similar to: [PATCH 0/3] virtiofs: Small Cleanups for 5.5

Hi, We have couple of places which can result in deadlock. This patch series fixes these. We can be called with fc->bg_lock (for background requests) while submitting a request. This leads to two constraints. - We can't end requests in submitter's context and call fuse_end_request() as it tries to take fc->bg_lock as well. So queue these requests on a list and use a worker to

When the Virtio queue is full, a work item is scheduled to execute in 1ms that retries adding the request to the queue. This is a large amount of time on the scale on which a virtio-fs device can operate. When using a DPU this is around 40us baseline without going to a remote server (4k, QD=1). This patch queues requests when the Virtio queue is full, and when a completed request is taken off,

When the Virtio queue is full, a work item is scheduled to execute in 1ms that retries adding the request to the queue. This is a large amount of time on the scale on which a virtio-fs device can operate. When using a DPU this is around 40us baseline without going to a remote server (4k, QD=1). This patch queues requests when the Virtio queue is full, and when a completed request is taken off,

On Tue, Sep 03, 2019 at 01:42:02PM +0200, Miklos Szeredi wrote: > From: Stefan Hajnoczi <stefanha at redhat.com> > > Add a basic file system module for virtio-fs. This does not yet contain > shared data support between host and guest or metadata coherency speedups. > However it is already significantly faster than virtio-9p. > > Design Overview > ===============

On Tue, Sep 03, 2019 at 01:42:02PM +0200, Miklos Szeredi wrote: > From: Stefan Hajnoczi <stefanha at redhat.com> > > Add a basic file system module for virtio-fs. This does not yet contain > shared data support between host and guest or metadata coherency speedups. > However it is already significantly faster than virtio-9p. > > Design Overview > ===============

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

On Wed, May 31, 2023 at 04:49:39PM -0400, Vivek Goyal wrote: > On Wed, May 31, 2023 at 10:34:15PM +0200, Peter-Jan Gootzen wrote: > > On 31/05/2023 21:18, Vivek Goyal wrote: > > > On Wed, May 31, 2023 at 07:10:32PM +0200, Peter-Jan Gootzen wrote: > > >> When the Virtio queue is full, a work item is scheduled > > >> to execute in 1ms that retries adding the

On Thu, Sep 05, 2019 at 03:15:15PM -0400, Vivek Goyal wrote: > On Tue, Sep 03, 2019 at 09:55:49AM -0400, Michael S. Tsirkin wrote: > [..] > > What's with all of the TODOs? Some of these are really scary, > > looks like they need to be figured out before this is merged. > > Hi Michael, > > One of the issue I noticed is races w.r.t device removal and super >

On Wed, May 31, 2023 at 10:34:15PM +0200, Peter-Jan Gootzen wrote: > On 31/05/2023 21:18, Vivek Goyal wrote: > > On Wed, May 31, 2023 at 07:10:32PM +0200, Peter-Jan Gootzen wrote: > >> When the Virtio queue is full, a work item is scheduled > >> to execute in 1ms that retries adding the request to the queue. > >> This is a large amount of time on the scale on

On 01/06/2023 16:08, Stefan Hajnoczi wrote: > On Wed, May 31, 2023 at 04:49:39PM -0400, Vivek Goyal wrote: >> On Wed, May 31, 2023 at 10:34:15PM +0200, Peter-Jan Gootzen wrote: >>> On 31/05/2023 21:18, Vivek Goyal wrote: >>>> On Wed, May 31, 2023 at 07:10:32PM +0200, Peter-Jan Gootzen wrote: >>>>> When the Virtio queue is full, a work item is scheduled

On Thu, Sep 05, 2019 at 03:48:56PM -0400, Vivek Goyal wrote: > This object is used both by fuse_connection as well virt device. So make > this object reference counted and that makes it easy to define life cycle > of the object. > > Now deivce can be removed while filesystem is still mounted. This will > cleanup all the virtqueues but virtio_fs object will still be around and

On Thu, Sep 05, 2019 at 03:48:56PM -0400, Vivek Goyal wrote: > This object is used both by fuse_connection as well virt device. So make > this object reference counted and that makes it easy to define life cycle > of the object. > > Now deivce can be removed while filesystem is still mounted. This will > cleanup all the virtqueues but virtio_fs object will still be around and

On Thu, Sep 05, 2019 at 03:48:57PM -0400, Vivek Goyal wrote: > It is possible that a mount is in progress and device is being removed at > the same time. Use virtio_fs_mutex to avoid races. > > This also takes care of bunch of races and removes some TODO items. > > Signed-off-by: Vivek Goyal <vgoyal at redhat.com> > --- > fs/fuse/virtio_fs.c | 32

On Thu, Sep 05, 2019 at 03:48:57PM -0400, Vivek Goyal wrote: > It is possible that a mount is in progress and device is being removed at > the same time. Use virtio_fs_mutex to avoid races. > > This also takes care of bunch of races and removes some TODO items. > > Signed-off-by: Vivek Goyal <vgoyal at redhat.com> > --- > fs/fuse/virtio_fs.c | 32

When the Virtio queue is full, a work item is scheduled to execute in 1ms that retries adding the request to the queue. This is a large amount of time on the scale on which a virtio-fs device can operate. When using a DPU this is around 40us baseline without going to a remote server (4k, QD=1). This patch queues requests when the Virtio queue is full, and when a completed request is taken off,

We are sending whole of virtio_fs_foreget struct to the other end over virtqueue. Other end does not need to see elements like "struct list". That's internal detail of guest kernel. Fix it. Signed-off-by: Vivek Goyal <vgoyal at redhat.com> --- fs/fuse/virtio_fs.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/fs/fuse/virtio_fs.c

On Thu, Sep 05, 2019 at 03:48:49PM -0400, Vivek Goyal wrote: > +static void virtio_fs_drain_queue(struct virtio_fs_vq *fsvq) > +{ > + WARN_ON(fsvq->in_flight < 0); > + > + /* Wait for in flight requests to finish.*/ > + while (1) { > + spin_lock(&fsvq->lock); > + if (!fsvq->in_flight) { > + spin_unlock(&fsvq->lock); > + break; > + }

On Thu, Sep 05, 2019 at 03:48:49PM -0400, Vivek Goyal wrote: > +static void virtio_fs_drain_queue(struct virtio_fs_vq *fsvq) > +{ > + WARN_ON(fsvq->in_flight < 0); > + > + /* Wait for in flight requests to finish.*/ > + while (1) { > + spin_lock(&fsvq->lock); > + if (!fsvq->in_flight) { > + spin_unlock(&fsvq->lock); > + break; > + }

On Fri, Sep 06, 2019 at 10:17:05AM -0400, Vivek Goyal wrote: > On Fri, Sep 06, 2019 at 11:52:10AM +0100, Stefan Hajnoczi wrote: > > On Thu, Sep 05, 2019 at 03:48:49PM -0400, Vivek Goyal wrote: > > > +static void virtio_fs_drain_queue(struct virtio_fs_vq *fsvq) > > > +{ > > > + WARN_ON(fsvq->in_flight < 0); > > > + > > > + /* Wait for in

While we wait for queue to finish draining, use completions instead of uslee_range(). This is better way of waiting for event. Signed-off-by: Vivek Goyal <vgoyal at redhat.com> --- fs/fuse/virtio_fs.c | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-) diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index 43224db8d9ed..b5ba83ef1914 100644