projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 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> | |
| 5a0e3ad6 | 8 | #include <linux/slab.h> |
| 799a9d44 CH |
9 | #include <net/netlink.h> |
| 10 | #include <net/genetlink.h> | |
| 11 | ||
| 12 | /* Netlink family structure for quota */ | |
| 13 | static struct genl_family quota_genl_family = { | |
| 14 | .id = GENL_ID_GENERATE, | |
| 15 | .hdrsize = 0, | |
| 16 | .name = "VFS_DQUOT", | |
| 17 | .version = 1, | |
| 18 | .maxattr = QUOTA_NL_A_MAX, | |
| 19 | }; | |
| 20 | ||
| 21 | /** | |
| 22 | * quota_send_warning - Send warning to userspace about exceeded quota | |
| 23 | * @type: The quota type: USRQQUOTA, GRPQUOTA,... | |
| 24 | * @id: The user or group id of the quota that was exceeded | |
| 25 | * @dev: The device on which the fs is mounted (sb->s_dev) | |
| 26 | * @warntype: The type of the warning: QUOTA_NL_... | |
| 27 | * | |
| 28 | * This can be used by filesystems (including those which don't use | |
| 29 | * dquot) to send a message to userspace relating to quota limits. | |
| 30 | * | |
| 31 | */ | |
| 32 | ||
| 33 | void quota_send_warning(short type, unsigned int id, dev_t dev, | |
| 34 | const char warntype) | |
| 35 | { | |
| 36 | static atomic_t seq; | |
| 37 | struct sk_buff *skb; | |
| 38 | void *msg_head; | |
| 39 | int ret; | |
| 40 | int msg_size = 4 * nla_total_size(sizeof(u32)) + | |
| 41 | 2 * nla_total_size(sizeof(u64)); | |
| 42 | ||
| 43 | /* We have to allocate using GFP_NOFS as we are called from a | |
| 44 | * filesystem performing write and thus further recursion into | |
| 45 | * the fs to free some data could cause deadlocks. */ | |
| 46 | skb = genlmsg_new(msg_size, GFP_NOFS); | |
| 47 | if (!skb) { | |
| 48 | printk(KERN_ERR | |
| 49 | "VFS: Not enough memory to send quota warning.\n"); | |
| 50 | return; | |
| 51 | } | |
| 52 | msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq), | |
| 53 | "a_genl_family, 0, QUOTA_NL_C_WARNING); | |
| 54 | if (!msg_head) { | |
| 55 | printk(KERN_ERR | |
| 56 | "VFS: Cannot store netlink header in quota warning.\n"); | |
| 57 | goto err_out; | |
| 58 | } | |
| 59 | ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, type); | |
| 60 | if (ret) | |
| 61 | goto attr_err_out; | |
| 62 | ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, id); | |
| 63 | if (ret) | |
| 64 | goto attr_err_out; | |
| 65 | ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype); | |
| 66 | if (ret) | |
| 67 | goto attr_err_out; | |
| 68 | ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev)); | |
| 69 | if (ret) | |
| 70 | goto attr_err_out; | |
| 71 | ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev)); | |
| 72 | if (ret) | |
| 73 | goto attr_err_out; | |
| 74 | ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current_uid()); | |
| 75 | if (ret) | |
| 76 | goto attr_err_out; | |
| 77 | genlmsg_end(skb, msg_head); | |
| 78 | ||
| 79 | genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS); | |
| 80 | return; | |
| 81 | attr_err_out: | |
| 82 | printk(KERN_ERR "VFS: Not enough space to compose quota message!\n"); | |
| 83 | err_out: | |
| 84 | kfree_skb(skb); | |
| 85 | } | |
| 86 | EXPORT_SYMBOL(quota_send_warning); | |
| 87 | ||
| 88 | static int __init quota_init(void) | |
| 89 | { | |
| 90 | if (genl_register_family("a_genl_family) != 0) | |
| 91 | printk(KERN_ERR | |
| 92 | "VFS: Failed to create quota netlink interface.\n"); | |
| 93 | return 0; | |
| 94 | }; | |
| 95 | ||
| 96 | module_init(quota_init); |