[mirror_ubuntu-zesty-kernel.git] / fs / quota / quota.c

/*
 * 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 if_dqinfo info;
	int ret;

	if (!sb->s_qcop->get_info)
		return -ENOSYS;
	ret = sb->s_qcop->get_info(sb, type, &info);
	if (!ret && copy_to_user(addr, &info, sizeof(info)))
		return -EFAULT;
	return ret;
}

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

	if (copy_from_user(&info, addr, sizeof(info)))
		return -EFAULT;
	if (!sb->s_qcop->set_info)
		return -ENOSYS;
	return sb->s_qcop->set_info(sb, type, &info);
}

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

	if (!sb->s_qcop->get_xstate)
		return -ENOSYS;
	ret = sb->s_qcop->get_xstate(sb, &fqs);
	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
		return -EFAULT;
	return ret;
}

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

	if (!sb->s_qcop->get_xstatev)
		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 = sb->s_qcop->get_xstatev(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 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;
	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;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Quota code necessary even when VFS quota support is not compiled
	3	* into the kernel. The interesting stuff is over in dquot.c, here
	4	* we have symbols for initial quotactl(2) handling, the sysctl(2)
	5	* variables, etc - things needed even when quota support disabled.
	6	*/
	7
	8	#include <linux/fs.h>
	9	#include <linux/namei.h>
	10	#include <linux/slab.h>
	11	#include <asm/current.h>
f3da9310	12	#include <linux/uaccess.h>
1da177e4	13	#include <linux/kernel.h>
1da177e4 LT	14	#include <linux/security.h>
1da177e4 LT	15	#include <linux/syscalls.h>
16f7e0fe	16	#include <linux/capability.h>
be586bab	17	#include <linux/quotaops.h>
b716395e	18	#include <linux/types.h>
8c4e4acd	19	#include <linux/writeback.h>
1da177e4	20
c988afb5 CH	21	static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
c988afb5 CH	22	qid_t id)
1da177e4	23	{
c988afb5 CH	24	switch (cmd) {
	25	/* these commands do not require any special privilegues */
	26	case Q_GETFMT:
	27	case Q_SYNC:
	28	case Q_GETINFO:
	29	case Q_XGETQSTAT:
af30cb44	30	case Q_XGETQSTATV:
c988afb5 CH	31	case Q_XQUOTASYNC:
	32	break;
	33	/* allow to query information for dquots we "own" */
	34	case Q_GETQUOTA:
	35	case Q_XGETQUOTA:
74a8a103 EB	36	if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) \|\|
74a8a103 EB	37	(type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
c988afb5 CH	38	break;
	39	/FALLTHROUGH/
	40	default:
1da177e4 LT	41	if (!capable(CAP_SYS_ADMIN))
	42	return -EPERM;
	43	}
	44
c988afb5	45	return security_quotactl(cmd, type, id, sb);
1da177e4 LT	46	}
1da177e4 LT	47
01a05b33 AV	48	static void quota_sync_one(struct super_block sb, void arg)
01a05b33 AV	49	{
2c5f648a JK	50	int type = (int )arg;
	51
	52	if (sb->s_qcop && sb->s_qcop->quota_sync &&
	53	(sb->s_quota_types & (1 << type)))
	54	sb->s_qcop->quota_sync(sb, type);
01a05b33 AV	55	}
01a05b33 AV	56
6ae09575	57	static int quota_sync_all(int type)
1da177e4	58	{
6ae09575 CH	59	int ret;
	60
	61	if (type >= MAXQUOTAS)
	62	return -EINVAL;
	63	ret = security_quotactl(Q_SYNC, type, 0, NULL);
01a05b33 AV	64	if (!ret)
	65	iterate_supers(quota_sync_one, &type);
	66	return ret;
1da177e4 LT	67	}
1da177e4 LT	68
d3b86324 JK	69	unsigned int qtype_enforce_flag(int type)
	70	{
	71	switch (type) {
	72	case USRQUOTA:
	73	return FS_QUOTA_UDQ_ENFD;
	74	case GRPQUOTA:
	75	return FS_QUOTA_GDQ_ENFD;
	76	case PRJQUOTA:
	77	return FS_QUOTA_PDQ_ENFD;
	78	}
	79	return 0;
	80	}
	81
c411e5f6	82	static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
f00c9e44	83	struct path *path)
1da177e4	84	{
aaa3daed	85	if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_enable)
f00c9e44	86	return -ENOSYS;
d3b86324 JK	87	if (sb->s_qcop->quota_enable)
d3b86324 JK	88	return sb->s_qcop->quota_enable(sb, qtype_enforce_flag(type));
f00c9e44 JK	89	if (IS_ERR(path))
	90	return PTR_ERR(path);
	91	return sb->s_qcop->quota_on(sb, type, id, path);
c411e5f6	92	}
1da177e4	93
d3b86324 JK	94	static int quota_quotaoff(struct super_block *sb, int type)
	95	{
	96	if (!sb->s_qcop->quota_off && !sb->s_qcop->quota_disable)
	97	return -ENOSYS;
	98	if (sb->s_qcop->quota_disable)
	99	return sb->s_qcop->quota_disable(sb, qtype_enforce_flag(type));
	100	return sb->s_qcop->quota_off(sb, type);
	101	}
	102
c411e5f6 CH	103	static int quota_getfmt(struct super_block sb, int type, void __user addr)
	104	{
	105	__u32 fmt;
1da177e4	106
606cdcca	107	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
c411e5f6	108	if (!sb_has_quota_active(sb, type)) {
606cdcca	109	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
c411e5f6 CH	110	return -ESRCH;
	111	}
	112	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
606cdcca	113	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
c411e5f6 CH	114	if (copy_to_user(addr, &fmt, sizeof(fmt)))
	115	return -EFAULT;
	116	return 0;
	117	}
1da177e4	118
c411e5f6 CH	119	static int quota_getinfo(struct super_block sb, int type, void __user addr)
	120	{
	121	struct if_dqinfo info;
	122	int ret;
1da177e4	123
f450d4fe CH	124	if (!sb->s_qcop->get_info)
f450d4fe CH	125	return -ENOSYS;
c411e5f6 CH	126	ret = sb->s_qcop->get_info(sb, type, &info);
	127	if (!ret && copy_to_user(addr, &info, sizeof(info)))
	128	return -EFAULT;
	129	return ret;
	130	}
1da177e4	131
c411e5f6 CH	132	static int quota_setinfo(struct super_block sb, int type, void __user addr)
	133	{
	134	struct if_dqinfo info;
1da177e4	135
c411e5f6 CH	136	if (copy_from_user(&info, addr, sizeof(info)))
c411e5f6 CH	137	return -EFAULT;
f450d4fe CH	138	if (!sb->s_qcop->set_info)
f450d4fe CH	139	return -ENOSYS;
c411e5f6 CH	140	return sb->s_qcop->set_info(sb, type, &info);
	141	}
	142
14bf61ff JK	143	static inline qsize_t qbtos(qsize_t blocks)
	144	{
	145	return blocks << QIF_DQBLKSIZE_BITS;
	146	}
	147
	148	static inline qsize_t stoqb(qsize_t space)
	149	{
	150	return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
	151	}
	152
	153	static void copy_to_if_dqblk(struct if_dqblk dst, struct qc_dqblk src)
b9b2dd36	154	{
18da65e7	155	memset(dst, 0, sizeof(*dst));
14bf61ff JK	156	dst->dqb_bhardlimit = stoqb(src->d_spc_hardlimit);
	157	dst->dqb_bsoftlimit = stoqb(src->d_spc_softlimit);
	158	dst->dqb_curspace = src->d_space;
b9b2dd36 CH	159	dst->dqb_ihardlimit = src->d_ino_hardlimit;
b9b2dd36 CH	160	dst->dqb_isoftlimit = src->d_ino_softlimit;
14bf61ff JK	161	dst->dqb_curinodes = src->d_ino_count;
	162	dst->dqb_btime = src->d_spc_timer;
	163	dst->dqb_itime = src->d_ino_timer;
b9b2dd36 CH	164	dst->dqb_valid = QIF_ALL;
	165	}
	166
c411e5f6 CH	167	static int quota_getquota(struct super_block *sb, int type, qid_t id,
	168	void __user *addr)
	169	{
74a8a103	170	struct kqid qid;
14bf61ff	171	struct qc_dqblk fdq;
c411e5f6 CH	172	struct if_dqblk idq;
	173	int ret;
	174
f450d4fe CH	175	if (!sb->s_qcop->get_dqblk)
f450d4fe CH	176	return -ENOSYS;
74a8a103 EB	177	qid = make_kqid(current_user_ns(), type, id);
	178	if (!qid_valid(qid))
	179	return -EINVAL;
	180	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
c411e5f6 CH	181	if (ret)
c411e5f6 CH	182	return ret;
b9b2dd36	183	copy_to_if_dqblk(&idq, &fdq);
c411e5f6 CH	184	if (copy_to_user(addr, &idq, sizeof(idq)))
	185	return -EFAULT;
	186	return 0;
	187	}
	188
14bf61ff	189	static void copy_from_if_dqblk(struct qc_dqblk dst, struct if_dqblk src)
c472b432	190	{
14bf61ff JK	191	dst->d_spc_hardlimit = qbtos(src->dqb_bhardlimit);
	192	dst->d_spc_softlimit = qbtos(src->dqb_bsoftlimit);
	193	dst->d_space = src->dqb_curspace;
c472b432 CH	194	dst->d_ino_hardlimit = src->dqb_ihardlimit;
c472b432 CH	195	dst->d_ino_softlimit = src->dqb_isoftlimit;
14bf61ff JK	196	dst->d_ino_count = src->dqb_curinodes;
	197	dst->d_spc_timer = src->dqb_btime;
	198	dst->d_ino_timer = src->dqb_itime;
c472b432 CH	199
	200	dst->d_fieldmask = 0;
	201	if (src->dqb_valid & QIF_BLIMITS)
14bf61ff	202	dst->d_fieldmask \|= QC_SPC_SOFT \| QC_SPC_HARD;
c472b432	203	if (src->dqb_valid & QIF_SPACE)
14bf61ff	204	dst->d_fieldmask \|= QC_SPACE;
c472b432	205	if (src->dqb_valid & QIF_ILIMITS)
14bf61ff	206	dst->d_fieldmask \|= QC_INO_SOFT \| QC_INO_HARD;
c472b432	207	if (src->dqb_valid & QIF_INODES)
14bf61ff	208	dst->d_fieldmask \|= QC_INO_COUNT;
c472b432	209	if (src->dqb_valid & QIF_BTIME)
14bf61ff	210	dst->d_fieldmask \|= QC_SPC_TIMER;
c472b432	211	if (src->dqb_valid & QIF_ITIME)
14bf61ff	212	dst->d_fieldmask \|= QC_INO_TIMER;
c472b432 CH	213	}
c472b432 CH	214
c411e5f6 CH	215	static int quota_setquota(struct super_block *sb, int type, qid_t id,
	216	void __user *addr)
	217	{
14bf61ff	218	struct qc_dqblk fdq;
c411e5f6	219	struct if_dqblk idq;
74a8a103	220	struct kqid qid;
c411e5f6 CH	221
	222	if (copy_from_user(&idq, addr, sizeof(idq)))
	223	return -EFAULT;
f450d4fe CH	224	if (!sb->s_qcop->set_dqblk)
f450d4fe CH	225	return -ENOSYS;
74a8a103 EB	226	qid = make_kqid(current_user_ns(), type, id);
	227	if (!qid_valid(qid))
	228	return -EINVAL;
c472b432	229	copy_from_if_dqblk(&fdq, &idq);
74a8a103	230	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
c411e5f6 CH	231	}
c411e5f6 CH	232
38e478c4	233	static int quota_enable(struct super_block sb, void __user addr)
c411e5f6 CH	234	{
	235	__u32 flags;
	236
	237	if (copy_from_user(&flags, addr, sizeof(flags)))
	238	return -EFAULT;
38e478c4	239	if (!sb->s_qcop->quota_enable)
f450d4fe	240	return -ENOSYS;
38e478c4 JK	241	return sb->s_qcop->quota_enable(sb, flags);
	242	}
	243
	244	static int quota_disable(struct super_block sb, void __user addr)
	245	{
	246	__u32 flags;
	247
	248	if (copy_from_user(&flags, addr, sizeof(flags)))
	249	return -EFAULT;
	250	if (!sb->s_qcop->quota_disable)
	251	return -ENOSYS;
	252	return sb->s_qcop->quota_disable(sb, flags);
c411e5f6 CH	253	}
	254
	255	static int quota_getxstate(struct super_block sb, void __user addr)
	256	{
	257	struct fs_quota_stat fqs;
	258	int ret;
f450d4fe CH	259
	260	if (!sb->s_qcop->get_xstate)
	261	return -ENOSYS;
c411e5f6 CH	262	ret = sb->s_qcop->get_xstate(sb, &fqs);
	263	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
	264	return -EFAULT;
	265	return ret;
	266	}
1da177e4	267
af30cb44 CS	268	static int quota_getxstatev(struct super_block sb, void __user addr)
	269	{
	270	struct fs_quota_statv fqs;
	271	int ret;
	272
	273	if (!sb->s_qcop->get_xstatev)
	274	return -ENOSYS;
	275
	276	memset(&fqs, 0, sizeof(fqs));
	277	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
	278	return -EFAULT;
	279
	280	/* If this kernel doesn't support user specified version, fail */
	281	switch (fqs.qs_version) {
	282	case FS_QSTATV_VERSION1:
	283	break;
	284	default:
	285	return -EINVAL;
	286	}
	287	ret = sb->s_qcop->get_xstatev(sb, &fqs);
	288	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
	289	return -EFAULT;
	290	return ret;
	291	}
	292
14bf61ff JK	293	/*
	294	* XFS defines BBTOB and BTOBB macros inside fs/xfs/ and we cannot move them
	295	* out of there as xfsprogs rely on definitions being in that header file. So
	296	* just define same functions here for quota purposes.
	297	*/
	298	#define XFS_BB_SHIFT 9
	299
	300	static inline u64 quota_bbtob(u64 blocks)
	301	{
	302	return blocks << XFS_BB_SHIFT;
	303	}
	304
	305	static inline u64 quota_btobb(u64 bytes)
	306	{
	307	return (bytes + (1 << XFS_BB_SHIFT) - 1) >> XFS_BB_SHIFT;
	308	}
	309
	310	static void copy_from_xfs_dqblk(struct qc_dqblk dst, struct fs_disk_quota src)
	311	{
	312	dst->d_spc_hardlimit = quota_bbtob(src->d_blk_hardlimit);
	313	dst->d_spc_softlimit = quota_bbtob(src->d_blk_softlimit);
	314	dst->d_ino_hardlimit = src->d_ino_hardlimit;
	315	dst->d_ino_softlimit = src->d_ino_softlimit;
	316	dst->d_space = quota_bbtob(src->d_bcount);
	317	dst->d_ino_count = src->d_icount;
	318	dst->d_ino_timer = src->d_itimer;
	319	dst->d_spc_timer = src->d_btimer;
	320	dst->d_ino_warns = src->d_iwarns;
	321	dst->d_spc_warns = src->d_bwarns;
	322	dst->d_rt_spc_hardlimit = quota_bbtob(src->d_rtb_hardlimit);
	323	dst->d_rt_spc_softlimit = quota_bbtob(src->d_rtb_softlimit);
	324	dst->d_rt_space = quota_bbtob(src->d_rtbcount);
	325	dst->d_rt_spc_timer = src->d_rtbtimer;
	326	dst->d_rt_spc_warns = src->d_rtbwarns;
	327	dst->d_fieldmask = 0;
	328	if (src->d_fieldmask & FS_DQ_ISOFT)
	329	dst->d_fieldmask \|= QC_INO_SOFT;
	330	if (src->d_fieldmask & FS_DQ_IHARD)
	331	dst->d_fieldmask \|= QC_INO_HARD;
	332	if (src->d_fieldmask & FS_DQ_BSOFT)
	333	dst->d_fieldmask \|= QC_SPC_SOFT;
	334	if (src->d_fieldmask & FS_DQ_BHARD)
	335	dst->d_fieldmask \|= QC_SPC_HARD;
	336	if (src->d_fieldmask & FS_DQ_RTBSOFT)
	337	dst->d_fieldmask \|= QC_RT_SPC_SOFT;
	338	if (src->d_fieldmask & FS_DQ_RTBHARD)
	339	dst->d_fieldmask \|= QC_RT_SPC_HARD;
	340	if (src->d_fieldmask & FS_DQ_BTIMER)
	341	dst->d_fieldmask \|= QC_SPC_TIMER;
	342	if (src->d_fieldmask & FS_DQ_ITIMER)
	343	dst->d_fieldmask \|= QC_INO_TIMER;
	344	if (src->d_fieldmask & FS_DQ_RTBTIMER)
	345	dst->d_fieldmask \|= QC_RT_SPC_TIMER;
	346	if (src->d_fieldmask & FS_DQ_BWARNS)
	347	dst->d_fieldmask \|= QC_SPC_WARNS;
	348	if (src->d_fieldmask & FS_DQ_IWARNS)
	349	dst->d_fieldmask \|= QC_INO_WARNS;
	350	if (src->d_fieldmask & FS_DQ_RTBWARNS)
	351	dst->d_fieldmask \|= QC_RT_SPC_WARNS;
	352	if (src->d_fieldmask & FS_DQ_BCOUNT)
	353	dst->d_fieldmask \|= QC_SPACE;
	354	if (src->d_fieldmask & FS_DQ_ICOUNT)
	355	dst->d_fieldmask \|= QC_INO_COUNT;
	356	if (src->d_fieldmask & FS_DQ_RTBCOUNT)
357	dst->d_fieldmask \|= QC_RT_SPACE;
358	}
359
c411e5f6 CH	360	static int quota_setxquota(struct super_block *sb, int type, qid_t id,
	361	void __user *addr)
	362	{
	363	struct fs_disk_quota fdq;
14bf61ff	364	struct qc_dqblk qdq;
74a8a103	365	struct kqid qid;
c411e5f6 CH	366
	367	if (copy_from_user(&fdq, addr, sizeof(fdq)))
	368	return -EFAULT;
c472b432	369	if (!sb->s_qcop->set_dqblk)
f450d4fe	370	return -ENOSYS;
74a8a103 EB	371	qid = make_kqid(current_user_ns(), type, id);
	372	if (!qid_valid(qid))
	373	return -EINVAL;
14bf61ff JK	374	copy_from_xfs_dqblk(&qdq, &fdq);
	375	return sb->s_qcop->set_dqblk(sb, qid, &qdq);
	376	}
	377
	378	static void copy_to_xfs_dqblk(struct fs_disk_quota dst, struct qc_dqblk src,
	379	int type, qid_t id)
	380	{
	381	memset(dst, 0, sizeof(*dst));
	382	dst->d_version = FS_DQUOT_VERSION;
	383	dst->d_id = id;
	384	if (type == USRQUOTA)
	385	dst->d_flags = FS_USER_QUOTA;
	386	else if (type == PRJQUOTA)
	387	dst->d_flags = FS_PROJ_QUOTA;
	388	else
	389	dst->d_flags = FS_GROUP_QUOTA;
	390	dst->d_blk_hardlimit = quota_btobb(src->d_spc_hardlimit);
	391	dst->d_blk_softlimit = quota_btobb(src->d_spc_softlimit);
	392	dst->d_ino_hardlimit = src->d_ino_hardlimit;
	393	dst->d_ino_softlimit = src->d_ino_softlimit;
	394	dst->d_bcount = quota_btobb(src->d_space);
	395	dst->d_icount = src->d_ino_count;
	396	dst->d_itimer = src->d_ino_timer;
	397	dst->d_btimer = src->d_spc_timer;
	398	dst->d_iwarns = src->d_ino_warns;
	399	dst->d_bwarns = src->d_spc_warns;
	400	dst->d_rtb_hardlimit = quota_btobb(src->d_rt_spc_hardlimit);
	401	dst->d_rtb_softlimit = quota_btobb(src->d_rt_spc_softlimit);
	402	dst->d_rtbcount = quota_btobb(src->d_rt_space);
	403	dst->d_rtbtimer = src->d_rt_spc_timer;
	404	dst->d_rtbwarns = src->d_rt_spc_warns;
c411e5f6 CH	405	}
	406
	407	static int quota_getxquota(struct super_block *sb, int type, qid_t id,
	408	void __user *addr)
	409	{
	410	struct fs_disk_quota fdq;
14bf61ff	411	struct qc_dqblk qdq;
74a8a103	412	struct kqid qid;
c411e5f6 CH	413	int ret;
c411e5f6 CH	414
b9b2dd36	415	if (!sb->s_qcop->get_dqblk)
f450d4fe	416	return -ENOSYS;
74a8a103 EB	417	qid = make_kqid(current_user_ns(), type, id);
	418	if (!qid_valid(qid))
	419	return -EINVAL;
14bf61ff JK	420	ret = sb->s_qcop->get_dqblk(sb, qid, &qdq);
	421	if (ret)
	422	return ret;
	423	copy_to_xfs_dqblk(&fdq, &qdq, type, id);
	424	if (copy_to_user(addr, &fdq, sizeof(fdq)))
c411e5f6 CH	425	return -EFAULT;
	426	return ret;
	427	}
	428
9da93f9b ES	429	static int quota_rmxquota(struct super_block sb, void __user addr)
	430	{
	431	__u32 flags;
	432
	433	if (copy_from_user(&flags, addr, sizeof(flags)))
	434	return -EFAULT;
	435	if (!sb->s_qcop->rm_xquota)
	436	return -ENOSYS;
	437	return sb->s_qcop->rm_xquota(sb, flags);
	438	}
	439
c411e5f6 CH	440	/* Copy parameters and call proper function */
c411e5f6 CH	441	static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
f00c9e44	442	void __user addr, struct path path)
c411e5f6	443	{
c988afb5 CH	444	int ret;
	445
	446	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
	447	return -EINVAL;
2c5f648a JK	448	/*
	449	* Quota not supported on this fs? Check this before s_quota_types
	450	* since they needn't be set if quota is not supported at all.
	451	*/
c988afb5 CH	452	if (!sb->s_qcop)
c988afb5 CH	453	return -ENOSYS;
2c5f648a JK	454	if (!(sb->s_quota_types & (1 << type)))
2c5f648a JK	455	return -EINVAL;
c988afb5 CH	456
	457	ret = check_quotactl_permission(sb, type, cmd, id);
	458	if (ret < 0)
	459	return ret;
	460
c411e5f6 CH	461	switch (cmd) {
c411e5f6 CH	462	case Q_QUOTAON:
f00c9e44	463	return quota_quotaon(sb, type, cmd, id, path);
c411e5f6	464	case Q_QUOTAOFF:
d3b86324	465	return quota_quotaoff(sb, type);
c411e5f6 CH	466	case Q_GETFMT:
	467	return quota_getfmt(sb, type, addr);
	468	case Q_GETINFO:
	469	return quota_getinfo(sb, type, addr);
	470	case Q_SETINFO:
	471	return quota_setinfo(sb, type, addr);
	472	case Q_GETQUOTA:
	473	return quota_getquota(sb, type, id, addr);
	474	case Q_SETQUOTA:
	475	return quota_setquota(sb, type, id, addr);
	476	case Q_SYNC:
6ae09575 CH	477	if (!sb->s_qcop->quota_sync)
6ae09575 CH	478	return -ENOSYS;
ceed1723	479	return sb->s_qcop->quota_sync(sb, type);
c411e5f6	480	case Q_XQUOTAON:
38e478c4	481	return quota_enable(sb, addr);
c411e5f6	482	case Q_XQUOTAOFF:
38e478c4	483	return quota_disable(sb, addr);
9da93f9b ES	484	case Q_XQUOTARM:
9da93f9b ES	485	return quota_rmxquota(sb, addr);
c411e5f6 CH	486	case Q_XGETQSTAT:
c411e5f6 CH	487	return quota_getxstate(sb, addr);
af30cb44 CS	488	case Q_XGETQSTATV:
af30cb44 CS	489	return quota_getxstatev(sb, addr);
c411e5f6 CH	490	case Q_XSETQLIM:
	491	return quota_setxquota(sb, type, id, addr);
	492	case Q_XGETQUOTA:
	493	return quota_getxquota(sb, type, id, addr);
	494	case Q_XQUOTASYNC:
8c4e4acd CH	495	if (sb->s_flags & MS_RDONLY)
8c4e4acd CH	496	return -EROFS;
4b217ed9	497	/* XFS quotas are fully coherent now, making this call a noop */
8c4e4acd	498	return 0;
c411e5f6	499	default:
f450d4fe	500	return -EINVAL;
1da177e4	501	}
1da177e4 LT	502	}
1da177e4 LT	503
56df1278 LJ	504	#ifdef CONFIG_BLOCK
56df1278 LJ	505
dcdbed85 JK	506	/* Return 1 if 'cmd' will block on frozen filesystem */
	507	static int quotactl_cmd_write(int cmd)
	508	{
	509	switch (cmd) {
	510	case Q_GETFMT:
	511	case Q_GETINFO:
	512	case Q_SYNC:
	513	case Q_XGETQSTAT:
af30cb44	514	case Q_XGETQSTATV:
dcdbed85 JK	515	case Q_XGETQUOTA:
	516	case Q_XQUOTASYNC:
	517	return 0;
	518	}
	519	return 1;
	520	}
	521
56df1278 LJ	522	#endif /* CONFIG_BLOCK */
56df1278 LJ	523
9361401e DH	524	/*
	525	* look up a superblock on which quota ops will be performed
	526	* - use the name of a block device to find the superblock thereon
	527	*/
dcdbed85	528	static struct super_block quotactl_block(const char __user special, int cmd)
9361401e DH	529	{
	530	#ifdef CONFIG_BLOCK
	531	struct block_device *bdev;
	532	struct super_block *sb;
91a27b2a	533	struct filename *tmp = getname(special);
9361401e DH	534
9361401e DH	535	if (IS_ERR(tmp))
e231c2ee	536	return ERR_CAST(tmp);
91a27b2a	537	bdev = lookup_bdev(tmp->name);
9361401e DH	538	putname(tmp);
9361401e DH	539	if (IS_ERR(bdev))
e231c2ee	540	return ERR_CAST(bdev);
dcdbed85 JK	541	if (quotactl_cmd_write(cmd))
	542	sb = get_super_thawed(bdev);
	543	else
	544	sb = get_super(bdev);
9361401e DH	545	bdput(bdev);
	546	if (!sb)
	547	return ERR_PTR(-ENODEV);
	548
	549	return sb;
	550	#else
	551	return ERR_PTR(-ENODEV);
	552	#endif
	553	}
	554
1da177e4 LT	555	/*
	556	* This is the system call interface. This communicates with
	557	* the user-level programs. Currently this only supports diskquota
	558	* calls. Maybe we need to add the process quotas etc. in the future,
	559	* but we probably should use rlimits for that.
	560	*/
3cdad428 HC	561	SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
3cdad428 HC	562	qid_t, id, void __user *, addr)
1da177e4 LT	563	{
	564	uint cmds, type;
	565	struct super_block *sb = NULL;
f00c9e44	566	struct path path, *pathp = NULL;
1da177e4 LT	567	int ret;
	568
	569	cmds = cmd >> SUBCMDSHIFT;
	570	type = cmd & SUBCMDMASK;
	571
6ae09575 CH	572	/*
	573	* As a special case Q_SYNC can be called without a specific device.
	574	* It will iterate all superblocks that have quota enabled and call
	575	* the sync action on each of them.
	576	*/
	577	if (!special) {
	578	if (cmds == Q_SYNC)
	579	return quota_sync_all(type);
	580	return -ENODEV;
1da177e4 LT	581	}
1da177e4 LT	582
f00c9e44 JK	583	/*
	584	* Path for quotaon has to be resolved before grabbing superblock
	585	* because that gets s_umount sem which is also possibly needed by path
	586	* resolution (think about autofs) and thus deadlocks could arise.
	587	*/
	588	if (cmds == Q_QUOTAON) {
815d405c	589	ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW\|LOOKUP_AUTOMOUNT, &path);
f00c9e44 JK	590	if (ret)
	591	pathp = ERR_PTR(ret);
	592	else
	593	pathp = &path;
	594	}
	595
dcdbed85	596	sb = quotactl_block(special, cmds);
0aaa6188 JK	597	if (IS_ERR(sb)) {
	598	ret = PTR_ERR(sb);
	599	goto out;
	600	}
6ae09575	601
f00c9e44	602	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
1da177e4	603
6ae09575	604	drop_super(sb);
0aaa6188	605	out:
f00c9e44 JK	606	if (pathp && !IS_ERR(pathp))
f00c9e44 JK	607	path_put(pathp);
1da177e4 LT	608	return ret;
1da177e4 LT	609	}