Hello, I'm trying to find out how NFSv4 client can get read delegation. I'm using separate RHEL6 machines (2.6.32-71.el6.x86_64) as server and client respectively. If I use pynfs, I can see server gives out read delegation. Basically pynfs sends these RPCs to server - open (create), open_confirm, open, open_confirm. On real NFS client, If I do 'cat <file>' twice, client does not get read delegation. - (nfs4state.c) - if (!cb_up || !sop->so_confirmed) goto out; - Here sop->so_confirmed is 0. If I open the existing file with O_RDONLY twice (i.e., open, not close it and open again), client sends open only once to server. - So here also sop->so_confirmed is 0. Delegation is not sent out. (I've added more debug messages shown in below.) 2011-09-23T22:41:44.642938+02:00 int002st001 kernel: NFSD: nfs4_open_delegation enter 2011-09-23T22:41:44.642942+02:00 int002st001 kernel: NFSD: nfs4_open_claim_null 2011-09-23T22:41:44.643853+02:00 int002st001 kernel: NFSD: cb_up=1, sop->so_confirmed=0 2011-09-23T22:41:44.643857+02:00 int002st001 kernel: NFSD: either callback is not up or not open confirmed 2011-09-23T22:41:44.643858+02:00 int002st001 kernel: NFSD: nfs4_open_delegation exit If I open the existing file with O_RDWR and then open it with O_RDONLY, I can see "sop->so_confirmed = 1", but setlease failed. - I think it is because there is writer on this file. 2011-09-23T11:23:28.116280+02:00 int002st001 kernel: NFSD: nfs4_open_delegation enter 2011-09-23T11:23:28.116717+02:00 int002st001 kernel: NFSD: nfs4_open_claim_null 2011-09-23T11:23:28.117879+02:00 int002st001 kernel: NFSD: cb_up=1, sop->so_confirmed=1 2011-09-23T11:23:28.117887+02:00 int002st001 kernel: NFSD alloc_init_deleg 2011-09-23T11:23:28.117889+02:00 int002st001 kernel: NFSD: setlease failed [-11], no delegation 2011-09-23T11:23:28.119101+02:00 int002st001 kernel: NFSD: close_delegation dp ffff88006ba05e60 2011-09-23T11:23:28.119109+02:00 int002st001 kernel: NFSD: freeing dp ffff88006ba05e60 2011-09-23T11:23:28.120050+02:00 int002st001 kernel: NFSD: nfs4_open_delegation exit What is missing here? I will appreciate any advice. Thank you. Regards, Sukwoo Kang -- 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
