Re: [PATCH] Remove DIO_OWN_LOCKING

[David Chinner <dgc@sgi.com>]

On Thu, Oct 12, 2006 at 07:56:38PM -0500, Russell Cattelan wrote:
> While trying to fix up GFS2 directio and reading through the code
> involving the various lock flags I discovered the DIO_OWN_LOCKING 
> flag is no longer used.
>  
> XFS recently changed it xfs_vm_direct_IO function to call
> blockdev_direct_IO_no_locking for reads and
> blockdev_direct_IO_own_locking
> for writes. But DIO_OWN_LOCKING is only used in the direct IO read case
> so effectively the flag is never checked an therefore can probably be
> removed.

NACK.

This breaks XFS direct writes - the DIO_OWN_LOCKING flag has meaning
for direct writes even though a simple grep doesn't give you any
hits. get_more_blocks() sets the create flag unconditionally on
writes when DIO_OWN_LOCKING is set, and this is needed for XFS to be
able to allocate underlying blocks if the direct write is over a
hole or past EOF.

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group