Messages in this thread | | | Date | Tue, 29 Jun 2010 17:33:56 -0500 | Subject | Re: [PATCH 3/3] Add a pair of system calls to make extended file stats available | From | Steve French <> |
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On Tue, Jun 29, 2010 at 5:13 PM, Ulrich Drepper <drepper@gmail.com> wrote: > On Tue, Jun 29, 2010 at 13:03, David Howells <dhowells@redhat.com> wrote: >> Add a pair of system calls to make extended file stats available, including >> file creation time, inode version and data version where available through the >> underlying filesystem: > > If you add something like this you might want to integrate another > extension. This has been discussed a long time ago. In almost no > situation all the information is needed. Some of the pieces of > information returned by the syscall might be harder to collect than > other. It makes sense in such a situation to allow the caller to > specify what she is interested in. A bitmask of some sort. This was > brought up by the HPC people with gigantic filesystems. > > For this the syscall interface should have a parameter to specify what > is requested and the stat-like structure should have a field > specifying what is actually present. The latter bitmask must be a > superset of the former. > > Previous discussions centered around reusing the stat data structure > and somehow make it work. But no clean solution was found. If a new > structure is added anyway this could solve the issue.
That makes sense, especially for network file systems. NFSv4 protocol spec anticipates that:
"With the NFS version 4 protocol, the client is able query what attributes the server supports and construct requests with only those supported attributes (or a subset thereof)."
and we were talking about something similar for SMB2 Unix Extensions (posix extensions) at the last plugfest (for SMB2 kernel client to Samba) and testing events. -- Thanks,
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