5 files changed, 84 insertions, 16 deletions

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 51ceaee98f9f..e1e7143ca1e3 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -335,7 +335,7 @@ static void cciss_map_sg_chain_block(ctlr_info_t *h, CommandList_struct *c,
 static const char *raid_label[] = { "0", "4", "1(1+0)", "5", "5+1", "ADG",
 	"UNKNOWN"
 };
-#define RAID_UNKNOWN (sizeof(raid_label) / sizeof(raid_label[0])-1)
+#define RAID_UNKNOWN (ARRAY_SIZE(raid_label)-1)
 
 #ifdef CONFIG_PROC_FS
 
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index dff48701b84d..ec1711f7c5c5 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1087,7 +1087,7 @@ static enum finish_epoch drbd_may_finish_epoch(struct drbd_conf *mdev,
 			} else {
 				epoch->flags = 0;
 				atomic_set(&epoch->epoch_size, 0);
-				/* atomic_set(&epoch->active, 0); is alrady zero */
+				/* atomic_set(&epoch->active, 0); is already zero */
 				if (rv == FE_STILL_LIVE)
 					rv = FE_RECYCLED;
 			}
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 218d091f3c52..16c3c8613cd3 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -4,7 +4,7 @@
  * Note that you can not swap over this thing, yet. Seems to work but
  * deadlocks sometimes - you can not swap over TCP in general.
  * 
- * Copyright 1997-2000, 2008 Pavel Machek <pavel@suse.cz>
+ * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
  * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
  *
  * This file is released under GPLv2 or later.
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 258bc2ae2885..23b7c48df843 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -225,16 +225,6 @@ static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
 	struct gendisk *disk = bdev->bd_disk;
 	struct virtio_blk *vblk = disk->private_data;
 
-	if (cmd == 0x56424944) { /* 'VBID' */
-		void __user *usr_data = (void __user *)data;
-		char id_str[VIRTIO_BLK_ID_BYTES];
-		int err;
-
-		err = virtblk_get_id(disk, id_str);
-		if (!err && copy_to_user(usr_data, id_str, VIRTIO_BLK_ID_BYTES))
-			err = -EFAULT;
-		return err;
-	}
 	/*
 	 * Only allow the generic SCSI ioctls if the host can support it.
 	 */
@@ -281,6 +271,27 @@ static int index_to_minor(int index)
 	return index << PART_BITS;
 }
 
+static ssize_t virtblk_serial_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+	int err;
+
+	/* sysfs gives us a PAGE_SIZE buffer */
+	BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
+
+	buf[VIRTIO_BLK_ID_BYTES] = '\0';
+	err = virtblk_get_id(disk, buf);
+	if (!err)
+		return strlen(buf);
+
+	if (err == -EIO) /* Unsupported? Make it empty. */
+		return 0;
+
+	return err;
+}
+DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
+
 static int __devinit virtblk_probe(struct virtio_device *vdev)
 {
 	struct virtio_blk *vblk;
@@ -366,12 +377,32 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
 	vblk->disk->driverfs_dev = &vdev->dev;
 	index++;
 
-	/* If barriers are supported, tell block layer that queue is ordered */
-	if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
+	if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) {
+		/*
+		 * If the FLUSH feature is supported we do have support for
+		 * flushing a volatile write cache on the host.  Use that
+		 * to implement write barrier support.
+		 */
 		blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH,
 				  virtblk_prepare_flush);
-	else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
+	} else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER)) {
+		/*
+		 * If the BARRIER feature is supported the host expects us
+		 * to order request by tags.  This implies there is not
+		 * volatile write cache on the host, and that the host
+		 * never re-orders outstanding I/O.  This feature is not
+		 * useful for real life scenarious and deprecated.
+		 */
 		blk_queue_ordered(q, QUEUE_ORDERED_TAG, NULL);
+	} else {
+		/*
+		 * If the FLUSH feature is not supported we must assume that
+		 * the host does not perform any kind of volatile write
+		 * caching. We still need to drain the queue to provider
+		 * proper barrier semantics.
+		 */
+		blk_queue_ordered(q, QUEUE_ORDERED_DRAIN, NULL);
+	}
 
 	/* If disk is read-only in the host, the guest should obey */
 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
@@ -445,8 +476,15 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
 
 
 	add_disk(vblk->disk);
+	err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
+	if (err)
+		goto out_del_disk;
+
 	return 0;
 
+out_del_disk:
+	del_gendisk(vblk->disk);
+	blk_cleanup_queue(vblk->disk->queue);
 out_put_disk:
 	put_disk(vblk->disk);
 out_mempool:
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 82ed403147c0..f63ac3d1f8a4 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -48,6 +48,7 @@
 #include <xen/grant_table.h>
 #include <xen/events.h>
 #include <xen/page.h>
+#include <xen/platform_pci.h>
 
 #include <xen/interface/grant_table.h>
 #include <xen/interface/io/blkif.h>
@@ -737,6 +738,35 @@ static int blkfront_probe(struct xenbus_device *dev,
 		}
 	}
 
+	if (xen_hvm_domain()) {
+		char *type;
+		int len;
+		/* no unplug has been done: do not hook devices != xen vbds */
+		if (xen_platform_pci_unplug & XEN_UNPLUG_IGNORE) {
+			int major;
+
+			if (!VDEV_IS_EXTENDED(vdevice))
+				major = BLKIF_MAJOR(vdevice);
+			else
+				major = XENVBD_MAJOR;
+
+			if (major != XENVBD_MAJOR) {
+				printk(KERN_INFO
+						"%s: HVM does not support vbd %d as xen block device\n",
+						__FUNCTION__, vdevice);
+				return -ENODEV;
+			}
+		}
+		/* do not create a PV cdrom device if we are an HVM guest */
+		type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
+		if (IS_ERR(type))
+			return -ENODEV;
+		if (strncmp(type, "cdrom", 5) == 0) {
+			kfree(type);
+			return -ENODEV;
+		}
+		kfree(type);
+	}
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info) {
 		xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");