block: restore multiple bd_link_disk_holder() support

Commit Message

Tejun Heo Jan. 13, 2011, 5:21 p.m. UTC

None

Patch

Index: work/include/linux/fs.h
===================================================================
--- work.orig/include/linux/fs.h
+++ work/include/linux/fs.h
@@ -663,9 +663,6 @@  struct block_device {
 	void *			bd_holder;
 	int			bd_holders;
 	bool			bd_write_holder;
-#ifdef CONFIG_SYSFS
-	struct gendisk *	bd_holder_disk;	/* for sysfs slave linkng */
-#endif
 	struct block_device *	bd_contains;
 	unsigned		bd_block_size;
 	struct hd_struct *	bd_part;
@@ -2045,12 +2042,18 @@  extern struct block_device *blkdev_get_b
 extern int blkdev_put(struct block_device *bdev, fmode_t mode);
 #ifdef CONFIG_SYSFS
 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
+extern void bd_unlink_disk_holder(struct block_device *bdev,
+				  struct gendisk *disk);
 #else
 static inline int bd_link_disk_holder(struct block_device *bdev,
 				      struct gendisk *disk)
 {
 	return 0;
 }
+static inline void bd_unlink_disk_holder(struct block_device *bdev,
+					 struct gendisk *disk)
+{
+}
 #endif
 #endif
 
Index: work/drivers/md/dm-table.c
===================================================================
--- work.orig/drivers/md/dm-table.c
+++ work/drivers/md/dm-table.c
@@ -347,6 +347,7 @@  static void close_dev(struct dm_dev_inte
 	if (!d->dm_dev.bdev)
 		return;
 
+	bd_unlink_disk_holder(d->dm_dev.bdev, dm_disk(md));
 	blkdev_put(d->dm_dev.bdev, d->dm_dev.mode | FMODE_EXCL);
 	d->dm_dev.bdev = NULL;
 }
Index: work/drivers/md/md.c
===================================================================
--- work.orig/drivers/md/md.c
+++ work/drivers/md/md.c
@@ -1907,6 +1907,7 @@  static void unbind_rdev_from_array(mdk_r
 		MD_BUG();
 		return;
 	}
+	bd_unlink_disk_holder(rdev->bdev, rdev->mddev->gendisk);
 	list_del_rcu(&rdev->same_set);
 	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
 	rdev->mddev = NULL;
Index: work/fs/block_dev.c
===================================================================
--- work.orig/fs/block_dev.c
+++ work/fs/block_dev.c
@@ -788,6 +788,8 @@  static void del_symlink(struct kobject *
  * @bdev: the claimed slave bdev
  * @disk: the holding disk
  *
+ * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
+ *
  * This functions creates the following sysfs symlinks.
  *
  * - from "slaves" directory of the holder @disk to the claimed @bdev
@@ -815,7 +817,7 @@  int bd_link_disk_holder(struct block_dev
 
 	mutex_lock(&bdev->bd_mutex);
 
-	WARN_ON_ONCE(!bdev->bd_holder || bdev->bd_holder_disk);
+	WARN_ON_ONCE(!bdev->bd_holder);
 
 	/* FIXME: remove the following once add_disk() handles errors */
 	if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir))
@@ -831,27 +833,28 @@  int bd_link_disk_holder(struct block_dev
 		goto out_unlock;
 	}
 
-	bdev->bd_holder_disk = disk;
 out_unlock:
 	mutex_unlock(&bdev->bd_mutex);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(bd_link_disk_holder);
 
-static void bd_unlink_disk_holder(struct block_device *bdev)
+/**
+ * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
+ * @bdev: the calimed slave bdev
+ * @disk: the holding disk
+ *
+ * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
+ *
+ * CONTEXT:
+ * Might sleep.
+ */
+void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 {
-	struct gendisk *disk = bdev->bd_holder_disk;
-
-	bdev->bd_holder_disk = NULL;
-	if (!disk)
-		return;
-
 	del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
 	del_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
 }
-#else
-static inline void bd_unlink_disk_holder(struct block_device *bdev)
-{ }
+EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
 #endif
 
 /**
@@ -1374,7 +1377,6 @@  int blkdev_put(struct block_device *bdev
 		 * unblock evpoll if it was a write holder.
 		 */
 		if (bdev_free) {
-			bd_unlink_disk_holder(bdev);
 			if (bdev->bd_write_holder) {
 				disk_unblock_events(bdev->bd_disk);
 				bdev->bd_write_holder = false;