Re: [PATCH, RFC] mkfs.xfs: go into multidisk mode when geometry is on cmdline

Christoph Hellwig
2012-11-21T09:54:28Z

On Tue, Nov 20, 2012 at 10:34:29AM -0600, Eric Sandeen wrote:
> So now for a ~5T fs, for example, we'd make several more
> AGs:
>
> # truncate --size=5t fsfile
> # mkfs.xfs -N -d su=128k,sw=8 fsfile | grep agcount
> meta-data=fsfile isize=256 agcount=5, agsize=268435424 blks
> # mkfs/mkfs.xfs -N -d su=128k,sw=8 fsfile | grep agcount
> meta-data=fsfile isize=256 agcount=32, agsize=41943008 blks

Can you add this to xfstests, please?

> TBH, though, is there ever any value in treating a very large
> fs as "!multidisk?" When would we ever want to pretend that
> a 16T filesystem doesn't have a lot of spindles behind it?

Not now, but I'm pretty sure we'll get there not too soon in the
future.

> + } else if (daflag) /* User-specified AG count */
> + agsize = dblocks / agcount + (dblocks % agcount != 0);
> + else
> + calc_default_ag_geometry(blocklog, dblocks,
> + dsunit | dswidth, &agsize, &agcount);
> +

I know the code was just moved, but can you add braces to the else if
constructs so that the whole if else if else has consistent bracing?