On Sat, Jul 20, 2013 at 09:48:28AM -0500, Mike Christie wrote:

What about the attached only compile tested patch. The patch has the mq
block code work like the non mq code for bio cleanups.

Not sure if it is related to the patch or not, but it never returns from
wait_for_completion_io(&wait) in blkdev_issue_flush():

# ps axl | awk '$10 ~ /D\+/'
4     0   938   879  20   0 111216   656 blkdev D+   pts/1      0:00 fdisk/dev/sda
#
# cat /proc/938/stack
[<ffffffff812a8a5c>] blkdev_issue_flush+0xfc/0x160
[<ffffffff811ac606>] blkdev_fsync+0x96/0xc0
[<ffffffff811a2f4d>] do_fsync+0x5d/0x90
[<ffffffff811a3330>] SyS_fsync+0x10/0x20
[<ffffffff81611582>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff

Any ideas?

Thanks!

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com