Re: [PATCH 0/2] splice: i_mutex vs splice write deadlock V2

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Mon, Aug 08, 2011 at 04:45:25PM +1000, Dave Chinner wrote:
> generic_file_splice_write() takes the inode->i_mutex after the
> filesystem has taken whatever locks it needs to ensure sanity.
> however, this typically violates the locking order of filesystems
> with their own locks in that the order is usually i_mutex ->
> filesystem lock.
> 
> XFS is such a case, and generic_file_splice_write() is generating
> lockdep warnings because of lock inversions between the
> inode->i_mutex and the XFS_I(inode)->i_iolock. There is also a
> reported case of fio causing a deadlock when it mixes IO types
> (e.g. splice vs direct IO).

Another case is ocfs2, which looks like a perfect candidate to be
converted over to your infrastructure.