/*
 * 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 (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 *
 *      Copyright (c) 1983,1984,1985,1986,1987,1988,1989  AT&T.
 *      All rights reserved.
 *
 * Copyright 2018 Nexenta Systems, Inc.  All rights reserved.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/thread.h>
#include <sys/t_lock.h>
#include <sys/time.h>
#include <sys/vnode.h>
#include <sys/vfs.h>
#include <sys/errno.h>
#include <sys/buf.h>
#include <sys/stat.h>
#include <sys/cred.h>
#include <sys/kmem.h>
#include <sys/debug.h>
#include <sys/vmsystm.h>
#include <sys/flock.h>
#include <sys/share.h>
#include <sys/cmn_err.h>
#include <sys/tiuser.h>
#include <sys/sysmacros.h>
#include <sys/callb.h>
#include <sys/acl.h>
#include <sys/kstat.h>
#include <sys/signal.h>
#include <sys/list.h>
#include <sys/zone.h>

#include <netsmb/smb.h>
#include <netsmb/smb_conn.h>
#include <netsmb/smb_subr.h>

#include <smbfs/smbfs.h>
#include <smbfs/smbfs_node.h>
#include <smbfs/smbfs_subr.h>

#ifdef  _KERNEL
#include <vm/hat.h>
#include <vm/as.h>
#include <vm/page.h>
#include <vm/pvn.h>
#include <vm/seg.h>
#include <vm/seg_map.h>
#include <vm/seg_vn.h>
#endif  // _KERNEL

#define ATTRCACHE_VALID(vp)     (gethrtime() < VTOSMB(vp)->r_attrtime)

static int smbfs_getattr_cache(vnode_t *, smbfattr_t *);
static void smbfattr_to_vattr(vnode_t *, smbfattr_t *, vattr_t *);
static void smbfattr_to_xvattr(smbfattr_t *, vattr_t *);
static int smbfs_getattr_otw(vnode_t *, struct smbfattr *, cred_t *);


/*
 * The following code provide zone support in order to perform an action
 * for each smbfs mount in a zone.  This is also where we would add
 * per-zone globals and kernel threads for the smbfs module (since
 * they must be terminated by the shutdown callback).
 */

struct smi_globals {
        kmutex_t        smg_lock;  /* lock protecting smg_list */
        list_t          smg_list;  /* list of SMBFS mounts in zone */
        boolean_t       smg_destructor_called;
};
typedef struct smi_globals smi_globals_t;

static zone_key_t smi_list_key;

/*
 * Attributes caching:
 *
 * Attributes are cached in the smbnode in struct vattr form.
 * There is a time associated with the cached attributes (r_attrtime)
 * which tells whether the attributes are valid. The time is initialized
 * to the difference between current time and the modify time of the vnode
 * when new attributes are cached. This allows the attributes for
 * files that have changed recently to be timed out sooner than for files
 * that have not changed for a long time. There are minimum and maximum
 * timeout values that can be set per mount point.
 */

/*
 * Helper for _validate_caches
 */
int
smbfs_waitfor_purge_complete(vnode_t *vp)
{
        smbnode_t *np;
        k_sigset_t smask;

        np = VTOSMB(vp);
        if (np->r_serial != NULL && np->r_serial != curthread) {
                mutex_enter(&np->r_statelock);
                sigintr(&smask, VTOSMI(vp)->smi_flags & SMI_INT);
                while (np->r_serial != NULL) {
                        if (!cv_wait_sig(&np->r_cv, &np->r_statelock)) {
                                sigunintr(&smask);
                                mutex_exit(&np->r_statelock);
                                return (EINTR);
                        }
                }
                sigunintr(&smask);
                mutex_exit(&np->r_statelock);
        }
        return (0);
}

/*
 * Validate caches by checking cached attributes. If the cached
 * attributes have timed out, then get new attributes from the server.
 * As a side affect, this will do cache invalidation if the attributes
 * have changed.
 *
 * If the attributes have not timed out and if there is a cache
 * invalidation being done by some other thread, then wait until that
 * thread has completed the cache invalidation.
 */
int
smbfs_validate_caches(
        struct vnode *vp,
        cred_t *cr)
{
        struct smbfattr fa;
        int error;

        if (ATTRCACHE_VALID(vp)) {
                error = smbfs_waitfor_purge_complete(vp);
                if (error)
                        return (error);
                return (0);
        }

        return (smbfs_getattr_otw(vp, &fa, cr));
}

/*
 * Purge all of the various data caches.
 *
 * Here NFS also had a flags arg to control what gets flushed.
 * We only have the page cache, so no flags arg.
 */
/* ARGSUSED */
void
smbfs_purge_caches(struct vnode *vp, cred_t *cr)
{

        /*
         * Here NFS has: Purge the DNLC for this vp,
         * Clear any readdir state bits,
         * the readlink response cache, ...
         */

        /*
         * Flush the page cache.
         */
        if (vn_has_cached_data(vp)) {
                (void) VOP_PUTPAGE(vp, (u_offset_t)0, 0, B_INVAL, cr, NULL);
        }

        /*
         * Here NFS has: Flush the readdir response cache.
         * No readdir cache in smbfs.
         */
}

/*
 * Here NFS has:
 * nfs_purge_rddir_cache()
 * nfs3_cache_post_op_attr()
 * nfs3_cache_post_op_vattr()
 * nfs3_cache_wcc_data()
 */

/*
 * Check the attribute cache to see if the new attributes match
 * those cached.  If they do, the various `data' caches are
 * considered to be good.  Otherwise, purge the cached data.
 */
static void
smbfs_cache_check(
        struct vnode *vp,
        struct smbfattr *fap,
        cred_t *cr)
{
        smbnode_t *np;
        int purge_data = 0;
        int purge_acl = 0;

        np = VTOSMB(vp);
        mutex_enter(&np->r_statelock);

        /*
         * Compare with NFS macro: CACHE_VALID
         * If the mtime or size has changed,
         * purge cached data.
         */
        if (np->r_attr.fa_mtime.tv_sec != fap->fa_mtime.tv_sec ||
            np->r_attr.fa_mtime.tv_nsec != fap->fa_mtime.tv_nsec)
                purge_data = 1;
        if (np->r_attr.fa_size != fap->fa_size)
                purge_data = 1;

        if (np->r_attr.fa_ctime.tv_sec != fap->fa_ctime.tv_sec ||
            np->r_attr.fa_ctime.tv_nsec != fap->fa_ctime.tv_nsec)
                purge_acl = 1;

        if (purge_acl) {
                np->r_sectime = gethrtime();
        }

        mutex_exit(&np->r_statelock);

        if (purge_data)
                smbfs_purge_caches(vp, cr);
}

/*
 * Set attributes cache for given vnode using SMB fattr
 * and update the attribute cache timeout.
 *
 * Based on NFS: nfs_attrcache, nfs_attrcache_va
 */
void
smbfs_attrcache_fa(vnode_t *vp, struct smbfattr *fap)
{
        smbnode_t *np;
        smbmntinfo_t *smi;
        hrtime_t delta, now;
        u_offset_t newsize;
        vtype_t  vtype, oldvt;
        mode_t mode;

        np = VTOSMB(vp);
        smi = VTOSMI(vp);

        /*
         * We allow v_type to change, so set that here
         * (and the mode, which depends on the type).
         */
        if (fap->fa_attr & SMB_FA_DIR) {
                vtype = VDIR;
                mode = smi->smi_dmode;
        } else {
                vtype = VREG;
                mode = smi->smi_fmode;
        }

        mutex_enter(&np->r_statelock);
        now = gethrtime();

        /*
         * Delta is the number of nanoseconds that we will
         * cache the attributes of the file.  It is based on
         * the number of nanoseconds since the last time that
         * we detected a change.  The assumption is that files
         * that changed recently are likely to change again.
         * There is a minimum and a maximum for regular files
         * and for directories which is enforced though.
         *
         * Using the time since last change was detected
         * eliminates direct comparison or calculation
         * using mixed client and server times.  SMBFS
         * does not make any assumptions regarding the
         * client and server clocks being synchronized.
         */
        if (fap->fa_mtime.tv_sec  != np->r_attr.fa_mtime.tv_sec ||
            fap->fa_mtime.tv_nsec != np->r_attr.fa_mtime.tv_nsec ||
            fap->fa_size          != np->r_attr.fa_size)
                np->r_mtime = now;

        if ((smi->smi_flags & SMI_NOAC) || (vp->v_flag & VNOCACHE))
                delta = 0;
        else {
                delta = now - np->r_mtime;
                if (vtype == VDIR) {
                        if (delta < smi->smi_acdirmin)
                                delta = smi->smi_acdirmin;
                        else if (delta > smi->smi_acdirmax)
                                delta = smi->smi_acdirmax;
                } else {
                        if (delta < smi->smi_acregmin)
                                delta = smi->smi_acregmin;
                        else if (delta > smi->smi_acregmax)
                                delta = smi->smi_acregmax;
                }
        }

        np->r_attrtime = now + delta;
        np->r_attr = *fap;
        np->n_mode = mode;
        oldvt = vp->v_type;
        vp->v_type = vtype;

        /*
         * Shall we update r_size? (local notion of size)
         *
         * The real criteria for updating r_size should be:
         * if the file has grown on the server, or if
         * the client has not modified the file.
         *
         * Also deal with the fact that SMB presents
         * directories as having size=0.  Doing that
         * here and leaving fa_size as returned OtW
         * avoids fixing the size lots of places.
         */
        newsize = fap->fa_size;
        if (vtype == VDIR && newsize < DEV_BSIZE)
                newsize = DEV_BSIZE;

        if (np->r_size != newsize &&
            (!vn_has_cached_data(vp) ||
            (!(np->r_flags & RDIRTY) && np->r_count == 0))) {
                /* OK to set the size. */
                np->r_size = newsize;
        }

        /*
         * Here NFS has:
         * nfs_setswaplike(vp, va);
         * np->r_flags &= ~RWRITEATTR;
         * (not needed here)
         */

        np->n_flag &= ~NATTRCHANGED;
        mutex_exit(&np->r_statelock);

        if (oldvt != vtype) {
                SMBVDEBUG("vtype change %d to %d\n", oldvt, vtype);
        }
}

/*
 * Fill in attribute from the cache.
 *
 * If valid, copy to *fap and return zero,
 * otherwise return an error.
 *
 * From NFS: nfs_getattr_cache()
 */
int
smbfs_getattr_cache(vnode_t *vp, struct smbfattr *fap)
{
        smbnode_t *np;
        int error;

        np = VTOSMB(vp);

        mutex_enter(&np->r_statelock);
        if (gethrtime() >= np->r_attrtime) {
                /* cache expired */
                error = ENOENT;
        } else {
                /* cache is valid */
                *fap = np->r_attr;
                error = 0;
        }
        mutex_exit(&np->r_statelock);

        return (error);
}

/*
 * Get attributes over-the-wire and update attributes cache
 * if no error occurred in the over-the-wire operation.
 * Return 0 if successful, otherwise error.
 * From NFS: nfs_getattr_otw
 */
static int
smbfs_getattr_otw(vnode_t *vp, struct smbfattr *fap, cred_t *cr)
{
        struct smb_cred scred;
        smbnode_t       *np = VTOSMB(vp);
        smb_share_t     *ssp = np->n_mount->smi_share;
        smb_fh_t        *fhp = NULL;
        int error;

        bzero(fap, sizeof (*fap));

        /*
         * Special case the XATTR directory here (all fake).
         * OK to leave a,c,m times zero (expected).
         */
        if (vp->v_flag & V_XATTRDIR) {
                fap->fa_attr = SMB_FA_DIR;
                fap->fa_size = DEV_BSIZE;
                return (0);
        }

        /*
         * Here NFS uses the ACL RPC (if smi_flags & SMI_ACL)
         * With SMB, getting the ACL is a significantly more
         * expensive operation, so we do that only when asked
         * for the uid/gid.  See smbfsgetattr().
         */

        /* Shared lock for (possible) n_fid use. */
        if (smbfs_rw_enter_sig(&np->r_lkserlock, RW_READER, SMBINTR(vp)))
                return (EINTR);
        smb_credinit(&scred, cr);

// Does the attr. open code path work for streams?
// Trying that, and if it doesn't work enable this.
#if 0   // XXX
        /*
         * Extended attribute files
         */
        if (np->n_flag & N_XATTR) {
                error = smbfs_xa_getfattr(np, fap, scrp);
                goto out;
        }
#endif  // XXX

        if (np->n_fidrefs > 0 &&
            (fhp = np->n_fid) != NULL &&
            (fhp->fh_vcgenid == ssp->ss_vcgenid)) {
                /* Use the FID we have. */
                error = smbfs_smb_getfattr(np, fhp, fap, &scred);

        } else {
                /* This will do an attr open */
                error = smbfs_smb_getpattr(np, fap, &scred);
        }

        smb_credrele(&scred);
        smbfs_rw_exit(&np->r_lkserlock);

        if (error) {
                /* Here NFS has: PURGE_STALE_FH(error, vp, cr) */
                smbfs_attrcache_remove(np);
                if (error == ENOENT || error == ENOTDIR) {
                        /*
                         * Getattr failed because the object was
                         * removed or renamed by another client.
                         * Remove any cached attributes under it.
                         */
                        smbfs_attrcache_prune(np);
                }
                return (error);
        }

        /*
         * Here NFS has: nfs_cache_fattr(vap, fa, vap, t, cr);
         * which did: fattr_to_vattr, nfs_attr_cache.
         * We cache the fattr form, so just do the
         * cache check and store the attributes.
         */
        smbfs_cache_check(vp, fap, cr);
        smbfs_attrcache_fa(vp, fap);

        return (0);
}

/*
 * Return either cached or remote attributes. If we get remote attrs,
 * use them to check and invalidate caches, then cache the new attributes.
 *
 * From NFS: nfsgetattr()
 */
int
smbfsgetattr(vnode_t *vp, struct vattr *vap, cred_t *cr)
{
        struct smbfattr fa;
        smbmntinfo_t *smi;
        uint_t mask;
        int error;

        smi = VTOSMI(vp);

        ASSERT(curproc->p_zone == smi->smi_zone_ref.zref_zone);

        /*
         * If asked for UID or GID, update n_uid, n_gid.
         */
        mask = AT_ALL;
        if (vap->va_mask & (AT_UID | AT_GID)) {
                if (smi->smi_flags & SMI_ACL)
                        (void) smbfs_acl_getids(vp, cr);
                /* else leave as set in make_smbnode */
        } else {
                mask &= ~(AT_UID | AT_GID);
        }

        /*
         * If we've got cached attributes, just use them;
         * otherwise go to the server to get attributes,
         * which will update the cache in the process.
         */
        error = smbfs_getattr_cache(vp, &fa);
        if (error)
                error = smbfs_getattr_otw(vp, &fa, cr);
        if (error)
                return (error);
        vap->va_mask |= mask;

        /*
         * Re. client's view of the file size, see:
         * smbfs_attrcache_fa, smbfs_getattr_otw
         */
        smbfattr_to_vattr(vp, &fa, vap);
        if (vap->va_mask & AT_XVATTR)
                smbfattr_to_xvattr(&fa, vap);

        return (0);
}


/*
 * Convert SMB over the wire attributes to vnode form.
 * Returns 0 for success, error if failed (overflow, etc).
 * From NFS: nattr_to_vattr()
 */
void
smbfattr_to_vattr(vnode_t *vp, struct smbfattr *fa, struct vattr *vap)
{
        struct smbnode *np = VTOSMB(vp);

        /*
         * Take type, mode, uid, gid from the smbfs node,
         * which has have been updated by _getattr_otw.
         */
        vap->va_type = vp->v_type;
        vap->va_mode = np->n_mode;

        vap->va_uid = np->n_uid;
        vap->va_gid = np->n_gid;

        vap->va_fsid = vp->v_vfsp->vfs_dev;
        vap->va_nodeid = np->n_ino;
        vap->va_nlink = 1;

        /*
         * Difference from NFS here:  We cache attributes as
         * reported by the server, so r_attr.fa_size is the
         * server's idea of the file size.  This is called
         * for getattr, so we want to return the client's
         * idea of the file size.  NFS deals with that in
         * nfsgetattr(), the equivalent of our caller.
         */
        vap->va_size = np->r_size;

        /*
         * Times.  Note, already converted from NT to
         * Unix form (in the unmarshalling code).
         */
        vap->va_atime = fa->fa_atime;
        vap->va_mtime = fa->fa_mtime;
        vap->va_ctime = fa->fa_ctime;

        /*
         * rdev, blksize, seq are made up.
         * va_nblocks is 512 byte blocks.
         */
        vap->va_rdev = vp->v_rdev;
        vap->va_blksize = MAXBSIZE;
        vap->va_nblocks = (fsblkcnt64_t)btod(np->r_attr.fa_allocsz);
        vap->va_seq = 0;
}

/*
 * smbfattr_to_xvattr: like smbfattr_to_vattr but for
 * Extensible system attributes (PSARC 2007/315)
 */
static void
smbfattr_to_xvattr(struct smbfattr *fa, struct vattr *vap)
{
        xvattr_t *xvap = (xvattr_t *)vap;       /* *vap may be xvattr_t */
        xoptattr_t *xoap = NULL;

        if ((xoap = xva_getxoptattr(xvap)) == NULL)
                return;

        if (XVA_ISSET_REQ(xvap, XAT_CREATETIME)) {
                xoap->xoa_createtime = fa->fa_createtime;
                XVA_SET_RTN(xvap, XAT_CREATETIME);
        }

        if (XVA_ISSET_REQ(xvap, XAT_ARCHIVE)) {
                xoap->xoa_archive =
                    ((fa->fa_attr & SMB_FA_ARCHIVE) != 0);
                XVA_SET_RTN(xvap, XAT_ARCHIVE);
        }

        if (XVA_ISSET_REQ(xvap, XAT_SYSTEM)) {
                xoap->xoa_system =
                    ((fa->fa_attr & SMB_FA_SYSTEM) != 0);
                XVA_SET_RTN(xvap, XAT_SYSTEM);
        }

        if (XVA_ISSET_REQ(xvap, XAT_READONLY)) {
                xoap->xoa_readonly =
                    ((fa->fa_attr & SMB_FA_RDONLY) != 0);
                XVA_SET_RTN(xvap, XAT_READONLY);
        }

        if (XVA_ISSET_REQ(xvap, XAT_HIDDEN)) {
                xoap->xoa_hidden =
                    ((fa->fa_attr & SMB_FA_HIDDEN) != 0);
                XVA_SET_RTN(xvap, XAT_HIDDEN);
        }
}

/*
 * Here NFS has:
 *      nfs_async_... stuff
 * which we're not using (no async I/O), and:
 *      writerp(),
 *      nfs_putpages()
 *      nfs_invalidate_pages()
 * which we have in smbfs_vnops.c, and
 *      nfs_printfhandle()
 *      nfs_write_error()
 * not needed here.
 */

/*
 * Helper function for smbfs_sync
 *
 * Walk the per-zone list of smbfs mounts, calling smbfs_rflush
 * on each one.  This is a little tricky because we need to exit
 * the list mutex before each _rflush call and then try to resume
 * where we were in the list after re-entering the mutex.
 */
void
smbfs_flushall(cred_t *cr)
{
        smi_globals_t *smg;
        smbmntinfo_t *tmp_smi, *cur_smi, *next_smi;

        smg = zone_getspecific(smi_list_key, crgetzone(cr));
        ASSERT(smg != NULL);

        mutex_enter(&smg->smg_lock);
        cur_smi = list_head(&smg->smg_list);
        if (cur_smi == NULL) {
                mutex_exit(&smg->smg_lock);
                return;
        }
        VFS_HOLD(cur_smi->smi_vfsp);
        mutex_exit(&smg->smg_lock);

flush:
        smbfs_rflush(cur_smi->smi_vfsp, cr);

        mutex_enter(&smg->smg_lock);
        /*
         * Resume after cur_smi if that's still on the list,
         * otherwise restart at the head.
         */
        for (tmp_smi = list_head(&smg->smg_list);
            tmp_smi != NULL;
            tmp_smi = list_next(&smg->smg_list, tmp_smi))
                if (tmp_smi == cur_smi)
                        break;
        if (tmp_smi != NULL)
                next_smi = list_next(&smg->smg_list, tmp_smi);
        else
                next_smi = list_head(&smg->smg_list);

        if (next_smi != NULL)
                VFS_HOLD(next_smi->smi_vfsp);
        VFS_RELE(cur_smi->smi_vfsp);

        mutex_exit(&smg->smg_lock);

        if (next_smi != NULL) {
                cur_smi = next_smi;
                goto flush;
        }
}

/*
 * SMB Client initialization and cleanup.
 * Much of it is per-zone now.
 */


/* ARGSUSED */
static void *
smbfs_zone_init(zoneid_t zoneid)
{
        smi_globals_t *smg;

        smg = kmem_alloc(sizeof (*smg), KM_SLEEP);
        mutex_init(&smg->smg_lock, NULL, MUTEX_DEFAULT, NULL);
        list_create(&smg->smg_list, sizeof (smbmntinfo_t),
            offsetof(smbmntinfo_t, smi_zone_node));
        smg->smg_destructor_called = B_FALSE;
        return (smg);
}

/*
 * Callback routine to tell all SMBFS mounts in the zone to stop creating new
 * threads.  Existing threads should exit.
 */
/* ARGSUSED */
static void
smbfs_zone_shutdown(zoneid_t zoneid, void *data)
{
        smi_globals_t *smg = data;
        smbmntinfo_t *smi;

        ASSERT(smg != NULL);
again:
        mutex_enter(&smg->smg_lock);
        for (smi = list_head(&smg->smg_list); smi != NULL;
            smi = list_next(&smg->smg_list, smi)) {

                /*
                 * If we've done the shutdown work for this FS, skip.
                 * Once we go off the end of the list, we're done.
                 */
                if (smi->smi_flags & SMI_DEAD)
                        continue;

                /*
                 * We will do work, so not done.  Get a hold on the FS.
                 */
                VFS_HOLD(smi->smi_vfsp);

                mutex_enter(&smi->smi_lock);
                smi->smi_flags |= SMI_DEAD;
                mutex_exit(&smi->smi_lock);

                /*
                 * Drop lock and release FS, which may change list, then repeat.
                 * We're done when every mi has been done or the list is empty.
                 */
                mutex_exit(&smg->smg_lock);
                VFS_RELE(smi->smi_vfsp);
                goto again;
        }
        mutex_exit(&smg->smg_lock);
}

static void
smbfs_zone_free_globals(smi_globals_t *smg)
{
        list_destroy(&smg->smg_list);   /* makes sure the list is empty */
        mutex_destroy(&smg->smg_lock);
        kmem_free(smg, sizeof (*smg));

}

/* ARGSUSED */
static void
smbfs_zone_destroy(zoneid_t zoneid, void *data)
{
        smi_globals_t *smg = data;

        ASSERT(smg != NULL);
        mutex_enter(&smg->smg_lock);
        if (list_head(&smg->smg_list) != NULL) {
                /* Still waiting for VFS_FREEVFS() */
                smg->smg_destructor_called = B_TRUE;
                mutex_exit(&smg->smg_lock);
                return;
        }
        smbfs_zone_free_globals(smg);
}

/*
 * Add an SMBFS mount to the per-zone list of SMBFS mounts.
 */
void
smbfs_zonelist_add(smbmntinfo_t *smi)
{
        smi_globals_t *smg;

        smg = zone_getspecific(smi_list_key, smi->smi_zone_ref.zref_zone);
        mutex_enter(&smg->smg_lock);
        list_insert_head(&smg->smg_list, smi);
        mutex_exit(&smg->smg_lock);
}

/*
 * Remove an SMBFS mount from the per-zone list of SMBFS mounts.
 */
void
smbfs_zonelist_remove(smbmntinfo_t *smi)
{
        smi_globals_t *smg;

        smg = zone_getspecific(smi_list_key, smi->smi_zone_ref.zref_zone);
        mutex_enter(&smg->smg_lock);
        list_remove(&smg->smg_list, smi);
        /*
         * We can be called asynchronously by VFS_FREEVFS() after the zone
         * shutdown/destroy callbacks have executed; if so, clean up the zone's
         * smi_globals.
         */
        if (list_head(&smg->smg_list) == NULL &&
            smg->smg_destructor_called == B_TRUE) {
                smbfs_zone_free_globals(smg);
                return;
        }
        mutex_exit(&smg->smg_lock);
}

#ifdef  lint
#define NEED_SMBFS_CALLBACKS    1
#endif

#ifdef NEED_SMBFS_CALLBACKS
/*
 * Call-back hooks for netsmb, in case we want them.
 * Apple's VFS wants them.  We may not need them.
 */
/*ARGSUSED*/
static void smbfs_dead(smb_share_t *ssp)
{
        /*
         * Walk the mount list, finding all mounts
         * using this share...
         */
}

/*ARGSUSED*/
static void smbfs_cb_nop(smb_share_t *ss)
{
        /* no-op */
}

smb_fscb_t smbfs_cb = {
        .fscb_disconn   = smbfs_dead,
        .fscb_connect   = smbfs_cb_nop
};

#endif /* NEED_SMBFS_CALLBACKS */

/*
 * SMBFS Client initialization routine.  This routine should only be called
 * once.  It performs the following tasks:
 *      - Initalize all global locks
 *      - Call sub-initialization routines (localize access to variables)
 */
int
smbfs_clntinit(void)
{

        zone_key_create(&smi_list_key, smbfs_zone_init, smbfs_zone_shutdown,
            smbfs_zone_destroy);
#ifdef NEED_SMBFS_CALLBACKS
        (void) smb_fscb_set(&smbfs_cb);
#endif /* NEED_SMBFS_CALLBACKS */
        return (0);
}

/*
 * This routine is called when the modunload is called. This will cleanup
 * the previously allocated/initialized nodes.
 */
void
smbfs_clntfini(void)
{
#ifdef NEED_SMBFS_CALLBACKS
        (void) smb_fscb_set(NULL);
#endif /* NEED_SMBFS_CALLBACKS */
        (void) zone_key_delete(smi_list_key);
}