2 files changed, 133 insertions, 1 deletions
diff --git a/fs/quota/Makefile b/fs/quota/Makefile
index 5f9e9e276af0..c66c37cdaa39 100644
--- a/fs/quota/Makefile
+++ b/fs/quota/Makefile
@@ -2,6 +2,6 @@ obj-$(CONFIG_QUOTA)		+= dquot.o
 obj-$(CONFIG_QFMT_V1)		+= quota_v1.o
 obj-$(CONFIG_QFMT_V2)		+= quota_v2.o
 obj-$(CONFIG_QUOTA_TREE)	+= quota_tree.o
-obj-$(CONFIG_QUOTACTL)		+= quota.o
+obj-$(CONFIG_QUOTACTL)		+= quota.o kqid.o
 obj-$(CONFIG_QUOTACTL_COMPAT)	+= compat.o
 obj-$(CONFIG_QUOTA_NETLINK_INTERFACE)	+= netlink.o
diff --git a/fs/quota/kqid.c b/fs/quota/kqid.c
new file mode 100644
index 000000000000..2f97b0e2c501
--- /dev/null
+++ b/fs/quota/kqid.c
@@ -0,0 +1,132 @@
+#include <linux/fs.h>
+#include <linux/quota.h>
+#include <linux/export.h>
+
+/**
+ *	qid_eq - Test to see if to kquid values are the same
+ *	@left: A qid value
+ *	@right: Another quid value
+ *
+ *	Return true if the two qid values are equal and false otherwise.
+ */
+bool qid_eq(struct kqid left, struct kqid right)
+{
+	if (left.type != right.type)
+		return false;
+	switch(left.type) {
+	case USRQUOTA:
+		return uid_eq(left.uid, right.uid);
+	case GRPQUOTA:
+		return gid_eq(left.gid, right.gid);
+	case PRJQUOTA:
+		return projid_eq(left.projid, right.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(qid_eq);
+
+/**
+ *	qid_lt - Test to see if one qid value is less than another
+ *	@left: The possibly lesser qid value
+ *	@right: The possibly greater qid value
+ *
+ *	Return true if left is less than right and false otherwise.
+ */
+bool qid_lt(struct kqid left, struct kqid right)
+{
+	if (left.type < right.type)
+		return true;
+	if (left.type > right.type)
+		return false;
+	switch (left.type) {
+	case USRQUOTA:
+		return uid_lt(left.uid, right.uid);
+	case GRPQUOTA:
+		return gid_lt(left.gid, right.gid);
+	case PRJQUOTA:
+		return projid_lt(left.projid, right.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(qid_lt);
+
+/**
+ *	from_kqid - Create a qid from a kqid user-namespace pair.
+ *	@targ: The user namespace we want a qid in.
+ *	@kuid: The kernel internal quota identifier to start with.
+ *
+ *	Map @kqid into the user-namespace specified by @targ and
+ *	return the resulting qid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	If @kqid has no mapping in @targ (qid_t)-1 is returned.
+ */
+qid_t from_kqid(struct user_namespace *targ, struct kqid kqid)
+{
+	switch (kqid.type) {
+	case USRQUOTA:
+		return from_kuid(targ, kqid.uid);
+	case GRPQUOTA:
+		return from_kgid(targ, kqid.gid);
+	case PRJQUOTA:
+		return from_kprojid(targ, kqid.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(from_kqid);
+
+/**
+ *	from_kqid_munged - Create a qid from a kqid user-namespace pair.
+ *	@targ: The user namespace we want a qid in.
+ *	@kqid: The kernel internal quota identifier to start with.
+ *
+ *	Map @kqid into the user-namespace specified by @targ and
+ *	return the resulting qid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	Unlike from_kqid from_kqid_munged never fails and always
+ *	returns a valid projid.  This makes from_kqid_munged
+ *	appropriate for use in places where failing to provide
+ *	a qid_t is not a good option.
+ *
+ *	If @kqid has no mapping in @targ the kqid.type specific
+ *	overflow identifier is returned.
+ */
+qid_t from_kqid_munged(struct user_namespace *targ, struct kqid kqid)
+{
+	switch (kqid.type) {
+	case USRQUOTA:
+		return from_kuid_munged(targ, kqid.uid);
+	case GRPQUOTA:
+		return from_kgid_munged(targ, kqid.gid);
+	case PRJQUOTA:
+		return from_kprojid_munged(targ, kqid.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(from_kqid_munged);
+
+/**
+ *	qid_valid - Report if a valid value is stored in a kqid.
+ *	@qid: The kernel internal quota identifier to test.
+ */
+bool qid_valid(struct kqid qid)
+{
+	switch (qid.type) {
+	case USRQUOTA:
+		return uid_valid(qid.uid);
+	case GRPQUOTA:
+		return gid_valid(qid.gid);
+	case PRJQUOTA:
+		return projid_valid(qid.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(qid_valid);