Re: [PATCH/RFC] fscache/cachefiles versus btrfs

[NeilBrown <neilb@suse.de>]

[-- Attachment #1: Type: text/plain, Size: 1068 bytes --]

On Thu, 09 Apr 2015 10:23:08 +0100 David Howells <dhowells@redhat.com> wrote:

> NeilBrown <neilb@suse.de> wrote:
> 
> >  Is there a better way?  Could a better way be created?  Maybe
> >  SEEK_DATA_RELIABLE ??
> 
> fiemap() maybe?
> 
> > Also, if you do try to use fscache on btrfs with 3.19, then nothing gets
> > cached (as expected) and with a heavy load you can lose a race and get an
> > asserting fail in fscache_enqueue_operation
> 
> Do you have the patches here applied?
> 
> 	http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=fscache-fixes
> 

Do I don't.  I had looked through them and while they did seem to be
addressing similar sorts of races, nothing seems like an obvious match.
I haven't been able to reproduce the BUG_ON myself.  I only have a report
of it repeatedly affecting someone else:

  https://bugzilla.opensuse.org/show_bug.cgi?id=908706

I'll probably have to be happy with fixing usage on btrfs, and hope the other
bug is fixed already or doesn't become a problem.

Thanks,
NeilBrown

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 811 bytes --]