From: David Howells Subject: Re: [PATCH 0/3] Extended file stat functions Date: Tue, 29 Jun 2010 21:41:01 +0100 Message-ID: <23973.1277844061@redhat.com> References: <20100629200259.23196.81509.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, mcao-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org, aneesh.kumar-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, samba-technical-w/Ol4Ecudpl8XjKLYN78aQ@public.gmane.org, sjayaraman-l3A5Bk7waGM@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Steve French Return-path: In-Reply-To: Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org Steve French wrote: > How does a fs return an "unknown" value for one > (e.g. version field) ... 0 or -1 or ... Well, for the new creation time, inode version and data version fields,= the query_flags field has a bit for each that's set if the field contains a= value, and is clear if it doesn't. See the test program on patch 3. > One hole that this reminded me about is how to return the superblock > time granularity (for NFSv4 this is attribute 51 "time_delta" which > is called on a superblock not on a file). We run into time rounding > issues with Samba too. That sounds like something that should be accessible through statfs. B= ut it could be made accessible here too. It would also apply to FAT, which I believe has a 2s granularity. > > =A0(4) Should the inode number and data version number fields be 12= 8-bit? > This is tricky for SMB2, if you can also provide a device id (or an o= bject > id of some sort for the superblock) then 64 bit inode number is ok. A remote device ID? That would be possible. That could be used by AFS= to return the numeric volume ID (32 bits) and by NFS to return the FSID (1= 28 bits). Would you be using the VolumeGUID (128 bits) for SMB2? David