blob: bb2869f5dfd89528f6986528369438a8cc565efd [file] [log] [blame]
Christoph Hellwig799a9d42010-02-16 03:44:54 -05001
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09008#include <linux/slab.h>
Christoph Hellwig799a9d42010-02-16 03:44:54 -05009#include <net/netlink.h>
10#include <net/genetlink.h>
11
Johannes Berg2a94fe42013-11-19 15:19:39 +010012static const struct genl_multicast_group quota_mcgrps[] = {
13 { .name = "events", },
14};
15
Christoph Hellwig799a9d42010-02-16 03:44:54 -050016/* Netlink family structure for quota */
17static struct genl_family quota_genl_family = {
Johannes Berg2ecf7532013-11-19 15:19:33 +010018 /*
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.
23 */
24 .id = GENL_ID_VFS_DQUOT,
Christoph Hellwig799a9d42010-02-16 03:44:54 -050025 .hdrsize = 0,
26 .name = "VFS_DQUOT",
27 .version = 1,
28 .maxattr = QUOTA_NL_A_MAX,
Johannes Berg2a94fe42013-11-19 15:19:39 +010029 .mcgrps = quota_mcgrps,
30 .n_mcgrps = ARRAY_SIZE(quota_mcgrps),
Johannes Berg2ecf7532013-11-19 15:19:33 +010031};
32
Christoph Hellwig799a9d42010-02-16 03:44:54 -050033/**
34 * quota_send_warning - Send warning to userspace about exceeded quota
Fabian Frederick2c15ac52014-07-04 21:44:25 +020035 * @qid: The kernel internal quota identifier.
Christoph Hellwig799a9d42010-02-16 03:44:54 -050036 * @dev: The device on which the fs is mounted (sb->s_dev)
37 * @warntype: The type of the warning: QUOTA_NL_...
38 *
39 * This can be used by filesystems (including those which don't use
40 * dquot) to send a message to userspace relating to quota limits.
41 *
42 */
43
Eric W. Biederman431f1972012-09-16 02:32:43 -070044void quota_send_warning(struct kqid qid, dev_t dev,
Christoph Hellwig799a9d42010-02-16 03:44:54 -050045 const char warntype)
46{
47 static atomic_t seq;
48 struct sk_buff *skb;
49 void *msg_head;
50 int ret;
51 int msg_size = 4 * nla_total_size(sizeof(u32)) +
52 2 * nla_total_size(sizeof(u64));
53
54 /* We have to allocate using GFP_NOFS as we are called from a
55 * filesystem performing write and thus further recursion into
56 * the fs to free some data could cause deadlocks. */
57 skb = genlmsg_new(msg_size, GFP_NOFS);
58 if (!skb) {
59 printk(KERN_ERR
60 "VFS: Not enough memory to send quota warning.\n");
61 return;
62 }
63 msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
64 &quota_genl_family, 0, QUOTA_NL_C_WARNING);
65 if (!msg_head) {
66 printk(KERN_ERR
67 "VFS: Cannot store netlink header in quota warning.\n");
68 goto err_out;
69 }
Eric W. Biederman431f1972012-09-16 02:32:43 -070070 ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
Christoph Hellwig799a9d42010-02-16 03:44:54 -050071 if (ret)
72 goto attr_err_out;
Eric W. Biederman431f1972012-09-16 02:32:43 -070073 ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID,
74 from_kqid_munged(&init_user_ns, qid));
Christoph Hellwig799a9d42010-02-16 03:44:54 -050075 if (ret)
76 goto attr_err_out;
77 ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
78 if (ret)
79 goto attr_err_out;
80 ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
81 if (ret)
82 goto attr_err_out;
83 ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
84 if (ret)
85 goto attr_err_out;
Eric W. Biederman431f1972012-09-16 02:32:43 -070086 ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID,
87 from_kuid_munged(&init_user_ns, current_uid()));
Christoph Hellwig799a9d42010-02-16 03:44:54 -050088 if (ret)
89 goto attr_err_out;
90 genlmsg_end(skb, msg_head);
91
Johannes Berg2a94fe42013-11-19 15:19:39 +010092 genlmsg_multicast(&quota_genl_family, skb, 0, 0, GFP_NOFS);
Christoph Hellwig799a9d42010-02-16 03:44:54 -050093 return;
94attr_err_out:
95 printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
96err_out:
97 kfree_skb(skb);
98}
99EXPORT_SYMBOL(quota_send_warning);
100
101static int __init quota_init(void)
102{
103 if (genl_register_family(&quota_genl_family) != 0)
104 printk(KERN_ERR
105 "VFS: Failed to create quota netlink interface.\n");
Christoph Hellwig799a9d42010-02-16 03:44:54 -0500106 return 0;
107};
108
109module_init(quota_init);