[linux-2.6-block.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)
{
	memset(dst, 0, sizeof(*dst));
	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;
}

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;
	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:
		return quota_setxstate(sb, cmd, 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)
	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)
b9b2dd36 CH	119	{
18da65e7	120	memset(dst, 0, sizeof(*dst));
b9b2dd36 CH	121	dst->dqb_bhardlimit = src->d_blk_hardlimit;
	122	dst->dqb_bsoftlimit = src->d_blk_softlimit;
	123	dst->dqb_curspace = src->d_bcount;
	124	dst->dqb_ihardlimit = src->d_ino_hardlimit;
	125	dst->dqb_isoftlimit = src->d_ino_softlimit;
	126	dst->dqb_curinodes = src->d_icount;
	127	dst->dqb_btime = src->d_btimer;
	128	dst->dqb_itime = src->d_itimer;
	129	dst->dqb_valid = QIF_ALL;
	130	}
	131
c411e5f6 CH	132	static int quota_getquota(struct super_block *sb, int type, qid_t id,
	133	void __user *addr)
	134	{
74a8a103	135	struct kqid qid;
b9b2dd36	136	struct fs_disk_quota fdq;
c411e5f6 CH	137	struct if_dqblk idq;
	138	int ret;
	139
f450d4fe CH	140	if (!sb->s_qcop->get_dqblk)
f450d4fe CH	141	return -ENOSYS;
74a8a103 EB	142	qid = make_kqid(current_user_ns(), type, id);
	143	if (!qid_valid(qid))
	144	return -EINVAL;
	145	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
c411e5f6 CH	146	if (ret)
c411e5f6 CH	147	return ret;
b9b2dd36	148	copy_to_if_dqblk(&idq, &fdq);
c411e5f6 CH	149	if (copy_to_user(addr, &idq, sizeof(idq)))
	150	return -EFAULT;
	151	return 0;
	152	}
	153
c472b432 CH	154	static void copy_from_if_dqblk(struct fs_disk_quota dst, struct if_dqblk src)
	155	{
	156	dst->d_blk_hardlimit = src->dqb_bhardlimit;
	157	dst->d_blk_softlimit = src->dqb_bsoftlimit;
	158	dst->d_bcount = src->dqb_curspace;
	159	dst->d_ino_hardlimit = src->dqb_ihardlimit;
	160	dst->d_ino_softlimit = src->dqb_isoftlimit;
	161	dst->d_icount = src->dqb_curinodes;
	162	dst->d_btimer = src->dqb_btime;
	163	dst->d_itimer = src->dqb_itime;
	164
	165	dst->d_fieldmask = 0;
	166	if (src->dqb_valid & QIF_BLIMITS)
	167	dst->d_fieldmask \|= FS_DQ_BSOFT \| FS_DQ_BHARD;
	168	if (src->dqb_valid & QIF_SPACE)
	169	dst->d_fieldmask \|= FS_DQ_BCOUNT;
	170	if (src->dqb_valid & QIF_ILIMITS)
	171	dst->d_fieldmask \|= FS_DQ_ISOFT \| FS_DQ_IHARD;
	172	if (src->dqb_valid & QIF_INODES)
	173	dst->d_fieldmask \|= FS_DQ_ICOUNT;
	174	if (src->dqb_valid & QIF_BTIME)
	175	dst->d_fieldmask \|= FS_DQ_BTIMER;
	176	if (src->dqb_valid & QIF_ITIME)
	177	dst->d_fieldmask \|= FS_DQ_ITIMER;
	178	}
	179
c411e5f6 CH	180	static int quota_setquota(struct super_block *sb, int type, qid_t id,
	181	void __user *addr)
	182	{
c472b432	183	struct fs_disk_quota fdq;
c411e5f6	184	struct if_dqblk idq;
74a8a103	185	struct kqid qid;
c411e5f6 CH	186
	187	if (copy_from_user(&idq, addr, sizeof(idq)))
	188	return -EFAULT;
f450d4fe CH	189	if (!sb->s_qcop->set_dqblk)
f450d4fe CH	190	return -ENOSYS;
74a8a103 EB	191	qid = make_kqid(current_user_ns(), type, id);
	192	if (!qid_valid(qid))
	193	return -EINVAL;
c472b432	194	copy_from_if_dqblk(&fdq, &idq);
74a8a103	195	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
c411e5f6 CH	196	}
	197
	198	static int quota_setxstate(struct super_block sb, int cmd, void __user addr)
	199	{
	200	__u32 flags;
	201
	202	if (copy_from_user(&flags, addr, sizeof(flags)))
	203	return -EFAULT;
f450d4fe CH	204	if (!sb->s_qcop->set_xstate)
f450d4fe CH	205	return -ENOSYS;
c411e5f6 CH	206	return sb->s_qcop->set_xstate(sb, flags, cmd);
	207	}
	208
	209	static int quota_getxstate(struct super_block sb, void __user addr)
	210	{
	211	struct fs_quota_stat fqs;
	212	int ret;
f450d4fe CH	213
	214	if (!sb->s_qcop->get_xstate)
	215	return -ENOSYS;
c411e5f6 CH	216	ret = sb->s_qcop->get_xstate(sb, &fqs);
	217	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
	218	return -EFAULT;
	219	return ret;
	220	}
1da177e4	221
af30cb44 CS	222	static int quota_getxstatev(struct super_block sb, void __user addr)
	223	{
	224	struct fs_quota_statv fqs;
	225	int ret;
	226
	227	if (!sb->s_qcop->get_xstatev)
	228	return -ENOSYS;
	229
	230	memset(&fqs, 0, sizeof(fqs));
	231	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
	232	return -EFAULT;
	233
	234	/* If this kernel doesn't support user specified version, fail */
	235	switch (fqs.qs_version) {
	236	case FS_QSTATV_VERSION1:
	237	break;
	238	default:
	239	return -EINVAL;
	240	}
	241	ret = sb->s_qcop->get_xstatev(sb, &fqs);
	242	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
	243	return -EFAULT;
	244	return ret;
	245	}
	246
c411e5f6 CH	247	static int quota_setxquota(struct super_block *sb, int type, qid_t id,
	248	void __user *addr)
	249	{
	250	struct fs_disk_quota fdq;
74a8a103	251	struct kqid qid;
c411e5f6 CH	252
	253	if (copy_from_user(&fdq, addr, sizeof(fdq)))
	254	return -EFAULT;
c472b432	255	if (!sb->s_qcop->set_dqblk)
f450d4fe	256	return -ENOSYS;
74a8a103 EB	257	qid = make_kqid(current_user_ns(), type, id);
	258	if (!qid_valid(qid))
	259	return -EINVAL;
	260	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
c411e5f6 CH	261	}
	262
	263	static int quota_getxquota(struct super_block *sb, int type, qid_t id,
	264	void __user *addr)
	265	{
	266	struct fs_disk_quota fdq;
74a8a103	267	struct kqid qid;
c411e5f6 CH	268	int ret;
c411e5f6 CH	269
b9b2dd36	270	if (!sb->s_qcop->get_dqblk)
f450d4fe	271	return -ENOSYS;
74a8a103 EB	272	qid = make_kqid(current_user_ns(), type, id);
	273	if (!qid_valid(qid))
	274	return -EINVAL;
	275	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
c411e5f6 CH	276	if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
	277	return -EFAULT;
	278	return ret;
	279	}
	280
9da93f9b ES	281	static int quota_rmxquota(struct super_block sb, void __user addr)
	282	{
	283	__u32 flags;
	284
	285	if (copy_from_user(&flags, addr, sizeof(flags)))
	286	return -EFAULT;
	287	if (!sb->s_qcop->rm_xquota)
	288	return -ENOSYS;
	289	return sb->s_qcop->rm_xquota(sb, flags);
	290	}
	291
c411e5f6 CH	292	/* Copy parameters and call proper function */
c411e5f6 CH	293	static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
f00c9e44	294	void __user addr, struct path path)
c411e5f6	295	{
c988afb5 CH	296	int ret;
	297
	298	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
	299	return -EINVAL;
	300	if (!sb->s_qcop)
	301	return -ENOSYS;
	302
	303	ret = check_quotactl_permission(sb, type, cmd, id);
	304	if (ret < 0)
	305	return ret;
	306
c411e5f6 CH	307	switch (cmd) {
c411e5f6 CH	308	case Q_QUOTAON:
f00c9e44	309	return quota_quotaon(sb, type, cmd, id, path);
c411e5f6	310	case Q_QUOTAOFF:
f450d4fe CH	311	if (!sb->s_qcop->quota_off)
f450d4fe CH	312	return -ENOSYS;
307ae18a	313	return sb->s_qcop->quota_off(sb, type);
c411e5f6 CH	314	case Q_GETFMT:
	315	return quota_getfmt(sb, type, addr);
	316	case Q_GETINFO:
	317	return quota_getinfo(sb, type, addr);
	318	case Q_SETINFO:
	319	return quota_setinfo(sb, type, addr);
	320	case Q_GETQUOTA:
	321	return quota_getquota(sb, type, id, addr);
	322	case Q_SETQUOTA:
	323	return quota_setquota(sb, type, id, addr);
	324	case Q_SYNC:
6ae09575 CH	325	if (!sb->s_qcop->quota_sync)
6ae09575 CH	326	return -ENOSYS;
ceed1723	327	return sb->s_qcop->quota_sync(sb, type);
c411e5f6 CH	328	case Q_XQUOTAON:
c411e5f6 CH	329	case Q_XQUOTAOFF:
c411e5f6	330	return quota_setxstate(sb, cmd, addr);
9da93f9b ES	331	case Q_XQUOTARM:
9da93f9b ES	332	return quota_rmxquota(sb, addr);
c411e5f6 CH	333	case Q_XGETQSTAT:
c411e5f6 CH	334	return quota_getxstate(sb, addr);
af30cb44 CS	335	case Q_XGETQSTATV:
af30cb44 CS	336	return quota_getxstatev(sb, addr);
c411e5f6 CH	337	case Q_XSETQLIM:
	338	return quota_setxquota(sb, type, id, addr);
	339	case Q_XGETQUOTA:
	340	return quota_getxquota(sb, type, id, addr);
	341	case Q_XQUOTASYNC:
8c4e4acd CH	342	if (sb->s_flags & MS_RDONLY)
8c4e4acd CH	343	return -EROFS;
4b217ed9	344	/* XFS quotas are fully coherent now, making this call a noop */
8c4e4acd	345	return 0;
c411e5f6	346	default:
f450d4fe	347	return -EINVAL;
1da177e4	348	}
1da177e4 LT	349	}
1da177e4 LT	350
56df1278 LJ	351	#ifdef CONFIG_BLOCK
56df1278 LJ	352
dcdbed85 JK	353	/* Return 1 if 'cmd' will block on frozen filesystem */
	354	static int quotactl_cmd_write(int cmd)
	355	{
	356	switch (cmd) {
	357	case Q_GETFMT:
	358	case Q_GETINFO:
	359	case Q_SYNC:
	360	case Q_XGETQSTAT:
af30cb44	361	case Q_XGETQSTATV:
dcdbed85 JK	362	case Q_XGETQUOTA:
	363	case Q_XQUOTASYNC:
	364	return 0;
	365	}
	366	return 1;
	367	}
	368
56df1278 LJ	369	#endif /* CONFIG_BLOCK */
56df1278 LJ	370
9361401e DH	371	/*
	372	* look up a superblock on which quota ops will be performed
	373	* - use the name of a block device to find the superblock thereon
	374	*/
dcdbed85	375	static struct super_block quotactl_block(const char __user special, int cmd)
9361401e DH	376	{
	377	#ifdef CONFIG_BLOCK
	378	struct block_device *bdev;
	379	struct super_block *sb;
91a27b2a	380	struct filename *tmp = getname(special);
9361401e DH	381
9361401e DH	382	if (IS_ERR(tmp))
e231c2ee	383	return ERR_CAST(tmp);
91a27b2a	384	bdev = lookup_bdev(tmp->name);
9361401e DH	385	putname(tmp);
9361401e DH	386	if (IS_ERR(bdev))
e231c2ee	387	return ERR_CAST(bdev);
dcdbed85 JK	388	if (quotactl_cmd_write(cmd))
	389	sb = get_super_thawed(bdev);
	390	else
	391	sb = get_super(bdev);
9361401e DH	392	bdput(bdev);
	393	if (!sb)
	394	return ERR_PTR(-ENODEV);
	395
	396	return sb;
	397	#else
	398	return ERR_PTR(-ENODEV);
	399	#endif
	400	}
	401
1da177e4 LT	402	/*
	403	* This is the system call interface. This communicates with
	404	* the user-level programs. Currently this only supports diskquota
	405	* calls. Maybe we need to add the process quotas etc. in the future,
	406	* but we probably should use rlimits for that.
	407	*/
3cdad428 HC	408	SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
3cdad428 HC	409	qid_t, id, void __user *, addr)
1da177e4 LT	410	{
	411	uint cmds, type;
	412	struct super_block *sb = NULL;
f00c9e44	413	struct path path, *pathp = NULL;
1da177e4 LT	414	int ret;
	415
	416	cmds = cmd >> SUBCMDSHIFT;
	417	type = cmd & SUBCMDMASK;
	418
6ae09575 CH	419	/*
	420	* As a special case Q_SYNC can be called without a specific device.
	421	* It will iterate all superblocks that have quota enabled and call
	422	* the sync action on each of them.
	423	*/
	424	if (!special) {
	425	if (cmds == Q_SYNC)
	426	return quota_sync_all(type);
	427	return -ENODEV;
1da177e4 LT	428	}
1da177e4 LT	429
f00c9e44 JK	430	/*
	431	* Path for quotaon has to be resolved before grabbing superblock
	432	* because that gets s_umount sem which is also possibly needed by path
	433	* resolution (think about autofs) and thus deadlocks could arise.
	434	*/
	435	if (cmds == Q_QUOTAON) {
815d405c	436	ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW\|LOOKUP_AUTOMOUNT, &path);
f00c9e44 JK	437	if (ret)
	438	pathp = ERR_PTR(ret);
	439	else
	440	pathp = &path;
	441	}
	442
dcdbed85	443	sb = quotactl_block(special, cmds);
0aaa6188 JK	444	if (IS_ERR(sb)) {
	445	ret = PTR_ERR(sb);
	446	goto out;
	447	}
6ae09575	448
f00c9e44	449	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
1da177e4	450
6ae09575	451	drop_super(sb);
0aaa6188	452	out:
f00c9e44 JK	453	if (pathp && !IS_ERR(pathp))
f00c9e44 JK	454	path_put(pathp);
1da177e4 LT	455	return ret;
1da177e4 LT	456	}