Re: [Virtio-fs] Achieving parallelism in virtiofsd

[piaojun <piaojun@huawei.com>]

On 2019/7/5 16:04, Stefan Hajnoczi wrote:
> On Fri, Jul 05, 2019 at 12:43:16PM +0800, piaojun wrote:
>> From your description, virtiofsd does the same work as SPDK, and I
>> wonder if we could adapt it to SPDK-vhost-fs which is widely used.
> 
> I don't see 9P code in spdk.git/master.  How does the guest access
> SPDK's vhost-fs device and where is the code?

Yes, 9P code is not in spdk yet, and they can comunicate though share
memory. But it needs some extra work.

> 
> A quick look at blobfs suggests additional work is needed to introduce
> the concept of inodes instead of performing path name traversal on most
> operations.  This also changes the semantics of the file system since
> POSIX files can still be accessed after they are unlinked or renamed.
> 
> In theory SPDK can implement the vhost-user-fs device interface and
> replace virtiofsd but SPDK needs a POSIX file system implementation
> first.

Right, SPDK could only support blobfs now, and I wish it supporting any
local file system as backend in the future. SPDK vhost-fs patches is in
developing as below:

https://review.gerrithub.io/c/spdk/spdk/+/449163/5
https://review.gerrithub.io/c/spdk/spdk/+/449162/5

Thanks,
Jun

> 
> Stefan
>