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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
799a9d44 CH |
2 | #include <linux/cred.h> |
3 | #include <linux/init.h> | |
799a9d44 CH |
4 | #include <linux/kernel.h> |
5 | #include <linux/quotaops.h> | |
6 | #include <linux/sched.h> | |
5a0e3ad6 | 7 | #include <linux/slab.h> |
799a9d44 CH |
8 | #include <net/netlink.h> |
9 | #include <net/genetlink.h> | |
10 | ||
2a94fe48 JB |
11 | static const struct genl_multicast_group quota_mcgrps[] = { |
12 | { .name = "events", }, | |
13 | }; | |
14 | ||
799a9d44 | 15 | /* Netlink family structure for quota */ |
56989f6d | 16 | static struct genl_family quota_genl_family __ro_after_init = { |
489111e5 | 17 | .module = THIS_MODULE, |
799a9d44 CH |
18 | .hdrsize = 0, |
19 | .name = "VFS_DQUOT", | |
20 | .version = 1, | |
21 | .maxattr = QUOTA_NL_A_MAX, | |
2a94fe48 JB |
22 | .mcgrps = quota_mcgrps, |
23 | .n_mcgrps = ARRAY_SIZE(quota_mcgrps), | |
2ecf7536 JB |
24 | }; |
25 | ||
799a9d44 CH |
26 | /** |
27 | * quota_send_warning - Send warning to userspace about exceeded quota | |
2c15ac5b | 28 | * @qid: The kernel internal quota identifier. |
799a9d44 CH |
29 | * @dev: The device on which the fs is mounted (sb->s_dev) |
30 | * @warntype: The type of the warning: QUOTA_NL_... | |
31 | * | |
32 | * This can be used by filesystems (including those which don't use | |
33 | * dquot) to send a message to userspace relating to quota limits. | |
34 | * | |
35 | */ | |
36 | ||
431f1974 | 37 | void quota_send_warning(struct kqid qid, dev_t dev, |
799a9d44 CH |
38 | const char warntype) |
39 | { | |
40 | static atomic_t seq; | |
41 | struct sk_buff *skb; | |
42 | void *msg_head; | |
43 | int ret; | |
44 | int msg_size = 4 * nla_total_size(sizeof(u32)) + | |
3c6f3714 | 45 | 2 * nla_total_size_64bit(sizeof(u64)); |
799a9d44 CH |
46 | |
47 | /* We have to allocate using GFP_NOFS as we are called from a | |
48 | * filesystem performing write and thus further recursion into | |
49 | * the fs to free some data could cause deadlocks. */ | |
50 | skb = genlmsg_new(msg_size, GFP_NOFS); | |
51 | if (!skb) { | |
52 | printk(KERN_ERR | |
53 | "VFS: Not enough memory to send quota warning.\n"); | |
54 | return; | |
55 | } | |
56 | msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq), | |
57 | "a_genl_family, 0, QUOTA_NL_C_WARNING); | |
58 | if (!msg_head) { | |
59 | printk(KERN_ERR | |
60 | "VFS: Cannot store netlink header in quota warning.\n"); | |
61 | goto err_out; | |
62 | } | |
431f1974 | 63 | ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type); |
799a9d44 CH |
64 | if (ret) |
65 | goto attr_err_out; | |
3c6f3714 ND |
66 | ret = nla_put_u64_64bit(skb, QUOTA_NL_A_EXCESS_ID, |
67 | from_kqid_munged(&init_user_ns, qid), | |
68 | QUOTA_NL_A_PAD); | |
799a9d44 CH |
69 | if (ret) |
70 | goto attr_err_out; | |
71 | ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype); | |
72 | if (ret) | |
73 | goto attr_err_out; | |
74 | ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev)); | |
75 | if (ret) | |
76 | goto attr_err_out; | |
77 | ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev)); | |
78 | if (ret) | |
79 | goto attr_err_out; | |
3c6f3714 ND |
80 | ret = nla_put_u64_64bit(skb, QUOTA_NL_A_CAUSED_ID, |
81 | from_kuid_munged(&init_user_ns, current_uid()), | |
82 | QUOTA_NL_A_PAD); | |
799a9d44 CH |
83 | if (ret) |
84 | goto attr_err_out; | |
85 | genlmsg_end(skb, msg_head); | |
86 | ||
2a94fe48 | 87 | genlmsg_multicast("a_genl_family, skb, 0, 0, GFP_NOFS); |
799a9d44 CH |
88 | return; |
89 | attr_err_out: | |
90 | printk(KERN_ERR "VFS: Not enough space to compose quota message!\n"); | |
91 | err_out: | |
92 | kfree_skb(skb); | |
93 | } | |
94 | EXPORT_SYMBOL(quota_send_warning); | |
95 | ||
96 | static int __init quota_init(void) | |
97 | { | |
98 | if (genl_register_family("a_genl_family) != 0) | |
99 | printk(KERN_ERR | |
100 | "VFS: Failed to create quota netlink interface.\n"); | |
101 | return 0; | |
102 | }; | |
7da54463 | 103 | fs_initcall(quota_init); |