diff options
authorTejun Heo <>2011-02-24 09:56:32 +0100
committerLinus Torvalds <>2011-02-24 08:55:55 -0800
commite7407d1619713f4b1fdff3a485e1bd8e77bd480d (patch)
parent8074b26f67165bf045d92e778c9c10dc5e207fc6 (diff)
block: bd_link_disk_holder() should hold on to holder_dir
The new implementation of bd_link_disk_holder() added by 49731baa41d (block: restore multiple bd_link_disk_holder() support) didn't get an extra reference for the holder_dir kobject of the slave bdev; however, bdev kills holder_dir on removal, not release, so if the slave bdev is removed while there are holder links, the holder_dir will be destroyed while there still are holder links, which leads to oops later when bd_unlink_disk_order() tries to remove those links. Make bd_link_disk_holder() grab an extra reference for the slave's holder_dir and put it in bd_unlink_disk_holder(). Signed-off-by: Tejun Heo <> Reported-by: "Hawrylewicz Czarnowski, Przemyslaw" <> Tested-by: "Hawrylewicz Czarnowski, Przemyslaw" <> Cc: Neil Brown <> Cc: Jens Axboe <> Signed-off-by: Linus Torvalds <>
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 4fb8a3431531..94d41db62004 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -873,6 +873,11 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
if (ret)
goto out_del;
+ /*
+ * bdev could be deleted beneath us which would implicitly destroy
+ * the holder directory. Hold on to it.
+ */
+ kobject_get(bdev->bd_part->holder_dir);
list_add(&holder->list, &bdev->bd_holder_disks);
goto out_unlock;
@@ -909,6 +914,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+ kobject_put(bdev->bd_part->holder_dir);