The state of Giant lock in the file systems?

[Antony Mawer]

On Tue, Nov 9, 2010 at 2:28 AM, Ivan Voras <ivoras at freebsd.org> wrote:
> On 8 November 2010 16:10, Kostik Belousov <kostikbel at gmail.com> wrote:
>
>> I already claimed several times that I will remove VFS_LOCK_GIANT
>> after smbfs is locked. Patch for removal is sitting in my repository
>> for almost a year.
>
> Ok, I've made a little table here:
>
> http://wiki.freebsd.org/MPSAFE_VFS

FYI - NWFS is still functional in 8.x (there are some minor but
annoying bugs, e.g. the root node path resolution occasionally trips
over itself causing the mount point to become inaccessible, but that's
been there since 4.x days), and I am happy to test any locking changes
to it.

>From memory NWFS and SMBFS share similar locking strategies so what
gets done to one typically gets applied to the other. This got hit
early in the 6.0 beta series where SMBFS had VFS locking changes which
hadn't been applied to NWFS. On that occasion we were able to work
with truckman@ to isolate the problem and get the right locking
changes made in time for 6.0's release.

On the SMBFS front, it's largely unmaintained as well (sadly) -- there
are patches to add Unicode support to SMBFS which have been floating
around since 2005, but so far they have (to my knowledge) never seen
any reviews:

http://people.freebsd.org/~imura/kiconv/

SMBFS and NWFS both share a lot of similar designs in terms of their
FreeBSD implementations due to being both implemented by the same
developer (bp@).

--Antony