# HG changeset patch
# User emellor@xxxxxxxxxxxxxxxxxxxxxx
# Node ID 5a728a884242b7aa2a0ab6d998adbc117b0ef917
# Parent 2c0b3b8077564205640952f8919e39ee05872cfd
Instead of writing errors to
/local/domain/0/backend/<devclass>/<dom>/<devid>/error, write them instead to
/local/domain/0/error/backend/<yada>. This is not the best place for them
perhaps, but it moves them out of the backend directory, on which the drivers
have a watch. This fixes the problem whereby writing an error will trigger a
watch, causing the error message to be written again, and repeat. Fixes bug
#286.
Signed-off-by: Ewan Mellor <ewan@xxxxxxxxxxxxx>
diff -r 2c0b3b807756 -r 5a728a884242
linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_xs.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_xs.c Sun Oct 23
15:54:51 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_xs.c Sun Oct 23
21:34:13 2005
@@ -516,17 +516,38 @@
}
EXPORT_SYMBOL(xenbus_printf);
+/**
+ * Return the path to the error node for the given device, or NULL on failure.
+ * If the value returned is non-NULL, then it is the caller's to kfree.
+ */
+static char *error_path(struct xenbus_device *dev)
+{
+ char *path_buffer = kmalloc(strlen("error/") + strlen(dev->nodename) +
+ 1, GFP_KERNEL);
+ if (path_buffer == NULL) {
+ return NULL;
+ }
+
+ strcpy(path_buffer, "error/");
+ strcpy(path_buffer + strlen("error/"), dev->nodename);
+
+ return path_buffer;
+}
+
/* Report a (negative) errno into the store, with explanation. */
void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...)
{
va_list ap;
int ret;
unsigned int len;
- char *printf_buffer;
+ char *printf_buffer = NULL, *path_buffer = NULL;
printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
- if (printf_buffer == NULL)
+ if (printf_buffer == NULL) {
+ printk("xenbus: failed to write error node for %s (%d): %d\n",
+ dev->nodename, err, errno);
goto fail;
+ }
len = sprintf(printf_buffer, "%i ", -err);
va_start(ap, fmt);
@@ -535,15 +556,26 @@
BUG_ON(len + ret > PRINTF_BUFFER_SIZE-1);
dev->has_error = 1;
- if (xenbus_write(NULL, dev->nodename, "error", printf_buffer) != 0)
+
+ path_buffer = error_path(dev);
+
+ if (path_buffer == NULL) {
+ printk("xenbus: failed to write error node for %s (%s): %d\n",
+ dev->nodename, printf_buffer, errno);
goto fail;
-
- kfree(printf_buffer);
- return;
-
- fail:
- printk("xenbus: failed to write error node for %s (%s)\n",
- dev->nodename, printf_buffer);
+ }
+
+ if (xenbus_write(NULL, path_buffer, "error", printf_buffer) != 0) {
+ printk("xenbus: failed to write error node for %s (%s)\n",
+ dev->nodename, printf_buffer);
+ goto fail;
+ }
+
+fail:
+ if (printf_buffer)
+ kfree(printf_buffer);
+ if (path_buffer)
+ kfree(path_buffer);
}
EXPORT_SYMBOL(xenbus_dev_error);
@@ -551,11 +583,21 @@
void xenbus_dev_ok(struct xenbus_device *dev)
{
if (dev->has_error) {
- if (xenbus_rm(NULL, dev->nodename, "error") != 0)
+ char *path_buffer = error_path(dev);
+
+ if (path_buffer == NULL) {
+ printk("xenbus: failed to clear error node for %s: "
+ "%d\n", dev->nodename, errno);
+ return;
+ }
+
+ if (xenbus_rm(NULL, path_buffer, "error") != 0)
printk("xenbus: failed to clear error node for %s\n",
dev->nodename);
else
dev->has_error = 0;
+
+ kfree(path_buffer);
}
}
EXPORT_SYMBOL(xenbus_dev_ok);
diff -r 2c0b3b807756 -r 5a728a884242 tools/examples/xen-backend.agent
--- a/tools/examples/xen-backend.agent Sun Oct 23 15:54:51 2005
+++ b/tools/examples/xen-backend.agent Sun Oct 23 21:34:13 2005
@@ -15,9 +15,13 @@
vbd)
/etc/xen/scripts/block unbind
;;
+ vif)
+ [ -n "$script" ] && $script down
+ ;;
esac
# remove device backend store entries
xenstore-rm -t "$XENBUS_PATH"
+ xenstore-rm -t "error/$XENBUS_PATH"
;;
online)
case "$XENBUS_TYPE" in
diff -r 2c0b3b807756 -r 5a728a884242 tools/python/xen/util/diagnose.py
--- a/tools/python/xen/util/diagnose.py Sun Oct 23 15:54:51 2005
+++ b/tools/python/xen/util/diagnose.py Sun Oct 23 21:34:13 2005
@@ -107,7 +107,9 @@
print ("Cannot find backend path for device %s, %s." %
(deviceClass, device))
else:
- backend_error = xstransact.Read(backendPath, 'error')
+ backend_error = xstransact.Read(
+ backendPath.replace('backend/', 'error/backend/'),
+ 'error')
if backend_error:
diagnose_device_error(backend_error)
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