Commit 22a1ffea authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Jens Axboe
Browse files

block: add IOC_PR_READ_KEYS ioctl 



Add a Persistent Reservations ioctl to read the list of currently
registered reservation keys. This calls the pr_ops->read_keys() function
that was previously added in commit c787f1ba ("block: Add PR
callouts for read keys and reservation") but was only used by the
in-kernel SCSI target so far.

The IOC_PR_READ_KEYS ioctl is necessary so that userspace applications
that rely on Persistent Reservations ioctls have a way of inspecting the
current state. Cluster managers and validation tests need this
functionality.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 38ec8469

block/ioctl.c

+56 −0
Original line number Diff line number Diff line
@@ -423,6 +423,60 @@ static int blkdev_pr_clear(struct block_device *bdev, blk_mode_t mode, 
	return ops->pr_clear(bdev, c.key);

}



static int blkdev_pr_read_keys(struct block_device *bdev, blk_mode_t mode,

		struct pr_read_keys __user *arg)

{

	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;

	struct pr_keys *keys_info;

	struct pr_read_keys read_keys;

	u64 __user *keys_ptr;

	size_t keys_info_len;

	size_t keys_copy_len;

	int ret;



	if (!blkdev_pr_allowed(bdev, mode))

		return -EPERM;

	if (!ops || !ops->pr_read_keys)

		return -EOPNOTSUPP;



	if (copy_from_user(&read_keys, arg, sizeof(read_keys)))

		return -EFAULT;



	keys_info_len = struct_size(keys_info, keys, read_keys.num_keys);

	if (keys_info_len == SIZE_MAX)

		return -EINVAL;



	keys_info = kzalloc(keys_info_len, GFP_KERNEL);

	if (!keys_info)

		return -ENOMEM;



	keys_info->num_keys = read_keys.num_keys;



	ret = ops->pr_read_keys(bdev, keys_info);

	if (ret)

		goto out;



	/* Copy out individual keys */

	keys_ptr = u64_to_user_ptr(read_keys.keys_ptr);

	keys_copy_len = min(read_keys.num_keys, keys_info->num_keys) *

		        sizeof(keys_info->keys[0]);



	if (copy_to_user(keys_ptr, keys_info->keys, keys_copy_len)) {

		ret = -EFAULT;

		goto out;

	}



	/* Copy out the arg struct */

	read_keys.generation = keys_info->generation;

	read_keys.num_keys = keys_info->num_keys;



	if (copy_to_user(arg, &read_keys, sizeof(read_keys)))

		ret = -EFAULT;

out:

	kfree(keys_info);

	return ret;

}



static int blkdev_flushbuf(struct block_device *bdev, unsigned cmd,

		unsigned long arg)

{
@@ -645,6 +699,8 @@ static int blkdev_common_ioctl(struct block_device *bdev, blk_mode_t mode, 
		return blkdev_pr_preempt(bdev, mode, argp, true);

	case IOC_PR_CLEAR:

		return blkdev_pr_clear(bdev, mode, argp);

	case IOC_PR_READ_KEYS:

		return blkdev_pr_read_keys(bdev, mode, argp);

	default:

		return blk_get_meta_cap(bdev, cmd, argp);

	}

include/uapi/linux/pr.h

+7 −0
Original line number Diff line number Diff line
@@ -56,6 +56,12 @@ struct pr_clear { 
	__u32	__pad;

};



struct pr_read_keys {

	__u32	generation;

	__u32	num_keys;

	__u64	keys_ptr;

};



#define PR_FL_IGNORE_KEY	(1 << 0)	/* ignore existing key */



#define IOC_PR_REGISTER		_IOW('p', 200, struct pr_registration)
@@ -64,5 +70,6 @@ struct pr_clear { 
#define IOC_PR_PREEMPT		_IOW('p', 203, struct pr_preempt)

#define IOC_PR_PREEMPT_ABORT	_IOW('p', 204, struct pr_preempt)

#define IOC_PR_CLEAR		_IOW('p', 205, struct pr_clear)

#define IOC_PR_READ_KEYS	_IOWR('p', 206, struct pr_read_keys)



#endif /* _UAPI_PR_H */