From: David Howells Subject: Re: [PATCH 3/3] xstat: Implement a requestable extra result to procure some inode flags [ver #4] Date: Mon, 05 Jul 2010 16:05:40 +0100 Message-ID: <4964.1278342340@redhat.com> References: <20100701235727.19035.84584.stgit@warthog.procyon.org.uk> <20100701235738.19035.21536.stgit@warthog.procyon.org.uk> Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org, samba-technical@lists.samba.org, linux-ext4@vger.kernel.org To: Andreas Dilger Return-path: Received: from mx1.redhat.com ([209.132.183.28]:37464 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753160Ab0GEPFs (ORCPT ); Mon, 5 Jul 2010 11:05:48 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: Andreas Dilger wrote: > I would say this should be a full-fledged member of struct xstat. I think > they are fairly standard (available on many filesystems today), and > requiring an ioctl to access them is unpleasant. Remember: adding them to xstat and kstat will use up three extra 64-bit words of stack at least if ecryptfs. Are they used often enough to justify this? > Yuck on the names. Why not stick with the "UF_" and "SF_" prefixes? Firstly, this is a quick and dirty example, primarily because I'd like someone to take a look at the mechanism. Secondly, because the flags I've added don't have UF_ and SF_ variants within Linux. > Since we don't need to keep _binary_ compatibility with these flag values > (only name portability) we can use the same flag values as the FS_*_FL > definitions in fs.h. No, you can't, because Linux doesn't have separate S and U variants. However, I'd be quite happy to just use the FS_*_FL, perhaps plus a couple of flags, and have userspace munge together the BSD-compatible st_flags. To that end, could we rearrange i_flags to match the ioctl? David