From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Date: Mon, 27 Jan 2020 19:01:42 +0000

Subject: [PATCH] virtiofsd: Kill threads when queues are stopped

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Kill the threads we've started when the queues get stopped.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

With improvements by:

Signed-off-by: Eryu Guan <eguan@linux.alibaba.com>

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

(cherry picked from commit 10477ac47fc57d00a84802ff97c15450cd8021c1)

---

 tools/virtiofsd/fuse_virtio.c | 51 ++++++++++++++++++++++++++++++-----

 1 file changed, 44 insertions(+), 7 deletions(-)

diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c

index 872968f2c8..7a8774a3ee 100644

--- a/tools/virtiofsd/fuse_virtio.c

+++ b/tools/virtiofsd/fuse_virtio.c

@@ -41,6 +41,7 @@ struct fv_QueueInfo {

     /* Our queue index, corresponds to array position */

     int qidx;

     int kick_fd;

+    int kill_fd; /* For killing the thread */

     /* The element for the command currently being processed */

     VuVirtqElement *qe;

@@ -412,14 +413,17 @@ static void *fv_queue_thread(void *opaque)

     fuse_log(FUSE_LOG_INFO, "%s: Start for queue %d kick_fd %d\n", __func__,

              qi->qidx, qi->kick_fd);

     while (1) {

-        struct pollfd pf[1];

+        struct pollfd pf[2];

         pf[0].fd = qi->kick_fd;

         pf[0].events = POLLIN;

         pf[0].revents = 0;

+        pf[1].fd = qi->kill_fd;

+        pf[1].events = POLLIN;

+        pf[1].revents = 0;

         fuse_log(FUSE_LOG_DEBUG, "%s: Waiting for Queue %d event\n", __func__,

                  qi->qidx);

-        int poll_res = ppoll(pf, 1, NULL, NULL);

+        int poll_res = ppoll(pf, 2, NULL, NULL);

         if (poll_res == -1) {

             if (errno == EINTR) {

@@ -430,12 +434,23 @@ static void *fv_queue_thread(void *opaque)

             fuse_log(FUSE_LOG_ERR, "fv_queue_thread ppoll: %m\n");

             break;

         }

-        assert(poll_res == 1);

+        assert(poll_res >= 1);

         if (pf[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {

             fuse_log(FUSE_LOG_ERR, "%s: Unexpected poll revents %x Queue %d\n",

                      __func__, pf[0].revents, qi->qidx);

             break;

         }

+        if (pf[1].revents & (POLLERR | POLLHUP | POLLNVAL)) {

+            fuse_log(FUSE_LOG_ERR,

+                     "%s: Unexpected poll revents %x Queue %d killfd\n",

+                     __func__, pf[1].revents, qi->qidx);

+            break;

+        }

+        if (pf[1].revents) {

+            fuse_log(FUSE_LOG_INFO, "%s: kill event on queue %d - quitting\n",

+                     __func__, qi->qidx);

+            break;

+        }

         assert(pf[0].revents & POLLIN);

         fuse_log(FUSE_LOG_DEBUG, "%s: Got queue event on Queue %d\n", __func__,

                  qi->qidx);

@@ -589,6 +604,28 @@ out:

     return NULL;

 }

+static void fv_queue_cleanup_thread(struct fv_VuDev *vud, int qidx)

+{

+    int ret;

+    struct fv_QueueInfo *ourqi;

+

+    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);

+    }

+    close(ourqi->kill_fd);

+    ourqi->kick_fd = -1;

+}

+

 /* Callback from libvhost-user on start or stop of a queue */

 static void fv_queue_set_started(VuDev *dev, int qidx, bool started)

 {

@@ -633,16 +670,16 @@ static void fv_queue_set_started(VuDev *dev, int qidx, bool started)

         }

         ourqi = vud->qi[qidx];

         ourqi->kick_fd = dev->vq[qidx].kick_fd;

+

+        ourqi->kill_fd = eventfd(0, EFD_CLOEXEC | EFD_SEMAPHORE);

+        assert(ourqi->kill_fd != -1);

         if (pthread_create(&ourqi->thread, NULL, fv_queue_thread, ourqi)) {

             fuse_log(FUSE_LOG_ERR, "%s: Failed to create thread for queue %d\n",

                      __func__, qidx);

             assert(0);

         }

     } else {

-        /* TODO: Kill the thread */

-        assert(qidx < vud->nqueues);

-        ourqi = vud->qi[qidx];

-        ourqi->kick_fd = -1;

+        fv_queue_cleanup_thread(vud, qidx);

     }

 }