Re: [LTP] [PATCH v1] fsconfig04.c: Check FSCONFIG_SET_PATH

Petr Vorel
2025-05-22T20:57:06Z

Hi Wei,

I'm sorry not a real review, just point out obvious API errors.

> Fixes: 1169
Fixes: #1169

> The fsconfig01.c does not test if FSCONFIG_SET_PATH have any effect,
> most of the calls there just set 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 ext3 or ext4
> filesystem.

...
> diff --git a/testcases/kernel/syscalls/fsconfig/fsconfig04.c b/testcases/kernel/syscalls/fsconfig/fsconfig04.c
> new file mode 100644
> index 000000000..119b8b175
> --- /dev/null
> +++ b/testcases/kernel/syscalls/fsconfig/fsconfig04.c
> @@ -0,0 +1,169 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2025 Wei Gao <wegao@suse.com>
> + *
This '*' should be '/*\' to be docparse.

> + * This test aims to validate the functionality of fsconfig(FSCONFIG_SET_PATH) in
> + * dynamically altering the external journal device of a 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.
> + *
> + * 2 workarounds in this case need mention:
And here should be new line, right?

> + * - 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 formats dev0 associating to dev1->dev2->dev1,
> + * this will make sure both dev1/2's supper 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 "lapi/fsmount.h"

> +#include "old/old_device.h"
Why this?

> +
> +#define MNTPOINT "mntpoint"
> +#define LOOP_DEV_SIZE 10
> +#define UUID "d73c9e5e-97e4-4a9c-b17e-75a931b02660"
> +
> +static int fd;
> +static const char *dev;
> +static char dev0[NAME_MAX];
> +static char dev1[NAME_MAX];
> +static char dev2[NAME_MAX];
> +
> +static void cleanup(void)
> +{
> + if (fd != -1)
> + SAFE_CLOSE(fd);
> +
> + TST_EXP_PASS_SILENT(tst_detach_device(dev1));
> + TST_EXP_PASS_SILENT(tst_detach_device(dev2));
> +}
> +
> +static void setup(void)
> +{
> + int ret = tst_system("tune2fs");
> +
> + if (WEXITSTATUS(ret) == 127)
> + tst_brk(TCONF, "tune2fs does not exist");

We have .needs_cmds

> +
> + strcpy(dev0, tst_device->dev);
> + dev = tst_acquire_loop_device(LOOP_DEV_SIZE, "dev1_file");
> + if (!dev)
> + tst_brk(TBROK, "acquire loop dev1 failed");
> +
> + strcpy(dev1, dev);
> + dev = NULL;
> +
> + dev = tst_acquire_loop_device(LOOP_DEV_SIZE, "dev2_file");
> + if (!dev)
> + tst_brk(TBROK, "acquire loop dev2 failed");
> + strcpy(dev2, dev);
> +
> + 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};
very nit: why the args cannot be on a single line?

> +
> + char device_option_dev1[PATH_MAX];
> + char device_option_dev2[PATH_MAX];
> +
> + sprintf(device_option_dev1, "device=%s", dev1);
> + sprintf(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(TFAIL | 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_brk(TCONF, "fsconfig(FSCONFIG_SET_PATH) not supported");
> + else
> + tst_brk(TFAIL | TTERRNO, "fsconfig(FSCONFIG_SET_PATH) failed");
> + }
> +
> + TEST(fsconfig(fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0));
> + if (TST_RET == -1)
> + tst_brk(TFAIL | TTERRNO, "fsconfig(FSCONFIG_CMD_CREATE) failed");
> +
> + char loop_name[NAME_MAX];
> + char path[PATH_MAX];
> + char device_str[NAME_MAX];
> + unsigned int major, minor, device_num;
> + unsigned int found = 0;
> +
> + int ret = sscanf(dev2, "/dev/%s", loop_name);
> +
> + if (ret != 1)
> + tst_brk(TFAIL | TTERRNO, "can not parse loop_name");
> +
> + sprintf(path, "/sys/block/%s/dev", loop_name);
> + SAFE_FILE_SCANF(path, "%u:%u", &major, &minor);
> + device_num = (major << 8) | minor;
> + sprintf(device_str, "0x%04X", device_num);
> +
> + char line[PATH_MAX];
> + FILE *tune2fs;
> +
> + sprintf(path, "tune2fs -l %s 2>&1", dev0);
> + tune2fs = 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, "Journal device set pass");
Maybe "Device found in journal" ?
> + else
> + tst_res(TFAIL, "Journal device set failed");
Maybe "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,
> + .format_device = 1,
> + .mntpoint = MNTPOINT,
> + .all_filesystems = 1,
> + .skip_filesystems = (const char *const []){"ntfs", "vfat", "exfat",
> + "ext2", "tmpfs", "xfs", "btrfs", NULL},
So you skip nearly everything, right?
Why not use .mount_device = 1 ? That would mount the default filesystem.

Kind regards,
Petr

> +};