rbd: add 'minor' sysfs rbd device attribute
Introduce /sys/bus/rbd/devices/<id>/minor sysfs attribute for exporting
rbd whole disk minor numbers. This is a step towards single-major
device number allocation scheme, but also a good thing on its own.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
diff --git a/Documentation/ABI/testing/sysfs-bus-rbd b/Documentation/ABI/testing/sysfs-bus-rbd
index 0a30647..17b119c 100644
--- a/Documentation/ABI/testing/sysfs-bus-rbd
+++ b/Documentation/ABI/testing/sysfs-bus-rbd
@@ -33,6 +33,10 @@
The block device major number.
+minor
+
+ The block device minor number. (December 2013, since 3.14.)
+
name
The name of the rbd image.
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index d250549..01ed767 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -323,6 +323,7 @@
int dev_id; /* blkdev unique id */
int major; /* blkdev assigned major */
+ int minor;
struct gendisk *disk; /* blkdev's gendisk and rq */
u32 image_format; /* Either 1 or 2 */
@@ -3397,7 +3398,7 @@
snprintf(disk->disk_name, sizeof(disk->disk_name), RBD_DRV_NAME "%d",
rbd_dev->dev_id);
disk->major = rbd_dev->major;
- disk->first_minor = 0;
+ disk->first_minor = rbd_dev->minor;
disk->fops = &rbd_bd_ops;
disk->private_data = rbd_dev;
@@ -3469,7 +3470,14 @@
return sprintf(buf, "%d\n", rbd_dev->major);
return sprintf(buf, "(none)\n");
+}
+static ssize_t rbd_minor_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
+
+ return sprintf(buf, "%d\n", rbd_dev->minor);
}
static ssize_t rbd_client_id_show(struct device *dev,
@@ -3591,6 +3599,7 @@
static DEVICE_ATTR(size, S_IRUGO, rbd_size_show, NULL);
static DEVICE_ATTR(features, S_IRUGO, rbd_features_show, NULL);
static DEVICE_ATTR(major, S_IRUGO, rbd_major_show, NULL);
+static DEVICE_ATTR(minor, S_IRUGO, rbd_minor_show, NULL);
static DEVICE_ATTR(client_id, S_IRUGO, rbd_client_id_show, NULL);
static DEVICE_ATTR(pool, S_IRUGO, rbd_pool_show, NULL);
static DEVICE_ATTR(pool_id, S_IRUGO, rbd_pool_id_show, NULL);
@@ -3604,6 +3613,7 @@
&dev_attr_size.attr,
&dev_attr_features.attr,
&dev_attr_major.attr,
+ &dev_attr_minor.attr,
&dev_attr_client_id.attr,
&dev_attr_pool.attr,
&dev_attr_pool_id.attr,
@@ -4848,6 +4858,7 @@
if (ret < 0)
goto err_out_id;
rbd_dev->major = ret;
+ rbd_dev->minor = 0;
/* Set up the blkdev mapping. */