Merge branch 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block

* 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block: (149 commits)
  block: make sure that REQ_* types are seen even with CONFIG_BLOCK=n
  xen-blkfront: fix missing out label
  blkdev: fix blkdev_issue_zeroout return value
  block: update request stacking methods to support discards
  block: fix missing export of blk_types.h
  writeback: fix bad _bh spinlock nesting
  drbd: revert "delay probes", feature is being re-implemented differently
  drbd: Initialize all members of sync_conf to their defaults [Bugz 315]
  drbd: Disable delay probes for the upcomming release
  writeback: cleanup bdi_register
  writeback: add new tracepoints
  writeback: remove unnecessary init_timer call
  writeback: optimize periodic bdi thread wakeups
  writeback: prevent unnecessary bdi threads wakeups
  writeback: move bdi threads exiting logic to the forker thread
  writeback: restructure bdi forker loop a little
  writeback: move last_active to bdi
  writeback: do not remove bdi from bdi_list
  writeback: simplify bdi code a little
  writeback: do not lose wake-ups in bdi threads
  ...

Fixed up pretty trivial conflicts in drivers/block/virtio_blk.c and
drivers/scsi/scsi_error.c as per Jens.

1 files changed, 66 insertions, 24 deletions

diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 7b3e973a1ae..7e49527189b 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -133,17 +133,12 @@ int xenbus_watch_pathfmt(struct xenbus_device *dev,
 }
 EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt);
 
+static void xenbus_switch_fatal(struct xenbus_device *, int, int,
+				const char *, ...);
 
-/**
- * xenbus_switch_state
- * @dev: xenbus device
- * @state: new state
- *
- * Advertise in the store a change of the given driver to the given new_state.
- * Return 0 on success, or -errno on error.  On error, the device will switch
- * to XenbusStateClosing, and the error will be saved in the store.
- */
-int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
+static int
+__xenbus_switch_state(struct xenbus_device *dev,
+		      enum xenbus_state state, int depth)
 {
 	/* We check whether the state is currently set to the given value, and
 	   if not, then the state is set.  We don't want to unconditionally
@@ -152,35 +147,65 @@ int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
 	   to it, as the device will be tearing down, and we don't want to
 	   resurrect that directory.
 
-	   Note that, because of this cached value of our state, this function
-	   will not work inside a Xenstore transaction (something it was
-	   trying to in the past) because dev->state would not get reset if
-	   the transaction was aborted.
-
+	   Note that, because of this cached value of our state, this
+	   function will not take a caller's Xenstore transaction
+	   (something it was trying to in the past) because dev->state
+	   would not get reset if the transaction was aborted.
 	 */
 
+	struct xenbus_transaction xbt;
 	int current_state;
-	int err;
+	int err, abort;
 
 	if (state == dev->state)
 		return 0;
 
-	err = xenbus_scanf(XBT_NIL, dev->nodename, "state", "%d",
-			   &current_state);
-	if (err != 1)
+again:
+	abort = 1;
+
+	err = xenbus_transaction_start(&xbt);
+	if (err) {
+		xenbus_switch_fatal(dev, depth, err, "starting transaction");
 		return 0;
+	}
+
+	err = xenbus_scanf(xbt, dev->nodename, "state", "%d", &current_state);
+	if (err != 1)
+		goto abort;
 
-	err = xenbus_printf(XBT_NIL, dev->nodename, "state", "%d", state);
+	err = xenbus_printf(xbt, dev->nodename, "state", "%d", state);
 	if (err) {
-		if (state != XenbusStateClosing) /* Avoid looping */
-			xenbus_dev_fatal(dev, err, "writing new state");
-		return err;
+		xenbus_switch_fatal(dev, depth, err, "writing new state");
+		goto abort;
 	}
 
-	dev->state = state;
+	abort = 0;
+abort:
+	err = xenbus_transaction_end(xbt, abort);
+	if (err) {
+		if (err == -EAGAIN && !abort)
+			goto again;
+		xenbus_switch_fatal(dev, depth, err, "ending transaction");
+	} else
+		dev->state = state;
 
 	return 0;
 }
+
+/**
+ * xenbus_switch_state
+ * @dev: xenbus device
+ * @state: new state
+ *
+ * Advertise in the store a change of the given driver to the given new_state.
+ * Return 0 on success, or -errno on error.  On error, the device will switch
+ * to XenbusStateClosing, and the error will be saved in the store.
+ */
+int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
+{
+	return __xenbus_switch_state(dev, state, 0);
+}
+
 EXPORT_SYMBOL_GPL(xenbus_switch_state);
 
 int xenbus_frontend_closed(struct xenbus_device *dev)
@@ -284,6 +309,23 @@ void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...)
 EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
 
 /**
+ * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps
+ * avoiding recursion within xenbus_switch_state.
+ */
+static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
+				const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	xenbus_va_dev_error(dev, err, fmt, ap);
+	va_end(ap);
+
+	if (!depth)
+		__xenbus_switch_state(dev, XenbusStateClosing, 1);
+}
+
+/**
  * xenbus_grant_ring
  * @dev: xenbus device
  * @ring_mfn: mfn of ring to grant