2 #include <linux/cred.h>
3 #include <linux/init.h>
4 #include <linux/module.h>
5 #include <linux/kernel.h>
6 #include <linux/quotaops.h>
7 #include <linux/sched.h>
8 #include <linux/slab.h>
9 #include <net/netlink.h>
10 #include <net/genetlink.h>
12 static const struct genl_multicast_group quota_mcgrps[] = {
13 { .name = "events", },
16 /* Netlink family structure for quota */
17 static struct genl_family quota_genl_family = {
19 * Needed due to multicast group ID abuse - old code assumed
20 * the family ID was also a valid multicast group ID (which
21 * isn't true) and userspace might thus rely on it. Assign a
22 * static ID for this group to make dealing with that easier.
24 .id = GENL_ID_VFS_DQUOT,
28 .maxattr = QUOTA_NL_A_MAX,
29 .mcgrps = quota_mcgrps,
30 .n_mcgrps = ARRAY_SIZE(quota_mcgrps),
34 * quota_send_warning - Send warning to userspace about exceeded quota
35 * @type: The quota type: USRQQUOTA, GRPQUOTA,...
36 * @id: The user or group id of the quota that was exceeded
37 * @dev: The device on which the fs is mounted (sb->s_dev)
38 * @warntype: The type of the warning: QUOTA_NL_...
40 * This can be used by filesystems (including those which don't use
41 * dquot) to send a message to userspace relating to quota limits.
45 void quota_send_warning(struct kqid qid, dev_t dev,
52 int msg_size = 4 * nla_total_size(sizeof(u32)) +
53 2 * nla_total_size(sizeof(u64));
55 /* We have to allocate using GFP_NOFS as we are called from a
56 * filesystem performing write and thus further recursion into
57 * the fs to free some data could cause deadlocks. */
58 skb = genlmsg_new(msg_size, GFP_NOFS);
61 "VFS: Not enough memory to send quota warning.\n");
64 msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
65 "a_genl_family, 0, QUOTA_NL_C_WARNING);
68 "VFS: Cannot store netlink header in quota warning.\n");
71 ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
74 ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID,
75 from_kqid_munged(&init_user_ns, qid));
78 ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
81 ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
84 ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
87 ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID,
88 from_kuid_munged(&init_user_ns, current_uid()));
91 genlmsg_end(skb, msg_head);
93 genlmsg_multicast("a_genl_family, skb, 0, 0, GFP_NOFS);
96 printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
100 EXPORT_SYMBOL(quota_send_warning);
102 static int __init quota_init(void)
104 if (genl_register_family("a_genl_family) != 0)
106 "VFS: Failed to create quota netlink interface.\n");
110 module_init(quota_init);