block: add a new set_read_only method

Add a new method to allow for driver-specific processing when setting or clearing the block device read-only state. This allows to replace the cumbersome and error-prone override of the whole ioctl implementation. Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
berg · Nov 16, 2020 · e00adca · e00adca
1 parent 4a9d6d6
commit e00adca
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diff --git a/block/ioctl.c b/block/ioctl.c
@@ -389,6 +389,11 @@ static int blkdev_roset(struct block_device *bdev, fmode_t mode,
 		return ret;
 	if (get_user(n, (int __user *)arg))
 		return -EFAULT;
+	if (bdev->bd_disk->fops->set_read_only) {
+		ret = bdev->bd_disk->fops->set_read_only(bdev, n);
+		if (ret)
+			return ret;
+	}
 	set_device_ro(bdev, n);
 	return 0;
 }

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
@@ -1850,6 +1850,7 @@ struct block_device_operations {
 	void (*unlock_native_capacity) (struct gendisk *);
 	int (*revalidate_disk) (struct gendisk *);
 	int (*getgeo)(struct block_device *, struct hd_geometry *);
+	int (*set_read_only)(struct block_device *bdev, bool ro);
 	/* this callback is with swap_lock and sometimes page table lock held */
 	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
 	int (*report_zones)(struct gendisk *, sector_t sector,