[PATCH for-9.0 2/3] qtest/virtio-9p-test.c: consolidate hardlink tests

[Daniel Henrique Barboza <dbarboza@ventanamicro.com>]

We need all virtio-9p-test.c tests to clean themselves up after being
executed to avoid an issue where multiple test runs of this same test
will find remains of the previous run. See [1] to see the side effects
of that.

Previous patch dealt with most tests in this file. We're now
consolidating the 'hardlink' tests:

- copy the asserts that checks if the created link is a hard link from
  fs_hardlink_file() to fs_unlinkat_hardlink(). This will make
  fs_unlinkat_hardlink() do exactly what fs_hardlink_file() is doing;

- remove fs_hardlink_file();

- fs_unlinkat_hardlink() is renamed to fs_create_unlinkat_hardlink().
  We'll also remove 'real_file' and the '08' dir it creates.

With this last change all local 9p tests of the file are not leaving
files or dirs behind in the temporary dir, allowing multiple runs in the
same session to succeed.

[1] https://mail.gnu.org/archive/html/qemu-devel/2024-03/msg05807.html

Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
---
 tests/qtest/virtio-9p-test.c | 55 +++++++++++++++---------------------
 1 file changed, 22 insertions(+), 33 deletions(-)

diff --git a/tests/qtest/virtio-9p-test.c b/tests/qtest/virtio-9p-test.c
index cdbe3e78ea..9938516fe7 100644
--- a/tests/qtest/virtio-9p-test.c
+++ b/tests/qtest/virtio-9p-test.c
@@ -600,39 +600,13 @@ static void fs_create_unlinkat_symlink(void *obj, void *data,
     g_assert(stat(new_dir, &st) != 0);
 }
 
-static void fs_hardlink_file(void *obj, void *data, QGuestAllocator *t_alloc)
+static void fs_create_unlinkat_hardlink(void *obj, void *data,
+                                        QGuestAllocator *t_alloc)
 {
     QVirtio9P *v9p = obj;
     v9fs_set_allocator(t_alloc);
-    struct stat st_real, st_link;
-    g_autofree char *real_file = virtio_9p_test_path("07/real_file");
-    g_autofree char *hardlink_file = virtio_9p_test_path("07/hardlink_file");
-
-    tattach({ .client = v9p });
-    tmkdir({ .client = v9p, .atPath = "/", .name = "07" });
-    tlcreate({ .client = v9p, .atPath = "07", .name = "real_file" });
-    g_assert(stat(real_file, &st_real) == 0);
-    g_assert((st_real.st_mode & S_IFMT) == S_IFREG);
-
-    tlink({
-        .client = v9p, .atPath = "07", .name = "hardlink_file",
-        .toPath = "07/real_file"
-    });
-
-    /* check if link exists now ... */
-    g_assert(stat(hardlink_file, &st_link) == 0);
-    /* ... and it's a hard link, right? */
-    g_assert((st_link.st_mode & S_IFMT) == S_IFREG);
-    g_assert(st_link.st_dev == st_real.st_dev);
-    g_assert(st_link.st_ino == st_real.st_ino);
-}
-
-static void fs_unlinkat_hardlink(void *obj, void *data,
-                                 QGuestAllocator *t_alloc)
-{
-    QVirtio9P *v9p = obj;
-    v9fs_set_allocator(t_alloc);
-    struct stat st_real, st_link;
+    struct stat st_real, st_link, st;
+    g_autofree char *new_dir = virtio_9p_test_path("08");
     g_autofree char *real_file = virtio_9p_test_path("08/real_file");
     g_autofree char *hardlink_file = virtio_9p_test_path("08/hardlink_file");
 
@@ -646,13 +620,29 @@ static void fs_unlinkat_hardlink(void *obj, void *data,
         .client = v9p, .atPath = "08", .name = "hardlink_file",
         .toPath = "08/real_file"
     });
+
+    /* check if link exists now ... */
     g_assert(stat(hardlink_file, &st_link) == 0);
+    /* ... and it's a hard link, right? */
+    g_assert((st_link.st_mode & S_IFMT) == S_IFREG);
+    g_assert(st_link.st_dev == st_real.st_dev);
+    g_assert(st_link.st_ino == st_real.st_ino);
 
     tunlinkat({ .client = v9p, .atPath = "08", .name = "hardlink_file" });
     /* symlink should be gone now */
     g_assert(stat(hardlink_file, &st_link) != 0);
     /* and old file should still exist */
     g_assert(stat(real_file, &st_real) == 0);
+
+    /* cleanup: remove old file and dir */
+    tunlinkat({ .client = v9p, .atPath = "08", .name = "real_file" });
+    g_assert(stat(real_file, &st_real) != 0);
+
+    tunlinkat({
+        .client = v9p, .atPath = "/", .name = "08",
+        .flags = P9_DOTL_AT_REMOVEDIR
+    });
+    g_assert(stat(new_dir, &st) != 0);
 }
 
 static void *assign_9p_local_driver(GString *cmd_line, void *arg)
@@ -714,9 +704,8 @@ static void register_virtio_9p_test(void)
                  fs_create_unlinkat_file, &opts);
     qos_add_test("local/create_unlinkat_symlink", "virtio-9p",
                  fs_create_unlinkat_symlink, &opts);
-    qos_add_test("local/hardlink_file", "virtio-9p", fs_hardlink_file, &opts);
-    qos_add_test("local/unlinkat_hardlink", "virtio-9p", fs_unlinkat_hardlink,
-                 &opts);
+    qos_add_test("local/create_unlinkat_hardlink", "virtio-9p",
+                 fs_create_unlinkat_hardlink, &opts);
 }
 
 libqos_init(register_virtio_9p_test);
-- 
2.44.0