Merge patch series "filesystems selftests cleanups and fanotify test"

Amir Goldstein <amir73il@gmail.com> says:

This adds a test for fanotify mount ns notifications inside userns [1].

While working on the test I ended up making lots of cleanups to reduce
build dependency on make headers_install.

These patches got rid of the dependency for my kvm setup for the
affected filesystems tests.

Building with TOOLS_INCLUDES dir was recommended by John Hubbard [2].

NOTE #1: these patches are based on a merge of vfs-6.16.mount
(changes wrappers.h) into v6.15-rc5 (changes mount-notify_test.c),
so if this cleanup is acceptable, we should probably setup a selftests
branch for 6.16, so that it can be used to test the fanotify patches.

NOTE #2: some of the defines in wrappers.h are left for overlayfs and
mount_setattr tests, which were not converted to use TOOLS_INCLUDES.
I did not want to mess with those tests.

* patches from https://lore.kernel.org/20250509133240.529330-1-amir73il@gmail.com:
  selftests/fs/mount-notify: add a test variant running inside userns
  selftests/filesystems: create setup_userns() helper
  selftests/filesystems: create get_unique_mnt_id() helper
  selftests/fs/mount-notify: build with tools include dir
  selftests/mount_settattr: remove duplicate syscall definitions
  selftests/pidfd: move syscall definitions into wrappers.h
  selftests/fs/statmount: build with tools include dir
  selftests/filesystems: move wrapper.h out of overlayfs subdir

Link: https://lore.kernel.org/20250509133240.529330-1-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 5 insertions, 81 deletions

diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
index 70cb0c8b21cf0..605a3fa16bf77 100644
--- a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
+++ b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
@@ -14,6 +14,7 @@
 #include <linux/stat.h>
 
 #include "statmount.h"
+#include "../utils.h"
 #include "../../kselftest.h"
 
 #define NSID_PASS 0
@@ -78,87 +79,10 @@ static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
 	return NSID_PASS;
 }
 
-static int get_mnt_id(const char *path, uint64_t *mnt_id)
-{
-	struct statx sx;
-	int ret;
-
-	ret = statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx);
-	if (ret == -1) {
-		ksft_print_msg("retrieving unique mount ID for %s: %s\n", path,
-			       strerror(errno));
-		return NSID_ERROR;
-	}
-
-	if (!(sx.stx_mask & STATX_MNT_ID_UNIQUE)) {
-		ksft_print_msg("no unique mount ID available for %s\n", path);
-		return NSID_ERROR;
-	}
-
-	*mnt_id = sx.stx_mnt_id;
-	return NSID_PASS;
-}
-
-static int write_file(const char *path, const char *val)
-{
-	int fd = open(path, O_WRONLY);
-	size_t len = strlen(val);
-	int ret;
-
-	if (fd == -1) {
-		ksft_print_msg("opening %s for write: %s\n", path, strerror(errno));
-		return NSID_ERROR;
-	}
-
-	ret = write(fd, val, len);
-	if (ret == -1) {
-		ksft_print_msg("writing to %s: %s\n", path, strerror(errno));
-		return NSID_ERROR;
-	}
-	if (ret != len) {
-		ksft_print_msg("short write to %s\n", path);
-		return NSID_ERROR;
-	}
-
-	ret = close(fd);
-	if (ret == -1) {
-		ksft_print_msg("closing %s\n", path);
-		return NSID_ERROR;
-	}
-
-	return NSID_PASS;
-}
-
 static int setup_namespace(void)
 {
-	int ret;
-	char buf[32];
-	uid_t uid = getuid();
-	gid_t gid = getgid();
-
-	ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);
-	if (ret == -1)
-		ksft_exit_fail_msg("unsharing mountns and userns: %s\n",
-				   strerror(errno));
-
-	sprintf(buf, "0 %d 1", uid);
-	ret = write_file("/proc/self/uid_map", buf);
-	if (ret != NSID_PASS)
-		return ret;
-	ret = write_file("/proc/self/setgroups", "deny");
-	if (ret != NSID_PASS)
-		return ret;
-	sprintf(buf, "0 %d 1", gid);
-	ret = write_file("/proc/self/gid_map", buf);
-	if (ret != NSID_PASS)
-		return ret;
-
-	ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
-	if (ret == -1) {
-		ksft_print_msg("making mount tree private: %s\n",
-			       strerror(errno));
+	if (setup_userns() != 0)
 		return NSID_ERROR;
-	}
 
 	return NSID_PASS;
 }
@@ -174,9 +98,9 @@ static int _test_statmount_mnt_ns_id(void)
 	if (ret != NSID_PASS)
 		return ret;
 
-	ret = get_mnt_id("/", &root_id);
-	if (ret != NSID_PASS)
-		return ret;
+	root_id = get_unique_mnt_id("/");
+	if (!root_id)
+		return NSID_ERROR;
 
 	ret = statmount(root_id, 0, STATMOUNT_MNT_NS_ID, &sm, sizeof(sm), 0);
 	if (ret == -1) {