/*
   * 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 "nfs4_fs.h"

  #include "callback.h"
  #include "delegation.h"

  #include "internal.h"

  #include "pnfs.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("NFS: GETATTR callback request from %s
  ",

  		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
  ", __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("NFS: RECALL callback request from %s
  ",

  		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:
  		if (res != 0)
  			res = htonl(NFS4ERR_BAD_STATEID);
  		break;
  	default:
  		res = htonl(NFS4ERR_RESOURCE);
  	}
  	iput(inode);

  out:

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

  	return res;
  }

  int nfs4_validate_delegation_stateid(struct nfs_delegation *delegation, const nfs4_stateid *stateid)
  {
  	if (delegation == NULL || memcmp(delegation->stateid.data, stateid->data,
  					 sizeof(delegation->stateid.data)) != 0)
  		return 0;
  	return 1;
  }

  #if defined(CONFIG_NFS_V4_1)

  static u32 initiate_file_draining(struct nfs_client *clp,
  				  struct cb_layoutrecallargs *args)
  {

  	struct nfs_server *server;

  	struct pnfs_layout_hdr *lo;
  	struct inode *ino;
  	bool found = false;
  	u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
  	LIST_HEAD(free_me_list);
  
  	spin_lock(&clp->cl_lock);

  	rcu_read_lock();
  	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
  		list_for_each_entry(lo, &server->layouts, plh_layouts) {
  			if (nfs_compare_fh(&args->cbl_fh,
  					   &NFS_I(lo->plh_inode)->fh))
  				continue;
  			ino = igrab(lo->plh_inode);
  			if (!ino)
  				continue;
  			found = true;
  			/* Without this, layout can be freed as soon
  			 * as we release cl_lock.
  			 */
  			get_layout_hdr(lo);
  			break;
  		}
  		if (found)
  			break;

  	}

  	rcu_read_unlock();

  	spin_unlock(&clp->cl_lock);

  	if (!found)
  		return NFS4ERR_NOMATCHING_LAYOUT;
  
  	spin_lock(&ino->i_lock);
  	if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
  	    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);
  	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) {
  			if (!igrab(lo->plh_inode))
  				continue;
  			get_layout_hdr(lo);
  			BUG_ON(!list_empty(&lo->plh_bulk_recall));
  			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 (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);

  		put_layout_hdr(lo);
  		iput(ino);
  	}

  	return rv;
  }
  
  static u32 do_callback_layoutrecall(struct nfs_client *clp,
  				    struct cb_layoutrecallargs *args)
  {
  	u32 res = NFS4ERR_DELAY;
  
  	dprintk("%s enter, type=%i
  ", __func__, args->cbl_recall_type);
  	if (test_and_set_bit(NFS4CLNT_LAYOUTRECALL, &clp->cl_state))
  		goto out;
  	if (args->cbl_recall_type == RETURN_FILE)
  		res = initiate_file_draining(clp, args);
  	else
  		res = initiate_bulk_draining(clp, args);
  	clear_bit(NFS4CLNT_LAYOUTRECALL, &clp->cl_state);
  out:
  	dprintk("%s returning %i
  ", __func__, res);
  	return res;
  
  }

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

  	u32 res;
  
  	dprintk("%s: -->
  ", __func__);
  
  	if (cps->clp)
  		res = do_callback_layoutrecall(cps->clp, args);
  	else
  		res = NFS4ERR_OP_NOT_IN_SESSION;
  
  	dprintk("%s: exit with status = %d
  ", __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: -->
  ", __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
  ",
  				__func__, dev->cbd_layout_type);
  			continue;
  		}
  
  	found:
  		if (dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE)
  			dprintk("%s: NOTIFY_DEVICEID4_CHANGE not supported, "
  				"deleting instead
  ", __func__);

  		nfs4_delete_deviceid(server->pnfs_curr_ld, clp, &dev->cbd_dev_id);

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

  int nfs41_validate_delegation_stateid(struct nfs_delegation *delegation, const nfs4_stateid *stateid)
  {
  	if (delegation == NULL)
  		return 0;

  	if (stateid->stateid.seqid != 0)

  		return 0;

  	if (memcmp(&delegation->stateid.stateid.other,
  		   &stateid->stateid.other,
  		   NFS4_STATEID_OTHER_SIZE))

  		return 0;
  
  	return 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, 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
  ",

  		__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
  ", __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
  ",

  			__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
  ", __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(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
  ", __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("NFS: RECALL_ANY callback request from %s
  ",

  		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
  ", __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("NFS: CB_RECALL_SLOT request from %s target max slots %d
  ",

  		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR),

  		args->crsa_target_max_slots);

  	fc_tbl = &cps->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;

  
  	status = htonl(NFS4_OK);
  	if (args->crsa_target_max_slots == fc_tbl->max_slots)

  		goto out;

  
  	fc_tbl->target_max_slots = args->crsa_target_max_slots;

  	nfs41_handle_recall_slot(cps->clp);

  out:
  	dprintk("%s: exit with status = %d
  ", __func__, ntohl(status));
  	return status;
  }

  #endif /* CONFIG_NFS_V4_1 */