Re: [PATCH] common: rework _require_ext4_mkfs_feature

["Theodore Ts'o" <tytso@mit.edu>]

On Wed, Nov 15, 2017 at 11:56:55AM +1100, Dave Chinner wrote:
> Implement, like in mkfs.xfs, the "-N" flag (a.k.a "--dry-run").
> It does option parsing and geometry calculations, outputs the config
> that would be made, then exits before doing any actual IO. Hence we
> can check mkfs feature support on XFS, and only take the time to
> make a filesystem if we need to check that kernel support exists.

mke2fs has a -n option, but that's not what I'm trying to address.

Now that we want to *mount* the file system to check to see if the
kernel can support the file system feature, we can no longer use the
-n option.  And since the tests all need to create the file system
*anyway*, it seemed rather pointless to create it once, then do the
trial mount, and then creating the file system a second time.

      	     	      	       	   	       - Ted