[pve-devel] [PATCH guest-common/qemu-server/docs/manager v1 0/11] Virtiofs improvements

[Filip Schauer]

On 20/10/2025 14:18, Markus Frank wrote:
> This patch series superseeds the patch series
> "virtiofs: add thread-pool-size and improve docs" and adds support for
> the read-only flag and live-migration.
>
> Virtiofsd migration documentation:
> https://gitlab.com/virtio-fs/virtiofsd/-/blob/main/doc/migration.md
>
> build-order:
> 1. pve-guest-common
> 2. qemu-server
> 3. pve-docs
> 4. pve-manager

Tested read-only: Works as expected.

Tested live migration with both find-paths and file-handles while
reading a small file:
1. Opened file on first node
2. Read a few bytes from the open file handle
3. Migrated the VM to the second node
4. Read some more bytes from the open file handle
This worked fine.

Tested live migration while copying a 1GiB file within the virtiofs:
1. Mounted a CIFS share on all nodes and configured the directory
    mappings with `file-handles` as the live migration method
2. Created a 1GiB file: `dd if=/dev/urandom of=testA bs=4M count=256`
3. Started a copy inside the VM:
    `/mnt/virtiofs# dd if=testA of=testB status=progress`
4. Started a live migration
5. Immediately after migration dd failed with:
    ```
    dd: error reading 'testA': Input/output error
    dd: closing input file 'testA': Input/output error
    ```
    I tried the same with Live Migration Method set to `find-paths`.
    This also failed upon migration. This time with:
    ```
    dd: writing to 'testB': Input/output error
    dd: closing input file 'testA': Input/output error
    ```

Another thing I noticed: The pveDirMapSelector in the VirtiofsInputPanel
does not show whether a directory mapping is configured for the node.
Meanwhile the pvePCIMapSelector and pveUSBMapSelector show either
"No mapping for node..." or "Mapping matches host data". Might be nice
to have that for Virtiofs too.

PS: Please run `make tidy`