On Tue, Mar 15, 2016 at 10:21:04AM +0100, Sascha Frey wrote: > Hi list, > > we're experiencing a serious NFSv4 client caching issue when a > client reads a file which was deleted and recreated by another client. > > Steps to reproduce the problem: > > root@client1:~# mount -t nfs -o rw,vers=4,sec=sys,hard,intr 129.70.150.53:/vol/testvol5 /mnt > root@client2:~# mount -t nfs -o rw,vers=4,sec=sys,hard,intr 129.70.150.53:/vol/testvol5 /mnt > > user@client1:~$ echo foo > /mnt/bar >From the trace. Everything is NFSv4.0: > user@client2:~$ cat /mnt/bar > foo Here we see successful OPEN, OPEN_CONFIRM, READ, CLOSE. The open does not return a delegation. > user@client1:~$ rm /mnt/bar ; echo quux > /mnt/bar > user@client2:~$ cat /mnt/bar > cat: /mnt/bar: Input/output error Here a compound with [PUTFH(fh from open), ACCESS] returns [OK, NFS4ERR_NOFILEHANDLE]. I believe that's a server-side bug: the server should instead return NFS4ERR_STALE to the PUTFH. (I'm not actually sure why the client's sending an access--isn't it going to have to send an OPEN next anyway?--but anyway it's not doing anything illegal.) --b. > > Even after waiting some hours the i/o error is still there. > 'ls' on target directory fixes the problem immediately: > > user@client2:~$ ls /mnt > bar > user@client2:~$ cat /mnt/bar > quux > > Dropping the inode cache also works: > root@client2:~# sync > root@client2:~# echo 2 > /proc/sys/vm/drop_caches > > > We tried different mount options (lookupcache=none, noac, ...), > but nothing helped. > > NFS server: EMC ISILON NAS cluster > > Clients: Ubuntu 14.04 LTS > Kernels tried: Ubuntu linux-image-3.16.0-40-generic, vanilla 3.18.1, > vanilla 4.4.0 > > Also affected: > - Debian Jessie (kernel 3.16) > - Ubuntu 16.04 beta/alpha (Ubuntu kernel 4.4.0-12-generic) > > No affected: > - CentOS 6 (kernel 2.6.32) > - Debian Wheezy (kernel 3.2) > > This problem does only occur when using NFS protocol version 4, > not with vers=3. > > I dumped the network traffic between NFS server and client2 > (I attached the dump). > > > Does anybody know what's happening and how to fix this issue? > > > Cheers, > Sascha -- 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
