File contents differs on mounted Windows drive between Windows and WSL

[pmsanford]

• Your Windows build number: (Type ver at a Windows Command Prompt)
  Microsoft Windows [Version 10.0.18898.1000]

• What you're doing and what's happening:
  My setup:

• Mount location is changed from /mnt to /, so for example C:\Users is at /c/Users
• I have a directory containing source code for various projects under C:\Users\account\dev
• I have a symlink from /c/Users/account/dev to /home/account/dev
• I edit files under ~/dev with editors in Windows, but run tests/servers/etc under WSL

Please note that I am not attempting to edit files under the WSL filesystem from windows; I am editing files in the Windows filesystem from windows and then accessing them from within WSL.

The specific problem I'm posting about is that occasionally when I'm editing files in IntelliJ, the content of the files will stop changing when viewed from WSL. This only started happening with the latest fast ring updates. I haven't noticed this happening with files edited by things other than IntelliJ, but around the latest update I switched to editing python/js with VS Code's remote WSL extension, so that could be a red herring.

If I restart LxssManager or reboot the computer, this is fixed for a while. I have not been able to identify anything specific that triggers this.

Another ongoing issue (which is not a WSL issue) is that editing files with IntelliJ resets their permissions to whatever the mask for the mounted drive is is. I assume (but have not confirmed) this is because IntelliJ writes to files by deleting and recreating them. This could be why only files edited in IntelliJ exhibit this problem.

The file content is the same no matter what method I use to open it (meaning git, with a WSL-side editor like vim, with cat, the binaries built by maven, etc).

• What's wrong / what should be happening instead:
  Changes made to files in C:\Users\account\dev on Windows should be reflected immediately on /c/Users/account/dev in WSL..

[craigloewen-msft]

Hi @pmsanford , could you provide more of a repro? Is there a specific way that the changes stop being noticed in WSL? As in, are you already running a server on these files and the changes aren't going over to WSL while the server is running (and if so, which server?), or are you not seeing the changes using commands like cat, etc.

Any more description, or list of command line arguments you use would be helpful!

Thanks!

[pmsanford]

@mscraigloewen Unfortunately I haven't been able to notice a specific set of steps (other than editing in IntelliJ as mentioned before) as the way this manifests is usually fairly confusing and I don't notice until I've made other changes troubleshooting. This has only happened 4 or 5 times so far.

This occurs in a Java project I'm working on, so the usual way I discover it is that I'll make some changes (in IntelliJ on Windows), rebuild the project (on WSL), run it (on WSL), and the changes I've made will not be reflected in the output of the program. I'll then go back to the IDE (running in Windows) and check that the changes are present and saved; I can view them with something like Notepad, VS Code (also running in Windows), or Get-Content in PowerShell and the changes are reflected there as well. If I view them using anything on the WSL side (cat, vim, etc) the content does not match what I see from apps on the Windows side (it reflects the content from before my edits). Restarting LxssManager (or my entire PC) fixes this and they sync up again.

I haven't seen this since the last fast ring update (18908.1000) but I've also been on PTO. Will update if this happens again and try to nail down more specifically what I was doing before it happened.

[craigloewen-msft]

Okay great! Anything reproducible that we could quickly test would be helpful. In the meantime I'll try out your setup and see if I can repro. Please ping this thread if you have any updates!

[pmsanford]

This happened again today - I had been editing the same Java project with VS Code Insiders using the WSL Remote extension and I switched to IntelliJ editing by local file path and some of the first changes I made caused a desync. I didn't do anything special - I edited a test file and saved and they went out of sync. I realized I didn't post my wsl.conf in the initial post:

[automount]
root = /
options = "metadata,umask=22,fmask=11"

and my current ver: Microsoft Windows [Version 10.0.18908.1000]

ETA: This initially started happening before the vs code remote extensions were released - I don't think that's related.

[craigloewen-msft]

Yup I was able to repro your problem! Here's the steps I used:

• Set my wsl.conf file to the one that you had and restarted my distro
• Ran the commands:

cd wsldev3
notepad.exe test.c

• Edited the file in notepad in test.c and saved it
• cat ./test.c gives the earlier version of the file

We'll take a look at this bug! Thanks for posting the issue.
@SvenGroot

[canselcik]

I am having this issue as well. It is a recent regression as far as I can tell from my timeline.

Calling sync; sync in WSL seemed to have taken care of if at least once, but it keeps coming back and at this point it doesn't sync using that workaround either. So that was probably a coincidence.

Looks like IntelliJ is able to know that the write failed, however the reason isn't displayed. This might have something to do with the use of inotify inside WSL because as far as I can tell, if the program using inotify inside WSL is terminated, and the file is edited again in Windows, the write succeeds and the files in question go in sync.