[PATCH V2] xfs: create helper for bmap finish & trans join in attr code

[Christoph Hellwig]

On Fri, Nov 13, 2015 at 07:12:31AM +1100, Dave Chinner wrote:
> On Thu, Nov 12, 2015 at 08:58:01AM -0800, Christoph Hellwig wrote:
> > I think the problem here is simply that our interfaces suck.
> > xfs_trans_roll really needs to rejoin any inode to the new transaction
> > to that was joined to the previous one.  Once we've fixed that we can
> > get rid of the silly committed arguments and everyone will be happy.
> 
> xfs_trans_roll is not specifically for rolling transactions with
> locked inodes in them. We could use it for any object that needs
> multiple transactions to modify. e.g. we could roll transactions
> across an AGF (using hold+join) so that it remains locked across
> multiple allocation/free transactions.

xfs_trans_roll already logs the inode core, which requires the
inode to be attached to the transaction.  While I could see the
point of moving this out of the core __xfs_trans_roll into an
xfs_trans_roll_inode helper we might as well follow the current
interface for now.