Initial import

1 files changed, 808 insertions, 0 deletions

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
new file mode 100644
index 000000000..86ded7375
--- /dev/null
+++ b/fs/quota/quota.c
@@ -0,0 +1,808 @@
+/*
+ * 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/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/writeback.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;
+
+	if (type >= MAXQUOTAS)
+		return -EINVAL;
+	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, int cmd, qid_t id,
+		         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;
+
+	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
+	if (!sb_has_quota_active(sb, type)) {
+		mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
+		return -ESRCH;
+	}
+	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
+	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
+	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;
+
+	/* This checks whether qc_state has enough entries... */
+	BUILD_BUG_ON(MAXQUOTAS > XQM_MAXQUOTAS);
+	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 (!ret && copy_to_user(addr, &uinfo, sizeof(uinfo)))
+		return -EFAULT;
+	return ret;
+}
+
+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_valid(qid))
+		return -EINVAL;
+	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
+	if (ret)
+		return ret;
+	copy_to_if_dqblk(&idq, &fdq);
+	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 (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_valid(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, struct fs_quota_stat *fqs)
+{
+	int type;
+	struct qc_state state;
+	int ret;
+
+	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;
+	/*
+	 * GETXSTATE quotactl has space for just one set of time limits so
+	 * report them for the first enabled quota type
+	 */
+	for (type = 0; type < XQM_MAXQUOTAS; type++)
+		if (state.s_state[type].flags & QCI_ACCT_ENABLED)
+			break;
+	BUG_ON(type == XQM_MAXQUOTAS);
+	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;
+	if (state.s_state[USRQUOTA].flags & QCI_ACCT_ENABLED) {
+		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].flags & QCI_ACCT_ENABLED) {
+		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].flags & QCI_ACCT_ENABLED) {
+		/*
+		 * 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 quota_getxstate(struct super_block *sb, void __user *addr)
+{
+	struct fs_quota_stat fqs;
+	int ret;
+
+	if (!sb->s_qcop->get_state)
+		return -ENOSYS;
+	ret = quota_getstate(sb, &fqs);
+	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
+		return -EFAULT;
+	return ret;
+}
+
+static int quota_getstatev(struct super_block *sb, struct fs_quota_statv *fqs)
+{
+	int type;
+	struct qc_state state;
+	int ret;
+
+	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;
+	/*
+	 * GETXSTATV quotactl has space for just one set of time limits so
+	 * report them for the first enabled quota type
+	 */
+	for (type = 0; type < XQM_MAXQUOTAS; type++)
+		if (state.s_state[type].flags & QCI_ACCT_ENABLED)
+			break;
+	BUG_ON(type == XQM_MAXQUOTAS);
+	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;
+	if (state.s_state[USRQUOTA].flags & QCI_ACCT_ENABLED) {
+		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].flags & QCI_ACCT_ENABLED) {
+		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].flags & QCI_ACCT_ENABLED) {
+		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, 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, &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 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 = src->d_itimer;
+	dst->d_spc_timer = src->d_btimer;
+	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 = src->d_rtbtimer;
+	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_valid(qid))
+		return -EINVAL;
+	/* Are we actually setting timer / warning limits for all users? */
+	if (from_kqid(&init_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 void copy_to_xfs_dqblk(struct fs_disk_quota *dst, struct qc_dqblk *src,
+			      int type, qid_t id)
+{
+	memset(dst, 0, sizeof(*dst));
+	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;
+	dst->d_itimer = src->d_ino_timer;
+	dst->d_btimer = 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);
+	dst->d_rtbtimer = 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_valid(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;
+}
+
+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, struct path *path)
+{
+	int ret;
+
+	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
+		return -EINVAL;
+	/*
+	 * 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, cmd, 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_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, addr);
+	case Q_XGETQSTATV:
+		return quota_getxstatev(sb, addr);
+	case Q_XSETQLIM:
+		return quota_setxquota(sb, type, id, addr);
+	case Q_XGETQUOTA:
+		return quota_getxquota(sb, type, id, addr);
+	case Q_XQUOTASYNC:
+		if (sb->s_flags & MS_RDONLY)
+			return -EROFS;
+		/* XFS quotas are fully coherent now, making this call a noop */
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+#ifdef CONFIG_BLOCK
+
+/* Return 1 if 'cmd' will block on frozen filesystem */
+static int quotactl_cmd_write(int cmd)
+{
+	switch (cmd) {
+	case Q_GETFMT:
+	case Q_GETINFO:
+	case Q_SYNC:
+	case Q_XGETQSTAT:
+	case Q_XGETQSTATV:
+	case Q_XGETQUOTA:
+	case Q_XQUOTASYNC:
+		return 0;
+	}
+	return 1;
+}
+
+#endif /* CONFIG_BLOCK */
+
+/*
+ * 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 block_device *bdev;
+	struct super_block *sb;
+	struct filename *tmp = getname(special);
+
+	if (IS_ERR(tmp))
+		return ERR_CAST(tmp);
+	bdev = lookup_bdev(tmp->name);
+	putname(tmp);
+	if (IS_ERR(bdev))
+		return ERR_CAST(bdev);
+	if (quotactl_cmd_write(cmd))
+		sb = get_super_thawed(bdev);
+	else
+		sb = get_super(bdev);
+	bdput(bdev);
+	if (!sb)
+		return ERR_PTR(-ENODEV);
+
+	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;
+
+	/*
+	 * 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);
+
+	drop_super(sb);
+out:
+	if (pathp && !IS_ERR(pathp))
+		path_put(pathp);
+	return ret;
+}