rbd: add support for single-major device number allocation scheme (9b60e70b) · Commits · 戴 / test

Documentation/ABI/testing/sysfs-bus-rbd

+22 −0

Original line number	Diff line number	Diff line
		@@ -18,6 +18,28 @@ Removal of a device:

		$ echo <dev-id> > /sys/bus/rbd/remove

		What: /sys/bus/rbd/add_single_major
		Date: December 2013
		KernelVersion: 3.14
		Contact: Sage Weil <sage@inktank.com>
		Description: Available only if rbd module is inserted with single_major
		parameter set to true.
		Usage is the same as for /sys/bus/rbd/add. If present,
		should be used instead of the latter: any attempts to use
		/sys/bus/rbd/add if /sys/bus/rbd/add_single_major is
		available will fail for backwards compatibility reasons.

		What: /sys/bus/rbd/remove_single_major
		Date: December 2013
		KernelVersion: 3.14
		Contact: Sage Weil <sage@inktank.com>
		Description: Available only if rbd module is inserted with single_major
		parameter set to true.
		Usage is the same as for /sys/bus/rbd/remove. If present,
		should be used instead of the latter: any attempts to use
		/sys/bus/rbd/remove if /sys/bus/rbd/remove_single_major is
		available will fail for backwards compatibility reasons.

		Entries under /sys/bus/rbd/devices/<dev-id>/
		--------------------------------------------

drivers/block/rbd.c

+112 −20

Original line number	Diff line number	Diff line
		@@ -91,7 +91,7 @@ static int atomic_dec_return_safe(atomic_t *v)

		#define RBD_DRV_NAME "rbd"

		#define RBD_MINORS_PER_MAJOR 256 /* max minors per blkdev */
		#define RBD_PART_SHIFT 8

		#define RBD_SNAP_DEV_NAME_PREFIX "snap_"
		#define RBD_MAX_SNAP_NAME_LEN \
		@@ -387,8 +387,17 @@ static struct kmem_cache *rbd_img_request_cache;
		static struct kmem_cache *rbd_obj_request_cache;
		static struct kmem_cache *rbd_segment_name_cache;

		static int rbd_major;
		static DEFINE_IDA(rbd_dev_id_ida);

		/*
		* Default to false for now, as single-major requires >= 0.75 version of
		* userspace rbd utility.
		*/
		static bool single_major = false;
		module_param(single_major, bool, S_IRUGO);
		MODULE_PARM_DESC(single_major, "Use a single major number for all rbd devices (default: false)");

		static int rbd_img_request_submit(struct rbd_img_request *img_request);

		static void rbd_dev_device_release(struct device *dev);
		@@ -397,21 +406,44 @@ static ssize_t rbd_add(struct bus_type bus, const char buf,
		size_t count);
		static ssize_t rbd_remove(struct bus_type bus, const char buf,
		size_t count);
		static ssize_t rbd_add_single_major(struct bus_type bus, const char buf,
		size_t count);
		static ssize_t rbd_remove_single_major(struct bus_type bus, const char buf,
		size_t count);
		static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping);
		static void rbd_spec_put(struct rbd_spec *spec);

		static int rbd_dev_id_to_minor(int dev_id)
		{
		return dev_id << RBD_PART_SHIFT;
		}

		static int minor_to_rbd_dev_id(int minor)
		{
		return minor >> RBD_PART_SHIFT;
		}

		static BUS_ATTR(add, S_IWUSR, NULL, rbd_add);
		static BUS_ATTR(remove, S_IWUSR, NULL, rbd_remove);
		static BUS_ATTR(add_single_major, S_IWUSR, NULL, rbd_add_single_major);
		static BUS_ATTR(remove_single_major, S_IWUSR, NULL, rbd_remove_single_major);

		static struct attribute *rbd_bus_attrs[] = {
		&bus_attr_add.attr,
		&bus_attr_remove.attr,
		&bus_attr_add_single_major.attr,
		&bus_attr_remove_single_major.attr,
		NULL,
		};

		static umode_t rbd_bus_is_visible(struct kobject *kobj,
		struct attribute *attr, int index)
		{
		if (!single_major &&
		(attr == &bus_attr_add_single_major.attr \|\|
		attr == &bus_attr_remove_single_major.attr))
		return 0;

		return attr->mode;
		}

		@@ -3402,7 +3434,7 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
		u64 segment_size;

		/* create gendisk info */
		disk = alloc_disk(RBD_MINORS_PER_MAJOR);
		disk = alloc_disk(1 << RBD_PART_SHIFT);
		if (!disk)
		return -ENOMEM;

		@@ -4403,7 +4435,9 @@ static int rbd_dev_id_get(struct rbd_device *rbd_dev)
		{
		int new_dev_id;

		new_dev_id = ida_simple_get(&rbd_dev_id_ida, 0, 0, GFP_KERNEL);
		new_dev_id = ida_simple_get(&rbd_dev_id_ida,
		0, minor_to_rbd_dev_id(1 << MINORBITS),
		GFP_KERNEL);
		if (new_dev_id < 0)
		return new_dev_id;

		@@ -4863,13 +4897,19 @@ static int rbd_dev_device_setup(struct rbd_device *rbd_dev)
		< sizeof (RBD_DRV_NAME) + MAX_INT_FORMAT_WIDTH);
		sprintf(rbd_dev->name, "%s%d", RBD_DRV_NAME, rbd_dev->dev_id);

		/* Get our block major device number. */
		/* Record our major and minor device numbers. */

		if (!single_major) {
		ret = register_blkdev(0, rbd_dev->name);
		if (ret < 0)
		goto err_out_id;

		rbd_dev->major = ret;
		rbd_dev->minor = 0;
		} else {
		rbd_dev->major = rbd_major;
		rbd_dev->minor = rbd_dev_id_to_minor(rbd_dev->dev_id);
		}

		/* Set up the blkdev mapping. */

		@@ -4901,6 +4941,7 @@ err_out_mapping:
		err_out_disk:
		rbd_free_disk(rbd_dev);
		err_out_blkdev:
		if (!single_major)
		unregister_blkdev(rbd_dev->major, rbd_dev->name);
		err_out_id:
		rbd_dev_id_put(rbd_dev);
		@@ -5022,7 +5063,7 @@ err_out_format:
		return ret;
		}

		static ssize_t rbd_add(struct bus_type *bus,
		static ssize_t do_rbd_add(struct bus_type *bus,
		const char *buf,
		size_t count)
		{
		@@ -5106,6 +5147,23 @@ err_out_module:
		return (ssize_t)rc;
		}

		static ssize_t rbd_add(struct bus_type *bus,
		const char *buf,
		size_t count)
		{
		if (single_major)
		return -EINVAL;

		return do_rbd_add(bus, buf, count);
		}

		static ssize_t rbd_add_single_major(struct bus_type *bus,
		const char *buf,
		size_t count)
		{
		return do_rbd_add(bus, buf, count);
		}

		static void rbd_dev_device_release(struct device *dev)
		{
		struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
		@@ -5113,8 +5171,8 @@ static void rbd_dev_device_release(struct device *dev)
		rbd_free_disk(rbd_dev);
		clear_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags);
		rbd_dev_mapping_clear(rbd_dev);
		if (!single_major)
		unregister_blkdev(rbd_dev->major, rbd_dev->name);
		rbd_dev->major = 0;
		rbd_dev_id_put(rbd_dev);
		rbd_dev_mapping_clear(rbd_dev);
		}
		@@ -5145,7 +5203,7 @@ static void rbd_dev_remove_parent(struct rbd_device *rbd_dev)
		}
		}

		static ssize_t rbd_remove(struct bus_type *bus,
		static ssize_t do_rbd_remove(struct bus_type *bus,
		const char *buf,
		size_t count)
		{
		@@ -5210,6 +5268,23 @@ static ssize_t rbd_remove(struct bus_type *bus,
		return count;
		}

		static ssize_t rbd_remove(struct bus_type *bus,
		const char *buf,
		size_t count)
		{
		if (single_major)
		return -EINVAL;

		return do_rbd_remove(bus, buf, count);
		}

		static ssize_t rbd_remove_single_major(struct bus_type *bus,
		const char *buf,
		size_t count)
		{
		return do_rbd_remove(bus, buf, count);
		}

		/*
		* create control files in sysfs
		* /sys/bus/rbd/...
		@@ -5298,13 +5373,28 @@ static int __init rbd_init(void)
		if (rc)
		return rc;

		if (single_major) {
		rbd_major = register_blkdev(0, RBD_DRV_NAME);
		if (rbd_major < 0) {
		rc = rbd_major;
		goto err_out_slab;
		}
		}

		rc = rbd_sysfs_init();
		if (rc)
		goto err_out_slab;
		goto err_out_blkdev;

		if (single_major)
		pr_info("loaded (major %d)\n", rbd_major);
		else
		pr_info("loaded\n");

		return 0;

		err_out_blkdev:
		if (single_major)
		unregister_blkdev(rbd_major, RBD_DRV_NAME);
		err_out_slab:
		rbd_slab_exit();
		return rc;
		@@ -5313,6 +5403,8 @@ err_out_slab:
		static void __exit rbd_exit(void)
		{
		rbd_sysfs_cleanup();
		if (single_major)
		unregister_blkdev(rbd_major, RBD_DRV_NAME);
		rbd_slab_exit();
		}

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