Hello, this is a series with the remaining patches (on top of 4.11-rc2) to fix several different races and issues I've found when testing device shutdown and reuse. The first two patches fix possible (theoretical) problems when opening of a block device races with shutdown of a gendisk structure. Patches 3-9 fix oops that is triggered by __blkdev_put() calling inode_detach_wb() too early (the problem reported by Thiago). Patches 10 and 11 fix oops due to a bug in gendisk code where get_gendisk() can return already freed gendisk structure (again triggered by Omar's stress test). People, please have a look at patches. They are mostly simple however the interactions are rather complex so I may have missed something. Also I'm happy for any additional testing these patches can get - I've stressed them with Omar's script, tested memcg writeback, tested static (not udev managed) device inodes. Changes since v3: * Rebased on top of 4.11-rc2 * Reworked patch 2 (block: Fix race of bdev open with gendisk shutdown) based on Tejun's feedback * Significantly updated patch 5 (and dropped previous Tejun's ack) to accommodate for fixes to SCSI re-registration of BDI that went to 4.11-rc2 Changes since v2: * Added Tejun's acks * Rebased on top of 4.11-rc1 * Fixed two possible races between blkdev_open() and del_gendisk() * Fixed possible race between concurrent shutdown of cgwb spotted by Tejun Changes since v1: * Added Acks and Tested-by tags for patches in areas that did not change * Reworked inode_detach_wb() related fixes based on Tejun's feedback Honza
