[OpenAFS-devel] Q: pending Solaris changes that can potentially affect OpenAFS on Solaris

[Frank Batschulat (Home)]

On Fri, 16 Oct 2009 20:28:05 +0200, Dale Ghent <daleg@elemental.org> wrote:

> Thanks for the heads-up, Frank. Given the lack of reply since you sent
> this, I don't think anything immediately knows off thei top of their
> head, and I don't either. Investigation is in order.
>
> Are these changes happening under a specific PSARC that's in the open
> on arc.o.o ?

yes, there is, PSARC/2009/566

http://mail.opensolaris.org/pipermail/opensolaris-arc/2009-October/018617.html

> On Oct 9, 2009, at 12:32 PM, Frank Batschulat (Home) wrote:
>
>> friends,
>>
>> We're about to make some changes in the development release of
>> Solaris that will in due course be backported to Solaris 10 as well.
>>
>> We're trying to ensure that we won't break any unbundled file
>> systems.
>>
>> The changes are two-fold: an addition to the 'vfs_impl_t' and
>> a change to the behaviour of vfs_add()/vfs_list_add().
>>
>> http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/fs/vfs.c
>>
>> In the latter case, we will be forcibly allocating a 'vfs_impl_t' to
>> any
>> 'vfs_t' that has a NULL 'vfs_t->vfs_implp'.
>>
>> http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/sys/vfs.h
>>
>> Well-behaved file systems are passed by the generic kernel code
>> ( vfs.c:domount() )
>> a 'vfs_t' which they might modify in some way. Such file systems
>> will be unaffected.
>>
>> However we've seen file systems that might "allocate" their own
>> 'vfs_t'
>> and then insert it into the global list, probably through an existing
>> "interface" such as vfs_add() or vfs_list_add(). (NB. which is a bad
>> thing(TM))
>>
>> Such file systems might be a problem depending on how they initialise
>> 'vfs_t->vfs_implp' and how they insert the 'vfs_t' into the global
>> list
>> of vfs instances.
>>
>> I'm therefore keen to learn whether OpenAFS perhaps allocates its own
>> 'vfs_t' and, if so, what it then does with it.
>>
>> Can you please let us know if that may cause headaches on your end ?
>>
>> thanks!
>> --
>> frankB