xfs_io: fix broken funshare_cmd usage

Create a funshare_cmd and use that to store information about the
xfs_io funshare command instead of overwriting the contents of
fzero_cmd.  This fixes confusing output like:

$ xfs_io -c 'fzero 2 3 --help' /
fzero: invalid option -- '-'
funshare off len -- unshares shared blocks within the range

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
1 file changed