/tmp might be small, might not support files larger than 2GB,
etc, so trying to host loopback images of 100GB filesystems
will break in some situations. We should use $TEST_DIR for the
images.
Note: remounting of loopback images has a major bug (in mount)
that "leaks" loopback device references. Hence all the hackery
with losetup to work around this.
Merge of master-melb:xfs-cmds:31169a by kenmcd.
Don't use /tmp for hosting loopback images
this is because $tmp.source_dir is not an empty dir.
This change recursively deletes everything in $tmp.source_dir.
Not required for $tmp.loop as it is used as a loopback mountpoint.
the ignore external MKFS_OPTIONS change is no longer required,
as _scratch_mkfs_xfs now handles conflicting options.
Merge of master-melb:xfs-cmds:28863a by kenmcd.
cleanup tmp and don't kill mkfs options