Merge commit 'linux-pnfs/nfs41-for-2.6.31' into nfsv41-for-2.6.31 (301933a0) · Commits · 戴 / test

fs/nfs/Kconfig

+9 −0

Original line number	Diff line number	Diff line
		@@ -74,6 +74,15 @@ config NFS_V4

		If unsure, say N.

		config NFS_V4_1
		bool "NFS client support for NFSv4.1 (DEVELOPER ONLY)"
		depends on NFS_V4 && EXPERIMENTAL
		help
		This option enables support for minor version 1 of the NFSv4 protocol
		(draft-ietf-nfsv4-minorversion1) in the kernel's NFS client.

		Unless you're an NFS developer, say N.

		config ROOT_NFS
		bool "Root file system on NFS"
		depends on NFS_FS=y && IP_PNP

fs/nfs/callback.c

+179 −35

Original line number	Diff line number	Diff line
		@@ -17,6 +17,9 @@
		#include <linux/freezer.h>
		#include <linux/kthread.h>
		#include <linux/sunrpc/svcauth_gss.h>
		#if defined(CONFIG_NFS_V4_1)
		#include <linux/sunrpc/bc_xprt.h>
		#endif

		#include <net/inet_sock.h>

		@@ -28,11 +31,12 @@

		struct nfs_callback_data {
		unsigned int users;
		struct svc_serv *serv;
		struct svc_rqst *rqst;
		struct task_struct *task;
		};

		static struct nfs_callback_data nfs_callback_info;
		static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
		static DEFINE_MUTEX(nfs_callback_mutex);
		static struct svc_program nfs4_callback_program;

		@@ -56,10 +60,10 @@ module_param_call(callback_tcpport, param_set_port, param_get_int,
		&nfs_callback_set_tcpport, 0644);

		/*
		* This is the callback kernel thread.
		* This is the NFSv4 callback kernel thread.
		*/
		static int
		nfs_callback_svc(void *vrqstp)
		nfs4_callback_svc(void *vrqstp)
		{
		int err, preverr = 0;
		struct svc_rqst *rqstp = vrqstp;
		@@ -97,20 +101,12 @@ nfs_callback_svc(void *vrqstp)
		}

		/*
		* Bring up the callback thread if it is not already up.
		* Prepare to bring up the NFSv4 callback service
		*/
		int nfs_callback_up(void)
		struct svc_rqst *
		nfs4_callback_up(struct svc_serv *serv)
		{
		struct svc_serv *serv = NULL;
		int ret = 0;

		mutex_lock(&nfs_callback_mutex);
		if (nfs_callback_info.users++ \|\| nfs_callback_info.task != NULL)
		goto out;
		serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
		ret = -ENOMEM;
		if (!serv)
		goto out_err;
		int ret;

		ret = svc_create_xprt(serv, "tcp", PF_INET,
		nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
		@@ -131,23 +127,168 @@ int nfs_callback_up(void)
		goto out_err;
		#endif /* defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE) */

		nfs_callback_info.rqst = svc_prepare_thread(serv, &serv->sv_pools[0]);
		if (IS_ERR(nfs_callback_info.rqst)) {
		ret = PTR_ERR(nfs_callback_info.rqst);
		nfs_callback_info.rqst = NULL;
		return svc_prepare_thread(serv, &serv->sv_pools[0]);

		out_err:
		if (ret == 0)
		ret = -ENOMEM;
		return ERR_PTR(ret);
		}

		#if defined(CONFIG_NFS_V4_1)
		/*
		* The callback service for NFSv4.1 callbacks
		*/
		static int
		nfs41_callback_svc(void *vrqstp)
		{
		struct svc_rqst *rqstp = vrqstp;
		struct svc_serv *serv = rqstp->rq_server;
		struct rpc_rqst *req;
		int error;
		DEFINE_WAIT(wq);

		set_freezable();

		/*
		* FIXME: do we really need to run this under the BKL? If so, please
		* add a comment about what it's intended to protect.
		*/
		lock_kernel();
		while (!kthread_should_stop()) {
		prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
		spin_lock_bh(&serv->sv_cb_lock);
		if (!list_empty(&serv->sv_cb_list)) {
		req = list_first_entry(&serv->sv_cb_list,
		struct rpc_rqst, rq_bc_list);
		list_del(&req->rq_bc_list);
		spin_unlock_bh(&serv->sv_cb_lock);
		dprintk("Invoking bc_svc_process()\n");
		error = bc_svc_process(serv, req, rqstp);
		dprintk("bc_svc_process() returned w/ error code= %d\n",
		error);
		} else {
		spin_unlock_bh(&serv->sv_cb_lock);
		schedule();
		}
		finish_wait(&serv->sv_cb_waitq, &wq);
		}
		unlock_kernel();
		return 0;
		}

		/*
		* Bring up the NFSv4.1 callback service
		*/
		struct svc_rqst *
		nfs41_callback_up(struct svc_serv serv, struct rpc_xprt xprt)
		{
		struct svc_xprt *bc_xprt;
		struct svc_rqst *rqstp = ERR_PTR(-ENOMEM);

		dprintk("--> %s\n", __func__);
		/* Create a svc_sock for the service */
		bc_xprt = svc_sock_create(serv, xprt->prot);
		if (!bc_xprt)
		goto out;

		/*
		* Save the svc_serv in the transport so that it can
		* be referenced when the session backchannel is initialized
		*/
		serv->bc_xprt = bc_xprt;
		xprt->bc_serv = serv;

		INIT_LIST_HEAD(&serv->sv_cb_list);
		spin_lock_init(&serv->sv_cb_lock);
		init_waitqueue_head(&serv->sv_cb_waitq);
		rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
		if (IS_ERR(rqstp))
		svc_sock_destroy(bc_xprt);
		out:
		dprintk("--> %s return %p\n", __func__, rqstp);
		return rqstp;
		}

		static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
		struct svc_serv serv, struct rpc_xprt xprt,
		struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
		{
		if (minorversion) {
		*rqstpp = nfs41_callback_up(serv, xprt);
		*callback_svc = nfs41_callback_svc;
		}
		return minorversion;
		}

		static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
		struct nfs_callback_data *cb_info)
		{
		if (minorversion)
		xprt->bc_serv = cb_info->serv;
		}
		#else
		static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
		struct svc_serv serv, struct rpc_xprt xprt,
		struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
		{
		return 0;
		}

		static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
		struct nfs_callback_data *cb_info)
		{
		}
		#endif /* CONFIG_NFS_V4_1 */

		/*
		* Bring up the callback thread if it is not already up.
		*/
		int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
		{
		struct svc_serv *serv = NULL;
		struct svc_rqst *rqstp;
		int (callback_svc)(void vrqstp);
		struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
		char svc_name[12];
		int ret = 0;
		int minorversion_setup;

		mutex_lock(&nfs_callback_mutex);
		if (cb_info->users++ \|\| cb_info->task != NULL) {
		nfs_callback_bc_serv(minorversion, xprt, cb_info);
		goto out;
		}
		serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
		if (!serv) {
		ret = -ENOMEM;
		goto out_err;
		}

		minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion,
		serv, xprt, &rqstp, &callback_svc);
		if (!minorversion_setup) {
		/* v4.0 callback setup */
		rqstp = nfs4_callback_up(serv);
		callback_svc = nfs4_callback_svc;
		}

		if (IS_ERR(rqstp)) {
		ret = PTR_ERR(rqstp);
		goto out_err;
		}

		svc_sock_update_bufs(serv);

		nfs_callback_info.task = kthread_run(nfs_callback_svc,
		nfs_callback_info.rqst,
		"nfsv4-svc");
		if (IS_ERR(nfs_callback_info.task)) {
		ret = PTR_ERR(nfs_callback_info.task);
		svc_exit_thread(nfs_callback_info.rqst);
		nfs_callback_info.rqst = NULL;
		nfs_callback_info.task = NULL;
		sprintf(svc_name, "nfsv4.%u-svc", minorversion);
		cb_info->serv = serv;
		cb_info->rqst = rqstp;
		cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
		if (IS_ERR(cb_info->task)) {
		ret = PTR_ERR(cb_info->task);
		svc_exit_thread(cb_info->rqst);
		cb_info->rqst = NULL;
		cb_info->task = NULL;
		goto out_err;
		}
		out:
		@@ -164,22 +305,25 @@ out:
		out_err:
		dprintk("NFS: Couldn't create callback socket or server thread; "
		"err = %d\n", ret);
		nfs_callback_info.users--;
		cb_info->users--;
		goto out;
		}

		/*
		* Kill the callback thread if it's no longer being used.
		*/
		void nfs_callback_down(void)
		void nfs_callback_down(int minorversion)
		{
		struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];

		mutex_lock(&nfs_callback_mutex);
		nfs_callback_info.users--;
		if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) {
		kthread_stop(nfs_callback_info.task);
		svc_exit_thread(nfs_callback_info.rqst);
		nfs_callback_info.rqst = NULL;
		nfs_callback_info.task = NULL;
		cb_info->users--;
		if (cb_info->users == 0 && cb_info->task != NULL) {
		kthread_stop(cb_info->task);
		svc_exit_thread(cb_info->rqst);
		cb_info->serv = NULL;
		cb_info->rqst = NULL;
		cb_info->task = NULL;
		}
		mutex_unlock(&nfs_callback_mutex);
		}

fs/nfs/callback.h

+61 −7

Original line number	Diff line number	Diff line
		@@ -20,13 +20,24 @@ enum nfs4_callback_procnum {
		enum nfs4_callback_opnum {
		OP_CB_GETATTR = 3,
		OP_CB_RECALL = 4,
		/* Callback operations new to NFSv4.1 */
		OP_CB_LAYOUTRECALL = 5,
		OP_CB_NOTIFY = 6,
		OP_CB_PUSH_DELEG = 7,
		OP_CB_RECALL_ANY = 8,
		OP_CB_RECALLABLE_OBJ_AVAIL = 9,
		OP_CB_RECALL_SLOT = 10,
		OP_CB_SEQUENCE = 11,
		OP_CB_WANTS_CANCELLED = 12,
		OP_CB_NOTIFY_LOCK = 13,
		OP_CB_NOTIFY_DEVICEID = 14,
		OP_CB_ILLEGAL = 10044,
		};

		struct cb_compound_hdr_arg {
		unsigned int taglen;
		const char *tag;
		unsigned int callback_ident;
		unsigned int minorversion;
		unsigned nops;
		};

		@@ -59,16 +70,59 @@ struct cb_recallargs {
		uint32_t truncate;
		};

		#if defined(CONFIG_NFS_V4_1)

		struct referring_call {
		uint32_t rc_sequenceid;
		uint32_t rc_slotid;
		};

		struct referring_call_list {
		struct nfs4_sessionid rcl_sessionid;
		uint32_t rcl_nrefcalls;
		struct referring_call *rcl_refcalls;
		};

		struct cb_sequenceargs {
		struct sockaddr *csa_addr;
		struct nfs4_sessionid csa_sessionid;
		uint32_t csa_sequenceid;
		uint32_t csa_slotid;
		uint32_t csa_highestslotid;
		uint32_t csa_cachethis;
		uint32_t csa_nrclists;
		struct referring_call_list *csa_rclists;
		};

		struct cb_sequenceres {
		__be32 csr_status;
		struct nfs4_sessionid csr_sessionid;
		uint32_t csr_sequenceid;
		uint32_t csr_slotid;
		uint32_t csr_highestslotid;
		uint32_t csr_target_highestslotid;
		};

		extern unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
		struct cb_sequenceres *res);

		#endif /* CONFIG_NFS_V4_1 */

		extern __be32 nfs4_callback_getattr(struct cb_getattrargs args, struct cb_getattrres res);
		extern __be32 nfs4_callback_recall(struct cb_recallargs args, void dummy);

		#ifdef CONFIG_NFS_V4
		extern int nfs_callback_up(void);
		extern void nfs_callback_down(void);
		#else
		#define nfs_callback_up() (0)
		#define nfs_callback_down() do {} while(0)
		#endif
		extern int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt);
		extern void nfs_callback_down(int minorversion);
		#endif /* CONFIG_NFS_V4 */

		/*
		* nfs41: Callbacks are expected to not cause substantial latency,
		* so we limit their concurrency to 1 by setting up the maximum number
		* of slots for the backchannel.
		*/
		#define NFS41_BC_MIN_CALLBACKS 1
		#define NFS41_BC_MAX_CALLBACKS 1

		extern unsigned int nfs_callback_set_tcpport;
		extern unsigned short nfs_callback_tcpport;

fs/nfs/callback_proc.c

+127 −0

Original line number	Diff line number	Diff line
		@@ -101,3 +101,130 @@ out:
		dprintk("%s: exit with status = %d\n", __func__, ntohl(res));
		return res;
		}

		#if defined(CONFIG_NFS_V4_1)

		/*
		* Validate the sequenceID sent by the server.
		* 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,
		* since we only currently implement idempotent callbacks anyway.
		*
		* We have a single slot backchannel at this time, so we don't bother
		* checking the used_slots bit array on the table. The lower layer guarantees
		* a single outstanding callback request at a time.
		*/
		static int
		validate_seqid(struct nfs4_slot_table *tbl, u32 slotid, u32 seqid)
		{
		struct nfs4_slot *slot;

		dprintk("%s enter. slotid %d seqid %d\n",
		__func__, slotid, seqid);

		if (slotid > NFS41_BC_MAX_CALLBACKS)
		return htonl(NFS4ERR_BADSLOT);

		slot = tbl->slots + slotid;
		dprintk("%s slot table seqid: %d\n", __func__, slot->seq_nr);

		/* Normal */
		if (likely(seqid == slot->seq_nr + 1)) {
		slot->seq_nr++;
		return htonl(NFS4_OK);
		}

		/* Replay */
		if (seqid == slot->seq_nr) {
		dprintk("%s seqid %d is a replay - no DRC available\n",
		__func__, seqid);
		return htonl(NFS4_OK);
		}

		/* Wraparound */
		if (seqid == 1 && (slot->seq_nr + 1) == 0) {
		slot->seq_nr = 1;
		return htonl(NFS4_OK);
		}

		/* Misordered request */
		return htonl(NFS4ERR_SEQ_MISORDERED);
		}

		/*
		* Returns a pointer to a held 'struct nfs_client' that matches the server's
		* address, major version number, and session ID. It is the caller's
		* responsibility to release the returned reference.
		*
		* Returns NULL if there are no connections with sessions, or if no session
		* matches the one of interest.
		*/
		static struct nfs_client *find_client_with_session(
		const struct sockaddr *addr, u32 nfsversion,
		struct nfs4_sessionid *sessionid)
		{
		struct nfs_client *clp;

		clp = nfs_find_client(addr, 4);
		if (clp == NULL)
		return NULL;

		do {
		struct nfs_client *prev = clp;

		if (clp->cl_session != NULL) {
		if (memcmp(clp->cl_session->sess_id.data,
		sessionid->data,
		NFS4_MAX_SESSIONID_LEN) == 0) {
		/* Returns a held reference to clp */
		return clp;
		}
		}
		clp = nfs_find_client_next(prev);
		nfs_put_client(prev);
		} while (clp != NULL);

		return NULL;
		}

		/* FIXME: referring calls should be processed */
		unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
		struct cb_sequenceres *res)
		{
		struct nfs_client *clp;
		int i, status;

		for (i = 0; i < args->csa_nrclists; i++)
		kfree(args->csa_rclists[i].rcl_refcalls);
		kfree(args->csa_rclists);

		status = htonl(NFS4ERR_BADSESSION);
		clp = find_client_with_session(args->csa_addr, 4, &args->csa_sessionid);
		if (clp == NULL)
		goto out;

		status = validate_seqid(&clp->cl_session->bc_slot_table,
		args->csa_slotid, args->csa_sequenceid);
		if (status)
		goto out_putclient;

		memcpy(&res->csr_sessionid, &args->csa_sessionid,
		sizeof(res->csr_sessionid));
		res->csr_sequenceid = args->csa_sequenceid;
		res->csr_slotid = args->csa_slotid;
		res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
		res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;

		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;
		}

		#endif /* CONFIG_NFS_V4_1 */

fs/nfs/callback_xdr.c

+258 −22

Original line number	Diff line number	Diff line
		@@ -20,6 +20,11 @@
		2 + 2 + 3 + 3)
		#define CB_OP_RECALL_RES_MAXSZ (CB_OP_HDR_RES_MAXSZ)

		#if defined(CONFIG_NFS_V4_1)
		#define CB_OP_SEQUENCE_RES_MAXSZ (CB_OP_HDR_RES_MAXSZ + \
		4 + 1 + 3)
		#endif /* CONFIG_NFS_V4_1 */

		#define NFSDBG_FACILITY NFSDBG_CALLBACK

		typedef __be32 (callback_process_op_t)(void , void *);
		@@ -132,7 +137,6 @@ static __be32 decode_stateid(struct xdr_stream xdr, nfs4_stateid stateid)
		static __be32 decode_compound_hdr_arg(struct xdr_stream xdr, struct cb_compound_hdr_arg hdr)
		{
		__be32 *p;
		unsigned int minor_version;
		__be32 status;

		status = decode_string(xdr, &hdr->taglen, &hdr->tag);
		@@ -147,15 +151,19 @@ static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound
		p = read_buf(xdr, 12);
		if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
		minor_version = ntohl(*p++);
		/* Check minor version is zero. */
		if (minor_version != 0) {
		printk(KERN_WARNING "%s: NFSv4 server callback with illegal minor version %u!\n",
		__func__, minor_version);
		hdr->minorversion = ntohl(*p++);
		/* Check minor version is zero or one. */
		if (hdr->minorversion <= 1) {
		p++; /* skip callback_ident */
		} else {
		printk(KERN_WARNING "%s: NFSv4 server callback with "
		"illegal minor version %u!\n",
		__func__, hdr->minorversion);
		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
		}
		hdr->callback_ident = ntohl(*p++);
		hdr->nops = ntohl(*p);
		dprintk("%s: minorversion %d nops %d\n", __func__,
		hdr->minorversion, hdr->nops);
		return 0;
		}

		@@ -204,6 +212,122 @@ out:
		return status;
		}

		#if defined(CONFIG_NFS_V4_1)

		static unsigned decode_sessionid(struct xdr_stream *xdr,
		struct nfs4_sessionid *sid)
		{
		uint32_t *p;
		int len = NFS4_MAX_SESSIONID_LEN;

		p = read_buf(xdr, len);
		if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);;

		memcpy(sid->data, p, len);
		return 0;
		}

		static unsigned decode_rc_list(struct xdr_stream *xdr,
		struct referring_call_list *rc_list)
		{
		uint32_t *p;
		int i;
		unsigned status;

		status = decode_sessionid(xdr, &rc_list->rcl_sessionid);
		if (status)
		goto out;

		status = htonl(NFS4ERR_RESOURCE);
		p = read_buf(xdr, sizeof(uint32_t));
		if (unlikely(p == NULL))
		goto out;

		rc_list->rcl_nrefcalls = ntohl(*p++);
		if (rc_list->rcl_nrefcalls) {
		p = read_buf(xdr,
		rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
		if (unlikely(p == NULL))
		goto out;
		rc_list->rcl_refcalls = kmalloc(rc_list->rcl_nrefcalls *
		sizeof(*rc_list->rcl_refcalls),
		GFP_KERNEL);
		if (unlikely(rc_list->rcl_refcalls == NULL))
		goto out;
		for (i = 0; i < rc_list->rcl_nrefcalls; i++) {
		rc_list->rcl_refcalls[i].rc_sequenceid = ntohl(*p++);
		rc_list->rcl_refcalls[i].rc_slotid = ntohl(*p++);
		}
		}
		status = 0;

		out:
		return status;
		}

		static unsigned decode_cb_sequence_args(struct svc_rqst *rqstp,
		struct xdr_stream *xdr,
		struct cb_sequenceargs *args)
		{
		uint32_t *p;
		int i;
		unsigned status;

		status = decode_sessionid(xdr, &args->csa_sessionid);
		if (status)
		goto out;

		status = htonl(NFS4ERR_RESOURCE);
		p = read_buf(xdr, 5 * sizeof(uint32_t));
		if (unlikely(p == NULL))
		goto out;

		args->csa_addr = svc_addr(rqstp);
		args->csa_sequenceid = ntohl(*p++);
		args->csa_slotid = ntohl(*p++);
		args->csa_highestslotid = ntohl(*p++);
		args->csa_cachethis = ntohl(*p++);
		args->csa_nrclists = ntohl(*p++);
		args->csa_rclists = NULL;
		if (args->csa_nrclists) {
		args->csa_rclists = kmalloc(args->csa_nrclists *
		sizeof(*args->csa_rclists),
		GFP_KERNEL);
		if (unlikely(args->csa_rclists == NULL))
		goto out;

		for (i = 0; i < args->csa_nrclists; i++) {
		status = decode_rc_list(xdr, &args->csa_rclists[i]);
		if (status)
		goto out_free;
		}
		}
		status = 0;

		dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u slotid %u "
		"highestslotid %u cachethis %d nrclists %u\n",
		__func__,
		((u32 *)&args->csa_sessionid)[0],
		((u32 *)&args->csa_sessionid)[1],
		((u32 *)&args->csa_sessionid)[2],
		((u32 *)&args->csa_sessionid)[3],
		args->csa_sequenceid, args->csa_slotid,
		args->csa_highestslotid, args->csa_cachethis,
		args->csa_nrclists);
		out:
		dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
		return status;

		out_free:
		for (i = 0; i < args->csa_nrclists; i++)
		kfree(args->csa_rclists[i].rcl_refcalls);
		kfree(args->csa_rclists);
		goto out;
		}

		#endif /* CONFIG_NFS_V4_1 */

		static __be32 encode_string(struct xdr_stream xdr, unsigned int len, const char str)
		{
		__be32 *p;
		@@ -353,31 +477,134 @@ out:
		return status;
		}

		static __be32 process_op(struct svc_rqst *rqstp,
		#if defined(CONFIG_NFS_V4_1)

		static unsigned encode_sessionid(struct xdr_stream *xdr,
		const struct nfs4_sessionid *sid)
		{
		uint32_t *p;
		int len = NFS4_MAX_SESSIONID_LEN;

		p = xdr_reserve_space(xdr, len);
		if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);

		memcpy(p, sid, len);
		return 0;
		}

		static unsigned encode_cb_sequence_res(struct svc_rqst *rqstp,
		struct xdr_stream *xdr,
		const struct cb_sequenceres *res)
		{
		uint32_t *p;
		unsigned status = res->csr_status;

		if (unlikely(status != 0))
		goto out;

		encode_sessionid(xdr, &res->csr_sessionid);

		p = xdr_reserve_space(xdr, 4 * sizeof(uint32_t));
		if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);

		*p++ = htonl(res->csr_sequenceid);
		*p++ = htonl(res->csr_slotid);
		*p++ = htonl(res->csr_highestslotid);
		*p++ = htonl(res->csr_target_highestslotid);
		out:
		dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
		return status;
		}

		static __be32
		preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
		{
		if (op_nr == OP_CB_SEQUENCE) {
		if (nop != 0)
		return htonl(NFS4ERR_SEQUENCE_POS);
		} else {
		if (nop == 0)
		return htonl(NFS4ERR_OP_NOT_IN_SESSION);
		}

		switch (op_nr) {
		case OP_CB_GETATTR:
		case OP_CB_RECALL:
		case OP_CB_SEQUENCE:
		*op = &callback_ops[op_nr];
		break;

		case OP_CB_LAYOUTRECALL:
		case OP_CB_NOTIFY_DEVICEID:
		case OP_CB_NOTIFY:
		case OP_CB_PUSH_DELEG:
		case OP_CB_RECALL_ANY:
		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);

		default:
		return htonl(NFS4ERR_OP_ILLEGAL);
		}

		return htonl(NFS_OK);
		}

		#else /* CONFIG_NFS_V4_1 */

		static __be32
		preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
		{
		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
		}

		#endif /* CONFIG_NFS_V4_1 */

		static __be32
		preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
		{
		switch (op_nr) {
		case OP_CB_GETATTR:
		case OP_CB_RECALL:
		*op = &callback_ops[op_nr];
		break;
		default:
		return htonl(NFS4ERR_OP_ILLEGAL);
		}

		return htonl(NFS_OK);
		}

		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 callback_op *op = &callback_ops[0];
		unsigned int op_nr = OP_CB_ILLEGAL;
		__be32 status = 0;
		__be32 status;
		long maxlen;
		__be32 res;

		dprintk("%s: start\n", __func__);
		status = decode_op_hdr(xdr_in, &op_nr);
		if (likely(status == 0)) {
		switch (op_nr) {
		case OP_CB_GETATTR:
		case OP_CB_RECALL:
		op = &callback_ops[op_nr];
		break;
		default:
		op_nr = OP_CB_ILLEGAL;
		op = &callback_ops[0];
		if (unlikely(status)) {
		status = htonl(NFS4ERR_OP_ILLEGAL);
		goto out;
		}
		}

		dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
		__func__, minorversion, nop, op_nr);

		status = minorversion ? preprocess_nfs41_op(nop, op_nr, &op) :
		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))
		@@ -425,7 +652,8 @@ 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(rqstp, &xdr_in, argp, &xdr_out, resp);
		status = process_op(hdr_arg.minorversion, nops,
		rqstp, &xdr_in, argp, &xdr_out, resp);
		nops++;
		}

		@@ -452,7 +680,15 @@ static struct callback_op callback_ops[] = {
		.process_op = (callback_process_op_t)nfs4_callback_recall,
		.decode_args = (callback_decode_arg_t)decode_recall_args,
		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
		}
		},
		#if defined(CONFIG_NFS_V4_1)
		[OP_CB_SEQUENCE] = {
		.process_op = (callback_process_op_t)nfs4_callback_sequence,
		.decode_args = (callback_decode_arg_t)decode_cb_sequence_args,
		.encode_res = (callback_encode_res_t)encode_cb_sequence_res,
		.res_maxsize = CB_OP_SEQUENCE_RES_MAXSZ,
		},
		#endif /* CONFIG_NFS_V4_1 */
		};

		/*

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