On Thu, Sep 30, 2021 at 11:30:32AM -0400, Vivek Goyal wrote: > Add a notification queue which will be used to send async notifications > for file lock availability. > > Signed-off-by: Vivek Goyal > Signed-off-by: Ioannis Angelakopoulos > --- > hw/virtio/vhost-user-fs-pci.c | 4 +- > hw/virtio/vhost-user-fs.c | 62 +++++++++++++++++++++++++-- > include/hw/virtio/vhost-user-fs.h | 2 + > tools/virtiofsd/fuse_i.h | 1 + > tools/virtiofsd/fuse_virtio.c | 70 +++++++++++++++++++++++-------- > 5 files changed, 116 insertions(+), 23 deletions(-) > > diff --git a/hw/virtio/vhost-user-fs-pci.c b/hw/virtio/vhost-user-fs-pci.c > index 2ed8492b3f..cdb9471088 100644 > --- a/hw/virtio/vhost-user-fs-pci.c > +++ b/hw/virtio/vhost-user-fs-pci.c > @@ -41,8 +41,8 @@ static void vhost_user_fs_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp) > DeviceState *vdev = DEVICE(&dev->vdev); > > if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) { > - /* Also reserve config change and hiprio queue vectors */ > - vpci_dev->nvectors = dev->vdev.conf.num_request_queues + 2; > + /* Also reserve config change, hiprio and notification queue vectors */ > + vpci_dev->nvectors = dev->vdev.conf.num_request_queues + 3; > } > > qdev_realize(vdev, BUS(&vpci_dev->bus), errp); > diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c > index d1efbc5b18..6bafcf0243 100644 > --- a/hw/virtio/vhost-user-fs.c > +++ b/hw/virtio/vhost-user-fs.c > @@ -31,6 +31,7 @@ static const int user_feature_bits[] = { > VIRTIO_F_NOTIFY_ON_EMPTY, > VIRTIO_F_RING_PACKED, > VIRTIO_F_IOMMU_PLATFORM, > + VIRTIO_FS_F_NOTIFICATION, > > VHOST_INVALID_FEATURE_BIT > }; > @@ -147,7 +148,7 @@ static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq) > */ > } > > -static void vuf_create_vqs(VirtIODevice *vdev) > +static void vuf_create_vqs(VirtIODevice *vdev, bool notification_vq) > { > VHostUserFS *fs = VHOST_USER_FS(vdev); > unsigned int i; > @@ -155,6 +156,15 @@ static void vuf_create_vqs(VirtIODevice *vdev) > /* Hiprio queue */ > fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, > vuf_handle_output); > + /* > + * Notification queue. Feature negotiation happens later. So at this > + * point of time we don't know if driver will use notification queue > + * or not. > + */ > + if (notification_vq) { > + fs->notification_vq = virtio_add_queue(vdev, fs->conf.queue_size, > + vuf_handle_output); > + } > > /* Request queues */ > fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues); > @@ -163,8 +173,12 @@ static void vuf_create_vqs(VirtIODevice *vdev) > vuf_handle_output); > } > > - /* 1 high prio queue, plus the number configured */ > - fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues; > + /* 1 high prio queue, 1 notification queue plus the number configured */ > + if (notification_vq) { > + fs->vhost_dev.nvqs = 2 + fs->conf.num_request_queues; > + } else { > + fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues; > + } > fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs); > } > > @@ -176,6 +190,11 @@ static void vuf_cleanup_vqs(VirtIODevice *vdev) > virtio_delete_queue(fs->hiprio_vq); > fs->hiprio_vq = NULL; > > + if (fs->notification_vq) { > + virtio_delete_queue(fs->notification_vq); > + } > + fs->notification_vq = NULL; > + > for (i = 0; i < fs->conf.num_request_queues; i++) { > virtio_delete_queue(fs->req_vqs[i]); > } > @@ -194,9 +213,43 @@ static uint64_t vuf_get_features(VirtIODevice *vdev, > { > VHostUserFS *fs = VHOST_USER_FS(vdev); > > + virtio_add_feature(&features, VIRTIO_FS_F_NOTIFICATION); > + > return vhost_get_features(&fs->vhost_dev, user_feature_bits, features); > } > > +static void vuf_set_features(VirtIODevice *vdev, uint64_t features) > +{ > + VHostUserFS *fs = VHOST_USER_FS(vdev); > + > + if (virtio_has_feature(features, VIRTIO_FS_F_NOTIFICATION)) { > + fs->notify_enabled = true; > + /* > + * If guest first booted with no notification queue support and > + * later rebooted with kernel which supports notification, we > + * can end up here > + */ > + if (!fs->notification_vq) { > + vuf_cleanup_vqs(vdev); > + vuf_create_vqs(vdev, true); > + } I would simplify things by unconditionally creating the notification vq for the device and letting the vhost-user device backend decide whether it wants to handle the vq or not. If the backend doesn't implement the vq then it also won't advertise VIRTIO_FS_F_NOTIFICATION so the guest driver won't submit virtqueue buffers. I'm not 100% sure if that approach works. It should be tested with a virtiofsd that doesn't implement the notification vq, for example. But I think it's worth exploring that because the code will be simpler than worrying about whether notifications are enabled or disabled. > + return; > + } > + > + fs->notify_enabled = false; > + if (!fs->notification_vq) { > + return; > + } > + /* > + * Driver does not support notification queue. Reconfigure queues > + * and do not create notification queue. > + */ > + vuf_cleanup_vqs(vdev); > + > + /* Create queues again */ > + vuf_create_vqs(vdev, false); > +} > + > static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx, > bool mask) > { > @@ -262,7 +315,7 @@ static void vuf_device_realize(DeviceState *dev, Error **errp) > virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS, > sizeof(struct virtio_fs_config)); > > - vuf_create_vqs(vdev); > + vuf_create_vqs(vdev, true); > ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user, > VHOST_BACKEND_TYPE_USER, 0, errp); > if (ret < 0) { > @@ -327,6 +380,7 @@ static void vuf_class_init(ObjectClass *klass, void *data) > vdc->realize = vuf_device_realize; > vdc->unrealize = vuf_device_unrealize; > vdc->get_features = vuf_get_features; > + vdc->set_features = vuf_set_features; > vdc->get_config = vuf_get_config; > vdc->set_status = vuf_set_status; > vdc->guest_notifier_mask = vuf_guest_notifier_mask; > diff --git a/include/hw/virtio/vhost-user-fs.h b/include/hw/virtio/vhost-user-fs.h > index 0d62834c25..95dc0dd402 100644 > --- a/include/hw/virtio/vhost-user-fs.h > +++ b/include/hw/virtio/vhost-user-fs.h > @@ -39,7 +39,9 @@ struct VHostUserFS { > VhostUserState vhost_user; > VirtQueue **req_vqs; > VirtQueue *hiprio_vq; > + VirtQueue *notification_vq; > int32_t bootindex; > + bool notify_enabled; > > /*< public >*/ > }; > diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h > index 492e002181..4942d080da 100644 > --- a/tools/virtiofsd/fuse_i.h > +++ b/tools/virtiofsd/fuse_i.h > @@ -73,6 +73,7 @@ struct fuse_session { > int vu_socketfd; > struct fv_VuDev *virtio_dev; > int thread_pool_size; > + bool notify_enabled; > }; > > struct fuse_chan { > diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c > index baead08b28..f5b87a508a 100644 > --- a/tools/virtiofsd/fuse_virtio.c > +++ b/tools/virtiofsd/fuse_virtio.c > @@ -14,6 +14,7 @@ > #include "qemu/osdep.h" > #include "qemu/iov.h" > #include "qapi/error.h" > +#include "standard-headers/linux/virtio_fs.h" > #include "fuse_i.h" > #include "standard-headers/linux/fuse.h" > #include "fuse_misc.h" > @@ -85,12 +86,25 @@ struct fv_VuDev { > /* Callback from libvhost-user */ > static uint64_t fv_get_features(VuDev *dev) > { > - return 1ULL << VIRTIO_F_VERSION_1; > + uint64_t features; > + > + features = 1ull << VIRTIO_F_VERSION_1 | > + 1ull << VIRTIO_FS_F_NOTIFICATION; > + > + return features; > } > > /* Callback from libvhost-user */ > static void fv_set_features(VuDev *dev, uint64_t features) > { > + struct fv_VuDev *vud = container_of(dev, struct fv_VuDev, dev); > + struct fuse_session *se = vud->se; > + > + if ((1ull << VIRTIO_FS_F_NOTIFICATION) & features) { > + se->notify_enabled = true; > + } else { > + se->notify_enabled = false; > + } > } > > /* > @@ -719,22 +733,25 @@ static void fv_queue_cleanup_thread(struct fv_VuDev *vud, int qidx) > { > int ret; > struct fv_QueueInfo *ourqi; > + struct fuse_session *se = vud->se; > > assert(qidx < vud->nqueues); > ourqi = vud->qi[qidx]; > > - /* Kill the thread */ > - if (eventfd_write(ourqi->kill_fd, 1)) { > - fuse_log(FUSE_LOG_ERR, "Eventfd_write for queue %d: %s\n", > - qidx, strerror(errno)); > - } > - ret = pthread_join(ourqi->thread, NULL); > - if (ret) { > - fuse_log(FUSE_LOG_ERR, "%s: Failed to join thread idx %d err %d\n", > - __func__, qidx, ret); > + /* qidx == 1 is the notification queue if notifications are enabled */ > + if (!se->notify_enabled || qidx != 1) { > + /* Kill the thread */ > + if (eventfd_write(ourqi->kill_fd, 1)) { > + fuse_log(FUSE_LOG_ERR, "Eventfd_read for queue: %m\n"); > + } > + ret = pthread_join(ourqi->thread, NULL); > + if (ret) { > + fuse_log(FUSE_LOG_ERR, "%s: Failed to join thread idx %d err" > + " %d\n", __func__, qidx, ret); > + } > + close(ourqi->kill_fd); > } > pthread_mutex_destroy(&ourqi->vq_lock); > - close(ourqi->kill_fd); > ourqi->kick_fd = -1; > g_free(vud->qi[qidx]); > vud->qi[qidx] = NULL; > @@ -757,6 +774,9 @@ static void fv_queue_set_started(VuDev *dev, int qidx, bool started) > { > struct fv_VuDev *vud = container_of(dev, struct fv_VuDev, dev); > struct fv_QueueInfo *ourqi; > + int valid_queues = 2; /* One hiprio queue and one request queue */ > + bool notification_q = false; > + struct fuse_session *se = vud->se; > > fuse_log(FUSE_LOG_INFO, "%s: qidx=%d started=%d\n", __func__, qidx, > started); > @@ -768,10 +788,19 @@ static void fv_queue_set_started(VuDev *dev, int qidx, bool started) > * well-behaved client in mind and may not protect against all types of > * races yet. > */ > - if (qidx > 1) { > - fuse_log(FUSE_LOG_ERR, > - "%s: multiple request queues not yet implemented, please only " > - "configure 1 request queue\n", > + if (se->notify_enabled) { > + valid_queues++; > + /* > + * If notification queue is enabled, then qidx 1 is notificaiton queue. s/notificaiton/notification/ > + */ > + if (qidx == 1) { > + notification_q = true; > + } > + } > + > + if (qidx >= valid_queues) { > + fuse_log(FUSE_LOG_ERR, "%s: multiple request queues not yet" > + "implemented, please only configure 1 request queue\n", > __func__); > exit(EXIT_FAILURE); > } > @@ -793,11 +822,18 @@ static void fv_queue_set_started(VuDev *dev, int qidx, bool started) > assert(vud->qi[qidx]->kick_fd == -1); > } > ourqi = vud->qi[qidx]; > + pthread_mutex_init(&ourqi->vq_lock, NULL); > + /* > + * For notification queue, we don't have to start a thread yet. > + */ > + if (notification_q) { > + return; > + } > + > ourqi->kick_fd = dev->vq[qidx].kick_fd; > > ourqi->kill_fd = eventfd(0, EFD_CLOEXEC | EFD_SEMAPHORE); > assert(ourqi->kill_fd != -1); > - pthread_mutex_init(&ourqi->vq_lock, NULL); > > if (pthread_create(&ourqi->thread, NULL, fv_queue_thread, ourqi)) { > fuse_log(FUSE_LOG_ERR, "%s: Failed to create thread for queue %d\n", > @@ -1048,7 +1084,7 @@ int virtio_session_mount(struct fuse_session *se) > se->vu_socketfd = data_sock; > se->virtio_dev->se = se; > pthread_rwlock_init(&se->virtio_dev->vu_dispatch_rwlock, NULL); > - if (!vu_init(&se->virtio_dev->dev, 2, se->vu_socketfd, fv_panic, NULL, > + if (!vu_init(&se->virtio_dev->dev, 3, se->vu_socketfd, fv_panic, NULL, The guest driver can invoke fv_queue_set_started() with qidx=2 even when VIRTIO_FS_F_NOTIFICATION is off. Luckily the following check protects fv_queue_set_started(): if (qidx >= valid_queues) { fuse_log(FUSE_LOG_ERR, "%s: multiple request queues not yet" "implemented, please only configure 1 request queue\n", __func__); exit(EXIT_FAILURE); } However, the error message suggests this is related to multiqueue. In fact, we'll need to keep this check even once multiqueue has been implemented. Maybe the error message should be tweaked or at least a comment needs to be added to the code so this check isn't accidentally removed once multiqueue is implemented.