nfs41: kick start nfs41 session recovery when handling errors

[mv-sheeva.git] / fs / nfs / nfs4proc.c

/*
 *  fs/nfs/nfs4proc.c
 *
 *  Client-side procedure declarations for NFSv4.
 *
 *  Copyright (c) 2002 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Kendrick Smith <kmsmith@umich.edu>
 *  Andy Adamson   <andros@umich.edu>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/mm.h>
#include <linux/utsname.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/smp_lock.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/module.h>

#include "nfs4_fs.h"
#include "delegation.h"
#include "internal.h"
#include "iostat.h"
#include "callback.h"

#define NFSDBG_FACILITY         NFSDBG_PROC

#define NFS4_POLL_RETRY_MIN     (HZ/10)
#define NFS4_POLL_RETRY_MAX     (15*HZ)

struct nfs4_opendata;
static int _nfs4_proc_open(struct nfs4_opendata *data);
static int nfs4_do_fsinfo(struct nfs_server *, struct nfs_fh *, struct nfs_fsinfo *);
static int nfs4_async_handle_error(struct rpc_task *, const struct nfs_server *, struct nfs4_state *);
static int _nfs4_proc_lookup(struct inode *dir, const struct qstr *name, struct nfs_fh *fhandle, struct nfs_fattr *fattr);
static int _nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fattr *fattr);

/* Prevent leaks of NFSv4 errors into userland */
static int nfs4_map_errors(int err)
{
        if (err < -1000) {
                dprintk("%s could not handle NFSv4 error %d\n",
                                __func__, -err);
                return -EIO;
        }
        return err;
}

/*
 * This is our standard bitmap for GETATTR requests.
 */
const u32 nfs4_fattr_bitmap[2] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_SIZE
        | FATTR4_WORD0_FSID
        | FATTR4_WORD0_FILEID,
        FATTR4_WORD1_MODE
        | FATTR4_WORD1_NUMLINKS
        | FATTR4_WORD1_OWNER
        | FATTR4_WORD1_OWNER_GROUP
        | FATTR4_WORD1_RAWDEV
        | FATTR4_WORD1_SPACE_USED
        | FATTR4_WORD1_TIME_ACCESS
        | FATTR4_WORD1_TIME_METADATA
        | FATTR4_WORD1_TIME_MODIFY
};

const u32 nfs4_statfs_bitmap[2] = {
        FATTR4_WORD0_FILES_AVAIL
        | FATTR4_WORD0_FILES_FREE
        | FATTR4_WORD0_FILES_TOTAL,
        FATTR4_WORD1_SPACE_AVAIL
        | FATTR4_WORD1_SPACE_FREE
        | FATTR4_WORD1_SPACE_TOTAL
};

const u32 nfs4_pathconf_bitmap[2] = {
        FATTR4_WORD0_MAXLINK
        | FATTR4_WORD0_MAXNAME,
        0
};

const u32 nfs4_fsinfo_bitmap[2] = { FATTR4_WORD0_MAXFILESIZE
                        | FATTR4_WORD0_MAXREAD
                        | FATTR4_WORD0_MAXWRITE
                        | FATTR4_WORD0_LEASE_TIME,
                        0
};

const u32 nfs4_fs_locations_bitmap[2] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_SIZE
        | FATTR4_WORD0_FSID
        | FATTR4_WORD0_FILEID
        | FATTR4_WORD0_FS_LOCATIONS,
        FATTR4_WORD1_MODE
        | FATTR4_WORD1_NUMLINKS
        | FATTR4_WORD1_OWNER
        | FATTR4_WORD1_OWNER_GROUP
        | FATTR4_WORD1_RAWDEV
        | FATTR4_WORD1_SPACE_USED
        | FATTR4_WORD1_TIME_ACCESS
        | FATTR4_WORD1_TIME_METADATA
        | FATTR4_WORD1_TIME_MODIFY
        | FATTR4_WORD1_MOUNTED_ON_FILEID
};

static void nfs4_setup_readdir(u64 cookie, __be32 *verifier, struct dentry *dentry,
                struct nfs4_readdir_arg *readdir)
{
        __be32 *start, *p;

        BUG_ON(readdir->count < 80);
        if (cookie > 2) {
                readdir->cookie = cookie;
                memcpy(&readdir->verifier, verifier, sizeof(readdir->verifier));
                return;
        }

        readdir->cookie = 0;
        memset(&readdir->verifier, 0, sizeof(readdir->verifier));
        if (cookie == 2)
                return;
        
        /*
         * NFSv4 servers do not return entries for '.' and '..'
         * Therefore, we fake these entries here.  We let '.'
         * have cookie 0 and '..' have cookie 1.  Note that
         * when talking to the server, we always send cookie 0
         * instead of 1 or 2.
         */
        start = p = kmap_atomic(*readdir->pages, KM_USER0);
        
        if (cookie == 0) {
                *p++ = xdr_one;                                  /* next */
                *p++ = xdr_zero;                   /* cookie, first word */
                *p++ = xdr_one;                   /* cookie, second word */
                *p++ = xdr_one;                             /* entry len */
                memcpy(p, ".\0\0\0", 4);                        /* entry */
                p++;
                *p++ = xdr_one;                         /* bitmap length */
                *p++ = htonl(FATTR4_WORD0_FILEID);             /* bitmap */
                *p++ = htonl(8);              /* attribute buffer length */
                p = xdr_encode_hyper(p, NFS_FILEID(dentry->d_inode));
        }
        
        *p++ = xdr_one;                                  /* next */
        *p++ = xdr_zero;                   /* cookie, first word */
        *p++ = xdr_two;                   /* cookie, second word */
        *p++ = xdr_two;                             /* entry len */
        memcpy(p, "..\0\0", 4);                         /* entry */
        p++;
        *p++ = xdr_one;                         /* bitmap length */
        *p++ = htonl(FATTR4_WORD0_FILEID);             /* bitmap */
        *p++ = htonl(8);              /* attribute buffer length */
        p = xdr_encode_hyper(p, NFS_FILEID(dentry->d_parent->d_inode));

        readdir->pgbase = (char *)p - (char *)start;
        readdir->count -= readdir->pgbase;
        kunmap_atomic(start, KM_USER0);
}

static int nfs4_wait_clnt_recover(struct nfs_client *clp)
{
        int res;

        might_sleep();

        res = wait_on_bit(&clp->cl_state, NFS4CLNT_MANAGER_RUNNING,
                        nfs_wait_bit_killable, TASK_KILLABLE);
        return res;
}

static int nfs4_delay(struct rpc_clnt *clnt, long *timeout)
{
        int res = 0;

        might_sleep();

        if (*timeout <= 0)
                *timeout = NFS4_POLL_RETRY_MIN;
        if (*timeout > NFS4_POLL_RETRY_MAX)
                *timeout = NFS4_POLL_RETRY_MAX;
        schedule_timeout_killable(*timeout);
        if (fatal_signal_pending(current))
                res = -ERESTARTSYS;
        *timeout <<= 1;
        return res;
}

/* This is the error handling routine for processes that are allowed
 * to sleep.
 */
static int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
{
        struct nfs_client *clp = server->nfs_client;
        struct nfs4_state *state = exception->state;
        int ret = errorcode;

        exception->retry = 0;
        switch(errorcode) {
                case 0:
                        return 0;
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_OPENMODE:
                        if (state == NULL)
                                break;
                        nfs4_state_mark_reclaim_nograce(clp, state);
                case -NFS4ERR_STALE_CLIENTID:
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_EXPIRED:
                        nfs4_schedule_state_recovery(clp);
                        ret = nfs4_wait_clnt_recover(clp);
                        if (ret == 0)
                                exception->retry = 1;
#if !defined(CONFIG_NFS_V4_1)
                        break;
#else /* !defined(CONFIG_NFS_V4_1) */
                        if (!nfs4_has_session(server->nfs_client))
                                break;
                        /* FALLTHROUGH */
                case -NFS4ERR_BADSESSION:
                case -NFS4ERR_BADSLOT:
                case -NFS4ERR_BAD_HIGH_SLOT:
                case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
                case -NFS4ERR_DEADSESSION:
                case -NFS4ERR_SEQ_FALSE_RETRY:
                case -NFS4ERR_SEQ_MISORDERED:
                        dprintk("%s ERROR: %d Reset session\n", __func__,
                                errorcode);
                        set_bit(NFS4CLNT_SESSION_SETUP, &clp->cl_state);
                        exception->retry = 1;
                        /* FALLTHROUGH */
#endif /* !defined(CONFIG_NFS_V4_1) */
                case -NFS4ERR_FILE_OPEN:
                case -NFS4ERR_GRACE:
                case -NFS4ERR_DELAY:
                        ret = nfs4_delay(server->client, &exception->timeout);
                        if (ret != 0)
                                break;
                case -NFS4ERR_OLD_STATEID:
                        exception->retry = 1;
        }
        /* We failed to handle the error */
        return nfs4_map_errors(ret);
}


static void renew_lease(const struct nfs_server *server, unsigned long timestamp)
{
        struct nfs_client *clp = server->nfs_client;
        spin_lock(&clp->cl_lock);
        if (time_before(clp->cl_last_renewal,timestamp))
                clp->cl_last_renewal = timestamp;
        spin_unlock(&clp->cl_lock);
}

#if defined(CONFIG_NFS_V4_1)

/*
 * nfs4_free_slot - free a slot and efficiently update slot table.
 *
 * freeing a slot is trivially done by clearing its respective bit
 * in the bitmap.
 * If the freed slotid equals highest_used_slotid we want to update it
 * so that the server would be able to size down the slot table if needed,
 * otherwise we know that the highest_used_slotid is still in use.
 * When updating highest_used_slotid there may be "holes" in the bitmap
 * so we need to scan down from highest_used_slotid to 0 looking for the now
 * highest slotid in use.
 * If none found, highest_used_slotid is set to -1.
 */
static void
nfs4_free_slot(struct nfs4_slot_table *tbl, u8 free_slotid)
{
        int slotid = free_slotid;

        spin_lock(&tbl->slot_tbl_lock);
        /* clear used bit in bitmap */
        __clear_bit(slotid, tbl->used_slots);

        /* update highest_used_slotid when it is freed */
        if (slotid == tbl->highest_used_slotid) {
                slotid = find_last_bit(tbl->used_slots, tbl->max_slots);
                if (slotid >= 0 && slotid < tbl->max_slots)
                        tbl->highest_used_slotid = slotid;
                else
                        tbl->highest_used_slotid = -1;
        }
        rpc_wake_up_next(&tbl->slot_tbl_waitq);
        spin_unlock(&tbl->slot_tbl_lock);
        dprintk("%s: free_slotid %u highest_used_slotid %d\n", __func__,
                free_slotid, tbl->highest_used_slotid);
}

void nfs41_sequence_free_slot(const struct nfs_client *clp,
                              struct nfs4_sequence_res *res)
{
        struct nfs4_slot_table *tbl;

        if (!nfs4_has_session(clp)) {
                dprintk("%s: No session\n", __func__);
                return;
        }
        tbl = &clp->cl_session->fc_slot_table;
        if (res->sr_slotid == NFS4_MAX_SLOT_TABLE) {
                dprintk("%s: No slot\n", __func__);
                /* just wake up the next guy waiting since
                 * we may have not consumed a slot after all */
                rpc_wake_up_next(&tbl->slot_tbl_waitq);
                return;
        }
        nfs4_free_slot(tbl, res->sr_slotid);
        res->sr_slotid = NFS4_MAX_SLOT_TABLE;
}

static void nfs41_sequence_done(struct nfs_client *clp,
                                struct nfs4_sequence_res *res,
                                int rpc_status)
{
        unsigned long timestamp;
        struct nfs4_slot_table *tbl;
        struct nfs4_slot *slot;

        /*
         * sr_status remains 1 if an RPC level error occurred. The server
         * may or may not have processed the sequence operation..
         * Proceed as if the server received and processed the sequence
         * operation.
         */
        if (res->sr_status == 1)
                res->sr_status = NFS_OK;

        /* -ERESTARTSYS can result in skipping nfs41_sequence_setup */
        if (res->sr_slotid == NFS4_MAX_SLOT_TABLE)
                goto out;

        tbl = &clp->cl_session->fc_slot_table;
        slot = tbl->slots + res->sr_slotid;

        if (res->sr_status == 0) {
                /* Update the slot's sequence and clientid lease timer */
                ++slot->seq_nr;
                timestamp = res->sr_renewal_time;
                spin_lock(&clp->cl_lock);
                if (time_before(clp->cl_last_renewal, timestamp))
                        clp->cl_last_renewal = timestamp;
                spin_unlock(&clp->cl_lock);
                return;
        }
out:
        /* The session may be reset by one of the error handlers. */
        dprintk("%s: Error %d free the slot \n", __func__, res->sr_status);
        nfs41_sequence_free_slot(clp, res);
}

/*
 * nfs4_find_slot - efficiently look for a free slot
 *
 * nfs4_find_slot looks for an unset bit in the used_slots bitmap.
 * If found, we mark the slot as used, update the highest_used_slotid,
 * and respectively set up the sequence operation args.
 * The slot number is returned if found, or NFS4_MAX_SLOT_TABLE otherwise.
 *
 * Note: must be called with under the slot_tbl_lock.
 */
static u8
nfs4_find_slot(struct nfs4_slot_table *tbl, struct rpc_task *task)
{
        int slotid;
        u8 ret_id = NFS4_MAX_SLOT_TABLE;
        BUILD_BUG_ON((u8)NFS4_MAX_SLOT_TABLE != (int)NFS4_MAX_SLOT_TABLE);

        dprintk("--> %s used_slots=%04lx highest_used=%d max_slots=%d\n",
                __func__, tbl->used_slots[0], tbl->highest_used_slotid,
                tbl->max_slots);
        slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slots);
        if (slotid >= tbl->max_slots)
                goto out;
        __set_bit(slotid, tbl->used_slots);
        if (slotid > tbl->highest_used_slotid)
                tbl->highest_used_slotid = slotid;
        ret_id = slotid;
out:
        dprintk("<-- %s used_slots=%04lx highest_used=%d slotid=%d \n",
                __func__, tbl->used_slots[0], tbl->highest_used_slotid, ret_id);
        return ret_id;
}

static int nfs41_setup_sequence(struct nfs4_session *session,
                                struct nfs4_sequence_args *args,
                                struct nfs4_sequence_res *res,
                                int cache_reply,
                                struct rpc_task *task)
{
        struct nfs4_slot *slot;
        struct nfs4_slot_table *tbl;
        u8 slotid;

        dprintk("--> %s\n", __func__);
        /* slot already allocated? */
        if (res->sr_slotid != NFS4_MAX_SLOT_TABLE)
                return 0;

        memset(res, 0, sizeof(*res));
        res->sr_slotid = NFS4_MAX_SLOT_TABLE;
        tbl = &session->fc_slot_table;

        spin_lock(&tbl->slot_tbl_lock);
        slotid = nfs4_find_slot(tbl, task);
        if (slotid == NFS4_MAX_SLOT_TABLE) {
                rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
                spin_unlock(&tbl->slot_tbl_lock);
                dprintk("<-- %s: no free slots\n", __func__);
                return -EAGAIN;
        }
        spin_unlock(&tbl->slot_tbl_lock);

        slot = tbl->slots + slotid;
        args->sa_session = session;
        args->sa_slotid = slotid;
        args->sa_cache_this = cache_reply;

        dprintk("<-- %s slotid=%d seqid=%d\n", __func__, slotid, slot->seq_nr);

        res->sr_session = session;
        res->sr_slotid = slotid;
        res->sr_renewal_time = jiffies;
        /*
         * sr_status is only set in decode_sequence, and so will remain
         * set to 1 if an rpc level failure occurs.
         */
        res->sr_status = 1;
        return 0;
}

int nfs4_setup_sequence(struct nfs_client *clp,
                        struct nfs4_sequence_args *args,
                        struct nfs4_sequence_res *res,
                        int cache_reply,
                        struct rpc_task *task)
{
        int ret = 0;

        dprintk("--> %s clp %p session %p sr_slotid %d\n",
                __func__, clp, clp->cl_session, res->sr_slotid);

        if (!nfs4_has_session(clp))
                goto out;
        ret = nfs41_setup_sequence(clp->cl_session, args, res, cache_reply,
                                   task);
        if (ret != -EAGAIN) {
                /* terminate rpc task */
                task->tk_status = ret;
                task->tk_action = NULL;
        }
out:
        dprintk("<-- %s status=%d\n", __func__, ret);
        return ret;
}

struct nfs41_call_sync_data {
        struct nfs_client *clp;
        struct nfs4_sequence_args *seq_args;
        struct nfs4_sequence_res *seq_res;
        int cache_reply;
};

static void nfs41_call_sync_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs41_call_sync_data *data = calldata;

        dprintk("--> %s data->clp->cl_session %p\n", __func__,
                data->clp->cl_session);
        if (nfs4_setup_sequence(data->clp, data->seq_args,
                                data->seq_res, data->cache_reply, task))
                return;
        rpc_call_start(task);
}

static void nfs41_call_sync_done(struct rpc_task *task, void *calldata)
{
        struct nfs41_call_sync_data *data = calldata;

        nfs41_sequence_done(data->clp, data->seq_res, task->tk_status);
        nfs41_sequence_free_slot(data->clp, data->seq_res);
}

struct rpc_call_ops nfs41_call_sync_ops = {
        .rpc_call_prepare = nfs41_call_sync_prepare,
        .rpc_call_done = nfs41_call_sync_done,
};

static int nfs4_call_sync_sequence(struct nfs_client *clp,
                                   struct rpc_clnt *clnt,
                                   struct rpc_message *msg,
                                   struct nfs4_sequence_args *args,
                                   struct nfs4_sequence_res *res,
                                   int cache_reply)
{
        int ret;
        struct rpc_task *task;
        struct nfs41_call_sync_data data = {
                .clp = clp,
                .seq_args = args,
                .seq_res = res,
                .cache_reply = cache_reply,
        };
        struct rpc_task_setup task_setup = {
                .rpc_client = clnt,
                .rpc_message = msg,
                .callback_ops = &nfs41_call_sync_ops,
                .callback_data = &data
        };

        res->sr_slotid = NFS4_MAX_SLOT_TABLE;
        task = rpc_run_task(&task_setup);
        if (IS_ERR(task))
                ret = PTR_ERR(task);
        else {
                ret = task->tk_status;
                rpc_put_task(task);
        }
        return ret;
}

int _nfs4_call_sync_session(struct nfs_server *server,
                            struct rpc_message *msg,
                            struct nfs4_sequence_args *args,
                            struct nfs4_sequence_res *res,
                            int cache_reply)
{
        return nfs4_call_sync_sequence(server->nfs_client, server->client,
                                       msg, args, res, cache_reply);
}

#endif /* CONFIG_NFS_V4_1 */

int _nfs4_call_sync(struct nfs_server *server,
                    struct rpc_message *msg,
                    struct nfs4_sequence_args *args,
                    struct nfs4_sequence_res *res,
                    int cache_reply)
{
        args->sa_session = res->sr_session = NULL;
        return rpc_call_sync(server->client, msg, 0);
}

#define nfs4_call_sync(server, msg, args, res, cache_reply) \
        (server)->nfs_client->cl_call_sync((server), (msg), &(args)->seq_args, \
                        &(res)->seq_res, (cache_reply))

static void nfs4_sequence_done(const struct nfs_server *server,
                               struct nfs4_sequence_res *res, int rpc_status)
{
#ifdef CONFIG_NFS_V4_1
        if (nfs4_has_session(server->nfs_client))
                nfs41_sequence_done(server->nfs_client, res, rpc_status);
#endif /* CONFIG_NFS_V4_1 */
}

/* no restart, therefore free slot here */
static void nfs4_sequence_done_free_slot(const struct nfs_server *server,
                                         struct nfs4_sequence_res *res,
                                         int rpc_status)
{
        nfs4_sequence_done(server, res, rpc_status);
        nfs4_sequence_free_slot(server->nfs_client, res);
}

static void update_changeattr(struct inode *dir, struct nfs4_change_info *cinfo)
{
        struct nfs_inode *nfsi = NFS_I(dir);

        spin_lock(&dir->i_lock);
        nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA;
        if (!cinfo->atomic || cinfo->before != nfsi->change_attr)
                nfs_force_lookup_revalidate(dir);
        nfsi->change_attr = cinfo->after;
        spin_unlock(&dir->i_lock);
}

struct nfs4_opendata {
        struct kref kref;
        struct nfs_openargs o_arg;
        struct nfs_openres o_res;
        struct nfs_open_confirmargs c_arg;
        struct nfs_open_confirmres c_res;
        struct nfs_fattr f_attr;
        struct nfs_fattr dir_attr;
        struct path path;
        struct dentry *dir;
        struct nfs4_state_owner *owner;
        struct nfs4_state *state;
        struct iattr attrs;
        unsigned long timestamp;
        unsigned int rpc_done : 1;
        int rpc_status;
        int cancelled;
};


static void nfs4_init_opendata_res(struct nfs4_opendata *p)
{
        p->o_res.f_attr = &p->f_attr;
        p->o_res.dir_attr = &p->dir_attr;
        p->o_res.seqid = p->o_arg.seqid;
        p->c_res.seqid = p->c_arg.seqid;
        p->o_res.server = p->o_arg.server;
        nfs_fattr_init(&p->f_attr);
        nfs_fattr_init(&p->dir_attr);
}

static struct nfs4_opendata *nfs4_opendata_alloc(struct path *path,
                struct nfs4_state_owner *sp, fmode_t fmode, int flags,
                const struct iattr *attrs)
{
        struct dentry *parent = dget_parent(path->dentry);
        struct inode *dir = parent->d_inode;
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs4_opendata *p;

        p = kzalloc(sizeof(*p), GFP_KERNEL);
        if (p == NULL)
                goto err;
        p->o_arg.seqid = nfs_alloc_seqid(&sp->so_seqid);
        if (p->o_arg.seqid == NULL)
                goto err_free;
        p->path.mnt = mntget(path->mnt);
        p->path.dentry = dget(path->dentry);
        p->dir = parent;
        p->owner = sp;
        atomic_inc(&sp->so_count);
        p->o_arg.fh = NFS_FH(dir);
        p->o_arg.open_flags = flags;
        p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
        p->o_arg.clientid = server->nfs_client->cl_clientid;
        p->o_arg.id = sp->so_owner_id.id;
        p->o_arg.name = &p->path.dentry->d_name;
        p->o_arg.server = server;
        p->o_arg.bitmask = server->attr_bitmask;
        p->o_arg.claim = NFS4_OPEN_CLAIM_NULL;
        p->o_res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        if (flags & O_EXCL) {
                u32 *s = (u32 *) p->o_arg.u.verifier.data;
                s[0] = jiffies;
                s[1] = current->pid;
        } else if (flags & O_CREAT) {
                p->o_arg.u.attrs = &p->attrs;
                memcpy(&p->attrs, attrs, sizeof(p->attrs));
        }
        p->c_arg.fh = &p->o_res.fh;
        p->c_arg.stateid = &p->o_res.stateid;
        p->c_arg.seqid = p->o_arg.seqid;
        nfs4_init_opendata_res(p);
        kref_init(&p->kref);
        return p;
err_free:
        kfree(p);
err:
        dput(parent);
        return NULL;
}

static void nfs4_opendata_free(struct kref *kref)
{
        struct nfs4_opendata *p = container_of(kref,
                        struct nfs4_opendata, kref);

        nfs_free_seqid(p->o_arg.seqid);
        if (p->state != NULL)
                nfs4_put_open_state(p->state);
        nfs4_put_state_owner(p->owner);
        dput(p->dir);
        path_put(&p->path);
        kfree(p);
}

static void nfs4_opendata_put(struct nfs4_opendata *p)
{
        if (p != NULL)
                kref_put(&p->kref, nfs4_opendata_free);
}

static int nfs4_wait_for_completion_rpc_task(struct rpc_task *task)
{
        int ret;

        ret = rpc_wait_for_completion_task(task);
        return ret;
}

static int can_open_cached(struct nfs4_state *state, fmode_t mode, int open_mode)
{
        int ret = 0;

        if (open_mode & O_EXCL)
                goto out;
        switch (mode & (FMODE_READ|FMODE_WRITE)) {
                case FMODE_READ:
                        ret |= test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0;
                        break;
                case FMODE_WRITE:
                        ret |= test_bit(NFS_O_WRONLY_STATE, &state->flags) != 0;
                        break;
                case FMODE_READ|FMODE_WRITE:
                        ret |= test_bit(NFS_O_RDWR_STATE, &state->flags) != 0;
        }
out:
        return ret;
}

static int can_open_delegated(struct nfs_delegation *delegation, fmode_t fmode)
{
        if ((delegation->type & fmode) != fmode)
                return 0;
        if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags))
                return 0;
        nfs_mark_delegation_referenced(delegation);
        return 1;
}

static void update_open_stateflags(struct nfs4_state *state, fmode_t fmode)
{
        switch (fmode) {
                case FMODE_WRITE:
                        state->n_wronly++;
                        break;
                case FMODE_READ:
                        state->n_rdonly++;
                        break;
                case FMODE_READ|FMODE_WRITE:
                        state->n_rdwr++;
        }
        nfs4_state_set_mode_locked(state, state->state | fmode);
}

static void nfs_set_open_stateid_locked(struct nfs4_state *state, nfs4_stateid *stateid, fmode_t fmode)
{
        if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                memcpy(state->stateid.data, stateid->data, sizeof(state->stateid.data));
        memcpy(state->open_stateid.data, stateid->data, sizeof(state->open_stateid.data));
        switch (fmode) {
                case FMODE_READ:
                        set_bit(NFS_O_RDONLY_STATE, &state->flags);
                        break;
                case FMODE_WRITE:
                        set_bit(NFS_O_WRONLY_STATE, &state->flags);
                        break;
                case FMODE_READ|FMODE_WRITE:
                        set_bit(NFS_O_RDWR_STATE, &state->flags);
        }
}

static void nfs_set_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid, fmode_t fmode)
{
        write_seqlock(&state->seqlock);
        nfs_set_open_stateid_locked(state, stateid, fmode);
        write_sequnlock(&state->seqlock);
}

static void __update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_stateid, const nfs4_stateid *deleg_stateid, fmode_t fmode)
{
        /*
         * Protect the call to nfs4_state_set_mode_locked and
         * serialise the stateid update
         */
        write_seqlock(&state->seqlock);
        if (deleg_stateid != NULL) {
                memcpy(state->stateid.data, deleg_stateid->data, sizeof(state->stateid.data));
                set_bit(NFS_DELEGATED_STATE, &state->flags);
        }
        if (open_stateid != NULL)
                nfs_set_open_stateid_locked(state, open_stateid, fmode);
        write_sequnlock(&state->seqlock);
        spin_lock(&state->owner->so_lock);
        update_open_stateflags(state, fmode);
        spin_unlock(&state->owner->so_lock);
}

static int update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_stateid, nfs4_stateid *delegation, fmode_t fmode)
{
        struct nfs_inode *nfsi = NFS_I(state->inode);
        struct nfs_delegation *deleg_cur;
        int ret = 0;

        fmode &= (FMODE_READ|FMODE_WRITE);

        rcu_read_lock();
        deleg_cur = rcu_dereference(nfsi->delegation);
        if (deleg_cur == NULL)
                goto no_delegation;

        spin_lock(&deleg_cur->lock);
        if (nfsi->delegation != deleg_cur ||
            (deleg_cur->type & fmode) != fmode)
                goto no_delegation_unlock;

        if (delegation == NULL)
                delegation = &deleg_cur->stateid;
        else if (memcmp(deleg_cur->stateid.data, delegation->data, NFS4_STATEID_SIZE) != 0)
                goto no_delegation_unlock;

        nfs_mark_delegation_referenced(deleg_cur);
        __update_open_stateid(state, open_stateid, &deleg_cur->stateid, fmode);
        ret = 1;
no_delegation_unlock:
        spin_unlock(&deleg_cur->lock);
no_delegation:
        rcu_read_unlock();

        if (!ret && open_stateid != NULL) {
                __update_open_stateid(state, open_stateid, NULL, fmode);
                ret = 1;
        }

        return ret;
}


static void nfs4_return_incompatible_delegation(struct inode *inode, fmode_t fmode)
{
        struct nfs_delegation *delegation;

        rcu_read_lock();
        delegation = rcu_dereference(NFS_I(inode)->delegation);
        if (delegation == NULL || (delegation->type & fmode) == fmode) {
                rcu_read_unlock();
                return;
        }
        rcu_read_unlock();
        nfs_inode_return_delegation(inode);
}

static struct nfs4_state *nfs4_try_open_cached(struct nfs4_opendata *opendata)
{
        struct nfs4_state *state = opendata->state;
        struct nfs_inode *nfsi = NFS_I(state->inode);
        struct nfs_delegation *delegation;
        int open_mode = opendata->o_arg.open_flags & O_EXCL;
        fmode_t fmode = opendata->o_arg.fmode;
        nfs4_stateid stateid;
        int ret = -EAGAIN;

        for (;;) {
                if (can_open_cached(state, fmode, open_mode)) {
                        spin_lock(&state->owner->so_lock);
                        if (can_open_cached(state, fmode, open_mode)) {
                                update_open_stateflags(state, fmode);
                                spin_unlock(&state->owner->so_lock);
                                goto out_return_state;
                        }
                        spin_unlock(&state->owner->so_lock);
                }
                rcu_read_lock();
                delegation = rcu_dereference(nfsi->delegation);
                if (delegation == NULL ||
                    !can_open_delegated(delegation, fmode)) {
                        rcu_read_unlock();
                        break;
                }
                /* Save the delegation */
                memcpy(stateid.data, delegation->stateid.data, sizeof(stateid.data));
                rcu_read_unlock();
                ret = nfs_may_open(state->inode, state->owner->so_cred, open_mode);
                if (ret != 0)
                        goto out;
                ret = -EAGAIN;

                /* Try to update the stateid using the delegation */
                if (update_open_stateid(state, NULL, &stateid, fmode))
                        goto out_return_state;
        }
out:
        return ERR_PTR(ret);
out_return_state:
        atomic_inc(&state->count);
        return state;
}

static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
{
        struct inode *inode;
        struct nfs4_state *state = NULL;
        struct nfs_delegation *delegation;
        int ret;

        if (!data->rpc_done) {
                state = nfs4_try_open_cached(data);
                goto out;
        }

        ret = -EAGAIN;
        if (!(data->f_attr.valid & NFS_ATTR_FATTR))
                goto err;
        inode = nfs_fhget(data->dir->d_sb, &data->o_res.fh, &data->f_attr);
        ret = PTR_ERR(inode);
        if (IS_ERR(inode))
                goto err;
        ret = -ENOMEM;
        state = nfs4_get_open_state(inode, data->owner);
        if (state == NULL)
                goto err_put_inode;
        if (data->o_res.delegation_type != 0) {
                int delegation_flags = 0;

                rcu_read_lock();
                delegation = rcu_dereference(NFS_I(inode)->delegation);
                if (delegation)
                        delegation_flags = delegation->flags;
                rcu_read_unlock();
                if ((delegation_flags & 1UL<<NFS_DELEGATION_NEED_RECLAIM) == 0)
                        nfs_inode_set_delegation(state->inode,
                                        data->owner->so_cred,
                                        &data->o_res);
                else
                        nfs_inode_reclaim_delegation(state->inode,
                                        data->owner->so_cred,
                                        &data->o_res);
        }

        update_open_stateid(state, &data->o_res.stateid, NULL,
                        data->o_arg.fmode);
        iput(inode);
out:
        return state;
err_put_inode:
        iput(inode);
err:
        return ERR_PTR(ret);
}

static struct nfs_open_context *nfs4_state_find_open_context(struct nfs4_state *state)
{
        struct nfs_inode *nfsi = NFS_I(state->inode);
        struct nfs_open_context *ctx;

        spin_lock(&state->inode->i_lock);
        list_for_each_entry(ctx, &nfsi->open_files, list) {
                if (ctx->state != state)
                        continue;
                get_nfs_open_context(ctx);
                spin_unlock(&state->inode->i_lock);
                return ctx;
        }
        spin_unlock(&state->inode->i_lock);
        return ERR_PTR(-ENOENT);
}

static struct nfs4_opendata *nfs4_open_recoverdata_alloc(struct nfs_open_context *ctx, struct nfs4_state *state)
{
        struct nfs4_opendata *opendata;

        opendata = nfs4_opendata_alloc(&ctx->path, state->owner, 0, 0, NULL);
        if (opendata == NULL)
                return ERR_PTR(-ENOMEM);
        opendata->state = state;
        atomic_inc(&state->count);
        return opendata;
}

static int nfs4_open_recover_helper(struct nfs4_opendata *opendata, fmode_t fmode, struct nfs4_state **res)
{
        struct nfs4_state *newstate;
        int ret;

        opendata->o_arg.open_flags = 0;
        opendata->o_arg.fmode = fmode;
        memset(&opendata->o_res, 0, sizeof(opendata->o_res));
        memset(&opendata->c_res, 0, sizeof(opendata->c_res));
        nfs4_init_opendata_res(opendata);
        ret = _nfs4_proc_open(opendata);
        if (ret != 0)
                return ret; 
        newstate = nfs4_opendata_to_nfs4_state(opendata);
        if (IS_ERR(newstate))
                return PTR_ERR(newstate);
        nfs4_close_state(&opendata->path, newstate, fmode);
        *res = newstate;
        return 0;
}

static int nfs4_open_recover(struct nfs4_opendata *opendata, struct nfs4_state *state)
{
        struct nfs4_state *newstate;
        int ret;

        /* memory barrier prior to reading state->n_* */
        clear_bit(NFS_DELEGATED_STATE, &state->flags);
        smp_rmb();
        if (state->n_rdwr != 0) {
                ret = nfs4_open_recover_helper(opendata, FMODE_READ|FMODE_WRITE, &newstate);
                if (ret != 0)
                        return ret;
                if (newstate != state)
                        return -ESTALE;
        }
        if (state->n_wronly != 0) {
                ret = nfs4_open_recover_helper(opendata, FMODE_WRITE, &newstate);
                if (ret != 0)
                        return ret;
                if (newstate != state)
                        return -ESTALE;
        }
        if (state->n_rdonly != 0) {
                ret = nfs4_open_recover_helper(opendata, FMODE_READ, &newstate);
                if (ret != 0)
                        return ret;
                if (newstate != state)
                        return -ESTALE;
        }
        /*
         * We may have performed cached opens for all three recoveries.
         * Check if we need to update the current stateid.
         */
        if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0 &&
            memcmp(state->stateid.data, state->open_stateid.data, sizeof(state->stateid.data)) != 0) {
                write_seqlock(&state->seqlock);
                if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                        memcpy(state->stateid.data, state->open_stateid.data, sizeof(state->stateid.data));
                write_sequnlock(&state->seqlock);
        }
        return 0;
}

/*
 * OPEN_RECLAIM:
 *      reclaim state on the server after a reboot.
 */
static int _nfs4_do_open_reclaim(struct nfs_open_context *ctx, struct nfs4_state *state)
{
        struct nfs_delegation *delegation;
        struct nfs4_opendata *opendata;
        fmode_t delegation_type = 0;
        int status;

        opendata = nfs4_open_recoverdata_alloc(ctx, state);
        if (IS_ERR(opendata))
                return PTR_ERR(opendata);
        opendata->o_arg.claim = NFS4_OPEN_CLAIM_PREVIOUS;
        opendata->o_arg.fh = NFS_FH(state->inode);
        rcu_read_lock();
        delegation = rcu_dereference(NFS_I(state->inode)->delegation);
        if (delegation != NULL && test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) != 0)
                delegation_type = delegation->type;
        rcu_read_unlock();
        opendata->o_arg.u.delegation_type = delegation_type;
        status = nfs4_open_recover(opendata, state);
        nfs4_opendata_put(opendata);
        return status;
}

static int nfs4_do_open_reclaim(struct nfs_open_context *ctx, struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_do_open_reclaim(ctx, state);
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int nfs4_open_reclaim(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        struct nfs_open_context *ctx;
        int ret;

        ctx = nfs4_state_find_open_context(state);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);
        ret = nfs4_do_open_reclaim(ctx, state);
        put_nfs_open_context(ctx);
        return ret;
}

static int _nfs4_open_delegation_recall(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
{
        struct nfs4_opendata *opendata;
        int ret;

        opendata = nfs4_open_recoverdata_alloc(ctx, state);
        if (IS_ERR(opendata))
                return PTR_ERR(opendata);
        opendata->o_arg.claim = NFS4_OPEN_CLAIM_DELEGATE_CUR;
        memcpy(opendata->o_arg.u.delegation.data, stateid->data,
                        sizeof(opendata->o_arg.u.delegation.data));
        ret = nfs4_open_recover(opendata, state);
        nfs4_opendata_put(opendata);
        return ret;
}

int nfs4_open_delegation_recall(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
{
        struct nfs4_exception exception = { };
        struct nfs_server *server = NFS_SERVER(state->inode);
        int err;
        do {
                err = _nfs4_open_delegation_recall(ctx, state, stateid);
                switch (err) {
                        case 0:
                                return err;
                        case -NFS4ERR_STALE_CLIENTID:
                        case -NFS4ERR_STALE_STATEID:
                        case -NFS4ERR_EXPIRED:
                                /* Don't recall a delegation if it was lost */
                                nfs4_schedule_state_recovery(server->nfs_client);
                                return err;
                }
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static void nfs4_open_confirm_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_opendata *data = calldata;

        data->rpc_status = task->tk_status;
        if (RPC_ASSASSINATED(task))
                return;
        if (data->rpc_status == 0) {
                memcpy(data->o_res.stateid.data, data->c_res.stateid.data,
                                sizeof(data->o_res.stateid.data));
                nfs_confirm_seqid(&data->owner->so_seqid, 0);
                renew_lease(data->o_res.server, data->timestamp);
                data->rpc_done = 1;
        }
}

static void nfs4_open_confirm_release(void *calldata)
{
        struct nfs4_opendata *data = calldata;
        struct nfs4_state *state = NULL;

        /* If this request hasn't been cancelled, do nothing */
        if (data->cancelled == 0)
                goto out_free;
        /* In case of error, no cleanup! */
        if (!data->rpc_done)
                goto out_free;
        state = nfs4_opendata_to_nfs4_state(data);
        if (!IS_ERR(state))
                nfs4_close_state(&data->path, state, data->o_arg.fmode);
out_free:
        nfs4_opendata_put(data);
}

static const struct rpc_call_ops nfs4_open_confirm_ops = {
        .rpc_call_done = nfs4_open_confirm_done,
        .rpc_release = nfs4_open_confirm_release,
};

/*
 * Note: On error, nfs4_proc_open_confirm will free the struct nfs4_opendata
 */
static int _nfs4_proc_open_confirm(struct nfs4_opendata *data)
{
        struct nfs_server *server = NFS_SERVER(data->dir->d_inode);
        struct rpc_task *task;
        struct  rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_CONFIRM],
                .rpc_argp = &data->c_arg,
                .rpc_resp = &data->c_res,
                .rpc_cred = data->owner->so_cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_open_confirm_ops,
                .callback_data = data,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };
        int status;

        kref_get(&data->kref);
        data->rpc_done = 0;
        data->rpc_status = 0;
        data->timestamp = jiffies;
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = nfs4_wait_for_completion_rpc_task(task);
        if (status != 0) {
                data->cancelled = 1;
                smp_wmb();
        } else
                status = data->rpc_status;
        rpc_put_task(task);
        return status;
}

static void nfs4_open_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_opendata *data = calldata;
        struct nfs4_state_owner *sp = data->owner;

        if (nfs_wait_on_sequence(data->o_arg.seqid, task) != 0)
                return;
        /*
         * Check if we still need to send an OPEN call, or if we can use
         * a delegation instead.
         */
        if (data->state != NULL) {
                struct nfs_delegation *delegation;

                if (can_open_cached(data->state, data->o_arg.fmode, data->o_arg.open_flags))
                        goto out_no_action;
                rcu_read_lock();
                delegation = rcu_dereference(NFS_I(data->state->inode)->delegation);
                if (delegation != NULL &&
                    test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0) {
                        rcu_read_unlock();
                        goto out_no_action;
                }
                rcu_read_unlock();
        }
        /* Update sequence id. */
        data->o_arg.id = sp->so_owner_id.id;
        data->o_arg.clientid = sp->so_client->cl_clientid;
        if (data->o_arg.claim == NFS4_OPEN_CLAIM_PREVIOUS) {
                task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_NOATTR];
                nfs_copy_fh(&data->o_res.fh, data->o_arg.fh);
        }
        data->timestamp = jiffies;
        if (nfs4_setup_sequence(data->o_arg.server->nfs_client,
                                &data->o_arg.seq_args,
                                &data->o_res.seq_res, 1, task))
                return;
        rpc_call_start(task);
        return;
out_no_action:
        task->tk_action = NULL;

}

static void nfs4_open_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_opendata *data = calldata;

        data->rpc_status = task->tk_status;

        nfs4_sequence_done_free_slot(data->o_arg.server, &data->o_res.seq_res,
                                     task->tk_status);

        if (RPC_ASSASSINATED(task))
                return;
        if (task->tk_status == 0) {
                switch (data->o_res.f_attr->mode & S_IFMT) {
                        case S_IFREG:
                                break;
                        case S_IFLNK:
                                data->rpc_status = -ELOOP;
                                break;
                        case S_IFDIR:
                                data->rpc_status = -EISDIR;
                                break;
                        default:
                                data->rpc_status = -ENOTDIR;
                }
                renew_lease(data->o_res.server, data->timestamp);
                if (!(data->o_res.rflags & NFS4_OPEN_RESULT_CONFIRM))
                        nfs_confirm_seqid(&data->owner->so_seqid, 0);
        }
        data->rpc_done = 1;
}

static void nfs4_open_release(void *calldata)
{
        struct nfs4_opendata *data = calldata;
        struct nfs4_state *state = NULL;

        /* If this request hasn't been cancelled, do nothing */
        if (data->cancelled == 0)
                goto out_free;
        /* In case of error, no cleanup! */
        if (data->rpc_status != 0 || !data->rpc_done)
                goto out_free;
        /* In case we need an open_confirm, no cleanup! */
        if (data->o_res.rflags & NFS4_OPEN_RESULT_CONFIRM)
                goto out_free;
        state = nfs4_opendata_to_nfs4_state(data);
        if (!IS_ERR(state))
                nfs4_close_state(&data->path, state, data->o_arg.fmode);
out_free:
        nfs4_opendata_put(data);
}

static const struct rpc_call_ops nfs4_open_ops = {
        .rpc_call_prepare = nfs4_open_prepare,
        .rpc_call_done = nfs4_open_done,
        .rpc_release = nfs4_open_release,
};

/*
 * Note: On error, nfs4_proc_open will free the struct nfs4_opendata
 */
static int _nfs4_proc_open(struct nfs4_opendata *data)
{
        struct inode *dir = data->dir->d_inode;
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_openargs *o_arg = &data->o_arg;
        struct nfs_openres *o_res = &data->o_res;
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN],
                .rpc_argp = o_arg,
                .rpc_resp = o_res,
                .rpc_cred = data->owner->so_cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_open_ops,
                .callback_data = data,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };
        int status;

        kref_get(&data->kref);
        data->rpc_done = 0;
        data->rpc_status = 0;
        data->cancelled = 0;
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = nfs4_wait_for_completion_rpc_task(task);
        if (status != 0) {
                data->cancelled = 1;
                smp_wmb();
        } else
                status = data->rpc_status;
        rpc_put_task(task);
        if (status != 0 || !data->rpc_done)
                return status;

        if (o_res->fh.size == 0)
                _nfs4_proc_lookup(dir, o_arg->name, &o_res->fh, o_res->f_attr);

        if (o_arg->open_flags & O_CREAT) {
                update_changeattr(dir, &o_res->cinfo);
                nfs_post_op_update_inode(dir, o_res->dir_attr);
        } else
                nfs_refresh_inode(dir, o_res->dir_attr);
        if(o_res->rflags & NFS4_OPEN_RESULT_CONFIRM) {
                status = _nfs4_proc_open_confirm(data);
                if (status != 0)
                        return status;
        }
        if (!(o_res->f_attr->valid & NFS_ATTR_FATTR))
                _nfs4_proc_getattr(server, &o_res->fh, o_res->f_attr);
        return 0;
}

static int nfs4_recover_expired_lease(struct nfs_server *server)
{
        struct nfs_client *clp = server->nfs_client;
        int ret;

        for (;;) {
                ret = nfs4_wait_clnt_recover(clp);
                if (ret != 0)
                        return ret;
                if (!test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) &&
                    !test_bit(NFS4CLNT_CHECK_LEASE,&clp->cl_state))
                        break;
                nfs4_schedule_state_recovery(clp);
        }
        return 0;
}

/*
 * OPEN_EXPIRED:
 *      reclaim state on the server after a network partition.
 *      Assumes caller holds the appropriate lock
 */
static int _nfs4_open_expired(struct nfs_open_context *ctx, struct nfs4_state *state)
{
        struct nfs4_opendata *opendata;
        int ret;

        opendata = nfs4_open_recoverdata_alloc(ctx, state);
        if (IS_ERR(opendata))
                return PTR_ERR(opendata);
        ret = nfs4_open_recover(opendata, state);
        if (ret == -ESTALE)
                d_drop(ctx->path.dentry);
        nfs4_opendata_put(opendata);
        return ret;
}

static inline int nfs4_do_open_expired(struct nfs_open_context *ctx, struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = { };
        int err;

        do {
                err = _nfs4_open_expired(ctx, state);
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int nfs4_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        struct nfs_open_context *ctx;
        int ret;

        ctx = nfs4_state_find_open_context(state);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);
        ret = nfs4_do_open_expired(ctx, state);
        put_nfs_open_context(ctx);
        return ret;
}

/*
 * on an EXCLUSIVE create, the server should send back a bitmask with FATTR4-*
 * fields corresponding to attributes that were used to store the verifier.
 * Make sure we clobber those fields in the later setattr call
 */
static inline void nfs4_exclusive_attrset(struct nfs4_opendata *opendata, struct iattr *sattr)
{
        if ((opendata->o_res.attrset[1] & FATTR4_WORD1_TIME_ACCESS) &&
            !(sattr->ia_valid & ATTR_ATIME_SET))
                sattr->ia_valid |= ATTR_ATIME;

        if ((opendata->o_res.attrset[1] & FATTR4_WORD1_TIME_MODIFY) &&
            !(sattr->ia_valid & ATTR_MTIME_SET))
                sattr->ia_valid |= ATTR_MTIME;
}

/*
 * Returns a referenced nfs4_state
 */
static int _nfs4_do_open(struct inode *dir, struct path *path, fmode_t fmode, int flags, struct iattr *sattr, struct rpc_cred *cred, struct nfs4_state **res)
{
        struct nfs4_state_owner  *sp;
        struct nfs4_state     *state = NULL;
        struct nfs_server       *server = NFS_SERVER(dir);
        struct nfs4_opendata *opendata;
        int status;

        /* Protect against reboot recovery conflicts */
        status = -ENOMEM;
        if (!(sp = nfs4_get_state_owner(server, cred))) {
                dprintk("nfs4_do_open: nfs4_get_state_owner failed!\n");
                goto out_err;
        }
        status = nfs4_recover_expired_lease(server);
        if (status != 0)
                goto err_put_state_owner;
        if (path->dentry->d_inode != NULL)
                nfs4_return_incompatible_delegation(path->dentry->d_inode, fmode);
        status = -ENOMEM;
        opendata = nfs4_opendata_alloc(path, sp, fmode, flags, sattr);
        if (opendata == NULL)
                goto err_put_state_owner;

        if (path->dentry->d_inode != NULL)
                opendata->state = nfs4_get_open_state(path->dentry->d_inode, sp);

        status = _nfs4_proc_open(opendata);
        if (status != 0)
                goto err_opendata_put;

        if (opendata->o_arg.open_flags & O_EXCL)
                nfs4_exclusive_attrset(opendata, sattr);

        state = nfs4_opendata_to_nfs4_state(opendata);
        status = PTR_ERR(state);
        if (IS_ERR(state))
                goto err_opendata_put;
        nfs4_opendata_put(opendata);
        nfs4_put_state_owner(sp);
        *res = state;
        return 0;
err_opendata_put:
        nfs4_opendata_put(opendata);
err_put_state_owner:
        nfs4_put_state_owner(sp);
out_err:
        *res = NULL;
        return status;
}


static struct nfs4_state *nfs4_do_open(struct inode *dir, struct path *path, fmode_t fmode, int flags, struct iattr *sattr, struct rpc_cred *cred)
{
        struct nfs4_exception exception = { };
        struct nfs4_state *res;
        int status;

        do {
                status = _nfs4_do_open(dir, path, fmode, flags, sattr, cred, &res);
                if (status == 0)
                        break;
                /* NOTE: BAD_SEQID means the server and client disagree about the
                 * book-keeping w.r.t. state-changing operations
                 * (OPEN/CLOSE/LOCK/LOCKU...)
                 * It is actually a sign of a bug on the client or on the server.
                 *
                 * If we receive a BAD_SEQID error in the particular case of
                 * doing an OPEN, we assume that nfs_increment_open_seqid() will
                 * have unhashed the old state_owner for us, and that we can
                 * therefore safely retry using a new one. We should still warn
                 * the user though...
                 */
                if (status == -NFS4ERR_BAD_SEQID) {
                        printk(KERN_WARNING "NFS: v4 server %s "
                                        " returned a bad sequence-id error!\n",
                                        NFS_SERVER(dir)->nfs_client->cl_hostname);
                        exception.retry = 1;
                        continue;
                }
                /*
                 * BAD_STATEID on OPEN means that the server cancelled our
                 * state before it received the OPEN_CONFIRM.
                 * Recover by retrying the request as per the discussion
                 * on Page 181 of RFC3530.
                 */
                if (status == -NFS4ERR_BAD_STATEID) {
                        exception.retry = 1;
                        continue;
                }
                if (status == -EAGAIN) {
                        /* We must have found a delegation */
                        exception.retry = 1;
                        continue;
                }
                res = ERR_PTR(nfs4_handle_exception(NFS_SERVER(dir),
                                        status, &exception));
        } while (exception.retry);
        return res;
}

static int _nfs4_do_setattr(struct inode *inode, struct rpc_cred *cred,
                            struct nfs_fattr *fattr, struct iattr *sattr,
                            struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_setattrargs  arg = {
                .fh             = NFS_FH(inode),
                .iap            = sattr,
                .server         = server,
                .bitmask = server->attr_bitmask,
        };
        struct nfs_setattrres  res = {
                .fattr          = fattr,
                .server         = server,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_SETATTR],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
                .rpc_cred       = cred,
        };
        unsigned long timestamp = jiffies;
        int status;

        nfs_fattr_init(fattr);

        if (nfs4_copy_delegation_stateid(&arg.stateid, inode)) {
                /* Use that stateid */
        } else if (state != NULL) {
                nfs4_copy_stateid(&arg.stateid, state, current->files);
        } else
                memcpy(&arg.stateid, &zero_stateid, sizeof(arg.stateid));

        status = nfs4_call_sync(server, &msg, &arg, &res, 1);
        if (status == 0 && state != NULL)
                renew_lease(server, timestamp);
        return status;
}

static int nfs4_do_setattr(struct inode *inode, struct rpc_cred *cred,
                           struct nfs_fattr *fattr, struct iattr *sattr,
                           struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(server,
                                _nfs4_do_setattr(inode, cred, fattr, sattr, state),
                                &exception);
        } while (exception.retry);
        return err;
}

struct nfs4_closedata {
        struct path path;
        struct inode *inode;
        struct nfs4_state *state;
        struct nfs_closeargs arg;
        struct nfs_closeres res;
        struct nfs_fattr fattr;
        unsigned long timestamp;
};

static void nfs4_free_closedata(void *data)
{
        struct nfs4_closedata *calldata = data;
        struct nfs4_state_owner *sp = calldata->state->owner;

        nfs4_put_open_state(calldata->state);
        nfs_free_seqid(calldata->arg.seqid);
        nfs4_put_state_owner(sp);
        path_put(&calldata->path);
        kfree(calldata);
}

static void nfs4_close_done(struct rpc_task *task, void *data)
{
        struct nfs4_closedata *calldata = data;
        struct nfs4_state *state = calldata->state;
        struct nfs_server *server = NFS_SERVER(calldata->inode);

        nfs4_sequence_done(server, &calldata->res.seq_res, task->tk_status);
        if (RPC_ASSASSINATED(task))
                return;
        /* hmm. we are done with the inode, and in the process of freeing
         * the state_owner. we keep this around to process errors
         */
        switch (task->tk_status) {
                case 0:
                        nfs_set_open_stateid(state, &calldata->res.stateid, 0);
                        renew_lease(server, calldata->timestamp);
                        break;
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_OLD_STATEID:
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_EXPIRED:
                        if (calldata->arg.fmode == 0)
                                break;
                default:
                        if (nfs4_async_handle_error(task, server, state) == -EAGAIN) {
                                nfs4_restart_rpc(task, server->nfs_client);
                                return;
                        }
        }
        nfs4_sequence_free_slot(server->nfs_client, &calldata->res.seq_res);
        nfs_refresh_inode(calldata->inode, calldata->res.fattr);
}

static void nfs4_close_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_closedata *calldata = data;
        struct nfs4_state *state = calldata->state;
        int clear_rd, clear_wr, clear_rdwr;

        if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)
                return;

        clear_rd = clear_wr = clear_rdwr = 0;
        spin_lock(&state->owner->so_lock);
        /* Calculate the change in open mode */
        if (state->n_rdwr == 0) {
                if (state->n_rdonly == 0) {
                        clear_rd |= test_and_clear_bit(NFS_O_RDONLY_STATE, &state->flags);
                        clear_rdwr |= test_and_clear_bit(NFS_O_RDWR_STATE, &state->flags);
                }
                if (state->n_wronly == 0) {
                        clear_wr |= test_and_clear_bit(NFS_O_WRONLY_STATE, &state->flags);
                        clear_rdwr |= test_and_clear_bit(NFS_O_RDWR_STATE, &state->flags);
                }
        }
        spin_unlock(&state->owner->so_lock);
        if (!clear_rd && !clear_wr && !clear_rdwr) {
                /* Note: exit _without_ calling nfs4_close_done */
                task->tk_action = NULL;
                return;
        }
        nfs_fattr_init(calldata->res.fattr);
        if (test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0) {
                task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
                calldata->arg.fmode = FMODE_READ;
        } else if (test_bit(NFS_O_WRONLY_STATE, &state->flags) != 0) {
                task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
                calldata->arg.fmode = FMODE_WRITE;
        }
        calldata->timestamp = jiffies;
        if (nfs4_setup_sequence((NFS_SERVER(calldata->inode))->nfs_client,
                                &calldata->arg.seq_args, &calldata->res.seq_res,
                                1, task))
                return;
        rpc_call_start(task);
}

static const struct rpc_call_ops nfs4_close_ops = {
        .rpc_call_prepare = nfs4_close_prepare,
        .rpc_call_done = nfs4_close_done,
        .rpc_release = nfs4_free_closedata,
};

/* 
 * It is possible for data to be read/written from a mem-mapped file 
 * after the sys_close call (which hits the vfs layer as a flush).
 * This means that we can't safely call nfsv4 close on a file until 
 * the inode is cleared. This in turn means that we are not good
 * NFSv4 citizens - we do not indicate to the server to update the file's 
 * share state even when we are done with one of the three share 
 * stateid's in the inode.
 *
 * NOTE: Caller must be holding the sp->so_owner semaphore!
 */
int nfs4_do_close(struct path *path, struct nfs4_state *state, int wait)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_closedata *calldata;
        struct nfs4_state_owner *sp = state->owner;
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE],
                .rpc_cred = state->owner->so_cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_close_ops,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };
        int status = -ENOMEM;

        calldata = kzalloc(sizeof(*calldata), GFP_KERNEL);
        if (calldata == NULL)
                goto out;
        calldata->inode = state->inode;
        calldata->state = state;
        calldata->arg.fh = NFS_FH(state->inode);
        calldata->arg.stateid = &state->open_stateid;
        /* Serialization for the sequence id */
        calldata->arg.seqid = nfs_alloc_seqid(&state->owner->so_seqid);
        if (calldata->arg.seqid == NULL)
                goto out_free_calldata;
        calldata->arg.fmode = 0;
        calldata->arg.bitmask = server->cache_consistency_bitmask;
        calldata->res.fattr = &calldata->fattr;
        calldata->res.seqid = calldata->arg.seqid;
        calldata->res.server = server;
        calldata->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        calldata->path.mnt = mntget(path->mnt);
        calldata->path.dentry = dget(path->dentry);

        msg.rpc_argp = &calldata->arg,
        msg.rpc_resp = &calldata->res,
        task_setup_data.callback_data = calldata;
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = 0;
        if (wait)
                status = rpc_wait_for_completion_task(task);
        rpc_put_task(task);
        return status;
out_free_calldata:
        kfree(calldata);
out:
        nfs4_put_open_state(state);
        nfs4_put_state_owner(sp);
        return status;
}

static int nfs4_intent_set_file(struct nameidata *nd, struct path *path, struct nfs4_state *state, fmode_t fmode)
{
        struct file *filp;
        int ret;

        /* If the open_intent is for execute, we have an extra check to make */
        if (fmode & FMODE_EXEC) {
                ret = nfs_may_open(state->inode,
                                state->owner->so_cred,
                                nd->intent.open.flags);
                if (ret < 0)
                        goto out_close;
        }
        filp = lookup_instantiate_filp(nd, path->dentry, NULL);
        if (!IS_ERR(filp)) {
                struct nfs_open_context *ctx;
                ctx = nfs_file_open_context(filp);
                ctx->state = state;
                return 0;
        }
        ret = PTR_ERR(filp);
out_close:
        nfs4_close_sync(path, state, fmode & (FMODE_READ|FMODE_WRITE));
        return ret;
}

struct dentry *
nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
        struct path path = {
                .mnt = nd->path.mnt,
                .dentry = dentry,
        };
        struct dentry *parent;
        struct iattr attr;
        struct rpc_cred *cred;
        struct nfs4_state *state;
        struct dentry *res;
        fmode_t fmode = nd->intent.open.flags & (FMODE_READ | FMODE_WRITE | FMODE_EXEC);

        if (nd->flags & LOOKUP_CREATE) {
                attr.ia_mode = nd->intent.open.create_mode;
                attr.ia_valid = ATTR_MODE;
                if (!IS_POSIXACL(dir))
                        attr.ia_mode &= ~current_umask();
        } else {
                attr.ia_valid = 0;
                BUG_ON(nd->intent.open.flags & O_CREAT);
        }

        cred = rpc_lookup_cred();
        if (IS_ERR(cred))
                return (struct dentry *)cred;
        parent = dentry->d_parent;
        /* Protect against concurrent sillydeletes */
        nfs_block_sillyrename(parent);
        state = nfs4_do_open(dir, &path, fmode, nd->intent.open.flags, &attr, cred);
        put_rpccred(cred);
        if (IS_ERR(state)) {
                if (PTR_ERR(state) == -ENOENT) {
                        d_add(dentry, NULL);
                        nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
                }
                nfs_unblock_sillyrename(parent);
                return (struct dentry *)state;
        }
        res = d_add_unique(dentry, igrab(state->inode));
        if (res != NULL)
                path.dentry = res;
        nfs_set_verifier(path.dentry, nfs_save_change_attribute(dir));
        nfs_unblock_sillyrename(parent);
        nfs4_intent_set_file(nd, &path, state, fmode);
        return res;
}

int
nfs4_open_revalidate(struct inode *dir, struct dentry *dentry, int openflags, struct nameidata *nd)
{
        struct path path = {
                .mnt = nd->path.mnt,
                .dentry = dentry,
        };
        struct rpc_cred *cred;
        struct nfs4_state *state;
        fmode_t fmode = openflags & (FMODE_READ | FMODE_WRITE);

        cred = rpc_lookup_cred();
        if (IS_ERR(cred))
                return PTR_ERR(cred);
        state = nfs4_do_open(dir, &path, fmode, openflags, NULL, cred);
        put_rpccred(cred);
        if (IS_ERR(state)) {
                switch (PTR_ERR(state)) {
                        case -EPERM:
                        case -EACCES:
                        case -EDQUOT:
                        case -ENOSPC:
                        case -EROFS:
                                lookup_instantiate_filp(nd, (struct dentry *)state, NULL);
                                return 1;
                        default:
                                goto out_drop;
                }
        }
        if (state->inode == dentry->d_inode) {
                nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
                nfs4_intent_set_file(nd, &path, state, fmode);
                return 1;
        }
        nfs4_close_sync(&path, state, fmode);
out_drop:
        d_drop(dentry);
        return 0;
}

void nfs4_close_context(struct nfs_open_context *ctx, int is_sync)
{
        if (ctx->state == NULL)
                return;
        if (is_sync)
                nfs4_close_sync(&ctx->path, ctx->state, ctx->mode);
        else
                nfs4_close_state(&ctx->path, ctx->state, ctx->mode);
}

static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle)
{
        struct nfs4_server_caps_arg args = {
                .fhandle = fhandle,
        };
        struct nfs4_server_caps_res res = {};
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SERVER_CAPS],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        int status;

        status = nfs4_call_sync(server, &msg, &args, &res, 0);
        if (status == 0) {
                memcpy(server->attr_bitmask, res.attr_bitmask, sizeof(server->attr_bitmask));
                if (res.attr_bitmask[0] & FATTR4_WORD0_ACL)
                        server->caps |= NFS_CAP_ACLS;
                if (res.has_links != 0)
                        server->caps |= NFS_CAP_HARDLINKS;
                if (res.has_symlinks != 0)
                        server->caps |= NFS_CAP_SYMLINKS;
                memcpy(server->cache_consistency_bitmask, res.attr_bitmask, sizeof(server->cache_consistency_bitmask));
                server->cache_consistency_bitmask[0] &= FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE;
                server->cache_consistency_bitmask[1] &= FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY;
                server->acl_bitmask = res.acl_bitmask;
        }

        return status;
}

int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(server,
                                _nfs4_server_capabilities(server, fhandle),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_lookup_root(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_fsinfo *info)
{
        struct nfs4_lookup_root_arg args = {
                .bitmask = nfs4_fattr_bitmap,
        };
        struct nfs4_lookup_res res = {
                .server = server,
                .fattr = info->fattr,
                .fh = fhandle,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOOKUP_ROOT],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        nfs_fattr_init(info->fattr);
        return nfs4_call_sync(server, &msg, &args, &res, 0);
}

static int nfs4_lookup_root(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_fsinfo *info)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(server,
                                _nfs4_lookup_root(server, fhandle, info),
                                &exception);
        } while (exception.retry);
        return err;
}

/*
 * get the file handle for the "/" directory on the server
 */
static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
                              struct nfs_fsinfo *info)
{
        int status;

        status = nfs4_lookup_root(server, fhandle, info);
        if (status == 0)
                status = nfs4_server_capabilities(server, fhandle);
        if (status == 0)
                status = nfs4_do_fsinfo(server, fhandle, info);
        return nfs4_map_errors(status);
}

/*
 * Get locations and (maybe) other attributes of a referral.
 * Note that we'll actually follow the referral later when
 * we detect fsid mismatch in inode revalidation
 */
static int nfs4_get_referral(struct inode *dir, const struct qstr *name, struct nfs_fattr *fattr, struct nfs_fh *fhandle)
{
        int status = -ENOMEM;
        struct page *page = NULL;
        struct nfs4_fs_locations *locations = NULL;

        page = alloc_page(GFP_KERNEL);
        if (page == NULL)
                goto out;
        locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
        if (locations == NULL)
                goto out;

        status = nfs4_proc_fs_locations(dir, name, locations, page);
        if (status != 0)
                goto out;
        /* Make sure server returned a different fsid for the referral */
        if (nfs_fsid_equal(&NFS_SERVER(dir)->fsid, &locations->fattr.fsid)) {
                dprintk("%s: server did not return a different fsid for a referral at %s\n", __func__, name->name);
                status = -EIO;
                goto out;
        }

        memcpy(fattr, &locations->fattr, sizeof(struct nfs_fattr));
        fattr->valid |= NFS_ATTR_FATTR_V4_REFERRAL;
        if (!fattr->mode)
                fattr->mode = S_IFDIR;
        memset(fhandle, 0, sizeof(struct nfs_fh));
out:
        if (page)
                __free_page(page);
        if (locations)
                kfree(locations);
        return status;
}

static int _nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
        struct nfs4_getattr_arg args = {
                .fh = fhandle,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_getattr_res res = {
                .fattr = fattr,
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETATTR],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        
        nfs_fattr_init(fattr);
        return nfs4_call_sync(server, &msg, &args, &res, 0);
}

static int nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(server,
                                _nfs4_proc_getattr(server, fhandle, fattr),
                                &exception);
        } while (exception.retry);
        return err;
}

/* 
 * The file is not closed if it is opened due to the a request to change
 * the size of the file. The open call will not be needed once the
 * VFS layer lookup-intents are implemented.
 *
 * Close is called when the inode is destroyed.
 * If we haven't opened the file for O_WRONLY, we
 * need to in the size_change case to obtain a stateid.
 *
 * Got race?
 * Because OPEN is always done by name in nfsv4, it is
 * possible that we opened a different file by the same
 * name.  We can recognize this race condition, but we
 * can't do anything about it besides returning an error.
 *
 * This will be fixed with VFS changes (lookup-intent).
 */
static int
nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
                  struct iattr *sattr)
{
        struct inode *inode = dentry->d_inode;
        struct rpc_cred *cred = NULL;
        struct nfs4_state *state = NULL;
        int status;

        nfs_fattr_init(fattr);
        
        /* Search for an existing open(O_WRITE) file */
        if (sattr->ia_valid & ATTR_FILE) {
                struct nfs_open_context *ctx;

                ctx = nfs_file_open_context(sattr->ia_file);
                if (ctx) {
                        cred = ctx->cred;
                        state = ctx->state;
                }
        }

        status = nfs4_do_setattr(inode, cred, fattr, sattr, state);
        if (status == 0)
                nfs_setattr_update_inode(inode, sattr);
        return status;
}

static int _nfs4_proc_lookupfh(struct nfs_server *server, const struct nfs_fh *dirfh,
                const struct qstr *name, struct nfs_fh *fhandle,
                struct nfs_fattr *fattr)
{
        int                    status;
        struct nfs4_lookup_arg args = {
                .bitmask = server->attr_bitmask,
                .dir_fh = dirfh,
                .name = name,
        };
        struct nfs4_lookup_res res = {
                .server = server,
                .fattr = fattr,
                .fh = fhandle,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOOKUP],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        nfs_fattr_init(fattr);

        dprintk("NFS call  lookupfh %s\n", name->name);
        status = nfs4_call_sync(server, &msg, &args, &res, 0);
        dprintk("NFS reply lookupfh: %d\n", status);
        return status;
}

static int nfs4_proc_lookupfh(struct nfs_server *server, struct nfs_fh *dirfh,
                              struct qstr *name, struct nfs_fh *fhandle,
                              struct nfs_fattr *fattr)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_lookupfh(server, dirfh, name, fhandle, fattr);
                /* FIXME: !!!! */
                if (err == -NFS4ERR_MOVED) {
                        err = -EREMOTE;
                        break;
                }
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_lookup(struct inode *dir, const struct qstr *name,
                struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
        int status;
        
        dprintk("NFS call  lookup %s\n", name->name);
        status = _nfs4_proc_lookupfh(NFS_SERVER(dir), NFS_FH(dir), name, fhandle, fattr);
        if (status == -NFS4ERR_MOVED)
                status = nfs4_get_referral(dir, name, fattr, fhandle);
        dprintk("NFS reply lookup: %d\n", status);
        return status;
}

static int nfs4_proc_lookup(struct inode *dir, struct qstr *name, struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dir),
                                _nfs4_proc_lookup(dir, name, fhandle, fattr),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_fattr fattr;
        struct nfs4_accessargs args = {
                .fh = NFS_FH(inode),
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_accessres res = {
                .server = server,
                .fattr = &fattr,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_ACCESS],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = entry->cred,
        };
        int mode = entry->mask;
        int status;

        /*
         * Determine which access bits we want to ask for...
         */
        if (mode & MAY_READ)
                args.access |= NFS4_ACCESS_READ;
        if (S_ISDIR(inode->i_mode)) {
                if (mode & MAY_WRITE)
                        args.access |= NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE;
                if (mode & MAY_EXEC)
                        args.access |= NFS4_ACCESS_LOOKUP;
        } else {
                if (mode & MAY_WRITE)
                        args.access |= NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND;
                if (mode & MAY_EXEC)
                        args.access |= NFS4_ACCESS_EXECUTE;
        }
        nfs_fattr_init(&fattr);
        status = nfs4_call_sync(server, &msg, &args, &res, 0);
        if (!status) {
                entry->mask = 0;
                if (res.access & NFS4_ACCESS_READ)
                        entry->mask |= MAY_READ;
                if (res.access & (NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE))
                        entry->mask |= MAY_WRITE;
                if (res.access & (NFS4_ACCESS_LOOKUP|NFS4_ACCESS_EXECUTE))
                        entry->mask |= MAY_EXEC;
                nfs_refresh_inode(inode, &fattr);
        }
        return status;
}

static int nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(inode),
                                _nfs4_proc_access(inode, entry),
                                &exception);
        } while (exception.retry);
        return err;
}

/*
 * TODO: For the time being, we don't try to get any attributes
 * along with any of the zero-copy operations READ, READDIR,
 * READLINK, WRITE.
 *
 * In the case of the first three, we want to put the GETATTR
 * after the read-type operation -- this is because it is hard
 * to predict the length of a GETATTR response in v4, and thus
 * align the READ data correctly.  This means that the GETATTR
 * may end up partially falling into the page cache, and we should
 * shift it into the 'tail' of the xdr_buf before processing.
 * To do this efficiently, we need to know the total length
 * of data received, which doesn't seem to be available outside
 * of the RPC layer.
 *
 * In the case of WRITE, we also want to put the GETATTR after
 * the operation -- in this case because we want to make sure
 * we get the post-operation mtime and size.  This means that
 * we can't use xdr_encode_pages() as written: we need a variant
 * of it which would leave room in the 'tail' iovec.
 *
 * Both of these changes to the XDR layer would in fact be quite
 * minor, but I decided to leave them for a subsequent patch.
 */
static int _nfs4_proc_readlink(struct inode *inode, struct page *page,
                unsigned int pgbase, unsigned int pglen)
{
        struct nfs4_readlink args = {
                .fh       = NFS_FH(inode),
                .pgbase   = pgbase,
                .pglen    = pglen,
                .pages    = &page,
        };
        struct nfs4_readlink_res res;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READLINK],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        return nfs4_call_sync(NFS_SERVER(inode), &msg, &args, &res, 0);
}

static int nfs4_proc_readlink(struct inode *inode, struct page *page,
                unsigned int pgbase, unsigned int pglen)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(inode),
                                _nfs4_proc_readlink(inode, page, pgbase, pglen),
                                &exception);
        } while (exception.retry);
        return err;
}

/*
 * Got race?
 * We will need to arrange for the VFS layer to provide an atomic open.
 * Until then, this create/open method is prone to inefficiency and race
 * conditions due to the lookup, create, and open VFS calls from sys_open()
 * placed on the wire.
 *
 * Given the above sorry state of affairs, I'm simply sending an OPEN.
 * The file will be opened again in the subsequent VFS open call
 * (nfs4_proc_file_open).
 *
 * The open for read will just hang around to be used by any process that
 * opens the file O_RDONLY. This will all be resolved with the VFS changes.
 */

static int
nfs4_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
                 int flags, struct nameidata *nd)
{
        struct path path = {
                .mnt = nd->path.mnt,
                .dentry = dentry,
        };
        struct nfs4_state *state;
        struct rpc_cred *cred;
        fmode_t fmode = flags & (FMODE_READ | FMODE_WRITE);
        int status = 0;

        cred = rpc_lookup_cred();
        if (IS_ERR(cred)) {
                status = PTR_ERR(cred);
                goto out;
        }
        state = nfs4_do_open(dir, &path, fmode, flags, sattr, cred);
        d_drop(dentry);
        if (IS_ERR(state)) {
                status = PTR_ERR(state);
                goto out_putcred;
        }
        d_add(dentry, igrab(state->inode));
        nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
        if (flags & O_EXCL) {
                struct nfs_fattr fattr;
                status = nfs4_do_setattr(state->inode, cred, &fattr, sattr, state);
                if (status == 0)
                        nfs_setattr_update_inode(state->inode, sattr);
                nfs_post_op_update_inode(state->inode, &fattr);
        }
        if (status == 0 && (nd->flags & LOOKUP_OPEN) != 0)
                status = nfs4_intent_set_file(nd, &path, state, fmode);
        else
                nfs4_close_sync(&path, state, fmode);
out_putcred:
        put_rpccred(cred);
out:
        return status;
}

static int _nfs4_proc_remove(struct inode *dir, struct qstr *name)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_removeargs args = {
                .fh = NFS_FH(dir),
                .name.len = name->len,
                .name.name = name->name,
                .bitmask = server->attr_bitmask,
        };
        struct nfs_removeres res = {
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_REMOVE],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        int                     status;

        nfs_fattr_init(&res.dir_attr);
        status = nfs4_call_sync(server, &msg, &args, &res, 1);
        if (status == 0) {
                update_changeattr(dir, &res.cinfo);
                nfs_post_op_update_inode(dir, &res.dir_attr);
        }
        return status;
}

static int nfs4_proc_remove(struct inode *dir, struct qstr *name)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dir),
                                _nfs4_proc_remove(dir, name),
                                &exception);
        } while (exception.retry);
        return err;
}

static void nfs4_proc_unlink_setup(struct rpc_message *msg, struct inode *dir)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_removeargs *args = msg->rpc_argp;
        struct nfs_removeres *res = msg->rpc_resp;

        args->bitmask = server->cache_consistency_bitmask;
        res->server = server;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_REMOVE];
}

static int nfs4_proc_unlink_done(struct rpc_task *task, struct inode *dir)
{
        struct nfs_removeres *res = task->tk_msg.rpc_resp;

        nfs4_sequence_done(res->server, &res->seq_res, task->tk_status);
        if (nfs4_async_handle_error(task, res->server, NULL) == -EAGAIN)
                return 0;
        nfs4_sequence_free_slot(res->server->nfs_client, &res->seq_res);
        update_changeattr(dir, &res->cinfo);
        nfs_post_op_update_inode(dir, &res->dir_attr);
        return 1;
}

static int _nfs4_proc_rename(struct inode *old_dir, struct qstr *old_name,
                struct inode *new_dir, struct qstr *new_name)
{
        struct nfs_server *server = NFS_SERVER(old_dir);
        struct nfs4_rename_arg arg = {
                .old_dir = NFS_FH(old_dir),
                .new_dir = NFS_FH(new_dir),
                .old_name = old_name,
                .new_name = new_name,
                .bitmask = server->attr_bitmask,
        };
        struct nfs_fattr old_fattr, new_fattr;
        struct nfs4_rename_res res = {
                .server = server,
                .old_fattr = &old_fattr,
                .new_fattr = &new_fattr,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RENAME],
                .rpc_argp = &arg,
                .rpc_resp = &res,
        };
        int                     status;
        
        nfs_fattr_init(res.old_fattr);
        nfs_fattr_init(res.new_fattr);
        status = nfs4_call_sync(server, &msg, &arg, &res, 1);

        if (!status) {
                update_changeattr(old_dir, &res.old_cinfo);
                nfs_post_op_update_inode(old_dir, res.old_fattr);
                update_changeattr(new_dir, &res.new_cinfo);
                nfs_post_op_update_inode(new_dir, res.new_fattr);
        }
        return status;
}

static int nfs4_proc_rename(struct inode *old_dir, struct qstr *old_name,
                struct inode *new_dir, struct qstr *new_name)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(old_dir),
                                _nfs4_proc_rename(old_dir, old_name,
                                        new_dir, new_name),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_link(struct inode *inode, struct inode *dir, struct qstr *name)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_link_arg arg = {
                .fh     = NFS_FH(inode),
                .dir_fh = NFS_FH(dir),
                .name   = name,
                .bitmask = server->attr_bitmask,
        };
        struct nfs_fattr fattr, dir_attr;
        struct nfs4_link_res res = {
                .server = server,
                .fattr = &fattr,
                .dir_attr = &dir_attr,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LINK],
                .rpc_argp = &arg,
                .rpc_resp = &res,
        };
        int                     status;

        nfs_fattr_init(res.fattr);
        nfs_fattr_init(res.dir_attr);
        status = nfs4_call_sync(server, &msg, &arg, &res, 1);
        if (!status) {
                update_changeattr(dir, &res.cinfo);
                nfs_post_op_update_inode(dir, res.dir_attr);
                nfs_post_op_update_inode(inode, res.fattr);
        }

        return status;
}

static int nfs4_proc_link(struct inode *inode, struct inode *dir, struct qstr *name)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(inode),
                                _nfs4_proc_link(inode, dir, name),
                                &exception);
        } while (exception.retry);
        return err;
}

struct nfs4_createdata {
        struct rpc_message msg;
        struct nfs4_create_arg arg;
        struct nfs4_create_res res;
        struct nfs_fh fh;
        struct nfs_fattr fattr;
        struct nfs_fattr dir_fattr;
};

static struct nfs4_createdata *nfs4_alloc_createdata(struct inode *dir,
                struct qstr *name, struct iattr *sattr, u32 ftype)
{
        struct nfs4_createdata *data;

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (data != NULL) {
                struct nfs_server *server = NFS_SERVER(dir);

                data->msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CREATE];
                data->msg.rpc_argp = &data->arg;
                data->msg.rpc_resp = &data->res;
                data->arg.dir_fh = NFS_FH(dir);
                data->arg.server = server;
                data->arg.name = name;
                data->arg.attrs = sattr;
                data->arg.ftype = ftype;
                data->arg.bitmask = server->attr_bitmask;
                data->res.server = server;
                data->res.fh = &data->fh;
                data->res.fattr = &data->fattr;
                data->res.dir_fattr = &data->dir_fattr;
                nfs_fattr_init(data->res.fattr);
                nfs_fattr_init(data->res.dir_fattr);
        }
        return data;
}

static int nfs4_do_create(struct inode *dir, struct dentry *dentry, struct nfs4_createdata *data)
{
        int status = nfs4_call_sync(NFS_SERVER(dir), &data->msg,
                                    &data->arg, &data->res, 1);
        if (status == 0) {
                update_changeattr(dir, &data->res.dir_cinfo);
                nfs_post_op_update_inode(dir, data->res.dir_fattr);
                status = nfs_instantiate(dentry, data->res.fh, data->res.fattr);
        }
        return status;
}

static void nfs4_free_createdata(struct nfs4_createdata *data)
{
        kfree(data);
}

static int _nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
                struct page *page, unsigned int len, struct iattr *sattr)
{
        struct nfs4_createdata *data;
        int status = -ENAMETOOLONG;

        if (len > NFS4_MAXPATHLEN)
                goto out;

        status = -ENOMEM;
        data = nfs4_alloc_createdata(dir, &dentry->d_name, sattr, NF4LNK);
        if (data == NULL)
                goto out;

        data->msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SYMLINK];
        data->arg.u.symlink.pages = &page;
        data->arg.u.symlink.len = len;
        
        status = nfs4_do_create(dir, dentry, data);

        nfs4_free_createdata(data);
out:
        return status;
}

static int nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
                struct page *page, unsigned int len, struct iattr *sattr)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dir),
                                _nfs4_proc_symlink(dir, dentry, page,
                                                        len, sattr),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr)
{
        struct nfs4_createdata *data;
        int status = -ENOMEM;

        data = nfs4_alloc_createdata(dir, &dentry->d_name, sattr, NF4DIR);
        if (data == NULL)
                goto out;

        status = nfs4_do_create(dir, dentry, data);

        nfs4_free_createdata(data);
out:
        return status;
}

static int nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dir),
                                _nfs4_proc_mkdir(dir, dentry, sattr),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
                  u64 cookie, struct page *page, unsigned int count, int plus)
{
        struct inode            *dir = dentry->d_inode;
        struct nfs4_readdir_arg args = {
                .fh = NFS_FH(dir),
                .pages = &page,
                .pgbase = 0,
                .count = count,
                .bitmask = NFS_SERVER(dentry->d_inode)->cache_consistency_bitmask,
        };
        struct nfs4_readdir_res res;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READDIR],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };
        int                     status;

        dprintk("%s: dentry = %s/%s, cookie = %Lu\n", __func__,
                        dentry->d_parent->d_name.name,
                        dentry->d_name.name,
                        (unsigned long long)cookie);
        nfs4_setup_readdir(cookie, NFS_COOKIEVERF(dir), dentry, &args);
        res.pgbase = args.pgbase;
        status = nfs4_call_sync(NFS_SERVER(dir), &msg, &args, &res, 0);
        if (status == 0)
                memcpy(NFS_COOKIEVERF(dir), res.verifier.data, NFS4_VERIFIER_SIZE);

        nfs_invalidate_atime(dir);

        dprintk("%s: returns %d\n", __func__, status);
        return status;
}

static int nfs4_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
                  u64 cookie, struct page *page, unsigned int count, int plus)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dentry->d_inode),
                                _nfs4_proc_readdir(dentry, cred, cookie,
                                        page, count, plus),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_mknod(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr, dev_t rdev)
{
        struct nfs4_createdata *data;
        int mode = sattr->ia_mode;
        int status = -ENOMEM;

        BUG_ON(!(sattr->ia_valid & ATTR_MODE));
        BUG_ON(!S_ISFIFO(mode) && !S_ISBLK(mode) && !S_ISCHR(mode) && !S_ISSOCK(mode));

        data = nfs4_alloc_createdata(dir, &dentry->d_name, sattr, NF4SOCK);
        if (data == NULL)
                goto out;

        if (S_ISFIFO(mode))
                data->arg.ftype = NF4FIFO;
        else if (S_ISBLK(mode)) {
                data->arg.ftype = NF4BLK;
                data->arg.u.device.specdata1 = MAJOR(rdev);
                data->arg.u.device.specdata2 = MINOR(rdev);
        }
        else if (S_ISCHR(mode)) {
                data->arg.ftype = NF4CHR;
                data->arg.u.device.specdata1 = MAJOR(rdev);
                data->arg.u.device.specdata2 = MINOR(rdev);
        }
        
        status = nfs4_do_create(dir, dentry, data);

        nfs4_free_createdata(data);
out:
        return status;
}

static int nfs4_proc_mknod(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr, dev_t rdev)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dir),
                                _nfs4_proc_mknod(dir, dentry, sattr, rdev),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_statfs(struct nfs_server *server, struct nfs_fh *fhandle,
                 struct nfs_fsstat *fsstat)
{
        struct nfs4_statfs_arg args = {
                .fh = fhandle,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_statfs_res res = {
                .fsstat = fsstat,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_STATFS],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        nfs_fattr_init(fsstat->fattr);
        return  nfs4_call_sync(server, &msg, &args, &res, 0);
}

static int nfs4_proc_statfs(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fsstat *fsstat)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(server,
                                _nfs4_proc_statfs(server, fhandle, fsstat),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_do_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_fsinfo *fsinfo)
{
        struct nfs4_fsinfo_arg args = {
                .fh = fhandle,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_fsinfo_res res = {
                .fsinfo = fsinfo,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_FSINFO],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        return nfs4_call_sync(server, &msg, &args, &res, 0);
}

static int nfs4_do_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fsinfo *fsinfo)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = nfs4_handle_exception(server,
                                _nfs4_do_fsinfo(server, fhandle, fsinfo),
                                &exception);
        } while (exception.retry);
        return err;
}

static int nfs4_proc_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fsinfo *fsinfo)
{
        nfs_fattr_init(fsinfo->fattr);
        return nfs4_do_fsinfo(server, fhandle, fsinfo);
}

static int _nfs4_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_pathconf *pathconf)
{
        struct nfs4_pathconf_arg args = {
                .fh = fhandle,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_pathconf_res res = {
                .pathconf = pathconf,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_PATHCONF],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        /* None of the pathconf attributes are mandatory to implement */
        if ((args.bitmask[0] & nfs4_pathconf_bitmap[0]) == 0) {
                memset(pathconf, 0, sizeof(*pathconf));
                return 0;
        }

        nfs_fattr_init(pathconf->fattr);
        return nfs4_call_sync(server, &msg, &args, &res, 0);
}

static int nfs4_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_pathconf *pathconf)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = nfs4_handle_exception(server,
                                _nfs4_proc_pathconf(server, fhandle, pathconf),
                                &exception);
        } while (exception.retry);
        return err;
}

static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
{
        struct nfs_server *server = NFS_SERVER(data->inode);

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

        /* nfs4_sequence_free_slot called in the read rpc_call_done */
        nfs4_sequence_done(server, &data->res.seq_res, task->tk_status);

        if (nfs4_async_handle_error(task, server, data->args.context->state) == -EAGAIN) {
                nfs4_restart_rpc(task, server->nfs_client);
                return -EAGAIN;
        }

        nfs_invalidate_atime(data->inode);
        if (task->tk_status > 0)
                renew_lease(server, data->timestamp);
        return 0;
}

static void nfs4_proc_read_setup(struct nfs_read_data *data, struct rpc_message *msg)
{
        data->timestamp   = jiffies;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ];
}

static int nfs4_write_done(struct rpc_task *task, struct nfs_write_data *data)
{
        struct inode *inode = data->inode;
        
        /* slot is freed in nfs_writeback_done */
        nfs4_sequence_done(NFS_SERVER(inode), &data->res.seq_res,
                           task->tk_status);

        if (nfs4_async_handle_error(task, NFS_SERVER(inode), data->args.context->state) == -EAGAIN) {
                nfs4_restart_rpc(task, NFS_SERVER(inode)->nfs_client);
                return -EAGAIN;
        }
        if (task->tk_status >= 0) {
                renew_lease(NFS_SERVER(inode), data->timestamp);
                nfs_post_op_update_inode_force_wcc(inode, data->res.fattr);
        }
        return 0;
}

static void nfs4_proc_write_setup(struct nfs_write_data *data, struct rpc_message *msg)
{
        struct nfs_server *server = NFS_SERVER(data->inode);

        data->args.bitmask = server->cache_consistency_bitmask;
        data->res.server = server;
        data->timestamp   = jiffies;

        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_WRITE];
}

static int nfs4_commit_done(struct rpc_task *task, struct nfs_write_data *data)
{
        struct inode *inode = data->inode;
        
        nfs4_sequence_done(NFS_SERVER(inode), &data->res.seq_res,
                           task->tk_status);
        if (nfs4_async_handle_error(task, NFS_SERVER(inode), NULL) == -EAGAIN) {
                nfs4_restart_rpc(task, NFS_SERVER(inode)->nfs_client);
                return -EAGAIN;
        }
        nfs4_sequence_free_slot(NFS_SERVER(inode)->nfs_client,
                                &data->res.seq_res);
        nfs_refresh_inode(inode, data->res.fattr);
        return 0;
}

static void nfs4_proc_commit_setup(struct nfs_write_data *data, struct rpc_message *msg)
{
        struct nfs_server *server = NFS_SERVER(data->inode);
        
        data->args.bitmask = server->cache_consistency_bitmask;
        data->res.server = server;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_COMMIT];
}

/*
 * nfs4_proc_async_renew(): This is not one of the nfs_rpc_ops; it is a special
 * standalone procedure for queueing an asynchronous RENEW.
 */
static void nfs4_renew_done(struct rpc_task *task, void *data)
{
        struct nfs_client *clp = (struct nfs_client *)task->tk_msg.rpc_argp;
        unsigned long timestamp = (unsigned long)data;

        if (task->tk_status < 0) {
                /* Unless we're shutting down, schedule state recovery! */
                if (test_bit(NFS_CS_RENEWD, &clp->cl_res_state) != 0)
                        nfs4_schedule_state_recovery(clp);
                return;
        }
        spin_lock(&clp->cl_lock);
        if (time_before(clp->cl_last_renewal,timestamp))
                clp->cl_last_renewal = timestamp;
        spin_unlock(&clp->cl_lock);
}

static const struct rpc_call_ops nfs4_renew_ops = {
        .rpc_call_done = nfs4_renew_done,
};

int nfs4_proc_async_renew(struct nfs_client *clp, struct rpc_cred *cred)
{
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_RENEW],
                .rpc_argp       = clp,
                .rpc_cred       = cred,
        };

        return rpc_call_async(clp->cl_rpcclient, &msg, RPC_TASK_SOFT,
                        &nfs4_renew_ops, (void *)jiffies);
}

int nfs4_proc_renew(struct nfs_client *clp, struct rpc_cred *cred)
{
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_RENEW],
                .rpc_argp       = clp,
                .rpc_cred       = cred,
        };
        unsigned long now = jiffies;
        int status;

        status = rpc_call_sync(clp->cl_rpcclient, &msg, 0);
        if (status < 0)
                return status;
        spin_lock(&clp->cl_lock);
        if (time_before(clp->cl_last_renewal,now))
                clp->cl_last_renewal = now;
        spin_unlock(&clp->cl_lock);
        return 0;
}

static inline int nfs4_server_supports_acls(struct nfs_server *server)
{
        return (server->caps & NFS_CAP_ACLS)
                && (server->acl_bitmask & ACL4_SUPPORT_ALLOW_ACL)
                && (server->acl_bitmask & ACL4_SUPPORT_DENY_ACL);
}

/* Assuming that XATTR_SIZE_MAX is a multiple of PAGE_CACHE_SIZE, and that
 * it's OK to put sizeof(void) * (XATTR_SIZE_MAX/PAGE_CACHE_SIZE) bytes on
 * the stack.
 */
#define NFS4ACL_MAXPAGES (XATTR_SIZE_MAX >> PAGE_CACHE_SHIFT)

static void buf_to_pages(const void *buf, size_t buflen,
                struct page **pages, unsigned int *pgbase)
{
        const void *p = buf;

        *pgbase = offset_in_page(buf);
        p -= *pgbase;
        while (p < buf + buflen) {
                *(pages++) = virt_to_page(p);
                p += PAGE_CACHE_SIZE;
        }
}

struct nfs4_cached_acl {
        int cached;
        size_t len;
        char data[0];
};

static void nfs4_set_cached_acl(struct inode *inode, struct nfs4_cached_acl *acl)
{
        struct nfs_inode *nfsi = NFS_I(inode);

        spin_lock(&inode->i_lock);
        kfree(nfsi->nfs4_acl);
        nfsi->nfs4_acl = acl;
        spin_unlock(&inode->i_lock);
}

static void nfs4_zap_acl_attr(struct inode *inode)
{
        nfs4_set_cached_acl(inode, NULL);
}

static inline ssize_t nfs4_read_cached_acl(struct inode *inode, char *buf, size_t buflen)
{
        struct nfs_inode *nfsi = NFS_I(inode);
        struct nfs4_cached_acl *acl;
        int ret = -ENOENT;

        spin_lock(&inode->i_lock);
        acl = nfsi->nfs4_acl;
        if (acl == NULL)
                goto out;
        if (buf == NULL) /* user is just asking for length */
                goto out_len;
        if (acl->cached == 0)
                goto out;
        ret = -ERANGE; /* see getxattr(2) man page */
        if (acl->len > buflen)
                goto out;
        memcpy(buf, acl->data, acl->len);
out_len:
        ret = acl->len;
out:
        spin_unlock(&inode->i_lock);
        return ret;
}

static void nfs4_write_cached_acl(struct inode *inode, const char *buf, size_t acl_len)
{
        struct nfs4_cached_acl *acl;

        if (buf && acl_len <= PAGE_SIZE) {
                acl = kmalloc(sizeof(*acl) + acl_len, GFP_KERNEL);
                if (acl == NULL)
                        goto out;
                acl->cached = 1;
                memcpy(acl->data, buf, acl_len);
        } else {
                acl = kmalloc(sizeof(*acl), GFP_KERNEL);
                if (acl == NULL)
                        goto out;
                acl->cached = 0;
        }
        acl->len = acl_len;
out:
        nfs4_set_cached_acl(inode, acl);
}

static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t buflen)
{
        struct page *pages[NFS4ACL_MAXPAGES];
        struct nfs_getaclargs args = {
                .fh = NFS_FH(inode),
                .acl_pages = pages,
                .acl_len = buflen,
        };
        struct nfs_getaclres res = {
                .acl_len = buflen,
        };
        void *resp_buf;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETACL],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        struct page *localpage = NULL;
        int ret;

        if (buflen < PAGE_SIZE) {
                /* As long as we're doing a round trip to the server anyway,
                 * let's be prepared for a page of acl data. */
                localpage = alloc_page(GFP_KERNEL);
                resp_buf = page_address(localpage);
                if (localpage == NULL)
                        return -ENOMEM;
                args.acl_pages[0] = localpage;
                args.acl_pgbase = 0;
                args.acl_len = PAGE_SIZE;
        } else {
                resp_buf = buf;
                buf_to_pages(buf, buflen, args.acl_pages, &args.acl_pgbase);
        }
        ret = nfs4_call_sync(NFS_SERVER(inode), &msg, &args, &res, 0);
        if (ret)
                goto out_free;
        if (res.acl_len > args.acl_len)
                nfs4_write_cached_acl(inode, NULL, res.acl_len);
        else
                nfs4_write_cached_acl(inode, resp_buf, res.acl_len);
        if (buf) {
                ret = -ERANGE;
                if (res.acl_len > buflen)
                        goto out_free;
                if (localpage)
                        memcpy(buf, resp_buf, res.acl_len);
        }
        ret = res.acl_len;
out_free:
        if (localpage)
                __free_page(localpage);
        return ret;
}

static ssize_t nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t buflen)
{
        struct nfs4_exception exception = { };
        ssize_t ret;
        do {
                ret = __nfs4_get_acl_uncached(inode, buf, buflen);
                if (ret >= 0)
                        break;
                ret = nfs4_handle_exception(NFS_SERVER(inode), ret, &exception);
        } while (exception.retry);
        return ret;
}

static ssize_t nfs4_proc_get_acl(struct inode *inode, void *buf, size_t buflen)
{
        struct nfs_server *server = NFS_SERVER(inode);
        int ret;

        if (!nfs4_server_supports_acls(server))
                return -EOPNOTSUPP;
        ret = nfs_revalidate_inode(server, inode);
        if (ret < 0)
                return ret;
        if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_ACL)
                nfs_zap_acl_cache(inode);
        ret = nfs4_read_cached_acl(inode, buf, buflen);
        if (ret != -ENOENT)
                return ret;
        return nfs4_get_acl_uncached(inode, buf, buflen);
}

static int __nfs4_proc_set_acl(struct inode *inode, const void *buf, size_t buflen)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct page *pages[NFS4ACL_MAXPAGES];
        struct nfs_setaclargs arg = {
                .fh             = NFS_FH(inode),
                .acl_pages      = pages,
                .acl_len        = buflen,
        };
        struct nfs_setaclres res;
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_SETACL],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
        };
        int ret;

        if (!nfs4_server_supports_acls(server))
                return -EOPNOTSUPP;
        nfs_inode_return_delegation(inode);
        buf_to_pages(buf, buflen, arg.acl_pages, &arg.acl_pgbase);
        ret = nfs4_call_sync(server, &msg, &arg, &res, 1);
        nfs_access_zap_cache(inode);
        nfs_zap_acl_cache(inode);
        return ret;
}

static int nfs4_proc_set_acl(struct inode *inode, const void *buf, size_t buflen)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(inode),
                                __nfs4_proc_set_acl(inode, buf, buflen),
                                &exception);
        } while (exception.retry);
        return err;
}

static int
_nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server, struct nfs_client *clp, struct nfs4_state *state)
{
        if (!clp || task->tk_status >= 0)
                return 0;
        switch(task->tk_status) {
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_OPENMODE:
                        if (state == NULL)
                                break;
                        nfs4_state_mark_reclaim_nograce(clp, state);
                case -NFS4ERR_STALE_CLIENTID:
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_EXPIRED:
                        rpc_sleep_on(&clp->cl_rpcwaitq, task, NULL);
                        nfs4_schedule_state_recovery(clp);
                        if (test_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) == 0)
                                rpc_wake_up_queued_task(&clp->cl_rpcwaitq, task);
                        task->tk_status = 0;
                        return -EAGAIN;
#if defined(CONFIG_NFS_V4_1)
                case -NFS4ERR_BADSESSION:
                case -NFS4ERR_BADSLOT:
                case -NFS4ERR_BAD_HIGH_SLOT:
                case -NFS4ERR_DEADSESSION:
                case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
                case -NFS4ERR_SEQ_FALSE_RETRY:
                case -NFS4ERR_SEQ_MISORDERED:
                        dprintk("%s ERROR %d, Reset session\n", __func__,
                                task->tk_status);
                        set_bit(NFS4CLNT_SESSION_SETUP, &clp->cl_state);
                        task->tk_status = 0;
                        return -EAGAIN;
#endif /* CONFIG_NFS_V4_1 */
                case -NFS4ERR_DELAY:
                        if (server)
                                nfs_inc_server_stats(server, NFSIOS_DELAY);
                case -NFS4ERR_GRACE:
                        rpc_delay(task, NFS4_POLL_RETRY_MAX);
                        task->tk_status = 0;
                        return -EAGAIN;
                case -NFS4ERR_OLD_STATEID:
                        task->tk_status = 0;
                        return -EAGAIN;
        }
        task->tk_status = nfs4_map_errors(task->tk_status);
        return 0;
}

static int
nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server, struct nfs4_state *state)
{
        return _nfs4_async_handle_error(task, server, server->nfs_client, state);
}

int nfs4_proc_setclientid(struct nfs_client *clp, u32 program, unsigned short port, struct rpc_cred *cred)
{
        nfs4_verifier sc_verifier;
        struct nfs4_setclientid setclientid = {
                .sc_verifier = &sc_verifier,
                .sc_prog = program,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SETCLIENTID],
                .rpc_argp = &setclientid,
                .rpc_resp = clp,
                .rpc_cred = cred,
        };
        __be32 *p;
        int loop = 0;
        int status;

        p = (__be32*)sc_verifier.data;
        *p++ = htonl((u32)clp->cl_boot_time.tv_sec);
        *p = htonl((u32)clp->cl_boot_time.tv_nsec);

        for(;;) {
                setclientid.sc_name_len = scnprintf(setclientid.sc_name,
                                sizeof(setclientid.sc_name), "%s/%s %s %s %u",
                                clp->cl_ipaddr,
                                rpc_peeraddr2str(clp->cl_rpcclient,
                                                        RPC_DISPLAY_ADDR),
                                rpc_peeraddr2str(clp->cl_rpcclient,
                                                        RPC_DISPLAY_PROTO),
                                clp->cl_rpcclient->cl_auth->au_ops->au_name,
                                clp->cl_id_uniquifier);
                setclientid.sc_netid_len = scnprintf(setclientid.sc_netid,
                                sizeof(setclientid.sc_netid),
                                rpc_peeraddr2str(clp->cl_rpcclient,
                                                        RPC_DISPLAY_NETID));
                setclientid.sc_uaddr_len = scnprintf(setclientid.sc_uaddr,
                                sizeof(setclientid.sc_uaddr), "%s.%u.%u",
                                clp->cl_ipaddr, port >> 8, port & 255);

                status = rpc_call_sync(clp->cl_rpcclient, &msg, 0);
                if (status != -NFS4ERR_CLID_INUSE)
                        break;
                if (signalled())
                        break;
                if (loop++ & 1)
                        ssleep(clp->cl_lease_time + 1);
                else
                        if (++clp->cl_id_uniquifier == 0)
                                break;
        }
        return status;
}

static int _nfs4_proc_setclientid_confirm(struct nfs_client *clp, struct rpc_cred *cred)
{
        struct nfs_fsinfo fsinfo;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SETCLIENTID_CONFIRM],
                .rpc_argp = clp,
                .rpc_resp = &fsinfo,
                .rpc_cred = cred,
        };
        unsigned long now;
        int status;

        now = jiffies;
        status = rpc_call_sync(clp->cl_rpcclient, &msg, 0);
        if (status == 0) {
                spin_lock(&clp->cl_lock);
                clp->cl_lease_time = fsinfo.lease_time * HZ;
                clp->cl_last_renewal = now;
                spin_unlock(&clp->cl_lock);
        }
        return status;
}

int nfs4_proc_setclientid_confirm(struct nfs_client *clp, struct rpc_cred *cred)
{
        long timeout = 0;
        int err;
        do {
                err = _nfs4_proc_setclientid_confirm(clp, cred);
                switch (err) {
                        case 0:
                                return err;
                        case -NFS4ERR_RESOURCE:
                                /* The IBM lawyers misread another document! */
                        case -NFS4ERR_DELAY:
                                err = nfs4_delay(clp->cl_rpcclient, &timeout);
                }
        } while (err == 0);
        return err;
}

struct nfs4_delegreturndata {
        struct nfs4_delegreturnargs args;
        struct nfs4_delegreturnres res;
        struct nfs_fh fh;
        nfs4_stateid stateid;
        unsigned long timestamp;
        struct nfs_fattr fattr;
        int rpc_status;
};

static void nfs4_delegreturn_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_delegreturndata *data = calldata;

        nfs4_sequence_done_free_slot(data->res.server, &data->res.seq_res,
                                     task->tk_status);

        data->rpc_status = task->tk_status;
        if (data->rpc_status == 0)
                renew_lease(data->res.server, data->timestamp);
}

static void nfs4_delegreturn_release(void *calldata)
{
        kfree(calldata);
}

#if defined(CONFIG_NFS_V4_1)
static void nfs4_delegreturn_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_delegreturndata *d_data;

        d_data = (struct nfs4_delegreturndata *)data;

        if (nfs4_setup_sequence(d_data->res.server->nfs_client,
                                &d_data->args.seq_args,
                                &d_data->res.seq_res, 1, task))
                return;
        rpc_call_start(task);
}
#endif /* CONFIG_NFS_V4_1 */

static const struct rpc_call_ops nfs4_delegreturn_ops = {
#if defined(CONFIG_NFS_V4_1)
        .rpc_call_prepare = nfs4_delegreturn_prepare,
#endif /* CONFIG_NFS_V4_1 */
        .rpc_call_done = nfs4_delegreturn_done,
        .rpc_release = nfs4_delegreturn_release,
};

static int _nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid, int issync)
{
        struct nfs4_delegreturndata *data;
        struct nfs_server *server = NFS_SERVER(inode);
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DELEGRETURN],
                .rpc_cred = cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_delegreturn_ops,
                .flags = RPC_TASK_ASYNC,
        };
        int status = 0;

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (data == NULL)
                return -ENOMEM;
        data->args.fhandle = &data->fh;
        data->args.stateid = &data->stateid;
        data->args.bitmask = server->attr_bitmask;
        nfs_copy_fh(&data->fh, NFS_FH(inode));
        memcpy(&data->stateid, stateid, sizeof(data->stateid));
        data->res.fattr = &data->fattr;
        data->res.server = server;
        data->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        nfs_fattr_init(data->res.fattr);
        data->timestamp = jiffies;
        data->rpc_status = 0;

        task_setup_data.callback_data = data;
        msg.rpc_argp = &data->args,
        msg.rpc_resp = &data->res,
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        if (!issync)
                goto out;
        status = nfs4_wait_for_completion_rpc_task(task);
        if (status != 0)
                goto out;
        status = data->rpc_status;
        if (status != 0)
                goto out;
        nfs_refresh_inode(inode, &data->fattr);
out:
        rpc_put_task(task);
        return status;
}

int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid, int issync)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_delegreturn(inode, cred, stateid, issync);
                switch (err) {
                        case -NFS4ERR_STALE_STATEID:
                        case -NFS4ERR_EXPIRED:
                        case 0:
                                return 0;
                }
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

#define NFS4_LOCK_MINTIMEOUT (1 * HZ)
#define NFS4_LOCK_MAXTIMEOUT (30 * HZ)

/* 
 * sleep, with exponential backoff, and retry the LOCK operation. 
 */
static unsigned long
nfs4_set_lock_task_retry(unsigned long timeout)
{
        schedule_timeout_killable(timeout);
        timeout <<= 1;
        if (timeout > NFS4_LOCK_MAXTIMEOUT)
                return NFS4_LOCK_MAXTIMEOUT;
        return timeout;
}

static int _nfs4_proc_getlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct inode *inode = state->inode;
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_client *clp = server->nfs_client;
        struct nfs_lockt_args arg = {
                .fh = NFS_FH(inode),
                .fl = request,
        };
        struct nfs_lockt_res res = {
                .denied = request,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_LOCKT],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
                .rpc_cred       = state->owner->so_cred,
        };
        struct nfs4_lock_state *lsp;
        int status;

        arg.lock_owner.clientid = clp->cl_clientid;
        status = nfs4_set_lock_state(state, request);
        if (status != 0)
                goto out;
        lsp = request->fl_u.nfs4_fl.owner;
        arg.lock_owner.id = lsp->ls_id.id;
        status = nfs4_call_sync(server, &msg, &arg, &res, 1);
        switch (status) {
                case 0:
                        request->fl_type = F_UNLCK;
                        break;
                case -NFS4ERR_DENIED:
                        status = 0;
        }
        request->fl_ops->fl_release_private(request);
out:
        return status;
}

static int nfs4_proc_getlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = nfs4_handle_exception(NFS_SERVER(state->inode),
                                _nfs4_proc_getlk(state, cmd, request),
                                &exception);
        } while (exception.retry);
        return err;
}

static int do_vfs_lock(struct file *file, struct file_lock *fl)
{
        int res = 0;
        switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
                case FL_POSIX:
                        res = posix_lock_file_wait(file, fl);
                        break;
                case FL_FLOCK:
                        res = flock_lock_file_wait(file, fl);
                        break;
                default:
                        BUG();
        }
        return res;
}

struct nfs4_unlockdata {
        struct nfs_locku_args arg;
        struct nfs_locku_res res;
        struct nfs4_lock_state *lsp;
        struct nfs_open_context *ctx;
        struct file_lock fl;
        const struct nfs_server *server;
        unsigned long timestamp;
};

static struct nfs4_unlockdata *nfs4_alloc_unlockdata(struct file_lock *fl,
                struct nfs_open_context *ctx,
                struct nfs4_lock_state *lsp,
                struct nfs_seqid *seqid)
{
        struct nfs4_unlockdata *p;
        struct inode *inode = lsp->ls_state->inode;

        p = kzalloc(sizeof(*p), GFP_KERNEL);
        if (p == NULL)
                return NULL;
        p->arg.fh = NFS_FH(inode);
        p->arg.fl = &p->fl;
        p->arg.seqid = seqid;
        p->res.seqid = seqid;
        p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        p->arg.stateid = &lsp->ls_stateid;
        p->lsp = lsp;
        atomic_inc(&lsp->ls_count);
        /* Ensure we don't close file until we're done freeing locks! */
        p->ctx = get_nfs_open_context(ctx);
        memcpy(&p->fl, fl, sizeof(p->fl));
        p->server = NFS_SERVER(inode);
        return p;
}

static void nfs4_locku_release_calldata(void *data)
{
        struct nfs4_unlockdata *calldata = data;
        nfs_free_seqid(calldata->arg.seqid);
        nfs4_put_lock_state(calldata->lsp);
        put_nfs_open_context(calldata->ctx);
        kfree(calldata);
}

static void nfs4_locku_done(struct rpc_task *task, void *data)
{
        struct nfs4_unlockdata *calldata = data;

        nfs4_sequence_done(calldata->server, &calldata->res.seq_res,
                           task->tk_status);
        if (RPC_ASSASSINATED(task))
                return;
        switch (task->tk_status) {
                case 0:
                        memcpy(calldata->lsp->ls_stateid.data,
                                        calldata->res.stateid.data,
                                        sizeof(calldata->lsp->ls_stateid.data));
                        renew_lease(calldata->server, calldata->timestamp);
                        break;
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_OLD_STATEID:
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_EXPIRED:
                        break;
                default:
                        if (nfs4_async_handle_error(task, calldata->server, NULL) == -EAGAIN)
                                nfs4_restart_rpc(task,
                                                calldata->server->nfs_client);
        }
        nfs4_sequence_free_slot(calldata->server->nfs_client,
                                &calldata->res.seq_res);
}

static void nfs4_locku_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_unlockdata *calldata = data;

        if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)
                return;
        if ((calldata->lsp->ls_flags & NFS_LOCK_INITIALIZED) == 0) {
                /* Note: exit _without_ running nfs4_locku_done */
                task->tk_action = NULL;
                return;
        }
        calldata->timestamp = jiffies;
        if (nfs4_setup_sequence(calldata->server->nfs_client,
                                &calldata->arg.seq_args,
                                &calldata->res.seq_res, 1, task))
                return;
        rpc_call_start(task);
}

static const struct rpc_call_ops nfs4_locku_ops = {
        .rpc_call_prepare = nfs4_locku_prepare,
        .rpc_call_done = nfs4_locku_done,
        .rpc_release = nfs4_locku_release_calldata,
};

static struct rpc_task *nfs4_do_unlck(struct file_lock *fl,
                struct nfs_open_context *ctx,
                struct nfs4_lock_state *lsp,
                struct nfs_seqid *seqid)
{
        struct nfs4_unlockdata *data;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOCKU],
                .rpc_cred = ctx->cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = NFS_CLIENT(lsp->ls_state->inode),
                .rpc_message = &msg,
                .callback_ops = &nfs4_locku_ops,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };

        /* Ensure this is an unlock - when canceling a lock, the
         * canceled lock is passed in, and it won't be an unlock.
         */
        fl->fl_type = F_UNLCK;

        data = nfs4_alloc_unlockdata(fl, ctx, lsp, seqid);
        if (data == NULL) {
                nfs_free_seqid(seqid);
                return ERR_PTR(-ENOMEM);
        }

        msg.rpc_argp = &data->arg,
        msg.rpc_resp = &data->res,
        task_setup_data.callback_data = data;
        return rpc_run_task(&task_setup_data);
}

static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs_inode *nfsi = NFS_I(state->inode);
        struct nfs_seqid *seqid;
        struct nfs4_lock_state *lsp;
        struct rpc_task *task;
        int status = 0;
        unsigned char fl_flags = request->fl_flags;

        status = nfs4_set_lock_state(state, request);
        /* Unlock _before_ we do the RPC call */
        request->fl_flags |= FL_EXISTS;
        down_read(&nfsi->rwsem);
        if (do_vfs_lock(request->fl_file, request) == -ENOENT) {
                up_read(&nfsi->rwsem);
                goto out;
        }
        up_read(&nfsi->rwsem);
        if (status != 0)
                goto out;
        /* Is this a delegated lock? */
        if (test_bit(NFS_DELEGATED_STATE, &state->flags))
                goto out;
        lsp = request->fl_u.nfs4_fl.owner;
        seqid = nfs_alloc_seqid(&lsp->ls_seqid);
        status = -ENOMEM;
        if (seqid == NULL)
                goto out;
        task = nfs4_do_unlck(request, nfs_file_open_context(request->fl_file), lsp, seqid);
        status = PTR_ERR(task);
        if (IS_ERR(task))
                goto out;
        status = nfs4_wait_for_completion_rpc_task(task);
        rpc_put_task(task);
out:
        request->fl_flags = fl_flags;
        return status;
}

struct nfs4_lockdata {
        struct nfs_lock_args arg;
        struct nfs_lock_res res;
        struct nfs4_lock_state *lsp;
        struct nfs_open_context *ctx;
        struct file_lock fl;
        unsigned long timestamp;
        int rpc_status;
        int cancelled;
        struct nfs_server *server;
};

static struct nfs4_lockdata *nfs4_alloc_lockdata(struct file_lock *fl,
                struct nfs_open_context *ctx, struct nfs4_lock_state *lsp)
{
        struct nfs4_lockdata *p;
        struct inode *inode = lsp->ls_state->inode;
        struct nfs_server *server = NFS_SERVER(inode);

        p = kzalloc(sizeof(*p), GFP_KERNEL);
        if (p == NULL)
                return NULL;

        p->arg.fh = NFS_FH(inode);
        p->arg.fl = &p->fl;
        p->arg.open_seqid = nfs_alloc_seqid(&lsp->ls_state->owner->so_seqid);
        if (p->arg.open_seqid == NULL)
                goto out_free;
        p->arg.lock_seqid = nfs_alloc_seqid(&lsp->ls_seqid);
        if (p->arg.lock_seqid == NULL)
                goto out_free_seqid;
        p->arg.lock_stateid = &lsp->ls_stateid;
        p->arg.lock_owner.clientid = server->nfs_client->cl_clientid;
        p->arg.lock_owner.id = lsp->ls_id.id;
        p->res.lock_seqid = p->arg.lock_seqid;
        p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        p->lsp = lsp;
        p->server = server;
        atomic_inc(&lsp->ls_count);
        p->ctx = get_nfs_open_context(ctx);
        memcpy(&p->fl, fl, sizeof(p->fl));
        return p;
out_free_seqid:
        nfs_free_seqid(p->arg.open_seqid);
out_free:
        kfree(p);
        return NULL;
}

static void nfs4_lock_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_lockdata *data = calldata;
        struct nfs4_state *state = data->lsp->ls_state;

        dprintk("%s: begin!\n", __func__);
        if (nfs_wait_on_sequence(data->arg.lock_seqid, task) != 0)
                return;
        /* Do we need to do an open_to_lock_owner? */
        if (!(data->arg.lock_seqid->sequence->flags & NFS_SEQID_CONFIRMED)) {
                if (nfs_wait_on_sequence(data->arg.open_seqid, task) != 0)
                        return;
                data->arg.open_stateid = &state->stateid;
                data->arg.new_lock_owner = 1;
                data->res.open_seqid = data->arg.open_seqid;
        } else
                data->arg.new_lock_owner = 0;
        data->timestamp = jiffies;
        if (nfs4_setup_sequence(data->server->nfs_client, &data->arg.seq_args,
                                &data->res.seq_res, 1, task))
                return;
        rpc_call_start(task);
        dprintk("%s: done!, ret = %d\n", __func__, data->rpc_status);
}

static void nfs4_lock_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_lockdata *data = calldata;

        dprintk("%s: begin!\n", __func__);

        nfs4_sequence_done_free_slot(data->server, &data->res.seq_res,
                                     task->tk_status);

        data->rpc_status = task->tk_status;
        if (RPC_ASSASSINATED(task))
                goto out;
        if (data->arg.new_lock_owner != 0) {
                if (data->rpc_status == 0)
                        nfs_confirm_seqid(&data->lsp->ls_seqid, 0);
                else
                        goto out;
        }
        if (data->rpc_status == 0) {
                memcpy(data->lsp->ls_stateid.data, data->res.stateid.data,
                                        sizeof(data->lsp->ls_stateid.data));
                data->lsp->ls_flags |= NFS_LOCK_INITIALIZED;
                renew_lease(NFS_SERVER(data->ctx->path.dentry->d_inode), data->timestamp);
        }
out:
        dprintk("%s: done, ret = %d!\n", __func__, data->rpc_status);
}

static void nfs4_lock_release(void *calldata)
{
        struct nfs4_lockdata *data = calldata;

        dprintk("%s: begin!\n", __func__);
        nfs_free_seqid(data->arg.open_seqid);
        if (data->cancelled != 0) {
                struct rpc_task *task;
                task = nfs4_do_unlck(&data->fl, data->ctx, data->lsp,
                                data->arg.lock_seqid);
                if (!IS_ERR(task))
                        rpc_put_task(task);
                dprintk("%s: cancelling lock!\n", __func__);
        } else
                nfs_free_seqid(data->arg.lock_seqid);
        nfs4_put_lock_state(data->lsp);
        put_nfs_open_context(data->ctx);
        kfree(data);
        dprintk("%s: done!\n", __func__);
}

static const struct rpc_call_ops nfs4_lock_ops = {
        .rpc_call_prepare = nfs4_lock_prepare,
        .rpc_call_done = nfs4_lock_done,
        .rpc_release = nfs4_lock_release,
};

static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *fl, int reclaim)
{
        struct nfs4_lockdata *data;
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOCK],
                .rpc_cred = state->owner->so_cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = NFS_CLIENT(state->inode),
                .rpc_message = &msg,
                .callback_ops = &nfs4_lock_ops,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };
        int ret;

        dprintk("%s: begin!\n", __func__);
        data = nfs4_alloc_lockdata(fl, nfs_file_open_context(fl->fl_file),
                        fl->fl_u.nfs4_fl.owner);
        if (data == NULL)
                return -ENOMEM;
        if (IS_SETLKW(cmd))
                data->arg.block = 1;
        if (reclaim != 0)
                data->arg.reclaim = 1;
        msg.rpc_argp = &data->arg,
        msg.rpc_resp = &data->res,
        task_setup_data.callback_data = data;
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        ret = nfs4_wait_for_completion_rpc_task(task);
        if (ret == 0) {
                ret = data->rpc_status;
                if (ret == -NFS4ERR_DENIED)
                        ret = -EAGAIN;
        } else
                data->cancelled = 1;
        rpc_put_task(task);
        dprintk("%s: done, ret = %d!\n", __func__, ret);
        return ret;
}

static int nfs4_lock_reclaim(struct nfs4_state *state, struct file_lock *request)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = { };
        int err;

        do {
                /* Cache the lock if possible... */
                if (test_bit(NFS_DELEGATED_STATE, &state->flags) != 0)
                        return 0;
                err = _nfs4_do_setlk(state, F_SETLK, request, 1);
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int nfs4_lock_expired(struct nfs4_state *state, struct file_lock *request)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = { };
        int err;

        err = nfs4_set_lock_state(state, request);
        if (err != 0)
                return err;
        do {
                if (test_bit(NFS_DELEGATED_STATE, &state->flags) != 0)
                        return 0;
                err = _nfs4_do_setlk(state, F_SETLK, request, 0);
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs_inode *nfsi = NFS_I(state->inode);
        unsigned char fl_flags = request->fl_flags;
        int status;

        /* Is this a delegated open? */
        status = nfs4_set_lock_state(state, request);
        if (status != 0)
                goto out;
        request->fl_flags |= FL_ACCESS;
        status = do_vfs_lock(request->fl_file, request);
        if (status < 0)
                goto out;
        down_read(&nfsi->rwsem);
        if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
                /* Yes: cache locks! */
                /* ...but avoid races with delegation recall... */
                request->fl_flags = fl_flags & ~FL_SLEEP;
                status = do_vfs_lock(request->fl_file, request);
                goto out_unlock;
        }
        status = _nfs4_do_setlk(state, cmd, request, 0);
        if (status != 0)
                goto out_unlock;
        /* Note: we always want to sleep here! */
        request->fl_flags = fl_flags | FL_SLEEP;
        if (do_vfs_lock(request->fl_file, request) < 0)
                printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
out_unlock:
        up_read(&nfsi->rwsem);
out:
        request->fl_flags = fl_flags;
        return status;
}

static int nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = nfs4_handle_exception(NFS_SERVER(state->inode),
                                _nfs4_proc_setlk(state, cmd, request),
                                &exception);
        } while (exception.retry);
        return err;
}

static int
nfs4_proc_lock(struct file *filp, int cmd, struct file_lock *request)
{
        struct nfs_open_context *ctx;
        struct nfs4_state *state;
        unsigned long timeout = NFS4_LOCK_MINTIMEOUT;
        int status;

        /* verify open state */
        ctx = nfs_file_open_context(filp);
        state = ctx->state;

        if (request->fl_start < 0 || request->fl_end < 0)
                return -EINVAL;

        if (IS_GETLK(cmd))
                return nfs4_proc_getlk(state, F_GETLK, request);

        if (!(IS_SETLK(cmd) || IS_SETLKW(cmd)))
                return -EINVAL;

        if (request->fl_type == F_UNLCK)
                return nfs4_proc_unlck(state, cmd, request);

        do {
                status = nfs4_proc_setlk(state, cmd, request);
                if ((status != -EAGAIN) || IS_SETLK(cmd))
                        break;
                timeout = nfs4_set_lock_task_retry(timeout);
                status = -ERESTARTSYS;
                if (signalled())
                        break;
        } while(status < 0);
        return status;
}

int nfs4_lock_delegation_recall(struct nfs4_state *state, struct file_lock *fl)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = { };
        int err;

        err = nfs4_set_lock_state(state, fl);
        if (err != 0)
                goto out;
        do {
                err = _nfs4_do_setlk(state, F_SETLK, fl, 0);
                if (err != -NFS4ERR_DELAY)
                        break;
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
out:
        return err;
}

#define XATTR_NAME_NFSV4_ACL "system.nfs4_acl"

int nfs4_setxattr(struct dentry *dentry, const char *key, const void *buf,
                size_t buflen, int flags)
{
        struct inode *inode = dentry->d_inode;

        if (strcmp(key, XATTR_NAME_NFSV4_ACL) != 0)
                return -EOPNOTSUPP;

        return nfs4_proc_set_acl(inode, buf, buflen);
}

/* The getxattr man page suggests returning -ENODATA for unknown attributes,
 * and that's what we'll do for e.g. user attributes that haven't been set.
 * But we'll follow ext2/ext3's lead by returning -EOPNOTSUPP for unsupported
 * attributes in kernel-managed attribute namespaces. */
ssize_t nfs4_getxattr(struct dentry *dentry, const char *key, void *buf,
                size_t buflen)
{
        struct inode *inode = dentry->d_inode;

        if (strcmp(key, XATTR_NAME_NFSV4_ACL) != 0)
                return -EOPNOTSUPP;

        return nfs4_proc_get_acl(inode, buf, buflen);
}

ssize_t nfs4_listxattr(struct dentry *dentry, char *buf, size_t buflen)
{
        size_t len = strlen(XATTR_NAME_NFSV4_ACL) + 1;

        if (!nfs4_server_supports_acls(NFS_SERVER(dentry->d_inode)))
                return 0;
        if (buf && buflen < len)
                return -ERANGE;
        if (buf)
                memcpy(buf, XATTR_NAME_NFSV4_ACL, len);
        return len;
}

static void nfs_fixup_referral_attributes(struct nfs_fattr *fattr)
{
        if (!((fattr->valid & NFS_ATTR_FATTR_FILEID) &&
                (fattr->valid & NFS_ATTR_FATTR_FSID) &&
                (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)))
                return;

        fattr->valid |= NFS_ATTR_FATTR_TYPE | NFS_ATTR_FATTR_MODE |
                NFS_ATTR_FATTR_NLINK;
        fattr->mode = S_IFDIR | S_IRUGO | S_IXUGO;
        fattr->nlink = 2;
}

int nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
                struct nfs4_fs_locations *fs_locations, struct page *page)
{
        struct nfs_server *server = NFS_SERVER(dir);
        u32 bitmask[2] = {
                [0] = FATTR4_WORD0_FSID | FATTR4_WORD0_FS_LOCATIONS,
                [1] = FATTR4_WORD1_MOUNTED_ON_FILEID,
        };
        struct nfs4_fs_locations_arg args = {
                .dir_fh = NFS_FH(dir),
                .name = name,
                .page = page,
                .bitmask = bitmask,
        };
        struct nfs4_fs_locations_res res = {
                .fs_locations = fs_locations,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_FS_LOCATIONS],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        int status;

        dprintk("%s: start\n", __func__);
        nfs_fattr_init(&fs_locations->fattr);
        fs_locations->server = server;
        fs_locations->nlocations = 0;
        status = nfs4_call_sync(server, &msg, &args, &res, 0);
        nfs_fixup_referral_attributes(&fs_locations->fattr);
        dprintk("%s: returned status = %d\n", __func__, status);
        return status;
}

#ifdef CONFIG_NFS_V4_1
/*
 * nfs4_proc_exchange_id()
 *
 * Since the clientid has expired, all compounds using sessions
 * associated with the stale clientid will be returning
 * NFS4ERR_BADSESSION in the sequence operation, and will therefore
 * be in some phase of session reset.
 */
static int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
{
        nfs4_verifier verifier;
        struct nfs41_exchange_id_args args = {
                .client = clp,
                .flags = clp->cl_exchange_flags,
        };
        struct nfs41_exchange_id_res res = {
                .client = clp,
        };
        int status;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_EXCHANGE_ID],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };
        __be32 *p;

        dprintk("--> %s\n", __func__);
        BUG_ON(clp == NULL);
        p = (u32 *)verifier.data;
        *p++ = htonl((u32)clp->cl_boot_time.tv_sec);
        *p = htonl((u32)clp->cl_boot_time.tv_nsec);
        args.verifier = &verifier;

        while (1) {
                args.id_len = scnprintf(args.id, sizeof(args.id),
                                        "%s/%s %u",
                                        clp->cl_ipaddr,
                                        rpc_peeraddr2str(clp->cl_rpcclient,
                                                         RPC_DISPLAY_ADDR),
                                        clp->cl_id_uniquifier);

                status = rpc_call_sync(clp->cl_rpcclient, &msg, 0);

                if (status != NFS4ERR_CLID_INUSE)
                        break;

                if (signalled())
                        break;

                if (++clp->cl_id_uniquifier == 0)
                        break;
        }

        dprintk("<-- %s status= %d\n", __func__, status);
        return status;
}

struct nfs4_get_lease_time_data {
        struct nfs4_get_lease_time_args *args;
        struct nfs4_get_lease_time_res *res;
        struct nfs_client *clp;
};

static void nfs4_get_lease_time_prepare(struct rpc_task *task,
                                        void *calldata)
{
        int ret;
        struct nfs4_get_lease_time_data *data =
                        (struct nfs4_get_lease_time_data *)calldata;

        dprintk("--> %s\n", __func__);
        /* just setup sequence, do not trigger session recovery
           since we're invoked within one */
        ret = nfs41_setup_sequence(data->clp->cl_session,
                                        &data->args->la_seq_args,
                                        &data->res->lr_seq_res, 0, task);

        BUG_ON(ret == -EAGAIN);
        rpc_call_start(task);
        dprintk("<-- %s\n", __func__);
}

/*
 * Called from nfs4_state_manager thread for session setup, so don't recover
 * from sequence operation or clientid errors.
 */
static void nfs4_get_lease_time_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_get_lease_time_data *data =
                        (struct nfs4_get_lease_time_data *)calldata;

        dprintk("--> %s\n", __func__);
        nfs41_sequence_done(data->clp, &data->res->lr_seq_res, task->tk_status);
        switch (task->tk_status) {
        case -NFS4ERR_DELAY:
        case -NFS4ERR_GRACE:
                dprintk("%s Retry: tk_status %d\n", __func__, task->tk_status);
                rpc_delay(task, NFS4_POLL_RETRY_MIN);
                task->tk_status = 0;
                nfs4_restart_rpc(task, data->clp);
                return;
        }
        nfs41_sequence_free_slot(data->clp, &data->res->lr_seq_res);
        dprintk("<-- %s\n", __func__);
}

struct rpc_call_ops nfs4_get_lease_time_ops = {
        .rpc_call_prepare = nfs4_get_lease_time_prepare,
        .rpc_call_done = nfs4_get_lease_time_done,
};

int nfs4_proc_get_lease_time(struct nfs_client *clp, struct nfs_fsinfo *fsinfo)
{
        struct rpc_task *task;
        struct nfs4_get_lease_time_args args;
        struct nfs4_get_lease_time_res res = {
                .lr_fsinfo = fsinfo,
        };
        struct nfs4_get_lease_time_data data = {
                .args = &args,
                .res = &res,
                .clp = clp,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GET_LEASE_TIME],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        struct rpc_task_setup task_setup = {
                .rpc_client = clp->cl_rpcclient,
                .rpc_message = &msg,
                .callback_ops = &nfs4_get_lease_time_ops,
                .callback_data = &data
        };
        int status;

        res.lr_seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        dprintk("--> %s\n", __func__);
        task = rpc_run_task(&task_setup);

        if (IS_ERR(task))
                status = PTR_ERR(task);
        else {
                status = task->tk_status;
                rpc_put_task(task);
        }
        dprintk("<-- %s return %d\n", __func__, status);

        return status;
}

/* Reset a slot table */
static int nfs4_reset_slot_table(struct nfs4_session *session)
{
        struct nfs4_slot_table *tbl = &session->fc_slot_table;
        int i, max_slots = session->fc_attrs.max_reqs;
        int old_max_slots = session->fc_slot_table.max_slots;
        int ret = 0;

        dprintk("--> %s: max_reqs=%u, tbl %p\n", __func__,
                session->fc_attrs.max_reqs, tbl);

        /* 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;
        }
        spin_lock(&tbl->slot_tbl_lock);
        for (i = 0; i < max_slots; ++i)
                tbl->slots[i].seq_nr = 1;
        tbl->highest_used_slotid = -1;
        spin_unlock(&tbl->slot_tbl_lock);
        dprintk("%s: tbl=%p slots=%p max_slots=%d\n", __func__,
                tbl, tbl->slots, tbl->max_slots);
out:
        dprintk("<-- %s: return %d\n", __func__, ret);
        return ret;
}

/*
 * Initialize slot table
 */
static int nfs4_init_slot_table(struct nfs4_session *session)
{
        struct nfs4_slot_table *tbl = &session->fc_slot_table;
        int i, max_slots = session->fc_attrs.max_reqs;
        struct nfs4_slot *slot;
        int ret = -ENOMEM;

        BUG_ON(max_slots > NFS4_MAX_SLOT_TABLE);

        dprintk("--> %s: max_reqs=%u\n", __func__,
                session->fc_attrs.max_reqs);

        slot = kcalloc(max_slots, sizeof(struct nfs4_slot), GFP_KERNEL);
        if (!slot)
                goto out;
        for (i = 0; i < max_slots; ++i)
                slot[i].seq_nr = 1;
        ret = 0;

        spin_lock(&tbl->slot_tbl_lock);
        if (tbl->slots != NULL) {
                spin_unlock(&tbl->slot_tbl_lock);
                dprintk("%s: slot table already initialized. tbl=%p slots=%p\n",
                        __func__, tbl, tbl->slots);
                WARN_ON(1);
                goto out_free;
        }
        tbl->max_slots = max_slots;
        tbl->slots = slot;
        tbl->highest_used_slotid = -1;  /* no slot is currently used */
        spin_unlock(&tbl->slot_tbl_lock);
        dprintk("%s: tbl=%p slots=%p max_slots=%d\n", __func__,
                tbl, tbl->slots, tbl->max_slots);
out:
        dprintk("<-- %s: return %d\n", __func__, ret);
        return ret;
out_free:
        kfree(slot);
        goto out;
}

/* Destroy the slot table */
static void nfs4_destroy_slot_table(struct nfs4_session *session)
{
        if (session->fc_slot_table.slots == NULL)
                return;
        kfree(session->fc_slot_table.slots);
        session->fc_slot_table.slots = NULL;
        return;
}

struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
{
        struct nfs4_session *session;
        struct nfs4_slot_table *tbl;

        session = kzalloc(sizeof(struct nfs4_session), GFP_KERNEL);
        if (!session)
                return NULL;

        set_bit(NFS4CLNT_SESSION_SETUP, &clp->cl_state);
        /*
         * The create session reply races with the server back
         * channel probe. Mark the client NFS_CS_SESSION_INITING
         * so that the client back channel can find the
         * nfs_client struct
         */
        clp->cl_cons_state = NFS_CS_SESSION_INITING;

        tbl = &session->fc_slot_table;
        spin_lock_init(&tbl->slot_tbl_lock);
        rpc_init_wait_queue(&tbl->slot_tbl_waitq, "Slot table");
        session->clp = clp;
        return session;
}

void nfs4_destroy_session(struct nfs4_session *session)
{
        nfs4_destroy_slot_table(session);
        kfree(session);
}

/*
 * Initialize the values to be used by the client in CREATE_SESSION
 * If nfs4_init_session set the fore channel request and response sizes,
 * use them.
 *
 * Set the back channel max_resp_sz_cached to zero to force the client to
 * always set csa_cachethis to FALSE because the current implementation
 * of the back channel DRC only supports caching the CB_SEQUENCE operation.
 */
static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args)
{
        struct nfs4_session *session = args->client->cl_session;
        unsigned int mxrqst_sz = session->fc_attrs.max_rqst_sz,
                     mxresp_sz = session->fc_attrs.max_resp_sz;

        if (mxrqst_sz == 0)
                mxrqst_sz = NFS_MAX_FILE_IO_SIZE;
        if (mxresp_sz == 0)
                mxresp_sz = NFS_MAX_FILE_IO_SIZE;
        /* Fore channel attributes */
        args->fc_attrs.headerpadsz = 0;
        args->fc_attrs.max_rqst_sz = mxrqst_sz;
        args->fc_attrs.max_resp_sz = mxresp_sz;
        args->fc_attrs.max_resp_sz_cached = mxresp_sz;
        args->fc_attrs.max_ops = NFS4_MAX_OPS;
        args->fc_attrs.max_reqs = session->clp->cl_rpcclient->cl_xprt->max_reqs;

        dprintk("%s: Fore Channel : max_rqst_sz=%u max_resp_sz=%u "
                "max_resp_sz_cached=%u max_ops=%u max_reqs=%u\n",
                __func__,
                args->fc_attrs.max_rqst_sz, args->fc_attrs.max_resp_sz,
                args->fc_attrs.max_resp_sz_cached, args->fc_attrs.max_ops,
                args->fc_attrs.max_reqs);

        /* Back channel attributes */
        args->bc_attrs.headerpadsz = 0;
        args->bc_attrs.max_rqst_sz = PAGE_SIZE;
        args->bc_attrs.max_resp_sz = PAGE_SIZE;
        args->bc_attrs.max_resp_sz_cached = 0;
        args->bc_attrs.max_ops = NFS4_MAX_BACK_CHANNEL_OPS;
        args->bc_attrs.max_reqs = 1;

        dprintk("%s: Back Channel : max_rqst_sz=%u max_resp_sz=%u "
                "max_resp_sz_cached=%u max_ops=%u max_reqs=%u\n",
                __func__,
                args->bc_attrs.max_rqst_sz, args->bc_attrs.max_resp_sz,
                args->bc_attrs.max_resp_sz_cached, args->bc_attrs.max_ops,
                args->bc_attrs.max_reqs);
}

static int _verify_channel_attr(char *chan, char *attr_name, u32 sent, u32 rcvd)
{
        if (rcvd <= sent)
                return 0;
        printk(KERN_WARNING "%s: Session INVALID: %s channel %s increased. "
                "sent=%u rcvd=%u\n", __func__, chan, attr_name, sent, rcvd);
        return -EINVAL;
}

#define _verify_fore_channel_attr(_name_) \
        _verify_channel_attr("fore", #_name_, \
                             args->fc_attrs._name_, \
                             session->fc_attrs._name_)

#define _verify_back_channel_attr(_name_) \
        _verify_channel_attr("back", #_name_, \
                             args->bc_attrs._name_, \
                             session->bc_attrs._name_)

/*
 * The server is not allowed to increase the fore channel header pad size,
 * maximum response size, or maximum number of operations.
 *
 * The back channel attributes are only negotiatied down: We send what the
 * (back channel) server insists upon.
 */
static int nfs4_verify_channel_attrs(struct nfs41_create_session_args *args,
                                     struct nfs4_session *session)
{
        int ret = 0;

        ret |= _verify_fore_channel_attr(headerpadsz);
        ret |= _verify_fore_channel_attr(max_resp_sz);
        ret |= _verify_fore_channel_attr(max_ops);

        ret |= _verify_back_channel_attr(headerpadsz);
        ret |= _verify_back_channel_attr(max_rqst_sz);
        ret |= _verify_back_channel_attr(max_resp_sz);
        ret |= _verify_back_channel_attr(max_resp_sz_cached);
        ret |= _verify_back_channel_attr(max_ops);
        ret |= _verify_back_channel_attr(max_reqs);

        return ret;
}

static int _nfs4_proc_create_session(struct nfs_client *clp)
{
        struct nfs4_session *session = clp->cl_session;
        struct nfs41_create_session_args args = {
                .client = clp,
                .cb_program = NFS4_CALLBACK,
        };
        struct nfs41_create_session_res res = {
                .client = clp,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CREATE_SESSION],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        int status;

        nfs4_init_channel_attrs(&args);
        args.flags = (SESSION4_PERSIST);

        status = rpc_call_sync(session->clp->cl_rpcclient, &msg, 0);

        if (!status)
                /* Verify the session's negotiated channel_attrs values */
                status = nfs4_verify_channel_attrs(&args, session);
        if (!status) {
                /* Increment the clientid slot sequence id */
                clp->cl_seqid++;
        }

        return status;
}

/*
 * Issues a CREATE_SESSION operation to the server.
 * It is the responsibility of the caller to verify the session is
 * expired before calling this routine.
 */
int nfs4_proc_create_session(struct nfs_client *clp, int reset)
{
        int status;
        unsigned *ptr;
        struct nfs_fsinfo fsinfo;
        struct nfs4_session *session = clp->cl_session;

        dprintk("--> %s clp=%p session=%p\n", __func__, clp, session);

        status = _nfs4_proc_create_session(clp);
        if (status)
                goto out;

        /* Init or reset the fore channel */
        if (reset)
                status = nfs4_reset_slot_table(session);
        else
                status = nfs4_init_slot_table(session);
        dprintk("fore channel slot table initialization returned %d\n", status);
        if (status)
                goto out;

        ptr = (unsigned *)&session->sess_id.data[0];
        dprintk("%s client>seqid %d sessionid %u:%u:%u:%u\n", __func__,
                clp->cl_seqid, ptr[0], ptr[1], ptr[2], ptr[3]);

        if (reset)
                /* Lease time is aleady set */
                goto out;

        /* Get the lease time */
        status = nfs4_proc_get_lease_time(clp, &fsinfo);
        if (status == 0) {
                /* Update lease time and schedule renewal */
                spin_lock(&clp->cl_lock);
                clp->cl_lease_time = fsinfo.lease_time * HZ;
                clp->cl_last_renewal = jiffies;
                clear_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
                spin_unlock(&clp->cl_lock);

                nfs4_schedule_state_renewal(clp);
        }
out:
        dprintk("<-- %s\n", __func__);
        return status;
}

/*
 * Issue the over-the-wire RPC DESTROY_SESSION.
 * The caller must serialize access to this routine.
 */
int nfs4_proc_destroy_session(struct nfs4_session *session)
{
        int status = 0;
        struct rpc_message msg;

        dprintk("--> nfs4_proc_destroy_session\n");

        /* session is still being setup */
        if (session->clp->cl_cons_state != NFS_CS_READY)
                return status;

        msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DESTROY_SESSION];
        msg.rpc_argp = session;
        msg.rpc_resp = NULL;
        msg.rpc_cred = NULL;
        status = rpc_call_sync(session->clp->cl_rpcclient, &msg, 0);

        if (status)
                printk(KERN_WARNING
                        "Got error %d from the server on DESTROY_SESSION. "
                        "Session has been destroyed regardless...\n", status);

        dprintk("<-- nfs4_proc_destroy_session\n");
        return status;
}

/*
 * Renew the cl_session lease.
 */
static int nfs4_proc_sequence(struct nfs_client *clp, struct rpc_cred *cred)
{
        struct nfs4_sequence_args args;
        struct nfs4_sequence_res res;

        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SEQUENCE],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };

        args.sa_cache_this = 0;

        return nfs4_call_sync_sequence(clp, clp->cl_rpcclient, &msg, &args,
                                       &res, 0);
}

void nfs41_sequence_call_done(struct rpc_task *task, void *data)
{
        struct nfs_client *clp = (struct nfs_client *)data;

        nfs41_sequence_done(clp, task->tk_msg.rpc_resp, task->tk_status);

        if (task->tk_status < 0) {
                dprintk("%s ERROR %d\n", __func__, task->tk_status);

                if (_nfs4_async_handle_error(task, NULL, clp, NULL)
                                                                == -EAGAIN) {
                        nfs4_restart_rpc(task, clp);
                        return;
                }
        }
        nfs41_sequence_free_slot(clp, task->tk_msg.rpc_resp);
        dprintk("%s rpc_cred %p\n", __func__, task->tk_msg.rpc_cred);

        put_rpccred(task->tk_msg.rpc_cred);
        kfree(task->tk_msg.rpc_argp);
        kfree(task->tk_msg.rpc_resp);

        dprintk("<-- %s\n", __func__);
}

static void nfs41_sequence_prepare(struct rpc_task *task, void *data)
{
        struct nfs_client *clp;
        struct nfs4_sequence_args *args;
        struct nfs4_sequence_res *res;

        clp = (struct nfs_client *)data;
        args = task->tk_msg.rpc_argp;
        res = task->tk_msg.rpc_resp;

        if (nfs4_setup_sequence(clp, args, res, 0, task))
                return;
        rpc_call_start(task);
}

static const struct rpc_call_ops nfs41_sequence_ops = {
        .rpc_call_done = nfs41_sequence_call_done,
        .rpc_call_prepare = nfs41_sequence_prepare,
};

static int nfs41_proc_async_sequence(struct nfs_client *clp,
                                     struct rpc_cred *cred)
{
        struct nfs4_sequence_args *args;
        struct nfs4_sequence_res *res;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SEQUENCE],
                .rpc_cred = cred,
        };

        args = kzalloc(sizeof(*args), GFP_KERNEL);
        if (!args)
                return -ENOMEM;
        res = kzalloc(sizeof(*res), GFP_KERNEL);
        if (!res) {
                kfree(args);
                return -ENOMEM;
        }
        res->sr_slotid = NFS4_MAX_SLOT_TABLE;
        msg.rpc_argp = args;
        msg.rpc_resp = res;

        return rpc_call_async(clp->cl_rpcclient, &msg, RPC_TASK_SOFT,
                              &nfs41_sequence_ops, (void *)clp);
}

#endif /* CONFIG_NFS_V4_1 */

struct nfs4_state_recovery_ops nfs4_reboot_recovery_ops = {
        .owner_flag_bit = NFS_OWNER_RECLAIM_REBOOT,
        .state_flag_bit = NFS_STATE_RECLAIM_REBOOT,
        .recover_open   = nfs4_open_reclaim,
        .recover_lock   = nfs4_lock_reclaim,
};

struct nfs4_state_recovery_ops nfs4_nograce_recovery_ops = {
        .owner_flag_bit = NFS_OWNER_RECLAIM_NOGRACE,
        .state_flag_bit = NFS_STATE_RECLAIM_NOGRACE,
        .recover_open   = nfs4_open_expired,
        .recover_lock   = nfs4_lock_expired,
};

static const struct inode_operations nfs4_file_inode_operations = {
        .permission     = nfs_permission,
        .getattr        = nfs_getattr,
        .setattr        = nfs_setattr,
        .getxattr       = nfs4_getxattr,
        .setxattr       = nfs4_setxattr,
        .listxattr      = nfs4_listxattr,
};

const struct nfs_rpc_ops nfs_v4_clientops = {
        .version        = 4,                    /* protocol version */
        .dentry_ops     = &nfs4_dentry_operations,
        .dir_inode_ops  = &nfs4_dir_inode_operations,
        .file_inode_ops = &nfs4_file_inode_operations,
        .getroot        = nfs4_proc_get_root,
        .getattr        = nfs4_proc_getattr,
        .setattr        = nfs4_proc_setattr,
        .lookupfh       = nfs4_proc_lookupfh,
        .lookup         = nfs4_proc_lookup,
        .access         = nfs4_proc_access,
        .readlink       = nfs4_proc_readlink,
        .create         = nfs4_proc_create,
        .remove         = nfs4_proc_remove,
        .unlink_setup   = nfs4_proc_unlink_setup,
        .unlink_done    = nfs4_proc_unlink_done,
        .rename         = nfs4_proc_rename,
        .link           = nfs4_proc_link,
        .symlink        = nfs4_proc_symlink,
        .mkdir          = nfs4_proc_mkdir,
        .rmdir          = nfs4_proc_remove,
        .readdir        = nfs4_proc_readdir,
        .mknod          = nfs4_proc_mknod,
        .statfs         = nfs4_proc_statfs,
        .fsinfo         = nfs4_proc_fsinfo,
        .pathconf       = nfs4_proc_pathconf,
        .set_capabilities = nfs4_server_capabilities,
        .decode_dirent  = nfs4_decode_dirent,
        .read_setup     = nfs4_proc_read_setup,
        .read_done      = nfs4_read_done,
        .write_setup    = nfs4_proc_write_setup,
        .write_done     = nfs4_write_done,
        .commit_setup   = nfs4_proc_commit_setup,
        .commit_done    = nfs4_commit_done,
        .lock           = nfs4_proc_lock,
        .clear_acl_cache = nfs4_zap_acl_attr,
        .close_context  = nfs4_close_context,
};

/*
 * Local variables:
 *  c-basic-offset: 8
 * End:
 */