Re: [PATCH V2] xfs: truncate_setsize should be outside transactions

[Dave Chinner <david@xxxxxxxxxxxxx>]

On Sat, May 03, 2014 at 08:16:01AM -0700, Christoph Hellwig wrote:
> On Sat, May 03, 2014 at 09:23:39AM +1000, Dave Chinner wrote:
> > before we get to the transaction that can fail:
> > block_truncate_page() zeroes the tail of the page cache page. Hence
> > if the transaction reservation fails, we've already trashed the file
> > data - we may as well finish off the job and at least make it look
> > like the truncate succeeded from a user point of view. They then get
> > a ENOMEM error (only non-fatal error that can come from
> > xfs_trans_reserve) and try the truncate again....
> 
> I don't think we can even get the ENOMEM.

We can - we pass KM_MAYFAIL to xlog_ticket_alloc() from
xfs_log_reserve().

> But yeah, I guess
> we want something like the old version, with comments explaining exactly
> we we have this order.

I'll send another version of the first patch with an expanded
comment.

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx