Hello Dan,

Am Freitag, 6. Januar 2017, 17:02:51 BRST schrieb Dan Williams:

v1 of these changes [1] was a one line change to bdev_get_queue() to
prevent a shutdown crash when del_gendisk() races the final
__blkdev_put().

While it is known at del_gendisk() time that the queue is still alive,
Jan Kara points to other paths [2] that are racing __blkdev_put() where
the assumption that ->bd_queue, or inode->i_wb is valid does not hold.

Fix that broken assumption, make it the case that if you have a live
block_device, or block_device-inode that the corresponding queue and
inode-write-back data is still valid.

These changes survive a run of the libnvdimm unit test suite which puts
some stress on the block_device shutdown path.

I realize that the kernel test robot found problems with this series, but FWIW 
it fixes the bug mentioned in [2].

[1]: http://marc.info/?l=linux-block&m=148366637105761&w=2
[2]: http://www.spinics.net/lists/linux-fsdevel/msg105153.html

-- 
Thiago Jung Bauermann
IBM Linux Technology Center