xfsprogs: file write utility refactoring

Refactor the parts of mkfs and xfs_repair that open-code the process of
mapping disk space into files and writing data into them.  This will help
primarily with resetting of the realtime metadata, but is also used for
protofiles.
mkfs: use file write helper to populate files

Use the file write helper to write files into the filesystem.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
1 file changed