On Tue, 2014-01-14 at 17:32 +0200, Boaz Harrosh wrote: > An NFS4ERR_RECALLCONFLICT is returned by server from a GET_LAYOUT > only when a Server Sent a RECALL do to that GET_LAYOUT, or > the RECALL and GET_LAYOUT crossed on the wire. > In any way this means we want to wait at most until in-flight IO > is finished and the RECALL can be satisfied. > > So a proper wait here is more like 1/10 of a second, not 15 seconds > like we have now. (We use NFS4_POLL_RETRY_MIN here) > > Current code totally craps out performance of very large files on > most pnfs-objects layouts, because of how the map changes when the > file has grown beyond a raid group. > > CC: Stable Tree <[email protected]> > Signed-off-by: Boaz Harrosh <[email protected]> > --- > fs/nfs/nfs4proc.c | 22 +++++++++++++++++++--- > 1 file changed, 19 insertions(+), 3 deletions(-) > > diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c > index d53d678..3264fca 100644 > --- a/fs/nfs/nfs4proc.c > +++ b/fs/nfs/nfs4proc.c > @@ -7058,7 +7058,7 @@ static void nfs4_layoutget_done(struct rpc_task *task, > void *calldata) > struct nfs4_state *state = NULL; > unsigned long timeo, giveup; > > - dprintk("--> %s\n", __func__); > + dprintk("--> %s tk_status => %d\n", __func__, task->tk_status); > > if (!nfs41_sequence_done(task, &lgp->res.seq_res)) > goto out; > @@ -7067,11 +7067,27 @@ static void nfs4_layoutget_done(struct rpc_task > *task, void *calldata) > case 0: > goto out; > case -NFS4ERR_LAYOUTTRYLATER: > + /* NFS4ERR_RECALLCONFLICT is always a minimal delay (conflict with > + * self) > + * TODO: NFS4ERR_LAYOUTTRYLATER is a conflict with another client > + * (or clients). What we should do is randomize a short delay like on a > + * network broadcast burst, and raise the random max every failure. > + * For now leave it stateless and do this polling. > + */ > case -NFS4ERR_RECALLCONFLICT: > timeo = rpc_get_timeout(task->tk_client); > giveup = lgp->args.timestamp + timeo; > - if (time_after(giveup, jiffies)) > - task->tk_status = -NFS4ERR_DELAY; > + if (time_after(giveup, jiffies)) { > + /* Do a minimum delay, We are actually waiting for our > + * own IO to finish (In most cases) > + */ > + dprintk("%s: NFS4ERR_RECALLCONFLICT waiting\n", > + __func__); > + rpc_delay(task, NFS4_POLL_RETRY_MIN); > + task->tk_status = 0; > + rpc_restart_call_prepare(task); > + goto out; /* Do not call nfs4_async_handle_error() */ > + } >
For the default mount option of 'timeo=600', and the default #define NFS4_POLL_RETRY_MIN==HZ/10, this means we can end up pounding the server with 600 LAYOUTGET requests within the space of 1 minute, before giving up. Is that reasonable? -- Trond Myklebust Linux NFS client maintainer -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
