On Mon, Jul 1, 2019 at 7:34 AM Dongsheng Yang
<dongsheng.yang@xxxxxxxxxxxx> wrote:
>
> Hi Ilya,
>
> On 06/25/2019 10:40 PM, Ilya Dryomov wrote:
> > Hello,
> >
> > This series adds support for object-map and fast-diff image features.
> > Patches 1 - 11 prepare object and image request state machines; patches
> > 12 - 14 fix most of the shortcomings in our exclusive lock code, making
> > it suitable for guarding the object map; patches 15 - 18 take care of
> > the prerequisites and finally patches 19 - 20 implement object-map and
> > fast-diff.
>
> Nice patchset. I did review and a testing for this patchset.
Hi Dongsheng,
Thank you!
>
> TEST:
> with object-map enabled, I found a case failed:
> tasks/rbd_kernel.yaml.
> It failed to rollback test_img while test_img is mapped.
This is because with object map reads grab the lock:
67 rbd resize testimg1 --size=40 --allow-shrink
68 cat /sys/bus/rbd/devices/$DEV_ID1/size | grep 41943040
69 cat /sys/bus/rbd/devices/$DEV_ID2/size | grep 76800000
70
71 sudo dd if=/dev/rbd/rbd/testimg1 of=/tmp/img1.small
72 cp /tmp/img1 /tmp/img1.trunc
73 truncate -s 41943040 /tmp/img1.trunc
74 cmp /tmp/img1.trunc /tmp/img1.small
75
76 # rollback and check data again
77 rbd snap rollback --snap=snap1 testimg1
Without object map the lock is freed by resize on line 67 and rollback
executes on an unlocked image. With object map we re-grab the lock for
dd on line 71 and rollback executes on a locked image.
rollback isn't supposed to work on a locked image, so it's just an
accident that this test continued to work after exclusive lock was
introduced in 4.9.
Another test that will need to be fixed is krbd_exclusive_option.sh.
This one fails both with and without object-map feature because we no
longer block if the peer refuses to release the lock.
I'm on vacation and didn't get a chance to update the test suite yet.
Ilya
