[WIP] Debug tar failure

The symptom was:
> # ./test.sh --no-make
> tar: [..]/svn-repo: Cannot mkdir: Invalid cross-device link
> tar: [..]/svn-repo/db: Cannot mkdir: Invalid cross-device link
> tar: [..]/svn-repo/db/current: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/db/format: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/db/fs-type: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/db/min-unpacked-rev: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/db/revprops: Cannot mkdir: Invalid cross-device link
> tar: [..]/svn-repo/db/revprops/0: Cannot mkdir: Invalid cross-device link
> tar: [..]/svn-repo/db/revprops/0/0: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/db/revs: Cannot mkdir: Invalid cross-device link
> tar: [..]/svn-repo/db/revs/0: Cannot mkdir: Invalid cross-device link
> tar: [..]/svn-repo/db/revs/0/0: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/db/transactions: Cannot mkdir: Invalid cross-device link
> tar: [..]/svn-repo/db/txn-current: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/db/txn-current-lock: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/db/txn-protorevs: Cannot mkdir: Invalid cross-device link
> tar: [..]/svn-repo/db/uuid: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/db/write-lock: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/format: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/locks: Cannot mkdir: Invalid cross-device link
> tar: [..]/svn-repo/locks/db-logs.lock: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/locks/db.lock: Cannot open: Invalid cross-device link
> tar: [..]/svn-repo/README.txt: Cannot open: Invalid cross-device link
> tar: Exiting with failure status due to previous errors

Author: hartwork

test.sh

@@ -30,6 +30,27 @@ else
     make
 fi
 
+echo XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+tar --version
+echo XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+findmnt
+echo XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ls -lh
+echo XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+df -T .
+df -T "$PWD"
+df -T "$GITHUB_WORKSPACE"
+df -T /tmp
+echo XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+set -x
+echo hello > test/file
+tar -cf test.tar test
+tar -xf test.tar --one-top-level=out1
+tar -xf test.tar --one-top-level="$PWD/out2"
+echo XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+tar xvf test/base-fixture.tar --one-top-level="$PWD/base_fixture_tar_dir"
+exit 1
+
 if [ $# -eq 0 ]; then
     set -- test
 else