Filesystem ABI breakage on RELENG_6 coming

[Ken Smith]

Normally FreeBSD as a project tries very hard to make sure there is no
API or ABI breakage on a branch once it is declared 'stable'.  We have
an upcoming MFC to RELENG_6 that will unfortunately cause some ABI
breakage in filesystem modules.  This MFC when combined with a few
others fixes severe issues seen with filesystem snapshots.  We feel the
benefits outweigh the potential hassle people may have as a result of
this ABI breakage.  In particular note that it is only an in-kernel data
structure that is changing, nothing in the filesystem data structures
stored on disk (or elsewhere) is affected.

The commit, to be done some time Monday, will introduce a new bop,
bop_bdflush, to struct buf_ops in sys/sys/bufobj.h.  Only people using
filesystems that are not part of the baseline system (e.g. perhaps a
filesystem or something that acts like a filesystem from the ports
collection) should notice any issues.  If you support your own
filesystem of some sort you can take a look at the changes that get done
as part of this commit to the supported filesystems for guidance on what
you may need to add.  The commit will be done by the user "kib" to
RELENG_6.

This will only affect users of RELENG_6 short-term.  It will be part of
FreeBSD 6.3 and warnings about this will be in the release notes for
that.

-- 
                                                Ken Smith
- From there to here, from here to      |       kensmith at cse.buffalo.edu
  there, funny things are everywhere.   |
                      - Theodore Geisel |

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 187 bytes
Desc: This is a digitally signed message part
Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20070610/be63b661/attachment.pgp