[LTP] [PATCH v9] fsconfig04: Check FSCONFIG_SET_PATH

[Andrea Cervesato]

Hi Wei,

> The fsconfig01.c does not test if FSCONFIG_SET_PATH has any effect;
> most of the calls there just set a dummy "sync" parameter. This test
> case aims to verify if the FSCONFIG_SET_PATH operation can be used
> to dynamically change the external journal device of an ext3 or ext4
> filesystem.
> 
> Closes: https://github.com/linux-test-project/ltp/issues/1169
> Signed-off-by: Wei Gao <wegao@suse.com>
> ---
> v8->v9:
> - Drop braces for single-statement inner branches
> 
>  runtest/syscalls                              |   1 +
>  testcases/kernel/syscalls/fsconfig/.gitignore |   1 +
>  .../kernel/syscalls/fsconfig/fsconfig04.c     | 180 ++++++++++++++++++
>  3 files changed, 182 insertions(+)
>  create mode 100644 testcases/kernel/syscalls/fsconfig/fsconfig04.c
> 
> diff --git a/runtest/syscalls b/runtest/syscalls
> index a021c79da..a7a9cf638 100644
> --- a/runtest/syscalls
> +++ b/runtest/syscalls
> @@ -422,6 +422,7 @@ fremovexattr02 fremovexattr02
>  fsconfig01 fsconfig01
>  fsconfig02 fsconfig02
>  fsconfig03 fsconfig03
> +fsconfig04 fsconfig04
>  
>  fsmount01 fsmount01
>  fsmount02 fsmount02
> diff --git a/testcases/kernel/syscalls/fsconfig/.gitignore b/testcases/kernel/syscalls/fsconfig/.gitignore
> index cfedae5f7..bd3754c34 100644
> --- a/testcases/kernel/syscalls/fsconfig/.gitignore
> +++ b/testcases/kernel/syscalls/fsconfig/.gitignore
> @@ -1,3 +1,4 @@
>  /fsconfig01
>  /fsconfig02
>  /fsconfig03
> +/fsconfig04
> diff --git a/testcases/kernel/syscalls/fsconfig/fsconfig04.c b/testcases/kernel/syscalls/fsconfig/fsconfig04.c
> new file mode 100644
> index 000000000..ce6c8fd01
> --- /dev/null
> +++ b/testcases/kernel/syscalls/fsconfig/fsconfig04.c
> @@ -0,0 +1,180 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2026 Wei Gao <wegao@suse.com>
> + */
> +
> +/*\
> + * This test aims to validate :manpage:`fsconfig(2)` with the
> + * FSCONFIG_SET_PATH operation in dynamically altering the external
> + * journal device of an ext3 or ext4 filesystem. Case acquires three
> + * loop devices (dev0, dev1, dev2), it formats dev1 and dev2 as
> + * external journal devices using the -O journal_dev option and assigns
> + * them the same UUID. Then formats dev0 (the main filesystem) multiple
> + * times, first associating it with dev1, then change to dev2, finally
> + * back to dev1 again as an external journal using the -J device= option.

This is not a description but the Description + Algorithm section. Please
split them so we understand what the test aims for + algorithm that is used.

> + *
> + * 2 Implementation notes in this case need mention:
> + *
> + * - To avoid "journal UUID does not match" error when switch external journal device
> + *   we have to assign same UUID to dev1/dev2
> + * - Before fsconfig test we have to format dev0 associating to dev1->dev2->dev1,
> + *   this will make sure both dev1/2's super block contain correct content. Otherwise
> + *   you will encounter error such as "EXT4-fs (loop0): External journal has more than
> + *   one user (unsupported) - 0" when switch external journal device using fsconfig.
> + */
> +
> +#include "tst_test.h"
> +#include "tst_safe_stdio.h"
> +#include "lapi/fsmount.h"
> +
> +#define MNTPOINT	"mntpoint"
> +#define LOOP_DEV_SIZE 10
> +#define UUID "d73c9e5e-97e4-4a9c-b17e-75a931b02660"
> +
> +static int fd = -1;
> +static char dev0[PATH_MAX];
> +static char dev1[PATH_MAX];
> +static char dev2[PATH_MAX];
> +
> +static void cleanup(void)
> +{
> +	if (fd != -1)
> +		SAFE_CLOSE(fd);
> +
> +	if (dev1[0])
> +		tst_detach_device(dev1);
> +
> +	if (dev2[0])
> +		tst_detach_device(dev2);
> +}
> +
> +static void setup(void)
> +{
> +	fsopen_supported_by_kernel();
> +
> +	strcpy(dev0, tst_device->dev);
> +
> +	if (tst_prealloc_file("dev1_file", 1024 * 1024, LOOP_DEV_SIZE))
> +		tst_brk(TBROK, "Failed to create dev1_file");
> +
> +	if (tst_find_free_loopdev(dev1, sizeof(dev1)) == -1)
> +		tst_brk(TBROK, "No free loop device found for dev1");
> +
> +	if (tst_attach_device(dev1, "dev1_file"))
> +		tst_brk(TBROK, "Failed to attach dev1_file to %s", dev1);
> +
> +	if (tst_prealloc_file("dev2_file", 1024 * 1024, LOOP_DEV_SIZE))
> +		tst_brk(TBROK, "Failed to create dev2_file");
> +
> +	if (tst_find_free_loopdev(dev2, sizeof(dev2)) == -1)
> +		tst_brk(TBROK, "No free loop device found for dev2");
> +
> +	if (tst_attach_device(dev2, "dev2_file"))
> +		tst_brk(TBROK, "Failed to attach dev2_file to %s", dev2);

This code is duplicated. We should create a helper that prealloc
and attach the device.

> +
> +	const char *const *mkfs_opts_set_UUID;
> +	const char *const *mkfs_opts_set_journal_dev1;
> +	const char *const *mkfs_opts_set_journal_dev2;
> +
> +	mkfs_opts_set_UUID = (const char *const []) {"-F", "-U", UUID,
> +		"-O", "journal_dev", NULL};
> +
> +	char device_option_dev1[PATH_MAX];
> +	char device_option_dev2[PATH_MAX];
> +
> +	snprintf(device_option_dev1, sizeof(device_option_dev1), "device=%s", dev1);
> +	snprintf(device_option_dev2, sizeof(device_option_dev2), "device=%s", dev2);
> +
> +	mkfs_opts_set_journal_dev1 = (const char *const []) {"-F", "-J",
> +		device_option_dev1, NULL};
> +
> +	mkfs_opts_set_journal_dev2 = (const char *const []) {"-F", "-J",
> +		device_option_dev2, NULL};
> +
> +	SAFE_MKFS(dev1, tst_device->fs_type, mkfs_opts_set_UUID, NULL);
> +	SAFE_MKFS(dev2, tst_device->fs_type, mkfs_opts_set_UUID, NULL);
> +	SAFE_MKFS(dev0, tst_device->fs_type, mkfs_opts_set_journal_dev1, NULL);
> +	SAFE_MKFS(dev0, tst_device->fs_type, mkfs_opts_set_journal_dev2, NULL);
> +	SAFE_MKFS(dev0, tst_device->fs_type, mkfs_opts_set_journal_dev1, NULL);
> +}
> +
> +static void run(void)
> +{
> +	TEST(fd = fsopen(tst_device->fs_type, 0));
> +	if (fd == -1)
> +		tst_brk(TBROK | TTERRNO, "fsopen() failed");
> +
> +	TEST(fsconfig(fd, FSCONFIG_SET_STRING, "source", dev0, 0));
> +	if (TST_RET == -1)
> +		tst_brk(TBROK | TTERRNO, "fsconfig(FSCONFIG_SET_STRING) failed");
> +
> +	TEST(fsconfig(fd, FSCONFIG_SET_PATH, "journal_path", dev2, 0));
> +	if (TST_RET == -1) {
> +		if (TST_ERR == EOPNOTSUPP)
> +			tst_res(TCONF, "fsconfig(FSCONFIG_SET_PATH) not supported");
> +		else
> +			tst_res(TFAIL | TTERRNO, "fsconfig(FSCONFIG_SET_PATH) failed");
> +		SAFE_CLOSE(fd);
> +		return;
> +	}
> +
> +	TEST(fsconfig(fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0));
> +	if (TST_RET == -1) {
> +		tst_res(TFAIL | TTERRNO, "fsconfig(FSCONFIG_CMD_CREATE) failed");
> +		SAFE_CLOSE(fd);
> +		return;
> +	}
> +
> +	char loop_name[NAME_MAX];
> +	char path[PATH_MAX];
> +	char device_str[NAME_MAX];
> +	unsigned int major, minor, device_num;
> +	unsigned int found = 0;
> +
> +	SAFE_SSCANF(dev2, "/dev/%s", loop_name);
> +
> +	snprintf(path, sizeof(path), "/sys/block/%s/dev", loop_name);
> +	SAFE_FILE_SCANF(path, "%u:%u", &major, &minor);
> +	device_num = (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
> +	snprintf(device_str, sizeof(device_str), "0x%04x", device_num);
> +
> +	char line[PATH_MAX];
> +	FILE *tune2fs;
> +
> +	snprintf(path, sizeof(path), "tune2fs -l %s 2>&1", dev0);
> +	tune2fs = SAFE_POPEN(path, "r");
> +
> +	while (fgets(line, PATH_MAX, tune2fs)) {
> +		if (*line && strstr(line, "Journal device:") && strstr(line, device_str)) {
> +			found = 1;
> +			break;
> +		}
> +	}
> +
> +	if (found == 1)
> +		tst_res(TPASS, "Device found in journal");
> +	else
> +		tst_res(TFAIL, "Device not found in journal");
> +
> +	pclose(tune2fs);
> +	SAFE_CLOSE(fd);
> +}
> +
> +static struct tst_test test = {
> +	.test_all = run,
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.needs_root = 1,
> +	.needs_tmpdir = 1,
> +	.format_device = 1,

we already format the device manually.

> +	.mntpoint = MNTPOINT,
> +	.needs_cmds = (struct tst_cmd []) {
> +		{.cmd = "tune2fs"},
> +		{}
> +	},
> +	.filesystems = (struct tst_fs []) {
> +		{.type = "ext3"},
> +		{.type = "ext4"},
> +		{}
> +	},
> +};
> -- 
> 2.54.0
> 

--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com