LP# 440522: FSCACHE modules not compiled in

[Christian Kujau]

On Tue, 9 Mar 2010 at 06:56, Tim Gardner wrote:
> The issue with NFS_FSCACHE in particular is that upstream support appears to
> be lukewarm, e.g., neither fscache.c or fscache-index.c has been touched since
> April 2009,

According to git-log, fs/nfs/fscache.c, has been touched in Sep 2009, Nov 
2009 and now in March again. fs/fscache has been touched in Nov 2009, the 
same goes for fs/cachefiles.

> yet the feature is still marked EXPERIMENTAL. 

As stated in the bugreport this flag has been removed upstream now, for 
2.6.34. However, as pointed out in the report and in [0] too, the 
EXPERIMENTAL flag is not considered useful any more by many upstream
developers. 

Furthermore, Ubuntu has enabled other EXPERIMENTAL features (e.g. 
CONFIG_FSCACHE, which only recently had its EXPERIMENTAL flag removed).

> Furthermore, NFS_FSCACHE cannot be built as a module

Indeed, the bug description should be changed :-)

> i.e., enabling this feature is going to affect the base NFS implementation.
> Until this situation changes, I'm not going into a long term release with
> an experimental feature in the mainline NFS path.

OpenSuse does it (since at least May 2005), Fedora does it too[1]. Again, 
I agree with Arjan[0] here: it's not EXPERIMENTAL just because someone
tagged it so. If not enabled, nothing changes from a user's perspective. 
If bugs are found (with caching enabled or not), they're likely NOT to 
occur only on Ubuntu machines but will have to be addressed upstream.

Please reconsider.

Thanks,
Christian.

[0] http://marc.info/?l=linux-nfs&m=126684776217594&w=2
[1] http://lwn.net/Articles/160122/
-- 
BOFH excuse #68:

only available on a need to know basis