// SPDX-License-Identifier: GPL-2.0
/*
 * Quota code necessary even when VFS quota support is not compiled
 * into the kernel.  The interesting stuff is over in dquot.c, here
 * we have symbols for initial quotactl(2) handling, the sysctl(2)
 * variables, etc - things needed even when quota support disabled.
 */

#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/slab.h>
#include <asm/current.h>
#include <linux/blkdev.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/types.h>
#include <linux/mount.h>
#include <linux/writeback.h>
#include <linux/nospec.h>
#include "compat.h"
#include "../internal.h"

static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
                                     qid_t id)
{
        switch (cmd) {
        /* these commands do not require any special privilegues */
        case Q_GETFMT:
        case Q_SYNC:
        case Q_GETINFO:
        case Q_XGETQSTAT:
        case Q_XGETQSTATV:
        case Q_XQUOTASYNC:
                break;
        /* allow to query information for dquots we "own" */
        case Q_GETQUOTA:
        case Q_XGETQUOTA:
                if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) ||
                    (type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
                        break;
                fallthrough;
        default:
                if (!capable(CAP_SYS_ADMIN))
                        return -EPERM;
        }

        return security_quotactl(cmd, type, id, sb);
}

static void quota_sync_one(struct super_block *sb, void *arg)
{
        int type = *(int *)arg;

        if (sb->s_qcop && sb->s_qcop->quota_sync &&
            (sb->s_quota_types & (1 << type)))
                sb->s_qcop->quota_sync(sb, type);
}

static int quota_sync_all(int type)
{
        int ret;

        ret = security_quotactl(Q_SYNC, type, 0, NULL);
        if (!ret)
                iterate_supers(quota_sync_one, &type);
        return ret;
}

unsigned int qtype_enforce_flag(int type)
{
        switch (type) {
        case USRQUOTA:
                return FS_QUOTA_UDQ_ENFD;
        case GRPQUOTA:
                return FS_QUOTA_GDQ_ENFD;
        case PRJQUOTA:
                return FS_QUOTA_PDQ_ENFD;
        }
        return 0;
}

static int quota_quotaon(struct super_block *sb, int type, qid_t id,
                         const struct path *path)
{
        if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_enable)
                return -ENOSYS;
        if (sb->s_qcop->quota_enable)
                return sb->s_qcop->quota_enable(sb, qtype_enforce_flag(type));
        if (IS_ERR(path))
                return PTR_ERR(path);
        return sb->s_qcop->quota_on(sb, type, id, path);
}

static int quota_quotaoff(struct super_block *sb, int type)
{
        if (!sb->s_qcop->quota_off && !sb->s_qcop->quota_disable)
                return -ENOSYS;
        if (sb->s_qcop->quota_disable)
                return sb->s_qcop->quota_disable(sb, qtype_enforce_flag(type));
        return sb->s_qcop->quota_off(sb, type);
}

static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
{
        __u32 fmt;

        if (!sb_has_quota_active(sb, type))
                return -ESRCH;
        fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
        if (copy_to_user(addr, &fmt, sizeof(fmt)))
                return -EFAULT;
        return 0;
}

static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
{
        struct qc_state state;
        struct qc_type_state *tstate;
        struct if_dqinfo uinfo;
        int ret;

        if (!sb->s_qcop->get_state)
                return -ENOSYS;
        ret = sb->s_qcop->get_state(sb, &state);
        if (ret)
                return ret;
        tstate = state.s_state + type;
        if (!(tstate->flags & QCI_ACCT_ENABLED))
                return -ESRCH;
        memset(&uinfo, 0, sizeof(uinfo));
        uinfo.dqi_bgrace = tstate->spc_timelimit;
        uinfo.dqi_igrace = tstate->ino_timelimit;
        if (tstate->flags & QCI_SYSFILE)
                uinfo.dqi_flags |= DQF_SYS_FILE;
        if (tstate->flags & QCI_ROOT_SQUASH)
                uinfo.dqi_flags |= DQF_ROOT_SQUASH;
        uinfo.dqi_valid = IIF_ALL;
        if (copy_to_user(addr, &uinfo, sizeof(uinfo)))
                return -EFAULT;
        return 0;
}

static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
{
        struct if_dqinfo info;
        struct qc_info qinfo;

        if (copy_from_user(&info, addr, sizeof(info)))
                return -EFAULT;
        if (!sb->s_qcop->set_info)
                return -ENOSYS;
        if (info.dqi_valid & ~(IIF_FLAGS | IIF_BGRACE | IIF_IGRACE))
                return -EINVAL;
        memset(&qinfo, 0, sizeof(qinfo));
        if (info.dqi_valid & IIF_FLAGS) {
                if (info.dqi_flags & ~DQF_SETINFO_MASK)
                        return -EINVAL;
                if (info.dqi_flags & DQF_ROOT_SQUASH)
                        qinfo.i_flags |= QCI_ROOT_SQUASH;
                qinfo.i_fieldmask |= QC_FLAGS;
        }
        if (info.dqi_valid & IIF_BGRACE) {
                qinfo.i_spc_timelimit = info.dqi_bgrace;
                qinfo.i_fieldmask |= QC_SPC_TIMER;
        }
        if (info.dqi_valid & IIF_IGRACE) {
                qinfo.i_ino_timelimit = info.dqi_igrace;
                qinfo.i_fieldmask |= QC_INO_TIMER;
        }
        return sb->s_qcop->set_info(sb, type, &qinfo);
}

static inline qsize_t qbtos(qsize_t blocks)
{
        return blocks << QIF_DQBLKSIZE_BITS;
}

static inline qsize_t stoqb(qsize_t space)
{
        return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
}

static void copy_to_if_dqblk(struct if_dqblk *dst, struct qc_dqblk *src)
{
        memset(dst, 0, sizeof(*dst));
        dst->dqb_bhardlimit = stoqb(src->d_spc_hardlimit);
        dst->dqb_bsoftlimit = stoqb(src->d_spc_softlimit);
        dst->dqb_curspace = src->d_space;
        dst->dqb_ihardlimit = src->d_ino_hardlimit;
        dst->dqb_isoftlimit = src->d_ino_softlimit;
        dst->dqb_curinodes = src->d_ino_count;
        dst->dqb_btime = src->d_spc_timer;
        dst->dqb_itime = src->d_ino_timer;
        dst->dqb_valid = QIF_ALL;
}

static int quota_getquota(struct super_block *sb, int type, qid_t id,
                          void __user *addr)
{
        struct kqid qid;
        struct qc_dqblk fdq;
        struct if_dqblk idq;
        int ret;

        if (!sb->s_qcop->get_dqblk)
                return -ENOSYS;
        qid = make_kqid(current_user_ns(), type, id);
        if (!qid_has_mapping(sb->s_user_ns, qid))
                return -EINVAL;
        ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
        if (ret)
                return ret;
        copy_to_if_dqblk(&idq, &fdq);

        if (compat_need_64bit_alignment_fixup()) {
                struct compat_if_dqblk __user *compat_dqblk = addr;

                if (copy_to_user(compat_dqblk, &idq, sizeof(*compat_dqblk)))
                        return -EFAULT;
                if (put_user(idq.dqb_valid, &compat_dqblk->dqb_valid))
                        return -EFAULT;
        } else {
                if (copy_to_user(addr, &idq, sizeof(idq)))
                        return -EFAULT;
        }
        return 0;
}

/*
 * Return quota for next active quota >= this id, if any exists,
 * otherwise return -ENOENT via ->get_nextdqblk
 */
static int quota_getnextquota(struct super_block *sb, int type, qid_t id,
                          void __user *addr)
{
        struct kqid qid;
        struct qc_dqblk fdq;
        struct if_nextdqblk idq;
        int ret;

        if (!sb->s_qcop->get_nextdqblk)
                return -ENOSYS;
        qid = make_kqid(current_user_ns(), type, id);
        if (!qid_has_mapping(sb->s_user_ns, qid))
                return -EINVAL;
        ret = sb->s_qcop->get_nextdqblk(sb, &qid, &fdq);
        if (ret)
                return ret;
        /* struct if_nextdqblk is a superset of struct if_dqblk */
        copy_to_if_dqblk((struct if_dqblk *)&idq, &fdq);
        idq.dqb_id = from_kqid(current_user_ns(), qid);
        if (copy_to_user(addr, &idq, sizeof(idq)))
                return -EFAULT;
        return 0;
}

static void copy_from_if_dqblk(struct qc_dqblk *dst, struct if_dqblk *src)
{
        dst->d_spc_hardlimit = qbtos(src->dqb_bhardlimit);
        dst->d_spc_softlimit = qbtos(src->dqb_bsoftlimit);
        dst->d_space = src->dqb_curspace;
        dst->d_ino_hardlimit = src->dqb_ihardlimit;
        dst->d_ino_softlimit = src->dqb_isoftlimit;
        dst->d_ino_count = src->dqb_curinodes;
        dst->d_spc_timer = src->dqb_btime;
        dst->d_ino_timer = src->dqb_itime;

        dst->d_fieldmask = 0;
        if (src->dqb_valid & QIF_BLIMITS)
                dst->d_fieldmask |= QC_SPC_SOFT | QC_SPC_HARD;
        if (src->dqb_valid & QIF_SPACE)
                dst->d_fieldmask |= QC_SPACE;
        if (src->dqb_valid & QIF_ILIMITS)
                dst->d_fieldmask |= QC_INO_SOFT | QC_INO_HARD;
        if (src->dqb_valid & QIF_INODES)
                dst->d_fieldmask |= QC_INO_COUNT;
        if (src->dqb_valid & QIF_BTIME)
                dst->d_fieldmask |= QC_SPC_TIMER;
        if (src->dqb_valid & QIF_ITIME)
                dst->d_fieldmask |= QC_INO_TIMER;
}

static int quota_setquota(struct super_block *sb, int type, qid_t id,
                          void __user *addr)
{
        struct qc_dqblk fdq;
        struct if_dqblk idq;
        struct kqid qid;

        if (compat_need_64bit_alignment_fixup()) {
                struct compat_if_dqblk __user *compat_dqblk = addr;

                if (copy_from_user(&idq, compat_dqblk, sizeof(*compat_dqblk)) ||
                    get_user(idq.dqb_valid, &compat_dqblk->dqb_valid))
                        return -EFAULT;
        } else {
                if (copy_from_user(&idq, addr, sizeof(idq)))
                        return -EFAULT;
        }
        if (!sb->s_qcop->set_dqblk)
                return -ENOSYS;
        qid = make_kqid(current_user_ns(), type, id);
        if (!qid_has_mapping(sb->s_user_ns, qid))
                return -EINVAL;
        copy_from_if_dqblk(&fdq, &idq);
        return sb->s_qcop->set_dqblk(sb, qid, &fdq);
}

static int quota_enable(struct super_block *sb, void __user *addr)
{
        __u32 flags;

        if (copy_from_user(&flags, addr, sizeof(flags)))
                return -EFAULT;
        if (!sb->s_qcop->quota_enable)
                return -ENOSYS;
        return sb->s_qcop->quota_enable(sb, flags);
}

static int quota_disable(struct super_block *sb, void __user *addr)
{
        __u32 flags;

        if (copy_from_user(&flags, addr, sizeof(flags)))
                return -EFAULT;
        if (!sb->s_qcop->quota_disable)
                return -ENOSYS;
        return sb->s_qcop->quota_disable(sb, flags);
}

static int quota_state_to_flags(struct qc_state *state)
{
        int flags = 0;

        if (state->s_state[USRQUOTA].flags & QCI_ACCT_ENABLED)
                flags |= FS_QUOTA_UDQ_ACCT;
        if (state->s_state[USRQUOTA].flags & QCI_LIMITS_ENFORCED)
                flags |= FS_QUOTA_UDQ_ENFD;
        if (state->s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)
                flags |= FS_QUOTA_GDQ_ACCT;
        if (state->s_state[GRPQUOTA].flags & QCI_LIMITS_ENFORCED)
                flags |= FS_QUOTA_GDQ_ENFD;
        if (state->s_state[PRJQUOTA].flags & QCI_ACCT_ENABLED)
                flags |= FS_QUOTA_PDQ_ACCT;
        if (state->s_state[PRJQUOTA].flags & QCI_LIMITS_ENFORCED)
                flags |= FS_QUOTA_PDQ_ENFD;
        return flags;
}

static int quota_getstate(struct super_block *sb, int type,
                          struct fs_quota_stat *fqs)
{
        struct qc_state state;
        int ret;

        memset(&state, 0, sizeof (struct qc_state));
        ret = sb->s_qcop->get_state(sb, &state);
        if (ret < 0)
                return ret;

        memset(fqs, 0, sizeof(*fqs));
        fqs->qs_version = FS_QSTAT_VERSION;
        fqs->qs_flags = quota_state_to_flags(&state);
        /* No quota enabled? */
        if (!fqs->qs_flags)
                return -ENOSYS;
        fqs->qs_incoredqs = state.s_incoredqs;

        fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
        fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
        fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
        fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
        fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;

        /* Inodes may be allocated even if inactive; copy out if present */
        if (state.s_state[USRQUOTA].ino) {
                fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
                fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
                fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
        }
        if (state.s_state[GRPQUOTA].ino) {
                fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
                fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
                fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
        }
        if (state.s_state[PRJQUOTA].ino) {
                /*
                 * Q_XGETQSTAT doesn't have room for both group and project
                 * quotas.  So, allow the project quota values to be copied out
                 * only if there is no group quota information available.
                 */
                if (!(state.s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)) {
                        fqs->qs_gquota.qfs_ino = state.s_state[PRJQUOTA].ino;
                        fqs->qs_gquota.qfs_nblks =
                                        state.s_state[PRJQUOTA].blocks;
                        fqs->qs_gquota.qfs_nextents =
                                        state.s_state[PRJQUOTA].nextents;
                }
        }
        return 0;
}

static int compat_copy_fs_qfilestat(struct compat_fs_qfilestat __user *to,
                struct fs_qfilestat *from)
{
        if (copy_to_user(to, from, sizeof(*to)) ||
            put_user(from->qfs_nextents, &to->qfs_nextents))
                return -EFAULT;
        return 0;
}

static int compat_copy_fs_quota_stat(struct compat_fs_quota_stat __user *to,
                struct fs_quota_stat *from)
{
        if (put_user(from->qs_version, &to->qs_version) ||
            put_user(from->qs_flags, &to->qs_flags) ||
            put_user(from->qs_pad, &to->qs_pad) ||
            compat_copy_fs_qfilestat(&to->qs_uquota, &from->qs_uquota) ||
            compat_copy_fs_qfilestat(&to->qs_gquota, &from->qs_gquota) ||
            put_user(from->qs_incoredqs, &to->qs_incoredqs) ||
            put_user(from->qs_btimelimit, &to->qs_btimelimit) ||
            put_user(from->qs_itimelimit, &to->qs_itimelimit) ||
            put_user(from->qs_rtbtimelimit, &to->qs_rtbtimelimit) ||
            put_user(from->qs_bwarnlimit, &to->qs_bwarnlimit) ||
            put_user(from->qs_iwarnlimit, &to->qs_iwarnlimit))
                return -EFAULT;
        return 0;
}

static int quota_getxstate(struct super_block *sb, int type, void __user *addr)
{
        struct fs_quota_stat fqs;
        int ret;

        if (!sb->s_qcop->get_state)
                return -ENOSYS;
        ret = quota_getstate(sb, type, &fqs);
        if (ret)
                return ret;

        if (compat_need_64bit_alignment_fixup())
                return compat_copy_fs_quota_stat(addr, &fqs);
        if (copy_to_user(addr, &fqs, sizeof(fqs)))
                return -EFAULT;
        return 0;
}

static int quota_getstatev(struct super_block *sb, int type,
                           struct fs_quota_statv *fqs)
{
        struct qc_state state;
        int ret;

        memset(&state, 0, sizeof (struct qc_state));
        ret = sb->s_qcop->get_state(sb, &state);
        if (ret < 0)
                return ret;

        memset(fqs, 0, sizeof(*fqs));
        fqs->qs_version = FS_QSTAT_VERSION;
        fqs->qs_flags = quota_state_to_flags(&state);
        /* No quota enabled? */
        if (!fqs->qs_flags)
                return -ENOSYS;
        fqs->qs_incoredqs = state.s_incoredqs;

        fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
        fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
        fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
        fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
        fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
        fqs->qs_rtbwarnlimit = state.s_state[type].rt_spc_warnlimit;

        /* Inodes may be allocated even if inactive; copy out if present */
        if (state.s_state[USRQUOTA].ino) {
                fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
                fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
                fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
        }
        if (state.s_state[GRPQUOTA].ino) {
                fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
                fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
                fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
        }
        if (state.s_state[PRJQUOTA].ino) {
                fqs->qs_pquota.qfs_ino = state.s_state[PRJQUOTA].ino;
                fqs->qs_pquota.qfs_nblks = state.s_state[PRJQUOTA].blocks;
                fqs->qs_pquota.qfs_nextents = state.s_state[PRJQUOTA].nextents;
        }
        return 0;
}

static int quota_getxstatev(struct super_block *sb, int type, void __user *addr)
{
        struct fs_quota_statv fqs;
        int ret;

        if (!sb->s_qcop->get_state)
                return -ENOSYS;

        memset(&fqs, 0, sizeof(fqs));
        if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
                return -EFAULT;

        /* If this kernel doesn't support user specified version, fail */
        switch (fqs.qs_version) {
        case FS_QSTATV_VERSION1:
                break;
        default:
                return -EINVAL;
        }
        ret = quota_getstatev(sb, type, &fqs);
        if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
                return -EFAULT;
        return ret;
}

/*
 * XFS defines BBTOB and BTOBB macros inside fs/xfs/ and we cannot move them
 * out of there as xfsprogs rely on definitions being in that header file. So
 * just define same functions here for quota purposes.
 */
#define XFS_BB_SHIFT 9

static inline u64 quota_bbtob(u64 blocks)
{
        return blocks << XFS_BB_SHIFT;
}

static inline u64 quota_btobb(u64 bytes)
{
        return (bytes + (1 << XFS_BB_SHIFT) - 1) >> XFS_BB_SHIFT;
}

static inline s64 copy_from_xfs_dqblk_ts(const struct fs_disk_quota *d,
                __s32 timer, __s8 timer_hi)
{
        if (d->d_fieldmask & FS_DQ_BIGTIME)
                return (u32)timer | (s64)timer_hi << 32;
        return timer;
}

static void copy_from_xfs_dqblk(struct qc_dqblk *dst, struct fs_disk_quota *src)
{
        dst->d_spc_hardlimit = quota_bbtob(src->d_blk_hardlimit);
        dst->d_spc_softlimit = quota_bbtob(src->d_blk_softlimit);
        dst->d_ino_hardlimit = src->d_ino_hardlimit;
        dst->d_ino_softlimit = src->d_ino_softlimit;
        dst->d_space = quota_bbtob(src->d_bcount);
        dst->d_ino_count = src->d_icount;
        dst->d_ino_timer = copy_from_xfs_dqblk_ts(src, src->d_itimer,
                                                  src->d_itimer_hi);
        dst->d_spc_timer = copy_from_xfs_dqblk_ts(src, src->d_btimer,
                                                  src->d_btimer_hi);
        dst->d_ino_warns = src->d_iwarns;
        dst->d_spc_warns = src->d_bwarns;
        dst->d_rt_spc_hardlimit = quota_bbtob(src->d_rtb_hardlimit);
        dst->d_rt_spc_softlimit = quota_bbtob(src->d_rtb_softlimit);
        dst->d_rt_space = quota_bbtob(src->d_rtbcount);
        dst->d_rt_spc_timer = copy_from_xfs_dqblk_ts(src, src->d_rtbtimer,
                                                     src->d_rtbtimer_hi);
        dst->d_rt_spc_warns = src->d_rtbwarns;
        dst->d_fieldmask = 0;
        if (src->d_fieldmask & FS_DQ_ISOFT)
                dst->d_fieldmask |= QC_INO_SOFT;
        if (src->d_fieldmask & FS_DQ_IHARD)
                dst->d_fieldmask |= QC_INO_HARD;
        if (src->d_fieldmask & FS_DQ_BSOFT)
                dst->d_fieldmask |= QC_SPC_SOFT;
        if (src->d_fieldmask & FS_DQ_BHARD)
                dst->d_fieldmask |= QC_SPC_HARD;
        if (src->d_fieldmask & FS_DQ_RTBSOFT)
                dst->d_fieldmask |= QC_RT_SPC_SOFT;
        if (src->d_fieldmask & FS_DQ_RTBHARD)
                dst->d_fieldmask |= QC_RT_SPC_HARD;
        if (src->d_fieldmask & FS_DQ_BTIMER)
                dst->d_fieldmask |= QC_SPC_TIMER;
        if (src->d_fieldmask & FS_DQ_ITIMER)
                dst->d_fieldmask |= QC_INO_TIMER;
        if (src->d_fieldmask & FS_DQ_RTBTIMER)
                dst->d_fieldmask |= QC_RT_SPC_TIMER;
        if (src->d_fieldmask & FS_DQ_BWARNS)
                dst->d_fieldmask |= QC_SPC_WARNS;
        if (src->d_fieldmask & FS_DQ_IWARNS)
                dst->d_fieldmask |= QC_INO_WARNS;
        if (src->d_fieldmask & FS_DQ_RTBWARNS)
                dst->d_fieldmask |= QC_RT_SPC_WARNS;
        if (src->d_fieldmask & FS_DQ_BCOUNT)
                dst->d_fieldmask |= QC_SPACE;
        if (src->d_fieldmask & FS_DQ_ICOUNT)
                dst->d_fieldmask |= QC_INO_COUNT;
        if (src->d_fieldmask & FS_DQ_RTBCOUNT)
                dst->d_fieldmask |= QC_RT_SPACE;
}

static void copy_qcinfo_from_xfs_dqblk(struct qc_info *dst,
                                       struct fs_disk_quota *src)
{
        memset(dst, 0, sizeof(*dst));
        dst->i_spc_timelimit = src->d_btimer;
        dst->i_ino_timelimit = src->d_itimer;
        dst->i_rt_spc_timelimit = src->d_rtbtimer;
        dst->i_ino_warnlimit = src->d_iwarns;
        dst->i_spc_warnlimit = src->d_bwarns;
        dst->i_rt_spc_warnlimit = src->d_rtbwarns;
        if (src->d_fieldmask & FS_DQ_BWARNS)
                dst->i_fieldmask |= QC_SPC_WARNS;
        if (src->d_fieldmask & FS_DQ_IWARNS)
                dst->i_fieldmask |= QC_INO_WARNS;
        if (src->d_fieldmask & FS_DQ_RTBWARNS)
                dst->i_fieldmask |= QC_RT_SPC_WARNS;
        if (src->d_fieldmask & FS_DQ_BTIMER)
                dst->i_fieldmask |= QC_SPC_TIMER;
        if (src->d_fieldmask & FS_DQ_ITIMER)
                dst->i_fieldmask |= QC_INO_TIMER;
        if (src->d_fieldmask & FS_DQ_RTBTIMER)
                dst->i_fieldmask |= QC_RT_SPC_TIMER;
}

static int quota_setxquota(struct super_block *sb, int type, qid_t id,
                           void __user *addr)
{
        struct fs_disk_quota fdq;
        struct qc_dqblk qdq;
        struct kqid qid;

        if (copy_from_user(&fdq, addr, sizeof(fdq)))
                return -EFAULT;
        if (!sb->s_qcop->set_dqblk)
                return -ENOSYS;
        qid = make_kqid(current_user_ns(), type, id);
        if (!qid_has_mapping(sb->s_user_ns, qid))
                return -EINVAL;
        /* Are we actually setting timer / warning limits for all users? */
        if (from_kqid(sb->s_user_ns, qid) == 0 &&
            fdq.d_fieldmask & (FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK)) {
                struct qc_info qinfo;
                int ret;

                if (!sb->s_qcop->set_info)
                        return -EINVAL;
                copy_qcinfo_from_xfs_dqblk(&qinfo, &fdq);
                ret = sb->s_qcop->set_info(sb, type, &qinfo);
                if (ret)
                        return ret;
                /* These are already done */
                fdq.d_fieldmask &= ~(FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK);
        }
        copy_from_xfs_dqblk(&qdq, &fdq);
        return sb->s_qcop->set_dqblk(sb, qid, &qdq);
}

static inline void copy_to_xfs_dqblk_ts(const struct fs_disk_quota *d,
                __s32 *timer_lo, __s8 *timer_hi, s64 timer)
{
        *timer_lo = timer;
        if (d->d_fieldmask & FS_DQ_BIGTIME)
                *timer_hi = timer >> 32;
}

static inline bool want_bigtime(s64 timer)
{
        return timer > S32_MAX || timer < S32_MIN;
}

static void copy_to_xfs_dqblk(struct fs_disk_quota *dst, struct qc_dqblk *src,
                              int type, qid_t id)
{
        memset(dst, 0, sizeof(*dst));
        if (want_bigtime(src->d_ino_timer) || want_bigtime(src->d_spc_timer) ||
            want_bigtime(src->d_rt_spc_timer))
                dst->d_fieldmask |= FS_DQ_BIGTIME;
        dst->d_version = FS_DQUOT_VERSION;
        dst->d_id = id;
        if (type == USRQUOTA)
                dst->d_flags = FS_USER_QUOTA;
        else if (type == PRJQUOTA)
                dst->d_flags = FS_PROJ_QUOTA;
        else
                dst->d_flags = FS_GROUP_QUOTA;
        dst->d_blk_hardlimit = quota_btobb(src->d_spc_hardlimit);
        dst->d_blk_softlimit = quota_btobb(src->d_spc_softlimit);
        dst->d_ino_hardlimit = src->d_ino_hardlimit;
        dst->d_ino_softlimit = src->d_ino_softlimit;
        dst->d_bcount = quota_btobb(src->d_space);
        dst->d_icount = src->d_ino_count;
        copy_to_xfs_dqblk_ts(dst, &dst->d_itimer, &dst->d_itimer_hi,
                             src->d_ino_timer);
        copy_to_xfs_dqblk_ts(dst, &dst->d_btimer, &dst->d_btimer_hi,
                             src->d_spc_timer);
        dst->d_iwarns = src->d_ino_warns;
        dst->d_bwarns = src->d_spc_warns;
        dst->d_rtb_hardlimit = quota_btobb(src->d_rt_spc_hardlimit);
        dst->d_rtb_softlimit = quota_btobb(src->d_rt_spc_softlimit);
        dst->d_rtbcount = quota_btobb(src->d_rt_space);
        copy_to_xfs_dqblk_ts(dst, &dst->d_rtbtimer, &dst->d_rtbtimer_hi,
                             src->d_rt_spc_timer);
        dst->d_rtbwarns = src->d_rt_spc_warns;
}

static int quota_getxquota(struct super_block *sb, int type, qid_t id,
                           void __user *addr)
{
        struct fs_disk_quota fdq;
        struct qc_dqblk qdq;
        struct kqid qid;
        int ret;

        if (!sb->s_qcop->get_dqblk)
                return -ENOSYS;
        qid = make_kqid(current_user_ns(), type, id);
        if (!qid_has_mapping(sb->s_user_ns, qid))
                return -EINVAL;
        ret = sb->s_qcop->get_dqblk(sb, qid, &qdq);
        if (ret)
                return ret;
        copy_to_xfs_dqblk(&fdq, &qdq, type, id);
        if (copy_to_user(addr, &fdq, sizeof(fdq)))
                return -EFAULT;
        return ret;
}

/*
 * Return quota for next active quota >= this id, if any exists,
 * otherwise return -ENOENT via ->get_nextdqblk.
 */
static int quota_getnextxquota(struct super_block *sb, int type, qid_t id,
                            void __user *addr)
{
        struct fs_disk_quota fdq;
        struct qc_dqblk qdq;
        struct kqid qid;
        qid_t id_out;
        int ret;

        if (!sb->s_qcop->get_nextdqblk)
                return -ENOSYS;
        qid = make_kqid(current_user_ns(), type, id);
        if (!qid_has_mapping(sb->s_user_ns, qid))
                return -EINVAL;
        ret = sb->s_qcop->get_nextdqblk(sb, &qid, &qdq);
        if (ret)
                return ret;
        id_out = from_kqid(current_user_ns(), qid);
        copy_to_xfs_dqblk(&fdq, &qdq, type, id_out);
        if (copy_to_user(addr, &fdq, sizeof(fdq)))
                return -EFAULT;
        return ret;
}

static int quota_rmxquota(struct super_block *sb, void __user *addr)
{
        __u32 flags;

        if (copy_from_user(&flags, addr, sizeof(flags)))
                return -EFAULT;
        if (!sb->s_qcop->rm_xquota)
                return -ENOSYS;
        return sb->s_qcop->rm_xquota(sb, flags);
}

/* Copy parameters and call proper function */
static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
                       void __user *addr, const struct path *path)
{
        int ret;

        type = array_index_nospec(type, MAXQUOTAS);
        /*
         * Quota not supported on this fs? Check this before s_quota_types
         * since they needn't be set if quota is not supported at all.
         */
        if (!sb->s_qcop)
                return -ENOSYS;
        if (!(sb->s_quota_types & (1 << type)))
                return -EINVAL;

        ret = check_quotactl_permission(sb, type, cmd, id);
        if (ret < 0)
                return ret;

        switch (cmd) {
        case Q_QUOTAON:
                return quota_quotaon(sb, type, id, path);
        case Q_QUOTAOFF:
                return quota_quotaoff(sb, type);
        case Q_GETFMT:
                return quota_getfmt(sb, type, addr);
        case Q_GETINFO:
                return quota_getinfo(sb, type, addr);
        case Q_SETINFO:
                return quota_setinfo(sb, type, addr);
        case Q_GETQUOTA:
                return quota_getquota(sb, type, id, addr);
        case Q_GETNEXTQUOTA:
                return quota_getnextquota(sb, type, id, addr);
        case Q_SETQUOTA:
                return quota_setquota(sb, type, id, addr);
        case Q_SYNC:
                if (!sb->s_qcop->quota_sync)
                        return -ENOSYS;
                return sb->s_qcop->quota_sync(sb, type);
        case Q_XQUOTAON:
                return quota_enable(sb, addr);
        case Q_XQUOTAOFF:
                return quota_disable(sb, addr);
        case Q_XQUOTARM:
                return quota_rmxquota(sb, addr);
        case Q_XGETQSTAT:
                return quota_getxstate(sb, type, addr);
        case Q_XGETQSTATV:
                return quota_getxstatev(sb, type, addr);
        case Q_XSETQLIM:
                return quota_setxquota(sb, type, id, addr);
        case Q_XGETQUOTA:
                return quota_getxquota(sb, type, id, addr);
        case Q_XGETNEXTQUOTA:
                return quota_getnextxquota(sb, type, id, addr);
        case Q_XQUOTASYNC:
                if (sb_rdonly(sb))
                        return -EROFS;
                /* XFS quotas are fully coherent now, making this call a noop */
                return 0;
        default:
                return -EINVAL;
        }
}

/* Return 1 if 'cmd' will block on frozen filesystem */
static int quotactl_cmd_write(int cmd)
{
        /*
         * We cannot allow Q_GETQUOTA and Q_GETNEXTQUOTA without write access
         * as dquot_acquire() may allocate space for new structure and OCFS2
         * needs to increment on-disk use count.
         */
        switch (cmd) {
        case Q_GETFMT:
        case Q_GETINFO:
        case Q_SYNC:
        case Q_XGETQSTAT:
        case Q_XGETQSTATV:
        case Q_XGETQUOTA:
        case Q_XGETNEXTQUOTA:
        case Q_XQUOTASYNC:
                return 0;
        }
        return 1;
}

/* Return true if quotactl command is manipulating quota on/off state */
static bool quotactl_cmd_onoff(int cmd)
{
        return (cmd == Q_QUOTAON) || (cmd == Q_QUOTAOFF) ||
                 (cmd == Q_XQUOTAON) || (cmd == Q_XQUOTAOFF);
}

/*
 * look up a superblock on which quota ops will be performed
 * - use the name of a block device to find the superblock thereon
 */
static struct super_block *quotactl_block(const char __user *special, int cmd)
{
#ifdef CONFIG_BLOCK
        struct super_block *sb;
        CLASS(filename, tmp)(special);
        bool excl = false, thawed = false;
        int error;
        dev_t dev;

        if (IS_ERR(tmp))
                return ERR_CAST(tmp);
        error = lookup_bdev(tmp->name, &dev);
        if (error)
                return ERR_PTR(error);

        if (quotactl_cmd_onoff(cmd)) {
                excl = true;
                thawed = true;
        } else if (quotactl_cmd_write(cmd)) {
                thawed = true;
        }

retry:
        sb = user_get_super(dev, excl);
        if (!sb)
                return ERR_PTR(-ENODEV);
        if (thawed && sb->s_writers.frozen != SB_UNFROZEN) {
                if (excl)
                        up_write(&sb->s_umount);
                else
                        up_read(&sb->s_umount);
                /* Wait for sb to unfreeze */
                sb_start_write(sb);
                sb_end_write(sb);
                put_super(sb);
                cond_resched();
                goto retry;
        }
        return sb;

#else
        return ERR_PTR(-ENODEV);
#endif
}

/*
 * This is the system call interface. This communicates with
 * the user-level programs. Currently this only supports diskquota
 * calls. Maybe we need to add the process quotas etc. in the future,
 * but we probably should use rlimits for that.
 */
SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
                qid_t, id, void __user *, addr)
{
        uint cmds, type;
        struct super_block *sb = NULL;
        struct path path, *pathp = NULL;
        int ret;

        cmds = cmd >> SUBCMDSHIFT;
        type = cmd & SUBCMDMASK;

        if (type >= MAXQUOTAS)
                return -EINVAL;

        /*
         * As a special case Q_SYNC can be called without a specific device.
         * It will iterate all superblocks that have quota enabled and call
         * the sync action on each of them.
         */
        if (!special) {
                if (cmds == Q_SYNC)
                        return quota_sync_all(type);
                return -ENODEV;
        }

        /*
         * Path for quotaon has to be resolved before grabbing superblock
         * because that gets s_umount sem which is also possibly needed by path
         * resolution (think about autofs) and thus deadlocks could arise.
         */
        if (cmds == Q_QUOTAON) {
                ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
                if (ret)
                        pathp = ERR_PTR(ret);
                else
                        pathp = &path;
        }

        sb = quotactl_block(special, cmds);
        if (IS_ERR(sb)) {
                ret = PTR_ERR(sb);
                goto out;
        }

        ret = do_quotactl(sb, type, cmds, id, addr, pathp);

        if (!quotactl_cmd_onoff(cmds))
                drop_super(sb);
        else
                drop_super_exclusive(sb);
out:
        if (pathp && !IS_ERR(pathp))
                path_put(pathp);
        return ret;
}

SYSCALL_DEFINE4(quotactl_fd, unsigned int, fd, unsigned int, cmd,
                qid_t, id, void __user *, addr)
{
        struct super_block *sb;
        unsigned int cmds = cmd >> SUBCMDSHIFT;
        unsigned int type = cmd & SUBCMDMASK;
        CLASS(fd_raw, f)(fd);
        int ret;

        if (fd_empty(f))
                return -EBADF;

        if (type >= MAXQUOTAS)
                return -EINVAL;

        if (quotactl_cmd_write(cmds)) {
                ret = mnt_want_write(fd_file(f)->f_path.mnt);
                if (ret)
                        return ret;
        }

        sb = fd_file(f)->f_path.mnt->mnt_sb;
        if (quotactl_cmd_onoff(cmds))
                down_write(&sb->s_umount);
        else
                down_read(&sb->s_umount);

        ret = do_quotactl(sb, type, cmds, id, addr, ERR_PTR(-EINVAL));

        if (quotactl_cmd_onoff(cmds))
                up_write(&sb->s_umount);
        else
                up_read(&sb->s_umount);

        if (quotactl_cmd_write(cmds))
                mnt_drop_write(fd_file(f)->f_path.mnt);
        return ret;
}