bridge: fix a possible use after free

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / xfs / xfs_qm_syscalls.c

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/capability.h>

#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_alloc.h"
#include "xfs_quota.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_inode.h"
#include "xfs_itable.h"
#include "xfs_bmap.h"
#include "xfs_rtalloc.h"
#include "xfs_error.h"
#include "xfs_attr.h"
#include "xfs_buf_item.h"
#include "xfs_utils.h"
#include "xfs_qm.h"
#include "xfs_trace.h"

STATIC int      xfs_qm_log_quotaoff(xfs_mount_t *, xfs_qoff_logitem_t **, uint);
STATIC int      xfs_qm_log_quotaoff_end(xfs_mount_t *, xfs_qoff_logitem_t *,
                                        uint);
STATIC uint     xfs_qm_export_flags(uint);
STATIC uint     xfs_qm_export_qtype_flags(uint);
STATIC void     xfs_qm_export_dquot(xfs_mount_t *, xfs_disk_dquot_t *,
                                        fs_disk_quota_t *);


/*
 * Turn off quota accounting and/or enforcement for all udquots and/or
 * gdquots. Called only at unmount time.
 *
 * This assumes that there are no dquots of this file system cached
 * incore, and modifies the ondisk dquot directly. Therefore, for example,
 * it is an error to call this twice, without purging the cache.
 */
int
xfs_qm_scall_quotaoff(
        xfs_mount_t             *mp,
        uint                    flags)
{
        struct xfs_quotainfo    *q = mp->m_quotainfo;
        uint                    dqtype;
        int                     error;
        uint                    inactivate_flags;
        xfs_qoff_logitem_t      *qoffstart;
        int                     nculprits;

        /*
         * No file system can have quotas enabled on disk but not in core.
         * Note that quota utilities (like quotaoff) _expect_
         * errno == EEXIST here.
         */
        if ((mp->m_qflags & flags) == 0)
                return XFS_ERROR(EEXIST);
        error = 0;

        flags &= (XFS_ALL_QUOTA_ACCT | XFS_ALL_QUOTA_ENFD);

        /*
         * We don't want to deal with two quotaoffs messing up each other,
         * so we're going to serialize it. quotaoff isn't exactly a performance
         * critical thing.
         * If quotaoff, then we must be dealing with the root filesystem.
         */
        ASSERT(q);
        mutex_lock(&q->qi_quotaofflock);

        /*
         * If we're just turning off quota enforcement, change mp and go.
         */
        if ((flags & XFS_ALL_QUOTA_ACCT) == 0) {
                mp->m_qflags &= ~(flags);

                spin_lock(&mp->m_sb_lock);
                mp->m_sb.sb_qflags = mp->m_qflags;
                spin_unlock(&mp->m_sb_lock);
                mutex_unlock(&q->qi_quotaofflock);

                /* XXX what to do if error ? Revert back to old vals incore ? */
                error = xfs_qm_write_sb_changes(mp, XFS_SB_QFLAGS);
                return (error);
        }

        dqtype = 0;
        inactivate_flags = 0;
        /*
         * If accounting is off, we must turn enforcement off, clear the
         * quota 'CHKD' certificate to make it known that we have to
         * do a quotacheck the next time this quota is turned on.
         */
        if (flags & XFS_UQUOTA_ACCT) {
                dqtype |= XFS_QMOPT_UQUOTA;
                flags |= (XFS_UQUOTA_CHKD | XFS_UQUOTA_ENFD);
                inactivate_flags |= XFS_UQUOTA_ACTIVE;
        }
        if (flags & XFS_GQUOTA_ACCT) {
                dqtype |= XFS_QMOPT_GQUOTA;
                flags |= (XFS_OQUOTA_CHKD | XFS_OQUOTA_ENFD);
                inactivate_flags |= XFS_GQUOTA_ACTIVE;
        } else if (flags & XFS_PQUOTA_ACCT) {
                dqtype |= XFS_QMOPT_PQUOTA;
                flags |= (XFS_OQUOTA_CHKD | XFS_OQUOTA_ENFD);
                inactivate_flags |= XFS_PQUOTA_ACTIVE;
        }

        /*
         * Nothing to do?  Don't complain. This happens when we're just
         * turning off quota enforcement.
         */
        if ((mp->m_qflags & flags) == 0)
                goto out_unlock;

        /*
         * Write the LI_QUOTAOFF log record, and do SB changes atomically,
         * and synchronously. If we fail to write, we should abort the
         * operation as it cannot be recovered safely if we crash.
         */
        error = xfs_qm_log_quotaoff(mp, &qoffstart, flags);
        if (error)
                goto out_unlock;

        /*
         * Next we clear the XFS_MOUNT_*DQ_ACTIVE bit(s) in the mount struct
         * to take care of the race between dqget and quotaoff. We don't take
         * any special locks to reset these bits. All processes need to check
         * these bits *after* taking inode lock(s) to see if the particular
         * quota type is in the process of being turned off. If *ACTIVE, it is
         * guaranteed that all dquot structures and all quotainode ptrs will all
         * stay valid as long as that inode is kept locked.
         *
         * There is no turning back after this.
         */
        mp->m_qflags &= ~inactivate_flags;

        /*
         * Give back all the dquot reference(s) held by inodes.
         * Here we go thru every single incore inode in this file system, and
         * do a dqrele on the i_udquot/i_gdquot that it may have.
         * Essentially, as long as somebody has an inode locked, this guarantees
         * that quotas will not be turned off. This is handy because in a
         * transaction once we lock the inode(s) and check for quotaon, we can
         * depend on the quota inodes (and other things) being valid as long as
         * we keep the lock(s).
         */
        xfs_qm_dqrele_all_inodes(mp, flags);

        /*
         * Next we make the changes in the quota flag in the mount struct.
         * This isn't protected by a particular lock directly, because we
         * don't want to take a mrlock every time we depend on quotas being on.
         */
        mp->m_qflags &= ~(flags);

        /*
         * Go through all the dquots of this file system and purge them,
         * according to what was turned off. We may not be able to get rid
         * of all dquots, because dquots can have temporary references that
         * are not attached to inodes. eg. xfs_setattr, xfs_create.
         * So, if we couldn't purge all the dquots from the filesystem,
         * we can't get rid of the incore data structures.
         */
        while ((nculprits = xfs_qm_dqpurge_all(mp, dqtype)))
                delay(10 * nculprits);

        /*
         * Transactions that had started before ACTIVE state bit was cleared
         * could have logged many dquots, so they'd have higher LSNs than
         * the first QUOTAOFF log record does. If we happen to crash when
         * the tail of the log has gone past the QUOTAOFF record, but
         * before the last dquot modification, those dquots __will__
         * recover, and that's not good.
         *
         * So, we have QUOTAOFF start and end logitems; the start
         * logitem won't get overwritten until the end logitem appears...
         */
        error = xfs_qm_log_quotaoff_end(mp, qoffstart, flags);
        if (error) {
                /* We're screwed now. Shutdown is the only option. */
                xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
                goto out_unlock;
        }

        /*
         * If quotas is completely disabled, close shop.
         */
        if (((flags & XFS_MOUNT_QUOTA_ALL) == XFS_MOUNT_QUOTA_SET1) ||
            ((flags & XFS_MOUNT_QUOTA_ALL) == XFS_MOUNT_QUOTA_SET2)) {
                mutex_unlock(&q->qi_quotaofflock);
                xfs_qm_destroy_quotainfo(mp);
                return (0);
        }

        /*
         * Release our quotainode references if we don't need them anymore.
         */
        if ((dqtype & XFS_QMOPT_UQUOTA) && q->qi_uquotaip) {
                IRELE(q->qi_uquotaip);
                q->qi_uquotaip = NULL;
        }
        if ((dqtype & (XFS_QMOPT_GQUOTA|XFS_QMOPT_PQUOTA)) && q->qi_gquotaip) {
                IRELE(q->qi_gquotaip);
                q->qi_gquotaip = NULL;
        }

out_unlock:
        mutex_unlock(&q->qi_quotaofflock);
        return error;
}

STATIC int
xfs_qm_scall_trunc_qfile(
        struct xfs_mount        *mp,
        xfs_ino_t               ino)
{
        struct xfs_inode        *ip;
        struct xfs_trans        *tp;
        int                     error;

        if (ino == NULLFSINO)
                return 0;

        error = xfs_iget(mp, NULL, ino, 0, 0, &ip);
        if (error)
                return error;

        xfs_ilock(ip, XFS_IOLOCK_EXCL);

        tp = xfs_trans_alloc(mp, XFS_TRANS_TRUNCATE_FILE);
        error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
                                  XFS_TRANS_PERM_LOG_RES,
                                  XFS_ITRUNCATE_LOG_COUNT);
        if (error) {
                xfs_trans_cancel(tp, 0);
                xfs_iunlock(ip, XFS_IOLOCK_EXCL);
                goto out_put;
        }

        xfs_ilock(ip, XFS_ILOCK_EXCL);
        xfs_trans_ijoin(tp, ip);

        error = xfs_itruncate_data(&tp, ip, 0);
        if (error) {
                xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES |
                                     XFS_TRANS_ABORT);
                goto out_unlock;
        }

        xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
        error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);

out_unlock:
        xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
out_put:
        IRELE(ip);
        return error;
}

int
xfs_qm_scall_trunc_qfiles(
        xfs_mount_t     *mp,
        uint            flags)
{
        int             error = 0, error2 = 0;

        if (!xfs_sb_version_hasquota(&mp->m_sb) || flags == 0) {
                xfs_debug(mp, "%s: flags=%x m_qflags=%x\n",
                        __func__, flags, mp->m_qflags);
                return XFS_ERROR(EINVAL);
        }

        if (flags & XFS_DQ_USER)
                error = xfs_qm_scall_trunc_qfile(mp, mp->m_sb.sb_uquotino);
        if (flags & (XFS_DQ_GROUP|XFS_DQ_PROJ))
                error2 = xfs_qm_scall_trunc_qfile(mp, mp->m_sb.sb_gquotino);

        return error ? error : error2;
}

/*
 * Switch on (a given) quota enforcement for a filesystem.  This takes
 * effect immediately.
 * (Switching on quota accounting must be done at mount time.)
 */
int
xfs_qm_scall_quotaon(
        xfs_mount_t     *mp,
        uint            flags)
{
        int             error;
        uint            qf;
        __int64_t       sbflags;

        flags &= (XFS_ALL_QUOTA_ACCT | XFS_ALL_QUOTA_ENFD);
        /*
         * Switching on quota accounting must be done at mount time.
         */
        flags &= ~(XFS_ALL_QUOTA_ACCT);

        sbflags = 0;

        if (flags == 0) {
                xfs_debug(mp, "%s: zero flags, m_qflags=%x\n",
                        __func__, mp->m_qflags);
                return XFS_ERROR(EINVAL);
        }

        /* No fs can turn on quotas with a delayed effect */
        ASSERT((flags & XFS_ALL_QUOTA_ACCT) == 0);

        /*
         * Can't enforce without accounting. We check the superblock
         * qflags here instead of m_qflags because rootfs can have
         * quota acct on ondisk without m_qflags' knowing.
         */
        if (((flags & XFS_UQUOTA_ACCT) == 0 &&
            (mp->m_sb.sb_qflags & XFS_UQUOTA_ACCT) == 0 &&
            (flags & XFS_UQUOTA_ENFD))
            ||
            ((flags & XFS_PQUOTA_ACCT) == 0 &&
            (mp->m_sb.sb_qflags & XFS_PQUOTA_ACCT) == 0 &&
            (flags & XFS_GQUOTA_ACCT) == 0 &&
            (mp->m_sb.sb_qflags & XFS_GQUOTA_ACCT) == 0 &&
            (flags & XFS_OQUOTA_ENFD))) {
                xfs_debug(mp,
                        "%s: Can't enforce without acct, flags=%x sbflags=%x\n",
                        __func__, flags, mp->m_sb.sb_qflags);
                return XFS_ERROR(EINVAL);
        }
        /*
         * If everything's up to-date incore, then don't waste time.
         */
        if ((mp->m_qflags & flags) == flags)
                return XFS_ERROR(EEXIST);

        /*
         * Change sb_qflags on disk but not incore mp->qflags
         * if this is the root filesystem.
         */
        spin_lock(&mp->m_sb_lock);
        qf = mp->m_sb.sb_qflags;
        mp->m_sb.sb_qflags = qf | flags;
        spin_unlock(&mp->m_sb_lock);

        /*
         * There's nothing to change if it's the same.
         */
        if ((qf & flags) == flags && sbflags == 0)
                return XFS_ERROR(EEXIST);
        sbflags |= XFS_SB_QFLAGS;

        if ((error = xfs_qm_write_sb_changes(mp, sbflags)))
                return (error);
        /*
         * If we aren't trying to switch on quota enforcement, we are done.
         */
        if  (((mp->m_sb.sb_qflags & XFS_UQUOTA_ACCT) !=
             (mp->m_qflags & XFS_UQUOTA_ACCT)) ||
             ((mp->m_sb.sb_qflags & XFS_PQUOTA_ACCT) !=
             (mp->m_qflags & XFS_PQUOTA_ACCT)) ||
             ((mp->m_sb.sb_qflags & XFS_GQUOTA_ACCT) !=
             (mp->m_qflags & XFS_GQUOTA_ACCT)) ||
            (flags & XFS_ALL_QUOTA_ENFD) == 0)
                return (0);

        if (! XFS_IS_QUOTA_RUNNING(mp))
                return XFS_ERROR(ESRCH);

        /*
         * Switch on quota enforcement in core.
         */
        mutex_lock(&mp->m_quotainfo->qi_quotaofflock);
        mp->m_qflags |= (flags & XFS_ALL_QUOTA_ENFD);
        mutex_unlock(&mp->m_quotainfo->qi_quotaofflock);

        return (0);
}


/*
 * Return quota status information, such as uquota-off, enforcements, etc.
 */
int
xfs_qm_scall_getqstat(
        struct xfs_mount        *mp,
        struct fs_quota_stat    *out)
{
        struct xfs_quotainfo    *q = mp->m_quotainfo;
        struct xfs_inode        *uip, *gip;
        boolean_t               tempuqip, tempgqip;

        uip = gip = NULL;
        tempuqip = tempgqip = B_FALSE;
        memset(out, 0, sizeof(fs_quota_stat_t));

        out->qs_version = FS_QSTAT_VERSION;
        if (!xfs_sb_version_hasquota(&mp->m_sb)) {
                out->qs_uquota.qfs_ino = NULLFSINO;
                out->qs_gquota.qfs_ino = NULLFSINO;
                return (0);
        }
        out->qs_flags = (__uint16_t) xfs_qm_export_flags(mp->m_qflags &
                                                        (XFS_ALL_QUOTA_ACCT|
                                                         XFS_ALL_QUOTA_ENFD));
        out->qs_pad = 0;
        out->qs_uquota.qfs_ino = mp->m_sb.sb_uquotino;
        out->qs_gquota.qfs_ino = mp->m_sb.sb_gquotino;

        if (q) {
                uip = q->qi_uquotaip;
                gip = q->qi_gquotaip;
        }
        if (!uip && mp->m_sb.sb_uquotino != NULLFSINO) {
                if (xfs_iget(mp, NULL, mp->m_sb.sb_uquotino,
                                        0, 0, &uip) == 0)
                        tempuqip = B_TRUE;
        }
        if (!gip && mp->m_sb.sb_gquotino != NULLFSINO) {
                if (xfs_iget(mp, NULL, mp->m_sb.sb_gquotino,
                                        0, 0, &gip) == 0)
                        tempgqip = B_TRUE;
        }
        if (uip) {
                out->qs_uquota.qfs_nblks = uip->i_d.di_nblocks;
                out->qs_uquota.qfs_nextents = uip->i_d.di_nextents;
                if (tempuqip)
                        IRELE(uip);
        }
        if (gip) {
                out->qs_gquota.qfs_nblks = gip->i_d.di_nblocks;
                out->qs_gquota.qfs_nextents = gip->i_d.di_nextents;
                if (tempgqip)
                        IRELE(gip);
        }
        if (q) {
                out->qs_incoredqs = q->qi_dquots;
                out->qs_btimelimit = q->qi_btimelimit;
                out->qs_itimelimit = q->qi_itimelimit;
                out->qs_rtbtimelimit = q->qi_rtbtimelimit;
                out->qs_bwarnlimit = q->qi_bwarnlimit;
                out->qs_iwarnlimit = q->qi_iwarnlimit;
        }
        return 0;
}

#define XFS_DQ_MASK \
        (FS_DQ_LIMIT_MASK | FS_DQ_TIMER_MASK | FS_DQ_WARNS_MASK)

/*
 * Adjust quota limits, and start/stop timers accordingly.
 */
int
xfs_qm_scall_setqlim(
        xfs_mount_t             *mp,
        xfs_dqid_t              id,
        uint                    type,
        fs_disk_quota_t         *newlim)
{
        struct xfs_quotainfo    *q = mp->m_quotainfo;
        xfs_disk_dquot_t        *ddq;
        xfs_dquot_t             *dqp;
        xfs_trans_t             *tp;
        int                     error;
        xfs_qcnt_t              hard, soft;

        if (newlim->d_fieldmask & ~XFS_DQ_MASK)
                return EINVAL;
        if ((newlim->d_fieldmask & XFS_DQ_MASK) == 0)
                return 0;

        tp = xfs_trans_alloc(mp, XFS_TRANS_QM_SETQLIM);
        if ((error = xfs_trans_reserve(tp, 0, sizeof(xfs_disk_dquot_t) + 128,
                                      0, 0, XFS_DEFAULT_LOG_COUNT))) {
                xfs_trans_cancel(tp, 0);
                return (error);
        }

        /*
         * We don't want to race with a quotaoff so take the quotaoff lock.
         * (We don't hold an inode lock, so there's nothing else to stop
         * a quotaoff from happening). (XXXThis doesn't currently happen
         * because we take the vfslock before calling xfs_qm_sysent).
         */
        mutex_lock(&q->qi_quotaofflock);

        /*
         * Get the dquot (locked), and join it to the transaction.
         * Allocate the dquot if this doesn't exist.
         */
        if ((error = xfs_qm_dqget(mp, NULL, id, type, XFS_QMOPT_DQALLOC, &dqp))) {
                xfs_trans_cancel(tp, XFS_TRANS_ABORT);
                ASSERT(error != ENOENT);
                goto out_unlock;
        }
        xfs_trans_dqjoin(tp, dqp);
        ddq = &dqp->q_core;

        /*
         * Make sure that hardlimits are >= soft limits before changing.
         */
        hard = (newlim->d_fieldmask & FS_DQ_BHARD) ?
                (xfs_qcnt_t) XFS_BB_TO_FSB(mp, newlim->d_blk_hardlimit) :
                        be64_to_cpu(ddq->d_blk_hardlimit);
        soft = (newlim->d_fieldmask & FS_DQ_BSOFT) ?
                (xfs_qcnt_t) XFS_BB_TO_FSB(mp, newlim->d_blk_softlimit) :
                        be64_to_cpu(ddq->d_blk_softlimit);
        if (hard == 0 || hard >= soft) {
                ddq->d_blk_hardlimit = cpu_to_be64(hard);
                ddq->d_blk_softlimit = cpu_to_be64(soft);
                if (id == 0) {
                        q->qi_bhardlimit = hard;
                        q->qi_bsoftlimit = soft;
                }
        } else {
                xfs_debug(mp, "blkhard %Ld < blksoft %Ld\n", hard, soft);
        }
        hard = (newlim->d_fieldmask & FS_DQ_RTBHARD) ?
                (xfs_qcnt_t) XFS_BB_TO_FSB(mp, newlim->d_rtb_hardlimit) :
                        be64_to_cpu(ddq->d_rtb_hardlimit);
        soft = (newlim->d_fieldmask & FS_DQ_RTBSOFT) ?
                (xfs_qcnt_t) XFS_BB_TO_FSB(mp, newlim->d_rtb_softlimit) :
                        be64_to_cpu(ddq->d_rtb_softlimit);
        if (hard == 0 || hard >= soft) {
                ddq->d_rtb_hardlimit = cpu_to_be64(hard);
                ddq->d_rtb_softlimit = cpu_to_be64(soft);
                if (id == 0) {
                        q->qi_rtbhardlimit = hard;
                        q->qi_rtbsoftlimit = soft;
                }
        } else {
                xfs_debug(mp, "rtbhard %Ld < rtbsoft %Ld\n", hard, soft);
        }

        hard = (newlim->d_fieldmask & FS_DQ_IHARD) ?
                (xfs_qcnt_t) newlim->d_ino_hardlimit :
                        be64_to_cpu(ddq->d_ino_hardlimit);
        soft = (newlim->d_fieldmask & FS_DQ_ISOFT) ?
                (xfs_qcnt_t) newlim->d_ino_softlimit :
                        be64_to_cpu(ddq->d_ino_softlimit);
        if (hard == 0 || hard >= soft) {
                ddq->d_ino_hardlimit = cpu_to_be64(hard);
                ddq->d_ino_softlimit = cpu_to_be64(soft);
                if (id == 0) {
                        q->qi_ihardlimit = hard;
                        q->qi_isoftlimit = soft;
                }
        } else {
                xfs_debug(mp, "ihard %Ld < isoft %Ld\n", hard, soft);
        }

        /*
         * Update warnings counter(s) if requested
         */
        if (newlim->d_fieldmask & FS_DQ_BWARNS)
                ddq->d_bwarns = cpu_to_be16(newlim->d_bwarns);
        if (newlim->d_fieldmask & FS_DQ_IWARNS)
                ddq->d_iwarns = cpu_to_be16(newlim->d_iwarns);
        if (newlim->d_fieldmask & FS_DQ_RTBWARNS)
                ddq->d_rtbwarns = cpu_to_be16(newlim->d_rtbwarns);

        if (id == 0) {
                /*
                 * Timelimits for the super user set the relative time
                 * the other users can be over quota for this file system.
                 * If it is zero a default is used.  Ditto for the default
                 * soft and hard limit values (already done, above), and
                 * for warnings.
                 */
                if (newlim->d_fieldmask & FS_DQ_BTIMER) {
                        q->qi_btimelimit = newlim->d_btimer;
                        ddq->d_btimer = cpu_to_be32(newlim->d_btimer);
                }
                if (newlim->d_fieldmask & FS_DQ_ITIMER) {
                        q->qi_itimelimit = newlim->d_itimer;
                        ddq->d_itimer = cpu_to_be32(newlim->d_itimer);
                }
                if (newlim->d_fieldmask & FS_DQ_RTBTIMER) {
                        q->qi_rtbtimelimit = newlim->d_rtbtimer;
                        ddq->d_rtbtimer = cpu_to_be32(newlim->d_rtbtimer);
                }
                if (newlim->d_fieldmask & FS_DQ_BWARNS)
                        q->qi_bwarnlimit = newlim->d_bwarns;
                if (newlim->d_fieldmask & FS_DQ_IWARNS)
                        q->qi_iwarnlimit = newlim->d_iwarns;
                if (newlim->d_fieldmask & FS_DQ_RTBWARNS)
                        q->qi_rtbwarnlimit = newlim->d_rtbwarns;
        } else {
                /*
                 * If the user is now over quota, start the timelimit.
                 * The user will not be 'warned'.
                 * Note that we keep the timers ticking, whether enforcement
                 * is on or off. We don't really want to bother with iterating
                 * over all ondisk dquots and turning the timers on/off.
                 */
                xfs_qm_adjust_dqtimers(mp, ddq);
        }
        dqp->dq_flags |= XFS_DQ_DIRTY;
        xfs_trans_log_dquot(tp, dqp);

        error = xfs_trans_commit(tp, 0);
        xfs_qm_dqrele(dqp);

 out_unlock:
        mutex_unlock(&q->qi_quotaofflock);
        return error;
}

int
xfs_qm_scall_getquota(
        xfs_mount_t     *mp,
        xfs_dqid_t      id,
        uint            type,
        fs_disk_quota_t *out)
{
        xfs_dquot_t     *dqp;
        int             error;

        /*
         * Try to get the dquot. We don't want it allocated on disk, so
         * we aren't passing the XFS_QMOPT_DOALLOC flag. If it doesn't
         * exist, we'll get ENOENT back.
         */
        if ((error = xfs_qm_dqget(mp, NULL, id, type, 0, &dqp))) {
                return (error);
        }

        /*
         * If everything's NULL, this dquot doesn't quite exist as far as
         * our utility programs are concerned.
         */
        if (XFS_IS_DQUOT_UNINITIALIZED(dqp)) {
                xfs_qm_dqput(dqp);
                return XFS_ERROR(ENOENT);
        }
        /*
         * Convert the disk dquot to the exportable format
         */
        xfs_qm_export_dquot(mp, &dqp->q_core, out);
        xfs_qm_dqput(dqp);
        return (error ? XFS_ERROR(EFAULT) : 0);
}


STATIC int
xfs_qm_log_quotaoff_end(
        xfs_mount_t             *mp,
        xfs_qoff_logitem_t      *startqoff,
        uint                    flags)
{
        xfs_trans_t             *tp;
        int                     error;
        xfs_qoff_logitem_t      *qoffi;

        tp = xfs_trans_alloc(mp, XFS_TRANS_QM_QUOTAOFF_END);

        if ((error = xfs_trans_reserve(tp, 0, sizeof(xfs_qoff_logitem_t) * 2,
                                      0, 0, XFS_DEFAULT_LOG_COUNT))) {
                xfs_trans_cancel(tp, 0);
                return (error);
        }

        qoffi = xfs_trans_get_qoff_item(tp, startqoff,
                                        flags & XFS_ALL_QUOTA_ACCT);
        xfs_trans_log_quotaoff_item(tp, qoffi);

        /*
         * We have to make sure that the transaction is secure on disk before we
         * return and actually stop quota accounting. So, make it synchronous.
         * We don't care about quotoff's performance.
         */
        xfs_trans_set_sync(tp);
        error = xfs_trans_commit(tp, 0);
        return (error);
}


STATIC int
xfs_qm_log_quotaoff(
        xfs_mount_t            *mp,
        xfs_qoff_logitem_t     **qoffstartp,
        uint                   flags)
{
        xfs_trans_t            *tp;
        int                     error;
        xfs_qoff_logitem_t     *qoffi=NULL;
        uint                    oldsbqflag=0;

        tp = xfs_trans_alloc(mp, XFS_TRANS_QM_QUOTAOFF);
        if ((error = xfs_trans_reserve(tp, 0,
                                      sizeof(xfs_qoff_logitem_t) * 2 +
                                      mp->m_sb.sb_sectsize + 128,
                                      0,
                                      0,
                                      XFS_DEFAULT_LOG_COUNT))) {
                goto error0;
        }

        qoffi = xfs_trans_get_qoff_item(tp, NULL, flags & XFS_ALL_QUOTA_ACCT);
        xfs_trans_log_quotaoff_item(tp, qoffi);

        spin_lock(&mp->m_sb_lock);
        oldsbqflag = mp->m_sb.sb_qflags;
        mp->m_sb.sb_qflags = (mp->m_qflags & ~(flags)) & XFS_MOUNT_QUOTA_ALL;
        spin_unlock(&mp->m_sb_lock);

        xfs_mod_sb(tp, XFS_SB_QFLAGS);

        /*
         * We have to make sure that the transaction is secure on disk before we
         * return and actually stop quota accounting. So, make it synchronous.
         * We don't care about quotoff's performance.
         */
        xfs_trans_set_sync(tp);
        error = xfs_trans_commit(tp, 0);

error0:
        if (error) {
                xfs_trans_cancel(tp, 0);
                /*
                 * No one else is modifying sb_qflags, so this is OK.
                 * We still hold the quotaofflock.
                 */
                spin_lock(&mp->m_sb_lock);
                mp->m_sb.sb_qflags = oldsbqflag;
                spin_unlock(&mp->m_sb_lock);
        }
        *qoffstartp = qoffi;
        return (error);
}


/*
 * Translate an internal style on-disk-dquot to the exportable format.
 * The main differences are that the counters/limits are all in Basic
 * Blocks (BBs) instead of the internal FSBs, and all on-disk data has
 * to be converted to the native endianness.
 */
STATIC void
xfs_qm_export_dquot(
        xfs_mount_t             *mp,
        xfs_disk_dquot_t        *src,
        struct fs_disk_quota    *dst)
{
        memset(dst, 0, sizeof(*dst));
        dst->d_version = FS_DQUOT_VERSION;  /* different from src->d_version */
        dst->d_flags = xfs_qm_export_qtype_flags(src->d_flags);
        dst->d_id = be32_to_cpu(src->d_id);
        dst->d_blk_hardlimit =
                XFS_FSB_TO_BB(mp, be64_to_cpu(src->d_blk_hardlimit));
        dst->d_blk_softlimit =
                XFS_FSB_TO_BB(mp, be64_to_cpu(src->d_blk_softlimit));
        dst->d_ino_hardlimit = be64_to_cpu(src->d_ino_hardlimit);
        dst->d_ino_softlimit = be64_to_cpu(src->d_ino_softlimit);
        dst->d_bcount = XFS_FSB_TO_BB(mp, be64_to_cpu(src->d_bcount));
        dst->d_icount = be64_to_cpu(src->d_icount);
        dst->d_btimer = be32_to_cpu(src->d_btimer);
        dst->d_itimer = be32_to_cpu(src->d_itimer);
        dst->d_iwarns = be16_to_cpu(src->d_iwarns);
        dst->d_bwarns = be16_to_cpu(src->d_bwarns);
        dst->d_rtb_hardlimit =
                XFS_FSB_TO_BB(mp, be64_to_cpu(src->d_rtb_hardlimit));
        dst->d_rtb_softlimit =
                XFS_FSB_TO_BB(mp, be64_to_cpu(src->d_rtb_softlimit));
        dst->d_rtbcount = XFS_FSB_TO_BB(mp, be64_to_cpu(src->d_rtbcount));
        dst->d_rtbtimer = be32_to_cpu(src->d_rtbtimer);
        dst->d_rtbwarns = be16_to_cpu(src->d_rtbwarns);

        /*
         * Internally, we don't reset all the timers when quota enforcement
         * gets turned off. No need to confuse the user level code,
         * so return zeroes in that case.
         */
        if ((!XFS_IS_UQUOTA_ENFORCED(mp) && src->d_flags == XFS_DQ_USER) ||
            (!XFS_IS_OQUOTA_ENFORCED(mp) &&
                        (src->d_flags & (XFS_DQ_PROJ | XFS_DQ_GROUP)))) {
                dst->d_btimer = 0;
                dst->d_itimer = 0;
                dst->d_rtbtimer = 0;
        }

#ifdef DEBUG
        if (((XFS_IS_UQUOTA_ENFORCED(mp) && dst->d_flags == FS_USER_QUOTA) ||
             (XFS_IS_OQUOTA_ENFORCED(mp) &&
                        (dst->d_flags & (FS_PROJ_QUOTA | FS_GROUP_QUOTA)))) &&
            dst->d_id != 0) {
                if (((int) dst->d_bcount >= (int) dst->d_blk_softlimit) &&
                    (dst->d_blk_softlimit > 0)) {
                        ASSERT(dst->d_btimer != 0);
                }
                if (((int) dst->d_icount >= (int) dst->d_ino_softlimit) &&
                    (dst->d_ino_softlimit > 0)) {
                        ASSERT(dst->d_itimer != 0);
                }
        }
#endif
}

STATIC uint
xfs_qm_export_qtype_flags(
        uint flags)
{
        /*
         * Can't be more than one, or none.
         */
        ASSERT((flags & (FS_PROJ_QUOTA | FS_USER_QUOTA)) !=
                (FS_PROJ_QUOTA | FS_USER_QUOTA));
        ASSERT((flags & (FS_PROJ_QUOTA | FS_GROUP_QUOTA)) !=
                (FS_PROJ_QUOTA | FS_GROUP_QUOTA));
        ASSERT((flags & (FS_USER_QUOTA | FS_GROUP_QUOTA)) !=
                (FS_USER_QUOTA | FS_GROUP_QUOTA));
        ASSERT((flags & (FS_PROJ_QUOTA|FS_USER_QUOTA|FS_GROUP_QUOTA)) != 0);

        return (flags & XFS_DQ_USER) ?
                FS_USER_QUOTA : (flags & XFS_DQ_PROJ) ?
                        FS_PROJ_QUOTA : FS_GROUP_QUOTA;
}

STATIC uint
xfs_qm_export_flags(
        uint flags)
{
        uint uflags;

        uflags = 0;
        if (flags & XFS_UQUOTA_ACCT)
                uflags |= FS_QUOTA_UDQ_ACCT;
        if (flags & XFS_PQUOTA_ACCT)
                uflags |= FS_QUOTA_PDQ_ACCT;
        if (flags & XFS_GQUOTA_ACCT)
                uflags |= FS_QUOTA_GDQ_ACCT;
        if (flags & XFS_UQUOTA_ENFD)
                uflags |= FS_QUOTA_UDQ_ENFD;
        if (flags & (XFS_OQUOTA_ENFD)) {
                uflags |= (flags & XFS_GQUOTA_ACCT) ?
                        FS_QUOTA_GDQ_ENFD : FS_QUOTA_PDQ_ENFD;
        }
        return (uflags);
}


STATIC int
xfs_dqrele_inode(
        struct xfs_inode        *ip,
        struct xfs_perag        *pag,
        int                     flags)
{
        /* skip quota inodes */
        if (ip == ip->i_mount->m_quotainfo->qi_uquotaip ||
            ip == ip->i_mount->m_quotainfo->qi_gquotaip) {
                ASSERT(ip->i_udquot == NULL);
                ASSERT(ip->i_gdquot == NULL);
                return 0;
        }

        xfs_ilock(ip, XFS_ILOCK_EXCL);
        if ((flags & XFS_UQUOTA_ACCT) && ip->i_udquot) {
                xfs_qm_dqrele(ip->i_udquot);
                ip->i_udquot = NULL;
        }
        if (flags & (XFS_PQUOTA_ACCT|XFS_GQUOTA_ACCT) && ip->i_gdquot) {
                xfs_qm_dqrele(ip->i_gdquot);
                ip->i_gdquot = NULL;
        }
        xfs_iunlock(ip, XFS_ILOCK_EXCL);
        return 0;
}


/*
 * Go thru all the inodes in the file system, releasing their dquots.
 *
 * Note that the mount structure gets modified to indicate that quotas are off
 * AFTER this, in the case of quotaoff.
 */
void
xfs_qm_dqrele_all_inodes(
        struct xfs_mount *mp,
        uint             flags)
{
        ASSERT(mp->m_quotainfo);
        xfs_inode_ag_iterator(mp, xfs_dqrele_inode, flags);
}