On Tue, Feb 21, 2017 at 06:09:56PM +0100, Jan Kara wrote: > When block device is closed, we call inode_detach_wb() in __blkdev_put() > which sets inode->i_wb to NULL. That is contrary to expectations that > inode->i_wb stays valid once set during the whole inode's lifetime and > leads to oops in wb_get() in locked_inode_to_wb_and_lock_list() because > inode_to_wb() returned NULL. > > The reason why we called inode_detach_wb() is not valid anymore though. > BDI is guaranteed to stay along until we call bdi_put() from > bdev_evict_inode() so we can postpone calling inode_detach_wb() to that > moment. > > Also add a warning to catch if someone uses inode_detach_wb() in a > dangerous way. > > Reported-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Jan Kara <jack@xxxxxxx> Acked-by: Tejun Heo <tj@xxxxxxxxxx> Thanks. -- tejun
