[4.8 hang] xfstests generic/361 hangs on dax enabled filesystems

[Dan Williams]

On Wed, Aug 3, 2016 at 4:16 PM, Dave Chinner <david at fromorbit.com> wrote:
> On Wed, Aug 03, 2016 at 04:37:13PM -0600, Ross Zwisler wrote:
>> On Wed, Aug 03, 2016 at 11:11:27AM -0600, Ross Zwisler wrote:
>> > On Wed, Aug 03, 2016 at 10:33:54AM +1000, Dave Chinner wrote:
>> > > Hi folks,
>> > >
>> > > Just hit a reproducable hang in generic/361. Essentially this on
>> > > a 8GB pmem device:
>> > >
>> > > mkfs.xfs -f /dev/pmem1
>> > > mount -o dax /dev/pmem1 /mnt/scratch
>> > > xfs_io -f -c "truncate 1g" test.img
>> > > losetup -f --show /mnt/scratch/test.img
>> > > mkfs.xfs -f /dev/loop0
>> > >
>> > > And the mkfs.xfs command hangs with a discard that never completes:
> ....
>> > > This only reproduces when the underlying filesystem is mounted with
>> > > -o dax, so there is a bad interaction with loop devices and DAX
>> > > occurring somewhere. generic/361 is a recent test (committed june 14)
>> > > so this probably hasn't actually been tested until now.
>> > >
>> > > I haven't got time to look at this right now, hence the report.
>> >
>> > Cool, thanks for the report.  I've reproduced this with linux/master, and the
>> > test passes with v4.7.
>> >
>> > Running a bisect...
>>
>> This bisected to a commit to the block layer code.  I've sent a bug report to
>> the author of the commit.
>
> And the commit id is ...?

c2df40dfb8c0 drivers: use req op accessor