Commit | Line | Data |
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799a9d44 CH |
1 | |
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 <net/netlink.h> | |
9 | #include <net/genetlink.h> | |
10 | ||
11 | /* Netlink family structure for quota */ | |
12 | static struct genl_family quota_genl_family = { | |
13 | .id = GENL_ID_GENERATE, | |
14 | .hdrsize = 0, | |
15 | .name = "VFS_DQUOT", | |
16 | .version = 1, | |
17 | .maxattr = QUOTA_NL_A_MAX, | |
18 | }; | |
19 | ||
20 | /** | |
21 | * quota_send_warning - Send warning to userspace about exceeded quota | |
22 | * @type: The quota type: USRQQUOTA, GRPQUOTA,... | |
23 | * @id: The user or group id of the quota that was exceeded | |
24 | * @dev: The device on which the fs is mounted (sb->s_dev) | |
25 | * @warntype: The type of the warning: QUOTA_NL_... | |
26 | * | |
27 | * This can be used by filesystems (including those which don't use | |
28 | * dquot) to send a message to userspace relating to quota limits. | |
29 | * | |
30 | */ | |
31 | ||
32 | void quota_send_warning(short type, unsigned int id, dev_t dev, | |
33 | const char warntype) | |
34 | { | |
35 | static atomic_t seq; | |
36 | struct sk_buff *skb; | |
37 | void *msg_head; | |
38 | int ret; | |
39 | int msg_size = 4 * nla_total_size(sizeof(u32)) + | |
40 | 2 * nla_total_size(sizeof(u64)); | |
41 | ||
42 | /* We have to allocate using GFP_NOFS as we are called from a | |
43 | * filesystem performing write and thus further recursion into | |
44 | * the fs to free some data could cause deadlocks. */ | |
45 | skb = genlmsg_new(msg_size, GFP_NOFS); | |
46 | if (!skb) { | |
47 | printk(KERN_ERR | |
48 | "VFS: Not enough memory to send quota warning.\n"); | |
49 | return; | |
50 | } | |
51 | msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq), | |
52 | "a_genl_family, 0, QUOTA_NL_C_WARNING); | |
53 | if (!msg_head) { | |
54 | printk(KERN_ERR | |
55 | "VFS: Cannot store netlink header in quota warning.\n"); | |
56 | goto err_out; | |
57 | } | |
58 | ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, type); | |
59 | if (ret) | |
60 | goto attr_err_out; | |
61 | ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, id); | |
62 | if (ret) | |
63 | goto attr_err_out; | |
64 | ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype); | |
65 | if (ret) | |
66 | goto attr_err_out; | |
67 | ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev)); | |
68 | if (ret) | |
69 | goto attr_err_out; | |
70 | ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev)); | |
71 | if (ret) | |
72 | goto attr_err_out; | |
73 | ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current_uid()); | |
74 | if (ret) | |
75 | goto attr_err_out; | |
76 | genlmsg_end(skb, msg_head); | |
77 | ||
78 | genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS); | |
79 | return; | |
80 | attr_err_out: | |
81 | printk(KERN_ERR "VFS: Not enough space to compose quota message!\n"); | |
82 | err_out: | |
83 | kfree_skb(skb); | |
84 | } | |
85 | EXPORT_SYMBOL(quota_send_warning); | |
86 | ||
87 | static int __init quota_init(void) | |
88 | { | |
89 | if (genl_register_family("a_genl_family) != 0) | |
90 | printk(KERN_ERR | |
91 | "VFS: Failed to create quota netlink interface.\n"); | |
92 | return 0; | |
93 | }; | |
94 | ||
95 | module_init(quota_init); |