1*b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0
2799a9d44SChristoph Hellwig #include <linux/cred.h>
3799a9d44SChristoph Hellwig #include <linux/init.h>
4799a9d44SChristoph Hellwig #include <linux/kernel.h>
5799a9d44SChristoph Hellwig #include <linux/quotaops.h>
6799a9d44SChristoph Hellwig #include <linux/sched.h>
75a0e3ad6STejun Heo #include <linux/slab.h>
8799a9d44SChristoph Hellwig #include <net/netlink.h>
9799a9d44SChristoph Hellwig #include <net/genetlink.h>
10799a9d44SChristoph Hellwig
112a94fe48SJohannes Berg static const struct genl_multicast_group quota_mcgrps[] = {
122a94fe48SJohannes Berg { .name = "events", },
132a94fe48SJohannes Berg };
142a94fe48SJohannes Berg
15799a9d44SChristoph Hellwig /* Netlink family structure for quota */
1656989f6dSJohannes Berg static struct genl_family quota_genl_family __ro_after_init = {
17489111e5SJohannes Berg .module = THIS_MODULE,
18799a9d44SChristoph Hellwig .hdrsize = 0,
19799a9d44SChristoph Hellwig .name = "VFS_DQUOT",
20799a9d44SChristoph Hellwig .version = 1,
21799a9d44SChristoph Hellwig .maxattr = QUOTA_NL_A_MAX,
222a94fe48SJohannes Berg .mcgrps = quota_mcgrps,
232a94fe48SJohannes Berg .n_mcgrps = ARRAY_SIZE(quota_mcgrps),
242ecf7536SJohannes Berg };
252ecf7536SJohannes Berg
26799a9d44SChristoph Hellwig /**
27799a9d44SChristoph Hellwig * quota_send_warning - Send warning to userspace about exceeded quota
282c15ac5bSFabian Frederick * @qid: The kernel internal quota identifier.
29799a9d44SChristoph Hellwig * @dev: The device on which the fs is mounted (sb->s_dev)
30799a9d44SChristoph Hellwig * @warntype: The type of the warning: QUOTA_NL_...
31799a9d44SChristoph Hellwig *
32799a9d44SChristoph Hellwig * This can be used by filesystems (including those which don't use
33799a9d44SChristoph Hellwig * dquot) to send a message to userspace relating to quota limits.
34799a9d44SChristoph Hellwig *
35799a9d44SChristoph Hellwig */
36799a9d44SChristoph Hellwig
quota_send_warning(struct kqid qid,dev_t dev,const char warntype)37431f1974SEric W. Biederman void quota_send_warning(struct kqid qid, dev_t dev,
38799a9d44SChristoph Hellwig const char warntype)
39799a9d44SChristoph Hellwig {
40799a9d44SChristoph Hellwig static atomic_t seq;
41799a9d44SChristoph Hellwig struct sk_buff *skb;
42799a9d44SChristoph Hellwig void *msg_head;
43799a9d44SChristoph Hellwig int ret;
44799a9d44SChristoph Hellwig int msg_size = 4 * nla_total_size(sizeof(u32)) +
453c6f3714SNicolas Dichtel 2 * nla_total_size_64bit(sizeof(u64));
46799a9d44SChristoph Hellwig
47799a9d44SChristoph Hellwig /* We have to allocate using GFP_NOFS as we are called from a
48799a9d44SChristoph Hellwig * filesystem performing write and thus further recursion into
49799a9d44SChristoph Hellwig * the fs to free some data could cause deadlocks. */
50799a9d44SChristoph Hellwig skb = genlmsg_new(msg_size, GFP_NOFS);
51799a9d44SChristoph Hellwig if (!skb) {
52799a9d44SChristoph Hellwig printk(KERN_ERR
53799a9d44SChristoph Hellwig "VFS: Not enough memory to send quota warning.\n");
54799a9d44SChristoph Hellwig return;
55799a9d44SChristoph Hellwig }
56799a9d44SChristoph Hellwig msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
57799a9d44SChristoph Hellwig "a_genl_family, 0, QUOTA_NL_C_WARNING);
58799a9d44SChristoph Hellwig if (!msg_head) {
59799a9d44SChristoph Hellwig printk(KERN_ERR
60799a9d44SChristoph Hellwig "VFS: Cannot store netlink header in quota warning.\n");
61799a9d44SChristoph Hellwig goto err_out;
62799a9d44SChristoph Hellwig }
63431f1974SEric W. Biederman ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
64799a9d44SChristoph Hellwig if (ret)
65799a9d44SChristoph Hellwig goto attr_err_out;
663c6f3714SNicolas Dichtel ret = nla_put_u64_64bit(skb, QUOTA_NL_A_EXCESS_ID,
673c6f3714SNicolas Dichtel from_kqid_munged(&init_user_ns, qid),
683c6f3714SNicolas Dichtel QUOTA_NL_A_PAD);
69799a9d44SChristoph Hellwig if (ret)
70799a9d44SChristoph Hellwig goto attr_err_out;
71799a9d44SChristoph Hellwig ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
72799a9d44SChristoph Hellwig if (ret)
73799a9d44SChristoph Hellwig goto attr_err_out;
74799a9d44SChristoph Hellwig ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
75799a9d44SChristoph Hellwig if (ret)
76799a9d44SChristoph Hellwig goto attr_err_out;
77799a9d44SChristoph Hellwig ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
78799a9d44SChristoph Hellwig if (ret)
79799a9d44SChristoph Hellwig goto attr_err_out;
803c6f3714SNicolas Dichtel ret = nla_put_u64_64bit(skb, QUOTA_NL_A_CAUSED_ID,
813c6f3714SNicolas Dichtel from_kuid_munged(&init_user_ns, current_uid()),
823c6f3714SNicolas Dichtel QUOTA_NL_A_PAD);
83799a9d44SChristoph Hellwig if (ret)
84799a9d44SChristoph Hellwig goto attr_err_out;
85799a9d44SChristoph Hellwig genlmsg_end(skb, msg_head);
86799a9d44SChristoph Hellwig
872a94fe48SJohannes Berg genlmsg_multicast("a_genl_family, skb, 0, 0, GFP_NOFS);
88799a9d44SChristoph Hellwig return;
89799a9d44SChristoph Hellwig attr_err_out:
90799a9d44SChristoph Hellwig printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
91799a9d44SChristoph Hellwig err_out:
92799a9d44SChristoph Hellwig kfree_skb(skb);
93799a9d44SChristoph Hellwig }
94799a9d44SChristoph Hellwig EXPORT_SYMBOL(quota_send_warning);
95799a9d44SChristoph Hellwig
quota_init(void)96799a9d44SChristoph Hellwig static int __init quota_init(void)
97799a9d44SChristoph Hellwig {
98799a9d44SChristoph Hellwig if (genl_register_family("a_genl_family) != 0)
99799a9d44SChristoph Hellwig printk(KERN_ERR
100799a9d44SChristoph Hellwig "VFS: Failed to create quota netlink interface.\n");
101799a9d44SChristoph Hellwig return 0;
102799a9d44SChristoph Hellwig };
1037da54463SPaul Gortmaker fs_initcall(quota_init);
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