[PATCH] infrastructure

	* added ->media_changed(disk).  Callers of ->check_media_changed()
are using that one if present
	* added ->revaldiate_disk(disk).  Callers of ->revalidate()
are using that one if present
	* added disk->queue.  do_open() uses it if non-NULL
	* added disk->private_data
	* removed assignments to inode->i_data.backing_... - it belongs to
filesystem that contains device node and we don't care about it;
inode->i_mapping points to ->i_data of bdev inode and there we should
(and do) set that field.

fs/block_dev.c

@@ -527,15 +527,20 @@ int check_disk_change(struct block_device *bdev)
 	struct block_device_operations * bdops = bdev->bd_op;
 	kdev_t dev = to_kdev_t(bdev->bd_dev);
 
+	if (!bdops->media_changed) {
 		if (bdops->check_media_change == NULL)
 			return 0;
 		if (!bdops->check_media_change(dev))
 			return 0;
+	} else if (!bdops->media_changed(bdev->bd_disk))
+		return 0;
 
 	if (invalidate_device(dev, 0))
 		printk("VFS: busy inodes on changed media.\n");
 
-	if (bdops->revalidate)
+	if (bdops->revalidate_disk)
+		bdops->revalidate_disk(bdev->bd_disk);
+	else if (bdops->revalidate)
 		bdops->revalidate(dev);
 	if (bdev->bd_disk->minors > 1)
 		bdev->bd_invalidated = 1;
@@ -633,11 +638,15 @@ static int do_open(struct block_device *bdev, struct inode *inode, struct file *
 		if (!bdev->bd_openers)
 			bdev->bd_disk = disk;
 		if (!bdev->bd_queue) {
+			if (disk->queue)
+				bdev->bd_queue = disk->queue;
+			else {
 				struct blk_dev_struct *p = blk_dev + major(dev);
 				bdev->bd_queue = &p->request_queue;
 				if (p->queue)
 					bdev->bd_queue =  p->queue(dev);
 			}
+		}
 		if (bdev->bd_op->open) {
 			ret = bdev->bd_op->open(inode, file);
 			if (ret)
@@ -650,7 +659,6 @@ static int do_open(struct block_device *bdev, struct inode *inode, struct file *
 			bdi = blk_get_backing_dev_info(bdev);
 			if (bdi == NULL)
 				bdi = &default_backing_dev_info;
-			inode->i_data.backing_dev_info = bdi;
 			bdev->bd_inode->i_data.backing_dev_info = bdi;
 		}
 		if (bdev->bd_invalidated)
@@ -661,7 +669,6 @@ static int do_open(struct block_device *bdev, struct inode *inode, struct file *
 		if (!bdev->bd_openers) {
 			struct hd_struct *p;
 			p = disk->part + part - 1;
-			inode->i_data.backing_dev_info =
 			bdev->bd_inode->i_data.backing_dev_info =
 			   bdev->bd_contains->bd_inode->i_data.backing_dev_info;
 			if (!(disk->flags & GENHD_FL_UP) || !p->nr_sects) {
@@ -685,6 +692,8 @@ static int do_open(struct block_device *bdev, struct inode *inode, struct file *
 
 out2:
 	if (!bdev->bd_openers) {
+		bdev->bd_queue = NULL;
+		bdev->bd_disk = NULL;
 		bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
 		if (bdev != bdev->bd_contains) {
 			blkdev_put(bdev->bd_contains, BDEV_RAW);

fs/partitions/check.c

@@ -511,7 +511,9 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 	bdev->bd_invalidated = 0;
 	for (p = 1; p < disk->minors; p++)
 		delete_partition(disk, p);
-	if (bdev->bd_op->revalidate)
+	if (bdev->bd_op->revalidate_disk)
+		bdev->bd_op->revalidate_disk(disk);
+	else if (bdev->bd_op->revalidate)
 		bdev->bd_op->revalidate(dev);
 	if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
 		return res;

include/linux/fs.h

@@ -732,6 +732,8 @@ struct block_device_operations {
 	int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);
 	int (*check_media_change) (kdev_t);
 	int (*revalidate) (kdev_t);
+	int (*media_changed) (struct gendisk *);
+	int (*revalidate_disk) (struct gendisk *);
 	struct module *owner;
 };
 

include/linux/genhd.h

@@ -80,6 +80,8 @@ struct gendisk {
 	char disk_name[16];		/* name of major driver */
 	struct hd_struct *part;		/* [indexed by minor] */
 	struct block_device_operations *fops;
+	struct request_queue *queue;
+	void *private_data;
 	sector_t capacity;
 	struct list_head list;
 	struct list_head full_list;