/*
 * 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"

#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;
                        get_layout_hdr(lo);
                        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) ||
            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;

        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 max slots %d\n",
                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\n", __func__, ntohl(status));
        return status;
}
#endif /* CONFIG_NFS_V4_1 */