[apple/xnu.git] / bsd / ufs / ufs / ufs_quota.c

/*
 * Copyright (c) 2000 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) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * 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.
 *
 *      @(#)ufs_quota.c 8.5 (Berkeley) 5/20/95
 */

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

#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>

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

/*
 * Set up the quotas for an inode.
 *
 * 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
getinoquota(ip)
        register struct inode *ip;
{
        struct ufsmount *ump;
        struct vnode *vp = ITOV(ip);
        int error;

        ump = VFSTOUFS(vp->v_mount);
        /*
         * Set up the user quota based on file uid.
         * EINVAL means that quotas are not enabled.
         */
        if (ip->i_dquot[USRQUOTA] == NODQUOT &&
            (error =
                dqget(vp, ip->i_uid, ump, USRQUOTA, &ip->i_dquot[USRQUOTA])) &&
            error != EINVAL)
                return (error);
        /*
         * Set up the group quota based on file gid.
         * EINVAL means that quotas are not enabled.
         */
        if (ip->i_dquot[GRPQUOTA] == NODQUOT &&
            (error =
                dqget(vp, ip->i_gid, ump, GRPQUOTA, &ip->i_dquot[GRPQUOTA])) &&
            error != EINVAL)
                return (error);
        return (0);
}

/*
 * Update disk usage, and take corrective action.
 */
int
chkdq(ip, change, cred, flags)
        register struct inode *ip;
        long change;
        struct ucred *cred;
        int flags;
{
        register struct dquot *dq;
        register int i;
        int ncurblocks, error;

#if DIAGNOSTIC
        if ((flags & CHOWN) == 0)
                chkdquot(ip);
#endif
        if (change == 0)
                return (0);
        if (change < 0) {
                for (i = 0; i < MAXQUOTAS; i++) {
                        if ((dq = ip->i_dquot[i]) == NODQUOT)
                                continue;
                        while (dq->dq_flags & DQ_LOCK) {
                                dq->dq_flags |= DQ_WANT;
                                sleep((caddr_t)dq, PINOD+1);
                        }
                        ncurblocks = dq->dq_curblocks + change;
                        if (ncurblocks >= 0)
                                dq->dq_curblocks = ncurblocks;
                        else
                                dq->dq_curblocks = 0;
                        dq->dq_flags &= ~DQ_BLKS;
                        dq->dq_flags |= DQ_MOD;
                }
                return (0);
        }
        if ((flags & FORCE) == 0 && cred->cr_uid != 0) {
                for (i = 0; i < MAXQUOTAS; i++) {
                        if ((dq = ip->i_dquot[i]) == NODQUOT)
                                continue;
                        if (error = chkdqchg(ip, change, cred, i))
                                return (error);
                }
        }
        for (i = 0; i < MAXQUOTAS; i++) {
                if ((dq = ip->i_dquot[i]) == NODQUOT)
                        continue;
                while (dq->dq_flags & DQ_LOCK) {
                        dq->dq_flags |= DQ_WANT;
                        sleep((caddr_t)dq, PINOD+1);
                }
                dq->dq_curblocks += change;
                dq->dq_flags |= DQ_MOD;
        }
        return (0);
}

/*
 * Check for a valid change to a users allocation.
 * Issue an error message if appropriate.
 */
int
chkdqchg(ip, change, cred, type)
        struct inode *ip;
        long change;
        struct ucred *cred;
        int type;
{
        register struct dquot *dq = ip->i_dquot[type];
        long ncurblocks = dq->dq_curblocks + change;

        /*
         * If user would exceed their hard limit, disallow space allocation.
         */
        if (ncurblocks >= dq->dq_bhardlimit && dq->dq_bhardlimit) {
                if ((dq->dq_flags & DQ_BLKS) == 0 &&
                    ip->i_uid == cred->cr_uid) {
                        uprintf("\n%s: write failed, %s disk limit reached\n",
                            ITOV(ip)->v_mount->mnt_stat.f_mntonname,
                            quotatypes[type]);
                        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 (ncurblocks >= dq->dq_bsoftlimit && dq->dq_bsoftlimit) {
                if (dq->dq_curblocks < dq->dq_bsoftlimit) {
                        dq->dq_btime = time.tv_sec +
                            VFSTOUFS(ITOV(ip)->v_mount)->um_btime[type];
                        if (ip->i_uid == cred->cr_uid)
                                uprintf("\n%s: warning, %s %s\n",
                                    ITOV(ip)->v_mount->mnt_stat.f_mntonname,
                                    quotatypes[type], "disk quota exceeded");
                        return (0);
                }
                if (time.tv_sec > dq->dq_btime) {
                        if ((dq->dq_flags & DQ_BLKS) == 0 &&
                            ip->i_uid == cred->cr_uid) {
                                uprintf("\n%s: write failed, %s %s\n",
                                    ITOV(ip)->v_mount->mnt_stat.f_mntonname,
                                    quotatypes[type],
                                    "disk quota exceeded for too long");
                                dq->dq_flags |= DQ_BLKS;
                        }
                        return (EDQUOT);
                }
        }
        return (0);
}

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

#if DIAGNOSTIC
        if ((flags & CHOWN) == 0)
                chkdquot(ip);
#endif
        if (change == 0)
                return (0);
        if (change < 0) {
                for (i = 0; i < MAXQUOTAS; i++) {
                        if ((dq = ip->i_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);
        }
        if ((flags & FORCE) == 0 && cred->cr_uid != 0) {
                for (i = 0; i < MAXQUOTAS; i++) {
                        if ((dq = ip->i_dquot[i]) == NODQUOT)
                                continue;
                        if (error = chkiqchg(ip, change, cred, i))
                                return (error);
                }
        }
        for (i = 0; i < MAXQUOTAS; i++) {
                if ((dq = ip->i_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
chkiqchg(ip, change, cred, type)
        struct inode *ip;
        long change;
        struct ucred *cred;
        int type;
{
        register struct dquot *dq = ip->i_dquot[type];
        long ncurinodes = dq->dq_curinodes + change;

        /*
         * If user would exceed their hard limit, disallow inode allocation.
         */
        if (ncurinodes >= dq->dq_ihardlimit && dq->dq_ihardlimit) {
                if ((dq->dq_flags & DQ_INODS) == 0 &&
                    ip->i_uid == cred->cr_uid) {
                        uprintf("\n%s: write failed, %s inode limit reached\n",
                            ITOV(ip)->v_mount->mnt_stat.f_mntonname,
                            quotatypes[type]);
                        dq->dq_flags |= DQ_INODS;
                }
                return (EDQUOT);
        }
        /*
         * If user is over their soft limit for too long, disallow inode
         * 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 +
                            VFSTOUFS(ITOV(ip)->v_mount)->um_itime[type];
                        if (ip->i_uid == cred->cr_uid)
                                uprintf("\n%s: warning, %s %s\n",
                                    ITOV(ip)->v_mount->mnt_stat.f_mntonname,
                                    quotatypes[type], "inode quota exceeded");
                        return (0);
                }
                if (time.tv_sec > dq->dq_itime) {
                        if ((dq->dq_flags & DQ_INODS) == 0 &&
                            ip->i_uid == cred->cr_uid) {
                                uprintf("\n%s: write failed, %s %s\n",
                                    ITOV(ip)->v_mount->mnt_stat.f_mntonname,
                                    quotatypes[type],
                                    "inode quota exceeded for too long");
                                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
chkdquot(ip)
        register struct inode *ip;
{
        struct ufsmount *ump = VFSTOUFS(ITOV(ip)->v_mount);
        register int i;

        for (i = 0; i < MAXQUOTAS; i++) {
                if (ump->um_quotas[i] == NULLVP ||
                    (ump->um_qflags[i] & (QTF_OPENING|QTF_CLOSING)))
                        continue;
                if (ip->i_dquot[i] == NODQUOT) {
                        vprint("chkdquot: missing dquot", ITOV(ip));
                        panic("missing dquot");
                }
        }
}
#endif

/*
 * Code to process quotactl commands.
 */

/*
 * Q_QUOTAON - set up a quota file for a particular file system.
 */
int
quotaon(p, mp, type, fname)
        struct proc *p;
        struct mount *mp;
        register int type;
        caddr_t fname;
{
        struct ufsmount *ump = VFSTOUFS(mp);
        struct vnode *vp, **vpp;
        struct vnode *nextvp;
        struct dquot *dq;
        int error;
        struct nameidata nd;

        vpp = &ump->um_quotas[type];
        NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, 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)
                quotaoff(p, mp, type);
        ump->um_qflags[type] |= QTF_OPENING;
        mp->mnt_flag |= MNT_QUOTA;
        vp->v_flag |= VSYSTEM;
        *vpp = vp;
        /*
         * Save the credential of the process that turned on quotas.
         * Set up the time limits for this quota.
         */
        crhold(p->p_ucred);
        ump->um_cred[type] = p->p_ucred;
        ump->um_btime[type] = MAX_DQ_TIME;
        ump->um_itime[type] = MAX_IQ_TIME;
        if (dqget(NULLVP, 0, ump, type, &dq) == 0) {
                if (dq->dq_btime > 0)
                        ump->um_btime[type] = dq->dq_btime;
                if (dq->dq_itime > 0)
                        ump->um_itime[type] = dq->dq_itime;
                dqrele(NULLVP, dq);
        }
        /*
         * Search vnodes associated with this mount point,
         * adding references to quota file being opened.
         * NB: only need to add dquot's for inodes 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 = getinoquota(VTOI(vp))) {
                        vput(vp);
                        break;
                }
                vput(vp);
                if (vp->v_mntvnodes.le_next != nextvp || vp->v_mount != mp)
                        goto again;
        }
        ump->um_qflags[type] &= ~QTF_OPENING;
        if (error)
                quotaoff(p, mp, type);
        return (error);
}

/*
 * Q_QUOTAOFF - turn off disk quotas for a filesystem.
 */
int
quotaoff(p, mp, type)
        struct proc *p;
        struct mount *mp;
        register int type;
{
        struct vnode *vp;
        struct vnode *qvp, *nextvp;
        struct ufsmount *ump = VFSTOUFS(mp);
        struct dquot *dq;
        struct inode *ip;
        int error;
        struct ucred *cred;
        
        if ((qvp = ump->um_quotas[type]) == NULLVP)
                return (0);
        ump->um_qflags[type] |= 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;
                ip = VTOI(vp);
                dq = ip->i_dquot[type];
                ip->i_dquot[type] = NODQUOT;
                dqrele(vp, dq);
                vput(vp);
                if (vp->v_mntvnodes.le_next != nextvp || vp->v_mount != mp)
                        goto again;
        }
        dqflush(qvp);
        qvp->v_flag &= ~VSYSTEM;
        error = vn_close(qvp, FREAD|FWRITE, p->p_ucred, p);
        ump->um_quotas[type] = NULLVP;
        cred = ump->um_cred[type];
        if (cred != NOCRED) {
                ump->um_cred[type] = NOCRED;
                crfree(cred);
        }
        ump->um_qflags[type] &= ~QTF_CLOSING;
        for (type = 0; type < MAXQUOTAS; type++)
                if (ump->um_quotas[type] != NULLVP)
                        break;
        if (type == MAXQUOTAS)
                mp->mnt_flag &= ~MNT_QUOTA;
        return (error);
}

/*
 * Q_GETQUOTA - return current values in a dqblk structure.
 */
int
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, VFSTOUFS(mp), 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
setquota(mp, id, type, addr)
        struct mount *mp;
        u_long id;
        int type;
        caddr_t addr;
{
        register struct dquot *dq;
        struct dquot *ndq;
        struct ufsmount *ump = VFSTOUFS(mp);
        struct dqblk newlim;
        int error;

        if (error = copyin(addr, (caddr_t)&newlim, sizeof (struct dqblk)))
                return (error);
        if (error = dqget(NULLVP, id, ump, 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_curblocks = dq->dq_curblocks;
        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_curblocks >= newlim.dqb_bsoftlimit &&
            (dq->dq_bsoftlimit == 0 || dq->dq_curblocks < dq->dq_bsoftlimit))
                newlim.dqb_btime = time.tv_sec + ump->um_btime[type];
        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 + ump->um_itime[type];
        dq->dq_dqb = newlim;
        if (dq->dq_curblocks < 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 inode and block usage.
 */
int
setuse(mp, id, type, addr)
        struct mount *mp;
        u_long id;
        int type;
        caddr_t addr;
{
        register struct dquot *dq;
        struct ufsmount *ump = VFSTOUFS(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, ump, 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_curblocks < dq->dq_bsoftlimit &&
            usage.dqb_curblocks >= dq->dq_bsoftlimit)
                dq->dq_btime = time.tv_sec + ump->um_btime[type];
        if (dq->dq_isoftlimit && dq->dq_curinodes < dq->dq_isoftlimit &&
            usage.dqb_curinodes >= dq->dq_isoftlimit)
                dq->dq_itime = time.tv_sec + ump->um_itime[type];
        dq->dq_curblocks = usage.dqb_curblocks;
        dq->dq_curinodes = usage.dqb_curinodes;
        if (dq->dq_curblocks < 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
qsync(mp)
        struct mount *mp;
{
        struct ufsmount *ump = VFSTOUFS(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 (ump->um_quotas[i] != 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 = VTOI(vp)->i_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);
}

/*
 * Code pertaining to management of the in-core dquot data structures.
 */
#define DQHASH(dqvp, id) \
        (&dqhashtbl[((((int)(dqvp)) >> 8) + id) & dqhash])
LIST_HEAD(dqhash, dquot) *dqhashtbl;
u_long dqhash;

/*
 * Dquot free list.
 */
#define DQUOTINC        5       /* minimum free dquots desired */
TAILQ_HEAD(dqfreelist, dquot) dqfreelist;
long numdquot, desireddquot = DQUOTINC;

/*
 * Initialize the quota system.
 */
void
dqinit()
{

        dqhashtbl = hashinit(desiredvnodes, M_DQUOT, &dqhash);
        TAILQ_INIT(&dqfreelist);
}

/*
 * Obtain a dquot structure for the specified identifier and quota file
 * reading the information from the file if necessary.
 */
int
dqget(vp, id, ump, type, dqp)
        struct vnode *vp;
        u_long id;
        register struct ufsmount *ump;
        register int type;
        struct dquot **dqp;
{
        struct proc *p = current_proc();                /* XXX */
        struct dquot *dq;
        struct dqhash *dqh;
        struct vnode *dqvp;
        struct iovec aiov;
        struct uio auio;
        int error;

        dqvp = ump->um_quotas[type];
        if (dqvp == NULLVP || (ump->um_qflags[type] & QTF_CLOSING)) {
                *dqp = NODQUOT;
                return (EINVAL);
        }
        /*
         * Check the cache first.
         */
        dqh = DQHASH(dqvp, id);
        for (dq = dqh->lh_first; dq; dq = dq->dq_hash.le_next) {
                if (dq->dq_id != id ||
                    dq->dq_ump->um_quotas[dq->dq_type] != dqvp)
                        continue;
                /*
                 * Cache hit with no references.  Take
                 * the structure off the free list.
                 */
                if (dq->dq_cnt == 0)
                        TAILQ_REMOVE(&dqfreelist, dq, dq_freelist);
                DQREF(dq);
                *dqp = dq;
                return (0);
        }
        /*
         * Not in cache, allocate a new one.
         */
        if (dqfreelist.tqh_first == NODQUOT &&
            numdquot < MAXQUOTAS * desiredvnodes)
                desireddquot += DQUOTINC;
        if (numdquot < desireddquot) {
                dq = (struct dquot *)_MALLOC(sizeof *dq, M_DQUOT, M_WAITOK);
                bzero((char *)dq, sizeof *dq);
                numdquot++;
        } else {
                if ((dq = dqfreelist.tqh_first) == NULL) {
                        tablefull("dquot");
                        *dqp = NODQUOT;
                        return (EUSERS);
                }
                if (dq->dq_cnt || (dq->dq_flags & DQ_MOD))
                        panic("free dquot isn't");
                TAILQ_REMOVE(&dqfreelist, dq, dq_freelist);
                LIST_REMOVE(dq, dq_hash);
        }
        /*
         * Initialize the contents of the dquot structure.
         */
        if (vp != dqvp)
                vn_lock(dqvp, LK_EXCLUSIVE | LK_RETRY, p);
        LIST_INSERT_HEAD(dqh, dq, dq_hash);
        DQREF(dq);
        dq->dq_flags = DQ_LOCK;
        dq->dq_id = id;
        dq->dq_ump = ump;
        dq->dq_type = type;
        auio.uio_iov = &aiov;
        auio.uio_iovcnt = 1;
        aiov.iov_base = (caddr_t)&dq->dq_dqb;
        aiov.iov_len = sizeof (struct dqblk);
        auio.uio_resid = sizeof (struct dqblk);
        auio.uio_offset = (off_t)(id * sizeof (struct dqblk));
        auio.uio_segflg = UIO_SYSSPACE;
        auio.uio_rw = UIO_READ;
        auio.uio_procp = (struct proc *)0;
        error = VOP_READ(dqvp, &auio, 0, ump->um_cred[type]);

        if (auio.uio_resid == sizeof(struct dqblk) && error == 0)
                bzero((caddr_t)&dq->dq_dqb, sizeof(struct dqblk));
        if (vp != dqvp)
                VOP_UNLOCK(dqvp, 0, p);
        if (dq->dq_flags & DQ_WANT)
                wakeup((caddr_t)dq);
        dq->dq_flags = 0;
        /*
         * I/O error in reading quota file, release
         * quota structure and reflect problem to caller.
         */
        if (error) {
                LIST_REMOVE(dq, dq_hash);
                dqrele(vp, dq);
                *dqp = NODQUOT;
                return (error);
        }
        /*
         * Check for no limit to enforce.
         * Initialize time values if necessary.
         */
        if (dq->dq_isoftlimit == 0 && dq->dq_bsoftlimit == 0 &&
            dq->dq_ihardlimit == 0 && dq->dq_bhardlimit == 0)
                dq->dq_flags |= DQ_FAKE;
        if (dq->dq_id != 0) {
                if (dq->dq_btime == 0)
                        dq->dq_btime = time.tv_sec + ump->um_btime[type];
                if (dq->dq_itime == 0)
                        dq->dq_itime = time.tv_sec + ump->um_itime[type];
        }
        *dqp = dq;
        return (0);
}

/*
 * Obtain a reference to a dquot.
 */
void
dqref(dq)
        struct dquot *dq;
{

        dq->dq_cnt++;
}

/*
 * Release a reference to a dquot.
 */
void
dqrele(vp, dq)
        struct vnode *vp;
        register struct dquot *dq;
{

        if (dq == NODQUOT)
                return;
        if (dq->dq_cnt > 1) {
                dq->dq_cnt--;
                return;
        }
        if (dq->dq_flags & DQ_MOD)
                (void) dqsync(vp, dq);
        if (--dq->dq_cnt > 0)
                return;
        TAILQ_INSERT_TAIL(&dqfreelist, dq, dq_freelist);
}

/*
 * Update the disk quota in the quota file.
 */
int
dqsync(vp, dq)
        struct vnode *vp;
        struct dquot *dq;
{
        struct proc *p = current_proc();                /* XXX */
        struct vnode *dqvp;
        struct iovec aiov;
        struct uio auio;
        int error;

        if (dq == NODQUOT)
                panic("dqsync: dquot");
        if ((dq->dq_flags & DQ_MOD) == 0)
                return (0);
        if ((dqvp = dq->dq_ump->um_quotas[dq->dq_type]) == NULLVP)
                panic("dqsync: file");
        if (vp != dqvp)
                vn_lock(dqvp, LK_EXCLUSIVE | LK_RETRY, p);
        while (dq->dq_flags & DQ_LOCK) {
                dq->dq_flags |= DQ_WANT;
                sleep((caddr_t)dq, PINOD+2);
                if ((dq->dq_flags & DQ_MOD) == 0) {
                        if (vp != dqvp)
                                VOP_UNLOCK(dqvp, 0, p);
                        return (0);
                }
        }
        dq->dq_flags |= DQ_LOCK;
        auio.uio_iov = &aiov;
        auio.uio_iovcnt = 1;
        aiov.iov_base = (caddr_t)&dq->dq_dqb;
        aiov.iov_len = sizeof (struct dqblk);
        auio.uio_resid = sizeof (struct dqblk);
        auio.uio_offset = (off_t)(dq->dq_id * sizeof (struct dqblk));
        auio.uio_segflg = UIO_SYSSPACE;
        auio.uio_rw = UIO_WRITE;
        auio.uio_procp = (struct proc *)0;
        error = VOP_WRITE(dqvp, &auio, 0, dq->dq_ump->um_cred[dq->dq_type]);
        if (auio.uio_resid && error == 0)
                error = EIO;
        if (dq->dq_flags & DQ_WANT)
                wakeup((caddr_t)dq);
        dq->dq_flags &= ~(DQ_MOD|DQ_LOCK|DQ_WANT);
        if (vp != dqvp)
                VOP_UNLOCK(dqvp, 0, p);
        return (error);
}

/*
 * Flush all entries from the cache for a particular vnode.
 */
void
dqflush(vp)
        register struct vnode *vp;
{
        register struct dquot *dq, *nextdq;
        struct dqhash *dqh;

        /*
         * Move all dquot's that used to refer to this quota
         * file off their hash chains (they will eventually
         * fall off the head of the free list and be re-used).
         */
        for (dqh = &dqhashtbl[dqhash]; dqh >= dqhashtbl; dqh--) {
                for (dq = dqh->lh_first; dq; dq = nextdq) {
                        nextdq = dq->dq_hash.le_next;
                        if (dq->dq_ump->um_quotas[dq->dq_type] != vp)
                                continue;
                        if (dq->dq_cnt)
                                panic("dqflush: stray dquot");
                        LIST_REMOVE(dq, dq_hash);
                        dq->dq_ump = (struct ufsmount *)0;
                }
        }
}