lib/repo: Don't syncfs or fsync() dirs if fsync opt is disabled

There are use cases for not syncing at all; think build cache repos, etc. Let's
be consistent here and make sure if fsync is disabled we do no sync at all.

I chose this opportunity to add tests using the shiny new strace fault
injection.  I can forsee using this for a lot more things, so I made
the support for detecting things generic.

Related: https://github.com/ostreedev/ostree/issues/1184

Closes: #1186
Approved by: jlebon

1 files changed, 23 insertions, 0 deletions

diff --git a/tests/libtest.sh b/tests/libtest.sh
index 5017abea..2b30e654 100755
--- a/tests/libtest.sh
+++ b/tests/libtest.sh
@@ -543,6 +543,29 @@ skip_without_user_xattrs () {
     fi
 }
 
+# https://brokenpi.pe/tools/strace-fault-injection
+_have_strace_fault_injection=''
+have_strace_fault_injection() {
+    if test "${_have_strace_fault_injection}" = ''; then
+        if strace -P ${test_srcdir}/libtest-core.sh -e inject=read:retval=0 cat ${test_srcdir}/libtest-core.sh >out.txt &&
+           test '!' -s out.txt; then
+            _have_strace_fault_injection=yes
+        else
+            _have_strace_fault_injection=no
+        fi
+        rm -f out.txt
+    fi
+    test ${_have_strace_fault_injection} = yes
+}
+
+skip_one_without_strace_fault_injection() {
+    if ! have_strace_fault_injection; then
+        echo "ok # SKIP this test requires strace fault injection"
+        return 0
+    fi
+    return 1
+}
+
 skip_without_fuse () {
     fusermount --version >/dev/null 2>&1 || skip "no fusermount"