[PATCH 3/3] Add a pair of system calls to make extended file stats available
smfrench at gmail.com
Tue Jun 29 16:33:56 MDT 2010
On Tue, Jun 29, 2010 at 5:13 PM, Ulrich Drepper <drepper at gmail.com> wrote:
> On Tue, Jun 29, 2010 at 13:03, David Howells <dhowells at 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.
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