Commit e7407d16 authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds

block: bd_link_disk_holder() should hold on to holder_dir

The new implementation of bd_link_disk_holder() added by 49731baa
(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: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatar"Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
Tested-by: default avatar"Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8074b26f
...@@ -873,6 +873,11 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) ...@@ -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); ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
if (ret) if (ret)
goto out_del; 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); list_add(&holder->list, &bdev->bd_holder_disks);
goto out_unlock; goto out_unlock;
...@@ -909,6 +914,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) ...@@ -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(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
del_symlink(bdev->bd_part->holder_dir, del_symlink(bdev->bd_part->holder_dir,
&disk_to_dev(disk)->kobj); &disk_to_dev(disk)->kobj);
kobject_put(bdev->bd_part->holder_dir);
list_del_init(&holder->list); list_del_init(&holder->list);
kfree(holder); kfree(holder);
} }
......
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