Re: [PATCH 2/2] xfs_io: don't count fsmaps before querying fsmaps

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Jul 05, 2021 at 04:25:27PM +0100, Christoph Hellwig wrote:
> On Fri, Jul 02, 2021 at 07:58:20PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> > 
> > There's a bunch of code in fsmap.c that tries to count the GETFSMAP
> > records so that it can size the fsmap array appropriately for the
> > GETFSMAP call.  It's pointless to iterate the entire result set /twice/
> > (unlike the bmap command where the extent count is actually stored in
> > the fs metadata), so get rid of the duplicate walk.
> 
> In otherwords:  just keep iterating over the records using the default
> chunk size instead of doing one call to find the size and then do
> a giant allocation and GETFSMAP call.

I'll paste this into the commit log, thanks.

--D

> I find the current commit log a little confusing, but the change itself
> looks good:
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>