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Commit 464ee9f9 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4.1: Ensure that the client tracks the server target_highest_slotid 



Dynamic slot allocation in NFSv4.1 depends on the client being able to
track the server's target value for the highest slotid in the
slot table.  See the reference in Section 2.10.6.1 of RFC5661.

To avoid ordering problems in the case where 2 SEQUENCE replies contain
conflicting updates to this target value, we also introduce a generation
counter, to track whether or not an RPC containing a SEQUENCE operation
was launched before or after the last update.

Also rename the nfs4_slot_table target_max_slots field to
'target_highest_slotid' to avoid confusion with a slot
table size or number of slots.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent f4af6e2a

fs/nfs/callback_proc.c

+1 −1
Original line number Diff line number Diff line
@@ -576,7 +576,7 @@ __be32 nfs4_callback_recallslot(struct cb_recallslotargs *args, void *dummy, 
	if (args->crsa_target_max_slots == fc_tbl->max_slots)

		goto out;



	fc_tbl->target_max_slots = args->crsa_target_max_slots;

	fc_tbl->target_highest_slotid = args->crsa_target_max_slots;

	nfs41_handle_recall_slot(cps->clp);

out:

	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));

fs/nfs/nfs4proc.c

+25 −0
Original line number Diff line number Diff line
@@ -488,6 +488,28 @@ static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res) 
	res->sr_slot = NULL;

}



/* Update the client's idea of target_highest_slotid */

static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,

		u32 target_highest_slotid)

{

	if (tbl->target_highest_slotid == target_highest_slotid)

		return;

	tbl->target_highest_slotid = target_highest_slotid;

	tbl->generation++;

}



static void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,

		struct nfs4_slot *slot,

		struct nfs4_sequence_res *res)

{

	spin_lock(&tbl->slot_tbl_lock);

	if (tbl->generation != slot->generation)

		goto out;

	nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);

out:

	spin_unlock(&tbl->slot_tbl_lock);

}



static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)

{

	struct nfs4_session *session;
@@ -522,6 +544,7 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res * 
		/* Check sequence flags */

		if (res->sr_status_flags != 0)

			nfs4_schedule_lease_recovery(clp);

		nfs41_update_target_slotid(slot->table, slot, res);

		break;

	case -NFS4ERR_DELAY:

		/* The server detected a resend of the RPC call and
@@ -583,6 +606,7 @@ static struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl) 
		tbl->highest_used_slotid = slotid;

	ret = &tbl->slots[slotid];

	ret->renewal_time = jiffies;

	ret->generation = tbl->generation;



out:

	dprintk("<-- %s used_slots=%04lx highest_used=%d slotid=%d \n",
@@ -5693,6 +5717,7 @@ static void nfs4_add_and_init_slots(struct nfs4_slot_table *tbl, 
		tbl->max_slots = max_slots;

	}

	tbl->highest_used_slotid = NFS4_NO_SLOT;

	tbl->target_highest_slotid = max_slots - 1;

	for (i = 0; i < tbl->max_slots; i++)

		tbl->slots[i].seq_nr = ivalue;

	spin_unlock(&tbl->slot_tbl_lock);

fs/nfs/nfs4state.c

+3 −4
Original line number Diff line number Diff line
@@ -2033,17 +2033,16 @@ static int nfs4_recall_slot(struct nfs_client *clp) 
		return 0;

	nfs4_begin_drain_session(clp);

	fc_tbl = &clp->cl_session->fc_slot_table;

	new = nfs4_alloc_slots(fc_tbl, fc_tbl->target_max_slots, GFP_NOFS);

	new = nfs4_alloc_slots(fc_tbl, fc_tbl->target_highest_slotid + 1, GFP_NOFS);

        if (!new)

		return -ENOMEM;



	spin_lock(&fc_tbl->slot_tbl_lock);

	for (i = 0; i < fc_tbl->target_max_slots; i++)

	for (i = 0; i <= fc_tbl->target_highest_slotid; i++)

		new[i].seq_nr = fc_tbl->slots[i].seq_nr;

	old = fc_tbl->slots;

	fc_tbl->slots = new;

	fc_tbl->max_slots = fc_tbl->target_max_slots;

	fc_tbl->target_max_slots = 0;

	fc_tbl->max_slots = fc_tbl->target_highest_slotid + 1;

	clp->cl_session->fc_attrs.max_reqs = fc_tbl->max_slots;

	spin_unlock(&fc_tbl->slot_tbl_lock);

fs/nfs/nfs4xdr.c

+2 −2
Original line number Diff line number Diff line
@@ -5552,8 +5552,8 @@ static int decode_sequence(struct xdr_stream *xdr, 
	}

	/* highest slot id - currently not processed */

	dummy = be32_to_cpup(p++);

	/* target highest slot id - currently not processed */

	dummy = be32_to_cpup(p++);

	/* target highest slot id */

	res->sr_target_highest_slotid = be32_to_cpup(p++);

	/* result flags */

	res->sr_status_flags = be32_to_cpup(p);

	status = 0;

include/linux/nfs_fs_sb.h

+3 −2
Original line number Diff line number Diff line
@@ -217,8 +217,9 @@ struct nfs4_slot_table { 
	u32		max_slots;		/* # slots in table */

	u32		highest_used_slotid;	/* sent to server on each SEQ.

						 * op for dynamic resizing */

	u32		target_max_slots;	/* Set by CB_RECALL_SLOT as

						 * the new max_slots */

	u32		target_highest_slotid;	/* Server max_slot target */

	unsigned long	generation;		/* Generation counter for

						   target_highest_slotid */

	struct completion complete;

};