[PATCH fstests] generic/755: test that inode's ctime is updated on unlink

[Jeff Layton <jlayton@kernel.org>]

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
HCH suggested I roll a fstest for this problem that I found in btrfs the
other day. In principle, we probably could expand this to other dir
operations and to check the parent timestamps, but having to do all that
in C is a pain.  I didn't see a good way to use xfs_io for this,
however.
---
 src/Makefile          |  2 +-
 src/unlink-ctime.c    | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/generic/755     | 26 ++++++++++++++++++++++++++
 tests/generic/755.out |  2 ++
 4 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/src/Makefile b/src/Makefile
index 9979613711c9..c71fa41e4668 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -34,7 +34,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	attr_replace_test swapon mkswap t_attr_corruption t_open_tmpfiles \
 	fscrypt-crypt-util bulkstat_null_ocount splice-test chprojid_fail \
 	detached_mounts_propagation ext4_resize t_readdir_3 splice2pipe \
-	uuid_ioctl t_snapshot_deleted_subvolume fiemap-fault
+	uuid_ioctl t_snapshot_deleted_subvolume fiemap-fault unlink-ctime
 
 EXTRA_EXECS = dmerror fill2attr fill2fs fill2fs_check scaleread.sh \
 	      btrfs_crc32c_forged_name.py popdir.pl popattr.py \
diff --git a/src/unlink-ctime.c b/src/unlink-ctime.c
new file mode 100644
index 000000000000..7661e340eaba
--- /dev/null
+++ b/src/unlink-ctime.c
@@ -0,0 +1,50 @@
+#define _GNU_SOURCE 1
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+int main(int argc, char **argv)
+{
+	int fd, ret;
+	struct statx before, after;
+
+	if (argc < 2) {
+		fprintf(stderr, "Must specify filename!\n");
+		return 1;
+	}
+
+	fd = open(argv[1], O_RDWR|O_CREAT, 0600);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	ret = statx(fd, "", AT_EMPTY_PATH, STATX_CTIME, &before);
+	if (ret) {
+		perror("statx");
+		return 1;
+	}
+
+	sleep(1);
+
+	ret = unlink(argv[1]);
+	if (ret) {
+		perror("unlink");
+		return 1;
+	}
+
+	ret = statx(fd, "", AT_EMPTY_PATH, STATX_CTIME, &after);
+	if (ret) {
+		perror("statx");
+		return 1;
+	}
+
+	if (before.stx_ctime.tv_nsec == after.stx_ctime.tv_nsec &&
+	    before.stx_ctime.tv_sec == after.stx_ctime.tv_sec) {
+		printf("No change to ctime after unlink!\n");
+		return 1;
+	}
+	return 0;
+}
diff --git a/tests/generic/755 b/tests/generic/755
new file mode 100755
index 000000000000..500c51f99630
--- /dev/null
+++ b/tests/generic/755
@@ -0,0 +1,26 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2024, Jeff Layton <jlayton@kernel.org>
+#
+# FS QA Test No. 755
+#
+# Create a file, stat it and then unlink it. Does the ctime of the
+# target inode change?
+#
+. ./common/preamble
+_begin_fstest auto quick
+
+# Import common functions.
+. ./common/filter
+. ./common/dmerror
+
+_require_test
+_require_test_program unlink-ctime
+
+testfile="$TEST_DIR/unlink-ctime.$$"
+
+$here/src/unlink-ctime $testfile
+
+echo Silence is golden
+status=0
+exit
diff --git a/tests/generic/755.out b/tests/generic/755.out
new file mode 100644
index 000000000000..7c9ea51cd298
--- /dev/null
+++ b/tests/generic/755.out
@@ -0,0 +1,2 @@
+QA output created by 755
+Silence is golden

---
base-commit: f5ada754d5838d29fd270257003d0d123a9d1cd2
change-id: 20240813-master-e3b46de630bd

Best regards,
-- 
Jeff Layton <jlayton@kernel.org>