On 03/12/2014 05:15 AM, Trond Myklebust wrote: > > On Mar 12, 2014, at 1:38, NeilBrown <neilb@xxxxxxx> wrote: > >> On Tue, 11 Mar 2014 10:52:36 -0400 Steve Dickson <SteveD@xxxxxxxxxx> wrote: >> >>> On 03/10/2014 06:01 PM, NeilBrown wrote: >>>> >>>> With a 3.11.10 client talking to a 3.2.0 server I run >>>> rpc.nfsd 0 >>>> rpc.nfsd -T -N4 >>>> on the server, then >>>> rpcinfo -p SERVER | grep nfs >>>> shows >>>> 100003 2 udp 2049 nfs >>>> 100003 3 udp 2049 nfs >>>> 100227 2 udp 2049 nfs_acl >>>> 100227 3 udp 2049 nfs_acl >>>> >>>> On client I run >>>> mount -v SERVER:/PATH /mnt >>>> and I get >>>> mount.nfs: trying text-based options 'vers=4,addr=192.168.1.3,clientaddr=192.168.1.2' >>>> mount.nfs: mount(2): Connection refused >>>> >>>> repeating ever 10 seconds or so. It eventually times out after 2 minutes. >>>> >>>> Same client to a 3.10 server I get the same behaviour. >>>> 3.2.0 client and 3.10 server, same behaviour again. >>>> >>>> I have noticed that sometimes when I stop the NFS server the registration >>>> with rpcbind doesn't go away. Not often, but sometimes. I wonder if that >>>> could be confusing something? Can you check that nfsv4 has been >>>> de-registered from rpcbind? >>>> >>>> I note you are getting the error: >>>> >>>>> mount.nfs: portmap query failed: RPC: Remote system error - Connection refused >>>> >>>> This seems to suggest that rpcbind isn't running. Yet when I kill rpcbind >>>> and try a v3 mount I get >>>> >>>> mount.nfs: portmap query failed: RPC: Unable to receive - Connection refused >>>> >>>> which is slightly different, so presumably there is a different cause in your >>>> case. >>>> >>>> Maybe you could turn on some rpcdebug tracing to see what is happening? >>> Ok... I had to dial back my client to an older kernel (3.12) >>> to start seeing what you were seeing... >>> >>> I would make one change and one comment... The change I would >>> like to make (I'll re-post it) is to ping the server to see >>> if v4 came up instead of asking rpcbind if its registered. >>> Code wise I think it cleaner and quicker plus I'm not sure >>> its a good idea to tie v4 and rpcbind together... >> >> My logic was that if rpcbind was running at all, then any v4 server should >> register with it. It would seem odd for rpcbind to report "v2 or v3" but for >> v4 to be running anyway. >> However I don't object in principle to your approach. >> I'll have a look at the code. >> >> >>> >>> My comment is this... This code become obsolete with the 3.13 >>> kernel because the kernel never returns the timeout or the >>> ECONNREFUSED... The mount just spins in the kernel until >>> interrupted. >> >> This sounds like a regression to me. For a systemcall that used to fail to >> now hang sounds like an API change, and we usually discourage those. >> >> Can it be fixed? Trond? > > Can someone please provide a test case that confirms that there has been such a change? On the server: rpc.nfsd 0 rpc.nfsd -N4 On the client mount <server>:/export /mnt I have a mount hanging/spinning since yesterday 19178 pts/2 D+ 0:26 /sbin/mount.nfs fedora:/home /mnt/home -v -o rw A stack dump from crash: PID: 19178 TASK: ffff8800ba2b41a0 CPU: 0 COMMAND: "mount.nfs" #0 [ffff8800b93115f8] __schedule at ffffffff815f0c3d #1 [ffff8800b9311660] schedule at ffffffff815f1179 #2 [ffff8800b9311670] rpc_wait_bit_killable at ffffffffa03f7a35 [sunrpc] #3 [ffff8800b9311688] __wait_on_bit at ffffffff815ef200 #4 [ffff8800b93116c8] out_of_line_wait_on_bit at ffffffff815ef2b7 #5 [ffff8800b9311738] __rpc_execute at ffffffffa03f890a [sunrpc] #6 [ffff8800b9311798] rpc_execute at ffffffffa03f9fce [sunrpc] #7 [ffff8800b93117c8] rpc_run_task at ffffffffa03f01c0 [sunrpc] #8 [ffff8800b93117e8] rpc_call_sync at ffffffffa03f0230 [sunrpc] #9 [ffff8800b9311840] nfs4_proc_setclientid at ffffffffa06c9c49 [nfsv4] #10 [ffff8800b9311988] nfs40_discover_server_trunking at ffffffffa06d8489 [nfsv4] #11 [ffff8800b93119d0] nfs4_discover_server_trunking at ffffffffa06daf2d [nfsv4] #12 [ffff8800b9311a28] nfs4_init_client at ffffffffa06e29a4 [nfsv4] #13 [ffff8800b9311b20] nfs_get_client at ffffffffa06816ba [nfs] #14 [ffff8800b9311b80] nfs4_set_client at ffffffffa06e1fb0 [nfsv4] #15 [ffff8800b9311c00] nfs4_create_server at ffffffffa06e34ce [nfsv4] #16 [ffff8800b9311c88] nfs4_remote_mount at ffffffffa06db90e [nfsv4] #17 [ffff8800b9311cb0] mount_fs at ffffffff811b3c89 #18 [ffff8800b9311cf8] vfs_kern_mount at ffffffff811cea8f #19 [ffff8800b9311d30] nfs_do_root_mount at ffffffffa06db836 [nfsv4] #20 [ffff8800b9311d70] nfs4_try_mount at ffffffffa06dbc24 [nfsv4] #21 [ffff8800b9311da0] nfs_fs_mount at ffffffffa068dcc5 [nfs] #22 [ffff8800b9311e28] mount_fs at ffffffff811b3c89 #23 [ffff8800b9311e70] vfs_kern_mount at ffffffff811cea8f #24 [ffff8800b9311ea8] do_mount at ffffffff811d0e3e #25 [ffff8800b9311f28] sys_mount at ffffffff811d16b6 #26 [ffff8800b9311f80] system_call_fastpath at ffffffff815fc0d9 > I would expect the timeouts to have changed due to the NFSv4 trunking detection (which is > exactly why it is wrong to rely on the kernel timeouts here anyway), but I would not expect > the kernel to never time out at all. It appears it started with 3.13 kernels... The above stack is from a 3.14-ish client. That patch I posted the other day fixed this by breaking out of the case statement with -ETIMEDOUT errors in nfs4_discover_server_trunking() instead of ssleep(1) and then trying the RPC.... steved. -- 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
