From: Tejun Heo Date: Thu, 24 Feb 2011 08:56:32 +0000 (+0100) Subject: block: bd_link_disk_holder() should hold on to holder_dir X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=e7407d1619713f4b1fdff3a485e1bd8e77bd480d;p=linux-beck.git 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 --- 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); del_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); + kobject_put(bdev->bd_part->holder_dir); list_del_init(&holder->list); kfree(holder); }