhere - if the byte channel ever gets closed, only then a new S3 object is created. This can be viewed as a violation of the FileSystemProvider contract that specifies that newByteChannel() "Opens or creates a file" - the method opens an existing file, but if none exists it does not create a new file in any meaningful way viewable by other FileSystemProvider methods.

So when FUSE calls readAttributes() on the newly created file, the implementation throws a NoSuchFileException instead of returning the attributes of the supposedly newly created file.