fuse: Convert fuse_readpages_end() to use folio_end_read()

[linux.git] / fs / nfsd / nfs4proc.c

/*
 *  Server-side procedures for NFSv4.
 *
 *  Copyright (c) 2002 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Kendrick Smith <[email protected]>
 *  Andy Adamson   <[email protected]>
 *
 *  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/fs_struct.h>
#include <linux/file.h>
#include <linux/falloc.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/namei.h>

#include <linux/sunrpc/addr.h>
#include <linux/nfs_ssc.h>

#include "idmap.h"
#include "cache.h"
#include "xdr4.h"
#include "vfs.h"
#include "current_stateid.h"
#include "netns.h"
#include "acl.h"
#include "pnfs.h"
#include "trace.h"

static bool inter_copy_offload_enable;
module_param(inter_copy_offload_enable, bool, 0644);
MODULE_PARM_DESC(inter_copy_offload_enable,
                 "Enable inter server to server copy offload. Default: false");

#ifdef CONFIG_NFSD_V4_2_INTER_SSC
static int nfsd4_ssc_umount_timeout = 900000;           /* default to 15 mins */
module_param(nfsd4_ssc_umount_timeout, int, 0644);
MODULE_PARM_DESC(nfsd4_ssc_umount_timeout,
                "idle msecs before unmount export from source server");
#endif

#define NFSDDBG_FACILITY                NFSDDBG_PROC

static u32 nfsd_attrmask[] = {
        NFSD_WRITEABLE_ATTRS_WORD0,
        NFSD_WRITEABLE_ATTRS_WORD1,
        NFSD_WRITEABLE_ATTRS_WORD2
};

static u32 nfsd41_ex_attrmask[] = {
        NFSD_SUPPATTR_EXCLCREAT_WORD0,
        NFSD_SUPPATTR_EXCLCREAT_WORD1,
        NFSD_SUPPATTR_EXCLCREAT_WORD2
};

static __be32
check_attr_support(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                   u32 *bmval, u32 *writable)
{
        struct dentry *dentry = cstate->current_fh.fh_dentry;
        struct svc_export *exp = cstate->current_fh.fh_export;

        if (!nfsd_attrs_supported(cstate->minorversion, bmval))
                return nfserr_attrnotsupp;
        if ((bmval[0] & FATTR4_WORD0_ACL) && !IS_POSIXACL(d_inode(dentry)))
                return nfserr_attrnotsupp;
        if ((bmval[2] & FATTR4_WORD2_SECURITY_LABEL) &&
                        !(exp->ex_flags & NFSEXP_SECURITY_LABEL))
                return nfserr_attrnotsupp;
        if (writable && !bmval_is_subset(bmval, writable))
                return nfserr_inval;
        if (writable && (bmval[2] & FATTR4_WORD2_MODE_UMASK) &&
                        (bmval[1] & FATTR4_WORD1_MODE))
                return nfserr_inval;
        return nfs_ok;
}

static __be32
nfsd4_check_open_attributes(struct svc_rqst *rqstp,
        struct nfsd4_compound_state *cstate, struct nfsd4_open *open)
{
        __be32 status = nfs_ok;

        if (open->op_create == NFS4_OPEN_CREATE) {
                if (open->op_createmode == NFS4_CREATE_UNCHECKED
                    || open->op_createmode == NFS4_CREATE_GUARDED)
                        status = check_attr_support(rqstp, cstate,
                                        open->op_bmval, nfsd_attrmask);
                else if (open->op_createmode == NFS4_CREATE_EXCLUSIVE4_1)
                        status = check_attr_support(rqstp, cstate,
                                        open->op_bmval, nfsd41_ex_attrmask);
        }

        return status;
}

static int
is_create_with_attrs(struct nfsd4_open *open)
{
        return open->op_create == NFS4_OPEN_CREATE
                && (open->op_createmode == NFS4_CREATE_UNCHECKED
                    || open->op_createmode == NFS4_CREATE_GUARDED
                    || open->op_createmode == NFS4_CREATE_EXCLUSIVE4_1);
}

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

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

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

        accmode |= NFSD_MAY_READ_IF_EXEC;

        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_READ)
                accmode |= NFSD_MAY_WRITE;

        return fh_verify(rqstp, current_fh, S_IFREG, accmode);
}

static __be32 nfsd_check_obj_isreg(struct svc_fh *fh)
{
        umode_t mode = d_inode(fh->fh_dentry)->i_mode;

        if (S_ISREG(mode))
                return nfs_ok;
        if (S_ISDIR(mode))
                return nfserr_isdir;
        /*
         * Using err_symlink as our catch-all case may look odd; but
         * there's no other obvious error for this case in 4.0, and we
         * happen to know that it will cause the linux v4 client to do
         * the right thing on attempts to open something other than a
         * regular file.
         */
        return nfserr_symlink;
}

static void nfsd4_set_open_owner_reply_cache(struct nfsd4_compound_state *cstate, struct nfsd4_open *open, struct svc_fh *resfh)
{
        if (nfsd4_has_session(cstate))
                return;
        fh_copy_shallow(&open->op_openowner->oo_owner.so_replay.rp_openfh,
                        &resfh->fh_handle);
}

static inline bool nfsd4_create_is_exclusive(int createmode)
{
        return createmode == NFS4_CREATE_EXCLUSIVE ||
                createmode == NFS4_CREATE_EXCLUSIVE4_1;
}

static __be32
nfsd4_vfs_create(struct svc_fh *fhp, struct dentry *child,
                 struct nfsd4_open *open)
{
        struct file *filp;
        struct path path;
        int oflags;

        oflags = O_CREAT | O_LARGEFILE;
        switch (open->op_share_access & NFS4_SHARE_ACCESS_BOTH) {
        case NFS4_SHARE_ACCESS_WRITE:
                oflags |= O_WRONLY;
                break;
        case NFS4_SHARE_ACCESS_BOTH:
                oflags |= O_RDWR;
                break;
        default:
                oflags |= O_RDONLY;
        }

        path.mnt = fhp->fh_export->ex_path.mnt;
        path.dentry = child;
        filp = dentry_create(&path, oflags, open->op_iattr.ia_mode,
                             current_cred());
        if (IS_ERR(filp))
                return nfserrno(PTR_ERR(filp));

        open->op_filp = filp;
        return nfs_ok;
}

/*
 * Implement NFSv4's unchecked, guarded, and exclusive create
 * semantics for regular files. Open state for this new file is
 * subsequently fabricated in nfsd4_process_open2().
 *
 * Upon return, caller must release @fhp and @resfhp.
 */
static __be32
nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
                  struct svc_fh *resfhp, struct nfsd4_open *open)
{
        struct iattr *iap = &open->op_iattr;
        struct nfsd_attrs attrs = {
                .na_iattr       = iap,
                .na_seclabel    = &open->op_label,
        };
        struct dentry *parent, *child;
        __u32 v_mtime, v_atime;
        struct inode *inode;
        __be32 status;
        int host_err;

        if (isdotent(open->op_fname, open->op_fnamelen))
                return nfserr_exist;
        if (!(iap->ia_valid & ATTR_MODE))
                iap->ia_mode = 0;

        status = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
        if (status != nfs_ok)
                return status;
        parent = fhp->fh_dentry;
        inode = d_inode(parent);

        host_err = fh_want_write(fhp);
        if (host_err)
                return nfserrno(host_err);

        if (is_create_with_attrs(open))
                nfsd4_acl_to_attr(NF4REG, open->op_acl, &attrs);

        inode_lock_nested(inode, I_MUTEX_PARENT);

        child = lookup_one_len(open->op_fname, parent, open->op_fnamelen);
        if (IS_ERR(child)) {
                status = nfserrno(PTR_ERR(child));
                goto out;
        }

        if (d_really_is_negative(child)) {
                status = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
                if (status != nfs_ok)
                        goto out;
        }

        status = fh_compose(resfhp, fhp->fh_export, child, fhp);
        if (status != nfs_ok)
                goto out;

        v_mtime = 0;
        v_atime = 0;
        if (nfsd4_create_is_exclusive(open->op_createmode)) {
                u32 *verifier = (u32 *)open->op_verf.data;

                /*
                 * Solaris 7 gets confused (bugid 4218508) if these have
                 * the high bit set, as do xfs filesystems without the
                 * "bigtime" feature. So just clear the high bits. If this
                 * is ever changed to use different attrs for storing the
                 * verifier, then do_open_lookup() will also need to be
                 * fixed accordingly.
                 */
                v_mtime = verifier[0] & 0x7fffffff;
                v_atime = verifier[1] & 0x7fffffff;
        }

        if (d_really_is_positive(child)) {
                /* NFSv4 protocol requires change attributes even though
                 * no change happened.
                 */
                status = fh_fill_both_attrs(fhp);
                if (status != nfs_ok)
                        goto out;

                switch (open->op_createmode) {
                case NFS4_CREATE_UNCHECKED:
                        if (!d_is_reg(child))
                                break;

                        /*
                         * In NFSv4, we don't want to truncate the file
                         * now. This would be wrong if the OPEN fails for
                         * some other reason. Furthermore, if the size is
                         * nonzero, we should ignore it according to spec!
                         */
                        open->op_truncate = (iap->ia_valid & ATTR_SIZE) &&
                                                !iap->ia_size;
                        break;
                case NFS4_CREATE_GUARDED:
                        status = nfserr_exist;
                        break;
                case NFS4_CREATE_EXCLUSIVE:
                        if (inode_get_mtime_sec(d_inode(child)) == v_mtime &&
                            inode_get_atime_sec(d_inode(child)) == v_atime &&
                            d_inode(child)->i_size == 0) {
                                open->op_created = true;
                                break;          /* subtle */
                        }
                        status = nfserr_exist;
                        break;
                case NFS4_CREATE_EXCLUSIVE4_1:
                        if (inode_get_mtime_sec(d_inode(child)) == v_mtime &&
                            inode_get_atime_sec(d_inode(child)) == v_atime &&
                            d_inode(child)->i_size == 0) {
                                open->op_created = true;
                                goto set_attr;  /* subtle */
                        }
                        status = nfserr_exist;
                }
                goto out;
        }

        if (!IS_POSIXACL(inode))
                iap->ia_mode &= ~current_umask();

        status = fh_fill_pre_attrs(fhp);
        if (status != nfs_ok)
                goto out;
        status = nfsd4_vfs_create(fhp, child, open);
        if (status != nfs_ok)
                goto out;
        open->op_created = true;
        fh_fill_post_attrs(fhp);

        /* A newly created file already has a file size of zero. */
        if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
                iap->ia_valid &= ~ATTR_SIZE;
        if (nfsd4_create_is_exclusive(open->op_createmode)) {
                iap->ia_valid = ATTR_MTIME | ATTR_ATIME |
                                ATTR_MTIME_SET|ATTR_ATIME_SET;
                iap->ia_mtime.tv_sec = v_mtime;
                iap->ia_atime.tv_sec = v_atime;
                iap->ia_mtime.tv_nsec = 0;
                iap->ia_atime.tv_nsec = 0;
        }

set_attr:
        status = nfsd_create_setattr(rqstp, fhp, resfhp, &attrs);

        if (attrs.na_labelerr)
                open->op_bmval[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
        if (attrs.na_aclerr)
                open->op_bmval[0] &= ~FATTR4_WORD0_ACL;
out:
        inode_unlock(inode);
        nfsd_attrs_free(&attrs);
        if (child && !IS_ERR(child))
                dput(child);
        fh_drop_write(fhp);
        return status;
}

/**
 * set_change_info - set up the change_info4 for a reply
 * @cinfo: pointer to nfsd4_change_info to be populated
 * @fhp: pointer to svc_fh to use as source
 *
 * Many operations in NFSv4 require change_info4 in the reply. This function
 * populates that from the info that we (should!) have already collected. In
 * the event that we didn't get any pre-attrs, just zero out both.
 */
static void
set_change_info(struct nfsd4_change_info *cinfo, struct svc_fh *fhp)
{
        cinfo->atomic = (u32)(fhp->fh_pre_saved && fhp->fh_post_saved && !fhp->fh_no_atomic_attr);
        cinfo->before_change = fhp->fh_pre_change;
        cinfo->after_change = fhp->fh_post_change;

        /*
         * If fetching the pre-change attributes failed, then we should
         * have already failed the whole operation. We could have still
         * failed to fetch post-change attributes however.
         *
         * If we didn't get post-op attrs, just zero-out the after
         * field since we don't know what it should be. If the pre_saved
         * field isn't set for some reason, throw warning and just copy
         * whatever is in the after field.
         */
        if (WARN_ON_ONCE(!fhp->fh_pre_saved))
                cinfo->before_change = 0;
        if (!fhp->fh_post_saved)
                cinfo->after_change = cinfo->before_change + 1;
}

static __be32
do_open_lookup(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, struct nfsd4_open *open, struct svc_fh **resfh)
{
        struct svc_fh *current_fh = &cstate->current_fh;
        int accmode;
        __be32 status;

        *resfh = kmalloc(sizeof(struct svc_fh), GFP_KERNEL);
        if (!*resfh)
                return nfserr_jukebox;
        fh_init(*resfh, NFS4_FHSIZE);
        open->op_truncate = false;

        if (open->op_create) {
                /* FIXME: check session persistence and pnfs flags.
                 * The nfsv4.1 spec requires the following semantics:
                 *
                 * Persistent   | pNFS   | Server REQUIRED | Client Allowed
                 * Reply Cache  | server |                 |
                 * -------------+--------+-----------------+--------------------
                 * no           | no     | EXCLUSIVE4_1    | EXCLUSIVE4_1
                 *              |        |                 | (SHOULD)
                 *              |        | and EXCLUSIVE4  | or EXCLUSIVE4
                 *              |        |                 | (SHOULD NOT)
                 * no           | yes    | EXCLUSIVE4_1    | EXCLUSIVE4_1
                 * yes          | no     | GUARDED4        | GUARDED4
                 * yes          | yes    | GUARDED4        | GUARDED4
                 */

                current->fs->umask = open->op_umask;
                status = nfsd4_create_file(rqstp, current_fh, *resfh, open);
                current->fs->umask = 0;

                /*
                 * Following rfc 3530 14.2.16, and rfc 5661 18.16.4
                 * use the returned bitmask to indicate which attributes
                 * we used to store the verifier:
                 */
                if (nfsd4_create_is_exclusive(open->op_createmode) && status == 0)
                        open->op_bmval[1] |= (FATTR4_WORD1_TIME_ACCESS |
                                                FATTR4_WORD1_TIME_MODIFY);
        } else {
                status = nfsd_lookup(rqstp, current_fh,
                                     open->op_fname, open->op_fnamelen, *resfh);
                if (status == nfs_ok)
                        /* NFSv4 protocol requires change attributes even though
                         * no change happened.
                         */
                        status = fh_fill_both_attrs(current_fh);
        }
        if (status)
                goto out;
        status = nfsd_check_obj_isreg(*resfh);
        if (status)
                goto out;

        nfsd4_set_open_owner_reply_cache(cstate, open, *resfh);
        accmode = NFSD_MAY_NOP;
        if (open->op_created ||
                        open->op_claim_type == NFS4_OPEN_CLAIM_DELEGATE_CUR)
                accmode |= NFSD_MAY_OWNER_OVERRIDE;
        status = do_open_permission(rqstp, *resfh, open, accmode);
        set_change_info(&open->op_cinfo, current_fh);
out:
        return status;
}

static __be32
do_open_fhandle(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, struct nfsd4_open *open)
{
        struct svc_fh *current_fh = &cstate->current_fh;
        int accmode = 0;

        /* 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));

        nfsd4_set_open_owner_reply_cache(cstate, open, current_fh);

        open->op_truncate = (open->op_iattr.ia_valid & ATTR_SIZE) &&
                (open->op_iattr.ia_size == 0);
        /*
         * In the delegation case, the client is telling us about an
         * open that it *already* performed locally, some time ago.  We
         * should let it succeed now if possible.
         *
         * In the case of a CLAIM_FH open, on the other hand, the client
         * may be counting on us to enforce permissions (the Linux 4.1
         * client uses this for normal opens, for example).
         */
        if (open->op_claim_type == NFS4_OPEN_CLAIM_DELEG_CUR_FH)
                accmode = NFSD_MAY_OWNER_OVERRIDE;

        return do_open_permission(rqstp, current_fh, open, accmode);
}

static void
copy_clientid(clientid_t *clid, struct nfsd4_session *session)
{
        struct nfsd4_sessionid *sid =
                        (struct nfsd4_sessionid *)session->se_sessionid.data;

        clid->cl_boot = sid->clientid.cl_boot;
        clid->cl_id = sid->clientid.cl_id;
}

static __be32
nfsd4_open(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           union nfsd4_op_u *u)
{
        struct nfsd4_open *open = &u->open;
        __be32 status;
        struct svc_fh *resfh = NULL;
        struct net *net = SVC_NET(rqstp);
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
        bool reclaim = false;

        dprintk("NFSD: nfsd4_open filename %.*s op_openowner %p\n",
                (int)open->op_fnamelen, open->op_fname,
                open->op_openowner);

        open->op_filp = NULL;
        open->op_rqstp = rqstp;

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

        open->op_created = false;
        /*
         * RFC5661 18.51.3
         * Before RECLAIM_COMPLETE done, server should deny new lock
         */
        if (nfsd4_has_session(cstate) &&
            !test_bit(NFSD4_CLIENT_RECLAIM_COMPLETE, &cstate->clp->cl_flags) &&
            open->op_claim_type != NFS4_OPEN_CLAIM_PREVIOUS)
                return nfserr_grace;

        if (nfsd4_has_session(cstate))
                copy_clientid(&open->op_clientid, cstate->session);

        /* check seqid for replay. set nfs4_owner */
        status = nfsd4_process_open1(cstate, open, nn);
        if (status == nfserr_replay_me) {
                struct nfs4_replay *rp = &open->op_openowner->oo_owner.so_replay;
                fh_put(&cstate->current_fh);
                fh_copy_shallow(&cstate->current_fh.fh_handle,
                                &rp->rp_openfh);
                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;
        if (open->op_xdr_error) {
                status = open->op_xdr_error;
                goto out;
        }

        status = nfsd4_check_open_attributes(rqstp, cstate, open);
        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 (opens_in_grace(net) && open->op_claim_type != NFS4_OPEN_CLAIM_PREVIOUS)
                goto out;
        status = nfserr_no_grace;
        if (!opens_in_grace(net) && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)
                goto out;

        switch (open->op_claim_type) {
        case NFS4_OPEN_CLAIM_DELEGATE_CUR:
        case NFS4_OPEN_CLAIM_NULL:
                status = do_open_lookup(rqstp, cstate, open, &resfh);
                if (status)
                        goto out;
                break;
        case NFS4_OPEN_CLAIM_PREVIOUS:
                status = nfs4_check_open_reclaim(cstate->clp);
                if (status)
                        goto out;
                open->op_openowner->oo_flags |= NFS4_OO_CONFIRMED;
                reclaim = true;
                fallthrough;
        case NFS4_OPEN_CLAIM_FH:
        case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
                status = do_open_fhandle(rqstp, cstate, open);
                if (status)
                        goto out;
                resfh = &cstate->current_fh;
                break;
        case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
        case NFS4_OPEN_CLAIM_DELEGATE_PREV:
                status = nfserr_notsupp;
                goto out;
        default:
                status = nfserr_inval;
                goto out;
        }

        status = nfsd4_process_open2(rqstp, resfh, open);
        if (status && open->op_created)
                pr_warn("nfsd4_process_open2 failed to open newly-created file: status=%u\n",
                        be32_to_cpu(status));
        if (reclaim && !status)
                nn->somebody_reclaimed = true;
out:
        if (open->op_filp) {
                fput(open->op_filp);
                open->op_filp = NULL;
        }
        if (resfh && resfh != &cstate->current_fh) {
                fh_dup2(&cstate->current_fh, resfh);
                fh_put(resfh);
                kfree(resfh);
        }
        nfsd4_cleanup_open_state(cstate, open);
        nfsd4_bump_seqid(cstate, status);
        return status;
}

/*
 * OPEN is the only seqid-mutating operation whose decoding can fail
 * with a seqid-mutating error (specifically, decoding of user names in
 * the attributes).  Therefore we have to do some processing to look up
 * the stateowner so that we can bump the seqid.
 */
static __be32 nfsd4_open_omfg(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, struct nfsd4_op *op)
{
        struct nfsd4_open *open = &op->u.open;

        if (!seqid_mutating_err(ntohl(op->status)))
                return op->status;
        if (nfsd4_has_session(cstate))
                return op->status;
        open->op_xdr_error = op->status;
        return nfsd4_open(rqstp, cstate, &op->u);
}

/*
 * filehandle-manipulating ops.
 */
static __be32
nfsd4_getfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
            union nfsd4_op_u *u)
{
        u->getfh = &cstate->current_fh;
        return nfs_ok;
}

static __be32
nfsd4_putfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
            union nfsd4_op_u *u)
{
        struct nfsd4_putfh *putfh = &u->putfh;
        __be32 ret;

        fh_put(&cstate->current_fh);
        cstate->current_fh.fh_handle.fh_size = putfh->pf_fhlen;
        memcpy(&cstate->current_fh.fh_handle.fh_raw, putfh->pf_fhval,
               putfh->pf_fhlen);
        ret = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_BYPASS_GSS);
#ifdef CONFIG_NFSD_V4_2_INTER_SSC
        if (ret == nfserr_stale && putfh->no_verify) {
                SET_FH_FLAG(&cstate->current_fh, NFSD4_FH_FOREIGN);
                ret = 0;
        }
#endif
        return ret;
}

static __be32
nfsd4_putrootfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                union nfsd4_op_u *u)
{
        fh_put(&cstate->current_fh);

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

static __be32
nfsd4_restorefh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                union nfsd4_op_u *u)
{
        if (!cstate->save_fh.fh_dentry)
                return nfserr_restorefh;

        fh_dup2(&cstate->current_fh, &cstate->save_fh);
        if (HAS_CSTATE_FLAG(cstate, SAVED_STATE_ID_FLAG)) {
                memcpy(&cstate->current_stateid, &cstate->save_stateid, sizeof(stateid_t));
                SET_CSTATE_FLAG(cstate, CURRENT_STATE_ID_FLAG);
        }
        return nfs_ok;
}

static __be32
nfsd4_savefh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             union nfsd4_op_u *u)
{
        fh_dup2(&cstate->save_fh, &cstate->current_fh);
        if (HAS_CSTATE_FLAG(cstate, CURRENT_STATE_ID_FLAG)) {
                memcpy(&cstate->save_stateid, &cstate->current_stateid, sizeof(stateid_t));
                SET_CSTATE_FLAG(cstate, SAVED_STATE_ID_FLAG);
        }
        return nfs_ok;
}

/*
 * misc nfsv4 ops
 */
static __be32
nfsd4_access(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             union nfsd4_op_u *u)
{
        struct nfsd4_access *access = &u->access;
        u32 access_full;

        access_full = NFS3_ACCESS_FULL;
        if (cstate->minorversion >= 2)
                access_full |= NFS4_ACCESS_XALIST | NFS4_ACCESS_XAREAD |
                               NFS4_ACCESS_XAWRITE;

        if (access->ac_req_access & ~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 void gen_boot_verifier(nfs4_verifier *verifier, struct net *net)
{
        __be32 *verf = (__be32 *)verifier->data;

        BUILD_BUG_ON(2*sizeof(*verf) != sizeof(verifier->data));

        nfsd_copy_write_verifier(verf, net_generic(net, nfsd_net_id));
}

static __be32
nfsd4_commit(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             union nfsd4_op_u *u)
{
        struct nfsd4_commit *commit = &u->commit;
        struct nfsd_file *nf;
        __be32 status;

        status = nfsd_file_acquire(rqstp, &cstate->current_fh, NFSD_MAY_WRITE |
                                   NFSD_MAY_NOT_BREAK_LEASE, &nf);
        if (status != nfs_ok)
                return status;

        status = nfsd_commit(rqstp, &cstate->current_fh, nf, commit->co_offset,
                             commit->co_count,
                             (__be32 *)commit->co_verf.data);
        nfsd_file_put(nf);
        return status;
}

static __be32
nfsd4_create(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             union nfsd4_op_u *u)
{
        struct nfsd4_create *create = &u->create;
        struct nfsd_attrs attrs = {
                .na_iattr       = &create->cr_iattr,
                .na_seclabel    = &create->cr_label,
        };
        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_NOP);
        if (status)
                return status;

        status = check_attr_support(rqstp, cstate, create->cr_bmval,
                                    nfsd_attrmask);
        if (status)
                return status;

        status = nfsd4_acl_to_attr(create->cr_type, create->cr_acl, &attrs);
        current->fs->umask = create->cr_umask;
        switch (create->cr_type) {
        case NF4LNK:
                status = nfsd_symlink(rqstp, &cstate->current_fh,
                                      create->cr_name, create->cr_namelen,
                                      create->cr_data, &attrs, &resfh);
                break;

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

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

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

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

        default:
                status = nfserr_badtype;
        }

        if (status)
                goto out;

        if (attrs.na_labelerr)
                create->cr_bmval[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
        if (attrs.na_aclerr)
                create->cr_bmval[0] &= ~FATTR4_WORD0_ACL;
        set_change_info(&create->cr_cinfo, &cstate->current_fh);
        fh_dup2(&cstate->current_fh, &resfh);
out:
        fh_put(&resfh);
out_umask:
        current->fs->umask = 0;
        nfsd_attrs_free(&attrs);
        return status;
}

static __be32
nfsd4_getattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              union nfsd4_op_u *u)
{
        struct nfsd4_getattr *getattr = &u->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_suppattrs[cstate->minorversion][0];
        getattr->ga_bmval[1] &= nfsd_suppattrs[cstate->minorversion][1];
        getattr->ga_bmval[2] &= nfsd_suppattrs[cstate->minorversion][2];

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

static __be32
nfsd4_link(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           union nfsd4_op_u *u)
{
        struct nfsd4_link *link = &u->link;
        __be32 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_do_lookupp(struct svc_rqst *rqstp, struct svc_fh *fh)
{
        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 == fh->fh_dentry) {
                fh_put(&tmp_fh);
                return nfserr_noent;
        }
        fh_put(&tmp_fh);
        return nfsd_lookup(rqstp, fh, "..", 2, fh);
}

static __be32
nfsd4_lookupp(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              union nfsd4_op_u *u)
{
        return nfsd4_do_lookupp(rqstp, &cstate->current_fh);
}

static __be32
nfsd4_lookup(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             union nfsd4_op_u *u)
{
        return nfsd_lookup(rqstp, &cstate->current_fh,
                           u->lookup.lo_name, u->lookup.lo_len,
                           &cstate->current_fh);
}

static __be32
nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           union nfsd4_op_u *u)
{
        struct nfsd4_read *read = &u->read;
        __be32 status;

        read->rd_nf = NULL;

        trace_nfsd_read_start(rqstp, &cstate->current_fh,
                              read->rd_offset, read->rd_length);

        read->rd_length = min_t(u32, read->rd_length, svc_max_payload(rqstp));
        if (read->rd_offset > (u64)OFFSET_MAX)
                read->rd_offset = (u64)OFFSET_MAX;
        if (read->rd_offset + read->rd_length > (u64)OFFSET_MAX)
                read->rd_length = (u64)OFFSET_MAX - read->rd_offset;

        /*
         * If we do a zero copy read, then a client will see read data
         * that reflects the state of the file *after* performing the
         * following compound.
         *
         * To ensure proper ordering, we therefore turn off zero copy if
         * the client wants us to do more in this compound:
         */
        if (!nfsd4_last_compound_op(rqstp)) {
                struct nfsd4_compoundargs *argp = rqstp->rq_argp;

                argp->splice_ok = false;
        }

        /* check stateid */
        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
                                        &read->rd_stateid, RD_STATE,
                                        &read->rd_nf, NULL);

        read->rd_rqstp = rqstp;
        read->rd_fhp = &cstate->current_fh;
        return status;
}


static void
nfsd4_read_release(union nfsd4_op_u *u)
{
        if (u->read.rd_nf)
                nfsd_file_put(u->read.rd_nf);
        trace_nfsd_read_done(u->read.rd_rqstp, u->read.rd_fhp,
                             u->read.rd_offset, u->read.rd_length);
}

static __be32
nfsd4_readdir(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              union nfsd4_op_u *u)
{
        struct nfsd4_readdir *readdir = &u->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_suppattrs[cstate->minorversion][0];
        readdir->rd_bmval[1] &= nfsd_suppattrs[cstate->minorversion][1];
        readdir->rd_bmval[2] &= nfsd_suppattrs[cstate->minorversion][2];

        if ((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,
               union nfsd4_op_u *u)
{
        u->readlink.rl_rqstp = rqstp;
        u->readlink.rl_fhp = &cstate->current_fh;
        return nfs_ok;
}

static __be32
nfsd4_remove(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             union nfsd4_op_u *u)
{
        struct nfsd4_remove *remove = &u->remove;
        __be32 status;

        if (opens_in_grace(SVC_NET(rqstp)))
                return nfserr_grace;
        status = nfsd_unlink(rqstp, &cstate->current_fh, 0,
                             remove->rm_name, remove->rm_namelen);
        if (!status)
                set_change_info(&remove->rm_cinfo, &cstate->current_fh);
        return status;
}

static __be32
nfsd4_rename(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             union nfsd4_op_u *u)
{
        struct nfsd4_rename *rename = &u->rename;
        __be32 status;

        if (opens_in_grace(SVC_NET(rqstp)))
                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);
        if (status)
                return status;
        set_change_info(&rename->rn_sinfo, &cstate->save_fh);
        set_change_info(&rename->rn_tinfo, &cstate->current_fh);
        return nfs_ok;
}

static __be32
nfsd4_secinfo(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              union nfsd4_op_u *u)
{
        struct nfsd4_secinfo *secinfo = &u->secinfo;
        struct svc_export *exp;
        struct dentry *dentry;
        __be32 err;

        err = fh_verify(rqstp, &cstate->current_fh, S_IFDIR, NFSD_MAY_EXEC);
        if (err)
                return err;
        err = nfsd_lookup_dentry(rqstp, &cstate->current_fh,
                                    secinfo->si_name, secinfo->si_namelen,
                                    &exp, &dentry);
        if (err)
                return err;
        if (d_really_is_negative(dentry)) {
                exp_put(exp);
                err = nfserr_noent;
        } else
                secinfo->si_exp = exp;
        dput(dentry);
        if (cstate->minorversion)
                /* See rfc 5661 section 2.6.3.1.1.8 */
                fh_put(&cstate->current_fh);
        return err;
}

static __be32
nfsd4_secinfo_no_name(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                union nfsd4_op_u *u)
{
        __be32 err;

        switch (u->secinfo_no_name.sin_style) {
        case NFS4_SECINFO_STYLE4_CURRENT_FH:
                break;
        case NFS4_SECINFO_STYLE4_PARENT:
                err = nfsd4_do_lookupp(rqstp, &cstate->current_fh);
                if (err)
                        return err;
                break;
        default:
                return nfserr_inval;
        }

        u->secinfo_no_name.sin_exp = exp_get(cstate->current_fh.fh_export);
        fh_put(&cstate->current_fh);
        return nfs_ok;
}

static void
nfsd4_secinfo_release(union nfsd4_op_u *u)
{
        if (u->secinfo.si_exp)
                exp_put(u->secinfo.si_exp);
}

static void
nfsd4_secinfo_no_name_release(union nfsd4_op_u *u)
{
        if (u->secinfo_no_name.sin_exp)
                exp_put(u->secinfo_no_name.sin_exp);
}

static __be32
nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              union nfsd4_op_u *u)
{
        struct nfsd4_setattr *setattr = &u->setattr;
        struct nfsd_attrs attrs = {
                .na_iattr       = &setattr->sa_iattr,
                .na_seclabel    = &setattr->sa_label,
        };
        struct inode *inode;
        __be32 status = nfs_ok;
        bool save_no_wcc;
        int err;

        if (setattr->sa_iattr.ia_valid & ATTR_SIZE) {
                status = nfs4_preprocess_stateid_op(rqstp, cstate,
                                &cstate->current_fh, &setattr->sa_stateid,
                                WR_STATE, NULL, NULL);
                if (status)
                        return status;
        }
        err = fh_want_write(&cstate->current_fh);
        if (err)
                return nfserrno(err);
        status = nfs_ok;

        status = check_attr_support(rqstp, cstate, setattr->sa_bmval,
                                    nfsd_attrmask);
        if (status)
                goto out;

        inode = cstate->current_fh.fh_dentry->d_inode;
        status = nfsd4_acl_to_attr(S_ISDIR(inode->i_mode) ? NF4DIR : NF4REG,
                                   setattr->sa_acl, &attrs);

        if (status)
                goto out;
        save_no_wcc = cstate->current_fh.fh_no_wcc;
        cstate->current_fh.fh_no_wcc = true;
        status = nfsd_setattr(rqstp, &cstate->current_fh, &attrs, NULL);
        cstate->current_fh.fh_no_wcc = save_no_wcc;
        if (!status)
                status = nfserrno(attrs.na_labelerr);
        if (!status)
                status = nfserrno(attrs.na_aclerr);
out:
        nfsd_attrs_free(&attrs);
        fh_drop_write(&cstate->current_fh);
        return status;
}

static __be32
nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
            union nfsd4_op_u *u)
{
        struct nfsd4_write *write = &u->write;
        stateid_t *stateid = &write->wr_stateid;
        struct nfsd_file *nf = NULL;
        __be32 status = nfs_ok;
        unsigned long cnt;
        int nvecs;

        if (write->wr_offset > (u64)OFFSET_MAX ||
            write->wr_offset + write->wr_buflen > (u64)OFFSET_MAX)
                return nfserr_fbig;

        cnt = write->wr_buflen;
        trace_nfsd_write_start(rqstp, &cstate->current_fh,
                               write->wr_offset, cnt);
        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
                                                stateid, WR_STATE, &nf, NULL);
        if (status)
                return status;

        write->wr_how_written = write->wr_stable_how;

        nvecs = svc_fill_write_vector(rqstp, &write->wr_payload);
        WARN_ON_ONCE(nvecs > ARRAY_SIZE(rqstp->rq_vec));

        status = nfsd_vfs_write(rqstp, &cstate->current_fh, nf,
                                write->wr_offset, rqstp->rq_vec, nvecs, &cnt,
                                write->wr_how_written,
                                (__be32 *)write->wr_verifier.data);
        nfsd_file_put(nf);

        write->wr_bytes_written = cnt;
        trace_nfsd_write_done(rqstp, &cstate->current_fh,
                              write->wr_offset, cnt);
        return status;
}

static __be32
nfsd4_verify_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                  stateid_t *src_stateid, struct nfsd_file **src,
                  stateid_t *dst_stateid, struct nfsd_file **dst)
{
        __be32 status;

        if (!cstate->save_fh.fh_dentry)
                return nfserr_nofilehandle;

        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->save_fh,
                                            src_stateid, RD_STATE, src, NULL);
        if (status)
                goto out;

        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
                                            dst_stateid, WR_STATE, dst, NULL);
        if (status)
                goto out_put_src;

        /* fix up for NFS-specific error code */
        if (!S_ISREG(file_inode((*src)->nf_file)->i_mode) ||
            !S_ISREG(file_inode((*dst)->nf_file)->i_mode)) {
                status = nfserr_wrong_type;
                goto out_put_dst;
        }

out:
        return status;
out_put_dst:
        nfsd_file_put(*dst);
        *dst = NULL;
out_put_src:
        nfsd_file_put(*src);
        *src = NULL;
        goto out;
}

static __be32
nfsd4_clone(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                union nfsd4_op_u *u)
{
        struct nfsd4_clone *clone = &u->clone;
        struct nfsd_file *src, *dst;
        __be32 status;

        status = nfsd4_verify_copy(rqstp, cstate, &clone->cl_src_stateid, &src,
                                   &clone->cl_dst_stateid, &dst);
        if (status)
                goto out;

        status = nfsd4_clone_file_range(rqstp, src, clone->cl_src_pos,
                        dst, clone->cl_dst_pos, clone->cl_count,
                        EX_ISSYNC(cstate->current_fh.fh_export));

        nfsd_file_put(dst);
        nfsd_file_put(src);
out:
        return status;
}

static void nfs4_put_copy(struct nfsd4_copy *copy)
{
        if (!refcount_dec_and_test(&copy->refcount))
                return;
        kfree(copy->cp_src);
        kfree(copy);
}

static void nfsd4_stop_copy(struct nfsd4_copy *copy)
{
        if (!test_and_set_bit(NFSD4_COPY_F_STOPPED, &copy->cp_flags))
                kthread_stop(copy->copy_task);
        nfs4_put_copy(copy);
}

static struct nfsd4_copy *nfsd4_get_copy(struct nfs4_client *clp)
{
        struct nfsd4_copy *copy = NULL;

        spin_lock(&clp->async_lock);
        if (!list_empty(&clp->async_copies)) {
                copy = list_first_entry(&clp->async_copies, struct nfsd4_copy,
                                        copies);
                refcount_inc(&copy->refcount);
        }
        spin_unlock(&clp->async_lock);
        return copy;
}

void nfsd4_shutdown_copy(struct nfs4_client *clp)
{
        struct nfsd4_copy *copy;

        while ((copy = nfsd4_get_copy(clp)) != NULL)
                nfsd4_stop_copy(copy);
}
#ifdef CONFIG_NFSD_V4_2_INTER_SSC

extern struct file *nfs42_ssc_open(struct vfsmount *ss_mnt,
                                   struct nfs_fh *src_fh,
                                   nfs4_stateid *stateid);
extern void nfs42_ssc_close(struct file *filep);

extern void nfs_sb_deactive(struct super_block *sb);

#define NFSD42_INTERSSC_MOUNTOPS "vers=4.2,addr=%s,sec=sys"

/*
 * setup a work entry in the ssc delayed unmount list.
 */
static __be32 nfsd4_ssc_setup_dul(struct nfsd_net *nn, char *ipaddr,
                                  struct nfsd4_ssc_umount_item **nsui,
                                  struct svc_rqst *rqstp)
{
        struct nfsd4_ssc_umount_item *ni = NULL;
        struct nfsd4_ssc_umount_item *work = NULL;
        struct nfsd4_ssc_umount_item *tmp;
        DEFINE_WAIT(wait);
        __be32 status = 0;

        *nsui = NULL;
        work = kzalloc(sizeof(*work), GFP_KERNEL);
try_again:
        spin_lock(&nn->nfsd_ssc_lock);
        list_for_each_entry_safe(ni, tmp, &nn->nfsd_ssc_mount_list, nsui_list) {
                if (strncmp(ni->nsui_ipaddr, ipaddr, sizeof(ni->nsui_ipaddr)))
                        continue;
                /* found a match */
                if (ni->nsui_busy) {
                        /*  wait - and try again */
                        prepare_to_wait(&nn->nfsd_ssc_waitq, &wait, TASK_IDLE);
                        spin_unlock(&nn->nfsd_ssc_lock);

                        /* allow 20secs for mount/unmount for now - revisit */
                        if (svc_thread_should_stop(rqstp) ||
                                        (schedule_timeout(20*HZ) == 0)) {
                                finish_wait(&nn->nfsd_ssc_waitq, &wait);
                                kfree(work);
                                return nfserr_eagain;
                        }
                        finish_wait(&nn->nfsd_ssc_waitq, &wait);
                        goto try_again;
                }
                *nsui = ni;
                refcount_inc(&ni->nsui_refcnt);
                spin_unlock(&nn->nfsd_ssc_lock);
                kfree(work);

                /* return vfsmount in (*nsui)->nsui_vfsmount */
                return 0;
        }
        if (work) {
                strscpy(work->nsui_ipaddr, ipaddr, sizeof(work->nsui_ipaddr) - 1);
                refcount_set(&work->nsui_refcnt, 2);
                work->nsui_busy = true;
                list_add_tail(&work->nsui_list, &nn->nfsd_ssc_mount_list);
                *nsui = work;
        } else
                status = nfserr_resource;
        spin_unlock(&nn->nfsd_ssc_lock);
        return status;
}

static void nfsd4_ssc_update_dul(struct nfsd_net *nn,
                                 struct nfsd4_ssc_umount_item *nsui,
                                 struct vfsmount *ss_mnt)
{
        spin_lock(&nn->nfsd_ssc_lock);
        nsui->nsui_vfsmount = ss_mnt;
        nsui->nsui_busy = false;
        wake_up_all(&nn->nfsd_ssc_waitq);
        spin_unlock(&nn->nfsd_ssc_lock);
}

static void nfsd4_ssc_cancel_dul(struct nfsd_net *nn,
                                 struct nfsd4_ssc_umount_item *nsui)
{
        spin_lock(&nn->nfsd_ssc_lock);
        list_del(&nsui->nsui_list);
        wake_up_all(&nn->nfsd_ssc_waitq);
        spin_unlock(&nn->nfsd_ssc_lock);
        kfree(nsui);
}

/*
 * Support one copy source server for now.
 */
static __be32
nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
                       struct nfsd4_ssc_umount_item **nsui)
{
        struct file_system_type *type;
        struct vfsmount *ss_mnt;
        struct nfs42_netaddr *naddr;
        struct sockaddr_storage tmp_addr;
        size_t tmp_addrlen, match_netid_len = 3;
        char *startsep = "", *endsep = "", *match_netid = "tcp";
        char *ipaddr, *dev_name, *raw_data;
        int len, raw_len;
        __be32 status = nfserr_inval;
        struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

        naddr = &nss->u.nl4_addr;
        tmp_addrlen = rpc_uaddr2sockaddr(SVC_NET(rqstp), naddr->addr,
                                         naddr->addr_len,
                                         (struct sockaddr *)&tmp_addr,
                                         sizeof(tmp_addr));
        *nsui = NULL;
        if (tmp_addrlen == 0)
                goto out_err;

        if (tmp_addr.ss_family == AF_INET6) {
                startsep = "[";
                endsep = "]";
                match_netid = "tcp6";
                match_netid_len = 4;
        }

        if (naddr->netid_len != match_netid_len ||
                strncmp(naddr->netid, match_netid, naddr->netid_len))
                goto out_err;

        /* Construct the raw data for the vfs_kern_mount call */
        len = RPC_MAX_ADDRBUFLEN + 1;
        ipaddr = kzalloc(len, GFP_KERNEL);
        if (!ipaddr)
                goto out_err;

        rpc_ntop((struct sockaddr *)&tmp_addr, ipaddr, len);

        /* 2 for ipv6 endsep and startsep. 3 for ":/" and trailing '/0'*/

        raw_len = strlen(NFSD42_INTERSSC_MOUNTOPS) + strlen(ipaddr);
        raw_data = kzalloc(raw_len, GFP_KERNEL);
        if (!raw_data)
                goto out_free_ipaddr;

        snprintf(raw_data, raw_len, NFSD42_INTERSSC_MOUNTOPS, ipaddr);

        status = nfserr_nodev;
        type = get_fs_type("nfs");
        if (!type)
                goto out_free_rawdata;

        /* Set the server:<export> for the vfs_kern_mount call */
        dev_name = kzalloc(len + 5, GFP_KERNEL);
        if (!dev_name)
                goto out_free_rawdata;
        snprintf(dev_name, len + 5, "%s%s%s:/", startsep, ipaddr, endsep);

        status = nfsd4_ssc_setup_dul(nn, ipaddr, nsui, rqstp);
        if (status)
                goto out_free_devname;
        if ((*nsui)->nsui_vfsmount)
                goto out_done;

        /* Use an 'internal' mount: SB_KERNMOUNT -> MNT_INTERNAL */
        ss_mnt = vfs_kern_mount(type, SB_KERNMOUNT, dev_name, raw_data);
        module_put(type->owner);
        if (IS_ERR(ss_mnt)) {
                status = nfserr_nodev;
                nfsd4_ssc_cancel_dul(nn, *nsui);
                goto out_free_devname;
        }
        nfsd4_ssc_update_dul(nn, *nsui, ss_mnt);
out_done:
        status = 0;

out_free_devname:
        kfree(dev_name);
out_free_rawdata:
        kfree(raw_data);
out_free_ipaddr:
        kfree(ipaddr);
out_err:
        return status;
}

/*
 * Verify COPY destination stateid.
 *
 * Connect to the source server with NFSv4.1.
 * Create the source struct file for nfsd_copy_range.
 * Called with COPY cstate:
 *    SAVED_FH: source filehandle
 *    CURRENT_FH: destination filehandle
 */
static __be32
nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
                      struct nfsd4_compound_state *cstate,
                      struct nfsd4_copy *copy)
{
        struct svc_fh *s_fh = NULL;
        stateid_t *s_stid = &copy->cp_src_stateid;
        __be32 status = nfserr_inval;

        /* Verify the destination stateid and set dst struct file*/
        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
                                            &copy->cp_dst_stateid,
                                            WR_STATE, &copy->nf_dst, NULL);
        if (status)
                goto out;

        status = nfsd4_interssc_connect(copy->cp_src, rqstp, &copy->ss_nsui);
        if (status)
                goto out;

        s_fh = &cstate->save_fh;

        copy->c_fh.size = s_fh->fh_handle.fh_size;
        memcpy(copy->c_fh.data, &s_fh->fh_handle.fh_raw, copy->c_fh.size);
        copy->stateid.seqid = cpu_to_be32(s_stid->si_generation);
        memcpy(copy->stateid.other, (void *)&s_stid->si_opaque,
               sizeof(stateid_opaque_t));

        status = 0;
out:
        return status;
}

static void
nfsd4_cleanup_inter_ssc(struct nfsd4_ssc_umount_item *nsui, struct file *filp,
                        struct nfsd_file *dst)
{
        struct nfsd_net *nn = net_generic(dst->nf_net, nfsd_net_id);
        long timeout = msecs_to_jiffies(nfsd4_ssc_umount_timeout);

        nfs42_ssc_close(filp);
        fput(filp);

        spin_lock(&nn->nfsd_ssc_lock);
        list_del(&nsui->nsui_list);
        /*
         * vfsmount can be shared by multiple exports,
         * decrement refcnt. If the count drops to 1 it
         * will be unmounted when nsui_expire expires.
         */
        refcount_dec(&nsui->nsui_refcnt);
        nsui->nsui_expire = jiffies + timeout;
        list_add_tail(&nsui->nsui_list, &nn->nfsd_ssc_mount_list);
        spin_unlock(&nn->nfsd_ssc_lock);
}

#else /* CONFIG_NFSD_V4_2_INTER_SSC */

static __be32
nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
                      struct nfsd4_compound_state *cstate,
                      struct nfsd4_copy *copy)
{
        return nfserr_inval;
}

static void
nfsd4_cleanup_inter_ssc(struct nfsd4_ssc_umount_item *nsui, struct file *filp,
                        struct nfsd_file *dst)
{
}

static struct file *nfs42_ssc_open(struct vfsmount *ss_mnt,
                                   struct nfs_fh *src_fh,
                                   nfs4_stateid *stateid)
{
        return NULL;
}
#endif /* CONFIG_NFSD_V4_2_INTER_SSC */

static __be32
nfsd4_setup_intra_ssc(struct svc_rqst *rqstp,
                      struct nfsd4_compound_state *cstate,
                      struct nfsd4_copy *copy)
{
        return nfsd4_verify_copy(rqstp, cstate, &copy->cp_src_stateid,
                                 &copy->nf_src, &copy->cp_dst_stateid,
                                 &copy->nf_dst);
}

static void nfsd4_cb_offload_release(struct nfsd4_callback *cb)
{
        struct nfsd4_cb_offload *cbo =
                container_of(cb, struct nfsd4_cb_offload, co_cb);

        kfree(cbo);
}

static int nfsd4_cb_offload_done(struct nfsd4_callback *cb,
                                 struct rpc_task *task)
{
        struct nfsd4_cb_offload *cbo =
                container_of(cb, struct nfsd4_cb_offload, co_cb);

        trace_nfsd_cb_offload_done(&cbo->co_res.cb_stateid, task);
        return 1;
}

static const struct nfsd4_callback_ops nfsd4_cb_offload_ops = {
        .release = nfsd4_cb_offload_release,
        .done = nfsd4_cb_offload_done
};

static void nfsd4_init_copy_res(struct nfsd4_copy *copy, bool sync)
{
        copy->cp_res.wr_stable_how =
                test_bit(NFSD4_COPY_F_COMMITTED, &copy->cp_flags) ?
                        NFS_FILE_SYNC : NFS_UNSTABLE;
        nfsd4_copy_set_sync(copy, sync);
        gen_boot_verifier(&copy->cp_res.wr_verifier, copy->cp_clp->net);
}

static ssize_t _nfsd_copy_file_range(struct nfsd4_copy *copy,
                                     struct file *dst,
                                     struct file *src)
{
        errseq_t since;
        ssize_t bytes_copied = 0;
        u64 bytes_total = copy->cp_count;
        u64 src_pos = copy->cp_src_pos;
        u64 dst_pos = copy->cp_dst_pos;
        int status;
        loff_t end;

        /* See RFC 7862 p.67: */
        if (bytes_total == 0)
                bytes_total = ULLONG_MAX;
        do {
                /* Only async copies can be stopped here */
                if (kthread_should_stop())
                        break;
                bytes_copied = nfsd_copy_file_range(src, src_pos, dst, dst_pos,
                                                    bytes_total);
                if (bytes_copied <= 0)
                        break;
                bytes_total -= bytes_copied;
                copy->cp_res.wr_bytes_written += bytes_copied;
                src_pos += bytes_copied;
                dst_pos += bytes_copied;
        } while (bytes_total > 0 && nfsd4_copy_is_async(copy));
        /* for a non-zero asynchronous copy do a commit of data */
        if (nfsd4_copy_is_async(copy) && copy->cp_res.wr_bytes_written > 0) {
                since = READ_ONCE(dst->f_wb_err);
                end = copy->cp_dst_pos + copy->cp_res.wr_bytes_written - 1;
                status = vfs_fsync_range(dst, copy->cp_dst_pos, end, 0);
                if (!status)
                        status = filemap_check_wb_err(dst->f_mapping, since);
                if (!status)
                        set_bit(NFSD4_COPY_F_COMMITTED, &copy->cp_flags);
        }
        return bytes_copied;
}

static __be32 nfsd4_do_copy(struct nfsd4_copy *copy,
                            struct file *src, struct file *dst,
                            bool sync)
{
        __be32 status;
        ssize_t bytes;

        bytes = _nfsd_copy_file_range(copy, dst, src);

        /* for async copy, we ignore the error, client can always retry
         * to get the error
         */
        if (bytes < 0 && !copy->cp_res.wr_bytes_written)
                status = nfserrno(bytes);
        else {
                nfsd4_init_copy_res(copy, sync);
                status = nfs_ok;
        }
        return status;
}

static void dup_copy_fields(struct nfsd4_copy *src, struct nfsd4_copy *dst)
{
        dst->cp_src_pos = src->cp_src_pos;
        dst->cp_dst_pos = src->cp_dst_pos;
        dst->cp_count = src->cp_count;
        dst->cp_flags = src->cp_flags;
        memcpy(&dst->cp_res, &src->cp_res, sizeof(src->cp_res));
        memcpy(&dst->fh, &src->fh, sizeof(src->fh));
        dst->cp_clp = src->cp_clp;
        dst->nf_dst = nfsd_file_get(src->nf_dst);
        /* for inter, nf_src doesn't exist yet */
        if (!nfsd4_ssc_is_inter(src))
                dst->nf_src = nfsd_file_get(src->nf_src);

        memcpy(&dst->cp_stateid, &src->cp_stateid, sizeof(src->cp_stateid));
        memcpy(dst->cp_src, src->cp_src, sizeof(struct nl4_server));
        memcpy(&dst->stateid, &src->stateid, sizeof(src->stateid));
        memcpy(&dst->c_fh, &src->c_fh, sizeof(src->c_fh));
        dst->ss_nsui = src->ss_nsui;
}

static void release_copy_files(struct nfsd4_copy *copy)
{
        if (copy->nf_src)
                nfsd_file_put(copy->nf_src);
        if (copy->nf_dst)
                nfsd_file_put(copy->nf_dst);
}

static void cleanup_async_copy(struct nfsd4_copy *copy)
{
        nfs4_free_copy_state(copy);
        release_copy_files(copy);
        if (copy->cp_clp) {
                spin_lock(&copy->cp_clp->async_lock);
                if (!list_empty(&copy->copies))
                        list_del_init(&copy->copies);
                spin_unlock(&copy->cp_clp->async_lock);
        }
        nfs4_put_copy(copy);
}

static void nfsd4_send_cb_offload(struct nfsd4_copy *copy, __be32 nfserr)
{
        struct nfsd4_cb_offload *cbo;

        cbo = kzalloc(sizeof(*cbo), GFP_KERNEL);
        if (!cbo)
                return;

        memcpy(&cbo->co_res, &copy->cp_res, sizeof(copy->cp_res));
        memcpy(&cbo->co_fh, &copy->fh, sizeof(copy->fh));
        cbo->co_nfserr = nfserr;

        nfsd4_init_cb(&cbo->co_cb, copy->cp_clp, &nfsd4_cb_offload_ops,
                      NFSPROC4_CLNT_CB_OFFLOAD);
        trace_nfsd_cb_offload(copy->cp_clp, &cbo->co_res.cb_stateid,
                              &cbo->co_fh, copy->cp_count, nfserr);
        nfsd4_run_cb(&cbo->co_cb);
}

/**
 * nfsd4_do_async_copy - kthread function for background server-side COPY
 * @data: arguments for COPY operation
 *
 * Return values:
 *   %0: Copy operation is done.
 */
static int nfsd4_do_async_copy(void *data)
{
        struct nfsd4_copy *copy = (struct nfsd4_copy *)data;
        __be32 nfserr;

        trace_nfsd_copy_do_async(copy);
        if (nfsd4_ssc_is_inter(copy)) {
                struct file *filp;

                filp = nfs42_ssc_open(copy->ss_nsui->nsui_vfsmount,
                                      &copy->c_fh, &copy->stateid);
                if (IS_ERR(filp)) {
                        switch (PTR_ERR(filp)) {
                        case -EBADF:
                                nfserr = nfserr_wrong_type;
                                break;
                        default:
                                nfserr = nfserr_offload_denied;
                        }
                        /* ss_mnt will be unmounted by the laundromat */
                        goto do_callback;
                }
                nfserr = nfsd4_do_copy(copy, filp, copy->nf_dst->nf_file,
                                       false);
                nfsd4_cleanup_inter_ssc(copy->ss_nsui, filp, copy->nf_dst);
        } else {
                nfserr = nfsd4_do_copy(copy, copy->nf_src->nf_file,
                                       copy->nf_dst->nf_file, false);
        }

do_callback:
        nfsd4_send_cb_offload(copy, nfserr);
        cleanup_async_copy(copy);
        return 0;
}

static __be32
nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                union nfsd4_op_u *u)
{
        struct nfsd4_copy *copy = &u->copy;
        __be32 status;
        struct nfsd4_copy *async_copy = NULL;

        copy->cp_clp = cstate->clp;
        if (nfsd4_ssc_is_inter(copy)) {
                trace_nfsd_copy_inter(copy);
                if (!inter_copy_offload_enable || nfsd4_copy_is_sync(copy)) {
                        status = nfserr_notsupp;
                        goto out;
                }
                status = nfsd4_setup_inter_ssc(rqstp, cstate, copy);
                if (status) {
                        trace_nfsd_copy_done(copy, status);
                        return nfserr_offload_denied;
                }
        } else {
                trace_nfsd_copy_intra(copy);
                status = nfsd4_setup_intra_ssc(rqstp, cstate, copy);
                if (status) {
                        trace_nfsd_copy_done(copy, status);
                        return status;
                }
        }

        memcpy(&copy->fh, &cstate->current_fh.fh_handle,
                sizeof(struct knfsd_fh));
        if (nfsd4_copy_is_async(copy)) {
                struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

                status = nfserrno(-ENOMEM);
                async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
                if (!async_copy)
                        goto out_err;
                INIT_LIST_HEAD(&async_copy->copies);
                refcount_set(&async_copy->refcount, 1);
                async_copy->cp_src = kmalloc(sizeof(*async_copy->cp_src), GFP_KERNEL);
                if (!async_copy->cp_src)
                        goto out_err;
                if (!nfs4_init_copy_state(nn, copy))
                        goto out_err;
                memcpy(&copy->cp_res.cb_stateid, &copy->cp_stateid.cs_stid,
                        sizeof(copy->cp_res.cb_stateid));
                dup_copy_fields(copy, async_copy);
                async_copy->copy_task = kthread_create(nfsd4_do_async_copy,
                                async_copy, "%s", "copy thread");
                if (IS_ERR(async_copy->copy_task))
                        goto out_err;
                spin_lock(&async_copy->cp_clp->async_lock);
                list_add(&async_copy->copies,
                                &async_copy->cp_clp->async_copies);
                spin_unlock(&async_copy->cp_clp->async_lock);
                wake_up_process(async_copy->copy_task);
                status = nfs_ok;
        } else {
                status = nfsd4_do_copy(copy, copy->nf_src->nf_file,
                                       copy->nf_dst->nf_file, true);
        }
out:
        trace_nfsd_copy_done(copy, status);
        release_copy_files(copy);
        return status;
out_err:
        if (nfsd4_ssc_is_inter(copy)) {
                /*
                 * Source's vfsmount of inter-copy will be unmounted
                 * by the laundromat. Use copy instead of async_copy
                 * since async_copy->ss_nsui might not be set yet.
                 */
                refcount_dec(&copy->ss_nsui->nsui_refcnt);
        }
        if (async_copy)
                cleanup_async_copy(async_copy);
        status = nfserrno(-ENOMEM);
        goto out;
}

static struct nfsd4_copy *
find_async_copy_locked(struct nfs4_client *clp, stateid_t *stateid)
{
        struct nfsd4_copy *copy;

        lockdep_assert_held(&clp->async_lock);

        list_for_each_entry(copy, &clp->async_copies, copies) {
                if (memcmp(&copy->cp_stateid.cs_stid, stateid, NFS4_STATEID_SIZE))
                        continue;
                return copy;
        }
        return NULL;
}

static struct nfsd4_copy *
find_async_copy(struct nfs4_client *clp, stateid_t *stateid)
{
        struct nfsd4_copy *copy;

        spin_lock(&clp->async_lock);
        copy = find_async_copy_locked(clp, stateid);
        if (copy)
                refcount_inc(&copy->refcount);
        spin_unlock(&clp->async_lock);
        return copy;
}

static __be32
nfsd4_offload_cancel(struct svc_rqst *rqstp,
                     struct nfsd4_compound_state *cstate,
                     union nfsd4_op_u *u)
{
        struct nfsd4_offload_status *os = &u->offload_status;
        struct nfsd4_copy *copy;
        struct nfs4_client *clp = cstate->clp;

        copy = find_async_copy(clp, &os->stateid);
        if (!copy) {
                struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

                return manage_cpntf_state(nn, &os->stateid, clp, NULL);
        } else
                nfsd4_stop_copy(copy);

        return nfs_ok;
}

static __be32
nfsd4_copy_notify(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                  union nfsd4_op_u *u)
{
        struct nfsd4_copy_notify *cn = &u->copy_notify;
        __be32 status;
        struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
        struct nfs4_stid *stid;
        struct nfs4_cpntf_state *cps;
        struct nfs4_client *clp = cstate->clp;

        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
                                        &cn->cpn_src_stateid, RD_STATE, NULL,
                                        &stid);
        if (status)
                return status;

        cn->cpn_lease_time.tv_sec = nn->nfsd4_lease;
        cn->cpn_lease_time.tv_nsec = 0;

        status = nfserrno(-ENOMEM);
        cps = nfs4_alloc_init_cpntf_state(nn, stid);
        if (!cps)
                goto out;
        memcpy(&cn->cpn_cnr_stateid, &cps->cp_stateid.cs_stid, sizeof(stateid_t));
        memcpy(&cps->cp_p_stateid, &stid->sc_stateid, sizeof(stateid_t));
        memcpy(&cps->cp_p_clid, &clp->cl_clientid, sizeof(clientid_t));

        /* For now, only return one server address in cpn_src, the
         * address used by the client to connect to this server.
         */
        cn->cpn_src->nl4_type = NL4_NETADDR;
        status = nfsd4_set_netaddr((struct sockaddr *)&rqstp->rq_daddr,
                                 &cn->cpn_src->u.nl4_addr);
        WARN_ON_ONCE(status);
        if (status) {
                nfs4_put_cpntf_state(nn, cps);
                goto out;
        }
out:
        nfs4_put_stid(stid);
        return status;
}

static __be32
nfsd4_fallocate(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                struct nfsd4_fallocate *fallocate, int flags)
{
        __be32 status;
        struct nfsd_file *nf;

        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
                                            &fallocate->falloc_stateid,
                                            WR_STATE, &nf, NULL);
        if (status != nfs_ok)
                return status;

        status = nfsd4_vfs_fallocate(rqstp, &cstate->current_fh, nf->nf_file,
                                     fallocate->falloc_offset,
                                     fallocate->falloc_length,
                                     flags);
        nfsd_file_put(nf);
        return status;
}

static __be32
nfsd4_offload_status(struct svc_rqst *rqstp,
                     struct nfsd4_compound_state *cstate,
                     union nfsd4_op_u *u)
{
        struct nfsd4_offload_status *os = &u->offload_status;
        __be32 status = nfs_ok;
        struct nfsd4_copy *copy;
        struct nfs4_client *clp = cstate->clp;

        spin_lock(&clp->async_lock);
        copy = find_async_copy_locked(clp, &os->stateid);
        if (copy)
                os->count = copy->cp_res.wr_bytes_written;
        else
                status = nfserr_bad_stateid;
        spin_unlock(&clp->async_lock);

        return status;
}

static __be32
nfsd4_allocate(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
               union nfsd4_op_u *u)
{
        return nfsd4_fallocate(rqstp, cstate, &u->allocate, 0);
}

static __be32
nfsd4_deallocate(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                 union nfsd4_op_u *u)
{
        return nfsd4_fallocate(rqstp, cstate, &u->deallocate,
                               FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE);
}

static __be32
nfsd4_seek(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           union nfsd4_op_u *u)
{
        struct nfsd4_seek *seek = &u->seek;
        int whence;
        __be32 status;
        struct nfsd_file *nf;

        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
                                            &seek->seek_stateid,
                                            RD_STATE, &nf, NULL);
        if (status)
                return status;

        switch (seek->seek_whence) {
        case NFS4_CONTENT_DATA:
                whence = SEEK_DATA;
                break;
        case NFS4_CONTENT_HOLE:
                whence = SEEK_HOLE;
                break;
        default:
                status = nfserr_union_notsupp;
                goto out;
        }

        /*
         * Note:  This call does change file->f_pos, but nothing in NFSD
         *        should ever file->f_pos.
         */
        seek->seek_pos = vfs_llseek(nf->nf_file, seek->seek_offset, whence);
        if (seek->seek_pos < 0)
                status = nfserrno(seek->seek_pos);
        else if (seek->seek_pos >= i_size_read(file_inode(nf->nf_file)))
                seek->seek_eof = true;

out:
        nfsd_file_put(nf);
        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;

        status = check_attr_support(rqstp, cstate, verify->ve_bmval, NULL);
        if (status)
                return status;

        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_jukebox;

        p = buf;
        status = nfsd4_encode_fattr_to_buf(&p, count, &cstate->current_fh,
                                    cstate->current_fh.fh_export,
                                    cstate->current_fh.fh_dentry,
                                    verify->ve_bmval,
                                    rqstp, 0);
        /*
         * If nfsd4_encode_fattr() ran out of space, assume that's because
         * the attributes are longer (hence different) than those given:
         */
        if (status == nfserr_resource)
                status = nfserr_not_same;
        if (status)
                goto out_kfree;

        /* skip bitmap */
        p = buf + 1 + ntohl(buf[0]);
        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,
              union nfsd4_op_u *u)
{
        __be32 status;

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

static __be32
nfsd4_verify(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
             union nfsd4_op_u *u)
{
        __be32 status;

        status = _nfsd4_verify(rqstp, cstate, &u->nverify);
        return status == nfserr_same ? nfs_ok : status;
}

#ifdef CONFIG_NFSD_PNFS
static const struct nfsd4_layout_ops *
nfsd4_layout_verify(struct svc_export *exp, unsigned int layout_type)
{
        if (!exp->ex_layout_types) {
                dprintk("%s: export does not support pNFS\n", __func__);
                return NULL;
        }

        if (layout_type >= LAYOUT_TYPE_MAX ||
            !(exp->ex_layout_types & (1 << layout_type))) {
                dprintk("%s: layout type %d not supported\n",
                        __func__, layout_type);
                return NULL;
        }

        return nfsd4_layout_ops[layout_type];
}

static __be32
nfsd4_getdeviceinfo(struct svc_rqst *rqstp,
                struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
{
        struct nfsd4_getdeviceinfo *gdp = &u->getdeviceinfo;
        const struct nfsd4_layout_ops *ops;
        struct nfsd4_deviceid_map *map;
        struct svc_export *exp;
        __be32 nfserr;

        dprintk("%s: layout_type %u dev_id [0x%llx:0x%x] maxcnt %u\n",
               __func__,
               gdp->gd_layout_type,
               gdp->gd_devid.fsid_idx, gdp->gd_devid.generation,
               gdp->gd_maxcount);

        map = nfsd4_find_devid_map(gdp->gd_devid.fsid_idx);
        if (!map) {
                dprintk("%s: couldn't find device ID to export mapping!\n",
                        __func__);
                return nfserr_noent;
        }

        exp = rqst_exp_find(rqstp, map->fsid_type, map->fsid);
        if (IS_ERR(exp)) {
                dprintk("%s: could not find device id\n", __func__);
                return nfserr_noent;
        }

        nfserr = nfserr_layoutunavailable;
        ops = nfsd4_layout_verify(exp, gdp->gd_layout_type);
        if (!ops)
                goto out;

        nfserr = nfs_ok;
        if (gdp->gd_maxcount != 0) {
                nfserr = ops->proc_getdeviceinfo(exp->ex_path.mnt->mnt_sb,
                                rqstp, cstate->clp, gdp);
        }

        gdp->gd_notify_types &= ops->notify_types;
out:
        exp_put(exp);
        return nfserr;
}

static void
nfsd4_getdeviceinfo_release(union nfsd4_op_u *u)
{
        kfree(u->getdeviceinfo.gd_device);
}

static __be32
nfsd4_layoutget(struct svc_rqst *rqstp,
                struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
{
        struct nfsd4_layoutget *lgp = &u->layoutget;
        struct svc_fh *current_fh = &cstate->current_fh;
        const struct nfsd4_layout_ops *ops;
        struct nfs4_layout_stateid *ls;
        __be32 nfserr;
        int accmode = NFSD_MAY_READ_IF_EXEC;

        switch (lgp->lg_seg.iomode) {
        case IOMODE_READ:
                accmode |= NFSD_MAY_READ;
                break;
        case IOMODE_RW:
                accmode |= NFSD_MAY_READ | NFSD_MAY_WRITE;
                break;
        default:
                dprintk("%s: invalid iomode %d\n",
                        __func__, lgp->lg_seg.iomode);
                nfserr = nfserr_badiomode;
                goto out;
        }

        nfserr = fh_verify(rqstp, current_fh, 0, accmode);
        if (nfserr)
                goto out;

        nfserr = nfserr_layoutunavailable;
        ops = nfsd4_layout_verify(current_fh->fh_export, lgp->lg_layout_type);
        if (!ops)
                goto out;

        /*
         * Verify minlength and range as per RFC5661:
         *  o  If loga_length is less than loga_minlength,
         *     the metadata server MUST return NFS4ERR_INVAL.
         *  o  If the sum of loga_offset and loga_minlength exceeds
         *     NFS4_UINT64_MAX, and loga_minlength is not
         *     NFS4_UINT64_MAX, the error NFS4ERR_INVAL MUST result.
         *  o  If the sum of loga_offset and loga_length exceeds
         *     NFS4_UINT64_MAX, and loga_length is not NFS4_UINT64_MAX,
         *     the error NFS4ERR_INVAL MUST result.
         */
        nfserr = nfserr_inval;
        if (lgp->lg_seg.length < lgp->lg_minlength ||
            (lgp->lg_minlength != NFS4_MAX_UINT64 &&
             lgp->lg_minlength > NFS4_MAX_UINT64 - lgp->lg_seg.offset) ||
            (lgp->lg_seg.length != NFS4_MAX_UINT64 &&
             lgp->lg_seg.length > NFS4_MAX_UINT64 - lgp->lg_seg.offset))
                goto out;
        if (lgp->lg_seg.length == 0)
                goto out;

        nfserr = nfsd4_preprocess_layout_stateid(rqstp, cstate, &lgp->lg_sid,
                                                true, lgp->lg_layout_type, &ls);
        if (nfserr) {
                trace_nfsd_layout_get_lookup_fail(&lgp->lg_sid);
                goto out;
        }

        nfserr = nfserr_recallconflict;
        if (atomic_read(&ls->ls_stid.sc_file->fi_lo_recalls))
                goto out_put_stid;

        nfserr = ops->proc_layoutget(d_inode(current_fh->fh_dentry),
                                     current_fh, lgp);
        if (nfserr)
                goto out_put_stid;

        nfserr = nfsd4_insert_layout(lgp, ls);

out_put_stid:
        mutex_unlock(&ls->ls_mutex);
        nfs4_put_stid(&ls->ls_stid);
out:
        return nfserr;
}

static void
nfsd4_layoutget_release(union nfsd4_op_u *u)
{
        kfree(u->layoutget.lg_content);
}

static __be32
nfsd4_layoutcommit(struct svc_rqst *rqstp,
                struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
{
        struct nfsd4_layoutcommit *lcp = &u->layoutcommit;
        const struct nfsd4_layout_seg *seg = &lcp->lc_seg;
        struct svc_fh *current_fh = &cstate->current_fh;
        const struct nfsd4_layout_ops *ops;
        loff_t new_size = lcp->lc_last_wr + 1;
        struct inode *inode;
        struct nfs4_layout_stateid *ls;
        __be32 nfserr;

        nfserr = fh_verify(rqstp, current_fh, 0, NFSD_MAY_WRITE);
        if (nfserr)
                goto out;

        nfserr = nfserr_layoutunavailable;
        ops = nfsd4_layout_verify(current_fh->fh_export, lcp->lc_layout_type);
        if (!ops)
                goto out;
        inode = d_inode(current_fh->fh_dentry);

        nfserr = nfserr_inval;
        if (new_size <= seg->offset) {
                dprintk("pnfsd: last write before layout segment\n");
                goto out;
        }
        if (new_size > seg->offset + seg->length) {
                dprintk("pnfsd: last write beyond layout segment\n");
                goto out;
        }
        if (!lcp->lc_newoffset && new_size > i_size_read(inode)) {
                dprintk("pnfsd: layoutcommit beyond EOF\n");
                goto out;
        }

        nfserr = nfsd4_preprocess_layout_stateid(rqstp, cstate, &lcp->lc_sid,
                                                false, lcp->lc_layout_type,
                                                &ls);
        if (nfserr) {
                trace_nfsd_layout_commit_lookup_fail(&lcp->lc_sid);
                /* fixup error code as per RFC5661 */
                if (nfserr == nfserr_bad_stateid)
                        nfserr = nfserr_badlayout;
                goto out;
        }

        /* LAYOUTCOMMIT does not require any serialization */
        mutex_unlock(&ls->ls_mutex);

        if (new_size > i_size_read(inode)) {
                lcp->lc_size_chg = true;
                lcp->lc_newsize = new_size;
        } else {
                lcp->lc_size_chg = false;
        }

        nfserr = ops->proc_layoutcommit(inode, lcp);
        nfs4_put_stid(&ls->ls_stid);
out:
        return nfserr;
}

static __be32
nfsd4_layoutreturn(struct svc_rqst *rqstp,
                struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
{
        struct nfsd4_layoutreturn *lrp = &u->layoutreturn;
        struct svc_fh *current_fh = &cstate->current_fh;
        __be32 nfserr;

        nfserr = fh_verify(rqstp, current_fh, 0, NFSD_MAY_NOP);
        if (nfserr)
                goto out;

        nfserr = nfserr_layoutunavailable;
        if (!nfsd4_layout_verify(current_fh->fh_export, lrp->lr_layout_type))
                goto out;

        switch (lrp->lr_seg.iomode) {
        case IOMODE_READ:
        case IOMODE_RW:
        case IOMODE_ANY:
                break;
        default:
                dprintk("%s: invalid iomode %d\n", __func__,
                        lrp->lr_seg.iomode);
                nfserr = nfserr_inval;
                goto out;
        }

        switch (lrp->lr_return_type) {
        case RETURN_FILE:
                nfserr = nfsd4_return_file_layouts(rqstp, cstate, lrp);
                break;
        case RETURN_FSID:
        case RETURN_ALL:
                nfserr = nfsd4_return_client_layouts(rqstp, cstate, lrp);
                break;
        default:
                dprintk("%s: invalid return_type %d\n", __func__,
                        lrp->lr_return_type);
                nfserr = nfserr_inval;
                break;
        }
out:
        return nfserr;
}
#endif /* CONFIG_NFSD_PNFS */

static __be32
nfsd4_getxattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
               union nfsd4_op_u *u)
{
        struct nfsd4_getxattr *getxattr = &u->getxattr;

        return nfsd_getxattr(rqstp, &cstate->current_fh,
                             getxattr->getxa_name, &getxattr->getxa_buf,
                             &getxattr->getxa_len);
}

static __be32
nfsd4_setxattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           union nfsd4_op_u *u)
{
        struct nfsd4_setxattr *setxattr = &u->setxattr;
        __be32 ret;

        if (opens_in_grace(SVC_NET(rqstp)))
                return nfserr_grace;

        ret = nfsd_setxattr(rqstp, &cstate->current_fh, setxattr->setxa_name,
                            setxattr->setxa_buf, setxattr->setxa_len,
                            setxattr->setxa_flags);

        if (!ret)
                set_change_info(&setxattr->setxa_cinfo, &cstate->current_fh);

        return ret;
}

static __be32
nfsd4_listxattrs(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           union nfsd4_op_u *u)
{
        /*
         * Get the entire list, then copy out only the user attributes
         * in the encode function.
         */
        return nfsd_listxattr(rqstp, &cstate->current_fh,
                             &u->listxattrs.lsxa_buf, &u->listxattrs.lsxa_len);
}

static __be32
nfsd4_removexattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
           union nfsd4_op_u *u)
{
        struct nfsd4_removexattr *removexattr = &u->removexattr;
        __be32 ret;

        if (opens_in_grace(SVC_NET(rqstp)))
                return nfserr_grace;

        ret = nfsd_removexattr(rqstp, &cstate->current_fh,
            removexattr->rmxa_name);

        if (!ret)
                set_change_info(&removexattr->rmxa_cinfo, &cstate->current_fh);

        return ret;
}

/*
 * NULL call.
 */
static __be32
nfsd4_proc_null(struct svc_rqst *rqstp)
{
        return rpc_success;
}

static inline void nfsd4_increment_op_stats(struct nfsd_net *nn, u32 opnum)
{
        if (opnum >= FIRST_NFS4_OP && opnum <= LAST_NFS4_OP)
                percpu_counter_inc(&nn->counter[NFSD_STATS_NFS4_OP(opnum)]);
}

static const struct nfsd4_operation nfsd4_ops[];

static const char *nfsd4_op_name(unsigned opnum);

/*
 * Enforce NFSv4.1 COMPOUND ordering rules:
 *
 * Also note, enforced elsewhere:
 *      - SEQUENCE other than as first op results in
 *        NFS4ERR_SEQUENCE_POS. (Enforced in nfsd4_sequence().)
 *      - BIND_CONN_TO_SESSION must be the only op in its compound.
 *        (Enforced in nfsd4_bind_conn_to_session().)
 *      - DESTROY_SESSION must be the final operation in a compound, if
 *        sessionid's in SEQUENCE and DESTROY_SESSION are the same.
 *        (Enforced in nfsd4_destroy_session().)
 */
static __be32 nfs41_check_op_ordering(struct nfsd4_compoundargs *args)
{
        struct nfsd4_op *first_op = &args->ops[0];

        /* These ordering requirements don't apply to NFSv4.0: */
        if (args->minorversion == 0)
                return nfs_ok;
        /* This is weird, but OK, not our problem: */
        if (args->opcnt == 0)
                return nfs_ok;
        if (first_op->status == nfserr_op_illegal)
                return nfs_ok;
        if (!(nfsd4_ops[first_op->opnum].op_flags & ALLOWED_AS_FIRST_OP))
                return nfserr_op_not_in_session;
        if (first_op->opnum == OP_SEQUENCE)
                return nfs_ok;
        /*
         * So first_op is something allowed outside a session, like
         * EXCHANGE_ID; but then it has to be the only op in the
         * compound:
         */
        if (args->opcnt != 1)
                return nfserr_not_only_op;
        return nfs_ok;
}

const struct nfsd4_operation *OPDESC(struct nfsd4_op *op)
{
        return &nfsd4_ops[op->opnum];
}

bool nfsd4_cache_this_op(struct nfsd4_op *op)
{
        if (op->opnum == OP_ILLEGAL)
                return false;
        return OPDESC(op)->op_flags & OP_CACHEME;
}

static bool need_wrongsec_check(struct svc_rqst *rqstp)
{
        struct nfsd4_compoundres *resp = rqstp->rq_resp;
        struct nfsd4_compoundargs *argp = rqstp->rq_argp;
        struct nfsd4_op *this = &argp->ops[resp->opcnt - 1];
        struct nfsd4_op *next = &argp->ops[resp->opcnt];
        const struct nfsd4_operation *thisd = OPDESC(this);
        const struct nfsd4_operation *nextd;

        /*
         * Most ops check wronsec on our own; only the putfh-like ops
         * have special rules.
         */
        if (!(thisd->op_flags & OP_IS_PUTFH_LIKE))
                return false;
        /*
         * rfc 5661 2.6.3.1.1.6: don't bother erroring out a
         * put-filehandle operation if we're not going to use the
         * result:
         */
        if (argp->opcnt == resp->opcnt)
                return false;
        if (next->opnum == OP_ILLEGAL)
                return false;
        nextd = OPDESC(next);
        /*
         * Rest of 2.6.3.1.1: certain operations will return WRONGSEC
         * errors themselves as necessary; others should check for them
         * now:
         */
        return !(nextd->op_flags & OP_HANDLES_WRONGSEC);
}

#ifdef CONFIG_NFSD_V4_2_INTER_SSC
static void
check_if_stalefh_allowed(struct nfsd4_compoundargs *args)
{
        struct nfsd4_op *op, *current_op = NULL, *saved_op = NULL;
        struct nfsd4_copy *copy;
        struct nfsd4_putfh *putfh;
        int i;

        /* traverse all operation and if it's a COPY compound, mark the
         * source filehandle to skip verification
         */
        for (i = 0; i < args->opcnt; i++) {
                op = &args->ops[i];
                if (op->opnum == OP_PUTFH)
                        current_op = op;
                else if (op->opnum == OP_SAVEFH)
                        saved_op = current_op;
                else if (op->opnum == OP_RESTOREFH)
                        current_op = saved_op;
                else if (op->opnum == OP_COPY) {
                        copy = (struct nfsd4_copy *)&op->u;
                        if (!saved_op) {
                                op->status = nfserr_nofilehandle;
                                return;
                        }
                        putfh = (struct nfsd4_putfh *)&saved_op->u;
                        if (nfsd4_ssc_is_inter(copy))
                                putfh->no_verify = true;
                }
        }
}
#else
static void
check_if_stalefh_allowed(struct nfsd4_compoundargs *args)
{
}
#endif

/*
 * COMPOUND call.
 */
static __be32
nfsd4_proc_compound(struct svc_rqst *rqstp)
{
        struct nfsd4_compoundargs *args = rqstp->rq_argp;
        struct nfsd4_compoundres *resp = rqstp->rq_resp;
        struct nfsd4_op *op;
        struct nfsd4_compound_state *cstate = &resp->cstate;
        struct svc_fh *current_fh = &cstate->current_fh;
        struct svc_fh *save_fh = &cstate->save_fh;
        struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
        __be32          status;

        resp->xdr = &rqstp->rq_res_stream;
        resp->statusp = resp->xdr->p;

        /* reserve space for: NFS status code */
        xdr_reserve_space(resp->xdr, XDR_UNIT);

        /* reserve space for: taglen, tag, and opcnt */
        xdr_reserve_space(resp->xdr, XDR_UNIT * 2 + args->taglen);
        resp->taglen = args->taglen;
        resp->tag = args->tag;
        resp->rqstp = rqstp;
        cstate->minorversion = args->minorversion;
        fh_init(current_fh, NFS4_FHSIZE);
        fh_init(save_fh, NFS4_FHSIZE);
        /*
         * Don't use the deferral mechanism for NFSv4; compounds make it
         * too hard to avoid non-idempotency problems.
         */
        clear_bit(RQ_USEDEFERRAL, &rqstp->rq_flags);

        /*
         * According to RFC3010, this takes precedence over all other errors.
         */
        status = nfserr_minor_vers_mismatch;
        if (nfsd_minorversion(nn, args->minorversion, NFSD_TEST) <= 0)
                goto out;

        status = nfs41_check_op_ordering(args);
        if (status) {
                op = &args->ops[0];
                op->status = status;
                resp->opcnt = 1;
                goto encode_op;
        }
        check_if_stalefh_allowed(args);

        rqstp->rq_lease_breaker = (void **)&cstate->clp;

        trace_nfsd_compound(rqstp, args->tag, args->taglen, args->client_opcnt);
        while (!status && resp->opcnt < args->opcnt) {
                op = &args->ops[resp->opcnt++];

                if (unlikely(resp->opcnt == NFSD_MAX_OPS_PER_COMPOUND)) {
                        /* If there are still more operations to process,
                         * stop here and report NFS4ERR_RESOURCE. */
                        if (cstate->minorversion == 0 &&
                            args->client_opcnt > resp->opcnt) {
                                op->status = nfserr_resource;
                                goto encode_op;
                        }
                }

                /*
                 * 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) {
                        if (op->opnum == OP_OPEN)
                                op->status = nfsd4_open_omfg(rqstp, cstate, op);
                        goto encode_op;
                }
                if (!current_fh->fh_dentry &&
                                !HAS_FH_FLAG(current_fh, NFSD4_FH_FOREIGN)) {
                        if (!(op->opdesc->op_flags & ALLOWED_WITHOUT_FH)) {
                                op->status = nfserr_nofilehandle;
                                goto encode_op;
                        }
                } else if (current_fh->fh_export &&
                           current_fh->fh_export->ex_fslocs.migrated &&
                          !(op->opdesc->op_flags & ALLOWED_ON_ABSENT_FS)) {
                        op->status = nfserr_moved;
                        goto encode_op;
                }

                fh_clear_pre_post_attrs(current_fh);

                /* If op is non-idempotent */
                if (op->opdesc->op_flags & OP_MODIFIES_SOMETHING) {
                        /*
                         * Don't execute this op if we couldn't encode a
                         * successful reply:
                         */
                        u32 plen = op->opdesc->op_rsize_bop(rqstp, op);
                        /*
                         * Plus if there's another operation, make sure
                         * we'll have space to at least encode an error:
                         */
                        if (resp->opcnt < args->opcnt)
                                plen += COMPOUND_ERR_SLACK_SPACE;
                        op->status = nfsd4_check_resp_size(resp, plen);
                }

                if (op->status)
                        goto encode_op;

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

                /* Only from SEQUENCE */
                if (cstate->status == nfserr_replay_cache) {
                        dprintk("%s NFS4.1 replay from cache\n", __func__);
                        status = op->status;
                        goto out;
                }
                if (!op->status) {
                        if (op->opdesc->op_set_currentstateid)
                                op->opdesc->op_set_currentstateid(cstate, &op->u);

                        if (op->opdesc->op_flags & OP_CLEAR_STATEID)
                                clear_current_stateid(cstate);

                        if (current_fh->fh_export &&
                                        need_wrongsec_check(rqstp))
                                op->status = check_nfsd_access(current_fh->fh_export, rqstp);
                }
encode_op:
                if (op->status == nfserr_replay_me) {
                        op->replay = &cstate->replay_owner->so_replay;
                        nfsd4_encode_replay(resp->xdr, op);
                        status = op->status = op->replay->rp_status;
                } else {
                        nfsd4_encode_operation(resp, op);
                        status = op->status;
                }

                trace_nfsd_compound_status(args->client_opcnt, resp->opcnt,
                                           status, nfsd4_op_name(op->opnum));

                nfsd4_cstate_clear_replay(cstate);
                nfsd4_increment_op_stats(nn, op->opnum);
        }

        fh_put(current_fh);
        fh_put(save_fh);
        BUG_ON(cstate->replay_owner);
out:
        cstate->status = status;
        /* Reset deferral mechanism for RPC deferrals */
        set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags);
        return rpc_success;
}

#define op_encode_hdr_size              (2)
#define op_encode_stateid_maxsz         (XDR_QUADLEN(NFS4_STATEID_SIZE))
#define op_encode_verifier_maxsz        (XDR_QUADLEN(NFS4_VERIFIER_SIZE))
#define op_encode_change_info_maxsz     (5)
#define nfs4_fattr_bitmap_maxsz         (4)

/* We'll fall back on returning no lockowner if run out of space: */
#define op_encode_lockowner_maxsz       (0)
#define op_encode_lock_denied_maxsz     (8 + op_encode_lockowner_maxsz)

#define nfs4_owner_maxsz                (1 + XDR_QUADLEN(IDMAP_NAMESZ))

#define op_encode_ace_maxsz             (3 + nfs4_owner_maxsz)
#define op_encode_delegation_maxsz      (1 + op_encode_stateid_maxsz + 1 + \
                                         op_encode_ace_maxsz)

#define op_encode_channel_attrs_maxsz   (6 + 1 + 1)

/*
 * The _rsize() helpers are invoked by the NFSv4 COMPOUND decoder, which
 * is called before sunrpc sets rq_res.buflen. Thus we have to compute
 * the maximum payload size here, based on transport limits and the size
 * of the remaining space in the rq_pages array.
 */
static u32 nfsd4_max_payload(const struct svc_rqst *rqstp)
{
        u32 buflen;

        buflen = (rqstp->rq_page_end - rqstp->rq_next_page) * PAGE_SIZE;
        buflen -= rqstp->rq_auth_slack;
        buflen -= rqstp->rq_res.head[0].iov_len;
        return min_t(u32, buflen, svc_max_payload(rqstp));
}

static u32 nfsd4_only_status_rsize(const struct svc_rqst *rqstp,
                                   const struct nfsd4_op *op)
{
        return (op_encode_hdr_size) * sizeof(__be32);
}

static u32 nfsd4_status_stateid_rsize(const struct svc_rqst *rqstp,
                                      const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_stateid_maxsz)* sizeof(__be32);
}

static u32 nfsd4_access_rsize(const struct svc_rqst *rqstp,
                              const struct nfsd4_op *op)
{
        /* ac_supported, ac_resp_access */
        return (op_encode_hdr_size + 2)* sizeof(__be32);
}

static u32 nfsd4_commit_rsize(const struct svc_rqst *rqstp,
                              const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_verifier_maxsz) * sizeof(__be32);
}

static u32 nfsd4_create_rsize(const struct svc_rqst *rqstp,
                              const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_change_info_maxsz
                + nfs4_fattr_bitmap_maxsz) * sizeof(__be32);
}

/*
 * Note since this is an idempotent operation we won't insist on failing
 * the op prematurely if the estimate is too large.  We may turn off splice
 * reads unnecessarily.
 */
static u32 nfsd4_getattr_rsize(const struct svc_rqst *rqstp,
                               const struct nfsd4_op *op)
{
        const u32 *bmap = op->u.getattr.ga_bmval;
        u32 bmap0 = bmap[0], bmap1 = bmap[1], bmap2 = bmap[2];
        u32 ret = 0;

        if (bmap0 & FATTR4_WORD0_ACL)
                return nfsd4_max_payload(rqstp);
        if (bmap0 & FATTR4_WORD0_FS_LOCATIONS)
                return nfsd4_max_payload(rqstp);

        if (bmap1 & FATTR4_WORD1_OWNER) {
                ret += IDMAP_NAMESZ + 4;
                bmap1 &= ~FATTR4_WORD1_OWNER;
        }
        if (bmap1 & FATTR4_WORD1_OWNER_GROUP) {
                ret += IDMAP_NAMESZ + 4;
                bmap1 &= ~FATTR4_WORD1_OWNER_GROUP;
        }
        if (bmap0 & FATTR4_WORD0_FILEHANDLE) {
                ret += NFS4_FHSIZE + 4;
                bmap0 &= ~FATTR4_WORD0_FILEHANDLE;
        }
        if (bmap2 & FATTR4_WORD2_SECURITY_LABEL) {
                ret += NFS4_MAXLABELLEN + 12;
                bmap2 &= ~FATTR4_WORD2_SECURITY_LABEL;
        }
        /*
         * Largest of remaining attributes are 16 bytes (e.g.,
         * supported_attributes)
         */
        ret += 16 * (hweight32(bmap0) + hweight32(bmap1) + hweight32(bmap2));
        /* bitmask, length */
        ret += 20;
        return ret;
}

static u32 nfsd4_getfh_rsize(const struct svc_rqst *rqstp,
                             const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + 1) * sizeof(__be32) + NFS4_FHSIZE;
}

static u32 nfsd4_link_rsize(const struct svc_rqst *rqstp,
                            const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_change_info_maxsz)
                * sizeof(__be32);
}

static u32 nfsd4_lock_rsize(const struct svc_rqst *rqstp,
                            const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_lock_denied_maxsz)
                * sizeof(__be32);
}

static u32 nfsd4_open_rsize(const struct svc_rqst *rqstp,
                            const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_stateid_maxsz
                + op_encode_change_info_maxsz + 1
                + nfs4_fattr_bitmap_maxsz
                + op_encode_delegation_maxsz) * sizeof(__be32);
}

static u32 nfsd4_read_rsize(const struct svc_rqst *rqstp,
                            const struct nfsd4_op *op)
{
        u32 rlen = min(op->u.read.rd_length, nfsd4_max_payload(rqstp));

        return (op_encode_hdr_size + 2 + XDR_QUADLEN(rlen)) * sizeof(__be32);
}

static u32 nfsd4_read_plus_rsize(const struct svc_rqst *rqstp,
                                 const struct nfsd4_op *op)
{
        u32 rlen = min(op->u.read.rd_length, nfsd4_max_payload(rqstp));
        /*
         * If we detect that the file changed during hole encoding, then we
         * recover by encoding the remaining reply as data. This means we need
         * to set aside enough room to encode two data segments.
         */
        u32 seg_len = 2 * (1 + 2 + 1);

        return (op_encode_hdr_size + 2 + seg_len + XDR_QUADLEN(rlen)) * sizeof(__be32);
}

static u32 nfsd4_readdir_rsize(const struct svc_rqst *rqstp,
                               const struct nfsd4_op *op)
{
        u32 rlen = min(op->u.readdir.rd_maxcount, nfsd4_max_payload(rqstp));

        return (op_encode_hdr_size + op_encode_verifier_maxsz +
                XDR_QUADLEN(rlen)) * sizeof(__be32);
}

static u32 nfsd4_readlink_rsize(const struct svc_rqst *rqstp,
                                const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + 1) * sizeof(__be32) + PAGE_SIZE;
}

static u32 nfsd4_remove_rsize(const struct svc_rqst *rqstp,
                              const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_change_info_maxsz)
                * sizeof(__be32);
}

static u32 nfsd4_rename_rsize(const struct svc_rqst *rqstp,
                              const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_change_info_maxsz
                + op_encode_change_info_maxsz) * sizeof(__be32);
}

static u32 nfsd4_sequence_rsize(const struct svc_rqst *rqstp,
                                const struct nfsd4_op *op)
{
        return (op_encode_hdr_size
                + XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + 5) * sizeof(__be32);
}

static u32 nfsd4_test_stateid_rsize(const struct svc_rqst *rqstp,
                                    const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + 1 + op->u.test_stateid.ts_num_ids)
                * sizeof(__be32);
}

static u32 nfsd4_setattr_rsize(const struct svc_rqst *rqstp,
                               const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + nfs4_fattr_bitmap_maxsz) * sizeof(__be32);
}

static u32 nfsd4_secinfo_rsize(const struct svc_rqst *rqstp,
                               const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + RPC_AUTH_MAXFLAVOR *
                (4 + XDR_QUADLEN(GSS_OID_MAX_LEN))) * sizeof(__be32);
}

static u32 nfsd4_setclientid_rsize(const struct svc_rqst *rqstp,
                                   const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + 2 + XDR_QUADLEN(NFS4_VERIFIER_SIZE)) *
                                                                sizeof(__be32);
}

static u32 nfsd4_write_rsize(const struct svc_rqst *rqstp,
                             const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + 2 + op_encode_verifier_maxsz) * sizeof(__be32);
}

static u32 nfsd4_exchange_id_rsize(const struct svc_rqst *rqstp,
                                   const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + 2 + 1 + /* eir_clientid, eir_sequenceid */\
                1 + 1 + /* eir_flags, spr_how */\
                4 + /* spo_must_enforce & _allow with bitmap */\
                2 + /*eir_server_owner.so_minor_id */\
                /* eir_server_owner.so_major_id<> */\
                XDR_QUADLEN(NFS4_OPAQUE_LIMIT) + 1 +\
                /* eir_server_scope<> */\
                XDR_QUADLEN(NFS4_OPAQUE_LIMIT) + 1 +\
                1 + /* eir_server_impl_id array length */\
                0 /* ignored eir_server_impl_id contents */) * sizeof(__be32);
}

static u32 nfsd4_bind_conn_to_session_rsize(const struct svc_rqst *rqstp,
                                            const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + \
                XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + /* bctsr_sessid */\
                2 /* bctsr_dir, use_conn_in_rdma_mode */) * sizeof(__be32);
}

static u32 nfsd4_create_session_rsize(const struct svc_rqst *rqstp,
                                      const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + \
                XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + /* sessionid */\
                2 + /* csr_sequence, csr_flags */\
                op_encode_channel_attrs_maxsz + \
                op_encode_channel_attrs_maxsz) * sizeof(__be32);
}

static u32 nfsd4_copy_rsize(const struct svc_rqst *rqstp,
                            const struct nfsd4_op *op)
{
        return (op_encode_hdr_size +
                1 /* wr_callback */ +
                op_encode_stateid_maxsz /* wr_callback */ +
                2 /* wr_count */ +
                1 /* wr_committed */ +
                op_encode_verifier_maxsz +
                1 /* cr_consecutive */ +
                1 /* cr_synchronous */) * sizeof(__be32);
}

static u32 nfsd4_offload_status_rsize(const struct svc_rqst *rqstp,
                                      const struct nfsd4_op *op)
{
        return (op_encode_hdr_size +
                2 /* osr_count */ +
                1 /* osr_complete<1> optional 0 for now */) * sizeof(__be32);
}

static u32 nfsd4_copy_notify_rsize(const struct svc_rqst *rqstp,
                                   const struct nfsd4_op *op)
{
        return (op_encode_hdr_size +
                3 /* cnr_lease_time */ +
                1 /* We support one cnr_source_server */ +
                1 /* cnr_stateid seq */ +
                op_encode_stateid_maxsz /* cnr_stateid */ +
                1 /* num cnr_source_server*/ +
                1 /* nl4_type */ +
                1 /* nl4 size */ +
                XDR_QUADLEN(NFS4_OPAQUE_LIMIT) /*nl4_loc + nl4_loc_sz */)
                * sizeof(__be32);
}

#ifdef CONFIG_NFSD_PNFS
static u32 nfsd4_getdeviceinfo_rsize(const struct svc_rqst *rqstp,
                                     const struct nfsd4_op *op)
{
        u32 rlen = min(op->u.getdeviceinfo.gd_maxcount, nfsd4_max_payload(rqstp));

        return (op_encode_hdr_size +
                1 /* gd_layout_type*/ +
                XDR_QUADLEN(rlen) +
                2 /* gd_notify_types */) * sizeof(__be32);
}

/*
 * At this stage we don't really know what layout driver will handle the request,
 * so we need to define an arbitrary upper bound here.
 */
#define MAX_LAYOUT_SIZE         128
static u32 nfsd4_layoutget_rsize(const struct svc_rqst *rqstp,
                                 const struct nfsd4_op *op)
{
        return (op_encode_hdr_size +
                1 /* logr_return_on_close */ +
                op_encode_stateid_maxsz +
                1 /* nr of layouts */ +
                MAX_LAYOUT_SIZE) * sizeof(__be32);
}

static u32 nfsd4_layoutcommit_rsize(const struct svc_rqst *rqstp,
                                    const struct nfsd4_op *op)
{
        return (op_encode_hdr_size +
                1 /* locr_newsize */ +
                2 /* ns_size */) * sizeof(__be32);
}

static u32 nfsd4_layoutreturn_rsize(const struct svc_rqst *rqstp,
                                    const struct nfsd4_op *op)
{
        return (op_encode_hdr_size +
                1 /* lrs_stateid */ +
                op_encode_stateid_maxsz) * sizeof(__be32);
}
#endif /* CONFIG_NFSD_PNFS */


static u32 nfsd4_seek_rsize(const struct svc_rqst *rqstp,
                            const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + 3) * sizeof(__be32);
}

static u32 nfsd4_getxattr_rsize(const struct svc_rqst *rqstp,
                                const struct nfsd4_op *op)
{
        u32 rlen = min_t(u32, XATTR_SIZE_MAX, nfsd4_max_payload(rqstp));

        return (op_encode_hdr_size + 1 + XDR_QUADLEN(rlen)) * sizeof(__be32);
}

static u32 nfsd4_setxattr_rsize(const struct svc_rqst *rqstp,
                                const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_change_info_maxsz)
                * sizeof(__be32);
}
static u32 nfsd4_listxattrs_rsize(const struct svc_rqst *rqstp,
                                  const struct nfsd4_op *op)
{
        u32 rlen = min(op->u.listxattrs.lsxa_maxcount, nfsd4_max_payload(rqstp));

        return (op_encode_hdr_size + 4 + XDR_QUADLEN(rlen)) * sizeof(__be32);
}

static u32 nfsd4_removexattr_rsize(const struct svc_rqst *rqstp,
                                   const struct nfsd4_op *op)
{
        return (op_encode_hdr_size + op_encode_change_info_maxsz)
                * sizeof(__be32);
}


static const struct nfsd4_operation nfsd4_ops[] = {
        [OP_ACCESS] = {
                .op_func = nfsd4_access,
                .op_name = "OP_ACCESS",
                .op_rsize_bop = nfsd4_access_rsize,
        },
        [OP_CLOSE] = {
                .op_func = nfsd4_close,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_CLOSE",
                .op_rsize_bop = nfsd4_status_stateid_rsize,
                .op_get_currentstateid = nfsd4_get_closestateid,
                .op_set_currentstateid = nfsd4_set_closestateid,
        },
        [OP_COMMIT] = {
                .op_func = nfsd4_commit,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_COMMIT",
                .op_rsize_bop = nfsd4_commit_rsize,
        },
        [OP_CREATE] = {
                .op_func = nfsd4_create,
                .op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME | OP_CLEAR_STATEID,
                .op_name = "OP_CREATE",
                .op_rsize_bop = nfsd4_create_rsize,
        },
        [OP_DELEGRETURN] = {
                .op_func = nfsd4_delegreturn,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_DELEGRETURN",
                .op_rsize_bop = nfsd4_only_status_rsize,
                .op_get_currentstateid = nfsd4_get_delegreturnstateid,
        },
        [OP_GETATTR] = {
                .op_func = nfsd4_getattr,
                .op_flags = ALLOWED_ON_ABSENT_FS,
                .op_rsize_bop = nfsd4_getattr_rsize,
                .op_name = "OP_GETATTR",
        },
        [OP_GETFH] = {
                .op_func = nfsd4_getfh,
                .op_name = "OP_GETFH",
                .op_rsize_bop = nfsd4_getfh_rsize,
        },
        [OP_LINK] = {
                .op_func = nfsd4_link,
                .op_flags = ALLOWED_ON_ABSENT_FS | OP_MODIFIES_SOMETHING
                                | OP_CACHEME,
                .op_name = "OP_LINK",
                .op_rsize_bop = nfsd4_link_rsize,
        },
        [OP_LOCK] = {
                .op_func = nfsd4_lock,
                .op_release = nfsd4_lock_release,
                .op_flags = OP_MODIFIES_SOMETHING |
                                OP_NONTRIVIAL_ERROR_ENCODE,
                .op_name = "OP_LOCK",
                .op_rsize_bop = nfsd4_lock_rsize,
                .op_set_currentstateid = nfsd4_set_lockstateid,
        },
        [OP_LOCKT] = {
                .op_func = nfsd4_lockt,
                .op_release = nfsd4_lockt_release,
                .op_flags = OP_NONTRIVIAL_ERROR_ENCODE,
                .op_name = "OP_LOCKT",
                .op_rsize_bop = nfsd4_lock_rsize,
        },
        [OP_LOCKU] = {
                .op_func = nfsd4_locku,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_LOCKU",
                .op_rsize_bop = nfsd4_status_stateid_rsize,
                .op_get_currentstateid = nfsd4_get_lockustateid,
        },
        [OP_LOOKUP] = {
                .op_func = nfsd4_lookup,
                .op_flags = OP_HANDLES_WRONGSEC | OP_CLEAR_STATEID,
                .op_name = "OP_LOOKUP",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_LOOKUPP] = {
                .op_func = nfsd4_lookupp,
                .op_flags = OP_HANDLES_WRONGSEC | OP_CLEAR_STATEID,
                .op_name = "OP_LOOKUPP",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_NVERIFY] = {
                .op_func = nfsd4_nverify,
                .op_name = "OP_NVERIFY",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_OPEN] = {
                .op_func = nfsd4_open,
                .op_flags = OP_HANDLES_WRONGSEC | OP_MODIFIES_SOMETHING,
                .op_name = "OP_OPEN",
                .op_rsize_bop = nfsd4_open_rsize,
                .op_set_currentstateid = nfsd4_set_openstateid,
        },
        [OP_OPEN_CONFIRM] = {
                .op_func = nfsd4_open_confirm,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_OPEN_CONFIRM",
                .op_rsize_bop = nfsd4_status_stateid_rsize,
        },
        [OP_OPEN_DOWNGRADE] = {
                .op_func = nfsd4_open_downgrade,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_OPEN_DOWNGRADE",
                .op_rsize_bop = nfsd4_status_stateid_rsize,
                .op_get_currentstateid = nfsd4_get_opendowngradestateid,
                .op_set_currentstateid = nfsd4_set_opendowngradestateid,
        },
        [OP_PUTFH] = {
                .op_func = nfsd4_putfh,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS
                                | OP_IS_PUTFH_LIKE | OP_CLEAR_STATEID,
                .op_name = "OP_PUTFH",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_PUTPUBFH] = {
                .op_func = nfsd4_putrootfh,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS
                                | OP_IS_PUTFH_LIKE | OP_CLEAR_STATEID,
                .op_name = "OP_PUTPUBFH",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_PUTROOTFH] = {
                .op_func = nfsd4_putrootfh,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS
                                | OP_IS_PUTFH_LIKE | OP_CLEAR_STATEID,
                .op_name = "OP_PUTROOTFH",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_READ] = {
                .op_func = nfsd4_read,
                .op_release = nfsd4_read_release,
                .op_name = "OP_READ",
                .op_rsize_bop = nfsd4_read_rsize,
                .op_get_currentstateid = nfsd4_get_readstateid,
        },
        [OP_READDIR] = {
                .op_func = nfsd4_readdir,
                .op_name = "OP_READDIR",
                .op_rsize_bop = nfsd4_readdir_rsize,
        },
        [OP_READLINK] = {
                .op_func = nfsd4_readlink,
                .op_name = "OP_READLINK",
                .op_rsize_bop = nfsd4_readlink_rsize,
        },
        [OP_REMOVE] = {
                .op_func = nfsd4_remove,
                .op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
                .op_name = "OP_REMOVE",
                .op_rsize_bop = nfsd4_remove_rsize,
        },
        [OP_RENAME] = {
                .op_func = nfsd4_rename,
                .op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
                .op_name = "OP_RENAME",
                .op_rsize_bop = nfsd4_rename_rsize,
        },
        [OP_RENEW] = {
                .op_func = nfsd4_renew,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS
                                | OP_MODIFIES_SOMETHING,
                .op_name = "OP_RENEW",
                .op_rsize_bop = nfsd4_only_status_rsize,

        },
        [OP_RESTOREFH] = {
                .op_func = nfsd4_restorefh,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS
                                | OP_IS_PUTFH_LIKE | OP_MODIFIES_SOMETHING,
                .op_name = "OP_RESTOREFH",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_SAVEFH] = {
                .op_func = nfsd4_savefh,
                .op_flags = OP_HANDLES_WRONGSEC | OP_MODIFIES_SOMETHING,
                .op_name = "OP_SAVEFH",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_SECINFO] = {
                .op_func = nfsd4_secinfo,
                .op_release = nfsd4_secinfo_release,
                .op_flags = OP_HANDLES_WRONGSEC,
                .op_name = "OP_SECINFO",
                .op_rsize_bop = nfsd4_secinfo_rsize,
        },
        [OP_SETATTR] = {
                .op_func = nfsd4_setattr,
                .op_name = "OP_SETATTR",
                .op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME
                                | OP_NONTRIVIAL_ERROR_ENCODE,
                .op_rsize_bop = nfsd4_setattr_rsize,
                .op_get_currentstateid = nfsd4_get_setattrstateid,
        },
        [OP_SETCLIENTID] = {
                .op_func = nfsd4_setclientid,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS
                                | OP_MODIFIES_SOMETHING | OP_CACHEME
                                | OP_NONTRIVIAL_ERROR_ENCODE,
                .op_name = "OP_SETCLIENTID",
                .op_rsize_bop = nfsd4_setclientid_rsize,
        },
        [OP_SETCLIENTID_CONFIRM] = {
                .op_func = nfsd4_setclientid_confirm,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS
                                | OP_MODIFIES_SOMETHING | OP_CACHEME,
                .op_name = "OP_SETCLIENTID_CONFIRM",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_VERIFY] = {
                .op_func = nfsd4_verify,
                .op_name = "OP_VERIFY",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_WRITE] = {
                .op_func = nfsd4_write,
                .op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
                .op_name = "OP_WRITE",
                .op_rsize_bop = nfsd4_write_rsize,
                .op_get_currentstateid = nfsd4_get_writestateid,
        },
        [OP_RELEASE_LOCKOWNER] = {
                .op_func = nfsd4_release_lockowner,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS
                                | OP_MODIFIES_SOMETHING,
                .op_name = "OP_RELEASE_LOCKOWNER",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },

        /* NFSv4.1 operations */
        [OP_EXCHANGE_ID] = {
                .op_func = nfsd4_exchange_id,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP
                                | OP_MODIFIES_SOMETHING,
                .op_name = "OP_EXCHANGE_ID",
                .op_rsize_bop = nfsd4_exchange_id_rsize,
        },
        [OP_BACKCHANNEL_CTL] = {
                .op_func = nfsd4_backchannel_ctl,
                .op_flags = ALLOWED_WITHOUT_FH | OP_MODIFIES_SOMETHING,
                .op_name = "OP_BACKCHANNEL_CTL",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_BIND_CONN_TO_SESSION] = {
                .op_func = nfsd4_bind_conn_to_session,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP
                                | OP_MODIFIES_SOMETHING,
                .op_name = "OP_BIND_CONN_TO_SESSION",
                .op_rsize_bop = nfsd4_bind_conn_to_session_rsize,
        },
        [OP_CREATE_SESSION] = {
                .op_func = nfsd4_create_session,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP
                                | OP_MODIFIES_SOMETHING,
                .op_name = "OP_CREATE_SESSION",
                .op_rsize_bop = nfsd4_create_session_rsize,
        },
        [OP_DESTROY_SESSION] = {
                .op_func = nfsd4_destroy_session,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP
                                | OP_MODIFIES_SOMETHING,
                .op_name = "OP_DESTROY_SESSION",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_SEQUENCE] = {
                .op_func = nfsd4_sequence,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
                .op_name = "OP_SEQUENCE",
                .op_rsize_bop = nfsd4_sequence_rsize,
        },
        [OP_DESTROY_CLIENTID] = {
                .op_func = nfsd4_destroy_clientid,
                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP
                                | OP_MODIFIES_SOMETHING,
                .op_name = "OP_DESTROY_CLIENTID",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_RECLAIM_COMPLETE] = {
                .op_func = nfsd4_reclaim_complete,
                .op_flags = ALLOWED_WITHOUT_FH | OP_MODIFIES_SOMETHING,
                .op_name = "OP_RECLAIM_COMPLETE",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_SECINFO_NO_NAME] = {
                .op_func = nfsd4_secinfo_no_name,
                .op_release = nfsd4_secinfo_no_name_release,
                .op_flags = OP_HANDLES_WRONGSEC,
                .op_name = "OP_SECINFO_NO_NAME",
                .op_rsize_bop = nfsd4_secinfo_rsize,
        },
        [OP_TEST_STATEID] = {
                .op_func = nfsd4_test_stateid,
                .op_flags = ALLOWED_WITHOUT_FH,
                .op_name = "OP_TEST_STATEID",
                .op_rsize_bop = nfsd4_test_stateid_rsize,
        },
        [OP_FREE_STATEID] = {
                .op_func = nfsd4_free_stateid,
                .op_flags = ALLOWED_WITHOUT_FH | OP_MODIFIES_SOMETHING,
                .op_name = "OP_FREE_STATEID",
                .op_get_currentstateid = nfsd4_get_freestateid,
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
#ifdef CONFIG_NFSD_PNFS
        [OP_GETDEVICEINFO] = {
                .op_func = nfsd4_getdeviceinfo,
                .op_release = nfsd4_getdeviceinfo_release,
                .op_flags = ALLOWED_WITHOUT_FH,
                .op_name = "OP_GETDEVICEINFO",
                .op_rsize_bop = nfsd4_getdeviceinfo_rsize,
        },
        [OP_LAYOUTGET] = {
                .op_func = nfsd4_layoutget,
                .op_release = nfsd4_layoutget_release,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_LAYOUTGET",
                .op_rsize_bop = nfsd4_layoutget_rsize,
        },
        [OP_LAYOUTCOMMIT] = {
                .op_func = nfsd4_layoutcommit,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_LAYOUTCOMMIT",
                .op_rsize_bop = nfsd4_layoutcommit_rsize,
        },
        [OP_LAYOUTRETURN] = {
                .op_func = nfsd4_layoutreturn,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_LAYOUTRETURN",
                .op_rsize_bop = nfsd4_layoutreturn_rsize,
        },
#endif /* CONFIG_NFSD_PNFS */

        /* NFSv4.2 operations */
        [OP_ALLOCATE] = {
                .op_func = nfsd4_allocate,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_ALLOCATE",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_DEALLOCATE] = {
                .op_func = nfsd4_deallocate,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_DEALLOCATE",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_CLONE] = {
                .op_func = nfsd4_clone,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_CLONE",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_COPY] = {
                .op_func = nfsd4_copy,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_COPY",
                .op_rsize_bop = nfsd4_copy_rsize,
        },
        [OP_READ_PLUS] = {
                .op_func = nfsd4_read,
                .op_release = nfsd4_read_release,
                .op_name = "OP_READ_PLUS",
                .op_rsize_bop = nfsd4_read_plus_rsize,
                .op_get_currentstateid = nfsd4_get_readstateid,
        },
        [OP_SEEK] = {
                .op_func = nfsd4_seek,
                .op_name = "OP_SEEK",
                .op_rsize_bop = nfsd4_seek_rsize,
        },
        [OP_OFFLOAD_STATUS] = {
                .op_func = nfsd4_offload_status,
                .op_name = "OP_OFFLOAD_STATUS",
                .op_rsize_bop = nfsd4_offload_status_rsize,
        },
        [OP_OFFLOAD_CANCEL] = {
                .op_func = nfsd4_offload_cancel,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_OFFLOAD_CANCEL",
                .op_rsize_bop = nfsd4_only_status_rsize,
        },
        [OP_COPY_NOTIFY] = {
                .op_func = nfsd4_copy_notify,
                .op_flags = OP_MODIFIES_SOMETHING,
                .op_name = "OP_COPY_NOTIFY",
                .op_rsize_bop = nfsd4_copy_notify_rsize,
        },
        [OP_GETXATTR] = {
                .op_func = nfsd4_getxattr,
                .op_name = "OP_GETXATTR",
                .op_rsize_bop = nfsd4_getxattr_rsize,
        },
        [OP_SETXATTR] = {
                .op_func = nfsd4_setxattr,
                .op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
                .op_name = "OP_SETXATTR",
                .op_rsize_bop = nfsd4_setxattr_rsize,
        },
        [OP_LISTXATTRS] = {
                .op_func = nfsd4_listxattrs,
                .op_name = "OP_LISTXATTRS",
                .op_rsize_bop = nfsd4_listxattrs_rsize,
        },
        [OP_REMOVEXATTR] = {
                .op_func = nfsd4_removexattr,
                .op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
                .op_name = "OP_REMOVEXATTR",
                .op_rsize_bop = nfsd4_removexattr_rsize,
        },
};

/**
 * nfsd4_spo_must_allow - Determine if the compound op contains an
 * operation that is allowed to be sent with machine credentials
 *
 * @rqstp: a pointer to the struct svc_rqst
 *
 * Checks to see if the compound contains a spo_must_allow op
 * and confirms that it was sent with the proper machine creds.
 */

bool nfsd4_spo_must_allow(struct svc_rqst *rqstp)
{
        struct nfsd4_compoundres *resp = rqstp->rq_resp;
        struct nfsd4_compoundargs *argp = rqstp->rq_argp;
        struct nfsd4_op *this;
        struct nfsd4_compound_state *cstate = &resp->cstate;
        struct nfs4_op_map *allow = &cstate->clp->cl_spo_must_allow;
        u32 opiter;

        if (!cstate->minorversion)
                return false;

        if (cstate->spo_must_allowed)
                return true;

        opiter = resp->opcnt;
        while (opiter < argp->opcnt) {
                this = &argp->ops[opiter++];
                if (test_bit(this->opnum, allow->u.longs) &&
                        cstate->clp->cl_mach_cred &&
                        nfsd4_mach_creds_match(cstate->clp, rqstp)) {
                        cstate->spo_must_allowed = true;
                        return true;
                }
        }
        cstate->spo_must_allowed = false;
        return false;
}

int nfsd4_max_reply(struct svc_rqst *rqstp, struct nfsd4_op *op)
{
        if (op->opnum == OP_ILLEGAL || op->status == nfserr_notsupp)
                return op_encode_hdr_size * sizeof(__be32);

        BUG_ON(OPDESC(op)->op_rsize_bop == NULL);
        return OPDESC(op)->op_rsize_bop(rqstp, op);
}

void warn_on_nonidempotent_op(struct nfsd4_op *op)
{
        if (OPDESC(op)->op_flags & OP_MODIFIES_SOMETHING) {
                pr_err("unable to encode reply to nonidempotent op %u (%s)\n",
                        op->opnum, nfsd4_op_name(op->opnum));
                WARN_ON_ONCE(1);
        }
}

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

static const struct svc_procedure nfsd_procedures4[2] = {
        [NFSPROC4_NULL] = {
                .pc_func = nfsd4_proc_null,
                .pc_decode = nfssvc_decode_voidarg,
                .pc_encode = nfssvc_encode_voidres,
                .pc_argsize = sizeof(struct nfsd_voidargs),
                .pc_argzero = sizeof(struct nfsd_voidargs),
                .pc_ressize = sizeof(struct nfsd_voidres),
                .pc_cachetype = RC_NOCACHE,
                .pc_xdrressize = 1,
                .pc_name = "NULL",
        },
        [NFSPROC4_COMPOUND] = {
                .pc_func = nfsd4_proc_compound,
                .pc_decode = nfs4svc_decode_compoundargs,
                .pc_encode = nfs4svc_encode_compoundres,
                .pc_argsize = sizeof(struct nfsd4_compoundargs),
                .pc_argzero = offsetof(struct nfsd4_compoundargs, iops),
                .pc_ressize = sizeof(struct nfsd4_compoundres),
                .pc_release = nfsd4_release_compoundargs,
                .pc_cachetype = RC_NOCACHE,
                .pc_xdrressize = NFSD_BUFSIZE/4,
                .pc_name = "COMPOUND",
        },
};

static DEFINE_PER_CPU_ALIGNED(unsigned long,
                              nfsd_count4[ARRAY_SIZE(nfsd_procedures4)]);
const struct svc_version nfsd_version4 = {
        .vs_vers                = 4,
        .vs_nproc               = ARRAY_SIZE(nfsd_procedures4),
        .vs_proc                = nfsd_procedures4,
        .vs_count               = nfsd_count4,
        .vs_dispatch            = nfsd_dispatch,
        .vs_xdrsize             = NFS4_SVC_XDRSIZE,
        .vs_rpcb_optnl          = true,
        .vs_need_cong_ctrl      = true,
};