Set-RsDataSourceReferenceGlobal.ps1

<#
 # Run these two lines to download the Microsoft Powershell Tools.  
 
 Project URL:  https://github.com/Microsoft/ReportingServicesTools

[Net.ServicePointManager]::SecurityProtocol = "tls12, tls11, tls"
Invoke-Expression (Invoke-WebRequest https://raw.githubusercontent.com/Microsoft/ReportingServicesTools/master/Install.ps1)

#>

function Set-RsDataSourceReferenceGlobal {
    param (
        [string] $ReportServerUri,
        [string] $ServerFolder,
        [string] $DataSourcePath
    )

    Write-Host 'Scanning ' $ServerFolder
    $serverReports = Get-RsFolderContent -ReportServerUri $ReportServerUri -RsFolder $ServerFolder | ?{$_.TypeName -eq 'Report'} | Select-Object -ExpandProperty Name

    $serverReports | %{
        $report = $ServerFolder + '/' + $_
        $ds = Get-RsItemDataSource -ReportServerUri $ReportServerUri -RsItem $report
        Write-Host 'Updating sources in ' $report
        $ds | %{ Set-RsDataSourceReference -ReportServerUri $ReportServerUri -Path $report -DataSourceName $_.Name -DataSourcePath $DataSourcePath }
    }
            
    <#
    $reportsToAdd = $localReports | ?{$serverReports -notcontains $_ }
    $reportsToAdd | %{
        Write-Host 'Adding report ' $_ 
        $localPath = $LocalFolder + '\' + $_
        Write-RsCatalogItem -ReportServerUri $ReportServerUri -Path $localPath -RsFolder $ServerFolder -Overwrite
    }
    #>


    $serverFolders = Get-RsFolderContent -ReportServerUri $ReportServerUri -RsFolder $ServerFolder | ?{$_.TypeName -eq 'Folder'} | Select-Object -Expand Name
    
    foreach ($folder in $serverFolders) {
        $f = $ServerFolder + '/' + $folder
        Set-RsDataSourceReferenceGlobal -ReportServerUri $ReportServerUri -ServerFolder $f -DataSourcePath $DataSourcePath
    }
}