[deliverable/linux.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)
{
	if (sb->s_qcop && sb->s_qcop->quota_sync)
		sb->s_qcop->quota_sync(sb, *(int *)arg);
}

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;
}

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_on_meta)
		return -ENOSYS;
	if (sb->s_qcop->quota_on_meta)
		return sb->s_qcop->quota_on_meta(sb, type, id);
	if (IS_ERR(path))
		return PTR_ERR(path);
	return sb->s_qcop->quota_on(sb, type, id, path);
}

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

	down_read(&sb_dqopt(sb)->dqptr_sem);
	if (!sb_has_quota_active(sb, type)) {
		up_read(&sb_dqopt(sb)->dqptr_sem);
		return -ESRCH;
	}
	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
	up_read(&sb_dqopt(sb)->dqptr_sem);
	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 void copy_to_if_dqblk(struct if_dqblk *dst, struct fs_disk_quota *src)
{
	dst->dqb_bhardlimit = src->d_blk_hardlimit;
	dst->dqb_bsoftlimit = src->d_blk_softlimit;
	dst->dqb_curspace = src->d_bcount;
	dst->dqb_ihardlimit = src->d_ino_hardlimit;
	dst->dqb_isoftlimit = src->d_ino_softlimit;
	dst->dqb_curinodes = src->d_icount;
	dst->dqb_btime = src->d_btimer;
	dst->dqb_itime = src->d_itimer;
	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 fs_disk_quota 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 fs_disk_quota *dst, struct if_dqblk *src)
{
	dst->d_blk_hardlimit = src->dqb_bhardlimit;
	dst->d_blk_softlimit  = src->dqb_bsoftlimit;
	dst->d_bcount = src->dqb_curspace;
	dst->d_ino_hardlimit = src->dqb_ihardlimit;
	dst->d_ino_softlimit = src->dqb_isoftlimit;
	dst->d_icount = src->dqb_curinodes;
	dst->d_btimer = src->dqb_btime;
	dst->d_itimer = src->dqb_itime;

	dst->d_fieldmask = 0;
	if (src->dqb_valid & QIF_BLIMITS)
		dst->d_fieldmask |= FS_DQ_BSOFT | FS_DQ_BHARD;
	if (src->dqb_valid & QIF_SPACE)
		dst->d_fieldmask |= FS_DQ_BCOUNT;
	if (src->dqb_valid & QIF_ILIMITS)
		dst->d_fieldmask |= FS_DQ_ISOFT | FS_DQ_IHARD;
	if (src->dqb_valid & QIF_INODES)
		dst->d_fieldmask |= FS_DQ_ICOUNT;
	if (src->dqb_valid & QIF_BTIME)
		dst->d_fieldmask |= FS_DQ_BTIMER;
	if (src->dqb_valid & QIF_ITIME)
		dst->d_fieldmask |= FS_DQ_ITIMER;
}

static int quota_setquota(struct super_block *sb, int type, qid_t id,
			  void __user *addr)
{
	struct fs_disk_quota 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_setxstate(struct super_block *sb, int cmd, void __user *addr)
{
	__u32 flags;

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

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;
}

static int quota_setxquota(struct super_block *sb, int type, qid_t id,
			   void __user *addr)
{
	struct fs_disk_quota fdq;
	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;
	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
}

static int quota_getxquota(struct super_block *sb, int type, qid_t id,
			   void __user *addr)
{
	struct fs_disk_quota fdq;
	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, &fdq);
	if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
		return -EFAULT;
	return ret;
}

/* 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;
	if (!sb->s_qcop)
		return -ENOSYS;

	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:
		if (!sb->s_qcop->quota_off)
			return -ENOSYS;
		return sb->s_qcop->quota_off(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:
	case Q_XQUOTAOFF:
	case Q_XQUOTARM:
		return quota_setxstate(sb, cmd, 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)
	49	{
	50	if (sb->s_qcop && sb->s_qcop->quota_sync)
ceed1723	51	sb->s_qcop->quota_sync(sb, (int )arg);
01a05b33 AV	52	}
01a05b33 AV	53
6ae09575	54	static int quota_sync_all(int type)
1da177e4	55	{
6ae09575 CH	56	int ret;
	57
	58	if (type >= MAXQUOTAS)
	59	return -EINVAL;
	60	ret = security_quotactl(Q_SYNC, type, 0, NULL);
01a05b33 AV	61	if (!ret)
	62	iterate_supers(quota_sync_one, &type);
	63	return ret;
1da177e4 LT	64	}
1da177e4 LT	65
c411e5f6	66	static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
f00c9e44	67	struct path *path)
1da177e4	68	{
f00c9e44 JK	69	if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_on_meta)
	70	return -ENOSYS;
	71	if (sb->s_qcop->quota_on_meta)
	72	return sb->s_qcop->quota_on_meta(sb, type, id);
	73	if (IS_ERR(path))
	74	return PTR_ERR(path);
	75	return sb->s_qcop->quota_on(sb, type, id, path);
c411e5f6	76	}
1da177e4	77
c411e5f6 CH	78	static int quota_getfmt(struct super_block sb, int type, void __user addr)
	79	{
	80	__u32 fmt;
1da177e4	81
c411e5f6 CH	82	down_read(&sb_dqopt(sb)->dqptr_sem);
	83	if (!sb_has_quota_active(sb, type)) {
	84	up_read(&sb_dqopt(sb)->dqptr_sem);
	85	return -ESRCH;
	86	}
	87	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
	88	up_read(&sb_dqopt(sb)->dqptr_sem);
	89	if (copy_to_user(addr, &fmt, sizeof(fmt)))
	90	return -EFAULT;
	91	return 0;
	92	}
1da177e4	93
c411e5f6 CH	94	static int quota_getinfo(struct super_block sb, int type, void __user addr)
	95	{
	96	struct if_dqinfo info;
	97	int ret;
1da177e4	98
f450d4fe CH	99	if (!sb->s_qcop->get_info)
f450d4fe CH	100	return -ENOSYS;
c411e5f6 CH	101	ret = sb->s_qcop->get_info(sb, type, &info);
	102	if (!ret && copy_to_user(addr, &info, sizeof(info)))
	103	return -EFAULT;
	104	return ret;
	105	}
1da177e4	106
c411e5f6 CH	107	static int quota_setinfo(struct super_block sb, int type, void __user addr)
	108	{
	109	struct if_dqinfo info;
1da177e4	110
c411e5f6 CH	111	if (copy_from_user(&info, addr, sizeof(info)))
c411e5f6 CH	112	return -EFAULT;
f450d4fe CH	113	if (!sb->s_qcop->set_info)
f450d4fe CH	114	return -ENOSYS;
c411e5f6 CH	115	return sb->s_qcop->set_info(sb, type, &info);
	116	}
	117
b9b2dd36 CH	118	static void copy_to_if_dqblk(struct if_dqblk dst, struct fs_disk_quota src)
	119	{
	120	dst->dqb_bhardlimit = src->d_blk_hardlimit;
	121	dst->dqb_bsoftlimit = src->d_blk_softlimit;
	122	dst->dqb_curspace = src->d_bcount;
	123	dst->dqb_ihardlimit = src->d_ino_hardlimit;
	124	dst->dqb_isoftlimit = src->d_ino_softlimit;
	125	dst->dqb_curinodes = src->d_icount;
	126	dst->dqb_btime = src->d_btimer;
	127	dst->dqb_itime = src->d_itimer;
	128	dst->dqb_valid = QIF_ALL;
	129	}
	130
c411e5f6 CH	131	static int quota_getquota(struct super_block *sb, int type, qid_t id,
	132	void __user *addr)
	133	{
74a8a103	134	struct kqid qid;
b9b2dd36	135	struct fs_disk_quota fdq;
c411e5f6 CH	136	struct if_dqblk idq;
	137	int ret;
	138
f450d4fe CH	139	if (!sb->s_qcop->get_dqblk)
f450d4fe CH	140	return -ENOSYS;
74a8a103 EB	141	qid = make_kqid(current_user_ns(), type, id);
	142	if (!qid_valid(qid))
	143	return -EINVAL;
	144	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
c411e5f6 CH	145	if (ret)
c411e5f6 CH	146	return ret;
b9b2dd36	147	copy_to_if_dqblk(&idq, &fdq);
c411e5f6 CH	148	if (copy_to_user(addr, &idq, sizeof(idq)))
	149	return -EFAULT;
	150	return 0;
	151	}
	152
c472b432 CH	153	static void copy_from_if_dqblk(struct fs_disk_quota dst, struct if_dqblk src)
	154	{
	155	dst->d_blk_hardlimit = src->dqb_bhardlimit;
	156	dst->d_blk_softlimit = src->dqb_bsoftlimit;
	157	dst->d_bcount = src->dqb_curspace;
	158	dst->d_ino_hardlimit = src->dqb_ihardlimit;
	159	dst->d_ino_softlimit = src->dqb_isoftlimit;
	160	dst->d_icount = src->dqb_curinodes;
	161	dst->d_btimer = src->dqb_btime;
	162	dst->d_itimer = src->dqb_itime;
	163
	164	dst->d_fieldmask = 0;
	165	if (src->dqb_valid & QIF_BLIMITS)
	166	dst->d_fieldmask \|= FS_DQ_BSOFT \| FS_DQ_BHARD;
	167	if (src->dqb_valid & QIF_SPACE)
	168	dst->d_fieldmask \|= FS_DQ_BCOUNT;
	169	if (src->dqb_valid & QIF_ILIMITS)
	170	dst->d_fieldmask \|= FS_DQ_ISOFT \| FS_DQ_IHARD;
	171	if (src->dqb_valid & QIF_INODES)
	172	dst->d_fieldmask \|= FS_DQ_ICOUNT;
	173	if (src->dqb_valid & QIF_BTIME)
	174	dst->d_fieldmask \|= FS_DQ_BTIMER;
	175	if (src->dqb_valid & QIF_ITIME)
	176	dst->d_fieldmask \|= FS_DQ_ITIMER;
	177	}
	178
c411e5f6 CH	179	static int quota_setquota(struct super_block *sb, int type, qid_t id,
	180	void __user *addr)
	181	{
c472b432	182	struct fs_disk_quota fdq;
c411e5f6	183	struct if_dqblk idq;
74a8a103	184	struct kqid qid;
c411e5f6 CH	185
	186	if (copy_from_user(&idq, addr, sizeof(idq)))
	187	return -EFAULT;
f450d4fe CH	188	if (!sb->s_qcop->set_dqblk)
f450d4fe CH	189	return -ENOSYS;
74a8a103 EB	190	qid = make_kqid(current_user_ns(), type, id);
	191	if (!qid_valid(qid))
	192	return -EINVAL;
c472b432	193	copy_from_if_dqblk(&fdq, &idq);
74a8a103	194	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
c411e5f6 CH	195	}
	196
	197	static int quota_setxstate(struct super_block sb, int cmd, void __user addr)
	198	{
	199	__u32 flags;
	200
	201	if (copy_from_user(&flags, addr, sizeof(flags)))
	202	return -EFAULT;
f450d4fe CH	203	if (!sb->s_qcop->set_xstate)
f450d4fe CH	204	return -ENOSYS;
c411e5f6 CH	205	return sb->s_qcop->set_xstate(sb, flags, cmd);
	206	}
	207
	208	static int quota_getxstate(struct super_block sb, void __user addr)
	209	{
	210	struct fs_quota_stat fqs;
	211	int ret;
f450d4fe CH	212
	213	if (!sb->s_qcop->get_xstate)
	214	return -ENOSYS;
c411e5f6 CH	215	ret = sb->s_qcop->get_xstate(sb, &fqs);
	216	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
	217	return -EFAULT;
	218	return ret;
	219	}
1da177e4	220
af30cb44 CS	221	static int quota_getxstatev(struct super_block sb, void __user addr)
	222	{
	223	struct fs_quota_statv fqs;
	224	int ret;
	225
	226	if (!sb->s_qcop->get_xstatev)
	227	return -ENOSYS;
	228
	229	memset(&fqs, 0, sizeof(fqs));
	230	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
	231	return -EFAULT;
	232
	233	/* If this kernel doesn't support user specified version, fail */
	234	switch (fqs.qs_version) {
	235	case FS_QSTATV_VERSION1:
	236	break;
	237	default:
	238	return -EINVAL;
	239	}
	240	ret = sb->s_qcop->get_xstatev(sb, &fqs);
	241	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
	242	return -EFAULT;
	243	return ret;
	244	}
	245
c411e5f6 CH	246	static int quota_setxquota(struct super_block *sb, int type, qid_t id,
	247	void __user *addr)
	248	{
	249	struct fs_disk_quota fdq;
74a8a103	250	struct kqid qid;
c411e5f6 CH	251
	252	if (copy_from_user(&fdq, addr, sizeof(fdq)))
	253	return -EFAULT;
c472b432	254	if (!sb->s_qcop->set_dqblk)
f450d4fe	255	return -ENOSYS;
74a8a103 EB	256	qid = make_kqid(current_user_ns(), type, id);
	257	if (!qid_valid(qid))
	258	return -EINVAL;
	259	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
c411e5f6 CH	260	}
	261
	262	static int quota_getxquota(struct super_block *sb, int type, qid_t id,
	263	void __user *addr)
	264	{
	265	struct fs_disk_quota fdq;
74a8a103	266	struct kqid qid;
c411e5f6 CH	267	int ret;
c411e5f6 CH	268
b9b2dd36	269	if (!sb->s_qcop->get_dqblk)
f450d4fe	270	return -ENOSYS;
74a8a103 EB	271	qid = make_kqid(current_user_ns(), type, id);
	272	if (!qid_valid(qid))
	273	return -EINVAL;
	274	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
c411e5f6 CH	275	if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
	276	return -EFAULT;
	277	return ret;
	278	}
	279
	280	/* Copy parameters and call proper function */
	281	static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
f00c9e44	282	void __user addr, struct path path)
c411e5f6	283	{
c988afb5 CH	284	int ret;
	285
	286	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
	287	return -EINVAL;
	288	if (!sb->s_qcop)
	289	return -ENOSYS;
	290
	291	ret = check_quotactl_permission(sb, type, cmd, id);
	292	if (ret < 0)
	293	return ret;
	294
c411e5f6 CH	295	switch (cmd) {
c411e5f6 CH	296	case Q_QUOTAON:
f00c9e44	297	return quota_quotaon(sb, type, cmd, id, path);
c411e5f6	298	case Q_QUOTAOFF:
f450d4fe CH	299	if (!sb->s_qcop->quota_off)
f450d4fe CH	300	return -ENOSYS;
307ae18a	301	return sb->s_qcop->quota_off(sb, type);
c411e5f6 CH	302	case Q_GETFMT:
	303	return quota_getfmt(sb, type, addr);
	304	case Q_GETINFO:
	305	return quota_getinfo(sb, type, addr);
	306	case Q_SETINFO:
	307	return quota_setinfo(sb, type, addr);
	308	case Q_GETQUOTA:
	309	return quota_getquota(sb, type, id, addr);
	310	case Q_SETQUOTA:
	311	return quota_setquota(sb, type, id, addr);
	312	case Q_SYNC:
6ae09575 CH	313	if (!sb->s_qcop->quota_sync)
6ae09575 CH	314	return -ENOSYS;
ceed1723	315	return sb->s_qcop->quota_sync(sb, type);
c411e5f6 CH	316	case Q_XQUOTAON:
	317	case Q_XQUOTAOFF:
	318	case Q_XQUOTARM:
	319	return quota_setxstate(sb, cmd, addr);
	320	case Q_XGETQSTAT:
	321	return quota_getxstate(sb, addr);
af30cb44 CS	322	case Q_XGETQSTATV:
af30cb44 CS	323	return quota_getxstatev(sb, addr);
c411e5f6 CH	324	case Q_XSETQLIM:
	325	return quota_setxquota(sb, type, id, addr);
	326	case Q_XGETQUOTA:
	327	return quota_getxquota(sb, type, id, addr);
	328	case Q_XQUOTASYNC:
8c4e4acd CH	329	if (sb->s_flags & MS_RDONLY)
8c4e4acd CH	330	return -EROFS;
4b217ed9	331	/* XFS quotas are fully coherent now, making this call a noop */
8c4e4acd	332	return 0;
c411e5f6	333	default:
f450d4fe	334	return -EINVAL;
1da177e4	335	}
1da177e4 LT	336	}
1da177e4 LT	337
56df1278 LJ	338	#ifdef CONFIG_BLOCK
56df1278 LJ	339
dcdbed85 JK	340	/* Return 1 if 'cmd' will block on frozen filesystem */
	341	static int quotactl_cmd_write(int cmd)
	342	{
	343	switch (cmd) {
	344	case Q_GETFMT:
	345	case Q_GETINFO:
	346	case Q_SYNC:
	347	case Q_XGETQSTAT:
af30cb44	348	case Q_XGETQSTATV:
dcdbed85 JK	349	case Q_XGETQUOTA:
	350	case Q_XQUOTASYNC:
	351	return 0;
	352	}
	353	return 1;
	354	}
	355
56df1278 LJ	356	#endif /* CONFIG_BLOCK */
56df1278 LJ	357
9361401e DH	358	/*
	359	* look up a superblock on which quota ops will be performed
	360	* - use the name of a block device to find the superblock thereon
	361	*/
dcdbed85	362	static struct super_block quotactl_block(const char __user special, int cmd)
9361401e DH	363	{
	364	#ifdef CONFIG_BLOCK
	365	struct block_device *bdev;
	366	struct super_block *sb;
91a27b2a	367	struct filename *tmp = getname(special);
9361401e DH	368
9361401e DH	369	if (IS_ERR(tmp))
e231c2ee	370	return ERR_CAST(tmp);
91a27b2a	371	bdev = lookup_bdev(tmp->name);
9361401e DH	372	putname(tmp);
9361401e DH	373	if (IS_ERR(bdev))
e231c2ee	374	return ERR_CAST(bdev);
dcdbed85 JK	375	if (quotactl_cmd_write(cmd))
	376	sb = get_super_thawed(bdev);
	377	else
	378	sb = get_super(bdev);
9361401e DH	379	bdput(bdev);
	380	if (!sb)
	381	return ERR_PTR(-ENODEV);
	382
	383	return sb;
	384	#else
	385	return ERR_PTR(-ENODEV);
	386	#endif
	387	}
	388
1da177e4 LT	389	/*
	390	* This is the system call interface. This communicates with
	391	* the user-level programs. Currently this only supports diskquota
	392	* calls. Maybe we need to add the process quotas etc. in the future,
	393	* but we probably should use rlimits for that.
	394	*/
3cdad428 HC	395	SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
3cdad428 HC	396	qid_t, id, void __user *, addr)
1da177e4 LT	397	{
	398	uint cmds, type;
	399	struct super_block *sb = NULL;
f00c9e44	400	struct path path, *pathp = NULL;
1da177e4 LT	401	int ret;
	402
	403	cmds = cmd >> SUBCMDSHIFT;
	404	type = cmd & SUBCMDMASK;
	405
6ae09575 CH	406	/*
	407	* As a special case Q_SYNC can be called without a specific device.
	408	* It will iterate all superblocks that have quota enabled and call
	409	* the sync action on each of them.
	410	*/
	411	if (!special) {
	412	if (cmds == Q_SYNC)
	413	return quota_sync_all(type);
	414	return -ENODEV;
1da177e4 LT	415	}
1da177e4 LT	416
f00c9e44 JK	417	/*
	418	* Path for quotaon has to be resolved before grabbing superblock
	419	* because that gets s_umount sem which is also possibly needed by path
	420	* resolution (think about autofs) and thus deadlocks could arise.
	421	*/
	422	if (cmds == Q_QUOTAON) {
815d405c	423	ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW\|LOOKUP_AUTOMOUNT, &path);
f00c9e44 JK	424	if (ret)
	425	pathp = ERR_PTR(ret);
	426	else
	427	pathp = &path;
	428	}
	429
dcdbed85	430	sb = quotactl_block(special, cmds);
0aaa6188 JK	431	if (IS_ERR(sb)) {
	432	ret = PTR_ERR(sb);
	433	goto out;
	434	}
6ae09575	435
f00c9e44	436	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
1da177e4	437
6ae09575	438	drop_super(sb);
0aaa6188	439	out:
f00c9e44 JK	440	if (pathp && !IS_ERR(pathp))
f00c9e44 JK	441	path_put(pathp);
1da177e4 LT	442	return ret;
1da177e4 LT	443	}