[PATCH 1/2] xfs: prevent recursion in xfs_buf_iorequest

[Dave Chinner]

On Mon, Jul 02, 2012 at 06:00:04AM -0400, Christoph Hellwig wrote:
> If the b_iodone handler is run in calling context in xfs_buf_iorequest we
> can run into a recursion where xfs_buf_iodone_callbacks keeps calling back
> into xfs_buf_iorequest because an I/O error happened, which keeps calling
> back into xfs_buf_iorequest.  This chain will usually not take long
> because the filesystem gets shut down because of log I/O errors, but even
> over a short time it can cause stack overflows if run on the same context.
> 
> As a short term workaround make sure we always call the iodone handler in
> workqueue context.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>

Looks fine - final completion from io submission is a rare case so
this shouldn't cause issues....

Reviewed-by: Dave Chinner <dchinner at redhat.com>

-- 
Dave Chinner
david at fromorbit.com