Re: [PATCH RFC 0/4] change sb_writers to use percpu_rw_semaphore

From: Oleg Nesterov
Date: Mon Jul 13 2015 - 18:44:24 EST


On 07/14, Dave Chinner wrote:
>
> [ Please cc linux-fsdevel@xxxxxxxxxxxxxxx on filesystem
> infrastructure changes! ]

OK, will do.

> On Mon, Jul 13, 2015 at 11:25:36PM +0200, Oleg Nesterov wrote:
> >
> > - sb_lockdep_release() and sb_lockdep_acquire() play with
> > percpu_rw_semaphore's internals.
> >
> > Trivial, we need a couple of new helper in percpu-rwsem.c.
>
> - try compiling XFS, watch it break on freeze lockdep
> annotations

Thanks a lot! I see. Still trivial, xfs can use the same helpers
rather the abuse lockdep directly.

> > - Most probably I missed something else, and I do not need
> > how to test.
>
> xfstests has many freeze related stress tests. IIRC, generic/068 is
> the test that historically causes the most problems for freeze
> infrastructure changes. You'll also need to test at least ext4, XFS
> and btrfs, because they all stress the freeze code differently.
> Testing XFS, in particular, is a good idea because it has several
> custom freeze tests that aren't run on any other filesystem type.

Thanks again.

Do you see something fundamentally wrong with this change?

Oleg.

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