Author: royger
Date: Tue May 22 08:51:16 2018
New Revision: 334027
URL: https://svnweb.freebsd.org/changeset/base/334027
Log:
xen-blkback: do not use state 3 (XenbusStateInitialised)
Linux will not connect to a backend that's in state 3
(XenbusStateInitialised), it needs to be in state 2
(XenbusStateInitWait) for Linux to attempt to connect to the backend.
The protocol seems to suggest that the backend should indeed wait in
state 2 for the frontend to connect, which makes state 3 unusable for
disk backends.
Also make sure blkback will connect to the frontend if the frontend
reaches state 3 (XenbusStateInitialised) before blkback has processed
the results from the hotplug script (Submitted by Nathan Friess).
MFC after: 1 week
Modified:
head/sys/dev/xen/blkback/blkback.c
Modified: head/sys/dev/xen/blkback/blkback.c
==============================================================================
--- head/sys/dev/xen/blkback/blkback.c Tue May 22 08:27:33 2018
(r334026)
+++ head/sys/dev/xen/blkback/blkback.c Tue May 22 08:51:16 2018
(r334027)
@@ -806,6 +806,9 @@ struct xbb_softc {
/** Watch to wait for hotplug script execution */
struct xs_watch hotplug_watch;
+
+ /** Got the needed data from hotplug scripts? */
+ bool hotplug_done;
};
/*---------------------------- Request Processing
----------------------------*/
@@ -3310,12 +3313,11 @@ xbb_connect(struct xbb_softc *xbb)
{
int error;
- if (xenbus_get_state(xbb->dev) != XenbusStateInitialised)
+ if (!xbb->hotplug_done ||
+ (xenbus_get_state(xbb->dev) != XenbusStateInitWait) ||
+ (xbb_collect_frontend_info(xbb) != 0))
return;
- if (xbb_collect_frontend_info(xbb) != 0)
- return;
-
xbb->flags &= ~XBBF_SHUTDOWN;
/*
@@ -3412,6 +3414,7 @@ xbb_shutdown(struct xbb_softc *xbb)
free(xbb->hotplug_watch.node, M_XENBLOCKBACK);
xbb->hotplug_watch.node = NULL;
}
+ xbb->hotplug_done = false;
if (xenbus_get_state(xbb->dev) < XenbusStateClosing)
xenbus_set_state(xbb->dev, XenbusStateClosing);
@@ -3692,8 +3695,11 @@ xbb_attach_disk(struct xs_watch *watch, const char **v
return;
}
- /* Tell the front end that we are ready to connect. */
- xenbus_set_state(dev, XenbusStateInitialised);
+ xbb->hotplug_done = true;
+
+ /* The front end might be waiting for the backend, attach if so. */
+ if (xenbus_get_otherend_state(xbb->dev) == XenbusStateInitialised)
+ xbb_connect(xbb);
}
/**
@@ -3757,6 +3763,7 @@ xbb_attach(device_t dev)
* We need to wait for hotplug script execution before
* moving forward.
*/
+ KASSERT(!xbb->hotplug_done, ("Hotplug scripts already executed"));
watch_path = xs_join(xenbus_get_node(xbb->dev), "physical-device-path");
xbb->hotplug_watch.callback_data = (uintptr_t)dev;
xbb->hotplug_watch.callback = xbb_attach_disk;
_______________________________________________
svn-src-head@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
