[PATCH 0/7] nfs41: return correct errors on callback replays version 3

[PATCH 0/7] nfs41: return correct errors on callback replays version 3

[andros]

nfs41: return correct errors on callback replays version 3

Responded to Tronds comments, fixed bugs in cb_recall_slot, and
resize slot table on session reset.

The first three patches clean up callback processing
0001-nfs41-fix-wrong-error-on-callback-header-xdr-overflo.patch
0002-nfs41-directly-encode-back-channel-error.patch
0003-nfs41-remove-uneeded-checks-in-callback-processing.patch

These next two implement correct error returns for v4.1 callback replays.
Since our back channel has a ca_maxrequestsize_cached = 0, a replay with
cachethis set to true results in a NFS4ERR_TOO_BIG_TO_CACHE error.
This code is set up to do a real DRC.
A replay with cachethis set to false returns a NFS4ERR_RETRY_UNCACHED_REP
error.
0004-nfs41-prepare-for-back-channel-drc.patch
0005-nfs41-back-channel-drc-minimal-implementation.patch

ADDED:
0006-nfs41-implement-cb_recall_slot.patch
The fore channel session is drained, then the new highest_slot is set.

0007-nfs41-resize-slot-table-in-reset.patch
The slot table size is renegotiated on session reset.

TODO: The callback code currently returns NFS4ERR_RESOURCE on all xdr
overflows. This is correct for v4.0, incorrect for v4.1.

Testing:

Modified nfsv4.1 pynfs server tested cb_recall replays with the cb_sequence
cachethis set to False and to True.

Modified nfs4.1 pyNFS server sends CB_RECALL_SLOT call during the Connectathon
basic big file test which uses all available slots.

Connectathon tests pass.

-->Andy

[PATCH 1/7] nfs41: fix wrong error on callback header xdr overflow

[andros]

From: Andy Adamson <andros@netapp.com>

Set NFS4ERR_RESOURCE as CB_COMPOUND status and do not return an op on
decode_op_hdr or encode_op_hdr buffer overflow.

NFS4ERR_RESOURCE is correct for v4.0. Will fix the return for v4.1 along with
all the other NFS4ERR_RESOURCE errors in a later patch.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
 fs/nfs/callback_xdr.c |   28 ++++++++++++++++++----------
 1 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 8e1a251..6ae3278 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -28,6 +28,9 @@
 
 #define NFSDBG_FACILITY NFSDBG_CALLBACK
 
+/* Internal error code */
+#define NFS4ERR_RESOURCE_HDR	11050
+
 typedef __be32 (*callback_process_op_t)(void *, void *);
 typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
 typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
@@ -173,7 +176,7 @@ static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
 	__be32 *p;
 	p = read_buf(xdr, 4);
 	if (unlikely(p == NULL))
-		return htonl(NFS4ERR_RESOURCE);
+		return htonl(NFS4ERR_RESOURCE_HDR);
 	*op = ntohl(*p);
 	return 0;
 }
@@ -465,7 +468,7 @@ static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
 	
 	p = xdr_reserve_space(xdr, 8);
 	if (unlikely(p == NULL))
-		return htonl(NFS4ERR_RESOURCE);
+		return htonl(NFS4ERR_RESOURCE_HDR);
 	*p++ = htonl(op);
 	*p = res;
 	return 0;
@@ -605,17 +608,15 @@ static __be32 process_op(uint32_t minorversion, int nop,
 		struct xdr_stream *xdr_out, void *resp)
 {
 	struct callback_op *op = &callback_ops[0];
-	unsigned int op_nr = OP_CB_ILLEGAL;
+	unsigned int op_nr;
 	__be32 status;
 	long maxlen;
 	__be32 res;
 
 	dprintk("%s: start\n", __func__);
 	status = decode_op_hdr(xdr_in, &op_nr);
-	if (unlikely(status)) {
-		status = htonl(NFS4ERR_OP_ILLEGAL);
-		goto out;
-	}
+	if (unlikely(status))
+		return status;
 
 	dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
 		__func__, minorversion, nop, op_nr);
@@ -624,7 +625,7 @@ static __be32 process_op(uint32_t minorversion, int nop,
 				preprocess_nfs4_op(op_nr, &op);
 	if (status == htonl(NFS4ERR_OP_ILLEGAL))
 		op_nr = OP_CB_ILLEGAL;
-out:
+
 	maxlen = xdr_out->end - xdr_out->p;
 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
 		if (likely(status == 0 && op->decode_args != NULL))
@@ -635,8 +636,8 @@ out:
 		status = htonl(NFS4ERR_RESOURCE);
 
 	res = encode_op_hdr(xdr_out, op_nr, status);
-	if (status == 0)
-		status = res;
+	if (unlikely(res))
+		return res;
 	if (op->encode_res != NULL && status == 0)
 		status = op->encode_res(rqstp, xdr_out, resp);
 	dprintk("%s: done, status = %d\n", __func__, ntohl(status));
@@ -677,6 +678,13 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
 		nops++;
 	}
 
+	/* Buffer overflow in decode_ops_hdr or encode_ops_hdr. Return
+	* resource error in cb_compound status without returning op */
+	if (unlikely(status == htonl(NFS4ERR_RESOURCE_HDR))) {
+		status = htonl(NFS4ERR_RESOURCE);
+		nops--;
+	}
+
 	*hdr_res.status = status;
 	*hdr_res.nops = htonl(nops);
 	dprintk("%s: done, status = %u\n", __func__, ntohl(status));
-- 
1.6.5.2

[PATCH 2/7] nfs41: directly encode back channel error

[andros]

From: Andy Adamson <andros@netapp.com>

Skip all other processing when error is encountered.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
 fs/nfs/callback_xdr.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 6ae3278..d3e07f4 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -625,16 +625,19 @@ static __be32 process_op(uint32_t minorversion, int nop,
 				preprocess_nfs4_op(op_nr, &op);
 	if (status == htonl(NFS4ERR_OP_ILLEGAL))
 		op_nr = OP_CB_ILLEGAL;
+	if (status)
+		goto encode_hdr;
 
 	maxlen = xdr_out->end - xdr_out->p;
 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
-		if (likely(status == 0 && op->decode_args != NULL))
+		if (likely(op->decode_args != NULL))
 			status = op->decode_args(rqstp, xdr_in, argp);
 		if (likely(status == 0 && op->process_op != NULL))
 			status = op->process_op(argp, resp);
 	} else
 		status = htonl(NFS4ERR_RESOURCE);
 
+encode_hdr:
 	res = encode_op_hdr(xdr_out, op_nr, status);
 	if (unlikely(res))
 		return res;
-- 
1.6.5.2

[PATCH 3/7] nfs41: remove uneeded checks in callback processing

[andros]

From: Andy Adamson <andros@netapp.com>

All callback operations have arguments to decode and require processing.
The preprocess_nfs4X_op functions catch unsupported or illegal ops so
decode_args and process_op pointers are always non NULL.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
 fs/nfs/callback_xdr.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index d3e07f4..a6f2ded 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -630,9 +630,8 @@ static __be32 process_op(uint32_t minorversion, int nop,
 
 	maxlen = xdr_out->end - xdr_out->p;
 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
-		if (likely(op->decode_args != NULL))
-			status = op->decode_args(rqstp, xdr_in, argp);
-		if (likely(status == 0 && op->process_op != NULL))
+		status = op->decode_args(rqstp, xdr_in, argp);
+		if (likely(status == 0))
 			status = op->process_op(argp, resp);
 	} else
 		status = htonl(NFS4ERR_RESOURCE);
-- 
1.6.5.2

[PATCH 4/7] nfs41: prepare for back channel drc

[andros]

From: Andy Adamson <andros@netapp.com>

Make all cb_sequence arguments available to verify_seqid which will make
replay decisions.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
 fs/nfs/callback_proc.c |   19 +++++++++----------
 1 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index defa9b4..7f92b6d 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -153,34 +153,34 @@ int nfs41_validate_delegation_stateid(struct nfs_delegation *delegation, const n
  * a single outstanding callback request at a time.
  */
 static int
-validate_seqid(struct nfs4_slot_table *tbl, u32 slotid, u32 seqid)
+validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
 {
 	struct nfs4_slot *slot;
 
 	dprintk("%s enter. slotid %d seqid %d\n",
-		__func__, slotid, seqid);
+		__func__, args->csa_slotid, args->csa_sequenceid);
 
-	if (slotid > NFS41_BC_MAX_CALLBACKS)
+	if (args->csa_slotid > NFS41_BC_MAX_CALLBACKS)
 		return htonl(NFS4ERR_BADSLOT);
 
-	slot = tbl->slots + slotid;
+	slot = tbl->slots + args->csa_slotid;
 	dprintk("%s slot table seqid: %d\n", __func__, slot->seq_nr);
 
 	/* Normal */
-	if (likely(seqid == slot->seq_nr + 1)) {
+	if (likely(args->csa_sequenceid == slot->seq_nr + 1)) {
 		slot->seq_nr++;
 		return htonl(NFS4_OK);
 	}
 
 	/* Replay */
-	if (seqid == slot->seq_nr) {
+	if (args->csa_sequenceid == slot->seq_nr) {
 		dprintk("%s seqid %d is a replay - no DRC available\n",
-			__func__, seqid);
+			__func__, args->csa_sequenceid);
 		return htonl(NFS4_OK);
 	}
 
 	/* Wraparound */
-	if (seqid == 1 && (slot->seq_nr + 1) == 0) {
+	if (args->csa_sequenceid == 1 && (slot->seq_nr + 1) == 0) {
 		slot->seq_nr = 1;
 		return htonl(NFS4_OK);
 	}
@@ -241,8 +241,7 @@ unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
 	if (clp == NULL)
 		goto out;
 
-	status = validate_seqid(&clp->cl_session->bc_slot_table,
-				args->csa_slotid, args->csa_sequenceid);
+	status = validate_seqid(&clp->cl_session->bc_slot_table, args);
 	if (status)
 		goto out_putclient;
 
-- 
1.6.5.2

[PATCH 5/7] nfs41: back channel drc minimal implementation

[andros]

From: Andy Adamson <andros@netapp.com>

For now the back channel ca_maxresponsesize_cached is 0 and there is no
backchannel DRC. Return NFS4ERR_REP_TOO_BIG_TO_CACHE when a cb_sequence
cachethis is true.  When it is false, return NFS4ERR_RETRY_UNCACHED_REP as the
next operation error.

Remember the replay error accross compound operation processing.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
 fs/nfs/callback_proc.c |   25 +++++++++++++++++--------
 fs/nfs/callback_xdr.c  |   19 +++++++++++++++----
 2 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 7f92b6d..3cc2333 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -143,9 +143,8 @@ int nfs41_validate_delegation_stateid(struct nfs_delegation *delegation, const n
  * Return success if the sequenceID is one more than what we last saw on
  * this slot, accounting for wraparound.  Increments the slot's sequence.
  *
- * We don't yet implement a duplicate request cache, so at this time
- * we will log replays, and process them as if we had not seen them before,
- * but we don't bump the sequence in the slot.  Not too worried about it,
+ * We don't yet implement a duplicate request cache, instead we set the
+ * back channel ca_maxresponsesize_cached to zero. This is OK for now
  * since we only currently implement idempotent callbacks anyway.
  *
  * We have a single slot backchannel at this time, so we don't bother
@@ -174,9 +173,15 @@ validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
 
 	/* Replay */
 	if (args->csa_sequenceid == slot->seq_nr) {
-		dprintk("%s seqid %d is a replay - no DRC available\n",
+		dprintk("%s seqid %d is a replay\n",
 			__func__, args->csa_sequenceid);
-		return htonl(NFS4_OK);
+		/* Signal process_op to set this error on next op */
+		if (args->csa_cachethis == 0)
+			return htonl(NFS4ERR_RETRY_UNCACHED_REP);
+
+		/* The ca_maxresponsesize_cached is 0 with no DRC */
+		else if (args->csa_cachethis == 1)
+			return htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
 	}
 
 	/* Wraparound */
@@ -255,9 +260,13 @@ unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
 out_putclient:
 	nfs_put_client(clp);
 out:
-	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
-	res->csr_status = status;
-	return res->csr_status;
+	if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP))
+		res->csr_status = 0;
+	else
+		res->csr_status = status;
+	dprintk("%s: exit with status = %d res->csr_status %d\n", __func__,
+		ntohl(status), ntohl(res->csr_status));
+	return status;
 }
 
 unsigned nfs4_callback_recallany(struct cb_recallanyargs *args, void *dummy)
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index a6f2ded..08b430d 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -605,7 +605,7 @@ preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
 static __be32 process_op(uint32_t minorversion, int nop,
 		struct svc_rqst *rqstp,
 		struct xdr_stream *xdr_in, void *argp,
-		struct xdr_stream *xdr_out, void *resp)
+		struct xdr_stream *xdr_out, void *resp, int* drc_status)
 {
 	struct callback_op *op = &callback_ops[0];
 	unsigned int op_nr;
@@ -628,6 +628,11 @@ static __be32 process_op(uint32_t minorversion, int nop,
 	if (status)
 		goto encode_hdr;
 
+	if (*drc_status) {
+		status = *drc_status;
+		goto encode_hdr;
+	}
+
 	maxlen = xdr_out->end - xdr_out->p;
 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
 		status = op->decode_args(rqstp, xdr_in, argp);
@@ -636,6 +641,12 @@ static __be32 process_op(uint32_t minorversion, int nop,
 	} else
 		status = htonl(NFS4ERR_RESOURCE);
 
+	/* Only set by OP_CB_SEQUENCE processing */
+	if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
+		*drc_status = status;
+		status = 0;
+	}
+
 encode_hdr:
 	res = encode_op_hdr(xdr_out, op_nr, status);
 	if (unlikely(res))
@@ -655,7 +666,7 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
 	struct cb_compound_hdr_res hdr_res = { NULL };
 	struct xdr_stream xdr_in, xdr_out;
 	__be32 *p;
-	__be32 status;
+	__be32 status, drc_status = 0;
 	unsigned int nops = 0;
 
 	dprintk("%s: start\n", __func__);
@@ -675,8 +686,8 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
 		return rpc_system_err;
 
 	while (status == 0 && nops != hdr_arg.nops) {
-		status = process_op(hdr_arg.minorversion, nops,
-				    rqstp, &xdr_in, argp, &xdr_out, resp);
+		status = process_op(hdr_arg.minorversion, nops, rqstp,
+				    &xdr_in, argp, &xdr_out, resp, &drc_status);
 		nops++;
 	}
 
-- 
1.6.5.2

[PATCH 6/7] nfs41: implement cb_recall_slot

[andros]

From: Andy Adamson <andros@netapp.com>

Drain the fore channel and reset the max_slots to the new value.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
 fs/nfs/callback.h         |    8 ++++++++
 fs/nfs/callback_proc.c    |   32 ++++++++++++++++++++++++++++++++
 fs/nfs/callback_xdr.c     |   22 +++++++++++++++++++++-
 fs/nfs/nfs4_fs.h          |    2 ++
 fs/nfs/nfs4state.c        |   43 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/nfs_fs_sb.h |    2 ++
 6 files changed, 108 insertions(+), 1 deletions(-)

diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
index d4036be..85a7cfd 100644
--- a/fs/nfs/callback.h
+++ b/fs/nfs/callback.h
@@ -119,6 +119,14 @@ struct cb_recallanyargs {
 };
 
 extern unsigned nfs4_callback_recallany(struct cb_recallanyargs *args, void *dummy);
+
+struct cb_recallslotargs {
+	struct sockaddr	*crsa_addr;
+	uint32_t	crsa_target_max_slots;
+};
+extern unsigned nfs4_callback_recallslot(struct cb_recallslotargs *args,
+					  void *dummy);
+
 #endif /* CONFIG_NFS_V4_1 */
 
 extern __be32 nfs4_callback_getattr(struct cb_getattrargs *args, struct cb_getattrres *res);
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 3cc2333..9318340 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -297,4 +297,36 @@ out:
 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
 	return status;
 }
+
+/* Reduce the fore channel's max_slots to the target value */
+unsigned nfs4_callback_recallslot(struct cb_recallslotargs *args, void *dummy)
+{
+	struct nfs_client *clp;
+	struct nfs4_slot_table *fc_tbl;
+	int status;
+
+	status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
+	clp = nfs_find_client(args->crsa_addr, 4);
+	if (clp == NULL)
+		goto out;
+
+	dprintk("NFS: CB_RECALL_SLOT request from %s target max slots %d\n",
+		rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR),
+		args->crsa_target_max_slots);
+
+	fc_tbl = &clp->cl_session->fc_slot_table;
+
+	status = htonl(NFS4ERR_BAD_HIGH_SLOT);
+	if (args->crsa_target_max_slots >= fc_tbl->max_slots ||
+	    args->crsa_target_max_slots < 1)
+		goto out;
+
+	fc_tbl->target_max_slots = args->crsa_target_max_slots;
+	nfs41_handle_recall_slot(clp);
+	status = htonl(NFS4_OK);
+	nfs_put_client(clp);	/* balance nfs_find_client */
+out:
+	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
+	return status;
+}
 #endif /* CONFIG_NFS_V4_1 */
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 08b430d..8e66e20 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -24,6 +24,7 @@
 #define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
 					4 + 1 + 3)
 #define CB_OP_RECALLANY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
+#define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
 #endif /* CONFIG_NFS_V4_1 */
 
 #define NFSDBG_FACILITY NFSDBG_CALLBACK
@@ -349,6 +350,20 @@ static unsigned decode_recallany_args(struct svc_rqst *rqstp,
 	return 0;
 }
 
+static unsigned decode_recallslot_args(struct svc_rqst *rqstp,
+					struct xdr_stream *xdr,
+					struct cb_recallslotargs *args)
+{
+	__be32 *p;
+
+	args->crsa_addr = svc_addr(rqstp);
+	p = read_buf(xdr, 4);
+	if (unlikely(p == NULL))
+		return htonl(NFS4ERR_BADXDR);
+	args->crsa_target_max_slots = ntohl(*p++);
+	return 0;
+}
+
 #endif /* CONFIG_NFS_V4_1 */
 
 static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
@@ -557,6 +572,7 @@ preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
 	case OP_CB_RECALL:
 	case OP_CB_SEQUENCE:
 	case OP_CB_RECALL_ANY:
+	case OP_CB_RECALL_SLOT:
 		*op = &callback_ops[op_nr];
 		break;
 
@@ -565,7 +581,6 @@ preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
 	case OP_CB_NOTIFY:
 	case OP_CB_PUSH_DELEG:
 	case OP_CB_RECALLABLE_OBJ_AVAIL:
-	case OP_CB_RECALL_SLOT:
 	case OP_CB_WANTS_CANCELLED:
 	case OP_CB_NOTIFY_LOCK:
 		return htonl(NFS4ERR_NOTSUPP);
@@ -734,6 +749,11 @@ static struct callback_op callback_ops[] = {
 		.decode_args = (callback_decode_arg_t)decode_recallany_args,
 		.res_maxsize = CB_OP_RECALLANY_RES_MAXSZ,
 	},
+	[OP_CB_RECALL_SLOT] = {
+		.process_op = (callback_process_op_t)nfs4_callback_recallslot,
+		.decode_args = (callback_decode_arg_t)decode_recallslot_args,
+		.res_maxsize = CB_OP_RECALLSLOT_RES_MAXSZ,
+	},
 #endif /* CONFIG_NFS_V4_1 */
 };
 
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 865265b..cd93dfc 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -46,6 +46,7 @@ enum nfs4_client_state {
 	NFS4CLNT_DELEGRETURN,
 	NFS4CLNT_SESSION_RESET,
 	NFS4CLNT_SESSION_DRAINING,
+	NFS4CLNT_RECALL_SLOT,
 };
 
 /*
@@ -278,6 +279,7 @@ extern void nfs4_schedule_state_recovery(struct nfs_client *);
 extern void nfs4_schedule_state_manager(struct nfs_client *);
 extern int nfs4_state_mark_reclaim_nograce(struct nfs_client *clp, struct nfs4_state *state);
 extern void nfs41_handle_sequence_flag_errors(struct nfs_client *clp, u32 flags);
+extern void nfs41_handle_recall_slot(struct nfs_client *clp);
 extern void nfs4_put_lock_state(struct nfs4_lock_state *lsp);
 extern int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl);
 extern void nfs4_copy_stateid(nfs4_stateid *, struct nfs4_state *, fl_owner_t);
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 6d263ed..df03355 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1249,6 +1249,12 @@ static int nfs4_reclaim_lease(struct nfs_client *clp)
 }
 
 #ifdef CONFIG_NFS_V4_1
+void nfs41_handle_recall_slot(struct nfs_client *clp)
+{
+	set_bit(NFS4CLNT_RECALL_SLOT, &clp->cl_state);
+	nfs4_schedule_state_recovery(clp);
+}
+
 void nfs41_handle_sequence_flag_errors(struct nfs_client *clp, u32 flags)
 {
 	if (!flags)
@@ -1299,6 +1305,34 @@ out:
 	return status;
 }
 
+static int nfs4_recall_slot(struct nfs_client *clp)
+{
+	struct nfs4_slot_table *fc_tbl = &clp->cl_session->fc_slot_table;
+	struct nfs4_channel_attrs *fc_attrs = &clp->cl_session->fc_attrs;
+	struct nfs4_slot *new, *old;
+	int i;
+
+	nfs4_begin_drain_session(clp);
+	new = kmalloc(fc_tbl->target_max_slots * sizeof(struct nfs4_slot),
+		      GFP_KERNEL);
+        if (!new)
+		return -ENOMEM;
+
+	spin_lock(&fc_tbl->slot_tbl_lock);
+	for (i = 0; i < fc_tbl->target_max_slots; 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_attrs->max_reqs = fc_tbl->max_slots;
+	spin_unlock(&fc_tbl->slot_tbl_lock);
+
+	kfree(old);
+	nfs4_end_drain_session(clp);
+	return 0;
+}
+
 #else /* CONFIG_NFS_V4_1 */
 static int nfs4_reset_session(struct nfs_client *clp) { return 0; }
 static int nfs4_end_drain_session(struct nfs_client *clp) { return 0; }
@@ -1397,6 +1431,15 @@ static void nfs4_state_manager(struct nfs_client *clp)
 			nfs_client_return_marked_delegations(clp);
 			continue;
 		}
+		/* Recall session slots */
+		if (test_and_clear_bit(NFS4CLNT_RECALL_SLOT, &clp->cl_state)
+		   && nfs4_has_session(clp)) {
+			status = nfs4_recall_slot(clp);
+			if (status < 0)
+				goto out_error;
+			continue;
+		}
+
 
 		nfs4_clear_state_manager_bit(clp);
 		/* Did we race with an attempt to give us more work? */
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 34fc6be..ecd9e6c 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -193,6 +193,8 @@ struct nfs4_slot_table {
 	int		max_slots;		/* # slots in table */
 	int		highest_used_slotid;	/* sent to server on each SEQ.
 						 * op for dynamic resizing */
+	int		target_max_slots;	/* Set by CB_RECALL_SLOT as
+						 * the new max_slots */
 };
 
 static inline int slot_idx(struct nfs4_slot_table *tbl, struct nfs4_slot *sp)
-- 
1.6.5.2

[PATCH 7/7] nfs41: resize slot table in reset

[andros]

From: Andy Adamson <andros@netapp.com>

When session is reset, client can renegotiate slot table size.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
 fs/nfs/nfs4proc.c |   40 +++++++++++++++++++++-------------------
 1 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 198d51d..eabe09e 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4573,26 +4573,32 @@ int nfs4_proc_get_lease_time(struct nfs_client *clp, struct nfs_fsinfo *fsinfo)
 /*
  * Reset a slot table
  */
-static int nfs4_reset_slot_table(struct nfs4_slot_table *tbl, int max_slots,
-		int old_max_slots, int ivalue)
+static int nfs4_reset_slot_table(struct nfs4_slot_table *tbl, u32 max_reqs,
+				 int ivalue)
 {
+	struct nfs4_slot *new = NULL;
 	int i;
 	int ret = 0;
 
-	dprintk("--> %s: max_reqs=%u, tbl %p\n", __func__, max_slots, tbl);
+	dprintk("--> %s: max_reqs=%u, tbl->max_slots %d\n", __func__,
+		max_reqs, tbl->max_slots);
 
-	/*
-	 * Until we have dynamic slot table adjustment, insist
-	 * upon the same slot table size
-	 */
-	if (max_slots != old_max_slots) {
-		dprintk("%s reset slot table does't match old\n",
-			__func__);
-		ret = -EINVAL; /*XXX NFS4ERR_REQ_TOO_BIG ? */
-		goto out;
+	/* Does the newly negotiated max_reqs match the existing slot table? */
+	if (max_reqs != tbl->max_slots) {
+		ret = -ENOMEM;
+		new = kmalloc(max_reqs * sizeof(struct nfs4_slot),
+			      GFP_KERNEL);
+		if (!new)
+			goto out;
+		ret = 0;
+		kfree(tbl->slots);
 	}
 	spin_lock(&tbl->slot_tbl_lock);
-	for (i = 0; i < max_slots; ++i)
+	if (new) {
+		tbl->slots = new;
+		tbl->max_slots = max_reqs;
+	}
+	for (i = 0; i < tbl->max_slots; ++i)
 		tbl->slots[i].seq_nr = ivalue;
 	spin_unlock(&tbl->slot_tbl_lock);
 	dprintk("%s: tbl=%p slots=%p max_slots=%d\n", __func__,
@@ -4610,16 +4616,12 @@ static int nfs4_reset_slot_tables(struct nfs4_session *session)
 	int status;
 
 	status = nfs4_reset_slot_table(&session->fc_slot_table,
-			session->fc_attrs.max_reqs,
-			session->fc_slot_table.max_slots,
-			1);
+			session->fc_attrs.max_reqs, 1);
 	if (status)
 		return status;
 
 	status = nfs4_reset_slot_table(&session->bc_slot_table,
-			session->bc_attrs.max_reqs,
-			session->bc_slot_table.max_slots,
-			0);
+			session->bc_attrs.max_reqs, 0);
 	return status;
 }
 
-- 
1.6.5.2

Re: [PATCH 6/7] nfs41: implement cb_recall_slot

[Trond Myklebust]

On Thu, 2010-01-14 at 17:45 -0500, andros@netapp.com wrote:=20
> From: Andy Adamson <andros@netapp.com>
>=20
> Drain the fore channel and reset the max_slots to the new value.
>=20
> Signed-off-by: Andy Adamson <andros@netapp.com>
> ---
>  fs/nfs/callback.h         |    8 ++++++++
>  fs/nfs/callback_proc.c    |   32 ++++++++++++++++++++++++++++++++
>  fs/nfs/callback_xdr.c     |   22 +++++++++++++++++++++-
>  fs/nfs/nfs4_fs.h          |    2 ++
>  fs/nfs/nfs4state.c        |   43 +++++++++++++++++++++++++++++++++++=
++++++++
>  include/linux/nfs_fs_sb.h |    2 ++
>  6 files changed, 108 insertions(+), 1 deletions(-)

  CC [M]  fs/nfs/nfs4state.o
/home/trondmy/devel/linux/linux_nfs-2.6/fs/nfs/nfs4state.c: In function
=E2=80=98nfs4_state_manager=E2=80=99:
/home/trondmy/devel/linux/linux_nfs-2.6/fs/nfs/nfs4state.c:1437: error:
implicit declaration of function =E2=80=98nfs4_recall_slot=E2=80=99
make[2]: *** [fs/nfs/nfs4state.o] Error 1
make[1]: *** [fs/nfs/nfs4state.o] Error 2
make: *** [sub-make] Error 2

Does not compile without CONFIG_NFS_V4_1

Trond