[apple/xnu.git] / bsd / hfs / hfs_quota.c

/*
 * Copyright (c) 2002 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1982, 1986, 1990, 1993, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Robert Elz at The University of Melbourne.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)hfs_quota.c
 *      derived from @(#)ufs_quota.c    8.5 (Berkeley) 5/20/95
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <sys/file.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/quota.h>

#include <hfs/hfs.h>
#include <hfs/hfs_cnode.h>
#include <hfs/hfs_quota.h>
#include <hfs/hfs_mount.h>

/*
 * Quota name to error message mapping.
 */
static char *quotatypes[] = INITQFNAMES;

/*
 * Set up the quotas for a cnode.
 *
 * This routine completely defines the semantics of quotas.
 * If other criterion want to be used to establish quotas, the
 * MAXQUOTAS value in quotas.h should be increased, and the
 * additional dquots set up here.
 */
int
hfs_getinoquota(cp)
        register struct cnode *cp;
{
        struct hfsmount *hfsmp;
        struct vnode *vp;
        int error;

        vp = cp->c_vp ? cp->c_vp : cp->c_rsrc_vp;
        hfsmp = VFSTOHFS(vp->v_mount);
        /*
         * Set up the user quota based on file uid.
         * EINVAL means that quotas are not enabled.
         */
        if (cp->c_dquot[USRQUOTA] == NODQUOT &&
            (error =
                dqget(vp, cp->c_uid, &hfsmp->hfs_qfiles[USRQUOTA], USRQUOTA, &cp->c_dquot[USRQUOTA])) &&
            error != EINVAL)
                return (error);
        /*
         * Set up the group quota based on file gid.
         * EINVAL means that quotas are not enabled.
         */
        if (cp->c_dquot[GRPQUOTA] == NODQUOT &&
            (error =
                dqget(vp, cp->c_gid,  &hfsmp->hfs_qfiles[GRPQUOTA], GRPQUOTA, &cp->c_dquot[GRPQUOTA])) &&
            error != EINVAL)
                return (error);
        return (0);
}

/*
 * Update disk usage, and take corrective action.
 */
int
hfs_chkdq(cp, change, cred, flags)
        register struct cnode *cp;
        int64_t change;
        struct ucred *cred;
        int flags;
{
        register struct dquot *dq;
        register int i;
        int64_t ncurbytes;
        int error;
        struct proc *p;

#if DIAGNOSTIC
        if ((flags & CHOWN) == 0)
                hfs_chkdquot(cp);
#endif
        if (change == 0)
                return (0);
        if (change < 0) {
                for (i = 0; i < MAXQUOTAS; i++) {
                        if ((dq = cp->c_dquot[i]) == NODQUOT)
                                continue;
                        while (dq->dq_flags & DQ_LOCK) {
                                dq->dq_flags |= DQ_WANT;
                                sleep((caddr_t)dq, PINOD+1);
                        }
                        ncurbytes = dq->dq_curbytes + change;
                        if (ncurbytes >= 0)
                                dq->dq_curbytes = ncurbytes;
                        else
                                dq->dq_curbytes = 0;
                        dq->dq_flags &= ~DQ_BLKS;
                        dq->dq_flags |= DQ_MOD;
                }
                return (0);
        }
        p = current_proc();
        if (cred == NOCRED)
                cred = kernproc->p_ucred;
        if ((flags & FORCE) == 0 && ((cred->cr_uid != 0) || (p->p_flag & P_FORCEQUOTA))) {
                for (i = 0; i < MAXQUOTAS; i++) {
                        if ((dq = cp->c_dquot[i]) == NODQUOT)
                                continue;
                        if (error = hfs_chkdqchg(cp, change, cred, i))
                                return (error);
                }
        }
        for (i = 0; i < MAXQUOTAS; i++) {
                if ((dq = cp->c_dquot[i]) == NODQUOT)
                        continue;
                while (dq->dq_flags & DQ_LOCK) {
                        dq->dq_flags |= DQ_WANT;
                        sleep((caddr_t)dq, PINOD+1);
                }
                dq->dq_curbytes += change;
                dq->dq_flags |= DQ_MOD;
        }
        return (0);
}

/*
 * Check for a valid change to a users allocation.
 * Issue an error message if appropriate.
 */
int
hfs_chkdqchg(cp, change, cred, type)
        struct cnode *cp;
        int64_t change;
        struct ucred *cred;
        int type;
{
        register struct dquot *dq = cp->c_dquot[type];
        u_int64_t ncurbytes = dq->dq_curbytes + change;
        struct vnode *vp = cp->c_vp ? cp->c_vp : cp->c_rsrc_vp;

        /*
         * If user would exceed their hard limit, disallow space allocation.
         */
        if (ncurbytes >= dq->dq_bhardlimit && dq->dq_bhardlimit) {
                if ((dq->dq_flags & DQ_BLKS) == 0 &&
                    cp->c_uid == cred->cr_uid) {
#if 1   
                        printf("\n%s: write failed, %s disk limit reached\n",
                            vp->v_mount->mnt_stat.f_mntonname,
                            quotatypes[type]);
#endif
                        dq->dq_flags |= DQ_BLKS;
                }
                return (EDQUOT);
        }
        /*
         * If user is over their soft limit for too long, disallow space
         * allocation. Reset time limit as they cross their soft limit.
         */
        if (ncurbytes >= dq->dq_bsoftlimit && dq->dq_bsoftlimit) {
                if (dq->dq_curbytes < dq->dq_bsoftlimit) {
                        dq->dq_btime = time.tv_sec +
                            VFSTOHFS(vp->v_mount)->hfs_qfiles[type].qf_btime;
#if 1
                        if (cp->c_uid == cred->cr_uid)
                                printf("\n%s: warning, %s %s\n",
                                    vp->v_mount->mnt_stat.f_mntonname,
                                    quotatypes[type], "disk quota exceeded");
#endif
                        return (0);
                }
                if (time.tv_sec > dq->dq_btime) {
                        if ((dq->dq_flags & DQ_BLKS) == 0 &&
                            cp->c_uid == cred->cr_uid) {
#if 1
                                printf("\n%s: write failed, %s %s\n",
                                    vp->v_mount->mnt_stat.f_mntonname,
                                    quotatypes[type],
                                    "disk quota exceeded for too long");
#endif
                                dq->dq_flags |= DQ_BLKS;
                        }
                        return (EDQUOT);
                }
        }
        return (0);
}

/*
 * Check the inode limit, applying corrective action.
 */
int
hfs_chkiq(cp, change, cred, flags)
        register struct cnode *cp;
        long change;
        struct ucred *cred;
        int flags;
{
        register struct dquot *dq;
        register int i;
        int ncurinodes, error;
        struct proc *p;

#if DIAGNOSTIC
        if ((flags & CHOWN) == 0)
                hfs_chkdquot(cp);
#endif
        if (change == 0)
                return (0);
        if (change < 0) {
                for (i = 0; i < MAXQUOTAS; i++) {
                        if ((dq = cp->c_dquot[i]) == NODQUOT)
                                continue;
                        while (dq->dq_flags & DQ_LOCK) {
                                dq->dq_flags |= DQ_WANT;
                                sleep((caddr_t)dq, PINOD+1);
                        }
                        ncurinodes = dq->dq_curinodes + change;
                        if (ncurinodes >= 0)
                                dq->dq_curinodes = ncurinodes;
                        else
                                dq->dq_curinodes = 0;
                        dq->dq_flags &= ~DQ_INODS;
                        dq->dq_flags |= DQ_MOD;
                }
                return (0);
        }
        p = current_proc();
        if (cred == NOCRED)
                cred = kernproc->p_ucred;
        if ((flags & FORCE) == 0 && ((cred->cr_uid != 0) || (p->p_flag & P_FORCEQUOTA))) {
                for (i = 0; i < MAXQUOTAS; i++) {
                        if ((dq = cp->c_dquot[i]) == NODQUOT)
                                continue;
                        if (error = hfs_chkiqchg(cp, change, cred, i))
                                return (error);
                }
        }
        for (i = 0; i < MAXQUOTAS; i++) {
                if ((dq = cp->c_dquot[i]) == NODQUOT)
                        continue;
                while (dq->dq_flags & DQ_LOCK) {
                        dq->dq_flags |= DQ_WANT;
                        sleep((caddr_t)dq, PINOD+1);
                }
                dq->dq_curinodes += change;
                dq->dq_flags |= DQ_MOD;
        }
        return (0);
}

/*
 * Check for a valid change to a users allocation.
 * Issue an error message if appropriate.
 */
int
hfs_chkiqchg(cp, change, cred, type)
        struct cnode *cp;
        long change;
        struct ucred *cred;
        int type;
{
        register struct dquot *dq = cp->c_dquot[type];
        long ncurinodes = dq->dq_curinodes + change;
        struct vnode *vp = cp->c_vp ? cp->c_vp : cp->c_rsrc_vp;

        /*
         * If user would exceed their hard limit, disallow cnode allocation.
         */
        if (ncurinodes >= dq->dq_ihardlimit && dq->dq_ihardlimit) {
                if ((dq->dq_flags & DQ_INODS) == 0 &&
                    cp->c_uid == cred->cr_uid) {
#if 1
                        printf("\n%s: write failed, %s cnode limit reached\n",
                            vp->v_mount->mnt_stat.f_mntonname,
                            quotatypes[type]);
#endif
                        dq->dq_flags |= DQ_INODS;
                }
                return (EDQUOT);
        }
        /*
         * If user is over their soft limit for too long, disallow cnode
         * allocation. Reset time limit as they cross their soft limit.
         */
        if (ncurinodes >= dq->dq_isoftlimit && dq->dq_isoftlimit) {
                if (dq->dq_curinodes < dq->dq_isoftlimit) {
                        dq->dq_itime = time.tv_sec +
                            VFSTOHFS(vp->v_mount)->hfs_qfiles[type].qf_itime;
#if 1
                        if (cp->c_uid == cred->cr_uid)
                                printf("\n%s: warning, %s %s\n",
                                    vp->v_mount->mnt_stat.f_mntonname,
                                    quotatypes[type], "cnode quota exceeded");
#endif
                        return (0);
                }
                if (time.tv_sec > dq->dq_itime) {
                        if ((dq->dq_flags & DQ_INODS) == 0 &&
                            cp->c_uid == cred->cr_uid) {
#if 1
                                printf("\n%s: write failed, %s %s\n",
                                    vp->v_mount->mnt_stat.f_mntonname,
                                    quotatypes[type],
                                    "cnode quota exceeded for too long");
#endif
                                dq->dq_flags |= DQ_INODS;
                        }
                        return (EDQUOT);
                }
        }
        return (0);
}

#if DIAGNOSTIC
/*
 * On filesystems with quotas enabled, it is an error for a file to change
 * size and not to have a dquot structure associated with it.
 */
void
hfs_chkdquot(cp)
        register struct cnode *cp;
{
        struct vnode *vp = cp->c_vp ? cp->c_vp : cp->c_rsrc_vp;
        struct hfsmount *hfsmp = VFSTOHFS(vp->v_mount);
        register int i;

        for (i = 0; i < MAXQUOTAS; i++) {
                if (hfsmp->hfs_qfiles[i].qf_vp == NULLVP ||
                    (hfsmp->hfs_qfiles[i].qf_qflags & (QTF_OPENING|QTF_CLOSING)))
                        continue;
                if (cp->c_dquot[i] == NODQUOT) {
                        vprint("chkdquot: missing dquot", vp);
                        panic("missing dquot");
                }
        }
}
#endif

/*
 * Code to process quotactl commands.
 */

/*
 * Q_QUOTAON - set up a quota file for a particular file system.
 */
int
hfs_quotaon(p, mp, type, fname, segflg)
        struct proc *p;
        struct mount *mp;
        register int type;
        caddr_t fname;
        enum uio_seg segflg;
{
        struct hfsmount *hfsmp = VFSTOHFS(mp);
        struct vnode *vp, **vpp;
        struct vnode *nextvp;
        struct dquot *dq;
        int error;
        struct nameidata nd;

        vpp = &hfsmp->hfs_qfiles[type].qf_vp;
        NDINIT(&nd, LOOKUP, FOLLOW, segflg, fname, p);
        if (error = vn_open(&nd, FREAD|FWRITE, 0))
                return (error);
        vp = nd.ni_vp;
        VOP_UNLOCK(vp, 0, p);
        if (vp->v_type != VREG) {
                (void) vn_close(vp, FREAD|FWRITE, p->p_ucred, p);
                return (EACCES);
        }
        if (*vpp != vp)
                hfs_quotaoff(p, mp, type);
        hfsmp->hfs_qfiles[type].qf_qflags |= QTF_OPENING;
        mp->mnt_flag |= MNT_QUOTA;
        vp->v_flag |= VNOFLUSH;
        *vpp = vp;
        /*
         * Save the credential of the process that turned on quotas.
         */
        crhold(p->p_ucred);
        hfsmp->hfs_qfiles[type].qf_cred = p->p_ucred;
        /* Finish initializing the quota file */
        if (error = dqfileopen(&hfsmp->hfs_qfiles[type], type))
                goto exit;
        /*
         * Search vnodes associated with this mount point,
         * adding references to quota file being opened.
         * NB: only need to add dquot's for cnodes being modified.
         */
again:
        for (vp = mp->mnt_vnodelist.lh_first; vp != NULL; vp = nextvp) {
                nextvp = vp->v_mntvnodes.le_next;
                if (vp->v_writecount == 0)
                        continue;
                if (vget(vp, LK_EXCLUSIVE, p))
                        goto again;
                if (error = hfs_getinoquota(VTOC(vp))) {
                        vput(vp);
                        break;
                }
                vput(vp);
                if (vp->v_mntvnodes.le_next != nextvp || vp->v_mount != mp)
                        goto again;
        }
exit:
        hfsmp->hfs_qfiles[type].qf_qflags &= ~QTF_OPENING;
        if (error)
                hfs_quotaoff(p, mp, type);
        return (error);
}

/*
 * Q_QUOTAOFF - turn off disk quotas for a filesystem.
 */
int
hfs_quotaoff(p, mp, type)
        struct proc *p;
        struct mount *mp;
        register int type;
{
        struct vnode *vp;
        struct vnode *qvp, *nextvp;
        struct hfsmount *hfsmp = VFSTOHFS(mp);
        struct dquot *dq;
        struct cnode *cp;
        int error;
        struct ucred *cred;
        
        if ((qvp = hfsmp->hfs_qfiles[type].qf_vp) == NULLVP)
                return (0);
        hfsmp->hfs_qfiles[type].qf_qflags |= QTF_CLOSING;
        /*
         * Search vnodes associated with this mount point,
         * deleting any references to quota file being closed.
         */
again:
        for (vp = mp->mnt_vnodelist.lh_first; vp != NULL; vp = nextvp) {
                nextvp = vp->v_mntvnodes.le_next;
                if (vget(vp, LK_EXCLUSIVE, p))
                        goto again;
                cp = VTOC(vp);
                dq = cp->c_dquot[type];
                cp->c_dquot[type] = NODQUOT;
                dqrele(vp, dq);
                vput(vp);
                if (vp->v_mntvnodes.le_next != nextvp || vp->v_mount != mp)
                        goto again;
        }
        dqflush(qvp);
        /* Finish tearing down the quota file */
        dqfileclose(&hfsmp->hfs_qfiles[type], type);
        qvp->v_flag &= ~VNOFLUSH;
        error = vn_close(qvp, FREAD|FWRITE, p->p_ucred, p);
        hfsmp->hfs_qfiles[type].qf_vp = NULLVP;
        cred = hfsmp->hfs_qfiles[type].qf_cred;
        if (cred != NOCRED) {
                hfsmp->hfs_qfiles[type].qf_cred = NOCRED;
                crfree(cred);
        }
        hfsmp->hfs_qfiles[type].qf_qflags &= ~QTF_CLOSING;
        for (type = 0; type < MAXQUOTAS; type++)
                if (hfsmp->hfs_qfiles[type].qf_vp != NULLVP)
                        break;
        if (type == MAXQUOTAS)
                mp->mnt_flag &= ~MNT_QUOTA;
        return (error);
}

/*
 * Q_GETQUOTA - return current values in a dqblk structure.
 */
int
hfs_getquota(mp, id, type, addr)
        struct mount *mp;
        u_long id;
        int type;
        caddr_t addr;
{
        struct dquot *dq;
        int error;

        if (error = dqget(NULLVP, id, &VFSTOHFS(mp)->hfs_qfiles[type], type, &dq))
                return (error);
        error = copyout((caddr_t)&dq->dq_dqb, addr, sizeof (struct dqblk));
        dqrele(NULLVP, dq);
        return (error);
}

/*
 * Q_SETQUOTA - assign an entire dqblk structure.
 */
int
hfs_setquota(mp, id, type, addr)
        struct mount *mp;
        u_long id;
        int type;
        caddr_t addr;
{
        register struct dquot *dq;
        struct dquot *ndq;
        struct hfsmount *hfsmp = VFSTOHFS(mp);
        struct dqblk newlim;
        int error;

        if (error = copyin(addr, (caddr_t)&newlim, sizeof (struct dqblk)))
                return (error);
        if (error = dqget(NULLVP, id, &hfsmp->hfs_qfiles[type], type, &ndq))
                return (error);
        dq = ndq;
        while (dq->dq_flags & DQ_LOCK) {
                dq->dq_flags |= DQ_WANT;
                sleep((caddr_t)dq, PINOD+1);
        }
        /*
         * Copy all but the current values.
         * Reset time limit if previously had no soft limit or were
         * under it, but now have a soft limit and are over it.
         */
        newlim.dqb_curbytes = dq->dq_curbytes;
        newlim.dqb_curinodes = dq->dq_curinodes;
        if (dq->dq_id != 0) {
                newlim.dqb_btime = dq->dq_btime;
                newlim.dqb_itime = dq->dq_itime;
        }
        if (newlim.dqb_bsoftlimit &&
            dq->dq_curbytes >= newlim.dqb_bsoftlimit &&
            (dq->dq_bsoftlimit == 0 || dq->dq_curbytes < dq->dq_bsoftlimit))
                newlim.dqb_btime = time.tv_sec + hfsmp->hfs_qfiles[type].qf_btime;
        if (newlim.dqb_isoftlimit &&
            dq->dq_curinodes >= newlim.dqb_isoftlimit &&
            (dq->dq_isoftlimit == 0 || dq->dq_curinodes < dq->dq_isoftlimit))
                newlim.dqb_itime = time.tv_sec + hfsmp->hfs_qfiles[type].qf_itime;
        dq->dq_dqb = newlim;
        if (dq->dq_curbytes < dq->dq_bsoftlimit)
                dq->dq_flags &= ~DQ_BLKS;
        if (dq->dq_curinodes < dq->dq_isoftlimit)
                dq->dq_flags &= ~DQ_INODS;
        if (dq->dq_isoftlimit == 0 && dq->dq_bsoftlimit == 0 &&
            dq->dq_ihardlimit == 0 && dq->dq_bhardlimit == 0)
                dq->dq_flags |= DQ_FAKE;
        else
                dq->dq_flags &= ~DQ_FAKE;
        dq->dq_flags |= DQ_MOD;
        dqrele(NULLVP, dq);
        return (0);
}

/*
 * Q_SETUSE - set current cnode and byte usage.
 */
int
hfs_setuse(mp, id, type, addr)
        struct mount *mp;
        u_long id;
        int type;
        caddr_t addr;
{
        register struct dquot *dq;
        struct hfsmount *hfsmp = VFSTOHFS(mp);
        struct dquot *ndq;
        struct dqblk usage;
        int error;

        if (error = copyin(addr, (caddr_t)&usage, sizeof (struct dqblk)))
                return (error);
        if (error = dqget(NULLVP, id, &hfsmp->hfs_qfiles[type], type, &ndq))
                return (error);
        dq = ndq;
        while (dq->dq_flags & DQ_LOCK) {
                dq->dq_flags |= DQ_WANT;
                sleep((caddr_t)dq, PINOD+1);
        }
        /*
         * Reset time limit if have a soft limit and were
         * previously under it, but are now over it.
         */
        if (dq->dq_bsoftlimit && dq->dq_curbytes < dq->dq_bsoftlimit &&
            usage.dqb_curbytes >= dq->dq_bsoftlimit)
                dq->dq_btime = time.tv_sec + hfsmp->hfs_qfiles[type].qf_btime;
        if (dq->dq_isoftlimit && dq->dq_curinodes < dq->dq_isoftlimit &&
            usage.dqb_curinodes >= dq->dq_isoftlimit)
                dq->dq_itime = time.tv_sec + hfsmp->hfs_qfiles[type].qf_itime;
        dq->dq_curbytes = usage.dqb_curbytes;
        dq->dq_curinodes = usage.dqb_curinodes;
        if (dq->dq_curbytes < dq->dq_bsoftlimit)
                dq->dq_flags &= ~DQ_BLKS;
        if (dq->dq_curinodes < dq->dq_isoftlimit)
                dq->dq_flags &= ~DQ_INODS;
        dq->dq_flags |= DQ_MOD;
        dqrele(NULLVP, dq);
        return (0);
}

/*
 * Q_SYNC - sync quota files to disk.
 */
int
hfs_qsync(mp)
        struct mount *mp;
{
        struct hfsmount *hfsmp = VFSTOHFS(mp);
        struct proc *p = current_proc();                /* XXX */
        struct vnode *vp, *nextvp;
        struct dquot *dq;
        int i, error;

        /*
         * Check if the mount point has any quotas.
         * If not, simply return.
         */
        for (i = 0; i < MAXQUOTAS; i++)
                if (hfsmp->hfs_qfiles[i].qf_vp != NULLVP)
                        break;
        if (i == MAXQUOTAS)
                return (0);
        /*
         * Search vnodes associated with this mount point,
         * synchronizing any modified dquot structures.
         */
        simple_lock(&mntvnode_slock);
again:
        for (vp = mp->mnt_vnodelist.lh_first; vp != NULL; vp = nextvp) {
                if (vp->v_mount != mp)
                        goto again;
                nextvp = vp->v_mntvnodes.le_next;
                simple_lock(&vp->v_interlock);
                simple_unlock(&mntvnode_slock);
                error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, p);
                if (error) {
                        simple_lock(&mntvnode_slock);
                        if (error == ENOENT)
                                goto again;
                        continue;
                }
                for (i = 0; i < MAXQUOTAS; i++) {
                        dq = VTOC(vp)->c_dquot[i];
                        if (dq != NODQUOT && (dq->dq_flags & DQ_MOD))
                                dqsync(vp, dq);
                }
                vput(vp);
                simple_lock(&mntvnode_slock);
                if (vp->v_mntvnodes.le_next != nextvp)
                        goto again;
        }
        simple_unlock(&mntvnode_slock);
        return (0);
}

/*
 * Q_QUOTASTAT - get quota on/off status 
 */
int
hfs_quotastat(mp, type, addr)
        struct mount *mp;
        register int type;
        caddr_t addr;
{
        struct hfsmount *hfsmp = VFSTOHFS(mp);
        int error = 0;
        int qstat;

        if ((mp->mnt_flag & MNT_QUOTA) && (hfsmp->hfs_qfiles[type].qf_vp != NULLVP))
          qstat = 1;   /* quotas are on for this type */
        else
          qstat = 0;   /* quotas are off for this type */
        
        error = copyout ((caddr_t)&qstat, addr, sizeof(qstat));
        return (error);
}