Messages in this thread | | | Date | Fri, 14 Mar 2008 00:13:00 -0700 | From | Ulrich Drepper <> | Subject | Re: [RFC] Union mount readdir support in glibc |
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Al Viro wrote: > How about "the first entry returned by getdents(3) after open() is a whiteout > for e.g. '.'"? No fstat needed, zero impact for normal directories, > zero impact for any binaries on old kernels (where you wouldn't have > unions) and zero impact for old binaries on new kernels unless they > do getdents() on directory that happens to be a union.
Your definition of "zero impact" doesn't quite match mine. This would require significant changes.
> And no lockstep...
Of course there is lockstep. It is not under the application's control whether a directory is a union fs or not. Every implementation except a pure kernel implementation has this problem.
>> - - How does this work with NFS? > > It won't, kernel-side or done in userland.
Why wouldn't a kernel-side implementation work?
> Actually, do we really need it other than to 0 and to current position > (i.e. full rewind and a no-op)?
Ever heard of the little function "telldir"?
- -- ➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org
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