| Message ID | 20250307204046.322691-1-mszeredi@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | selftests: add tests for mount notification | expand |
On Fri, Mar 07, 2025 at 09:40:45PM +0100, Miklos Szeredi wrote: > Provide coverage for all mnt_notify_add() instances. > > Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> > --- Thank you! Tests are most excellent! > tools/testing/selftests/Makefile | 1 + > .../filesystems/mount-notify/.gitignore | 2 + > .../filesystems/mount-notify/Makefile | 6 + > .../mount-notify/mount-notify_test.c | 586 ++++++++++++++++++ > .../filesystems/statmount/statmount.h | 2 +- > 5 files changed, 596 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/filesystems/mount-notify/.gitignore > create mode 100644 tools/testing/selftests/filesystems/mount-notify/Makefile > create mode 100644 tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c > > diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile > index 8daac70c2f9d..2ebaf5e6942e 100644 > --- a/tools/testing/selftests/Makefile > +++ b/tools/testing/selftests/Makefile > @@ -35,6 +35,7 @@ TARGETS += filesystems/epoll > TARGETS += filesystems/fat > TARGETS += filesystems/overlayfs > TARGETS += filesystems/statmount > +TARGETS += filesystems/mount-notify > TARGETS += firmware > TARGETS += fpu > TARGETS += ftrace > diff --git a/tools/testing/selftests/filesystems/mount-notify/.gitignore b/tools/testing/selftests/filesystems/mount-notify/.gitignore > new file mode 100644 > index 000000000000..82a4846cbc4b > --- /dev/null > +++ b/tools/testing/selftests/filesystems/mount-notify/.gitignore > @@ -0,0 +1,2 @@ > +# SPDX-License-Identifier: GPL-2.0-only > +/*_test > diff --git a/tools/testing/selftests/filesystems/mount-notify/Makefile b/tools/testing/selftests/filesystems/mount-notify/Makefile > new file mode 100644 > index 000000000000..10be0227b5ae > --- /dev/null > +++ b/tools/testing/selftests/filesystems/mount-notify/Makefile > @@ -0,0 +1,6 @@ > +# SPDX-License-Identifier: GPL-2.0-or-later > + > +CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) > +TEST_GEN_PROGS := mount-notify_test > + > +include ../../lib.mk > diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c > new file mode 100644 > index 000000000000..d39ff57bf163 > --- /dev/null > +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c > @@ -0,0 +1,586 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +// Copyright (c) 2025 Miklos Szeredi <miklos@szeredi.hu> > + > +#define _GNU_SOURCE > +#include <fcntl.h> > +#include <sched.h> > +#include <stdio.h> > +#include <string.h> > +#include <sys/stat.h> > +#include <sys/mount.h> > +#include <linux/fanotify.h> > +#include <unistd.h> > +#include <sys/fanotify.h> > +#include <sys/syscall.h> > + > +#include "../../kselftest_harness.h" > +#include "../statmount/statmount.h" > + > +static char root_mntpoint[] = "/tmp/mount-notify_test_root.XXXXXX"; > +static int orig_root, ns_fd; > +static uint64_t root_id; > + > +static uint64_t get_mnt_id(const char *path) > +{ > + struct statx sx; > + int ret; > + > + ret = statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx); > + if (ret == -1) > + ksft_exit_fail_perror("retrieving mount ID"); > + > + if (!(sx.stx_mask & STATX_MNT_ID_UNIQUE)) > + ksft_exit_fail_msg("no mount ID available\n"); > + > + return sx.stx_mnt_id; > +} > + > +static void cleanup_namespace(void) > +{ > + int ret; > + > + ret = fchdir(orig_root); > + if (ret == -1) > + ksft_perror("fchdir to original root"); > + > + ret = chroot("."); > + if (ret == -1) > + ksft_perror("chroot to original root"); > + > + umount2(root_mntpoint, MNT_DETACH); > + chdir(root_mntpoint); > + rmdir("a"); > + rmdir("b"); > + chdir("/"); > + rmdir(root_mntpoint); > +} > + > +static void setup_namespace(void) > +{ > + int ret; > + > + ret = unshare(CLONE_NEWNS); > + if (ret == -1) > + ksft_exit_fail_perror("unsharing mountns and userns"); > + > + ns_fd = open("/proc/self/ns/mnt", O_RDONLY); > + if (ns_fd == -1) > + ksft_exit_fail_perror("opening /proc/self/ns/mnt"); > + > + ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL); > + if (ret == -1) > + ksft_exit_fail_perror("making mount tree private"); > + > + if (!mkdtemp(root_mntpoint)) > + ksft_exit_fail_perror("creating temporary directory"); > + > + orig_root = open("/", O_PATH); > + if (orig_root == -1) > + ksft_exit_fail_perror("opening root directory"); > + > + atexit(cleanup_namespace); > + > + ret = mount(root_mntpoint, root_mntpoint, NULL, MS_BIND, NULL); > + if (ret == -1) > + ksft_exit_fail_perror("mounting temp root"); > + > + ret = chroot(root_mntpoint); > + if (ret == -1) > + ksft_exit_fail_perror("chroot to temp root"); > + > + ret = chdir("/"); > + if (ret == -1) > + ksft_exit_fail_perror("chdir to root"); > + > + ret = mkdir("a", 0700); > + if (ret == -1) > + ksft_exit_fail_perror("mkdir(a)"); > + > + ret = mkdir("b", 0700); > + if (ret == -1) > + ksft_exit_fail_perror("mkdir(b)"); > + > + root_id = get_mnt_id("/"); > +} > + > +FIXTURE(fanotify) { > + int fan_fd; > + char buf[256]; > + unsigned int rem; > + void *next; > +}; > + > +#define MAX_MNTS 256 > +#define MAX_PATH 256 > + > +FIXTURE_SETUP(fanotify) > +{ > + uint64_t list[MAX_MNTS]; > + ssize_t num; > + size_t bufsize = sizeof(struct statmount) + MAX_PATH; > + struct statmount *buf = alloca(bufsize); > + unsigned int i; > + int ret; > + > + // Clean up mount tree > + ret = mount("", "/", NULL, MS_PRIVATE, NULL); > + ASSERT_EQ(ret, 0); > + > + num = listmount(LSMT_ROOT, 0, 0, list, MAX_MNTS, 0); > + ASSERT_GE(num, 1); > + ASSERT_LT(num, MAX_MNTS); > + > + for (i = 0; i < num; i++) { > + if (list[i] == root_id) > + continue; > + ret = statmount(list[i], 0, STATMOUNT_MNT_POINT, buf, bufsize, 0); > + if (ret == 0 && buf->mask & STATMOUNT_MNT_POINT) > + umount2(buf->str + buf->mnt_point, MNT_DETACH); > + } > + num = listmount(LSMT_ROOT, 0, 0, list, 2, 0); > + ASSERT_EQ(num, 1); > + ASSERT_EQ(list[0], root_id); > + > + mkdir("/a", 0700); > + mkdir("/b", 0700); > + > + self->fan_fd = fanotify_init(FAN_REPORT_MNT, 0); > + ASSERT_GE(self->fan_fd, 0); > + > + ret = fanotify_mark(self->fan_fd, FAN_MARK_ADD | FAN_MARK_MNTNS, > + FAN_MNT_ATTACH | FAN_MNT_DETACH, ns_fd, NULL); > + ASSERT_EQ(ret, 0); > + > + self->rem = 0; > +} > + > +FIXTURE_TEARDOWN(fanotify) > +{ > + ASSERT_EQ(self->rem, 0); > + close(self->fan_fd); > +} > + > +static uint64_t expect_notify(struct __test_metadata *const _metadata, > + FIXTURE_DATA(fanotify) *self, > + uint64_t *mask) > +{ > + struct fanotify_event_metadata *meta; > + struct fanotify_event_info_mnt *mnt; > + unsigned int thislen; > + > + if (!self->rem) { > + ssize_t len = read(self->fan_fd, self->buf, sizeof(self->buf)); > + ASSERT_GT(len, 0); > + > + self->rem = len; > + self->next = (void *) self->buf; > + } > + > + meta = self->next; > + ASSERT_TRUE(FAN_EVENT_OK(meta, self->rem)); > + > + thislen = meta->event_len; > + self->rem -= thislen; > + self->next += thislen; > + > + *mask = meta->mask; > + thislen -= sizeof(*meta); > + > + mnt = ((void *) meta) + meta->event_len - thislen; > + > + ASSERT_EQ(thislen, sizeof(*mnt)); > + > + return mnt->mnt_id; > +} > + > +static void expect_notify_n(struct __test_metadata *const _metadata, > + FIXTURE_DATA(fanotify) *self, > + unsigned int n, uint64_t mask[], uint64_t mnts[]) > +{ > + unsigned int i; > + > + for (i = 0; i < n; i++) > + mnts[i] = expect_notify(_metadata, self, &mask[i]); > +} > + > +static uint64_t expect_notify_mask(struct __test_metadata *const _metadata, > + FIXTURE_DATA(fanotify) *self, > + uint64_t expect_mask) > +{ > + uint64_t mntid, mask; > + > + mntid = expect_notify(_metadata, self, &mask); > + ASSERT_EQ(expect_mask, mask); > + > + return mntid; > +} > + > + > +static void expect_notify_mask_n(struct __test_metadata *const _metadata, > + FIXTURE_DATA(fanotify) *self, > + uint64_t mask, unsigned int n, uint64_t mnts[]) > +{ > + unsigned int i; > + > + for (i = 0; i < n; i++) > + mnts[i] = expect_notify_mask(_metadata, self, mask); > +} > + > + > +static void verify_mount_ids(struct __test_metadata *const _metadata, > + const uint64_t list1[], const uint64_t list2[], > + size_t num) > +{ > + unsigned int i, j; > + > + // Check that neither list has any duplicates > + for (i = 0; i < num; i++) { > + for (j = 0; j < num; j++) { > + if (i != j) { > + ASSERT_NE(list1[i], list1[j]); > + ASSERT_NE(list2[i], list2[j]); > + } > + } > + } > + // Check that all list1 memebers can be found in list2. Together with > + // the above it means that the list1 and list2 represent the same sets. > + for (i = 0; i < num; i++) { > + for (j = 0; j < num; j++) { > + if (list1[i] == list2[j]) > + break; > + } > + ASSERT_NE(j, num); > + } > +} > + > +static void check_mounted(struct __test_metadata *const _metadata, > + const uint64_t mnts[], size_t num) > +{ > + ssize_t ret; > + uint64_t *list; > + > + list = malloc((num + 1) * sizeof(list[0])); > + ASSERT_NE(list, NULL); > + > + ret = listmount(LSMT_ROOT, 0, 0, list, num + 1, 0); > + ASSERT_EQ(ret, num); > + > + verify_mount_ids(_metadata, mnts, list, num); > + > + free(list); > +} > + > +static void setup_mount_tree(struct __test_metadata *const _metadata, > + int log2_num) > +{ > + int ret, i; > + > + ret = mount("", "/", NULL, MS_SHARED, NULL); > + ASSERT_EQ(ret, 0); > + > + for (i = 0; i < log2_num; i++) { > + ret = mount("/", "/", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + } > +} > + > +TEST_F(fanotify, bind) > +{ > + int ret; > + uint64_t mnts[2] = { root_id }; > + > + ret = mount("/", "/", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + > + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); > + ASSERT_NE(mnts[0], mnts[1]); > + > + check_mounted(_metadata, mnts, 2); > + > + // Cleanup > + uint64_t detach_id; > + ret = umount("/"); > + ASSERT_EQ(ret, 0); > + > + detach_id = expect_notify_mask(_metadata, self, FAN_MNT_DETACH); > + ASSERT_EQ(detach_id, mnts[1]); > + > + check_mounted(_metadata, mnts, 1); > +} > + > +TEST_F(fanotify, move) > +{ > + int ret; > + uint64_t mnts[2] = { root_id }; > + uint64_t move_id; > + > + ret = mount("/", "/a", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + > + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); > + ASSERT_NE(mnts[0], mnts[1]); > + > + check_mounted(_metadata, mnts, 2); > + > + ret = move_mount(AT_FDCWD, "/a", AT_FDCWD, "/b", 0); > + ASSERT_EQ(ret, 0); > + > + move_id = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH | FAN_MNT_DETACH); > + ASSERT_EQ(move_id, mnts[1]); > + > + // Cleanup > + ret = umount("/b"); > + ASSERT_EQ(ret, 0); > + > + check_mounted(_metadata, mnts, 1); > +} > + > +TEST_F(fanotify, propagate) > +{ > + const unsigned int log2_num = 4; > + const unsigned int num = (1 << log2_num); > + uint64_t mnts[num]; > + > + setup_mount_tree(_metadata, log2_num); > + > + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, num - 1, mnts + 1); > + > + mnts[0] = root_id; > + check_mounted(_metadata, mnts, num); > + > + // Cleanup > + int ret; > + uint64_t mnts2[num]; > + ret = umount2("/", MNT_DETACH); > + ASSERT_EQ(ret, 0); > + > + ret = mount("", "/", NULL, MS_PRIVATE, NULL); > + ASSERT_EQ(ret, 0); > + > + mnts2[0] = root_id; > + expect_notify_mask_n(_metadata, self, FAN_MNT_DETACH, num - 1, mnts2 + 1); > + verify_mount_ids(_metadata, mnts, mnts2, num); > + > + check_mounted(_metadata, mnts, 1); > +} > + > +TEST_F(fanotify, fsmount) > +{ > + int ret, fs, mnt; > + uint64_t mnts[2] = { root_id }; > + > + fs = fsopen("tmpfs", 0); > + ASSERT_GE(fs, 0); > + > + ret = fsconfig(fs, FSCONFIG_CMD_CREATE, 0, 0, 0); > + ASSERT_EQ(ret, 0); > + > + mnt = fsmount(fs, 0, 0); > + ASSERT_GE(mnt, 0); > + > + close(fs); > + > + ret = move_mount(mnt, "", AT_FDCWD, "/a", MOVE_MOUNT_F_EMPTY_PATH); > + ASSERT_EQ(ret, 0); > + > + close(mnt); > + > + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); > + ASSERT_NE(mnts[0], mnts[1]); > + > + check_mounted(_metadata, mnts, 2); > + > + // Cleanup > + uint64_t detach_id; > + ret = umount("/a"); > + ASSERT_EQ(ret, 0); > + > + detach_id = expect_notify_mask(_metadata, self, FAN_MNT_DETACH); > + ASSERT_EQ(detach_id, mnts[1]); > + > + check_mounted(_metadata, mnts, 1); > +} > + > +TEST_F(fanotify, reparent) > +{ > + uint64_t mnts[6] = { root_id }; > + uint64_t dmnts[3]; > + uint64_t masks[3]; > + unsigned int i; > + int ret; > + > + // Create setup with a[1] -> b[2] propagation > + ret = mount("/", "/a", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + > + ret = mount("", "/a", NULL, MS_SHARED, NULL); > + ASSERT_EQ(ret, 0); > + > + ret = mount("/a", "/b", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + > + ret = mount("", "/b", NULL, MS_SLAVE, NULL); > + ASSERT_EQ(ret, 0); > + > + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, 2, mnts + 1); > + > + check_mounted(_metadata, mnts, 3); > + > + // Mount on a[3], which is propagated to b[4] > + ret = mount("/", "/a", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + > + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, 2, mnts + 3); > + > + check_mounted(_metadata, mnts, 5); > + > + // Mount on b[5], not propagated > + ret = mount("/", "/b", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + > + mnts[5] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); > + > + check_mounted(_metadata, mnts, 6); > + > + // Umount a[3], which is propagated to b[4], but not b[5] > + // This will result in b[5] "falling" on b[2] > + ret = umount("/a"); > + ASSERT_EQ(ret, 0); > + > + expect_notify_n(_metadata, self, 3, masks, dmnts); > + verify_mount_ids(_metadata, mnts + 3, dmnts, 3); > + > + for (i = 0; i < 3; i++) { > + if (dmnts[i] == mnts[5]) { > + ASSERT_EQ(masks[i], FAN_MNT_ATTACH | FAN_MNT_DETACH); > + } else { > + ASSERT_EQ(masks[i], FAN_MNT_DETACH); > + } > + } > + > + mnts[3] = mnts[5]; > + check_mounted(_metadata, mnts, 4); > + > + // Cleanup > + ret = umount("/b"); > + ASSERT_EQ(ret, 0); > + > + ret = umount("/a"); > + ASSERT_EQ(ret, 0); > + > + ret = umount("/b"); > + ASSERT_EQ(ret, 0); > + > + expect_notify_mask_n(_metadata, self, FAN_MNT_DETACH, 3, dmnts); > + verify_mount_ids(_metadata, mnts + 1, dmnts, 3); > + > + check_mounted(_metadata, mnts, 1); > +} > + > +TEST_F(fanotify, rmdir) > +{ > + uint64_t mnts[3] = { root_id }; > + int ret; > + > + ret = mount("/", "/a", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + > + ret = mount("/", "/a/b", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + > + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, 2, mnts + 1); > + > + check_mounted(_metadata, mnts, 3); > + > + ret = chdir("/a"); > + ASSERT_EQ(ret, 0); > + > + ret = fork(); > + ASSERT_GE(ret, 0); > + > + if (ret == 0) { > + chdir("/"); > + unshare(CLONE_NEWNS); > + mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL); > + umount2("/a", MNT_DETACH); > + // This triggers a detach in the other namespace > + rmdir("/a"); > + exit(0); > + } > + wait(NULL); > + > + expect_notify_mask_n(_metadata, self, FAN_MNT_DETACH, 2, mnts + 1); > + check_mounted(_metadata, mnts, 1); > + > + // Cleanup > + ret = chdir("/"); > + ASSERT_EQ(ret, 0); > + > + ret = mkdir("a", 0700); > + ASSERT_EQ(ret, 0); > +} > + > +TEST_F(fanotify, pivot_root) > +{ > + uint64_t mnts[3] = { root_id }; > + uint64_t mnts2[3]; > + int ret; > + > + ret = mount("tmpfs", "/a", "tmpfs", 0, NULL); > + ASSERT_EQ(ret, 0); > + > + mnts[2] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); > + > + ret = mkdir("/a/new", 0700); > + ASSERT_EQ(ret, 0); > + > + ret = mkdir("/a/old", 0700); > + ASSERT_EQ(ret, 0); > + > + ret = mount("/a", "/a/new", NULL, MS_BIND, NULL); > + ASSERT_EQ(ret, 0); > + > + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); > + check_mounted(_metadata, mnts, 3); > + > + ret = syscall(SYS_pivot_root, "/a/new", "/a/new/old"); > + ASSERT_EQ(ret, 0); > + > + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH | FAN_MNT_DETACH, 2, mnts2); > + verify_mount_ids(_metadata, mnts, mnts2, 2); > + check_mounted(_metadata, mnts, 3); > + > + // Cleanup > + ret = syscall(SYS_pivot_root, "/old", "/old/a/new"); > + ASSERT_EQ(ret, 0); > + > + ret = umount("/a/new"); > + ASSERT_EQ(ret, 0); > + > + ret = umount("/a"); > + ASSERT_EQ(ret, 0); > + > + check_mounted(_metadata, mnts, 1); > +} > + > +int main(int argc, char *argv[]) > +{ > + int ret; > + > + ksft_print_header(); > + > + if (geteuid()) > + ksft_exit_skip("mount notify requires root privileges\n"); > + > + ret = fanotify_init(FAN_REPORT_MNT, 0); > + if (ret == -1) { > + if (errno == EINVAL) > + ksft_exit_skip("FAN_REPORT_MNT not supported\n"); > + ksft_exit_fail_perror("fanotify_init(FAN_REPORT_MNT, 0)"); > + } > + close(ret); > + > + setup_namespace(); > + > + return test_harness_run(argc, argv); > +} Thanks for using the TEST_* framework instead of the old one! It's way easier to extend and has better behavior! But you don't need a main function. You can just use: TEST_HARNESS_MAIN setup_namespace() can just be called on each FIXTURE_SETUP() invocation and cleanup_namespace() on each FIXTURE_TEARDOWN(). They will always start with a clean slate this way. There's some build errors with missing defines when the kheaders aren't installed. I don't like making this a test-run prerequisite so I'm adding defines when FAN_MNT_ATTACH etc aren't defined. I've fixed that all up. I'm appending the changes I folded in. Afterwards I get: user1@localhost:~/data/kernel/linux/tools/testing/selftests/filesystems/mount-notify$ sudo ./mount-notify_test TAP version 13 1..7 # Starting 7 tests from 1 test cases. # RUN fanotify.bind ... # OK fanotify.bind ok 1 fanotify.bind # RUN fanotify.move ... # OK fanotify.move ok 2 fanotify.move # RUN fanotify.propagate ... # OK fanotify.propagate ok 3 fanotify.propagate # RUN fanotify.fsmount ... # OK fanotify.fsmount ok 4 fanotify.fsmount # RUN fanotify.reparent ... # OK fanotify.reparent ok 5 fanotify.reparent # RUN fanotify.rmdir ... # OK fanotify.rmdir ok 6 fanotify.rmdir # RUN fanotify.pivot_root ... # OK fanotify.pivot_root ok 7 fanotify.pivot_root # PASSED: 7 / 7 tests passed. # Totals: pass:7 fail:0 xfail:0 xpass:0 skip:0 error:0 > diff --git a/tools/testing/selftests/filesystems/statmount/statmount.h b/tools/testing/selftests/filesystems/statmount/statmount.h > index f4294bab9d73..a7a5289ddae9 100644 > --- a/tools/testing/selftests/filesystems/statmount/statmount.h > +++ b/tools/testing/selftests/filesystems/statmount/statmount.h > @@ -25,7 +25,7 @@ static inline int statmount(uint64_t mnt_id, uint64_t mnt_ns_id, uint64_t mask, > return syscall(__NR_statmount, &req, buf, bufsize, flags); > } > > -static ssize_t listmount(uint64_t mnt_id, uint64_t mnt_ns_id, > +static inline ssize_t listmount(uint64_t mnt_id, uint64_t mnt_ns_id, > uint64_t last_mnt_id, uint64_t list[], size_t num, > unsigned int flags) > { > -- > 2.48.1 >
On Fri, 07 Mar 2025 21:40:45 +0100, Miklos Szeredi wrote: > Provide coverage for all mnt_notify_add() instances. > > Applied to the vfs-6.15.mount branch of the vfs/vfs.git tree. Patches in the vfs-6.15.mount branch should appear in linux-next soon. Please report any outstanding bugs that were missed during review in a new review to the original patch series allowing us to drop it. It's encouraged to provide Acked-bys and Reviewed-bys even though the patch has now been applied. If possible patch trailers will be updated. Note that commit hashes shown below are subject to change due to rebase, trailer updates or similar. If in doubt, please check the listed branch. tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git branch: vfs-6.15.mount [1/1] selftests: add tests for mount notification https://git.kernel.org/vfs/vfs/c/a0359e49cb43
On Sat, 8 Mar 2025 at 13:10, Christian Brauner <brauner@kernel.org> wrote: > setup_namespace() can just be called on each FIXTURE_SETUP() invocation > and cleanup_namespace() on each FIXTURE_TEARDOWN(). They will always > start with a clean slate this way. Ah, hadn't realized that each test case will get a fresh process... Attached further cleanup with this in mind. Thanks, Miklos
On Mon, Mar 10, 2025 at 12:00:43PM +0100, Miklos Szeredi wrote: > On Sat, 8 Mar 2025 at 13:10, Christian Brauner <brauner@kernel.org> wrote: > > > setup_namespace() can just be called on each FIXTURE_SETUP() invocation > > and cleanup_namespace() on each FIXTURE_TEARDOWN(). They will always > > start with a clean slate this way. > > Ah, hadn't realized that each test case will get a fresh process... > > Attached further cleanup with this in mind. Thanks! I've folded this into the patch! Christian
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 8daac70c2f9d..2ebaf5e6942e 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -35,6 +35,7 @@ TARGETS += filesystems/epoll TARGETS += filesystems/fat TARGETS += filesystems/overlayfs TARGETS += filesystems/statmount +TARGETS += filesystems/mount-notify TARGETS += firmware TARGETS += fpu TARGETS += ftrace diff --git a/tools/testing/selftests/filesystems/mount-notify/.gitignore b/tools/testing/selftests/filesystems/mount-notify/.gitignore new file mode 100644 index 000000000000..82a4846cbc4b --- /dev/null +++ b/tools/testing/selftests/filesystems/mount-notify/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +/*_test diff --git a/tools/testing/selftests/filesystems/mount-notify/Makefile b/tools/testing/selftests/filesystems/mount-notify/Makefile new file mode 100644 index 000000000000..10be0227b5ae --- /dev/null +++ b/tools/testing/selftests/filesystems/mount-notify/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0-or-later + +CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) +TEST_GEN_PROGS := mount-notify_test + +include ../../lib.mk diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c new file mode 100644 index 000000000000..d39ff57bf163 --- /dev/null +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c @@ -0,0 +1,586 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +// Copyright (c) 2025 Miklos Szeredi <miklos@szeredi.hu> + +#define _GNU_SOURCE +#include <fcntl.h> +#include <sched.h> +#include <stdio.h> +#include <string.h> +#include <sys/stat.h> +#include <sys/mount.h> +#include <linux/fanotify.h> +#include <unistd.h> +#include <sys/fanotify.h> +#include <sys/syscall.h> + +#include "../../kselftest_harness.h" +#include "../statmount/statmount.h" + +static char root_mntpoint[] = "/tmp/mount-notify_test_root.XXXXXX"; +static int orig_root, ns_fd; +static uint64_t root_id; + +static uint64_t get_mnt_id(const char *path) +{ + struct statx sx; + int ret; + + ret = statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx); + if (ret == -1) + ksft_exit_fail_perror("retrieving mount ID"); + + if (!(sx.stx_mask & STATX_MNT_ID_UNIQUE)) + ksft_exit_fail_msg("no mount ID available\n"); + + return sx.stx_mnt_id; +} + +static void cleanup_namespace(void) +{ + int ret; + + ret = fchdir(orig_root); + if (ret == -1) + ksft_perror("fchdir to original root"); + + ret = chroot("."); + if (ret == -1) + ksft_perror("chroot to original root"); + + umount2(root_mntpoint, MNT_DETACH); + chdir(root_mntpoint); + rmdir("a"); + rmdir("b"); + chdir("/"); + rmdir(root_mntpoint); +} + +static void setup_namespace(void) +{ + int ret; + + ret = unshare(CLONE_NEWNS); + if (ret == -1) + ksft_exit_fail_perror("unsharing mountns and userns"); + + ns_fd = open("/proc/self/ns/mnt", O_RDONLY); + if (ns_fd == -1) + ksft_exit_fail_perror("opening /proc/self/ns/mnt"); + + ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL); + if (ret == -1) + ksft_exit_fail_perror("making mount tree private"); + + if (!mkdtemp(root_mntpoint)) + ksft_exit_fail_perror("creating temporary directory"); + + orig_root = open("/", O_PATH); + if (orig_root == -1) + ksft_exit_fail_perror("opening root directory"); + + atexit(cleanup_namespace); + + ret = mount(root_mntpoint, root_mntpoint, NULL, MS_BIND, NULL); + if (ret == -1) + ksft_exit_fail_perror("mounting temp root"); + + ret = chroot(root_mntpoint); + if (ret == -1) + ksft_exit_fail_perror("chroot to temp root"); + + ret = chdir("/"); + if (ret == -1) + ksft_exit_fail_perror("chdir to root"); + + ret = mkdir("a", 0700); + if (ret == -1) + ksft_exit_fail_perror("mkdir(a)"); + + ret = mkdir("b", 0700); + if (ret == -1) + ksft_exit_fail_perror("mkdir(b)"); + + root_id = get_mnt_id("/"); +} + +FIXTURE(fanotify) { + int fan_fd; + char buf[256]; + unsigned int rem; + void *next; +}; + +#define MAX_MNTS 256 +#define MAX_PATH 256 + +FIXTURE_SETUP(fanotify) +{ + uint64_t list[MAX_MNTS]; + ssize_t num; + size_t bufsize = sizeof(struct statmount) + MAX_PATH; + struct statmount *buf = alloca(bufsize); + unsigned int i; + int ret; + + // Clean up mount tree + ret = mount("", "/", NULL, MS_PRIVATE, NULL); + ASSERT_EQ(ret, 0); + + num = listmount(LSMT_ROOT, 0, 0, list, MAX_MNTS, 0); + ASSERT_GE(num, 1); + ASSERT_LT(num, MAX_MNTS); + + for (i = 0; i < num; i++) { + if (list[i] == root_id) + continue; + ret = statmount(list[i], 0, STATMOUNT_MNT_POINT, buf, bufsize, 0); + if (ret == 0 && buf->mask & STATMOUNT_MNT_POINT) + umount2(buf->str + buf->mnt_point, MNT_DETACH); + } + num = listmount(LSMT_ROOT, 0, 0, list, 2, 0); + ASSERT_EQ(num, 1); + ASSERT_EQ(list[0], root_id); + + mkdir("/a", 0700); + mkdir("/b", 0700); + + self->fan_fd = fanotify_init(FAN_REPORT_MNT, 0); + ASSERT_GE(self->fan_fd, 0); + + ret = fanotify_mark(self->fan_fd, FAN_MARK_ADD | FAN_MARK_MNTNS, + FAN_MNT_ATTACH | FAN_MNT_DETACH, ns_fd, NULL); + ASSERT_EQ(ret, 0); + + self->rem = 0; +} + +FIXTURE_TEARDOWN(fanotify) +{ + ASSERT_EQ(self->rem, 0); + close(self->fan_fd); +} + +static uint64_t expect_notify(struct __test_metadata *const _metadata, + FIXTURE_DATA(fanotify) *self, + uint64_t *mask) +{ + struct fanotify_event_metadata *meta; + struct fanotify_event_info_mnt *mnt; + unsigned int thislen; + + if (!self->rem) { + ssize_t len = read(self->fan_fd, self->buf, sizeof(self->buf)); + ASSERT_GT(len, 0); + + self->rem = len; + self->next = (void *) self->buf; + } + + meta = self->next; + ASSERT_TRUE(FAN_EVENT_OK(meta, self->rem)); + + thislen = meta->event_len; + self->rem -= thislen; + self->next += thislen; + + *mask = meta->mask; + thislen -= sizeof(*meta); + + mnt = ((void *) meta) + meta->event_len - thislen; + + ASSERT_EQ(thislen, sizeof(*mnt)); + + return mnt->mnt_id; +} + +static void expect_notify_n(struct __test_metadata *const _metadata, + FIXTURE_DATA(fanotify) *self, + unsigned int n, uint64_t mask[], uint64_t mnts[]) +{ + unsigned int i; + + for (i = 0; i < n; i++) + mnts[i] = expect_notify(_metadata, self, &mask[i]); +} + +static uint64_t expect_notify_mask(struct __test_metadata *const _metadata, + FIXTURE_DATA(fanotify) *self, + uint64_t expect_mask) +{ + uint64_t mntid, mask; + + mntid = expect_notify(_metadata, self, &mask); + ASSERT_EQ(expect_mask, mask); + + return mntid; +} + + +static void expect_notify_mask_n(struct __test_metadata *const _metadata, + FIXTURE_DATA(fanotify) *self, + uint64_t mask, unsigned int n, uint64_t mnts[]) +{ + unsigned int i; + + for (i = 0; i < n; i++) + mnts[i] = expect_notify_mask(_metadata, self, mask); +} + + +static void verify_mount_ids(struct __test_metadata *const _metadata, + const uint64_t list1[], const uint64_t list2[], + size_t num) +{ + unsigned int i, j; + + // Check that neither list has any duplicates + for (i = 0; i < num; i++) { + for (j = 0; j < num; j++) { + if (i != j) { + ASSERT_NE(list1[i], list1[j]); + ASSERT_NE(list2[i], list2[j]); + } + } + } + // Check that all list1 memebers can be found in list2. Together with + // the above it means that the list1 and list2 represent the same sets. + for (i = 0; i < num; i++) { + for (j = 0; j < num; j++) { + if (list1[i] == list2[j]) + break; + } + ASSERT_NE(j, num); + } +} + +static void check_mounted(struct __test_metadata *const _metadata, + const uint64_t mnts[], size_t num) +{ + ssize_t ret; + uint64_t *list; + + list = malloc((num + 1) * sizeof(list[0])); + ASSERT_NE(list, NULL); + + ret = listmount(LSMT_ROOT, 0, 0, list, num + 1, 0); + ASSERT_EQ(ret, num); + + verify_mount_ids(_metadata, mnts, list, num); + + free(list); +} + +static void setup_mount_tree(struct __test_metadata *const _metadata, + int log2_num) +{ + int ret, i; + + ret = mount("", "/", NULL, MS_SHARED, NULL); + ASSERT_EQ(ret, 0); + + for (i = 0; i < log2_num; i++) { + ret = mount("/", "/", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + } +} + +TEST_F(fanotify, bind) +{ + int ret; + uint64_t mnts[2] = { root_id }; + + ret = mount("/", "/", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + ASSERT_NE(mnts[0], mnts[1]); + + check_mounted(_metadata, mnts, 2); + + // Cleanup + uint64_t detach_id; + ret = umount("/"); + ASSERT_EQ(ret, 0); + + detach_id = expect_notify_mask(_metadata, self, FAN_MNT_DETACH); + ASSERT_EQ(detach_id, mnts[1]); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, move) +{ + int ret; + uint64_t mnts[2] = { root_id }; + uint64_t move_id; + + ret = mount("/", "/a", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + ASSERT_NE(mnts[0], mnts[1]); + + check_mounted(_metadata, mnts, 2); + + ret = move_mount(AT_FDCWD, "/a", AT_FDCWD, "/b", 0); + ASSERT_EQ(ret, 0); + + move_id = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH | FAN_MNT_DETACH); + ASSERT_EQ(move_id, mnts[1]); + + // Cleanup + ret = umount("/b"); + ASSERT_EQ(ret, 0); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, propagate) +{ + const unsigned int log2_num = 4; + const unsigned int num = (1 << log2_num); + uint64_t mnts[num]; + + setup_mount_tree(_metadata, log2_num); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, num - 1, mnts + 1); + + mnts[0] = root_id; + check_mounted(_metadata, mnts, num); + + // Cleanup + int ret; + uint64_t mnts2[num]; + ret = umount2("/", MNT_DETACH); + ASSERT_EQ(ret, 0); + + ret = mount("", "/", NULL, MS_PRIVATE, NULL); + ASSERT_EQ(ret, 0); + + mnts2[0] = root_id; + expect_notify_mask_n(_metadata, self, FAN_MNT_DETACH, num - 1, mnts2 + 1); + verify_mount_ids(_metadata, mnts, mnts2, num); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, fsmount) +{ + int ret, fs, mnt; + uint64_t mnts[2] = { root_id }; + + fs = fsopen("tmpfs", 0); + ASSERT_GE(fs, 0); + + ret = fsconfig(fs, FSCONFIG_CMD_CREATE, 0, 0, 0); + ASSERT_EQ(ret, 0); + + mnt = fsmount(fs, 0, 0); + ASSERT_GE(mnt, 0); + + close(fs); + + ret = move_mount(mnt, "", AT_FDCWD, "/a", MOVE_MOUNT_F_EMPTY_PATH); + ASSERT_EQ(ret, 0); + + close(mnt); + + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + ASSERT_NE(mnts[0], mnts[1]); + + check_mounted(_metadata, mnts, 2); + + // Cleanup + uint64_t detach_id; + ret = umount("/a"); + ASSERT_EQ(ret, 0); + + detach_id = expect_notify_mask(_metadata, self, FAN_MNT_DETACH); + ASSERT_EQ(detach_id, mnts[1]); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, reparent) +{ + uint64_t mnts[6] = { root_id }; + uint64_t dmnts[3]; + uint64_t masks[3]; + unsigned int i; + int ret; + + // Create setup with a[1] -> b[2] propagation + ret = mount("/", "/a", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + ret = mount("", "/a", NULL, MS_SHARED, NULL); + ASSERT_EQ(ret, 0); + + ret = mount("/a", "/b", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + ret = mount("", "/b", NULL, MS_SLAVE, NULL); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, 2, mnts + 1); + + check_mounted(_metadata, mnts, 3); + + // Mount on a[3], which is propagated to b[4] + ret = mount("/", "/a", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, 2, mnts + 3); + + check_mounted(_metadata, mnts, 5); + + // Mount on b[5], not propagated + ret = mount("/", "/b", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + mnts[5] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + + check_mounted(_metadata, mnts, 6); + + // Umount a[3], which is propagated to b[4], but not b[5] + // This will result in b[5] "falling" on b[2] + ret = umount("/a"); + ASSERT_EQ(ret, 0); + + expect_notify_n(_metadata, self, 3, masks, dmnts); + verify_mount_ids(_metadata, mnts + 3, dmnts, 3); + + for (i = 0; i < 3; i++) { + if (dmnts[i] == mnts[5]) { + ASSERT_EQ(masks[i], FAN_MNT_ATTACH | FAN_MNT_DETACH); + } else { + ASSERT_EQ(masks[i], FAN_MNT_DETACH); + } + } + + mnts[3] = mnts[5]; + check_mounted(_metadata, mnts, 4); + + // Cleanup + ret = umount("/b"); + ASSERT_EQ(ret, 0); + + ret = umount("/a"); + ASSERT_EQ(ret, 0); + + ret = umount("/b"); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_DETACH, 3, dmnts); + verify_mount_ids(_metadata, mnts + 1, dmnts, 3); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, rmdir) +{ + uint64_t mnts[3] = { root_id }; + int ret; + + ret = mount("/", "/a", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + ret = mount("/", "/a/b", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, 2, mnts + 1); + + check_mounted(_metadata, mnts, 3); + + ret = chdir("/a"); + ASSERT_EQ(ret, 0); + + ret = fork(); + ASSERT_GE(ret, 0); + + if (ret == 0) { + chdir("/"); + unshare(CLONE_NEWNS); + mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL); + umount2("/a", MNT_DETACH); + // This triggers a detach in the other namespace + rmdir("/a"); + exit(0); + } + wait(NULL); + + expect_notify_mask_n(_metadata, self, FAN_MNT_DETACH, 2, mnts + 1); + check_mounted(_metadata, mnts, 1); + + // Cleanup + ret = chdir("/"); + ASSERT_EQ(ret, 0); + + ret = mkdir("a", 0700); + ASSERT_EQ(ret, 0); +} + +TEST_F(fanotify, pivot_root) +{ + uint64_t mnts[3] = { root_id }; + uint64_t mnts2[3]; + int ret; + + ret = mount("tmpfs", "/a", "tmpfs", 0, NULL); + ASSERT_EQ(ret, 0); + + mnts[2] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + + ret = mkdir("/a/new", 0700); + ASSERT_EQ(ret, 0); + + ret = mkdir("/a/old", 0700); + ASSERT_EQ(ret, 0); + + ret = mount("/a", "/a/new", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + check_mounted(_metadata, mnts, 3); + + ret = syscall(SYS_pivot_root, "/a/new", "/a/new/old"); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH | FAN_MNT_DETACH, 2, mnts2); + verify_mount_ids(_metadata, mnts, mnts2, 2); + check_mounted(_metadata, mnts, 3); + + // Cleanup + ret = syscall(SYS_pivot_root, "/old", "/old/a/new"); + ASSERT_EQ(ret, 0); + + ret = umount("/a/new"); + ASSERT_EQ(ret, 0); + + ret = umount("/a"); + ASSERT_EQ(ret, 0); + + check_mounted(_metadata, mnts, 1); +} + +int main(int argc, char *argv[]) +{ + int ret; + + ksft_print_header(); + + if (geteuid()) + ksft_exit_skip("mount notify requires root privileges\n"); + + ret = fanotify_init(FAN_REPORT_MNT, 0); + if (ret == -1) { + if (errno == EINVAL) + ksft_exit_skip("FAN_REPORT_MNT not supported\n"); + ksft_exit_fail_perror("fanotify_init(FAN_REPORT_MNT, 0)"); + } + close(ret); + + setup_namespace(); + + return test_harness_run(argc, argv); +} diff --git a/tools/testing/selftests/filesystems/statmount/statmount.h b/tools/testing/selftests/filesystems/statmount/statmount.h index f4294bab9d73..a7a5289ddae9 100644 --- a/tools/testing/selftests/filesystems/statmount/statmount.h +++ b/tools/testing/selftests/filesystems/statmount/statmount.h @@ -25,7 +25,7 @@ static inline int statmount(uint64_t mnt_id, uint64_t mnt_ns_id, uint64_t mask, return syscall(__NR_statmount, &req, buf, bufsize, flags); } -static ssize_t listmount(uint64_t mnt_id, uint64_t mnt_ns_id, +static inline ssize_t listmount(uint64_t mnt_id, uint64_t mnt_ns_id, uint64_t last_mnt_id, uint64_t list[], size_t num, unsigned int flags) {
Provide coverage for all mnt_notify_add() instances. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> --- tools/testing/selftests/Makefile | 1 + .../filesystems/mount-notify/.gitignore | 2 + .../filesystems/mount-notify/Makefile | 6 + .../mount-notify/mount-notify_test.c | 586 ++++++++++++++++++ .../filesystems/statmount/statmount.h | 2 +- 5 files changed, 596 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/filesystems/mount-notify/.gitignore create mode 100644 tools/testing/selftests/filesystems/mount-notify/Makefile create mode 100644 tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c