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
