Re: NFSv4/pNFS possible POSIX I/O API standards

[Andreas Dilger <adilger@clusterfs.com>]

On Dec 01, 2006  09:41 -0500, Trond Myklebust wrote:
> 'ls --color' and 'find' don't give a toss about most of the arguments
> from 'stat()'. They just want to know what kind of filesystem object
> they are dealing with. We already provide that information in the
> readdir() syscall via the 'd_type' field.

That is _almost_ true, except that "ls --color" does a stat anyways to
get the file mode (to set the "*" executable type) and the file blocks
(with -s) and the size (with -l) and the inode number (with -i).

In a clustered filesystem getting the inode number and mode is easily
done along with the uid/gid (for many kinds of "find") while getting
the file size may be non-trivial.

Just to be clear, I have no desire to include any kind of
"synchronization" semantics to readdirplus() that is also being discussed
in this thread.  Just the ability to bundle select stat info along with
the readdir information, and to allow stat to not return any unnecessary
info (in particular size, blocks, mtime) that may be harder to gather
on a clustered filesystem.

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.