From 392a840799f83ac8fadd051ac6663106712ad35d Mon Sep 17 00:00:00 2001
From: Daniel Stodden <daniel.stodden@citrix.com>
Date: Sat, 7 Aug 2010 18:45:12 +0200
Subject: [PATCH] --- yaml --- r: 208286 b: refs/heads/master c:
 7fd152f4b6ae4f3cf89e4b7a0383cc3c470772fc h: refs/heads/master v: v3

---
 [refs]                             |  2 +-
 trunk/drivers/block/xen-blkfront.c | 49 ++++++++++++++++++++----------
 2 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/[refs] b/[refs]
index 6c8edf338461..c49e7938e353 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 139617437aff1f0d3b57c2d7cc60e60efc8fe6c3
+refs/heads/master: 7fd152f4b6ae4f3cf89e4b7a0383cc3c470772fc
diff --git a/trunk/drivers/block/xen-blkfront.c b/trunk/drivers/block/xen-blkfront.c
index 763a315712cc..49862993f31e 100644
--- a/trunk/drivers/block/xen-blkfront.c
+++ b/trunk/drivers/block/xen-blkfront.c
@@ -1142,31 +1142,48 @@ static int blkif_open(struct block_device *bdev, fmode_t mode)
 	if (!err)
 		++info->users;
 
-	unlock_kernel();
 out:
+	unlock_kernel();
 	return err;
 }
 
 static int blkif_release(struct gendisk *disk, fmode_t mode)
 {
 	struct blkfront_info *info = disk->private_data;
+	struct block_device *bdev;
+	struct xenbus_device *xbdev;
+
 	lock_kernel();
-	info->users--;
-	if (info->users == 0) {
-		/* Check whether we have been instructed to close.  We will
-		   have ignored this request initially, as the device was
-		   still mounted. */
-		struct xenbus_device *dev = info->xbdev;
-
-		if (!dev) {
-			xlvbd_release_gendisk(info);
-			kfree(info);
-		} else if (xenbus_read_driver_state(dev->otherend)
-			   == XenbusStateClosing && info->is_ready) {
-			xlvbd_release_gendisk(info);
-			xenbus_frontend_closed(dev);
-		}
+	if (--info->users)
+		goto out;
+
+	bdev = bdget_disk(disk, 0);
+	bdput(bdev);
+
+	/*
+	 * Check if we have been instructed to close. We will have
+	 * deferred this request, because the bdev was still open.
+	 */
+
+	mutex_lock(&info->mutex);
+	xbdev = info->xbdev;
+
+	if (xbdev && xbdev->state == XenbusStateClosing) {
+		/* pending switch to state closed */
+		xlvbd_release_gendisk(info);
+		xenbus_frontend_closed(info->xbdev);
+ 	}
+
+	mutex_unlock(&info->mutex);
+
+	if (!xbdev) {
+		/* sudden device removal */
+		xlvbd_release_gendisk(info);
+		disk->private_data = NULL;
+		kfree(info);
 	}
+
+out:
 	unlock_kernel();
 	return 0;
 }