From: Andrew Lutomirski Subject: Re: How do I clear the append-only flag on symlinks? Date: Sat, 22 Oct 2011 01:57:45 -0700 Message-ID: References: <20111022051644.GD4196@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-ext4@vger.kernel.org To: "Ted Ts'o" Return-path: Received: from mail-iy0-f174.google.com ([209.85.210.174]:39063 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753048Ab1JVI6G convert rfc822-to-8bit (ORCPT ); Sat, 22 Oct 2011 04:58:06 -0400 Received: by iaek3 with SMTP id k3so5689295iae.19 for ; Sat, 22 Oct 2011 01:58:05 -0700 (PDT) In-Reply-To: <20111022051644.GD4196@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Oct 21, 2011 at 10:16 PM, Ted Ts'o wrote: > On Fri, Oct 21, 2011 at 11:07:51AM -0700, Andrew Lutomirski wrote: >> By means that are best not admitted to, I managed to mark a large >> chunk of my filesystem append-only, including symlinks. =A0I cleared= the >> flag from all the normal files and directories, but chattr and lsatt= r >> don't want to operate on symlinks. > > Yes. =A0So how did you set a whole chunk of your file system > append-only? I want to be able to write to shared, locked, writable mappings without sleeping. Updating file timestamps and stable pages get in the way. I was trying out an approach to fixing the file_update_call in do_wp_page using a new inode flag. Sadly, I figured out the hard way that 8196 is not actually a power of two. (My patch is also garbage for other reasons, but I'll email out a different approach as an RFC sometime soon.) If you have any ideas for how to handle stable pages other than carrying a patch to disable them, I'd love to hear it. The obvious approach of making a new writable copy of the page will involve pagecache internals that I'm not at all familiar with. > >> Any ideas on how to clear the append-only flags? =A0debug2fs is a li= ttle >> scary, and hacking e2fsprogs to allow operation on symlinks seems to >> affect symlink targets and not the symlinks themselves. > > I'd probably hack it into e2fsck, and let it offer to clear the > append-only flag on things that aren't regular files, on the theory > that they should have never been allowed to be set to begin with. > I'll take a look on Monday. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html