Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even when no change was necessary

[Bob Proulx]

Erik Rossen wrote:
> Jim Meyering wrote:
> > For chgrp (probably chown, too, at least in some cases), it's not
> > as obvious, since the current implementation does not stat files
> > before changing permissions.  So, to do what you want would involve
> > adding a stat call per file to get owner/group in order to avoid(maybe)
> > the offending ownership-changing syscall.  That would not be an
> > improvement.
> 
> As far as speed is concerned, you are right that an extra stat() would
> usually not improve matters.  (Would it be an enormous penalty?  I doubt
> it.)  But users of file integrity checking systems like myself will be
> grateful for the change of behavior.

You would be surprised how much performance can change when adding
extra stat calls.  Many filesystems such as networked filesystems are
extremely latency bound and those kinds of changes have a strong
negative impact upon them.

Bob