Commit ed7e5423 authored by Boaz Harrosh's avatar Boaz Harrosh Committed by Trond Myklebust
Browse files

pnfs: Proper delay for NFS4ERR_RECALLCONFLICT in layout_get_done 



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. In case of a server bug we delay exponentially
longer on each retry.

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 into the next raid group.

[Stable: This will patch back to 3.9. If there are earlier still
 maintained trees, please tell me I'll send a patch]

CC: Stable Tree <stable@vger.kernel.org>
Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 471252cd

fs/nfs/nfs4proc.c

+30 −4
Original line number Diff line number Diff line
@@ -7409,9 +7409,9 @@ static void nfs4_layoutget_done(struct rpc_task *task, void *calldata) 
	struct nfs_server *server = NFS_SERVER(inode);

	struct pnfs_layout_hdr *lo;

	struct nfs4_state *state = NULL;

	unsigned long timeo, giveup;

	unsigned long timeo, now, 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;
@@ -7419,12 +7419,38 @@ static void nfs4_layoutget_done(struct rpc_task *task, void *calldata) 
	switch (task->tk_status) {

	case 0:

		goto out;

	/*

	 * NFS4ERR_LAYOUTTRYLATER is a conflict with another client

	 * (or clients) writing to the same RAID stripe

	 */

	case -NFS4ERR_LAYOUTTRYLATER:

	/*

	 * NFS4ERR_RECALLCONFLICT is when conflict with self (must recall

	 * existing layout before getting a new one).

	 */

	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;

		now = jiffies;

		if (time_after(giveup, now)) {

			unsigned long delay;



			/* Delay for:

			 * - Not less then NFS4_POLL_RETRY_MIN.

			 * - One last time a jiffie before we give up

			 * - exponential backoff (time_now minus start_attempt)

			 */

			delay = max_t(unsigned long, NFS4_POLL_RETRY_MIN,

				    min((giveup - now - 1),

					now - lgp->args.timestamp));



			dprintk("%s: NFS4ERR_RECALLCONFLICT waiting %lu\n",

				__func__, delay);

			rpc_delay(task, delay);

			task->tk_status = 0;

			rpc_restart_call_prepare(task);

			goto out; /* Do not call nfs4_async_handle_error() */

		}

		break;

	case -NFS4ERR_EXPIRED:

	case -NFS4ERR_BAD_STATEID:

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