add post about WSL/ext4

content/posts/2024-03-21-mount-ext4-windows-without-wsl/index.md

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+---
+cover:
+  #image: "posts/2024-03-17-pi-zero2-cctv/banner.jpg"
+  #relative: false
+  #alt: "Ubuntu Login Prompt That Says Login Failed."
+  #caption: "I'm sorry Dave, I'm afraid I can't do that."
+author: "Eugene de Beste"
+title: "When WSL Fails You: Mounting ext4 Linux Partitions on Windows When They're on the Same Drive as C:"
+date: "2024-03-21"
+description: Still dual-booting Windows and Linux for experimentation reasons, I tried copying files from my Linux partition (on the same SSD as C:) to Windows. I quickly found that it's not supported in WSL, so I had to find a workaround.
+categories:
+  - Technology
+tags:
+  - RaspberryPi
+
+
+showtoc: true
+TocOpen: true
+---
+
+I'm one of the (probably) few people that still dual-boot Windows and Linux. There are plenty things that are easier for me to do on a Linux host rather than in Windows, even with WSL being quite useful these days. An example of this is virtualization related experiments (specifically with Qemu/KVM).
+
+A little while back I started writing an upcoming blog post while booted into Linux and took some screenshots that I wanted to use for it. Like a rookie, I pushed the draft of the post to git, but didn't include the screenshots.
+
+While continuing on with writing the post, now in Windows, I needed a way to copy the files from the partition that lives on the same SSD as my Windows C: partition to said C: drive.
+
+---
+
+# The Broken Way
+
+Ez-pz, I'll just use the new fancy WSL features that allow this, right? _**WRONG**_.
+
+WSL includes support for mounting Linux filesystems with the following command:
+
+```powershell
+wsl --mount \\.\PHYSICALDRIVE<number> [--partition <number>]
+```
+
+Identifying the desired **PHYSICALDRIVE** number of the target disk can be done using `wmic`:
+
+```text
+### List disk drives
+PS> wmic diskdrive list brief
+
+### Output:
+Caption                             DeviceID            Model                               Partitions  Size
+ST1000DM003-1SB10C                  \\.\PHYSICALDRIVE2  ST1000DM003-1SB10C                  1           1000202273280
+Samsung SSD 860 EVO 1TB             \\.\PHYSICALDRIVE0  Samsung SSD 860 EVO 1TB             1           1000202273280
+Samsung SSD 870 EVO 1TB             \\.\PHYSICALDRIVE1  Samsung SSD 870 EVO 1TB             1           1000202273280
+Seagate FireCuda 530 ZP2000GM30023  \\.\PHYSICALDRIVE4  Seagate FireCuda 530 ZP2000GM30023  3           2000396321280
+Samsung SSD 870 EVO 1TB             \\.\PHYSICALDRIVE3  Samsung SSD 870 EVO 1TB             1           1000202273280
+```
+
+The _Seagate FireCuda_ drive is the one I care about, so I need to target `\\.\PHYSICALDRIVE4`.
+
+Figuring out the partition is also relatively simple with `diskpart`:
+
+```powershell
+diskpart
+list disk
+sel disk <number>
+list part
+```
+
+Which, for me, results in:
+
+```text
+  Partition ###  Type              Size     Offset
+  -------------  ----------------  -------  -------
+  Partition 1    System             100 MB  1024 KB
+  Partition 2    Reserved            16 MB   101 MB
+  Partition 3    Primary           1569 GB   117 MB
+  Partition 4    Unknown            293 GB  1569 GB   <--- this guy
+```
+
+Now that I know I need `\\.\PHYSICALDRIVE4` and partition `4`, I attempt to mount:
+
+```powershell
+wsl --mount \\.\PHYSICALDRIVE4 --partition 4
+```
+
+And am presented with the wonderful error message:
+
+```text
+Error code: Wsl/Service/AttachDisk/WSL_E_ELEVATION_NEEDED_TO_MOUNT_DISK
+```
+
+😔
+
+There are others afflicted by this terrible terrible error, too: https://github.com/microsoft/WSL/issues/8773
+
+---
+
+# The Working Way
+
+Not wanting to spend too much time on it, I looked for alternatives. I remember using a tool called Ext2Fsd baaaaack in the day to accomplish this, but the builds are now very out of date, wth the [last update being circa 2017](https://sourceforge.net/projects/ext2fsd/files/Ext2fsd/0.69/).
+
+After some Google-fu, I found an experimental revival fork of the project here: https://github.com/bobranten/Ext4Fsd. These diligent folk worked on signing the driver for use in Windows 10 and 11. I'll let their `README.md` do the explaining:
+
+> This is a branch of the Ext2Fsd project by Matt Wu where I try to
+> implement support for metadata checksums and jbd2. I have also
+> updated the project so it can be compiled with Visual Studio 2019
+> and Visual Studio 2022.
+> The current status of the development is that all metadata checksums
+> is implemented and jbd2 is ported to support 64-bit blocknumbers.
+> The driver is now ready to be tested!
+
+{{< notice warning >}}
+I want to emphasise that the authors claim that it is currently in testing, so odd behaviour or data loss MAY be a risk.
+
+It worked just fine for my needs, though!
+{{</ notice >}}
+
+Using it is super simple, just like I remember:
+
+1. Download the latest `-setup.exe` release package from https://github.com/bobranten/Ext4Fsd/releases.
+2. Install the package.
+3. Open the newly installed `Ext2 Volume Manager` application.
+4. Right-click the ext4 volume that you want to mount and press **Assign Drive Letter**.
+5. Your ext4 partition will automagically get an un-used drive letter associated, like plugging in a USB drive, and the ext4 volume will be available for you to use in Windows!
+
+![Mounting the ext4 Volume](./mounting.png)
+
+To revert (unmount):
+
+1. Right-click the mounted target volume in `Ext2 Volume Manager`.
+2. Click **Change Drive Letter**.
+3. Select the drive letter in the box and click **Remove**, followed by **Done**.