I cant reproduce it with 4.6.5 kernel any more. The nfs related changes are: NFS: Fix another OPEN_DOWNGRADE bug (e547f2628327fec6afd2e03b46f113f614cca05b) NFS: Fix a double page unlock (cbebaf897e5c4862567eb799dc84acc5d7ee2678) The second one fixes the source of missing close in 4.6. I will try to chase it RHEL7. Tigran. ----- Original Message ----- > From: "Olga Kornievskaia" <aglo@xxxxxxxxx> > To: "Mkrtchyan, Tigran" <tigran.mkrtchyan@xxxxxxx> > Cc: "Andy Adamson" <William.Adamson@xxxxxxxxxx>, "Linux NFS Mailing List" <linux-nfs@xxxxxxxxxxxxxxx>, "Trond Myklebust" > <trond.myklebust@xxxxxxxxxxxxxxx>, "Steve Dickson" <steved@xxxxxxxxxx> > Sent: Thursday, August 4, 2016 11:20:54 PM > Subject: Re: Lost CLOSE with NFSv4.1 on RHEL7 ( and bejond?) > On Thu, Aug 4, 2016 at 3:00 PM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote: >> On Thu, Aug 4, 2016 at 11:04 AM, Mkrtchyan, Tigran >> <tigran.mkrtchyan@xxxxxxx> wrote: >>> >>> Hi Olga et al. >>> >>> Finally I was able to to create a reproducer (attached)! >>> >>> It looks like, if on close client application is interrupted by >>> Ctrl+C or SIGINT, then nfs client does not sends CLOSE. I can >>> 100% reproduce it on RHEL7 and Fedora24 with 4.6 kernel. The 4.7 >>> kernel works (side effect of some other change?). >>> >>> The attached application reads file in a loop. On the second >>> iteration a thread is started, which will send SIGINT >>> to itself. When CLOSE is lost, you still can read the >>> file. Client even won't send any OPEN. So it looks like >>> that some where file is marked as open, but corresponding >>> process does not exist any more. Even re-mount does not help. >>> >> >> Thank you Tigran for a reproducer, I'll check it out and get back to you. > > I tried your example. I ran this on 3.10.0-327.4.4. In my run, I see > OPEN, GETLAYOUT, GETDEVINFO, READ, CLOSE. Since I get a delegation, > then when the file is read again, there won't be able an OPEN on the > network trace in the next loop iteration. There won't be a read as > it'll be read from the cache. So I'm not should what ctrl-c is > accomplishing. What am I missing? > > Thanks. > >> >>> Best regards, >>> Tigran. >>> >>> ----- Original Message ----- >>>> From: "Olga Kornievskaia" <aglo@xxxxxxxxx> >>>> To: "Mkrtchyan, Tigran" <tigran.mkrtchyan@xxxxxxx> >>>> Cc: "Andy Adamson" <William.Adamson@xxxxxxxxxx>, "Linux NFS Mailing List" >>>> <linux-nfs@xxxxxxxxxxxxxxx>, "Trond Myklebust" >>>> <trond.myklebust@xxxxxxxxxxxxxxx>, "Steve Dickson" <steved@xxxxxxxxxx> >>>> Sent: Monday, August 1, 2016 11:22:10 PM >>>> Subject: Re: Lost CLOSE with NFSv4.1 on RHEL7 ( and bejond?) >>> >>>> On Mon, Aug 1, 2016 at 7:08 AM, Mkrtchyan, Tigran >>>> <tigran.mkrtchyan@xxxxxxx> wrote: >>>>> Hi Olga, >>>>> >>>>> we have installed kernel 4.7.0 on one of the nodes and don't see missing >>>>> closes from that node. >>>>> >>>>> Nevertheless, I don't think that the commit you have mentioned is fixing that, >>>>> as it fixes OPEN_DOWNGRADE, but we have a sequence of OPEN->CLOSE->OPEN. The >>>>> OPEN_DOWNGRADE is not expected - file is already closed when a second open >>>>> is sent and both requests using the same session slot. >>>>> >>>>> Have you seen a similar issue on vanilla or rhel kernel? >>>> >>>> I had a hard time triggering it consistently. I believe I have seen it >>>> on RHEL7.2 kernel but I think I was more consistently seeing it on >>>> some upstream (Trond's) kernel version (I think it was around 4.2). >>>> The problem was seen by Netapp QA on 4.3-rc7 version. >>>> >>>> Thanks for testing on the 4.7 version. I'll see what else went in that >>>> might explain the failure on the older kernel. >>>> >>>>> >>>>> Thanks a lot, >>>>> Tigran. >>>>> >>>>> ----- Original Message ----- >>>>>> From: "Olga Kornievskaia" <aglo@xxxxxxxxx> >>>>>> To: "Mkrtchyan, Tigran" <tigran.mkrtchyan@xxxxxxx> >>>>>> Cc: "Andy Adamson" <William.Adamson@xxxxxxxxxx>, "Linux NFS Mailing List" >>>>>> <linux-nfs@xxxxxxxxxxxxxxx>, "Trond Myklebust" >>>>>> <trond.myklebust@xxxxxxxxxxxxxxx>, "Steve Dickson" <steved@xxxxxxxxxx> >>>>>> Sent: Thursday, July 14, 2016 4:52:59 PM >>>>>> Subject: Re: Lost CLOSE with NFSv4.1 on RHEL7 ( and bejond?) >>>>> >>>>>> Hi Tigran, >>>>>> >>>>>> On Wed, Jul 13, 2016 at 12:49 PM, Mkrtchyan, Tigran >>>>>> <tigran.mkrtchyan@xxxxxxx> wrote: >>>>>>> >>>>>>> >>>>>>> Hi Andy, >>>>>>> >>>>>>> I will try to get upstream kernel on one of the nodes. It will take >>>>>>> some time as we need to add a new host into the cluster and get >>>>>>> some traffic go through it. >>>>>>> >>>>>>> In the mean while, with RHEL7 we get it easy reproduced - about 10 >>>>>>> such cases per day. Is there any tool that will help us to see where >>>>>>> it happens? Some traces points? Call trace from vfs close to NFS close? >>>>>> >>>>>> There are NFS tracepoints but I don't know think there are VFS >>>>>> tracepoints. Unfortunately, there was a bug in the OPEN tracepoints >>>>>> that caused a kernel crash. I had a bugzilla out for RHEL7.2. It says >>>>>> it's fixed in the later kernel (.381) but it's currently not back >>>>>> ported to RHEL7.2z but hopefully will be soon (just chatted with Steve >>>>>> about getting the fix into zstream). I made no progress in figuring >>>>>> out what could be causing the lack of CLOSE and it was hard for me to >>>>>> reproduce. >>>>>> >>>>>> Just recently Trond fixed a problem where a CLOSE that was suppose to >>>>>> be sent as an OPEN_DOWNGRADE wasn't sent (commit 0979bc2a59) . I >>>>>> wonder if that can be fixing this problem.... >>>>>> >>>>>>> There is a one comment in the kernel code, which sounds similar: >>>>>>> (http://git.linux-nfs.org/?p=trondmy/linux-nfs.git;a=blob;f=fs/nfs/nfs4proc.c;h=519368b987622ea23bea210929bebfd0c327e14e;hb=refs/heads/linux-next#l2955) >>>>>>> >>>>>>> nfs4proc.c: 2954 >>>>>>> ==== >>>>>>> >>>>>>> /* >>>>>>> * It is possible for data to be read/written from a mem-mapped file >>>>>>> * after the sys_close call (which hits the vfs layer as a flush). >>>>>>> * This means that we can't safely call nfsv4 close on a file until >>>>>>> * the inode is cleared. This in turn means that we are not good >>>>>>> * NFSv4 citizens - we do not indicate to the server to update the file's >>>>>>> * share state even when we are done with one of the three share >>>>>>> * stateid's in the inode. >>>>>>> * >>>>>>> * NOTE: Caller must be holding the sp->so_owner semaphore! >>>>>>> */ >>>>>>> int nfs4_do_close(struct nfs4_state *state, gfp_t gfp_mask, int wait) >>>>>>> >>>>>> >>>>>> I'm not sure if the comment means to say that there is a possibility >>>>>> that NFS won't send a CLOSE (or at least I hope not). I thought that >>>>>> because we keep a reference count on the inode and send the CLOSE when >>>>>> it goes down to 0. Basically the last WRITE will trigger the nfs close >>>>>> not the vfs_close. >>>>>> >>>>>> >>>>>>> ==== >>>>>>> >>>>>>> >>>>>>> Tigran. >>>>>>> >>>>>>> >>>>>>> ----- Original Message ----- >>>>>>>> From: "Andy Adamson" <William.Adamson@xxxxxxxxxx> >>>>>>>> To: "Mkrtchyan, Tigran" <tigran.mkrtchyan@xxxxxxx> >>>>>>>> Cc: "Linux NFS Mailing List" <linux-nfs@xxxxxxxxxxxxxxx>, "Andy Adamson" >>>>>>>> <William.Adamson@xxxxxxxxxx>, "Trond Myklebust" >>>>>>>> <trond.myklebust@xxxxxxxxxxxxxxx>, "Steve Dickson" <steved@xxxxxxxxxx> >>>>>>>> Sent: Tuesday, July 12, 2016 7:16:19 PM >>>>>>>> Subject: Re: Lost CLOSE with NFSv4.1 on RHEL7 ( and bejond?) >>>>>>> >>>>>>>> Hi Tigran >>>>>>>> >>>>>>>> Can you test with an upstream kernel? Olga has seen issues around no CLOSE being >>>>>>>> sent - it is really hard to reproduce…. >>>>>>>> >>>>>>>> —>Andy >>>>>>>> >>>>>>>> >>>>>>>>> On Jul 7, 2016, at 6:49 AM, Mkrtchyan, Tigran <tigran.mkrtchyan@xxxxxxx> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Dear NFS folks, >>>>>>>>> >>>>>>>>> we observe orphan open-states on our deployment with nfsv4.1. >>>>>>>>> Our setup - two client nodes, running RHEL-7.2 with kernel >>>>>>>>> 3.10.0-327.22.2.el7.x86_64. Both nodes running ownCloud (like >>>>>>>>> a dropbox) which nfsv4.1 mounts to dCache storage. Some clients >>>>>>>>> connected to node1, others to node2. >>>>>>>>> >>>>>>>>> Time-to-time we see some 'active' transfers on data our DS >>>>>>>>> which do nothing. There is a corresponding state on MDS. >>>>>>>>> >>>>>>>>> I have traced one one such cases: >>>>>>>>> >>>>>>>>> - node1 uploads the file. >>>>>>>>> - node2 reads the file couple of times, OPEN+LAYOUTGET+CLOSE >>>>>>>>> - node2 sends OPEN+LAYOUTGET >>>>>>>>> - there is no open file on node2 which points to it. >>>>>>>>> - CLOSE never send to the server. >>>>>>>>> - node1 eventually removes the removes the file >>>>>>>>> >>>>>>>>> We have many other cases where file is not removed, but this one I was >>>>>>>>> able to trace. The link to capture files: >>>>>>>>> >>>>>>>>> https://desycloud.desy.de/index.php/s/YldowcRzTGJeLbN >>>>>>>>> >>>>>>>>> We had ~ 10^6 transfers in last 2 days and 29 files in such state (~0.0029%). >>>>>>>>> >>>>>>>> > Tigran. >>>>>>> -- >>>>>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >>>>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>>>> -- >>>>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >>>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
