From: David Howells Subject: Re: [PATCH 3/3] Add a pair of system calls to make extended file stats available Date: Wed, 30 Jun 2010 00:29:52 +0100 Message-ID: <32322.1277854192@redhat.com> References: <20100629224844.GF4150@mail.oracle.com> <20100629200259.23196.81509.stgit@warthog.procyon.org.uk> <20100629200315.23196.68742.stgit@warthog.procyon.org.uk> <26026.1277851016@redhat.com> Cc: dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Ulrich Drepper , viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, smfrench-Re5JQEeQqe8AvxtiuMwx3w@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: Joel Becker Return-path: In-Reply-To: <20100629224844.GF4150-0Ol/1UON5C7fiIqoQl7HmA@public.gmane.org> Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org Joel Becker wrote: > The less variable length stuff the better, I think. At least, > for the stuff stat(2) already returns, you should have a fixed-size > structure. Even if I only pass the GIVE_ME_UIDS flag, I don't want to > have to deal with the variable size stuff until I've actually asked for > esoteric things. I'll know that the non-UIDS fields are garbage by the > fact that I didn't ask for them. I was thinking of the fixed length xstat struct plus appendable extensions to be defined later. I could live with each defined extension being of a fixed length, so for example, you set bit 20, and it adds, say, a 16-byte volume ID in the appropriate order, padded out appropriately for the filesystem. David