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authorGreg Kurz <groug@kaod.org>2016-10-17 14:13:58 +0200
committerGreg Kurz <groug@kaod.org>2016-10-17 14:13:58 +0200
commit0e44a0fd3f28cccb8963fdfc05c53c546b3f46b6 (patch)
tree5bb0d01ef8e09b1b31d751c50e0f2a8e736049c5 /hw
parentf74e27bf0f07425aba6cb812aa7f5aa98bb68542 (diff)
virtio-9p: add reset handler
Virtio devices should implement the VirtIODevice->reset() function to perform necessary cleanup actions and to bring the device to a quiescent state. In the case of the virtio-9p device, this means: - emptying the list of active PDUs (i.e. draining all in-flight I/O) - freeing all fids (i.e. close open file descriptors and free memory) That's what this patch does. The reset handler first waits for all active PDUs to complete. Since completion happens in the QEMU global aio context, we just have to loop around aio_poll() until the active list is empty. The freeing part involves some actions to be performed on the backend, like closing file descriptors or flushing extended attributes to the underlying filesystem. The virtfs_reset() function already does the job: it calls free_fid() for all open fids not involved in an ongoing I/O operation. We are sure this is the case since we have drained the PDU active list. The current code implements all backend accesses with coroutines, but we want to stay synchronous on the reset path. We can either change the current code to be able to run when not in coroutine context, or create a coroutine context and wait for virtfs_reset() to complete. This patch goes for the latter because it results in simpler code. Note that we also need to create a dummy PDU because it is also an API to pass the FsContext pointer to all backend callbacks. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/9pfs/9p.c30
-rw-r--r--hw/9pfs/9p.h1
-rw-r--r--hw/9pfs/virtio-9p-device.c8
3 files changed, 39 insertions, 0 deletions
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index f0dc2ce589..26aa7d5648 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -3522,6 +3522,36 @@ void v9fs_device_unrealize_common(V9fsState *s, Error **errp)
g_free(s->tag);
}
+typedef struct VirtfsCoResetData {
+ V9fsPDU pdu;
+ bool done;
+} VirtfsCoResetData;
+
+static void coroutine_fn virtfs_co_reset(void *opaque)
+{
+ VirtfsCoResetData *data = opaque;
+
+ virtfs_reset(&data->pdu);
+ data->done = true;
+}
+
+void v9fs_reset(V9fsState *s)
+{
+ VirtfsCoResetData data = { .pdu = { .s = s }, .done = false };
+ Coroutine *co;
+
+ while (!QLIST_EMPTY(&s->active_list)) {
+ aio_poll(qemu_get_aio_context(), true);
+ }
+
+ co = qemu_coroutine_create(virtfs_co_reset, &data);
+ qemu_coroutine_enter(co);
+
+ while (!data.done) {
+ aio_poll(qemu_get_aio_context(), true);
+ }
+}
+
static void __attribute__((__constructor__)) v9fs_set_fd_limit(void)
{
struct rlimit rlim;
diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
index c4df66d1c4..2523a445f8 100644
--- a/hw/9pfs/9p.h
+++ b/hw/9pfs/9p.h
@@ -339,5 +339,6 @@ ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...);
V9fsPDU *pdu_alloc(V9fsState *s);
void pdu_free(V9fsPDU *pdu);
void pdu_submit(V9fsPDU *pdu);
+void v9fs_reset(V9fsState *s);
#endif
diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
index e98dd0c4c0..1782e4a227 100644
--- a/hw/9pfs/virtio-9p-device.c
+++ b/hw/9pfs/virtio-9p-device.c
@@ -141,6 +141,13 @@ static void virtio_9p_device_unrealize(DeviceState *dev, Error **errp)
v9fs_device_unrealize_common(s, errp);
}
+static void virtio_9p_reset(VirtIODevice *vdev)
+{
+ V9fsVirtioState *v = (V9fsVirtioState *)vdev;
+
+ v9fs_reset(&v->state);
+}
+
ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
const char *fmt, va_list ap)
{
@@ -207,6 +214,7 @@ static void virtio_9p_class_init(ObjectClass *klass, void *data)
vdc->unrealize = virtio_9p_device_unrealize;
vdc->get_features = virtio_9p_get_features;
vdc->get_config = virtio_9p_get_config;
+ vdc->reset = virtio_9p_reset;
}
static const TypeInfo virtio_device_info = {