Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / nfsd / nfs4proc.c

/*
 *  fs/nfsd/nfs4proc.c
 *
 *  Server-side procedures 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/param.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/file.h>

#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/cache.h>
#include <linux/nfs4.h>
#include <linux/nfsd/state.h>
#include <linux/nfsd/xdr4.h>
#include <linux/nfs4_acl.h>
#include <linux/sunrpc/gss_api.h>

#define NFSDDBG_FACILITY                NFSDDBG_PROC

static inline void
fh_dup2(struct svc_fh *dst, struct svc_fh *src)
{
        fh_put(dst);
        dget(src->fh_dentry);
        if (src->fh_export)
                cache_get(&src->fh_export->h);
        *dst = *src;
}

static __be32
do_open_permission(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open, int accmode)
{
        __be32 status;

        if (open->op_truncate &&
                !(open->op_share_access & NFS4_SHARE_ACCESS_WRITE))
                return nfserr_inval;

        if (open->op_share_access & NFS4_SHARE_ACCESS_READ)
                accmode |= NFSD_MAY_READ;
        if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
                accmode |= (NFSD_MAY_WRITE | NFSD_MAY_TRUNC);
        if (open->op_share_deny & NFS4_SHARE_DENY_WRITE)
                accmode |= NFSD_MAY_WRITE;

        status = fh_verify(rqstp, current_fh, S_IFREG, accmode);

        return status;
}

static __be32
do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
{
        struct svc_fh resfh;
        __be32 status;
        int created = 0;

        fh_init(&resfh, NFS4_FHSIZE);
        open->op_truncate = 0;

        if (open->op_create) {
                /*
                 * Note: create modes (UNCHECKED,GUARDED...) are the same
                 * in NFSv4 as in v3.
                 */
                status = nfsd_create_v3(rqstp, current_fh, open->op_fname.data,
                                        open->op_fname.len, &open->op_iattr,
                                        &resfh, open->op_createmode,
                                        (u32 *)open->op_verf.data,
                                        &open->op_truncate, &created);

                /* If we ever decide to use different attrs to store the
                 * verifier in nfsd_create_v3, then we'll need to change this
                 */
                if (open->op_createmode == NFS4_CREATE_EXCLUSIVE && status == 0)
                        open->op_bmval[1] |= (FATTR4_WORD1_TIME_ACCESS |
                                                FATTR4_WORD1_TIME_MODIFY);
        } else {
                status = nfsd_lookup(rqstp, current_fh,
                                     open->op_fname.data, open->op_fname.len, &resfh);
                fh_unlock(current_fh);
        }
        if (status)
                goto out;

        set_change_info(&open->op_cinfo, current_fh);

        /* set reply cache */
        fh_dup2(current_fh, &resfh);
        open->op_stateowner->so_replay.rp_openfh_len = resfh.fh_handle.fh_size;
        memcpy(open->op_stateowner->so_replay.rp_openfh,
                        &resfh.fh_handle.fh_base, resfh.fh_handle.fh_size);

        if (!created)
                status = do_open_permission(rqstp, current_fh, open,
                                            NFSD_MAY_NOP);

out:
        fh_put(&resfh);
        return status;
}

static __be32
do_open_fhandle(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
{
        __be32 status;

        /* Only reclaims from previously confirmed clients are valid */
        if ((status = nfs4_check_open_reclaim(&open->op_clientid)))
                return status;

        /* We don't know the target directory, and therefore can not
        * set the change info
        */

        memset(&open->op_cinfo, 0, sizeof(struct nfsd4_change_info));

        /* set replay cache */
        open->op_stateowner->so_replay.rp_openfh_len = current_fh->fh_handle.fh_size;
        memcpy(open->op_stateowner->so_replay.rp_openfh,
                &current_fh->fh_handle.fh_base,
                current_fh->fh_handle.fh_size);

        open->op_truncate = (open->op_iattr.ia_valid & ATTR_SIZE) &&
                (open->op_iattr.ia_size == 0);

        status = do_open_permission(rqstp, current_fh, open,
                                    NFSD_MAY_OWNER_OVERRIDE);

        return status;
}


static __be32
nfsd4_open(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           struct nfsd4_open *open)
{
        __be32 status;
        dprintk("NFSD: nfsd4_open filename %.*s op_stateowner %p\n",
                (int)open->op_fname.len, open->op_fname.data,
                open->op_stateowner);

        /* This check required by spec. */
        if (open->op_create && open->op_claim_type != NFS4_OPEN_CLAIM_NULL)
                return nfserr_inval;

        nfs4_lock_state();

        /* check seqid for replay. set nfs4_owner */
        status = nfsd4_process_open1(open);
        if (status == nfserr_replay_me) {
                struct nfs4_replay *rp = &open->op_stateowner->so_replay;
                fh_put(&cstate->current_fh);
                cstate->current_fh.fh_handle.fh_size = rp->rp_openfh_len;
                memcpy(&cstate->current_fh.fh_handle.fh_base, rp->rp_openfh,
                                rp->rp_openfh_len);
                status = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_NOP);
                if (status)
                        dprintk("nfsd4_open: replay failed"
                                " restoring previous filehandle\n");
                else
                        status = nfserr_replay_me;
        }
        if (status)
                goto out;

        /* Openowner is now set, so sequence id will get bumped.  Now we need
         * these checks before we do any creates: */
        status = nfserr_grace;
        if (nfs4_in_grace() && open->op_claim_type != NFS4_OPEN_CLAIM_PREVIOUS)
                goto out;
        status = nfserr_no_grace;
        if (!nfs4_in_grace() && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)
                goto out;

        switch (open->op_claim_type) {
                case NFS4_OPEN_CLAIM_DELEGATE_CUR:
                        status = nfserr_inval;
                        if (open->op_create)
                                goto out;
                        /* fall through */
                case NFS4_OPEN_CLAIM_NULL:
                        /*
                         * (1) set CURRENT_FH to the file being opened,
                         * creating it if necessary, (2) set open->op_cinfo,
                         * (3) set open->op_truncate if the file is to be
                         * truncated after opening, (4) do permission checking.
                         */
                        status = do_open_lookup(rqstp, &cstate->current_fh,
                                                open);
                        if (status)
                                goto out;
                        break;
                case NFS4_OPEN_CLAIM_PREVIOUS:
                        open->op_stateowner->so_confirmed = 1;
                        /*
                         * The CURRENT_FH is already set to the file being
                         * opened.  (1) set open->op_cinfo, (2) set
                         * open->op_truncate if the file is to be truncated
                         * after opening, (3) do permission checking.
                        */
                        status = do_open_fhandle(rqstp, &cstate->current_fh,
                                                 open);
                        if (status)
                                goto out;
                        break;
                case NFS4_OPEN_CLAIM_DELEGATE_PREV:
                        open->op_stateowner->so_confirmed = 1;
                        dprintk("NFSD: unsupported OPEN claim type %d\n",
                                open->op_claim_type);
                        status = nfserr_notsupp;
                        goto out;
                default:
                        dprintk("NFSD: Invalid OPEN claim type %d\n",
                                open->op_claim_type);
                        status = nfserr_inval;
                        goto out;
        }
        /*
         * nfsd4_process_open2() does the actual opening of the file.  If
         * successful, it (1) truncates the file if open->op_truncate was
         * set, (2) sets open->op_stateid, (3) sets open->op_delegation.
         */
        status = nfsd4_process_open2(rqstp, &cstate->current_fh, open);
out:
        if (open->op_stateowner) {
                nfs4_get_stateowner(open->op_stateowner);
                cstate->replay_owner = open->op_stateowner;
        }
        nfs4_unlock_state();
        return status;
}

/*
 * filehandle-manipulating ops.
 */
static __be32
nfsd4_getfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
            struct svc_fh **getfh)
{
        if (!cstate->current_fh.fh_dentry)
                return nfserr_nofilehandle;

        *getfh = &cstate->current_fh;
        return nfs_ok;
}

static __be32
nfsd4_putfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
            struct nfsd4_putfh *putfh)
{
        fh_put(&cstate->current_fh);
        cstate->current_fh.fh_handle.fh_size = putfh->pf_fhlen;
        memcpy(&cstate->current_fh.fh_handle.fh_base, putfh->pf_fhval,
               putfh->pf_fhlen);
        return fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_NOP);
}

static __be32
nfsd4_putrootfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                void *arg)
{
        __be32 status;

        fh_put(&cstate->current_fh);
        status = exp_pseudoroot(rqstp, &cstate->current_fh);
        return status;
}

static __be32
nfsd4_restorefh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                void *arg)
{
        if (!cstate->save_fh.fh_dentry)
                return nfserr_restorefh;

        fh_dup2(&cstate->current_fh, &cstate->save_fh);
        return nfs_ok;
}

static __be32
nfsd4_savefh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             void *arg)
{
        if (!cstate->current_fh.fh_dentry)
                return nfserr_nofilehandle;

        fh_dup2(&cstate->save_fh, &cstate->current_fh);
        return nfs_ok;
}

/*
 * misc nfsv4 ops
 */
static __be32
nfsd4_access(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             struct nfsd4_access *access)
{
        if (access->ac_req_access & ~NFS3_ACCESS_FULL)
                return nfserr_inval;

        access->ac_resp_access = access->ac_req_access;
        return nfsd_access(rqstp, &cstate->current_fh, &access->ac_resp_access,
                           &access->ac_supported);
}

static __be32
nfsd4_commit(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             struct nfsd4_commit *commit)
{
        __be32 status;

        u32 *p = (u32 *)commit->co_verf.data;
        *p++ = nfssvc_boot.tv_sec;
        *p++ = nfssvc_boot.tv_usec;

        status = nfsd_commit(rqstp, &cstate->current_fh, commit->co_offset,
                             commit->co_count);
        if (status == nfserr_symlink)
                status = nfserr_inval;
        return status;
}

static __be32
nfsd4_create(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             struct nfsd4_create *create)
{
        struct svc_fh resfh;
        __be32 status;
        dev_t rdev;

        fh_init(&resfh, NFS4_FHSIZE);

        status = fh_verify(rqstp, &cstate->current_fh, S_IFDIR,
                           NFSD_MAY_CREATE);
        if (status == nfserr_symlink)
                status = nfserr_notdir;
        if (status)
                return status;

        switch (create->cr_type) {
        case NF4LNK:
                /* ugh! we have to null-terminate the linktext, or
                 * vfs_symlink() will choke.  it is always safe to
                 * null-terminate by brute force, since at worst we
                 * will overwrite the first byte of the create namelen
                 * in the XDR buffer, which has already been extracted
                 * during XDR decode.
                 */
                create->cr_linkname[create->cr_linklen] = 0;

                status = nfsd_symlink(rqstp, &cstate->current_fh,
                                      create->cr_name, create->cr_namelen,
                                      create->cr_linkname, create->cr_linklen,
                                      &resfh, &create->cr_iattr);
                break;

        case NF4BLK:
                rdev = MKDEV(create->cr_specdata1, create->cr_specdata2);
                if (MAJOR(rdev) != create->cr_specdata1 ||
                    MINOR(rdev) != create->cr_specdata2)
                        return nfserr_inval;
                status = nfsd_create(rqstp, &cstate->current_fh,
                                     create->cr_name, create->cr_namelen,
                                     &create->cr_iattr, S_IFBLK, rdev, &resfh);
                break;

        case NF4CHR:
                rdev = MKDEV(create->cr_specdata1, create->cr_specdata2);
                if (MAJOR(rdev) != create->cr_specdata1 ||
                    MINOR(rdev) != create->cr_specdata2)
                        return nfserr_inval;
                status = nfsd_create(rqstp, &cstate->current_fh,
                                     create->cr_name, create->cr_namelen,
                                     &create->cr_iattr,S_IFCHR, rdev, &resfh);
                break;

        case NF4SOCK:
                status = nfsd_create(rqstp, &cstate->current_fh,
                                     create->cr_name, create->cr_namelen,
                                     &create->cr_iattr, S_IFSOCK, 0, &resfh);
                break;

        case NF4FIFO:
                status = nfsd_create(rqstp, &cstate->current_fh,
                                     create->cr_name, create->cr_namelen,
                                     &create->cr_iattr, S_IFIFO, 0, &resfh);
                break;

        case NF4DIR:
                create->cr_iattr.ia_valid &= ~ATTR_SIZE;
                status = nfsd_create(rqstp, &cstate->current_fh,
                                     create->cr_name, create->cr_namelen,
                                     &create->cr_iattr, S_IFDIR, 0, &resfh);
                break;

        default:
                status = nfserr_badtype;
        }

        if (!status) {
                fh_unlock(&cstate->current_fh);
                set_change_info(&create->cr_cinfo, &cstate->current_fh);
                fh_dup2(&cstate->current_fh, &resfh);
        }

        fh_put(&resfh);
        return status;
}

static __be32
nfsd4_getattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              struct nfsd4_getattr *getattr)
{
        __be32 status;

        status = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_NOP);
        if (status)
                return status;

        if (getattr->ga_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1)
                return nfserr_inval;

        getattr->ga_bmval[0] &= NFSD_SUPPORTED_ATTRS_WORD0;
        getattr->ga_bmval[1] &= NFSD_SUPPORTED_ATTRS_WORD1;

        getattr->ga_fhp = &cstate->current_fh;
        return nfs_ok;
}

static __be32
nfsd4_link(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           struct nfsd4_link *link)
{
        __be32 status = nfserr_nofilehandle;

        if (!cstate->save_fh.fh_dentry)
                return status;
        status = nfsd_link(rqstp, &cstate->current_fh,
                           link->li_name, link->li_namelen, &cstate->save_fh);
        if (!status)
                set_change_info(&link->li_cinfo, &cstate->current_fh);
        return status;
}

static __be32
nfsd4_lookupp(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              void *arg)
{
        struct svc_fh tmp_fh;
        __be32 ret;

        fh_init(&tmp_fh, NFS4_FHSIZE);
        ret = exp_pseudoroot(rqstp, &tmp_fh);
        if (ret)
                return ret;
        if (tmp_fh.fh_dentry == cstate->current_fh.fh_dentry) {
                fh_put(&tmp_fh);
                return nfserr_noent;
        }
        fh_put(&tmp_fh);
        return nfsd_lookup(rqstp, &cstate->current_fh,
                           "..", 2, &cstate->current_fh);
}

static __be32
nfsd4_lookup(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             struct nfsd4_lookup *lookup)
{
        return nfsd_lookup(rqstp, &cstate->current_fh,
                           lookup->lo_name, lookup->lo_len,
                           &cstate->current_fh);
}

static __be32
nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           struct nfsd4_read *read)
{
        __be32 status;

        /* no need to check permission - this will be done in nfsd_read() */

        read->rd_filp = NULL;
        if (read->rd_offset >= OFFSET_MAX)
                return nfserr_inval;

        nfs4_lock_state();
        /* check stateid */
        if ((status = nfs4_preprocess_stateid_op(&cstate->current_fh,
                                &read->rd_stateid,
                                CHECK_FH | RD_STATE, &read->rd_filp))) {
                dprintk("NFSD: nfsd4_read: couldn't process stateid!\n");
                goto out;
        }
        if (read->rd_filp)
                get_file(read->rd_filp);
        status = nfs_ok;
out:
        nfs4_unlock_state();
        read->rd_rqstp = rqstp;
        read->rd_fhp = &cstate->current_fh;
        return status;
}

static __be32
nfsd4_readdir(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              struct nfsd4_readdir *readdir)
{
        u64 cookie = readdir->rd_cookie;
        static const nfs4_verifier zeroverf;

        /* no need to check permission - this will be done in nfsd_readdir() */

        if (readdir->rd_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1)
                return nfserr_inval;

        readdir->rd_bmval[0] &= NFSD_SUPPORTED_ATTRS_WORD0;
        readdir->rd_bmval[1] &= NFSD_SUPPORTED_ATTRS_WORD1;

        if ((cookie > ~(u32)0) || (cookie == 1) || (cookie == 2) ||
            (cookie == 0 && memcmp(readdir->rd_verf.data, zeroverf.data, NFS4_VERIFIER_SIZE)))
                return nfserr_bad_cookie;

        readdir->rd_rqstp = rqstp;
        readdir->rd_fhp = &cstate->current_fh;
        return nfs_ok;
}

static __be32
nfsd4_readlink(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
               struct nfsd4_readlink *readlink)
{
        readlink->rl_rqstp = rqstp;
        readlink->rl_fhp = &cstate->current_fh;
        return nfs_ok;
}

static __be32
nfsd4_remove(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             struct nfsd4_remove *remove)
{
        __be32 status;

        if (nfs4_in_grace())
                return nfserr_grace;
        status = nfsd_unlink(rqstp, &cstate->current_fh, 0,
                             remove->rm_name, remove->rm_namelen);
        if (status == nfserr_symlink)
                return nfserr_notdir;
        if (!status) {
                fh_unlock(&cstate->current_fh);
                set_change_info(&remove->rm_cinfo, &cstate->current_fh);
        }
        return status;
}

static __be32
nfsd4_rename(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             struct nfsd4_rename *rename)
{
        __be32 status = nfserr_nofilehandle;

        if (!cstate->save_fh.fh_dentry)
                return status;
        if (nfs4_in_grace() && !(cstate->save_fh.fh_export->ex_flags
                                        & NFSEXP_NOSUBTREECHECK))
                return nfserr_grace;
        status = nfsd_rename(rqstp, &cstate->save_fh, rename->rn_sname,
                             rename->rn_snamelen, &cstate->current_fh,
                             rename->rn_tname, rename->rn_tnamelen);

        /* the underlying filesystem returns different error's than required
         * by NFSv4. both save_fh and current_fh have been verified.. */
        if (status == nfserr_isdir)
                status = nfserr_exist;
        else if ((status == nfserr_notdir) &&
                  (S_ISDIR(cstate->save_fh.fh_dentry->d_inode->i_mode) &&
                   S_ISDIR(cstate->current_fh.fh_dentry->d_inode->i_mode)))
                status = nfserr_exist;
        else if (status == nfserr_symlink)
                status = nfserr_notdir;

        if (!status) {
                set_change_info(&rename->rn_sinfo, &cstate->current_fh);
                set_change_info(&rename->rn_tinfo, &cstate->save_fh);
        }
        return status;
}

static __be32
nfsd4_secinfo(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              struct nfsd4_secinfo *secinfo)
{
        struct svc_fh resfh;
        struct svc_export *exp;
        struct dentry *dentry;
        __be32 err;

        fh_init(&resfh, NFS4_FHSIZE);
        err = nfsd_lookup_dentry(rqstp, &cstate->current_fh,
                                    secinfo->si_name, secinfo->si_namelen,
                                    &exp, &dentry);
        if (err)
                return err;
        if (dentry->d_inode == NULL) {
                exp_put(exp);
                err = nfserr_noent;
        } else
                secinfo->si_exp = exp;
        dput(dentry);
        return err;
}

static __be32
nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              struct nfsd4_setattr *setattr)
{
        __be32 status = nfs_ok;

        if (setattr->sa_iattr.ia_valid & ATTR_SIZE) {
                nfs4_lock_state();
                status = nfs4_preprocess_stateid_op(&cstate->current_fh,
                        &setattr->sa_stateid, CHECK_FH | WR_STATE, NULL);
                nfs4_unlock_state();
                if (status) {
                        dprintk("NFSD: nfsd4_setattr: couldn't process stateid!\n");
                        return status;
                }
        }
        status = mnt_want_write(cstate->current_fh.fh_export->ex_path.mnt);
        if (status)
                return status;
        status = nfs_ok;
        if (setattr->sa_acl != NULL)
                status = nfsd4_set_nfs4_acl(rqstp, &cstate->current_fh,
                                            setattr->sa_acl);
        if (status)
                goto out;
        status = nfsd_setattr(rqstp, &cstate->current_fh, &setattr->sa_iattr,
                                0, (time_t)0);
out:
        mnt_drop_write(cstate->current_fh.fh_export->ex_path.mnt);
        return status;
}

static __be32
nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
            struct nfsd4_write *write)
{
        stateid_t *stateid = &write->wr_stateid;
        struct file *filp = NULL;
        u32 *p;
        __be32 status = nfs_ok;

        /* no need to check permission - this will be done in nfsd_write() */

        if (write->wr_offset >= OFFSET_MAX)
                return nfserr_inval;

        nfs4_lock_state();
        status = nfs4_preprocess_stateid_op(&cstate->current_fh, stateid,
                                        CHECK_FH | WR_STATE, &filp);
        if (filp)
                get_file(filp);
        nfs4_unlock_state();

        if (status) {
                dprintk("NFSD: nfsd4_write: couldn't process stateid!\n");
                return status;
        }

        write->wr_bytes_written = write->wr_buflen;
        write->wr_how_written = write->wr_stable_how;
        p = (u32 *)write->wr_verifier.data;
        *p++ = nfssvc_boot.tv_sec;
        *p++ = nfssvc_boot.tv_usec;

        status =  nfsd_write(rqstp, &cstate->current_fh, filp,
                             write->wr_offset, rqstp->rq_vec, write->wr_vlen,
                             write->wr_buflen, &write->wr_how_written);
        if (filp)
                fput(filp);

        if (status == nfserr_symlink)
                status = nfserr_inval;
        return status;
}

/* This routine never returns NFS_OK!  If there are no other errors, it
 * will return NFSERR_SAME or NFSERR_NOT_SAME depending on whether the
 * attributes matched.  VERIFY is implemented by mapping NFSERR_SAME
 * to NFS_OK after the call; NVERIFY by mapping NFSERR_NOT_SAME to NFS_OK.
 */
static __be32
_nfsd4_verify(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             struct nfsd4_verify *verify)
{
        __be32 *buf, *p;
        int count;
        __be32 status;

        status = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_NOP);
        if (status)
                return status;

        if ((verify->ve_bmval[0] & ~NFSD_SUPPORTED_ATTRS_WORD0)
            || (verify->ve_bmval[1] & ~NFSD_SUPPORTED_ATTRS_WORD1))
                return nfserr_attrnotsupp;
        if ((verify->ve_bmval[0] & FATTR4_WORD0_RDATTR_ERROR)
            || (verify->ve_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1))
                return nfserr_inval;
        if (verify->ve_attrlen & 3)
                return nfserr_inval;

        /* count in words:
         *   bitmap_len(1) + bitmap(2) + attr_len(1) = 4
         */
        count = 4 + (verify->ve_attrlen >> 2);
        buf = kmalloc(count << 2, GFP_KERNEL);
        if (!buf)
                return nfserr_resource;

        status = nfsd4_encode_fattr(&cstate->current_fh,
                                    cstate->current_fh.fh_export,
                                    cstate->current_fh.fh_dentry, buf,
                                    &count, verify->ve_bmval,
                                    rqstp, 0);

        /* this means that nfsd4_encode_fattr() ran out of space */
        if (status == nfserr_resource && count == 0)
                status = nfserr_not_same;
        if (status)
                goto out_kfree;

        p = buf + 3;
        status = nfserr_not_same;
        if (ntohl(*p++) != verify->ve_attrlen)
                goto out_kfree;
        if (!memcmp(p, verify->ve_attrval, verify->ve_attrlen))
                status = nfserr_same;

out_kfree:
        kfree(buf);
        return status;
}

static __be32
nfsd4_nverify(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              struct nfsd4_verify *verify)
{
        __be32 status;

        status = _nfsd4_verify(rqstp, cstate, verify);
        return status == nfserr_not_same ? nfs_ok : status;
}

static __be32
nfsd4_verify(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             struct nfsd4_verify *verify)
{
        __be32 status;

        status = _nfsd4_verify(rqstp, cstate, verify);
        return status == nfserr_same ? nfs_ok : status;
}

/*
 * NULL call.
 */
static __be32
nfsd4_proc_null(struct svc_rqst *rqstp, void *argp, void *resp)
{
        return nfs_ok;
}

static inline void nfsd4_increment_op_stats(u32 opnum)
{
        if (opnum >= FIRST_NFS4_OP && opnum <= LAST_NFS4_OP)
                nfsdstats.nfs4_opcount[opnum]++;
}

static void cstate_free(struct nfsd4_compound_state *cstate)
{
        if (cstate == NULL)
                return;
        fh_put(&cstate->current_fh);
        fh_put(&cstate->save_fh);
        BUG_ON(cstate->replay_owner);
        kfree(cstate);
}

static struct nfsd4_compound_state *cstate_alloc(void)
{
        struct nfsd4_compound_state *cstate;

        cstate = kmalloc(sizeof(struct nfsd4_compound_state), GFP_KERNEL);
        if (cstate == NULL)
                return NULL;
        fh_init(&cstate->current_fh, NFS4_FHSIZE);
        fh_init(&cstate->save_fh, NFS4_FHSIZE);
        cstate->replay_owner = NULL;
        return cstate;
}

typedef __be32(*nfsd4op_func)(struct svc_rqst *, struct nfsd4_compound_state *,
                              void *);

struct nfsd4_operation {
        nfsd4op_func op_func;
        u32 op_flags;
/* Most ops require a valid current filehandle; a few don't: */
#define ALLOWED_WITHOUT_FH 1
/* GETATTR and ops not listed as returning NFS4ERR_MOVED: */
#define ALLOWED_ON_ABSENT_FS 2
        char *op_name;
};

static struct nfsd4_operation nfsd4_ops[];

static inline char *nfsd4_op_name(unsigned opnum);

/*
 * COMPOUND call.
 */
static __be32
nfsd4_proc_compound(struct svc_rqst *rqstp,
                    struct nfsd4_compoundargs *args,
                    struct nfsd4_compoundres *resp)
{
        struct nfsd4_op *op;
        struct nfsd4_operation *opdesc;
        struct nfsd4_compound_state *cstate = NULL;
        int             slack_bytes;
        __be32          status;

        status = nfserr_resource;
        cstate = cstate_alloc();
        if (cstate == NULL)
                goto out;

        resp->xbuf = &rqstp->rq_res;
        resp->p = rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len;
        resp->tagp = resp->p;
        /* reserve space for: taglen, tag, and opcnt */
        resp->p += 2 + XDR_QUADLEN(args->taglen);
        resp->end = rqstp->rq_res.head[0].iov_base + PAGE_SIZE;
        resp->taglen = args->taglen;
        resp->tag = args->tag;
        resp->opcnt = 0;
        resp->rqstp = rqstp;

        /*
         * According to RFC3010, this takes precedence over all other errors.
         */
        status = nfserr_minor_vers_mismatch;
        if (args->minorversion > NFSD_SUPPORTED_MINOR_VERSION)
                goto out;

        status = nfs_ok;
        while (!status && resp->opcnt < args->opcnt) {
                op = &args->ops[resp->opcnt++];

                dprintk("nfsv4 compound op #%d/%d: %d (%s)\n",
                        resp->opcnt, args->opcnt, op->opnum,
                        nfsd4_op_name(op->opnum));

                /*
                 * The XDR decode routines may have pre-set op->status;
                 * for example, if there is a miscellaneous XDR error
                 * it will be set to nfserr_bad_xdr.
                 */
                if (op->status)
                        goto encode_op;

                /* We must be able to encode a successful response to
                 * this operation, with enough room left over to encode a
                 * failed response to the next operation.  If we don't
                 * have enough room, fail with ERR_RESOURCE.
                 */
                slack_bytes = (char *)resp->end - (char *)resp->p;
                if (slack_bytes < COMPOUND_SLACK_SPACE
                                + COMPOUND_ERR_SLACK_SPACE) {
                        BUG_ON(slack_bytes < COMPOUND_ERR_SLACK_SPACE);
                        op->status = nfserr_resource;
                        goto encode_op;
                }

                opdesc = &nfsd4_ops[op->opnum];

                if (!cstate->current_fh.fh_dentry) {
                        if (!(opdesc->op_flags & ALLOWED_WITHOUT_FH)) {
                                op->status = nfserr_nofilehandle;
                                goto encode_op;
                        }
                } else if (cstate->current_fh.fh_export->ex_fslocs.migrated &&
                          !(opdesc->op_flags & ALLOWED_ON_ABSENT_FS)) {
                        op->status = nfserr_moved;
                        goto encode_op;
                }

                if (opdesc->op_func)
                        op->status = opdesc->op_func(rqstp, cstate, &op->u);
                else
                        BUG_ON(op->status == nfs_ok);

encode_op:
                if (op->status == nfserr_replay_me) {
                        op->replay = &cstate->replay_owner->so_replay;
                        nfsd4_encode_replay(resp, op);
                        status = op->status = op->replay->rp_status;
                } else {
                        nfsd4_encode_operation(resp, op);
                        status = op->status;
                }
                if (cstate->replay_owner) {
                        nfs4_put_stateowner(cstate->replay_owner);
                        cstate->replay_owner = NULL;
                }
                /* XXX Ugh, we need to get rid of this kind of special case: */
                if (op->opnum == OP_READ && op->u.read.rd_filp)
                        fput(op->u.read.rd_filp);

                nfsd4_increment_op_stats(op->opnum);
        }

out:
        nfsd4_release_compoundargs(args);
        cstate_free(cstate);
        dprintk("nfsv4 compound returned %d\n", ntohl(status));
        return status;
}

static struct nfsd4_operation nfsd4_ops[OP_RELEASE_LOCKOWNER+1] = {
        [OP_ACCESS] = {
                .op_func = (nfsd4op_func)nfsd4_access,
                .op_name = "OP_ACCESS",
        },
        [OP_CLOSE] = {
                .op_func = (nfsd4op_func)nfsd4_close,
                .op_name = "OP_CLOSE",
        },
        [OP_COMMIT] = {
                .op_func = (nfsd4op_func)nfsd4_commit,
                .op_name = "OP_COMMIT",
        },
        [OP_CREATE] = {
                .op_func = (nfsd4op_func)nfsd4_create,
                .op_name = "OP_CREATE",
        },
        [OP_DELEGRETURN] = {
                .op_func = (nfsd4op_func)nfsd4_delegreturn,
                .op_name = "OP_DELEGRETURN",
        },
        [OP_GETATTR] = {
                .op_func = (nfsd4op_func)nfsd4_getattr,
                .op_flags = ALLOWED_ON_ABSENT_FS,
                .op_name = "OP_GETATTR",
        },
        [OP_GETFH] = {
                .op_func = (nfsd4op_func)nfsd4_getfh,
                .op_name = "OP_GETFH",
        },
        [OP_LINK] = {
                .op_func = (nfsd4op_func)nfsd4_link,
                .op_name = "OP_LINK",
        },
        [OP_LOCK] = {
                .op_func = (nfsd4op_func)nfsd4_lock,
                .op_name = "OP_LOCK",
        },
        [OP_LOCKT] = {
                .op_func = (nfsd4op_func)nfsd4_lockt,
                .op_name = "OP_LOCKT",
        },
        [OP_LOCKU] = {
                .op_func = (nfsd4op_func)nfsd4_locku,
                .op_name = "OP_LOCKU",
        },
        [OP_LOOKUP] = {
                .op_func = (nfsd4op_func)nfsd4_lookup,
                .op_name = "OP_LOOKUP",
        },
        [OP_LOOKUPP] = {
                .op_func = (nfsd4op_func)nfsd4_lookupp,
                .op_name = "OP_LOOKUPP",
        },
        [OP_NVERIFY] = {
                .op_func = (nfsd4op_func)nfsd4_nverify,
                .op_name = "OP_NVERIFY",
        },
        [OP_OPEN] = {
                .op_func = (nfsd4op_func)nfsd4_open,
                .op_name = "OP_OPEN",
        },
        [OP_OPEN_CONFIRM] = {
                .op_func = (nfsd4op_func)nfsd4_open_confirm,
                .op_name = "OP_OPEN_CONFIRM",
        },
        [OP_OPEN_DOWNGRADE] = {
                .op_func = (nfsd4op_func)nfsd4_open_downgrade,
                .op_name = "OP_OPEN_DOWNGRADE",
        },
        [OP_PUTFH] = {
                .op_func = (nfsd4op_func)nfsd4_putfh,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
                .op_name = "OP_PUTFH",
        },
        [OP_PUTPUBFH] = {
                /* unsupported, just for future reference: */
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
                .op_name = "OP_PUTPUBFH",
        },
        [OP_PUTROOTFH] = {
                .op_func = (nfsd4op_func)nfsd4_putrootfh,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
                .op_name = "OP_PUTROOTFH",
        },
        [OP_READ] = {
                .op_func = (nfsd4op_func)nfsd4_read,
                .op_name = "OP_READ",
        },
        [OP_READDIR] = {
                .op_func = (nfsd4op_func)nfsd4_readdir,
                .op_name = "OP_READDIR",
        },
        [OP_READLINK] = {
                .op_func = (nfsd4op_func)nfsd4_readlink,
                .op_name = "OP_READLINK",
        },
        [OP_REMOVE] = {
                .op_func = (nfsd4op_func)nfsd4_remove,
                .op_name = "OP_REMOVE",
        },
        [OP_RENAME] = {
                .op_name = "OP_RENAME",
                .op_func = (nfsd4op_func)nfsd4_rename,
        },
        [OP_RENEW] = {
                .op_func = (nfsd4op_func)nfsd4_renew,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
                .op_name = "OP_RENEW",
        },
        [OP_RESTOREFH] = {
                .op_func = (nfsd4op_func)nfsd4_restorefh,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
                .op_name = "OP_RESTOREFH",
        },
        [OP_SAVEFH] = {
                .op_func = (nfsd4op_func)nfsd4_savefh,
                .op_name = "OP_SAVEFH",
        },
        [OP_SECINFO] = {
                .op_func = (nfsd4op_func)nfsd4_secinfo,
                .op_name = "OP_SECINFO",
        },
        [OP_SETATTR] = {
                .op_func = (nfsd4op_func)nfsd4_setattr,
                .op_name = "OP_SETATTR",
        },
        [OP_SETCLIENTID] = {
                .op_func = (nfsd4op_func)nfsd4_setclientid,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
                .op_name = "OP_SETCLIENTID",
        },
        [OP_SETCLIENTID_CONFIRM] = {
                .op_func = (nfsd4op_func)nfsd4_setclientid_confirm,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
                .op_name = "OP_SETCLIENTID_CONFIRM",
        },
        [OP_VERIFY] = {
                .op_func = (nfsd4op_func)nfsd4_verify,
                .op_name = "OP_VERIFY",
        },
        [OP_WRITE] = {
                .op_func = (nfsd4op_func)nfsd4_write,
                .op_name = "OP_WRITE",
        },
        [OP_RELEASE_LOCKOWNER] = {
                .op_func = (nfsd4op_func)nfsd4_release_lockowner,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
                .op_name = "OP_RELEASE_LOCKOWNER",
        },
};

static inline char *
nfsd4_op_name(unsigned opnum)
{
        if (opnum < ARRAY_SIZE(nfsd4_ops))
                return nfsd4_ops[opnum].op_name;
        return "unknown_operation";
}

#define nfs4svc_decode_voidargs         NULL
#define nfs4svc_release_void            NULL
#define nfsd4_voidres                   nfsd4_voidargs
#define nfs4svc_release_compound        NULL
struct nfsd4_voidargs { int dummy; };

#define PROC(name, argt, rest, relt, cache, respsize)   \
 { (svc_procfunc) nfsd4_proc_##name,            \
   (kxdrproc_t) nfs4svc_decode_##argt##args,    \
   (kxdrproc_t) nfs4svc_encode_##rest##res,     \
   (kxdrproc_t) nfs4svc_release_##relt,         \
   sizeof(struct nfsd4_##argt##args),           \
   sizeof(struct nfsd4_##rest##res),            \
   0,                                           \
   cache,                                       \
   respsize,                                    \
 }

/*
 * TODO: At the present time, the NFSv4 server does not do XID caching
 * of requests.  Implementing XID caching would not be a serious problem,
 * although it would require a mild change in interfaces since one
 * doesn't know whether an NFSv4 request is idempotent until after the
 * XDR decode.  However, XID caching totally confuses pynfs (Peter
 * Astrand's regression testsuite for NFSv4 servers), which reuses
 * XID's liberally, so I've left it unimplemented until pynfs generates
 * better XID's.
 */
static struct svc_procedure             nfsd_procedures4[2] = {
  PROC(null,     void,          void,           void,     RC_NOCACHE, 1),
  PROC(compound, compound,      compound,       compound, RC_NOCACHE, NFSD_BUFSIZE/4)
};

struct svc_version      nfsd_version4 = {
                .vs_vers        = 4,
                .vs_nproc       = 2,
                .vs_proc        = nfsd_procedures4,
                .vs_dispatch    = nfsd_dispatch,
                .vs_xdrsize     = NFS4_SVC_XDRSIZE,
};

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