> On May 14, 2018, at 16:37, Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
>
> On Sat, May 12, 2018 at 1:38 AM, Yan, Zheng <zyan@xxxxxxxxxx> wrote:
>>
>>
>>> On May 11, 2018, at 20:06, Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
>>>
>>> On Fri, May 11, 2018 at 11:12 AM, Yan, Zheng <zyan@xxxxxxxxxx> wrote:
>>>> this avoid force umount getting stuck at ceph_osdc_sync()
>>>>
>>>> Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
>>>> ---
>>>> fs/ceph/super.c | 1 +
>>>> include/linux/ceph/osd_client.h | 5 ++++-
>>>> net/ceph/osd_client.c | 43 ++++++++++++++++++++++++++++++++++++-----
>>>> 3 files changed, 43 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
>>>> index 3c1155803444..40664e13cc0f 100644
>>>> --- a/fs/ceph/super.c
>>>> +++ b/fs/ceph/super.c
>>>> @@ -793,6 +793,7 @@ static void ceph_umount_begin(struct super_block *sb)
>>>> if (!fsc)
>>>> return;
>>>> fsc->mount_state = CEPH_MOUNT_SHUTDOWN;
>>>> + ceph_osdc_abort_requests(&fsc->client->osdc, -EIO);
>>>> ceph_mdsc_force_umount(fsc->mdsc);
>>>> return;
>>>> }
>>>> diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
>>>> index b73dd7ebe585..f61736963236 100644
>>>> --- a/include/linux/ceph/osd_client.h
>>>> +++ b/include/linux/ceph/osd_client.h
>>>> @@ -347,6 +347,7 @@ struct ceph_osd_client {
>>>> struct rb_root linger_map_checks;
>>>> atomic_t num_requests;
>>>> atomic_t num_homeless;
>>>> + int abort_code;
>>>
>>> Why osdc->abort_code and all __submit_request() hunks are needed?
>>> If we are in a forced umount situation, no new I/Os should be accepted
>>> anyway.
>>
>> No code guarantees that ceph_writepages_start()/writepage_nounlock() are
>> not being executed when user does forced umount. They may start new
>> osd requests after forced umount.
>
> I haven't traced through forced umount steps, but it seems like there
> must be a point where we stop accepting requests and attempt to quiesce
> the state.
>
To support this, cephfs code needs to introduce a rwsem, read lock the rwsem before calling ceph_osdc_wait_request(). Besides, the rwsem can not be used in the cases of blocking osdc functions (such as ceph_osdc_readpages). So I think it’s better to implement this in libceph.
> The patch talks about avoiding getting stuck in ceph_osdc_sync().
> Is it guaranteed that no new OSD requests can be started after it
> completes?
>
No, it doesn’t.
Regards
Yan, Zheng
> Thanks,
>
> Ilya
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
