diff --git a/fs/nfs_common/nfsacl.c b/fs/nfs_common/nfsacl.c
index ea382b75b26c..e2eaac14fd8e 100644
--- a/fs/nfs_common/nfsacl.c
+++ b/fs/nfs_common/nfsacl.c
@@ -42,7 +42,7 @@ struct nfsacl_encode_desc {
 };
 
 struct nfsacl_simple_acl {
-	struct posix_acl acl;
+	struct posix_acl_hdr acl;
 	struct posix_acl_entry ace[4];
 };
 
@@ -112,7 +112,8 @@ int nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
 	    xdr_encode_word(buf, base, entries))
 		return -EINVAL;
 	if (encode_entries && acl && acl->a_count == 3) {
-		struct posix_acl *acl2 = &aclbuf.acl;
+		struct posix_acl *acl2 =
+			container_of(&aclbuf.acl, struct posix_acl, hdr);
 
 		/* Avoid the use of posix_acl_alloc().  nfsacl_encode() is
 		 * invoked in contexts where a memory allocation failure is
@@ -177,7 +178,8 @@ bool nfs_stream_encode_acl(struct xdr_stream *xdr, struct inode *inode,
 		return false;
 
 	if (encode_entries && acl && acl->a_count == 3) {
-		struct posix_acl *acl2 = &aclbuf.acl;
+		struct posix_acl *acl2 =
+			container_of(&aclbuf.acl, struct posix_acl, hdr);
 
 		/* Avoid the use of posix_acl_alloc().  nfsacl_encode() is
 		 * invoked in contexts where a memory allocation failure is
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index e2d47eb1a7f3..62d497763e25 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -27,11 +27,16 @@ struct posix_acl_entry {
 };
 
 struct posix_acl {
-	refcount_t		a_refcount;
-	unsigned int		a_count;
-	struct rcu_head		a_rcu;
+	/* New members MUST be added within the struct_group() macro below. */
+	struct_group_tagged(posix_acl_hdr, hdr,
+		refcount_t		a_refcount;
+		unsigned int		a_count;
+		struct rcu_head		a_rcu;
+	);
 	struct posix_acl_entry	a_entries[] __counted_by(a_count);
 };
+static_assert(offsetof(struct posix_acl, a_entries) == sizeof(struct posix_acl_hdr),
+	      "struct member likely outside of struct_group_tagged()");
 
 #define FOREACH_ACL_ENTRY(pa, acl, pe) \
 	for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)