diff --git a/src/SourceBuild/tarball/patches/roslyn/0004-Build-more-projects-during-source-build.patch b/src/SourceBuild/tarball/patches/roslyn/0004-Build-more-projects-during-source-build.patch
new file mode 100644
index 000000000..4cd594d3d
--- /dev/null
+++ b/src/SourceBuild/tarball/patches/roslyn/0004-Build-more-projects-during-source-build.patch
@@ -0,0 +1,125 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Davis Goodin <dagood@microsoft.com>
+Date: Thu, 14 Oct 2021 18:24:18 -0500
+Subject: [PATCH] Build more projects during source-build
+
+Use Roslyn.sln, not Compilers.sln, to build more projects during
+source-build. Update ExcludeFromSourceBuild properties to include more
+projects and exclude a few projects that shouldn't be in source-build.
+
+The newly included projects are used by downstream repos.
+
+PR for applying this patch: https://github.com/dotnet/roslyn/pull/57165
+---
+ eng/SourceBuild.props                                       | 2 +-
+ .../Core/Tests}/Directory.Build.props                       | 0
+ .../CodeAnalysis.Debugging}/Directory.Build.props           | 0
+ src/Dependencies/Microsoft.NetFX20/Directory.Build.props    | 6 ++++++
+ src/Dependencies/PooledObjects/Directory.Build.props        | 6 ++++++
+ src/Features/LanguageServer/Directory.Build.props           | 6 ++++++
+ src/Features/Lsif/Directory.Build.props                     | 6 ++++++
+ src/NuGet/VisualStudio/Directory.Build.props                | 6 ++++++
+ .../Microsoft.CodeAnalysis.Workspaces.MSBuild.csproj        | 2 --
+ 9 files changed, 31 insertions(+), 3 deletions(-)
+ rename src/{Dependencies => CodeStyle/Core/Tests}/Directory.Build.props (100%)
+ rename src/{Features => Dependencies/CodeAnalysis.Debugging}/Directory.Build.props (100%)
+ create mode 100644 src/Dependencies/Microsoft.NetFX20/Directory.Build.props
+ create mode 100644 src/Dependencies/PooledObjects/Directory.Build.props
+ create mode 100644 src/Features/LanguageServer/Directory.Build.props
+ create mode 100644 src/Features/Lsif/Directory.Build.props
+ create mode 100644 src/NuGet/VisualStudio/Directory.Build.props
+
+diff --git a/eng/SourceBuild.props b/eng/SourceBuild.props
+index 182f8a9cdb1..92e316a4744 100644
+--- a/eng/SourceBuild.props
++++ b/eng/SourceBuild.props
+@@ -11,7 +11,7 @@
+   -->
+   <Target Name="ConfigureInnerBuildArg" BeforeTargets="GetSourceBuildCommandConfiguration">
+     <PropertyGroup>
+-      <InnerBuildArgs>$(InnerBuildArgs) /p:Projects="$(InnerSourceBuildRepoRoot)\Compilers.sln"</InnerBuildArgs>
++      <InnerBuildArgs>$(InnerBuildArgs) /p:Projects="$(InnerSourceBuildRepoRoot)\Roslyn.sln"</InnerBuildArgs>
+     </PropertyGroup>
+   </Target>
+ 
+diff --git a/src/Dependencies/Directory.Build.props b/src/CodeStyle/Core/Tests/Directory.Build.props
+similarity index 100%
+rename from src/Dependencies/Directory.Build.props
+rename to src/CodeStyle/Core/Tests/Directory.Build.props
+diff --git a/src/Features/Directory.Build.props b/src/Dependencies/CodeAnalysis.Debugging/Directory.Build.props
+similarity index 100%
+rename from src/Features/Directory.Build.props
+rename to src/Dependencies/CodeAnalysis.Debugging/Directory.Build.props
+diff --git a/src/Dependencies/Microsoft.NetFX20/Directory.Build.props b/src/Dependencies/Microsoft.NetFX20/Directory.Build.props
+new file mode 100644
+index 00000000000..6eef643958f
+--- /dev/null
++++ b/src/Dependencies/Microsoft.NetFX20/Directory.Build.props
+@@ -0,0 +1,6 @@
++<Project>
++  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
++  <PropertyGroup>
++    <ExcludeFromSourceBuild>true</ExcludeFromSourceBuild>
++  </PropertyGroup>
++</Project>
+diff --git a/src/Dependencies/PooledObjects/Directory.Build.props b/src/Dependencies/PooledObjects/Directory.Build.props
+new file mode 100644
+index 00000000000..6eef643958f
+--- /dev/null
++++ b/src/Dependencies/PooledObjects/Directory.Build.props
+@@ -0,0 +1,6 @@
++<Project>
++  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
++  <PropertyGroup>
++    <ExcludeFromSourceBuild>true</ExcludeFromSourceBuild>
++  </PropertyGroup>
++</Project>
+diff --git a/src/Features/LanguageServer/Directory.Build.props b/src/Features/LanguageServer/Directory.Build.props
+new file mode 100644
+index 00000000000..6eef643958f
+--- /dev/null
++++ b/src/Features/LanguageServer/Directory.Build.props
+@@ -0,0 +1,6 @@
++<Project>
++  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
++  <PropertyGroup>
++    <ExcludeFromSourceBuild>true</ExcludeFromSourceBuild>
++  </PropertyGroup>
++</Project>
+diff --git a/src/Features/Lsif/Directory.Build.props b/src/Features/Lsif/Directory.Build.props
+new file mode 100644
+index 00000000000..6eef643958f
+--- /dev/null
++++ b/src/Features/Lsif/Directory.Build.props
+@@ -0,0 +1,6 @@
++<Project>
++  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
++  <PropertyGroup>
++    <ExcludeFromSourceBuild>true</ExcludeFromSourceBuild>
++  </PropertyGroup>
++</Project>
+diff --git a/src/NuGet/VisualStudio/Directory.Build.props b/src/NuGet/VisualStudio/Directory.Build.props
+new file mode 100644
+index 00000000000..6eef643958f
+--- /dev/null
++++ b/src/NuGet/VisualStudio/Directory.Build.props
+@@ -0,0 +1,6 @@
++<Project>
++  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
++  <PropertyGroup>
++    <ExcludeFromSourceBuild>true</ExcludeFromSourceBuild>
++  </PropertyGroup>
++</Project>
+diff --git a/src/Workspaces/Core/MSBuild/Microsoft.CodeAnalysis.Workspaces.MSBuild.csproj b/src/Workspaces/Core/MSBuild/Microsoft.CodeAnalysis.Workspaces.MSBuild.csproj
+index 3bd6d6398e3..2edf2da6d1a 100644
+--- a/src/Workspaces/Core/MSBuild/Microsoft.CodeAnalysis.Workspaces.MSBuild.csproj
++++ b/src/Workspaces/Core/MSBuild/Microsoft.CodeAnalysis.Workspaces.MSBuild.csproj
+@@ -7,8 +7,6 @@
+     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+     <TargetFrameworks>netcoreapp3.1;net472</TargetFrameworks>
+     <DefineConstants>$(DefineConstants);WORKSPACE_MSBUILD</DefineConstants>
+-    <ExcludeFromSourceBuild>true</ExcludeFromSourceBuild>
+-
+     <!-- NuGet -->
+     <IsPackable>true</IsPackable>
+     <PackageDescription>
diff --git a/src/SourceBuild/tarball/patches/roslyn/0005-Exclude-src-Dependencies-from-source-build.patch b/src/SourceBuild/tarball/patches/roslyn/0005-Exclude-src-Dependencies-from-source-build.patch
new file mode 100644
index 000000000..0d7e959a3
--- /dev/null
+++ b/src/SourceBuild/tarball/patches/roslyn/0005-Exclude-src-Dependencies-from-source-build.patch
@@ -0,0 +1,45 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Davis Goodin <dagood@microsoft.com>
+Date: Fri, 15 Oct 2021 02:41:32 -0500
+Subject: [PATCH] Exclude src/Dependencies from source-build
+
+This makes source-build stop producing the Microsoft.CodeAnalysis.Collections package. Downstream repos (MSBuild) can't safely use a source-built version.
+
+PR for applying this patch: https://github.com/dotnet/roslyn/pull/57165
+---
+ .../{CodeAnalysis.Debugging => }/Directory.Build.props      | 0
+ src/Dependencies/Microsoft.NetFX20/Directory.Build.props    | 6 ------
+ src/Dependencies/PooledObjects/Directory.Build.props        | 6 ------
+ 3 files changed, 12 deletions(-)
+ rename src/Dependencies/{CodeAnalysis.Debugging => }/Directory.Build.props (100%)
+ delete mode 100644 src/Dependencies/Microsoft.NetFX20/Directory.Build.props
+ delete mode 100644 src/Dependencies/PooledObjects/Directory.Build.props
+
+diff --git a/src/Dependencies/CodeAnalysis.Debugging/Directory.Build.props b/src/Dependencies/Directory.Build.props
+similarity index 100%
+rename from src/Dependencies/CodeAnalysis.Debugging/Directory.Build.props
+rename to src/Dependencies/Directory.Build.props
+diff --git a/src/Dependencies/Microsoft.NetFX20/Directory.Build.props b/src/Dependencies/Microsoft.NetFX20/Directory.Build.props
+deleted file mode 100644
+index 6eef643958f..00000000000
+--- a/src/Dependencies/Microsoft.NetFX20/Directory.Build.props
++++ /dev/null
+@@ -1,6 +0,0 @@
+-<Project>
+-  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
+-  <PropertyGroup>
+-    <ExcludeFromSourceBuild>true</ExcludeFromSourceBuild>
+-  </PropertyGroup>
+-</Project>
+diff --git a/src/Dependencies/PooledObjects/Directory.Build.props b/src/Dependencies/PooledObjects/Directory.Build.props
+deleted file mode 100644
+index 6eef643958f..00000000000
+--- a/src/Dependencies/PooledObjects/Directory.Build.props
++++ /dev/null
+@@ -1,6 +0,0 @@
+-<Project>
+-  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
+-  <PropertyGroup>
+-    <ExcludeFromSourceBuild>true</ExcludeFromSourceBuild>
+-  </PropertyGroup>
+-</Project>