/*
 *  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/sunrpc/gss_api.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/sunrpc/bc_xprt.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"

#define NFSDBG_FACILITY         NFSDBG_PROC

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

#define NFS4_MAX_LOOP_ON_RECOVER (10)

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 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 *, struct nfs4_state *);
static int nfs41_free_stateid(struct nfs_server *, struct nfs4_state *);
#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:
                return -EREMOTEIO;
        case -NFS4ERR_WRONGSEC:
                return -EPERM;
        case -NFS4ERR_BADOWNER:
        case -NFS4ERR_BADNAME:
                return -EINVAL;
        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[2] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_SIZE
        | FATTR4_WORD0_FSID
        | FATTR4_WORD0_FILEID,
        FATTR4_WORD1_MODE
        | FATTR4_WORD1_NUMLINKS
        | FATTR4_WORD1_OWNER
        | FATTR4_WORD1_OWNER_GROUP
        | FATTR4_WORD1_RAWDEV
        | FATTR4_WORD1_SPACE_USED
        | FATTR4_WORD1_TIME_ACCESS
        | FATTR4_WORD1_TIME_METADATA
        | FATTR4_WORD1_TIME_MODIFY
};

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

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

const u32 nfs4_fsinfo_bitmap[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;

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

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

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

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

        might_sleep();

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

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

        might_sleep();

        if (*timeout <= 0)
                *timeout = NFS4_POLL_RETRY_MIN;
        if (*timeout > NFS4_POLL_RETRY_MAX)
                *timeout = NFS4_POLL_RETRY_MAX;
        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 (nfs_have_delegation(inode, FMODE_READ)) {
                                nfs_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)
                                nfs_remove_bad_delegation(state->inode);
                        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_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);
                        exception->retry = 1;
                        break;
#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:
                case -EKEYEXPIRED:
                        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)

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

        BUG_ON(slotid < 0 || slotid >= NFS4_MAX_SLOT_TABLE);
        /* clear used bit in bitmap */
        __clear_bit(slotid, tbl->used_slots);

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

/*
 * Signal state manager thread if session fore channel is drained
 */
static void nfs4_check_drain_fc_complete(struct nfs4_session *ses)
{
        struct rpc_task *task;

        if (!test_bit(NFS4_SESSION_DRAINING, &ses->session_state)) {
                task = rpc_wake_up_next(&ses->fc_slot_table.slot_tbl_waitq);
                if (task)
                        rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
                return;
        }

        if (ses->fc_slot_table.highest_used_slotid != -1)
                return;

        dprintk("%s COMPLETE: Session Fore Channel Drained\n", __func__);
        complete(&ses->fc_slot_table.complete);
}

/*
 * Signal state manager thread if session back channel is drained
 */
void nfs4_check_drain_bc_complete(struct nfs4_session *ses)
{
        if (!test_bit(NFS4_SESSION_DRAINING, &ses->session_state) ||
            ses->bc_slot_table.highest_used_slotid != -1)
                return;
        dprintk("%s COMPLETE: Session Back Channel Drained\n", __func__);
        complete(&ses->bc_slot_table.complete);
}

static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res)
{
        struct nfs4_slot_table *tbl;

        tbl = &res->sr_session->fc_slot_table;
        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;
        }

        spin_lock(&tbl->slot_tbl_lock);
        nfs4_free_slot(tbl, res->sr_slot - tbl->slots);
        nfs4_check_drain_fc_complete(res->sr_session);
        spin_unlock(&tbl->slot_tbl_lock);
        res->sr_slot = NULL;
}

static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)
{
        unsigned long timestamp;
        struct nfs_client *clp;

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

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

        /* Check the SEQUENCE operation status */
        switch (res->sr_status) {
        case 0:
                /* Update the slot's sequence and clientid lease timer */
                ++res->sr_slot->seq_nr;
                timestamp = res->sr_renewal_time;
                clp = res->sr_session->clp;
                do_renew_lease(clp, timestamp);
                /* Check sequence flags */
                if (res->sr_status_flags != 0)
                        nfs4_schedule_lease_recovery(clp);
                break;
        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=%td seq=%d: Operation in progress\n",
                        __func__,
                        res->sr_slot - res->sr_session->fc_slot_table.slots,
                        res->sr_slot->seq_nr);
                goto out_retry;
        default:
                /* Just update the slot sequence no. */
                ++res->sr_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 1;
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_session == NULL)
                return 1;
        return nfs41_sequence_done(task, res);
}

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

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

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

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

        tbl = &session->fc_slot_table;

        spin_lock(&tbl->slot_tbl_lock);
        if (test_bit(NFS4_SESSION_DRAINING, &session->session_state) &&
            !rpc_task_has_priority(task, RPC_PRIORITY_PRIVILEGED)) {
                /* The state manager will wait until the slot table is empty */
                rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
                spin_unlock(&tbl->slot_tbl_lock);
                dprintk("%s session is draining\n", __func__);
                return -EAGAIN;
        }

        if (!rpc_queue_empty(&tbl->slot_tbl_waitq) &&
            !rpc_task_has_priority(task, RPC_PRIORITY_PRIVILEGED)) {
                rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
                spin_unlock(&tbl->slot_tbl_lock);
                dprintk("%s enforce FIFO order\n", __func__);
                return -EAGAIN;
        }

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

        rpc_task_set_priority(task, RPC_PRIORITY_NORMAL);
        slot = tbl->slots + slotid;
        args->sa_session = session;
        args->sa_slotid = slotid;
        args->sa_cache_this = cache_reply;

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

        res->sr_session = session;
        res->sr_slot = slot;
        res->sr_renewal_time = 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;
        return 0;
}
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,
                        int cache_reply,
                        struct rpc_task *task)
{
        struct nfs4_session *session = nfs4_get_session(server);
        int ret = 0;

        if (session == NULL) {
                args->sa_session = NULL;
                res->sr_session = NULL;
                goto out;
        }

        dprintk("--> %s clp %p session %p sr_slot %td\n",
                __func__, session->clp, session, res->sr_slot ?
                        res->sr_slot - session->fc_slot_table.slots : -1);

        ret = nfs41_setup_sequence(session, args, res, cache_reply,
                                   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;
        int cache_reply;
};

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

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

        if (nfs4_setup_sequence(data->seq_server, data->seq_args,
                                data->seq_res, data->cache_reply, task))
                return;
        rpc_call_start(task);
}

static void nfs41_call_priv_sync_prepare(struct rpc_task *task, void *calldata)
{
        rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
        nfs41_call_sync_prepare(task, calldata);
}

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);
}

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

struct rpc_call_ops nfs41_call_priv_sync_ops = {
        .rpc_call_prepare = nfs41_call_priv_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 cache_reply,
                                   int privileged)
{
        int ret;
        struct rpc_task *task;
        struct nfs41_call_sync_data data = {
                .seq_server = server,
                .seq_args = args,
                .seq_res = res,
                .cache_reply = cache_reply,
        };
        struct rpc_task_setup task_setup = {
                .rpc_client = clnt,
                .rpc_message = msg,
                .callback_ops = &nfs41_call_sync_ops,
                .callback_data = &data
        };

        res->sr_slot = NULL;
        if (privileged)
                task_setup.callback_ops = &nfs41_call_priv_sync_ops;
        task = rpc_run_task(&task_setup);
        if (IS_ERR(task))
                ret = PTR_ERR(task);
        else {
                ret = task->tk_status;
                rpc_put_task(task);
        }
        return ret;
}

int _nfs4_call_sync_session(struct rpc_clnt *clnt,
                            struct nfs_server *server,
                            struct rpc_message *msg,
                            struct nfs4_sequence_args *args,
                            struct nfs4_sequence_res *res,
                            int cache_reply)
{
        return nfs4_call_sync_sequence(clnt, server, msg, args, res, cache_reply, 0);
}

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

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)
{
        args->sa_session = res->sr_session = NULL;
        return rpc_call_sync(clnt, msg, 0);
}

static inline
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)
{
        return server->nfs_client->cl_mvops->call_sync(clnt, server, msg,
                                                args, res, cache_reply);
}

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

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

struct nfs4_opendata {
        struct kref kref;
        struct nfs_openargs o_arg;
        struct nfs_openres o_res;
        struct nfs_open_confirmargs c_arg;
        struct nfs_open_confirmres c_res;
        struct nfs4_string owner_name;
        struct nfs4_string group_name;
        struct nfs_fattr f_attr;
        struct nfs_fattr dir_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.dir_attr = &p->dir_attr;
        p->o_res.seqid = p->o_arg.seqid;
        p->c_res.seqid = p->c_arg.seqid;
        p->o_res.server = p->o_arg.server;
        nfs_fattr_init(&p->f_attr);
        nfs_fattr_init(&p->dir_attr);
        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);
        p->o_arg.clientid = server->nfs_client->cl_clientid;
        p->o_arg.id = sp->so_owner_id.id;
        p->o_arg.name = &dentry->d_name;
        p->o_arg.server = server;
        p->o_arg.bitmask = server->attr_bitmask;
        p->o_arg.dir_bitmask = server->cache_consistency_bitmask;
        p->o_arg.claim = NFS4_OPEN_CLAIM_NULL;
        if (flags & O_CREAT) {
                u32 *s;

                p->o_arg.u.attrs = &p->attrs;
                memcpy(&p->attrs, attrs, sizeof(p->attrs));
                s = (u32 *) p->o_arg.u.verifier.data;
                s[0] = jiffies;
                s[1] = current->pid;
        }
        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)
                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;
        nfs_mark_delegation_referenced(delegation);
        return 1;
}

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

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

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

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

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

        fmode &= (FMODE_READ|FMODE_WRITE);

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

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

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

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

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

        return ret;
}


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

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

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

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

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

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

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

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

                rcu_read_lock();
                delegation = rcu_dereference(NFS_I(inode)->delegation);
                if (delegation)
                        delegation_flags = delegation->flags;
                rcu_read_unlock();
                if (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",
                                        NFS_CLIENT(inode)->cl_server);
                } 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);
        }

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

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

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

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

        opendata = nfs4_opendata_alloc(ctx->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 &&
            memcmp(state->stateid.data, state->open_stateid.data, sizeof(state->stateid.data)) != 0) {
                write_seqlock(&state->seqlock);
                if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                        memcpy(state->stateid.data, state->open_stateid.data, sizeof(state->stateid.data));
                write_sequnlock(&state->seqlock);
        }
        return 0;
}

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

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

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

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

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

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

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

int nfs4_open_delegation_recall(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
{
        struct nfs4_exception exception = { };
        struct nfs_server *server = NFS_SERVER(state->inode);
        int err;
        do {
                err = _nfs4_open_delegation_recall(ctx, state, stateid);
                switch (err) {
                        case 0:
                        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:
                                nfs4_schedule_session_recovery(server->nfs_client->cl_session);
                                goto out;
                        case -NFS4ERR_STALE_CLIENTID:
                        case -NFS4ERR_STALE_STATEID:
                        case -NFS4ERR_EXPIRED:
                                /* Don't recall a delegation if it was lost */
                                nfs4_schedule_lease_recovery(server->nfs_client);
                                goto out;
                        case -ERESTARTSYS:
                                /*
                                 * The show must go on: exit, but mark the
                                 * stateid as needing recovery.
                                 */
                        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 -EKEYEXPIRED:
                                /*
                                 * User RPCSEC_GSS context has expired.
                                 * We cannot recover this stateid now, so
                                 * skip it and allow recovery thread to
                                 * proceed.
                                 */
                        case -ENOMEM:
                                err = 0;
                                goto out;
                }
                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) {
                memcpy(data->o_res.stateid.data, data->c_res.stateid.data,
                                sizeof(data->o_res.stateid.data));
                nfs_confirm_seqid(&data->owner->so_seqid, 0);
                renew_lease(data->o_res.server, data->timestamp);
                data->rpc_done = 1;
        }
}

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

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

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

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

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

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

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

                if (can_open_cached(data->state, data->o_arg.fmode, data->o_arg.open_flags))
                        goto out_no_action;
                rcu_read_lock();
                delegation = rcu_dereference(NFS_I(data->state->inode)->delegation);
                if (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 sequence id. */
        data->o_arg.id = sp->so_owner_id.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];
                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, 1, task))
                return;
        rpc_call_start(task);
        return;
unlock_no_action:
        rcu_read_unlock();
out_no_action:
        task->tk_action = NULL;

}

static void nfs4_recover_open_prepare(struct rpc_task *task, void *calldata)
{
        rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
        nfs4_open_prepare(task, calldata);
}

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) {
                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 const struct rpc_call_ops nfs4_recover_open_ops = {
        .rpc_call_prepare = nfs4_recover_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;

        kref_get(&data->kref);
        data->rpc_done = 0;
        data->rpc_status = 0;
        data->cancelled = 0;
        if (isrecover)
                task_setup_data.callback_ops = &nfs4_recover_open_ops;
        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);

        nfs_refresh_inode(dir, o_res->dir_attr);

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

        return status;
}

/*
 * 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);
                nfs_post_op_update_inode(dir, o_res->dir_attr);
        } else
                nfs_refresh_inode(dir, o_res->dir_attr);
        if ((o_res->rflags & NFS4_OPEN_RESULT_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_client_recover_expired_lease(struct nfs_client *clp)
{
        unsigned int loop;
        int ret;

        for (loop = NFS4_MAX_LOOP_ON_RECOVER; loop != 0; loop--) {
                ret = nfs4_wait_clnt_recover(clp);
                if (ret != 0)
                        break;
                if (!test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) &&
                    !test_bit(NFS4CLNT_CHECK_LEASE,&clp->cl_state))
                        break;
                nfs4_schedule_state_manager(clp);
                ret = -EIO;
        }
        return ret;
}

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 int nfs41_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        int status;
        struct nfs_server *server = NFS_SERVER(state->inode);

        status = nfs41_test_stateid(server, state);
        if (status == NFS_OK)
                return 0;
        nfs41_free_stateid(server, state);
        return nfs4_open_expired(sp, state);
}
#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;
}

/*
 * 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_state_owner  *sp;
        struct nfs4_state     *state = NULL;
        struct nfs_server       *server = NFS_SERVER(dir);
        struct nfs4_opendata *opendata;
        int status;

        /* Protect against reboot recovery conflicts */
        status = -ENOMEM;
        if (!(sp = nfs4_get_state_owner(server, cred))) {
                dprintk("nfs4_do_open: nfs4_get_state_owner failed!\n");
                goto out_err;
        }
        status = nfs4_recover_expired_lease(server);
        if (status != 0)
                goto err_put_state_owner;
        if (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 (dentry->d_inode != NULL)
                opendata->state = nfs4_get_open_state(dentry->d_inode, sp);

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

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

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


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

        do {
                status = _nfs4_do_open(dir, dentry, fmode, flags, sattr, cred, &res);
                if (status == 0)
                        break;
                /* NOTE: BAD_SEQID means the server and client disagree about the
                 * book-keeping w.r.t. state-changing operations
                 * (OPEN/CLOSE/LOCK/LOCKU...)
                 * It is actually a sign of a bug on the client or on the server.
                 *
                 * If we receive a BAD_SEQID error in the particular case of
                 * doing an OPEN, we assume that nfs_increment_open_seqid() will
                 * have unhashed the old state_owner for us, and that we can
                 * therefore safely retry using a new one. We should still warn
                 * the user though...
                 */
                if (status == -NFS4ERR_BAD_SEQID) {
                        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 (nfs4_copy_delegation_stateid(&arg.stateid, inode)) {
                /* Use that stateid */
        } else if (state != NULL) {
                nfs4_copy_stateid(&arg.stateid, state, current->files, current->tgid);
        } else
                memcpy(&arg.stateid, &zero_stateid, sizeof(arg.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_handle_exception(server,
                                _nfs4_do_setattr(inode, cred, fattr, sattr, state),
                                &exception);
        } while (exception.retry);
        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);

        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);
        }