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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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Date: Mon, 27 Jan 2020 19:00:58 +0000
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Subject: [PATCH] virtiofsd: Add main virtio loop
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Processes incoming requests on the vhost-user fd.
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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(cherry picked from commit 204d8ae57b3c57098642c79b3c03d42495149c09)
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---
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 tools/virtiofsd/fuse_virtio.c | 42 ++++++++++++++++++++++++++++++++---
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 1 file changed, 39 insertions(+), 3 deletions(-)
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diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
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index 2ae3c764dd..1928a2025c 100644
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--- a/tools/virtiofsd/fuse_virtio.c
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+++ b/tools/virtiofsd/fuse_virtio.c
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@@ -11,12 +11,14 @@
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  * See the file COPYING.LIB
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  */
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+#include "fuse_virtio.h"
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 #include "fuse_i.h"
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 #include "standard-headers/linux/fuse.h"
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 #include "fuse_misc.h"
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 #include "fuse_opt.h"
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-#include "fuse_virtio.h"
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+#include <assert.h>
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+#include <errno.h>
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 #include <stdint.h>
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 #include <stdio.h>
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 #include <stdlib.h>
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@@ -80,15 +82,49 @@ static const VuDevIface fv_iface = {
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     .queue_is_processed_in_order = fv_queue_order,
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 };
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+/*
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+ * Main loop; this mostly deals with events on the vhost-user
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+ * socket itself, and not actual fuse data.
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+ */
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 int virtio_loop(struct fuse_session *se)
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 {
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     fuse_log(FUSE_LOG_INFO, "%s: Entry\n", __func__);
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-    while (1) {
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-        /* TODO: Add stuffing */
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+    while (!fuse_session_exited(se)) {
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+        struct pollfd pf[1];
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+        pf[0].fd = se->vu_socketfd;
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+        pf[0].events = POLLIN;
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+        pf[0].revents = 0;
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+
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+        fuse_log(FUSE_LOG_DEBUG, "%s: Waiting for VU event\n", __func__);
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+        int poll_res = ppoll(pf, 1, NULL, NULL);
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+
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+        if (poll_res == -1) {
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+            if (errno == EINTR) {
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+                fuse_log(FUSE_LOG_INFO, "%s: ppoll interrupted, going around\n",
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+                         __func__);
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+                continue;
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+            }
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+            fuse_log(FUSE_LOG_ERR, "virtio_loop ppoll: %m\n");
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+            break;
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+        }
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+        assert(poll_res == 1);
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+        if (pf[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
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+            fuse_log(FUSE_LOG_ERR, "%s: Unexpected poll revents %x\n", __func__,
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+                     pf[0].revents);
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+            break;
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+        }
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+        assert(pf[0].revents & POLLIN);
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+        fuse_log(FUSE_LOG_DEBUG, "%s: Got VU event\n", __func__);
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+        if (!vu_dispatch(&se->virtio_dev->dev)) {
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+            fuse_log(FUSE_LOG_ERR, "%s: vu_dispatch failed\n", __func__);
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+            break;
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+        }
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     }
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     fuse_log(FUSE_LOG_INFO, "%s: Exit\n", __func__);
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+
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+    return 0;
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 }
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 int virtio_session_mount(struct fuse_session *se)