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Message-ID: <16857.60781.615644.171434@samba.org>
Date: Tue, 4 Jan 2005 12:12:13 +1100
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Michael B Allen <mba2000@ioplex.com>, sfrench@samba.org,
       linux-ntfs-dev@lists.sourceforge.net, samba-technical@lists.samba.org,
       aia21@cantab.net, hirofumi@mail.parknet.co.jp,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: FAT, NTFS, CIFS and DOS attributes
In-Reply-To: <41D9EA09.8010302@zytor.com>
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	<54479.199.43.32.68.1104794772.squirrel@li4-142.members.linode.com>
	<41D9D65D.7050001@zytor.com>
	<16857.57572.25294.431752@samba.org>
	<41D9E23A.4010608@zytor.com>
	<16857.58819.311223.845400@samba.org>
	<41D9EA09.8010302@zytor.com>
Reply-To: tridge@samba.org
From: tridge@samba.org
Sender: linux-kernel-owner@vger.kernel.org
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 > The slightly stronger reason is basically the same reason why we don't 
 > stuff a bunch of things into a struct stat and call a single system call 
 > to change a bunch of attributes

yes, and if we want this to be a good API then we'd use something like
a bitmask to indicate what fields to update so we can update them in
groups in a raceless fashion, but that would require that the kernel
understand the internals of these structures. I didn't have that
luxury, so I grouped them in the way that best matched the common use
of the attributes.

 > you don't want to have to change them all every time, and by
 > putting them all in the same structure that's your only option,
 > since setxattr() doesn't allow you to mask and merge.

can you tell me who you imagining will be using these attributes apart
from Samba, Wine and backup/restore apps? 

 > 
 > Incidentally, the document you pointed me to wasn't clear on the 
 > endianness convention.

It's little-endian NDR. For a full description of NDR in all its gory
details see http://www.opengroup.org/onlinepubs/9629399/chap14.htm

NDR seems like overkill at first, until you start to look at security
descriptors. They are very complex beasts, and using IDL/NDR makes it
much easier (in fact, security descriptors need some minor
enhancements to NDR to encode them the same way windows does).

Cheers, Tridge
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