From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
This patch makes sure blkfront handles correctly virtual device numbers
corresponding to Xen emulated IDE and SCSI disks: in those cases
blkfront translates the major number to XENVBD and the minor number to a
low xvd minor.
Note: this behaviour is different from what old xenlinux PV guests used
to do: they used to steal an IDE or SCSI major number and use it
instead.
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Acked-by: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
---
drivers/block/xen-blkfront.c | 79 +++++++++++++++++++++++++++++++++++--
include/xen/interface/io/blkif.h | 21 ++++++++++
2 files changed, 95 insertions(+), 5 deletions(-)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index d7aa39e..64d9c6d 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -120,6 +120,10 @@ static DEFINE_SPINLOCK(minor_lock);
#define EXTENDED (1<<EXT_SHIFT)
#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
+#define EMULATED_HD_DISK_MINOR_OFFSET (0)
+#define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
+#define EMULATED_SD_DISK_MINOR_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET + (4 *
16))
+#define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_HD_DISK_NAME_OFFSET + 4)
#define DEV_NAME "xvd" /* name in /dev */
@@ -434,6 +438,65 @@ static void xlvbd_flush(struct blkfront_info *info)
info->feature_flush ? "enabled" : "disabled");
}
+static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
+{
+ int major;
+ major = BLKIF_MAJOR(vdevice);
+ *minor = BLKIF_MINOR(vdevice);
+ switch (major) {
+ case XEN_IDE0_MAJOR:
+ *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
+ *minor = ((*minor / 64) * PARTS_PER_DISK) +
+ EMULATED_HD_DISK_MINOR_OFFSET;
+ break;
+ case XEN_IDE1_MAJOR:
+ *offset = (*minor / 64) + 2 +
EMULATED_HD_DISK_NAME_OFFSET;
+ *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
+ EMULATED_HD_DISK_MINOR_OFFSET;
+ break;
+ case XEN_SCSI_DISK0_MAJOR:
+ *offset = (*minor / PARTS_PER_DISK) +
EMULATED_SD_DISK_NAME_OFFSET;
+ *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
+ break;
+ case XEN_SCSI_DISK1_MAJOR:
+ case XEN_SCSI_DISK2_MAJOR:
+ case XEN_SCSI_DISK3_MAJOR:
+ case XEN_SCSI_DISK4_MAJOR:
+ case XEN_SCSI_DISK5_MAJOR:
+ case XEN_SCSI_DISK6_MAJOR:
+ case XEN_SCSI_DISK7_MAJOR:
+ *offset = (*minor / PARTS_PER_DISK) +
+ ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
+ EMULATED_SD_DISK_NAME_OFFSET;
+ *minor = *minor +
+ ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 *
PARTS_PER_DISK) +
+ EMULATED_SD_DISK_MINOR_OFFSET;
+ break;
+ case XEN_SCSI_DISK8_MAJOR:
+ case XEN_SCSI_DISK9_MAJOR:
+ case XEN_SCSI_DISK10_MAJOR:
+ case XEN_SCSI_DISK11_MAJOR:
+ case XEN_SCSI_DISK12_MAJOR:
+ case XEN_SCSI_DISK13_MAJOR:
+ case XEN_SCSI_DISK14_MAJOR:
+ case XEN_SCSI_DISK15_MAJOR:
+ *offset = (*minor / PARTS_PER_DISK) +
+ ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
+ EMULATED_SD_DISK_NAME_OFFSET;
+ *minor = *minor +
+ ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 *
PARTS_PER_DISK) +
+ EMULATED_SD_DISK_MINOR_OFFSET;
+ break;
+ case XENVBD_MAJOR:
+ *offset = *minor / PARTS_PER_DISK;
+ break;
+ default:
+ printk(KERN_WARNING "blkfront: your disk configuration
is "
+ "incorrect, please use an xvd device
instead\n");
+ return -ENODEV;
+ }
+ return 0;
+}
static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
struct blkfront_info *info,
@@ -441,7 +504,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
{
struct gendisk *gd;
int nr_minors = 1;
- int err = -ENODEV;
+ int err;
unsigned int offset;
int minor;
int nr_parts;
@@ -456,12 +519,20 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
}
if (!VDEV_IS_EXTENDED(info->vdevice)) {
- minor = BLKIF_MINOR(info->vdevice);
- nr_parts = PARTS_PER_DISK;
+ err = xen_translate_vdev(info->vdevice, &minor, &offset);
+ if (err)
+ return err;
+ nr_parts = PARTS_PER_DISK;
} else {
minor = BLKIF_MINOR_EXT(info->vdevice);
nr_parts = PARTS_PER_EXT_DISK;
+ offset = minor / nr_parts;
+ if (xen_hvm_domain() && offset <= EMULATED_HD_DISK_NAME_OFFSET
+ 4)
+ printk(KERN_WARNING "blkfront: vdevice 0x%x might
conflict with "
+ "emulated IDE disks,\n\t choose an xvd
device name"
+ "from xvde on\n", info->vdevice);
}
+ err = -ENODEV;
if ((minor % nr_parts) == 0)
nr_minors = nr_parts;
@@ -475,8 +546,6 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
if (gd == NULL)
goto release;
- offset = minor / nr_parts;
-
if (nr_minors > 1) {
if (offset < 26)
sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h
index c2d1fa4..68dd2b4 100644
--- a/include/xen/interface/io/blkif.h
+++ b/include/xen/interface/io/blkif.h
@@ -91,4 +91,25 @@ DEFINE_RING_TYPES(blkif, struct blkif_request, struct
blkif_response);
#define VDISK_REMOVABLE 0x2
#define VDISK_READONLY 0x4
+/* Xen-defined major numbers for virtual disks, they look strangely
+ * familiar */
+#define XEN_IDE0_MAJOR 3
+#define XEN_IDE1_MAJOR 22
+#define XEN_SCSI_DISK0_MAJOR 8
+#define XEN_SCSI_DISK1_MAJOR 65
+#define XEN_SCSI_DISK2_MAJOR 66
+#define XEN_SCSI_DISK3_MAJOR 67
+#define XEN_SCSI_DISK4_MAJOR 68
+#define XEN_SCSI_DISK5_MAJOR 69
+#define XEN_SCSI_DISK6_MAJOR 70
+#define XEN_SCSI_DISK7_MAJOR 71
+#define XEN_SCSI_DISK8_MAJOR 128
+#define XEN_SCSI_DISK9_MAJOR 129
+#define XEN_SCSI_DISK10_MAJOR 130
+#define XEN_SCSI_DISK11_MAJOR 131
+#define XEN_SCSI_DISK12_MAJOR 132
+#define XEN_SCSI_DISK13_MAJOR 133
+#define XEN_SCSI_DISK14_MAJOR 134
+#define XEN_SCSI_DISK15_MAJOR 135
+
#endif /* __XEN_PUBLIC_IO_BLKIF_H__ */
--
1.5.6.5
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