It seems that 9pfs does not allow truncating unlinked files, Mark Brown
has noted that NFS may also behave this way.
It doesn't seem quite right to call this a "bug" but it's probably a
special enough case that it makes sense for the test to just SKIP if it
happens.
Signed-off-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
---
tools/testing/selftests/mm/map_populate.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/tools/testing/selftests/mm/map_populate.c b/tools/testing/selftests/mm/map_populate.c
index 5c8a53869b1bd287b09a250edf628a66c25c2439..cdd88531dd9fe98f2d25edf4878659767c919e8e 100644
--- a/tools/testing/selftests/mm/map_populate.c
+++ b/tools/testing/selftests/mm/map_populate.c
@@ -87,6 +87,13 @@ int main(int argc, char **argv)
BUG_ON(!ftmp, "tmpfile()");
ret = ftruncate(fileno(ftmp), MMAP_SZ);
+ if (ret < 0 && errno == ENOENT) {
+ /*
+ * This probably means tmpfile() made a file on a filesystem
+ * that doesn't handle temporary files the way we want.
+ */
+ ksft_exit_skip("ftruncate(fileno(tmpfile())) gave ENOENT, weird filesystem?");
+ }
BUG_ON(ret, "ftruncate()");
smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE,
--
2.48.1.601.g30ceb7b040-goog
