Non-MPSAFE filesystems de-orbit burn schedule

This page documents proposed schedules for removing infrastructure for non-MPSAFE VFS components and filesystems.

This macro is used in order to conditionally acquire/drop/assert Giant lock in VFS layer, based on the MPSAFETY of the filesystem to be dealt with. The major goal of the project is to make it irrelevant, which means, for instance, locking all the already non-mpsafe filesystems and later on strip off the compat stuff.

Date	Done	Event
27 August 2011	Yes	Post MPSAFE VFS plan to arch@.
08 November 2011	Yes	Add VFS_ALLOW_NONMPSAFE kernel option and make it the default.
06 March 2012	Yes	Remove VFS_ALLOW_NONMPSAFE as the default kernel config.
13 October 2012	Yes	FUSE import into base.
22 October 2012	Yes	Disconnect non-mpsafe filesystems from the tree and remove the Giant-related code.
01 March 2013	Yes	Garbage collect in-tree non-mpsafe filesystems code.

Filesystem
CD9660FS
DevFS
Ext2FS
FdescFS
FifoFS
MSDOSFS
NFS Client
NFS Server
NullFS
PseudoFS
ProcFS
ReiserFS
SmbFS
TmpFS
UDF
UFS
UnionFS
ZFS

Filesystem	Owner	State
CodaFS	rwatson	Removed
HPFS		Removed
NtFS		Removed
NwFS*		Removed
PortalFS		Removed
XFS		Removed

* Please note that locking nwfs would also require to lock netncp components. Other operating systems got very good results in this (like MacOSX and Solaris) already.

As some of the current filesystems have a very poor in-kernel support but they are actually very useful (with the most notable case being NTFS), in order to not loose their support, we will import in the kernel and actively maintain the FUSE module. At this present stage, most of the bugs from the port seems addressed. Please refer to the following e-mails:

http://lists.freebsd.org/pipermail/freebsd-fs/2012-September/015180.html

http://lists.freebsd.org/pipermail/freebsd-fs/2012-September/015179.html