jfs: cache NULL when both default_acl and acl are NULL

default_acl and acl of newly created inode will be initiated
as ACL_NOT_CACHED in vfs function inode_init_always() and later
will be updated by calling xxx_init_acl() in specific filesystems.
Howerver, when default_acl and acl are NULL then they keep the value
of ACL_NOT_CACHED, this patch tries to cache NULL for acl/default_acl
in this case.

Signed-off-by: Chengguang Xu <[e-mail]>
Signed-off-by: Dave Kleikamp <[e-mail]>

fs/jfs/acl.c

···
 	if (default_acl) {
 		rc = __jfs_set_acl(tid, inode, ACL_TYPE_DEFAULT, default_acl);
 		posix_acl_release(default_acl);
+	} else {
+		inode->i_default_acl = NULL;
 	}
 
 	if (acl) {
 		if (!rc)
 			rc = __jfs_set_acl(tid, inode, ACL_TYPE_ACCESS, acl);
 		posix_acl_release(acl);
+	} else {
+		inode->i_acl = NULL;
 	}
 
 	JFS_IP(inode)->mode2 = (JFS_IP(inode)->mode2 & 0xffff0000) |