On Tue, Jun 21, 2022 at 12:33:04PM -0500, Linus Torvalds wrote: > On Tue, Jun 21, 2022 at 9:15 AM Christian Brauner <brauner@xxxxxxxxxx> wrote: > > > > The other nice effect is that filesystems like overlayfs don't need to > > care about idmappings explicitly anymore and can simply set up struct > > iattr accordingly directly. > > Btw, do we have any actual tests for this situation? Absolutely! In fact, I made it so that the whole xfstests testsuite can be run on top of idmapped mounts with overlayfs: FSTYP=xfs export TEST_DEV=/dev/sda3 export SCRATCH_DEV=/dev/sda4 export TEST_DIR=/mnt/test export SCRATCH_MNT=/mnt/scratch export IDMAPPED_MOUNTS=true sudo ./check -overlay from the README I added: - set IDMAPPED_MOUNTS=true to run all tests on top of idmapped mounts. While this option is supported for all filesystems currently only -overlay is expected to run without issues. For other filesystems additional patches and fixes to the test suite might be needed. That's __in addition__ to the whole idmapped mounts testsuite which is part of xfstests and which also covers overlayfs (e.g. in generic/692).
