Initial import

1 files changed, 109 insertions, 0 deletions

diff --git a/fs/quota/netlink.c b/fs/quota/netlink.c
new file mode 100644
index 000000000..bb2869f5d
--- /dev/null
+++ b/fs/quota/netlink.c
@@ -0,0 +1,109 @@
+
+#include <linux/cred.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/quotaops.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+static const struct genl_multicast_group quota_mcgrps[] = {
+	{ .name = "events", },
+};
+
+/* Netlink family structure for quota */
+static struct genl_family quota_genl_family = {
+	/*
+	 * Needed due to multicast group ID abuse - old code assumed
+	 * the family ID was also a valid multicast group ID (which
+	 * isn't true) and userspace might thus rely on it. Assign a
+	 * static ID for this group to make dealing with that easier.
+	 */
+	.id = GENL_ID_VFS_DQUOT,
+	.hdrsize = 0,
+	.name = "VFS_DQUOT",
+	.version = 1,
+	.maxattr = QUOTA_NL_A_MAX,
+	.mcgrps = quota_mcgrps,
+	.n_mcgrps = ARRAY_SIZE(quota_mcgrps),
+};
+
+/**
+ * quota_send_warning - Send warning to userspace about exceeded quota
+ * @qid: The kernel internal quota identifier.
+ * @dev: The device on which the fs is mounted (sb->s_dev)
+ * @warntype: The type of the warning: QUOTA_NL_...
+ *
+ * This can be used by filesystems (including those which don't use
+ * dquot) to send a message to userspace relating to quota limits.
+ *
+ */
+
+void quota_send_warning(struct kqid qid, dev_t dev,
+			const char warntype)
+{
+	static atomic_t seq;
+	struct sk_buff *skb;
+	void *msg_head;
+	int ret;
+	int msg_size = 4 * nla_total_size(sizeof(u32)) +
+		       2 * nla_total_size(sizeof(u64));
+
+	/* We have to allocate using GFP_NOFS as we are called from a
+	 * filesystem performing write and thus further recursion into
+	 * the fs to free some data could cause deadlocks. */
+	skb = genlmsg_new(msg_size, GFP_NOFS);
+	if (!skb) {
+		printk(KERN_ERR
+		  "VFS: Not enough memory to send quota warning.\n");
+		return;
+	}
+	msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
+			&quota_genl_family, 0, QUOTA_NL_C_WARNING);
+	if (!msg_head) {
+		printk(KERN_ERR
+		  "VFS: Cannot store netlink header in quota warning.\n");
+		goto err_out;
+	}
+	ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID,
+			  from_kqid_munged(&init_user_ns, qid));
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID,
+			  from_kuid_munged(&init_user_ns, current_uid()));
+	if (ret)
+		goto attr_err_out;
+	genlmsg_end(skb, msg_head);
+
+	genlmsg_multicast(&quota_genl_family, skb, 0, 0, GFP_NOFS);
+	return;
+attr_err_out:
+	printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
+err_out:
+	kfree_skb(skb);
+}
+EXPORT_SYMBOL(quota_send_warning);
+
+static int __init quota_init(void)
+{
+	if (genl_register_family(&quota_genl_family) != 0)
+		printk(KERN_ERR
+		       "VFS: Failed to create quota netlink interface.\n");
+	return 0;
+};
+
+module_init(quota_init);