/*
 *  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"
#include "iostat.h"

#define NFSDBG_FACILITY         NFSDBG_PROC

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

struct nfs4_opendata;
static int _nfs4_proc_open(struct nfs4_opendata *data);
static int nfs4_do_fsinfo(struct nfs_server *, struct nfs_fh *, struct nfs_fsinfo *);
static int nfs4_async_handle_error(struct rpc_task *, const struct nfs_server *);
static int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct nfs4_exception *exception);
static int nfs4_wait_clnt_recover(struct rpc_clnt *clnt, struct nfs_client *clp);
static int _nfs4_proc_lookup(struct inode *dir, const struct qstr *name, struct nfs_fh *fhandle, struct nfs_fattr *fattr);
static int _nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fattr *fattr);

/* Prevent leaks of NFSv4 errors into userland */
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
};

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

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

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

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

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

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

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

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

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


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

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

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

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

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

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

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

        rpc_clnt_sigmask(task->tk_client, &oldset);
        ret = rpc_wait_for_completion_task(task);
        rpc_clnt_sigunmask(task->tk_client, &oldset);
        return ret;
}

static int can_open_cached(struct nfs4_state *state, int mode)
{
        int ret = 0;
        switch (mode & (FMODE_READ|FMODE_WRITE|O_EXCL)) {
                case FMODE_READ:
                        ret |= test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0;
                        break;
                case FMODE_WRITE:
                        ret |= test_bit(NFS_O_WRONLY_STATE, &state->flags) != 0;
                        break;
                case FMODE_READ|FMODE_WRITE:
                        ret |= test_bit(NFS_O_RDWR_STATE, &state->flags) != 0;
        }
        return ret;
}

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

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

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

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

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

static void nfs4_return_incompatible_delegation(struct inode *inode, mode_t open_flags)
{
        struct nfs_delegation *delegation;

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

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

        rcu_read_lock();
        delegation = rcu_dereference(nfsi->delegation);
        for (;;) {
                if (can_open_cached(state, open_mode)) {
                        spin_lock(&state->owner->so_lock);
                        if (can_open_cached(state, open_mode)) {
                                update_open_stateflags(state, open_mode);
                                spin_unlock(&state->owner->so_lock);
                                rcu_read_unlock();
                                goto out_return_state;
                        }
                        spin_unlock(&state->owner->so_lock);
                }
                if (delegation == NULL)
                        break;
                if (!can_open_delegated(delegation, open_mode))
                        break;
                /* Save the delegation */
                memcpy(stateid.data, delegation->stateid.data, sizeof(stateid.data));
                rcu_read_unlock();
                lock_kernel();
                ret = nfs_may_open(state->inode, state->owner->so_cred, open_mode);
                unlock_kernel();
                if (ret != 0)
                        goto out;
                ret = -EAGAIN;
                rcu_read_lock();
                delegation = rcu_dereference(nfsi->delegation);
                /* If no delegation, try a cached open */
                if (delegation == NULL)
                        continue;
                /* Is the delegation still valid? */
                if (memcmp(stateid.data, delegation->stateid.data, sizeof(stateid.data)) != 0)
                        continue;
                rcu_read_unlock();
                update_open_stateid(state, NULL, &stateid, open_mode);
                goto out_return_state;
        }
        rcu_read_unlock();
out:
        return ERR_PTR(ret);
out_return_state:
        atomic_inc(&state->count);
        return state;
}

static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
{
        struct inode *inode;
        struct nfs4_state *state = NULL;
        struct nfs_delegation *delegation;
        nfs4_stateid *deleg_stateid = NULL;
        int ret;

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

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

                rcu_read_lock();
                delegation = rcu_dereference(NFS_I(inode)->delegation);
                if (delegation)
                        delegation_flags = delegation->flags;
                rcu_read_unlock();
                if (!(delegation_flags & NFS_DELEGATION_NEED_RECLAIM))
                        nfs_inode_set_delegation(state->inode,
                                        data->owner->so_cred,
                                        &data->o_res);
                else
                        nfs_inode_reclaim_delegation(state->inode,
                                        data->owner->so_cred,
                                        &data->o_res);
        }
        rcu_read_lock();
        delegation = rcu_dereference(NFS_I(inode)->delegation);
        if (delegation != NULL)
                deleg_stateid = &delegation->stateid;
        update_open_stateid(state, &data->o_res.stateid, deleg_stateid, data->o_arg.open_flags);
        rcu_read_unlock();
        iput(inode);
out:
        return state;
err_put_inode:
        iput(inode);
err:
        return ERR_PTR(ret);
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

static void nfs4_open_confirm_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_opendata *data = calldata;
        struct  rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_CONFIRM],
                .rpc_argp = &data->c_arg,
                .rpc_resp = &data->c_res,
                .rpc_cred = data->owner->so_cred,
        };
        data->timestamp = jiffies;
        rpc_call_setup(task, &msg, 0);
}

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

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

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

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

static const struct rpc_call_ops nfs4_open_confirm_ops = {
        .rpc_call_prepare = nfs4_open_confirm_prepare,
        .rpc_call_done = nfs4_open_confirm_done,
        .rpc_release = nfs4_open_confirm_release,
};

/*
 * Note: On error, nfs4_proc_open_confirm will free the struct nfs4_opendata
 */
static int _nfs4_proc_open_confirm(struct nfs4_opendata *data)
{
        struct nfs_server *server = NFS_SERVER(data->dir->d_inode);
        struct rpc_task *task;
        int status;

        kref_get(&data->kref);
        data->rpc_done = 0;
        data->rpc_status = 0;
        task = rpc_run_task(server->client, RPC_TASK_ASYNC, &nfs4_open_confirm_ops, data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = nfs4_wait_for_completion_rpc_task(task);
        if (status != 0) {
                data->cancelled = 1;
                smp_wmb();
        } else
                status = data->rpc_status;
        rpc_put_task(task);
        return status;
}

static void nfs4_open_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_opendata *data = calldata;
        struct nfs4_state_owner *sp = data->owner;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN],
                .rpc_argp = &data->o_arg,
                .rpc_resp = &data->o_res,
                .rpc_cred = sp->so_cred,
        };
        
        if (nfs_wait_on_sequence(data->o_arg.seqid, task) != 0)
                return;
        /*
         * Check if we still need to send an OPEN call, or if we can use
         * a delegation instead.
         */
        if (data->state != NULL) {
                struct nfs_delegation *delegation;

                if (can_open_cached(data->state, data->o_arg.open_flags & (FMODE_READ|FMODE_WRITE|O_EXCL)))
                        goto out_no_action;
                rcu_read_lock();
                delegation = rcu_dereference(NFS_I(data->state->inode)->delegation);
                if (delegation != NULL &&
                   (delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0) {
                        rcu_read_unlock();
                        goto out_no_action;
                }
                rcu_read_unlock();
        }
        /* Update sequence id. */
        data->o_arg.id = sp->so_owner_id.id;
        data->o_arg.clientid = sp->so_client->cl_clientid;
        if (data->o_arg.claim == NFS4_OPEN_CLAIM_PREVIOUS) {
                msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_NOATTR];
                nfs_copy_fh(&data->o_res.fh, data->o_arg.fh);
        }
        data->timestamp = jiffies;
        rpc_call_setup(task, &msg, 0);
        return;
out_no_action:
        task->tk_action = NULL;

}

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

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

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

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

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

/*
 * Note: On error, nfs4_proc_open will free the struct nfs4_opendata
 */
static int _nfs4_proc_open(struct nfs4_opendata *data)
{
        struct inode *dir = data->dir->d_inode;
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_openargs *o_arg = &data->o_arg;
        struct nfs_openres *o_res = &data->o_res;
        struct rpc_task *task;
        int status;

        kref_get(&data->kref);
        data->rpc_done = 0;
        data->rpc_status = 0;
        data->cancelled = 0;
        task = rpc_run_task(server->client, RPC_TASK_ASYNC, &nfs4_open_ops, data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = nfs4_wait_for_completion_rpc_task(task);
        if (status != 0) {
                data->cancelled = 1;
                smp_wmb();
        } else
                status = data->rpc_status;
        rpc_put_task(task);
        if (status != 0 || !data->rpc_done)
                return status;

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

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

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

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

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

        opendata = nfs4_open_recoverdata_alloc(ctx, state);
        if (IS_ERR(opendata))
                return PTR_ERR(opendata);
        ret = nfs4_open_recover(opendata, state);
        if (ret == -ESTALE) {
                /* Invalidate the state owner so we don't ever use it again */
                nfs4_drop_state_owner(state->owner);
                d_drop(ctx->path.dentry);
        }
        nfs4_opendata_put(opendata);
        return ret;
}

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

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

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

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

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

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

/*
 * Returns a referenced nfs4_state
 */
static int _nfs4_do_open(struct inode *dir, struct path *path, 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 nfs_client *clp = server->nfs_client;
        struct nfs4_opendata *opendata;
        int status;

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

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

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

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

        state = nfs4_opendata_to_nfs4_state(opendata);
        status = PTR_ERR(state);
        if (IS_ERR(state))
                goto err_opendata_put;
        nfs4_opendata_put(opendata);
        nfs4_put_state_owner(sp);
        up_read(&clp->cl_sem);
        *res = state;
        return 0;
err_opendata_put:
        nfs4_opendata_put(opendata);
err_release_rwsem:
        up_read(&clp->cl_sem);
err_put_state_owner:
        nfs4_put_state_owner(sp);
out_err:
        *res = NULL;
        return status;
}


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

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

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

        nfs_fattr_init(fattr);

        if (nfs4_copy_delegation_stateid(&arg.stateid, inode)) {
                /* Use that stateid */
        } else if (state != NULL) {
                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);
        if (status == 0 && state != NULL)
                renew_lease(server, timestamp);
        return status;
}

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

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

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

        nfs4_put_open_state(calldata->state);
        nfs_free_seqid(calldata->arg.seqid);
        nfs4_put_state_owner(sp);
        dput(calldata->path.dentry);
        mntput(calldata->path.mnt);
        kfree(calldata);
}

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

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

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

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

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

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

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

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

        task = rpc_run_task(server->client, RPC_TASK_ASYNC, &nfs4_close_ops, calldata);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = 0;
        if (wait)
                status = rpc_wait_for_completion_task(task);
        rpc_put_task(task);
        return status;
out_free_calldata:
        kfree(calldata);
out:
        nfs4_put_open_state(state);
        nfs4_put_state_owner(sp);
        return status;
}

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

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

struct dentry *
nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
        struct dentry *parent;
        struct path path = {
                .mnt = nd->mnt,
                .dentry = dentry,
        };
        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_CLIENT(dir)->cl_auth, 0);
        if (IS_ERR(cred))
                return (struct dentry *)cred;
        parent = dentry->d_parent;
        /* Protect against concurrent sillydeletes */
        nfs_block_sillyrename(parent);
        state = nfs4_do_open(dir, &path, nd->intent.open.flags, &attr, cred);
        put_rpccred(cred);
        if (IS_ERR(state)) {
                if (PTR_ERR(state) == -ENOENT) {
                        d_add(dentry, NULL);
                        nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
                }
                nfs_unblock_sillyrename(parent);
                return (struct dentry *)state;
        }
        res = d_add_unique(dentry, igrab(state->inode));
        if (res != NULL)
                path.dentry = res;
        nfs_set_verifier(path.dentry, nfs_save_change_attribute(dir));
        nfs_unblock_sillyrename(parent);
        nfs4_intent_set_file(nd, &path, state);
        return res;
}

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

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

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;
}

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

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

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

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

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

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

static int _nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
        struct nfs4_getattr_arg args = {
                .fh = fhandle,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_getattr_res res = {
                .fattr = fattr,
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETATTR],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        
        nfs_fattr_init(fattr);
        return 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_CLIENT(inode)->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(inode, fattr, 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_lookupfh(struct nfs_server *server, const struct nfs_fh *dirfh,
                const struct qstr *name, struct nfs_fh *fhandle,
                struct nfs_fattr *fattr)
{
        int                    status;
        struct nfs4_lookup_arg args = {
                .bitmask = server->attr_bitmask,
                .dir_fh = dirfh,
                .name = name,
        };
        struct nfs4_lookup_res res = {
                .server = server,
                .fattr = fattr,
                .fh = fhandle,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOOKUP],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        nfs_fattr_init(fattr);

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

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

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

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

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

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

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

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

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

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

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

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

        nfs_fattr_init(&res.dir_attr);
        status = 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;
}

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

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

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

        if (nfs4_async_handle_error(task, res->server) == -EAGAIN)
                return 0;
        update_changeattr(dir, &res->cinfo);
        nfs_post_op_update_inode(dir, &res->dir_attr);
        return 1;
}

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

        status = 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_post_op_update_inode(inode, res.fattr);
        }

        return status;
}

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

static int _nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
                struct page *page, unsigned int len, 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 = 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 (len > NFS4_MAXPATHLEN)
                return -ENAMETOOLONG;

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

static int _nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr)
{
        struct 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);
        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);

        nfs_invalidate_atime(dir);

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

        if (nfs4_async_handle_error(task, server) == -EAGAIN) {
                rpc_restart_call(task);
                return -EAGAIN;
        }

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

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

        data->timestamp   = jiffies;

        rpc_call_setup(&data->task, &msg, 0);
}

static int nfs4_write_done(struct rpc_task *task, struct nfs_write_data *data)
{
        struct inode *inode = data->inode;
        
        if (nfs4_async_handle_error(task, NFS_SERVER(inode)) == -EAGAIN) {
                rpc_restart_call(task);
                return -EAGAIN;
        }
        if (task->tk_status >= 0) {
                renew_lease(NFS_SERVER(inode), data->timestamp);
                nfs_post_op_update_inode_force_wcc(inode, data->res.fattr);
        }
        return 0;
}

static void nfs4_proc_write_setup(struct nfs_write_data *data, int how)
{
        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;
        
        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;

        /* Finalize the task. */
        rpc_call_setup(&data->task, &msg, 0);
}

static int nfs4_commit_done(struct rpc_task *task, struct nfs_write_data *data)
{
        struct inode *inode = data->inode;
        
        if (nfs4_async_handle_error(task, NFS_SERVER(inode)) == -EAGAIN) {
                rpc_restart_call(task);
                return -EAGAIN;
        }
        nfs_refresh_inode(inode, data->res.fattr);
        return 0;
}

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

        rpc_call_setup(&data->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 nfs4_renew_done(struct rpc_task *task, void *data)
{
        struct nfs_client *clp = (struct nfs_client *)task->tk_msg.rpc_argp;
        unsigned long timestamp = (unsigned long)data;

        if (task->tk_status < 0) {
                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);
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t buflen)
{
        struct page *pages[NFS4ACL_MAXPAGES];
        struct nfs_getaclargs args = {
                .fh = NFS_FH(inode),
                .acl_pages = pages,
                .acl_len = buflen,
        };
        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_get_acl_uncached(struct inode *inode, void *buf, size_t buflen)
{
        struct nfs4_exception exception = { };
        ssize_t ret;
        do {
                ret = __nfs4_get_acl_uncached(inode, buf, buflen);
                if (ret >= 0)
                        break;
                ret = nfs4_handle_exception(NFS_SERVER(inode), ret, &exception);
        } while (exception.retry);
        return ret;
}

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

        if (!nfs4_server_supports_acls(server))
                return -EOPNOTSUPP;
        ret = nfs_revalidate_inode(server, inode);
        if (ret < 0)
                return ret;
        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_CLIENT(inode), &msg, 0);
        nfs_zap_caches(inode);
        return ret;
}

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

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

        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_STATE_RECOVER, &clp->cl_state) == 0)
                                rpc_wake_up_task(task);
                        task->tk_status = 0;
                        return -EAGAIN;
                case -NFS4ERR_DELAY:
                        nfs_inc_server_stats((struct nfs_server *) server,
                                                NFSIOS_DELAY);
                case -NFS4ERR_GRACE:
                        rpc_delay(task, NFS4_POLL_RETRY_MAX);
                        task->tk_status = 0;
                        return -EAGAIN;
                case -NFS4ERR_OLD_STATEID:
                        task->tk_status = 0;
                        return -EAGAIN;
        }
        task->tk_status = nfs4_map_errors(task->tk_status);
        return 0;
}

static int nfs4_wait_bit_interruptible(void *word)
{
        if (signal_pending(current))
                return -ERESTARTSYS;
        schedule();
        return 0;
}

static int nfs4_wait_clnt_recover(struct rpc_clnt *clnt, struct nfs_client *clp)
{
        sigset_t oldset;
        int res;

        might_sleep();

        rwsem_acquire(&clp->cl_sem.dep_map, 0, 0, _RET_IP_);

        rpc_clnt_sigmask(clnt, &oldset);
        res = wait_on_bit(&clp->cl_state, NFS4CLNT_STATE_RECOVER,
                        nfs4_wait_bit_interruptible,
                        TASK_INTERRUPTIBLE);
        rpc_clnt_sigunmask(clnt, &oldset);

        rwsem_release(&clp->cl_sem.dep_map, 1, _RET_IP_);
        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.
 */
static int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
{
        struct nfs_client *clp = server->nfs_client;
        int ret = errorcode;

        exception->retry = 0;
        switch(errorcode) {
                case 0:
                        return 0;
                case -NFS4ERR_STALE_CLIENTID:
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_EXPIRED:
                        nfs4_schedule_state_recovery(clp);
                        ret = nfs4_wait_clnt_recover(server->client, clp);
                        if (ret == 0)
                                exception->retry = 1;
                        break;
                case -NFS4ERR_FILE_OPEN:
                case -NFS4ERR_GRACE:
                case -NFS4ERR_DELAY:
                        ret = nfs4_delay(server->client, &exception->timeout);
                        if (ret != 0)
                                break;
                case -NFS4ERR_OLD_STATEID:
                        exception->retry = 1;
        }
        /* We failed to handle the error */
        return nfs4_map_errors(ret);
}

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

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

        for(;;) {
                setclientid.sc_name_len = scnprintf(setclientid.sc_name,
                                sizeof(setclientid.sc_name), "%s/%u.%u.%u.%u %s %u",
                                clp->cl_ipaddr, NIPQUAD(clp->cl_addr.sin_addr),
                                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;
}

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

        now = jiffies;
        status = rpc_call_sync(clp->cl_rpcclient, &msg, 0);
        if (status == 0) {
                spin_lock(&clp->cl_lock);
                clp->cl_lease_time = fsinfo.lease_time * HZ;
                clp->cl_last_renewal = now;
                clear_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
                spin_unlock(&clp->cl_lock);
        }
        return status;
}

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

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

static void nfs4_delegreturn_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_delegreturndata *data = calldata;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DELEGRETURN],
                .rpc_argp = &data->args,
                .rpc_resp = &data->res,
                .rpc_cred = data->cred,
        };
        nfs_fattr_init(data->res.fattr);
        rpc_call_setup(task, &msg, 0);