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

[Laurențiu Leahu-Vlăducu]

I tested this series on a test cluster and can say the following:

1. Patch 4/11 needs a rebase due to a recent change in 
src/PVE/QemuMigrate/Helpers.pm - but it is trivial to fix.

2. Setting virtiofs to read-only worked as intended.

3. Live migrations on CephFS with find-paths worked without issues (also 
when migrating multiple times). Live migrations with file-handles 
didn't, though, as reported by Filip as well - dd fails with an 
input/output error.


-> The source PVE node contains the following in the journal:

> Dec 02 17:39:19 node1 virtiofsd[109548]: node1 virtiofsd[109546]: Inode 2 ([unknown inode type; mount_id=0 device_id=0 inode_id=0]): Inode is invalid because of an error during the preceding migration, which was: Migration source has lost inode 2
> Dec 02 17:39:22 node1 pve-ha-lrm[112204]: Task 'UPID:node1:0001B64E:0015F115:692F1635:qmigrate:101:root at pam:' still active, waiting
> Dec 02 17:39:23 node1 virtiofsd[109548]: node1 virtiofsd[109546]: Failed to serialize inode 2 (st_dev=0, mnt_id=0, st_ino=0): Failed to reconstruct inode location; marking as invalid



-> The destination PVE node contains the following in the journal:

> Dec 02 17:39:23 node2 virtiofsd[76201]: node2 virtiofsd[76198]: Invalid inode 24 indexed: Opening file handle: Operation not permitted (os error 1)
> Dec 02 17:39:23 node2 virtiofsd[76201]: node2 virtiofsd[76198]: Invalid inode 22 indexed: Opening file handle: Operation not permitted (os error 1)
> Dec 02 17:39:23 node2 virtiofsd[76201]: node2 virtiofsd[76198]: Invalid inode 2 indexed: Migration source has lost inode 2
> Dec 02 17:39:23 node2 virtiofsd[76201]: node2 virtiofsd[76198]: Invalid handle 19 is open in guest: Opening inode 22 as handle 19: Inode is invalid because of an error during the preceding migration, which was: Opening file handle: Operation not permitted (os error 1)
> Dec 02 17:39:23 node2 virtiofsd[76201]: node2 virtiofsd[76198]: Invalid handle 20 is open in guest: Opening inode 24 as handle 20: Inode is invalid because of an error during the preceding migration, which was: Opening file handle: Operation not permitted (os error 1)


The following issue [0] sounds like it could be related.


4. Changing between find-paths and file-handles only works after a 
migration, which is weird (at first, it looks like file-handles works, 
but it always fails after the second attempt).

5. Just as a general remark, even if we say that these features are 
experimental, they should never cause data loss (aside of bugs, of 
course - but otherwise not). In case these options can cause data loss 
or inconsistencies, we should either only allow read-only access, or 
otherwise show a serious warning that combining these options might 
cause data loss (but then again, if it always fails, it's probably 
easier to not allow it - this is much better than causing data loss).


Everything else worked as intended during my tests.


[0] https://gitlab.com/virtio-fs/virtiofsd/-/issues/188


On 20.10.25 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
> 
> 
> pve-guest-common:
> 
> Markus Frank (1):
>    mapping: dir: add 'live-migration-method' parameter
> 
>   src/PVE/Mapping/Dir.pm | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> 
> 
> qemu-server:
> 
> Markus Frank (3):
>    fix #6370: virtiofs: add support for thread-pool-size option
>    virtiofs: add readonly option
>    virtiofs: add live migration support
> 
>   src/PVE/QemuMigrate/Helpers.pm | 14 +++++++++++---
>   src/PVE/QemuServer/Virtiofs.pm | 34 ++++++++++++++++++++++++++++++++++
>   2 files changed, 45 insertions(+), 3 deletions(-)
> 
> 
> 
> pve-docs:
> 
> Markus Frank (4):
>    virtiofs: add explanation for cache=metadata behavior
>    virtiofs: add table for optional parameters
>    virtiofs: add thread-pool-size description
>    virtiofs: add documentation for live migration
> 
>   qm.adoc | 50 ++++++++++++++++++++++++++++++++++++++++++--------
>   1 file changed, 42 insertions(+), 8 deletions(-)
> 
> 
> 
> pve-manager:
> 
> Markus Frank (3):
>    fix #6370: ui: virtiofs edit: add support for thread-pool-size option
>    virtiofs edit: add readonly checkbox
>    directory mapping: add live-migration-method option for virtiofs
> 
>   www/manager6/dc/DirMapView.js     |  8 ++++++++
>   www/manager6/qemu/VirtiofsEdit.js | 15 +++++++++++++++
>   www/manager6/window/DirMapEdit.js | 23 +++++++++++++++++++++++
>   3 files changed, 46 insertions(+)
>