On Wed, Apr 15, 2020 at 10:42 PM Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > On Wed, Apr 15, 2020 at 07:27:43PM +0300, Amir Goldstein wrote: > > On Wed, Apr 15, 2020 at 6:30 PM Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > > > > > On Wed, Apr 15, 2020 at 03:01:34PM +0300, Amir Goldstein wrote: > > > > The following environment variables are supported: > > > > > > > > UNIONMOUNT_BASEDIR - base dir for --samefs (default: /base) > > > > UNIONMOUNT_UPPERDIR - upper layer root path (default: /upper) > > > > UNIONMOUNT_LOWERDIR - lower layer root path (default: /lower) > > > > UNIONMOUNT_MNTPOINT - mount point for tests (default: /mnt) > > > > > > > > User provided paths for base/lower/upper should point at a pre-mounted > > > > filesystem, whereas tmpfs instances will be created on default paths. > > > > > > > > This is going to be used for running unionmount tests from xfstests. > > > > > > Hi Amir, > > > > > > I don't understand this testsuite code. So I will ask. > > > > > > What's base dir? > > > > Before these changes, with option --samefs, tmpfs is mounted > > at /base, overlay lowerdir is /base/lower and upperdir is /base/upper. > > After these changes, /base can be substituted with any pre mounted > > filesystem path. > > If I can specify lower and upper root, then why do I need to specify > base directory. User can put lower, upper either on samefs or different > fs as need be. > > IOW, either I need to specify base dir, so that lower and upper can > be setup by testsuite automatically. Or I need to specify lower and > upper and then base should not matter. > > What am I missing. > Not much, as it stands, with option --samefs, UNIONMOUNT_BASEDIR is used and without --samefs UNIONMOUNT_LOWERDIR and UNIONMOUNT_UPPERDIR used instead. I agree that this a bit lame and non intuitive way to configure. The reason for explicit --samefs option (vs. providing upper and lower root from same fs) is, again, for the test sanity checks which differ for is_samefs() case. I think what I will do is I will get rid of UNIONMOUNT_UPPERDIR because this name is a bit confusing. It is not the overlay upperdir, it is the grandfather of upperdir/workdir. So I might as well call this config UNIONMOUNT_BASEDIR and use it also as the parent of lowerdir in --samefs tests. The config UNIONMOUNT_LOWERDIR will remain, but it will only be relevant to tests without --samefs. IOW, you won't need the fstab bind mount trick and you won't need to use the magic suffix "lower_layer" anymore. You could set: UNIONMOUNT_BASEDIR=/mnt/virtiofs to run --ov --samefs --verify tests. If you want to run test with virtio fs as upper (single or multi layers) and lower as another fs, you could additionally set: UNIONMOUNT_LOWERDIR=/mnt/anotherfs and run --ov --verify tests. Thanks for the feedback! Amir.
