svn commit: r318736 - in head: cddl/lib/libzfs contrib/compiler-rt/lib/sanitizer_common contrib/openbsm/libbsm include lib/libarchive lib/libc/gen lib/libc/include lib/libc/sys lib/libkvm lib/libmi...

[Alan Somers]

On Tue, May 23, 2017 at 3:29 AM Konstantin Belousov <kib at freebsd.org> wrote:
>
> Author: kib
> Date: Tue May 23 09:29:05 2017
> New Revision: 318736
> URL: https://svnweb.freebsd.org/changeset/base/318736
>
> Log:
>   Commit the 64-bit inode project.
>
>   Extend the ino_t, dev_t, nlink_t types to 64-bit ints.  Modify
>   struct dirent layout to add d_off, increase the size of d_fileno
>   to 64-bits, increase the size of d_namlen to 16-bits, and change
>   the required alignment.  Increase struct statfs f_mntfromname[] and
>   f_mntonname[] array length MNAMELEN to 1024.
>
>   ABI breakage is mitigated by providing compatibility using versioned
>   symbols, ingenious use of the existing padding in structures, and
>   by employing other tricks.  Unfortunately, not everything can be
>   fixed, especially outside the base system.  For instance, third-party
>   APIs which pass struct stat around are broken in backward and
>   forward incompatible ways.
>
>   Kinfo sysctl MIBs ABI is changed in backward-compatible way, but
>   there is no general mechanism to handle other sysctl MIBS which
>   return structures where the layout has changed. It was considered
>   that the breakage is either in the management interfaces, where we
>   usually allow ABI slip, or is not important.
>
>   Struct xvnode changed layout, no compat shims are provided.
>
>   For struct xtty, dev_t tty device member was reduced to uint32_t.
>   It was decided that keeping ABI compat in this case is more useful
>   than reporting 64-bit dev_t, for the sake of pstat.
>
>   Update note: strictly follow the instructions in UPDATING.  Build
>   and install the new kernel with COMPAT_FREEBSD11 option enabled,
>   then reboot, and only then install new world.
>
>   Credits: The 64-bit inode project, also known as ino64, started life
>   many years ago as a project by Gleb Kurtsou (gleb).  Kirk McKusick
>   (mckusick) then picked up and updated the patch, and acted as a
>   flag-waver.  Feedback, suggestions, and discussions were carried
>   by Ed Maste (emaste), John Baldwin (jhb), Jilles Tjoelker (jilles),
>   and Rick Macklem (rmacklem).  Kris Moore (kris) performed an initial
>   ports investigation followed by an exp-run by Antoine Brodin (antoine).
>   Essential and all-embracing testing was done by Peter Holm (pho).
>   The heavy lifting of coordinating all these efforts and bringing the
>   project to completion were done by Konstantin Belousov (kib).
>
>   Sponsored by: The FreeBSD Foundation (emaste, kib)
>   Differential revision:        https://reviews.freebsd.org/D10439

What's the purpose of the new dirent.d_off field?  I can't find any
code that uses it.  I'm wondering if the fuse(4) module should set it
in order to work properly over NFS, or something.
-Alan