Re: [PATCH 00/18] virtiofs: Fix various races and cleanups round 1

From: "Michael S. Tsirkin" <mst@redhat.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: linux-fsdevel@vger.kernel.org,
	virtualization@lists.linux-foundation.org, miklos@szeredi.hu,
	linux-kernel@vger.kernel.org, virtio-fs@redhat.com,
	stefanha@redhat.com, dgilbert@redhat.com
Subject: Re: [PATCH 00/18] virtiofs: Fix various races and cleanups round 1
Date: Fri, 6 Sep 2019 09:37:26 -0400	[thread overview]
Message-ID: <20190906093703-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20190905194859.16219-1-vgoyal@redhat.com>

On Thu, Sep 05, 2019 at 03:48:41PM -0400, Vivek Goyal wrote:
> Hi,
> 
> Michael Tsirkin pointed out issues w.r.t various locking related TODO
> items and races w.r.t device removal. 
> 
> In this first round of cleanups, I have taken care of most pressing
> issues.
> 
> These patches apply on top of following.
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse.git#virtiofs-v4
> 
> I have tested these patches with mount/umount and device removal using
> qemu monitor. For example.
> 
> virsh qemu-monitor-command --hmp vm9-f28 device_del myvirtiofs
> 
> Now a mounted device can be removed and file system will return errors
> -ENOTCONN and one can unmount it.
> 
> Miklos, if you are fine with the patches, I am fine if you fold these
> all into existing patch. I kept them separate so that review is easier.
> 
> Any feedback or comments are welcome.
> 
> Thanks
> Vivek
> 


Another version of a patch with fixes all rolled in would also
be nice.
> Vivek Goyal (18):
>   virtiofs: Remove request from processing list before calling end
>   virtiofs: Check whether hiprio queue is connected at submission time
>   virtiofs: Pass fsvq instead of vq as parameter to
>     virtio_fs_enqueue_req
>   virtiofs: Check connected state for VQ_REQUEST queue as well
>   Maintain count of in flight requests for VQ_REQUEST queue
>   virtiofs: ->remove should not clean virtiofs fuse devices
>   virtiofs: Stop virtiofs queues when device is being removed
>   virtiofs: Drain all pending requests during ->remove time
>   virtiofs: Add an helper to start all the queues
>   virtiofs: Do not use device managed mem for virtio_fs and virtio_fs_vq
>   virtiofs: stop and drain queues after sending DESTROY
>   virtiofs: Use virtio_fs_free_devs() in error path
>   virtiofs: Do not access virtqueue in request submission path
>   virtiofs: Add a fuse_iqueue operation to put() reference
>   virtiofs: Make virtio_fs object refcounted
>   virtiofs: Use virtio_fs_mutex for races w.r.t ->remove and mount path
>   virtiofs: Remove TODO to quiesce/end_requests
>   virtiofs: Remove TODO item from virtio_fs_free_devs()
> 
>  fs/fuse/fuse_i.h    |   5 +
>  fs/fuse/inode.c     |   6 +
>  fs/fuse/virtio_fs.c | 259 ++++++++++++++++++++++++++++++++------------
>  3 files changed, 198 insertions(+), 72 deletions(-)
> 
> -- 
> 2.20.1