diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 5e325a4..8bd2135 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -78,7 +78,8 @@
 {
 	const struct posix_acl_entry *pa, *pe;
 	int state = ACL_USER_OBJ;
-	unsigned int id = 0;  /* keep gcc happy */
+	kuid_t prev_uid = INVALID_UID;
+	kgid_t prev_gid = INVALID_GID;
 	int needs_mask = 0;
 
 	FOREACH_ACL_ENTRY(pa, acl, pe) {
@@ -87,7 +88,6 @@
 		switch (pa->e_tag) {
 			case ACL_USER_OBJ:
 				if (state == ACL_USER_OBJ) {
-					id = 0;
 					state = ACL_USER;
 					break;
 				}
@@ -96,16 +96,17 @@
 			case ACL_USER:
 				if (state != ACL_USER)
 					return -EINVAL;
-				if (pa->e_id == ACL_UNDEFINED_ID ||
-				    pa->e_id < id)
+				if (!uid_valid(pa->e_uid))
 					return -EINVAL;
-				id = pa->e_id + 1;
+				if (uid_valid(prev_uid) &&
+				    uid_lte(pa->e_uid, prev_uid))
+					return -EINVAL;
+				prev_uid = pa->e_uid;
 				needs_mask = 1;
 				break;
 
 			case ACL_GROUP_OBJ:
 				if (state == ACL_USER) {
-					id = 0;
 					state = ACL_GROUP;
 					break;
 				}
@@ -114,10 +115,12 @@
 			case ACL_GROUP:
 				if (state != ACL_GROUP)
 					return -EINVAL;
-				if (pa->e_id == ACL_UNDEFINED_ID ||
-				    pa->e_id < id)
+				if (!gid_valid(pa->e_gid))
 					return -EINVAL;
-				id = pa->e_id + 1;
+				if (gid_valid(prev_gid) &&
+				    gid_lte(pa->e_gid, prev_gid))
+					return -EINVAL;
+				prev_gid = pa->e_gid;
 				needs_mask = 1;
 				break;
 
@@ -195,15 +198,12 @@
 		return ERR_PTR(-ENOMEM);
 
 	acl->a_entries[0].e_tag  = ACL_USER_OBJ;
-	acl->a_entries[0].e_id   = ACL_UNDEFINED_ID;
 	acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
 
 	acl->a_entries[1].e_tag  = ACL_GROUP_OBJ;
-	acl->a_entries[1].e_id   = ACL_UNDEFINED_ID;
 	acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
 
 	acl->a_entries[2].e_tag  = ACL_OTHER;
-	acl->a_entries[2].e_id   = ACL_UNDEFINED_ID;
 	acl->a_entries[2].e_perm = (mode & S_IRWXO);
 	return acl;
 }
@@ -224,11 +224,11 @@
                 switch(pa->e_tag) {
                         case ACL_USER_OBJ:
 				/* (May have been checked already) */
-				if (inode->i_uid == current_fsuid())
+				if (uid_eq(inode->i_uid, current_fsuid()))
                                         goto check_perm;
                                 break;
                         case ACL_USER:
-				if (pa->e_id == current_fsuid())
+				if (uid_eq(pa->e_uid, current_fsuid()))
                                         goto mask;
 				break;
                         case ACL_GROUP_OBJ:
@@ -239,7 +239,7 @@
                                 }
 				break;
                         case ACL_GROUP:
-                                if (in_group_p(pa->e_id)) {
+				if (in_group_p(pa->e_gid)) {
 					found = 1;
 					if ((pa->e_perm & want) == want)
 						goto mask;
diff --git a/fs/xattr.c b/fs/xattr.c
index 4d45b71..c111745 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -20,6 +20,7 @@
 #include <linux/fsnotify.h>
 #include <linux/audit.h>
 #include <linux/vmalloc.h>
+#include <linux/posix_acl_xattr.h>
 
 #include <asm/uaccess.h>
 
@@ -347,6 +348,9 @@
 			error = -EFAULT;
 			goto out;
 		}
+		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
+		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
+			posix_acl_fix_xattr_from_user(kvalue, size);
 	}
 
 	error = vfs_setxattr(d, kname, kvalue, size, flags);
@@ -450,6 +454,9 @@
 
 	error = vfs_getxattr(d, kname, kvalue, size);
 	if (error > 0) {
+		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
+		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
+			posix_acl_fix_xattr_to_user(kvalue, size);
 		if (size && copy_to_user(value, kvalue, error))
 			error = -EFAULT;
 	} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
diff --git a/fs/xattr_acl.c b/fs/xattr_acl.c
index 69d06b0..bf472ca 100644
--- a/fs/xattr_acl.c
+++ b/fs/xattr_acl.c
@@ -9,7 +9,65 @@
 #include <linux/fs.h>
 #include <linux/posix_acl_xattr.h>
 #include <linux/gfp.h>
+#include <linux/user_namespace.h>
 
+/*
+ * Fix up the uids and gids in posix acl extended attributes in place.
+ */
+static void posix_acl_fix_xattr_userns(
+	struct user_namespace *to, struct user_namespace *from,
+	void *value, size_t size)
+{
+	posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
+	posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
+	int count;
+	kuid_t uid;
+	kgid_t gid;
+
+	if (!value)
+		return;
+	if (size < sizeof(posix_acl_xattr_header))
+		return;
+	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
+		return;
+
+	count = posix_acl_xattr_count(size);
+	if (count < 0)
+		return;
+	if (count == 0)
+		return;
+
+	for (end = entry + count; entry != end; entry++) {
+		switch(le16_to_cpu(entry->e_tag)) {
+		case ACL_USER:
+			uid = make_kuid(from, le32_to_cpu(entry->e_id));
+			entry->e_id = cpu_to_le32(from_kuid(to, uid));
+			break;
+		case ACL_GROUP:
+			gid = make_kgid(from, le32_to_cpu(entry->e_id));
+			entry->e_id = cpu_to_le32(from_kuid(to, uid));
+			break;
+		default:
+			break;
+		}
+	}
+}
+
+void posix_acl_fix_xattr_from_user(void *value, size_t size)
+{
+	struct user_namespace *user_ns = current_user_ns();
+	if (user_ns == &init_user_ns)
+		return;
+	posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
+}
+
+void posix_acl_fix_xattr_to_user(void *value, size_t size)
+{
+	struct user_namespace *user_ns = current_user_ns();
+	if (user_ns == &init_user_ns)
+		return;
+	posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
+}
 
 /*
  * Convert from extended attribute to in-memory representation.
@@ -50,12 +108,21 @@
 			case ACL_GROUP_OBJ:
 			case ACL_MASK:
 			case ACL_OTHER:
-				acl_e->e_id = ACL_UNDEFINED_ID;
 				break;
 
 			case ACL_USER:
+				acl_e->e_uid =
+					make_kuid(&init_user_ns,
+						  le32_to_cpu(entry->e_id));
+				if (!uid_valid(acl_e->e_uid))
+					goto fail;
+				break;
 			case ACL_GROUP:
-				acl_e->e_id = le32_to_cpu(entry->e_id);
+				acl_e->e_gid =
+					make_kgid(&init_user_ns,
+						  le32_to_cpu(entry->e_id));
+				if (!gid_valid(acl_e->e_gid))
+					goto fail;
 				break;
 
 			default:
@@ -89,9 +156,22 @@
 	ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
 
 	for (n=0; n < acl->a_count; n++, ext_entry++) {
-		ext_entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
-		ext_entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
-		ext_entry->e_id   = cpu_to_le32(acl->a_entries[n].e_id);
+		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
+		ext_entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+		ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
+		switch(acl_e->e_tag) {
+		case ACL_USER:
+			ext_entry->e_id =
+				cpu_to_le32(from_kuid(&init_user_ns, acl_e->e_uid));
+			break;
+		case ACL_GROUP:
+			ext_entry->e_id =
+				cpu_to_le32(from_kgid(&init_user_ns, acl_e->e_gid));
+			break;
+		default:
+			ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
+			break;
+		}
 	}
 	return real_size;
 }