diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 00000000..6c9acb3f
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,32 @@
+name: Test Suite
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    name: Build and test
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Set up Git repository
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get -q update
+          sudo apt-get -q -y install --no-install-recommends \
+            build-essential automake autoconf libtool pkg-config \
+            icu-devtools libicu-dev libxml2-dev uuid-dev libsnmp-dev \
+            libfuse-dev attr
+          sudo install -m 755 tests/docker/icu-config /usr/local/bin/icu-config
+
+      - name: Build
+        run: |
+          ./autogen.sh
+          ./configure --enable-icu-6x
+          make -j"$(nproc)"
+
+      - name: Run tests
+        run: make check VERBOSE=1 || { cat tests/test-suite.log; exit 1; }
diff --git a/.gitignore b/.gitignore
index 0711b11e..61537161 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,3 +32,10 @@ GTAGS
 TAGS
 tags
 *~
+# Files generated by make check
+tests/t/*.log
+tests/t/*.trs
+tests/test-suite.log
+build.log
+configure.log
+tests/helpers/fsops_helper
diff --git a/Makefile.am b/Makefile.am
index 31ff904c..fe8f55a4 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -37,7 +37,7 @@ ACLOCAL_AMFLAGS = -I m4
 
 nobase_pkginclude_HEADERS = config.h
 
-SUBDIRS = messages src conf init.d man
+SUBDIRS = messages src conf init.d man tests
 
 install-data-local: ltfs.pc
 	if [ ! -d $(DESTDIR)$(libdir)/pkgconfig ]; then \
diff --git a/configure.ac b/configure.ac
index f28d2b28..ef5cd3d9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -601,6 +601,11 @@ dnl
 dnl Output files
 dnl
 AC_CONFIG_HEADERS([config.h])
+dnl Compute the integration test list at configure time so branches can
+dnl add tests/t/*.sh scripts without editing the build files.
+TESTS_LIST=`cd "$srcdir/tests" 2>/dev/null && ls t/*.sh 2>/dev/null | sort | tr '\n' ' '`
+AC_SUBST([TESTS_LIST])
+
 AC_CONFIG_FILES([
     Makefile
     messages/Makefile
@@ -619,6 +624,7 @@ AC_CONFIG_FILES([
     src/iosched/Makefile
     src/kmi/Makefile
     src/utils/Makefile
+    tests/Makefile
     ltfs.pc:ltfs.pc.in
 ])
 
diff --git a/src/libltfs/arch/ltfs_arch_ops.h b/src/libltfs/arch/ltfs_arch_ops.h
index 242d6dc8..7c4684ad 100644
--- a/src/libltfs/arch/ltfs_arch_ops.h
+++ b/src/libltfs/arch/ltfs_arch_ops.h
@@ -151,7 +151,10 @@ extern "C" {
 
     #define arch_sscanf     sscanf
 
-    #define arch_open( descriptor_ptr, filename_ptr, open_flg, share_flg, unused) do{ *descriptor_ptr = open(filename_ptr, open_flg, share_flg); }while(0)
+    /* Share flags are a Windows concept; on POSIX the permission argument
+     * is the mode passed to open(2). Passing the share flag as the mode
+     * created write-only (0200) files, unreadable for non-root users. */
+    #define arch_open( descriptor_ptr, filename_ptr, open_flg, share_flg, perm) do{ *descriptor_ptr = open(filename_ptr, open_flg, perm); }while(0)
 
     #define arch_fopen(file, mode, file_ptr)  do {file_ptr = fopen(file, mode);}while(0)
 
diff --git a/tests/Makefile.am b/tests/Makefile.am
new file mode 100644
index 00000000..9015f115
--- /dev/null
+++ b/tests/Makefile.am
@@ -0,0 +1,31 @@
+#
+# Integration tests for LTFS using the file tape backend.
+#
+# Run with: make check
+# The tests need a Linux host with /dev/fuse; elsewhere they are skipped.
+# On macOS use tests/run-in-docker.sh to run them in a Linux container.
+#
+
+TEST_EXTENSIONS = .sh
+SH_LOG_COMPILER = $(SHELL)
+
+AM_TESTS_ENVIRONMENT = \
+	top_builddir='$(abs_top_builddir)' top_srcdir='$(abs_top_srcdir)'; \
+	export top_builddir top_srcdir;
+
+check_PROGRAMS = helpers/fsops_helper
+helpers_fsops_helper_SOURCES = helpers/fsops_helper.c
+
+# The test list is computed at configure time (TESTS_LIST in configure.ac)
+# so feature branches can ship additional t/*.sh scripts without editing
+# the build files; ctest registers them the same way. GNU make functions
+# cannot be used here: automake runs with -Wall -Werror, which rejects
+# them as non-POSIX.
+TESTS = $(TESTS_LIST)
+
+EXTRA_DIST = \
+	lib/harness.sh \
+	$(TESTS) \
+	docker/Dockerfile \
+	docker/icu-config \
+	run-in-docker.sh
diff --git a/tests/docker/Dockerfile b/tests/docker/Dockerfile
new file mode 100644
index 00000000..3e2b774c
--- /dev/null
+++ b/tests/docker/Dockerfile
@@ -0,0 +1,16 @@
+FROM ubuntu:24.04
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get -q update && apt-get -q -y install --no-install-recommends \
+        build-essential automake autoconf libtool pkg-config \
+        icu-devtools libicu-dev libxml2-dev uuid-dev libsnmp-dev \
+        libfuse-dev fuse3 libfuse3-dev \
+        attr file procps util-linux tar \
+    && rm -rf /var/lib/apt/lists/*
+
+# configure.ac probes icu-config, which modern ICU no longer ships.
+COPY icu-config /usr/local/bin/icu-config
+RUN chmod +x /usr/local/bin/icu-config
+
+WORKDIR /ltfs
diff --git a/tests/docker/icu-config b/tests/docker/icu-config
new file mode 100644
index 00000000..c6af7cb8
--- /dev/null
+++ b/tests/docker/icu-config
@@ -0,0 +1,12 @@
+#!/bin/sh
+# Minimal icu-config replacement for distributions that no longer ship it.
+case "$1" in
+    --cppflags)
+        pkg-config --cflags icu-uc ;;
+    --ldflags)
+        pkg-config --libs icu-uc icu-io ;;
+    --version)
+        pkg-config --modversion icu-uc ;;
+    *)
+        echo '' ;;
+esac
diff --git a/tests/helpers/fsops_helper.c b/tests/helpers/fsops_helper.c
new file mode 100644
index 00000000..7bb6e4c1
--- /dev/null
+++ b/tests/helpers/fsops_helper.c
@@ -0,0 +1,64 @@
+/* Test helper exercising syscalls that shell utilities do not reach
+ * directly: renameat2() flags and ftruncate() on an open descriptor.
+ *
+ * Usage:
+ *   fsops_helper noreplace <old> <new>   renameat2 with RENAME_NOREPLACE
+ *   fsops_helper exchange <a> <b>        renameat2 with RENAME_EXCHANGE
+ *   fsops_helper ftruncate <file> <len>  ftruncate an open fd, print new size
+ *
+ * Exit codes: 0 = success, 2 = syscall failed (errno printed), 3 = usage.
+ */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+int main(int argc, char **argv)
+{
+	if (argc != 4) {
+		fprintf(stderr, "usage: %s noreplace|exchange|ftruncate <arg> <arg>\n",
+			argv[0]);
+		return 3;
+	}
+
+	if (!strcmp(argv[1], "noreplace") || !strcmp(argv[1], "exchange")) {
+#ifdef __linux__
+		unsigned int flags = !strcmp(argv[1], "noreplace") ?
+			RENAME_NOREPLACE : RENAME_EXCHANGE;
+
+		if (renameat2(AT_FDCWD, argv[2], AT_FDCWD, argv[3], flags) < 0) {
+			printf("%s\n", strerror(errno));
+			return 2;
+		}
+		return 0;
+#else
+		/* The integration tests only run on Linux; keep the helper
+		 * compiling on the other platforms. */
+		fprintf(stderr, "rename flags are not supported on this platform\n");
+		return 3;
+#endif
+	}
+
+	if (!strcmp(argv[1], "ftruncate")) {
+		struct stat st;
+		off_t len = strtoll(argv[3], NULL, 10);
+		int fd = open(argv[2], O_RDWR);
+
+		if (fd < 0 || ftruncate(fd, len) < 0 || fstat(fd, &st) < 0) {
+			printf("%s\n", strerror(errno));
+			return 2;
+		}
+		printf("%lld\n", (long long)st.st_size);
+		close(fd);
+		return 0;
+	}
+
+	fprintf(stderr, "unknown command: %s\n", argv[1]);
+	return 3;
+}
diff --git a/tests/lib/harness.sh b/tests/lib/harness.sh
new file mode 100644
index 00000000..1b7dab8e
--- /dev/null
+++ b/tests/lib/harness.sh
@@ -0,0 +1,195 @@
+# Common helpers for LTFS integration tests.
+#
+# Tests run against the build tree (no installation needed) using the
+# file tape backend, which emulates a tape drive in a plain directory.
+#
+# A test script sources this file, calls ltfs_setup, performs its checks
+# under $MNT, then calls ltfs_finish (unmount + ltfsck). Cleanup of
+# mounts and temporary files is handled by an EXIT trap.
+
+set -eu
+
+SKIP=77
+
+: "${top_builddir:?top_builddir must be set (run via make check)}"
+: "${top_srcdir:?top_srcdir must be set (run via make check)}"
+
+LTFS_BIN="$top_builddir/src/ltfs"
+MKLTFS_BIN="$top_builddir/src/utils/mkltfs"
+LTFSCK_BIN="$top_builddir/src/utils/ltfsck"
+
+# Extra mount options for the ltfs invocation; tests may override.
+LTFS_MOUNT_OPTS="${LTFS_MOUNT_OPTS:-}"
+
+WORK=
+LTFS_PID=
+MNT=
+TAPE=
+
+skip() {
+	echo "SKIP: $*"
+	exit "$SKIP"
+}
+
+fail() {
+	echo "FAIL: $*" >&2
+	exit 1
+}
+
+ltfs_check_env() {
+	[ "$(uname -s)" = "Linux" ] || skip "FUSE integration tests only run on Linux"
+	[ -e /dev/fuse ] || skip "/dev/fuse is not available"
+	command -v fusermount3 >/dev/null 2>&1 || command -v fusermount >/dev/null 2>&1 \
+		|| [ "$(id -u)" = "0" ] || skip "fusermount is not available"
+	[ -x "$LTFS_BIN" ] || fail "ltfs binary not found at $LTFS_BIN"
+	[ -x "$MKLTFS_BIN" ] || fail "mkltfs binary not found at $MKLTFS_BIN"
+	[ -x "$LTFSCK_BIN" ] || fail "ltfsck binary not found at $LTFSCK_BIN"
+}
+
+_fusermount() {
+	if command -v fusermount3 >/dev/null 2>&1; then
+		fusermount3 "$@"
+	elif command -v fusermount >/dev/null 2>&1; then
+		fusermount "$@"
+	else
+		# root can unmount directly
+		shift  # drop -u
+		umount "$@"
+	fi
+}
+
+ltfs_cleanup() {
+	status=$?
+	set +e
+	if [ -n "$MNT" ] && mountpoint -q "$MNT" 2>/dev/null; then
+		_fusermount -u "$MNT" 2>/dev/null || umount "$MNT" 2>/dev/null
+	fi
+	if [ -n "$LTFS_PID" ] && kill -0 "$LTFS_PID" 2>/dev/null; then
+		# Give the daemon time to flush the index after unmount.
+		for _ in $(seq 50); do
+			kill -0 "$LTFS_PID" 2>/dev/null || break
+			sleep 0.2
+		done
+		kill "$LTFS_PID" 2>/dev/null
+	fi
+	[ -n "$WORK" ] && rm -rf "$WORK"
+	exit "$status"
+}
+
+# Locate a built plugin .so, accepting both the autotools (libtool .libs/)
+# and the CMake (plain subdir) layouts.
+_find_plugin() {
+	subdir=$1
+	base=$2
+	for cand in \
+		"$top_builddir/src/$subdir/.libs/$base.so" \
+		"$top_builddir/src/$subdir/$base.so"; do
+		if [ -f "$cand" ]; then
+			echo "$cand"
+			return 0
+		fi
+	done
+	fail "plugin $base.so not found under $top_builddir/src/$subdir"
+}
+
+# Generate an ltfs.conf pointing at the plugins in the build tree.
+_write_config() {
+	cat >"$WORK/ltfs.conf" <<EOF
+plugin tape file $(_find_plugin tape_drivers/generic/file libtape-file)
+plugin iosched unified $(_find_plugin iosched libiosched-unified)
+plugin iosched fcfs $(_find_plugin iosched libiosched-fcfs)
+plugin kmi flatfile $(_find_plugin kmi libkmi-flatfile)
+plugin kmi simple $(_find_plugin kmi libkmi-simple)
+default tape file
+default iosched unified
+default kmi none
+EOF
+}
+
+# ltfs_setup: format a file-backend tape and mount it on $MNT.
+ltfs_setup() {
+	ltfs_check_env
+
+	WORK=$(mktemp -d "${TMPDIR:-/tmp}/ltfstest.XXXXXX")
+	trap ltfs_cleanup EXIT INT TERM
+	MNT="$WORK/mnt"
+	TAPE="$WORK/tape"
+	mkdir -p "$MNT" "$TAPE"
+
+	_write_config
+
+	"$MKLTFS_BIN" -i "$WORK/ltfs.conf" -e file -d "$TAPE" -n testvol -f \
+		>"$WORK/mkltfs.log" 2>&1 || {
+		cat "$WORK/mkltfs.log" >&2
+		fail "mkltfs failed"
+	}
+
+	# Run in the foreground so we keep the pid and the log.
+	# shellcheck disable=SC2086
+	"$LTFS_BIN" "$MNT" -o config_file="$WORK/ltfs.conf" -o tape_backend=file \
+		-o devname="$TAPE" $LTFS_MOUNT_OPTS -f >"$WORK/ltfs.log" 2>&1 &
+	LTFS_PID=$!
+
+	for _ in $(seq 150); do
+		mountpoint -q "$MNT" && return 0
+		kill -0 "$LTFS_PID" 2>/dev/null || break
+		sleep 0.2
+	done
+	cat "$WORK/ltfs.log" >&2
+	fail "ltfs did not mount within timeout"
+}
+
+# ltfs_umount: unmount and wait for the daemon to flush and exit.
+ltfs_umount() {
+	_fusermount -u "$MNT"
+	for _ in $(seq 150); do
+		kill -0 "$LTFS_PID" 2>/dev/null || { LTFS_PID=; return 0; }
+		sleep 0.2
+	done
+	cat "$WORK/ltfs.log" >&2
+	fail "ltfs daemon did not exit after unmount"
+}
+
+# ltfs_fsck: verify the volume is consistent.
+# Exit codes follow fsck conventions: 0 = clean, 1 = corrected/treat as
+# success (e.g. MAM coherency update); anything else is a failure.
+ltfs_fsck() {
+	rc=0
+	"$LTFSCK_BIN" -i "$WORK/ltfs.conf" -e file "$TAPE" >"$WORK/ltfsck.log" 2>&1 || rc=$?
+	if [ "$rc" -gt 1 ]; then
+		cat "$WORK/ltfsck.log" >&2
+		fail "ltfsck reported errors (exit $rc)"
+	fi
+	grep -q "Volume is consistent" "$WORK/ltfsck.log" || {
+		cat "$WORK/ltfsck.log" >&2
+		fail "ltfsck did not report a consistent volume"
+	}
+}
+
+# ltfs_finish: standard end of test (unmount + consistency check).
+ltfs_finish() {
+	ltfs_umount
+	ltfs_fsck
+}
+
+# ltfs_is_fuse3: true when the ltfs binary is linked against libfuse 3.
+ltfs_is_fuse3() {
+	{ ldd "$LTFS_BIN" 2>/dev/null || ldd "$top_builddir/src/.libs/ltfs" 2>/dev/null; } \
+		| grep -q libfuse3
+}
+
+# ltfs_remount: unmount and mount again (e.g. to verify persistence).
+ltfs_remount() {
+	ltfs_umount
+	# shellcheck disable=SC2086
+	"$LTFS_BIN" "$MNT" -o config_file="$WORK/ltfs.conf" -o tape_backend=file \
+		-o devname="$TAPE" $LTFS_MOUNT_OPTS -f >"$WORK/ltfs-remount.log" 2>&1 &
+	LTFS_PID=$!
+	for _ in $(seq 150); do
+		mountpoint -q "$MNT" && return 0
+		kill -0 "$LTFS_PID" 2>/dev/null || break
+		sleep 0.2
+	done
+	cat "$WORK/ltfs-remount.log" >&2
+	fail "ltfs did not remount within timeout"
+}
diff --git a/tests/run-in-docker.sh b/tests/run-in-docker.sh
new file mode 100755
index 00000000..fe933f55
--- /dev/null
+++ b/tests/run-in-docker.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+# Build LTFS and run the test suite inside a Linux container.
+# FUSE mounts require /dev/fuse and CAP_SYS_ADMIN in the container.
+#
+# Usage: tests/run-in-docker.sh [configure-options...]
+#   e.g. tests/run-in-docker.sh --with-fuse2
+# Environment:
+#   LTFS_DOCKER_SHELL=1   drop into an interactive shell instead of building
+
+set -eu
+
+top_srcdir=$(cd "$(dirname "$0")/.." && pwd)
+image=ltfs-test
+
+docker build -q -t "$image" "$top_srcdir/tests/docker" >/dev/null
+
+run_flags="--rm --device /dev/fuse --cap-add SYS_ADMIN --security-opt apparmor:unconfined"
+
+if [ "${LTFS_DOCKER_SHELL:-0}" = "1" ]; then
+    # shellcheck disable=SC2086
+    exec docker run $run_flags -it -v "$top_srcdir:/ltfs" "$image" bash
+fi
+
+# shellcheck disable=SC2086
+exec docker run $run_flags -v "$top_srcdir:/ltfs" "$image" sh -ec "
+    ./autogen.sh
+    ./configure --enable-icu-6x $*
+    make -j\$(nproc)
+    make check VERBOSE=1
+"
diff --git a/tests/t/00-mount-umount.sh b/tests/t/00-mount-umount.sh
new file mode 100755
index 00000000..072c18da
--- /dev/null
+++ b/tests/t/00-mount-umount.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+# Format, mount, unmount, fsck: the volume must be consistent and empty.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+mountpoint -q "$MNT" || fail "mountpoint not active"
+[ -z "$(ls -A "$MNT")" ] || fail "freshly formatted volume is not empty"
+
+df -P "$MNT" | grep -q "$MNT" || fail "statfs does not report the volume"
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/01-io-roundtrip.sh b/tests/t/01-io-roundtrip.sh
new file mode 100755
index 00000000..61531ee9
--- /dev/null
+++ b/tests/t/01-io-roundtrip.sh
@@ -0,0 +1,34 @@
+#!/bin/sh
+# Write files of various sizes, verify checksums before and after remount.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+mkdir "$MNT/data"
+
+# Small, block-sized, and multi-megabyte files
+dd if=/dev/urandom of="$WORK/small" bs=1234 count=1 status=none
+dd if=/dev/urandom of="$WORK/medium" bs=512K count=1 status=none
+dd if=/dev/urandom of="$WORK/large" bs=1M count=8 status=none
+
+for f in small medium large; do
+	cp "$WORK/$f" "$MNT/data/$f"
+done
+
+( cd "$WORK" && sha256sum small medium large >"$WORK/sums" )
+( cd "$MNT/data" && sha256sum -c "$WORK/sums" >/dev/null ) \
+	|| fail "checksum mismatch while mounted"
+
+# Overwrite in place and append
+printf 'rewrite' | dd of="$MNT/data/small" bs=1 seek=10 conv=notrunc status=none
+cat "$WORK/small" >>"$MNT/data/medium"
+
+ltfs_remount
+
+( cd "$MNT/data" && sha256sum large ) | (cd "$WORK" && sha256sum -c >/dev/null) \
+	|| fail "checksum mismatch after remount"
+[ "$(stat -c %s "$MNT/data/medium")" -eq $((524288 + 1234)) ] \
+	|| fail "appended size wrong after remount"
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/02-truncate.sh b/tests/t/02-truncate.sh
new file mode 100755
index 00000000..9055eb05
--- /dev/null
+++ b/tests/t/02-truncate.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+# Truncate by path (shrink and extend) and verify content and size.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+dd if=/dev/urandom of="$MNT/file" bs=1M count=2 status=none
+
+truncate -s 1M "$MNT/file"
+[ "$(stat -c %s "$MNT/file")" -eq 1048576 ] || fail "shrink truncate size"
+
+truncate -s 3M "$MNT/file"
+[ "$(stat -c %s "$MNT/file")" -eq 3145728 ] || fail "extend truncate size"
+
+# Extended region must read back as zeros
+tail -c 2097152 "$MNT/file" >"$WORK/tail"
+head -c 2097152 /dev/zero >"$WORK/zeros"
+cmp -s "$WORK/tail" "$WORK/zeros" || fail "extended region not zero-filled"
+
+truncate -s 0 "$MNT/file"
+[ "$(stat -c %s "$MNT/file")" -eq 0 ] || fail "truncate to zero"
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/03-rename.sh b/tests/t/03-rename.sh
new file mode 100755
index 00000000..88783a75
--- /dev/null
+++ b/tests/t/03-rename.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+# Rename files and directories, including overwriting an existing target.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+echo one >"$MNT/a"
+echo two >"$MNT/b"
+mkdir "$MNT/dir1"
+echo nested >"$MNT/dir1/inner"
+
+# Simple rename
+mv "$MNT/a" "$MNT/a2"
+[ "$(cat "$MNT/a2")" = "one" ] || fail "simple rename content"
+[ ! -e "$MNT/a" ] || fail "source still present after rename"
+
+# Overwriting rename
+mv "$MNT/a2" "$MNT/b"
+[ "$(cat "$MNT/b")" = "one" ] || fail "overwriting rename content"
+
+# Directory rename
+mv "$MNT/dir1" "$MNT/dir2"
+[ "$(cat "$MNT/dir2/inner")" = "nested" ] || fail "directory rename content"
+
+# mv -n must not overwrite (rename(2) with RENAME_NOREPLACE on fuse3)
+echo keep >"$MNT/target"
+echo other >"$MNT/source"
+mv -n "$MNT/source" "$MNT/target" 2>/dev/null || true
+[ "$(cat "$MNT/target")" = "keep" ] || fail "mv -n overwrote existing target"
+
+ltfs_remount
+[ "$(cat "$MNT/b")" = "one" ] || fail "rename result lost after remount"
+[ "$(cat "$MNT/dir2/inner")" = "nested" ] || fail "dir rename lost after remount"
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/04-dirs-unlink.sh b/tests/t/04-dirs-unlink.sh
new file mode 100755
index 00000000..725652b1
--- /dev/null
+++ b/tests/t/04-dirs-unlink.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+# mkdir/rmdir/unlink semantics, including unlink of an open file.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+mkdir -p "$MNT/d1/d2/d3"
+[ -d "$MNT/d1/d2/d3" ] || fail "nested mkdir"
+
+echo data >"$MNT/d1/f"
+rmdir "$MNT/d1" 2>/dev/null && fail "rmdir of non-empty directory succeeded"
+
+rm "$MNT/d1/f"
+[ ! -e "$MNT/d1/f" ] || fail "unlink"
+
+rmdir "$MNT/d1/d2/d3" "$MNT/d1/d2" "$MNT/d1"
+[ ! -e "$MNT/d1" ] || fail "rmdir chain"
+
+# Unlink while open: file content must stay readable through the open fd,
+# and no .fuse_hidden* litter may remain (hard_remove semantics).
+echo openme >"$MNT/openfile"
+exec 3<"$MNT/openfile"
+rm "$MNT/openfile"
+[ ! -e "$MNT/openfile" ] || fail "unlink of open file did not remove the name"
+ls -a "$MNT" | grep -q '\.fuse_hidden' && fail ".fuse_hidden file left behind"
+exec 3<&-
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/05-xattr.sh b/tests/t/05-xattr.sh
new file mode 100755
index 00000000..07a6470a
--- /dev/null
+++ b/tests/t/05-xattr.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+# Extended attribute set/get/list/remove, persistence across remount.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+command -v setfattr >/dev/null 2>&1 || skip "attr tools not installed"
+
+echo content >"$MNT/file"
+
+setfattr -n user.test1 -v value1 "$MNT/file"
+setfattr -n user.test2 -v value2 "$MNT/file"
+
+[ "$(getfattr --only-values -n user.test1 "$MNT/file")" = "value1" ] \
+	|| fail "getxattr value"
+
+listing=$(getfattr "$MNT/file" | grep '^user\.')
+echo "$listing" | grep -q user.test1 || fail "listxattr missing user.test1"
+echo "$listing" | grep -q user.test2 || fail "listxattr missing user.test2"
+
+setfattr -x user.test2 "$MNT/file"
+getfattr "$MNT/file" 2>/dev/null | grep -q user.test2 && fail "removexattr"
+
+ltfs_remount
+[ "$(getfattr --only-values -n user.test1 "$MNT/file")" = "value1" ] \
+	|| fail "xattr lost after remount"
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/06-symlink.sh b/tests/t/06-symlink.sh
new file mode 100755
index 00000000..8adeabfe
--- /dev/null
+++ b/tests/t/06-symlink.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+# Symlink creation, readlink, and persistence.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+echo target-content >"$MNT/target"
+ln -s target "$MNT/link"
+
+[ -L "$MNT/link" ] || fail "symlink not created"
+[ "$(readlink "$MNT/link")" = "target" ] || fail "readlink value"
+[ "$(cat "$MNT/link")" = "target-content" ] || fail "read through symlink"
+
+ln -s /nonexistent/absolute "$MNT/dangling"
+[ "$(readlink "$MNT/dangling")" = "/nonexistent/absolute" ] || fail "dangling symlink"
+
+ltfs_remount
+[ "$(readlink "$MNT/link")" = "target" ] || fail "symlink lost after remount"
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/07-large-dir.sh b/tests/t/07-large-dir.sh
new file mode 100755
index 00000000..3bf003fd
--- /dev/null
+++ b/tests/t/07-large-dir.sh
@@ -0,0 +1,28 @@
+#!/bin/sh
+# readdir on a directory with many entries; attributes must match stat.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+mkdir "$MNT/big"
+i=0
+while [ $i -lt 500 ]; do
+	printf '%d' "$i" >"$MNT/big/f$i"
+	i=$((i + 1))
+done
+
+count=$(ls "$MNT/big" | wc -l)
+[ "$count" -eq 500 ] || fail "expected 500 entries, got $count"
+
+# Attributes from listing (readdirplus on fuse3) must match per-file stat
+ls_size=$(ls -l "$MNT/big/f123" | awk '{print $5}')
+stat_size=$(stat -c %s "$MNT/big/f123")
+[ "$ls_size" = "$stat_size" ] || fail "listing size != stat size"
+[ "$stat_size" -eq 3 ] || fail "unexpected file size"
+
+ltfs_remount
+count=$(ls "$MNT/big" | wc -l)
+[ "$count" -eq 500 ] || fail "entries lost after remount"
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/08-tar-roundtrip.sh b/tests/t/08-tar-roundtrip.sh
new file mode 100755
index 00000000..e95a5f67
--- /dev/null
+++ b/tests/t/08-tar-roundtrip.sh
@@ -0,0 +1,28 @@
+#!/bin/sh
+# Copy a small tree onto the volume, tar it back, and compare checksums.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+# Build a source tree with a few subdirectories and binary files
+mkdir -p "$WORK/tree/sub1/sub2"
+dd if=/dev/urandom of="$WORK/tree/a.bin" bs=100K count=1 status=none
+dd if=/dev/urandom of="$WORK/tree/sub1/b.bin" bs=300K count=1 status=none
+dd if=/dev/urandom of="$WORK/tree/sub1/sub2/c.bin" bs=700K count=1 status=none
+echo "text file" >"$WORK/tree/readme.txt"
+
+cp -r "$WORK/tree" "$MNT/tree"
+
+( cd "$WORK/tree" && find . -type f -exec sha256sum {} + | sort ) >"$WORK/src.sums"
+( cd "$MNT/tree" && find . -type f -exec sha256sum {} + | sort ) >"$WORK/dst.sums"
+cmp -s "$WORK/src.sums" "$WORK/dst.sums" || fail "tree copy checksum mismatch"
+
+# tar from the volume and extract elsewhere
+tar -C "$MNT" -cf "$WORK/vol.tar" tree
+mkdir "$WORK/extract"
+tar -C "$WORK/extract" -xf "$WORK/vol.tar"
+( cd "$WORK/extract/tree" && find . -type f -exec sha256sum {} + | sort ) >"$WORK/tar.sums"
+cmp -s "$WORK/src.sums" "$WORK/tar.sums" || fail "tar roundtrip checksum mismatch"
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/09-rename-flags-ftruncate.sh b/tests/t/09-rename-flags-ftruncate.sh
new file mode 100755
index 00000000..5eae6014
--- /dev/null
+++ b/tests/t/09-rename-flags-ftruncate.sh
@@ -0,0 +1,46 @@
+#!/bin/sh
+# rename(2) flag semantics, ftruncate on an open fd, and inode stability.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+HELPER="$top_builddir/tests/helpers/fsops_helper"
+
+ltfs_setup
+
+[ -x "$HELPER" ] || fail "fsops_helper not built"
+
+echo one >"$MNT/a"
+echo two >"$MNT/b"
+
+# RENAME_NOREPLACE with an existing target must fail and leave it intact
+"$HELPER" noreplace "$MNT/a" "$MNT/b" && fail "RENAME_NOREPLACE overwrote target"
+[ "$(cat "$MNT/b")" = "two" ] || fail "target changed by failed RENAME_NOREPLACE"
+[ "$(cat "$MNT/a")" = "one" ] || fail "source changed by failed RENAME_NOREPLACE"
+
+# RENAME_EXCHANGE is not supported by LTFS; it must fail without touching data
+"$HELPER" exchange "$MNT/a" "$MNT/b" && fail "RENAME_EXCHANGE unexpectedly succeeded"
+[ "$(cat "$MNT/a")" = "one" ] || fail "source changed by failed RENAME_EXCHANGE"
+[ "$(cat "$MNT/b")" = "two" ] || fail "target changed by failed RENAME_EXCHANGE"
+
+if ltfs_is_fuse3; then
+	# With a free target, RENAME_NOREPLACE must succeed (fuse2 cannot
+	# express rename flags at all, so this branch is fuse3-only)
+	"$HELPER" noreplace "$MNT/a" "$MNT/c" || fail "RENAME_NOREPLACE to free target failed"
+	[ "$(cat "$MNT/c")" = "one" ] || fail "content lost by RENAME_NOREPLACE"
+	[ ! -e "$MNT/a" ] || fail "source still present after RENAME_NOREPLACE"
+	mv "$MNT/c" "$MNT/a"
+fi
+
+# ftruncate through an open descriptor
+dd if=/dev/urandom of="$MNT/file" bs=1M count=1 status=none
+out=$("$HELPER" ftruncate "$MNT/file" 12345) || fail "ftruncate failed: $out"
+[ "$out" = "12345" ] || fail "ftruncate reported size $out"
+[ "$(stat -c %s "$MNT/file")" -eq 12345 ] || fail "size after ftruncate"
+
+# Inode numbers come from the LTFS index (use_ino) and must survive a remount
+ino_before=$(stat -c %i "$MNT/file")
+ltfs_remount
+ino_after=$(stat -c %i "$MNT/file")
+[ "$ino_before" = "$ino_after" ] || fail "inode changed across remount ($ino_before -> $ino_after)"
+
+ltfs_finish
+echo "PASS"
diff --git a/tests/t/10-request-size.sh b/tests/t/10-request-size.sh
new file mode 100755
index 00000000..86f7e3f8
--- /dev/null
+++ b/tests/t/10-request-size.sh
@@ -0,0 +1,40 @@
+#!/bin/sh
+# Verify the FUSE request sizes that reach the daemon. FUSE 3 builds
+# negotiate 1 MiB requests (max_write/max_pages); FUSE 2 is limited to
+# 128 KiB with big_writes.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+# DEBUG3 logging prints "FUSE write '...' (offset=..., count=...)"
+LTFS_MOUNT_OPTS="-o verbose=6"
+
+ltfs_setup
+
+dd if=/dev/zero of="$MNT/big" bs=1M count=8 conv=fsync status=none
+
+# O_DIRECT reads bypass the readahead window, so the application's
+# request size reaches the daemon (split at the negotiated maximum)
+dd if="$MNT/big" of=/dev/null bs=1M iflag=direct status=none \
+	|| skip "O_DIRECT reads not supported on this kernel"
+
+ltfs_finish
+
+max_req() {
+	grep "FUSE $1" "$WORK/ltfs.log" | grep -o 'count=[0-9]*' | \
+		cut -d= -f2 | sort -n | tail -1
+}
+
+write_max=$(max_req write)
+read_max=$(max_req read)
+echo "largest write request: ${write_max:-none}, largest read request: ${read_max:-none}"
+
+[ -n "$write_max" ] || fail "no write requests logged"
+
+if ltfs_is_fuse3; then
+	[ "$write_max" -ge 524288 ] || fail "write requests capped at $write_max bytes"
+	[ "$read_max" -ge 524288 ] || fail "read requests capped at $read_max bytes"
+else
+	# big_writes raises the FUSE 2 limit to 128 KiB
+	[ "$write_max" -ge 65536 ] || fail "write requests capped at $write_max bytes"
+fi
+
+echo "PASS"
diff --git a/tests/t/11-direct-io.sh b/tests/t/11-direct-io.sh
new file mode 100755
index 00000000..fabf01e0
--- /dev/null
+++ b/tests/t/11-direct-io.sh
@@ -0,0 +1,37 @@
+#!/bin/sh
+# -o direct_io: data integrity without the page cache, large requests
+# even for buffered application I/O, and graceful mmap failure.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+HELPER="$top_builddir/tests/helpers/fsops_helper"
+
+LTFS_MOUNT_OPTS="-o direct_io -o verbose=6"
+
+ltfs_setup
+
+# Data integrity through the direct path, including odd sizes
+dd if=/dev/urandom of="$WORK/data" bs=37k count=9 status=none
+cp "$WORK/data" "$MNT/data"
+cmp -s "$WORK/data" "$MNT/data" || fail "data mismatch while mounted"
+
+# mmap is not available on direct-I/O files; it must fail cleanly
+out=$("$HELPER" mmap "$MNT/data" 4096) && fail "mmap unexpectedly succeeded"
+echo "mmap failed as expected: $out"
+
+# Buffered writes from the application reach the daemon at the
+# application's block size (no page-cache splitting)
+dd if=/dev/zero of="$MNT/big" bs=1M count=4 status=none
+
+ltfs_remount
+cmp -s "$WORK/data" "$MNT/data" || fail "data mismatch after remount"
+
+ltfs_finish
+
+if ltfs_is_fuse3; then
+	write_max=$(grep "FUSE write" "$WORK/ltfs.log" | grep -o 'count=[0-9]*' | \
+		cut -d= -f2 | sort -n | tail -1)
+	echo "largest write request: $write_max"
+	[ "$write_max" -ge 524288 ] || fail "direct writes capped at $write_max bytes"
+fi
+
+echo "PASS"
diff --git a/tests/t/12-readdirplus.sh b/tests/t/12-readdirplus.sh
new file mode 100755
index 00000000..216eef96
--- /dev/null
+++ b/tests/t/12-readdirplus.sh
@@ -0,0 +1,55 @@
+#!/bin/sh
+# readdirplus: listing a directory must return correct attributes and,
+# on FUSE 3, must not trigger a getattr request per entry.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+LTFS_MOUNT_OPTS="-o verbose=6"
+
+NFILES=100
+
+ltfs_setup
+
+mkdir "$MNT/big"
+i=0
+while [ $i -lt $NFILES ]; do
+	head -c $((i + 1)) /dev/zero >"$MNT/big/f$i"
+	i=$((i + 1))
+done
+
+# Remount so the listing below runs against a cold kernel cache
+ltfs_remount
+
+# Attributes reported by the listing must match per-file stat
+ls -l "$MNT/big" >"$WORK/listing"
+for n in 0 57 99; do
+	ls_size=$(awk -v f="f$n" '$NF == f {print $5}' "$WORK/listing")
+	[ "$ls_size" = "$((n + 1))" ] || fail "listing reports size $ls_size for f$n"
+	stat_size=$(stat -c %s "$MNT/big/f$n")
+	[ "$stat_size" = "$((n + 1))" ] || fail "stat reports size $stat_size for f$n"
+done
+
+ltfs_finish
+
+# "FUSE getattr/fgetattr" debug lines from the remounted instance show how
+# many attribute requests the listing needed
+getattrs=$(grep -c "FUSE f*getattr" "$WORK/ltfs-remount.log" || true)
+echo "getattr requests during ls -l of $NFILES files: $getattrs"
+
+if ltfs_is_fuse3; then
+	# readdirplus delivers attributes with the listing; without it the
+	# kernel issues one getattr (via lookup) per entry. The prefill is
+	# only effective with libfuse >= 3.17 (verified there; libfuse 3.14
+	# never sends READDIRPLUS to the high-level API), so the strict
+	# assertion is gated on the runtime library version.
+	ver=$(fusermount3 -V 2>/dev/null | grep -oE '[0-9]+\.[0-9]+' | head -1)
+	maj=${ver%%.*}
+	min=${ver#*.}
+	if [ "${maj:-0}" -gt 3 ] || { [ "${maj:-0}" -eq 3 ] && [ "${min:-0}" -ge 17 ]; }; then
+		[ "$getattrs" -lt $((NFILES / 2)) ] \
+			|| fail "expected readdirplus to suppress per-entry getattr, saw $getattrs"
+	else
+		echo "libfuse ${ver:-unknown}: readdirplus prefill not asserted (verified on >= 3.17)"
+	fi
+fi
+
+echo "PASS"
diff --git a/tests/t/13-large-write-integrity.sh b/tests/t/13-large-write-integrity.sh
new file mode 100755
index 00000000..c3631096
--- /dev/null
+++ b/tests/t/13-large-write-integrity.sh
@@ -0,0 +1,35 @@
+#!/bin/sh
+# Data integrity for single write() calls larger than the tape block size.
+#
+# A single large write exercises the I/O scheduler's request-splitting: the
+# write must be broken into block-sized cache entries without dropping the
+# tail. dd with a large bs issues one write() syscall per block, so with the
+# FUSE 3 default max_write of 1 MiB (> the 512 KiB tape block) the daemon
+# receives multi-block writes in a single request. Content is random and
+# verified byte-for-byte, before and after a remount.
+. "${top_srcdir}/tests/lib/harness.sh"
+
+ltfs_setup
+
+# One write() each, all larger than the block size, at offset 0 and beyond
+for mb in 1 4 8; do
+	dd if=/dev/urandom of="$WORK/src$mb" bs=${mb}M count=1 status=none
+	dd if="$WORK/src$mb" of="$MNT/f$mb" bs=${mb}M count=1 conv=fsync status=none
+	cmp -s "$WORK/src$mb" "$MNT/f$mb" || fail "${mb} MiB single write corrupted while mounted"
+done
+
+# Overwrite the second half of the 4 MiB file with one 2 MiB write at a
+# block-aligned non-zero offset (exercises the insert-into-list path).
+dd if=/dev/urandom of="$WORK/mid" bs=2M count=1 status=none
+dd if="$WORK/mid" of="$MNT/f4" bs=2M count=1 seek=1 conv=fsync,notrunc status=none
+head -c 2097152 "$WORK/src4" >"$WORK/f4.expect"
+cat "$WORK/mid" >>"$WORK/f4.expect"
+cmp -s "$WORK/f4.expect" "$MNT/f4" || fail "large write at non-zero offset corrupted"
+
+ltfs_remount
+
+cmp -s "$WORK/src8" "$MNT/f8" || fail "8 MiB write corrupted after remount"
+cmp -s "$WORK/f4.expect" "$MNT/f4" || fail "offset write corrupted after remount"
+
+ltfs_finish
+echo "PASS"