Re: [Qemu-devel] virtfs/9p duplicate inodes

[Greg Kurz]

On Sat, 30 Mar 2019 14:48:02 +0100
Christian Schoenebeck via Qemu-devel <address@hidden> wrote:

> Hi list,
> 
> currently the 9p implementation in qemu causes inode number collisions on 
> guest OS level if the directory exported by 9p consists on host level of more 
> than one file system being mounted inside that exported directory tree; which 
> leads to severe misbehaviours on guest side with all kinds of applications.
> 
> The problem here is that when stat-ing a file/dir on guest side, 9p always 
> returns the same device id for every file/dir of the exported directory (the 
> virtual 9p device itself), while at the same time it simply provides to the 
> guest the inode number of the requested file/dir from host side (+2).
> 
> Since the combination of (device-id, inode-nr) must be unique per file on any 
> system, this needs to be fixed. Any suggestions?
> 

Hi,

Maybe have a look at this tentative to fix QID collisions:

https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg02283.html

Cc'ing original submitter.

Cheers,

--
Greg

> As far as I can see it, either a) different device IDs should be returned to 
> the guest for actually different file systems on host level, or b) 9p should 
> remap the inode numbers appropriately such that the inode number range on 
> guest side would always be isolated between the individual file systems 
> accessed on host side.
> 
> Best regards,
> Christian Schoenebeck
>