[PATCH 2/2] xfs: fix splice/direct-IO deadlock

[Christoph Hellwig]

On Wed, Nov 28, 2012 at 01:12:48PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner at redhat.com>
> 
> lockdep reports splice vs direct-io write lock inversions due to
> generic_file_splice_write() taking the inode->i_mutex inside
> XFS_IOLOCK_EXCL context. These lock contexts are inverted, hence can
> deadlock.  Remove the XFS_IOLOCK_EXCL locking context from the outer
> function and drive it inwards to the actor function that only locks
> the inode when the lock is really needed,

punctuation?

Otherwise the patch looks fine, but I'd love to understand why the
generic code thes te I_MUTEX_CHILD annotation and we can get away
without it.

Also can you add a testcase for this to xfstests?