[linux.git] / fs / quota / netlink.c

#include <linux/cred.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/quotaops.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <net/netlink.h>
#include <net/genetlink.h>

static const struct genl_multicast_group quota_mcgrps[] = {
	{ .name = "events", },
};

/* Netlink family structure for quota */
static struct genl_family quota_genl_family __ro_after_init = {
	.module = THIS_MODULE,
	.hdrsize = 0,
	.name = "VFS_DQUOT",
	.version = 1,
	.maxattr = QUOTA_NL_A_MAX,
	.mcgrps = quota_mcgrps,
	.n_mcgrps = ARRAY_SIZE(quota_mcgrps),
};

/**
 * quota_send_warning - Send warning to userspace about exceeded quota
 * @qid: The kernel internal quota identifier.
 * @dev: The device on which the fs is mounted (sb->s_dev)
 * @warntype: The type of the warning: QUOTA_NL_...
 *
 * This can be used by filesystems (including those which don't use
 * dquot) to send a message to userspace relating to quota limits.
 *
 */

void quota_send_warning(struct kqid qid, dev_t dev,
			const char warntype)
{
	static atomic_t seq;
	struct sk_buff *skb;
	void *msg_head;
	int ret;
	int msg_size = 4 * nla_total_size(sizeof(u32)) +
		       2 * nla_total_size_64bit(sizeof(u64));

	/* We have to allocate using GFP_NOFS as we are called from a
	 * filesystem performing write and thus further recursion into
	 * the fs to free some data could cause deadlocks. */
	skb = genlmsg_new(msg_size, GFP_NOFS);
	if (!skb) {
		printk(KERN_ERR
		  "VFS: Not enough memory to send quota warning.\n");
		return;
	}
	msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
			&quota_genl_family, 0, QUOTA_NL_C_WARNING);
	if (!msg_head) {
		printk(KERN_ERR
		  "VFS: Cannot store netlink header in quota warning.\n");
		goto err_out;
	}
	ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
	if (ret)
		goto attr_err_out;
	ret = nla_put_u64_64bit(skb, QUOTA_NL_A_EXCESS_ID,
				from_kqid_munged(&init_user_ns, qid),
				QUOTA_NL_A_PAD);
	if (ret)
		goto attr_err_out;
	ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
	if (ret)
		goto attr_err_out;
	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
	if (ret)
		goto attr_err_out;
	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
	if (ret)
		goto attr_err_out;
	ret = nla_put_u64_64bit(skb, QUOTA_NL_A_CAUSED_ID,
				from_kuid_munged(&init_user_ns, current_uid()),
				QUOTA_NL_A_PAD);
	if (ret)
		goto attr_err_out;
	genlmsg_end(skb, msg_head);

	genlmsg_multicast(&quota_genl_family, skb, 0, 0, GFP_NOFS);
	return;
attr_err_out:
	printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
err_out:
	kfree_skb(skb);
}
EXPORT_SYMBOL(quota_send_warning);

static int __init quota_init(void)
{
	if (genl_register_family(&quota_genl_family) != 0)
		printk(KERN_ERR
		       "VFS: Failed to create quota netlink interface.\n");
	return 0;
};
fs_initcall(quota_init);
Commit	Line	Data
799a9d44 CH	1	#include <linux/cred.h>
799a9d44 CH	2	#include <linux/init.h>
799a9d44 CH	3	#include <linux/kernel.h>
	4	#include <linux/quotaops.h>
	5	#include <linux/sched.h>
5a0e3ad6	6	#include <linux/slab.h>
799a9d44 CH	7	#include <net/netlink.h>
	8	#include <net/genetlink.h>
	9
2a94fe48 JB	10	static const struct genl_multicast_group quota_mcgrps[] = {
	11	{ .name = "events", },
	12	};
	13
799a9d44	14	/* Netlink family structure for quota */
56989f6d	15	static struct genl_family quota_genl_family __ro_after_init = {
489111e5	16	.module = THIS_MODULE,
799a9d44 CH	17	.hdrsize = 0,
	18	.name = "VFS_DQUOT",
	19	.version = 1,
	20	.maxattr = QUOTA_NL_A_MAX,
2a94fe48 JB	21	.mcgrps = quota_mcgrps,
2a94fe48 JB	22	.n_mcgrps = ARRAY_SIZE(quota_mcgrps),
2ecf7536 JB	23	};
2ecf7536 JB	24
799a9d44 CH	25	/**
799a9d44 CH	26	* quota_send_warning - Send warning to userspace about exceeded quota
2c15ac5b	27	* @qid: The kernel internal quota identifier.
799a9d44 CH	28	* @dev: The device on which the fs is mounted (sb->s_dev)
	29	* @warntype: The type of the warning: QUOTA_NL_...
	30	*
	31	* This can be used by filesystems (including those which don't use
	32	* dquot) to send a message to userspace relating to quota limits.
	33	*
	34	*/
	35
431f1974	36	void quota_send_warning(struct kqid qid, dev_t dev,
799a9d44 CH	37	const char warntype)
	38	{
	39	static atomic_t seq;
	40	struct sk_buff *skb;
	41	void *msg_head;
	42	int ret;
	43	int msg_size = 4 * nla_total_size(sizeof(u32)) +
3c6f3714	44	2 * nla_total_size_64bit(sizeof(u64));
799a9d44 CH	45
	46	/* We have to allocate using GFP_NOFS as we are called from a
	47	* filesystem performing write and thus further recursion into
	48	* the fs to free some data could cause deadlocks. */
	49	skb = genlmsg_new(msg_size, GFP_NOFS);
	50	if (!skb) {
	51	printk(KERN_ERR
	52	"VFS: Not enough memory to send quota warning.\n");
	53	return;
	54	}
	55	msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
	56	&quota_genl_family, 0, QUOTA_NL_C_WARNING);
	57	if (!msg_head) {
	58	printk(KERN_ERR
	59	"VFS: Cannot store netlink header in quota warning.\n");
	60	goto err_out;
	61	}
431f1974	62	ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
799a9d44 CH	63	if (ret)
799a9d44 CH	64	goto attr_err_out;
3c6f3714 ND	65	ret = nla_put_u64_64bit(skb, QUOTA_NL_A_EXCESS_ID,
	66	from_kqid_munged(&init_user_ns, qid),
	67	QUOTA_NL_A_PAD);
799a9d44 CH	68	if (ret)
	69	goto attr_err_out;
	70	ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
	71	if (ret)
	72	goto attr_err_out;
	73	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
	74	if (ret)
	75	goto attr_err_out;
	76	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
	77	if (ret)
	78	goto attr_err_out;
3c6f3714 ND	79	ret = nla_put_u64_64bit(skb, QUOTA_NL_A_CAUSED_ID,
	80	from_kuid_munged(&init_user_ns, current_uid()),
	81	QUOTA_NL_A_PAD);
799a9d44 CH	82	if (ret)
	83	goto attr_err_out;
	84	genlmsg_end(skb, msg_head);
	85
2a94fe48	86	genlmsg_multicast(&quota_genl_family, skb, 0, 0, GFP_NOFS);
799a9d44 CH	87	return;
	88	attr_err_out:
	89	printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
	90	err_out:
	91	kfree_skb(skb);
	92	}
	93	EXPORT_SYMBOL(quota_send_warning);
	94
	95	static int __init quota_init(void)
	96	{
	97	if (genl_register_family(&quota_genl_family) != 0)
	98	printk(KERN_ERR
	99	"VFS: Failed to create quota netlink interface.\n");
	100	return 0;
	101	};
7da54463	102	fs_initcall(quota_init);