Merge remote-tracking branch 'regulator/topic/max8998' into v3.9-rc8

[mirror_ubuntu-hirsute-kernel.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/delay.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/ratelimit.h>
#include <linux/printk.h>
#include <linux/slab.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/nfs_mount.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/nfs_idmap.h>
#include <linux/xattr.h>
#include <linux/utsname.h>
#include <linux/freezer.h>

#include "nfs4_fs.h"
#include "delegation.h"
#include "internal.h"
#include "iostat.h"
#include "callback.h"
#include "pnfs.h"
#include "netns.h"
#include "nfs4session.h"
#include "fscache.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_recover_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 void nfs_fixup_referral_attributes(struct nfs_fattr *fattr);
static int nfs4_proc_getattr(struct nfs_server *, struct nfs_fh *, struct nfs_fattr *);
static int _nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fattr *fattr);
static int nfs4_do_setattr(struct inode *inode, struct rpc_cred *cred,
                            struct nfs_fattr *fattr, struct iattr *sattr,
                            struct nfs4_state *state);
#ifdef CONFIG_NFS_V4_1
static int nfs41_test_stateid(struct nfs_server *, nfs4_stateid *);
static int nfs41_free_stateid(struct nfs_server *, nfs4_stateid *);
#endif
/* Prevent leaks of NFSv4 errors into userland */
static int nfs4_map_errors(int err)
{
        if (err >= -1000)
                return err;
        switch (err) {
        case -NFS4ERR_RESOURCE:
        case -NFS4ERR_LAYOUTTRYLATER:
        case -NFS4ERR_RECALLCONFLICT:
                return -EREMOTEIO;
        case -NFS4ERR_WRONGSEC:
                return -EPERM;
        case -NFS4ERR_BADOWNER:
        case -NFS4ERR_BADNAME:
                return -EINVAL;
        case -NFS4ERR_SHARE_DENIED:
                return -EACCES;
        case -NFS4ERR_MINOR_VERS_MISMATCH:
                return -EPROTONOSUPPORT;
        case -NFS4ERR_ACCESS:
                return -EACCES;
        default:
                dprintk("%s could not handle NFSv4 error %d\n",
                                __func__, -err);
                break;
        }
        return -EIO;
}

/*
 * This is our standard bitmap for GETATTR requests.
 */
const u32 nfs4_fattr_bitmap[3] = {
        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
};

static const u32 nfs4_pnfs_open_bitmap[3] = {
        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,
        FATTR4_WORD2_MDSTHRESHOLD
};

static const u32 nfs4_open_noattr_bitmap[3] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_FILEID,
};

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[3] = { FATTR4_WORD0_MAXFILESIZE
                        | FATTR4_WORD0_MAXREAD
                        | FATTR4_WORD0_MAXWRITE
                        | FATTR4_WORD0_LEASE_TIME,
                        FATTR4_WORD1_TIME_DELTA
                        | FATTR4_WORD1_FS_LAYOUT_TYPES,
                        FATTR4_WORD2_LAYOUT_BLKSIZE
};

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;

        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);
        
        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);
}

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;
        freezable_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(struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
{
        struct nfs_client *clp = server->nfs_client;
        struct nfs4_state *state = exception->state;
        struct inode *inode = exception->inode;
        int ret = errorcode;

        exception->retry = 0;
        switch(errorcode) {
                case 0:
                        return 0;
                case -NFS4ERR_OPENMODE:
                        if (inode && nfs4_have_delegation(inode, FMODE_READ)) {
                                nfs4_inode_return_delegation(inode);
                                exception->retry = 1;
                                return 0;
                        }
                        if (state == NULL)
                                break;
                        nfs4_schedule_stateid_recovery(server, state);
                        goto wait_on_recovery;
                case -NFS4ERR_DELEG_REVOKED:
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_BAD_STATEID:
                        if (state == NULL)
                                break;
                        nfs_remove_bad_delegation(state->inode);
                        nfs4_schedule_stateid_recovery(server, state);
                        goto wait_on_recovery;
                case -NFS4ERR_EXPIRED:
                        if (state != NULL)
                                nfs4_schedule_stateid_recovery(server, state);
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_STALE_CLIENTID:
                        nfs4_schedule_lease_recovery(clp);
                        goto wait_on_recovery;
#if defined(CONFIG_NFS_V4_1)
                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);
                        nfs4_schedule_session_recovery(clp->cl_session, errorcode);
                        goto wait_on_recovery;
#endif /* defined(CONFIG_NFS_V4_1) */
                case -NFS4ERR_FILE_OPEN:
                        if (exception->timeout > HZ) {
                                /* We have retried a decent amount, time to
                                 * fail
                                 */
                                ret = -EBUSY;
                                break;
                        }
                case -NFS4ERR_GRACE:
                case -NFS4ERR_DELAY:
                        ret = nfs4_delay(server->client, &exception->timeout);
                        if (ret != 0)
                                break;
                case -NFS4ERR_RETRY_UNCACHED_REP:
                case -NFS4ERR_OLD_STATEID:
                        exception->retry = 1;
                        break;
                case -NFS4ERR_BADOWNER:
                        /* The following works around a Linux server bug! */
                case -NFS4ERR_BADNAME:
                        if (server->caps & NFS_CAP_UIDGID_NOMAP) {
                                server->caps &= ~NFS_CAP_UIDGID_NOMAP;
                                exception->retry = 1;
                                printk(KERN_WARNING "NFS: v4 server %s "
                                                "does not accept raw "
                                                "uid/gids. "
                                                "Reenabling the idmapper.\n",
                                                server->nfs_client->cl_hostname);
                        }
        }
        /* We failed to handle the error */
        return nfs4_map_errors(ret);
wait_on_recovery:
        ret = nfs4_wait_clnt_recover(clp);
        if (ret == 0)
                exception->retry = 1;
        return ret;
}


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

static void renew_lease(const struct nfs_server *server, unsigned long timestamp)
{
        do_renew_lease(server->nfs_client, timestamp);
}

#if defined(CONFIG_NFS_V4_1)

static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res)
{
        struct nfs4_session *session;
        struct nfs4_slot_table *tbl;
        bool send_new_highest_used_slotid = false;

        if (!res->sr_slot) {
                /* just wake up the next guy waiting since
                 * we may have not consumed a slot after all */
                dprintk("%s: No slot\n", __func__);
                return;
        }
        tbl = res->sr_slot->table;
        session = tbl->session;

        spin_lock(&tbl->slot_tbl_lock);
        /* Be nice to the server: try to ensure that the last transmitted
         * value for highest_user_slotid <= target_highest_slotid
         */
        if (tbl->highest_used_slotid > tbl->target_highest_slotid)
                send_new_highest_used_slotid = true;

        if (nfs41_wake_and_assign_slot(tbl, res->sr_slot)) {
                send_new_highest_used_slotid = false;
                goto out_unlock;
        }
        nfs4_free_slot(tbl, res->sr_slot);

        if (tbl->highest_used_slotid != NFS4_NO_SLOT)
                send_new_highest_used_slotid = false;
out_unlock:
        spin_unlock(&tbl->slot_tbl_lock);
        res->sr_slot = NULL;
        if (send_new_highest_used_slotid)
                nfs41_server_notify_highest_slotid_update(session->clp);
}

static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)
{
        struct nfs4_session *session;
        struct nfs4_slot *slot;
        struct nfs_client *clp;
        bool interrupted = false;
        int ret = 1;

        /* don't increment the sequence number if the task wasn't sent */
        if (!RPC_WAS_SENT(task))
                goto out;

        slot = res->sr_slot;
        session = slot->table->session;

        if (slot->interrupted) {
                slot->interrupted = 0;
                interrupted = true;
        }

        /* Check the SEQUENCE operation status */
        switch (res->sr_status) {
        case 0:
                /* Update the slot's sequence and clientid lease timer */
                ++slot->seq_nr;
                clp = session->clp;
                do_renew_lease(clp, res->sr_timestamp);
                /* Check sequence flags */
                if (res->sr_status_flags != 0)
                        nfs4_schedule_lease_recovery(clp);
                nfs41_update_target_slotid(slot->table, slot, res);
                break;
        case 1:
                /*
                 * sr_status remains 1 if an RPC level error occurred.
                 * The server may or may not have processed the sequence
                 * operation..
                 * Mark the slot as having hosted an interrupted RPC call.
                 */
                slot->interrupted = 1;
                goto out;
        case -NFS4ERR_DELAY:
                /* The server detected a resend of the RPC call and
                 * returned NFS4ERR_DELAY as per Section 2.10.6.2
                 * of RFC5661.
                 */
                dprintk("%s: slot=%u seq=%u: Operation in progress\n",
                        __func__,
                        slot->slot_nr,
                        slot->seq_nr);
                goto out_retry;
        case -NFS4ERR_BADSLOT:
                /*
                 * The slot id we used was probably retired. Try again
                 * using a different slot id.
                 */
                goto retry_nowait;
        case -NFS4ERR_SEQ_MISORDERED:
                /*
                 * Was the last operation on this sequence interrupted?
                 * If so, retry after bumping the sequence number.
                 */
                if (interrupted) {
                        ++slot->seq_nr;
                        goto retry_nowait;
                }
                /*
                 * Could this slot have been previously retired?
                 * If so, then the server may be expecting seq_nr = 1!
                 */
                if (slot->seq_nr != 1) {
                        slot->seq_nr = 1;
                        goto retry_nowait;
                }
                break;
        case -NFS4ERR_SEQ_FALSE_RETRY:
                ++slot->seq_nr;
                goto retry_nowait;
        default:
                /* Just update the slot sequence no. */
                ++slot->seq_nr;
        }
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(res);
        return ret;
retry_nowait:
        if (rpc_restart_call_prepare(task)) {
                task->tk_status = 0;
                ret = 0;
        }
        goto out;
out_retry:
        if (!rpc_restart_call(task))
                goto out;
        rpc_delay(task, NFS4_POLL_RETRY_MAX);
        return 0;
}

static int nfs4_sequence_done(struct rpc_task *task,
                               struct nfs4_sequence_res *res)
{
        if (res->sr_slot == NULL)
                return 1;
        return nfs41_sequence_done(task, res);
}

static void nfs41_init_sequence(struct nfs4_sequence_args *args,
                struct nfs4_sequence_res *res, int cache_reply)
{
        args->sa_slot = NULL;
        args->sa_cache_this = 0;
        args->sa_privileged = 0;
        if (cache_reply)
                args->sa_cache_this = 1;
        res->sr_slot = NULL;
}

static void nfs4_set_sequence_privileged(struct nfs4_sequence_args *args)
{
        args->sa_privileged = 1;
}

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

        dprintk("--> %s\n", __func__);
        /* slot already allocated? */
        if (res->sr_slot != NULL)
                goto out_success;

        tbl = &session->fc_slot_table;

        task->tk_timeout = 0;

        spin_lock(&tbl->slot_tbl_lock);
        if (test_bit(NFS4_SESSION_DRAINING, &session->session_state) &&
            !args->sa_privileged) {
                /* The state manager will wait until the slot table is empty */
                dprintk("%s session is draining\n", __func__);
                goto out_sleep;
        }

        slot = nfs4_alloc_slot(tbl);
        if (IS_ERR(slot)) {
                /* If out of memory, try again in 1/4 second */
                if (slot == ERR_PTR(-ENOMEM))
                        task->tk_timeout = HZ >> 2;
                dprintk("<-- %s: no free slots\n", __func__);
                goto out_sleep;
        }
        spin_unlock(&tbl->slot_tbl_lock);

        args->sa_slot = slot;

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

        res->sr_slot = slot;
        res->sr_timestamp = jiffies;
        res->sr_status_flags = 0;
        /*
         * 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;
out_success:
        rpc_call_start(task);
        return 0;
out_sleep:
        /* Privileged tasks are queued with top priority */
        if (args->sa_privileged)
                rpc_sleep_on_priority(&tbl->slot_tbl_waitq, task,
                                NULL, RPC_PRIORITY_PRIVILEGED);
        else
                rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
        spin_unlock(&tbl->slot_tbl_lock);
        return -EAGAIN;
}
EXPORT_SYMBOL_GPL(nfs41_setup_sequence);

int nfs4_setup_sequence(const struct nfs_server *server,
                        struct nfs4_sequence_args *args,
                        struct nfs4_sequence_res *res,
                        struct rpc_task *task)
{
        struct nfs4_session *session = nfs4_get_session(server);
        int ret = 0;

        if (session == NULL) {
                rpc_call_start(task);
                goto out;
        }

        dprintk("--> %s clp %p session %p sr_slot %d\n",
                __func__, session->clp, session, res->sr_slot ?
                        res->sr_slot->slot_nr : -1);

        ret = nfs41_setup_sequence(session, args, res, task);
out:
        dprintk("<-- %s status=%d\n", __func__, ret);
        return ret;
}

struct nfs41_call_sync_data {
        const struct nfs_server *seq_server;
        struct nfs4_sequence_args *seq_args;
        struct nfs4_sequence_res *seq_res;
};

static void nfs41_call_sync_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs41_call_sync_data *data = calldata;
        struct nfs4_session *session = nfs4_get_session(data->seq_server);

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

        nfs41_setup_sequence(session, data->seq_args, data->seq_res, task);
}

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

        nfs41_sequence_done(task, data->seq_res);
}

static const 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 rpc_clnt *clnt,
                                   struct nfs_server *server,
                                   struct rpc_message *msg,
                                   struct nfs4_sequence_args *args,
                                   struct nfs4_sequence_res *res)
{
        int ret;
        struct rpc_task *task;
        struct nfs41_call_sync_data data = {
                .seq_server = server,
                .seq_args = args,
                .seq_res = res,
        };
        struct rpc_task_setup task_setup = {
                .rpc_client = clnt,
                .rpc_message = msg,
                .callback_ops = &nfs41_call_sync_ops,
                .callback_data = &data
        };

        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;
}

#else
static
void nfs41_init_sequence(struct nfs4_sequence_args *args,
                struct nfs4_sequence_res *res, int cache_reply)
{
}

static void nfs4_set_sequence_privileged(struct nfs4_sequence_args *args)
{
}


static int nfs4_sequence_done(struct rpc_task *task,
                               struct nfs4_sequence_res *res)
{
        return 1;
}
#endif /* CONFIG_NFS_V4_1 */

static
int _nfs4_call_sync(struct rpc_clnt *clnt,
                    struct nfs_server *server,
                    struct rpc_message *msg,
                    struct nfs4_sequence_args *args,
                    struct nfs4_sequence_res *res)
{
        return rpc_call_sync(clnt, msg, 0);
}

static
int nfs4_call_sync(struct rpc_clnt *clnt,
                   struct nfs_server *server,
                   struct rpc_message *msg,
                   struct nfs4_sequence_args *args,
                   struct nfs4_sequence_res *res,
                   int cache_reply)
{
        nfs41_init_sequence(args, res, cache_reply);
        return server->nfs_client->cl_mvops->call_sync(clnt, server, msg,
                                                args, 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_INVALID_DATA;
        if (!cinfo->atomic || cinfo->before != dir->i_version)
                nfs_force_lookup_revalidate(dir);
        dir->i_version = cinfo->after;
        nfs_fscache_invalidate(dir);
        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 nfs4_string owner_name;
        struct nfs4_string group_name;
        struct nfs_fattr f_attr;
        struct dentry *dir;
        struct dentry *dentry;
        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.seqid = p->o_arg.seqid;
        p->c_res.seqid = p->c_arg.seqid;
        p->o_res.server = p->o_arg.server;
        p->o_res.access_request = p->o_arg.access;
        nfs_fattr_init(&p->f_attr);
        nfs_fattr_init_names(&p->f_attr, &p->owner_name, &p->group_name);
}

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

        p = kzalloc(sizeof(*p), gfp_mask);
        if (p == NULL)
                goto err;
        p->o_arg.seqid = nfs_alloc_seqid(&sp->so_seqid, gfp_mask);
        if (p->o_arg.seqid == NULL)
                goto err_free;
        nfs_sb_active(dentry->d_sb);
        p->dentry = dget(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);
        /* don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
         * will return permission denied for all bits until close */
        if (!(flags & O_EXCL)) {
                /* ask server to check for all possible rights as results
                 * are cached */
                p->o_arg.access = NFS4_ACCESS_READ | NFS4_ACCESS_MODIFY |
                                  NFS4_ACCESS_EXTEND | NFS4_ACCESS_EXECUTE;
        }
        p->o_arg.clientid = server->nfs_client->cl_clientid;
        p->o_arg.id.create_time = ktime_to_ns(sp->so_seqid.create_time);
        p->o_arg.id.uniquifier = sp->so_seqid.owner_id;
        p->o_arg.name = &dentry->d_name;
        p->o_arg.server = server;
        p->o_arg.bitmask = server->attr_bitmask;
        p->o_arg.open_bitmap = &nfs4_fattr_bitmap[0];
        p->o_arg.claim = NFS4_OPEN_CLAIM_NULL;
        if (attrs != NULL && attrs->ia_valid != 0) {
                __be32 verf[2];

                p->o_arg.u.attrs = &p->attrs;
                memcpy(&p->attrs, attrs, sizeof(p->attrs));

                verf[0] = jiffies;
                verf[1] = current->pid;
                memcpy(p->o_arg.u.verifier.data, verf,
                                sizeof(p->o_arg.u.verifier.data));
        }
        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);
        struct super_block *sb = p->dentry->d_sb;

        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);
        dput(p->dentry);
        nfs_sb_deactive(sb);
        nfs_fattr_free_names(&p->f_attr);
        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|O_TRUNC))
                goto out;
        switch (mode & (FMODE_READ|FMODE_WRITE)) {
                case FMODE_READ:
                        ret |= test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0
                                && state->n_rdonly != 0;
                        break;
                case FMODE_WRITE:
                        ret |= test_bit(NFS_O_WRONLY_STATE, &state->flags) != 0
                                && state->n_wronly != 0;
                        break;
                case FMODE_READ|FMODE_WRITE:
                        ret |= test_bit(NFS_O_RDWR_STATE, &state->flags) != 0
                                && state->n_rdwr != 0;
        }
out:
        return ret;
}

static int can_open_delegated(struct nfs_delegation *delegation, fmode_t fmode)
{
        if (delegation == NULL)
                return 0;
        if ((delegation->type & fmode) != fmode)
                return 0;
        if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags))
                return 0;
        if (test_bit(NFS_DELEGATION_RETURNING, &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)
                nfs4_stateid_copy(&state->stateid, stateid);
        nfs4_stateid_copy(&state->open_stateid, stateid);
        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) {
                nfs4_stateid_copy(&state->stateid, deleg_stateid);
                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 ||
           test_bit(NFS_DELEGATION_RETURNING, &deleg_cur->flags) ||
            (deleg_cur->type & fmode) != fmode)
                goto no_delegation_unlock;

        if (delegation == NULL)
                delegation = &deleg_cur->stateid;
        else if (!nfs4_stateid_match(&deleg_cur->stateid, delegation))
                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();
        nfs4_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|O_TRUNC);
        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 (!can_open_delegated(delegation, fmode)) {
                        rcu_read_unlock();
                        break;
                }
                /* Save the delegation */
                nfs4_stateid_copy(&stateid, &delegation->stateid);
                rcu_read_unlock();
                nfs_release_seqid(opendata->o_arg.seqid);
                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 void
nfs4_opendata_check_deleg(struct nfs4_opendata *data, struct nfs4_state *state)
{
        struct nfs_client *clp = NFS_SERVER(state->inode)->nfs_client;
        struct nfs_delegation *delegation;
        int delegation_flags = 0;

        rcu_read_lock();
        delegation = rcu_dereference(NFS_I(state->inode)->delegation);
        if (delegation)
                delegation_flags = delegation->flags;
        rcu_read_unlock();
        if (data->o_arg.claim == NFS4_OPEN_CLAIM_DELEGATE_CUR) {
                pr_err_ratelimited("NFS: Broken NFSv4 server %s is "
                                   "returning a delegation for "
                                   "OPEN(CLAIM_DELEGATE_CUR)\n",
                                   clp->cl_hostname);
        } else 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);
}

/*
 * Check the inode attributes against the CLAIM_PREVIOUS returned attributes
 * and update the nfs4_state.
 */
static struct nfs4_state *
_nfs4_opendata_reclaim_to_nfs4_state(struct nfs4_opendata *data)
{
        struct inode *inode = data->state->inode;
        struct nfs4_state *state = data->state;
        int ret;

        if (!data->rpc_done) {
                ret = data->rpc_status;
                goto err;
        }

        ret = -ESTALE;
        if (!(data->f_attr.valid & NFS_ATTR_FATTR_TYPE) ||
            !(data->f_attr.valid & NFS_ATTR_FATTR_FILEID) ||
            !(data->f_attr.valid & NFS_ATTR_FATTR_CHANGE))
                goto err;

        ret = -ENOMEM;
        state = nfs4_get_open_state(inode, data->owner);
        if (state == NULL)
                goto err;

        ret = nfs_refresh_inode(inode, &data->f_attr);
        if (ret)
                goto err;

        if (data->o_res.delegation_type != 0)
                nfs4_opendata_check_deleg(data, state);
        update_open_stateid(state, &data->o_res.stateid, NULL,
                            data->o_arg.fmode);

        return state;
err:
        return ERR_PTR(ret);

}

static struct nfs4_state *
_nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
{
        struct inode *inode;
        struct nfs4_state *state = NULL;
        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)
                nfs4_opendata_check_deleg(data, state);
        update_open_stateid(state, &data->o_res.stateid, NULL,
                        data->o_arg.fmode);
        iput(inode);
out:
        nfs_release_seqid(data->o_arg.seqid);
        return state;
err_put_inode:
        iput(inode);
err:
        return ERR_PTR(ret);
}

static struct nfs4_state *
nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
{
        if (data->o_arg.claim == NFS4_OPEN_CLAIM_PREVIOUS)
                return _nfs4_opendata_reclaim_to_nfs4_state(data);
        return _nfs4_opendata_to_nfs4_state(data);
}

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->dentry, state->owner, 0, 0, NULL, GFP_NOFS);
        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_recover_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(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) {
                clear_bit(NFS_O_RDWR_STATE, &state->flags);
                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) {
                clear_bit(NFS_O_WRONLY_STATE, &state->flags);
                ret = nfs4_open_recover_helper(opendata, FMODE_WRITE, &newstate);
                if (ret != 0)
                        return ret;
                if (newstate != state)
                        return -ESTALE;
        }
        if (state->n_rdonly != 0) {
                clear_bit(NFS_O_RDONLY_STATE, &state->flags);
                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 &&
            !nfs4_stateid_match(&state->stateid, &state->open_stateid)) {
                write_seqlock(&state->seqlock);
                if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                        nfs4_stateid_copy(&state->stateid, &state->open_stateid);
                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;
        nfs4_stateid_copy(&opendata->o_arg.u.delegation, stateid);
        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:
                        case -ENOENT:
                        case -ESTALE:
                                goto out;
                        case -NFS4ERR_BADSESSION:
                        case -NFS4ERR_BADSLOT:
                        case -NFS4ERR_BAD_HIGH_SLOT:
                        case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
                        case -NFS4ERR_DEADSESSION:
                                set_bit(NFS_DELEGATED_STATE, &state->flags);
                                nfs4_schedule_session_recovery(server->nfs_client->cl_session, err);
                                err = -EAGAIN;
                                goto out;
                        case -NFS4ERR_STALE_CLIENTID:
                        case -NFS4ERR_STALE_STATEID:
                                set_bit(NFS_DELEGATED_STATE, &state->flags);
                        case -NFS4ERR_EXPIRED:
                                /* Don't recall a delegation if it was lost */
                                nfs4_schedule_lease_recovery(server->nfs_client);
                                err = -EAGAIN;
                                goto out;
                        case -NFS4ERR_DELEG_REVOKED:
                        case -NFS4ERR_ADMIN_REVOKED:
                        case -NFS4ERR_BAD_STATEID:
                                nfs_inode_find_state_and_recover(state->inode,
                                                stateid);
                                nfs4_schedule_stateid_recovery(server, state);
                        case -ENOMEM:
                                err = 0;
                                goto out;
                }
                set_bit(NFS_DELEGATED_STATE, &state->flags);
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
out:
        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 (data->rpc_status == 0) {
                nfs4_stateid_copy(&data->o_res.stateid, &data->c_res.stateid);
                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(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)
                goto out_wait;
        /*
         * 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 (data->o_arg.claim != NFS4_OPEN_CLAIM_DELEGATE_CUR &&
                    can_open_delegated(delegation, data->o_arg.fmode))
                        goto unlock_no_action;
                rcu_read_unlock();
        }
        /* Update client id. */
        data->o_arg.clientid = sp->so_server->nfs_client->cl_clientid;
        if (data->o_arg.claim == NFS4_OPEN_CLAIM_PREVIOUS) {
                task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_NOATTR];
                data->o_arg.open_bitmap = &nfs4_open_noattr_bitmap[0];
                nfs_copy_fh(&data->o_res.fh, data->o_arg.fh);
        }
        data->timestamp = jiffies;
        if (nfs4_setup_sequence(data->o_arg.server,
                                &data->o_arg.seq_args,
                                &data->o_res.seq_res,
                                task) != 0)
                nfs_release_seqid(data->o_arg.seqid);
        return;
unlock_no_action:
        rcu_read_unlock();
out_no_action:
        task->tk_action = NULL;
out_wait:
        nfs4_sequence_done(task, &data->o_res.seq_res);
}

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

        data->rpc_status = task->tk_status;

        if (!nfs4_sequence_done(task, &data->o_res.seq_res))
                return;

        if (task->tk_status == 0) {
                if (data->o_res.f_attr->valid & NFS_ATTR_FATTR_TYPE) {
                        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(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,
};

static int nfs4_run_open_task(struct nfs4_opendata *data, int isrecover)
{
        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;

        nfs41_init_sequence(&o_arg->seq_args, &o_res->seq_res, 1);
        kref_get(&data->kref);
        data->rpc_done = 0;
        data->rpc_status = 0;
        data->cancelled = 0;
        if (isrecover)
                nfs4_set_sequence_privileged(&o_arg->seq_args);
        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 int _nfs4_recover_proc_open(struct nfs4_opendata *data)
{
        struct inode *dir = data->dir->d_inode;
        struct nfs_openres *o_res = &data->o_res;
        int status;

        status = nfs4_run_open_task(data, 1);
        if (status != 0 || !data->rpc_done)
                return status;

        nfs_fattr_map_and_free_names(NFS_SERVER(dir), &data->f_attr);

        if (o_res->rflags & NFS4_OPEN_RESULT_CONFIRM) {
                status = _nfs4_proc_open_confirm(data);
                if (status != 0)
                        return status;
        }

        return status;
}

static int nfs4_opendata_access(struct rpc_cred *cred,
                                struct nfs4_opendata *opendata,
                                struct nfs4_state *state, fmode_t fmode,
                                int openflags)
{
        struct nfs_access_entry cache;
        u32 mask;

        /* access call failed or for some reason the server doesn't
         * support any access modes -- defer access call until later */
        if (opendata->o_res.access_supported == 0)
                return 0;

        mask = 0;
        /* don't check MAY_WRITE - a newly created file may not have
         * write mode bits, but POSIX allows the creating process to write.
         * use openflags to check for exec, because fmode won't
         * always have FMODE_EXEC set when file open for exec. */
        if (openflags & __FMODE_EXEC) {
                /* ONLY check for exec rights */
                mask = MAY_EXEC;
        } else if (fmode & FMODE_READ)
                mask = MAY_READ;

        cache.cred = cred;
        cache.jiffies = jiffies;
        nfs_access_set_mask(&cache, opendata->o_res.access_result);
        nfs_access_add_cache(state->inode, &cache);

        if ((mask & ~cache.mask & (MAY_READ | MAY_EXEC)) == 0)
                return 0;

        /* even though OPEN succeeded, access is denied. Close the file */
        nfs4_close_state(state, fmode);
        return -EACCES;
}

/*
 * 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;
        int status;

        status = nfs4_run_open_task(data, 0);
        if (!data->rpc_done)
                return status;
        if (status != 0) {
                if (status == -NFS4ERR_BADNAME &&
                                !(o_arg->open_flags & O_CREAT))
                        return -ENOENT;
                return status;
        }

        nfs_fattr_map_and_free_names(server, &data->f_attr);

        if (o_arg->open_flags & O_CREAT)
                update_changeattr(dir, &o_res->cinfo);
        if ((o_res->rflags & NFS4_OPEN_RESULT_LOCKTYPE_POSIX) == 0)
                server->caps &= ~NFS_CAP_POSIX_LOCK;
        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)
{
        return nfs4_client_recover_expired_lease(server->nfs_client);
}

/*
 * 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->dentry);
        nfs4_opendata_put(opendata);
        return ret;
}

static 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);
                switch (err) {
                default:
                        goto out;
                case -NFS4ERR_GRACE:
                case -NFS4ERR_DELAY:
                        nfs4_handle_exception(server, err, &exception);
                        err = 0;
                }
        } while (exception.retry);
out:
        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;
}

#if defined(CONFIG_NFS_V4_1)
static void nfs41_clear_delegation_stateid(struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        nfs4_stateid *stateid = &state->stateid;
        int status;

        /* If a state reset has been done, test_stateid is unneeded */
        if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                return;

        status = nfs41_test_stateid(server, stateid);
        if (status != NFS_OK) {
                /* Free the stateid unless the server explicitly
                 * informs us the stateid is unrecognized. */
                if (status != -NFS4ERR_BAD_STATEID)
                        nfs41_free_stateid(server, stateid);
                nfs_remove_bad_delegation(state->inode);

                write_seqlock(&state->seqlock);
                nfs4_stateid_copy(&state->stateid, &state->open_stateid);
                write_sequnlock(&state->seqlock);
                clear_bit(NFS_DELEGATED_STATE, &state->flags);
        }
}

/**
 * nfs41_check_open_stateid - possibly free an open stateid
 *
 * @state: NFSv4 state for an inode
 *
 * Returns NFS_OK if recovery for this stateid is now finished.
 * Otherwise a negative NFS4ERR value is returned.
 */
static int nfs41_check_open_stateid(struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        nfs4_stateid *stateid = &state->open_stateid;
        int status;

        /* If a state reset has been done, test_stateid is unneeded */
        if ((test_bit(NFS_O_RDONLY_STATE, &state->flags) == 0) &&
            (test_bit(NFS_O_WRONLY_STATE, &state->flags) == 0) &&
            (test_bit(NFS_O_RDWR_STATE, &state->flags) == 0))
                return -NFS4ERR_BAD_STATEID;

        status = nfs41_test_stateid(server, stateid);
        if (status != NFS_OK) {
                /* Free the stateid unless the server explicitly
                 * informs us the stateid is unrecognized. */
                if (status != -NFS4ERR_BAD_STATEID)
                        nfs41_free_stateid(server, stateid);

                clear_bit(NFS_O_RDONLY_STATE, &state->flags);
                clear_bit(NFS_O_WRONLY_STATE, &state->flags);
                clear_bit(NFS_O_RDWR_STATE, &state->flags);
        }
        return status;
}

static int nfs41_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        int status;

        nfs41_clear_delegation_stateid(state);
        status = nfs41_check_open_stateid(state);
        if (status != NFS_OK)
                status = nfs4_open_expired(sp, state);
        return status;
}
#endif

/*
 * 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;
}

static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata,
                fmode_t fmode,
                int flags,
                struct nfs4_state **res)
{
        struct nfs4_state_owner *sp = opendata->owner;
        struct nfs_server *server = sp->so_server;
        struct nfs4_state *state;
        unsigned int seq;
        int ret;

        seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);

        ret = _nfs4_proc_open(opendata);
        if (ret != 0)
                goto out;

        state = nfs4_opendata_to_nfs4_state(opendata);
        ret = PTR_ERR(state);
        if (IS_ERR(state))
                goto out;
        if (server->caps & NFS_CAP_POSIX_LOCK)
                set_bit(NFS_STATE_POSIX_LOCKS, &state->flags);

        ret = nfs4_opendata_access(sp->so_cred, opendata, state, fmode, flags);
        if (ret != 0)
                goto out;

        if (read_seqcount_retry(&sp->so_reclaim_seqcount, seq)) {
                nfs4_schedule_stateid_recovery(server, state);
                nfs4_wait_clnt_recover(server->nfs_client);
        }
        *res = state;
out:
        return ret;
}

/*
 * Returns a referenced nfs4_state
 */
static int _nfs4_do_open(struct inode *dir,
                        struct dentry *dentry,
                        fmode_t fmode,
                        int flags,
                        struct iattr *sattr,
                        struct rpc_cred *cred,
                        struct nfs4_state **res,
                        struct nfs4_threshold **ctx_th)
{
        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;
        sp = nfs4_get_state_owner(server, cred, GFP_KERNEL);
        if (sp == NULL) {
                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 (dentry->d_inode != NULL)
                nfs4_return_incompatible_delegation(dentry->d_inode, fmode);
        status = -ENOMEM;
        opendata = nfs4_opendata_alloc(dentry, sp, fmode, flags, sattr, GFP_KERNEL);
        if (opendata == NULL)
                goto err_put_state_owner;

        if (ctx_th && server->attr_bitmask[2] & FATTR4_WORD2_MDSTHRESHOLD) {
                opendata->f_attr.mdsthreshold = pnfs_mdsthreshold_alloc();
                if (!opendata->f_attr.mdsthreshold)
                        goto err_opendata_put;
                opendata->o_arg.open_bitmap = &nfs4_pnfs_open_bitmap[0];
        }
        if (dentry->d_inode != NULL)
                opendata->state = nfs4_get_open_state(dentry->d_inode, sp);

        status = _nfs4_open_and_get_state(opendata, fmode, flags, &state);
        if (status != 0)
                goto err_opendata_put;

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

                nfs_fattr_init(opendata->o_res.f_attr);
                status = nfs4_do_setattr(state->inode, cred,
                                opendata->o_res.f_attr, sattr,
                                state);
                if (status == 0)
                        nfs_setattr_update_inode(state->inode, sattr);
                nfs_post_op_update_inode(state->inode, opendata->o_res.f_attr);
        }

        if (pnfs_use_threshold(ctx_th, opendata->f_attr.mdsthreshold, server))
                *ctx_th = opendata->f_attr.mdsthreshold;
        else
                kfree(opendata->f_attr.mdsthreshold);
        opendata->f_attr.mdsthreshold = NULL;

        nfs4_opendata_put(opendata);
        nfs4_put_state_owner(sp);
        *res = state;
        return 0;
err_opendata_put:
        kfree(opendata->f_attr.mdsthreshold);
        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 dentry *dentry,
                                        fmode_t fmode,
                                        int flags,
                                        struct iattr *sattr,
                                        struct rpc_cred *cred,
                                        struct nfs4_threshold **ctx_th)
{
        struct nfs4_exception exception = { };
        struct nfs4_state *res;
        int status;

        fmode &= FMODE_READ|FMODE_WRITE|FMODE_EXEC;
        do {
                status = _nfs4_do_open(dir, dentry, fmode, flags, sattr, cred,
                                       &res, ctx_th);
                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) {
                        pr_warn_ratelimited("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 (state != NULL) {
                struct nfs_lockowner lockowner = {
                        .l_owner = current->files,
                        .l_pid = current->tgid,
                };
                nfs4_select_rw_stateid(&arg.stateid, state, FMODE_WRITE,
                                &lockowner);
        } else if (nfs4_copy_delegation_stateid(&arg.stateid, inode,
                                FMODE_WRITE)) {
                /* Use that stateid */
        } else
                nfs4_stateid_copy(&arg.stateid, &zero_stateid);

        status = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_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 = {
                .state = state,
                .inode = inode,
        };
        int err;
        do {
                err = _nfs4_do_setattr(inode, cred, fattr, sattr, state);
                switch (err) {
                case -NFS4ERR_OPENMODE:
                        if (state && !(state->state & FMODE_WRITE)) {
                                err = -EBADF;
                                if (sattr->ia_valid & ATTR_OPEN)
                                        err = -EACCES;
                                goto out;
                        }
                }
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
out:
        return err;
}

struct nfs4_closedata {
        struct inode *inode;
        struct nfs4_state *state;
        struct nfs_closeargs arg;
        struct nfs_closeres res;
        struct nfs_fattr fattr;
        unsigned long timestamp;
        bool roc;
        u32 roc_barrier;
};

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

        if (calldata->roc)
                pnfs_roc_release(calldata->state->inode);
        nfs4_put_open_state(calldata->state);
        nfs_free_seqid(calldata->arg.seqid);
        nfs4_put_state_owner(sp);
        nfs_sb_deactive(sb);
        kfree(calldata);
}

static void nfs4_close_clear_stateid_flags(struct nfs4_state *state,
                fmode_t fmode)
{
        spin_lock(&state->owner->so_lock);
        if (!(fmode & FMODE_READ))
                clear_bit(NFS_O_RDONLY_STATE, &state->flags);
        if (!(fmode & FMODE_WRITE))
                clear_bit(NFS_O_WRONLY_STATE, &state->flags);
        clear_bit(NFS_O_RDWR_STATE, &state->flags);
        spin_unlock(&state->owner->so_lock);
}

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);

        dprintk("%s: begin!\n", __func__);
        if (!nfs4_sequence_done(task, &calldata->res.seq_res))
                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:
                        if (calldata->roc)
                                pnfs_roc_set_barrier(state->inode,
                                                     calldata->roc_barrier);
                        nfs_set_open_stateid(state, &calldata->res.stateid, 0);
                        renew_lease(server, calldata->timestamp);
                        nfs4_close_clear_stateid_flags(state,
                                        calldata->arg.fmode);
                        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)
                                rpc_restart_call_prepare(task);
        }
        nfs_release_seqid(calldata->arg.seqid);
        nfs_refresh_inode(calldata->inode, calldata->res.fattr);
        dprintk("%s: done, ret = %d!\n", __func__, task->tk_status);
}

static void nfs4_close_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_closedata *calldata = data;
        struct nfs4_state *state = calldata->state;
        struct inode *inode = calldata->inode;
        int call_close = 0;

        dprintk("%s: begin!\n", __func__);
        if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)
                goto out_wait;

        task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
        calldata->arg.fmode = FMODE_READ|FMODE_WRITE;
        spin_lock(&state->owner->so_lock);
        /* Calculate the change in open mode */
        if (state->n_rdwr == 0) {
                if (state->n_rdonly == 0) {
                        call_close |= test_bit(NFS_O_RDONLY_STATE, &state->flags);
                        call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
                        calldata->arg.fmode &= ~FMODE_READ;
                }
                if (state->n_wronly == 0) {
                        call_close |= test_bit(NFS_O_WRONLY_STATE, &state->flags);
                        call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
                        calldata->arg.fmode &= ~FMODE_WRITE;
                }
        }
        spin_unlock(&state->owner->so_lock);

        if (!call_close) {
                /* Note: exit _without_ calling nfs4_close_done */
                goto out_no_action;
        }

        if (calldata->arg.fmode == 0) {
                task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE];
                if (calldata->roc &&
                    pnfs_roc_drain(inode, &calldata->roc_barrier, task))
                        goto out_wait;
        }

        nfs_fattr_init(calldata->res.fattr);
        calldata->timestamp = jiffies;
        if (nfs4_setup_sequence(NFS_SERVER(inode),
                                &calldata->arg.seq_args,
                                &calldata->res.seq_res,
                                task) != 0)
                nfs_release_seqid(calldata->arg.seqid);
        dprintk("%s: done!\n", __func__);
        return;
out_no_action:
        task->tk_action = NULL;
out_wait:
        nfs4_sequence_done(task, &calldata->res.seq_res);
}

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 nfs4_state *state, gfp_t gfp_mask, 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_mask);
        if (calldata == NULL)
                goto out;
        nfs41_init_sequence(&calldata->arg.seq_args, &calldata->res.seq_res, 1);
        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, gfp_mask);
        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->roc = pnfs_roc(state->inode);
        nfs_sb_active(calldata->inode->i_sb);

        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 struct inode *
nfs4_atomic_open(struct inode *dir, struct nfs_open_context *ctx, int open_flags, struct iattr *attr)
{
        struct nfs4_state *state;

        /* Protect against concurrent sillydeletes */
        state = nfs4_do_open(dir, ctx->dentry, ctx->mode, open_flags, attr,
                             ctx->cred, &ctx->mdsthreshold);
        if (IS_ERR(state))
                return ERR_CAST(state);
        ctx->state = state;
        return igrab(state->inode);
}

static void nfs4_close_context(struct nfs_open_context *ctx, int is_sync)
{
        if (ctx->state == NULL)
                return;
        if (is_sync)
                nfs4_close_sync(ctx->state, ctx->mode);
        else
                nfs4_close_state(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->client, server, &msg, &args.seq_args, &res.seq_res, 0);
        if (status == 0) {
                memcpy(server->attr_bitmask, res.attr_bitmask, sizeof(server->attr_bitmask));
                server->caps &= ~(NFS_CAP_ACLS|NFS_CAP_HARDLINKS|
                                NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
                                NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|
                                NFS_CAP_OWNER_GROUP|NFS_CAP_ATIME|
                                NFS_CAP_CTIME|NFS_CAP_MTIME);
                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;
                if (res.attr_bitmask[0] & FATTR4_WORD0_FILEID)
                        server->caps |= NFS_CAP_FILEID;
                if (res.attr_bitmask[1] & FATTR4_WORD1_MODE)
                        server->caps |= NFS_CAP_MODE;
                if (res.attr_bitmask[1] & FATTR4_WORD1_NUMLINKS)
                        server->caps |= NFS_CAP_NLINK;
                if (res.attr_bitmask[1] & FATTR4_WORD1_OWNER)
                        server->caps |= NFS_CAP_OWNER;
                if (res.attr_bitmask[1] & FATTR4_WORD1_OWNER_GROUP)
                        server->caps |= NFS_CAP_OWNER_GROUP;
                if (res.attr_bitmask[1] & FATTR4_WORD1_TIME_ACCESS)
                        server->caps |= NFS_CAP_ATIME;
                if (res.attr_bitmask[1] & FATTR4_WORD1_TIME_METADATA)
                        server->caps |= NFS_CAP_CTIME;
                if (res.attr_bitmask[1] & FATTR4_WORD1_TIME_MODIFY)
                        server->caps |= NFS_CAP_MTIME;

                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;
                server->fh_expire_type = res.fh_expire_type;
        }

        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->client, server, &msg, &args.seq_args, &res.seq_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_lookup_root(server, fhandle, info);
                switch (err) {
                case 0:
                case -NFS4ERR_WRONGSEC:
                        goto out;
                default:
                        err = nfs4_handle_exception(server, err, &exception);
                }
        } while (exception.retry);
out:
        return err;
}

static int nfs4_lookup_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
                                struct nfs_fsinfo *info, rpc_authflavor_t flavor)
{
        struct rpc_auth *auth;
        int ret;

        auth = rpcauth_create(flavor, server->client);
        if (IS_ERR(auth)) {
                ret = -EIO;
                goto out;
        }
        ret = nfs4_lookup_root(server, fhandle, info);
out:
        return ret;
}

static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
                              struct nfs_fsinfo *info)
{
        int i, len, status = 0;
        rpc_authflavor_t flav_array[NFS_MAX_SECFLAVORS];

        len = rpcauth_list_flavors(flav_array, ARRAY_SIZE(flav_array));
        if (len < 0)
                return len;

        for (i = 0; i < len; i++) {
                /* AUTH_UNIX is the default flavor if none was specified,
                 * thus has already been tried. */
                if (flav_array[i] == RPC_AUTH_UNIX)
                        continue;

                status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
                if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
                        continue;
                break;
        }
        /*
         * -EACCESS could mean that the user doesn't have correct permissions
         * to access the mount.  It could also mean that we tried to mount
         * with a gss auth flavor, but rpc.gssd isn't running.  Either way,
         * existing mount programs don't handle -EACCES very well so it should
         * be mapped to -EPERM instead.
         */
        if (status == -EACCES)
                status = -EPERM;
        return status;
}

/*
 * get the file handle for the "/" directory on the server
 */
int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
                         struct nfs_fsinfo *info)
{
        int minor_version = server->nfs_client->cl_minorversion;
        int status = nfs4_lookup_root(server, fhandle, info);
        if ((status == -NFS4ERR_WRONGSEC) && !(server->flags & NFS_MOUNT_SECFLAVOUR))
                /*
                 * A status of -NFS4ERR_WRONGSEC will be mapped to -EPERM
                 * by nfs4_map_errors() as this function exits.
                 */
                status = nfs_v4_minor_ops[minor_version]->find_root_sec(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);
}

static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *mntfh,
                              struct nfs_fsinfo *info)
{
        int error;
        struct nfs_fattr *fattr = info->fattr;

        error = nfs4_server_capabilities(server, mntfh);
        if (error < 0) {
                dprintk("nfs4_get_root: getcaps error = %d\n", -error);
                return error;
        }

        error = nfs4_proc_getattr(server, mntfh, fattr);
        if (error < 0) {
                dprintk("nfs4_get_root: getattr error = %d\n", -error);
                return error;
        }

        if (fattr->valid & NFS_ATTR_FATTR_FSID &&
            !nfs_fsid_equal(&server->fsid, &fattr->fsid))
                memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));

        return error;
}

/*
 * 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 rpc_clnt *client, 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(client, 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;
        }
        /* Fixup attributes for the nfs_lookup() call to nfs_fhget() */
        nfs_fixup_referral_attributes(&locations->fattr);

        /* replace the lookup nfs_fattr with the locations nfs_fattr */
        memcpy(fattr, &locations->fattr, sizeof(struct nfs_fattr));
        memset(fhandle, 0, sizeof(struct nfs_fh));
out:
        if (page)
                __free_page(page);
        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->client, server, &msg, &args.seq_args, &res.seq_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;

        if (pnfs_ld_layoutret_on_setattr(inode))
                pnfs_commit_and_return_layout(inode);

        nfs_fattr_init(fattr);
        
        /* Deal with open(O_TRUNC) */
        if (sattr->ia_valid & ATTR_OPEN)
                sattr->ia_valid &= ~(ATTR_MTIME|ATTR_CTIME|ATTR_OPEN);

        /* Optimization: if the end result is no change, don't RPC */
        if ((sattr->ia_valid & ~(ATTR_FILE)) == 0)
                return 0;

        /* 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_lookup(struct rpc_clnt *clnt, struct inode *dir,
                const struct qstr *name, struct nfs_fh *fhandle,
                struct nfs_fattr *fattr)
{
        struct nfs_server *server = NFS_SERVER(dir);
        int                    status;
        struct nfs4_lookup_arg args = {
                .bitmask = server->attr_bitmask,
                .dir_fh = NFS_FH(dir),
                .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  lookup %s\n", name->name);
        status = nfs4_call_sync(clnt, server, &msg, &args.seq_args, &res.seq_res, 0);
        dprintk("NFS reply lookup: %d\n", status);
        return status;
}

static void nfs_fixup_secinfo_attributes(struct nfs_fattr *fattr)
{
        fattr->valid |= NFS_ATTR_FATTR_TYPE | NFS_ATTR_FATTR_MODE |
                NFS_ATTR_FATTR_NLINK | NFS_ATTR_FATTR_MOUNTPOINT;
        fattr->mode = S_IFDIR | S_IRUGO | S_IXUGO;
        fattr->nlink = 2;
}

static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
                                   struct qstr *name, struct nfs_fh *fhandle,
                                   struct nfs_fattr *fattr)
{
        struct nfs4_exception exception = { };
        struct rpc_clnt *client = *clnt;
        int err;
        do {
                err = _nfs4_proc_lookup(client, dir, name, fhandle, fattr);
                switch (err) {
                case -NFS4ERR_BADNAME:
                        err = -ENOENT;
                        goto out;
                case -NFS4ERR_MOVED:
                        err = nfs4_get_referral(client, dir, name, fattr, fhandle);
                        goto out;
                case -NFS4ERR_WRONGSEC:
                        err = -EPERM;
                        if (client != *clnt)
                                goto out;

                        client = nfs4_create_sec_client(client, dir, name);
                        if (IS_ERR(client))
                                return PTR_ERR(client);

                        exception.retry = 1;
                        break;
                default:
                        err = nfs4_handle_exception(NFS_SERVER(dir), err, &exception);
                }
        } while (exception.retry);

out:
        if (err == 0)
                *clnt = client;
        else if (client != *clnt)
                rpc_shutdown_client(client);

        return err;
}

static int nfs4_proc_lookup(struct inode *dir, struct qstr *name,
                            struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
        int status;
        struct rpc_clnt *client = NFS_CLIENT(dir);

        status = nfs4_proc_lookup_common(&client, dir, name, fhandle, fattr);
        if (client != NFS_CLIENT(dir)) {
                rpc_shutdown_client(client);
                nfs_fixup_secinfo_attributes(fattr);
        }
        return status;
}

struct rpc_clnt *
nfs4_proc_lookup_mountpoint(struct inode *dir, struct qstr *name,
                            struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
        int status;
        struct rpc_clnt *client = rpc_clone_client(NFS_CLIENT(dir));

        status = nfs4_proc_lookup_common(&client, dir, name, fhandle, fattr);
        if (status < 0) {
                rpc_shutdown_client(client);
                return ERR_PTR(status);
        }
        return client;
}

static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_accessargs args = {
                .fh = NFS_FH(inode),
                .bitmask = server->cache_consistency_bitmask,
        };
        struct nfs4_accessres res = {
                .server = server,
        };
        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;
        }

        res.fattr = nfs_alloc_fattr();
        if (res.fattr == NULL)
                return -ENOMEM;

        status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
        if (!status) {
                nfs_access_set_mask(entry, res.access);
                nfs_refresh_inode(inode, res.fattr);
        }
        nfs_free_fattr(res.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.
 *
 * 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)->client, NFS_SERVER(inode), &msg, &args.seq_args, &res.seq_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;
}

/*
 * This is just for mknod.  open(O_CREAT) will always do ->open_context().
 */
static int
nfs4_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
                 int flags)
{
        struct nfs_open_context *ctx;
        struct nfs4_state *state;
        int status = 0;

        ctx = alloc_nfs_open_context(dentry, FMODE_READ);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);

        sattr->ia_mode &= ~current_umask();
        state = nfs4_do_open(dir, dentry, ctx->mode,
                        flags, sattr, ctx->cred,
                        &ctx->mdsthreshold);
        d_drop(dentry);
        if (IS_ERR(state)) {
                status = PTR_ERR(state);
                goto out;
        }
        d_add(dentry, igrab(state->inode));
        nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
        ctx->state = state;
out:
        put_nfs_open_context(ctx);
        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 = *name,
        };
        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;

        status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 1);
        if (status == 0)
                update_changeattr(dir, &res.cinfo);
        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;

        res->server = server;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_REMOVE];
        nfs41_init_sequence(&args->seq_args, &res->seq_res, 1);
}

static void nfs4_proc_unlink_rpc_prepare(struct rpc_task *task, struct nfs_unlinkdata *data)
{
        nfs4_setup_sequence(NFS_SERVER(data->dir),
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

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

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

static void nfs4_proc_rename_setup(struct rpc_message *msg, struct inode *dir)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_renameargs *arg = msg->rpc_argp;
        struct nfs_renameres *res = msg->rpc_resp;

        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RENAME];
        res->server = server;
        nfs41_init_sequence(&arg->seq_args, &res->seq_res, 1);
}

static void nfs4_proc_rename_rpc_prepare(struct rpc_task *task, struct nfs_renamedata *data)
{
        nfs4_setup_sequence(NFS_SERVER(data->old_dir),
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static int nfs4_proc_rename_done(struct rpc_task *task, struct inode *old_dir,
                                 struct inode *new_dir)
{
        struct nfs_renameres *res = task->tk_msg.rpc_resp;

        if (!nfs4_sequence_done(task, &res->seq_res))
                return 0;
        if (nfs4_async_handle_error(task, res->server, NULL) == -EAGAIN)
                return 0;

        update_changeattr(old_dir, &res->old_cinfo);
        update_changeattr(new_dir, &res->new_cinfo);
        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 nfs_renameargs arg = {
                .old_dir = NFS_FH(old_dir),
                .new_dir = NFS_FH(new_dir),
                .old_name = old_name,
                .new_name = new_name,
        };
        struct nfs_renameres res = {
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RENAME],
                .rpc_argp = &arg,
                .rpc_resp = &res,
        };
        int status = -ENOMEM;
        
        status = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_res, 1);
        if (!status) {
                update_changeattr(old_dir, &res.old_cinfo);
                update_changeattr(new_dir, &res.new_cinfo);
        }
        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 nfs4_link_res res = {
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LINK],
                .rpc_argp = &arg,
                .rpc_resp = &res,
        };
        int status = -ENOMEM;

        res.fattr = nfs_alloc_fattr();
        if (res.fattr == NULL)
                goto out;

        status = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_res, 1);
        if (!status) {
                update_changeattr(dir, &res.cinfo);
                nfs_post_op_update_inode(inode, res.fattr);
        }
out:
        nfs_free_fattr(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;
};

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;
                nfs_fattr_init(data->res.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)->client, NFS_SERVER(dir), &data->msg,
                                    &data->arg.seq_args, &data->res.seq_res, 1);
        if (status == 0) {
                update_changeattr(dir, &data->res.dir_cinfo);
                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;

        sattr->ia_mode &= ~current_umask();
        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 **pages, unsigned int count, int plus)
{
        struct inode            *dir = dentry->d_inode;
        struct nfs4_readdir_arg args = {
                .fh = NFS_FH(dir),
                .pages = pages,
                .pgbase = 0,
                .count = count,
                .bitmask = NFS_SERVER(dentry->d_inode)->attr_bitmask,
                .plus = plus,
        };
        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_I(dir)->cookieverf, dentry, &args);
        res.pgbase = args.pgbase;
        status = nfs4_call_sync(NFS_SERVER(dir)->client, NFS_SERVER(dir), &msg, &args.seq_args, &res.seq_res, 0);
        if (status >= 0) {
                memcpy(NFS_I(dir)->cookieverf, res.verifier.data, NFS4_VERIFIER_SIZE);
                status += args.pgbase;
        }

        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 **pages, 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,
                                        pages, 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;

        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);
        } else if (!S_ISSOCK(mode)) {
                status = -EINVAL;
                goto out_free;
        }
        
        status = nfs4_do_create(dir, dentry, data);
out_free:
        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;

        sattr->ia_mode &= ~current_umask();
        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->client, server, &msg, &args.seq_args, &res.seq_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->client, server, &msg, &args.seq_args, &res.seq_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)
{
        int error;

        nfs_fattr_init(fsinfo->fattr);
        error = nfs4_do_fsinfo(server, fhandle, fsinfo);
        if (error == 0) {
                /* block layout checks this! */
                server->pnfs_blksize = fsinfo->blksize;
                set_pnfs_layoutdriver(server, fhandle, fsinfo->layouttype);
        }

        return error;
}

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->client, server, &msg, &args.seq_args, &res.seq_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;
}

void __nfs4_read_done_cb(struct nfs_read_data *data)
{
        nfs_invalidate_atime(data->header->inode);
}

static int nfs4_read_done_cb(struct rpc_task *task, struct nfs_read_data *data)
{
        struct nfs_server *server = NFS_SERVER(data->header->inode);

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

        __nfs4_read_done_cb(data);
        if (task->tk_status > 0)
                renew_lease(server, data->timestamp);
        return 0;
}

static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
{

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

        if (!nfs4_sequence_done(task, &data->res.seq_res))
                return -EAGAIN;

        return data->read_done_cb ? data->read_done_cb(task, data) :
                                    nfs4_read_done_cb(task, data);
}

static void nfs4_proc_read_setup(struct nfs_read_data *data, struct rpc_message *msg)
{
        data->timestamp   = jiffies;
        data->read_done_cb = nfs4_read_done_cb;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ];
        nfs41_init_sequence(&data->args.seq_args, &data->res.seq_res, 0);
}

static void nfs4_proc_read_rpc_prepare(struct rpc_task *task, struct nfs_read_data *data)
{
        nfs4_setup_sequence(NFS_SERVER(data->header->inode),
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static int nfs4_write_done_cb(struct rpc_task *task, struct nfs_write_data *data)
{
        struct inode *inode = data->header->inode;
        
        if (nfs4_async_handle_error(task, NFS_SERVER(inode), data->args.context->state) == -EAGAIN) {
                rpc_restart_call_prepare(task);
                return -EAGAIN;
        }
        if (task->tk_status >= 0) {
                renew_lease(NFS_SERVER(inode), data->timestamp);
                nfs_post_op_update_inode_force_wcc(inode, &data->fattr);
        }
        return 0;
}

static int nfs4_write_done(struct rpc_task *task, struct nfs_write_data *data)
{
        if (!nfs4_sequence_done(task, &data->res.seq_res))
                return -EAGAIN;
        return data->write_done_cb ? data->write_done_cb(task, data) :
                nfs4_write_done_cb(task, data);
}

static
bool nfs4_write_need_cache_consistency_data(const struct nfs_write_data *data)
{
        const struct nfs_pgio_header *hdr = data->header;

        /* Don't request attributes for pNFS or O_DIRECT writes */
        if (data->ds_clp != NULL || hdr->dreq != NULL)
                return false;
        /* Otherwise, request attributes if and only if we don't hold
         * a delegation
         */
        return nfs4_have_delegation(hdr->inode, FMODE_READ) == 0;
}

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

        if (!nfs4_write_need_cache_consistency_data(data)) {
                data->args.bitmask = NULL;
                data->res.fattr = NULL;
        } else
                data->args.bitmask = server->cache_consistency_bitmask;

        if (!data->write_done_cb)
                data->write_done_cb = nfs4_write_done_cb;
        data->res.server = server;
        data->timestamp   = jiffies;

        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_WRITE];
        nfs41_init_sequence(&data->args.seq_args, &data->res.seq_res, 1);
}

static void nfs4_proc_write_rpc_prepare(struct rpc_task *task, struct nfs_write_data *data)
{
        nfs4_setup_sequence(NFS_SERVER(data->header->inode),
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static void nfs4_proc_commit_rpc_prepare(struct rpc_task *task, struct nfs_commit_data *data)
{
        nfs4_setup_sequence(NFS_SERVER(data->inode),
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static int nfs4_commit_done_cb(struct rpc_task *task, struct nfs_commit_data *data)
{
        struct inode *inode = data->inode;

        if (nfs4_async_handle_error(task, NFS_SERVER(inode), NULL) == -EAGAIN) {
                rpc_restart_call_prepare(task);
                return -EAGAIN;
        }
        return 0;
}

static int nfs4_commit_done(struct rpc_task *task, struct nfs_commit_data *data)
{
        if (!nfs4_sequence_done(task, &data->res.seq_res))
                return -EAGAIN;
        return data->commit_done_cb(task, data);
}

static void nfs4_proc_commit_setup(struct nfs_commit_data *data, struct rpc_message *msg)
{
        struct nfs_server *server = NFS_SERVER(data->inode);

        if (data->commit_done_cb == NULL)
                data->commit_done_cb = nfs4_commit_done_cb;
        data->res.server = server;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_COMMIT];
        nfs41_init_sequence(&data->args.seq_args, &data->res.seq_res, 1);
}

struct nfs4_renewdata {
        struct nfs_client       *client;
        unsigned long           timestamp;
};

/*
 * 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_release(void *calldata)
{
        struct nfs4_renewdata *data = calldata;
        struct nfs_client *clp = data->client;

        if (atomic_read(&clp->cl_count) > 1)
                nfs4_schedule_state_renewal(clp);
        nfs_put_client(clp);
        kfree(data);
}

static void nfs4_renew_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_renewdata *data = calldata;
        struct nfs_client *clp = data->client;
        unsigned long timestamp = data->timestamp;

        if (task->tk_status < 0) {
                /* Unless we're shutting down, schedule state recovery! */
                if (test_bit(NFS_CS_RENEWD, &clp->cl_res_state) == 0)
                        return;
                if (task->tk_status != NFS4ERR_CB_PATH_DOWN) {
                        nfs4_schedule_lease_recovery(clp);
                        return;
                }
                nfs4_schedule_path_down_recovery(clp);
        }
        do_renew_lease(clp, timestamp);
}

static const struct rpc_call_ops nfs4_renew_ops = {
        .rpc_call_done = nfs4_renew_done,
        .rpc_release = nfs4_renew_release,
};

static int nfs4_proc_async_renew(struct nfs_client *clp, struct rpc_cred *cred, unsigned renew_flags)
{
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_RENEW],
                .rpc_argp       = clp,
                .rpc_cred       = cred,
        };
        struct nfs4_renewdata *data;

        if (renew_flags == 0)
                return 0;
        if (!atomic_inc_not_zero(&clp->cl_count))
                return -EIO;
        data = kmalloc(sizeof(*data), GFP_NOFS);
        if (data == NULL)
                return -ENOMEM;
        data->client = clp;
        data->timestamp = jiffies;
        return rpc_call_async(clp->cl_rpcclient, &msg, RPC_TASK_SOFT,
                        &nfs4_renew_ops, data);
}

static 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;
        do_renew_lease(clp, now);
        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_SIZE, and that
 * it's OK to put sizeof(void) * (XATTR_SIZE_MAX/PAGE_SIZE) bytes on
 * the stack.
 */
#define NFS4ACL_MAXPAGES DIV_ROUND_UP(XATTR_SIZE_MAX, PAGE_SIZE)

static int buf_to_pages_noslab(const void *buf, size_t buflen,
                struct page **pages, unsigned int *pgbase)
{
        struct page *newpage, **spages;
        int rc = 0;
        size_t len;
        spages = pages;

        do {
                len = min_t(size_t, PAGE_SIZE, buflen);
                newpage = alloc_page(GFP_KERNEL);

                if (newpage == NULL)
                        goto unwind;
                memcpy(page_address(newpage), buf, len);
                buf += len;
                buflen -= len;
                *pages++ = newpage;
                rc++;
        } while (buflen != 0);

        return rc;

unwind:
        for(; rc > 0; rc--)
                __free_page(spages[rc-1]);
        return -ENOMEM;
}

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, struct page **pages, size_t pgbase, size_t acl_len)
{
        struct nfs4_cached_acl *acl;
        size_t buflen = sizeof(*acl) + acl_len;

        if (buflen <= PAGE_SIZE) {
                acl = kmalloc(buflen, GFP_KERNEL);
                if (acl == NULL)
                        goto out;
                acl->cached = 1;
                _copy_from_pages(acl->data, pages, pgbase, 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);
}

/*
 * The getxattr API returns the required buffer length when called with a
 * NULL buf. The NFSv4 acl tool then calls getxattr again after allocating
 * the required buf.  On a NULL buf, we send a page of data to the server
 * guessing that the ACL request can be serviced by a page. If so, we cache
 * up to the page of ACL data, and the 2nd call to getxattr is serviced by
 * the cache. If not so, we throw away the page, and cache the required
 * length. The next getxattr call will then produce another round trip to
 * the server, this time with the input buf of the required size.
 */
static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t buflen)
{
        struct page *pages[NFS4ACL_MAXPAGES] = {NULL, };
        struct nfs_getaclargs args = {
                .fh = NFS_FH(inode),
                .acl_pages = pages,
                .acl_len = buflen,
        };
        struct nfs_getaclres res = {
                .acl_len = buflen,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETACL],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE);
        int ret = -ENOMEM, i;

        /* As long as we're doing a round trip to the server anyway,
         * let's be prepared for a page of acl data. */
        if (npages == 0)
                npages = 1;
        if (npages > ARRAY_SIZE(pages))
                return -ERANGE;

        for (i = 0; i < npages; i++) {
                pages[i] = alloc_page(GFP_KERNEL);
                if (!pages[i])
                        goto out_free;
        }

        /* for decoding across pages */
        res.acl_scratch = alloc_page(GFP_KERNEL);
        if (!res.acl_scratch)
                goto out_free;

        args.acl_len = npages * PAGE_SIZE;
        args.acl_pgbase = 0;

        dprintk("%s  buf %p buflen %zu npages %d args.acl_len %zu\n",
                __func__, buf, buflen, npages, args.acl_len);
        ret = nfs4_call_sync(NFS_SERVER(inode)->client, NFS_SERVER(inode),
                             &msg, &args.seq_args, &res.seq_res, 0);
        if (ret)
                goto out_free;

        /* Handle the case where the passed-in buffer is too short */
        if (res.acl_flags & NFS4_ACL_TRUNC) {
                /* Did the user only issue a request for the acl length? */
                if (buf == NULL)
                        goto out_ok;
                ret = -ERANGE;
                goto out_free;
        }
        nfs4_write_cached_acl(inode, pages, res.acl_data_offset, res.acl_len);
        if (buf) {
                if (res.acl_len > buflen) {
                        ret = -ERANGE;
                        goto out_free;
                }
                _copy_from_pages(buf, pages, res.acl_data_offset, res.acl_len);
        }
out_ok:
        ret = res.acl_len;
out_free:
        for (i = 0; i < npages; i++)
                if (pages[i])
                        __free_page(pages[i]);
        if (res.acl_scratch)
                __free_page(res.acl_scratch);
        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)
                /* -ENOENT is returned if there is no ACL or if there is an ACL
                 * but no cached acl data, just the acl length */
                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,
        };
        unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE);
        int ret, i;

        if (!nfs4_server_supports_acls(server))
                return -EOPNOTSUPP;
        if (npages > ARRAY_SIZE(pages))
                return -ERANGE;
        i = buf_to_pages_noslab(buf, buflen, arg.acl_pages, &arg.acl_pgbase);
        if (i < 0)
                return i;
        nfs4_inode_return_delegation(inode);
        ret = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_res, 1);

        /*
         * Free each page after tx, so the only ref left is
         * held by the network stack
         */
        for (; i > 0; i--)
                put_page(pages[i-1]);

        /*
         * Acl update can result in inode attribute update.
         * so mark the attribute cache invalid.
         */
        spin_lock(&inode->i_lock);
        NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATTR;
        spin_unlock(&inode->i_lock);
        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 nfs4_state *state)
{
        struct nfs_client *clp = server->nfs_client;

        if (task->tk_status >= 0)
                return 0;
        switch(task->tk_status) {
                case -NFS4ERR_DELEG_REVOKED:
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_BAD_STATEID:
                        if (state == NULL)
                                break;
                        nfs_remove_bad_delegation(state->inode);
                case -NFS4ERR_OPENMODE:
                        if (state == NULL)
                                break;
                        nfs4_schedule_stateid_recovery(server, state);
                        goto wait_on_recovery;
                case -NFS4ERR_EXPIRED:
                        if (state != NULL)
                                nfs4_schedule_stateid_recovery(server, state);
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_STALE_CLIENTID:
                        nfs4_schedule_lease_recovery(clp);
                        goto wait_on_recovery;
#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);
                        nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
                        task->tk_status = 0;
                        return -EAGAIN;
#endif /* CONFIG_NFS_V4_1 */
                case -NFS4ERR_DELAY:
                        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_RETRY_UNCACHED_REP:
                case -NFS4ERR_OLD_STATEID:
                        task->tk_status = 0;
                        return -EAGAIN;
        }
        task->tk_status = nfs4_map_errors(task->tk_status);
        return 0;
wait_on_recovery:
        rpc_sleep_on(&clp->cl_rpcwaitq, task, NULL);
        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;
}

static void nfs4_init_boot_verifier(const struct nfs_client *clp,
                                    nfs4_verifier *bootverf)
{
        __be32 verf[2];

        if (test_bit(NFS4CLNT_PURGE_STATE, &clp->cl_state)) {
                /* An impossible timestamp guarantees this value
                 * will never match a generated boot time. */
                verf[0] = 0;
                verf[1] = (__be32)(NSEC_PER_SEC + 1);
        } else {
                struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
                verf[0] = (__be32)nn->boot_time.tv_sec;
                verf[1] = (__be32)nn->boot_time.tv_nsec;
        }
        memcpy(bootverf->data, verf, sizeof(bootverf->data));
}

static unsigned int
nfs4_init_nonuniform_client_string(const struct nfs_client *clp,
                                   char *buf, size_t len)
{
        unsigned int result;

        rcu_read_lock();
        result = scnprintf(buf, len, "Linux NFSv4.0 %s/%s %s",
                                clp->cl_ipaddr,
                                rpc_peeraddr2str(clp->cl_rpcclient,
                                                        RPC_DISPLAY_ADDR),
                                rpc_peeraddr2str(clp->cl_rpcclient,
                                                        RPC_DISPLAY_PROTO));
        rcu_read_unlock();
        return result;
}

static unsigned int
nfs4_init_uniform_client_string(const struct nfs_client *clp,
                                char *buf, size_t len)
{
        char *nodename = clp->cl_rpcclient->cl_nodename;

        if (nfs4_client_id_uniquifier[0] != '\0')
                nodename = nfs4_client_id_uniquifier;
        return scnprintf(buf, len, "Linux NFSv%u.%u %s",
                                clp->rpc_ops->version, clp->cl_minorversion,
                                nodename);
}

/**
 * nfs4_proc_setclientid - Negotiate client ID
 * @clp: state data structure
 * @program: RPC program for NFSv4 callback service
 * @port: IP port number for NFS4 callback service
 * @cred: RPC credential to use for this call
 * @res: where to place the result
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status code.
 */
int nfs4_proc_setclientid(struct nfs_client *clp, u32 program,
                unsigned short port, struct rpc_cred *cred,
                struct nfs4_setclientid_res *res)
{
        nfs4_verifier sc_verifier;
        struct nfs4_setclientid setclientid = {
                .sc_verifier = &sc_verifier,
                .sc_prog = program,
                .sc_cb_ident = clp->cl_cb_ident,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SETCLIENTID],
                .rpc_argp = &setclientid,
                .rpc_resp = res,
                .rpc_cred = cred,
        };
        int status;

        /* nfs_client_id4 */
        nfs4_init_boot_verifier(clp, &sc_verifier);
        if (test_bit(NFS_CS_MIGRATION, &clp->cl_flags))
                setclientid.sc_name_len =
                                nfs4_init_uniform_client_string(clp,
                                                setclientid.sc_name,
                                                sizeof(setclientid.sc_name));
        else
                setclientid.sc_name_len =
                                nfs4_init_nonuniform_client_string(clp,
                                                setclientid.sc_name,
                                                sizeof(setclientid.sc_name));
        /* cb_client4 */
        rcu_read_lock();
        setclientid.sc_netid_len = scnprintf(setclientid.sc_netid,
                                sizeof(setclientid.sc_netid),
                                rpc_peeraddr2str(clp->cl_rpcclient,
                                                        RPC_DISPLAY_NETID));
        rcu_read_unlock();
        setclientid.sc_uaddr_len = scnprintf(setclientid.sc_uaddr,
                                sizeof(setclientid.sc_uaddr), "%s.%u.%u",
                                clp->cl_ipaddr, port >> 8, port & 255);

        dprintk("NFS call  setclientid auth=%s, '%.*s'\n",
                clp->cl_rpcclient->cl_auth->au_ops->au_name,
                setclientid.sc_name_len, setclientid.sc_name);
        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        dprintk("NFS reply setclientid: %d\n", status);
        return status;
}

/**
 * nfs4_proc_setclientid_confirm - Confirm client ID
 * @clp: state data structure
 * @res: result of a previous SETCLIENTID
 * @cred: RPC credential to use for this call
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status code.
 */
int nfs4_proc_setclientid_confirm(struct nfs_client *clp,
                struct nfs4_setclientid_res *arg,
                struct rpc_cred *cred)
{
        struct nfs_fsinfo fsinfo;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SETCLIENTID_CONFIRM],
                .rpc_argp = arg,
                .rpc_resp = &fsinfo,
                .rpc_cred = cred,
        };
        unsigned long now;
        int status;

        dprintk("NFS call  setclientid_confirm auth=%s, (client ID %llx)\n",
                clp->cl_rpcclient->cl_auth->au_ops->au_name,
                clp->cl_clientid);
        now = jiffies;
        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        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);
        }
        dprintk("NFS reply setclientid_confirm: %d\n", status);
        return status;
}

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;

        if (!nfs4_sequence_done(task, &data->res.seq_res))
                return;

        switch (task->tk_status) {
        case -NFS4ERR_STALE_STATEID:
        case -NFS4ERR_EXPIRED:
        case 0:
                renew_lease(data->res.server, data->timestamp);
                break;
        default:
                if (nfs4_async_handle_error(task, data->res.server, NULL) ==
                                -EAGAIN) {
                        rpc_restart_call_prepare(task);
                        return;
                }
        }
        data->rpc_status = task->tk_status;
}

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;

        nfs4_setup_sequence(d_data->res.server,
                        &d_data->args.seq_args,
                        &d_data->res.seq_res,
                        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_NOFS);
        if (data == NULL)
                return -ENOMEM;
        nfs41_init_sequence(&data->args.seq_args, &data->res.seq_res, 1);
        data->args.fhandle = &data->fh;
        data->args.stateid = &data->stateid;
        data->args.bitmask = server->cache_consistency_bitmask;
        nfs_copy_fh(&data->fh, NFS_FH(inode));
        nfs4_stateid_copy(&data->stateid, stateid);
        data->res.fattr = &data->fattr;
        data->res.server = server;
        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)
                nfs_post_op_update_inode_force_wcc(inode, &data->fattr);
        else
                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)
{
        freezable_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_seqid.owner_id;
        arg.lock_owner.s_dev = server->s_dev;
        status = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_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_NOFS);
        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->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;

        if (!nfs4_sequence_done(task, &calldata->res.seq_res))
                return;
        switch (task->tk_status) {
                case 0:
                        nfs4_stateid_copy(&calldata->lsp->ls_stateid,
                                        &calldata->res.stateid);
                        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)
                                rpc_restart_call_prepare(task);
        }
        nfs_release_seqid(calldata->arg.seqid);
}

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)
                goto out_wait;
        if (test_bit(NFS_LOCK_INITIALIZED, &calldata->lsp->ls_flags) == 0) {
                /* Note: exit _without_ running nfs4_locku_done */
                goto out_no_action;
        }
        calldata->timestamp = jiffies;
        if (nfs4_setup_sequence(calldata->server,
                                &calldata->arg.seq_args,
                                &calldata->res.seq_res,
                                task) != 0)
                nfs_release_seqid(calldata->arg.seqid);
        return;
out_no_action:
        task->tk_action = NULL;
out_wait:
        nfs4_sequence_done(task, &calldata->res.seq_res);
}

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);
        }

        nfs41_init_sequence(&data->arg.seq_args, &data->res.seq_res, 1);
        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 inode *inode = state->inode;
        struct nfs4_state_owner *sp = state->owner;
        struct nfs_inode *nfsi = NFS_I(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;
        /* Exclude nfs_delegation_claim_locks() */
        mutex_lock(&sp->so_delegreturn_mutex);
        /* Exclude nfs4_reclaim_open_stateid() - note nesting! */
        down_read(&nfsi->rwsem);
        if (do_vfs_lock(request->fl_file, request) == -ENOENT) {
                up_read(&nfsi->rwsem);
                mutex_unlock(&sp->so_delegreturn_mutex);
                goto out;
        }
        up_read(&nfsi->rwsem);
        mutex_unlock(&sp->so_delegreturn_mutex);
        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, GFP_KERNEL);
        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,
                gfp_t gfp_mask)
{
        struct nfs4_lockdata *p;
        struct inode *inode = lsp->ls_state->inode;
        struct nfs_server *server = NFS_SERVER(inode);

        p = kzalloc(sizeof(*p), gfp_mask);
        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, gfp_mask);
        if (p->arg.open_seqid == NULL)
                goto out_free;
        p->arg.lock_seqid = nfs_alloc_seqid(&lsp->ls_seqid, gfp_mask);
        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_seqid.owner_id;
        p->arg.lock_owner.s_dev = server->s_dev;
        p->res.lock_seqid = p->arg.lock_seqid;
        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)
                goto out_wait;
        /* 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) {
                        goto out_release_lock_seqid;
                }
                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,
                                &data->arg.seq_args,
                                &data->res.seq_res,
                                task) == 0)
                return;
        nfs_release_seqid(data->arg.open_seqid);
out_release_lock_seqid:
        nfs_release_seqid(data->arg.lock_seqid);
out_wait:
        nfs4_sequence_done(task, &data->res.seq_res);
        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__);

        if (!nfs4_sequence_done(task, &data->res.seq_res))
                return;

        data->rpc_status = task->tk_status;
        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) {
                nfs4_stateid_copy(&data->lsp->ls_stateid, &data->res.stateid);
                set_bit(NFS_LOCK_INITIALIZED, &data->lsp->ls_flags);
                renew_lease(NFS_SERVER(data->ctx->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_async(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 void nfs4_handle_setlk_error(struct nfs_server *server, struct nfs4_lock_state *lsp, int new_lock_owner, int error)
{
        switch (error) {
        case -NFS4ERR_ADMIN_REVOKED:
        case -NFS4ERR_BAD_STATEID:
                lsp->ls_seqid.flags &= ~NFS_SEQID_CONFIRMED;
                if (new_lock_owner != 0 ||
                   test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags) != 0)
                        nfs4_schedule_stateid_recovery(server, lsp->ls_state);
                break;
        case -NFS4ERR_STALE_STATEID:
                lsp->ls_seqid.flags &= ~NFS_SEQID_CONFIRMED;
        case -NFS4ERR_EXPIRED:
                nfs4_schedule_lease_recovery(server->nfs_client);
        };
}

static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *fl, int recovery_type)
{
        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,
                        recovery_type == NFS_LOCK_NEW ? GFP_KERNEL : GFP_NOFS);
        if (data == NULL)
                return -ENOMEM;
        if (IS_SETLKW(cmd))
                data->arg.block = 1;
        nfs41_init_sequence(&data->arg.seq_args, &data->res.seq_res, 1);
        msg.rpc_argp = &data->arg;
        msg.rpc_resp = &data->res;
        task_setup_data.callback_data = data;
        if (recovery_type > NFS_LOCK_NEW) {
                if (recovery_type == NFS_LOCK_RECLAIM)
                        data->arg.reclaim = NFS_LOCK_RECLAIM;
                nfs4_set_sequence_privileged(&data->arg.seq_args);
        }
        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)
                        nfs4_handle_setlk_error(data->server, data->lsp,
                                        data->arg.new_lock_owner, ret);
        } 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 = {
                .inode = state->inode,
        };
        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, NFS_LOCK_RECLAIM);
                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 = {
                .inode = state->inode,
        };
        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, NFS_LOCK_EXPIRED);
                switch (err) {
                default:
                        goto out;
                case -NFS4ERR_GRACE:
                case -NFS4ERR_DELAY:
                        nfs4_handle_exception(server, err, &exception);
                        err = 0;
                }
        } while (exception.retry);
out:
        return err;
}

#if defined(CONFIG_NFS_V4_1)
/**
 * nfs41_check_expired_locks - possibly free a lock stateid
 *
 * @state: NFSv4 state for an inode
 *
 * Returns NFS_OK if recovery for this stateid is now finished.
 * Otherwise a negative NFS4ERR value is returned.
 */
static int nfs41_check_expired_locks(struct nfs4_state *state)
{
        int status, ret = -NFS4ERR_BAD_STATEID;
        struct nfs4_lock_state *lsp;
        struct nfs_server *server = NFS_SERVER(state->inode);

        list_for_each_entry(lsp, &state->lock_states, ls_locks) {
                if (test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags)) {
                        status = nfs41_test_stateid(server, &lsp->ls_stateid);
                        if (status != NFS_OK) {
                                /* Free the stateid unless the server
                                 * informs us the stateid is unrecognized. */
                                if (status != -NFS4ERR_BAD_STATEID)
                                        nfs41_free_stateid(server,
                                                        &lsp->ls_stateid);
                                clear_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags);
                                ret = status;
                        }
                }
        };

        return ret;
}

static int nfs41_lock_expired(struct nfs4_state *state, struct file_lock *request)
{
        int status = NFS_OK;

        if (test_bit(LK_STATE_IN_USE, &state->flags))
                status = nfs41_check_expired_locks(state);
        if (status != NFS_OK)
                status = nfs4_lock_expired(state, request);
        return status;
}
#endif

static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs4_state_owner *sp = state->owner;
        struct nfs_inode *nfsi = NFS_I(state->inode);
        unsigned char fl_flags = request->fl_flags;
        unsigned int seq;
        int status = -ENOLCK;

        if ((fl_flags & FL_POSIX) &&
                        !test_bit(NFS_STATE_POSIX_LOCKS, &state->flags))
                goto out;
        /* 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;
        }
        seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
        up_read(&nfsi->rwsem);
        status = _nfs4_do_setlk(state, cmd, request, NFS_LOCK_NEW);
        if (status != 0)
                goto out;
        down_read(&nfsi->rwsem);
        if (read_seqcount_retry(&sp->so_reclaim_seqcount, seq)) {
                status = -NFS4ERR_DELAY;
                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 "NFS: %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 = {
                .state = state,
                .inode = state->inode,
        };
        int err;

        do {
                err = _nfs4_proc_setlk(state, cmd, request);
                if (err == -NFS4ERR_DENIED)
                        err = -EAGAIN;
                err = nfs4_handle_exception(NFS_SERVER(state->inode),
                                err, &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)) {
                if (state != NULL)
                        return nfs4_proc_getlk(state, F_GETLK, request);
                return 0;
        }

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

        if (request->fl_type == F_UNLCK) {
                if (state != NULL)
                        return nfs4_proc_unlck(state, cmd, request);
                return 0;
        }

        if (state == NULL)
                return -ENOLCK;
        /*
         * Don't rely on the VFS having checked the file open mode,
         * since it won't do this for flock() locks.
         */
        switch (request->fl_type) {
        case F_RDLCK:
                if (!(filp->f_mode & FMODE_READ))
                        return -EBADF;
                break;
        case F_WRLCK:
                if (!(filp->f_mode & FMODE_WRITE))
                        return -EBADF;
        }

        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, NFS_LOCK_NEW);
                switch (err) {
                        default:
                                printk(KERN_ERR "NFS: %s: unhandled error "
                                        "%d.\n", __func__, err);
                        case 0:
                        case -ESTALE:
                                goto out;
                        case -NFS4ERR_STALE_CLIENTID:
                        case -NFS4ERR_STALE_STATEID:
                                set_bit(NFS_DELEGATED_STATE, &state->flags);
                        case -NFS4ERR_EXPIRED:
                                nfs4_schedule_lease_recovery(server->nfs_client);
                                err = -EAGAIN;
                                goto out;
                        case -NFS4ERR_BADSESSION:
                        case -NFS4ERR_BADSLOT:
                        case -NFS4ERR_BAD_HIGH_SLOT:
                        case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
                        case -NFS4ERR_DEADSESSION:
                                set_bit(NFS_DELEGATED_STATE, &state->flags);
                                nfs4_schedule_session_recovery(server->nfs_client->cl_session, err);
                                err = -EAGAIN;
                                goto out;
                        case -NFS4ERR_DELEG_REVOKED:
                        case -NFS4ERR_ADMIN_REVOKED:
                        case -NFS4ERR_BAD_STATEID:
                        case -NFS4ERR_OPENMODE:
                                nfs4_schedule_stateid_recovery(server, state);
                                err = 0;
                                goto out;
                        case -ENOMEM:
                        case -NFS4ERR_DENIED:
                                /* kill_proc(fl->fl_pid, SIGLOST, 1); */
                                err = 0;
                                goto out;
                }
                set_bit(NFS_DELEGATED_STATE, &state->flags);
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
out:
        return err;
}

struct nfs_release_lockowner_data {
        struct nfs4_lock_state *lsp;
        struct nfs_server *server;
        struct nfs_release_lockowner_args args;
};

static void nfs4_release_lockowner_release(void *calldata)
{
        struct nfs_release_lockowner_data *data = calldata;
        nfs4_free_lock_state(data->server, data->lsp);
        kfree(calldata);
}

static const struct rpc_call_ops nfs4_release_lockowner_ops = {
        .rpc_release = nfs4_release_lockowner_release,
};

int nfs4_release_lockowner(struct nfs4_lock_state *lsp)
{
        struct nfs_server *server = lsp->ls_state->owner->so_server;
        struct nfs_release_lockowner_data *data;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RELEASE_LOCKOWNER],
        };

        if (server->nfs_client->cl_mvops->minor_version != 0)
                return -EINVAL;
        data = kmalloc(sizeof(*data), GFP_NOFS);
        if (!data)
                return -ENOMEM;
        data->lsp = lsp;
        data->server = server;
        data->args.lock_owner.clientid = server->nfs_client->cl_clientid;
        data->args.lock_owner.id = lsp->ls_seqid.owner_id;
        data->args.lock_owner.s_dev = server->s_dev;
        msg.rpc_argp = &data->args;
        rpc_call_async(server->client, &msg, 0, &nfs4_release_lockowner_ops, data);
        return 0;
}

#define XATTR_NAME_NFSV4_ACL "system.nfs4_acl"

static int nfs4_xattr_set_nfs4_acl(struct dentry *dentry, const char *key,
                                   const void *buf, size_t buflen,
                                   int flags, int type)
{
        if (strcmp(key, "") != 0)
                return -EINVAL;

        return nfs4_proc_set_acl(dentry->d_inode, buf, buflen);
}

static int nfs4_xattr_get_nfs4_acl(struct dentry *dentry, const char *key,
                                   void *buf, size_t buflen, int type)
{
        if (strcmp(key, "") != 0)
                return -EINVAL;

        return nfs4_proc_get_acl(dentry->d_inode, buf, buflen);
}

static size_t nfs4_xattr_list_nfs4_acl(struct dentry *dentry, char *list,
                                       size_t list_len, const char *name,
                                       size_t name_len, int type)
{
        size_t len = sizeof(XATTR_NAME_NFSV4_ACL);

        if (!nfs4_server_supports_acls(NFS_SERVER(dentry->d_inode)))
                return 0;

        if (list && len <= list_len)
                memcpy(list, XATTR_NAME_NFSV4_ACL, len);
        return len;
}

/*
 * nfs_fhget will use either the mounted_on_fileid or the fileid
 */
static void nfs_fixup_referral_attributes(struct nfs_fattr *fattr)
{
        if (!(((fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID) ||
               (fattr->valid & NFS_ATTR_FATTR_FILEID)) &&
              (fattr->valid & NFS_ATTR_FATTR_FSID) &&
              (fattr->valid & NFS_ATTR_FATTR_V4_LOCATIONS)))
                return;

        fattr->valid |= NFS_ATTR_FATTR_TYPE | NFS_ATTR_FATTR_MODE |
                NFS_ATTR_FATTR_NLINK | NFS_ATTR_FATTR_V4_REFERRAL;
        fattr->mode = S_IFDIR | S_IRUGO | S_IXUGO;
        fattr->nlink = 2;
}

static int _nfs4_proc_fs_locations(struct rpc_clnt *client, 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,
        };
        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__);

        /* Ask for the fileid of the absent filesystem if mounted_on_fileid
         * is not supported */
        if (NFS_SERVER(dir)->attr_bitmask[1] & FATTR4_WORD1_MOUNTED_ON_FILEID)
                bitmask[1] |= FATTR4_WORD1_MOUNTED_ON_FILEID;
        else
                bitmask[0] |= FATTR4_WORD0_FILEID;

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

int nfs4_proc_fs_locations(struct rpc_clnt *client, struct inode *dir,
                           const struct qstr *name,
                           struct nfs4_fs_locations *fs_locations,
                           struct page *page)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dir),
                                _nfs4_proc_fs_locations(client, dir, name, fs_locations, page),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_secinfo(struct inode *dir, const struct qstr *name, struct nfs4_secinfo_flavors *flavors)
{
        int status;
        struct nfs4_secinfo_arg args = {
                .dir_fh = NFS_FH(dir),
                .name   = name,
        };
        struct nfs4_secinfo_res res = {
                .flavors     = flavors,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SECINFO],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        dprintk("NFS call  secinfo %s\n", name->name);
        status = nfs4_call_sync(NFS_SERVER(dir)->client, NFS_SERVER(dir), &msg, &args.seq_args, &res.seq_res, 0);
        dprintk("NFS reply  secinfo: %d\n", status);
        return status;
}

int nfs4_proc_secinfo(struct inode *dir, const struct qstr *name,
                      struct nfs4_secinfo_flavors *flavors)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dir),
                                _nfs4_proc_secinfo(dir, name, flavors),
                                &exception);
        } while (exception.retry);
        return err;
}

#ifdef CONFIG_NFS_V4_1
/*
 * Check the exchange flags returned by the server for invalid flags, having
 * both PNFS and NON_PNFS flags set, and not having one of NON_PNFS, PNFS, or
 * DS flags set.
 */
static int nfs4_check_cl_exchange_flags(u32 flags)
{
        if (flags & ~EXCHGID4_FLAG_MASK_R)
                goto out_inval;
        if ((flags & EXCHGID4_FLAG_USE_PNFS_MDS) &&
            (flags & EXCHGID4_FLAG_USE_NON_PNFS))
                goto out_inval;
        if (!(flags & (EXCHGID4_FLAG_MASK_PNFS)))
                goto out_inval;
        return NFS_OK;
out_inval:
        return -NFS4ERR_INVAL;
}

static bool
nfs41_same_server_scope(struct nfs41_server_scope *a,
                        struct nfs41_server_scope *b)
{
        if (a->server_scope_sz == b->server_scope_sz &&
            memcmp(a->server_scope, b->server_scope, a->server_scope_sz) == 0)
                return true;

        return false;
}

/*
 * nfs4_proc_bind_conn_to_session()
 *
 * The 4.1 client currently uses the same TCP connection for the
 * fore and backchannel.
 */
int nfs4_proc_bind_conn_to_session(struct nfs_client *clp, struct rpc_cred *cred)
{
        int status;
        struct nfs41_bind_conn_to_session_res res;
        struct rpc_message msg = {
                .rpc_proc =
                        &nfs4_procedures[NFSPROC4_CLNT_BIND_CONN_TO_SESSION],
                .rpc_argp = clp,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };

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

        res.session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
        if (unlikely(res.session == NULL)) {
                status = -ENOMEM;
                goto out;
        }

        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        if (status == 0) {
                if (memcmp(res.session->sess_id.data,
                    clp->cl_session->sess_id.data, NFS4_MAX_SESSIONID_LEN)) {
                        dprintk("NFS: %s: Session ID mismatch\n", __func__);
                        status = -EIO;
                        goto out_session;
                }
                if (res.dir != NFS4_CDFS4_BOTH) {
                        dprintk("NFS: %s: Unexpected direction from server\n",
                                __func__);
                        status = -EIO;
                        goto out_session;
                }
                if (res.use_conn_in_rdma_mode) {
                        dprintk("NFS: %s: Server returned RDMA mode = true\n",
                                __func__);
                        status = -EIO;
                        goto out_session;
                }
        }
out_session:
        kfree(res.session);
out:
        dprintk("<-- %s status= %d\n", __func__, status);
        return status;
}

/*
 * nfs4_proc_exchange_id()
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status code.
 *
 * 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.
 */
int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
{
        nfs4_verifier verifier;
        struct nfs41_exchange_id_args args = {
                .verifier = &verifier,
                .client = clp,
                .flags = EXCHGID4_FLAG_SUPP_MOVED_REFER,
        };
        struct nfs41_exchange_id_res res = {
                0
        };
        int status;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_EXCHANGE_ID],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };

        nfs4_init_boot_verifier(clp, &verifier);
        args.id_len = nfs4_init_uniform_client_string(clp, args.id,
                                                        sizeof(args.id));
        dprintk("NFS call  exchange_id auth=%s, '%.*s'\n",
                clp->cl_rpcclient->cl_auth->au_ops->au_name,
                args.id_len, args.id);

        res.server_owner = kzalloc(sizeof(struct nfs41_server_owner),
                                        GFP_NOFS);
        if (unlikely(res.server_owner == NULL)) {
                status = -ENOMEM;
                goto out;
        }

        res.server_scope = kzalloc(sizeof(struct nfs41_server_scope),
                                        GFP_NOFS);
        if (unlikely(res.server_scope == NULL)) {
                status = -ENOMEM;
                goto out_server_owner;
        }

        res.impl_id = kzalloc(sizeof(struct nfs41_impl_id), GFP_NOFS);
        if (unlikely(res.impl_id == NULL)) {
                status = -ENOMEM;
                goto out_server_scope;
        }

        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        if (status == 0)
                status = nfs4_check_cl_exchange_flags(res.flags);

        if (status == 0) {
                clp->cl_clientid = res.clientid;
                clp->cl_exchange_flags = (res.flags & ~EXCHGID4_FLAG_CONFIRMED_R);
                if (!(res.flags & EXCHGID4_FLAG_CONFIRMED_R))
                        clp->cl_seqid = res.seqid;

                kfree(clp->cl_serverowner);
                clp->cl_serverowner = res.server_owner;
                res.server_owner = NULL;

                /* use the most recent implementation id */
                kfree(clp->cl_implid);
                clp->cl_implid = res.impl_id;

                if (clp->cl_serverscope != NULL &&
                    !nfs41_same_server_scope(clp->cl_serverscope,
                                             res.server_scope)) {
                        dprintk("%s: server_scope mismatch detected\n",
                                __func__);
                        set_bit(NFS4CLNT_SERVER_SCOPE_MISMATCH, &clp->cl_state);
                        kfree(clp->cl_serverscope);
                        clp->cl_serverscope = NULL;
                }

                if (clp->cl_serverscope == NULL) {
                        clp->cl_serverscope = res.server_scope;
                        goto out;
                }
        } else
                kfree(res.impl_id);

out_server_owner:
        kfree(res.server_owner);
out_server_scope:
        kfree(res.server_scope);
out:
        if (clp->cl_implid != NULL)
                dprintk("NFS reply exchange_id: Server Implementation ID: "
                        "domain: %s, name: %s, date: %llu,%u\n",
                        clp->cl_implid->domain, clp->cl_implid->name,
                        clp->cl_implid->date.seconds,
                        clp->cl_implid->date.nseconds);
        dprintk("NFS reply exchange_id: %d\n", status);
        return status;
}

static int _nfs4_proc_destroy_clientid(struct nfs_client *clp,
                struct rpc_cred *cred)
{
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DESTROY_CLIENTID],
                .rpc_argp = clp,
                .rpc_cred = cred,
        };
        int status;

        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        if (status)
                dprintk("NFS: Got error %d from the server %s on "
                        "DESTROY_CLIENTID.", status, clp->cl_hostname);
        return status;
}

static int nfs4_proc_destroy_clientid(struct nfs_client *clp,
                struct rpc_cred *cred)
{
        unsigned int loop;
        int ret;

        for (loop = NFS4_MAX_LOOP_ON_RECOVER; loop != 0; loop--) {
                ret = _nfs4_proc_destroy_clientid(clp, cred);
                switch (ret) {
                case -NFS4ERR_DELAY:
                case -NFS4ERR_CLIENTID_BUSY:
                        ssleep(1);
                        break;
                default:
                        return ret;
                }
        }
        return 0;
}

int nfs4_destroy_clientid(struct nfs_client *clp)
{
        struct rpc_cred *cred;
        int ret = 0;

        if (clp->cl_mvops->minor_version < 1)
                goto out;
        if (clp->cl_exchange_flags == 0)
                goto out;
        if (clp->cl_preserve_clid)
                goto out;
        cred = nfs4_get_exchange_id_cred(clp);
        ret = nfs4_proc_destroy_clientid(clp, cred);
        if (cred)
                put_rpccred(cred);
        switch (ret) {
        case 0:
        case -NFS4ERR_STALE_CLIENTID:
                clp->cl_exchange_flags = 0;
        }
out:
        return ret;
}

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)
{
        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 */
        nfs41_setup_sequence(data->clp->cl_session,
                        &data->args->la_seq_args,
                        &data->res->lr_seq_res,
                        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__);
        if (!nfs41_sequence_done(task, &data->res->lr_seq_res))
                return;
        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;
                /* fall through */
        case -NFS4ERR_RETRY_UNCACHED_REP:
                rpc_restart_call_prepare(task);
                return;
        }
        dprintk("<-- %s\n", __func__);
}

static const 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,
                .flags = RPC_TASK_TIMEOUT,
        };
        int status;

        nfs41_init_sequence(&args.la_seq_args, &res.lr_seq_res, 0);
        nfs4_set_sequence_privileged(&args.la_seq_args);
        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;
}

/*
 * 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_target_max_rqst_sz,
                     mxresp_sz = session->fc_target_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.max_rqst_sz = mxrqst_sz;
        args->fc_attrs.max_resp_sz = mxresp_sz;
        args->fc_attrs.max_ops = NFS4_MAX_OPS;
        args->fc_attrs.max_reqs = max_session_slots;

        dprintk("%s: Fore Channel : max_rqst_sz=%u max_resp_sz=%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_ops, args->fc_attrs.max_reqs);

        /* Back channel attributes */
        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 nfs4_verify_fore_channel_attrs(struct nfs41_create_session_args *args, struct nfs4_session *session)
{
        struct nfs4_channel_attrs *sent = &args->fc_attrs;
        struct nfs4_channel_attrs *rcvd = &session->fc_attrs;

        if (rcvd->max_resp_sz > sent->max_resp_sz)
                return -EINVAL;
        /*
         * Our requested max_ops is the minimum we need; we're not
         * prepared to break up compounds into smaller pieces than that.
         * So, no point even trying to continue if the server won't
         * cooperate:
         */
        if (rcvd->max_ops < sent->max_ops)
                return -EINVAL;
        if (rcvd->max_reqs == 0)
                return -EINVAL;
        if (rcvd->max_reqs > NFS4_MAX_SLOT_TABLE)
                rcvd->max_reqs = NFS4_MAX_SLOT_TABLE;
        return 0;
}

static int nfs4_verify_back_channel_attrs(struct nfs41_create_session_args *args, struct nfs4_session *session)
{
        struct nfs4_channel_attrs *sent = &args->bc_attrs;
        struct nfs4_channel_attrs *rcvd = &session->bc_attrs;

        if (rcvd->max_rqst_sz > sent->max_rqst_sz)
                return -EINVAL;
        if (rcvd->max_resp_sz < sent->max_resp_sz)
                return -EINVAL;
        if (rcvd->max_resp_sz_cached > sent->max_resp_sz_cached)
                return -EINVAL;
        /* These would render the backchannel useless: */
        if (rcvd->max_ops != sent->max_ops)
                return -EINVAL;
        if (rcvd->max_reqs != sent->max_reqs)
                return -EINVAL;
        return 0;
}

static int nfs4_verify_channel_attrs(struct nfs41_create_session_args *args,
                                     struct nfs4_session *session)
{
        int ret;

        ret = nfs4_verify_fore_channel_attrs(args, session);
        if (ret)
                return ret;
        return nfs4_verify_back_channel_attrs(args, session);
}

static int _nfs4_proc_create_session(struct nfs_client *clp,
                struct rpc_cred *cred)
{
        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,
                .rpc_cred = cred,
        };
        int status;

        nfs4_init_channel_attrs(&args);
        args.flags = (SESSION4_PERSIST | SESSION4_BACK_CHAN);

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

        if (!status) {
                /* Verify the session's negotiated channel_attrs values */
                status = nfs4_verify_channel_attrs(&args, session);
                /* 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, struct rpc_cred *cred)
{
        int status;
        unsigned *ptr;
        struct nfs4_session *session = clp->cl_session;

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

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

        /* Init or reset the session slot tables */
        status = nfs4_setup_session_slot_tables(session);
        dprintk("slot table setup 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]);
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,
                struct rpc_cred *cred)
{
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DESTROY_SESSION],
                .rpc_argp = session,
                .rpc_cred = cred,
        };
        int status = 0;

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

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

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

        if (status)
                dprintk("NFS: 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.
 */
struct nfs4_sequence_data {
        struct nfs_client *clp;
        struct nfs4_sequence_args args;
        struct nfs4_sequence_res res;
};

static void nfs41_sequence_release(void *data)
{
        struct nfs4_sequence_data *calldata = data;
        struct nfs_client *clp = calldata->clp;

        if (atomic_read(&clp->cl_count) > 1)
                nfs4_schedule_state_renewal(clp);
        nfs_put_client(clp);
        kfree(calldata);
}

static int nfs41_sequence_handle_errors(struct rpc_task *task, struct nfs_client *clp)
{
        switch(task->tk_status) {
        case -NFS4ERR_DELAY:
                rpc_delay(task, NFS4_POLL_RETRY_MAX);
                return -EAGAIN;
        default:
                nfs4_schedule_lease_recovery(clp);
        }
        return 0;
}

static void nfs41_sequence_call_done(struct rpc_task *task, void *data)
{
        struct nfs4_sequence_data *calldata = data;
        struct nfs_client *clp = calldata->clp;

        if (!nfs41_sequence_done(task, task->tk_msg.rpc_resp))
                return;

        if (task->tk_status < 0) {
                dprintk("%s ERROR %d\n", __func__, task->tk_status);
                if (atomic_read(&clp->cl_count) == 1)
                        goto out;

                if (nfs41_sequence_handle_errors(task, clp) == -EAGAIN) {
                        rpc_restart_call_prepare(task);
                        return;
                }
        }
        dprintk("%s rpc_cred %p\n", __func__, task->tk_msg.rpc_cred);
out:
        dprintk("<-- %s\n", __func__);
}

static void nfs41_sequence_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_sequence_data *calldata = data;
        struct nfs_client *clp = calldata->clp;
        struct nfs4_sequence_args *args;
        struct nfs4_sequence_res *res;

        args = task->tk_msg.rpc_argp;
        res = task->tk_msg.rpc_resp;

        nfs41_setup_sequence(clp->cl_session, args, res, task);
}

static const struct rpc_call_ops nfs41_sequence_ops = {
        .rpc_call_done = nfs41_sequence_call_done,
        .rpc_call_prepare = nfs41_sequence_prepare,
        .rpc_release = nfs41_sequence_release,
};

static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp,
                struct rpc_cred *cred,
                bool is_privileged)
{
        struct nfs4_sequence_data *calldata;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SEQUENCE],
                .rpc_cred = cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = clp->cl_rpcclient,
                .rpc_message = &msg,
                .callback_ops = &nfs41_sequence_ops,
                .flags = RPC_TASK_ASYNC | RPC_TASK_SOFT,
        };

        if (!atomic_inc_not_zero(&clp->cl_count))
                return ERR_PTR(-EIO);
        calldata = kzalloc(sizeof(*calldata), GFP_NOFS);
        if (calldata == NULL) {
                nfs_put_client(clp);
                return ERR_PTR(-ENOMEM);
        }
        nfs41_init_sequence(&calldata->args, &calldata->res, 0);
        if (is_privileged)
                nfs4_set_sequence_privileged(&calldata->args);
        msg.rpc_argp = &calldata->args;
        msg.rpc_resp = &calldata->res;
        calldata->clp = clp;
        task_setup_data.callback_data = calldata;

        return rpc_run_task(&task_setup_data);
}

static int nfs41_proc_async_sequence(struct nfs_client *clp, struct rpc_cred *cred, unsigned renew_flags)
{
        struct rpc_task *task;
        int ret = 0;

        if ((renew_flags & NFS4_RENEW_TIMEOUT) == 0)
                return 0;
        task = _nfs41_proc_sequence(clp, cred, false);
        if (IS_ERR(task))
                ret = PTR_ERR(task);
        else
                rpc_put_task_async(task);
        dprintk("<-- %s status=%d\n", __func__, ret);
        return ret;
}

static int nfs4_proc_sequence(struct nfs_client *clp, struct rpc_cred *cred)
{
        struct rpc_task *task;
        int ret;

        task = _nfs41_proc_sequence(clp, cred, true);
        if (IS_ERR(task)) {
                ret = PTR_ERR(task);
                goto out;
        }
        ret = rpc_wait_for_completion_task(task);
        if (!ret) {
                struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;

                if (task->tk_status == 0)
                        nfs41_handle_sequence_flag_errors(clp, res->sr_status_flags);
                ret = task->tk_status;
        }
        rpc_put_task(task);
out:
        dprintk("<-- %s status=%d\n", __func__, ret);
        return ret;
}

struct nfs4_reclaim_complete_data {
        struct nfs_client *clp;
        struct nfs41_reclaim_complete_args arg;
        struct nfs41_reclaim_complete_res res;
};

static void nfs4_reclaim_complete_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_reclaim_complete_data *calldata = data;

        nfs41_setup_sequence(calldata->clp->cl_session,
                        &calldata->arg.seq_args,
                        &calldata->res.seq_res,
                        task);
}

static int nfs41_reclaim_complete_handle_errors(struct rpc_task *task, struct nfs_client *clp)
{
        switch(task->tk_status) {
        case 0:
        case -NFS4ERR_COMPLETE_ALREADY:
        case -NFS4ERR_WRONG_CRED: /* What to do here? */
                break;
        case -NFS4ERR_DELAY:
                rpc_delay(task, NFS4_POLL_RETRY_MAX);
                /* fall through */
        case -NFS4ERR_RETRY_UNCACHED_REP:
                return -EAGAIN;
        default:
                nfs4_schedule_lease_recovery(clp);
        }
        return 0;
}

static void nfs4_reclaim_complete_done(struct rpc_task *task, void *data)
{
        struct nfs4_reclaim_complete_data *calldata = data;
        struct nfs_client *clp = calldata->clp;
        struct nfs4_sequence_res *res = &calldata->res.seq_res;

        dprintk("--> %s\n", __func__);
        if (!nfs41_sequence_done(task, res))
                return;

        if (nfs41_reclaim_complete_handle_errors(task, clp) == -EAGAIN) {
                rpc_restart_call_prepare(task);
                return;
        }
        dprintk("<-- %s\n", __func__);
}

static void nfs4_free_reclaim_complete_data(void *data)
{
        struct nfs4_reclaim_complete_data *calldata = data;

        kfree(calldata);
}

static const struct rpc_call_ops nfs4_reclaim_complete_call_ops = {
        .rpc_call_prepare = nfs4_reclaim_complete_prepare,
        .rpc_call_done = nfs4_reclaim_complete_done,
        .rpc_release = nfs4_free_reclaim_complete_data,
};

/*
 * Issue a global reclaim complete.
 */
static int nfs41_proc_reclaim_complete(struct nfs_client *clp)
{
        struct nfs4_reclaim_complete_data *calldata;
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RECLAIM_COMPLETE],
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = clp->cl_rpcclient,
                .rpc_message = &msg,
                .callback_ops = &nfs4_reclaim_complete_call_ops,
                .flags = RPC_TASK_ASYNC,
        };
        int status = -ENOMEM;

        dprintk("--> %s\n", __func__);
        calldata = kzalloc(sizeof(*calldata), GFP_NOFS);
        if (calldata == NULL)
                goto out;
        calldata->clp = clp;
        calldata->arg.one_fs = 0;

        nfs41_init_sequence(&calldata->arg.seq_args, &calldata->res.seq_res, 0);
        nfs4_set_sequence_privileged(&calldata->arg.seq_args);
        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)) {
                status = PTR_ERR(task);
                goto out;
        }
        status = nfs4_wait_for_completion_rpc_task(task);
        if (status == 0)
                status = task->tk_status;
        rpc_put_task(task);
        return 0;
out:
        dprintk("<-- %s status=%d\n", __func__, status);
        return status;
}

static void
nfs4_layoutget_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutget *lgp = calldata;
        struct nfs_server *server = NFS_SERVER(lgp->args.inode);
        struct nfs4_session *session = nfs4_get_session(server);

        dprintk("--> %s\n", __func__);
        /* Note the is a race here, where a CB_LAYOUTRECALL can come in
         * right now covering the LAYOUTGET we are about to send.
         * However, that is not so catastrophic, and there seems
         * to be no way to prevent it completely.
         */
        if (nfs41_setup_sequence(session, &lgp->args.seq_args,
                                &lgp->res.seq_res, task))
                return;
        if (pnfs_choose_layoutget_stateid(&lgp->args.stateid,
                                          NFS_I(lgp->args.inode)->layout,
                                          lgp->args.ctx->state)) {
                rpc_exit(task, NFS4_OK);
        }
}

static void nfs4_layoutget_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutget *lgp = calldata;
        struct inode *inode = lgp->args.inode;
        struct nfs_server *server = NFS_SERVER(inode);
        struct pnfs_layout_hdr *lo;
        struct nfs4_state *state = NULL;
        unsigned long timeo, giveup;

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

        if (!nfs41_sequence_done(task, &lgp->res.seq_res))
                goto out;

        switch (task->tk_status) {
        case 0:
                goto out;
        case -NFS4ERR_LAYOUTTRYLATER:
        case -NFS4ERR_RECALLCONFLICT:
                timeo = rpc_get_timeout(task->tk_client);
                giveup = lgp->args.timestamp + timeo;
                if (time_after(giveup, jiffies))
                        task->tk_status = -NFS4ERR_DELAY;
                break;
        case -NFS4ERR_EXPIRED:
        case -NFS4ERR_BAD_STATEID:
                spin_lock(&inode->i_lock);
                lo = NFS_I(inode)->layout;
                if (!lo || list_empty(&lo->plh_segs)) {
                        spin_unlock(&inode->i_lock);
                        /* If the open stateid was bad, then recover it. */
                        state = lgp->args.ctx->state;
                } else {
                        LIST_HEAD(head);

                        pnfs_mark_matching_lsegs_invalid(lo, &head, NULL);
                        spin_unlock(&inode->i_lock);
                        /* Mark the bad layout state as invalid, then
                         * retry using the open stateid. */
                        pnfs_free_lseg_list(&head);
                }
        }
        if (nfs4_async_handle_error(task, server, state) == -EAGAIN)
                rpc_restart_call_prepare(task);
out:
        dprintk("<-- %s\n", __func__);
}

static size_t max_response_pages(struct nfs_server *server)
{
        u32 max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
        return nfs_page_array_len(0, max_resp_sz);
}

static void nfs4_free_pages(struct page **pages, size_t size)
{
        int i;

        if (!pages)
                return;

        for (i = 0; i < size; i++) {
                if (!pages[i])
                        break;
                __free_page(pages[i]);
        }
        kfree(pages);
}

static struct page **nfs4_alloc_pages(size_t size, gfp_t gfp_flags)
{
        struct page **pages;
        int i;

        pages = kcalloc(size, sizeof(struct page *), gfp_flags);
        if (!pages) {
                dprintk("%s: can't alloc array of %zu pages\n", __func__, size);
                return NULL;
        }

        for (i = 0; i < size; i++) {
                pages[i] = alloc_page(gfp_flags);
                if (!pages[i]) {
                        dprintk("%s: failed to allocate page\n", __func__);
                        nfs4_free_pages(pages, size);
                        return NULL;
                }
        }

        return pages;
}

static void nfs4_layoutget_release(void *calldata)
{
        struct nfs4_layoutget *lgp = calldata;
        struct inode *inode = lgp->args.inode;
        struct nfs_server *server = NFS_SERVER(inode);
        size_t max_pages = max_response_pages(server);

        dprintk("--> %s\n", __func__);
        nfs4_free_pages(lgp->args.layout.pages, max_pages);
        pnfs_put_layout_hdr(NFS_I(inode)->layout);
        put_nfs_open_context(lgp->args.ctx);
        kfree(calldata);
        dprintk("<-- %s\n", __func__);
}

static const struct rpc_call_ops nfs4_layoutget_call_ops = {
        .rpc_call_prepare = nfs4_layoutget_prepare,
        .rpc_call_done = nfs4_layoutget_done,
        .rpc_release = nfs4_layoutget_release,
};

struct pnfs_layout_segment *
nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
{
        struct inode *inode = lgp->args.inode;
        struct nfs_server *server = NFS_SERVER(inode);
        size_t max_pages = max_response_pages(server);
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LAYOUTGET],
                .rpc_argp = &lgp->args,
                .rpc_resp = &lgp->res,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_layoutget_call_ops,
                .callback_data = lgp,
                .flags = RPC_TASK_ASYNC,
        };
        struct pnfs_layout_segment *lseg = NULL;
        int status = 0;

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

        lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
        if (!lgp->args.layout.pages) {
                nfs4_layoutget_release(lgp);
                return ERR_PTR(-ENOMEM);
        }
        lgp->args.layout.pglen = max_pages * PAGE_SIZE;
        lgp->args.timestamp = jiffies;

        lgp->res.layoutp = &lgp->args.layout;
        lgp->res.seq_res.sr_slot = NULL;
        nfs41_init_sequence(&lgp->args.seq_args, &lgp->res.seq_res, 0);

        /* nfs4_layoutget_release calls pnfs_put_layout_hdr */
        pnfs_get_layout_hdr(NFS_I(inode)->layout);

        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return ERR_CAST(task);
        status = nfs4_wait_for_completion_rpc_task(task);
        if (status == 0)
                status = task->tk_status;
        /* if layoutp->len is 0, nfs4_layoutget_prepare called rpc_exit */
        if (status == 0 && lgp->res.layoutp->len)
                lseg = pnfs_layout_process(lgp);
        rpc_put_task(task);
        dprintk("<-- %s status=%d\n", __func__, status);
        if (status)
                return ERR_PTR(status);
        return lseg;
}

static void
nfs4_layoutreturn_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutreturn *lrp = calldata;

        dprintk("--> %s\n", __func__);
        nfs41_setup_sequence(lrp->clp->cl_session,
                        &lrp->args.seq_args,
                        &lrp->res.seq_res,
                        task);
}

static void nfs4_layoutreturn_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutreturn *lrp = calldata;
        struct nfs_server *server;

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

        if (!nfs41_sequence_done(task, &lrp->res.seq_res))
                return;

        server = NFS_SERVER(lrp->args.inode);
        if (nfs4_async_handle_error(task, server, NULL) == -EAGAIN) {
                rpc_restart_call_prepare(task);
                return;
        }
        dprintk("<-- %s\n", __func__);
}

static void nfs4_layoutreturn_release(void *calldata)
{
        struct nfs4_layoutreturn *lrp = calldata;
        struct pnfs_layout_hdr *lo = lrp->args.layout;

        dprintk("--> %s\n", __func__);
        spin_lock(&lo->plh_inode->i_lock);
        if (lrp->res.lrs_present)
                pnfs_set_layout_stateid(lo, &lrp->res.stateid, true);
        lo->plh_block_lgets--;
        spin_unlock(&lo->plh_inode->i_lock);
        pnfs_put_layout_hdr(lrp->args.layout);
        kfree(calldata);
        dprintk("<-- %s\n", __func__);
}

static const struct rpc_call_ops nfs4_layoutreturn_call_ops = {
        .rpc_call_prepare = nfs4_layoutreturn_prepare,
        .rpc_call_done = nfs4_layoutreturn_done,
        .rpc_release = nfs4_layoutreturn_release,
};

int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp)
{
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LAYOUTRETURN],
                .rpc_argp = &lrp->args,
                .rpc_resp = &lrp->res,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = lrp->clp->cl_rpcclient,
                .rpc_message = &msg,
                .callback_ops = &nfs4_layoutreturn_call_ops,
                .callback_data = lrp,
        };
        int status;

        dprintk("--> %s\n", __func__);
        nfs41_init_sequence(&lrp->args.seq_args, &lrp->res.seq_res, 1);
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = task->tk_status;
        dprintk("<-- %s status=%d\n", __func__, status);
        rpc_put_task(task);
        return status;
}

/*
 * Retrieve the list of Data Server devices from the MDS.
 */
static int _nfs4_getdevicelist(struct nfs_server *server,
                                    const struct nfs_fh *fh,
                                    struct pnfs_devicelist *devlist)
{
        struct nfs4_getdevicelist_args args = {
                .fh = fh,
                .layoutclass = server->pnfs_curr_ld->id,
        };
        struct nfs4_getdevicelist_res res = {
                .devlist = devlist,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETDEVICELIST],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        int status;

        dprintk("--> %s\n", __func__);
        status = nfs4_call_sync(server->client, server, &msg, &args.seq_args,
                                &res.seq_res, 0);
        dprintk("<-- %s status=%d\n", __func__, status);
        return status;
}

int nfs4_proc_getdevicelist(struct nfs_server *server,
                            const struct nfs_fh *fh,
                            struct pnfs_devicelist *devlist)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = nfs4_handle_exception(server,
                                _nfs4_getdevicelist(server, fh, devlist),
                                &exception);
        } while (exception.retry);

        dprintk("%s: err=%d, num_devs=%u\n", __func__,
                err, devlist->num_devs);

        return err;
}
EXPORT_SYMBOL_GPL(nfs4_proc_getdevicelist);

static int
_nfs4_proc_getdeviceinfo(struct nfs_server *server, struct pnfs_device *pdev)
{
        struct nfs4_getdeviceinfo_args args = {
                .pdev = pdev,
        };
        struct nfs4_getdeviceinfo_res res = {
                .pdev = pdev,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETDEVICEINFO],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        int status;

        dprintk("--> %s\n", __func__);
        status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
        dprintk("<-- %s status=%d\n", __func__, status);

        return status;
}

int nfs4_proc_getdeviceinfo(struct nfs_server *server, struct pnfs_device *pdev)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = nfs4_handle_exception(server,
                                        _nfs4_proc_getdeviceinfo(server, pdev),
                                        &exception);
        } while (exception.retry);
        return err;
}
EXPORT_SYMBOL_GPL(nfs4_proc_getdeviceinfo);

static void nfs4_layoutcommit_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutcommit_data *data = calldata;
        struct nfs_server *server = NFS_SERVER(data->args.inode);
        struct nfs4_session *session = nfs4_get_session(server);

        nfs41_setup_sequence(session,
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static void
nfs4_layoutcommit_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutcommit_data *data = calldata;
        struct nfs_server *server = NFS_SERVER(data->args.inode);

        if (!nfs41_sequence_done(task, &data->res.seq_res))
                return;

        switch (task->tk_status) { /* Just ignore these failures */
        case -NFS4ERR_DELEG_REVOKED: /* layout was recalled */
        case -NFS4ERR_BADIOMODE:     /* no IOMODE_RW layout for range */
        case -NFS4ERR_BADLAYOUT:     /* no layout */
        case -NFS4ERR_GRACE:        /* loca_recalim always false */
                task->tk_status = 0;
                break;
        case 0:
                nfs_post_op_update_inode_force_wcc(data->args.inode,
                                                   data->res.fattr);
                break;
        default:
                if (nfs4_async_handle_error(task, server, NULL) == -EAGAIN) {
                        rpc_restart_call_prepare(task);
                        return;
                }
        }
}

static void nfs4_layoutcommit_release(void *calldata)
{
        struct nfs4_layoutcommit_data *data = calldata;

        pnfs_cleanup_layoutcommit(data);
        put_rpccred(data->cred);
        kfree(data);
}

static const struct rpc_call_ops nfs4_layoutcommit_ops = {
        .rpc_call_prepare = nfs4_layoutcommit_prepare,
        .rpc_call_done = nfs4_layoutcommit_done,
        .rpc_release = nfs4_layoutcommit_release,
};

int
nfs4_proc_layoutcommit(struct nfs4_layoutcommit_data *data, bool sync)
{
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LAYOUTCOMMIT],
                .rpc_argp = &data->args,
                .rpc_resp = &data->res,
                .rpc_cred = data->cred,
        };
        struct rpc_task_setup task_setup_data = {
                .task = &data->task,
                .rpc_client = NFS_CLIENT(data->args.inode),
                .rpc_message = &msg,
                .callback_ops = &nfs4_layoutcommit_ops,
                .callback_data = data,
                .flags = RPC_TASK_ASYNC,
        };
        struct rpc_task *task;
        int status = 0;

        dprintk("NFS: %4d initiating layoutcommit call. sync %d "
                "lbw: %llu inode %lu\n",
                data->task.tk_pid, sync,
                data->args.lastbytewritten,
                data->args.inode->i_ino);

        nfs41_init_sequence(&data->args.seq_args, &data->res.seq_res, 1);
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        if (sync == false)
                goto out;
        status = nfs4_wait_for_completion_rpc_task(task);
        if (status != 0)
                goto out;
        status = task->tk_status;
out:
        dprintk("%s: status %d\n", __func__, status);
        rpc_put_task(task);
        return status;
}

static int
_nfs41_proc_secinfo_no_name(struct nfs_server *server, struct nfs_fh *fhandle,
                    struct nfs_fsinfo *info, struct nfs4_secinfo_flavors *flavors)
{
        struct nfs41_secinfo_no_name_args args = {
                .style = SECINFO_STYLE_CURRENT_FH,
        };
        struct nfs4_secinfo_res res = {
                .flavors = flavors,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SECINFO_NO_NAME],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        return nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
}

static int
nfs41_proc_secinfo_no_name(struct nfs_server *server, struct nfs_fh *fhandle,
                           struct nfs_fsinfo *info, struct nfs4_secinfo_flavors *flavors)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs41_proc_secinfo_no_name(server, fhandle, info, flavors);
                switch (err) {
                case 0:
                case -NFS4ERR_WRONGSEC:
                case -NFS4ERR_NOTSUPP:
                        goto out;
                default:
                        err = nfs4_handle_exception(server, err, &exception);
                }
        } while (exception.retry);
out:
        return err;
}

static int
nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
                    struct nfs_fsinfo *info)
{
        int err;
        struct page *page;
        rpc_authflavor_t flavor;
        struct nfs4_secinfo_flavors *flavors;

        page = alloc_page(GFP_KERNEL);
        if (!page) {
                err = -ENOMEM;
                goto out;
        }

        flavors = page_address(page);
        err = nfs41_proc_secinfo_no_name(server, fhandle, info, flavors);

        /*
         * Fall back on "guess and check" method if
         * the server doesn't support SECINFO_NO_NAME
         */
        if (err == -NFS4ERR_WRONGSEC || err == -NFS4ERR_NOTSUPP) {
                err = nfs4_find_root_sec(server, fhandle, info);
                goto out_freepage;
        }
        if (err)
                goto out_freepage;

        flavor = nfs_find_best_sec(flavors);
        if (err == 0)
                err = nfs4_lookup_root_sec(server, fhandle, info, flavor);

out_freepage:
        put_page(page);
        if (err == -EACCES)
                return -EPERM;
out:
        return err;
}

static int _nfs41_test_stateid(struct nfs_server *server, nfs4_stateid *stateid)
{
        int status;
        struct nfs41_test_stateid_args args = {
                .stateid = stateid,
        };
        struct nfs41_test_stateid_res res;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_TEST_STATEID],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        dprintk("NFS call  test_stateid %p\n", stateid);
        nfs41_init_sequence(&args.seq_args, &res.seq_res, 0);
        nfs4_set_sequence_privileged(&args.seq_args);
        status = nfs4_call_sync_sequence(server->client, server, &msg,
                        &args.seq_args, &res.seq_res);
        if (status != NFS_OK) {
                dprintk("NFS reply test_stateid: failed, %d\n", status);
                return status;
        }
        dprintk("NFS reply test_stateid: succeeded, %d\n", -res.status);
        return -res.status;
}

/**
 * nfs41_test_stateid - perform a TEST_STATEID operation
 *
 * @server: server / transport on which to perform the operation
 * @stateid: state ID to test
 *
 * Returns NFS_OK if the server recognizes that "stateid" is valid.
 * Otherwise a negative NFS4ERR value is returned if the operation
 * failed or the state ID is not currently valid.
 */
static int nfs41_test_stateid(struct nfs_server *server, nfs4_stateid *stateid)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs41_test_stateid(server, stateid);
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_free_stateid(struct nfs_server *server, nfs4_stateid *stateid)
{
        struct nfs41_free_stateid_args args = {
                .stateid = stateid,
        };
        struct nfs41_free_stateid_res res;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_FREE_STATEID],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        int status;

        dprintk("NFS call  free_stateid %p\n", stateid);
        nfs41_init_sequence(&args.seq_args, &res.seq_res, 0);
        nfs4_set_sequence_privileged(&args.seq_args);
        status = nfs4_call_sync_sequence(server->client, server, &msg,
                        &args.seq_args, &res.seq_res);
        dprintk("NFS reply free_stateid: %d\n", status);
        return status;
}

/**
 * nfs41_free_stateid - perform a FREE_STATEID operation
 *
 * @server: server / transport on which to perform the operation
 * @stateid: state ID to release
 *
 * Returns NFS_OK if the server freed "stateid".  Otherwise a
 * negative NFS4ERR value is returned.
 */
static int nfs41_free_stateid(struct nfs_server *server, nfs4_stateid *stateid)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_free_stateid(server, stateid);
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static bool nfs41_match_stateid(const nfs4_stateid *s1,
                const nfs4_stateid *s2)
{
        if (memcmp(s1->other, s2->other, sizeof(s1->other)) != 0)
                return false;

        if (s1->seqid == s2->seqid)
                return true;
        if (s1->seqid == 0 || s2->seqid == 0)
                return true;

        return false;
}

#endif /* CONFIG_NFS_V4_1 */

static bool nfs4_match_stateid(const nfs4_stateid *s1,
                const nfs4_stateid *s2)
{
        return nfs4_stateid_match(s1, s2);
}


static const struct nfs4_state_recovery_ops nfs40_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,
        .establish_clid = nfs4_init_clientid,
        .get_clid_cred  = nfs4_get_setclientid_cred,
        .detect_trunking = nfs40_discover_server_trunking,
};

#if defined(CONFIG_NFS_V4_1)
static const struct nfs4_state_recovery_ops nfs41_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,
        .establish_clid = nfs41_init_clientid,
        .get_clid_cred  = nfs4_get_exchange_id_cred,
        .reclaim_complete = nfs41_proc_reclaim_complete,
        .detect_trunking = nfs41_discover_server_trunking,
};
#endif /* CONFIG_NFS_V4_1 */

static const struct nfs4_state_recovery_ops nfs40_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,
        .establish_clid = nfs4_init_clientid,
        .get_clid_cred  = nfs4_get_setclientid_cred,
};

#if defined(CONFIG_NFS_V4_1)
static const struct nfs4_state_recovery_ops nfs41_nograce_recovery_ops = {
        .owner_flag_bit = NFS_OWNER_RECLAIM_NOGRACE,
        .state_flag_bit = NFS_STATE_RECLAIM_NOGRACE,
        .recover_open   = nfs41_open_expired,
        .recover_lock   = nfs41_lock_expired,
        .establish_clid = nfs41_init_clientid,
        .get_clid_cred  = nfs4_get_exchange_id_cred,
};
#endif /* CONFIG_NFS_V4_1 */

static const struct nfs4_state_maintenance_ops nfs40_state_renewal_ops = {
        .sched_state_renewal = nfs4_proc_async_renew,
        .get_state_renewal_cred_locked = nfs4_get_renew_cred_locked,
        .renew_lease = nfs4_proc_renew,
};

#if defined(CONFIG_NFS_V4_1)
static const struct nfs4_state_maintenance_ops nfs41_state_renewal_ops = {
        .sched_state_renewal = nfs41_proc_async_sequence,
        .get_state_renewal_cred_locked = nfs4_get_machine_cred_locked,
        .renew_lease = nfs4_proc_sequence,
};
#endif

static const struct nfs4_minor_version_ops nfs_v4_0_minor_ops = {
        .minor_version = 0,
        .call_sync = _nfs4_call_sync,
        .match_stateid = nfs4_match_stateid,
        .find_root_sec = nfs4_find_root_sec,
        .reboot_recovery_ops = &nfs40_reboot_recovery_ops,
        .nograce_recovery_ops = &nfs40_nograce_recovery_ops,
        .state_renewal_ops = &nfs40_state_renewal_ops,
};

#if defined(CONFIG_NFS_V4_1)
static const struct nfs4_minor_version_ops nfs_v4_1_minor_ops = {
        .minor_version = 1,
        .call_sync = nfs4_call_sync_sequence,
        .match_stateid = nfs41_match_stateid,
        .find_root_sec = nfs41_find_root_sec,
        .reboot_recovery_ops = &nfs41_reboot_recovery_ops,
        .nograce_recovery_ops = &nfs41_nograce_recovery_ops,
        .state_renewal_ops = &nfs41_state_renewal_ops,
};
#endif

const struct nfs4_minor_version_ops *nfs_v4_minor_ops[] = {
        [0] = &nfs_v4_0_minor_ops,
#if defined(CONFIG_NFS_V4_1)
        [1] = &nfs_v4_1_minor_ops,
#endif
};

const struct inode_operations nfs4_dir_inode_operations = {
        .create         = nfs_create,
        .lookup         = nfs_lookup,
        .atomic_open    = nfs_atomic_open,
        .link           = nfs_link,
        .unlink         = nfs_unlink,
        .symlink        = nfs_symlink,
        .mkdir          = nfs_mkdir,
        .rmdir          = nfs_rmdir,
        .mknod          = nfs_mknod,
        .rename         = nfs_rename,
        .permission     = nfs_permission,
        .getattr        = nfs_getattr,
        .setattr        = nfs_setattr,
        .getxattr       = generic_getxattr,
        .setxattr       = generic_setxattr,
        .listxattr      = generic_listxattr,
        .removexattr    = generic_removexattr,
};

static const struct inode_operations nfs4_file_inode_operations = {
        .permission     = nfs_permission,
        .getattr        = nfs_getattr,
        .setattr        = nfs_setattr,
        .getxattr       = generic_getxattr,
        .setxattr       = generic_setxattr,
        .listxattr      = generic_listxattr,
        .removexattr    = generic_removexattr,
};

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,
        .file_ops       = &nfs4_file_operations,
        .getroot        = nfs4_proc_get_root,
        .submount       = nfs4_submount,
        .try_mount      = nfs4_try_mount,
        .getattr        = nfs4_proc_getattr,
        .setattr        = nfs4_proc_setattr,
        .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_rpc_prepare = nfs4_proc_unlink_rpc_prepare,
        .unlink_done    = nfs4_proc_unlink_done,
        .rename         = nfs4_proc_rename,
        .rename_setup   = nfs4_proc_rename_setup,
        .rename_rpc_prepare = nfs4_proc_rename_rpc_prepare,
        .rename_done    = nfs4_proc_rename_done,
        .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_pageio_init = pnfs_pageio_init_read,
        .read_rpc_prepare = nfs4_proc_read_rpc_prepare,
        .read_done      = nfs4_read_done,
        .write_setup    = nfs4_proc_write_setup,
        .write_pageio_init = pnfs_pageio_init_write,
        .write_rpc_prepare = nfs4_proc_write_rpc_prepare,
        .write_done     = nfs4_write_done,
        .commit_setup   = nfs4_proc_commit_setup,
        .commit_rpc_prepare = nfs4_proc_commit_rpc_prepare,
        .commit_done    = nfs4_commit_done,
        .lock           = nfs4_proc_lock,
        .clear_acl_cache = nfs4_zap_acl_attr,
        .close_context  = nfs4_close_context,
        .open_context   = nfs4_atomic_open,
        .have_delegation = nfs4_have_delegation,
        .return_delegation = nfs4_inode_return_delegation,
        .alloc_client   = nfs4_alloc_client,
        .init_client    = nfs4_init_client,
        .free_client    = nfs4_free_client,
        .create_server  = nfs4_create_server,
        .clone_server   = nfs_clone_server,
};

static const struct xattr_handler nfs4_xattr_nfs4_acl_handler = {
        .prefix = XATTR_NAME_NFSV4_ACL,
        .list   = nfs4_xattr_list_nfs4_acl,
        .get    = nfs4_xattr_get_nfs4_acl,
        .set    = nfs4_xattr_set_nfs4_acl,
};

const struct xattr_handler *nfs4_xattr_handlers[] = {
        &nfs4_xattr_nfs4_acl_handler,
        NULL
};

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