[PATCH 0/4] change sb_writers to use percpu_rw_semaphore

[Oleg Nesterov <oleg@redhat.com>]

On top of "[PATCH 0/4] sb_write: lockdep fixes/cleanups" series.
Now that it was reviewed (thanks Jan!), let me send the actual
conversion.

1-2 add the simple percpu_rw_semaphore changes, this does not
conflict with the pending rcu_sync changes.

3/4 is really ugly but please see the changelog, this is the
temporary kludge to avoid the problems with other percpu-rwsem
changes routed via another tree.

4/4 looks simple and straightforward after the previous series.

Testing. Well, so far I only verified that ioctl(FIFREEZE) +
ioctl(FITHAW) seems to wors "as expected" on my testing machine
with ext3. So probably this needs more testing. Will try to do
this later. And after that we can hopefully remove the "trylock"
hack in __sb_start_write(), this series doesn't remove it.

But. I will be travelling till the end of the next week, and I'm
not sure I will have the internet access. So let me apologize in
advance if (most probably) I won't be able to reply until I return.

Please review.

Oleg.

 fs/super.c                    |  134 +++++++++++++++--------------------------
 include/linux/fs.h            |   22 +++----
 include/linux/percpu-rwsem.h  |   20 ++++++
 kernel/locking/percpu-rwsem.c |   13 ++++
 4 files changed, 89 insertions(+), 100 deletions(-)