On Thu, Jun 9, 2022 at 12:18 PM Xiubo Li <xiubli@xxxxxxxxxx> wrote: > > > On 6/9/22 12:02 PM, Yan, Zheng wrote: > > On Thu, Jun 9, 2022 at 11:56 AM Xiubo Li <xiubli@xxxxxxxxxx> wrote: > >> > >> On 6/9/22 11:29 AM, Yan, Zheng wrote: > >>> On Thu, Jun 9, 2022 at 11:19 AM Xiubo Li <xiubli@xxxxxxxxxx> wrote: > >>>> On 6/9/22 10:15 AM, Yan, Zheng wrote: > >>>>> The recent series of patches that add "wait on async xxxx" at various > >>>>> places do not seem correct. The correct fix should make mds avoid any > >>>>> wait when handling async requests. > >>>>> > >>>> In this case I am thinking what will happen if the async create request > >>>> is deferred, then the cap flush related request should fail to find the > >>>> ino. > >>>> > >>>> Should we wait ? Then how to distinguish from migrating a subtree and a > >>>> deferred async create cases ? > >>>> > >>> async op caps are revoked at freezingtree stage of subtree migration. > >>> see Locker::invalidate_lock_caches > >>> > >> Sorry I may not totally understand this issue. > >> > >> I think you mean in case of migration and then the MDS will revoke caps > >> for the async create files and then the kclient will send a MclientCap > >> request to mds, right ? > >> > >> If my understanding is correct, there is another case that: > >> > >> 1, async create a fileA > >> > >> 2, then write a lot of data to it and then release the Fw cap ref, and > >> if we should report the size to MDS, it will send a MclientCap request > >> to MDS too. > >> > >> 3, what if the async create of fileA was deferred due to some reason, > >> then the MclientCap request will fail to find the ino ? > >> > > Async op should not be deferred in any case. > > Recently we have hit a similar bug, caused by deferring a request and > requeuing it and the following request was executed before it. > that bug is mds bug. > >>>>> On Wed, Jun 8, 2022 at 12:56 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote: > >>>>>> Currently, we'll call ceph_check_caps, but if we're still waiting on the > >>>>>> reply, we'll end up spinning around on the same inode in > >>>>>> flush_dirty_session_caps. Wait for the async create reply before > >>>>>> flushing caps. > >>>>>> > >>>>>> Fixes: fbed7045f552 (ceph: wait for async create reply before sending any cap messages) > >>>>>> URL: https://tracker.ceph.com/issues/55823 > >>>>>> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > >>>>>> --- > >>>>>> fs/ceph/caps.c | 1 + > >>>>>> 1 file changed, 1 insertion(+) > >>>>>> > >>>>>> I don't know if this will fix the tx queue stalls completely, but I > >>>>>> haven't seen one with this patch in place. I think it makes sense on its > >>>>>> own, either way. > >>>>>> > >>>>>> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c > >>>>>> index 0a48bf829671..5ecfff4b37c9 100644 > >>>>>> --- a/fs/ceph/caps.c > >>>>>> +++ b/fs/ceph/caps.c > >>>>>> @@ -4389,6 +4389,7 @@ static void flush_dirty_session_caps(struct ceph_mds_session *s) > >>>>>> ihold(inode); > >>>>>> dout("flush_dirty_caps %llx.%llx\n", ceph_vinop(inode)); > >>>>>> spin_unlock(&mdsc->cap_dirty_lock); > >>>>>> + ceph_wait_on_async_create(inode); > >>>>>> ceph_check_caps(ci, CHECK_CAPS_FLUSH, NULL); > >>>>>> iput(inode); > >>>>>> spin_lock(&mdsc->cap_dirty_lock); > >>>>>> -- > >>>>>> 2.36.1 > >>>>>> >
