[PATCH] nfsd4: don't create on open that fails due to ERR_GRACE

[linux-2.6.22.y-op.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.
 *
 * Note: some routines in this file are just trivial wrappers
 * (e.g. nfsd4_lookup()) defined solely for the sake of consistent
 * naming.  Since all such routines have been declared "inline",
 * there shouldn't be any associated overhead.  At some point in
 * the future, I might inline these "by hand" to clean up a
 * little.
 */

#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>

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

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

        accmode = MAY_NOP;
        if (open->op_share_access & NFS4_SHARE_ACCESS_READ)
                accmode = MAY_READ;
        if (open->op_share_deny & NFS4_SHARE_ACCESS_WRITE)
                accmode |= (MAY_WRITE | MAY_TRUNC);
        accmode |= MAY_OWNER_OVERRIDE;

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

        return status;
}

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

        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);
        }
        else {
                status = nfsd_lookup(rqstp, current_fh,
                                     open->op_fname.data, open->op_fname.len, &resfh);
                fh_unlock(current_fh);
        }

        if (!status) {
                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);

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

        fh_put(&resfh);
        return status;
}

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

        return status;
}


static inline int
nfsd4_open(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open, struct nfs4_stateowner **replay_owner)
{
        int 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(current_fh);
                current_fh->fh_handle.fh_size = rp->rp_openfh_len;
                memcpy(&current_fh->fh_handle.fh_base, rp->rp_openfh,
                                rp->rp_openfh_len);
                status = fh_verify(rqstp, current_fh, 0, 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: */
        if (nfs4_in_grace() && open->op_claim_type != NFS4_OPEN_CLAIM_PREVIOUS)
                return nfserr_grace;
        if (!nfs4_in_grace() && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)
                return nfserr_no_grace;

        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, 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, current_fh, open);
                        if (status)
                                goto out;
                        break;
                case NFS4_OPEN_CLAIM_DELEGATE_PREV:
                        open->op_stateowner->so_confirmed = 1;
                        printk("NFSD: unsupported OPEN claim type %d\n",
                                open->op_claim_type);
                        status = nfserr_notsupp;
                        goto out;
                default:
                        printk("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, current_fh, open);
out:
        if (open->op_stateowner) {
                nfs4_get_stateowner(open->op_stateowner);
                *replay_owner = open->op_stateowner;
        }
        nfs4_unlock_state();
        return status;
}

/*
 * filehandle-manipulating ops.
 */
static inline int
nfsd4_getfh(struct svc_fh *current_fh, struct svc_fh **getfh)
{
        if (!current_fh->fh_dentry)
                return nfserr_nofilehandle;

        *getfh = current_fh;
        return nfs_ok;
}

static inline int
nfsd4_putfh(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_putfh *putfh)
{
        fh_put(current_fh);
        current_fh->fh_handle.fh_size = putfh->pf_fhlen;
        memcpy(&current_fh->fh_handle.fh_base, putfh->pf_fhval, putfh->pf_fhlen);
        return fh_verify(rqstp, current_fh, 0, MAY_NOP);
}

static inline int
nfsd4_putrootfh(struct svc_rqst *rqstp, struct svc_fh *current_fh)
{
        int status;

        fh_put(current_fh);
        status = exp_pseudoroot(rqstp->rq_client, current_fh,
                              &rqstp->rq_chandle);
        if (!status)
                status = nfserrno(nfsd_setuser(rqstp, current_fh->fh_export));
        return status;
}

static inline int
nfsd4_restorefh(struct svc_fh *current_fh, struct svc_fh *save_fh)
{
        if (!save_fh->fh_dentry)
                return nfserr_restorefh;

        fh_dup2(current_fh, save_fh);
        return nfs_ok;
}

static inline int
nfsd4_savefh(struct svc_fh *current_fh, struct svc_fh *save_fh)
{
        if (!current_fh->fh_dentry)
                return nfserr_nofilehandle;

        fh_dup2(save_fh, current_fh);
        return nfs_ok;
}

/*
 * misc nfsv4 ops
 */
static inline int
nfsd4_access(struct svc_rqst *rqstp, struct svc_fh *current_fh, 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, current_fh, &access->ac_resp_access, &access->ac_supported);
}

static inline int
nfsd4_commit(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_commit *commit)
{
        int status;

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

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

static int
nfsd4_create(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_create *create)
{
        struct svc_fh resfh;
        int status;
        dev_t rdev;

        fh_init(&resfh, NFS4_FHSIZE);

        status = fh_verify(rqstp, current_fh, S_IFDIR, 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, 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, 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, current_fh, create->cr_name,
                                     create->cr_namelen, &create->cr_iattr,
                                     S_IFCHR, rdev, &resfh);
                break;

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

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

        default:
                status = nfserr_badtype;
        }

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

        fh_put(&resfh);
        return status;
}

static inline int
nfsd4_getattr(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_getattr *getattr)
{
        int status;

        status = fh_verify(rqstp, current_fh, 0, 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 = current_fh;
        return nfs_ok;
}

static inline int
nfsd4_link(struct svc_rqst *rqstp, struct svc_fh *current_fh,
           struct svc_fh *save_fh, struct nfsd4_link *link)
{
        int status = nfserr_nofilehandle;

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

static int
nfsd4_lookupp(struct svc_rqst *rqstp, struct svc_fh *current_fh)
{
        struct svc_fh tmp_fh;
        int ret;

        fh_init(&tmp_fh, NFS4_FHSIZE);
        if((ret = exp_pseudoroot(rqstp->rq_client, &tmp_fh,
                              &rqstp->rq_chandle)) != 0)
                return ret;
        if (tmp_fh.fh_dentry == current_fh->fh_dentry) {
                fh_put(&tmp_fh);
                return nfserr_noent;
        }
        fh_put(&tmp_fh);
        return nfsd_lookup(rqstp, current_fh, "..", 2, current_fh);
}

static inline int
nfsd4_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lookup *lookup)
{
        return nfsd_lookup(rqstp, current_fh, lookup->lo_name, lookup->lo_len, current_fh);
}

static inline int
nfsd4_read(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_read *read)
{
        int 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(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 = current_fh;
        return status;
}

static inline int
nfsd4_readdir(struct svc_rqst *rqstp, struct svc_fh *current_fh, 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 = current_fh;
        return nfs_ok;
}

static inline int
nfsd4_readlink(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_readlink *readlink)
{
        readlink->rl_rqstp = rqstp;
        readlink->rl_fhp = current_fh;
        return nfs_ok;
}

static inline int
nfsd4_remove(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_remove *remove)
{
        int status;

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

static inline int
nfsd4_rename(struct svc_rqst *rqstp, struct svc_fh *current_fh,
             struct svc_fh *save_fh, struct nfsd4_rename *rename)
{
        int status = nfserr_nofilehandle;

        if (!save_fh->fh_dentry)
                return status;
        if (nfs4_in_grace() && !(save_fh->fh_export->ex_flags
                                        & NFSEXP_NOSUBTREECHECK))
                return nfserr_grace;
        status = nfsd_rename(rqstp, save_fh, rename->rn_sname,
                             rename->rn_snamelen, 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(save_fh->fh_dentry->d_inode->i_mode) &&
                   S_ISDIR(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, current_fh);
                set_change_info(&rename->rn_tinfo, save_fh);
        }
        return status;
}

static inline int
nfsd4_setattr(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_setattr *setattr)
{
        int status = nfs_ok;

        if (!current_fh->fh_dentry)
                return nfserr_nofilehandle;

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

static inline int
nfsd4_write(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_write *write)
{
        stateid_t *stateid = &write->wr_stateid;
        struct file *filp = NULL;
        u32 *p;
        int 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(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, current_fh, filp, write->wr_offset,
                        write->wr_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 int
nfsd4_verify(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_verify *verify)
{
        u32 *buf, *p;
        int count;
        int status;

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

        /* 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;
}

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


/*
 * COMPOUND call.
 */
static int
nfsd4_proc_compound(struct svc_rqst *rqstp,
                    struct nfsd4_compoundargs *args,
                    struct nfsd4_compoundres *resp)
{
        struct nfsd4_op *op;
        struct svc_fh   *current_fh = NULL;
        struct svc_fh   *save_fh = NULL;
        struct nfs4_stateowner *replay_owner = NULL;
        int             slack_space;    /* in words, not bytes! */
        int             status;

        status = nfserr_resource;
        current_fh = kmalloc(sizeof(*current_fh), GFP_KERNEL);
        if (current_fh == NULL)
                goto out;
        fh_init(current_fh, NFS4_FHSIZE);
        save_fh = kmalloc(sizeof(*save_fh), GFP_KERNEL);
        if (save_fh == NULL)
                goto out;
        fh_init(save_fh, NFS4_FHSIZE);

        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\n", resp->opcnt, 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.
                 */
/* FIXME - is slack_space *really* words, or bytes??? - neilb */
                slack_space = (char *)resp->end - (char *)resp->p;
                if (slack_space < COMPOUND_SLACK_SPACE + COMPOUND_ERR_SLACK_SPACE) {
                        BUG_ON(slack_space < COMPOUND_ERR_SLACK_SPACE);
                        op->status = nfserr_resource;
                        goto encode_op;
                }

                /* All operations except RENEW, SETCLIENTID, RESTOREFH
                * SETCLIENTID_CONFIRM, PUTFH and PUTROOTFH
                * require a valid current filehandle
                *
                * SETATTR NOFILEHANDLE error handled in nfsd4_setattr
                * due to required returned bitmap argument
                */
                if ((!current_fh->fh_dentry) &&
                   !((op->opnum == OP_PUTFH) || (op->opnum == OP_PUTROOTFH) ||
                   (op->opnum == OP_SETCLIENTID) ||
                   (op->opnum == OP_SETCLIENTID_CONFIRM) ||
                   (op->opnum == OP_RENEW) || (op->opnum == OP_RESTOREFH) ||
                   (op->opnum == OP_RELEASE_LOCKOWNER) ||
                   (op->opnum == OP_SETATTR))) {
                        op->status = nfserr_nofilehandle;
                        goto encode_op;
                }
                switch (op->opnum) {
                case OP_ACCESS:
                        op->status = nfsd4_access(rqstp, current_fh, &op->u.access);
                        break;
                case OP_CLOSE:
                        op->status = nfsd4_close(rqstp, current_fh, &op->u.close, &replay_owner);
                        break;
                case OP_COMMIT:
                        op->status = nfsd4_commit(rqstp, current_fh, &op->u.commit);
                        break;
                case OP_CREATE:
                        op->status = nfsd4_create(rqstp, current_fh, &op->u.create);
                        break;
                case OP_DELEGRETURN:
                        op->status = nfsd4_delegreturn(rqstp, current_fh, &op->u.delegreturn);
                        break;
                case OP_GETATTR:
                        op->status = nfsd4_getattr(rqstp, current_fh, &op->u.getattr);
                        break;
                case OP_GETFH:
                        op->status = nfsd4_getfh(current_fh, &op->u.getfh);
                        break;
                case OP_LINK:
                        op->status = nfsd4_link(rqstp, current_fh, save_fh, &op->u.link);
                        break;
                case OP_LOCK:
                        op->status = nfsd4_lock(rqstp, current_fh, &op->u.lock, &replay_owner);
                        break;
                case OP_LOCKT:
                        op->status = nfsd4_lockt(rqstp, current_fh, &op->u.lockt);
                        break;
                case OP_LOCKU:
                        op->status = nfsd4_locku(rqstp, current_fh, &op->u.locku, &replay_owner);
                        break;
                case OP_LOOKUP:
                        op->status = nfsd4_lookup(rqstp, current_fh, &op->u.lookup);
                        break;
                case OP_LOOKUPP:
                        op->status = nfsd4_lookupp(rqstp, current_fh);
                        break;
                case OP_NVERIFY:
                        op->status = nfsd4_verify(rqstp, current_fh, &op->u.nverify);
                        if (op->status == nfserr_not_same)
                                op->status = nfs_ok;
                        break;
                case OP_OPEN:
                        op->status = nfsd4_open(rqstp, current_fh, &op->u.open, &replay_owner);
                        break;
                case OP_OPEN_CONFIRM:
                        op->status = nfsd4_open_confirm(rqstp, current_fh, &op->u.open_confirm, &replay_owner);
                        break;
                case OP_OPEN_DOWNGRADE:
                        op->status = nfsd4_open_downgrade(rqstp, current_fh, &op->u.open_downgrade, &replay_owner);
                        break;
                case OP_PUTFH:
                        op->status = nfsd4_putfh(rqstp, current_fh, &op->u.putfh);
                        break;
                case OP_PUTROOTFH:
                        op->status = nfsd4_putrootfh(rqstp, current_fh);
                        break;
                case OP_READ:
                        op->status = nfsd4_read(rqstp, current_fh, &op->u.read);
                        break;
                case OP_READDIR:
                        op->status = nfsd4_readdir(rqstp, current_fh, &op->u.readdir);
                        break;
                case OP_READLINK:
                        op->status = nfsd4_readlink(rqstp, current_fh, &op->u.readlink);
                        break;
                case OP_REMOVE:
                        op->status = nfsd4_remove(rqstp, current_fh, &op->u.remove);
                        break;
                case OP_RENAME:
                        op->status = nfsd4_rename(rqstp, current_fh, save_fh, &op->u.rename);
                        break;
                case OP_RENEW:
                        op->status = nfsd4_renew(&op->u.renew);
                        break;
                case OP_RESTOREFH:
                        op->status = nfsd4_restorefh(current_fh, save_fh);
                        break;
                case OP_SAVEFH:
                        op->status = nfsd4_savefh(current_fh, save_fh);
                        break;
                case OP_SETATTR:
                        op->status = nfsd4_setattr(rqstp, current_fh, &op->u.setattr);
                        break;
                case OP_SETCLIENTID:
                        op->status = nfsd4_setclientid(rqstp, &op->u.setclientid);
                        break;
                case OP_SETCLIENTID_CONFIRM:
                        op->status = nfsd4_setclientid_confirm(rqstp, &op->u.setclientid_confirm);
                        break;
                case OP_VERIFY:
                        op->status = nfsd4_verify(rqstp, current_fh, &op->u.verify);
                        if (op->status == nfserr_same)
                                op->status = nfs_ok;
                        break;
                case OP_WRITE:
                        op->status = nfsd4_write(rqstp, current_fh, &op->u.write);
                        break;
                case OP_RELEASE_LOCKOWNER:
                        op->status = nfsd4_release_lockowner(rqstp, &op->u.release_lockowner);
                        break;
                default:
                        BUG_ON(op->status == nfs_ok);
                        break;
                }

encode_op:
                if (op->status == NFSERR_REPLAY_ME) {
                        op->replay = &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 (replay_owner && (replay_owner != (void *)(-1))) {
                        nfs4_put_stateowner(replay_owner);
                        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);
        }

out:
        nfsd4_release_compoundargs(args);
        if (current_fh)
                fh_put(current_fh);
        kfree(current_fh);
        if (save_fh)
                fh_put(save_fh);
        kfree(save_fh);
        return status;
}

#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)
};

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:
 */