File not being truncated on shared folder - WinXP 32 SP3 guest on WinXP 32 SP3 host, VBox 4.1.0+Guest Additions 4.1.0

[DfDf]

When a file on shared folder (for example - even a plain text) is being edited in Far (​http://www.farmanager.com) and when tail of file (for ex. - 4-5 last lines) is being deleted, after that file is saved - the tail remains in file as it was not deleted.

Steps to reproduce:

1. Map a shared folder with full access and automount in guest OS.
   
2. Put a short (about 1K) plain text file to shared folder.
   
3. Download far manager from ​http://www.farmanager.com (open source).
   
4. Install FAR in guest OS.
   
5. Change to shared folder in guest OS via FAR. (Alt-F2)
   
6. Press F4 (edit) on file from step 2.
   
7. Remove several last lines (4-5) from the end of file (in any way - for ex. by Ctrl-Y).
   
8. Press F2 to save changes (or ESC, and than confirm save).
   
9. Quit editor by ESC.
   
10. Open file in host OS (or even again in guest OS) in notepad. Observe the BUG - deleted lines are still present in the file AND file size IS NOT CHANGED.
    

FAR uses this steps to write to file:

1. File is being read to memory, than closed.
   
2. User edit the file and presses F2 to write to file.
   
3. File is being reopened with write access.
   
4. File is truncated to 0 bytes length.
   
5. Memory is being written back to file.
   

At this point if file resides on shared folder and edited from guest OS - the BUG arrives.

[sunlover]

Thanks for the report. The problem is fixed in:

​http://www.virtualbox.org/download/testcase/VBoxGuestAdditions-r73157.iso

Please install the new additions.

Actually this is the same problem as of ​http://www.virtualbox.org/ticket/9276