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authorKevin Wolf <kwolf@redhat.com>2021-06-09 08:46:58 -0700
committerKevin Wolf <kwolf@redhat.com>2021-06-30 13:21:22 +0200
commita527e312b59ac382cb84af4b91f517a846f50705 (patch)
tree7cef671d37a79405677c7cba676a509e23291a09 /hw/block
parent415fc2940b1536061c904bf192e097c27d3a787b (diff)
downloadqemu-a527e312b59ac382cb84af4b91f517a846f50705.zip
qemu-a527e312b59ac382cb84af4b91f517a846f50705.tar.gz
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vhost-user-blk: Implement reconnection during realize
Commit dabefdd6 removed code that was supposed to try reconnecting during .realize(), but actually just crashed and had several design problems. This adds the feature back without the crash in simple cases while also fixing some design problems: Reconnection is now only tried if there was a problem with the connection and not an error related to the content (which would fail again the same way in the next attempt). Reconnection is limited to three attempts (four with the initial attempt) so that we won't end up in an infinite loop if a problem is permanent. If the backend restarts three times in the very short time window of device initialisation, we have bigger problems and erroring out is the right course of action. In the case that a connection error occurs and we reconnect, the error message is printed using error_report_err(), but otherwise ignored. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210609154658.350308-8-kwolf@redhat.com> Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'hw/block')
-rw-r--r--hw/block/vhost-user-blk.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index e49d2e4..ba13cb8 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -31,6 +31,8 @@
#include "sysemu/sysemu.h"
#include "sysemu/runstate.h"
+#define REALIZE_CONNECTION_RETRIES 3
+
static const int user_feature_bits[] = {
VIRTIO_BLK_F_SIZE_MAX,
VIRTIO_BLK_F_SEG_MAX,
@@ -455,8 +457,10 @@ static int vhost_user_blk_realize_connect(VHostUserBlk *s, Error **errp)
static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
{
+ ERRP_GUARD();
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBlk *s = VHOST_USER_BLK(vdev);
+ int retries;
int i, ret;
if (!s->chardev.chr) {
@@ -498,7 +502,17 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
s->inflight = g_new0(struct vhost_inflight, 1);
s->vhost_vqs = g_new0(struct vhost_virtqueue, s->num_queues);
- ret = vhost_user_blk_realize_connect(s, errp);
+ retries = REALIZE_CONNECTION_RETRIES;
+ assert(!*errp);
+ do {
+ if (*errp) {
+ error_prepend(errp, "Reconnecting after error: ");
+ error_report_err(*errp);
+ *errp = NULL;
+ }
+ ret = vhost_user_blk_realize_connect(s, errp);
+ } while (ret == -EPROTO && retries--);
+
if (ret < 0) {
goto virtio_err;
}