tests: Fix a possible infinite loop

The POSIX spec for readdir() [1] says:

> If a file is removed from or added to the directory after the most
> recent call to opendir() or rewinddir(), whether a subsequent call
> to readdir() returns an entry for that file is unspecified.

which implies that a loop of readdir()/unlink()/creat() may continue to
return new files unendingly.  This was even observed on a Linux 6.6
tmpfs mount [2].

It's not clear whether find(1) is also permitted to loop endlessly in
this case, but in case it is, let's avoid the whole problem by limiting
the -exec to happen at most once.

[1]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/readdir.html
[2]: https://lore.kernel.org/linux-fsdevel/20231113180616.2831430-1-tavianator@tavianator.com/

1 files changed, 4 insertions, 2 deletions

diff --git a/tests/gnu/ignore_readdir_race_notdir.sh b/tests/gnu/ignore_readdir_race_notdir.sh
index 8b03164..12e9fe6 100644
--- a/tests/gnu/ignore_readdir_race_notdir.sh
+++ b/tests/gnu/ignore_readdir_race_notdir.sh
@@ -1,5 +1,7 @@
 # Check -ignore_readdir_race handling when a directory is replaced with a file
 cd "$TEST"
-"$XTOUCH" -p foo/bar
+mkdir foo
 
-invoke_bfs . -mindepth 1 -ignore_readdir_race -execdir rm -r {} \; -execdir "$XTOUCH" {} \;
+invoke_bfs . -mindepth 1 -ignore_readdir_race \
+    -type d -execdir rmdir {} \; \
+    -execdir "$XTOUCH" {} \;