`ff` escapes in filename when copying over an existing file

[savchenko]

Describe the bug

Copying a file from W10 guest to Linux host, over one with an existing filename, leads to a new file with ff escapes in its name.

ls -al
total 52
drwxr-xr-x 2 user user  4096 Apr 21 01:53  .
drwxr-xr-x 5 user user  4096 Apr 21 01:42  ..
-rw-rw-r-- 1 user user  4077 Apr 21  2022 ''$'\377\377\377\377\377\377\377\377'
-rw-rw-r-- 1 user user 34991 Apr 21 01:42  cmd.bat
-rw-rw-r-- 1 user user  4080 Apr 21  2022  powershell.ps1

To Reproduce

Copy file with an existing filename the mounted share

Expected behavior

Warning that such file exists.

Screenshots

Host:

• Distro: Debian Testing
• Kernel version: v5.16.18
• QEMU version: v6.2+dfsg-3
• QEMU command line: N/A (using virt-manager v4.0.0)
• libvirt version: v8.1.0-2

• libvirt XML file: Under the spoiler below

  (click me)

  ```xml win10 48abf6bc-9d03-48cd-8839-5163d8f74310 16777216 16777216 8 hvm destroy restart destroy /usr/bin/qemu-system-x86_64

VM:

• Windows version: 10.0.19044 Build 19044 (21H2)
• Which driver has a problem: ?
• Driver version or commit hash that was used to build the driver: v0.1.215-2

Additional context

VShare configuration:

<filesystem type="mount" accessmode="passthrough">
  <driver type="virtiofs" queue="1024"/>
  <binary path="/usr/lib/qemu/virtiofsd"/>
  <source dir="/tmp/vshare"/>
  <target dir="vshare"/>
  <alias name="fs0"/>
  <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
</filesystem>

[viktor-prutyanov]

Hi @savchenko ,

could you please write detailed steps to reproduce the issue?

As for me, overwrite works:

C:\Users\Administrator>echo Hello > Z:\hello.txt

C:\Users\Administrator>echo Hello > hello.txt

C:\Users\Administrator>copy hello.txt Z:\hello.txt
Overwrite Z:\hello.txt? (Yes/No/All): y
        1 file(s) copied.

C:\Users\Administrator>Z:

Z:\>dir
 Volume in drive Z is mount_tag
 Volume Serial Number is 0000-0000

 Directory of Z:\

12/31/1969  05:00 PM    <DIR>          .
12/31/1969  05:00 PM    <DIR>          ..
04/22/2022  04:38 AM                 8 hello.txt
               1 File(s)              8 bytes
               2 Dir(s)  97,393,795,072 bytes free