Pull 5165 into release branch

[linux-2.6] / fs / nfs / nfs4proc.c

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

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

#include "nfs4_fs.h"
#include "delegation.h"

#define NFSDBG_FACILITY         NFSDBG_PROC

#define NFS4_POLL_RETRY_MIN     (1*HZ)
#define NFS4_POLL_RETRY_MAX     (15*HZ)

static int _nfs4_proc_open_confirm(struct rpc_clnt *clnt, const struct nfs_fh *fh, struct nfs4_state_owner *sp, nfs4_stateid *stateid, struct nfs_seqid *seqid);
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 *);
static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry);
static int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct nfs4_exception *exception);
extern u32 *nfs4_decode_dirent(u32 *p, struct nfs_entry *entry, int plus);
extern struct rpc_procinfo nfs4_procedures[];

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

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

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

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

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

static void nfs4_setup_readdir(u64 cookie, u32 *verifier, struct dentry *dentry,
                struct nfs4_readdir_arg *readdir)
{
        u32 *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 = (u32 *)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, dentry->d_inode->i_ino);
        }
        
        *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, dentry->d_parent->d_inode->i_ino);

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

static void
renew_lease(struct nfs_server *server, unsigned long timestamp)
{
        struct nfs4_client *clp = server->nfs4_state;
        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 update_changeattr(struct inode *inode, struct nfs4_change_info *cinfo)
{
        struct nfs_inode *nfsi = NFS_I(inode);

        spin_lock(&inode->i_lock);
        nfsi->cache_validity |= NFS_INO_INVALID_ATTR;
        if (cinfo->before == nfsi->change_attr && cinfo->atomic)
                nfsi->change_attr = cinfo->after;
        spin_unlock(&inode->i_lock);
}

/* Helper for asynchronous RPC calls */
static int nfs4_call_async(struct rpc_clnt *clnt, rpc_action tk_begin,
                rpc_action tk_exit, void *calldata)
{
        struct rpc_task *task;

        if (!(task = rpc_new_task(clnt, tk_exit, RPC_TASK_ASYNC)))
                return -ENOMEM;

        task->tk_calldata = calldata;
        task->tk_action = tk_begin;
        rpc_execute(task);
        return 0;
}

static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid, int open_flags)
{
        struct inode *inode = state->inode;

        open_flags &= (FMODE_READ|FMODE_WRITE);
        /* Protect against nfs4_find_state_byowner() */
        spin_lock(&state->owner->so_lock);
        spin_lock(&inode->i_lock);
        memcpy(&state->stateid, stateid, sizeof(state->stateid));
        if ((open_flags & FMODE_WRITE))
                state->nwriters++;
        if (open_flags & FMODE_READ)
                state->nreaders++;
        nfs4_state_set_mode_locked(state, state->state | open_flags);
        spin_unlock(&inode->i_lock);
        spin_unlock(&state->owner->so_lock);
}

/*
 * OPEN_RECLAIM:
 *      reclaim state on the server after a reboot.
 */
static int _nfs4_open_reclaim(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        struct inode *inode = state->inode;
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_delegation *delegation = NFS_I(inode)->delegation;
        struct nfs_openargs o_arg = {
                .fh = NFS_FH(inode),
                .id = sp->so_id,
                .open_flags = state->state,
                .clientid = server->nfs4_state->cl_clientid,
                .claim = NFS4_OPEN_CLAIM_PREVIOUS,
                .bitmask = server->attr_bitmask,
        };
        struct nfs_openres o_res = {
                .server = server,       /* Grrr */
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_OPEN_NOATTR],
                .rpc_argp       = &o_arg,
                .rpc_resp       = &o_res,
                .rpc_cred       = sp->so_cred,
        };
        int status;

        if (delegation != NULL) {
                if (!(delegation->flags & NFS_DELEGATION_NEED_RECLAIM)) {
                        memcpy(&state->stateid, &delegation->stateid,
                                        sizeof(state->stateid));
                        set_bit(NFS_DELEGATED_STATE, &state->flags);
                        return 0;
                }
                o_arg.u.delegation_type = delegation->type;
        }
        o_arg.seqid = nfs_alloc_seqid(&sp->so_seqid);
        if (o_arg.seqid == NULL)
                return -ENOMEM;
        status = rpc_call_sync(server->client, &msg, RPC_TASK_NOINTR);
        /* Confirm the sequence as being established */
        nfs_confirm_seqid(&sp->so_seqid, status);
        nfs_increment_open_seqid(status, o_arg.seqid);
        if (status == 0) {
                memcpy(&state->stateid, &o_res.stateid, sizeof(state->stateid));
                if (o_res.delegation_type != 0) {
                        nfs_inode_reclaim_delegation(inode, sp->so_cred, &o_res);
                        /* Did the server issue an immediate delegation recall? */
                        if (o_res.do_recall)
                                nfs_async_inode_return_delegation(inode, &o_res.stateid);
                }
        }
        nfs_free_seqid(o_arg.seqid);
        clear_bit(NFS_DELEGATED_STATE, &state->flags);
        /* Ensure we update the inode attributes */
        NFS_CACHEINV(inode);
        return status;
}

static int nfs4_open_reclaim(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_open_reclaim(sp, state);
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_open_delegation_recall(struct dentry *dentry, struct nfs4_state *state)
{
        struct nfs4_state_owner  *sp  = state->owner;
        struct inode *inode = dentry->d_inode;
        struct nfs_server *server = NFS_SERVER(inode);
        struct dentry *parent = dget_parent(dentry);
        struct nfs_openargs arg = {
                .fh = NFS_FH(parent->d_inode),
                .clientid = server->nfs4_state->cl_clientid,
                .name = &dentry->d_name,
                .id = sp->so_id,
                .server = server,
                .bitmask = server->attr_bitmask,
                .claim = NFS4_OPEN_CLAIM_DELEGATE_CUR,
        };
        struct nfs_openres res = {
                .server = server,
        };
        struct  rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_OPEN_NOATTR],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
                .rpc_cred       = sp->so_cred,
        };
        int status = 0;

        if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
                goto out;
        if (state->state == 0)
                goto out;
        arg.seqid = nfs_alloc_seqid(&sp->so_seqid);
        status = -ENOMEM;
        if (arg.seqid == NULL)
                goto out;
        arg.open_flags = state->state;
        memcpy(arg.u.delegation.data, state->stateid.data, sizeof(arg.u.delegation.data));
        status = rpc_call_sync(server->client, &msg, RPC_TASK_NOINTR);
        nfs_increment_open_seqid(status, arg.seqid);
        if (status != 0)
                goto out_free;
        if(res.rflags & NFS4_OPEN_RESULT_CONFIRM) {
                status = _nfs4_proc_open_confirm(server->client, NFS_FH(inode),
                                sp, &res.stateid, arg.seqid);
                if (status != 0)
                        goto out_free;
        }
        nfs_confirm_seqid(&sp->so_seqid, 0);
        if (status >= 0) {
                memcpy(state->stateid.data, res.stateid.data,
                                sizeof(state->stateid.data));
                clear_bit(NFS_DELEGATED_STATE, &state->flags);
        }
out_free:
        nfs_free_seqid(arg.seqid);
out:
        dput(parent);
        return status;
}

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

static int _nfs4_proc_open_confirm(struct rpc_clnt *clnt, const struct nfs_fh *fh, struct nfs4_state_owner *sp, nfs4_stateid *stateid, struct nfs_seqid *seqid)
{
        struct nfs_open_confirmargs arg = {
                .fh             = fh,
                .seqid          = seqid,
                .stateid        = *stateid,
        };
        struct nfs_open_confirmres res;
        struct  rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_OPEN_CONFIRM],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
                .rpc_cred       = sp->so_cred,
        };
        int status;

        status = rpc_call_sync(clnt, &msg, RPC_TASK_NOINTR);
        /* Confirm the sequence as being established */
        nfs_confirm_seqid(&sp->so_seqid, status);
        nfs_increment_open_seqid(status, seqid);
        if (status >= 0)
                memcpy(stateid, &res.stateid, sizeof(*stateid));
        return status;
}

static int _nfs4_proc_open(struct inode *dir, struct nfs4_state_owner  *sp, struct nfs_openargs *o_arg, struct nfs_openres *o_res)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN],
                .rpc_argp = o_arg,
                .rpc_resp = o_res,
                .rpc_cred = sp->so_cred,
        };
        int status;

        /* Update sequence id. The caller must serialize! */
        o_arg->id = sp->so_id;
        o_arg->clientid = sp->so_client->cl_clientid;

        status = rpc_call_sync(server->client, &msg, RPC_TASK_NOINTR);
        if (status == 0) {
                /* OPEN on anything except a regular file is disallowed in NFSv4 */
                switch (o_res->f_attr->mode & S_IFMT) {
                        case S_IFREG:
                                break;
                        case S_IFLNK:
                                status = -ELOOP;
                                break;
                        case S_IFDIR:
                                status = -EISDIR;
                                break;
                        default:
                                status = -ENOTDIR;
                }
        }

        nfs_increment_open_seqid(status, o_arg->seqid);
        if (status != 0)
                goto out;
        if (o_arg->open_flags & O_CREAT) {
                update_changeattr(dir, &o_res->cinfo);
                nfs_post_op_update_inode(dir, o_res->dir_attr);
        } else
                nfs_refresh_inode(dir, o_res->dir_attr);
        if(o_res->rflags & NFS4_OPEN_RESULT_CONFIRM) {
                status = _nfs4_proc_open_confirm(server->client, &o_res->fh,
                                sp, &o_res->stateid, o_arg->seqid);
                if (status != 0)
                        goto out;
        }
        nfs_confirm_seqid(&sp->so_seqid, 0);
        if (!(o_res->f_attr->valid & NFS_ATTR_FATTR))
                status = server->rpc_ops->getattr(server, &o_res->fh, o_res->f_attr);
out:
        return status;
}

static int _nfs4_do_access(struct inode *inode, struct rpc_cred *cred, int openflags)
{
        struct nfs_access_entry cache;
        int mask = 0;
        int status;

        if (openflags & FMODE_READ)
                mask |= MAY_READ;
        if (openflags & FMODE_WRITE)
                mask |= MAY_WRITE;
        status = nfs_access_get_cached(inode, cred, &cache);
        if (status == 0)
                goto out;

        /* Be clever: ask server to check for all possible rights */
        cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
        cache.cred = cred;
        cache.jiffies = jiffies;
        status = _nfs4_proc_access(inode, &cache);
        if (status != 0)
                return status;
        nfs_access_add_cache(inode, &cache);
out:
        if ((cache.mask & mask) == mask)
                return 0;
        return -EACCES;
}

/*
 * OPEN_EXPIRED:
 *      reclaim state on the server after a network partition.
 *      Assumes caller holds the appropriate lock
 */
static int _nfs4_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *state, struct dentry *dentry)
{
        struct dentry *parent = dget_parent(dentry);
        struct inode *dir = parent->d_inode;
        struct inode *inode = state->inode;
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_delegation *delegation = NFS_I(inode)->delegation;
        struct nfs_fattr f_attr, dir_attr;
        struct nfs_openargs o_arg = {
                .fh = NFS_FH(dir),
                .open_flags = state->state,
                .name = &dentry->d_name,
                .bitmask = server->attr_bitmask,
                .claim = NFS4_OPEN_CLAIM_NULL,
        };
        struct nfs_openres o_res = {
                .f_attr = &f_attr,
                .dir_attr = &dir_attr,
                .server = server,
        };
        int status = 0;

        if (delegation != NULL && !(delegation->flags & NFS_DELEGATION_NEED_RECLAIM)) {
                status = _nfs4_do_access(inode, sp->so_cred, state->state);
                if (status < 0)
                        goto out;
                memcpy(&state->stateid, &delegation->stateid, sizeof(state->stateid));
                set_bit(NFS_DELEGATED_STATE, &state->flags);
                goto out;
        }
        o_arg.seqid = nfs_alloc_seqid(&sp->so_seqid);
        status = -ENOMEM;
        if (o_arg.seqid == NULL)
                goto out;
        nfs_fattr_init(&f_attr);
        nfs_fattr_init(&dir_attr);
        status = _nfs4_proc_open(dir, sp, &o_arg, &o_res);
        if (status != 0)
                goto out_nodeleg;
        /* Check if files differ */
        if ((f_attr.mode & S_IFMT) != (inode->i_mode & S_IFMT))
                goto out_stale;
        /* Has the file handle changed? */
        if (nfs_compare_fh(&o_res.fh, NFS_FH(inode)) != 0) {
                /* Verify if the change attributes are the same */
                if (f_attr.change_attr != NFS_I(inode)->change_attr)
                        goto out_stale;
                if (nfs_size_to_loff_t(f_attr.size) != inode->i_size)
                        goto out_stale;
                /* Lets just pretend that this is the same file */
                nfs_copy_fh(NFS_FH(inode), &o_res.fh);
                NFS_I(inode)->fileid = f_attr.fileid;
        }
        memcpy(&state->stateid, &o_res.stateid, sizeof(state->stateid));
        if (o_res.delegation_type != 0) {
                if (!(delegation->flags & NFS_DELEGATION_NEED_RECLAIM))
                        nfs_inode_set_delegation(inode, sp->so_cred, &o_res);
                else
                        nfs_inode_reclaim_delegation(inode, sp->so_cred, &o_res);
        }
out_nodeleg:
        nfs_free_seqid(o_arg.seqid);
        clear_bit(NFS_DELEGATED_STATE, &state->flags);
out:
        dput(parent);
        return status;
out_stale:
        status = -ESTALE;
        /* Invalidate the state owner so we don't ever use it again */
        nfs4_drop_state_owner(sp);
        d_drop(dentry);
        /* Should we be trying to close that stateid? */
        goto out_nodeleg;
}

static inline int nfs4_do_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *state, struct dentry *dentry)
{
        struct nfs_server *server = NFS_SERVER(dentry->d_inode);
        struct nfs4_exception exception = { };
        int err;

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

static int nfs4_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        struct nfs_inode *nfsi = NFS_I(state->inode);
        struct nfs_open_context *ctx;
        int status;

        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);
                status = nfs4_do_open_expired(sp, state, ctx->dentry);
                put_nfs_open_context(ctx);
                return status;
        }
        spin_unlock(&state->inode->i_lock);
        return -ENOENT;
}

/*
 * Returns an nfs4_state + an extra reference to the inode
 */
static int _nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred *cred, struct nfs4_state **res)
{
        struct nfs_delegation *delegation;
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_client *clp = server->nfs4_state;
        struct nfs_inode *nfsi = NFS_I(inode);
        struct nfs4_state_owner *sp = NULL;
        struct nfs4_state *state = NULL;
        int open_flags = flags & (FMODE_READ|FMODE_WRITE);
        int err;

        /* Protect against reboot recovery - NOTE ORDER! */
        down_read(&clp->cl_sem);
        /* Protect against delegation recall */
        down_read(&nfsi->rwsem);
        delegation = NFS_I(inode)->delegation;
        err = -ENOENT;
        if (delegation == NULL || (delegation->type & open_flags) != open_flags)
                goto out_err;
        err = -ENOMEM;
        if (!(sp = nfs4_get_state_owner(server, cred))) {
                dprintk("%s: nfs4_get_state_owner failed!\n", __FUNCTION__);
                goto out_err;
        }
        state = nfs4_get_open_state(inode, sp);
        if (state == NULL)
                goto out_err;

        err = -ENOENT;
        if ((state->state & open_flags) == open_flags) {
                spin_lock(&inode->i_lock);
                if (open_flags & FMODE_READ)
                        state->nreaders++;
                if (open_flags & FMODE_WRITE)
                        state->nwriters++;
                spin_unlock(&inode->i_lock);
                goto out_ok;
        } else if (state->state != 0)
                goto out_err;

        lock_kernel();
        err = _nfs4_do_access(inode, cred, open_flags);
        unlock_kernel();
        if (err != 0)
                goto out_err;
        set_bit(NFS_DELEGATED_STATE, &state->flags);
        update_open_stateid(state, &delegation->stateid, open_flags);
out_ok:
        nfs4_put_state_owner(sp);
        up_read(&nfsi->rwsem);
        up_read(&clp->cl_sem);
        igrab(inode);
        *res = state;
        return 0; 
out_err:
        if (sp != NULL) {
                if (state != NULL)
                        nfs4_put_open_state(state);
                nfs4_put_state_owner(sp);
        }
        up_read(&nfsi->rwsem);
        up_read(&clp->cl_sem);
        if (err != -EACCES)
                nfs_inode_return_delegation(inode);
        return err;
}

static struct nfs4_state *nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred *cred)
{
        struct nfs4_exception exception = { };
        struct nfs4_state *res;
        int err;

        do {
                err = _nfs4_open_delegated(inode, flags, cred, &res);
                if (err == 0)
                        break;
                res = ERR_PTR(nfs4_handle_exception(NFS_SERVER(inode),
                                        err, &exception));
        } while (exception.retry);
        return res;
}

/*
 * Returns an nfs4_state + an referenced inode
 */
static int _nfs4_do_open(struct inode *dir, struct dentry *dentry, 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_client *clp = server->nfs4_state;
        struct inode *inode = NULL;
        int                     status;
        struct nfs_fattr f_attr, dir_attr;
        struct nfs_openargs o_arg = {
                .fh             = NFS_FH(dir),
                .open_flags     = flags,
                .name           = &dentry->d_name,
                .server         = server,
                .bitmask = server->attr_bitmask,
                .claim = NFS4_OPEN_CLAIM_NULL,
        };
        struct nfs_openres o_res = {
                .f_attr         = &f_attr,
                .dir_attr       = &dir_attr,
                .server         = server,
        };

        /* Protect against reboot recovery conflicts */
        down_read(&clp->cl_sem);
        status = -ENOMEM;
        if (!(sp = nfs4_get_state_owner(server, cred))) {
                dprintk("nfs4_do_open: nfs4_get_state_owner failed!\n");
                goto out_err;
        }
        if (flags & O_EXCL) {
                u32 *p = (u32 *) o_arg.u.verifier.data;
                p[0] = jiffies;
                p[1] = current->pid;
        } else
                o_arg.u.attrs = sattr;
        /* Serialization for the sequence id */

        o_arg.seqid = nfs_alloc_seqid(&sp->so_seqid);
        if (o_arg.seqid == NULL)
                return -ENOMEM;
        nfs_fattr_init(&f_attr);
        nfs_fattr_init(&dir_attr);
        status = _nfs4_proc_open(dir, sp, &o_arg, &o_res);
        if (status != 0)
                goto out_err;

        status = -ENOMEM;
        inode = nfs_fhget(dir->i_sb, &o_res.fh, &f_attr);
        if (!inode)
                goto out_err;
        state = nfs4_get_open_state(inode, sp);
        if (!state)
                goto out_err;
        update_open_stateid(state, &o_res.stateid, flags);
        if (o_res.delegation_type != 0)
                nfs_inode_set_delegation(inode, cred, &o_res);
        nfs_free_seqid(o_arg.seqid);
        nfs4_put_state_owner(sp);
        up_read(&clp->cl_sem);
        *res = state;
        return 0;
out_err:
        if (sp != NULL) {
                if (state != NULL)
                        nfs4_put_open_state(state);
                nfs_free_seqid(o_arg.seqid);
                nfs4_put_state_owner(sp);
        }
        /* Note: clp->cl_sem must be released before nfs4_put_open_state()! */
        up_read(&clp->cl_sem);
        if (inode != NULL)
                iput(inode);
        *res = NULL;
        return status;
}


static struct nfs4_state *nfs4_do_open(struct inode *dir, struct dentry *dentry, 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, flags, sattr, cred, &res);
                if (status == 0)
                        break;
                /* NOTE: BAD_SEQID means the server and client disagree about the
                 * book-keeping w.r.t. state-changing operations
                 * (OPEN/CLOSE/LOCK/LOCKU...)
                 * It is actually a sign of a bug on the client or on the server.
                 *
                 * If we receive a BAD_SEQID error in the particular case of
                 * doing an OPEN, we assume that nfs_increment_open_seqid() will
                 * have unhashed the old state_owner for us, and that we can
                 * therefore safely retry using a new one. We should still warn
                 * the user though...
                 */
                if (status == -NFS4ERR_BAD_SEQID) {
                        printk(KERN_WARNING "NFS: v4 server returned a bad sequence-id error!\n");
                        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;
                }
                res = ERR_PTR(nfs4_handle_exception(NFS_SERVER(dir),
                                        status, &exception));
        } while (exception.retry);
        return res;
}

static int _nfs4_do_setattr(struct nfs_server *server, struct nfs_fattr *fattr,
                struct nfs_fh *fhandle, struct iattr *sattr,
                struct nfs4_state *state)
{
        struct nfs_setattrargs  arg = {
                .fh             = fhandle,
                .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,
        };
        int status;

        nfs_fattr_init(fattr);

        if (state != NULL) {
                msg.rpc_cred = state->owner->so_cred;
                nfs4_copy_stateid(&arg.stateid, state, current->files);
        } else
                memcpy(&arg.stateid, &zero_stateid, sizeof(arg.stateid));

        status = rpc_call_sync(server->client, &msg, 0);
        return status;
}

static int nfs4_do_setattr(struct nfs_server *server, struct nfs_fattr *fattr,
                struct nfs_fh *fhandle, struct iattr *sattr,
                struct nfs4_state *state)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(server,
                                _nfs4_do_setattr(server, fattr, fhandle, 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;
};

static void nfs4_free_closedata(struct nfs4_closedata *calldata)
{
        struct nfs4_state *state = calldata->state;
        struct nfs4_state_owner *sp = state->owner;

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

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

        /* hmm. we are done with the inode, and in the process of freeing
         * the state_owner. we keep this around to process errors
         */
        nfs_increment_open_seqid(task->tk_status, calldata->arg.seqid);
        switch (task->tk_status) {
                case 0:
                        memcpy(&state->stateid, &calldata->res.stateid,
                                        sizeof(state->stateid));
                        break;
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_EXPIRED:
                        nfs4_schedule_state_recovery(server->nfs4_state);
                        break;
                default:
                        if (nfs4_async_handle_error(task, server) == -EAGAIN) {
                                rpc_restart_call(task);
                                return;
                        }
        }
        nfs_refresh_inode(calldata->inode, calldata->res.fattr);
        nfs4_free_closedata(calldata);
}

static void nfs4_close_begin(struct rpc_task *task)
{
        struct nfs4_closedata *calldata = (struct nfs4_closedata *)task->tk_calldata;
        struct nfs4_state *state = calldata->state;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE],
                .rpc_argp = &calldata->arg,
                .rpc_resp = &calldata->res,
                .rpc_cred = state->owner->so_cred,
        };
        int mode = 0, old_mode;
        int status;

        status = nfs_wait_on_sequence(calldata->arg.seqid, task);
        if (status != 0)
                return;
        /* Recalculate the new open mode in case someone reopened the file
         * while we were waiting in line to be scheduled.
         */
        spin_lock(&state->owner->so_lock);
        spin_lock(&calldata->inode->i_lock);
        mode = old_mode = state->state;
        if (state->nreaders == 0)
                mode &= ~FMODE_READ;
        if (state->nwriters == 0)
                mode &= ~FMODE_WRITE;
        nfs4_state_set_mode_locked(state, mode);
        spin_unlock(&calldata->inode->i_lock);
        spin_unlock(&state->owner->so_lock);
        if (mode == old_mode || test_bit(NFS_DELEGATED_STATE, &state->flags)) {
                nfs4_free_closedata(calldata);
                task->tk_exit = NULL;
                rpc_exit(task, 0);
                return;
        }
        nfs_fattr_init(calldata->res.fattr);
        if (mode != 0)
                msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
        calldata->arg.open_flags = mode;
        rpc_call_setup(task, &msg, 0);
}

/* 
 * 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 inode *inode, struct nfs4_state *state) 
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_closedata *calldata;
        int status = -ENOMEM;

        calldata = kmalloc(sizeof(*calldata), GFP_KERNEL);
        if (calldata == NULL)
                goto out;
        calldata->inode = inode;
        calldata->state = state;
        calldata->arg.fh = NFS_FH(inode);
        calldata->arg.stateid = &state->stateid;
        /* Serialization for the sequence id */
        calldata->arg.seqid = nfs_alloc_seqid(&state->owner->so_seqid);
        if (calldata->arg.seqid == NULL)
                goto out_free_calldata;
        calldata->arg.bitmask = server->attr_bitmask;
        calldata->res.fattr = &calldata->fattr;
        calldata->res.server = server;

        status = nfs4_call_async(server->client, nfs4_close_begin,
                        nfs4_close_done, calldata);
        if (status == 0)
                goto out;

        nfs_free_seqid(calldata->arg.seqid);
out_free_calldata:
        kfree(calldata);
out:
        return status;
}

static void nfs4_intent_set_file(struct nameidata *nd, struct dentry *dentry, struct nfs4_state *state)
{
        struct file *filp;

        filp = lookup_instantiate_filp(nd, dentry, NULL);
        if (!IS_ERR(filp)) {
                struct nfs_open_context *ctx;
                ctx = (struct nfs_open_context *)filp->private_data;
                ctx->state = state;
        } else
                nfs4_close_state(state, nd->intent.open.flags);
}

struct dentry *
nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
        struct iattr attr;
        struct rpc_cred *cred;
        struct nfs4_state *state;
        struct dentry *res;

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

        cred = rpcauth_lookupcred(NFS_SERVER(dir)->client->cl_auth, 0);
        if (IS_ERR(cred))
                return (struct dentry *)cred;
        state = nfs4_do_open(dir, dentry, nd->intent.open.flags, &attr, cred);
        put_rpccred(cred);
        if (IS_ERR(state)) {
                if (PTR_ERR(state) == -ENOENT)
                        d_add(dentry, NULL);
                return (struct dentry *)state;
        }
        res = d_add_unique(dentry, state->inode);
        if (res != NULL)
                dentry = res;
        nfs4_intent_set_file(nd, dentry, state);
        return res;
}

int
nfs4_open_revalidate(struct inode *dir, struct dentry *dentry, int openflags, struct nameidata *nd)
{
        struct rpc_cred *cred;
        struct nfs4_state *state;
        struct inode *inode;

        cred = rpcauth_lookupcred(NFS_SERVER(dir)->client->cl_auth, 0);
        if (IS_ERR(cred))
                return PTR_ERR(cred);
        state = nfs4_open_delegated(dentry->d_inode, openflags, cred);
        if (IS_ERR(state))
                state = nfs4_do_open(dir, dentry, openflags, NULL, cred);
        put_rpccred(cred);
        if (IS_ERR(state)) {
                switch (PTR_ERR(state)) {
                        case -EPERM:
                        case -EACCES:
                        case -EDQUOT:
                        case -ENOSPC:
                        case -EROFS:
                                lookup_instantiate_filp(nd, (struct dentry *)state, NULL);
                                return 1;
                        case -ENOENT:
                                if (dentry->d_inode == NULL)
                                        return 1;
                }
                goto out_drop;
        }
        inode = state->inode;
        iput(inode);
        if (inode == dentry->d_inode) {
                nfs4_intent_set_file(nd, dentry, state);
                return 1;
        }
        nfs4_close_state(state, openflags);
out_drop:
        d_drop(dentry);
        return 0;
}


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

        status = rpc_call_sync(server->client, &msg, 0);
        if (status == 0) {
                memcpy(server->attr_bitmask, res.attr_bitmask, sizeof(server->attr_bitmask));
                if (res.attr_bitmask[0] & FATTR4_WORD0_ACL)
                        server->caps |= NFS_CAP_ACLS;
                if (res.has_links != 0)
                        server->caps |= NFS_CAP_HARDLINKS;
                if (res.has_symlinks != 0)
                        server->caps |= NFS_CAP_SYMLINKS;
                server->acl_bitmask = res.acl_bitmask;
        }
        return status;
}

static 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 rpc_call_sync(server->client, &msg, 0);
}

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

static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_fsinfo *info)
{
        struct nfs_fattr *      fattr = info->fattr;
        unsigned char *         p;
        struct qstr             q;
        struct nfs4_lookup_arg args = {
                .dir_fh = fhandle,
                .name = &q,
                .bitmask = nfs4_fattr_bitmap,
        };
        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,
        };
        int status;

        /*
         * Now we do a separate LOOKUP for each component of the mount path.
         * The LOOKUPs are done separately so that we can conveniently
         * catch an ERR_WRONGSEC if it occurs along the way...
         */
        status = nfs4_lookup_root(server, fhandle, info);
        if (status)
                goto out;

        p = server->mnt_path;
        for (;;) {
                struct nfs4_exception exception = { };

                while (*p == '/')
                        p++;
                if (!*p)
                        break;
                q.name = p;
                while (*p && (*p != '/'))
                        p++;
                q.len = p - q.name;

                do {
                        nfs_fattr_init(fattr);
                        status = nfs4_handle_exception(server,
                                        rpc_call_sync(server->client, &msg, 0),
                                        &exception);
                } while (exception.retry);
                if (status == 0)
                        continue;
                if (status == -ENOENT) {
                        printk(KERN_NOTICE "NFS: mount path %s does not exist!\n", server->mnt_path);
                        printk(KERN_NOTICE "NFS: suggestion: try mounting '/' instead.\n");
                }
                break;
        }
        if (status == 0)
                status = nfs4_server_capabilities(server, fhandle);
        if (status == 0)
                status = nfs4_do_fsinfo(server, fhandle, info);
out:
        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 rpc_call_sync(server->client, &msg, 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 rpc_cred *cred;
        struct inode *inode = dentry->d_inode;
        struct nfs_open_context *ctx;
        struct nfs4_state *state = NULL;
        int status;

        nfs_fattr_init(fattr);
        
        cred = rpcauth_lookupcred(NFS_SERVER(inode)->client->cl_auth, 0);
        if (IS_ERR(cred))
                return PTR_ERR(cred);

        /* Search for an existing open(O_WRITE) file */
        ctx = nfs_find_open_context(inode, cred, FMODE_WRITE);
        if (ctx != NULL)
                state = ctx->state;

        status = nfs4_do_setattr(NFS_SERVER(inode), fattr,
                        NFS_FH(inode), sattr, state);
        if (status == 0)
                nfs_setattr_update_inode(inode, sattr);
        if (ctx != NULL)
                put_nfs_open_context(ctx);
        put_rpccred(cred);
        return status;
}

static int _nfs4_proc_lookup(struct inode *dir, struct qstr *name,
                struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
        int                    status;
        struct nfs_server *server = NFS_SERVER(dir);
        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 = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
        dprintk("NFS reply lookup: %d\n", status);
        return status;
}

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

static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry)
{
        struct nfs4_accessargs args = {
                .fh = NFS_FH(inode),
        };
        struct nfs4_accessres res = { 0 };
        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;
        }
        status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
        if (!status) {
                entry->mask = 0;
                if (res.access & NFS4_ACCESS_READ)
                        entry->mask |= MAY_READ;
                if (res.access & (NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE))
                        entry->mask |= MAY_WRITE;
                if (res.access & (NFS4_ACCESS_LOOKUP|NFS4_ACCESS_EXECUTE))
                        entry->mask |= MAY_EXEC;
        }
        return status;
}

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

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

        return rpc_call_sync(NFS_CLIENT(inode), &msg, 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;
}

static int _nfs4_proc_read(struct nfs_read_data *rdata)
{
        int flags = rdata->flags;
        struct inode *inode = rdata->inode;
        struct nfs_fattr *fattr = rdata->res.fattr;
        struct nfs_server *server = NFS_SERVER(inode);
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_READ],
                .rpc_argp       = &rdata->args,
                .rpc_resp       = &rdata->res,
                .rpc_cred       = rdata->cred,
        };
        unsigned long timestamp = jiffies;
        int status;

        dprintk("NFS call  read %d @ %Ld\n", rdata->args.count,
                        (long long) rdata->args.offset);

        nfs_fattr_init(fattr);
        status = rpc_call_sync(server->client, &msg, flags);
        if (!status)
                renew_lease(server, timestamp);
        dprintk("NFS reply read: %d\n", status);
        return status;
}

static int nfs4_proc_read(struct nfs_read_data *rdata)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(rdata->inode),
                                _nfs4_proc_read(rdata),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_write(struct nfs_write_data *wdata)
{
        int rpcflags = wdata->flags;
        struct inode *inode = wdata->inode;
        struct nfs_fattr *fattr = wdata->res.fattr;
        struct nfs_server *server = NFS_SERVER(inode);
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_WRITE],
                .rpc_argp       = &wdata->args,
                .rpc_resp       = &wdata->res,
                .rpc_cred       = wdata->cred,
        };
        int status;

        dprintk("NFS call  write %d @ %Ld\n", wdata->args.count,
                        (long long) wdata->args.offset);

        wdata->args.bitmask = server->attr_bitmask;
        wdata->res.server = server;
        nfs_fattr_init(fattr);
        status = rpc_call_sync(server->client, &msg, rpcflags);
        dprintk("NFS reply write: %d\n", status);
        if (status < 0)
                return status;
        nfs_post_op_update_inode(inode, fattr);
        return wdata->res.count;
}

static int nfs4_proc_write(struct nfs_write_data *wdata)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(wdata->inode),
                                _nfs4_proc_write(wdata),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_commit(struct nfs_write_data *cdata)
{
        struct inode *inode = cdata->inode;
        struct nfs_fattr *fattr = cdata->res.fattr;
        struct nfs_server *server = NFS_SERVER(inode);
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_COMMIT],
                .rpc_argp       = &cdata->args,
                .rpc_resp       = &cdata->res,
                .rpc_cred       = cdata->cred,
        };
        int status;

        dprintk("NFS call  commit %d @ %Ld\n", cdata->args.count,
                        (long long) cdata->args.offset);

        cdata->args.bitmask = server->attr_bitmask;
        cdata->res.server = server;
        nfs_fattr_init(fattr);
        status = rpc_call_sync(server->client, &msg, 0);
        dprintk("NFS reply commit: %d\n", status);
        if (status >= 0)
                nfs_post_op_update_inode(inode, fattr);
        return status;
}

static int nfs4_proc_commit(struct nfs_write_data *cdata)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(cdata->inode),
                                _nfs4_proc_commit(cdata),
                                &exception);
        } while (exception.retry);
        return err;
}

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

static int
nfs4_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
                 int flags, struct nameidata *nd)
{
        struct nfs4_state *state;
        struct rpc_cred *cred;
        int status = 0;

        cred = rpcauth_lookupcred(NFS_SERVER(dir)->client->cl_auth, 0);
        if (IS_ERR(cred)) {
                status = PTR_ERR(cred);
                goto out;
        }
        state = nfs4_do_open(dir, dentry, flags, sattr, cred);
        put_rpccred(cred);
        if (IS_ERR(state)) {
                status = PTR_ERR(state);
                goto out;
        }
        d_instantiate(dentry, state->inode);
        if (flags & O_EXCL) {
                struct nfs_fattr fattr;
                status = nfs4_do_setattr(NFS_SERVER(dir), &fattr,
                                     NFS_FH(state->inode), sattr, state);
                if (status == 0)
                        nfs_setattr_update_inode(state->inode, sattr);
        }
        if (status == 0 && nd != NULL && (nd->flags & LOOKUP_OPEN))
                nfs4_intent_set_file(nd, dentry, state);
        else
                nfs4_close_state(state, flags);
out:
        return status;
}

static int _nfs4_proc_remove(struct inode *dir, struct qstr *name)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs4_remove_arg args = {
                .fh = NFS_FH(dir),
                .name = name,
                .bitmask = server->attr_bitmask,
        };
        struct nfs_fattr dir_attr;
        struct nfs4_remove_res  res = {
                .server = server,
                .dir_attr = &dir_attr,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_REMOVE],
                .rpc_argp       = &args,
                .rpc_resp       = &res,
        };
        int                     status;

        nfs_fattr_init(res.dir_attr);
        status = rpc_call_sync(server->client, &msg, 0);
        if (status == 0) {
                update_changeattr(dir, &res.cinfo);
                nfs_post_op_update_inode(dir, res.dir_attr);
        }
        return status;
}

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

struct unlink_desc {
        struct nfs4_remove_arg  args;
        struct nfs4_remove_res  res;
        struct nfs_fattr dir_attr;
};

static int nfs4_proc_unlink_setup(struct rpc_message *msg, struct dentry *dir,
                struct qstr *name)
{
        struct nfs_server *server = NFS_SERVER(dir->d_inode);
        struct unlink_desc *up;

        up = (struct unlink_desc *) kmalloc(sizeof(*up), GFP_KERNEL);
        if (!up)
                return -ENOMEM;
        
        up->args.fh = NFS_FH(dir->d_inode);
        up->args.name = name;
        up->args.bitmask = server->attr_bitmask;
        up->res.server = server;
        up->res.dir_attr = &up->dir_attr;
        
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_REMOVE];
        msg->rpc_argp = &up->args;
        msg->rpc_resp = &up->res;
        return 0;
}

static int nfs4_proc_unlink_done(struct dentry *dir, struct rpc_task *task)
{
        struct rpc_message *msg = &task->tk_msg;
        struct unlink_desc *up;
        
        if (msg->rpc_resp != NULL) {
                up = container_of(msg->rpc_resp, struct unlink_desc, res);
                update_changeattr(dir->d_inode, &up->res.cinfo);
                nfs_post_op_update_inode(dir->d_inode, up->res.dir_attr);
                kfree(up);
                msg->rpc_resp = NULL;
                msg->rpc_argp = NULL;
        }
        return 0;
}

static int _nfs4_proc_rename(struct inode *old_dir, struct qstr *old_name,
                struct inode *new_dir, struct qstr *new_name)
{
        struct nfs_server *server = NFS_SERVER(old_dir);
        struct nfs4_rename_arg arg = {
                .old_dir = NFS_FH(old_dir),
                .new_dir = NFS_FH(new_dir),
                .old_name = old_name,
                .new_name = new_name,
                .bitmask = server->attr_bitmask,
        };
        struct nfs_fattr old_fattr, new_fattr;
        struct nfs4_rename_res res = {
                .server = server,
                .old_fattr = &old_fattr,
                .new_fattr = &new_fattr,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RENAME],
                .rpc_argp = &arg,
                .rpc_resp = &res,
        };
        int                     status;
        
        nfs_fattr_init(res.old_fattr);
        nfs_fattr_init(res.new_fattr);
        status = rpc_call_sync(server->client, &msg, 0);

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

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

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

        nfs_fattr_init(res.fattr);
        nfs_fattr_init(res.dir_attr);
        status = rpc_call_sync(server->client, &msg, 0);
        if (!status) {
                update_changeattr(dir, &res.cinfo);
                nfs_post_op_update_inode(dir, res.dir_attr);
                nfs_refresh_inode(inode, res.fattr);
        }

        return status;
}

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

static int _nfs4_proc_symlink(struct inode *dir, struct qstr *name,
                struct qstr *path, struct iattr *sattr, struct nfs_fh *fhandle,
                struct nfs_fattr *fattr)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_fattr dir_fattr;
        struct nfs4_create_arg arg = {
                .dir_fh = NFS_FH(dir),
                .server = server,
                .name = name,
                .attrs = sattr,
                .ftype = NF4LNK,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_create_res res = {
                .server = server,
                .fh = fhandle,
                .fattr = fattr,
                .dir_fattr = &dir_fattr,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SYMLINK],
                .rpc_argp = &arg,
                .rpc_resp = &res,
        };
        int                     status;

        if (path->len > NFS4_MAXPATHLEN)
                return -ENAMETOOLONG;
        arg.u.symlink = path;
        nfs_fattr_init(fattr);
        nfs_fattr_init(&dir_fattr);
        
        status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
        if (!status)
                update_changeattr(dir, &res.dir_cinfo);
        nfs_post_op_update_inode(dir, res.dir_fattr);
        return status;
}

static int nfs4_proc_symlink(struct inode *dir, struct qstr *name,
                struct qstr *path, struct iattr *sattr, struct nfs_fh *fhandle,
                struct nfs_fattr *fattr)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dir),
                                _nfs4_proc_symlink(dir, name, path, sattr,
                                        fhandle, fattr),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_fh fhandle;
        struct nfs_fattr fattr, dir_fattr;
        struct nfs4_create_arg arg = {
                .dir_fh = NFS_FH(dir),
                .server = server,
                .name = &dentry->d_name,
                .attrs = sattr,
                .ftype = NF4DIR,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_create_res res = {
                .server = server,
                .fh = &fhandle,
                .fattr = &fattr,
                .dir_fattr = &dir_fattr,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CREATE],
                .rpc_argp = &arg,
                .rpc_resp = &res,
        };
        int                     status;

        nfs_fattr_init(&fattr);
        nfs_fattr_init(&dir_fattr);
        
        status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
        if (!status) {
                update_changeattr(dir, &res.dir_cinfo);
                nfs_post_op_update_inode(dir, res.dir_fattr);
                status = nfs_instantiate(dentry, &fhandle, &fattr);
        }
        return status;
}

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

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

        dprintk("%s: dentry = %s/%s, cookie = %Lu\n", __FUNCTION__,
                        dentry->d_parent->d_name.name,
                        dentry->d_name.name,
                        (unsigned long long)cookie);
        lock_kernel();
        nfs4_setup_readdir(cookie, NFS_COOKIEVERF(dir), dentry, &args);
        res.pgbase = args.pgbase;
        status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
        if (status == 0)
                memcpy(NFS_COOKIEVERF(dir), res.verifier.data, NFS4_VERIFIER_SIZE);
        unlock_kernel();
        dprintk("%s: returns %d\n", __FUNCTION__, status);
        return status;
}

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

static int _nfs4_proc_mknod(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr, dev_t rdev)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_fh fh;
        struct nfs_fattr fattr, dir_fattr;
        struct nfs4_create_arg arg = {
                .dir_fh = NFS_FH(dir),
                .server = server,
                .name = &dentry->d_name,
                .attrs = sattr,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_create_res res = {
                .server = server,
                .fh = &fh,
                .fattr = &fattr,
                .dir_fattr = &dir_fattr,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CREATE],
                .rpc_argp = &arg,
                .rpc_resp = &res,
        };
        int                     status;
        int                     mode = sattr->ia_mode;

        nfs_fattr_init(&fattr);
        nfs_fattr_init(&dir_fattr);

        BUG_ON(!(sattr->ia_valid & ATTR_MODE));
        BUG_ON(!S_ISFIFO(mode) && !S_ISBLK(mode) && !S_ISCHR(mode) && !S_ISSOCK(mode));
        if (S_ISFIFO(mode))
                arg.ftype = NF4FIFO;
        else if (S_ISBLK(mode)) {
                arg.ftype = NF4BLK;
                arg.u.device.specdata1 = MAJOR(rdev);
                arg.u.device.specdata2 = MINOR(rdev);
        }
        else if (S_ISCHR(mode)) {
                arg.ftype = NF4CHR;
                arg.u.device.specdata1 = MAJOR(rdev);
                arg.u.device.specdata2 = MINOR(rdev);
        }
        else
                arg.ftype = NF4SOCK;
        
        status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
        if (status == 0) {
                update_changeattr(dir, &res.dir_cinfo);
                nfs_post_op_update_inode(dir, res.dir_fattr);
                status = nfs_instantiate(dentry, &fh, &fattr);
        }
        return status;
}

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

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

        nfs_fattr_init(fsstat->fattr);
        return rpc_call_sync(server->client, &msg, 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 rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_FSINFO],
                .rpc_argp = &args,
                .rpc_resp = fsinfo,
        };

        return rpc_call_sync(server->client, &msg, 0);
}

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

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

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

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

        /* 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 rpc_call_sync(server->client, &msg, 0);
}

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

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

static void
nfs4_read_done(struct rpc_task *task)
{
        struct nfs_read_data *data = (struct nfs_read_data *) task->tk_calldata;
        struct inode *inode = data->inode;

        if (nfs4_async_handle_error(task, NFS_SERVER(inode)) == -EAGAIN) {
                rpc_restart_call(task);
                return;
        }
        if (task->tk_status > 0)
                renew_lease(NFS_SERVER(inode), data->timestamp);
        /* Call back common NFS readpage processing */
        nfs_readpage_result(task);
}

static void
nfs4_proc_read_setup(struct nfs_read_data *data)
{
        struct rpc_task *task = &data->task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ],
                .rpc_argp = &data->args,
                .rpc_resp = &data->res,
                .rpc_cred = data->cred,
        };
        struct inode *inode = data->inode;
        int flags;

        data->timestamp   = jiffies;

        /* N.B. Do we need to test? Never called for swapfile inode */
        flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);

        /* Finalize the task. */
        rpc_init_task(task, NFS_CLIENT(inode), nfs4_read_done, flags);
        rpc_call_setup(task, &msg, 0);
}

static void
nfs4_write_done(struct rpc_task *task)
{
        struct nfs_write_data *data = (struct nfs_write_data *) task->tk_calldata;
        struct inode *inode = data->inode;
        
        if (nfs4_async_handle_error(task, NFS_SERVER(inode)) == -EAGAIN) {
                rpc_restart_call(task);
                return;
        }
        if (task->tk_status >= 0) {
                renew_lease(NFS_SERVER(inode), data->timestamp);
                nfs_post_op_update_inode(inode, data->res.fattr);
        }
        /* Call back common NFS writeback processing */
        nfs_writeback_done(task);
}

static void
nfs4_proc_write_setup(struct nfs_write_data *data, int how)
{
        struct rpc_task *task = &data->task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_WRITE],
                .rpc_argp = &data->args,
                .rpc_resp = &data->res,
                .rpc_cred = data->cred,
        };
        struct inode *inode = data->inode;
        struct nfs_server *server = NFS_SERVER(inode);
        int stable;
        int flags;
        
        if (how & FLUSH_STABLE) {
                if (!NFS_I(inode)->ncommit)
                        stable = NFS_FILE_SYNC;
                else
                        stable = NFS_DATA_SYNC;
        } else
                stable = NFS_UNSTABLE;
        data->args.stable = stable;
        data->args.bitmask = server->attr_bitmask;
        data->res.server = server;

        data->timestamp   = jiffies;

        /* Set the initial flags for the task.  */
        flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;

        /* Finalize the task. */
        rpc_init_task(task, NFS_CLIENT(inode), nfs4_write_done, flags);
        rpc_call_setup(task, &msg, 0);
}

static void
nfs4_commit_done(struct rpc_task *task)
{
        struct nfs_write_data *data = (struct nfs_write_data *) task->tk_calldata;
        struct inode *inode = data->inode;
        
        if (nfs4_async_handle_error(task, NFS_SERVER(inode)) == -EAGAIN) {
                rpc_restart_call(task);
                return;
        }
        if (task->tk_status >= 0)
                nfs_post_op_update_inode(inode, data->res.fattr);
        /* Call back common NFS writeback processing */
        nfs_commit_done(task);
}

static void
nfs4_proc_commit_setup(struct nfs_write_data *data, int how)
{
        struct rpc_task *task = &data->task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_COMMIT],
                .rpc_argp = &data->args,
                .rpc_resp = &data->res,
                .rpc_cred = data->cred,
        };      
        struct inode *inode = data->inode;
        struct nfs_server *server = NFS_SERVER(inode);
        int flags;
        
        data->args.bitmask = server->attr_bitmask;
        data->res.server = server;

        /* Set the initial flags for the task.  */
        flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;

        /* Finalize the task. */
        rpc_init_task(task, NFS_CLIENT(inode), nfs4_commit_done, flags);
        rpc_call_setup(task, &msg, 0);  
}

/*
 * 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
renew_done(struct rpc_task *task)
{
        struct nfs4_client *clp = (struct nfs4_client *)task->tk_msg.rpc_argp;
        unsigned long timestamp = (unsigned long)task->tk_calldata;

        if (task->tk_status < 0) {
                switch (task->tk_status) {
                        case -NFS4ERR_STALE_CLIENTID:
                        case -NFS4ERR_EXPIRED:
                        case -NFS4ERR_CB_PATH_DOWN:
                                nfs4_schedule_state_recovery(clp);
                }
                return;
        }
        spin_lock(&clp->cl_lock);
        if (time_before(clp->cl_last_renewal,timestamp))
                clp->cl_last_renewal = timestamp;
        spin_unlock(&clp->cl_lock);
}

int
nfs4_proc_async_renew(struct nfs4_client *clp)
{
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_RENEW],
                .rpc_argp       = clp,
                .rpc_cred       = clp->cl_cred,
        };

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

int
nfs4_proc_renew(struct nfs4_client *clp)
{
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_RENEW],
                .rpc_argp       = clp,
                .rpc_cred       = clp->cl_cred,
        };
        unsigned long now = jiffies;
        int status;

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

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

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

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

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

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

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

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

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

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

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

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

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

static inline ssize_t nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t buflen)
{
        struct page *pages[NFS4ACL_MAXPAGES];
        struct nfs_getaclargs args = {
                .fh = NFS_FH(inode),
                .acl_pages = pages,
                .acl_len = buflen,
        };
        size_t resp_len = buflen;
        void *resp_buf;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETACL],
                .rpc_argp = &args,
                .rpc_resp = &resp_len,
        };
        struct page *localpage = NULL;
        int ret;

        if (buflen < PAGE_SIZE) {
                /* As long as we're doing a round trip to the server anyway,
                 * let's be prepared for a page of acl data. */
                localpage = alloc_page(GFP_KERNEL);
                resp_buf = page_address(localpage);
                if (localpage == NULL)
                        return -ENOMEM;
                args.acl_pages[0] = localpage;
                args.acl_pgbase = 0;
                resp_len = args.acl_len = PAGE_SIZE;
        } else {
                resp_buf = buf;
                buf_to_pages(buf, buflen, args.acl_pages, &args.acl_pgbase);
        }
        ret = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
        if (ret)
                goto out_free;
        if (resp_len > args.acl_len)
                nfs4_write_cached_acl(inode, NULL, resp_len);
        else
                nfs4_write_cached_acl(inode, resp_buf, resp_len);
        if (buf) {
                ret = -ERANGE;
                if (resp_len > buflen)
                        goto out_free;
                if (localpage)
                        memcpy(buf, resp_buf, resp_len);
        }
        ret = resp_len;
out_free:
        if (localpage)
                __free_page(localpage);
        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;
        ret = nfs4_read_cached_acl(inode, buf, buflen);
        if (ret != -ENOENT)
                return ret;
        return nfs4_get_acl_uncached(inode, buf, buflen);
}

static int nfs4_proc_set_acl(struct inode *inode, const void *buf, size_t buflen)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct page *pages[NFS4ACL_MAXPAGES];
        struct nfs_setaclargs arg = {
                .fh             = NFS_FH(inode),
                .acl_pages      = pages,
                .acl_len        = buflen,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_SETACL],
                .rpc_argp       = &arg,
                .rpc_resp       = NULL,
        };
        int ret;

        if (!nfs4_server_supports_acls(server))
                return -EOPNOTSUPP;
        nfs_inode_return_delegation(inode);
        buf_to_pages(buf, buflen, arg.acl_pages, &arg.acl_pgbase);
        ret = rpc_call_sync(NFS_SERVER(inode)->client, &msg, 0);
        if (ret == 0)
                nfs4_write_cached_acl(inode, buf, buflen);
        return ret;
}

static int
nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server)
{
        struct nfs4_client *clp = server->nfs4_state;

        if (!clp || task->tk_status >= 0)
                return 0;
        switch(task->tk_status) {
                case -NFS4ERR_STALE_CLIENTID:
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_EXPIRED:
                        rpc_sleep_on(&clp->cl_rpcwaitq, task, NULL, NULL);
                        nfs4_schedule_state_recovery(clp);
                        if (test_bit(NFS4CLNT_OK, &clp->cl_state))
                                rpc_wake_up_task(task);
                        task->tk_status = 0;
                        return -EAGAIN;
                case -NFS4ERR_GRACE:
                case -NFS4ERR_DELAY:
                        rpc_delay(task, NFS4_POLL_RETRY_MAX);
                        task->tk_status = 0;
                        return -EAGAIN;
                case -NFS4ERR_OLD_STATEID:
                        task->tk_status = 0;
                        return -EAGAIN;
        }
        task->tk_status = nfs4_map_errors(task->tk_status);
        return 0;
}

static int nfs4_wait_clnt_recover(struct rpc_clnt *clnt, struct nfs4_client *clp)
{
        DEFINE_WAIT(wait);
        sigset_t oldset;
        int interruptible, res = 0;

        might_sleep();

        rpc_clnt_sigmask(clnt, &oldset);
        interruptible = TASK_UNINTERRUPTIBLE;
        if (clnt->cl_intr)
                interruptible = TASK_INTERRUPTIBLE;
        prepare_to_wait(&clp->cl_waitq, &wait, interruptible);
        nfs4_schedule_state_recovery(clp);
        if (clnt->cl_intr && signalled())
                res = -ERESTARTSYS;
        else if (!test_bit(NFS4CLNT_OK, &clp->cl_state))
                schedule();
        finish_wait(&clp->cl_waitq, &wait);
        rpc_clnt_sigunmask(clnt, &oldset);
        return res;
}

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

        might_sleep();

        if (*timeout <= 0)
                *timeout = NFS4_POLL_RETRY_MIN;
        if (*timeout > NFS4_POLL_RETRY_MAX)
                *timeout = NFS4_POLL_RETRY_MAX;
        rpc_clnt_sigmask(clnt, &oldset);
        if (clnt->cl_intr) {
                schedule_timeout_interruptible(*timeout);
                if (signalled())
                        res = -ERESTARTSYS;
        } else
                schedule_timeout_uninterruptible(*timeout);
        rpc_clnt_sigunmask(clnt, &oldset);
        *timeout <<= 1;
        return res;
}

/* This is the error handling routine for processes that are allowed
 * to sleep.
 */
int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
{
        struct nfs4_client *clp = server->nfs4_state;
        int ret = errorcode;

        exception->retry = 0;
        switch(errorcode) {
                case 0:
                        return 0;
                case -NFS4ERR_STALE_CLIENTID:
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_EXPIRED:
                        ret = nfs4_wait_clnt_recover(server->client, clp);
                        if (ret == 0)
                                exception->retry = 1;
                        break;
                case -NFS4ERR_GRACE:
                case -NFS4ERR_DELAY:
                        ret = nfs4_delay(server->client, &exception->timeout);
                        if (ret != 0)
                                break;
                case -NFS4ERR_OLD_STATEID:
                        exception->retry = 1;
        }
        /* We failed to handle the error */
        return nfs4_map_errors(ret);
}

int nfs4_proc_setclientid(struct nfs4_client *clp, u32 program, unsigned short port)
{
        nfs4_verifier sc_verifier;
        struct nfs4_setclientid setclientid = {
                .sc_verifier = &sc_verifier,
                .sc_prog = program,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SETCLIENTID],
                .rpc_argp = &setclientid,
                .rpc_resp = clp,
                .rpc_cred = clp->cl_cred,
        };
        u32 *p;
        int loop = 0;
        int status;

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

        for(;;) {
                setclientid.sc_name_len = scnprintf(setclientid.sc_name,
                                sizeof(setclientid.sc_name), "%s/%u.%u.%u.%u %s %u",
                                clp->cl_ipaddr, NIPQUAD(clp->cl_addr.s_addr),
                                clp->cl_cred->cr_ops->cr_name,
                                clp->cl_id_uniquifier);
                setclientid.sc_netid_len = scnprintf(setclientid.sc_netid,
                                sizeof(setclientid.sc_netid), "tcp");
                setclientid.sc_uaddr_len = scnprintf(setclientid.sc_uaddr,
                                sizeof(setclientid.sc_uaddr), "%s.%d.%d",
                                clp->cl_ipaddr, port >> 8, port & 255);

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

int
nfs4_proc_setclientid_confirm(struct nfs4_client *clp)
{
        struct nfs_fsinfo fsinfo;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SETCLIENTID_CONFIRM],
                .rpc_argp = clp,
                .rpc_resp = &fsinfo,
                .rpc_cred = clp->cl_cred,
        };
        unsigned long now;
        int status;

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

static int _nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid)
{
        struct nfs4_delegreturnargs args = {
                .fhandle = NFS_FH(inode),
                .stateid = stateid,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DELEGRETURN],
                .rpc_argp = &args,
                .rpc_cred = cred,
        };

        return rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
}

int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_delegreturn(inode, cred, stateid);
                switch (err) {
                        case -NFS4ERR_STALE_STATEID:
                        case -NFS4ERR_EXPIRED:
                                nfs4_schedule_state_recovery(server->nfs4_state);
                        case 0:
                                return 0;
                }
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

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

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

static inline int
nfs4_lck_type(int cmd, struct file_lock *request)
{
        /* set lock type */
        switch (request->fl_type) {
                case F_RDLCK:
                        return IS_SETLKW(cmd) ? NFS4_READW_LT : NFS4_READ_LT;
                case F_WRLCK:
                        return IS_SETLKW(cmd) ? NFS4_WRITEW_LT : NFS4_WRITE_LT;
                case F_UNLCK:
                        return NFS4_WRITE_LT; 
        }
        BUG();
        return 0;
}

static inline uint64_t
nfs4_lck_length(struct file_lock *request)
{
        if (request->fl_end == OFFSET_MAX)
                return ~(uint64_t)0;
        return request->fl_end - request->fl_start + 1;
}

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 nfs4_client *clp = server->nfs4_state;
        struct nfs_lockargs arg = {
                .fh = NFS_FH(inode),
                .type = nfs4_lck_type(cmd, request),
                .offset = request->fl_start,
                .length = nfs4_lck_length(request),
        };
        struct nfs_lockres res = {
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_LOCKT],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
                .rpc_cred       = state->owner->so_cred,
        };
        struct nfs_lowner nlo;
        struct nfs4_lock_state *lsp;
        int status;

        down_read(&clp->cl_sem);
        nlo.clientid = clp->cl_clientid;
        status = nfs4_set_lock_state(state, request);
        if (status != 0)
                goto out;
        lsp = request->fl_u.nfs4_fl.owner;
        nlo.id = lsp->ls_id; 
        arg.u.lockt = &nlo;
        status = rpc_call_sync(server->client, &msg, 0);
        if (!status) {
                request->fl_type = F_UNLCK;
        } else if (status == -NFS4ERR_DENIED) {
                int64_t len, start, end;
                start = res.u.denied.offset;
                len = res.u.denied.length;
                end = start + len - 1;
                if (end < 0 || len == 0)
                        request->fl_end = OFFSET_MAX;
                else
                        request->fl_end = (loff_t)end;
                request->fl_start = (loff_t)start;
                request->fl_type = F_WRLCK;
                if (res.u.denied.type & 1)
                        request->fl_type = F_RDLCK;
                request->fl_pid = 0;
                status = 0;
        }
out:
        up_read(&clp->cl_sem);
        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();
        }
        if (res < 0)
                printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
                                __FUNCTION__);
        return res;
}

struct nfs4_unlockdata {
        struct nfs_lockargs arg;
        struct nfs_locku_opargs luargs;
        struct nfs_lockres res;
        struct nfs4_lock_state *lsp;
        struct nfs_open_context *ctx;
        atomic_t refcount;
        struct completion completion;
};

static void nfs4_locku_release_calldata(struct nfs4_unlockdata *calldata)
{
        if (atomic_dec_and_test(&calldata->refcount)) {
                nfs_free_seqid(calldata->luargs.seqid);
                nfs4_put_lock_state(calldata->lsp);
                put_nfs_open_context(calldata->ctx);
                kfree(calldata);
        }
}

static void nfs4_locku_complete(struct nfs4_unlockdata *calldata)
{
        complete(&calldata->completion);
        nfs4_locku_release_calldata(calldata);
}

static void nfs4_locku_done(struct rpc_task *task)
{
        struct nfs4_unlockdata *calldata = (struct nfs4_unlockdata *)task->tk_calldata;

        nfs_increment_lock_seqid(task->tk_status, calldata->luargs.seqid);
        switch (task->tk_status) {
                case 0:
                        memcpy(calldata->lsp->ls_stateid.data,
                                        calldata->res.u.stateid.data,
                                        sizeof(calldata->lsp->ls_stateid.data));
                        break;
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_EXPIRED:
                        nfs4_schedule_state_recovery(calldata->res.server->nfs4_state);
                        break;
                default:
                        if (nfs4_async_handle_error(task, calldata->res.server) == -EAGAIN) {
                                rpc_restart_call(task);
                                return;
                        }
        }
        nfs4_locku_complete(calldata);
}

static void nfs4_locku_begin(struct rpc_task *task)
{
        struct nfs4_unlockdata *calldata = (struct nfs4_unlockdata *)task->tk_calldata;
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_LOCKU],
                .rpc_argp       = &calldata->arg,
                .rpc_resp       = &calldata->res,
                .rpc_cred       = calldata->lsp->ls_state->owner->so_cred,
        };
        int status;

        status = nfs_wait_on_sequence(calldata->luargs.seqid, task);
        if (status != 0)
                return;
        if ((calldata->lsp->ls_flags & NFS_LOCK_INITIALIZED) == 0) {
                nfs4_locku_complete(calldata);
                task->tk_exit = NULL;
                rpc_exit(task, 0);
                return;
        }
        rpc_call_setup(task, &msg, 0);
}

static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs4_unlockdata *calldata;
        struct inode *inode = state->inode;
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_lock_state *lsp;
        int status;

        /* Is this a delegated lock? */
        if (test_bit(NFS_DELEGATED_STATE, &state->flags))
                return do_vfs_lock(request->fl_file, request);

        status = nfs4_set_lock_state(state, request);
        if (status != 0)
                return status;
        lsp = request->fl_u.nfs4_fl.owner;
        /* We might have lost the locks! */
        if ((lsp->ls_flags & NFS_LOCK_INITIALIZED) == 0)
                return 0;
        calldata = kmalloc(sizeof(*calldata), GFP_KERNEL);
        if (calldata == NULL)
                return -ENOMEM;
        calldata->luargs.seqid = nfs_alloc_seqid(&lsp->ls_seqid);
        if (calldata->luargs.seqid == NULL) {
                kfree(calldata);
                return -ENOMEM;
        }
        calldata->luargs.stateid = &lsp->ls_stateid;
        calldata->arg.fh = NFS_FH(inode);
        calldata->arg.type = nfs4_lck_type(cmd, request);
        calldata->arg.offset = request->fl_start;
        calldata->arg.length = nfs4_lck_length(request);
        calldata->arg.u.locku = &calldata->luargs;
        calldata->res.server = server;
        calldata->lsp = lsp;
        atomic_inc(&lsp->ls_count);

        /* Ensure we don't close file until we're done freeing locks! */
        calldata->ctx = get_nfs_open_context((struct nfs_open_context*)request->fl_file->private_data);

        atomic_set(&calldata->refcount, 2);
        init_completion(&calldata->completion);

        status = nfs4_call_async(NFS_SERVER(inode)->client, nfs4_locku_begin,
                        nfs4_locku_done, calldata);
        if (status == 0)
                wait_for_completion_interruptible(&calldata->completion);
        do_vfs_lock(request->fl_file, request);
        nfs4_locku_release_calldata(calldata);
        return status;
}

static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *request, int reclaim)
{
        struct inode *inode = state->inode;
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_lock_state *lsp = request->fl_u.nfs4_fl.owner;
        struct nfs_lock_opargs largs = {
                .lock_stateid = &lsp->ls_stateid,
                .open_stateid = &state->stateid,
                .lock_owner = {
                        .clientid = server->nfs4_state->cl_clientid,
                        .id = lsp->ls_id,
                },
                .reclaim = reclaim,
        };
        struct nfs_lockargs arg = {
                .fh = NFS_FH(inode),
                .type = nfs4_lck_type(cmd, request),
                .offset = request->fl_start,
                .length = nfs4_lck_length(request),
                .u = {
                        .lock = &largs,
                },
        };
        struct nfs_lockres res = {
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_LOCK],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
                .rpc_cred       = state->owner->so_cred,
        };
        int status = -ENOMEM;

        largs.lock_seqid = nfs_alloc_seqid(&lsp->ls_seqid);
        if (largs.lock_seqid == NULL)
                return -ENOMEM;
        if (!(lsp->ls_seqid.flags & NFS_SEQID_CONFIRMED)) {
                struct nfs4_state_owner *owner = state->owner;

                largs.open_seqid = nfs_alloc_seqid(&owner->so_seqid);
                if (largs.open_seqid == NULL)
                        goto out;
                largs.new_lock_owner = 1;
                status = rpc_call_sync(server->client, &msg, RPC_TASK_NOINTR);
                /* increment open seqid on success, and seqid mutating errors */
                if (largs.new_lock_owner != 0) {
                        nfs_increment_open_seqid(status, largs.open_seqid);
                        if (status == 0)
                                nfs_confirm_seqid(&lsp->ls_seqid, 0);
                }
                nfs_free_seqid(largs.open_seqid);
        } else
                status = rpc_call_sync(server->client, &msg, RPC_TASK_NOINTR);
        /* increment lock seqid on success, and seqid mutating errors*/
        nfs_increment_lock_seqid(status, largs.lock_seqid);
        /* save the returned stateid. */
        if (status == 0) {
                memcpy(lsp->ls_stateid.data, res.u.stateid.data,
                                sizeof(lsp->ls_stateid.data));
                lsp->ls_flags |= NFS_LOCK_INITIALIZED;
        } else if (status == -NFS4ERR_DENIED)
                status = -EAGAIN;
out:
        nfs_free_seqid(largs.lock_seqid);
        return status;
}

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

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

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

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

static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs4_client *clp = state->owner->so_client;
        int status;

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

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

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

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

        /* verify open state */
        ctx = (struct nfs_open_context *)filp->private_data;
        state = ctx->state;

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

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

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

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

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

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

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

#define XATTR_NAME_NFSV4_ACL "system.nfs4_acl"

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

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

        if (!S_ISREG(inode->i_mode) &&
            (!S_ISDIR(inode->i_mode) || inode->i_mode & S_ISVTX))
                return -EPERM;

        return nfs4_proc_set_acl(inode, buf, buflen);
}

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

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

        return nfs4_proc_get_acl(inode, buf, buflen);
}

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

        if (buf && buflen < len)
                return -ERANGE;
        if (buf)
                memcpy(buf, XATTR_NAME_NFSV4_ACL, len);
        return len;
}

struct nfs4_state_recovery_ops nfs4_reboot_recovery_ops = {
        .recover_open   = nfs4_open_reclaim,
        .recover_lock   = nfs4_lock_reclaim,
};

struct nfs4_state_recovery_ops nfs4_network_partition_recovery_ops = {
        .recover_open   = nfs4_open_expired,
        .recover_lock   = nfs4_lock_expired,
};

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

struct nfs_rpc_ops      nfs_v4_clientops = {
        .version        = 4,                    /* protocol version */
        .dentry_ops     = &nfs4_dentry_operations,
        .dir_inode_ops  = &nfs4_dir_inode_operations,
        .file_inode_ops = &nfs4_file_inode_operations,
        .getroot        = nfs4_proc_get_root,
        .getattr        = nfs4_proc_getattr,
        .setattr        = nfs4_proc_setattr,
        .lookup         = nfs4_proc_lookup,
        .access         = nfs4_proc_access,
        .readlink       = nfs4_proc_readlink,
        .read           = nfs4_proc_read,
        .write          = nfs4_proc_write,
        .commit         = nfs4_proc_commit,
        .create         = nfs4_proc_create,
        .remove         = nfs4_proc_remove,
        .unlink_setup   = nfs4_proc_unlink_setup,
        .unlink_done    = nfs4_proc_unlink_done,
        .rename         = nfs4_proc_rename,
        .link           = nfs4_proc_link,
        .symlink        = nfs4_proc_symlink,
        .mkdir          = nfs4_proc_mkdir,
        .rmdir          = nfs4_proc_remove,
        .readdir        = nfs4_proc_readdir,
        .mknod          = nfs4_proc_mknod,
        .statfs         = nfs4_proc_statfs,
        .fsinfo         = nfs4_proc_fsinfo,
        .pathconf       = nfs4_proc_pathconf,
        .decode_dirent  = nfs4_decode_dirent,
        .read_setup     = nfs4_proc_read_setup,
        .write_setup    = nfs4_proc_write_setup,
        .commit_setup   = nfs4_proc_commit_setup,
        .file_open      = nfs_open,
        .file_release   = nfs_release,
        .lock           = nfs4_proc_lock,
        .clear_acl_cache = nfs4_zap_acl_attr,
};

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