Re: [PATCH 0/2] virtio-fs: Add 'file' mount option

[Josef Bacik <josef@toxicpanda.com>]

On Tue, Jul 09, 2024 at 01:19:16PM +0200, Hanna Czenczek wrote:
> Hi,
> 
> We want to be able to mount filesystems that just consist of one regular
> file via virtio-fs, i.e. no root directory, just a file as the root
> node.
> 
> While that is possible via FUSE itself (through the 'rootmode' mount
> option, which is automatically set by the fusermount help program to
> match the mount point's inode mode), there is no virtio-fs option yet
> that would allow changing the rootmode from S_IFDIR to S_IFREG.
> 
> To do that, this series introduces a new 'file' mount option that does
> precisely that.  Alternatively, we could provide the same 'rootmode'
> option that FUSE has, but as laid out in patch 1's commit description,
> that option is a bit cumbersome for virtio-fs (in a way that it is not
> for FUSE), and its usefulness as a more general option is limited.
> 

All this does is make file an alias for something a little easier for users to
read, which can easily be done in libfuse.  Add the code to lib/mount.c to alias
'file' to turn it into rootmode=S_IFREG when it sends it to the kernel, it's not
necessary to do this in the kernel.  Thanks,

Josef