fs/nfs/callback_proc.c - kernel/msm-4.9 - Gitiles

 /*
  * linux/fs/nfs/callback_proc.c
  *
  * Copyright (C) 2004 Trond Myklebust
  *
  * NFSv4 callback procedures
  */
 #include <linux/nfs4.h>
 #include <linux/nfs_fs.h>
 #include <linux/slab.h>
 #include <linux/rcupdate.h>
 #include "nfs4_fs.h"
 #include "callback.h"
 #include "delegation.h"
 #include "internal.h"
 #include "pnfs.h"
 #include "nfs4session.h"

 #ifdef NFS_DEBUG
 #define NFSDBG_FACILITY NFSDBG_CALLBACK
 #endif

 __be32 nfs4_callback_getattr(struct cb_getattrargs *args,
 			     struct cb_getattrres *res,
 			     struct cb_process_state *cps)
 {
 	struct nfs_delegation *delegation;
 	struct nfs_inode *nfsi;
 	struct inode *inode;

 	res->status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
 	if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
 		goto out;

 	res->bitmap[0] = res->bitmap[1] = 0;
 	res->status = htonl(NFS4ERR_BADHANDLE);

 	dprintk_rcu("NFS: GETATTR callback request from %s\n",
 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));

 	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
 	if (inode == NULL)
 		goto out;
 	nfsi = NFS_I(inode);
 	rcu_read_lock();
 	delegation = rcu_dereference(nfsi->delegation);
 	if (delegation == NULL || (delegation->type & FMODE_WRITE) == 0)
 		goto out_iput;
 	res->size = i_size_read(inode);
 	res->change_attr = delegation->change_attr;
 	if (nfsi->npages != 0)
 		res->change_attr++;
 	res->ctime = inode->i_ctime;
 	res->mtime = inode->i_mtime;
 	res->bitmap[0] = (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE) &
 		args->bitmap[0];
 	res->bitmap[1] = (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY) &
 		args->bitmap[1];
 	res->status = 0;
 out_iput:
 	rcu_read_unlock();
 	iput(inode);
 out:
 	dprintk("%s: exit with status = %d\n", __func__, ntohl(res->status));
 	return res->status;
 }

 __be32 nfs4_callback_recall(struct cb_recallargs *args, void *dummy,
 			    struct cb_process_state *cps)
 {
 	struct inode *inode;
 	__be32 res;

 	res = htonl(NFS4ERR_OP_NOT_IN_SESSION);
 	if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
 		goto out;

 	dprintk_rcu("NFS: RECALL callback request from %s\n",
 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));

 	res = htonl(NFS4ERR_BADHANDLE);
 	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
 	if (inode == NULL)
 		goto out;
 	/* Set up a helper thread to actually return the delegation */
 	switch (nfs_async_inode_return_delegation(inode, &args->stateid)) {
 	case 0:
 		res = 0;
 		break;
 	case -ENOENT:
 		res = htonl(NFS4ERR_BAD_STATEID);
 		break;
 	default:
 		res = htonl(NFS4ERR_RESOURCE);
 	}
 	iput(inode);
 out:
 	dprintk("%s: exit with status = %d\n", __func__, ntohl(res));
 	return res;
 }

 #if defined(CONFIG_NFS_V4_1)

 /*
  * Lookup a layout by filehandle.
  *
  * Note: gets a refcount on the layout hdr and on its respective inode.
  * Caller must put the layout hdr and the inode.
  *
  * TODO: keep track of all layouts (and delegations) in a hash table
  * hashed by filehandle.
  */
 static struct pnfs_layout_hdr * get_layout_by_fh_locked(struct nfs_client *clp, struct nfs_fh *fh)
 {
 	struct nfs_server *server;
 	struct inode *ino;
 	struct pnfs_layout_hdr *lo;

 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		list_for_each_entry(lo, &server->layouts, plh_layouts) {
 			if (nfs_compare_fh(fh, &NFS_I(lo->plh_inode)->fh))
 				continue;
 			ino = igrab(lo->plh_inode);
 			if (!ino)
 				continue;
 			spin_lock(&ino->i_lock);
 			/* Is this layout in the process of being freed? */
 			if (NFS_I(ino)->layout != lo) {
 				spin_unlock(&ino->i_lock);
 				iput(ino);
 				continue;
 			}
 			pnfs_get_layout_hdr(lo);
 			spin_unlock(&ino->i_lock);
 			return lo;
 		}
 	}

 	return NULL;
 }

 static struct pnfs_layout_hdr * get_layout_by_fh(struct nfs_client *clp, struct nfs_fh *fh)
 {
 	struct pnfs_layout_hdr *lo;

 	spin_lock(&clp->cl_lock);
 	rcu_read_lock();
 	lo = get_layout_by_fh_locked(clp, fh);
 	rcu_read_unlock();
 	spin_unlock(&clp->cl_lock);

 	return lo;
 }

 static u32 initiate_file_draining(struct nfs_client *clp,
 				  struct cb_layoutrecallargs *args)
 {
 	struct inode *ino;
 	struct pnfs_layout_hdr *lo;
 	u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
 	LIST_HEAD(free_me_list);

 	lo = get_layout_by_fh(clp, &args->cbl_fh);
 	if (!lo)
 		return NFS4ERR_NOMATCHING_LAYOUT;

 	ino = lo->plh_inode;
 	spin_lock(&ino->i_lock);
 	if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
 	    pnfs_mark_matching_lsegs_invalid(lo, &free_me_list,
 					&args->cbl_range))
 		rv = NFS4ERR_DELAY;
 	else
 		rv = NFS4ERR_NOMATCHING_LAYOUT;
 	pnfs_set_layout_stateid(lo, &args->cbl_stateid, true);
 	spin_unlock(&ino->i_lock);
 	pnfs_free_lseg_list(&free_me_list);
 	pnfs_put_layout_hdr(lo);
 	iput(ino);
 	return rv;
 }

 static u32 initiate_bulk_draining(struct nfs_client *clp,
 				  struct cb_layoutrecallargs *args)
 {
 	struct nfs_server *server;
 	struct pnfs_layout_hdr *lo;
 	struct inode *ino;
 	u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
 	struct pnfs_layout_hdr *tmp;
 	LIST_HEAD(recall_list);
 	LIST_HEAD(free_me_list);
 	struct pnfs_layout_range range = {
 		.iomode = IOMODE_ANY,
 		.offset = 0,
 		.length = NFS4_MAX_UINT64,
 	};

 	spin_lock(&clp->cl_lock);
 	rcu_read_lock();
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		if ((args->cbl_recall_type == RETURN_FSID) &&
 		    memcmp(&server->fsid, &args->cbl_fsid,
 			   sizeof(struct nfs_fsid)))
 			continue;

 		list_for_each_entry(lo, &server->layouts, plh_layouts) {
 			ino = igrab(lo->plh_inode);
 			if (!ino)
 				continue;
 			spin_lock(&ino->i_lock);
 			/* Is this layout in the process of being freed? */
 			if (NFS_I(ino)->layout != lo) {
 				spin_unlock(&ino->i_lock);
 				iput(ino);
 				continue;
 			}
 			pnfs_get_layout_hdr(lo);
 			spin_unlock(&ino->i_lock);
 			list_add(&lo->plh_bulk_recall, &recall_list);
 		}
 	}
 	rcu_read_unlock();
 	spin_unlock(&clp->cl_lock);

 	list_for_each_entry_safe(lo, tmp,
 				 &recall_list, plh_bulk_recall) {
 		ino = lo->plh_inode;
 		spin_lock(&ino->i_lock);
 		set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
 		if (pnfs_mark_matching_lsegs_invalid(lo, &free_me_list, &range))
 			rv = NFS4ERR_DELAY;
 		list_del_init(&lo->plh_bulk_recall);
 		spin_unlock(&ino->i_lock);
 		pnfs_free_lseg_list(&free_me_list);
 		pnfs_put_layout_hdr(lo);
 		iput(ino);
 	}
 	return rv;
 }

 static u32 do_callback_layoutrecall(struct nfs_client *clp,
 				    struct cb_layoutrecallargs *args)
 {
 	u32 res;

 	dprintk("%s enter, type=%i\n", __func__, args->cbl_recall_type);
 	if (args->cbl_recall_type == RETURN_FILE)
 		res = initiate_file_draining(clp, args);
 	else
 		res = initiate_bulk_draining(clp, args);
 	dprintk("%s returning %i\n", __func__, res);
 	return res;

 }

 __be32 nfs4_callback_layoutrecall(struct cb_layoutrecallargs *args,
 				  void *dummy, struct cb_process_state *cps)
 {
 	u32 res;

 	dprintk("%s: -->\n", __func__);

 	if (cps->clp)
 		res = do_callback_layoutrecall(cps->clp, args);
 	else
 		res = NFS4ERR_OP_NOT_IN_SESSION;

 	dprintk("%s: exit with status = %d\n", __func__, res);
 	return cpu_to_be32(res);
 }

 static void pnfs_recall_all_layouts(struct nfs_client *clp)
 {
 	struct cb_layoutrecallargs args;

 	/* Pretend we got a CB_LAYOUTRECALL(ALL) */
 	memset(&args, 0, sizeof(args));
 	args.cbl_recall_type = RETURN_ALL;
 	/* FIXME we ignore errors, what should we do? */
 	do_callback_layoutrecall(clp, &args);
 }

 __be32 nfs4_callback_devicenotify(struct cb_devicenotifyargs *args,
 				  void *dummy, struct cb_process_state *cps)
 {
 	int i;
 	__be32 res = 0;
 	struct nfs_client *clp = cps->clp;
 	struct nfs_server *server = NULL;

 	dprintk("%s: -->\n", __func__);

 	if (!clp) {
 		res = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
 		goto out;
 	}

 	for (i = 0; i < args->ndevs; i++) {
 		struct cb_devicenotifyitem *dev = &args->devs[i];

 		if (!server ||
 		    server->pnfs_curr_ld->id != dev->cbd_layout_type) {
 			rcu_read_lock();
 			list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 				if (server->pnfs_curr_ld &&
 				    server->pnfs_curr_ld->id == dev->cbd_layout_type) {
 					rcu_read_unlock();
 					goto found;
 				}
 			rcu_read_unlock();
 			dprintk("%s: layout type %u not found\n",
 				__func__, dev->cbd_layout_type);
 			continue;
 		}

 	found:
 		if (dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE)
 			dprintk("%s: NOTIFY_DEVICEID4_CHANGE not supported, "
 				"deleting instead\n", __func__);
 		nfs4_delete_deviceid(server->pnfs_curr_ld, clp, &dev->cbd_dev_id);
 	}

 out:
 	kfree(args->devs);
 	dprintk("%s: exit with status = %u\n",
 		__func__, be32_to_cpu(res));
 	return res;
 }

 /*
  * 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, 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
  * checking the used_slots bit array on the table.  The lower layer guarantees
  * a single outstanding callback request at a time.
  */
 static __be32
 validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
 {
 	struct nfs4_slot *slot;

 	dprintk("%s enter. slotid %d seqid %d\n",
 		__func__, args->csa_slotid, args->csa_sequenceid);

 	if (args->csa_slotid >= NFS41_BC_MAX_CALLBACKS)
 		return htonl(NFS4ERR_BADSLOT);

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

 	/* Normal */
 	if (likely(args->csa_sequenceid == slot->seq_nr + 1)) {
 		slot->seq_nr++;
 		goto out_ok;
 	}

 	/* Replay */
 	if (args->csa_sequenceid == slot->seq_nr) {
 		dprintk("%s seqid %d is a replay\n",
 			__func__, args->csa_sequenceid);
 		/* 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 */
 	if (args->csa_sequenceid == 1 && (slot->seq_nr + 1) == 0) {
 		slot->seq_nr = 1;
 		goto out_ok;
 	}

 	/* Misordered request */
 	return htonl(NFS4ERR_SEQ_MISORDERED);
 out_ok:
 	tbl->highest_used_slotid = args->csa_slotid;
 	return htonl(NFS4_OK);
 }

 /*
  * For each referring call triple, check the session's slot table for
  * a match.  If the slot is in use and the sequence numbers match, the
  * client is still waiting for a response to the original request.
  */
 static bool referring_call_exists(struct nfs_client *clp,
 				  uint32_t nrclists,
 				  struct referring_call_list *rclists)
 {
 	bool status = 0;
 	int i, j;
 	struct nfs4_session *session;
 	struct nfs4_slot_table *tbl;
 	struct referring_call_list *rclist;
 	struct referring_call *ref;

 	/*
 	 * XXX When client trunking is implemented, this becomes
 	 * a session lookup from within the loop
 	 */
 	session = clp->cl_session;
 	tbl = &session->fc_slot_table;

 	for (i = 0; i < nrclists; i++) {
 		rclist = &rclists[i];
 		if (memcmp(session->sess_id.data,
 			   rclist->rcl_sessionid.data,
 			   NFS4_MAX_SESSIONID_LEN) != 0)
 			continue;

 		for (j = 0; j < rclist->rcl_nrefcalls; j++) {
 			ref = &rclist->rcl_refcalls[j];

 			dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u "
 				"slotid %u\n", __func__,
 				((u32 *)&rclist->rcl_sessionid.data)[0],
 				((u32 *)&rclist->rcl_sessionid.data)[1],
 				((u32 *)&rclist->rcl_sessionid.data)[2],
 				((u32 *)&rclist->rcl_sessionid.data)[3],
 				ref->rc_sequenceid, ref->rc_slotid);

 			spin_lock(&tbl->slot_tbl_lock);
 			status = (test_bit(ref->rc_slotid, tbl->used_slots) &&
 				  tbl->slots[ref->rc_slotid].seq_nr ==
 					ref->rc_sequenceid);
 			spin_unlock(&tbl->slot_tbl_lock);
 			if (status)
 				goto out;
 		}
 	}

 out:
 	return status;
 }

 __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
 			      struct cb_sequenceres *res,
 			      struct cb_process_state *cps)
 {
 	struct nfs4_slot_table *tbl;
 	struct nfs_client *clp;
 	int i;
 	__be32 status = htonl(NFS4ERR_BADSESSION);

 	clp = nfs4_find_client_sessionid(cps->net, args->csa_addr, &args->csa_sessionid);
 	if (clp == NULL)
 		goto out;

 	tbl = &clp->cl_session->bc_slot_table;

 	spin_lock(&tbl->slot_tbl_lock);
 	/* state manager is resetting the session */
 	if (test_bit(NFS4_SESSION_DRAINING, &clp->cl_session->session_state)) {
 		spin_unlock(&tbl->slot_tbl_lock);
 		status = htonl(NFS4ERR_DELAY);
 		/* Return NFS4ERR_BADSESSION if we're draining the session
 		 * in order to reset it.
 		 */
 		if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state))
 			status = htonl(NFS4ERR_BADSESSION);
 		goto out;
 	}

 	status = validate_seqid(&clp->cl_session->bc_slot_table, args);
 	spin_unlock(&tbl->slot_tbl_lock);
 	if (status)
 		goto out;

 	cps->slotid = args->csa_slotid;

 	/*
 	 * Check for pending referring calls.  If a match is found, a
 	 * related callback was received before the response to the original
 	 * call.
 	 */
 	if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists)) {
 		status = htonl(NFS4ERR_DELAY);
 		goto out;
 	}

 	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:
 	cps->clp = clp; /* put in nfs4_callback_compound */
 	for (i = 0; i < args->csa_nrclists; i++)
 		kfree(args->csa_rclists[i].rcl_refcalls);
 	kfree(args->csa_rclists);

 	if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
 		cps->drc_status = status;
 		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;
 }

 static bool
 validate_bitmap_values(unsigned long mask)
 {
 	return (mask & ~RCA4_TYPE_MASK_ALL) == 0;
 }

 __be32 nfs4_callback_recallany(struct cb_recallanyargs *args, void *dummy,
 			       struct cb_process_state *cps)
 {
 	__be32 status;
 	fmode_t flags = 0;

 	status = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
 	if (!cps->clp) /* set in cb_sequence */
 		goto out;

 	dprintk_rcu("NFS: RECALL_ANY callback request from %s\n",
 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));

 	status = cpu_to_be32(NFS4ERR_INVAL);
 	if (!validate_bitmap_values(args->craa_type_mask))
 		goto out;

 	status = cpu_to_be32(NFS4_OK);
 	if (test_bit(RCA4_TYPE_MASK_RDATA_DLG, (const unsigned long *)
 		     &args->craa_type_mask))
 		flags = FMODE_READ;
 	if (test_bit(RCA4_TYPE_MASK_WDATA_DLG, (const unsigned long *)
 		     &args->craa_type_mask))
 		flags |= FMODE_WRITE;
 	if (test_bit(RCA4_TYPE_MASK_FILE_LAYOUT, (const unsigned long *)
 		     &args->craa_type_mask))
 		pnfs_recall_all_layouts(cps->clp);
 	if (flags)
 		nfs_expire_all_delegation_types(cps->clp, flags);
 out:
 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
 	return status;
 }

 /* Reduce the fore channel's max_slots to the target value */
 __be32 nfs4_callback_recallslot(struct cb_recallslotargs *args, void *dummy,
 				struct cb_process_state *cps)
 {
 	struct nfs4_slot_table *fc_tbl;
 	__be32 status;

 	status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
 	if (!cps->clp) /* set in cb_sequence */
 		goto out;

 	dprintk_rcu("NFS: CB_RECALL_SLOT request from %s target highest slotid %d\n",
 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR),
 		args->crsa_target_highest_slotid);

 	fc_tbl = &cps->clp->cl_session->fc_slot_table;

 	status = htonl(NFS4_OK);

 	nfs41_set_target_slotid(fc_tbl, args->crsa_target_highest_slotid);
 	nfs41_server_notify_target_slotid_update(cps->clp);
 out:
 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
 	return status;
 }
 #endif /* CONFIG_NFS_V4_1 */
	/*
	* linux/fs/nfs/callback_proc.c
	*
	* Copyright (C) 2004 Trond Myklebust
	*
	* NFSv4 callback procedures
	*/
	#include <linux/nfs4.h>
	#include <linux/nfs_fs.h>
	#include <linux/slab.h>
	#include <linux/rcupdate.h>
	#include "nfs4_fs.h"
	#include "callback.h"
	#include "delegation.h"
	#include "internal.h"
	#include "pnfs.h"
	#include "nfs4session.h"

	#ifdef NFS_DEBUG
	#define NFSDBG_FACILITY NFSDBG_CALLBACK
	#endif

	__be32 nfs4_callback_getattr(struct cb_getattrargs *args,
	struct cb_getattrres *res,
	struct cb_process_state *cps)
	{
	struct nfs_delegation *delegation;
	struct nfs_inode *nfsi;
	struct inode *inode;

	res->status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
	if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
	goto out;

	res->bitmap[0] = res->bitmap[1] = 0;
	res->status = htonl(NFS4ERR_BADHANDLE);

	dprintk_rcu("NFS: GETATTR callback request from %s\n",
	rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));

	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
	if (inode == NULL)
	goto out;
	nfsi = NFS_I(inode);
	rcu_read_lock();
	delegation = rcu_dereference(nfsi->delegation);
	if (delegation == NULL \|\| (delegation->type & FMODE_WRITE) == 0)
	goto out_iput;
	res->size = i_size_read(inode);
	res->change_attr = delegation->change_attr;
	if (nfsi->npages != 0)
	res->change_attr++;
	res->ctime = inode->i_ctime;
	res->mtime = inode->i_mtime;
	res->bitmap[0] = (FATTR4_WORD0_CHANGE\|FATTR4_WORD0_SIZE) &
	args->bitmap[0];
	res->bitmap[1] = (FATTR4_WORD1_TIME_METADATA\|FATTR4_WORD1_TIME_MODIFY) &
	args->bitmap[1];
	res->status = 0;
	out_iput:
	rcu_read_unlock();
	iput(inode);
	out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(res->status));
	return res->status;
	}

	__be32 nfs4_callback_recall(struct cb_recallargs args, void dummy,
	struct cb_process_state *cps)
	{
	struct inode *inode;
	__be32 res;

	res = htonl(NFS4ERR_OP_NOT_IN_SESSION);
	if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
	goto out;

	dprintk_rcu("NFS: RECALL callback request from %s\n",
	rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));

	res = htonl(NFS4ERR_BADHANDLE);
	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
	if (inode == NULL)
	goto out;
	/* Set up a helper thread to actually return the delegation */
	switch (nfs_async_inode_return_delegation(inode, &args->stateid)) {
	case 0:
	res = 0;
	break;
	case -ENOENT:
	res = htonl(NFS4ERR_BAD_STATEID);
	break;
	default:
	res = htonl(NFS4ERR_RESOURCE);
	}
	iput(inode);
	out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(res));
	return res;
	}

	#if defined(CONFIG_NFS_V4_1)

	/*
	* Lookup a layout by filehandle.
	*
	* Note: gets a refcount on the layout hdr and on its respective inode.
	* Caller must put the layout hdr and the inode.
	*
	* TODO: keep track of all layouts (and delegations) in a hash table
	* hashed by filehandle.
	*/
	static struct pnfs_layout_hdr * get_layout_by_fh_locked(struct nfs_client clp, struct nfs_fh fh)
	{
	struct nfs_server *server;
	struct inode *ino;
	struct pnfs_layout_hdr *lo;

	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
	list_for_each_entry(lo, &server->layouts, plh_layouts) {
	if (nfs_compare_fh(fh, &NFS_I(lo->plh_inode)->fh))
	continue;
	ino = igrab(lo->plh_inode);
	if (!ino)
	continue;
	spin_lock(&ino->i_lock);
	/* Is this layout in the process of being freed? */
	if (NFS_I(ino)->layout != lo) {
	spin_unlock(&ino->i_lock);
	iput(ino);
	continue;
	}
	pnfs_get_layout_hdr(lo);
	spin_unlock(&ino->i_lock);
	return lo;
	}
	}

	return NULL;
	}

	static struct pnfs_layout_hdr * get_layout_by_fh(struct nfs_client clp, struct nfs_fh fh)
	{
	struct pnfs_layout_hdr *lo;

	spin_lock(&clp->cl_lock);
	rcu_read_lock();
	lo = get_layout_by_fh_locked(clp, fh);
	rcu_read_unlock();
	spin_unlock(&clp->cl_lock);

	return lo;
	}

	static u32 initiate_file_draining(struct nfs_client *clp,
	struct cb_layoutrecallargs *args)
	{
	struct inode *ino;
	struct pnfs_layout_hdr *lo;
	u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
	LIST_HEAD(free_me_list);

	lo = get_layout_by_fh(clp, &args->cbl_fh);
	if (!lo)
	return NFS4ERR_NOMATCHING_LAYOUT;

	ino = lo->plh_inode;
	spin_lock(&ino->i_lock);
	if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) \|\|
	pnfs_mark_matching_lsegs_invalid(lo, &free_me_list,
	&args->cbl_range))
	rv = NFS4ERR_DELAY;
	else
	rv = NFS4ERR_NOMATCHING_LAYOUT;
	pnfs_set_layout_stateid(lo, &args->cbl_stateid, true);
	spin_unlock(&ino->i_lock);
	pnfs_free_lseg_list(&free_me_list);
	pnfs_put_layout_hdr(lo);
	iput(ino);
	return rv;
	}

	static u32 initiate_bulk_draining(struct nfs_client *clp,
	struct cb_layoutrecallargs *args)
	{
	struct nfs_server *server;
	struct pnfs_layout_hdr *lo;
	struct inode *ino;
	u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
	struct pnfs_layout_hdr *tmp;
	LIST_HEAD(recall_list);
	LIST_HEAD(free_me_list);
	struct pnfs_layout_range range = {
	.iomode = IOMODE_ANY,
	.offset = 0,
	.length = NFS4_MAX_UINT64,
	};

	spin_lock(&clp->cl_lock);
	rcu_read_lock();
	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
	if ((args->cbl_recall_type == RETURN_FSID) &&
	memcmp(&server->fsid, &args->cbl_fsid,
	sizeof(struct nfs_fsid)))
	continue;

	list_for_each_entry(lo, &server->layouts, plh_layouts) {
	ino = igrab(lo->plh_inode);
	if (!ino)
	continue;
	spin_lock(&ino->i_lock);
	/* Is this layout in the process of being freed? */
	if (NFS_I(ino)->layout != lo) {
	spin_unlock(&ino->i_lock);
	iput(ino);
	continue;
	}
	pnfs_get_layout_hdr(lo);
	spin_unlock(&ino->i_lock);
	list_add(&lo->plh_bulk_recall, &recall_list);
	}
	}
	rcu_read_unlock();
	spin_unlock(&clp->cl_lock);

	list_for_each_entry_safe(lo, tmp,
	&recall_list, plh_bulk_recall) {
	ino = lo->plh_inode;
	spin_lock(&ino->i_lock);
	set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
	if (pnfs_mark_matching_lsegs_invalid(lo, &free_me_list, &range))
	rv = NFS4ERR_DELAY;
	list_del_init(&lo->plh_bulk_recall);
	spin_unlock(&ino->i_lock);
	pnfs_free_lseg_list(&free_me_list);
	pnfs_put_layout_hdr(lo);
	iput(ino);
	}
	return rv;
	}

	static u32 do_callback_layoutrecall(struct nfs_client *clp,
	struct cb_layoutrecallargs *args)
	{
	u32 res;

	dprintk("%s enter, type=%i\n", __func__, args->cbl_recall_type);
	if (args->cbl_recall_type == RETURN_FILE)
	res = initiate_file_draining(clp, args);
	else
	res = initiate_bulk_draining(clp, args);
	dprintk("%s returning %i\n", __func__, res);
	return res;

	}

	__be32 nfs4_callback_layoutrecall(struct cb_layoutrecallargs *args,
	void dummy, struct cb_process_state cps)
	{
	u32 res;

	dprintk("%s: -->\n", __func__);

	if (cps->clp)
	res = do_callback_layoutrecall(cps->clp, args);
	else
	res = NFS4ERR_OP_NOT_IN_SESSION;

	dprintk("%s: exit with status = %d\n", __func__, res);
	return cpu_to_be32(res);
	}

	static void pnfs_recall_all_layouts(struct nfs_client *clp)
	{
	struct cb_layoutrecallargs args;

	/* Pretend we got a CB_LAYOUTRECALL(ALL) */
	memset(&args, 0, sizeof(args));
	args.cbl_recall_type = RETURN_ALL;
	/* FIXME we ignore errors, what should we do? */
	do_callback_layoutrecall(clp, &args);
	}

	__be32 nfs4_callback_devicenotify(struct cb_devicenotifyargs *args,
	void dummy, struct cb_process_state cps)
	{
	int i;
	__be32 res = 0;
	struct nfs_client *clp = cps->clp;
	struct nfs_server *server = NULL;

	dprintk("%s: -->\n", __func__);

	if (!clp) {
	res = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
	goto out;
	}

	for (i = 0; i < args->ndevs; i++) {
	struct cb_devicenotifyitem *dev = &args->devs[i];

	if (!server \|\|
	server->pnfs_curr_ld->id != dev->cbd_layout_type) {
	rcu_read_lock();
	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
	if (server->pnfs_curr_ld &&
	server->pnfs_curr_ld->id == dev->cbd_layout_type) {
	rcu_read_unlock();
	goto found;
	}
	rcu_read_unlock();
	dprintk("%s: layout type %u not found\n",
	__func__, dev->cbd_layout_type);
	continue;
	}

	found:
	if (dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE)
	dprintk("%s: NOTIFY_DEVICEID4_CHANGE not supported, "
	"deleting instead\n", __func__);
	nfs4_delete_deviceid(server->pnfs_curr_ld, clp, &dev->cbd_dev_id);
	}

	out:
	kfree(args->devs);
	dprintk("%s: exit with status = %u\n",
	__func__, be32_to_cpu(res));
	return res;
	}

	/*
	* 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, 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
	* checking the used_slots bit array on the table. The lower layer guarantees
	* a single outstanding callback request at a time.
	*/
	static __be32
	validate_seqid(struct nfs4_slot_table tbl, struct cb_sequenceargs args)
	{
	struct nfs4_slot *slot;

	dprintk("%s enter. slotid %d seqid %d\n",
	__func__, args->csa_slotid, args->csa_sequenceid);

	if (args->csa_slotid >= NFS41_BC_MAX_CALLBACKS)
	return htonl(NFS4ERR_BADSLOT);

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

	/* Normal */
	if (likely(args->csa_sequenceid == slot->seq_nr + 1)) {
	slot->seq_nr++;
	goto out_ok;
	}

	/* Replay */
	if (args->csa_sequenceid == slot->seq_nr) {
	dprintk("%s seqid %d is a replay\n",
	__func__, args->csa_sequenceid);
	/* 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 */
	if (args->csa_sequenceid == 1 && (slot->seq_nr + 1) == 0) {
	slot->seq_nr = 1;
	goto out_ok;
	}

	/* Misordered request */
	return htonl(NFS4ERR_SEQ_MISORDERED);
	out_ok:
	tbl->highest_used_slotid = args->csa_slotid;
	return htonl(NFS4_OK);
	}

	/*
	* For each referring call triple, check the session's slot table for
	* a match. If the slot is in use and the sequence numbers match, the
	* client is still waiting for a response to the original request.
	*/
	static bool referring_call_exists(struct nfs_client *clp,
	uint32_t nrclists,
	struct referring_call_list *rclists)
	{
	bool status = 0;
	int i, j;
	struct nfs4_session *session;
	struct nfs4_slot_table *tbl;
	struct referring_call_list *rclist;
	struct referring_call *ref;

	/*
	* XXX When client trunking is implemented, this becomes
	* a session lookup from within the loop
	*/
	session = clp->cl_session;
	tbl = &session->fc_slot_table;

	for (i = 0; i < nrclists; i++) {
	rclist = &rclists[i];
	if (memcmp(session->sess_id.data,
	rclist->rcl_sessionid.data,
	NFS4_MAX_SESSIONID_LEN) != 0)
	continue;

	for (j = 0; j < rclist->rcl_nrefcalls; j++) {
	ref = &rclist->rcl_refcalls[j];

	dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u "
	"slotid %u\n", __func__,
	((u32 *)&rclist->rcl_sessionid.data)[0],
	((u32 *)&rclist->rcl_sessionid.data)[1],
	((u32 *)&rclist->rcl_sessionid.data)[2],
	((u32 *)&rclist->rcl_sessionid.data)[3],
	ref->rc_sequenceid, ref->rc_slotid);

	spin_lock(&tbl->slot_tbl_lock);
	status = (test_bit(ref->rc_slotid, tbl->used_slots) &&
	tbl->slots[ref->rc_slotid].seq_nr ==
	ref->rc_sequenceid);
	spin_unlock(&tbl->slot_tbl_lock);
	if (status)
	goto out;
	}
	}

	out:
	return status;
	}

	__be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
	struct cb_sequenceres *res,
	struct cb_process_state *cps)
	{
	struct nfs4_slot_table *tbl;
	struct nfs_client *clp;
	int i;
	__be32 status = htonl(NFS4ERR_BADSESSION);

	clp = nfs4_find_client_sessionid(cps->net, args->csa_addr, &args->csa_sessionid);
	if (clp == NULL)
	goto out;

	tbl = &clp->cl_session->bc_slot_table;

	spin_lock(&tbl->slot_tbl_lock);
	/* state manager is resetting the session */
	if (test_bit(NFS4_SESSION_DRAINING, &clp->cl_session->session_state)) {
	spin_unlock(&tbl->slot_tbl_lock);
	status = htonl(NFS4ERR_DELAY);
	/* Return NFS4ERR_BADSESSION if we're draining the session
	* in order to reset it.
	*/
	if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state))
	status = htonl(NFS4ERR_BADSESSION);
	goto out;
	}

	status = validate_seqid(&clp->cl_session->bc_slot_table, args);
	spin_unlock(&tbl->slot_tbl_lock);
	if (status)
	goto out;

	cps->slotid = args->csa_slotid;

	/*
	* Check for pending referring calls. If a match is found, a
	* related callback was received before the response to the original
	* call.
	*/
	if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists)) {
	status = htonl(NFS4ERR_DELAY);
	goto out;
	}

	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:
	cps->clp = clp; /* put in nfs4_callback_compound */
	for (i = 0; i < args->csa_nrclists; i++)
	kfree(args->csa_rclists[i].rcl_refcalls);
	kfree(args->csa_rclists);

	if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
	cps->drc_status = status;
	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;
	}

	static bool
	validate_bitmap_values(unsigned long mask)
	{
	return (mask & ~RCA4_TYPE_MASK_ALL) == 0;
	}

	__be32 nfs4_callback_recallany(struct cb_recallanyargs args, void dummy,
	struct cb_process_state *cps)
	{
	__be32 status;
	fmode_t flags = 0;

	status = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
	if (!cps->clp) /* set in cb_sequence */
	goto out;

	dprintk_rcu("NFS: RECALL_ANY callback request from %s\n",
	rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));

	status = cpu_to_be32(NFS4ERR_INVAL);
	if (!validate_bitmap_values(args->craa_type_mask))
	goto out;

	status = cpu_to_be32(NFS4_OK);
	if (test_bit(RCA4_TYPE_MASK_RDATA_DLG, (const unsigned long *)
	&args->craa_type_mask))
	flags = FMODE_READ;
	if (test_bit(RCA4_TYPE_MASK_WDATA_DLG, (const unsigned long *)
	&args->craa_type_mask))
	flags \|= FMODE_WRITE;
	if (test_bit(RCA4_TYPE_MASK_FILE_LAYOUT, (const unsigned long *)
	&args->craa_type_mask))
	pnfs_recall_all_layouts(cps->clp);
	if (flags)
	nfs_expire_all_delegation_types(cps->clp, flags);
	out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
	return status;
	}

	/* Reduce the fore channel's max_slots to the target value */
	__be32 nfs4_callback_recallslot(struct cb_recallslotargs args, void dummy,
	struct cb_process_state *cps)
	{
	struct nfs4_slot_table *fc_tbl;
	__be32 status;

	status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
	if (!cps->clp) /* set in cb_sequence */
	goto out;

	dprintk_rcu("NFS: CB_RECALL_SLOT request from %s target highest slotid %d\n",
	rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR),
	args->crsa_target_highest_slotid);

	fc_tbl = &cps->clp->cl_session->fc_slot_table;

	status = htonl(NFS4_OK);

	nfs41_set_target_slotid(fc_tbl, args->crsa_target_highest_slotid);
	nfs41_server_notify_target_slotid_update(cps->clp);
	out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
	return status;
	}
	#endif /* CONFIG_NFS_V4_1 */