stop shipping useless ksh93 builtins into /usr/bin

[unleashed.git] / kernel / fs / nfs / nfs4_vfsops.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 *      Copyright (c) 1983,1984,1985,1986,1987,1988,1989  AT&T.
 *      All Rights Reserved
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/cred.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/pathname.h>
#include <sys/sysmacros.h>
#include <sys/kmem.h>
#include <sys/mkdev.h>
#include <sys/mount.h>
#include <sys/statvfs.h>
#include <sys/errno.h>
#include <sys/debug.h>
#include <sys/cmn_err.h>
#include <sys/utsname.h>
#include <sys/bootconf.h>
#include <sys/modctl.h>
#include <sys/acl.h>
#include <sys/flock.h>
#include <sys/time.h>
#include <sys/disp.h>
#include <sys/policy.h>
#include <sys/socket.h>
#include <sys/netconfig.h>
#include <sys/dnlc.h>
#include <sys/list.h>
#include <sys/mntent.h>

#include <rpc/types.h>
#include <rpc/auth.h>
#include <rpc/rpcsec_gss.h>
#include <rpc/clnt.h>

#include <nfs/nfs.h>
#include <nfs/nfs_clnt.h>
#include <nfs/mount.h>
#include <nfs/nfs_acl.h>

#include <sys/fs_subr.h>

#include <nfs/nfs4.h>
#include <nfs/rnode4.h>
#include <nfs/nfs4_clnt.h>
#include <sys/fs/autofs.h>

#include <sys/sdt.h>


/*
 * Arguments passed to thread to free data structures from forced unmount.
 */

typedef struct {
        vfs_t   *fm_vfsp;
        int     fm_flag;
        cred_t  *fm_cr;
} freemountargs_t;

static void     async_free_mount(vfs_t *, int, cred_t *);
static void     nfs4_free_mount(vfs_t *, int, cred_t *);
static void     nfs4_free_mount_thread(freemountargs_t *);
static int nfs4_chkdup_servinfo4(servinfo4_t *, servinfo4_t *);

/*
 * From rpcsec module (common/rpcsec).
 */
extern int sec_clnt_loadinfo(struct sec_data *, struct sec_data **, model_t);
extern void sec_clnt_freeinfo(struct sec_data *);

/*
 * The order and contents of this structure must be kept in sync with that of
 * rfsreqcnt_v4_tmpl in nfs_stats.c
 */
static char *rfsnames_v4[] = {
        "null", "compound", "reserved", "access", "close", "commit", "create",
        "delegpurge", "delegreturn", "getattr", "getfh", "link", "lock",
        "lockt", "locku", "lookup", "lookupp", "nverify", "open", "openattr",
        "open_confirm", "open_downgrade", "putfh", "putpubfh", "putrootfh",
        "read", "readdir", "readlink", "remove", "rename", "renew",
        "restorefh", "savefh", "secinfo", "setattr", "setclientid",
        "setclientid_confirm", "verify", "write"
};

/*
 * nfs4_max_mount_retry is the number of times the client will redrive
 * a mount compound before giving up and returning failure.  The intent
 * is to redrive mount compounds which fail NFS4ERR_STALE so that
 * if a component of the server path being mounted goes stale, it can
 * "recover" by redriving the mount compund (LOOKUP ops).  This recovery
 * code is needed outside of the recovery framework because mount is a
 * special case.  The client doesn't create vnodes/rnodes for components
 * of the server path being mounted.  The recovery code recovers real
 * client objects, not STALE FHs which map to components of the server
 * path being mounted.
 *
 * We could just fail the mount on the first time, but that would
 * instantly trigger failover (from nfs4_mount), and the client should
 * try to re-lookup the STALE FH before doing failover.  The easiest
 * way to "re-lookup" is to simply redrive the mount compound.
 */
static int nfs4_max_mount_retry = 2;

/*
 * nfs4 vfs operations.
 */
int             nfs4_mount(vfs_t *, vnode_t *, struct mounta *, cred_t *);
static int      nfs4_unmount(vfs_t *, int, cred_t *);
static int      nfs4_root(vfs_t *, vnode_t **);
static int      nfs4_statvfs(vfs_t *, struct statvfs64 *);
static int      nfs4_sync(vfs_t *, short, cred_t *);
static int      nfs4_vget(vfs_t *, vnode_t **, fid_t *);
static int      nfs4_mountroot(vfs_t *, whymountroot_t);
static void     nfs4_freevfs(vfs_t *);

static int      nfs4rootvp(vnode_t **, vfs_t *, struct servinfo4 *,
                    int, cred_t *, zone_t *);


int nfs4_vfsinit(void);
void nfs4_vfsfini(void);
static void nfs4setclientid_init(void);
static void nfs4setclientid_fini(void);
static void nfs4setclientid_otw(mntinfo4_t *, servinfo4_t *,  cred_t *,
                struct nfs4_server *, nfs4_error_t *, int *);
static void     destroy_nfs4_server(nfs4_server_t *);
static void     remove_mi(nfs4_server_t *, mntinfo4_t *);

extern void nfs4_ephemeral_init(void);
extern void nfs4_ephemeral_fini(void);

/* referral related routines */
static servinfo4_t *copy_svp(servinfo4_t *);
static void free_knconf_contents(struct knetconfig *k);
static char *extract_referral_point(const char *, int);
static void setup_newsvpath(servinfo4_t *, int);
static void update_servinfo4(servinfo4_t *, fs_location4 *,
                struct nfs_fsl_info *, char *, int);

/*
 * Initialize the vfs structure
 */

static int nfs4fstyp;


/*
 * Debug variable to check for rdma based
 * transport startup and cleanup. Controlled
 * through /etc/system. Off by default.
 */
extern int rdma_debug;

const struct vfsops nfs4_vfsops = {
        .vfs_mount = nfs4_mount,
        .vfs_unmount = nfs4_unmount,
        .vfs_root = nfs4_root,
        .vfs_statvfs = nfs4_statvfs,
        .vfs_sync = nfs4_sync,
        .vfs_vget = nfs4_vget,
        .vfs_mountroot = nfs4_mountroot,
        .vfs_freevfs = nfs4_freevfs,
};

int
nfs4init(int fstyp, char *name)
{
        int error;

        error = vfs_setfsops(fstyp, &nfs4_vfsops);
        if (error != 0) {
                zcmn_err(GLOBAL_ZONEID, CE_WARN,
                    "nfs4init: bad fstyp");
                goto out;
        }

        nfs4fstyp = fstyp;
        (void) nfs4_vfsinit();
        (void) nfs4_init_dot_entries();

out:
        if (error)
                (void) vfs_freevfsops_by_type(fstyp);

        return (error);
}

void
nfs4fini(void)
{
        (void) nfs4_destroy_dot_entries();
        nfs4_vfsfini();
}

/*
 * Create a new sec_data structure to store AUTH_DH related data:
 * netname, syncaddr, knetconfig. There is no AUTH_F_RPCTIMESYNC
 * flag set for NFS V4 since we are avoiding to contact the rpcbind
 * daemon and is using the IP time service (IPPORT_TIMESERVER).
 *
 * sec_data can be freed by sec_clnt_freeinfo().
 */
static struct sec_data *
create_authdh_data(char *netname, int nlen, struct netbuf *syncaddr,
    struct knetconfig *knconf)
{
        struct sec_data *secdata;
        dh_k4_clntdata_t *data;
        char *pf, *p;

        if (syncaddr == NULL || syncaddr->buf == NULL || nlen == 0)
                return (NULL);

        secdata = kmem_alloc(sizeof (*secdata), KM_SLEEP);
        secdata->flags = 0;

        data = kmem_alloc(sizeof (*data), KM_SLEEP);

        data->syncaddr.maxlen = syncaddr->maxlen;
        data->syncaddr.len = syncaddr->len;
        data->syncaddr.buf = kmem_alloc(syncaddr->len, KM_SLEEP);
        bcopy(syncaddr->buf, data->syncaddr.buf, syncaddr->len);

        /*
         * duplicate the knconf information for the
         * new opaque data.
         */
        data->knconf = kmem_alloc(sizeof (*knconf), KM_SLEEP);
        *data->knconf = *knconf;
        pf = kmem_alloc(KNC_STRSIZE, KM_SLEEP);
        p = kmem_alloc(KNC_STRSIZE, KM_SLEEP);
        bcopy(knconf->knc_protofmly, pf, KNC_STRSIZE);
        bcopy(knconf->knc_proto, p, KNC_STRSIZE);
        data->knconf->knc_protofmly = pf;
        data->knconf->knc_proto = p;

        /* move server netname to the sec_data structure */
        data->netname = kmem_alloc(nlen, KM_SLEEP);
        bcopy(netname, data->netname, nlen);
        data->netnamelen = (int)nlen;

        secdata->secmod = AUTH_DH;
        secdata->rpcflavor = AUTH_DH;
        secdata->data = (caddr_t)data;

        return (secdata);
}

/*
 * Returns (deep) copy of sec_data_t. Allocates all memory required; caller
 * is responsible for freeing.
 */
sec_data_t *
copy_sec_data(sec_data_t *fsecdata)
{
        sec_data_t *tsecdata;

        if (fsecdata == NULL)
                return (NULL);

        if (fsecdata->rpcflavor == AUTH_DH) {
                dh_k4_clntdata_t *fdata = (dh_k4_clntdata_t *)fsecdata->data;

                if (fdata == NULL)
                        return (NULL);

                tsecdata = (sec_data_t *)create_authdh_data(fdata->netname,
                    fdata->netnamelen, &fdata->syncaddr, fdata->knconf);

                return (tsecdata);
        }

        tsecdata = kmem_zalloc(sizeof (sec_data_t), KM_SLEEP);

        tsecdata->secmod = fsecdata->secmod;
        tsecdata->rpcflavor = fsecdata->rpcflavor;
        tsecdata->flags = fsecdata->flags;
        tsecdata->uid = fsecdata->uid;

        if (fsecdata->rpcflavor == RPCSEC_GSS) {
                gss_clntdata_t *gcd = (gss_clntdata_t *)fsecdata->data;

                tsecdata->data = (caddr_t)copy_sec_data_gss(gcd);
        } else {
                tsecdata->data = NULL;
        }

        return (tsecdata);
}

gss_clntdata_t *
copy_sec_data_gss(gss_clntdata_t *fdata)
{
        gss_clntdata_t *tdata;

        if (fdata == NULL)
                return (NULL);

        tdata = kmem_zalloc(sizeof (gss_clntdata_t), KM_SLEEP);

        tdata->mechanism.length = fdata->mechanism.length;
        tdata->mechanism.elements = kmem_zalloc(fdata->mechanism.length,
            KM_SLEEP);
        bcopy(fdata->mechanism.elements, tdata->mechanism.elements,
            fdata->mechanism.length);

        tdata->service = fdata->service;

        (void) strcpy(tdata->uname, fdata->uname);
        (void) strcpy(tdata->inst, fdata->inst);
        (void) strcpy(tdata->realm, fdata->realm);

        tdata->qop = fdata->qop;

        return (tdata);
}

static int
nfs4_chkdup_servinfo4(servinfo4_t *svp_head, servinfo4_t *svp)
{
        servinfo4_t *si;

        /*
         * Iterate over the servinfo4 list to make sure
         * we do not have a duplicate. Skip any servinfo4
         * that has been marked "NOT IN USE"
         */
        for (si = svp_head; si; si = si->sv_next) {
                (void) nfs_rw_enter_sig(&si->sv_lock, RW_READER, 0);
                if (si->sv_flags & SV4_NOTINUSE) {
                        nfs_rw_exit(&si->sv_lock);
                        continue;
                }
                nfs_rw_exit(&si->sv_lock);
                if (si == svp)
                        continue;
                if (si->sv_addr.len == svp->sv_addr.len &&
                    strcmp(si->sv_knconf->knc_protofmly,
                    svp->sv_knconf->knc_protofmly) == 0 &&
                    bcmp(si->sv_addr.buf, svp->sv_addr.buf,
                    si->sv_addr.len) == 0) {
                        /* it's a duplicate */
                        return (1);
                }
        }
        /* it's not a duplicate */
        return (0);
}

void
nfs4_free_args(struct nfs_args *nargs)
{
        if (nargs->knconf) {
                if (nargs->knconf->knc_protofmly)
                        kmem_free(nargs->knconf->knc_protofmly,
                            KNC_STRSIZE);
                if (nargs->knconf->knc_proto)
                        kmem_free(nargs->knconf->knc_proto, KNC_STRSIZE);
                kmem_free(nargs->knconf, sizeof (*nargs->knconf));
                nargs->knconf = NULL;
        }

        if (nargs->fh) {
                kmem_free(nargs->fh, strlen(nargs->fh) + 1);
                nargs->fh = NULL;
        }

        if (nargs->hostname) {
                kmem_free(nargs->hostname, strlen(nargs->hostname) + 1);
                nargs->hostname = NULL;
        }

        if (nargs->addr) {
                if (nargs->addr->buf) {
                        ASSERT(nargs->addr->len);
                        kmem_free(nargs->addr->buf, nargs->addr->len);
                }
                kmem_free(nargs->addr, sizeof (struct netbuf));
                nargs->addr = NULL;
        }

        if (nargs->syncaddr) {
                ASSERT(nargs->syncaddr->len);
                if (nargs->syncaddr->buf) {
                        ASSERT(nargs->syncaddr->len);
                        kmem_free(nargs->syncaddr->buf, nargs->syncaddr->len);
                }
                kmem_free(nargs->syncaddr, sizeof (struct netbuf));
                nargs->syncaddr = NULL;
        }

        if (nargs->netname) {
                kmem_free(nargs->netname, strlen(nargs->netname) + 1);
                nargs->netname = NULL;
        }

        if (nargs->nfs_ext_u.nfs_extA.secdata) {
                sec_clnt_freeinfo(
                    nargs->nfs_ext_u.nfs_extA.secdata);
                nargs->nfs_ext_u.nfs_extA.secdata = NULL;
        }
}


int
nfs4_copyin(char *data, int datalen, struct nfs_args *nargs)
{

        int error;
        size_t hlen;                    /* length of hostname */
        size_t nlen;                    /* length of netname */
        char netname[MAXNETNAMELEN+1];  /* server's netname */
        struct netbuf addr;             /* server's address */
        struct netbuf syncaddr;         /* AUTH_DES time sync addr */
        struct knetconfig *knconf;              /* transport structure */
        struct sec_data *secdata = NULL;        /* security data */
        STRUCT_DECL(nfs_args, args);            /* nfs mount arguments */
        STRUCT_DECL(knetconfig, knconf_tmp);
        STRUCT_DECL(netbuf, addr_tmp);
        int flags;
        char *p, *pf;
        struct pathname pn;
        char *userbufptr;


        bzero(nargs, sizeof (*nargs));

        STRUCT_INIT(args, get_udatamodel());
        bzero(STRUCT_BUF(args), SIZEOF_STRUCT(nfs_args, DATAMODEL_NATIVE));
        if (copyin(data, STRUCT_BUF(args), MIN(datalen,
            STRUCT_SIZE(args))))
                return (EFAULT);

        nargs->wsize = STRUCT_FGET(args, wsize);
        nargs->rsize = STRUCT_FGET(args, rsize);
        nargs->timeo = STRUCT_FGET(args, timeo);
        nargs->retrans = STRUCT_FGET(args, retrans);
        nargs->acregmin = STRUCT_FGET(args, acregmin);
        nargs->acregmax = STRUCT_FGET(args, acregmax);
        nargs->acdirmin = STRUCT_FGET(args, acdirmin);
        nargs->acdirmax = STRUCT_FGET(args, acdirmax);

        flags = STRUCT_FGET(args, flags);
        nargs->flags = flags;

        addr.buf = NULL;
        syncaddr.buf = NULL;


        /*
         * Allocate space for a knetconfig structure and
         * its strings and copy in from user-land.
         */
        knconf = kmem_zalloc(sizeof (*knconf), KM_SLEEP);
        STRUCT_INIT(knconf_tmp, get_udatamodel());
        if (copyin(STRUCT_FGETP(args, knconf), STRUCT_BUF(knconf_tmp),
            STRUCT_SIZE(knconf_tmp))) {
                kmem_free(knconf, sizeof (*knconf));
                return (EFAULT);
        }

        knconf->knc_semantics = STRUCT_FGET(knconf_tmp, knc_semantics);
        knconf->knc_protofmly = STRUCT_FGETP(knconf_tmp, knc_protofmly);
        knconf->knc_proto = STRUCT_FGETP(knconf_tmp, knc_proto);
        if (get_udatamodel() != DATAMODEL_LP64) {
                knconf->knc_rdev = expldev(STRUCT_FGET(knconf_tmp, knc_rdev));
        } else {
                knconf->knc_rdev = STRUCT_FGET(knconf_tmp, knc_rdev);
        }

        pf = kmem_alloc(KNC_STRSIZE, KM_SLEEP);
        p = kmem_alloc(KNC_STRSIZE, KM_SLEEP);
        error = copyinstr(knconf->knc_protofmly, pf, KNC_STRSIZE, NULL);
        if (error) {
                kmem_free(pf, KNC_STRSIZE);
                kmem_free(p, KNC_STRSIZE);
                kmem_free(knconf, sizeof (*knconf));
                return (error);
        }

        error = copyinstr(knconf->knc_proto, p, KNC_STRSIZE, NULL);
        if (error) {
                kmem_free(pf, KNC_STRSIZE);
                kmem_free(p, KNC_STRSIZE);
                kmem_free(knconf, sizeof (*knconf));
                return (error);
        }


        knconf->knc_protofmly = pf;
        knconf->knc_proto = p;

        nargs->knconf = knconf;

        /*
         * Get server address
         */
        STRUCT_INIT(addr_tmp, get_udatamodel());
        if (copyin(STRUCT_FGETP(args, addr), STRUCT_BUF(addr_tmp),
            STRUCT_SIZE(addr_tmp))) {
                error = EFAULT;
                goto errout;
        }

        nargs->addr = kmem_zalloc(sizeof (struct netbuf), KM_SLEEP);
        userbufptr = STRUCT_FGETP(addr_tmp, buf);
        addr.len = STRUCT_FGET(addr_tmp, len);
        addr.buf = kmem_alloc(addr.len, KM_SLEEP);
        addr.maxlen = addr.len;
        if (copyin(userbufptr, addr.buf, addr.len)) {
                kmem_free(addr.buf, addr.len);
                error = EFAULT;
                goto errout;
        }
        bcopy(&addr, nargs->addr, sizeof (struct netbuf));

        /*
         * Get the root fhandle
         */
        error = pn_get(STRUCT_FGETP(args, fh), UIO_USERSPACE, &pn);
        if (error)
                goto errout;

        /* Volatile fh: keep server paths, so use actual-size strings */
        nargs->fh = kmem_alloc(pn.pn_pathlen + 1, KM_SLEEP);
        bcopy(pn.pn_path, nargs->fh, pn.pn_pathlen);
        nargs->fh[pn.pn_pathlen] = '\0';
        pn_free(&pn);


        /*
         * Get server's hostname
         */
        if (flags & NFSMNT_HOSTNAME) {
                error = copyinstr(STRUCT_FGETP(args, hostname),
                    netname, sizeof (netname), &hlen);
                if (error)
                        goto errout;
                nargs->hostname = kmem_zalloc(hlen, KM_SLEEP);
                (void) strcpy(nargs->hostname, netname);

        } else {
                nargs->hostname = NULL;
        }


        /*
         * If there are syncaddr and netname data, load them in. This is
         * to support data needed for NFSV4 when AUTH_DH is the negotiated
         * flavor via SECINFO. (instead of using MOUNT protocol in V3).
         */
        netname[0] = '\0';
        if (flags & NFSMNT_SECURE) {

                /* get syncaddr */
                STRUCT_INIT(addr_tmp, get_udatamodel());
                if (copyin(STRUCT_FGETP(args, syncaddr), STRUCT_BUF(addr_tmp),
                    STRUCT_SIZE(addr_tmp))) {
                        error = EINVAL;
                        goto errout;
                }
                userbufptr = STRUCT_FGETP(addr_tmp, buf);
                syncaddr.len = STRUCT_FGET(addr_tmp, len);
                syncaddr.buf = kmem_alloc(syncaddr.len, KM_SLEEP);
                syncaddr.maxlen = syncaddr.len;
                if (copyin(userbufptr, syncaddr.buf, syncaddr.len)) {
                        kmem_free(syncaddr.buf, syncaddr.len);
                        error = EFAULT;
                        goto errout;
                }

                nargs->syncaddr = kmem_alloc(sizeof (struct netbuf), KM_SLEEP);
                bcopy(&syncaddr, nargs->syncaddr, sizeof (struct netbuf));

                /* get server's netname */
                if (copyinstr(STRUCT_FGETP(args, netname), netname,
                    sizeof (netname), &nlen)) {
                        error = EFAULT;
                        goto errout;
                }

                netname[nlen] = '\0';
                nargs->netname = kmem_zalloc(nlen, KM_SLEEP);
                (void) strcpy(nargs->netname, netname);
        }

        /*
         * Get the extention data which has the security data structure.
         * This includes data for AUTH_SYS as well.
         */
        if (flags & NFSMNT_NEWARGS) {
                nargs->nfs_args_ext = STRUCT_FGET(args, nfs_args_ext);
                if (nargs->nfs_args_ext == NFS_ARGS_EXTA ||
                    nargs->nfs_args_ext == NFS_ARGS_EXTB) {
                        /*
                         * Indicating the application is using the new
                         * sec_data structure to pass in the security
                         * data.
                         */
                        if (STRUCT_FGETP(args,
                            nfs_ext_u.nfs_extA.secdata) != NULL) {
                                error = sec_clnt_loadinfo(
                                    (struct sec_data *)STRUCT_FGETP(args,
                                    nfs_ext_u.nfs_extA.secdata),
                                    &secdata, get_udatamodel());
                        }
                        nargs->nfs_ext_u.nfs_extA.secdata = secdata;
                }
        }

        if (error)
                goto errout;

        /*
         * Failover support:
         *
         * We may have a linked list of nfs_args structures,
         * which means the user is looking for failover.  If
         * the mount is either not "read-only" or "soft",
         * we want to bail out with EINVAL.
         */
        if (nargs->nfs_args_ext == NFS_ARGS_EXTB)
                nargs->nfs_ext_u.nfs_extB.next =
                    STRUCT_FGETP(args, nfs_ext_u.nfs_extB.next);

errout:
        if (error)
                nfs4_free_args(nargs);

        return (error);
}


/*
 * nfs mount vfsop
 * Set up mount info record and attach it to vfs struct.
 */
int
nfs4_mount(vfs_t *vfsp, vnode_t *mvp, struct mounta *uap, cred_t *cr)
{
        char *data = uap->dataptr;
        int error;
        vnode_t *rtvp;                  /* the server's root */
        mntinfo4_t *mi;                 /* mount info, pointed at by vfs */
        struct knetconfig *rdma_knconf; /* rdma transport structure */
        rnode4_t *rp;
        struct servinfo4 *svp;          /* nfs server info */
        struct servinfo4 *svp_tail = NULL; /* previous nfs server info */
        struct servinfo4 *svp_head;     /* first nfs server info */
        struct servinfo4 *svp_2ndlast;  /* 2nd last in server info list */
        struct sec_data *secdata;       /* security data */
        struct nfs_args *args = NULL;
        int flags, addr_type, removed;
        zone_t *zone = nfs_zone();
        nfs4_error_t n4e;
        zone_t *mntzone = NULL;

        if (secpolicy_fs_mount(cr, mvp, vfsp) != 0)
                return (EPERM);
        if (mvp->v_type != VDIR)
                return (ENOTDIR);

        /*
         * get arguments
         *
         * nfs_args is now versioned and is extensible, so
         * uap->datalen might be different from sizeof (args)
         * in a compatible situation.
         */
more:
        if (!(uap->flags & MS_SYSSPACE)) {
                if (args == NULL)
                        args = kmem_zalloc(sizeof (struct nfs_args), KM_SLEEP);
                else
                        nfs4_free_args(args);
                error = nfs4_copyin(data, uap->datalen, args);
                if (error) {
                        if (args) {
                                kmem_free(args, sizeof (*args));
                        }
                        return (error);
                }
        } else {
                args = (struct nfs_args *)data;
        }

        flags = args->flags;

        /*
         * If the request changes the locking type, disallow the remount,
         * because it's questionable whether we can transfer the
         * locking state correctly.
         */
        if (uap->flags & MS_REMOUNT) {
                if (!(uap->flags & MS_SYSSPACE)) {
                        nfs4_free_args(args);
                        kmem_free(args, sizeof (*args));
                }
                if ((mi = VFTOMI4(vfsp)) != NULL) {
                        uint_t new_mi_llock;
                        uint_t old_mi_llock;
                        new_mi_llock = (flags & NFSMNT_LLOCK) ? 1 : 0;
                        old_mi_llock = (mi->mi_flags & MI4_LLOCK) ? 1 : 0;
                        if (old_mi_llock != new_mi_llock)
                                return (EBUSY);
                }
                return (0);
        }

        /*
         * For ephemeral mount trigger stub vnodes, we have two problems
         * to solve: racing threads will likely fail the v_count check, and
         * we want only one to proceed with the mount.
         *
         * For stubs, if the mount has already occurred (via a racing thread),
         * just return success. If not, skip the v_count check and proceed.
         * Note that we are already serialised at this point.
         */
        mutex_enter(&mvp->v_lock);
        if (vn_matchops(mvp, &nfs4_trigger_vnodeops)) {
                /* mntpt is a v4 stub vnode */
                ASSERT(RP_ISSTUB(VTOR4(mvp)));
                ASSERT(!(uap->flags & MS_OVERLAY));
                ASSERT(!(mvp->v_flag & VROOT));
                if (vn_mountedvfs(mvp) != NULL) {
                        /* ephemeral mount has already occurred */
                        ASSERT(uap->flags & MS_SYSSPACE);
                        mutex_exit(&mvp->v_lock);
                        return (0);
                }
        } else {
                /* mntpt is a non-v4 or v4 non-stub vnode */
                if (!(uap->flags & MS_OVERLAY) &&
                    (mvp->v_count != 1 || (mvp->v_flag & VROOT))) {
                        mutex_exit(&mvp->v_lock);
                        if (!(uap->flags & MS_SYSSPACE)) {
                                nfs4_free_args(args);
                                kmem_free(args, sizeof (*args));
                        }
                        return (EBUSY);
                }
        }
        mutex_exit(&mvp->v_lock);

        /* make sure things are zeroed for errout: */
        rtvp = NULL;
        mi = NULL;
        secdata = NULL;

        /*
         * A valid knetconfig structure is required.
         */
        if (!(flags & NFSMNT_KNCONF) ||
            args->knconf == NULL || args->knconf->knc_protofmly == NULL ||
            args->knconf->knc_proto == NULL ||
            (strcmp(args->knconf->knc_proto, NC_UDP) == 0)) {
                if (!(uap->flags & MS_SYSSPACE)) {
                        nfs4_free_args(args);
                        kmem_free(args, sizeof (*args));
                }
                return (EINVAL);
        }

        if ((strlen(args->knconf->knc_protofmly) >= KNC_STRSIZE) ||
            (strlen(args->knconf->knc_proto) >= KNC_STRSIZE)) {
                if (!(uap->flags & MS_SYSSPACE)) {
                        nfs4_free_args(args);
                        kmem_free(args, sizeof (*args));
                }
                return (EINVAL);
        }

        /*
         * Allocate a servinfo4 struct.
         */
        svp = kmem_zalloc(sizeof (*svp), KM_SLEEP);
        nfs_rw_init(&svp->sv_lock, NULL, RW_DEFAULT, NULL);
        if (svp_tail) {
                svp_2ndlast = svp_tail;
                svp_tail->sv_next = svp;
        } else {
                svp_head = svp;
                svp_2ndlast = svp;
        }

        svp_tail = svp;
        svp->sv_knconf = args->knconf;
        args->knconf = NULL;

        /*
         * Get server address
         */
        if (args->addr == NULL || args->addr->buf == NULL) {
                error = EINVAL;
                goto errout;
        }

        svp->sv_addr.maxlen = args->addr->maxlen;
        svp->sv_addr.len = args->addr->len;
        svp->sv_addr.buf = args->addr->buf;
        args->addr->buf = NULL;

        /*
         * Get the root fhandle
         */
        if (args->fh == NULL || (strlen(args->fh) >= MAXPATHLEN)) {
                error = EINVAL;
                goto errout;
        }

        svp->sv_path = args->fh;
        svp->sv_pathlen = strlen(args->fh) + 1;
        args->fh = NULL;

        /*
         * Get server's hostname
         */
        if (flags & NFSMNT_HOSTNAME) {
                if (args->hostname == NULL || (strlen(args->hostname) >
                    MAXNETNAMELEN)) {
                        error = EINVAL;
                        goto errout;
                }
                svp->sv_hostnamelen = strlen(args->hostname) + 1;
                svp->sv_hostname = args->hostname;
                args->hostname = NULL;
        } else {
                char *p = "unknown-host";
                svp->sv_hostnamelen = strlen(p) + 1;
                svp->sv_hostname = kmem_zalloc(svp->sv_hostnamelen, KM_SLEEP);
                (void) strcpy(svp->sv_hostname, p);
        }

        /*
         * RDMA MOUNT SUPPORT FOR NFS v4.
         * Establish, is it possible to use RDMA, if so overload the
         * knconf with rdma specific knconf and free the orignal knconf.
         */
        if ((flags & NFSMNT_TRYRDMA) || (flags & NFSMNT_DORDMA)) {
                /*
                 * Determine the addr type for RDMA, IPv4 or v6.
                 */
                if (strcmp(svp->sv_knconf->knc_protofmly, NC_INET) == 0)
                        addr_type = AF_INET;
                else if (strcmp(svp->sv_knconf->knc_protofmly, NC_INET6) == 0)
                        addr_type = AF_INET6;

                if (rdma_reachable(addr_type, &svp->sv_addr,
                    &rdma_knconf) == 0) {
                        /*
                         * If successful, hijack the orignal knconf and
                         * replace with the new one, depending on the flags.
                         */
                        svp->sv_origknconf = svp->sv_knconf;
                        svp->sv_knconf = rdma_knconf;
                } else {
                        if (flags & NFSMNT_TRYRDMA) {
#ifdef  DEBUG
                                if (rdma_debug)
                                        zcmn_err(getzoneid(), CE_WARN,
                                            "no RDMA onboard, revert\n");
#endif
                        }

                        if (flags & NFSMNT_DORDMA) {
                                /*
                                 * If proto=rdma is specified and no RDMA
                                 * path to this server is avialable then
                                 * ditch this server.
                                 * This is not included in the mountable
                                 * server list or the replica list.
                                 * Check if more servers are specified;
                                 * Failover case, otherwise bail out of mount.
                                 */
                                if (args->nfs_args_ext == NFS_ARGS_EXTB &&
                                    args->nfs_ext_u.nfs_extB.next != NULL) {
                                        data = (char *)
                                            args->nfs_ext_u.nfs_extB.next;
                                        if (uap->flags & MS_RDONLY &&
                                            !(flags & NFSMNT_SOFT)) {
                                                if (svp_head->sv_next == NULL) {
                                                        svp_tail = NULL;
                                                        svp_2ndlast = NULL;
                                                        sv4_free(svp_head);
                                                        goto more;
                                                } else {
                                                        svp_tail = svp_2ndlast;
                                                        svp_2ndlast->sv_next =
                                                            NULL;
                                                        sv4_free(svp);
                                                        goto more;
                                                }
                                        }
                                } else {
                                        /*
                                         * This is the last server specified
                                         * in the nfs_args list passed down
                                         * and its not rdma capable.
                                         */
                                        if (svp_head->sv_next == NULL) {
                                                /*
                                                 * Is this the only one
                                                 */
                                                error = EINVAL;
#ifdef  DEBUG
                                                if (rdma_debug)
                                                        zcmn_err(getzoneid(),
                                                            CE_WARN,
                                                            "No RDMA srv");
#endif
                                                goto errout;
                                        } else {
                                                /*
                                                 * There is list, since some
                                                 * servers specified before
                                                 * this passed all requirements
                                                 */
                                                svp_tail = svp_2ndlast;
                                                svp_2ndlast->sv_next = NULL;
                                                sv4_free(svp);
                                                goto proceed;
                                        }
                                }
                        }
                }
        }

        /*
         * If there are syncaddr and netname data, load them in. This is
         * to support data needed for NFSV4 when AUTH_DH is the negotiated
         * flavor via SECINFO. (instead of using MOUNT protocol in V3).
         */
        if (args->flags & NFSMNT_SECURE) {
                svp->sv_dhsec = create_authdh_data(args->netname,
                    strlen(args->netname),
                    args->syncaddr, svp->sv_knconf);
        }

        /*
         * Get the extention data which has the security data structure.
         * This includes data for AUTH_SYS as well.
         */
        if (flags & NFSMNT_NEWARGS) {
                switch (args->nfs_args_ext) {
                case NFS_ARGS_EXTA:
                case NFS_ARGS_EXTB:
                        /*
                         * Indicating the application is using the new
                         * sec_data structure to pass in the security
                         * data.
                         */
                        secdata = args->nfs_ext_u.nfs_extA.secdata;
                        if (secdata == NULL) {
                                error = EINVAL;
                        } else if (uap->flags & MS_SYSSPACE) {
                                /*
                                 * Need to validate the flavor here if
                                 * sysspace, userspace was already
                                 * validate from the nfs_copyin function.
                                 */
                                switch (secdata->rpcflavor) {
                                case AUTH_NONE:
                                case AUTH_UNIX:
                                case AUTH_LOOPBACK:
                                case AUTH_DES:
                                case RPCSEC_GSS:
                                        break;
                                default:
                                        error = EINVAL;
                                        goto errout;
                                }
                        }
                        args->nfs_ext_u.nfs_extA.secdata = NULL;
                        break;

                default:
                        error = EINVAL;
                        break;
                }

        } else if (flags & NFSMNT_SECURE) {
                /*
                 * NFSMNT_SECURE is deprecated but we keep it
                 * to support the rogue user-generated application
                 * that may use this undocumented interface to do
                 * AUTH_DH security, e.g. our own rexd.
                 *
                 * Also note that NFSMNT_SECURE is used for passing
                 * AUTH_DH info to be used in negotiation.
                 */
                secdata = create_authdh_data(args->netname,
                    strlen(args->netname), args->syncaddr, svp->sv_knconf);

        } else {
                secdata = kmem_alloc(sizeof (*secdata), KM_SLEEP);
                secdata->secmod = secdata->rpcflavor = AUTH_SYS;
                secdata->data = NULL;
        }

        svp->sv_secdata = secdata;

        /*
         * User does not explictly specify a flavor, and a user
         * defined default flavor is passed down.
         */
        if (flags & NFSMNT_SECDEFAULT) {
                (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
                svp->sv_flags |= SV4_TRYSECDEFAULT;
                nfs_rw_exit(&svp->sv_lock);
        }

        /*
         * Failover support:
         *
         * We may have a linked list of nfs_args structures,
         * which means the user is looking for failover.  If
         * the mount is either not "read-only" or "soft",
         * we want to bail out with EINVAL.
         */
        if (args->nfs_args_ext == NFS_ARGS_EXTB &&
            args->nfs_ext_u.nfs_extB.next != NULL) {
                if (uap->flags & MS_RDONLY && !(flags & NFSMNT_SOFT)) {
                        data = (char *)args->nfs_ext_u.nfs_extB.next;
                        goto more;
                }
                error = EINVAL;
                goto errout;
        }

        /*
         * Determine the zone we're being mounted into.
         */
        zone_hold(mntzone = zone);              /* start with this assumption */
        if (getzoneid() == GLOBAL_ZONEID) {
                zone_rele(mntzone);
                mntzone = zone_find_by_path(refstr_value(vfsp->vfs_mntpt));
                ASSERT(mntzone != NULL);
                if (mntzone != zone) {
                        error = EBUSY;
                        goto errout;
                }
        }

        /*
         * Stop the mount from going any further if the zone is going away.
         */
        if (zone_status_get(mntzone) >= ZONE_IS_SHUTTING_DOWN) {
                error = EBUSY;
                goto errout;
        }

        /*
         * Get root vnode.
         */
proceed:
        error = nfs4rootvp(&rtvp, vfsp, svp_head, flags, cr, mntzone);
        if (error) {
                /* if nfs4rootvp failed, it will free svp_head */
                svp_head = NULL;
                goto errout;
        }

        mi = VTOMI4(rtvp);

        /*
         * Send client id to the server, if necessary
         */
        nfs4_error_zinit(&n4e);
        nfs4setclientid(mi, cr, FALSE, &n4e);

        error = n4e.error;

        if (error)
                goto errout;

        /*
         * Set option fields in the mount info record
         */

        if (svp_head->sv_next) {
                mutex_enter(&mi->mi_lock);
                mi->mi_flags |= MI4_LLOCK;
                mutex_exit(&mi->mi_lock);
        }
        error = nfs4_setopts(rtvp, DATAMODEL_NATIVE, args);
        if (error)
                goto errout;

        /*
         * Time to tie in the mirror mount info at last!
         */
        if (flags & NFSMNT_EPHEMERAL)
                error = nfs4_record_ephemeral_mount(mi, mvp);

errout:
        if (error) {
                if (rtvp != NULL) {
                        rp = VTOR4(rtvp);
                        if (rp->r_flags & R4HASHED)
                                rp4_rmhash(rp);
                }
                if (mi != NULL) {
                        nfs4_async_stop(vfsp);
                        nfs4_async_manager_stop(vfsp);
                        nfs4_remove_mi_from_server(mi, NULL);
                        if (rtvp != NULL)
                                VN_RELE(rtvp);
                        if (mntzone != NULL)
                                zone_rele(mntzone);
                        /* need to remove it from the zone */
                        removed = nfs4_mi_zonelist_remove(mi);
                        if (removed)
                                zone_rele_ref(&mi->mi_zone_ref,
                                    ZONE_REF_NFSV4);
                        MI4_RELE(mi);
                        if (!(uap->flags & MS_SYSSPACE) && args) {
                                nfs4_free_args(args);
                                kmem_free(args, sizeof (*args));
                        }
                        return (error);
                }
                if (svp_head)
                        sv4_free(svp_head);
        }

        if (!(uap->flags & MS_SYSSPACE) && args) {
                nfs4_free_args(args);
                kmem_free(args, sizeof (*args));
        }
        if (rtvp != NULL)
                VN_RELE(rtvp);

        if (mntzone != NULL)
                zone_rele(mntzone);

        return (error);
}

#ifdef  DEBUG
#define VERS_MSG        "NFS4 server "
#else
#define VERS_MSG        "NFS server "
#endif

#define READ_MSG        \
        VERS_MSG "%s returned 0 for read transfer size"
#define WRITE_MSG       \
        VERS_MSG "%s returned 0 for write transfer size"
#define SIZE_MSG        \
        VERS_MSG "%s returned 0 for maximum file size"

/*
 * Get the symbolic link text from the server for a given filehandle
 * of that symlink.
 *
 *      (get symlink text) PUTFH READLINK
 */
static int
getlinktext_otw(mntinfo4_t *mi, nfs_fh4 *fh, char **linktextp, cred_t *cr,
    int flags)
{
        COMPOUND4args_clnt args;
        COMPOUND4res_clnt res;
        int doqueue;
        nfs_argop4 argop[2];
        nfs_resop4 *resop;
        READLINK4res *lr_res;
        uint_t len;
        bool_t needrecov = FALSE;
        nfs4_recov_state_t recov_state;
        nfs4_sharedfh_t *sfh;
        nfs4_error_t e;
        int num_retry = nfs4_max_mount_retry;
        int recovery = !(flags & NFS4_GETFH_NEEDSOP);

        sfh = sfh4_get(fh, mi);
        recov_state.rs_flags = 0;
        recov_state.rs_num_retry_despite_err = 0;

recov_retry:
        nfs4_error_zinit(&e);

        args.array_len = 2;
        args.array = argop;
        args.ctag = TAG_GET_SYMLINK;

        if (! recovery) {
                e.error = nfs4_start_op(mi, NULL, NULL, &recov_state);
                if (e.error) {
                        sfh4_rele(&sfh);
                        return (e.error);
                }
        }

        /* 0. putfh symlink fh */
        argop[0].argop = OP_CPUTFH;
        argop[0].nfs_argop4_u.opcputfh.sfh = sfh;

        /* 1. readlink */
        argop[1].argop = OP_READLINK;

        doqueue = 1;

        rfs4call(mi, &args, &res, cr, &doqueue, 0, &e);

        needrecov = nfs4_needs_recovery(&e, FALSE, mi->mi_vfsp);

        if (needrecov && !recovery && num_retry-- > 0) {

                NFS4_DEBUG(nfs4_client_recov_debug, (CE_NOTE,
                    "getlinktext_otw: initiating recovery\n"));

                if (nfs4_start_recovery(&e, mi, NULL, NULL, NULL, NULL,
                    OP_READLINK, NULL, NULL, NULL) == FALSE) {
                        nfs4_end_op(mi, NULL, NULL, &recov_state, needrecov);
                        if (!e.error)
                                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
                        goto recov_retry;
                }
        }

        /*
         * If non-NFS4 pcol error and/or we weren't able to recover.
         */
        if (e.error != 0) {
                if (! recovery)
                        nfs4_end_op(mi, NULL, NULL, &recov_state, needrecov);
                sfh4_rele(&sfh);
                return (e.error);
        }

        if (res.status) {
                e.error = geterrno4(res.status);
                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
                if (! recovery)
                        nfs4_end_op(mi, NULL, NULL, &recov_state, needrecov);
                sfh4_rele(&sfh);
                return (e.error);
        }

        /* res.status == NFS4_OK */
        ASSERT(res.status == NFS4_OK);

        resop = &res.array[1];  /* readlink res */
        lr_res = &resop->nfs_resop4_u.opreadlink;

        /* treat symlink name as data */
        *linktextp = utf8_to_str((utf8string *)&lr_res->link, &len, NULL);

        if (! recovery)
                nfs4_end_op(mi, NULL, NULL, &recov_state, needrecov);
        sfh4_rele(&sfh);
        xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
        return (0);
}

/*
 * Skip over consecutive slashes and "/./" in a pathname.
 */
void
pathname_skipslashdot(struct pathname *pnp)
{
        char *c1, *c2;

        while (pnp->pn_pathlen > 0 && *pnp->pn_path == '/') {

                c1 = pnp->pn_path + 1;
                c2 = pnp->pn_path + 2;

                if (*c1 == '.' && (*c2 == '/' || *c2 == '\0')) {
                        pnp->pn_path = pnp->pn_path + 2; /* skip "/." */
                        pnp->pn_pathlen = pnp->pn_pathlen - 2;
                } else {
                        pnp->pn_path++;
                        pnp->pn_pathlen--;
                }
        }
}

/*
 * Resolve a symbolic link path. The symlink is in the nth component of
 * svp->sv_path and has an nfs4 file handle "fh".
 * Upon return, the sv_path will point to the new path that has the nth
 * component resolved to its symlink text.
 */
int
resolve_sympath(mntinfo4_t *mi, servinfo4_t *svp, int nth, nfs_fh4 *fh,
    cred_t *cr, int flags)
{
        char *oldpath;
        char *symlink, *newpath;
        struct pathname oldpn, newpn;
        char component[MAXNAMELEN];
        int i, addlen, error = 0;
        int oldpathlen;

        /* Get the symbolic link text over the wire. */
        error = getlinktext_otw(mi, fh, &symlink, cr, flags);

        if (error || symlink == NULL || strlen(symlink) == 0)
                return (error);

        /*
         * Compose the new pathname.
         * Note:
         *    - only the nth component is resolved for the pathname.
         *    - pathname.pn_pathlen does not count the ending null byte.
         */
        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
        oldpath = svp->sv_path;
        oldpathlen = svp->sv_pathlen;
        if (error = pn_get(oldpath, UIO_SYSSPACE, &oldpn)) {
                nfs_rw_exit(&svp->sv_lock);
                kmem_free(symlink, strlen(symlink) + 1);
                return (error);
        }
        nfs_rw_exit(&svp->sv_lock);
        pn_alloc(&newpn);

        /*
         * Skip over previous components from the oldpath so that the
         * oldpn.pn_path will point to the symlink component. Skip
         * leading slashes and "/./" (no OP_LOOKUP on ".") so that
         * pn_getcompnent can get the component.
         */
        for (i = 1; i < nth; i++) {
                pathname_skipslashdot(&oldpn);
                error = pn_getcomponent(&oldpn, component);
                if (error)
                        goto out;
        }

        /*
         * Copy the old path upto the component right before the symlink
         * if the symlink is not an absolute path.
         */
        if (symlink[0] != '/') {
                addlen = oldpn.pn_path - oldpn.pn_buf;
                bcopy(oldpn.pn_buf, newpn.pn_path, addlen);
                newpn.pn_pathlen += addlen;
                newpn.pn_path += addlen;
                newpn.pn_buf[newpn.pn_pathlen] = '/';
                newpn.pn_pathlen++;
                newpn.pn_path++;
        }

        /* copy the resolved symbolic link text */
        addlen = strlen(symlink);
        if (newpn.pn_pathlen + addlen >= newpn.pn_bufsize) {
                error = ENAMETOOLONG;
                goto out;
        }
        bcopy(symlink, newpn.pn_path, addlen);
        newpn.pn_pathlen += addlen;
        newpn.pn_path += addlen;

        /*
         * Check if there is any remaining path after the symlink component.
         * First, skip the symlink component.
         */
        pathname_skipslashdot(&oldpn);
        if (error = pn_getcomponent(&oldpn, component))
                goto out;

        addlen = pn_pathleft(&oldpn); /* includes counting the slash */

        /*
         * Copy the remaining path to the new pathname if there is any.
         */
        if (addlen > 0) {
                if (newpn.pn_pathlen + addlen >= newpn.pn_bufsize) {
                        error = ENAMETOOLONG;
                        goto out;
                }
                bcopy(oldpn.pn_path, newpn.pn_path, addlen);
                newpn.pn_pathlen += addlen;
        }
        newpn.pn_buf[newpn.pn_pathlen] = '\0';

        /* get the newpath and store it in the servinfo4_t */
        newpath = kmem_alloc(newpn.pn_pathlen + 1, KM_SLEEP);
        bcopy(newpn.pn_buf, newpath, newpn.pn_pathlen);
        newpath[newpn.pn_pathlen] = '\0';

        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
        svp->sv_path = newpath;
        svp->sv_pathlen = strlen(newpath) + 1;
        nfs_rw_exit(&svp->sv_lock);

        kmem_free(oldpath, oldpathlen);
out:
        kmem_free(symlink, strlen(symlink) + 1);
        pn_free(&newpn);
        pn_free(&oldpn);

        return (error);
}

/*
 * This routine updates servinfo4 structure with the new referred server
 * info.
 * nfsfsloc has the location related information
 * fsp has the hostname and pathname info.
 * new path = pathname from referral + part of orig pathname(based on nth).
 */
static void
update_servinfo4(servinfo4_t *svp, fs_location4 *fsp,
    struct nfs_fsl_info *nfsfsloc, char *orig_path, int nth)
{
        struct knetconfig *knconf, *svknconf;
        struct netbuf *saddr;
        sec_data_t      *secdata;
        utf8string *host;
        int i = 0, num_slashes = 0;
        char *p, *spath, *op, *new_path;

        /* Update knconf */
        knconf = svp->sv_knconf;
        free_knconf_contents(knconf);
        bzero(knconf, sizeof (struct knetconfig));
        svknconf = nfsfsloc->knconf;
        knconf->knc_semantics = svknconf->knc_semantics;
        knconf->knc_protofmly = kmem_zalloc(KNC_STRSIZE, KM_SLEEP);
        knconf->knc_proto = kmem_zalloc(KNC_STRSIZE, KM_SLEEP);
        knconf->knc_rdev = svknconf->knc_rdev;
        bcopy(svknconf->knc_protofmly, knconf->knc_protofmly, KNC_STRSIZE);
        bcopy(svknconf->knc_proto, knconf->knc_proto, KNC_STRSIZE);

        /* Update server address */
        saddr = &svp->sv_addr;
        if (saddr->buf != NULL)
                kmem_free(saddr->buf, saddr->maxlen);
        saddr->buf  = kmem_alloc(nfsfsloc->addr->maxlen, KM_SLEEP);
        saddr->len = nfsfsloc->addr->len;
        saddr->maxlen = nfsfsloc->addr->maxlen;
        bcopy(nfsfsloc->addr->buf, saddr->buf, nfsfsloc->addr->len);

        /* Update server name */
        host = fsp->server_val;
        kmem_free(svp->sv_hostname, svp->sv_hostnamelen);
        svp->sv_hostname = kmem_zalloc(host->utf8string_len + 1, KM_SLEEP);
        bcopy(host->utf8string_val, svp->sv_hostname, host->utf8string_len);
        svp->sv_hostname[host->utf8string_len] = '\0';
        svp->sv_hostnamelen = host->utf8string_len + 1;

        /*
         * Update server path.
         * We need to setup proper path here.
         * For ex., If we got a path name serv1:/rp/aaa/bbb
         * where aaa is a referral and points to serv2:/rpool/aa
         * we need to set the path to serv2:/rpool/aa/bbb
         * The first part of this below code generates /rpool/aa
         * and the second part appends /bbb to the server path.
         */
        spath = p = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
        *p++ = '/';
        for (i = 0; i < fsp->rootpath.pathname4_len; i++) {
                component4 *comp;

                comp = &fsp->rootpath.pathname4_val[i];
                /* If no space, null the string and bail */
                if ((p - spath) + comp->utf8string_len + 1 > MAXPATHLEN) {
                        p = spath + MAXPATHLEN - 1;
                        spath[0] = '\0';
                        break;
                }
                bcopy(comp->utf8string_val, p, comp->utf8string_len);
                p += comp->utf8string_len;
                *p++ = '/';
        }
        if (fsp->rootpath.pathname4_len != 0)
                *(p - 1) = '\0';
        else
                *p = '\0';
        p = spath;

        new_path = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
        (void) strlcpy(new_path, p, MAXPATHLEN);
        kmem_free(p, MAXPATHLEN);
        i = strlen(new_path);

        for (op = orig_path; *op; op++) {
                if (*op == '/')
                        num_slashes++;
                if (num_slashes == nth + 2) {
                        while (*op != '\0') {
                                new_path[i] = *op;
                                i++;
                                op++;
                        }
                        break;
                }
        }
        new_path[i] = '\0';

        kmem_free(svp->sv_path, svp->sv_pathlen);
        svp->sv_pathlen = strlen(new_path) + 1;
        svp->sv_path = kmem_alloc(svp->sv_pathlen, KM_SLEEP);
        bcopy(new_path, svp->sv_path, svp->sv_pathlen);
        kmem_free(new_path, MAXPATHLEN);

        /*
         * All the security data is specific to old server.
         * Clean it up except secdata which deals with mount options.
         * We need to inherit that data. Copy secdata into our new servinfo4.
         */
        if (svp->sv_dhsec) {
                sec_clnt_freeinfo(svp->sv_dhsec);
                svp->sv_dhsec = NULL;
        }
        if (svp->sv_save_secinfo &&
            svp->sv_save_secinfo != svp->sv_secinfo) {
                secinfo_free(svp->sv_save_secinfo);
                svp->sv_save_secinfo = NULL;
        }
        if (svp->sv_secinfo) {
                secinfo_free(svp->sv_secinfo);
                svp->sv_secinfo = NULL;
        }
        svp->sv_currsec = NULL;

        secdata = kmem_alloc(sizeof (*secdata), KM_SLEEP);
        *secdata = *svp->sv_secdata;
        secdata->data = NULL;
        if (svp->sv_secdata) {
                sec_clnt_freeinfo(svp->sv_secdata);
                svp->sv_secdata = NULL;
        }
        svp->sv_secdata = secdata;
}

/*
 * Resolve a referral. The referral is in the n+1th component of
 * svp->sv_path and has a parent nfs4 file handle "fh".
 * Upon return, the sv_path will point to the new path that has referral
 * component resolved to its referred path and part of original path.
 * Hostname and other address information is also updated.
 */
int
resolve_referral(mntinfo4_t *mi, servinfo4_t *svp, cred_t *cr, int nth,
    nfs_fh4 *fh)
{
        nfs4_sharedfh_t *sfh;
        struct nfs_fsl_info nfsfsloc;
        nfs4_ga_res_t garp;
        COMPOUND4res_clnt callres;
        fs_location4    *fsp;
        char *nm, *orig_path;
        int orig_pathlen = 0, ret = -1, index;

        if (svp->sv_pathlen <= 0)
                return (ret);

        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
        orig_pathlen = svp->sv_pathlen;
        orig_path = kmem_alloc(orig_pathlen, KM_SLEEP);
        bcopy(svp->sv_path, orig_path, orig_pathlen);
        nm = extract_referral_point(svp->sv_path, nth);
        setup_newsvpath(svp, nth);
        nfs_rw_exit(&svp->sv_lock);

        sfh = sfh4_get(fh, mi);
        index = nfs4_process_referral(mi, sfh, nm, cr,
            &garp, &callres, &nfsfsloc);
        sfh4_rele(&sfh);
        kmem_free(nm, MAXPATHLEN);
        if (index < 0) {
                kmem_free(orig_path, orig_pathlen);
                return (index);
        }

        fsp =  &garp.n4g_ext_res->n4g_fslocations.locations_val[index];
        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
        update_servinfo4(svp, fsp, &nfsfsloc, orig_path, nth);
        nfs_rw_exit(&svp->sv_lock);

        mutex_enter(&mi->mi_lock);
        mi->mi_vfs_referral_loop_cnt++;
        mutex_exit(&mi->mi_lock);

        ret = 0;
bad:
        /* Free up XDR memory allocated in nfs4_process_referral() */
        xdr_free(xdr_nfs_fsl_info, (char *)&nfsfsloc);
        xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&callres);
        kmem_free(orig_path, orig_pathlen);

        return (ret);
}

/*
 * Get the root filehandle for the given filesystem and server, and update
 * svp.
 *
 * If NFS4_GETFH_NEEDSOP is set, then use nfs4_start_fop and nfs4_end_fop
 * to coordinate with recovery.  Otherwise, the caller is assumed to be
 * the recovery thread or have already done a start_fop.
 *
 * Errors are returned by the nfs4_error_t parameter.
 */
static void
nfs4getfh_otw(struct mntinfo4 *mi, servinfo4_t *svp, vtype_t *vtp,
    int flags, cred_t *cr, nfs4_error_t *ep)
{
        COMPOUND4args_clnt args;
        COMPOUND4res_clnt res;
        int doqueue = 1;
        nfs_argop4 *argop;
        nfs_resop4 *resop;
        nfs4_ga_res_t *garp;
        int num_argops;
        lookup4_param_t lookuparg;
        nfs_fh4 *tmpfhp;
        nfs_fh4 *resfhp;
        bool_t needrecov = FALSE;
        nfs4_recov_state_t recov_state;
        int llndx;
        int nthcomp;
        int recovery = !(flags & NFS4_GETFH_NEEDSOP);

        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
        ASSERT(svp->sv_path != NULL);
        if (svp->sv_path[0] == '\0') {
                nfs_rw_exit(&svp->sv_lock);
                nfs4_error_init(ep, EINVAL);
                return;
        }
        nfs_rw_exit(&svp->sv_lock);

        recov_state.rs_flags = 0;
        recov_state.rs_num_retry_despite_err = 0;

recov_retry:
        if (mi->mi_vfs_referral_loop_cnt >= NFS4_REFERRAL_LOOP_MAX) {
                DTRACE_PROBE3(nfs4clnt__debug__referral__loop, mntinfo4 *,
                    mi, servinfo4_t *, svp, char *, "nfs4getfh_otw");
                nfs4_error_init(ep, EINVAL);
                return;
        }
        nfs4_error_zinit(ep);

        if (!recovery) {
                ep->error = nfs4_start_fop(mi, NULL, NULL, OH_MOUNT,
                    &recov_state, NULL);

                /*
                 * If recovery has been started and this request as
                 * initiated by a mount, then we must wait for recovery
                 * to finish before proceeding, otherwise, the error
                 * cleanup would remove data structures needed by the
                 * recovery thread.
                 */
                if (ep->error) {
                        mutex_enter(&mi->mi_lock);
                        if (mi->mi_flags & MI4_MOUNTING) {
                                mi->mi_flags |= MI4_RECOV_FAIL;
                                mi->mi_error = EIO;

                                NFS4_DEBUG(nfs4_client_recov_debug, (CE_NOTE,
                                    "nfs4getfh_otw: waiting 4 recovery\n"));

                                while (mi->mi_flags & MI4_RECOV_ACTIV)
                                        cv_wait(&mi->mi_failover_cv,
                                            &mi->mi_lock);
                        }
                        mutex_exit(&mi->mi_lock);
                        return;
                }

                /*
                 * If the client does not specify a specific flavor to use
                 * and has not gotten a secinfo list from the server yet,
                 * retrieve the secinfo list from the server and use a
                 * flavor from the list to mount.
                 *
                 * If fail to get the secinfo list from the server, then
                 * try the default flavor.
                 */
                if ((svp->sv_flags & SV4_TRYSECDEFAULT) &&
                    svp->sv_secinfo == NULL) {
                        (void) nfs4_secinfo_path(mi, cr, FALSE);
                }
        }

        if (recovery)
                args.ctag = TAG_REMAP_MOUNT;
        else
                args.ctag = TAG_MOUNT;

        lookuparg.l4_getattrs = LKP4_ALL_ATTRIBUTES;
        lookuparg.argsp = &args;
        lookuparg.resp = &res;
        lookuparg.header_len = 2;       /* Putrootfh, getfh */
        lookuparg.trailer_len = 0;
        lookuparg.ga_bits = FATTR4_FSINFO_MASK;
        lookuparg.mi = mi;

        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
        ASSERT(svp->sv_path != NULL);
        llndx = nfs4lookup_setup(svp->sv_path, &lookuparg, 0);
        nfs_rw_exit(&svp->sv_lock);

        argop = args.array;
        num_argops = args.array_len;

        /* choose public or root filehandle */
        if (flags & NFS4_GETFH_PUBLIC)
                argop[0].argop = OP_PUTPUBFH;
        else
                argop[0].argop = OP_PUTROOTFH;

        /* get fh */
        argop[1].argop = OP_GETFH;

        NFS4_DEBUG(nfs4_client_call_debug, (CE_NOTE,
            "nfs4getfh_otw: %s call, mi 0x%p",
            needrecov ? "recov" : "first", (void *)mi));

        rfs4call(mi, &args, &res, cr, &doqueue, RFSCALL_SOFT, ep);

        needrecov = nfs4_needs_recovery(ep, FALSE, mi->mi_vfsp);

        if (needrecov) {
                bool_t abort;

                if (recovery) {
                        nfs4args_lookup_free(argop, num_argops);
                        kmem_free(argop,
                            lookuparg.arglen * sizeof (nfs_argop4));
                        if (!ep->error)
                                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
                        return;
                }

                NFS4_DEBUG(nfs4_client_recov_debug,
                    (CE_NOTE, "nfs4getfh_otw: initiating recovery\n"));

                abort = nfs4_start_recovery(ep, mi, NULL,
                    NULL, NULL, NULL, OP_GETFH, NULL, NULL, NULL);
                if (!ep->error) {
                        ep->error = geterrno4(res.status);
                        xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
                }
                nfs4args_lookup_free(argop, num_argops);
                kmem_free(argop, lookuparg.arglen * sizeof (nfs_argop4));
                nfs4_end_fop(mi, NULL, NULL, OH_MOUNT, &recov_state, needrecov);
                /* have another go? */
                if (abort == FALSE)
                        goto recov_retry;
                return;
        }

        /*
         * No recovery, but check if error is set.
         */
        if (ep->error)  {
                nfs4args_lookup_free(argop, num_argops);
                kmem_free(argop, lookuparg.arglen * sizeof (nfs_argop4));
                if (!recovery)
                        nfs4_end_fop(mi, NULL, NULL, OH_MOUNT, &recov_state,
                            needrecov);
                return;
        }

is_link_err:

        /* for non-recovery errors */
        if (res.status && res.status != NFS4ERR_SYMLINK &&
            res.status != NFS4ERR_MOVED) {
                if (!recovery) {
                        nfs4_end_fop(mi, NULL, NULL, OH_MOUNT, &recov_state,
                            needrecov);
                }
                nfs4args_lookup_free(argop, num_argops);
                kmem_free(argop, lookuparg.arglen * sizeof (nfs_argop4));
                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
                return;
        }

        /*
         * If any intermediate component in the path is a symbolic link,
         * resolve the symlink, then try mount again using the new path.
         */
        if (res.status == NFS4ERR_SYMLINK || res.status == NFS4ERR_MOVED) {
                int where;

                /*
                 * Need to call nfs4_end_op before resolve_sympath to avoid
                 * potential nfs4_start_op deadlock.
                 */
                if (!recovery)
                        nfs4_end_fop(mi, NULL, NULL, OH_MOUNT, &recov_state,
                            needrecov);

                /*
                 * This must be from OP_LOOKUP failure. The (cfh) for this
                 * OP_LOOKUP is a symlink node. Found out where the
                 * OP_GETFH is for the (cfh) that is a symlink node.
                 *
                 * Example:
                 * (mount) PUTROOTFH, GETFH, LOOKUP comp1, GETFH, GETATTR,
                 * LOOKUP comp2, GETFH, GETATTR, LOOKUP comp3, GETFH, GETATTR
                 *
                 * LOOKUP comp3 fails with SYMLINK because comp2 is a symlink.
                 * In this case, where = 7, nthcomp = 2.
                 */
                where = res.array_len - 2;
                ASSERT(where > 0);

                if (res.status == NFS4ERR_SYMLINK) {

                        resop = &res.array[where - 1];
                        ASSERT(resop->resop == OP_GETFH);
                        tmpfhp = &resop->nfs_resop4_u.opgetfh.object;
                        nthcomp = res.array_len/3 - 1;
                        ep->error = resolve_sympath(mi, svp, nthcomp,
                            tmpfhp, cr, flags);

                } else if (res.status == NFS4ERR_MOVED) {

                        resop = &res.array[where - 2];
                        ASSERT(resop->resop == OP_GETFH);
                        tmpfhp = &resop->nfs_resop4_u.opgetfh.object;
                        nthcomp = res.array_len/3 - 1;
                        ep->error = resolve_referral(mi, svp, cr, nthcomp,
                            tmpfhp);
                }

                nfs4args_lookup_free(argop, num_argops);
                kmem_free(argop, lookuparg.arglen * sizeof (nfs_argop4));
                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);

                if (ep->error)
                        return;

                goto recov_retry;
        }

        /* getfh */
        resop = &res.array[res.array_len - 2];
        ASSERT(resop->resop == OP_GETFH);
        resfhp = &resop->nfs_resop4_u.opgetfh.object;

        /* getattr fsinfo res */
        resop++;
        garp = &resop->nfs_resop4_u.opgetattr.ga_res;

        *vtp = garp->n4g_va.va_type;

        mi->mi_fh_expire_type = garp->n4g_ext_res->n4g_fet;

        mutex_enter(&mi->mi_lock);
        if (garp->n4g_ext_res->n4g_pc4.pc4_link_support)
                mi->mi_flags |= MI4_LINK;
        if (garp->n4g_ext_res->n4g_pc4.pc4_symlink_support)
                mi->mi_flags |= MI4_SYMLINK;
        if (garp->n4g_ext_res->n4g_suppattrs & FATTR4_ACL_MASK)
                mi->mi_flags |= MI4_ACL;
        mutex_exit(&mi->mi_lock);

        if (garp->n4g_ext_res->n4g_maxread == 0)
                mi->mi_tsize =
                    MIN(MAXBSIZE, mi->mi_tsize);
        else
                mi->mi_tsize =
                    MIN(garp->n4g_ext_res->n4g_maxread,
                    mi->mi_tsize);

        if (garp->n4g_ext_res->n4g_maxwrite == 0)
                mi->mi_stsize =
                    MIN(MAXBSIZE, mi->mi_stsize);
        else
                mi->mi_stsize =
                    MIN(garp->n4g_ext_res->n4g_maxwrite,
                    mi->mi_stsize);

        if (garp->n4g_ext_res->n4g_maxfilesize != 0)
                mi->mi_maxfilesize =
                    MIN(garp->n4g_ext_res->n4g_maxfilesize,
                    mi->mi_maxfilesize);

        /*
         * If the final component is a a symbolic link, resolve the symlink,
         * then try mount again using the new path.
         *
         * Assume no symbolic link for root filesysm "/".
         */
        if (*vtp == VLNK) {
                /*
                 * nthcomp is the total result length minus
                 * the 1st 2 OPs (PUTROOTFH, GETFH),
                 * then divided by 3 (LOOKUP,GETFH,GETATTR)
                 *
                 * e.g. PUTROOTFH GETFH LOOKUP 1st-comp GETFH GETATTR
                 *      LOOKUP 2nd-comp GETFH GETATTR
                 *
                 *      (8 - 2)/3 = 2
                 */
                nthcomp = (res.array_len - 2)/3;

                /*
                 * Need to call nfs4_end_op before resolve_sympath to avoid
                 * potential nfs4_start_op deadlock. See RFE 4777612.
                 */
                if (!recovery)
                        nfs4_end_fop(mi, NULL, NULL, OH_MOUNT, &recov_state,
                            needrecov);

                ep->error = resolve_sympath(mi, svp, nthcomp, resfhp, cr,
                    flags);

                nfs4args_lookup_free(argop, num_argops);
                kmem_free(argop, lookuparg.arglen * sizeof (nfs_argop4));
                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);

                if (ep->error)
                        return;

                goto recov_retry;
        }

        /*
         * We need to figure out where in the compound the getfh
         * for the parent directory is. If the object to be mounted is
         * the root, then there is no lookup at all:
         * PUTROOTFH, GETFH.
         * If the object to be mounted is in the root, then the compound is:
         * PUTROOTFH, GETFH, LOOKUP, GETFH, GETATTR.
         * In either of these cases, the index of the GETFH is 1.
         * If it is not at the root, then it's something like:
         * PUTROOTFH, GETFH, LOOKUP, GETFH, GETATTR,
         * LOOKUP, GETFH, GETATTR
         * In this case, the index is llndx (last lookup index) - 2.
         */
        if (llndx == -1 || llndx == 2)
                resop = &res.array[1];
        else {
                ASSERT(llndx > 2);
                resop = &res.array[llndx-2];
        }

        ASSERT(resop->resop == OP_GETFH);
        tmpfhp = &resop->nfs_resop4_u.opgetfh.object;

        /* save the filehandles for the replica */
        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
        ASSERT(tmpfhp->nfs_fh4_len <= NFS4_FHSIZE);
        svp->sv_pfhandle.fh_len = tmpfhp->nfs_fh4_len;
        bcopy(tmpfhp->nfs_fh4_val, svp->sv_pfhandle.fh_buf,
            tmpfhp->nfs_fh4_len);
        ASSERT(resfhp->nfs_fh4_len <= NFS4_FHSIZE);
        svp->sv_fhandle.fh_len = resfhp->nfs_fh4_len;
        bcopy(resfhp->nfs_fh4_val, svp->sv_fhandle.fh_buf, resfhp->nfs_fh4_len);

        /* initialize fsid and supp_attrs for server fs */
        svp->sv_fsid = garp->n4g_fsid;
        svp->sv_supp_attrs =
            garp->n4g_ext_res->n4g_suppattrs | FATTR4_MANDATTR_MASK;

        nfs_rw_exit(&svp->sv_lock);
        nfs4args_lookup_free(argop, num_argops);
        kmem_free(argop, lookuparg.arglen * sizeof (nfs_argop4));
        xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
        if (!recovery)
                nfs4_end_fop(mi, NULL, NULL, OH_MOUNT, &recov_state, needrecov);
}

/*
 * Save a copy of Servinfo4_t structure.
 * We might need when there is a failure in getting file handle
 * in case of a referral to replace servinfo4 struct and try again.
 */
static struct servinfo4 *
copy_svp(servinfo4_t *nsvp)
{
        servinfo4_t *svp = NULL;
        struct knetconfig *sknconf, *tknconf;
        struct netbuf *saddr, *taddr;

        svp = kmem_zalloc(sizeof (*svp), KM_SLEEP);
        nfs_rw_init(&svp->sv_lock, NULL, RW_DEFAULT, NULL);
        svp->sv_flags = nsvp->sv_flags;
        svp->sv_fsid = nsvp->sv_fsid;
        svp->sv_hostnamelen = nsvp->sv_hostnamelen;
        svp->sv_pathlen = nsvp->sv_pathlen;
        svp->sv_supp_attrs = nsvp->sv_supp_attrs;

        svp->sv_path = kmem_alloc(svp->sv_pathlen, KM_SLEEP);
        svp->sv_hostname = kmem_alloc(svp->sv_hostnamelen, KM_SLEEP);
        bcopy(nsvp->sv_hostname, svp->sv_hostname, svp->sv_hostnamelen);
        bcopy(nsvp->sv_path, svp->sv_path, svp->sv_pathlen);

        saddr = &nsvp->sv_addr;
        taddr = &svp->sv_addr;
        taddr->maxlen = saddr->maxlen;
        taddr->len = saddr->len;
        if (saddr->len > 0) {
                taddr->buf = kmem_zalloc(saddr->maxlen, KM_SLEEP);
                bcopy(saddr->buf, taddr->buf, saddr->len);
        }

        svp->sv_knconf = kmem_zalloc(sizeof (struct knetconfig), KM_SLEEP);
        sknconf = nsvp->sv_knconf;
        tknconf = svp->sv_knconf;
        tknconf->knc_semantics = sknconf->knc_semantics;
        tknconf->knc_rdev = sknconf->knc_rdev;
        if (sknconf->knc_proto != NULL) {
                tknconf->knc_proto = kmem_zalloc(KNC_STRSIZE, KM_SLEEP);
                bcopy(sknconf->knc_proto, (char *)tknconf->knc_proto,
                    KNC_STRSIZE);
        }
        if (sknconf->knc_protofmly != NULL) {
                tknconf->knc_protofmly = kmem_zalloc(KNC_STRSIZE, KM_SLEEP);
                bcopy(sknconf->knc_protofmly, (char *)tknconf->knc_protofmly,
                    KNC_STRSIZE);
        }

        if (nsvp->sv_origknconf != NULL) {
                svp->sv_origknconf = kmem_zalloc(sizeof (struct knetconfig),
                    KM_SLEEP);
                sknconf = nsvp->sv_origknconf;
                tknconf = svp->sv_origknconf;
                tknconf->knc_semantics = sknconf->knc_semantics;
                tknconf->knc_rdev = sknconf->knc_rdev;
                if (sknconf->knc_proto != NULL) {
                        tknconf->knc_proto = kmem_zalloc(KNC_STRSIZE, KM_SLEEP);
                        bcopy(sknconf->knc_proto, (char *)tknconf->knc_proto,
                            KNC_STRSIZE);
                }
                if (sknconf->knc_protofmly != NULL) {
                        tknconf->knc_protofmly = kmem_zalloc(KNC_STRSIZE,
                            KM_SLEEP);
                        bcopy(sknconf->knc_protofmly,
                            (char *)tknconf->knc_protofmly, KNC_STRSIZE);
                }
        }

        svp->sv_secdata = copy_sec_data(nsvp->sv_secdata);
        svp->sv_dhsec = copy_sec_data(svp->sv_dhsec);
        /*
         * Rest of the security information is not copied as they are built
         * with the information available from secdata and dhsec.
         */
        svp->sv_next = NULL;

        return (svp);
}

servinfo4_t *
restore_svp(mntinfo4_t *mi, servinfo4_t *svp, servinfo4_t *origsvp)
{
        servinfo4_t *srvnext, *tmpsrv;

        if (strcmp(svp->sv_hostname, origsvp->sv_hostname) != 0) {
                /*
                 * Since the hostname changed, we must be dealing
                 * with a referral, and the lookup failed.  We will
                 * restore the whole servinfo4_t to what it was before.
                 */
                srvnext = svp->sv_next;
                svp->sv_next = NULL;
                tmpsrv = copy_svp(origsvp);
                sv4_free(svp);
                svp = tmpsrv;
                svp->sv_next = srvnext;
                mutex_enter(&mi->mi_lock);
                mi->mi_servers = svp;
                mi->mi_curr_serv = svp;
                mutex_exit(&mi->mi_lock);

        } else if (origsvp->sv_pathlen != svp->sv_pathlen) {

                /*
                 * For symlink case: restore original path because
                 * it might have contained symlinks that were
                 * expanded by nfsgetfh_otw before the failure occurred.
                 */
                (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
                kmem_free(svp->sv_path, svp->sv_pathlen);
                svp->sv_path =
                    kmem_alloc(origsvp->sv_pathlen, KM_SLEEP);
                svp->sv_pathlen = origsvp->sv_pathlen;
                bcopy(origsvp->sv_path, svp->sv_path,
                    origsvp->sv_pathlen);
                nfs_rw_exit(&svp->sv_lock);
        }
        return (svp);
}

static ushort_t nfs4_max_threads = 8;   /* max number of active async threads */
uint_t nfs4_bsize = 32 * 1024;  /* client `block' size */
static uint_t nfs4_async_clusters = 1;  /* # of reqs from each async queue */
static uint_t nfs4_cots_timeo = NFS_COTS_TIMEO;

/*
 * Remap the root filehandle for the given filesystem.
 *
 * results returned via the nfs4_error_t parameter.
 */
void
nfs4_remap_root(mntinfo4_t *mi, nfs4_error_t *ep, int flags)
{
        struct servinfo4 *svp, *origsvp;
        vtype_t vtype;
        nfs_fh4 rootfh;
        int getfh_flags;
        int num_retry;

        mutex_enter(&mi->mi_lock);

remap_retry:
        svp = mi->mi_curr_serv;
        getfh_flags =
            (flags & NFS4_REMAP_NEEDSOP) ? NFS4_GETFH_NEEDSOP : 0;
        getfh_flags |=
            (mi->mi_flags & MI4_PUBLIC) ? NFS4_GETFH_PUBLIC : 0;
        mutex_exit(&mi->mi_lock);

        /*
         * Just in case server path being mounted contains
         * symlinks and fails w/STALE, save the initial sv_path
         * so we can redrive the initial mount compound with the
         * initial sv_path -- not a symlink-expanded version.
         *
         * This could only happen if a symlink was expanded
         * and the expanded mount compound failed stale.  Because
         * it could be the case that the symlink was removed at
         * the server (and replaced with another symlink/dir,
         * we need to use the initial sv_path when attempting
         * to re-lookup everything and recover.
         */
        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
        origsvp = copy_svp(svp);
        nfs_rw_exit(&svp->sv_lock);

        num_retry = nfs4_max_mount_retry;

        do {
                /*
                 * Get the root fh from the server.  Retry nfs4_max_mount_retry
                 * (2) times if it fails with STALE since the recovery
                 * infrastructure doesn't do STALE recovery for components
                 * of the server path to the object being mounted.
                 */
                nfs4getfh_otw(mi, svp, &vtype, getfh_flags, CRED(), ep);

                if (ep->error == 0 && ep->stat == NFS4_OK)
                        break;

                /*
                 * For some reason, the mount compound failed.  Before
                 * retrying, we need to restore original conditions.
                 */
                svp = restore_svp(mi, svp, origsvp);

        } while (num_retry-- > 0);

        sv4_free(origsvp);

        if (ep->error != 0 || ep->stat != 0) {
                return;
        }

        if (vtype != VNON && vtype != mi->mi_type) {
                /* shouldn't happen */
                zcmn_err(mi->mi_zone->zone_id, CE_WARN,
                    "nfs4_remap_root: server root vnode type (%d) doesn't "
                    "match mount info (%d)", vtype, mi->mi_type);
        }

        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
        rootfh.nfs_fh4_val = svp->sv_fhandle.fh_buf;
        rootfh.nfs_fh4_len = svp->sv_fhandle.fh_len;
        nfs_rw_exit(&svp->sv_lock);
        sfh4_update(mi->mi_rootfh, &rootfh);

        /*
         * It's possible that recovery took place on the filesystem
         * and the server has been updated between the time we did
         * the nfs4getfh_otw and now. Re-drive the otw operation
         * to make sure we have a good fh.
         */
        mutex_enter(&mi->mi_lock);
        if (mi->mi_curr_serv != svp)
                goto remap_retry;

        mutex_exit(&mi->mi_lock);
}

static int
nfs4rootvp(vnode_t **rtvpp, vfs_t *vfsp, struct servinfo4 *svp_head,
    int flags, cred_t *cr, zone_t *zone)
{
        vnode_t *rtvp = NULL;
        mntinfo4_t *mi;
        dev_t nfs_dev;
        int error = 0;
        rnode4_t *rp;
        int i, len;
        struct vattr va;
        vtype_t vtype = VNON;
        vtype_t tmp_vtype = VNON;
        struct servinfo4 *firstsvp = NULL, *svp = svp_head;
        nfs4_oo_hash_bucket_t *bucketp;
        nfs_fh4 fh;
        char *droptext = "";
        struct nfs_stats *nfsstatsp;
        nfs4_fname_t *mfname;
        nfs4_error_t e;
        int num_retry, removed;
        cred_t *lcr = NULL, *tcr = cr;
        struct servinfo4 *origsvp;
        char *resource;

        nfsstatsp = zone_getspecific(nfsstat_zone_key, nfs_zone());
        ASSERT(nfsstatsp != NULL);

        ASSERT(nfs_zone() == zone);
        ASSERT(crgetref(cr));

        /*
         * Create a mount record and link it to the vfs struct.
         */
        mi = kmem_zalloc(sizeof (*mi), KM_SLEEP);
        mutex_init(&mi->mi_lock, NULL, MUTEX_DEFAULT, NULL);
        nfs_rw_init(&mi->mi_recovlock, NULL, RW_DEFAULT, NULL);
        nfs_rw_init(&mi->mi_rename_lock, NULL, RW_DEFAULT, NULL);
        nfs_rw_init(&mi->mi_fh_lock, NULL, RW_DEFAULT, NULL);

        if (!(flags & NFSMNT_SOFT))
                mi->mi_flags |= MI4_HARD;
        if ((flags & NFSMNT_NOPRINT))
                mi->mi_flags |= MI4_NOPRINT;
        if (flags & NFSMNT_INT)
                mi->mi_flags |= MI4_INT;
        if (flags & NFSMNT_PUBLIC)
                mi->mi_flags |= MI4_PUBLIC;
        if (flags & NFSMNT_MIRRORMOUNT)
                mi->mi_flags |= MI4_MIRRORMOUNT;
        if (flags & NFSMNT_REFERRAL)
                mi->mi_flags |= MI4_REFERRAL;
        mi->mi_retrans = NFS_RETRIES;
        if (svp->sv_knconf->knc_semantics == NC_TPI_COTS_ORD ||
            svp->sv_knconf->knc_semantics == NC_TPI_COTS)
                mi->mi_timeo = nfs4_cots_timeo;
        else
                mi->mi_timeo = NFS_TIMEO;
        mi->mi_prog = NFS_PROGRAM;
        mi->mi_vers = NFS_V4;
        mi->mi_rfsnames = rfsnames_v4;
        mi->mi_reqs = nfsstatsp->nfs_stats_v4.rfsreqcnt_ptr;
        cv_init(&mi->mi_failover_cv, NULL, CV_DEFAULT, NULL);
        mi->mi_servers = svp;
        mi->mi_curr_serv = svp;
        mi->mi_acregmin = SEC2HR(ACREGMIN);
        mi->mi_acregmax = SEC2HR(ACREGMAX);
        mi->mi_acdirmin = SEC2HR(ACDIRMIN);
        mi->mi_acdirmax = SEC2HR(ACDIRMAX);
        mi->mi_fh_expire_type = FH4_PERSISTENT;
        mi->mi_clientid_next = NULL;
        mi->mi_clientid_prev = NULL;
        mi->mi_srv = NULL;
        mi->mi_grace_wait = 0;
        mi->mi_error = 0;
        mi->mi_srvsettime = 0;
        mi->mi_srvset_cnt = 0;

        mi->mi_count = 1;

        mi->mi_tsize = nfs4_tsize(svp->sv_knconf);
        mi->mi_stsize = mi->mi_tsize;

        if (flags & NFSMNT_DIRECTIO)
                mi->mi_flags |= MI4_DIRECTIO;

        mi->mi_flags |= MI4_MOUNTING;

        /*
         * Make a vfs struct for nfs.  We do this here instead of below
         * because rtvp needs a vfs before we can do a getattr on it.
         *
         * Assign a unique device id to the mount
         */
        mutex_enter(&nfs_minor_lock);
        do {
                nfs_minor = (nfs_minor + 1) & MAXMIN32;
                nfs_dev = makedevice(nfs_major, nfs_minor);
        } while (vfs_devismounted(nfs_dev));
        mutex_exit(&nfs_minor_lock);

        vfsp->vfs_dev = nfs_dev;
        vfs_make_fsid(&vfsp->vfs_fsid, nfs_dev, nfs4fstyp);
        vfsp->vfs_data = (caddr_t)mi;
        vfsp->vfs_fstype = nfsfstyp;
        vfsp->vfs_bsize = nfs4_bsize;

        /*
         * Initialize fields used to support async putpage operations.
         */
        for (i = 0; i < NFS4_ASYNC_TYPES; i++)
                mi->mi_async_clusters[i] = nfs4_async_clusters;
        mi->mi_async_init_clusters = nfs4_async_clusters;
        mi->mi_async_curr[NFS4_ASYNC_QUEUE] =
            mi->mi_async_curr[NFS4_ASYNC_PGOPS_QUEUE] = &mi->mi_async_reqs[0];
        mi->mi_max_threads = nfs4_max_threads;
        mutex_init(&mi->mi_async_lock, NULL, MUTEX_DEFAULT, NULL);
        cv_init(&mi->mi_async_reqs_cv, NULL, CV_DEFAULT, NULL);
        cv_init(&mi->mi_async_work_cv[NFS4_ASYNC_QUEUE], NULL, CV_DEFAULT,
            NULL);
        cv_init(&mi->mi_async_work_cv[NFS4_ASYNC_PGOPS_QUEUE], NULL,
            CV_DEFAULT, NULL);
        cv_init(&mi->mi_async_cv, NULL, CV_DEFAULT, NULL);
        cv_init(&mi->mi_inact_req_cv, NULL, CV_DEFAULT, NULL);

        mi->mi_vfsp = vfsp;
        mi->mi_zone = zone;
        zone_init_ref(&mi->mi_zone_ref);
        zone_hold_ref(zone, &mi->mi_zone_ref, ZONE_REF_NFSV4);
        nfs4_mi_zonelist_add(mi);

        /*
         * Initialize the <open owner/cred> hash table.
         */
        for (i = 0; i < NFS4_NUM_OO_BUCKETS; i++) {
                bucketp = &(mi->mi_oo_list[i]);
                mutex_init(&bucketp->b_lock, NULL, MUTEX_DEFAULT, NULL);
                list_create(&bucketp->b_oo_hash_list,
                    sizeof (nfs4_open_owner_t),
                    offsetof(nfs4_open_owner_t, oo_hash_node));
        }

        /*
         * Initialize the freed open owner list.
         */
        mi->mi_foo_num = 0;
        mi->mi_foo_max = NFS4_NUM_FREED_OPEN_OWNERS;
        list_create(&mi->mi_foo_list, sizeof (nfs4_open_owner_t),
            offsetof(nfs4_open_owner_t, oo_foo_node));

        list_create(&mi->mi_lost_state, sizeof (nfs4_lost_rqst_t),
            offsetof(nfs4_lost_rqst_t, lr_node));

        list_create(&mi->mi_bseqid_list, sizeof (nfs4_bseqid_entry_t),
            offsetof(nfs4_bseqid_entry_t, bs_node));

        /*
         * Initialize the msg buffer.
         */
        list_create(&mi->mi_msg_list, sizeof (nfs4_debug_msg_t),
            offsetof(nfs4_debug_msg_t, msg_node));
        mi->mi_msg_count = 0;
        mutex_init(&mi->mi_msg_list_lock, NULL, MUTEX_DEFAULT, NULL);

        /*
         * Initialize kstats
         */
        nfs4_mnt_kstat_init(vfsp);

        /*
         * Initialize the shared filehandle pool.
         */
        sfh4_createtab(&mi->mi_filehandles);

        /*
         * Save server path we're attempting to mount.
         */
        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
        origsvp = copy_svp(svp);
        nfs_rw_exit(&svp->sv_lock);

        /*
         * Make the GETFH call to get root fh for each replica.
         */
        if (svp_head->sv_next)
                droptext = ", dropping replica";

        /*
         * If the uid is set then set the creds for secure mounts
         * by proxy processes such as automountd.
         */
        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
        if (svp->sv_secdata->uid != 0 &&
            svp->sv_secdata->rpcflavor == RPCSEC_GSS) {
                lcr = crdup(cr);
                (void) crsetugid(lcr, svp->sv_secdata->uid, crgetgid(cr));
                tcr = lcr;
        }
        nfs_rw_exit(&svp->sv_lock);
        for (svp = svp_head; svp; svp = svp->sv_next) {
                if (nfs4_chkdup_servinfo4(svp_head, svp)) {
                        nfs_cmn_err(error, CE_WARN,
                            VERS_MSG "Host %s is a duplicate%s",
                            svp->sv_hostname, droptext);
                        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
                        svp->sv_flags |= SV4_NOTINUSE;
                        nfs_rw_exit(&svp->sv_lock);
                        continue;
                }
                mi->mi_curr_serv = svp;

                /*
                 * Just in case server path being mounted contains
                 * symlinks and fails w/STALE, save the initial sv_path
                 * so we can redrive the initial mount compound with the
                 * initial sv_path -- not a symlink-expanded version.
                 *
                 * This could only happen if a symlink was expanded
                 * and the expanded mount compound failed stale.  Because
                 * it could be the case that the symlink was removed at
                 * the server (and replaced with another symlink/dir,
                 * we need to use the initial sv_path when attempting
                 * to re-lookup everything and recover.
                 *
                 * Other mount errors should evenutally be handled here also
                 * (NFS4ERR_DELAY, NFS4ERR_RESOURCE).  For now, all mount
                 * failures will result in mount being redriven a few times.
                 */
                num_retry = nfs4_max_mount_retry;
                do {
                        nfs4getfh_otw(mi, svp, &tmp_vtype,
                            ((flags & NFSMNT_PUBLIC) ? NFS4_GETFH_PUBLIC : 0) |
                            NFS4_GETFH_NEEDSOP, tcr, &e);

                        if (e.error == 0 && e.stat == NFS4_OK)
                                break;

                        /*
                         * For some reason, the mount compound failed.  Before
                         * retrying, we need to restore original conditions.
                         */
                        svp = restore_svp(mi, svp, origsvp);
                        svp_head = svp;

                } while (num_retry-- > 0);
                error = e.error ? e.error : geterrno4(e.stat);
                if (error) {
                        nfs_cmn_err(error, CE_WARN,
                            VERS_MSG "initial call to %s failed%s: %m",
                            svp->sv_hostname, droptext);
                        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
                        svp->sv_flags |= SV4_NOTINUSE;
                        nfs_rw_exit(&svp->sv_lock);
                        mi->mi_flags &= ~MI4_RECOV_FAIL;
                        mi->mi_error = 0;
                        continue;
                }

                if (tmp_vtype == VBAD) {
                        zcmn_err(mi->mi_zone->zone_id, CE_WARN,
                            VERS_MSG "%s returned a bad file type for "
                            "root%s", svp->sv_hostname, droptext);
                        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
                        svp->sv_flags |= SV4_NOTINUSE;
                        nfs_rw_exit(&svp->sv_lock);
                        continue;
                }

                if (vtype == VNON) {
                        vtype = tmp_vtype;
                } else if (vtype != tmp_vtype) {
                        zcmn_err(mi->mi_zone->zone_id, CE_WARN,
                            VERS_MSG "%s returned a different file type "
                            "for root%s", svp->sv_hostname, droptext);
                        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
                        svp->sv_flags |= SV4_NOTINUSE;
                        nfs_rw_exit(&svp->sv_lock);
                        continue;
                }
                if (firstsvp == NULL)
                        firstsvp = svp;
        }

        if (firstsvp == NULL) {
                if (error == 0)
                        error = ENOENT;
                goto bad;
        }

        mi->mi_curr_serv = svp = firstsvp;
        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
        ASSERT((mi->mi_curr_serv->sv_flags & SV4_NOTINUSE) == 0);
        fh.nfs_fh4_len = svp->sv_fhandle.fh_len;
        fh.nfs_fh4_val = svp->sv_fhandle.fh_buf;
        mi->mi_rootfh = sfh4_get(&fh, mi);
        fh.nfs_fh4_len = svp->sv_pfhandle.fh_len;
        fh.nfs_fh4_val = svp->sv_pfhandle.fh_buf;
        mi->mi_srvparentfh = sfh4_get(&fh, mi);
        nfs_rw_exit(&svp->sv_lock);

        /*
         * Get the fname for filesystem root.
         */
        mi->mi_fname = fn_get(NULL, ".", mi->mi_rootfh);
        mfname = mi->mi_fname;
        fn_hold(mfname);

        /*
         * Make the root vnode without attributes.
         */
        rtvp = makenfs4node_by_fh(mi->mi_rootfh, NULL,
            &mfname, NULL, mi, cr, gethrtime());
        rtvp->v_type = vtype;

        mi->mi_curread = mi->mi_tsize;
        mi->mi_curwrite = mi->mi_stsize;

        /*
         * Start the manager thread responsible for handling async worker
         * threads.
         */
        MI4_HOLD(mi);
        VFS_HOLD(vfsp); /* add reference for thread */
        mi->mi_manager_thread = zthread_create(NULL, 0, nfs4_async_manager,
            vfsp, 0, minclsyspri);
        ASSERT(mi->mi_manager_thread != NULL);

        /*
         * Create the thread that handles over-the-wire calls for
         * fop_inactive.
         * This needs to happen after the manager thread is created.
         */
        MI4_HOLD(mi);
        mi->mi_inactive_thread = zthread_create(NULL, 0, nfs4_inactive_thread,
            mi, 0, minclsyspri);
        ASSERT(mi->mi_inactive_thread != NULL);

        /* If we didn't get a type, get one now */
        if (rtvp->v_type == VNON) {
                va.va_mask = AT_TYPE;
                error = nfs4getattr(rtvp, &va, tcr);
                if (error)
                        goto bad;
                rtvp->v_type = va.va_type;
        }

        mi->mi_type = rtvp->v_type;

        mutex_enter(&mi->mi_lock);
        mi->mi_flags &= ~MI4_MOUNTING;
        mutex_exit(&mi->mi_lock);

        /* Update VFS with new server and path info */
        if ((strcmp(svp->sv_hostname, origsvp->sv_hostname) != 0) ||
            (strcmp(svp->sv_path, origsvp->sv_path) != 0)) {
                len = svp->sv_hostnamelen + svp->sv_pathlen;
                resource = kmem_zalloc(len, KM_SLEEP);
                (void) strcat(resource, svp->sv_hostname);
                (void) strcat(resource, ":");
                (void) strcat(resource, svp->sv_path);
                vfs_setresource(vfsp, resource, 0);
                kmem_free(resource, len);
        }

        sv4_free(origsvp);
        *rtvpp = rtvp;
        if (lcr != NULL)
                crfree(lcr);

        return (0);
bad:
        /*
         * An error occurred somewhere, need to clean up...
         */
        if (lcr != NULL)
                crfree(lcr);

        if (rtvp != NULL) {
                /*
                 * We need to release our reference to the root vnode and
                 * destroy the mntinfo4 struct that we just created.
                 */
                rp = VTOR4(rtvp);
                if (rp->r_flags & R4HASHED)
                        rp4_rmhash(rp);
                VN_RELE(rtvp);
        }
        nfs4_async_stop(vfsp);
        nfs4_async_manager_stop(vfsp);
        removed = nfs4_mi_zonelist_remove(mi);
        if (removed)
                zone_rele_ref(&mi->mi_zone_ref, ZONE_REF_NFSV4);

        /*
         * This releases the initial "hold" of the mi since it will never
         * be referenced by the vfsp.  Also, when mount returns to vfs.c
         * with an error, the vfsp will be destroyed, not rele'd.
         */
        MI4_RELE(mi);

        if (origsvp != NULL)
                sv4_free(origsvp);

        *rtvpp = NULL;
        return (error);
}

/*
 * vfs operations
 */
static int
nfs4_unmount(vfs_t *vfsp, int flag, cred_t *cr)
{
        mntinfo4_t              *mi;
        ushort_t                omax;
        int                     removed;

        bool_t                  must_unlock;

        nfs4_ephemeral_tree_t   *eph_tree;

        if (secpolicy_fs_unmount(cr, vfsp) != 0)
                return (EPERM);

        mi = VFTOMI4(vfsp);

        if (flag & MS_FORCE) {
                vfsp->vfs_flag |= VFS_UNMOUNTED;
                if (nfs_zone() != mi->mi_zone) {
                        /*
                         * If the request is coming from the wrong zone,
                         * we don't want to create any new threads, and
                         * performance is not a concern.  Do everything
                         * inline.
                         */
                        NFS4_DEBUG(nfs4_client_zone_debug, (CE_NOTE,
                            "nfs4_unmount x-zone forced unmount of vfs %p\n",
                            (void *)vfsp));
                        nfs4_free_mount(vfsp, flag, cr);
                } else {
                        /*
                         * Free data structures asynchronously, to avoid
                         * blocking the current thread (for performance
                         * reasons only).
                         */
                        async_free_mount(vfsp, flag, cr);
                }

                return (0);
        }

        /*
         * Wait until all asynchronous putpage operations on
         * this file system are complete before flushing rnodes
         * from the cache.
         */
        omax = mi->mi_max_threads;
        if (nfs4_async_stop_sig(vfsp))
                return (EINTR);

        r4flush(vfsp, cr);

        /*
         * About the only reason that this would fail would be
         * that the harvester is already busy tearing down this
         * node. So we fail back to the caller and let them try
         * again when needed.
         */
        if (nfs4_ephemeral_umount(mi, flag, cr,
            &must_unlock, &eph_tree)) {
                ASSERT(must_unlock == FALSE);
                mutex_enter(&mi->mi_async_lock);
                mi->mi_max_threads = omax;
                mutex_exit(&mi->mi_async_lock);

                return (EBUSY);
        }

        /*
         * If there are any active vnodes on this file system,
         * then the file system is busy and can't be unmounted.
         */
        if (check_rtable4(vfsp)) {
                nfs4_ephemeral_umount_unlock(&must_unlock, &eph_tree);

                mutex_enter(&mi->mi_async_lock);
                mi->mi_max_threads = omax;
                mutex_exit(&mi->mi_async_lock);

                return (EBUSY);
        }

        /*
         * The unmount can't fail from now on, so record any
         * ephemeral changes.
         */
        nfs4_ephemeral_umount_activate(mi, &must_unlock, &eph_tree);

        /*
         * There are no active files that could require over-the-wire
         * calls to the server, so stop the async manager and the
         * inactive thread.
         */
        nfs4_async_manager_stop(vfsp);

        /*
         * Destroy all rnodes belonging to this file system from the
         * rnode hash queues and purge any resources allocated to
         * them.
         */
        destroy_rtable4(vfsp, cr);
        vfsp->vfs_flag |= VFS_UNMOUNTED;

        nfs4_remove_mi_from_server(mi, NULL);
        removed = nfs4_mi_zonelist_remove(mi);
        if (removed)
                zone_rele_ref(&mi->mi_zone_ref, ZONE_REF_NFSV4);

        return (0);
}

/*
 * find root of nfs
 */
static int
nfs4_root(vfs_t *vfsp, vnode_t **vpp)
{
        mntinfo4_t *mi;
        vnode_t *vp;
        nfs4_fname_t *mfname;
        servinfo4_t *svp;

        mi = VFTOMI4(vfsp);

        if (nfs_zone() != mi->mi_zone)
                return (EPERM);

        svp = mi->mi_curr_serv;
        if (svp) {
                (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
                if (svp->sv_flags & SV4_ROOT_STALE) {
                        nfs_rw_exit(&svp->sv_lock);

                        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_WRITER, 0);
                        if (svp->sv_flags & SV4_ROOT_STALE) {
                                svp->sv_flags &= ~SV4_ROOT_STALE;
                                nfs_rw_exit(&svp->sv_lock);
                                return (ENOENT);
                        }
                        nfs_rw_exit(&svp->sv_lock);
                } else
                        nfs_rw_exit(&svp->sv_lock);
        }

        mfname = mi->mi_fname;
        fn_hold(mfname);
        vp = makenfs4node_by_fh(mi->mi_rootfh, NULL, &mfname, NULL,
            VFTOMI4(vfsp), CRED(), gethrtime());

        if (VTOR4(vp)->r_flags & R4STALE) {
                VN_RELE(vp);
                return (ENOENT);
        }

        ASSERT(vp->v_type == VNON || vp->v_type == mi->mi_type);

        vp->v_type = mi->mi_type;

        *vpp = vp;

        return (0);
}

static int
nfs4_statfs_otw(vnode_t *vp, struct statvfs64 *sbp, cred_t *cr)
{
        int error;
        nfs4_ga_res_t gar;
        nfs4_ga_ext_res_t ger;

        gar.n4g_ext_res = &ger;

        if (error = nfs4_attr_otw(vp, TAG_FSINFO, &gar,
            NFS4_STATFS_ATTR_MASK, cr))
                return (error);

        *sbp = gar.n4g_ext_res->n4g_sb;

        return (0);
}

/*
 * Get file system statistics.
 */
static int
nfs4_statvfs(vfs_t *vfsp, struct statvfs64 *sbp)
{
        int error;
        vnode_t *vp;
        cred_t *cr;

        error = nfs4_root(vfsp, &vp);
        if (error)
                return (error);

        cr = CRED();

        error = nfs4_statfs_otw(vp, sbp, cr);
        if (!error) {
                (void) strncpy(sbp->f_basetype,
                    vfssw[vfsp->vfs_fstype].vsw_name, FSTYPSZ);
                sbp->f_flag = vf_to_stf(vfsp->vfs_flag);
        } else {
                nfs4_purge_stale_fh(error, vp, cr);
        }

        VN_RELE(vp);

        return (error);
}

static kmutex_t nfs4_syncbusy;

/*
 * Flush dirty nfs files for file system vfsp.
 * If vfsp == NULL, all nfs files are flushed.
 *
 * SYNC_CLOSE in flag is passed to us to
 * indicate that we are shutting down and or
 * rebooting.
 */
static int
nfs4_sync(vfs_t *vfsp, short flag, cred_t *cr)
{
        /*
         * Cross-zone calls are OK here, since this translates to a
         * fop_putpage(B_ASYNC), which gets picked up by the right zone.
         */
        if (!(flag & SYNC_ATTR) && mutex_tryenter(&nfs4_syncbusy) != 0) {
                r4flush(vfsp, cr);
                mutex_exit(&nfs4_syncbusy);
        }

        /*
         * if SYNC_CLOSE is set then we know that
         * the system is rebooting, mark the mntinfo
         * for later examination.
         */
        if (vfsp && (flag & SYNC_CLOSE)) {
                mntinfo4_t *mi;

                mi = VFTOMI4(vfsp);
                if (!(mi->mi_flags & MI4_SHUTDOWN)) {
                        mutex_enter(&mi->mi_lock);
                        mi->mi_flags |= MI4_SHUTDOWN;
                        mutex_exit(&mi->mi_lock);
                }
        }
        return (0);
}

/*
 * vget is difficult, if not impossible, to support in v4 because we don't
 * know the parent directory or name, which makes it impossible to create a
 * useful shadow vnode.  And we need the shadow vnode for things like
 * OPEN.
 */

/* ARGSUSED */
/*
 * XXX Check nfs4_vget_pseudo() for dependency.
 */
static int
nfs4_vget(vfs_t *vfsp, vnode_t **vpp, fid_t *fidp)
{
        return (EREMOTE);
}

/*
 * nfs4_mountroot get called in the case where we are diskless booting.  All
 * we need from here is the ability to get the server info and from there we
 * can simply call nfs4_rootvp.
 */
/* ARGSUSED */
static int
nfs4_mountroot(vfs_t *vfsp, whymountroot_t why)
{
        vnode_t *rtvp;
        char root_hostname[SYS_NMLN+1];
        struct servinfo4 *svp;
        int error;
        int vfsflags;
        size_t size;
        char *root_path;
        struct pathname pn;
        char *name;
        cred_t *cr;
        mntinfo4_t *mi;
        struct nfs_args args;           /* nfs mount arguments */
        static char token[10];
        nfs4_error_t n4e;

        bzero(&args, sizeof (args));

        /* do this BEFORE getfile which causes xid stamps to be initialized */
        clkset(-1L);            /* hack for now - until we get time svc? */

        if (why == ROOT_REMOUNT) {
                /*
                 * Shouldn't happen.
                 */
                panic("nfs4_mountroot: why == ROOT_REMOUNT");
        }

        if (why == ROOT_UNMOUNT) {
                /*
                 * Nothing to do for NFS.
                 */
                return (0);
        }

        /*
         * why == ROOT_INIT
         */

        name = token;
        *name = 0;
        (void) getfsname("root", name, sizeof (token));

        pn_alloc(&pn);
        root_path = pn.pn_path;

        svp = kmem_zalloc(sizeof (*svp), KM_SLEEP);
        nfs_rw_init(&svp->sv_lock, NULL, RW_DEFAULT, NULL);
        svp->sv_knconf = kmem_zalloc(sizeof (*svp->sv_knconf), KM_SLEEP);
        svp->sv_knconf->knc_protofmly = kmem_alloc(KNC_STRSIZE, KM_SLEEP);
        svp->sv_knconf->knc_proto = kmem_alloc(KNC_STRSIZE, KM_SLEEP);

        /*
         * Get server address
         * Get the root path
         * Get server's transport
         * Get server's hostname
         * Get options
         */
        args.addr = &svp->sv_addr;
        (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
        args.fh = (char *)&svp->sv_fhandle;
        args.knconf = svp->sv_knconf;
        args.hostname = root_hostname;
        vfsflags = 0;
        if (error = mount_root(*name ? name : "root", root_path, NFS_V4,
            &args, &vfsflags)) {
                if (error == EPROTONOSUPPORT)
                        nfs_cmn_err(error, CE_WARN, "nfs4_mountroot: "
                            "mount_root failed: server doesn't support NFS V4");
                else
                        nfs_cmn_err(error, CE_WARN,
                            "nfs4_mountroot: mount_root failed: %m");
                nfs_rw_exit(&svp->sv_lock);
                sv4_free(svp);
                pn_free(&pn);
                return (error);
        }
        nfs_rw_exit(&svp->sv_lock);
        svp->sv_hostnamelen = (int)(strlen(root_hostname) + 1);
        svp->sv_hostname = kmem_alloc(svp->sv_hostnamelen, KM_SLEEP);
        (void) strcpy(svp->sv_hostname, root_hostname);

        svp->sv_pathlen = (int)(strlen(root_path) + 1);
        svp->sv_path = kmem_alloc(svp->sv_pathlen, KM_SLEEP);
        (void) strcpy(svp->sv_path, root_path);

        /*
         * Force root partition to always be mounted with AUTH_UNIX for now
         */
        svp->sv_secdata = kmem_alloc(sizeof (*svp->sv_secdata), KM_SLEEP);
        svp->sv_secdata->secmod = AUTH_UNIX;
        svp->sv_secdata->rpcflavor = AUTH_UNIX;
        svp->sv_secdata->data = NULL;

        cr = crgetcred();
        rtvp = NULL;

        error = nfs4rootvp(&rtvp, vfsp, svp, args.flags, cr, global_zone);

        if (error) {
                crfree(cr);
                pn_free(&pn);
                sv4_free(svp);
                return (error);
        }

        mi = VTOMI4(rtvp);

        /*
         * Send client id to the server, if necessary
         */
        nfs4_error_zinit(&n4e);
        nfs4setclientid(mi, cr, FALSE, &n4e);
        error = n4e.error;

        crfree(cr);

        if (error) {
                pn_free(&pn);
                goto errout;
        }

        error = nfs4_setopts(rtvp, DATAMODEL_NATIVE, &args);
        if (error) {
                nfs_cmn_err(error, CE_WARN,
                    "nfs4_mountroot: invalid root mount options");
                pn_free(&pn);
                goto errout;
        }

        (void) vfs_lock_wait(vfsp);
        vfs_add(NULL, vfsp, vfsflags);
        vfs_unlock(vfsp);

        size = strlen(svp->sv_hostname);
        (void) strcpy(rootfs.bo_name, svp->sv_hostname);
        rootfs.bo_name[size] = ':';
        (void) strcpy(&rootfs.bo_name[size + 1], root_path);

        pn_free(&pn);

errout:
        if (error) {
                sv4_free(svp);
                nfs4_async_stop(vfsp);
                nfs4_async_manager_stop(vfsp);
        }

        if (rtvp != NULL)
                VN_RELE(rtvp);

        return (error);
}

/*
 * Initialization routine for VFS routines.  Should only be called once
 */
int
nfs4_vfsinit(void)
{
        mutex_init(&nfs4_syncbusy, NULL, MUTEX_DEFAULT, NULL);
        nfs4setclientid_init();
        nfs4_ephemeral_init();
        return (0);
}

void
nfs4_vfsfini(void)
{
        nfs4_ephemeral_fini();
        nfs4setclientid_fini();
        mutex_destroy(&nfs4_syncbusy);
}

void
nfs4_freevfs(vfs_t *vfsp)
{
        mntinfo4_t *mi;

        /* need to release the initial hold */
        mi = VFTOMI4(vfsp);

        /*
         * At this point, we can no longer reference the vfs
         * and need to inform other holders of the reference
         * to the mntinfo4_t.
         */
        mi->mi_vfsp = NULL;

        MI4_RELE(mi);
}

/*
 * Client side SETCLIENTID and SETCLIENTID_CONFIRM
 */
struct nfs4_server nfs4_server_lst =
        { &nfs4_server_lst, &nfs4_server_lst };

kmutex_t nfs4_server_lst_lock;

static void
nfs4setclientid_init(void)
{
        mutex_init(&nfs4_server_lst_lock, NULL, MUTEX_DEFAULT, NULL);
}

static void
nfs4setclientid_fini(void)
{
        mutex_destroy(&nfs4_server_lst_lock);
}

int nfs4_retry_sclid_delay = NFS4_RETRY_SCLID_DELAY;
int nfs4_num_sclid_retries = NFS4_NUM_SCLID_RETRIES;

/*
 * Set the clientid for the server for "mi".  No-op if the clientid is
 * already set.
 *
 * The recovery boolean should be set to TRUE if this function was called
 * by the recovery code, and FALSE otherwise.  This is used to determine
 * if we need to call nfs4_start/end_op as well as grab the mi_recovlock
 * for adding a mntinfo4_t to a nfs4_server_t.
 *
 * Error is returned via 'n4ep'.  If there was a 'n4ep->stat' error, then
 * 'n4ep->error' is set to geterrno4(n4ep->stat).
 */
void
nfs4setclientid(mntinfo4_t *mi, cred_t *cr, bool_t recovery, nfs4_error_t *n4ep)
{
        struct nfs4_server *np;
        struct servinfo4 *svp = mi->mi_curr_serv;
        nfs4_recov_state_t recov_state;
        int num_retries = 0;
        bool_t retry;
        cred_t *lcr = NULL;
        int retry_inuse = 1; /* only retry once on NFS4ERR_CLID_INUSE */
        time_t lease_time = 0;

        recov_state.rs_flags = 0;
        recov_state.rs_num_retry_despite_err = 0;
        ASSERT(n4ep != NULL);

recov_retry:
        retry = FALSE;
        nfs4_error_zinit(n4ep);
        if (!recovery)
                (void) nfs_rw_enter_sig(&mi->mi_recovlock, RW_READER, 0);

        mutex_enter(&nfs4_server_lst_lock);
        np = servinfo4_to_nfs4_server(svp); /* This locks np if it is found */
        mutex_exit(&nfs4_server_lst_lock);
        if (!np) {
                struct nfs4_server *tnp;
                np = new_nfs4_server(svp, cr);
                mutex_enter(&np->s_lock);

                mutex_enter(&nfs4_server_lst_lock);
                tnp = servinfo4_to_nfs4_server(svp);
                if (tnp) {
                        /*
                         * another thread snuck in and put server on list.
                         * since we aren't adding it to the nfs4_server_list
                         * we need to set the ref count to 0 and destroy it.
                         */
                        np->s_refcnt = 0;
                        destroy_nfs4_server(np);
                        np = tnp;
                } else {
                        /*
                         * do not give list a reference until everything
                         * succeeds
                         */
                        insque(np, &nfs4_server_lst);
                }
                mutex_exit(&nfs4_server_lst_lock);
        }
        ASSERT(MUTEX_HELD(&np->s_lock));
        /*
         * If we find the server already has N4S_CLIENTID_SET, then
         * just return, we've already done SETCLIENTID to that server
         */
        if (np->s_flags & N4S_CLIENTID_SET) {
                /* add mi to np's mntinfo4_list */
                nfs4_add_mi_to_server(np, mi);
                if (!recovery)
                        nfs_rw_exit(&mi->mi_recovlock);
                mutex_exit(&np->s_lock);
                nfs4_server_rele(np);
                return;
        }
        mutex_exit(&np->s_lock);


        /*
         * Drop the mi_recovlock since nfs4_start_op will
         * acquire it again for us.
         */
        if (!recovery) {
                nfs_rw_exit(&mi->mi_recovlock);

                n4ep->error = nfs4_start_op(mi, NULL, NULL, &recov_state);
                if (n4ep->error) {
                        nfs4_server_rele(np);
                        return;
                }
        }

        mutex_enter(&np->s_lock);
        while (np->s_flags & N4S_CLIENTID_PEND) {
                if (!cv_wait_sig(&np->s_clientid_pend, &np->s_lock)) {
                        mutex_exit(&np->s_lock);
                        nfs4_server_rele(np);
                        if (!recovery)
                                nfs4_end_op(mi, NULL, NULL, &recov_state,
                                    recovery);
                        n4ep->error = EINTR;
                        return;
                }
        }

        if (np->s_flags & N4S_CLIENTID_SET) {
                /* XXX copied/pasted from above */
                /* add mi to np's mntinfo4_list */
                nfs4_add_mi_to_server(np, mi);
                mutex_exit(&np->s_lock);
                nfs4_server_rele(np);
                if (!recovery)
                        nfs4_end_op(mi, NULL, NULL, &recov_state, recovery);
                return;
        }

        /*
         * Reset the N4S_CB_PINGED flag. This is used to
         * indicate if we have received a CB_NULL from the
         * server. Also we reset the waiter flag.
         */
        np->s_flags &= ~(N4S_CB_PINGED | N4S_CB_WAITER);
        /* any failure must now clear this flag */
        np->s_flags |= N4S_CLIENTID_PEND;
        mutex_exit(&np->s_lock);
        nfs4setclientid_otw(mi, svp, cr, np, n4ep, &retry_inuse);

        if (n4ep->error == EACCES) {
                /*
                 * If the uid is set then set the creds for secure mounts
                 * by proxy processes such as automountd.
                 */
                (void) nfs_rw_enter_sig(&svp->sv_lock, RW_READER, 0);
                if (svp->sv_secdata->uid != 0) {
                        lcr = crdup(cr);
                        (void) crsetugid(lcr, svp->sv_secdata->uid,
                            crgetgid(cr));
                }
                nfs_rw_exit(&svp->sv_lock);

                if (lcr != NULL) {
                        mutex_enter(&np->s_lock);
                        crfree(np->s_cred);
                        np->s_cred = lcr;
                        mutex_exit(&np->s_lock);
                        nfs4setclientid_otw(mi, svp, lcr, np, n4ep,
                            &retry_inuse);
                }
        }
        mutex_enter(&np->s_lock);
        lease_time = np->s_lease_time;
        np->s_flags &= ~N4S_CLIENTID_PEND;
        mutex_exit(&np->s_lock);

        if (n4ep->error != 0 || n4ep->stat != NFS4_OK) {
                /*
                 * Start recovery if failover is a possibility.  If
                 * invoked by the recovery thread itself, then just
                 * return and let it handle the failover first.  NB:
                 * recovery is not allowed if the mount is in progress
                 * since the infrastructure is not sufficiently setup
                 * to allow it.  Just return the error (after suitable
                 * retries).
                 */
                if (FAILOVER_MOUNT4(mi) && nfs4_try_failover(n4ep)) {
                        (void) nfs4_start_recovery(n4ep, mi, NULL,
                            NULL, NULL, NULL, OP_SETCLIENTID, NULL, NULL, NULL);
                        /*
                         * Don't retry here, just return and let
                         * recovery take over.
                         */
                        if (recovery)
                                retry = FALSE;
                } else if (nfs4_rpc_retry_error(n4ep->error) ||
                    n4ep->stat == NFS4ERR_RESOURCE ||
                    n4ep->stat == NFS4ERR_STALE_CLIENTID) {

                        retry = TRUE;
                        /*
                         * Always retry if in recovery or once had
                         * contact with the server (but now it's
                         * overloaded).
                         */
                        if (recovery == TRUE ||
                            n4ep->error == ETIMEDOUT ||
                            n4ep->error == ECONNRESET)
                                num_retries = 0;
                } else if (retry_inuse && n4ep->error == 0 &&
                    n4ep->stat == NFS4ERR_CLID_INUSE) {
                        retry = TRUE;
                        num_retries = 0;
                }
        } else {
                /*
                 * Since everything succeeded give the list a reference count if
                 * it hasn't been given one by add_new_nfs4_server() or if this
                 * is not a recovery situation in which case it is already on
                 * the list.
                 */
                mutex_enter(&np->s_lock);
                if ((np->s_flags & N4S_INSERTED) == 0) {
                        np->s_refcnt++;
                        np->s_flags |= N4S_INSERTED;
                }
                mutex_exit(&np->s_lock);
        }

        if (!recovery)
                nfs4_end_op(mi, NULL, NULL, &recov_state, recovery);


        if (retry && num_retries++ < nfs4_num_sclid_retries) {
                if (retry_inuse) {
                        ddi_sleep(lease_time + nfs4_retry_sclid_delay);
                        retry_inuse = 0;
                } else
                        ddi_sleep(nfs4_retry_sclid_delay);

                nfs4_server_rele(np);
                goto recov_retry;
        }


        if (n4ep->error == 0)
                n4ep->error = geterrno4(n4ep->stat);

        /* broadcast before release in case no other threads are waiting */
        cv_broadcast(&np->s_clientid_pend);
        nfs4_server_rele(np);
}

int nfs4setclientid_otw_debug = 0;

/*
 * This function handles the recovery of STALE_CLIENTID for SETCLIENTID_CONFRIM,
 * but nothing else; the calling function must be designed to handle those
 * other errors.
 */
static void
nfs4setclientid_otw(mntinfo4_t *mi, struct servinfo4 *svp,  cred_t *cr,
    struct nfs4_server *np, nfs4_error_t *ep, int *retry_inusep)
{
        COMPOUND4args_clnt args;
        COMPOUND4res_clnt res;
        nfs_argop4 argop[3];
        SETCLIENTID4args *s_args;
        SETCLIENTID4resok *s_resok;
        int doqueue = 1;
        nfs4_ga_res_t *garp = NULL;
        timespec_t prop_time, after_time;
        verifier4 verf;
        clientid4 tmp_clientid;

        ASSERT(!MUTEX_HELD(&np->s_lock));

        args.ctag = TAG_SETCLIENTID;

        args.array = argop;
        args.array_len = 3;

        /* PUTROOTFH */
        argop[0].argop = OP_PUTROOTFH;

        /* GETATTR */
        argop[1].argop = OP_GETATTR;
        argop[1].nfs_argop4_u.opgetattr.attr_request = FATTR4_LEASE_TIME_MASK;
        argop[1].nfs_argop4_u.opgetattr.mi = mi;

        /* SETCLIENTID */
        argop[2].argop = OP_SETCLIENTID;

        s_args = &argop[2].nfs_argop4_u.opsetclientid;

        mutex_enter(&np->s_lock);

        s_args->client.verifier = np->clidtosend.verifier;
        s_args->client.id_len = np->clidtosend.id_len;
        ASSERT(s_args->client.id_len <= NFS4_OPAQUE_LIMIT);
        s_args->client.id_val = np->clidtosend.id_val;

        /*
         * Callback needs to happen on non-RDMA transport
         * Check if we have saved the original knetconfig
         * if so, use that instead.
         */
        if (svp->sv_origknconf != NULL)
                nfs4_cb_args(np, svp->sv_origknconf, s_args);
        else
                nfs4_cb_args(np, svp->sv_knconf, s_args);

        mutex_exit(&np->s_lock);

        rfs4call(mi, &args, &res, cr, &doqueue, 0, ep);

        if (ep->error)
                return;

        /* getattr lease_time res */
        if ((res.array_len >= 2) &&
            (res.array[1].nfs_resop4_u.opgetattr.status == NFS4_OK)) {
                garp = &res.array[1].nfs_resop4_u.opgetattr.ga_res;

#ifndef _LP64
                /*
                 * The 32 bit client cannot handle a lease time greater than
                 * (INT32_MAX/1000000).  This is due to the use of the
                 * lease_time in calls to drv_usectohz() in
                 * nfs4_renew_lease_thread().  The problem is that
                 * drv_usectohz() takes a time_t (which is just a long = 4
                 * bytes) as its parameter.  The lease_time is multiplied by
                 * 1000000 to convert seconds to usecs for the parameter.  If
                 * a number bigger than (INT32_MAX/1000000) is used then we
                 * overflow on the 32bit client.
                 */
                if (garp->n4g_ext_res->n4g_leasetime > (INT32_MAX/1000000)) {
                        garp->n4g_ext_res->n4g_leasetime = INT32_MAX/1000000;
                }
#endif

                mutex_enter(&np->s_lock);
                np->s_lease_time = garp->n4g_ext_res->n4g_leasetime;

                /*
                 * Keep track of the lease period for the mi's
                 * mi_msg_list.  We need an appropiate time
                 * bound to associate past facts with a current
                 * event.  The lease period is perfect for this.
                 */
                mutex_enter(&mi->mi_msg_list_lock);
                mi->mi_lease_period = np->s_lease_time;
                mutex_exit(&mi->mi_msg_list_lock);
                mutex_exit(&np->s_lock);
        }


        if (res.status == NFS4ERR_CLID_INUSE) {
                clientaddr4 *clid_inuse;

                if (!(*retry_inusep)) {
                        clid_inuse = &res.array->nfs_resop4_u.
                            opsetclientid.SETCLIENTID4res_u.client_using;

                        zcmn_err(mi->mi_zone->zone_id, CE_NOTE,
                            "NFS4 mount (SETCLIENTID failed)."
                            "  nfs4_client_id.id is in"
                            "use already by: r_netid<%s> r_addr<%s>",
                            clid_inuse->r_netid, clid_inuse->r_addr);
                }

                /*
                 * XXX - The client should be more robust in its
                 * handling of clientid in use errors (regen another
                 * clientid and try again?)
                 */
                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
                return;
        }

        if (res.status) {
                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
                return;
        }

        s_resok = &res.array[2].nfs_resop4_u.
            opsetclientid.SETCLIENTID4res_u.resok4;

        tmp_clientid = s_resok->clientid;

        verf = s_resok->setclientid_confirm;

#ifdef  DEBUG
        if (nfs4setclientid_otw_debug) {
                union {
                        clientid4       clientid;
                        int             foo[2];
                } cid;

                cid.clientid = s_resok->clientid;

                zcmn_err(mi->mi_zone->zone_id, CE_NOTE,
                "nfs4setclientid_otw: OK, clientid = %x,%x, "
                "verifier = %" PRIx64 "\n", cid.foo[0], cid.foo[1], verf);
        }
#endif

        xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);

        /* Confirm the client id and get the lease_time attribute */

        args.ctag = TAG_SETCLIENTID_CF;

        args.array = argop;
        args.array_len = 1;

        argop[0].argop = OP_SETCLIENTID_CONFIRM;

        argop[0].nfs_argop4_u.opsetclientid_confirm.clientid = tmp_clientid;
        argop[0].nfs_argop4_u.opsetclientid_confirm.setclientid_confirm = verf;

        /* used to figure out RTT for np */
        gethrestime(&prop_time);

        NFS4_DEBUG(nfs4_client_lease_debug, (CE_NOTE, "nfs4setlientid_otw: "
            "start time: %ld sec %ld nsec", prop_time.tv_sec,
            prop_time.tv_nsec));

        rfs4call(mi, &args, &res, cr, &doqueue, 0, ep);

        gethrestime(&after_time);
        mutex_enter(&np->s_lock);
        np->propagation_delay.tv_sec =
            MAX(1, after_time.tv_sec - prop_time.tv_sec);
        mutex_exit(&np->s_lock);

        NFS4_DEBUG(nfs4_client_lease_debug, (CE_NOTE, "nfs4setlcientid_otw: "
            "finish time: %ld sec ", after_time.tv_sec));

        NFS4_DEBUG(nfs4_client_lease_debug, (CE_NOTE, "nfs4setclientid_otw: "
            "propagation delay set to %ld sec",
            np->propagation_delay.tv_sec));

        if (ep->error)
                return;

        if (res.status == NFS4ERR_CLID_INUSE) {
                clientaddr4 *clid_inuse;

                if (!(*retry_inusep)) {
                        clid_inuse = &res.array->nfs_resop4_u.
                            opsetclientid.SETCLIENTID4res_u.client_using;

                        zcmn_err(mi->mi_zone->zone_id, CE_NOTE,
                            "SETCLIENTID_CONFIRM failed.  "
                            "nfs4_client_id.id is in use already by: "
                            "r_netid<%s> r_addr<%s>",
                            clid_inuse->r_netid, clid_inuse->r_addr);
                }

                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
                return;
        }

        if (res.status) {
                xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
                return;
        }

        mutex_enter(&np->s_lock);
        np->clientid = tmp_clientid;
        np->s_flags |= N4S_CLIENTID_SET;

        /* Add mi to np's mntinfo4 list */
        nfs4_add_mi_to_server(np, mi);

        if (np->lease_valid == NFS4_LEASE_NOT_STARTED) {
                /*
                 * Start lease management thread.
                 * Keep trying until we succeed.
                 */

                np->s_refcnt++;         /* pass reference to thread */
                (void) zthread_create(NULL, 0, nfs4_renew_lease_thread, np, 0,
                    minclsyspri);
        }
        mutex_exit(&np->s_lock);

        xdr_free(xdr_COMPOUND4res_clnt, (caddr_t)&res);
}

/*
 * Add mi to sp's mntinfo4_list if it isn't already in the list.  Makes
 * mi's clientid the same as sp's.
 * Assumes sp is locked down.
 */
void
nfs4_add_mi_to_server(nfs4_server_t *sp, mntinfo4_t *mi)
{
        mntinfo4_t *tmi;
        int in_list = 0;

        ASSERT(nfs_rw_lock_held(&mi->mi_recovlock, RW_READER) ||
            nfs_rw_lock_held(&mi->mi_recovlock, RW_WRITER));
        ASSERT(sp != &nfs4_server_lst);
        ASSERT(MUTEX_HELD(&sp->s_lock));

        NFS4_DEBUG(nfs4_client_lease_debug, (CE_NOTE,
            "nfs4_add_mi_to_server: add mi %p to sp %p",
            (void*)mi, (void*)sp));

        for (tmi = sp->mntinfo4_list;
            tmi != NULL;
            tmi = tmi->mi_clientid_next) {
                if (tmi == mi) {
                        NFS4_DEBUG(nfs4_client_lease_debug,
                            (CE_NOTE,
                            "nfs4_add_mi_to_server: mi in list"));
                        in_list = 1;
                }
        }

        /*
         * First put a hold on the mntinfo4's vfsp so that references via
         * mntinfo4_list will be valid.
         */
        if (!in_list)
                VFS_HOLD(mi->mi_vfsp);

        NFS4_DEBUG(nfs4_client_lease_debug, (CE_NOTE, "nfs4_add_mi_to_server: "
            "hold vfs %p for mi: %p", (void*)mi->mi_vfsp, (void*)mi));

        if (!in_list) {
                if (sp->mntinfo4_list)
                        sp->mntinfo4_list->mi_clientid_prev = mi;
                mi->mi_clientid_next = sp->mntinfo4_list;
                mi->mi_srv = sp;
                sp->mntinfo4_list = mi;
                mi->mi_srvsettime = gethrestime_sec();
                mi->mi_srvset_cnt++;
        }

        /* set mi's clientid to that of sp's for later matching */
        mi->mi_clientid = sp->clientid;

        /*
         * Update the clientid for any other mi's belonging to sp.  This
         * must be done here while we hold sp->s_lock, so that
         * find_nfs4_server() continues to work.
         */

        for (tmi = sp->mntinfo4_list;
            tmi != NULL;
            tmi = tmi->mi_clientid_next) {
                if (tmi != mi) {
                        tmi->mi_clientid = sp->clientid;
                }
        }
}

/*
 * Remove the mi from sp's mntinfo4_list and release its reference.
 * Exception: if mi still has open files, flag it for later removal (when
 * all the files are closed).
 *
 * If this is the last mntinfo4 in sp's list then tell the lease renewal
 * thread to exit.
 */
static void
nfs4_remove_mi_from_server_nolock(mntinfo4_t *mi, nfs4_server_t *sp)
{
        NFS4_DEBUG(nfs4_client_lease_debug, (CE_NOTE,
            "nfs4_remove_mi_from_server_nolock: remove mi %p from sp %p",
            (void*)mi, (void*)sp));

        ASSERT(sp != NULL);
        ASSERT(MUTEX_HELD(&sp->s_lock));
        ASSERT(mi->mi_open_files >= 0);

        /*
         * First make sure this mntinfo4 can be taken off of the list,
         * ie: it doesn't have any open files remaining.
         */
        if (mi->mi_open_files > 0) {
                NFS4_DEBUG(nfs4_client_lease_debug, (CE_NOTE,
                    "nfs4_remove_mi_from_server_nolock: don't "
                    "remove mi since it still has files open"));

                mutex_enter(&mi->mi_lock);
                mi->mi_flags |= MI4_REMOVE_ON_LAST_CLOSE;
                mutex_exit(&mi->mi_lock);
                return;
        }

        VFS_HOLD(mi->mi_vfsp);
        remove_mi(sp, mi);
        VFS_RELE(mi->mi_vfsp);

        if (sp->mntinfo4_list == NULL) {
                /* last fs unmounted, kill the thread */
                NFS4_DEBUG(nfs4_client_lease_debug, (CE_NOTE,
                    "remove_mi_from_nfs4_server_nolock: kill the thread"));
                nfs4_mark_srv_dead(sp);
        }
}

/*
 * Remove mi from sp's mntinfo4_list and release the vfs reference.
 */
static void
remove_mi(nfs4_server_t *sp, mntinfo4_t *mi)
{
        ASSERT(MUTEX_HELD(&sp->s_lock));

        /*
         * We release a reference, and the caller must still have a
         * reference.
         */
        ASSERT(mi->mi_vfsp->vfs_count >= 2);

        if (mi->mi_clientid_prev) {
                mi->mi_clientid_prev->mi_clientid_next = mi->mi_clientid_next;
        } else {
                /* This is the first mi in sp's mntinfo4_list */
                /*
                 * Make sure the first mntinfo4 in the list is the actual
                 * mntinfo4 passed in.
                 */
                ASSERT(sp->mntinfo4_list == mi);

                sp->mntinfo4_list = mi->mi_clientid_next;
        }
        if (mi->mi_clientid_next)
                mi->mi_clientid_next->mi_clientid_prev = mi->mi_clientid_prev;

        /* Now mark the mntinfo4's links as being removed */
        mi->mi_clientid_prev = mi->mi_clientid_next = NULL;
        mi->mi_srv = NULL;
        mi->mi_srvset_cnt++;

        VFS_RELE(mi->mi_vfsp);
}

/*
 * Free all the entries in sp's mntinfo4_list.
 */
static void
remove_all_mi(nfs4_server_t *sp)
{
        mntinfo4_t *mi;

        ASSERT(MUTEX_HELD(&sp->s_lock));

        while (sp->mntinfo4_list != NULL) {
                mi = sp->mntinfo4_list;
                /*
                 * Grab a reference in case there is only one left (which
                 * remove_mi() frees).
                 */
                VFS_HOLD(mi->mi_vfsp);
                remove_mi(sp, mi);
                VFS_RELE(mi->mi_vfsp);
        }
}

/*
 * Remove the mi from sp's mntinfo4_list as above, and rele the vfs.
 *
 * This version can be called with a null nfs4_server_t arg,
 * and will either find the right one and handle locking, or
 * do nothing because the mi wasn't added to an sp's mntinfo4_list.
 */
void
nfs4_remove_mi_from_server(mntinfo4_t *mi, nfs4_server_t *esp)
{
        nfs4_server_t   *sp;

        if (esp) {
                nfs4_remove_mi_from_server_nolock(mi, esp);
                return;
        }

        (void) nfs_rw_enter_sig(&mi->mi_recovlock, RW_READER, 0);
        if (sp = find_nfs4_server_all(mi, 1)) {
                nfs4_remove_mi_from_server_nolock(mi, sp);
                mutex_exit(&sp->s_lock);
                nfs4_server_rele(sp);
        }
        nfs_rw_exit(&mi->mi_recovlock);
}

/*
 * Return TRUE if the given server has any non-unmounted filesystems.
 */

bool_t
nfs4_fs_active(nfs4_server_t *sp)
{
        mntinfo4_t *mi;

        ASSERT(MUTEX_HELD(&sp->s_lock));

        for (mi = sp->mntinfo4_list; mi != NULL; mi = mi->mi_clientid_next) {
                if (!(mi->mi_vfsp->vfs_flag & VFS_UNMOUNTED))
                        return (TRUE);
        }

        return (FALSE);
}

/*
 * Mark sp as finished and notify any waiters.
 */

void
nfs4_mark_srv_dead(nfs4_server_t *sp)
{
        ASSERT(MUTEX_HELD(&sp->s_lock));

        sp->s_thread_exit = NFS4_THREAD_EXIT;
        cv_broadcast(&sp->cv_thread_exit);
}

/*
 * Create a new nfs4_server_t structure.
 * Returns new node unlocked and not in list, but with a reference count of
 * 1.
 */
struct nfs4_server *
new_nfs4_server(struct servinfo4 *svp, cred_t *cr)
{
        struct nfs4_server *np;
        timespec_t tt;
        union {
                struct {
                        uint32_t sec;
                        uint32_t subsec;
                } un_curtime;
                verifier4       un_verifier;
        } nfs4clientid_verifier;
        /*
         * We change this ID string carefully and with the Solaris
         * NFS server behaviour in mind.  "+referrals" indicates
         * a client that can handle an NFSv4 referral.
         */
        char id_val[] = "Solaris: %s, NFSv4 kernel client +referrals";
        int len;

        np = kmem_zalloc(sizeof (struct nfs4_server), KM_SLEEP);
        np->saddr.len = svp->sv_addr.len;
        np->saddr.maxlen = svp->sv_addr.maxlen;
        np->saddr.buf = kmem_alloc(svp->sv_addr.maxlen, KM_SLEEP);
        bcopy(svp->sv_addr.buf, np->saddr.buf, svp->sv_addr.len);
        np->s_refcnt = 1;

        /*
         * Build the nfs_client_id4 for this server mount.  Ensure
         * the verifier is useful and that the identification is
         * somehow based on the server's address for the case of
         * multi-homed servers.
         */
        nfs4clientid_verifier.un_verifier = 0;
        gethrestime(&tt);
        nfs4clientid_verifier.un_curtime.sec = (uint32_t)tt.tv_sec;
        nfs4clientid_verifier.un_curtime.subsec = (uint32_t)tt.tv_nsec;
        np->clidtosend.verifier = nfs4clientid_verifier.un_verifier;

        /*
         * calculate the length of the opaque identifier.  Subtract 2
         * for the "%s" and add the traditional +1 for null
         * termination.
         */
        len = strlen(id_val) - 2 + strlen(uts_nodename()) + 1;
        np->clidtosend.id_len = len + np->saddr.maxlen;

        np->clidtosend.id_val = kmem_alloc(np->clidtosend.id_len, KM_SLEEP);
        (void) sprintf(np->clidtosend.id_val, id_val, uts_nodename());
        bcopy(np->saddr.buf, &np->clidtosend.id_val[len], np->saddr.len);

        np->s_flags = 0;
        np->mntinfo4_list = NULL;
        /* save cred for issuing rfs4calls inside the renew thread */
        crhold(cr);
        np->s_cred = cr;
        cv_init(&np->cv_thread_exit, NULL, CV_DEFAULT, NULL);
        mutex_init(&np->s_lock, NULL, MUTEX_DEFAULT, NULL);
        nfs_rw_init(&np->s_recovlock, NULL, RW_DEFAULT, NULL);
        list_create(&np->s_deleg_list, sizeof (rnode4_t),
            offsetof(rnode4_t, r_deleg_link));
        np->s_thread_exit = 0;
        np->state_ref_count = 0;
        np->lease_valid = NFS4_LEASE_NOT_STARTED;
        cv_init(&np->s_cv_otw_count, NULL, CV_DEFAULT, NULL);
        cv_init(&np->s_clientid_pend, NULL, CV_DEFAULT, NULL);
        np->s_otw_call_count = 0;
        cv_init(&np->wait_cb_null, NULL, CV_DEFAULT, NULL);
        np->zoneid = getzoneid();
        np->zone_globals = nfs4_get_callback_globals();
        ASSERT(np->zone_globals != NULL);
        return (np);
}

/*
 * Create a new nfs4_server_t structure and add it to the list.
 * Returns new node locked; reference must eventually be freed.
 */
static struct nfs4_server *
add_new_nfs4_server(struct servinfo4 *svp, cred_t *cr)
{
        nfs4_server_t *sp;

        ASSERT(MUTEX_HELD(&nfs4_server_lst_lock));
        sp = new_nfs4_server(svp, cr);
        mutex_enter(&sp->s_lock);
        insque(sp, &nfs4_server_lst);
        sp->s_refcnt++;                 /* list gets a reference */
        sp->s_flags |= N4S_INSERTED;
        sp->clientid = 0;
        return (sp);
}

int nfs4_server_t_debug = 0;


#ifdef DEBUG
void
dumpnfs4slist(char *txt, mntinfo4_t *mi, clientid4 clientid, servinfo4_t *srv_p)
{
        int hash16(void *p, int len);
        nfs4_server_t *np;

        NFS4_DEBUG(nfs4_server_t_debug, (CE_NOTE,
            "dumping nfs4_server_t list in %s", txt));
        NFS4_DEBUG(nfs4_server_t_debug, (CE_CONT,
            "mi 0x%p, want clientid %llx, addr %d/%04X",
            mi, (longlong_t)clientid, srv_p->sv_addr.len,
            hash16((void *)srv_p->sv_addr.buf, srv_p->sv_addr.len)));
        for (np = nfs4_server_lst.forw; np != &nfs4_server_lst;
            np = np->forw) {
                NFS4_DEBUG(nfs4_server_t_debug, (CE_CONT,
                    "node 0x%p,    clientid %llx, addr %d/%04X, cnt %d",
                    np, (longlong_t)np->clientid, np->saddr.len,
                    hash16((void *)np->saddr.buf, np->saddr.len),
                    np->state_ref_count));
                if (np->saddr.len == srv_p->sv_addr.len &&
                    bcmp(np->saddr.buf, srv_p->sv_addr.buf,
                    np->saddr.len) == 0)
                        NFS4_DEBUG(nfs4_server_t_debug, (CE_CONT,
                            " - address matches"));
                if (np->clientid == clientid || np->clientid == 0)
                        NFS4_DEBUG(nfs4_server_t_debug, (CE_CONT,
                            " - clientid matches"));
                if (np->s_thread_exit != NFS4_THREAD_EXIT)
                        NFS4_DEBUG(nfs4_server_t_debug, (CE_CONT,
                            " - thread not exiting"));
        }
        ddi_sleep(1);
}
#endif


/*
 * Move a mntinfo4_t from one server list to another.
 * Locking of the two nfs4_server_t nodes will be done in list order.
 *
 * Returns NULL if the current nfs4_server_t for the filesystem could not
 * be found (e.g., due to forced unmount).  Otherwise returns a reference
 * to the new nfs4_server_t, which must eventually be freed.
 */
nfs4_server_t *
nfs4_move_mi(mntinfo4_t *mi, servinfo4_t *old, servinfo4_t *new)
{
        nfs4_server_t *p, *op = NULL, *np = NULL;
        int num_open;
        zoneid_t zoneid = nfs_zoneid();

        ASSERT(nfs_zone() == mi->mi_zone);

        mutex_enter(&nfs4_server_lst_lock);
#ifdef DEBUG
        if (nfs4_server_t_debug)
                dumpnfs4slist("nfs4_move_mi", mi, (clientid4)0, new);
#endif
        for (p = nfs4_server_lst.forw; p != &nfs4_server_lst; p = p->forw) {
                if (p->zoneid != zoneid)
                        continue;
                if (p->saddr.len == old->sv_addr.len &&
                    bcmp(p->saddr.buf, old->sv_addr.buf, p->saddr.len) == 0 &&
                    p->s_thread_exit != NFS4_THREAD_EXIT) {
                        op = p;
                        mutex_enter(&op->s_lock);
                        op->s_refcnt++;
                }
                if (p->saddr.len == new->sv_addr.len &&
                    bcmp(p->saddr.buf, new->sv_addr.buf, p->saddr.len) == 0 &&
                    p->s_thread_exit != NFS4_THREAD_EXIT) {
                        np = p;
                        mutex_enter(&np->s_lock);
                }
                if (op != NULL && np != NULL)
                        break;
        }
        if (op == NULL) {
                /*
                 * Filesystem has been forcibly unmounted.  Bail out.
                 */
                if (np != NULL)
                        mutex_exit(&np->s_lock);
                mutex_exit(&nfs4_server_lst_lock);
                return (NULL);
        }
        if (np != NULL) {
                np->s_refcnt++;
        } else {
#ifdef DEBUG
                NFS4_DEBUG(nfs4_client_failover_debug, (CE_NOTE,
                    "nfs4_move_mi: no target nfs4_server, will create."));
#endif
                np = add_new_nfs4_server(new, kcred);
        }
        mutex_exit(&nfs4_server_lst_lock);

        NFS4_DEBUG(nfs4_client_failover_debug, (CE_NOTE,
            "nfs4_move_mi: for mi 0x%p, "
            "old servinfo4 0x%p, new servinfo4 0x%p, "
            "old nfs4_server 0x%p, new nfs4_server 0x%p, ",
            (void*)mi, (void*)old, (void*)new,
            (void*)op, (void*)np));
        ASSERT(op != NULL && np != NULL);

        /* discard any delegations */
        nfs4_deleg_discard(mi, op);

        num_open = mi->mi_open_files;
        mi->mi_open_files = 0;
        op->state_ref_count -= num_open;
        ASSERT(op->state_ref_count >= 0);
        np->state_ref_count += num_open;
        nfs4_remove_mi_from_server_nolock(mi, op);
        mi->mi_open_files = num_open;
        NFS4_DEBUG(nfs4_client_failover_debug, (CE_NOTE,
            "nfs4_move_mi: mi_open_files %d, op->cnt %d, np->cnt %d",
            mi->mi_open_files, op->state_ref_count, np->state_ref_count));

        nfs4_add_mi_to_server(np, mi);

        mutex_exit(&op->s_lock);
        mutex_exit(&np->s_lock);
        nfs4_server_rele(op);

        return (np);
}

/*
 * Need to have the nfs4_server_lst_lock.
 * Search the nfs4_server list to find a match on this servinfo4
 * based on its address.
 *
 * Returns NULL if no match is found.  Otherwise returns a reference (which
 * must eventually be freed) to a locked nfs4_server.
 */
nfs4_server_t *
servinfo4_to_nfs4_server(servinfo4_t *srv_p)
{
        nfs4_server_t *np;
        zoneid_t zoneid = nfs_zoneid();

        ASSERT(MUTEX_HELD(&nfs4_server_lst_lock));
        for (np = nfs4_server_lst.forw; np != &nfs4_server_lst; np = np->forw) {
                if (np->zoneid == zoneid &&
                    np->saddr.len == srv_p->sv_addr.len &&
                    bcmp(np->saddr.buf, srv_p->sv_addr.buf,
                    np->saddr.len) == 0 &&
                    np->s_thread_exit != NFS4_THREAD_EXIT) {
                        mutex_enter(&np->s_lock);
                        np->s_refcnt++;
                        return (np);
                }
        }
        return (NULL);
}

/*
 * Locks the nfs4_server down if it is found and returns a reference that
 * must eventually be freed.
 */
static nfs4_server_t *
lookup_nfs4_server(nfs4_server_t *sp, int any_state)
{
        nfs4_server_t *np;

        mutex_enter(&nfs4_server_lst_lock);
        for (np = nfs4_server_lst.forw; np != &nfs4_server_lst; np = np->forw) {
                mutex_enter(&np->s_lock);
                if (np == sp && np->s_refcnt > 0 &&
                    (np->s_thread_exit != NFS4_THREAD_EXIT || any_state)) {
                        mutex_exit(&nfs4_server_lst_lock);
                        np->s_refcnt++;
                        return (np);
                }
                mutex_exit(&np->s_lock);
        }
        mutex_exit(&nfs4_server_lst_lock);

        return (NULL);
}

/*
 * The caller should be holding mi->mi_recovlock, and it should continue to
 * hold the lock until done with the returned nfs4_server_t.  Once
 * mi->mi_recovlock is released, there is no guarantee that the returned
 * mi->nfs4_server_t will continue to correspond to mi.
 */
nfs4_server_t *
find_nfs4_server(mntinfo4_t *mi)
{
        ASSERT(nfs_rw_lock_held(&mi->mi_recovlock, RW_READER) ||
            nfs_rw_lock_held(&mi->mi_recovlock, RW_WRITER));

        return (lookup_nfs4_server(mi->mi_srv, 0));
}

/*
 * Same as above, but takes an "any_state" parameter which can be
 * set to 1 if the caller wishes to find nfs4_server_t's which
 * have been marked for termination by the exit of the renew
 * thread.  This should only be used by operations which are
 * cleaning up and will not cause an OTW op.
 */
nfs4_server_t *
find_nfs4_server_all(mntinfo4_t *mi, int any_state)
{
        ASSERT(nfs_rw_lock_held(&mi->mi_recovlock, RW_READER) ||
            nfs_rw_lock_held(&mi->mi_recovlock, RW_WRITER));

        return (lookup_nfs4_server(mi->mi_srv, any_state));
}

/*
 * Lock sp, but only if it's still active (in the list and hasn't been
 * flagged as exiting) or 'any_state' is non-zero.
 * Returns TRUE if sp got locked and adds a reference to sp.
 */
bool_t
nfs4_server_vlock(nfs4_server_t *sp, int any_state)
{
        return (lookup_nfs4_server(sp, any_state) != NULL);
}

/*
 * Release the reference to sp and destroy it if that's the last one.
 */

void
nfs4_server_rele(nfs4_server_t *sp)
{
        mutex_enter(&sp->s_lock);
        ASSERT(sp->s_refcnt > 0);
        sp->s_refcnt--;
        if (sp->s_refcnt > 0) {
                mutex_exit(&sp->s_lock);
                return;
        }
        mutex_exit(&sp->s_lock);

        mutex_enter(&nfs4_server_lst_lock);
        mutex_enter(&sp->s_lock);
        if (sp->s_refcnt > 0) {
                mutex_exit(&sp->s_lock);
                mutex_exit(&nfs4_server_lst_lock);
                return;
        }
        remque(sp);
        sp->forw = sp->back = NULL;
        mutex_exit(&nfs4_server_lst_lock);
        destroy_nfs4_server(sp);
}

static void
destroy_nfs4_server(nfs4_server_t *sp)
{
        ASSERT(MUTEX_HELD(&sp->s_lock));
        ASSERT(sp->s_refcnt == 0);
        ASSERT(sp->s_otw_call_count == 0);

        remove_all_mi(sp);

        crfree(sp->s_cred);
        kmem_free(sp->saddr.buf, sp->saddr.maxlen);
        kmem_free(sp->clidtosend.id_val, sp->clidtosend.id_len);
        mutex_exit(&sp->s_lock);

        /* destroy the nfs4_server */
        nfs4callback_destroy(sp);
        list_destroy(&sp->s_deleg_list);
        mutex_destroy(&sp->s_lock);
        cv_destroy(&sp->cv_thread_exit);
        cv_destroy(&sp->s_cv_otw_count);
        cv_destroy(&sp->s_clientid_pend);
        cv_destroy(&sp->wait_cb_null);
        nfs_rw_destroy(&sp->s_recovlock);
        kmem_free(sp, sizeof (*sp));
}

/*
 * Fork off a thread to free the data structures for a mount.
 */

static void
async_free_mount(vfs_t *vfsp, int flag, cred_t *cr)
{
        freemountargs_t *args;
        args = kmem_alloc(sizeof (freemountargs_t), KM_SLEEP);
        args->fm_vfsp = vfsp;
        VFS_HOLD(vfsp);
        MI4_HOLD(VFTOMI4(vfsp));
        args->fm_flag = flag;
        args->fm_cr = cr;
        crhold(cr);
        (void) zthread_create(NULL, 0, nfs4_free_mount_thread, args, 0,
            minclsyspri);
}

static void
nfs4_free_mount_thread(freemountargs_t *args)
{
        mntinfo4_t *mi;
        nfs4_free_mount(args->fm_vfsp, args->fm_flag, args->fm_cr);
        mi = VFTOMI4(args->fm_vfsp);
        crfree(args->fm_cr);
        VFS_RELE(args->fm_vfsp);
        MI4_RELE(mi);
        kmem_free(args, sizeof (freemountargs_t));
        zthread_exit();
        /* NOTREACHED */
}

/*
 * Thread to free the data structures for a given filesystem.
 */
static void
nfs4_free_mount(vfs_t *vfsp, int flag, cred_t *cr)
{
        mntinfo4_t              *mi = VFTOMI4(vfsp);
        nfs4_server_t           *sp;
        callb_cpr_t             cpr_info;
        kmutex_t                cpr_lock;
        boolean_t               async_thread;
        int                     removed;

        bool_t                  must_unlock;
        nfs4_ephemeral_tree_t   *eph_tree;

        /*
         * We need to participate in the CPR framework if this is a kernel
         * thread.
         */
        async_thread = (curproc == nfs_zone()->zone_zsched);
        if (async_thread) {
                mutex_init(&cpr_lock, NULL, MUTEX_DEFAULT, NULL);
                CALLB_CPR_INIT(&cpr_info, &cpr_lock, callb_generic_cpr,
                    "nfsv4AsyncUnmount");
        }

        /*
         * We need to wait for all outstanding OTW calls
         * and recovery to finish before we remove the mi
         * from the nfs4_server_t, as current pending
         * calls might still need this linkage (in order
         * to find a nfs4_server_t from a mntinfo4_t).
         */
        (void) nfs_rw_enter_sig(&mi->mi_recovlock, RW_READER, FALSE);
        sp = find_nfs4_server(mi);
        nfs_rw_exit(&mi->mi_recovlock);

        if (sp) {
                while (sp->s_otw_call_count != 0) {
                        if (async_thread) {
                                mutex_enter(&cpr_lock);
                                CALLB_CPR_SAFE_BEGIN(&cpr_info);
                                mutex_exit(&cpr_lock);
                        }
                        cv_wait(&sp->s_cv_otw_count, &sp->s_lock);
                        if (async_thread) {
                                mutex_enter(&cpr_lock);
                                CALLB_CPR_SAFE_END(&cpr_info, &cpr_lock);
                                mutex_exit(&cpr_lock);
                        }
                }
                mutex_exit(&sp->s_lock);
                nfs4_server_rele(sp);
                sp = NULL;
        }

        mutex_enter(&mi->mi_lock);
        while (mi->mi_in_recovery != 0) {
                if (async_thread) {
                        mutex_enter(&cpr_lock);
                        CALLB_CPR_SAFE_BEGIN(&cpr_info);
                        mutex_exit(&cpr_lock);
                }
                cv_wait(&mi->mi_cv_in_recov, &mi->mi_lock);
                if (async_thread) {
                        mutex_enter(&cpr_lock);
                        CALLB_CPR_SAFE_END(&cpr_info, &cpr_lock);
                        mutex_exit(&cpr_lock);
                }
        }
        mutex_exit(&mi->mi_lock);

        /*
         * If we got an error, then do not nuke the
         * tree. Either the harvester is busy reclaiming
         * this node or we ran into some busy condition.
         *
         * The harvester will eventually come along and cleanup.
         * The only problem would be the root mount point.
         *
         * Since the busy node can occur for a variety
         * of reasons and can result in an entry staying
         * in df output but no longer accessible from the
         * directory tree, we are okay.
         */
        if (!nfs4_ephemeral_umount(mi, flag, cr,
            &must_unlock, &eph_tree))
                nfs4_ephemeral_umount_activate(mi, &must_unlock,
                    &eph_tree);

        /*
         * The original purge of the dnlc via 'dounmount'
         * doesn't guarantee that another dnlc entry was not
         * added while we waitied for all outstanding OTW
         * and recovery calls to finish.  So re-purge the
         * dnlc now.
         */
        (void) dnlc_purge_vfsp(vfsp, 0);

        /*
         * We need to explicitly stop the manager thread; the asyc worker
         * threads can timeout and exit on their own.
         */
        mutex_enter(&mi->mi_async_lock);
        mi->mi_max_threads = 0;
        NFS4_WAKEALL_ASYNC_WORKERS(mi->mi_async_work_cv);
        mutex_exit(&mi->mi_async_lock);
        if (mi->mi_manager_thread)
                nfs4_async_manager_stop(vfsp);

        destroy_rtable4(vfsp, cr);

        nfs4_remove_mi_from_server(mi, NULL);

        if (async_thread) {
                mutex_enter(&cpr_lock);
                CALLB_CPR_EXIT(&cpr_info);      /* drops cpr_lock */
                mutex_destroy(&cpr_lock);
        }

        removed = nfs4_mi_zonelist_remove(mi);
        if (removed)
                zone_rele_ref(&mi->mi_zone_ref, ZONE_REF_NFSV4);
}

/* Referral related sub-routines */

/* Freeup knetconfig */
static void
free_knconf_contents(struct knetconfig *k)
{
        if (k == NULL)
                return;
        if (k->knc_protofmly)
                kmem_free(k->knc_protofmly, KNC_STRSIZE);
        if (k->knc_proto)
                kmem_free(k->knc_proto, KNC_STRSIZE);
}

/*
 * This updates newpath variable with exact name component from the
 * path which gave us a NFS4ERR_MOVED error.
 * If the path is /rp/aaa/bbb and nth value is 1, aaa is returned.
 */
static char *
extract_referral_point(const char *svp, int nth)
{
        int num_slashes = 0;
        const char *p;
        char *newpath = NULL;
        int i = 0;

        newpath = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
        for (p = svp; *p; p++) {
                if (*p == '/')
                        num_slashes++;
                if (num_slashes == nth + 1) {
                        p++;
                        while (*p != '/') {
                                if (*p == '\0')
                                        break;
                                newpath[i] = *p;
                                i++;
                                p++;
                        }
                        newpath[i++] = '\0';
                        break;
                }
        }
        return (newpath);
}

/*
 * This sets up a new path in sv_path to do a lookup of the referral point.
 * If the path is /rp/aaa/bbb and the referral point is aaa,
 * this updates /rp/aaa. This path will be used to get referral
 * location.
 */
static void
setup_newsvpath(servinfo4_t *svp, int nth)
{
        int num_slashes = 0, pathlen, i = 0;
        char *newpath, *p;

        newpath = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
        for (p = svp->sv_path; *p; p++) {
                newpath[i] =  *p;
                if (*p == '/')
                        num_slashes++;
                if (num_slashes == nth + 1) {
                        newpath[i] = '\0';
                        pathlen = strlen(newpath) + 1;
                        kmem_free(svp->sv_path, svp->sv_pathlen);
                        svp->sv_path = kmem_alloc(pathlen, KM_SLEEP);
                        svp->sv_pathlen = pathlen;
                        bcopy(newpath, svp->sv_path, pathlen);
                        break;
                }
                i++;
        }
        kmem_free(newpath, MAXPATHLEN);
}