fs: provide rcu-walk aware permission i_ops

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
diff --git a/fs/jfs/acl.c b/fs/jfs/acl.c
index 1057a49..e5de942 100644
--- a/fs/jfs/acl.c
+++ b/fs/jfs/acl.c
@@ -114,10 +114,14 @@
 	return rc;
 }
 
-int jfs_check_acl(struct inode *inode, int mask)
+int jfs_check_acl(struct inode *inode, int mask, unsigned int flags)
 {
-	struct posix_acl *acl = jfs_get_acl(inode, ACL_TYPE_ACCESS);
+	struct posix_acl *acl;
 
+	if (flags & IPERM_FLAG_RCU)
+		return -ECHILD;
+
+	acl = jfs_get_acl(inode, ACL_TYPE_ACCESS);
 	if (IS_ERR(acl))
 		return PTR_ERR(acl);
 	if (acl) {
diff --git a/fs/jfs/jfs_acl.h b/fs/jfs/jfs_acl.h
index 54e0755..f9285c4 100644
--- a/fs/jfs/jfs_acl.h
+++ b/fs/jfs/jfs_acl.h
@@ -20,7 +20,7 @@
 
 #ifdef CONFIG_JFS_POSIX_ACL
 
-int jfs_check_acl(struct inode *, int);
+int jfs_check_acl(struct inode *, int, unsigned int flags);
 int jfs_init_acl(tid_t, struct inode *, struct inode *);
 int jfs_acl_chmod(struct inode *inode);